Add print methods to records (#46616)

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -6389,10 +6389,10 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_RuntimeDoesNotSupportCovariantPropertiesOfClasses" xml:space="preserve">
     <value>'{0}': Target runtime doesn't support covariant types in overrides. Type must be '{2}' to match overridden member '{1}'</value>
   </data>
-  <data name="ERR_SealedGetHashCodeInRecord" xml:space="preserve">
+  <data name="ERR_SealedAPIInRecord" xml:space="preserve">
     <value>'{0}' cannot be sealed because containing record is not sealed.</value>
   </data>
-  <data name="ERR_DoesNotOverrideBaseEquals" xml:space="preserve">
+  <data name="ERR_DoesNotOverrideBaseMethod" xml:space="preserve">
     <value>'{0}' does not override expected method from '{1}'.</value>
   </data>
   <data name="WRN_ConstOutOfRangeChecked" xml:space="preserve">

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

@@ -1853,7 +1853,7 @@ internal enum ErrorCode
         ERR_InvalidWithReceiverType = 8857,
         ERR_NoSingleCloneMethod = 8858,
         ERR_CloneDisallowedInRecord = 8859,
-        // Unused 8860
+        // available = 8860,
         ERR_UnexpectedArgumentList = 8861,
         ERR_UnexpectedOrMissingConstructorInitializerInRecord = 8862,
         ERR_MultipleRecordParameterLists = 8863,
@@ -1863,8 +1863,8 @@ internal enum ErrorCode
         ERR_NoCopyConstructorInBaseType = 8867,
         ERR_CopyConstructorMustInvokeBaseCopyConstructor = 8868,
         ERR_DoesNotOverrideMethodFromObject = 8869,
-        ERR_SealedGetHashCodeInRecord = 8870,
-        ERR_DoesNotOverrideBaseEquals = 8871,
+        ERR_SealedAPIInRecord = 8870,
+        ERR_DoesNotOverrideBaseMethod = 8871,
         ERR_NotOverridableAPIInRecord = 8872,
         ERR_NonPublicAPIInRecord = 8873,
         ERR_SignatureMismatchInRecord = 8874,

src/Compilers/CSharp/Portable/SymbolDisplay/SymbolDisplayVisitor.Types.cs

@@ -711,6 +711,11 @@ private void AddTypeKind(INamedTypeSymbol symbol)
         /// </summary>
         private static IMethodSymbol FindValidCloneMethod(ITypeSymbol containingType)
         {
+            if (containingType.SpecialType == SpecialType.System_Object)
+            {
+                return null;
+            }
+
             IMethodSymbol candidate = null;
 
             foreach (var member in containingType.GetMembers(WellKnownMemberNames.CloneMethodName))

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

@@ -3035,9 +3035,12 @@ private void AddSynthesizedRecordMembersIfNecessary(MembersAndInitializersBuilde
             var thisEquals = addThisEquals(equalityContract);
             addOtherEquals();
             addObjectEquals(thisEquals);
-            addHashCode(equalityContract);
+            addGetHashCode(equalityContract);
             addEqualityOperators();
 
+            var printMembers = addPrintMembersMethod();
+            addToStringMethod(printMembers);
+
             memberSignatures.Free();
 
             // We put synthesized record members first so that errors about conflicts show up on user-defined members rather than all
@@ -3140,6 +3143,94 @@ void addCloneMethod()
                 members.Add(new SynthesizedRecordClone(this, memberOffset: members.Count, diagnostics));
             }
 
+            MethodSymbol addPrintMembersMethod()
+            {
+                var targetMethod = new SignatureOnlyMethodSymbol(
+                    WellKnownMemberNames.PrintMembersMethodName,
+                    this,
+                    MethodKind.Ordinary,
+                    Cci.CallingConvention.HasThis,
+                    ImmutableArray<TypeParameterSymbol>.Empty,
+                    ImmutableArray.Create<ParameterSymbol>(new SignatureOnlyParameterSymbol(
+                        TypeWithAnnotations.Create(compilation.GetWellKnownType(WellKnownType.System_Text_StringBuilder)),
+                        ImmutableArray<CustomModifier>.Empty,
+                        isParams: false,
+                        RefKind.None)),
+                    RefKind.None,
+                    isInitOnly: false,
+                    returnType: TypeWithAnnotations.Create(compilation.GetSpecialType(SpecialType.System_Boolean)),
+                    refCustomModifiers: ImmutableArray<CustomModifier>.Empty,
+                    explicitInterfaceImplementations: ImmutableArray<MethodSymbol>.Empty);
+
+                MethodSymbol printMembersMethod;
+                if (!memberSignatures.TryGetValue(targetMethod, out Symbol? existingPrintMembersMethod))
+                {
+                    printMembersMethod = new SynthesizedRecordPrintMembers(this, memberOffset: members.Count, diagnostics);
+                    members.Add(printMembersMethod);
+                }
+                else
+                {
+                    printMembersMethod = (MethodSymbol)existingPrintMembersMethod;
+                    if (this.IsSealed && this.BaseTypeNoUseSiteDiagnostics.IsObjectType())
+                    {
+                        if (printMembersMethod.DeclaredAccessibility != Accessibility.Private)
+                        {
+                            diagnostics.Add(ErrorCode.ERR_NonPrivateAPIInRecord, printMembersMethod.Locations[0], printMembersMethod);
+                        }
+                    }
+                    else if (printMembersMethod.DeclaredAccessibility != Accessibility.Protected)
+                    {
+                        diagnostics.Add(ErrorCode.ERR_NonProtectedAPIInRecord, printMembersMethod.Locations[0], printMembersMethod);
+                    }
+
+                    if (!printMembersMethod.ReturnType.Equals(targetMethod.ReturnType, TypeCompareKind.AllIgnoreOptions))
+                    {
+                        if (!printMembersMethod.ReturnType.IsErrorType())
+                        {
+                            diagnostics.Add(ErrorCode.ERR_SignatureMismatchInRecord, printMembersMethod.Locations[0], printMembersMethod, targetMethod.ReturnType);
+                        }
+                    }
+                    else
+                    {
+                        SynthesizedRecordPrintMembers.VerifyOverridesPrintMembersFromBase(printMembersMethod, diagnostics);
+                    }
+
+                    reportStaticOrNotOverridableAPIInRecord(printMembersMethod, diagnostics);
+                }
+
+                return printMembersMethod;
+            }
+
+            void addToStringMethod(MethodSymbol printMethod)
+            {
+                var targetMethod = new SignatureOnlyMethodSymbol(
+                    WellKnownMemberNames.ObjectToString,
+                    this,
+                    MethodKind.Ordinary,
+                    Cci.CallingConvention.HasThis,
+                    ImmutableArray<TypeParameterSymbol>.Empty,
+                    ImmutableArray<ParameterSymbol>.Empty,
+                    RefKind.None,
+                    isInitOnly: false,
+                    returnType: TypeWithAnnotations.Create(compilation.GetSpecialType(SpecialType.System_String)),
+                    refCustomModifiers: ImmutableArray<CustomModifier>.Empty,
+                    explicitInterfaceImplementations: ImmutableArray<MethodSymbol>.Empty);
+
+                if (!memberSignatures.TryGetValue(targetMethod, out Symbol? existingToStringMethod))
+                {
+                    var toStringMethod = new SynthesizedRecordToString(this, printMethod, memberOffset: members.Count, diagnostics);
+                    members.Add(toStringMethod);
+                }
+                else
+                {
+                    var toStringMethod = (MethodSymbol)existingToStringMethod;
+                    if (!SynthesizedRecordObjectMethod.VerifyOverridesMethodFromObject(toStringMethod, SpecialType.System_String, diagnostics) && toStringMethod.IsSealed && !IsSealed)
+                    {
+                        diagnostics.Add(ErrorCode.ERR_SealedAPIInRecord, toStringMethod.Locations[0], toStringMethod);
+                    }
+                }
+            }
+
             ImmutableArray<PropertySymbol> addProperties(ImmutableArray<ParameterSymbol> recordParameters)
             {
                 var existingOrAddedMembers = ArrayBuilder<PropertySymbol>.GetInstance(recordParameters.Length);
@@ -3219,7 +3310,7 @@ void addObjectEquals(MethodSymbol thisEquals)
                 members.Add(new SynthesizedRecordObjEquals(this, thisEquals, memberOffset: members.Count, diagnostics));
             }
 
-            void addHashCode(PropertySymbol equalityContract)
+            void addGetHashCode(PropertySymbol equalityContract)
             {
                 var targetMethod = new SignatureOnlyMethodSymbol(
                     WellKnownMemberNames.ObjectGetHashCode,
@@ -3244,7 +3335,7 @@ void addHashCode(PropertySymbol equalityContract)
                     var method = (MethodSymbol)existingHashCodeMethod;
                     if (!SynthesizedRecordObjectMethod.VerifyOverridesMethodFromObject(method, SpecialType.System_Int32, diagnostics) && method.IsSealed && !IsSealed)
                     {
-                        diagnostics.Add(ErrorCode.ERR_SealedGetHashCodeInRecord, method.Locations[0], method);
+                        diagnostics.Add(ErrorCode.ERR_SealedAPIInRecord, method.Locations[0], method);
                     }
                 }
             }

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

@@ -125,7 +125,8 @@ protected override void CheckBase(DiagnosticBag diagnostics)
 
                 if (declaration.Kind == DeclarationKind.Record)
                 {
-                    if (SynthesizedRecordClone.FindValidCloneMethod(localBase, ref useSiteDiagnostics) is null)
+                    if (SynthesizedRecordClone.FindValidCloneMethod(localBase, ref useSiteDiagnostics) is null ||
+                        SynthesizedRecordPrintMembers.FindValidPrintMembersMethod(localBase, DeclaringCompilation) is null)
                     {
                         diagnostics.Add(ErrorCode.ERR_BadRecordBase, baseLocation);
                     }

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

@@ -54,7 +54,7 @@ protected override void MethodChecks(DiagnosticBag diagnostics)
             if (overridden is object &&
                 !overridden.ContainingType.Equals(ContainingType.BaseTypeNoUseSiteDiagnostics, TypeCompareKind.AllIgnoreOptions))
             {
-                diagnostics.Add(ErrorCode.ERR_DoesNotOverrideBaseEquals, Locations[0], this, ContainingType.BaseTypeNoUseSiteDiagnostics);
+                diagnostics.Add(ErrorCode.ERR_DoesNotOverrideBaseMethod, Locations[0], this, ContainingType.BaseTypeNoUseSiteDiagnostics);
             }
         }
 

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

@@ -4,12 +4,9 @@
 
 #nullable enable
 
-using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
-using System.Reflection;
-using Microsoft.Cci;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp.Symbols
@@ -150,6 +147,11 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
         // Note: this method was replicated in SymbolDisplayVisitor.FindValidCloneMethod
         internal static MethodSymbol? FindValidCloneMethod(TypeSymbol containingType, ref HashSet<DiagnosticInfo>? useSiteDiagnostics)
         {
+            if (containingType.IsObjectType())
+            {
+                return null;
+            }
+
             MethodSymbol? candidate = null;
 
             foreach (var member in containingType.GetMembers(WellKnownMemberNames.CloneMethodName))

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

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#nullable enable
+
+using System.Collections.Immutable;
+using System.Diagnostics;
+using System.Linq;
+using Microsoft.CodeAnalysis.PooledObjects;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.CSharp.Symbols
+{
+    /// <summary>
+    /// The `bool PrintMembers(StringBuilder)` method is responsible for printing members declared
+    /// in the containing type that are "printable" (public fields and properties),
+    /// and delegating to the base to print inherited printable members. Base members get printed first.
+    /// It returns true if the record contains some printable members.
+    /// The method is used to implement `ToString()`.
+    /// </summary>
+    internal sealed class SynthesizedRecordPrintMembers : SynthesizedRecordOrdinaryMethod
+    {
+        public SynthesizedRecordPrintMembers(
+            SourceMemberContainerTypeSymbol containingType,
+            int memberOffset,
+            DiagnosticBag diagnostics)
+            : base(containingType, WellKnownMemberNames.PrintMembersMethodName, hasBody: true, memberOffset, diagnostics)
+        {
+        }
+
+        protected override DeclarationModifiers MakeDeclarationModifiers(DeclarationModifiers allowedModifiers, DiagnosticBag diagnostics)
+        {
+            var result = (ContainingType.BaseTypeNoUseSiteDiagnostics.IsObjectType() && ContainingType.IsSealed) ?
+                DeclarationModifiers.Private :
+                DeclarationModifiers.Protected;
+
+            if (virtualPrintInBase() is object)
+            {
+                result |= DeclarationModifiers.Override;
+            }
+            else
+            {
+                result |= ContainingType.IsSealed ? DeclarationModifiers.None : DeclarationModifiers.Virtual;
+            }
+
+            Debug.Assert((result & ~allowedModifiers) == 0);
+#if DEBUG
+            Debug.Assert(modifiersAreValid(result));
+#endif
+            return result;
+
+            MethodSymbol? virtualPrintInBase()
+            {
+                NamedTypeSymbol baseType = ContainingType.BaseTypeNoUseSiteDiagnostics;
+
+                if (!baseType.IsObjectType())
+                {
+                    return FindValidPrintMembersMethod(baseType, ContainingType.DeclaringCompilation);
+                }
+
+                return null;
+            }
+
+#if DEBUG
+            static bool modifiersAreValid(DeclarationModifiers modifiers)
+            {
+                if ((modifiers & DeclarationModifiers.AccessibilityMask) != DeclarationModifiers.Private &&
+                    (modifiers & DeclarationModifiers.AccessibilityMask) != DeclarationModifiers.Protected)
+                {
+                    return false;
+                }
+
+                modifiers &= ~DeclarationModifiers.AccessibilityMask;
+
+                switch (modifiers)
+                {
+                    case DeclarationModifiers.None:
+                    case DeclarationModifiers.Override:
+                    case DeclarationModifiers.Virtual:
+                        return true;
+                    default:
+                        return false;
+                }
+            }
+#endif
+        }
+
+        protected override (TypeWithAnnotations ReturnType, ImmutableArray<ParameterSymbol> Parameters, bool IsVararg, ImmutableArray<TypeParameterConstraintClause> DeclaredConstraintsForOverrideOrImplementation) MakeParametersAndBindReturnType(DiagnosticBag diagnostics)
+        {
+            var compilation = DeclaringCompilation;
+            var location = ReturnTypeLocation;
+            return (ReturnType: TypeWithAnnotations.Create(Binder.GetSpecialType(compilation, SpecialType.System_Boolean, location, diagnostics)),
+                    Parameters: ImmutableArray.Create<ParameterSymbol>(
+                        new SourceSimpleParameterSymbol(owner: this,
+                            TypeWithAnnotations.Create(Binder.GetWellKnownType(compilation, WellKnownType.System_Text_StringBuilder, diagnostics, location), NullableAnnotation.NotAnnotated),
+                            ordinal: 0, RefKind.None, "builder", isDiscard: false, Locations)),
+                    IsVararg: false,
+                    DeclaredConstraintsForOverrideOrImplementation: ImmutableArray<TypeParameterConstraintClause>.Empty);
+        }
+
+        protected override int GetParameterCountFromSyntax() => 1;
+
+        internal override void GenerateMethodBody(TypeCompilationState compilationState, DiagnosticBag diagnostics)
+        {
+            var F = new SyntheticBoundNodeFactory(this, ContainingType.GetNonNullSyntaxNode(), compilationState, diagnostics);
+            try
+            {
+                ImmutableArray<Symbol> printableMembers = ContainingType.GetMembers()
+                    .WhereAsArray(m => m.DeclaredAccessibility == Accessibility.Public && (m.Kind is SymbolKind.Field or SymbolKind.Property));
+
+                if (ReturnType.IsErrorType() ||
+                    printableMembers.Any(m => m.GetTypeOrReturnType().Type.IsErrorType()))
+                {
+                    F.CloseMethod(F.ThrowNull());
+                    return;
+                }
+
+                ArrayBuilder<BoundStatement>? block = printableMembers.IsEmpty ? null : ArrayBuilder<BoundStatement>.GetInstance();
+                BoundParameter builder = F.Parameter(this.Parameters[0]);
+                if (ContainingType.BaseTypeNoUseSiteDiagnostics.IsObjectType())
+                {
+                    if (printableMembers.IsEmpty)
+                    {
+                        // return false;
+                        F.CloseMethod(F.Return(F.Literal(false)));
+                        return;
+                    }
+                }
+                else
+                {
+                    MethodSymbol? printMethod = FindValidPrintMembersMethod(ContainingType.BaseTypeNoUseSiteDiagnostics, DeclaringCompilation);
+                    if (printMethod is null)
+                    {
+                        F.CloseMethod(F.ThrowNull()); // an error was reported in base checks already
+                        return;
+                    }
+
+                    var basePrintCall = F.Call(receiver: F.Base(ContainingType.BaseTypeNoUseSiteDiagnostics), printMethod, builder);
+                    if (printableMembers.IsEmpty)
+                    {
+                        // return base.print(builder);
+                        F.CloseMethod(F.Return(basePrintCall));
+                        return;
+                    }
+                    else
+                    {
+                        // if (base.print(builder))
+                        //     builder.Append(", ")
+                        block!.Add(F.If(basePrintCall, makeAppendString(F, builder, ", ")));
+                    }
+                }
+
+                Debug.Assert(!printableMembers.IsEmpty && block is object);
+
+                for (var i = 0; i < printableMembers.Length; i++)
+                {
+                    // builder.Append(<name>);
+                    // builder.Append(" = ");
+                    // builder.Append((object)<value>);
+                    // builder.Append(", "); // except for last member
+
+                    var member = printableMembers[i];
+                    block.Add(makeAppendString(F, builder, member.Name));
+                    block.Add(makeAppendString(F, builder, " = "));
+
+                    var value = member.Kind switch
+                    {
+                        SymbolKind.Field => F.Field(F.This(), (FieldSymbol)member),
+                        SymbolKind.Property => F.Property(F.This(), (PropertySymbol)member),
+                        _ => throw ExceptionUtilities.UnexpectedValue(member.Kind)
+                    };
+
+                    block.Add(F.ExpressionStatement(
+                        F.Call(receiver: builder,
+                            F.WellKnownMethod(WellKnownMember.System_Text_StringBuilder__AppendObject),
+                            F.Convert(F.SpecialType(SpecialType.System_Object), value))));
+
+                    if (i < printableMembers.Length - 1)
+                    {
+                        block.Add(makeAppendString(F, builder, ", "));
+                    }
+                }
+
+                block.Add(F.Return(F.Literal(true)));
+
+                F.CloseMethod(F.Block(block.ToImmutableAndFree()));
+            }
+            catch (SyntheticBoundNodeFactory.MissingPredefinedMember ex)
+            {
+                diagnostics.Add(ex.Diagnostic);
+                F.CloseMethod(F.ThrowNull());
+            }
+
+            static BoundStatement makeAppendString(SyntheticBoundNodeFactory F, BoundParameter builder, string value)
+            {
+                return F.ExpressionStatement(F.Call(receiver: builder, F.WellKnownMethod(WellKnownMember.System_Text_StringBuilder__AppendString), F.StringLiteral(value)));
+            }
+        }
+
+        internal static MethodSymbol? FindValidPrintMembersMethod(TypeSymbol containingType, CSharpCompilation compilation)
+        {
+            if (containingType.IsObjectType())
+            {
+                return null;
+            }
+
+            MethodSymbol? candidate = null;
+            var stringBuilder = TypeWithAnnotations.Create(compilation.GetWellKnownType(WellKnownType.System_Text_StringBuilder));
+
+            foreach (var member in containingType.GetMembers(WellKnownMemberNames.PrintMembersMethodName))
+            {
+                if (member is MethodSymbol { DeclaredAccessibility: Accessibility.Protected, IsStatic: false, ParameterCount: 1, Arity: 0 } method &&
+                    method.ParameterTypesWithAnnotations[0].Equals(stringBuilder, TypeCompareKind.AllIgnoreOptions))
+                {
+                    if (candidate is object)
+                    {
+                        // An ambiguity case, can come from metadata, treat as an error for simplicity.
+                        return null;
+                    }
+
+                    candidate = method;
+                }
+            }
+
+            if (candidate is null ||
+                !(containingType.IsSealed || candidate.IsOverride || candidate.IsVirtual) ||
+                candidate.ReturnType.SpecialType != SpecialType.System_Boolean)
+            {
+                return null;
+            }
+
+            return candidate;
+        }
+
+        internal static void VerifyOverridesPrintMembersFromBase(MethodSymbol overriding, DiagnosticBag diagnostics)
+        {
+            NamedTypeSymbol baseType = overriding.ContainingType.BaseTypeNoUseSiteDiagnostics;
+            if (baseType.IsObjectType())
+            {
+                return;
+            }
+
+            bool reportAnError = false;
+
+            if (!overriding.IsOverride)
+            {
+                reportAnError = true;
+            }
+            else
+            {
+                var overridden = overriding.OverriddenMethod;
+
+                if (overridden is object &&
+                    !overridden.ContainingType.Equals(baseType, TypeCompareKind.AllIgnoreOptions))
+                {
+                    reportAnError = true;
+                }
+            }
+
+            if (reportAnError)
+            {
+                diagnostics.Add(ErrorCode.ERR_DoesNotOverrideBaseMethod, overriding.Locations[0], overriding, baseType);
+            }
+        }
+    }
+}

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

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#nullable enable
+
+using System.Collections.Immutable;
+using System.Diagnostics;
+using Microsoft.CodeAnalysis.PooledObjects;
+
+namespace Microsoft.CodeAnalysis.CSharp.Symbols
+{
+    /// <summary>
+    /// The record includes a synthesized override of object.ToString().
+    /// For `record R(int I) { public int J; }` it prints `R { I = ..., J = ... }`.
+    ///
+    /// The method can be declared explicitly. It is an error if the explicit
+    /// declaration does not match the expected signature or accessibility, or
+    /// if the explicit declaration doesn't allow overriding it in a derived type and
+    /// the record type is not sealed.
+    /// It is an error if either synthesized or explicitly declared method doesn't
+    /// override `object.ToString()` (for example, due to shadowing in intermediate base types, etc.).
+    /// </summary>
+    internal sealed class SynthesizedRecordToString : SynthesizedRecordObjectMethod
+    {
+        private readonly MethodSymbol _printMethod;
+        public SynthesizedRecordToString(SourceMemberContainerTypeSymbol containingType, MethodSymbol printMethod, int memberOffset, DiagnosticBag diagnostics)
+            : base(containingType, WellKnownMemberNames.ObjectToString, memberOffset, diagnostics)
+        {
+            Debug.Assert(printMethod is object);
+            _printMethod = printMethod;
+        }
+
+        protected override (TypeWithAnnotations ReturnType, ImmutableArray<ParameterSymbol> Parameters, bool IsVararg, ImmutableArray<TypeParameterConstraintClause> DeclaredConstraintsForOverrideOrImplementation) MakeParametersAndBindReturnType(DiagnosticBag diagnostics)
+        {
+            var compilation = DeclaringCompilation;
+            var location = ReturnTypeLocation;
+            return (ReturnType: TypeWithAnnotations.Create(Binder.GetSpecialType(compilation, SpecialType.System_String, location, diagnostics)),
+                    Parameters: ImmutableArray<ParameterSymbol>.Empty,
+                    IsVararg: false,
+                    DeclaredConstraintsForOverrideOrImplementation: ImmutableArray<TypeParameterConstraintClause>.Empty);
+        }
+
+        protected override int GetParameterCountFromSyntax() => 0;
+
+        internal override void GenerateMethodBody(TypeCompilationState compilationState, DiagnosticBag diagnostics)
+        {
+            var F = new SyntheticBoundNodeFactory(this, this.SyntaxNode, compilationState, diagnostics);
+
+            try
+            {
+                CSharpCompilation compilation = ContainingType.DeclaringCompilation;
+                var stringBuilder = F.WellKnownType(WellKnownType.System_Text_StringBuilder);
+                var stringBuilderCtor = F.WellKnownMethod(WellKnownMember.System_Text_StringBuilder__ctor);
+
+                var builderLocalSymbol = F.SynthesizedLocal(stringBuilder);
+                BoundLocal builderLocal = F.Local(builderLocalSymbol);
+                var block = ArrayBuilder<BoundStatement>.GetInstance();
+                // var builder = new StringBuilder();
+                block.Add(F.Assignment(builderLocal, F.New(stringBuilderCtor)));
+
+                // builder.Append(<name>);
+                block.Add(makeAppendString(F, builderLocal, ContainingType.Name));
+
+                // builder.Append(" { ");
+                block.Add(makeAppendString(F, builderLocal, " { "));
+
+                // this.print(builder);
+                block.Add(F.ExpressionStatement(F.Call(F.This(), _printMethod, builderLocal)));
+
+                // builder.Append(" } ");
+                block.Add(makeAppendString(F, builderLocal, " } "));
+
+                // return builder.ToString();
+                block.Add(F.Return(F.Call(builderLocal, F.SpecialMethod(SpecialMember.System_Object__ToString))));
+
+                F.CloseMethod(F.Block(ImmutableArray.Create(builderLocalSymbol), block.ToImmutableAndFree()));
+            }
+            catch (SyntheticBoundNodeFactory.MissingPredefinedMember ex)
+            {
+                diagnostics.Add(ex.Diagnostic);
+                F.CloseMethod(F.ThrowNull());
+            }
+
+            static BoundStatement makeAppendString(SyntheticBoundNodeFactory F, BoundLocal builder, string value)
+            {
+                return F.ExpressionStatement(F.Call(receiver: builder, F.WellKnownMethod(WellKnownMember.System_Text_StringBuilder__AppendString), F.StringLiteral(value)));
+            }
+        }
+    }
+}

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ Pokud chcete odstranit toto varování, můžete místo toho použít /reference
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ Um die Warnung zu beheben, können Sie stattdessen /reference verwenden (Einbett
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ Para eliminar la advertencia puede usar /reference (establezca la propiedad Embe
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ Pour supprimer l'avertissement, vous pouvez utiliser la commande /reference (dé
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ Per rimuovere l'avviso, è invece possibile usare /reference (impostare la propr
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ Aby usunąć ostrzeżenie, możesz zamiast tego użyć opcji /reference (ustaw w
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.pt-BR.xlf

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10616,4 +10616,4 @@ Para incorporar informações de tipo de interoperabilidade para os dois assembl
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

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

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ Uyarıyı kaldırmak için, /reference kullanabilirsiniz (Birlikte Çalışma T
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hans.xlf

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hant.xlf

@@ -267,7 +267,7 @@
         <target state="new">'{0}' does not override expected property from '{1}'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_DoesNotOverrideBaseEquals">
+      <trans-unit id="ERR_DoesNotOverrideBaseMethod">
         <source>'{0}' does not override expected method from '{1}'.</source>
         <target state="new">'{0}' does not override expected method from '{1}'.</target>
         <note />
@@ -757,7 +757,7 @@
         <target state="new">The target runtime doesn't support extensible or runtime-environment default calling conventions.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_SealedGetHashCodeInRecord">
+      <trans-unit id="ERR_SealedAPIInRecord">
         <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 />
@@ -10618,4 +10618,4 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
       </trans-unit>
     </body>
   </file>
-</xliff>
+</xliff>
\ No newline at end of file

src/Compilers/CSharp/Test/Semantic/Semantics/InitOnlyMemberTests.cs

@@ -2182,6 +2182,8 @@ public record C(int i)
                 "void modreq(System.Runtime.CompilerServices.IsExternalInit) C.i.init",
                 "System.Int32 C.i { get; init; }",
                 "void C.M()",
+                "System.String C.ToString()",
+                "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                 "System.Boolean C.op_Inequality(C? r1, C? r2)",
                 "System.Boolean C.op_Equality(C? r1, C? r2)",
                 "System.Int32 C.GetHashCode()",

src/Compilers/CSharp/Test/Semantic/Semantics/LookupPositionTests.cs

@@ -37,6 +37,7 @@ record C(int x, int y)
                 Add( // Members
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -45,6 +46,7 @@ record C(int x, int y)
                     "System.Int32 C.y { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -73,6 +75,7 @@ public void PositionalRecord2()
                     "T C<T>.t { get; init; }",
                     "System.Boolean C<T>.Equals(C<T>? other)",
                     "System.Boolean C<T>.Equals(System.Object? obj)",
+                    "System.Boolean C<T>." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -81,6 +84,7 @@ public void PositionalRecord2()
                     "System.Object System.Object.MemberwiseClone()",
                     "void C<T>.Deconstruct(out System.Int32 x, out T t)",
                     "void System.Object.Finalize()",
+                    "System.String C<T>.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C<T>.EqualityContract { get; }",
                     "System.Type System.Object.GetType()"),
@@ -104,15 +108,17 @@ public void NominalRecord()
                 "T C<T>.t { get; }",
                 "System.Boolean C<T>.Equals(C<T>? other)",
                 "System.Boolean C<T>.Equals(System.Object? obj)",
+                "System.Boolean C<T>." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                 "System.Boolean System.Object.Equals(System.Object obj)",
                 "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                 "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
                 "System.Int32 C<T>.GetHashCode()",
                 "System.Int32 System.Object.GetHashCode()",
                 "System.Object System.Object.MemberwiseClone()",
+                "System.String C<T>.ToString()",
                 "void System.Object.Finalize()",
                 "System.String System.Object.ToString()",
-                    "System.Type C<T>.EqualityContract { get; }",
+                "System.Type C<T>.EqualityContract { get; }",
                 "System.Type System.Object.GetType()",
             };
             var expectedNames = MakeExpectedSymbols(
@@ -1710,6 +1716,7 @@ record C(int X) : Base`(X`)
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1717,6 +1724,7 @@ record C(int X) : Base`(X`)
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Int32 X",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1727,6 +1735,7 @@ record C(int X) : Base`(X`)
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1734,6 +1743,7 @@ record C(int X) : Base`(X`)
                     "System.Int32 C.X { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1762,12 +1772,14 @@ public void RecordBaseArguments_02()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
                     "System.Int32 C.GetHashCode()",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1799,6 +1811,7 @@ public void RecordBaseArguments_03()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1806,6 +1819,7 @@ public void RecordBaseArguments_03()
                     "System.Int32 C.X { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1816,6 +1830,7 @@ public void RecordBaseArguments_03()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1823,6 +1838,7 @@ public void RecordBaseArguments_03()
                     "System.Int32 C.X { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1856,6 +1872,7 @@ public void RecordBaseArguments_04()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1863,6 +1880,7 @@ public void RecordBaseArguments_04()
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Int32 X",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1873,6 +1891,7 @@ public void RecordBaseArguments_04()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1880,6 +1899,7 @@ public void RecordBaseArguments_04()
                     "System.Int32 C.X { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1890,6 +1910,7 @@ public void RecordBaseArguments_04()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1897,6 +1918,7 @@ public void RecordBaseArguments_04()
                     "System.Int32 C.X { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1929,6 +1951,7 @@ public void RecordBaseArguments_05()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1936,6 +1959,7 @@ public void RecordBaseArguments_05()
                     "System.Int32 C.X { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1946,6 +1970,7 @@ public void RecordBaseArguments_05()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1953,6 +1978,7 @@ public void RecordBaseArguments_05()
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Int32 X",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -1963,6 +1989,7 @@ public void RecordBaseArguments_05()
                     "System.Boolean C.Equals(Base? other)",
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -1970,6 +1997,7 @@ public void RecordBaseArguments_05()
                     "System.Int32 C.X { get; init; }",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -2083,6 +2111,7 @@ record C(int X)
                 Add( // Members
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -2091,6 +2120,7 @@ record C(int X)
                     "System.Int32 C.Z",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -2124,6 +2154,7 @@ record C(int X)
                 Add( // Members
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -2132,6 +2163,7 @@ record C(int X)
                     "System.Int32 C.Z",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",
@@ -2160,6 +2192,7 @@ record C(int X)
                 Add( // Members
                     "System.Boolean C.Equals(C? other)",
                     "System.Boolean C.Equals(System.Object? obj)",
+                    "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder builder)",
                     "System.Boolean System.Object.Equals(System.Object obj)",
                     "System.Boolean System.Object.Equals(System.Object objA, System.Object objB)",
                     "System.Boolean System.Object.ReferenceEquals(System.Object objA, System.Object objB)",
@@ -2168,6 +2201,7 @@ record C(int X)
                     "System.Int32 C.Z",
                     "System.Int32 System.Object.GetHashCode()",
                     "System.Object System.Object.MemberwiseClone()",
+                    "System.String C.ToString()",
                     "System.String System.Object.ToString()",
                     "System.Type C.EqualityContract { get; }",
                     "System.Type System.Object.GetType()",

src/Compilers/CSharp/Test/Symbol/Symbols/Source/RecordTests.cs

@@ -1076,6 +1076,8 @@ record C
                 "System.String! C.Y { get; init; }",
                 "System.String! C.Y.get",
                 "void C.Y.init",
+                "System.String C.ToString()",
+                "System.Boolean C." + WellKnownMemberNames.PrintMembersMethodName + "(System.Text.StringBuilder! builder)",
                 "System.Boolean C.operator !=(C? r1, C? r2)",
                 "System.Boolean C.operator ==(C? r1, C? r2)",
                 "System.Int32 C.GetHashCode()",

src/Compilers/Core/Portable/Symbols/WellKnownMemberNames.cs

@@ -345,6 +345,7 @@ public static class WellKnownMemberNames
 
         // internal until we settle on this long-term
         internal const string CloneMethodName = "<Clone>$";
+        internal const string PrintMembersMethodName = "PrintMembers";
 
         /// <summary>
         /// The name of an entry point method synthesized for top-level statements.

src/Compilers/Core/Portable/WellKnownMember.cs

@@ -511,6 +511,10 @@ internal enum WellKnownMember
 
         System_Runtime_CompilerServices_PreserveBaseOverridesAttribute__ctor,
 
+        System_Text_StringBuilder__AppendString,
+        System_Text_StringBuilder__AppendObject,
+        System_Text_StringBuilder__ctor,
+
         Count
 
         // Remember to update the AllWellKnownTypeMembers tests when making changes here

src/Compilers/Core/Portable/WellKnownMembers.cs

@@ -3490,6 +3490,29 @@ static WellKnownMembers()
                 0,                                                                                                          // Arity
                     0,                                                                                                      // Method Signature
                     (byte)SignatureTypeCode.TypeHandle, (byte)SpecialType.System_Void, // Return Type
+
+                // System_Text_StringBuilder__AppendString
+                (byte)MemberFlags.Method,                                                                                   // Flags
+                (byte)WellKnownType.ExtSentinel, (byte)(WellKnownType.System_Text_StringBuilder - WellKnownType.ExtSentinel),    // DeclaringTypeId
+                0,                                                                                                          // Arity
+                    1,                                                                                                      // Method Signature
+                    (byte)SignatureTypeCode.TypeHandle, (byte)WellKnownType.ExtSentinel, (byte)(WellKnownType.System_Text_StringBuilder - WellKnownType.ExtSentinel), // Return Type
+                    (byte)SignatureTypeCode.TypeHandle, (byte)SpecialType.System_String,
+
+                // System_Text_StringBuilder__AppendObject
+                (byte)MemberFlags.Method,                                                                                   // Flags
+                (byte)WellKnownType.ExtSentinel, (byte)(WellKnownType.System_Text_StringBuilder - WellKnownType.ExtSentinel),    // DeclaringTypeId
+                0,                                                                                                          // Arity
+                    1,                                                                                                      // Method Signature
+                    (byte)SignatureTypeCode.TypeHandle, (byte)WellKnownType.ExtSentinel, (byte)(WellKnownType.System_Text_StringBuilder - WellKnownType.ExtSentinel), // Return Type
+                    (byte)SignatureTypeCode.TypeHandle, (byte)SpecialType.System_Object,
+
+                // System_Text_StringBuilder__ctor
+                (byte)MemberFlags.Constructor,                                                                              // Flags
+                (byte)WellKnownType.ExtSentinel, (byte)(WellKnownType.System_Text_StringBuilder - WellKnownType.ExtSentinel),    // DeclaringTypeId
+                0,                                                                                                          // Arity
+                    0,                                                                                                      // Method Signature
+                    (byte)SignatureTypeCode.TypeHandle, (byte)SpecialType.System_Void, // Return Type
             };
 
             string[] allNames = new string[(int)WellKnownMember.Count]
@@ -3928,6 +3951,9 @@ static WellKnownMembers()
                 ".ctor",                                    // System_Runtime_CompilerServices_NativeIntegerAttribute__ctor
                 ".ctor",                                    // System_Runtime_CompilerServices_NativeIntegerAttribute__ctorTransformFlags
                 ".ctor",                                    // System_Runtime_CompilerServices_PreserveBaseOverridesAttribute__ctor
+                "Append",                                   // System_Text_StringBuilder__AppendString
+                "Append",                                   // System_Text_StringBuilder__AppendObject
+                ".ctor",                                    // System_Text_StringBuilder__ctor
             };
 
             s_descriptors = MemberDescriptor.InitializeFromStream(new System.IO.MemoryStream(initializationBytes, writable: false), allNames);

src/Compilers/Core/Portable/WellKnownTypes.cs

@@ -6,7 +6,6 @@
 
 using System.Collections.Generic;
 using System.Diagnostics;
-using Microsoft.CodeAnalysis.Text;
 
 namespace Microsoft.CodeAnalysis
 {
@@ -315,6 +314,8 @@ internal enum WellKnownType
         System_Runtime_InteropServices_OutAttribute,
         System_Runtime_CompilerServices_PreserveBaseOverridesAttribute,
 
+        System_Text_StringBuilder,
+
         NextAvailable,
 
         // Remember to update the AllWellKnownTypes tests when making changes here
@@ -621,6 +622,8 @@ internal static class WellKnownTypes
             "System.Runtime.CompilerServices.IsExternalInit",
             "System.Runtime.InteropServices.OutAttribute",
             "System.Runtime.CompilerServices.PreserveBaseOverridesAttribute",
+
+            "System.Text.StringBuilder",
         };
 
         private readonly static Dictionary<string, WellKnownType> s_nameToTypeIdMap = new Dictionary<string, WellKnownType>((int)Count);