Record copy ctor must invoke base copy ctor (#45022)

src/Compilers/CSharp/Portable/Binder/Binder_Expressions.cs

@@ -3853,6 +3853,7 @@ private static bool IsNegativeConstantForArraySize(BoundExpression expression)
             {
                 TypeSymbol constructorReturnType = constructor.ReturnType;
                 Debug.Assert(constructorReturnType.IsVoidType()); //true of all constructors
+                NamedTypeSymbol baseType = containingType.BaseTypeNoUseSiteDiagnostics;
 
                 // Get the bound arguments and the argument names.
                 // : this(__arglist()) is legal
@@ -3949,19 +3950,23 @@ private static bool IsNegativeConstantForArraySize(BoundExpression expression)
 
                 MemberResolutionResult<MethodSymbol> memberResolutionResult;
                 ImmutableArray<MethodSymbol> candidateConstructors;
-                if (TryPerformConstructorOverloadResolution(
-                    initializerType,
-                    analyzedArguments,
-                    WellKnownMemberNames.InstanceConstructorName,
-                    errorLocation,
-                    false, // Don't suppress result diagnostics
-                    diagnostics,
-                    out memberResolutionResult,
-                    out candidateConstructors,
-                    allowProtectedConstructorsOfBaseType: true))
+                bool found = TryPerformConstructorOverloadResolution(
+                                    initializerType,
+                                    analyzedArguments,
+                                    WellKnownMemberNames.InstanceConstructorName,
+                                    errorLocation,
+                                    false, // Don't suppress result diagnostics
+                                    diagnostics,
+                                    out memberResolutionResult,
+                                    out candidateConstructors,
+                                    allowProtectedConstructorsOfBaseType: true);
+                MethodSymbol resultMember = memberResolutionResult.Member;
+
+                validateRecordCopyConstructor(constructor, baseType, resultMember, errorLocation, diagnostics);
+
+                if (found)
                 {
                     bool hasErrors = false;
-                    MethodSymbol resultMember = memberResolutionResult.Member;
 
                     if (resultMember == constructor)
                     {
@@ -3990,7 +3995,6 @@ private static bool IsNegativeConstantForArraySize(BoundExpression expression)
                     var arguments = analyzedArguments.Arguments.ToImmutable();
                     var refKinds = analyzedArguments.RefKinds.ToImmutableOrNull();
                     var argsToParamsOpt = memberResolutionResult.Result.ArgsToParamsOpt;
-
                     if (!hasErrors)
                     {
                         hasErrors = !CheckInvocationArgMixing(
@@ -4041,6 +4045,36 @@ private static bool IsNegativeConstantForArraySize(BoundExpression expression)
             {
                 analyzedArguments.Free();
             }
+
+            static void validateRecordCopyConstructor(MethodSymbol constructor, NamedTypeSymbol baseType, MethodSymbol resultMember, Location errorLocation, DiagnosticBag diagnostics)
+            {
+                if (IsUserDefinedRecordCopyConstructor(constructor))
+                {
+                    if (baseType.SpecialType == SpecialType.System_Object)
+                    {
+                        if (resultMember is null || resultMember.ContainingType.SpecialType != SpecialType.System_Object)
+                        {
+                            // Record deriving from object must use `base()`, not `this()`
+                            diagnostics.Add(ErrorCode.ERR_CopyConstructorMustInvokeBaseCopyConstructor, errorLocation);
+                        }
+
+                        return;
+                    }
+
+                    // Unless the base type is 'object', the constructor should invoke a base type copy constructor
+                    if (resultMember is null || !SynthesizedRecordCopyCtor.HasCopyConstructorSignature(resultMember))
+                    {
+                        diagnostics.Add(ErrorCode.ERR_CopyConstructorMustInvokeBaseCopyConstructor, errorLocation);
+                    }
+                }
+            }
+        }
+
+        internal static bool IsUserDefinedRecordCopyConstructor(MethodSymbol constructor)
+        {
+            return constructor.ContainingType is SourceNamedTypeSymbol sourceType &&
+                sourceType.IsRecord &&
+                SynthesizedRecordCopyCtor.HasCopyConstructorSignature(constructor);
         }
 
         private BoundExpression BindImplicitObjectCreationExpression(ImplicitObjectCreationExpressionSyntax node, DiagnosticBag diagnostics)

src/Compilers/CSharp/Portable/Binder/Binder_Statements.cs

@@ -3355,8 +3355,10 @@ private BoundNode BindConstructorBody(ConstructorDeclarationSyntax constructor,
             Debug.Assert(bodyBinder != null);
 
             if (constructor.Initializer?.IsKind(SyntaxKind.ThisConstructorInitializer) != true &&
-                ContainingType.GetMembersUnordered().OfType<SynthesizedRecordConstructor>().Any())
+                ContainingType.GetMembersUnordered().OfType<SynthesizedRecordConstructor>().Any() &&
+                !SynthesizedRecordCopyCtor.IsCopyConstructor(this.ContainingMember()))
             {
+                // Note: we check the constructor initializer of copy constructors elsewhere
                 Error(diagnostics, ErrorCode.ERR_UnexpectedOrMissingConstructorInitializerInRecord, constructor.Initializer?.ThisOrBaseKeyword ?? constructor.Identifier);
             }
 

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -6253,4 +6253,10 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_BadRecordMemberForPositionalParameter" xml:space="preserve">
     <value>Record member '{0}' must be a readable instance property of type '{1}' to match positional parameter '{2}'.</value>
   </data>
+  <data name="ERR_NoCopyConstructorInBaseType" xml:space="preserve">
+    <value>No accessible copy constructor found in base type '{0}'.</value>
+  </data>
+  <data name="ERR_CopyConstructorMustInvokeBaseCopyConstructor" xml:space="preserve">
+    <value>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</value>
+  </data>
 </root>

src/Compilers/CSharp/Portable/Compiler/MethodCompiler.cs

@@ -977,7 +977,8 @@ public override object VisitField(FieldSymbol symbol, TypeCompilationState argum
                     // Do not emit initializers if we are invoking another constructor of this class.
                     includeInitializersInBody = !processedInitializers.BoundInitializers.IsDefaultOrEmpty &&
                                                 !HasThisConstructorInitializer(methodSymbol) &&
-                                                !(methodSymbol is SynthesizedRecordCopyCtor); // A record copy constructor is special, regular initializers are not supposed to be executed by it.
+                                                !(methodSymbol is SynthesizedRecordCopyCtor) &&
+                                                !Binder.IsUserDefinedRecordCopyConstructor(methodSymbol); // A record copy constructor is special, regular initializers are not supposed to be executed by it.
 
                     body = BindMethodBody(methodSymbol, compilationState, diagsForCurrentMethod, out importChain, out originalBodyNested, out forSemanticModel);
                     if (diagsForCurrentMethod.HasAnyErrors() && body != null)
@@ -1846,6 +1847,11 @@ private static void ReportCtorInitializerCycles(MethodSymbol method, BoundExpres
                 }
             }
 
+            if (constructor is SynthesizedRecordCopyCtor copyCtor)
+            {
+                return GenerateBaseCopyConstructorInitializer(copyCtor, diagnostics);
+            }
+
             // Now, in order to do overload resolution, we're going to need a binder. There are
             // two possible situations:
             //
@@ -1978,6 +1984,53 @@ internal static BoundCall GenerateBaseParameterlessConstructorInitializer(Method
             { WasCompilerGenerated = true };
         }
 
+        private static BoundCall GenerateBaseCopyConstructorInitializer(SynthesizedRecordCopyCtor constructor, DiagnosticBag diagnostics)
+        {
+            NamedTypeSymbol containingType = constructor.ContainingType;
+            NamedTypeSymbol baseType = containingType.BaseTypeNoUseSiteDiagnostics;
+            Location diagnosticsLocation = constructor.Locations.FirstOrNone();
+
+            HashSet<DiagnosticInfo> useSiteDiagnostics = null;
+            MethodSymbol baseConstructor = SynthesizedRecordCopyCtor.FindCopyConstructor(baseType, containingType, ref useSiteDiagnostics);
+
+            if (baseConstructor is null)
+            {
+                diagnostics.Add(ErrorCode.ERR_NoCopyConstructorInBaseType, diagnosticsLocation, baseType);
+                return null;
+            }
+
+            if (Binder.ReportUseSiteDiagnostics(baseConstructor, diagnostics, diagnosticsLocation))
+            {
+                return null;
+            }
+
+            if (!useSiteDiagnostics.IsNullOrEmpty())
+            {
+                diagnostics.Add(diagnosticsLocation, useSiteDiagnostics);
+            }
+
+            CSharpSyntaxNode syntax = constructor.GetNonNullSyntaxNode();
+            BoundExpression receiver = new BoundThisReference(syntax, constructor.ContainingType) { WasCompilerGenerated = true };
+            BoundExpression argument = new BoundParameter(syntax, constructor.Parameters[0]);
+
+            return new BoundCall(
+                syntax: syntax,
+                receiverOpt: receiver,
+                method: baseConstructor,
+                arguments: ImmutableArray.Create(argument),
+                argumentNamesOpt: default,
+                argumentRefKindsOpt: default,
+                isDelegateCall: false,
+                expanded: false,
+                invokedAsExtensionMethod: false,
+                argsToParamsOpt: default,
+                resultKind: LookupResultKind.Viable,
+                binderOpt: null,
+                type: baseConstructor.ReturnType,
+                hasErrors: false)
+            { WasCompilerGenerated = true };
+        }
+
         /// <summary>
         /// Returns true if the method is a constructor and has a this() constructor initializer.
         /// </summary>

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

@@ -1832,6 +1832,8 @@ internal enum ErrorCode
         ERR_BadRecordBase = 8864,
         ERR_BadInheritanceFromRecord = 8865,
         ERR_BadRecordMemberForPositionalParameter = 8866,
+        ERR_NoCopyConstructorInBaseType = 8867,
+        ERR_CopyConstructorMustInvokeBaseCopyConstructor = 8868,
 
         #endregion
 

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

@@ -27,7 +27,7 @@ internal sealed class SourceConstructorSymbol : SourceConstructorSymbolBase
              ConstructorDeclarationSyntax syntax,
              MethodKind methodKind,
              DiagnosticBag diagnostics) :
-             base(containingType, location, syntax, methodKind, diagnostics)
+             base(containingType, location, syntax)
         {
             bool hasBlockBody = syntax.Body != null;
             _isExpressionBodied = !hasBlockBody && syntax.ExpressionBody != null;

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

@@ -19,9 +19,7 @@ internal abstract class SourceConstructorSymbolBase : SourceMemberMethodSymbol
         protected SourceConstructorSymbolBase(
             SourceMemberContainerTypeSymbol containingType,
             Location location,
-            CSharpSyntaxNode syntax,
-            MethodKind methodKind,
-            DiagnosticBag diagnostics)
+            CSharpSyntaxNode syntax)
             : base(containingType, syntax.GetReference(), ImmutableArray.Create(location), SyntaxFacts.HasYieldOperations(syntax))
         {
             Debug.Assert(

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

@@ -764,6 +764,14 @@ public override bool IsImplicitClass
             }
         }
 
+        internal bool IsRecord
+        {
+            get
+            {
+                return this.declaration.Declarations[0].Kind == DeclarationKind.Record;
+            }
+        }
+
         public override bool IsImplicitlyDeclared
         {
             get

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

@@ -18,7 +18,7 @@ internal sealed class SynthesizedRecordConstructor : SourceConstructorSymbolBase
              SourceMemberContainerTypeSymbol containingType,
              RecordDeclarationSyntax syntax,
              DiagnosticBag diagnostics) :
-             base(containingType, syntax.ParameterList!.GetLocation(), syntax, MethodKind.Constructor, diagnostics)
+             base(containingType, syntax.ParameterList!.GetLocation(), syntax)
         {
             this.MakeFlags(MethodKind.Constructor, containingType.IsAbstract ? DeclarationModifiers.Protected : DeclarationModifiers.Public, returnsVoid: true, isExtensionMethod: false);
         }

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

@@ -4,6 +4,8 @@
 
 #nullable enable
 
+using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis.PooledObjects;
 
@@ -30,13 +32,15 @@ internal sealed class SynthesizedRecordCopyCtor : SynthesizedInstanceConstructor
 
         public override ImmutableArray<ParameterSymbol> Parameters { get; }
 
+        public override Accessibility DeclaredAccessibility => Accessibility.Protected;
+
         internal override LexicalSortKey GetLexicalSortKey() => LexicalSortKey.GetSynthesizedMemberKey(_memberOffset);
 
         internal override void GenerateMethodBodyStatements(SyntheticBoundNodeFactory F, ArrayBuilder<BoundStatement> statements, DiagnosticBag diagnostics)
         {
             // Tracking issue for copy constructor in inheritance scenario: https://github.com/dotnet/roslyn/issues/44902
             // Write assignments to fields
-            //
+            // .ctor(DerivedRecordType original) : base((BaseRecordType)original)
             // {
             //     this.field1 = parameter.field1
             //     ...
@@ -51,5 +55,42 @@ internal override void GenerateMethodBodyStatements(SyntheticBoundNodeFactory F,
                 }
             }
         }
+
+        internal static MethodSymbol? FindCopyConstructor(NamedTypeSymbol containingType, NamedTypeSymbol within, ref HashSet<DiagnosticInfo> useSiteDiagnostics)
+        {
+            // We should handle ambiguities once we consider custom modifiers, as we do in overload resolution
+            // https://github.com/dotnet/roslyn/issues/45077
+            foreach (var member in containingType.InstanceConstructors)
+            {
+                if (HasCopyConstructorSignature(member) &&
+                    !member.HasUnsupportedMetadata &&
+                    AccessCheck.IsSymbolAccessible(member, within, ref useSiteDiagnostics))
+                {
+                    return member;
+                }
+            }
+
+            return null;
+        }
+
+        internal static bool IsCopyConstructor(Symbol member)
+        {
+            if (member is MethodSymbol { MethodKind: MethodKind.Constructor } method)
+            {
+                return HasCopyConstructorSignature(method);
+            }
+
+            return false;
+        }
+
+        internal static bool HasCopyConstructorSignature(MethodSymbol member)
+        {
+            NamedTypeSymbol containingType = member.ContainingType;
+            // We should relax the comparison to AllIgnoreOptions, so that a copy constructor with a custom modifier is recognized
+            // https://github.com/dotnet/roslyn/issues/45077
+            return member is MethodSymbol { IsStatic: false, ParameterCount: 1, Arity: 0 } method &&
+                method.Parameters[0].Type.Equals(containingType, TypeCompareKind.CLRSignatureCompareOptions) &&
+                method.Parameters[0].RefKind == RefKind.None;
+        }
     }
 }

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

@@ -197,6 +197,11 @@
         <target state="translated">Výraz typu {0} nelze zpracovat vzorem typu {1}. Použijte prosím verzi jazyka {2} nebo vyšší, aby odpovídala otevřenému typu se vzorem konstanty.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">Název {0} neodpovídá příslušnému parametru Deconstruct {1}.</target>
@@ -492,6 +497,11 @@
         <target state="translated">{0}: Typ použitý v příkazu using musí být implicitně převoditelný na System.IDisposable. Neměli jste v úmyslu použít await using místo using?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">Ein Ausdruck vom Typ "{0}" kann nicht von einem Muster vom Typ "{1}" behandelt werden. Verwenden Sie Sprachversion {2} oder höher, um einen offenen Typ mit einem konstanten Muster abzugleichen.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">Der Name "{0}" stimmt nicht mit dem entsprechenden Deconstruct-Parameter "{1}" überein.</target>
@@ -492,6 +497,11 @@
         <target state="translated">"{0}": Der in einer using-Anweisung verwendete Typ muss implizit in "System.IDisposable" konvertierbar sein. Meinten Sie "await using" anstelle von "using"?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">Un patrón de tipo "{0}" no se puede controlar por un patrón de tipo "{1}". Use la versión de lenguaje "{2}" o superior para buscar un tipo abierto con un patrón constante.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">El nombre "{0}" no coincide con el parámetro de "Deconstruct" correspondiente, "{1}".</target>
@@ -492,6 +497,11 @@
         <target state="translated">"{0}": el tipo usado en una instrucción using debe poder convertirse implícitamente en "System.IDisposable". ¿Quiso decir "await using" en lugar de "using"?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">Une expression de type '{0}' ne peut pas être prise en charge par un modèle de type '{1}'. Utilisez la version de langage '{2}' ou une version ultérieure pour faire correspondre un type ouvert à un modèle de constante.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">Le nom '{0}' ne correspond pas au paramètre 'Deconstruct' correspondant '{1}'.</target>
@@ -492,6 +497,11 @@
         <target state="translated">'{0}' : le type utilisé dans une instruction using doit être implicitement convertible en 'System.IDisposable'. Est-ce qu'il ne s'agit pas plutôt de 'await using' au lieu de 'using' ?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">Un'espressione di tipo '{0}' non può essere gestita da un criterio di tipo '{1}'. Usare la versione '{2}' o versioni successive del linguaggio per abbinare un tipo aperto a un criterio costante.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">Il nome '{0}' non corrisponde al parametro '{1}' di 'Deconstruct' corrispondente.</target>
@@ -492,6 +497,11 @@
         <target state="translated">'{0}': il tipo usato in un'istruzione using deve essere convertibile in modo implicito in 'System.IDisposable'. Si intendeva 'await using' invece di 'using'?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">型 '{0}' の式を型 '{1}' のパターンで処理することはできません。オープン型と定数パターンを一致させるには、言語バージョン '{2}' 以上をご使用ください。</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">名前 '{0}' は対応する 'Deconstruct' パラメーター '{1}' と一致しません。</target>
@@ -492,6 +497,11 @@
         <target state="translated">'{0}': using ステートメントで使用される型は、暗黙的に 'System.IDisposable' への変換が可能でなければなりません。'using' ではなく 'await using' ですか?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">'{0}' 형식의 식은 '{1}' 형식의 패턴으로 처리할 수 없습니다. 언어 버전 '{2}' 이상을 사용하여 개방형 형식과 상수 패턴을 일치시키세요.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">'{0}' 이름이 해당 'Deconstruct' 매개 변수 '{1}'과(와) 일치하지 않습니다.</target>
@@ -492,6 +497,11 @@
         <target state="translated">'{0}': using 문에 사용된 형식은 암시적으로 'System.IDisposable'로 변환할 수 있어야 합니다. 'using' 대신 'await using'을 사용하시겠습니까?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">Wyrażenie typu „{0}” nie może być obsługiwane przez wzorzec typu „{1}”. Użyj wersji języka „{2}” lub nowszej, aby dopasować typ otwarty za pomocą wzorca stałej.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">Nazwa „{0}” nie jest zgodna z odpowiednim parametrem „Deconstruct” „{1}”.</target>
@@ -492,6 +497,11 @@
         <target state="translated">„{0}”: typ użyty w instrukcji using musi umożliwiać niejawną konwersję na interfejs „System.IDisposable”. Czy chodziło Ci o instrukcję „await using”, a nie „using”?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">Uma expressão do tipo '{0}' não pode ser manipulada por um padrão do tipo '{1}'. Use a versão de linguagem '{2}' ou superior para corresponder a um tipo aberto com um padrão constante.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">O nome '{0}' não corresponde ao parâmetro 'Deconstruct' '{1}'.</target>
@@ -492,6 +497,11 @@
         <target state="translated">'{0}': o tipo usado em uma instrução using deve ser implicitamente conversível em 'System.IDisposable'. Você quis dizer 'await using' em vez de 'using'?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">Выражение типа "{0}" не может быть обработано шаблоном типа "{1}". Используйте версию языка "{2}" или более позднюю, чтобы сопоставить открытый тип с постоянным шаблоном.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">Имя "{0}" не соответствует указанному параметру "Deconstruct" "{1}".</target>
@@ -492,6 +497,11 @@
         <target state="translated">"{0}": тип, использованный в операторе using, должен иметь возможность неявного преобразования в System.IDisposable. Вы хотели использовать "await using" вместо "using"?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">'{0}' türünde bir ifade, '{1}' türünde bir desen tarafından işlenemez. Lütfen açık bir türü sabit bir desenle eşleştirmek için '{2}' veya daha yüksek bir dil sürümü kullanın.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">'{0}' adı ilgili '{1}' 'Deconstruct' parametresiyle eşleşmiyor.</target>
@@ -492,6 +497,11 @@
         <target state="translated">'{0}': using deyiminde kullanılan tür örtük olarak 'System.IDisposable' arabirimine dönüştürülebilir olmalıdır. 'using' yerine 'await using' mi kullanmak istediniz?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">"{0}" 类型的表达式不能由 "{1}" 类型的模式进行处理。请使用语言版本 "{2}" 或更高版本，将开放类型与常数模式进行匹配。</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">名称“{0}”与相应 "Deconstruct" 参数“{1}”不匹配。</target>
@@ -492,6 +497,11 @@
         <target state="translated">“{0}”: using 语句中使用的类型必须可隐式转换为 "System.IDisposable"。是否希望使用 "await using" 而非 "using"?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -197,6 +197,11 @@
         <target state="translated">類型 '{0}' 的運算式無法由類型 '{1}' 的模式處理。請使用語言 '{2}' 版或更新版本，以比對開放式類型與常數模式。</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_CopyConstructorMustInvokeBaseCopyConstructor">
+        <source>A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</source>
+        <target state="new">A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_DeconstructParameterNameMismatch">
         <source>The name '{0}' does not match the corresponding 'Deconstruct' parameter '{1}'.</source>
         <target state="translated">名稱 '{0}' 與對應的 'Deconstruct' 參數 '{1}' 不相符。</target>
@@ -492,6 +497,11 @@
         <target state="translated">'{0}': using 陳述式中使用的類型必須可以隱含轉換為 'System.IDisposable'。您指的是 'await using' 而不是 'using' 嗎?</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_NoCopyConstructorInBaseType">
+        <source>No accessible copy constructor found in base type '{0}'.</source>
+        <target state="new">No accessible copy constructor found in base type '{0}'.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_NoOutputDirectory">
         <source>Output directory could not be determined</source>
         <target state="new">Output directory could not be determined</target>

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

@@ -694,7 +694,11 @@ public void RecordClone2_0()
             var comp = CreateCompilation(@"
 record C(int x, int y)
 {
-    public C(C other) : this(other.x, other.y) { }
+    public C(C other)
+    {
+        x = other.x;
+        y = other.y;
+    }
 }");
             comp.VerifyDiagnostics();
 
@@ -720,19 +724,38 @@ .maxstack  1
 ");
             verifier.VerifyIL("C..ctor(C)", @"
 {
-  // Code size       19 (0x13)
-  .maxstack  3
+  // Code size       31 (0x1f)
+  .maxstack  2
   IL_0000:  ldarg.0
-  IL_0001:  ldarg.1
-  IL_0002:  callvirt   ""int C.x.get""
+  IL_0001:  call       ""object..ctor()""
+  IL_0006:  ldarg.0
   IL_0007:  ldarg.1
-  IL_0008:  callvirt   ""int C.y.get""
-  IL_000d:  call       ""C..ctor(int, int)""
-  IL_0012:  ret
+  IL_0008:  callvirt   ""int C.x.get""
+  IL_000d:  call       ""void C.x.init""
+  IL_0012:  ldarg.0
+  IL_0013:  ldarg.1
+  IL_0014:  callvirt   ""int C.y.get""
+  IL_0019:  call       ""void C.y.init""
+  IL_001e:  ret
 }
 ");
         }
 
+        [Fact]
+        public void RecordClone2_0_WithThisInitializer()
+        {
+            var comp = CreateCompilation(@"
+record C(int x, int y)
+{
+    public C(C other) : this(other.x, other.y) { }
+}");
+            comp.VerifyDiagnostics(
+                // (4,25): error CS8868: A copy constructor in a record must call a copy constructor of the base, or a parameterless object constructor if the record inherits from object.
+                //     public C(C other) : this(other.x, other.y) { }
+                Diagnostic(ErrorCode.ERR_CopyConstructorMustInvokeBaseCopyConstructor, "this").WithLocation(4, 25)
+                );
+        }
+
         [Fact]
         [WorkItem(44781, "https://github.com/dotnet/roslyn/issues/44781")]
         public void RecordClone2_1()
@@ -742,11 +765,7 @@ record C(int x, int y)
 {
     public C(C other) { }
 }");
-            comp.VerifyDiagnostics(
-                // (4,12): error CS8862: A constructor declared in a record with parameters must have 'this' constructor initializer.
-                //     public C(C other) { }
-                Diagnostic(ErrorCode.ERR_UnexpectedOrMissingConstructorInitializerInRecord, "C").WithLocation(4, 12)
-                );
+            comp.VerifyDiagnostics();
         }
 
         [Fact]
@@ -758,11 +777,7 @@ record C(int x, int y)
 {
     public C(C other) : base() { }
 }");
-            comp.VerifyDiagnostics(
-                // (4,25): error CS8862: A constructor declared in a record with parameters must have 'this' constructor initializer.
-                //     public C(C other) : base() { }
-                Diagnostic(ErrorCode.ERR_UnexpectedOrMissingConstructorInitializerInRecord, "base").WithLocation(4, 25)
-                );
+            comp.VerifyDiagnostics();
         }
 
         [Fact]
@@ -1196,6 +1211,9 @@ enum G : C { }";
 
             var comp = CreateCompilation(src);
             comp.VerifyDiagnostics(
+                // (3,8): error CS8867: No accessible copy constructor found in base type 'A'.
+                // record B : A { }
+                Diagnostic(ErrorCode.ERR_NoCopyConstructorInBaseType, "B").WithArguments("A").WithLocation(3, 8),
                 // (3,12): error CS8864: Records may only inherit from object or another record
                 // record B : A { }
                 Diagnostic(ErrorCode.ERR_BadRecordBase, "A").WithLocation(3, 12),
@@ -1209,7 +1227,7 @@ enum G : C { }";
                 // struct F : C { }
                 Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, "C").WithArguments("C").WithLocation(7, 12),
                 // (8,10): error CS1008: Type byte, sbyte, short, ushort, int, uint, long, or ulong expected
-                // enum G : C
+                // enum G : C { }
                 Diagnostic(ErrorCode.ERR_IntegralTypeExpected, "C").WithLocation(8, 10)
             );
         }
@@ -1240,17 +1258,20 @@ enum H : C { }
             });
 
             comp2.VerifyDiagnostics(
+                // (3,8): error CS8867: No accessible copy constructor found in base type 'A'.
+                // record E : A { }
+                Diagnostic(ErrorCode.ERR_NoCopyConstructorInBaseType, "E").WithArguments("A").WithLocation(3, 8),
                 // (3,12): error CS8864: Records may only inherit from object or another record
                 // record E : A { }
                 Diagnostic(ErrorCode.ERR_BadRecordBase, "A").WithLocation(3, 12),
                 // (4,15): error CS0527: Type 'C' in interface list is not an interface
-                // interface E : C { }
+                // interface F : C { }
                 Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, "C").WithArguments("C").WithLocation(4, 15),
                 // (5,12): error CS0527: Type 'C' in interface list is not an interface
-                // struct F : C { }
+                // struct G : C { }
                 Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, "C").WithArguments("C").WithLocation(5, 12),
                 // (6,10): error CS1008: Type byte, sbyte, short, ushort, int, uint, long, or ulong expected
-                // enum G : C
+                // enum H : C { }
                 Diagnostic(ErrorCode.ERR_IntegralTypeExpected, "C").WithLocation(6, 10)
             );
         }