diff --git a/src/EFCore.Proxies/Proxies/Internal/PropertyChangedInterceptor.cs b/src/EFCore.Proxies/Proxies/Internal/PropertyChangedInterceptor.cs
index f5d1e64adba..e78c7bf02b8 100644
--- a/src/EFCore.Proxies/Proxies/Internal/PropertyChangedInterceptor.cs
+++ b/src/EFCore.Proxies/Proxies/Internal/PropertyChangedInterceptor.cs
@@ -75,7 +75,7 @@ public virtual void Intercept(IInvocation invocation)
 
                 if (navigation != null)
                 {
-                    HandleChanged(invocation, navigation, LegacyReferenceEqualityComparer.Instance);
+                    HandleChanged(invocation, navigation, ReferenceEqualityComparer.Instance);
                 }
                 else
                 {
diff --git a/src/EFCore.Proxies/Proxies/Internal/PropertyChangingInterceptor.cs b/src/EFCore.Proxies/Proxies/Internal/PropertyChangingInterceptor.cs
index 6bd1c5125eb..8b467c0e563 100644
--- a/src/EFCore.Proxies/Proxies/Internal/PropertyChangingInterceptor.cs
+++ b/src/EFCore.Proxies/Proxies/Internal/PropertyChangingInterceptor.cs
@@ -75,7 +75,7 @@ public virtual void Intercept(IInvocation invocation)
 
                 if (navigation != null)
                 {
-                    HandleChanging(invocation, navigation, LegacyReferenceEqualityComparer.Instance);
+                    HandleChanging(invocation, navigation, ReferenceEqualityComparer.Instance);
                 }
                 else
                 {
diff --git a/src/EFCore.Relational/Query/Internal/FromSqlParameterExpandingExpressionVisitor.cs b/src/EFCore.Relational/Query/Internal/FromSqlParameterExpandingExpressionVisitor.cs
index 78a51e11b72..6cf339b80a1 100644
--- a/src/EFCore.Relational/Query/Internal/FromSqlParameterExpandingExpressionVisitor.cs
+++ b/src/EFCore.Relational/Query/Internal/FromSqlParameterExpandingExpressionVisitor.cs
@@ -17,7 +17,7 @@ namespace Microsoft.EntityFrameworkCore.Query.Internal;
 public class FromSqlParameterExpandingExpressionVisitor : ExpressionVisitor
 {
     private readonly IDictionary<FromSqlExpression, Expression> _visitedFromSqlExpressions
-        = new Dictionary<FromSqlExpression, Expression>(LegacyReferenceEqualityComparer.Instance);
+        = new Dictionary<FromSqlExpression, Expression>(ReferenceEqualityComparer.Instance);
 
     private readonly ISqlExpressionFactory _sqlExpressionFactory;
     private readonly IRelationalTypeMappingSource _typeMappingSource;
diff --git a/src/EFCore/ChangeTracking/Internal/ChangeDetector.cs b/src/EFCore/ChangeTracking/Internal/ChangeDetector.cs
index 34add1c5dac..349db5a3e7d 100644
--- a/src/EFCore/ChangeTracking/Internal/ChangeDetector.cs
+++ b/src/EFCore/ChangeTracking/Internal/ChangeDetector.cs
@@ -334,7 +334,7 @@ public bool DetectNavigationChange(InternalEntityEntry entry, INavigationBase na
             var snapshotCollection = (IEnumerable?)snapshotValue;
             var currentCollection = (IEnumerable?)currentValue;
 
-            var removed = new HashSet<object>(LegacyReferenceEqualityComparer.Instance);
+            var removed = new HashSet<object>(ReferenceEqualityComparer.Instance);
             if (snapshotCollection != null)
             {
                 foreach (var entity in snapshotCollection)
@@ -343,7 +343,7 @@ public bool DetectNavigationChange(InternalEntityEntry entry, INavigationBase na
                 }
             }
 
-            var added = new HashSet<object>(LegacyReferenceEqualityComparer.Instance);
+            var added = new HashSet<object>(ReferenceEqualityComparer.Instance);
             if (currentCollection != null)
             {
                 foreach (var entity in currentCollection)
diff --git a/src/EFCore/ChangeTracking/Internal/EntityReferenceMap.cs b/src/EFCore/ChangeTracking/Internal/EntityReferenceMap.cs
index 2cc5a760bbc..804b1cd9ec0 100644
--- a/src/EFCore/ChangeTracking/Internal/EntityReferenceMap.cs
+++ b/src/EFCore/ChangeTracking/Internal/EntityReferenceMap.cs
@@ -73,24 +73,24 @@ public EntityReferenceMap(bool hasSubMap)
                 switch (state)
                 {
                     case EntityState.Detached:
-                        _detachedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(LegacyReferenceEqualityComparer.Instance);
+                        _detachedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(ReferenceEqualityComparer.Instance);
                         _detachedReferenceMap[mapKey] = entry;
                         break;
                     case EntityState.Unchanged:
                         _unchangedReferenceMap ??=
-                            new Dictionary<object, InternalEntityEntry>(LegacyReferenceEqualityComparer.Instance);
+                            new Dictionary<object, InternalEntityEntry>(ReferenceEqualityComparer.Instance);
                         _unchangedReferenceMap[mapKey] = entry;
                         break;
                     case EntityState.Deleted:
-                        _deletedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(LegacyReferenceEqualityComparer.Instance);
+                        _deletedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(ReferenceEqualityComparer.Instance);
                         _deletedReferenceMap[mapKey] = entry;
                         break;
                     case EntityState.Modified:
-                        _modifiedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(LegacyReferenceEqualityComparer.Instance);
+                        _modifiedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(ReferenceEqualityComparer.Instance);
                         _modifiedReferenceMap[mapKey] = entry;
                         break;
                     case EntityState.Added:
-                        _addedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(LegacyReferenceEqualityComparer.Instance);
+                        _addedReferenceMap ??= new Dictionary<object, InternalEntityEntry>(ReferenceEqualityComparer.Instance);
                         _addedReferenceMap[mapKey] = entry;
                         break;
                 }
diff --git a/src/EFCore/ChangeTracking/Internal/IdentityMap.cs b/src/EFCore/ChangeTracking/Internal/IdentityMap.cs
index b150a0ac0b6..1e4af44a629 100644
--- a/src/EFCore/ChangeTracking/Internal/IdentityMap.cs
+++ b/src/EFCore/ChangeTracking/Internal/IdentityMap.cs
@@ -355,7 +355,7 @@ private void Add(TKey key, InternalEntityEntry entry, bool updateDuplicate)
     /// </summary>
     public virtual IDependentsMap GetDependentsMap(IForeignKey foreignKey)
     {
-        _dependentMaps ??= new Dictionary<IForeignKey, IDependentsMap>(LegacyReferenceEqualityComparer.Instance);
+        _dependentMaps ??= new Dictionary<IForeignKey, IDependentsMap>(ReferenceEqualityComparer.Instance);
 
         if (!_dependentMaps.TryGetValue(foreignKey, out var map))
         {
diff --git a/src/EFCore/ChangeTracking/Internal/RelationshipsSnapshot.cs b/src/EFCore/ChangeTracking/Internal/RelationshipsSnapshot.cs
index e95c0e4683d..0808c76618d 100644
--- a/src/EFCore/ChangeTracking/Internal/RelationshipsSnapshot.cs
+++ b/src/EFCore/ChangeTracking/Internal/RelationshipsSnapshot.cs
@@ -98,7 +98,7 @@ private HashSet<object> GetOrCreateCollection(int index)
             var snapshot = (HashSet<object>?)_values[index];
             if (snapshot == null)
             {
-                snapshot = new HashSet<object>(LegacyReferenceEqualityComparer.Instance);
+                snapshot = new HashSet<object>(ReferenceEqualityComparer.Instance);
                 _values[index] = snapshot;
             }
 
diff --git a/src/EFCore/ChangeTracking/Internal/SnapshotFactoryFactory.cs b/src/EFCore/ChangeTracking/Internal/SnapshotFactoryFactory.cs
index 112729c8681..6eaf3fd8052 100644
--- a/src/EFCore/ChangeTracking/Internal/SnapshotFactoryFactory.cs
+++ b/src/EFCore/ChangeTracking/Internal/SnapshotFactoryFactory.cs
@@ -268,5 +268,5 @@ protected virtual bool UseEntityVariable
     private static HashSet<object>? SnapshotCollection(IEnumerable<object>? collection)
         => collection == null
             ? null
-            : new HashSet<object>(collection, LegacyReferenceEqualityComparer.Instance);
+            : new HashSet<object>(collection, ReferenceEqualityComparer.Instance);
 }
diff --git a/src/EFCore/ChangeTracking/Internal/StateManager.cs b/src/EFCore/ChangeTracking/Internal/StateManager.cs
index b4f08bf7850..6966c5b2361 100644
--- a/src/EFCore/ChangeTracking/Internal/StateManager.cs
+++ b/src/EFCore/ChangeTracking/Internal/StateManager.cs
@@ -740,7 +740,7 @@ public virtual void AbortAttachGraph()
         InternalEntityEntry referencedFromEntry)
     {
         _referencedUntrackedEntities ??=
-            new Dictionary<object, IList<Tuple<INavigationBase, InternalEntityEntry>>>(LegacyReferenceEqualityComparer.Instance);
+            new Dictionary<object, IList<Tuple<INavigationBase, InternalEntityEntry>>>(ReferenceEqualityComparer.Instance);
 
         if (!_referencedUntrackedEntities.TryGetValue(referencedEntity, out var danglers))
         {
diff --git a/src/EFCore/Metadata/Internal/ClrCollectionAccessorFactory.cs b/src/EFCore/Metadata/Internal/ClrCollectionAccessorFactory.cs
index 4da6686a02f..235726c192a 100644
--- a/src/EFCore/Metadata/Internal/ClrCollectionAccessorFactory.cs
+++ b/src/EFCore/Metadata/Internal/ClrCollectionAccessorFactory.cs
@@ -257,7 +257,7 @@ private static bool IsObservableHashSet(Type type)
         where TCollection : class
         where TElement : class
     {
-        var collection = (TCollection)(ICollection<TElement>)new HashSet<TElement>(LegacyReferenceEqualityComparer.Instance);
+        var collection = (TCollection)(ICollection<TElement>)new HashSet<TElement>(ReferenceEqualityComparer.Instance);
         setterDelegate(entity, collection);
         return collection;
     }
@@ -266,7 +266,7 @@ private static bool IsObservableHashSet(Type type)
     private static TCollection CreateHashSet<TCollection, TElement>()
         where TCollection : class
         where TElement : class
-        => (TCollection)(ICollection<TElement>)new HashSet<TElement>(LegacyReferenceEqualityComparer.Instance);
+        => (TCollection)(ICollection<TElement>)new HashSet<TElement>(ReferenceEqualityComparer.Instance);
 
     [UsedImplicitly]
     private static TCollection CreateAndSetObservableHashSet<TEntity, TCollection, TElement>(
@@ -276,7 +276,7 @@ private static bool IsObservableHashSet(Type type)
         where TCollection : class
         where TElement : class
     {
-        var collection = (TCollection)(ICollection<TElement>)new ObservableHashSet<TElement>(LegacyReferenceEqualityComparer.Instance);
+        var collection = (TCollection)(ICollection<TElement>)new ObservableHashSet<TElement>(ReferenceEqualityComparer.Instance);
         setterDelegate(entity, collection);
         return collection;
     }
@@ -285,5 +285,5 @@ private static bool IsObservableHashSet(Type type)
     private static TCollection CreateObservableHashSet<TCollection, TElement>()
         where TCollection : class
         where TElement : class
-        => (TCollection)(ICollection<TElement>)new ObservableHashSet<TElement>(LegacyReferenceEqualityComparer.Instance);
+        => (TCollection)(ICollection<TElement>)new ObservableHashSet<TElement>(ReferenceEqualityComparer.Instance);
 }
diff --git a/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs b/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs
index 45115fbb5b8..2267274cf5a 100644
--- a/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs
+++ b/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs
@@ -3610,7 +3610,7 @@ private static InternalForeignKeyBuilder MergeFacetsFrom(Navigation newNavigatio
             }
         }
 
-        if (dependentEntityType.GetForeignKeys().Contains(Metadata, LegacyReferenceEqualityComparer.Instance))
+        if (dependentEntityType.GetForeignKeys().Contains(Metadata, ReferenceEqualityComparer.Instance))
         {
             Check.DebugAssert(Metadata.IsInModel, "Metadata isn't in the model");
 
diff --git a/src/Shared/ReferenceEqualityComparer.cs b/src/Shared/ReferenceEqualityComparer.cs
deleted file mode 100644
index 5e685ad4f09..00000000000
--- a/src/Shared/ReferenceEqualityComparer.cs
+++ /dev/null
@@ -1,39 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-#nullable enable
-
-using System.Collections;
-using System.Collections.Generic;
-using System.Runtime.CompilerServices;
-
-#pragma warning disable RS1024 // Compare symbols correctly (for Roslyn analyzers only)
-
-namespace Microsoft.EntityFrameworkCore.Internal;
-
-internal sealed class LegacyReferenceEqualityComparer : IEqualityComparer<object>, IEqualityComparer
-{
-    private LegacyReferenceEqualityComparer()
-    {
-    }
-
-    public static LegacyReferenceEqualityComparer Instance { get; } = new();
-
-    public new bool Equals(object? x, object? y)
-        => ReferenceEquals(x, y);
-
-    public int GetHashCode(object obj)
-        => RuntimeHelpers.GetHashCode(obj);
-
-    bool IEqualityComparer<object>.Equals(object? x, object? y)
-        => ReferenceEquals(x, y);
-
-    int IEqualityComparer.GetHashCode(object obj)
-        => RuntimeHelpers.GetHashCode(obj);
-
-    bool IEqualityComparer.Equals(object? x, object? y)
-        => ReferenceEquals(x, y);
-
-    int IEqualityComparer<object>.GetHashCode(object obj)
-        => RuntimeHelpers.GetHashCode(obj);
-}
diff --git a/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeNoTrackingQueryTestBase.cs b/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeNoTrackingQueryTestBase.cs
index d4982bc66b1..4aa984a11e5 100644
--- a/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeNoTrackingQueryTestBase.cs
+++ b/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeNoTrackingQueryTestBase.cs
@@ -57,7 +57,7 @@ var customer
                     .AsNoTracking()
                     .Single(c => c.CustomerID == "ALFKI");
 
-        Assert.NotEqual(orders, customer.Orders, LegacyReferenceEqualityComparer.Instance);
+        Assert.NotEqual(orders, customer.Orders, ReferenceEqualityComparer.Instance);
         Assert.Equal(6, customer.Orders.Count);
         Assert.True(customer.Orders.All(e => ReferenceEquals(e.Customer, customer)));
 
diff --git a/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeQueryTestBase.cs b/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeQueryTestBase.cs
index 08f3a63f620..747b26628e3 100644
--- a/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeQueryTestBase.cs
+++ b/test/EFCore.Relational.Specification.Tests/Query/NorthwindSplitIncludeQueryTestBase.cs
@@ -54,7 +54,7 @@ var customer
                     .AsSplitQuery()
                     .Single(c => c.CustomerID == "ALFKI");
 
-        Assert.Equal(orders, customer.Orders, LegacyReferenceEqualityComparer.Instance);
+        Assert.Equal(orders, customer.Orders, ReferenceEqualityComparer.Instance);
         Assert.Equal(6, customer.Orders.Count);
         Assert.True(orders.All(o => ReferenceEquals(o.Customer, customer)));
         Assert.Equal(6 + 1, context.ChangeTracker.Entries().Count());
diff --git a/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBase.cs b/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBase.cs
index 8519cfe7955..27ab87f1a66 100644
--- a/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBase.cs
+++ b/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBase.cs
@@ -544,28 +544,28 @@ protected virtual object CreateFullGraph()
             {
                 AlternateId = RootAK,
                 RequiredChildren =
-                    new ObservableHashSet<Required1>(LegacyReferenceEqualityComparer.Instance)
+                    new ObservableHashSet<Required1>(ReferenceEqualityComparer.Instance)
                     {
                         new()
                         {
-                            Children = new ObservableHashSet<Required2>(LegacyReferenceEqualityComparer.Instance) { new(), new() }
+                            Children = new ObservableHashSet<Required2>(ReferenceEqualityComparer.Instance) { new(), new() }
                         },
-                        new() { Children = new ObservableHashSet<Required2>(LegacyReferenceEqualityComparer.Instance) { new(), new() } }
+                        new() { Children = new ObservableHashSet<Required2>(ReferenceEqualityComparer.Instance) { new(), new() } }
                     },
                 OptionalChildren =
-                    new ObservableHashSet<Optional1>(LegacyReferenceEqualityComparer.Instance)
+                    new ObservableHashSet<Optional1>(ReferenceEqualityComparer.Instance)
                     {
                         new()
                         {
-                            Children = new ObservableHashSet<Optional2>(LegacyReferenceEqualityComparer.Instance) { new(), new() },
+                            Children = new ObservableHashSet<Optional2>(ReferenceEqualityComparer.Instance) { new(), new() },
                             CompositeChildren =
-                                new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance)
+                                new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance)
                         },
                         new()
                         {
-                            Children = new ObservableHashSet<Optional2>(LegacyReferenceEqualityComparer.Instance) { new(), new() },
+                            Children = new ObservableHashSet<Optional2>(ReferenceEqualityComparer.Instance) { new(), new() },
                             CompositeChildren =
-                                new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance)
+                                new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance)
                         }
                     },
                 RequiredSingle = new RequiredSingle1 { Single = new RequiredSingle2() },
@@ -583,51 +583,51 @@ protected virtual object CreateFullGraph()
                         DerivedRoot = new Root()
                     },
                 RequiredChildrenAk =
-                    new ObservableHashSet<RequiredAk1>(LegacyReferenceEqualityComparer.Instance)
+                    new ObservableHashSet<RequiredAk1>(ReferenceEqualityComparer.Instance)
                     {
                         new()
                         {
                             AlternateId = Guid.NewGuid(),
-                            Children = new ObservableHashSet<RequiredAk2>(LegacyReferenceEqualityComparer.Instance)
+                            Children = new ObservableHashSet<RequiredAk2>(ReferenceEqualityComparer.Instance)
                             {
                                 new() { AlternateId = Guid.NewGuid() }, new() { AlternateId = Guid.NewGuid() }
                             },
                             CompositeChildren =
-                                new ObservableHashSet<RequiredComposite2>(LegacyReferenceEqualityComparer.Instance) { new(), new() }
+                                new ObservableHashSet<RequiredComposite2>(ReferenceEqualityComparer.Instance) { new(), new() }
                         },
                         new()
                         {
                             AlternateId = Guid.NewGuid(),
-                            Children = new ObservableHashSet<RequiredAk2>(LegacyReferenceEqualityComparer.Instance)
+                            Children = new ObservableHashSet<RequiredAk2>(ReferenceEqualityComparer.Instance)
                             {
                                 new() { AlternateId = Guid.NewGuid() }, new() { AlternateId = Guid.NewGuid() }
                             },
                             CompositeChildren =
-                                new ObservableHashSet<RequiredComposite2>(LegacyReferenceEqualityComparer.Instance) { new(), new() }
+                                new ObservableHashSet<RequiredComposite2>(ReferenceEqualityComparer.Instance) { new(), new() }
                         }
                     },
                 OptionalChildrenAk =
-                    new ObservableHashSet<OptionalAk1>(LegacyReferenceEqualityComparer.Instance)
+                    new ObservableHashSet<OptionalAk1>(ReferenceEqualityComparer.Instance)
                     {
                         new()
                         {
                             AlternateId = Guid.NewGuid(),
-                            Children = new ObservableHashSet<OptionalAk2>(LegacyReferenceEqualityComparer.Instance)
+                            Children = new ObservableHashSet<OptionalAk2>(ReferenceEqualityComparer.Instance)
                             {
                                 new() { AlternateId = Guid.NewGuid() }, new() { AlternateId = Guid.NewGuid() }
                             },
                             CompositeChildren =
-                                new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance) { new(), new() }
+                                new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance) { new(), new() }
                         },
                         new()
                         {
                             AlternateId = Guid.NewGuid(),
-                            Children = new ObservableHashSet<OptionalAk2>(LegacyReferenceEqualityComparer.Instance)
+                            Children = new ObservableHashSet<OptionalAk2>(ReferenceEqualityComparer.Instance)
                             {
                                 new() { AlternateId = Guid.NewGuid() }, new() { AlternateId = Guid.NewGuid() }
                             },
                             CompositeChildren =
-                                new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance) { new(), new() }
+                                new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance) { new(), new() }
                         }
                     },
                 RequiredSingleAk =
@@ -674,13 +674,13 @@ protected virtual object CreateFullGraph()
                         Root = new Root(),
                         DerivedRoot = new Root()
                     },
-                RequiredCompositeChildren = new ObservableHashSet<RequiredComposite1>(LegacyReferenceEqualityComparer.Instance)
+                RequiredCompositeChildren = new ObservableHashSet<RequiredComposite1>(ReferenceEqualityComparer.Instance)
                 {
                     new()
                     {
                         Id = 1,
                         CompositeChildren =
-                            new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance)
+                            new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance)
                             {
                                 new() { Id = 1 }, new() { Id = 2 }
                             }
@@ -689,7 +689,7 @@ protected virtual object CreateFullGraph()
                     {
                         Id = 2,
                         CompositeChildren =
-                            new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance)
+                            new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance)
                             {
                                 new() { Id = 3 }, new() { Id = 4 }
                             }
@@ -1146,8 +1146,8 @@ protected class Root : NotifyingEntity
     {
         private int _id;
         private Guid _alternateId;
-        private IEnumerable<Required1> _requiredChildren = new ObservableHashSet<Required1>(LegacyReferenceEqualityComparer.Instance);
-        private IEnumerable<Optional1> _optionalChildren = new ObservableHashSet<Optional1>(LegacyReferenceEqualityComparer.Instance);
+        private IEnumerable<Required1> _requiredChildren = new ObservableHashSet<Required1>(ReferenceEqualityComparer.Instance);
+        private IEnumerable<Optional1> _optionalChildren = new ObservableHashSet<Optional1>(ReferenceEqualityComparer.Instance);
         private RequiredSingle1 _requiredSingle;
         private RequiredNonPkSingle1 _requiredNonPkSingle;
         private RequiredNonPkSingle1Derived _requiredNonPkSingleDerived;
@@ -1157,10 +1157,10 @@ protected class Root : NotifyingEntity
         private OptionalSingle1MoreDerived _optionalSingleMoreDerived;
 
         private IEnumerable<RequiredAk1> _requiredChildrenAk =
-            new ObservableHashSet<RequiredAk1>(LegacyReferenceEqualityComparer.Instance);
+            new ObservableHashSet<RequiredAk1>(ReferenceEqualityComparer.Instance);
 
         private IEnumerable<OptionalAk1> _optionalChildrenAk =
-            new ObservableHashSet<OptionalAk1>(LegacyReferenceEqualityComparer.Instance);
+            new ObservableHashSet<OptionalAk1>(ReferenceEqualityComparer.Instance);
 
         private RequiredSingleAk1 _requiredSingleAk;
         private RequiredNonPkSingleAk1 _requiredNonPkSingleAk;
@@ -1171,7 +1171,7 @@ protected class Root : NotifyingEntity
         private OptionalSingleAk1MoreDerived _optionalSingleAkMoreDerived;
 
         private IEnumerable<RequiredComposite1> _requiredCompositeChildren
-            = new ObservableHashSet<RequiredComposite1>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<RequiredComposite1>(ReferenceEqualityComparer.Instance);
 
         public int Id
         {
@@ -1314,7 +1314,7 @@ protected class Required1 : NotifyingEntity
         private int _id;
         private int _parentId;
         private Root _parent;
-        private IEnumerable<Required2> _children = new ObservableHashSet<Required2>(LegacyReferenceEqualityComparer.Instance);
+        private IEnumerable<Required2> _children = new ObservableHashSet<Required2>(ReferenceEqualityComparer.Instance);
 
         public int Id
         {
@@ -1425,10 +1425,10 @@ protected class Optional1 : NotifyingEntity
         private int _id;
         private int? _parentId;
         private Root _parent;
-        private IEnumerable<Optional2> _children = new ObservableHashSet<Optional2>(LegacyReferenceEqualityComparer.Instance);
+        private IEnumerable<Optional2> _children = new ObservableHashSet<Optional2>(ReferenceEqualityComparer.Instance);
 
         private ICollection<OptionalComposite2> _compositeChildren =
-            new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance);
+            new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance);
 
         public int Id
         {
@@ -1926,10 +1926,10 @@ protected class RequiredAk1 : NotifyingEntity
         private Guid _alternateId;
         private Guid _parentId;
         private Root _parent;
-        private IEnumerable<RequiredAk2> _children = new ObservableHashSet<RequiredAk2>(LegacyReferenceEqualityComparer.Instance);
+        private IEnumerable<RequiredAk2> _children = new ObservableHashSet<RequiredAk2>(ReferenceEqualityComparer.Instance);
 
         private IEnumerable<RequiredComposite2> _compositeChildren =
-            new ObservableHashSet<RequiredComposite2>(LegacyReferenceEqualityComparer.Instance);
+            new ObservableHashSet<RequiredComposite2>(ReferenceEqualityComparer.Instance);
 
         public int Id
         {
@@ -2043,7 +2043,7 @@ protected class RequiredComposite1 : NotifyingEntity
         private Root _parent;
 
         private ICollection<OptionalOverlapping2> _compositeChildren =
-            new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance);
+            new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance);
 
         public int Id
         {
@@ -2192,10 +2192,10 @@ protected class OptionalAk1 : NotifyingEntity
         private Guid _alternateId;
         private Guid? _parentId;
         private Root _parent;
-        private IEnumerable<OptionalAk2> _children = new ObservableHashSet<OptionalAk2>(LegacyReferenceEqualityComparer.Instance);
+        private IEnumerable<OptionalAk2> _children = new ObservableHashSet<OptionalAk2>(ReferenceEqualityComparer.Instance);
 
         private ICollection<OptionalComposite2> _compositeChildren =
-            new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance);
+            new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance);
 
         public int Id
         {
@@ -2874,7 +2874,7 @@ protected class BadCustomer : NotifyingEntity
     {
         private int _id;
         private int _status;
-        private ICollection<BadOrder> _badOrders = new ObservableHashSet<BadOrder>(LegacyReferenceEqualityComparer.Instance);
+        private ICollection<BadOrder> _badOrders = new ObservableHashSet<BadOrder>(ReferenceEqualityComparer.Instance);
 
         public int Id
         {
@@ -3007,7 +3007,7 @@ public ParentAsAChild ParentAsAChild
 
     protected abstract class TaskWithChoices : QuestTask
     {
-        private ICollection<TaskChoice> _choices = new ObservableHashSet<TaskChoice>(LegacyReferenceEqualityComparer.Instance);
+        private ICollection<TaskChoice> _choices = new ObservableHashSet<TaskChoice>(ReferenceEqualityComparer.Instance);
 
         public ICollection<TaskChoice> Choices
         {
@@ -3044,7 +3044,7 @@ public int BarCode
     protected class Bloog : NotifyingEntity
     {
         private int _id;
-        private IEnumerable<Poost> _poosts = new ObservableHashSet<Poost>(LegacyReferenceEqualityComparer.Instance);
+        private IEnumerable<Poost> _poosts = new ObservableHashSet<Poost>(ReferenceEqualityComparer.Instance);
 
         [DatabaseGenerated(DatabaseGeneratedOption.None)]
         public int Id
@@ -3091,10 +3091,10 @@ protected class SharedFkRoot : NotifyingEntity
         private long _id;
 
         private ICollection<SharedFkDependant> _dependants
-            = new ObservableHashSet<SharedFkDependant>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<SharedFkDependant>(ReferenceEqualityComparer.Instance);
 
         private ICollection<SharedFkParent> _parents
-            = new ObservableHashSet<SharedFkParent>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<SharedFkParent>(ReferenceEqualityComparer.Instance);
 
         public long Id
         {
diff --git a/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBaseOneToMany.cs b/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBaseOneToMany.cs
index 70d3e290768..4c3b220bcba 100644
--- a/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBaseOneToMany.cs
+++ b/test/EFCore.Specification.Tests/GraphUpdates/GraphUpdatesTestBaseOneToMany.cs
@@ -695,7 +695,7 @@ public abstract partial class GraphUpdatesTestBase<TFixture>
                 {
                     newParent = new Optional1
                     {
-                        CompositeChildren = new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance)
+                        CompositeChildren = new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance)
                     };
 
                     context.Set<Optional1>().Add(newParent);
@@ -1120,7 +1120,7 @@ public abstract partial class GraphUpdatesTestBase<TFixture>
                     {
                         Id = 3,
                         Parent = context.Set<Root>().Single(IsTheRoot),
-                        CompositeChildren = new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance)
+                        CompositeChildren = new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance)
                         {
                             new() { Id = 5 }, new() { Id = 6 }
                         }
diff --git a/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesFixtureBase.cs b/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesFixtureBase.cs
index de8dbfbcace..e86cfc853c8 100644
--- a/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesFixtureBase.cs
+++ b/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesFixtureBase.cs
@@ -396,12 +396,12 @@ protected virtual object CreateFullGraph(DbContext context)
                 {
                     e.AlternateId = RootAK;
 
-                    e.RequiredChildren = new ObservableHashSet<Required1>(LegacyReferenceEqualityComparer.Instance)
+                    e.RequiredChildren = new ObservableHashSet<Required1>(ReferenceEqualityComparer.Instance)
                     {
                         context.CreateProxy<Required1>(
                             e =>
                             {
-                                e.Children = new ObservableHashSet<Required2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<Required2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<Required2>().CreateProxy(), context.Set<Required2>().CreateProxy()
                                 };
@@ -409,36 +409,36 @@ protected virtual object CreateFullGraph(DbContext context)
                         context.CreateProxy<Required1>(
                             e =>
                             {
-                                e.Children = new ObservableHashSet<Required2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<Required2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<Required2>().CreateProxy(), context.Set<Required2>().CreateProxy()
                                 };
                             })
                     };
 
-                    e.OptionalChildren = new ObservableHashSet<Optional1>(LegacyReferenceEqualityComparer.Instance)
+                    e.OptionalChildren = new ObservableHashSet<Optional1>(ReferenceEqualityComparer.Instance)
                     {
                         context.Set<Optional1>().CreateProxy(
                             e =>
                             {
-                                e.Children = new ObservableHashSet<Optional2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<Optional2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<Optional2>().CreateProxy(), context.Set<Optional2>().CreateProxy()
                                 };
 
                                 e.CompositeChildren =
-                                    new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance);
+                                    new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance);
                             }),
                         context.Set<Optional1>().CreateProxy(
                             e =>
                             {
-                                e.Children = new ObservableHashSet<Optional2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<Optional2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<Optional2>().CreateProxy(), context.Set<Optional2>().CreateProxy()
                                 };
 
                                 e.CompositeChildren =
-                                    new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance);
+                                    new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance);
                             })
                     };
 
@@ -472,21 +472,21 @@ protected virtual object CreateFullGraph(DbContext context)
                             e.DerivedRoot = context.Set<Root>().CreateProxy();
                         });
 
-                    e.RequiredChildrenAk = new ObservableHashSet<RequiredAk1>(LegacyReferenceEqualityComparer.Instance)
+                    e.RequiredChildrenAk = new ObservableHashSet<RequiredAk1>(ReferenceEqualityComparer.Instance)
                     {
                         context.Set<RequiredAk1>().CreateProxy(
                             e =>
                             {
                                 e.AlternateId = Guid.NewGuid();
 
-                                e.Children = new ObservableHashSet<RequiredAk2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<RequiredAk2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<RequiredAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid()),
                                     context.Set<RequiredAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid())
                                 };
 
                                 e.CompositeChildren =
-                                    new ObservableHashSet<RequiredComposite2>(LegacyReferenceEqualityComparer.Instance)
+                                    new ObservableHashSet<RequiredComposite2>(ReferenceEqualityComparer.Instance)
                                     {
                                         context.Set<RequiredComposite2>().CreateProxy(), context.Set<RequiredComposite2>().CreateProxy()
                                     };
@@ -496,34 +496,34 @@ protected virtual object CreateFullGraph(DbContext context)
                             {
                                 e.AlternateId = Guid.NewGuid();
 
-                                e.Children = new ObservableHashSet<RequiredAk2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<RequiredAk2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<RequiredAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid()),
                                     context.Set<RequiredAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid())
                                 };
 
                                 e.CompositeChildren =
-                                    new ObservableHashSet<RequiredComposite2>(LegacyReferenceEqualityComparer.Instance)
+                                    new ObservableHashSet<RequiredComposite2>(ReferenceEqualityComparer.Instance)
                                     {
                                         context.Set<RequiredComposite2>().CreateProxy(), context.Set<RequiredComposite2>().CreateProxy()
                                     };
                             })
                     };
 
-                    e.OptionalChildrenAk = new ObservableHashSet<OptionalAk1>(LegacyReferenceEqualityComparer.Instance)
+                    e.OptionalChildrenAk = new ObservableHashSet<OptionalAk1>(ReferenceEqualityComparer.Instance)
                     {
                         context.Set<OptionalAk1>().CreateProxy(
                             e =>
                             {
                                 e.AlternateId = Guid.NewGuid();
 
-                                e.Children = new ObservableHashSet<OptionalAk2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<OptionalAk2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<OptionalAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid()),
                                     context.Set<OptionalAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid())
                                 };
                                 e.CompositeChildren =
-                                    new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance)
+                                    new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance)
                                     {
                                         context.Set<OptionalComposite2>().CreateProxy(), context.Set<OptionalComposite2>().CreateProxy()
                                     };
@@ -533,14 +533,14 @@ protected virtual object CreateFullGraph(DbContext context)
                             {
                                 e.AlternateId = Guid.NewGuid();
 
-                                e.Children = new ObservableHashSet<OptionalAk2>(LegacyReferenceEqualityComparer.Instance)
+                                e.Children = new ObservableHashSet<OptionalAk2>(ReferenceEqualityComparer.Instance)
                                 {
                                     context.Set<OptionalAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid()),
                                     context.Set<OptionalAk2>().CreateProxy(e => e.AlternateId = Guid.NewGuid())
                                 };
 
                                 e.CompositeChildren =
-                                    new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance)
+                                    new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance)
                                     {
                                         context.Set<OptionalComposite2>().CreateProxy(), context.Set<OptionalComposite2>().CreateProxy()
                                     };
@@ -601,7 +601,7 @@ protected virtual object CreateFullGraph(DbContext context)
                             e.DerivedRoot = context.CreateProxy<Root>();
                         });
 
-                    e.RequiredCompositeChildren = new ObservableHashSet<RequiredComposite1>(LegacyReferenceEqualityComparer.Instance)
+                    e.RequiredCompositeChildren = new ObservableHashSet<RequiredComposite1>(ReferenceEqualityComparer.Instance)
                     {
                         context.Set<RequiredComposite1>().CreateProxy(
                             e =>
@@ -609,7 +609,7 @@ protected virtual object CreateFullGraph(DbContext context)
                                 e.Id = 1;
 
                                 e.CompositeChildren =
-                                    new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance)
+                                    new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance)
                                     {
                                         context.CreateProxy<OptionalOverlapping2>(e => e.Id = 1),
                                         context.CreateProxy<OptionalOverlapping2>(e => e.Id = 2)
@@ -621,7 +621,7 @@ protected virtual object CreateFullGraph(DbContext context)
                                 e.Id = 2;
 
                                 e.CompositeChildren =
-                                    new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance)
+                                    new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance)
                                     {
                                         context.CreateProxy<OptionalOverlapping2>(e => e.Id = 3),
                                         context.CreateProxy<OptionalOverlapping2>(e => e.Id = 4)
@@ -801,10 +801,10 @@ protected Root()
         public virtual Guid AlternateId { get; set; }
 
         public virtual IEnumerable<Required1> RequiredChildren { get; set; }
-            = new ObservableHashSet<Required1>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<Required1>(ReferenceEqualityComparer.Instance);
 
         public virtual IEnumerable<Optional1> OptionalChildren { get; set; }
-            = new ObservableHashSet<Optional1>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<Optional1>(ReferenceEqualityComparer.Instance);
 
         public virtual RequiredSingle1 RequiredSingle { get; set; }
 
@@ -821,10 +821,10 @@ protected Root()
         public virtual OptionalSingle1MoreDerived OptionalSingleMoreDerived { get; set; }
 
         public virtual IEnumerable<RequiredAk1> RequiredChildrenAk { get; set; }
-            = new ObservableHashSet<RequiredAk1>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<RequiredAk1>(ReferenceEqualityComparer.Instance);
 
         public virtual IEnumerable<OptionalAk1> OptionalChildrenAk { get; set; }
-            = new ObservableHashSet<OptionalAk1>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<OptionalAk1>(ReferenceEqualityComparer.Instance);
 
         public virtual RequiredSingleAk1 RequiredSingleAk { get; set; }
 
@@ -841,7 +841,7 @@ protected Root()
         public virtual OptionalSingleAk1MoreDerived OptionalSingleAkMoreDerived { get; set; }
 
         public virtual IEnumerable<RequiredComposite1> RequiredCompositeChildren { get; set; }
-            = new ObservableHashSet<RequiredComposite1>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<RequiredComposite1>(ReferenceEqualityComparer.Instance);
 
         public override bool Equals(object obj)
         {
@@ -866,7 +866,7 @@ protected Required1()
         public virtual Root Parent { get; set; }
 
         public virtual IEnumerable<Required2> Children { get; set; }
-            = new ObservableHashSet<Required2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<Required2>(ReferenceEqualityComparer.Instance);
 
         public override bool Equals(object obj)
         {
@@ -965,10 +965,10 @@ protected Optional1()
         public virtual Root Parent { get; set; }
 
         public virtual IEnumerable<Optional2> Children { get; set; }
-            = new ObservableHashSet<Optional2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<Optional2>(ReferenceEqualityComparer.Instance);
 
         public virtual ICollection<OptionalComposite2> CompositeChildren { get; set; }
-            = new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance);
 
         public override bool Equals(object obj)
         {
@@ -1323,10 +1323,10 @@ protected RequiredAk1()
         public virtual Root Parent { get; set; }
 
         public virtual IEnumerable<RequiredAk2> Children { get; set; }
-            = new ObservableHashSet<RequiredAk2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<RequiredAk2>(ReferenceEqualityComparer.Instance);
 
         public virtual IEnumerable<RequiredComposite2> CompositeChildren { get; set; }
-            = new ObservableHashSet<RequiredComposite2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<RequiredComposite2>(ReferenceEqualityComparer.Instance);
 
         public override bool Equals(object obj)
         {
@@ -1407,7 +1407,7 @@ public override bool Equals(object obj)
         }
 
         public virtual ICollection<OptionalOverlapping2> CompositeChildren { get; set; }
-            = new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance);
 
         public override int GetHashCode()
             => Id;
@@ -1504,10 +1504,10 @@ protected OptionalAk1()
         public virtual Root Parent { get; set; }
 
         public virtual IEnumerable<OptionalAk2> Children { get; set; }
-            = new ObservableHashSet<OptionalAk2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<OptionalAk2>(ReferenceEqualityComparer.Instance);
 
         public virtual ICollection<OptionalComposite2> CompositeChildren { get; set; }
-            = new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance);
 
         public override bool Equals(object obj)
         {
@@ -1956,7 +1956,7 @@ protected BadCustomer()
         public virtual int Status { get; set; }
 
         public virtual ICollection<BadOrder> BadOrders { get; set; }
-            = new ObservableHashSet<BadOrder>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<BadOrder>(ReferenceEqualityComparer.Instance);
     }
 
     public class BadOrder
@@ -2022,7 +2022,7 @@ public record RecordCar : RecordBase
     public record RecordPerson : RecordBase
     {
         public virtual ICollection<RecordCar> Vehicles { get; }
-            = new ObservableHashSet<RecordCar>(LegacyReferenceEqualityComparer.Instance);
+            = new ObservableHashSet<RecordCar>(ReferenceEqualityComparer.Instance);
     }
 
     protected DbContext CreateContext()
diff --git a/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesTestBaseOneToMany.cs b/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesTestBaseOneToMany.cs
index 3c0deebc6c6..36b15edf072 100644
--- a/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesTestBaseOneToMany.cs
+++ b/test/EFCore.Specification.Tests/GraphUpdates/ProxyGraphUpdatesTestBaseOneToMany.cs
@@ -463,7 +463,7 @@ public virtual void Reparent_to_different_one_to_many(ChangeMechanism changeMech
                 if (!useExistingParent)
                 {
                     newParent = context.CreateProxy<Optional1>(
-                        e => e.CompositeChildren = new ObservableHashSet<OptionalComposite2>(LegacyReferenceEqualityComparer.Instance));
+                        e => e.CompositeChildren = new ObservableHashSet<OptionalComposite2>(ReferenceEqualityComparer.Instance));
 
                     context.Set<Optional1>().Add(newParent);
                     context.SaveChanges();
@@ -607,7 +607,7 @@ public virtual void Reparent_one_to_many_overlapping(ChangeMechanism changeMecha
                         {
                             e.Id = 3;
                             e.Parent = context.Set<Root>().Single(IsTheRoot);
-                            e.CompositeChildren = new ObservableHashSet<OptionalOverlapping2>(LegacyReferenceEqualityComparer.Instance)
+                            e.CompositeChildren = new ObservableHashSet<OptionalOverlapping2>(ReferenceEqualityComparer.Instance)
                             {
                                 context.CreateProxy<OptionalOverlapping2>(e => e.Id = 5),
                                 context.CreateProxy<OptionalOverlapping2>(e => e.Id = 6)
diff --git a/test/EFCore.Specification.Tests/Query/NorthwindEFPropertyIncludeQueryTestBase.cs b/test/EFCore.Specification.Tests/Query/NorthwindEFPropertyIncludeQueryTestBase.cs
index e24b06ac008..8175f6dd065 100644
--- a/test/EFCore.Specification.Tests/Query/NorthwindEFPropertyIncludeQueryTestBase.cs
+++ b/test/EFCore.Specification.Tests/Query/NorthwindEFPropertyIncludeQueryTestBase.cs
@@ -64,7 +64,7 @@ var customer
                     .Include(c => EF.Property<Customer>(c, "Orders"))
                     .Single(c => c.CustomerID == "ALFKI");
 
-        Assert.Equal(orders, customer.Orders, LegacyReferenceEqualityComparer.Instance);
+        Assert.Equal(orders, customer.Orders, ReferenceEqualityComparer.Instance);
         Assert.Equal(6, customer.Orders.Count);
         Assert.True(orders.All(o => ReferenceEquals(o.Customer, customer)));
         Assert.Equal(6 + 1, context.ChangeTracker.Entries().Count());
diff --git a/test/EFCore.Specification.Tests/Query/NorthwindIncludeNoTrackingQueryTestBase.cs b/test/EFCore.Specification.Tests/Query/NorthwindIncludeNoTrackingQueryTestBase.cs
index 51f6634392f..9c72c3aa17e 100644
--- a/test/EFCore.Specification.Tests/Query/NorthwindIncludeNoTrackingQueryTestBase.cs
+++ b/test/EFCore.Specification.Tests/Query/NorthwindIncludeNoTrackingQueryTestBase.cs
@@ -129,7 +129,7 @@ var customer
                     .AsNoTracking()
                     .Single(c => c.CustomerID == "ALFKI");
 
-        Assert.NotEqual(orders, customer.Orders, LegacyReferenceEqualityComparer.Instance);
+        Assert.NotEqual(orders, customer.Orders, ReferenceEqualityComparer.Instance);
         Assert.Equal(6, customer.Orders.Count);
         Assert.True(customer.Orders.All(e => ReferenceEquals(e.Customer, customer)));
 
diff --git a/test/EFCore.Specification.Tests/Query/NorthwindIncludeQueryTestBase.cs b/test/EFCore.Specification.Tests/Query/NorthwindIncludeQueryTestBase.cs
index bcfb27cefdc..2fc8ee0b8fc 100644
--- a/test/EFCore.Specification.Tests/Query/NorthwindIncludeQueryTestBase.cs
+++ b/test/EFCore.Specification.Tests/Query/NorthwindIncludeQueryTestBase.cs
@@ -245,7 +245,7 @@ var customer
                     .Include(c => c.Orders)
                     .Single(c => c.CustomerID == "ALFKI");
 
-        Assert.Equal(orders, customer.Orders, LegacyReferenceEqualityComparer.Instance);
+        Assert.Equal(orders, customer.Orders, ReferenceEqualityComparer.Instance);
         Assert.Equal(6, customer.Orders.Count);
         Assert.True(orders.All(o => ReferenceEquals(o.Customer, customer)));
         Assert.Equal(6 + 1, context.ChangeTracker.Entries().Count());
diff --git a/test/EFCore.Specification.Tests/Query/NorthwindStringIncludeQueryTestBase.cs b/test/EFCore.Specification.Tests/Query/NorthwindStringIncludeQueryTestBase.cs
index 0db6bfb4c60..58dcc04c09c 100644
--- a/test/EFCore.Specification.Tests/Query/NorthwindStringIncludeQueryTestBase.cs
+++ b/test/EFCore.Specification.Tests/Query/NorthwindStringIncludeQueryTestBase.cs
@@ -89,7 +89,7 @@ var customer
                     .Include("Orders")
                     .Single(c => c.CustomerID == "ALFKI");
 
-        Assert.Equal(orders, customer.Orders, LegacyReferenceEqualityComparer.Instance);
+        Assert.Equal(orders, customer.Orders, ReferenceEqualityComparer.Instance);
         Assert.Equal(6, customer.Orders.Count);
         Assert.True(orders.All(o => ReferenceEquals(o.Customer, customer)));
         Assert.Equal(6 + 1, context.ChangeTracker.Entries().Count());
diff --git a/test/EFCore.Specification.Tests/SerializationTestBase.cs b/test/EFCore.Specification.Tests/SerializationTestBase.cs
index 6d63a5ca4fb..3c049fd6ec6 100644
--- a/test/EFCore.Specification.Tests/SerializationTestBase.cs
+++ b/test/EFCore.Specification.Tests/SerializationTestBase.cs
@@ -140,7 +140,7 @@ private static T RoundtripThroughNewtonsoftJson<T>(T collection, bool ignoreLoop
             ReferenceLoopHandling = ignoreLoops
                 ? ReferenceLoopHandling.Ignore
                 : ReferenceLoopHandling.Error,
-            EqualityComparer = LegacyReferenceEqualityComparer.Instance,
+            EqualityComparer = ReferenceEqualityComparer.Instance,
             Formatting = writeIndented
                 ? Formatting.Indented
                 : Formatting.None
diff --git a/test/EFCore.Tests/ChangeTracking/Internal/OwnedFixupTest.cs b/test/EFCore.Tests/ChangeTracking/Internal/OwnedFixupTest.cs
index 5c166578b6f..4138fd1fcc0 100644
--- a/test/EFCore.Tests/ChangeTracking/Internal/OwnedFixupTest.cs
+++ b/test/EFCore.Tests/ChangeTracking/Internal/OwnedFixupTest.cs
@@ -5583,8 +5583,8 @@ private static ICollection<T> CreateChildCollection<T>(CollectionType collection
             CollectionType.SortedSet => new SortedSet<T> { dependent },
             CollectionType.Collection => new Collection<T> { dependent },
             CollectionType.ObservableCollection => new ObservableCollection<T> { dependent },
-            CollectionType.ObservableHashSet => new ObservableHashSet<T>(LegacyReferenceEqualityComparer.Instance) { dependent },
-            _ => new HashSet<T>(LegacyReferenceEqualityComparer.Instance) { dependent }
+            CollectionType.ObservableHashSet => new ObservableHashSet<T>(ReferenceEqualityComparer.Instance) { dependent },
+            _ => new HashSet<T>(ReferenceEqualityComparer.Instance) { dependent }
         };
 
     private void AssertFixup(DbContext context, Action asserts)
diff --git a/test/EFCore.Tests/ChangeTracking/ObservableHashSetTest.cs b/test/EFCore.Tests/ChangeTracking/ObservableHashSetTest.cs
index a3d8d8a79dc..744d43f3c96 100644
--- a/test/EFCore.Tests/ChangeTracking/ObservableHashSetTest.cs
+++ b/test/EFCore.Tests/ChangeTracking/ObservableHashSetTest.cs
@@ -20,8 +20,8 @@ public void Can_construct()
             new ObservableHashSet<int>().Comparer);
 
         Assert.Same(
-            LegacyReferenceEqualityComparer.Instance,
-            new ObservableHashSet<object>(LegacyReferenceEqualityComparer.Instance).Comparer);
+            ReferenceEqualityComparer.Instance,
+            new ObservableHashSet<object>(ReferenceEqualityComparer.Instance).Comparer);
 
         var testData1 = CreateTestData();
 
@@ -32,8 +32,8 @@ public void Can_construct()
 
         var testData2 = CreateTestData().Cast<object>();
 
-        var rh2 = new HashSet<object>(testData2, LegacyReferenceEqualityComparer.Instance);
-        var ohs2 = new ObservableHashSet<object>(testData2, LegacyReferenceEqualityComparer.Instance);
+        var rh2 = new HashSet<object>(testData2, ReferenceEqualityComparer.Instance);
+        var ohs2 = new ObservableHashSet<object>(testData2, ReferenceEqualityComparer.Instance);
         Assert.Equal(rh2.OrderBy(i => i), ohs2.OrderBy(i => i));
         Assert.Same(rh2.Comparer, ohs2.Comparer);
     }
diff --git a/test/EFCore.Tests/Extensions/QueryableExtensionsTest.cs b/test/EFCore.Tests/Extensions/QueryableExtensionsTest.cs
index c8ecf1cf3f7..843e83ea9a6 100644
--- a/test/EFCore.Tests/Extensions/QueryableExtensionsTest.cs
+++ b/test/EFCore.Tests/Extensions/QueryableExtensionsTest.cs
@@ -303,12 +303,12 @@ public async Task Extension_methods_throw_on_non_async_source()
         await SourceNonAsyncQueryableTest(() => Source<decimal?>().SumAsync(e => e));
         await SourceNonAsyncEnumerableTest<int>(() => Source().ToDictionaryAsync(e => e));
         await SourceNonAsyncEnumerableTest<int>(() => Source().ToDictionaryAsync(e => e, e => e));
-        await SourceNonAsyncEnumerableTest<int>(() => Source().ToDictionaryAsync(e => e, LegacyReferenceEqualityComparer.Instance));
-        await SourceNonAsyncEnumerableTest<int>(() => Source().ToDictionaryAsync(e => e, LegacyReferenceEqualityComparer.Instance));
+        await SourceNonAsyncEnumerableTest<int>(() => Source().ToDictionaryAsync(e => e, ReferenceEqualityComparer.Instance));
+        await SourceNonAsyncEnumerableTest<int>(() => Source().ToDictionaryAsync(e => e, ReferenceEqualityComparer.Instance));
         await SourceNonAsyncEnumerableTest<int>(
-            () => Source().ToDictionaryAsync(e => e, e => e, LegacyReferenceEqualityComparer.Instance));
+            () => Source().ToDictionaryAsync(e => e, e => e, ReferenceEqualityComparer.Instance));
         await SourceNonAsyncEnumerableTest<int>(
-            () => Source().ToDictionaryAsync(e => e, e => e, LegacyReferenceEqualityComparer.Instance, new CancellationToken()));
+            () => Source().ToDictionaryAsync(e => e, e => e, ReferenceEqualityComparer.Instance, new CancellationToken()));
         await SourceNonAsyncEnumerableTest<int>(() => Source().ToListAsync());
 
         Assert.Equal(