Align addition of a synthesized override of object.GetHashCode() in r…

…ecords with the latest design. (#45518)

Related to #45296.

From specification:
The record type includes a synthesized override of object.GetHashCode(). The method can be declared explicitly. It is an error if the explicit declaration is sealed unless the record type is sealed.

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -6280,4 +6280,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_DoesNotOverrideMethodFromObject" xml:space="preserve">
     <value>'{0}' does not override the method from 'object'.</value>
   </data>
+  <data name="ERR_SealedGetHashCodeInRecord" xml:space="preserve">
+    <value>'{0}' cannot be sealed because containing 'record' is not sealed.</value>
+  </data>
 </root>

src/Compilers/CSharp/Portable/Errors/ErrorCode.cs

@@ -1855,6 +1855,7 @@ internal enum ErrorCode
         ERR_NoCopyConstructorInBaseType = 8867,
         ERR_CopyConstructorMustInvokeBaseCopyConstructor = 8868,
         ERR_DoesNotOverrideMethodFromObject = 8869,
+        ERR_SealedGetHashCodeInRecord = 8870,
 
         #endregion diagnostics introduced for C# 9.0
         // Note: you will need to re-generate compiler code after adding warnings (eng\generate-compiler-code.cmd)

src/Compilers/CSharp/Portable/Symbols/Source/SourceMemberContainerSymbol.cs

@@ -2974,6 +2974,8 @@ private void AddSynthesizedRecordMembersIfNecessary(MembersAndInitializersBuilde
                 }
             }
 
+            CSharpCompilation compilation = this.DeclaringCompilation;
+
             // Positional record
             if (!(paramList is null))
             {
@@ -3009,7 +3011,7 @@ private void AddSynthesizedRecordMembersIfNecessary(MembersAndInitializersBuilde
 
 
             // We put synthesized record members first so that errors about conflicts show up on user-defined members rather than all
-            // go to the record declaration
+            // going to the record declaration
             members.AddRange(builder.NonTypeNonIndexerMembers);
             builder.NonTypeNonIndexerMembers.Free();
             builder.NonTypeNonIndexerMembers = members;
@@ -3133,12 +3135,32 @@ void addObjectEquals(MethodSymbol thisEquals)
 
             void addHashCode(PropertySymbol equalityContract)
             {
-                var hashCode = new SynthesizedRecordGetHashCode(this, equalityContract, memberOffset: members.Count);
-                if (!memberSignatures.ContainsKey(hashCode))
-                {
-                    // https://github.com/dotnet/roslyn/issues/44617: Don't add if the overridden method is sealed
+                var targetMethod = new SignatureOnlyMethodSymbol(
+                    WellKnownMemberNames.ObjectGetHashCode,
+                    this,
+                    MethodKind.Ordinary,
+                    Cci.CallingConvention.HasThis,
+                    ImmutableArray<TypeParameterSymbol>.Empty,
+                    ImmutableArray<ParameterSymbol>.Empty,
+                    RefKind.None,
+                    isInitOnly: false,
+                    TypeWithAnnotations.Create(compilation.GetSpecialType(SpecialType.System_Int32)),
+                    ImmutableArray<CustomModifier>.Empty,
+                    ImmutableArray<MethodSymbol>.Empty);
+
+                if (!memberSignatures.TryGetValue(targetMethod, out Symbol? contender))
+                {
+                    var hashCode = new SynthesizedRecordGetHashCode(this, equalityContract, memberOffset: members.Count, diagnostics);
                     members.Add(hashCode);
                 }
+                else
+                {
+                    var method = (MethodSymbol)contender;
+                    if (!SynthesizedRecordObjectMethod.VerifyOerridesMethodFromObject(method, diagnostics) && method.IsSealed && !IsSealed)
+                    {
+                        diagnostics.Add(ErrorCode.ERR_SealedGetHashCodeInRecord, method.Locations[0], method);
+                    }
+                }
             }
 
             PropertySymbol addEqualityContract()

src/Compilers/CSharp/Portable/Symbols/Synthesized/Records/SynthesizedRecordGetHashCode.cs

@@ -12,106 +12,31 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.Symbols
 {
-    internal sealed class SynthesizedRecordGetHashCode : SynthesizedInstanceMethodSymbol
+    internal sealed class SynthesizedRecordGetHashCode : SynthesizedRecordObjectMethod
     {
-        private readonly int _memberOffset;
         private readonly PropertySymbol _equalityContract;
 
-        public override NamedTypeSymbol ContainingType { get; }
-
-        public SynthesizedRecordGetHashCode(NamedTypeSymbol containingType, PropertySymbol equalityContract, int memberOffset)
+        public SynthesizedRecordGetHashCode(SourceMemberContainerTypeSymbol containingType, PropertySymbol equalityContract, int memberOffset, DiagnosticBag diagnostics)
+            : base(containingType, WellKnownMemberNames.ObjectGetHashCode, memberOffset, diagnostics)
         {
-            _memberOffset = memberOffset;
-            ContainingType = containingType;
             _equalityContract = equalityContract;
         }
 
-        public override string Name => "GetHashCode";
-
-        public override ImmutableArray<ParameterSymbol> Parameters => ImmutableArray<ParameterSymbol>.Empty;
-
-        public override MethodKind MethodKind => MethodKind.Ordinary;
-
-        public override int Arity => 0;
-
-        public override bool IsExtensionMethod => false;
-
-        public override bool HidesBaseMethodsByName => false;
-
-        public override bool IsVararg => false;
-
-        public override bool ReturnsVoid => false;
-
-        public override bool IsAsync => false;
-
-        public override RefKind RefKind => RefKind.None;
-
-        internal override LexicalSortKey GetLexicalSortKey() => LexicalSortKey.GetSynthesizedMemberKey(_memberOffset);
-
         public override TypeWithAnnotations ReturnTypeWithAnnotations => TypeWithAnnotations.Create(
             isNullableEnabled: true,
             ContainingType.DeclaringCompilation.GetSpecialType(SpecialType.System_Int32));
 
-        public override FlowAnalysisAnnotations ReturnTypeFlowAnalysisAnnotations => FlowAnalysisAnnotations.None;
-
-        public override ImmutableHashSet<string> ReturnNotNullIfParameterNotNull => ImmutableHashSet<string>.Empty;
-
-        public override ImmutableArray<TypeWithAnnotations> TypeArgumentsWithAnnotations
-            => ImmutableArray<TypeWithAnnotations>.Empty;
-
-        public override ImmutableArray<TypeParameterSymbol> TypeParameters => ImmutableArray<TypeParameterSymbol>.Empty;
-
-        public override ImmutableArray<MethodSymbol> ExplicitInterfaceImplementations => ImmutableArray<MethodSymbol>.Empty;
-
-        public override ImmutableArray<CustomModifier> RefCustomModifiers => ImmutableArray<CustomModifier>.Empty;
-
-        public override Symbol? AssociatedSymbol => null;
-
-        public override Symbol ContainingSymbol => ContainingType;
-
-        public override ImmutableArray<Location> Locations => ContainingType.Locations;
-
-        public override Accessibility DeclaredAccessibility => Accessibility.Public;
-
-        public override bool IsStatic => false;
-
-        public override bool IsVirtual => false;
-
-        public override bool IsOverride => true;
-
-        public override bool IsAbstract => false;
-
-        public override bool IsSealed => false;
-
-        public override bool IsExtern => false;
-
-        internal override bool HasSpecialName => false;
-
-        internal override MethodImplAttributes ImplementationAttributes => MethodImplAttributes.Managed;
-
-        internal override bool HasDeclarativeSecurity => false;
-
-        internal override MarshalPseudoCustomAttributeData? ReturnValueMarshallingInformation => null;
-
-        internal override bool RequiresSecurityObject => false;
-
-        internal override CallingConvention CallingConvention => CallingConvention.HasThis;
-
-        internal override bool GenerateDebugInfo => false;
-
-        public override DllImportData? GetDllImportData() => null;
-
-        internal override ImmutableArray<string> GetAppliedConditionalSymbols()
-            => ImmutableArray<string>.Empty;
-
-        internal override IEnumerable<SecurityAttribute> GetSecurityInformation()
-            => Array.Empty<SecurityAttribute>();
-
-        internal override bool IsMetadataNewSlot(bool ignoreInterfaceImplementationChanges = false) => false;
-
-        internal override bool IsMetadataVirtual(bool ignoreInterfaceImplementationChanges = false) => true;
+        protected override (TypeWithAnnotations ReturnType, ImmutableArray<ParameterSymbol> Parameters, bool IsVararg, ImmutableArray<TypeParameterConstraintClause> DeclaredConstraintsForOverrideOrImplement) MakeParametersAndBindReturnType(DiagnosticBag diagnostics)
+        {
+            var compilation = DeclaringCompilation;
+            var location = ReturnTypeLocation;
+            return (ReturnType: TypeWithAnnotations.Create(Binder.GetSpecialType(compilation, SpecialType.System_Int32, location, diagnostics)),
+                    Parameters: ImmutableArray<ParameterSymbol>.Empty,
+                    IsVararg: false,
+                    DeclaredConstraintsForOverrideOrImplement: ImmutableArray<TypeParameterConstraintClause>.Empty);
+        }
 
-        internal override bool SynthesizesLoweredBoundBody => true;
+        protected override int GetParameterCountFromSyntax() => 0;
 
         internal override void GenerateMethodBody(TypeCompilationState compilationState, DiagnosticBag diagnostics)
         {

src/Compilers/CSharp/Portable/Symbols/Synthesized/Records/SynthesizedRecordObjEquals.cs

@@ -5,7 +5,6 @@
 #nullable enable
 
 using System.Collections.Immutable;
-using System.Diagnostics;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp.Symbols
@@ -15,18 +14,11 @@ internal sealed class SynthesizedRecordObjEquals : SynthesizedRecordObjectMethod
         private readonly MethodSymbol _typedRecordEquals;
 
         public SynthesizedRecordObjEquals(SourceMemberContainerTypeSymbol containingType, MethodSymbol typedRecordEquals, int memberOffset, DiagnosticBag diagnostics)
-            : base(containingType, "Equals", memberOffset, diagnostics)
+            : base(containingType, WellKnownMemberNames.ObjectEquals, memberOffset, diagnostics)
         {
             _typedRecordEquals = typedRecordEquals;
         }
 
-        protected override DeclarationModifiers MakeDeclarationModifiers(DeclarationModifiers allowedModifiers, DiagnosticBag diagnostics)
-        {
-            const DeclarationModifiers result = DeclarationModifiers.Public | DeclarationModifiers.Override;
-            Debug.Assert((result & ~allowedModifiers) == 0);
-            return result;
-        }
-
         protected override (TypeWithAnnotations ReturnType, ImmutableArray<ParameterSymbol> Parameters, bool IsVararg, ImmutableArray<TypeParameterConstraintClause> DeclaredConstraintsForOverrideOrImplement) MakeParametersAndBindReturnType(DiagnosticBag diagnostics)
         {
             var compilation = DeclaringCompilation;

src/Compilers/CSharp/Portable/Symbols/Synthesized/Records/SynthesizedRecordObjectMethod.cs

@@ -4,6 +4,8 @@
 
 #nullable enable
 
+using System.Diagnostics;
+
 namespace Microsoft.CodeAnalysis.CSharp.Symbols
 {
     /// <summary>
@@ -16,25 +18,49 @@ protected SynthesizedRecordObjectMethod(SourceMemberContainerTypeSymbol containi
         {
         }
 
+        protected sealed override DeclarationModifiers MakeDeclarationModifiers(DeclarationModifiers allowedModifiers, DiagnosticBag diagnostics)
+        {
+            const DeclarationModifiers result = DeclarationModifiers.Public | DeclarationModifiers.Override;
+            Debug.Assert((result & ~allowedModifiers) == 0);
+            return result;
+        }
+
         protected sealed override void MethodChecks(DiagnosticBag diagnostics)
         {
             base.MethodChecks(diagnostics);
+            VerifyOerridesMethodFromObject(this, diagnostics);
+        }
 
-            var overridden = OverriddenMethod?.OriginalDefinition;
+        /// <summary>
+        /// Returns true if reported an error
+        /// </summary>
+        internal static bool VerifyOerridesMethodFromObject(MethodSymbol overriding, DiagnosticBag diagnostics)
+        {
+            bool reportAnError = false;
 
-            if (overridden is null || (overridden is SynthesizedRecordObjEquals && overridden.DeclaringCompilation == DeclaringCompilation))
+            if (!overriding.IsOverride)
             {
-                return;
+                reportAnError = true;
             }
+            else
+            {
+                var overridden = overriding.OverriddenMethod?.OriginalDefinition;
 
-            MethodSymbol leastOverridden = GetLeastOverriddenMethod(accessingTypeOpt: null);
+                if (overridden is object && !(overridden.ContainingType is SourceMemberContainerTypeSymbol { IsRecord: true } && overridden.ContainingModule == overriding.ContainingModule))
+                {
+                    MethodSymbol leastOverridden = overriding.GetLeastOverriddenMethod(accessingTypeOpt: null);
 
-            if (leastOverridden is object &&
-                leastOverridden.ReturnType.SpecialType == ReturnType.SpecialType &&
-                leastOverridden.ContainingType.SpecialType != SpecialType.System_Object)
+                    reportAnError = leastOverridden.ReturnType.SpecialType == overriding.ReturnType.SpecialType &&
+                                    leastOverridden.ContainingType.SpecialType != SpecialType.System_Object;
+                }
+            }
+
+            if (reportAnError)
             {
-                diagnostics.Add(ErrorCode.ERR_DoesNotOverrideMethodFromObject, Locations[0], this);
+                diagnostics.Add(ErrorCode.ERR_DoesNotOverrideMethodFromObject, overriding.Locations[0], overriding);
             }
+
+            return reportAnError;
         }
     }
 }

src/Compilers/CSharp/Portable/xlf/CSharpResources.cs.xlf

@@ -662,6 +662,11 @@
         <target state="translated">Cílový modul runtime nepodporuje pro člena rozhraní přístupnost na úrovni Protected, Protected internal nebo Private protected.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>

src/Compilers/CSharp/Portable/xlf/CSharpResources.de.xlf

@@ -662,6 +662,11 @@
         <target state="translated">Die Zugriffsoptionen "protected", "protected internal" oder "private protected" werden von der Zielruntime für einen Member einer Schnittstelle nicht unterstützt.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>

src/Compilers/CSharp/Portable/xlf/CSharpResources.es.xlf

@@ -662,6 +662,11 @@
         <target state="translated">El entorno de ejecución de destino no admite la accesibilidad protegida, protegida interna o protegida privada para un miembro de una interfaz.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>

src/Compilers/CSharp/Portable/xlf/CSharpResources.fr.xlf

@@ -662,6 +662,11 @@
         <target state="translated">Le runtime cible ne prend pas en charge l'accessibilité 'protected', 'protected internal' ou 'private protected' d'un membre d'interface.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>

src/Compilers/CSharp/Portable/xlf/CSharpResources.it.xlf

@@ -662,6 +662,11 @@
         <target state="translated">Il runtime di destinazione non supporta l'accessibilità 'protected', 'protected internal' o 'private protected' per un membro di un'interfaccia.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>

src/Compilers/CSharp/Portable/xlf/CSharpResources.ja.xlf

@@ -662,6 +662,11 @@
         <target state="translated">ターゲット ランタイムは、インターフェイスのメンバーに対して 'protected'、'protected internal'、'private protected' アクセシビリティをサポートしていません。</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>

src/Compilers/CSharp/Portable/xlf/CSharpResources.ko.xlf

@@ -662,6 +662,11 @@
         <target state="translated">대상 런타임이 인터페이스 멤버의 'protected', 'protected internal' 또는 'private protected' 접근성을 지원하지 않습니다.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>

src/Compilers/CSharp/Portable/xlf/CSharpResources.pl.xlf

@@ -662,6 +662,11 @@
         <target state="translated">Docelowe środowisko uruchomieniowe nie obsługuje specyfikatorów dostępu „protected”, „protected internal” i „private protected” dla składowej interfejsu.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+        <source>'{0}' cannot be sealed because containing 'record' is not sealed.</source>
+        <target state="new">'{0}' cannot be sealed because containing 'record' is not sealed.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_SimpleProgramDisallowsMainType">
         <source>Cannot specify /main if there is a compilation unit with top-level statements.</source>
         <target state="new">Cannot specify /main if there is a compilation unit with top-level statements.</target>