feature WhenAnyObservable, WhenAny and WhenAnyValue to make Nullable

.editorconfig

@@ -42,9 +42,9 @@ dotnet_style_qualification_for_method = false:suggestion
 dotnet_style_qualification_for_event = false:suggestion
 
 # Types: use keywords instead of BCL types, and permit var only when the type is clear
-csharp_style_var_for_built_in_types = false:suggestion
-csharp_style_var_when_type_is_apparent = false:none
-csharp_style_var_elsewhere = false:suggestion
+csharp_style_var_for_built_in_types = true:suggestion
+csharp_style_var_when_type_is_apparent = true:none
+csharp_style_var_elsewhere = true:suggestion
 dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
 dotnet_style_predefined_type_for_member_access = true:suggestion
 

src/ReactiveUI.Fody.Analyzer.Test/Helpers/CodeFixVerifier.Helper.cs

@@ -48,8 +48,8 @@ private static IEnumerable<Diagnostic> GetNewDiagnostics(IEnumerable<Diagnostic>
             var oldArray = diagnostics.OrderBy(d => d.Location.SourceSpan.Start).ToArray();
             var newArray = newDiagnostics.OrderBy(d => d.Location.SourceSpan.Start).ToArray();
 
-            int oldIndex = 0;
-            int newIndex = 0;
+            var oldIndex = 0;
+            var newIndex = 0;
 
             while (newIndex < newArray.Length)
             {

src/ReactiveUI.Fody.Analyzer.Test/Helpers/DiagnosticResult.cs

@@ -91,7 +91,7 @@ public bool Equals(DiagnosticResult other) =>
         /// <inheritdoc/>
         public override int GetHashCode()
         {
-            int hashCode = 1054991603;
+            var hashCode = 1054991603;
             hashCode = (hashCode * -1521134295) + EqualityComparer<IList<DiagnosticResultLocation>>.Default.GetHashCode(_locations);
             hashCode = (hashCode * -1521134295) + EqualityComparer<IList<DiagnosticResultLocation>>.Default.GetHashCode(Locations);
             hashCode = (hashCode * -1521134295) + Severity.GetHashCode();

src/ReactiveUI.Fody.Analyzer.Test/Helpers/DiagnosticVerifier.Helper.cs

@@ -148,8 +148,8 @@ private static Document[] GetDocuments(string[] sources, string language)
         /// <returns>A Project created out of the Documents created from the source strings.</returns>
         private static Project? CreateProject(string[] sources, string language = LanguageNames.CSharp)
         {
-            string fileNamePrefix = DefaultFilePathPrefix;
-            string fileExt = language == LanguageNames.CSharp ? CSharpDefaultFileExt : VisualBasicDefaultExt;
+            var fileNamePrefix = DefaultFilePathPrefix;
+            var fileExt = language == LanguageNames.CSharp ? CSharpDefaultFileExt : VisualBasicDefaultExt;
 
             var projectId = ProjectId.CreateNewId(debugName: TestProjectName);
 
@@ -163,7 +163,7 @@ private static Document[] GetDocuments(string[] sources, string language)
                 .AddMetadataReference(projectId, ReactiveUi)
                 .AddMetadataReference(projectId, ReactiveUiHelper);
 
-            int count = 0;
+            var count = 0;
             foreach (var source in sources)
             {
                 var newFileName = fileNamePrefix + count + "." + fileExt;

src/ReactiveUI.Fody.Analyzer.Test/Verifiers/DiagnosticVerifier.cs

@@ -74,20 +74,20 @@ public abstract partial class DiagnosticVerifier
         /// <param name="expectedResults">Diagnostic Results that should have appeared in the code.</param>
         private static void VerifyDiagnosticResults(IEnumerable<Diagnostic> actualResults, DiagnosticAnalyzer analyzer, params DiagnosticResult[] expectedResults)
         {
-            int expectedCount = expectedResults.Length;
+            var expectedCount = expectedResults.Length;
             var actualCountList = actualResults.ToList();
-            int actualCount = actualCountList.Count;
+            var actualCount = actualCountList.Count;
 
             if (expectedCount != actualCount)
             {
-                string diagnosticsOutput = actualCountList.Any() ? FormatDiagnostics(analyzer, actualCountList.ToArray()) : "    NONE.";
+                var diagnosticsOutput = actualCountList.Any() ? FormatDiagnostics(analyzer, actualCountList.ToArray()) : "    NONE.";
 
                 Assert.True(
                     false,
                     $"Mismatch between number of diagnostics returned, expected \"{expectedCount}\" actual \"{actualCount}\"\r\n\r\nDiagnostics:\r\n{diagnosticsOutput}\r\n");
             }
 
-            for (int i = 0; i < expectedResults.Length; i++)
+            for (var i = 0; i < expectedResults.Length; i++)
             {
                 var actual = actualCountList[i];
                 var expected = expectedResults[i];
@@ -113,7 +113,7 @@ private static void VerifyDiagnosticResults(IEnumerable<Diagnostic> actualResult
                                       $"Expected {expected.Locations.Count - 1} additional locations but got {additionalLocations.Length} for Diagnostic:\r\n    {FormatDiagnostics(analyzer, actual)}\r\n");
                     }
 
-                    for (int j = 0; j < additionalLocations.Length; ++j)
+                    for (var j = 0; j < additionalLocations.Length; ++j)
                     {
                         VerifyDiagnosticLocation(analyzer, actual, additionalLocations[j], expected.Locations[j + 1]);
                     }
@@ -192,7 +192,7 @@ private static void VerifyDiagnosticLocation(DiagnosticAnalyzer analyzer, Diagno
         private static string FormatDiagnostics(DiagnosticAnalyzer analyzer, params Diagnostic[] diagnostics)
         {
             var builder = new StringBuilder();
-            for (int i = 0; i < diagnostics.Length; ++i)
+            for (var i = 0; i < diagnostics.Length; ++i)
             {
                 builder.AppendLine("// " + diagnostics[i].ToString());
 
@@ -214,7 +214,7 @@ private static string FormatDiagnostics(DiagnosticAnalyzer analyzer, params Diag
                                 location.IsInSource,
                                 $"Test base does not currently handle diagnostics in metadata locations. Diagnostic in metadata: {diagnostics[i]}\r\n");
 
-                            string resultMethodName = diagnostics[i].Location.SourceTree!.FilePath.EndsWith(".cs", StringComparison.Ordinal) ? "GetCSharpResultAt" : "GetBasicResultAt";
+                            var resultMethodName = diagnostics[i].Location.SourceTree!.FilePath.EndsWith(".cs", StringComparison.Ordinal) ? "GetCSharpResultAt" : "GetBasicResultAt";
                             var linePosition = diagnostics[i].Location.GetLineSpan().StartLinePosition;
 
                             builder.Append($"{resultMethodName}({linePosition.Line + 1}, {linePosition.Character + 1}, {analyzerType.Name}.{rule.Id})");

src/ReactiveUI.Fody.Analyzer/ReactiveObjectAnalyzer.cs

@@ -116,8 +116,8 @@ private static bool HasBackingField(PropertyDeclarationSyntax property)
                 return setter?.ExpressionBody is not null && getter?.ExpressionBody is not null;
             }
 
-            bool setterHasBodyStatements = setter.Body.Statements.Any();
-            bool getterHasBodyStatements = getter.Body.Statements.Any();
+            var setterHasBodyStatements = setter.Body.Statements.Any();
+            var getterHasBodyStatements = getter.Body.Statements.Any();
 
             return setterHasBodyStatements && getterHasBodyStatements;
         }

src/ReactiveUI.Fody.Tests/ApiApprovalBase.cs

@@ -45,7 +45,7 @@ protected static void CheckApproval(Assembly assembly, [CallerMemberName]string?
                 var approvedFileName = Path.Combine(sourceDirectory, $"ApiApprovalTests.{memberName}.{targetFrameworkName}.approved.txt");
                 var receivedFileName = Path.Combine(sourceDirectory, $"ApiApprovalTests.{memberName}.{targetFrameworkName}.received.txt");
 
-                string approvedPublicApi = string.Empty;
+                var approvedPublicApi = string.Empty;
 
                 if (File.Exists(approvedFileName))
                 {