Merge pull request #38159 from jasonmalinowski/fix-generategethashcode

Update Generate Equals and GetHashCode to handle nullable members

src/EditorFeatures/CSharpTest/GenerateFromMembers/GenerateEqualsAndGetHashCodeFromMembers/GenerateEqualsAndGetHashCodeFromMembersTests.cs

@@ -22,9 +22,6 @@ public class GenerateEqualsAndGetHashCodeFromMembersTests : AbstractCSharpCodeAc
         private static readonly TestParameters CSharp6 =
             new TestParameters(parseOptions: TestOptions.Regular.WithLanguageVersion(LanguageVersion.CSharp6));
 
-        private static readonly TestParameters CSharp8 =
-            new TestParameters(parseOptions: TestOptions.Regular.WithLanguageVersion(LanguageVersion.CSharp8));
-
         protected override CodeRefactoringProvider CreateCodeRefactoringProvider(Workspace workspace, TestParameters parameters)
             => new GenerateEqualsAndGetHashCodeFromMembersCodeRefactoringProvider((IPickMembersService)parameters.fixProviderData);
 
@@ -88,6 +85,45 @@ public override bool Equals(object obj)
 parameters: CSharp6);
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateEqualsAndGetHashCode)]
+        public async Task TestNullableReferenceIEquatable()
+        {
+            await TestInRegularAndScript1Async(
+@"#nullable enable
+
+using System;
+using System.Collections.Generic;
+
+class S : IEquatable<S> { }
+
+class Program
+{
+    [|S? a;|]
+}",
+@"#nullable enable
+
+using System;
+using System.Collections.Generic;
+
+class S : IEquatable<S> { }
+
+class Program
+{
+    S? a;
+
+    public override bool Equals(object? obj)
+    {
+        return obj is Program program &&
+               EqualityComparer<S?>.Default.Equals(a, program.a);
+    }
+
+    public override int GetHashCode()
+    {
+        return -1757793268 + EqualityComparer<S?>.Default.GetHashCode(a);
+    }
+}", index: 1);
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateEqualsAndGetHashCode)]
         public async Task TestValueIEquatable()
         {
@@ -422,8 +458,7 @@ public override bool Equals(object? obj)
         return obj is Program program &&
                a == program.a;
     }
-}",
-parameters: CSharp8);
+}");
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateEqualsAndGetHashCode)]

src/Workspaces/Core/Portable/Shared/Extensions/SyntaxGeneratorExtensions_CreateEqualsMethod.cs

@@ -365,7 +365,7 @@ private static bool IsPrimitiveValueType(ITypeSymbol typeSymbol)
             ITypeSymbol type)
         {
             var equalityComparerType = compilation.EqualityComparerOfTType();
-            var constructedType = equalityComparerType.Construct(type);
+            var constructedType = equalityComparerType.ConstructWithNullability(type);
             return factory.MemberAccessExpression(
                 factory.TypeExpression(constructedType),
                 factory.IdentifierName(DefaultName));
@@ -375,8 +375,8 @@ private static ITypeSymbol GetType(Compilation compilation, ISymbol symbol)
         {
             switch (symbol)
             {
-                case IFieldSymbol field: return field.Type;
-                case IPropertySymbol property: return property.Type;
+                case IFieldSymbol field: return field.GetTypeWithAnnotatedNullability();
+                case IPropertySymbol property: return property.GetTypeWithAnnotatedNullability();
                 default: return compilation.GetSpecialType(SpecialType.System_Object);
             }
         }