Record-structs: Address some PROTOTYPE markers

src/Compilers/CSharp/CSharpAnalyzerDriver/CSharpDeclarationComputer.cs

@@ -97,8 +97,6 @@ private static void ComputeDeclarations(
 
                         return;
                     }
-
-                // PROTOTYPE(record-structs): update for record structs
                 case SyntaxKind.RecordDeclaration:
                     {
                         if (associatedSymbol is IMethodSymbol ctor)
@@ -117,6 +115,20 @@ private static void ComputeDeclarations(
                             return;
                         }
 
+                        goto case SyntaxKind.ClassDeclaration;
+                    }
+                case SyntaxKind.RecordStructDeclaration:
+                    {
+                        if (associatedSymbol is IMethodSymbol ctor)
+                        {
+                            var recordDeclaration = (RecordStructDeclarationSyntax)node;
+                            Debug.Assert(ctor.MethodKind == MethodKind.Constructor && recordDeclaration.ParameterList is object);
+
+                            var codeBlocks = GetParameterListInitializersAndAttributes(recordDeclaration.ParameterList);
+                            builder.Add(GetDeclarationInfo(node, associatedSymbol, codeBlocks));
+                            return;
+                        }
+
                         goto case SyntaxKind.ClassDeclaration;
                     }
                 case SyntaxKind.ClassDeclaration:

src/Compilers/CSharp/Portable/Compilation/SyntaxTreeSemanticModel.cs

@@ -181,7 +181,6 @@ internal override IOperation GetOperationWorker(CSharpSyntaxNode node, Cancellat
                 case AccessorDeclarationSyntax accessor:
                     model = (accessor.Body != null || accessor.ExpressionBody != null) ? GetOrAddModel(node) : null;
                     break;
-                // PROTOTYPE(record-structs): update for record structs
                 case RecordDeclarationSyntax { ParameterList: { }, PrimaryConstructorBaseType: { } } recordDeclaration when TryGetSynthesizedRecordConstructor(recordDeclaration) is SynthesizedRecordConstructor:
                     model = GetOrAddModel(recordDeclaration);
                     break;
@@ -805,7 +804,6 @@ private MemberSemanticModel GetMemberModel(int position)
                             !LookupPosition.IsInConstructorParameterScope(position, constructorDecl) &&
                             !LookupPosition.IsInParameterList(position, constructorDecl);
                         break;
-                    // PROTOTYPE(record-structs): update for record structs
                     case SyntaxKind.RecordDeclaration:
                         {
                             var recordDecl = (RecordDeclarationSyntax)memberDecl;
@@ -875,7 +873,6 @@ internal override MemberSemanticModel GetMemberModel(SyntaxNode node)
                                    GetOrAddModel(constructorDecl) : null;
                         }
 
-                    // PROTOTYPE(record-structs): update for record structs
                     case SyntaxKind.RecordDeclaration:
                         {
                             var recordDecl = (RecordDeclarationSyntax)memberDecl;
@@ -1094,7 +1091,6 @@ private MemberSemanticModel CreateMemberModel(CSharpSyntaxNode node)
                         return createMethodBodySemanticModel(memberDecl, symbol);
                     }
 
-                // PROTOTYPE(record-structs): update for record structs
                 case SyntaxKind.RecordDeclaration:
                     {
                         SynthesizedRecordConstructor symbol = TryGetSynthesizedRecordConstructor((RecordDeclarationSyntax)node);
@@ -1259,8 +1255,9 @@ MemberSemanticModel createMethodBodySemanticModel(CSharpSyntaxNode memberDecl, S
             }
         }
 
-        private SynthesizedRecordConstructor TryGetSynthesizedRecordConstructor(RecordDeclarationSyntax node)
+        private SynthesizedRecordConstructor TryGetSynthesizedRecordConstructor(TypeDeclarationSyntax node)
         {
+            Debug.Assert(node is RecordDeclarationSyntax or RecordStructDeclarationSyntax);
             NamedTypeSymbol recordType = GetDeclaredType(node);
             var symbol = recordType.GetMembersUnordered().OfType<SynthesizedRecordConstructor>().SingleOrDefault();
 
@@ -2026,11 +2023,14 @@ private ParameterSymbol GetMethodParameterSymbol(
 
             MethodSymbol method;
 
-            // PROTOTYPE(record-structs): update for record structs
             if (memberDecl is RecordDeclarationSyntax recordDecl && recordDecl.ParameterList == paramList)
             {
                 method = TryGetSynthesizedRecordConstructor(recordDecl);
             }
+            else if (memberDecl is RecordStructDeclarationSyntax recordStructDecl && recordStructDecl.ParameterList == paramList)
+            {
+                method = TryGetSynthesizedRecordConstructor(recordStructDecl);
+            }
             else
             {
                 method = (GetDeclaredSymbol(memberDecl, cancellationToken) as IMethodSymbol).GetSymbol();
@@ -2374,7 +2374,6 @@ internal override Symbol RemapSymbolIfNecessaryCore(Symbol symbol)
 
         internal override Func<SyntaxNode, bool> GetSyntaxNodesToAnalyzeFilter(SyntaxNode declaredNode, ISymbol declaredSymbol)
         {
-            // PROTOTYPE(record-structs): update for record structs
             switch (declaredNode)
             {
                 case CompilationUnitSyntax unit when SimpleProgramNamedTypeSymbol.GetSimpleProgramEntryPoint(Compilation, unit, fallbackToMainEntryPoint: false) is SynthesizedSimpleProgramEntryPointSymbol entryPoint:
@@ -2436,6 +2435,33 @@ internal override Func<SyntaxNode, bool> GetSyntaxNodesToAnalyzeFilter(SyntaxNod
                     }
                     break;
 
+                case RecordStructDeclarationSyntax recordStructDeclaration when TryGetSynthesizedRecordConstructor(recordStructDeclaration) is SynthesizedRecordConstructor ctor:
+                    switch (declaredSymbol.Kind)
+                    {
+                        case SymbolKind.Method:
+                            Debug.Assert((object)declaredSymbol.GetSymbol() == (object)ctor);
+                            return (node) =>
+                            {
+                                // Accept only nodes that either match, or above/below of a 'parameter list'.
+                                if (node.Parent == recordStructDeclaration)
+                                {
+                                    return node == recordStructDeclaration.ParameterList;
+                                }
+
+                                return true;
+                            };
+
+                        case SymbolKind.NamedType:
+                            Debug.Assert((object)declaredSymbol.GetSymbol() == (object)ctor.ContainingSymbol);
+                            // Accept nodes that do not match a 'parameter list'.
+                            return (node) => node != recordStructDeclaration.ParameterList;
+
+                        default:
+                            ExceptionUtilities.UnexpectedValue(declaredSymbol.Kind);
+                            break;
+                    }
+                    break;
+
                 case PrimaryConstructorBaseTypeSyntax { Parent: BaseListSyntax { Parent: RecordDeclarationSyntax recordDeclaration } } baseType
                         when recordDeclaration.PrimaryConstructorBaseType == declaredNode && TryGetSynthesizedRecordConstructor(recordDeclaration) is SynthesizedRecordConstructor ctor:
                     if ((object)declaredSymbol.GetSymbol() == (object)ctor)
@@ -2448,6 +2474,10 @@ internal override Func<SyntaxNode, bool> GetSyntaxNodesToAnalyzeFilter(SyntaxNod
                 case ParameterSyntax param when declaredSymbol.Kind == SymbolKind.Property && param.Parent?.Parent is RecordDeclarationSyntax recordDeclaration && recordDeclaration.ParameterList == param.Parent:
                     Debug.Assert(declaredSymbol.GetSymbol() is SynthesizedRecordPropertySymbol);
                     return (node) => false;
+
+                case ParameterSyntax param when declaredSymbol.Kind == SymbolKind.Property && param.Parent?.Parent is RecordStructDeclarationSyntax recordStructDeclaration && recordStructDeclaration.ParameterList == param.Parent:
+                    Debug.Assert(declaredSymbol.GetSymbol() is SynthesizedRecordPropertySymbol);
+                    return (node) => false;
             }
 
             return null;

src/Compilers/CSharp/Portable/Declarations/DeclarationKind.cs

@@ -23,7 +23,6 @@ internal enum DeclarationKind : byte
         Submission,
         ImplicitClass,
         SimpleProgram,
-        // PROTOTYPE(record-structs): rename to RecordClass?
         Record,
         RecordStruct
     }

src/Compilers/CSharp/Portable/Symbols/Metadata/PE/PENamedTypeSymbol.cs

@@ -565,7 +565,7 @@ internal override bool IsRecord
             }
         }
 
-        // PROTOTYPE(record-structs): update for record structs (is there a way to recognize a record struct from PE?)
+        // Record structs get erased when emitted to metadata
         internal override bool IsRecordStruct => false;
 
         public override Accessibility DeclaredAccessibility

src/Compilers/CSharp/Portable/Symbols/PublicModel/TypeSymbol.cs

@@ -172,6 +172,6 @@ ImmutableArray<SymbolDisplayPart> ITypeSymbol.ToMinimalDisplayParts(SemanticMode
 
         bool ITypeSymbol.IsReadOnly => UnderlyingTypeSymbol.IsReadOnly;
 
-        bool ITypeSymbol.IsRecord => UnderlyingTypeSymbol.IsRecord;
+        bool ITypeSymbol.IsRecord => UnderlyingTypeSymbol.IsRecord || UnderlyingTypeSymbol.IsRecordStruct;
     }
 }

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

@@ -1331,7 +1331,6 @@ public sealed override ImmutableArray<Symbol> GetMembers(string name)
             return ImmutableArray<Symbol>.Empty;
         }
 
-        // PROTOTYPE(record-structs): update for record structs
         /// <remarks>
         /// For source symbols, there can only be a valid clone method if this is a record, which is a
         /// simple syntax check. This will need to change when we generalize cloning, but it's a good
@@ -1512,7 +1511,6 @@ internal void AssertMemberExposure(Symbol member, bool forDiagnostics = false)
             var declared = Volatile.Read(ref _lazyDeclaredMembersAndInitializers);
             Debug.Assert(declared != DeclaredMembersAndInitializers.UninitializedSentinel);
 
-            // PROTOTYPE(record-structs): update for record structs
             if ((declared is object && (declared.NonTypeMembers.Contains(m => m == (object)member) || declared.RecordPrimaryConstructor == (object)member)) ||
                 Volatile.Read(ref _lazyMembersAndInitializers)?.NonTypeMembers.Contains(m => m == (object)member) == true)
             {
@@ -2969,7 +2967,8 @@ private void AddDeclaredNontypeMembers(DeclaredMembersAndInitializersBuilder bui
                         noteRecordParameters(recordStructDecl, parameterList, builder, diagnostics);
                         AddNonTypeMembers(builder, recordStructDecl.Members, diagnostics);
 
-                        // PROTOTYPE(record-structs): we will allow declaring parameterless constructors
+                        // We will allow declaring parameterless constructors
+                        // Tracking issue https://github.com/dotnet/roslyn/issues/52240
                         if (parameterList?.ParameterCount == 0)
                         {
                             diagnostics.Add(ErrorCode.ERR_StructsCantContainDefaultConstructor, parameterList.Location);

src/Compilers/CSharp/Portable/Symbols/TypeSymbol.cs

@@ -2253,7 +2253,6 @@ ITypeSymbol ITypeSymbolInternal.GetITypeSymbol()
             return GetITypeSymbol(DefaultNullableAnnotation);
         }
 
-        // PROTOTYPE(record-structs): rename to IsRecordClass?
         internal abstract bool IsRecord { get; }
 
         internal abstract bool IsRecordStruct { get; }

src/Compilers/CSharp/Portable/Syntax/SyntaxKindFacts.cs

@@ -795,7 +795,6 @@ public static SyntaxKind GetTypeDeclarationKind(SyntaxKind kind)
                 case SyntaxKind.InterfaceKeyword:
                     return SyntaxKind.InterfaceDeclaration;
                 case SyntaxKind.RecordKeyword:
-                    // PROTOTYPE(record-structs): anything we can do? 
                     return SyntaxKind.RecordDeclaration;
                 default:
                     return SyntaxKind.None;

src/Compilers/CSharp/Portable/Syntax/TypeDeclarationSyntax.cs

@@ -63,7 +63,6 @@ private static SyntaxKind GetTypeDeclarationKeywordKind(SyntaxKind kind)
                     return SyntaxKind.InterfaceKeyword;
                 case SyntaxKind.RecordDeclaration:
                     return SyntaxKind.RecordKeyword;
-                // PROTOTYPE(record-structs): update for record structs
                 default:
                     throw ExceptionUtilities.UnexpectedValue(kind);
             }