diff --git a/src/ReactiveUI.Fody.Helpers/ObservableAsPropertyExtensions.cs b/src/ReactiveUI.Fody.Helpers/ObservableAsPropertyExtensions.cs
index 8c4689469d..5f9b349201 100644
--- a/src/ReactiveUI.Fody.Helpers/ObservableAsPropertyExtensions.cs
+++ b/src/ReactiveUI.Fody.Helpers/ObservableAsPropertyExtensions.cs
@@ -33,8 +33,8 @@ public static class ObservableAsPropertyExtensions
         /// </exception>
         public static ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(
             this IObservable<TRet> item,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             bool deferSubscription = false,
             IScheduler? scheduler = null)
             where TObj : ReactiveObject
@@ -88,8 +88,8 @@ public static ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(
         /// </exception>
         public static ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(
             this IObservable<TRet> item,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             TRet initialValue,
             bool deferSubscription = false,
             IScheduler? scheduler = null)
diff --git a/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.net5.0.approved.txt b/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.net5.0.approved.txt
index 9596a85c02..a4a3cd4c9f 100644
--- a/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.net5.0.approved.txt
+++ b/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.net5.0.approved.txt
@@ -14,9 +14,9 @@ namespace ReactiveUI.Fody.Helpers
     }
     public static class ObservableAsPropertyExtensions
     {
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj : ReactiveUI.ReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj : ReactiveUI.ReactiveObject { }
     }
     [System.AttributeUsage(System.AttributeTargets.Property | System.AttributeTargets.All)]
diff --git a/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.netcoreapp3.1.approved.txt b/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.netcoreapp3.1.approved.txt
index 2e2c4a7cda..3a7b07a897 100644
--- a/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.netcoreapp3.1.approved.txt
+++ b/src/ReactiveUI.Fody.Tests/API/ApiApprovalTests.ReactiveUIFody.netcoreapp3.1.approved.txt
@@ -14,9 +14,9 @@ namespace ReactiveUI.Fody.Helpers
     }
     public static class ObservableAsPropertyExtensions
     {
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj : ReactiveUI.ReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToPropertyEx<TObj, TRet>(this System.IObservable<TRet> item, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj : ReactiveUI.ReactiveObject { }
     }
     [System.AttributeUsage(System.AttributeTargets.Property | System.AttributeTargets.All)]
diff --git a/src/ReactiveUI.Splat.Tests/ReactiveUI.Splat.Tests.csproj b/src/ReactiveUI.Splat.Tests/ReactiveUI.Splat.Tests.csproj
index 28a0ba56cc..787c0c38b6 100644
--- a/src/ReactiveUI.Splat.Tests/ReactiveUI.Splat.Tests.csproj
+++ b/src/ReactiveUI.Splat.Tests/ReactiveUI.Splat.Tests.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFrameworks>netcoreapp3.1;net5.0</TargetFrameworks>
@@ -10,7 +10,7 @@
 
   <ItemGroup>
     <PackageReference Include="Splat.Autofac" Version="12.*" />
-    <PackageReference Include="Splat.DryIoc" Version="11.*" />
+    <PackageReference Include="Splat.DryIoc" Version="12.*" />
     <PackageReference Include="Splat.Ninject" Version="12.*" />
   </ItemGroup>
 
diff --git a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt
index 16a1bb8b57..35f622bf4d 100644
--- a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt
+++ b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net472.approved.txt
@@ -401,27 +401,27 @@ namespace ReactiveUI
     }
     public static class OAPHCreationHelperMixin
     {
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
     }
     public sealed class ObservableAsPropertyHelper<T> : ReactiveUI.IHandleObservableErrors, Splat.IEnableLogger, System.IDisposable
@@ -608,8 +608,8 @@ namespace ReactiveUI
     }
     public static class ReactiveNotifyPropertyChangedMixin
     {
-        public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> ObservableForProperty<TSender, TValue>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue?>> property, bool beforeChange = false, bool skipInitial = true) { }
-        public static System.IObservable<TRet> ObservableForProperty<TSender, TValue, TRet>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue?>> property, System.Func<TValue?, TRet> selector, bool beforeChange = false)
+        public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> ObservableForProperty<TSender, TValue>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue>> property, bool beforeChange = false, bool skipInitial = true) { }
+        public static System.IObservable<TRet> ObservableForProperty<TSender, TValue, TRet>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue>> property, System.Func<TValue?, TRet> selector, bool beforeChange = false)
             where TSender :  class { }
         public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> SubscribeToExpressionChain<TSender, TValue>(this TSender? source, System.Linq.Expressions.Expression? expression, bool beforeChange = false, bool skipInitial = true, bool suppressWarnings = false) { }
     }
@@ -835,18 +835,18 @@ namespace ReactiveUI
     }
     public static class WhenAnyMixin
     {
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Func<ReactiveUI.IObservedChange<TSender, T1>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12?>> property12, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, ReactiveUI.IObservedChange<TSender, T12>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Func<ReactiveUI.IObservedChange<TSender, T1>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12>> property12, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, ReactiveUI.IObservedChange<TSender, T12>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
@@ -859,73 +859,73 @@ namespace ReactiveUI
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Linq.Expressions.Expression? property11, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Linq.Expressions.Expression? property11, System.Linq.Expressions.Expression? property12, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, TRet?>> property1) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Func<T1, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2>> WhenAnyValue<TSender, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Func<T1, T2, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3>> WhenAnyValue<TSender, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Func<T1, T2, T3, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4>> WhenAnyValue<TSender, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Func<T1, T2, T3, T4, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5>> WhenAnyValue<TSender, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Func<T1, T2, T3, T4, T5, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Func<T1, T2, T3, T4, T5, T6, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6, T7>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Func<T1, T2, T3, T4, T5, T6, T7, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12?>> property12, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, TRet>> property1) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Func<T1, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2>> WhenAnyValue<TSender, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Func<T1, T2, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3>> WhenAnyValue<TSender, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Func<T1, T2, T3, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4>> WhenAnyValue<TSender, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Func<T1, T2, T3, T4, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5>> WhenAnyValue<TSender, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Func<T1, T2, T3, T4, T5, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Func<T1, T2, T3, T4, T5, T6, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6, T7>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Func<T1, T2, T3, T4, T5, T6, T7, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12>> property12, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TRet> selector) { }
     }
     public static class WhenAnyObservableMixin
     {
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs12)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs12)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Func<T1?, T2?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Func<T1?, T2?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Func<T1?, T2?, T3?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Func<T1?, T2?, T3?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Func<T1?, T2?, T3?, T4?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Func<T1?, T2?, T3?, T4?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Func<T1?, T2?, T3?, T4?, T5?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Func<T1?, T2?, T3?, T4?, T5?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T12>?>> obs12, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, T12?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T12>?>> obs12, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, T12?, TRet> selector)
             where TSender :  class { }
     }
 }
diff --git a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt
index 1ca8c61df7..2368387397 100644
--- a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt
+++ b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net5.0.approved.txt
@@ -396,27 +396,27 @@ namespace ReactiveUI
     }
     public static class OAPHCreationHelperMixin
     {
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
     }
     public sealed class ObservableAsPropertyHelper<T> : ReactiveUI.IHandleObservableErrors, Splat.IEnableLogger, System.IDisposable
@@ -603,8 +603,8 @@ namespace ReactiveUI
     }
     public static class ReactiveNotifyPropertyChangedMixin
     {
-        public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> ObservableForProperty<TSender, TValue>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue?>> property, bool beforeChange = false, bool skipInitial = true) { }
-        public static System.IObservable<TRet> ObservableForProperty<TSender, TValue, TRet>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue?>> property, System.Func<TValue?, TRet> selector, bool beforeChange = false)
+        public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> ObservableForProperty<TSender, TValue>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue>> property, bool beforeChange = false, bool skipInitial = true) { }
+        public static System.IObservable<TRet> ObservableForProperty<TSender, TValue, TRet>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue>> property, System.Func<TValue?, TRet> selector, bool beforeChange = false)
             where TSender :  class { }
         public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> SubscribeToExpressionChain<TSender, TValue>(this TSender? source, System.Linq.Expressions.Expression? expression, bool beforeChange = false, bool skipInitial = true, bool suppressWarnings = false) { }
     }
@@ -830,18 +830,18 @@ namespace ReactiveUI
     }
     public static class WhenAnyMixin
     {
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Func<ReactiveUI.IObservedChange<TSender, T1>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12?>> property12, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, ReactiveUI.IObservedChange<TSender, T12>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Func<ReactiveUI.IObservedChange<TSender, T1>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12>> property12, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, ReactiveUI.IObservedChange<TSender, T12>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
@@ -854,73 +854,73 @@ namespace ReactiveUI
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Linq.Expressions.Expression? property11, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Linq.Expressions.Expression? property11, System.Linq.Expressions.Expression? property12, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, TRet?>> property1) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Func<T1, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2>> WhenAnyValue<TSender, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Func<T1, T2, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3>> WhenAnyValue<TSender, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Func<T1, T2, T3, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4>> WhenAnyValue<TSender, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Func<T1, T2, T3, T4, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5>> WhenAnyValue<TSender, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Func<T1, T2, T3, T4, T5, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Func<T1, T2, T3, T4, T5, T6, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6, T7>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Func<T1, T2, T3, T4, T5, T6, T7, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12?>> property12, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, TRet>> property1) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Func<T1, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2>> WhenAnyValue<TSender, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Func<T1, T2, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3>> WhenAnyValue<TSender, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Func<T1, T2, T3, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4>> WhenAnyValue<TSender, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Func<T1, T2, T3, T4, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5>> WhenAnyValue<TSender, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Func<T1, T2, T3, T4, T5, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Func<T1, T2, T3, T4, T5, T6, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6, T7>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Func<T1, T2, T3, T4, T5, T6, T7, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12>> property12, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TRet> selector) { }
     }
     public static class WhenAnyObservableMixin
     {
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs12)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs12)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Func<T1?, T2?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Func<T1?, T2?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Func<T1?, T2?, T3?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Func<T1?, T2?, T3?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Func<T1?, T2?, T3?, T4?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Func<T1?, T2?, T3?, T4?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Func<T1?, T2?, T3?, T4?, T5?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Func<T1?, T2?, T3?, T4?, T5?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T12>?>> obs12, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, T12?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T12>?>> obs12, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, T12?, TRet> selector)
             where TSender :  class { }
     }
 }
diff --git a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt
index 572e684b17..e0bd33e3de 100644
--- a/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt
+++ b/src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp3.1.approved.txt
@@ -394,27 +394,27 @@ namespace ReactiveUI
     }
     public static class OAPHCreationHelperMixin
     {
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, System.Linq.Expressions.Expression<System.Func<TObj, TRet?>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, System.Linq.Expressions.Expression<System.Func<TObj, TRet>> property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, TRet initialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
-        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj? source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
+        public static ReactiveUI.ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(this System.IObservable<TRet> target, TObj source, string property, out ReactiveUI.ObservableAsPropertyHelper<TRet> result, System.Func<TRet> getInitialValue, bool deferSubscription = false, System.Reactive.Concurrency.IScheduler? scheduler = null)
             where TObj :  class, ReactiveUI.IReactiveObject { }
     }
     public sealed class ObservableAsPropertyHelper<T> : ReactiveUI.IHandleObservableErrors, Splat.IEnableLogger, System.IDisposable
@@ -601,8 +601,8 @@ namespace ReactiveUI
     }
     public static class ReactiveNotifyPropertyChangedMixin
     {
-        public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> ObservableForProperty<TSender, TValue>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue?>> property, bool beforeChange = false, bool skipInitial = true) { }
-        public static System.IObservable<TRet> ObservableForProperty<TSender, TValue, TRet>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue?>> property, System.Func<TValue?, TRet> selector, bool beforeChange = false)
+        public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> ObservableForProperty<TSender, TValue>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue>> property, bool beforeChange = false, bool skipInitial = true) { }
+        public static System.IObservable<TRet> ObservableForProperty<TSender, TValue, TRet>(this TSender? item, System.Linq.Expressions.Expression<System.Func<TSender, TValue>> property, System.Func<TValue?, TRet> selector, bool beforeChange = false)
             where TSender :  class { }
         public static System.IObservable<ReactiveUI.IObservedChange<TSender, TValue>> SubscribeToExpressionChain<TSender, TValue>(this TSender? source, System.Linq.Expressions.Expression? expression, bool beforeChange = false, bool skipInitial = true, bool suppressWarnings = false) { }
     }
@@ -828,18 +828,18 @@ namespace ReactiveUI
     }
     public static class WhenAnyMixin
     {
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Func<ReactiveUI.IObservedChange<TSender, T1>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12?>> property12, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, ReactiveUI.IObservedChange<TSender, T12>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Func<ReactiveUI.IObservedChange<TSender, T1>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAny<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12>> property12, System.Func<ReactiveUI.IObservedChange<TSender, T1>, ReactiveUI.IObservedChange<TSender, T2>, ReactiveUI.IObservedChange<TSender, T3>, ReactiveUI.IObservedChange<TSender, T4>, ReactiveUI.IObservedChange<TSender, T5>, ReactiveUI.IObservedChange<TSender, T6>, ReactiveUI.IObservedChange<TSender, T7>, ReactiveUI.IObservedChange<TSender, T8>, ReactiveUI.IObservedChange<TSender, T9>, ReactiveUI.IObservedChange<TSender, T10>, ReactiveUI.IObservedChange<TSender, T11>, ReactiveUI.IObservedChange<TSender, T12>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
@@ -852,73 +852,73 @@ namespace ReactiveUI
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Linq.Expressions.Expression? property11, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
         public static System.IObservable<TRet> WhenAnyDynamic<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression? property1, System.Linq.Expressions.Expression? property2, System.Linq.Expressions.Expression? property3, System.Linq.Expressions.Expression? property4, System.Linq.Expressions.Expression? property5, System.Linq.Expressions.Expression? property6, System.Linq.Expressions.Expression? property7, System.Linq.Expressions.Expression? property8, System.Linq.Expressions.Expression? property9, System.Linq.Expressions.Expression? property10, System.Linq.Expressions.Expression? property11, System.Linq.Expressions.Expression? property12, System.Func<ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, ReactiveUI.IObservedChange<TSender?, object?>, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, TRet?>> property1) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Func<T1, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2>> WhenAnyValue<TSender, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Func<T1, T2, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3>> WhenAnyValue<TSender, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Func<T1, T2, T3, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4>> WhenAnyValue<TSender, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Func<T1, T2, T3, T4, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5>> WhenAnyValue<TSender, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Func<T1, T2, T3, T4, T5, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Func<T1, T2, T3, T4, T5, T6, TRet> selector) { }
-        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6, T7>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Func<T1, T2, T3, T4, T5, T6, T7, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TRet> selector) { }
-        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1?>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2?>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3?>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4?>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5?>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6?>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7?>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8?>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9?>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10?>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11?>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12?>> property12, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, TRet>> property1) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Func<T1, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2>> WhenAnyValue<TSender, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Func<T1, T2, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3>> WhenAnyValue<TSender, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Func<T1, T2, T3, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4>> WhenAnyValue<TSender, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Func<T1, T2, T3, T4, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5>> WhenAnyValue<TSender, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Func<T1, T2, T3, T4, T5, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Func<T1, T2, T3, T4, T5, T6, TRet> selector) { }
+        public static System.IObservable<System.ValueTuple<T1, T2, T3, T4, T5, T6, T7>> WhenAnyValue<TSender, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Func<T1, T2, T3, T4, T5, T6, T7, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, TRet> selector) { }
+        public static System.IObservable<TRet> WhenAnyValue<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, T1>> property1, System.Linq.Expressions.Expression<System.Func<TSender, T2>> property2, System.Linq.Expressions.Expression<System.Func<TSender, T3>> property3, System.Linq.Expressions.Expression<System.Func<TSender, T4>> property4, System.Linq.Expressions.Expression<System.Func<TSender, T5>> property5, System.Linq.Expressions.Expression<System.Func<TSender, T6>> property6, System.Linq.Expressions.Expression<System.Func<TSender, T7>> property7, System.Linq.Expressions.Expression<System.Func<TSender, T8>> property8, System.Linq.Expressions.Expression<System.Func<TSender, T9>> property9, System.Linq.Expressions.Expression<System.Func<TSender, T10>> property10, System.Linq.Expressions.Expression<System.Func<TSender, T11>> property11, System.Linq.Expressions.Expression<System.Func<TSender, T12>> property12, System.Func<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, TRet> selector) { }
     }
     public static class WhenAnyObservableMixin
     {
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs12)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<TRet>?>> obs12)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Func<T1?, T2?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Func<T1?, T2?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Func<T1?, T2?, T3?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Func<T1?, T2?, T3?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Func<T1?, T2?, T3?, T4?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Func<T1?, T2?, T3?, T4?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Func<T1?, T2?, T3?, T4?, T5?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Func<T1?, T2?, T3?, T4?, T5?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, TRet> selector)
             where TSender :  class { }
-        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender? sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T12>?>> obs12, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, T12?, TRet> selector)
+        public static System.IObservable<TRet> WhenAnyObservable<TSender, TRet, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12>(this TSender sender, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T1>?>> obs1, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T2>?>> obs2, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T3>?>> obs3, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T4>?>> obs4, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T5>?>> obs5, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T6>?>> obs6, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T7>?>> obs7, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T8>?>> obs8, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T9>?>> obs9, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T10>?>> obs10, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T11>?>> obs11, System.Linq.Expressions.Expression<System.Func<TSender, System.IObservable<T12>?>> obs12, System.Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, T12?, TRet> selector)
             where TSender :  class { }
     }
 }
diff --git a/src/ReactiveUI.Tests/Mocks/MockBindListView.cs b/src/ReactiveUI.Tests/Mocks/MockBindListView.cs
index 70cda838ff..8a9d7a0b60 100644
--- a/src/ReactiveUI.Tests/Mocks/MockBindListView.cs
+++ b/src/ReactiveUI.Tests/Mocks/MockBindListView.cs
@@ -55,7 +55,7 @@ public MockBindListView()
                     .Where(i => i != null)
                     .Cast<MockBindListItemViewModel>()
                     .Do(_ => ItemList.UnselectAll())
-                    .InvokeCommand(this, v => v.ViewModel!.SelectItem).DisposeWith(d);
+                    .InvokeCommand(this, v => v!.ViewModel!.SelectItem).DisposeWith(d);
             });
         }
 
diff --git a/src/ReactiveUI.Tests/ObservableAsPropertyHelper/ObservableAsPropertyHelperTest.cs b/src/ReactiveUI.Tests/ObservableAsPropertyHelper/ObservableAsPropertyHelperTest.cs
index f6d11b472a..29d9cc9a32 100644
--- a/src/ReactiveUI.Tests/ObservableAsPropertyHelper/ObservableAsPropertyHelperTest.cs
+++ b/src/ReactiveUI.Tests/ObservableAsPropertyHelper/ObservableAsPropertyHelperTest.cs
@@ -456,13 +456,13 @@ public void ToProperty_NameOf_ValidValuesProduced(string[] testWords, string[] f
 
             fixture.ObservableForProperty(x => x.LastThreeLettersOfOneWord, beforeChange: true).ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var lastThreeChanging).Subscribe();
 
-            var changing = new[] { firstThreeChanging, lastThreeChanging };
+            var changing = new[] { firstThreeChanging!, lastThreeChanging };
 
             fixture.ObservableForProperty(x => x.FirstThreeLettersOfOneWord, beforeChange: false).ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var firstThreeChanged).Subscribe();
 
             fixture.ObservableForProperty(x => x.LastThreeLettersOfOneWord, beforeChange: false).ToObservableChangeSet(ImmediateScheduler.Instance).Bind(out var lastThreeChanged).Subscribe();
 
-            var changed = new[] { firstThreeChanged, lastThreeChanged };
+            var changed = new[] { firstThreeChanged!, lastThreeChanged };
 
             Assert.True(changed.All(x => x.Count == 0));
             Assert.True(changing.All(x => x.Count == 0));
@@ -551,11 +551,11 @@ public void NullableTypesTestShouldntNeedDecorators2_ToProperty()
             fixture.WhenAnyValue(
                 x => x.ProjectService.ProjectsNullable,
                 x => x.AccountService.AccountUsersNullable)
-                   .Where(tuple => tuple.Item1.Any() && tuple.Item2.Any())
+                   .Where(tuple => tuple.Item1?.Count > 0 && tuple.Item2?.Count > 0)
                    .Select(tuple =>
                    {
                        var (projects, users) = tuple;
-                       return (int?)users.Values.Count(x => !string.IsNullOrWhiteSpace(x?.LastName));
+                       return users?.Values.Count(x => !string.IsNullOrWhiteSpace(x?.LastName));
                    })
                    .ToProperty(fixture, x => x.AccountsFound, out fixture._accountsFound);
 
diff --git a/src/ReactiveUI.Tests/Resolvers/DependencyResolverTests.cs b/src/ReactiveUI.Tests/Resolvers/DependencyResolverTests.cs
index 107192077e..9b8cfec912 100644
--- a/src/ReactiveUI.Tests/Resolvers/DependencyResolverTests.cs
+++ b/src/ReactiveUI.Tests/Resolvers/DependencyResolverTests.cs
@@ -145,13 +145,13 @@ private static Dictionary<Type, List<Type>> GetServicesThatShouldBeRegistered(IR
 
             new Registrations().Register((factory, serviceType) =>
             {
-                if (serviceTypeToImplementationTypes.TryGetValue(serviceType, out var implementationTypes) == false)
+                if (serviceTypeToImplementationTypes.TryGetValue(serviceType!, out var implementationTypes) == false)
                 {
                     implementationTypes = new List<Type>();
-                    serviceTypeToImplementationTypes.Add(serviceType, implementationTypes);
+                    serviceTypeToImplementationTypes.Add(serviceType!, implementationTypes);
                 }
 
-                implementationTypes.Add(factory().GetType());
+                implementationTypes.Add(factory()!.GetType());
             });
 
             new PlatformRegistrations().Register((factory, serviceType) =>
diff --git a/src/ReactiveUI.Tests/WhenAny/Mockups/HostTestFixture.cs b/src/ReactiveUI.Tests/WhenAny/Mockups/HostTestFixture.cs
index 4ca394fd54..5e33e0f3dc 100644
--- a/src/ReactiveUI.Tests/WhenAny/Mockups/HostTestFixture.cs
+++ b/src/ReactiveUI.Tests/WhenAny/Mockups/HostTestFixture.cs
@@ -3,6 +3,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
+using System.Reactive.Linq;
+
 namespace ReactiveUI.Tests
 {
     /// <summary>
@@ -10,12 +12,41 @@ namespace ReactiveUI.Tests
     /// </summary>
     public class HostTestFixture : ReactiveObject
     {
+        private readonly ObservableAsPropertyHelper<string?> _ownerName;
         private TestFixture? _Child;
-
+        private OwnerClass? _owner;
         private NonObservableTestFixture? _PocoChild;
-
         private int _SomeOtherParam;
 
+        public HostTestFixture()
+        {
+            _ownerName = this.WhenAnyValue(x => x.Owner)
+              .WhereNotNull()
+              .Select(owner => owner.WhenAnyValue(x => x.Name))
+              .Switch()
+              .ToProperty(this, x => x.OwnerName);
+        }
+
+        /// <summary>
+        /// Gets the name of the owner.
+        /// </summary>
+        /// <value>
+        /// The name of the owner.
+        /// </value>
+        public string? OwnerName => _ownerName.Value;
+
+        /// <summary>
+        /// Gets or sets the owner.
+        /// </summary>
+        /// <value>
+        /// The owner.
+        /// </value>
+        public OwnerClass? Owner
+        {
+            get => _owner;
+            set => this.RaiseAndSetIfChanged(ref _owner, value);
+        }
+
         /// <summary>
         /// Gets or sets the child.
         /// </summary>
diff --git a/src/ReactiveUI.Tests/WhenAny/Mockups/OwnerClass.cs b/src/ReactiveUI.Tests/WhenAny/Mockups/OwnerClass.cs
new file mode 100644
index 0000000000..a5c9671253
--- /dev/null
+++ b/src/ReactiveUI.Tests/WhenAny/Mockups/OwnerClass.cs
@@ -0,0 +1,28 @@
+// Copyright (c) 2021 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+namespace ReactiveUI.Tests
+{
+    /// <summary>
+    /// Owner Class.
+    /// </summary>
+    /// <seealso cref="ReactiveUI.ReactiveObject" />
+    public class OwnerClass : ReactiveObject
+    {
+        private string? _name;
+
+        /// <summary>
+        /// Gets or sets the name.
+        /// </summary>
+        /// <value>
+        /// The name.
+        /// </value>
+        public string? Name
+        {
+            get => _name;
+            set => this.RaiseAndSetIfChanged(ref _name, value);
+        }
+    }
+}
diff --git a/src/ReactiveUI.Tests/WhenAny/ReactiveNotifyPropertyChangedMixinTest.cs b/src/ReactiveUI.Tests/WhenAny/ReactiveNotifyPropertyChangedMixinTest.cs
index 75f267be34..0972cf81ff 100644
--- a/src/ReactiveUI.Tests/WhenAny/ReactiveNotifyPropertyChangedMixinTest.cs
+++ b/src/ReactiveUI.Tests/WhenAny/ReactiveNotifyPropertyChangedMixinTest.cs
@@ -636,9 +636,9 @@ public void WhenAnyValueShouldWorkEvenWithNormalProperties()
             };
 
             var output1 = new List<string?>();
-            var output2 = new List<int>();
+            var output2 = new List<int?>();
             fixture.WhenAnyValue(x => x.PocoProperty).Subscribe(output1.Add);
-            fixture.WhenAnyValue(x => x.IsOnlyOneWord, x => x.Length).Subscribe(output2.Add);
+            fixture.WhenAnyValue(x => x.IsOnlyOneWord, x => x?.Length).Subscribe(output2.Add);
 
             Assert.Equal(1, output1.Count);
             Assert.Equal("Bamf", output1[0]);
@@ -784,11 +784,11 @@ public void NullableTypesTestShouldntNeedDecorators2()
             fixture.WhenAnyValue(
                 x => x.ProjectService.ProjectsNullable,
                 x => x.AccountService.AccountUsersNullable)
-                   .Where(tuple => tuple.Item1.Any() && tuple.Item2.Any())
+                   .Where(tuple => tuple.Item1?.Count > 0 && tuple.Item2?.Count > 0)
                    .Select(tuple =>
                    {
                        var (projects, users) = tuple;
-                       return users.Values.Where(x => !string.IsNullOrWhiteSpace(x?.LastName));
+                       return users?.Values.Where(x => !string.IsNullOrWhiteSpace(x?.LastName));
                    })
                    .Subscribe(dict => result = dict);
 
@@ -804,7 +804,7 @@ public void NonNullableTypesTestShouldntNeedDecorators()
             WhenAnyTestFixture fixture = new();
             IEnumerable<AccountUser>? result = null;
             fixture.WhenAnyValue(x => x.AccountService.AccountUsers)
-                   .Where(users => users.Any())
+                   .Where(users => users.Count > 0)
                    .Select(users => users.Values.Where(x => !string.IsNullOrWhiteSpace(x.LastName)))
                    .Subscribe(dict => result = dict);
 
@@ -818,15 +818,15 @@ public void NonNullableTypesTestShouldntNeedDecorators()
         public void NonNullableTypesTestShouldntNeedDecorators2()
         {
             WhenAnyTestFixture fixture = new();
-            IEnumerable<AccountUser?>? result = null;
+            IEnumerable<AccountUser>? result = null;
             fixture.WhenAnyValue(
                 x => x.ProjectService.Projects,
                 x => x.AccountService.AccountUsers)
-                   .Where(tuple => tuple.Item1.Any() && tuple.Item2.Any())
+                   .Where(tuple => tuple.Item1?.Count > 0 && tuple.Item2?.Count > 0)
                    .Select(tuple =>
                    {
                        var (projects, users) = tuple;
-                       return users.Values.Where(x => !string.IsNullOrWhiteSpace(x?.LastName));
+                       return users!.Values.Where(x => !string.IsNullOrWhiteSpace(x.LastName));
                    })
                    .Subscribe(dict => result = dict);
 
@@ -842,16 +842,52 @@ public void WhenAnyValueWith1Paramerters()
             WhenAnyTestFixture fixture = new();
             string? result = null;
             fixture.WhenAnyValue(
-                x => x.Value1)
-                   .Select(value =>
-                   {
-                       return value;
-                   })
-                   .Subscribe(value => result = value);
+                x => x.Value1).Subscribe(value => result = value);
 
             Assert.Equal(result, "1");
         }
 
+        [Fact]
+        public void WhenAnyValueWith1ParamertersSequentialCheck()
+        {
+            WhenAnyTestFixture fixture = new();
+            var result = string.Empty;
+            fixture.Value1 = null!;
+            fixture.WhenAnyValue(
+                x => x.Value1).Subscribe(value => result = value);
+
+            Assert.Equal(result, null);
+
+            fixture.Value1 = "A";
+            Assert.Equal(result, "A");
+
+            fixture.Value1 = "B";
+            Assert.Equal(result, "B");
+
+            fixture.Value1 = null!;
+            Assert.Equal(result, null);
+        }
+
+        [Fact]
+        public void WhenAnyValueWith1ParamertersSequentialCheckNullable()
+        {
+            WhenAnyTestFixture fixture = new();
+            var result = string.Empty;
+            fixture.WhenAnyValue(
+                x => x.Value2).Subscribe(value => result = value);
+
+            Assert.Equal(result, null);
+
+            fixture.Value2 = "A";
+            Assert.Equal(result, "A");
+
+            fixture.Value2 = "B";
+            Assert.Equal(result, "B");
+
+            fixture.Value2 = null;
+            Assert.Equal(result, null);
+        }
+
         /// <summary>
         /// Whens any value with2 paramerters returns tuple.
         /// </summary>
@@ -1289,5 +1325,31 @@ public void WhenAnyValueWith12ParamertersReturnsValues()
 
             Assert.Equal(result, "1357911");
         }
+
+        [Fact]
+        public void WhenAnyValueWithToProperty()
+        {
+            HostTestFixture? fixture = new();
+
+            Assert.Equal(null, fixture.Owner);
+            Assert.Equal(null, fixture.OwnerName);
+
+            fixture.Owner = new();
+            fixture.Owner.Name = "Fred";
+            Assert.NotNull(fixture.Owner);
+            Assert.Equal("Fred", fixture.OwnerName);
+
+            fixture.Owner.Name = "Wilma";
+            Assert.Equal("Wilma", fixture.OwnerName);
+
+            fixture.Owner.Name = null;
+            Assert.Equal(null, fixture.OwnerName);
+
+            fixture.Owner.Name = "Barney";
+            Assert.Equal("Barney", fixture.OwnerName);
+
+            fixture.Owner.Name = "Betty";
+            Assert.Equal("Betty", fixture.OwnerName);
+        }
     }
 }
diff --git a/src/ReactiveUI/Mixins/ReactiveNotifyPropertyChangedMixin.cs b/src/ReactiveUI/Mixins/ReactiveNotifyPropertyChangedMixin.cs
index bbc449e767..3d3f4b2d6a 100644
--- a/src/ReactiveUI/Mixins/ReactiveNotifyPropertyChangedMixin.cs
+++ b/src/ReactiveUI/Mixins/ReactiveNotifyPropertyChangedMixin.cs
@@ -49,15 +49,10 @@ public static class ReactiveNotifyPropertyChangedMixin
         /// notifications for the given property.</returns>
         public static IObservable<IObservedChange<TSender, TValue>> ObservableForProperty<TSender, TValue>(
                 this TSender? item,
-                Expression<Func<TSender, TValue?>> property,
+                Expression<Func<TSender, TValue>> property,
                 bool beforeChange = false,
                 bool skipInitial = true)
         {
-            if (item is null)
-            {
-                throw new ArgumentNullException(nameof(item));
-            }
-
             if (property is null)
             {
                 throw new ArgumentNullException(nameof(property));
@@ -105,7 +100,7 @@ public static IObservable<IObservedChange<TSender, TValue>> ObservableForPropert
         /// notifications for the given property.</returns>
         public static IObservable<TRet> ObservableForProperty<TSender, TValue, TRet>(
                 this TSender? item,
-                Expression<Func<TSender, TValue?>> property,
+                Expression<Func<TSender, TValue>> property,
                 Func<TValue?, TRet> selector,
                 bool beforeChange = false) // TODO: Create Test
             where TSender : class
@@ -139,13 +134,8 @@ public static IObservable<IObservedChange<TSender, TValue>> SubscribeToExpressio
             bool skipInitial = true,
             bool suppressWarnings = false) // TODO: Create Test
         {
-            if (source is null)
-            {
-                throw new ArgumentNullException(nameof(source));
-            }
-
             IObservable<IObservedChange<object?, object?>> notifier =
-                Observable.Return(new ObservedChange<object?, object?>(null, null!, source));
+                Observable.Return(new ObservedChange<object?, object?>(null, null, source));
 
             var chain = Reflection.Rewrite(expression).GetExpressionChain();
             notifier = chain.Aggregate(notifier, (n, expr) => n
@@ -168,7 +158,7 @@ public static IObservable<IObservedChange<TSender, TValue>> SubscribeToExpressio
                     throw new InvalidCastException($"Unable to cast from {val.GetType()} to {typeof(TValue)}.");
                 }
 
-                return new ObservedChange<TSender, TValue>(source, expression, (TValue)val!);
+                return new ObservedChange<TSender, TValue>(source!, expression, (TValue)val!);
             });
 
             return r.DistinctUntilChanged(x => x.Value);
diff --git a/src/ReactiveUI/ObservableForProperty/OAPHCreationHelperMixin.cs b/src/ReactiveUI/ObservableForProperty/OAPHCreationHelperMixin.cs
index a93e5f3b24..f2a769ec72 100644
--- a/src/ReactiveUI/ObservableForProperty/OAPHCreationHelperMixin.cs
+++ b/src/ReactiveUI/ObservableForProperty/OAPHCreationHelperMixin.cs
@@ -46,8 +46,8 @@ public static class OAPHCreationHelperMixin
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             bool deferSubscription = false,
             IScheduler? scheduler = null) // TODO: Create Test
             where TObj : class, IReactiveObject
@@ -105,8 +105,8 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             TRet initialValue,
             bool deferSubscription = false,
             IScheduler? scheduler = null) // TODO: Create Test
@@ -148,8 +148,8 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             Func<TRet> getInitialValue,
             bool deferSubscription = false,
             IScheduler? scheduler = null) // TODO: Create Test
@@ -190,8 +190,8 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             out ObservableAsPropertyHelper<TRet> result,
             bool deferSubscription = false,
             IScheduler? scheduler = null) // TODO: Create Test
@@ -257,8 +257,8 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             out ObservableAsPropertyHelper<TRet> result,
             TRet initialValue,
             bool deferSubscription = false,
@@ -304,8 +304,8 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
-            Expression<Func<TObj, TRet?>> property,
+            TObj source,
+            Expression<Func<TObj, TRet>> property,
             out ObservableAsPropertyHelper<TRet> result,
             Func<TRet> getInitialValue,
             bool deferSubscription = false,
@@ -354,7 +354,7 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
+            TObj source,
             string property,
             TRet initialValue,
             bool deferSubscription = false,
@@ -395,7 +395,7 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
+            TObj source,
             string property,
             bool deferSubscription = false,
             IScheduler? scheduler = null) // TODO: Create Test
@@ -455,7 +455,7 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
+            TObj source,
             string property,
             Func<TRet> getInitialValue,
             bool deferSubscription = false,
@@ -515,7 +515,7 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
+            TObj source,
             string property,
             out ObservableAsPropertyHelper<TRet> result,
             bool deferSubscription = false,
@@ -584,7 +584,7 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         /// </returns>
         public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
             this IObservable<TRet> target,
-            TObj? source,
+            TObj source,
             string property,
             out ObservableAsPropertyHelper<TRet> result,
             Func<TRet> getInitialValue,
@@ -618,9 +618,9 @@ public static ObservableAsPropertyHelper<TRet> ToProperty<TObj, TRet>(
         }
 
         private static ObservableAsPropertyHelper<TRet> ObservableToProperty<TObj, TRet>(
-            this TObj? target,
+            this TObj target,
             IObservable<TRet?> observable,
-            Expression<Func<TObj, TRet?>> property,
+            Expression<Func<TObj, TRet>> property,
             Func<TRet> getInitialValue,
             bool deferSubscription = false,
             IScheduler? scheduler = null)
@@ -678,9 +678,9 @@ private static ObservableAsPropertyHelper<TRet> ObservableToProperty<TObj, TRet>
         }
 
         private static ObservableAsPropertyHelper<TRet> ObservableToProperty<TObj, TRet>(
-            this TObj? target,
+            this TObj target,
             IObservable<TRet?> observable,
-            Expression<Func<TObj, TRet?>> property,
+            Expression<Func<TObj, TRet>> property,
             bool deferSubscription = false,
             IScheduler? scheduler = null)
                 where TObj : class, IReactiveObject
@@ -737,7 +737,7 @@ private static ObservableAsPropertyHelper<TRet> ObservableToProperty<TObj, TRet>
         }
 
         private static ObservableAsPropertyHelper<TRet> ObservableToProperty<TObj, TRet>(
-            this TObj? target,
+            this TObj target,
             IObservable<TRet?> observable,
             string property,
             Func<TRet> getInitialValue,
@@ -770,7 +770,7 @@ private static ObservableAsPropertyHelper<TRet> ObservableToProperty<TObj, TRet>
         }
 
         private static ObservableAsPropertyHelper<TRet> ObservableToProperty<TObj, TRet>(
-            this TObj? target,
+            this TObj target,
             IObservable<TRet?> observable,
             string property,
             bool deferSubscription = false,
diff --git a/src/ReactiveUI/Platforms/uikit-common/RoutedViewHost.cs b/src/ReactiveUI/Platforms/uikit-common/RoutedViewHost.cs
index b1943d8be1..afbf126e39 100644
--- a/src/ReactiveUI/Platforms/uikit-common/RoutedViewHost.cs
+++ b/src/ReactiveUI/Platforms/uikit-common/RoutedViewHost.cs
@@ -59,8 +59,11 @@ public RoutedViewHost()
 
                                 if (view is not null)
                                 {
-                                    _titleUpdater.Disposable = Router.GetCurrentViewModel()
-                                        .WhenAnyValue(y => y.UrlPathSegment)
+                                    _titleUpdater.Disposable = Router
+                                        .WhenAnyValue(y => y.GetCurrentViewModel())
+                                        .WhereNotNull()
+                                        .Select(vm => vm.WhenAnyValue(x => x.UrlPathSegment))
+                                        .Switch()
                                         .Subscribe(y => view.NavigationItem.Title = y);
                                 }
                             }
@@ -85,9 +88,12 @@ public RoutedViewHost()
 
                             if (x?.View is not null)
                             {
-                                _titleUpdater.Disposable = Router.GetCurrentViewModel()
-                                    .WhenAnyValue(y => y.UrlPathSegment)
-                                    .Subscribe(y => x.View.NavigationItem.Title = y);
+                                _titleUpdater.Disposable = Router
+                                        .WhenAnyValue(y => y.GetCurrentViewModel())
+                                        .WhereNotNull()
+                                        .Select(vm => vm.WhenAnyValue(x => x.UrlPathSegment))
+                                        .Switch()
+                                        .Subscribe(y => x.View.NavigationItem.Title = y);
                             }
 
                             _routerInstigated = true;
diff --git a/src/ReactiveUI/VariadicTemplates.cs b/src/ReactiveUI/VariadicTemplates.cs
index 907d1dc1a6..0a8fdfa05f 100644
--- a/src/ReactiveUI/VariadicTemplates.cs
+++ b/src/ReactiveUI/VariadicTemplates.cs
@@ -35,9 +35,9 @@ public static class WhenAnyMixin
         /// <param name="property1">The first property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet>(
             this TSender? sender,
-            Expression<Func<TSender, TRet?>> property1)
+            Expression<Func<TSender, TRet>> property1)
         {
-            return sender.WhenAny(property1, (IObservedChange<TSender, TRet> c1) => c1.Value);
+            return sender!.WhenAny(property1, (IObservedChange<TSender, TRet> c1) => c1.Value);
         }
 
                                                                         
@@ -54,10 +54,10 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
+                        Expression<Func<TSender, T1>> property1,
                         Func<T1, TRet> selector)
         {
-            return sender.WhenAny(property1,
+            return sender!.WhenAny(property1,
                                 (c1) =>
                                     selector(c1.Value));
         }
@@ -74,10 +74,10 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
+                            Expression<Func<TSender, T1>> property1,
                             Func<IObservedChange<TSender, T1>, TRet> selector)
         {
-                            return sender.ObservableForProperty(property1, false, false).Select(selector);
+                            return sender!.ObservableForProperty(property1, false, false).Select(selector);
                     }
 
 
@@ -112,11 +112,11 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="property2">The 2 property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<(T1,T2)> WhenAnyValue<TSender, T1,T2>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2
             )
         {
-            return sender.WhenAny(property1, property2,
+            return sender!.WhenAny(property1, property2,
                                 (c1, c2) =>
                                     (c1.Value, c2.Value));
         }
@@ -134,11 +134,11 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
                         Func<T1,T2, TRet> selector)
         {
-            return sender.WhenAny(property1, property2,
+            return sender!.WhenAny(property1, property2,
                                 (c1, c2) =>
                                     selector(c1.Value, c2.Value));
         }
@@ -156,13 +156,13 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
                                 selector
             );
                     }
@@ -207,12 +207,12 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="property3">The 3 property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<(T1,T2,T3)> WhenAnyValue<TSender, T1,T2,T3>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3
             )
         {
-            return sender.WhenAny(property1, property2, property3,
+            return sender!.WhenAny(property1, property2, property3,
                                 (c1, c2, c3) =>
                                     (c1.Value, c2.Value, c3.Value));
         }
@@ -231,12 +231,12 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
                         Func<T1,T2,T3, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3,
+            return sender!.WhenAny(property1, property2, property3,
                                 (c1, c2, c3) =>
                                     selector(c1.Value, c2.Value, c3.Value));
         }
@@ -255,15 +255,15 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
                                 selector
             );
                     }
@@ -313,13 +313,13 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="property4">The 4 property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<(T1,T2,T3,T4)> WhenAnyValue<TSender, T1,T2,T3,T4>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4
             )
         {
-            return sender.WhenAny(property1, property2, property3, property4,
+            return sender!.WhenAny(property1, property2, property3, property4,
                                 (c1, c2, c3, c4) =>
                                     (c1.Value, c2.Value, c3.Value, c4.Value));
         }
@@ -339,13 +339,13 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
                         Func<T1,T2,T3,T4, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4,
+            return sender!.WhenAny(property1, property2, property3, property4,
                                 (c1, c2, c3, c4) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value));
         }
@@ -365,17 +365,17 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
                                 selector
             );
                     }
@@ -430,14 +430,14 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="property5">The 5 property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<(T1,T2,T3,T4,T5)> WhenAnyValue<TSender, T1,T2,T3,T4,T5>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5
             )
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5,
+            return sender!.WhenAny(property1, property2, property3, property4, property5,
                                 (c1, c2, c3, c4, c5) =>
                                     (c1.Value, c2.Value, c3.Value, c4.Value, c5.Value));
         }
@@ -458,14 +458,14 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
                         Func<T1,T2,T3,T4,T5, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5,
+            return sender!.WhenAny(property1, property2, property3, property4, property5,
                                 (c1, c2, c3, c4, c5) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value));
         }
@@ -486,19 +486,19 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
                                 selector
             );
                     }
@@ -558,15 +558,15 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="property6">The 6 property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<(T1,T2,T3,T4,T5,T6)> WhenAnyValue<TSender, T1,T2,T3,T4,T5,T6>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6
             )
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6,
                                 (c1, c2, c3, c4, c5, c6) =>
                                     (c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value));
         }
@@ -588,15 +588,15 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
                         Func<T1,T2,T3,T4,T5,T6, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6,
                                 (c1, c2, c3, c4, c5, c6) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value));
         }
@@ -618,21 +618,21 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5,T6>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
-                            Expression<Func<TSender, T6?>> property6,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
+                            Expression<Func<TSender, T6>> property6,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, IObservedChange<TSender, T6>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
-                                    sender.ObservableForProperty(property6, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property6, false, false),
                                 selector
             );
                     }
@@ -697,16 +697,16 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="property7">The 7 property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<(T1,T2,T3,T4,T5,T6,T7)> WhenAnyValue<TSender, T1,T2,T3,T4,T5,T6,T7>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
-                        Expression<Func<TSender, T7?>> property7
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
+                        Expression<Func<TSender, T7>> property7
             )
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6, property7,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6, property7,
                                 (c1, c2, c3, c4, c5, c6, c7) =>
                                     (c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value, c7.Value));
         }
@@ -729,16 +729,16 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
-                        Expression<Func<TSender, T7?>> property7,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
+                        Expression<Func<TSender, T7>> property7,
                         Func<T1,T2,T3,T4,T5,T6,T7, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6, property7,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6, property7,
                                 (c1, c2, c3, c4, c5, c6, c7) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value, c7.Value));
         }
@@ -761,23 +761,23 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5,T6,T7>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
-                            Expression<Func<TSender, T6?>> property6,
-                            Expression<Func<TSender, T7?>> property7,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
+                            Expression<Func<TSender, T6>> property6,
+                            Expression<Func<TSender, T7>> property7,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, IObservedChange<TSender, T6>, IObservedChange<TSender, T7>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
-                                    sender.ObservableForProperty(property6, false, false),
-                                    sender.ObservableForProperty(property7, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property6, false, false),
+                                    sender!.ObservableForProperty(property7, false, false),
                                 selector
             );
                     }
@@ -849,17 +849,17 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
-                        Expression<Func<TSender, T7?>> property7,
-                        Expression<Func<TSender, T8?>> property8,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
+                        Expression<Func<TSender, T7>> property7,
+                        Expression<Func<TSender, T8>> property8,
                         Func<T1,T2,T3,T4,T5,T6,T7,T8, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8,
                                 (c1, c2, c3, c4, c5, c6, c7, c8) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value, c7.Value, c8.Value));
         }
@@ -883,25 +883,25 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
-                            Expression<Func<TSender, T6?>> property6,
-                            Expression<Func<TSender, T7?>> property7,
-                            Expression<Func<TSender, T8?>> property8,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
+                            Expression<Func<TSender, T6>> property6,
+                            Expression<Func<TSender, T7>> property7,
+                            Expression<Func<TSender, T8>> property8,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, IObservedChange<TSender, T6>, IObservedChange<TSender, T7>, IObservedChange<TSender, T8>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
-                                    sender.ObservableForProperty(property6, false, false),
-                                    sender.ObservableForProperty(property7, false, false),
-                                    sender.ObservableForProperty(property8, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property6, false, false),
+                                    sender!.ObservableForProperty(property7, false, false),
+                                    sender!.ObservableForProperty(property8, false, false),
                                 selector
             );
                     }
@@ -978,18 +978,18 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
-                        Expression<Func<TSender, T7?>> property7,
-                        Expression<Func<TSender, T8?>> property8,
-                        Expression<Func<TSender, T9?>> property9,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
+                        Expression<Func<TSender, T7>> property7,
+                        Expression<Func<TSender, T8>> property8,
+                        Expression<Func<TSender, T9>> property9,
                         Func<T1,T2,T3,T4,T5,T6,T7,T8,T9, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9,
                                 (c1, c2, c3, c4, c5, c6, c7, c8, c9) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value, c7.Value, c8.Value, c9.Value));
         }
@@ -1014,27 +1014,27 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
-                            Expression<Func<TSender, T6?>> property6,
-                            Expression<Func<TSender, T7?>> property7,
-                            Expression<Func<TSender, T8?>> property8,
-                            Expression<Func<TSender, T9?>> property9,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
+                            Expression<Func<TSender, T6>> property6,
+                            Expression<Func<TSender, T7>> property7,
+                            Expression<Func<TSender, T8>> property8,
+                            Expression<Func<TSender, T9>> property9,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, IObservedChange<TSender, T6>, IObservedChange<TSender, T7>, IObservedChange<TSender, T8>, IObservedChange<TSender, T9>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
-                                    sender.ObservableForProperty(property6, false, false),
-                                    sender.ObservableForProperty(property7, false, false),
-                                    sender.ObservableForProperty(property8, false, false),
-                                    sender.ObservableForProperty(property9, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property6, false, false),
+                                    sender!.ObservableForProperty(property7, false, false),
+                                    sender!.ObservableForProperty(property8, false, false),
+                                    sender!.ObservableForProperty(property9, false, false),
                                 selector
             );
                     }
@@ -1116,19 +1116,19 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
-                        Expression<Func<TSender, T7?>> property7,
-                        Expression<Func<TSender, T8?>> property8,
-                        Expression<Func<TSender, T9?>> property9,
-                        Expression<Func<TSender, T10?>> property10,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
+                        Expression<Func<TSender, T7>> property7,
+                        Expression<Func<TSender, T8>> property8,
+                        Expression<Func<TSender, T9>> property9,
+                        Expression<Func<TSender, T10>> property10,
                         Func<T1,T2,T3,T4,T5,T6,T7,T8,T9,T10, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9, property10,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9, property10,
                                 (c1, c2, c3, c4, c5, c6, c7, c8, c9, c10) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value, c7.Value, c8.Value, c9.Value, c10.Value));
         }
@@ -1154,29 +1154,29 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
-                            Expression<Func<TSender, T6?>> property6,
-                            Expression<Func<TSender, T7?>> property7,
-                            Expression<Func<TSender, T8?>> property8,
-                            Expression<Func<TSender, T9?>> property9,
-                            Expression<Func<TSender, T10?>> property10,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
+                            Expression<Func<TSender, T6>> property6,
+                            Expression<Func<TSender, T7>> property7,
+                            Expression<Func<TSender, T8>> property8,
+                            Expression<Func<TSender, T9>> property9,
+                            Expression<Func<TSender, T10>> property10,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, IObservedChange<TSender, T6>, IObservedChange<TSender, T7>, IObservedChange<TSender, T8>, IObservedChange<TSender, T9>, IObservedChange<TSender, T10>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
-                                    sender.ObservableForProperty(property6, false, false),
-                                    sender.ObservableForProperty(property7, false, false),
-                                    sender.ObservableForProperty(property8, false, false),
-                                    sender.ObservableForProperty(property9, false, false),
-                                    sender.ObservableForProperty(property10, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property6, false, false),
+                                    sender!.ObservableForProperty(property7, false, false),
+                                    sender!.ObservableForProperty(property8, false, false),
+                                    sender!.ObservableForProperty(property9, false, false),
+                                    sender!.ObservableForProperty(property10, false, false),
                                 selector
             );
                     }
@@ -1263,20 +1263,20 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
-                        Expression<Func<TSender, T7?>> property7,
-                        Expression<Func<TSender, T8?>> property8,
-                        Expression<Func<TSender, T9?>> property9,
-                        Expression<Func<TSender, T10?>> property10,
-                        Expression<Func<TSender, T11?>> property11,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
+                        Expression<Func<TSender, T7>> property7,
+                        Expression<Func<TSender, T8>> property8,
+                        Expression<Func<TSender, T9>> property9,
+                        Expression<Func<TSender, T10>> property10,
+                        Expression<Func<TSender, T11>> property11,
                         Func<T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9, property10, property11,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9, property10, property11,
                                 (c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value, c7.Value, c8.Value, c9.Value, c10.Value, c11.Value));
         }
@@ -1303,31 +1303,31 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
-                            Expression<Func<TSender, T6?>> property6,
-                            Expression<Func<TSender, T7?>> property7,
-                            Expression<Func<TSender, T8?>> property8,
-                            Expression<Func<TSender, T9?>> property9,
-                            Expression<Func<TSender, T10?>> property10,
-                            Expression<Func<TSender, T11?>> property11,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
+                            Expression<Func<TSender, T6>> property6,
+                            Expression<Func<TSender, T7>> property7,
+                            Expression<Func<TSender, T8>> property8,
+                            Expression<Func<TSender, T9>> property9,
+                            Expression<Func<TSender, T10>> property10,
+                            Expression<Func<TSender, T11>> property11,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, IObservedChange<TSender, T6>, IObservedChange<TSender, T7>, IObservedChange<TSender, T8>, IObservedChange<TSender, T9>, IObservedChange<TSender, T10>, IObservedChange<TSender, T11>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
-                                    sender.ObservableForProperty(property6, false, false),
-                                    sender.ObservableForProperty(property7, false, false),
-                                    sender.ObservableForProperty(property8, false, false),
-                                    sender.ObservableForProperty(property9, false, false),
-                                    sender.ObservableForProperty(property10, false, false),
-                                    sender.ObservableForProperty(property11, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property6, false, false),
+                                    sender!.ObservableForProperty(property7, false, false),
+                                    sender!.ObservableForProperty(property8, false, false),
+                                    sender!.ObservableForProperty(property9, false, false),
+                                    sender!.ObservableForProperty(property10, false, false),
+                                    sender!.ObservableForProperty(property11, false, false),
                                 selector
             );
                     }
@@ -1419,21 +1419,21 @@ public static IObservable<TRet> WhenAnyDynamic<TSender, TRet>(
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12>(
             this TSender? sender,
-                        Expression<Func<TSender, T1?>> property1,
-                        Expression<Func<TSender, T2?>> property2,
-                        Expression<Func<TSender, T3?>> property3,
-                        Expression<Func<TSender, T4?>> property4,
-                        Expression<Func<TSender, T5?>> property5,
-                        Expression<Func<TSender, T6?>> property6,
-                        Expression<Func<TSender, T7?>> property7,
-                        Expression<Func<TSender, T8?>> property8,
-                        Expression<Func<TSender, T9?>> property9,
-                        Expression<Func<TSender, T10?>> property10,
-                        Expression<Func<TSender, T11?>> property11,
-                        Expression<Func<TSender, T12?>> property12,
+                        Expression<Func<TSender, T1>> property1,
+                        Expression<Func<TSender, T2>> property2,
+                        Expression<Func<TSender, T3>> property3,
+                        Expression<Func<TSender, T4>> property4,
+                        Expression<Func<TSender, T5>> property5,
+                        Expression<Func<TSender, T6>> property6,
+                        Expression<Func<TSender, T7>> property7,
+                        Expression<Func<TSender, T8>> property8,
+                        Expression<Func<TSender, T9>> property9,
+                        Expression<Func<TSender, T10>> property10,
+                        Expression<Func<TSender, T11>> property11,
+                        Expression<Func<TSender, T12>> property12,
                         Func<T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12, TRet> selector)
         {
-            return sender.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9, property10, property11, property12,
+            return sender!.WhenAny(property1, property2, property3, property4, property5, property6, property7, property8, property9, property10, property11, property12,
                                 (c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12) =>
                                     selector(c1.Value, c2.Value, c3.Value, c4.Value, c5.Value, c6.Value, c7.Value, c8.Value, c9.Value, c10.Value, c11.Value, c12.Value));
         }
@@ -1461,33 +1461,33 @@ public static IObservable<TRet> WhenAnyValue<TSender, TRet, T1,T2,T3,T4,T5,T6,T7
         /// <param name="selector">The selector which will determine the final value from the properties.</param>
         public static IObservable<TRet> WhenAny<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12>(
                 this TSender? sender,
-                            Expression<Func<TSender, T1?>> property1,
-                            Expression<Func<TSender, T2?>> property2,
-                            Expression<Func<TSender, T3?>> property3,
-                            Expression<Func<TSender, T4?>> property4,
-                            Expression<Func<TSender, T5?>> property5,
-                            Expression<Func<TSender, T6?>> property6,
-                            Expression<Func<TSender, T7?>> property7,
-                            Expression<Func<TSender, T8?>> property8,
-                            Expression<Func<TSender, T9?>> property9,
-                            Expression<Func<TSender, T10?>> property10,
-                            Expression<Func<TSender, T11?>> property11,
-                            Expression<Func<TSender, T12?>> property12,
+                            Expression<Func<TSender, T1>> property1,
+                            Expression<Func<TSender, T2>> property2,
+                            Expression<Func<TSender, T3>> property3,
+                            Expression<Func<TSender, T4>> property4,
+                            Expression<Func<TSender, T5>> property5,
+                            Expression<Func<TSender, T6>> property6,
+                            Expression<Func<TSender, T7>> property7,
+                            Expression<Func<TSender, T8>> property8,
+                            Expression<Func<TSender, T9>> property9,
+                            Expression<Func<TSender, T10>> property10,
+                            Expression<Func<TSender, T11>> property11,
+                            Expression<Func<TSender, T12>> property12,
                             Func<IObservedChange<TSender, T1>, IObservedChange<TSender, T2>, IObservedChange<TSender, T3>, IObservedChange<TSender, T4>, IObservedChange<TSender, T5>, IObservedChange<TSender, T6>, IObservedChange<TSender, T7>, IObservedChange<TSender, T8>, IObservedChange<TSender, T9>, IObservedChange<TSender, T10>, IObservedChange<TSender, T11>, IObservedChange<TSender, T12>, TRet> selector)
         {
                         return Observable.CombineLatest(
-                                    sender.ObservableForProperty(property1, false, false),
-                                    sender.ObservableForProperty(property2, false, false),
-                                    sender.ObservableForProperty(property3, false, false),
-                                    sender.ObservableForProperty(property4, false, false),
-                                    sender.ObservableForProperty(property5, false, false),
-                                    sender.ObservableForProperty(property6, false, false),
-                                    sender.ObservableForProperty(property7, false, false),
-                                    sender.ObservableForProperty(property8, false, false),
-                                    sender.ObservableForProperty(property9, false, false),
-                                    sender.ObservableForProperty(property10, false, false),
-                                    sender.ObservableForProperty(property11, false, false),
-                                    sender.ObservableForProperty(property12, false, false),
+                                    sender!.ObservableForProperty(property1, false, false),
+                                    sender!.ObservableForProperty(property2, false, false),
+                                    sender!.ObservableForProperty(property3, false, false),
+                                    sender!.ObservableForProperty(property4, false, false),
+                                    sender!.ObservableForProperty(property5, false, false),
+                                    sender!.ObservableForProperty(property6, false, false),
+                                    sender!.ObservableForProperty(property7, false, false),
+                                    sender!.ObservableForProperty(property8, false, false),
+                                    sender!.ObservableForProperty(property9, false, false),
+                                    sender!.ObservableForProperty(property10, false, false),
+                                    sender!.ObservableForProperty(property11, false, false),
+                                    sender!.ObservableForProperty(property12, false, false),
                                 selector
             );
                     }
@@ -1566,20 +1566,20 @@ public static class WhenAnyObservableMixin
         /// <summary>Observe a observable which is set to a property, and automatically subscribe to the most recent emitted value.</summary>
         /// <param name="sender">The object where the property chain starts.</param>
         /// <param name="obs1">The first observable to observe.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1)
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, x => x.Value.EmptyIfNull()).Switch();
+            return sender.WhenAny(obs1, x => x.Value!.EmptyIfNull()).Switch();
         }
 
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
         /// <param name="sender">The object where the property chain starts.</param>
         /// <param name="obs1">The 1 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs2">The 2 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, (o1, o2) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, (o1, o2) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1587,10 +1587,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs1">The 1 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs2">The 2 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs3">The 3 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, (o1, o2, o3) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, (o1, o2, o3) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1599,10 +1599,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs2">The 2 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs3">The 3 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs4">The 4 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, (o1, o2, o3, o4) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, (o1, o2, o3, o4) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1612,10 +1612,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs3">The 3 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs4">The 4 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs5">The 5 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, (o1, o2, o3, o4, o5) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, (o1, o2, o3, o4, o5) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1626,10 +1626,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs4">The 4 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs5">The 5 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs6">The 6 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, (o1, o2, o3, o4, o5, o6) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, (o1, o2, o3, o4, o5, o6) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1641,10 +1641,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs5">The 5 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs6">The 6 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs7">The 7 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, (o1, o2, o3, o4, o5, o6, o7) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, (o1, o2, o3, o4, o5, o6, o7) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1657,10 +1657,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs6">The 6 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs7">The 7 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs8">The 8 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, (o1, o2, o3, o4, o5, o6, o7, o8) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, (o1, o2, o3, o4, o5, o6, o7, o8) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1674,10 +1674,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs7">The 7 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs8">The 8 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs9">The 9 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, (o1, o2, o3, o4, o5, o6, o7, o8, o9) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, (o1, o2, o3, o4, o5, o6, o7, o8, o9) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1692,10 +1692,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs8">The 8 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs9">The 9 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs10">The 10 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9, Expression<Func<TSender, IObservable<TRet>?>> obs10)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9, Expression<Func<TSender, IObservable<TRet>?>> obs10)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull(), o10.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull(), o10.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1711,10 +1711,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs9">The 9 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs10">The 10 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs11">The 11 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9, Expression<Func<TSender, IObservable<TRet>?>> obs10, Expression<Func<TSender, IObservable<TRet>?>> obs11)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9, Expression<Func<TSender, IObservable<TRet>?>> obs10, Expression<Func<TSender, IObservable<TRet>?>> obs11)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull(), o10.Value.EmptyIfNull(), o11.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull(), o10.Value!.EmptyIfNull(), o11.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1731,10 +1731,10 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs10">The 10 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs11">The 11 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
         /// <param name="obs12">The 12 property chain to reference which ends with an observable. This will be a expression pointing to a end property or field which must be an observable.</param>
-                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9, Expression<Func<TSender, IObservable<TRet>?>> obs10, Expression<Func<TSender, IObservable<TRet>?>> obs11, Expression<Func<TSender, IObservable<TRet>?>> obs12)
+                public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1, Expression<Func<TSender, IObservable<TRet>?>> obs2, Expression<Func<TSender, IObservable<TRet>?>> obs3, Expression<Func<TSender, IObservable<TRet>?>> obs4, Expression<Func<TSender, IObservable<TRet>?>> obs5, Expression<Func<TSender, IObservable<TRet>?>> obs6, Expression<Func<TSender, IObservable<TRet>?>> obs7, Expression<Func<TSender, IObservable<TRet>?>> obs8, Expression<Func<TSender, IObservable<TRet>?>> obs9, Expression<Func<TSender, IObservable<TRet>?>> obs10, Expression<Func<TSender, IObservable<TRet>?>> obs11, Expression<Func<TSender, IObservable<TRet>?>> obs12)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, obs12, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11, o12) => new[] {o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull(), o10.Value.EmptyIfNull(), o11.Value.EmptyIfNull(), o12.Value.EmptyIfNull()})
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, obs12, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11, o12) => new[] {o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull(), o10.Value!.EmptyIfNull(), o11.Value!.EmptyIfNull(), o12.Value!.EmptyIfNull()})
                 .Select(x => x.Merge()).Switch();
         }
 
@@ -1743,13 +1743,13 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? s
         /// <param name="obs1">The 1 property chain to reference.</param>
         /// <param name="obs2">The 2 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Func<T1?, T2?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, (o1, o2) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, (o1, o2) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1758,14 +1758,14 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2>(this TSe
         /// <param name="obs2">The 2 property chain to reference.</param>
         /// <param name="obs3">The 3 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
                             Func<T1?, T2?, T3?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, (o1, o2, o3) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, (o1, o2, o3) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1775,7 +1775,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3>(this
         /// <param name="obs3">The 3 property chain to reference.</param>
         /// <param name="obs4">The 4 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1783,7 +1783,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4>(th
                             Func<T1?, T2?, T3?, T4?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, (o1, o2, o3, o4) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, (o1, o2, o3, o4) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1794,7 +1794,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4>(th
         /// <param name="obs4">The 4 property chain to reference.</param>
         /// <param name="obs5">The 5 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1803,7 +1803,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5>
                             Func<T1?, T2?, T3?, T4?, T5?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, (o1, o2, o3, o4, o5) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, (o1, o2, o3, o4, o5) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1815,7 +1815,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5>
         /// <param name="obs5">The 5 property chain to reference.</param>
         /// <param name="obs6">The 6 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1825,7 +1825,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
                             Func<T1?, T2?, T3?, T4?, T5?, T6?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, (o1, o2, o3, o4, o5, o6) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, (o1, o2, o3, o4, o5, o6) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1838,7 +1838,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
         /// <param name="obs6">The 6 property chain to reference.</param>
         /// <param name="obs7">The 7 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1849,7 +1849,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
                             Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, (o1, o2, o3, o4, o5, o6, o7) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, (o1, o2, o3, o4, o5, o6, o7) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1863,7 +1863,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
         /// <param name="obs7">The 7 property chain to reference.</param>
         /// <param name="obs8">The 8 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1875,7 +1875,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
                             Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, (o1, o2, o3, o4, o5, o6, o7, o8) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, (o1, o2, o3, o4, o5, o6, o7, o8) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1890,7 +1890,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
         /// <param name="obs8">The 8 property chain to reference.</param>
         /// <param name="obs9">The 9 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1903,7 +1903,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
                             Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, (o1, o2, o3, o4, o5, o6, o7, o8, o9) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, (o1, o2, o3, o4, o5, o6, o7, o8, o9) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1919,7 +1919,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
         /// <param name="obs9">The 9 property chain to reference.</param>
         /// <param name="obs10">The 10 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1933,7 +1933,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
                             Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull(), o10.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull(), o10.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1950,7 +1950,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
         /// <param name="obs10">The 10 property chain to reference.</param>
         /// <param name="obs11">The 11 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1965,7 +1965,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
                             Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull(), o10.Value.EmptyIfNull(), o11.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull(), o10.Value!.EmptyIfNull(), o11.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
         /// <summary>Monitor a property that is an observable, and subscribe to the most recent emitted value.</summary>
@@ -1983,7 +1983,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
         /// <param name="obs11">The 11 property chain to reference.</param>
         /// <param name="obs12">The 12 property chain to reference.</param>
         /// <param name="selector">The selector which will determine the final value from the properties. This must be an observable.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12>(this TSender sender,
                             Expression<Func<TSender, IObservable<T1>?>> obs1,
                             Expression<Func<TSender, IObservable<T2>?>> obs2,
                             Expression<Func<TSender, IObservable<T3>?>> obs3,
@@ -1999,7 +1999,7 @@ public static IObservable<TRet> WhenAnyObservable<TSender, TRet, T1,T2,T3,T4,T5,
                             Func<T1?, T2?, T3?, T4?, T5?, T6?, T7?, T8?, T9?, T10?, T11?, T12?, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, obs12, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11, o12) => Observable.CombineLatest(o1.Value.EmptyIfNull(), o2.Value.EmptyIfNull(), o3.Value.EmptyIfNull(), o4.Value.EmptyIfNull(), o5.Value.EmptyIfNull(), o6.Value.EmptyIfNull(), o7.Value.EmptyIfNull(), o8.Value.EmptyIfNull(), o9.Value.EmptyIfNull(), o10.Value.EmptyIfNull(), o11.Value.EmptyIfNull(), o12.Value.EmptyIfNull(), selector))
+            return sender.WhenAny(obs1, obs2, obs3, obs4, obs5, obs6, obs7, obs8, obs9, obs10, obs11, obs12, (o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11, o12) => Observable.CombineLatest(o1.Value!.EmptyIfNull(), o2.Value!.EmptyIfNull(), o3.Value!.EmptyIfNull(), o4.Value!.EmptyIfNull(), o5.Value!.EmptyIfNull(), o6.Value!.EmptyIfNull(), o7.Value!.EmptyIfNull(), o8.Value!.EmptyIfNull(), o9.Value!.EmptyIfNull(), o10.Value!.EmptyIfNull(), o11.Value!.EmptyIfNull(), o12.Value!.EmptyIfNull(), selector))
                 .Switch();
         }
 }
diff --git a/src/ReactiveUI/VariadicTemplates.tt b/src/ReactiveUI/VariadicTemplates.tt
index 670e9c7957..b07536de57 100644
--- a/src/ReactiveUI/VariadicTemplates.tt
+++ b/src/ReactiveUI/VariadicTemplates.tt
@@ -46,9 +46,9 @@ namespace ReactiveUI
         /// <param name="property1">The first property chain to reference. This will be a expression pointing to a end property or field.</param>
         public static IObservable<TRet> WhenAnyValue<TSender, TRet>(
             this TSender? sender,
-            Expression<Func<TSender, TRet?>> property1)
+            Expression<Func<TSender, TRet>> property1)
         {
-            return sender.WhenAny(property1, (IObservedChange<TSender, TRet> c1) => c1.Value);
+            return sender!.WhenAny(property1, (IObservedChange<TSender, TRet> c1) => c1.Value);
         }
 
         <# for(int length=1; length <= maxFuncLength; length++) { #>
@@ -74,11 +74,11 @@ namespace ReactiveUI
         <# } #>public static IObservable<(<#= String.Join(",", templParams) #>)> WhenAnyValue<TSender, <#= String.Join(",", templParamsDec) #>>(
             this TSender? sender,
             <# for(int i=1; i <= length; i++) { #>
-            Expression<Func<TSender, T<#=i#>?>> property<#=i#><# if (i != length) { #>,<# } #>
+            Expression<Func<TSender, T<#=i#>>> property<#=i#><# if (i != length) { #>,<# } #>
 
             <# } #>)
         {
-            return sender.WhenAny(<#= valuePropertyParams #>,
+            return sender!.WhenAny(<#= valuePropertyParams #>,
                                 (<#= valueSelectorParams #>) =>
                                     (<#= valueSelectorArgs #>));
         }
@@ -98,11 +98,11 @@ namespace ReactiveUI
         public static IObservable<TRet> WhenAnyValue<TSender, TRet, <#= String.Join(",", templParamsDec) #>>(
             this TSender? sender,
             <# for(int i=1; i <= length; i++) { #>
-            Expression<Func<TSender, T<#=i#>?>> property<#=i#>,
+            Expression<Func<TSender, T<#=i#>>> property<#=i#>,
             <# } #>
             Func<<#= String.Join(",", templParams) #>, TRet> selector)
         {
-            return sender.WhenAny(<#= valuePropertyParams #>,
+            return sender!.WhenAny(<#= valuePropertyParams #>,
                                 (<#= valueSelectorParams #>) =>
                                     selector(<#= valueSelectorArgs #>));
         }
@@ -121,16 +121,16 @@ namespace ReactiveUI
         public static IObservable<TRet> WhenAny<TSender, TRet, <#= String.Join(",", templParamsDec) #>>(
                 this TSender? sender,
             <# for(int i=1; i <= length; i++) { #>
-                Expression<Func<TSender, T<#=i#>?>> property<#=i#>,
+                Expression<Func<TSender, T<#=i#>>> property<#=i#>,
             <# } #>
                 Func<<#= selectorTypeParams #>, TRet> selector)
         {
             <# if (length == 1){ #>
-                return sender.ObservableForProperty(property<#=1#>, false, false).Select(selector);
+                return sender!.ObservableForProperty(property<#=1#>, false, false).Select(selector);
             <# }else{ #>
             return Observable.CombineLatest(
                 <# for(int i=1; i <= length; i++) { #>
-                    sender.ObservableForProperty(property<#=i#>, false, false),
+                    sender!.ObservableForProperty(property<#=i#>, false, false),
                 <# } #>
                 selector
             );
@@ -178,10 +178,10 @@ namespace ReactiveUI
         /// <summary>Observe a observable which is set to a property, and automatically subscribe to the most recent emitted value.</summary>
         /// <param name="sender">The object where the property chain starts.</param>
         /// <param name="obs1">The first observable to observe.</param>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, Expression<Func<TSender, IObservable<TRet>?>> obs1)
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, Expression<Func<TSender, IObservable<TRet>?>> obs1)
             where TSender : class
         {
-            return sender!.WhenAny(obs1, x => x.Value.EmptyIfNull()).Switch();
+            return sender.WhenAny(obs1, x => x.Value!.EmptyIfNull()).Switch();
         }
 
 <# for(int length=2; length <= maxFuncLength; length++) { #>
@@ -192,11 +192,11 @@ namespace ReactiveUI
         <# } #>
 <# string paramsStr = String.Join(", ", Enumerable.Range(1, length).Select(x => "Expression<Func<TSender, IObservable<TRet>?>> obs" + x.ToString())); #>
 <# string varsStr = String.Join(", ", Enumerable.Range(1, length).Select(x => "obs" + x.ToString())); #>
-<# string valsStr = String.Join(", ", Enumerable.Range(1, length).Select(x => "o" + x.ToString() + ".Value.EmptyIfNull()")); #>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender? sender, <#= paramsStr #>)
+<# string valsStr = String.Join(", ", Enumerable.Range(1, length).Select(x => "o" + x.ToString() + ".Value!.EmptyIfNull()")); #>
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet>(this TSender sender, <#= paramsStr #>)
             where TSender : class
         {
-            return sender!.WhenAny(<#= varsStr #>, (<#=varsStr.Replace("obs", "o")#>) => new[] {<#= valsStr #>})
+            return sender.WhenAny(<#= varsStr #>, (<#=varsStr.Replace("obs", "o")#>) => new[] {<#= valsStr #>})
                 .Select(x => x.Merge()).Switch();
         }
 <# } #>
@@ -210,16 +210,16 @@ namespace ReactiveUI
 <# var templParams = Enumerable.Range(1, length).Select(x => "T" + x.ToString() + "?"); #>
 <# var templParamsDec = Enumerable.Range(1, length).Select(x => "T" + x.ToString()); #>
 <# string varsStr = String.Join(", ", Enumerable.Range(1, length).Select(x => "obs" + x.ToString())); #>
-<# string valsStr = String.Join(", ", Enumerable.Range(1, length).Select(x => "o" + x.ToString() + ".Value.EmptyIfNull()")); #>
+<# string valsStr = String.Join(", ", Enumerable.Range(1, length).Select(x => "o" + x.ToString() + ".Value!.EmptyIfNull()")); #>
 <# string selectorTypeParams = String.Join(", ", templParams); #>
-        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, <#= String.Join(",", templParamsDec) #>>(this TSender? sender,
+        public static IObservable<TRet> WhenAnyObservable<TSender, TRet, <#= String.Join(",", templParamsDec) #>>(this TSender sender,
             <# for(int i=1; i <= length; i++) { #>
                 Expression<Func<TSender, IObservable<T<#=i#>>?>> obs<#=i#>,
             <# } #>
                 Func<<#= selectorTypeParams #>, TRet> selector)
             where TSender : class
         {
-            return sender!.WhenAny(<#= varsStr #>, (<#=varsStr.Replace("obs", "o")#>) => Observable.CombineLatest(<#= valsStr #>, selector))
+            return sender.WhenAny(<#= varsStr #>, (<#=varsStr.Replace("obs", "o")#>) => Observable.CombineLatest(<#= valsStr #>, selector))
                 .Switch();
         }
 <# } #>