Use covariant return for synthesized record clone (#53404)

dotnet · Jul 11, 2021 · 8eb425e · 8eb425e
1 parent 26cf667
commit 8eb425e
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Showing 2 changed files with 259 additions and 40 deletions.
diff --git a/src/Compilers/CSharp/Portable/Symbols/Synthesized/Records/SynthesizedRecordClone.cs b/src/Compilers/CSharp/Portable/Symbols/Synthesized/Records/SynthesizedRecordClone.cs
@@ -97,8 +97,8 @@ static bool modifiersAreValid(DeclarationModifiers modifiers)
 
         protected override (TypeWithAnnotations ReturnType, ImmutableArray<ParameterSymbol> Parameters, bool IsVararg, ImmutableArray<TypeParameterConstraintClause> DeclaredConstraintsForOverrideOrImplementation) MakeParametersAndBindReturnType(BindingDiagnosticBag diagnostics)
         {
-            return (ReturnType: VirtualCloneInBase() is { } baseClone ?
-                                     baseClone.ReturnTypeWithAnnotations : // Use covariant returns when available
+            return (ReturnType: !ContainingAssembly.RuntimeSupportsCovariantReturnsOfClasses && VirtualCloneInBase() is { } baseClone ?
+                                     baseClone.ReturnTypeWithAnnotations :
                                      TypeWithAnnotations.Create(isNullableEnabled: true, ContainingType),
                     Parameters: ImmutableArray<ParameterSymbol>.Empty,
                     IsVararg: false,