Change name of record Clone method to unspeakable (#44852)

The compiler now uses a reserved name for the clone method which only
records will generate. Some existing tests are interesting if we ever
allow user-generation of the clone method but cannot be run in the
current state. I've left them in, but marked them skipped.

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

@@ -38,7 +38,6 @@ private BoundExpression BindWithExpression(WithExpressionSyntax syntax, Diagnost
             MethodSymbol? cloneMethod = null;
             if (!receiverType.IsErrorType())
             {
-                // PROTOTYPE: The receiver type must have a instance method called 'Clone' with no parameters
                 LookupMembersInType(
                     lookupResult,
                     receiverType,
@@ -64,39 +63,22 @@ private BoundExpression BindWithExpression(WithExpressionSyntax syntax, Diagnost
                 }
 
                 lookupResult.Clear();
-                // PROTOTYPE: discarding use-site diagnostics
-                useSiteDiagnostics = null;
 
-                if (cloneMethod is null)
+                if (cloneMethod is null ||
+                    !receiverType.IsEqualToOrDerivedFrom(
+                        cloneMethod.ReturnType,
+                        TypeCompareKind.ConsiderEverything,
+                        ref useSiteDiagnostics))
                 {
+                    useSiteDiagnostics = null;
                     hasErrors = true;
                     diagnostics.Add(ErrorCode.ERR_NoSingleCloneMethod, syntax.Receiver.Location, receiverType);
                 }
-                else
-                {
-                    // Check return type
-                    if (!receiverType.IsEqualToOrDerivedFrom(
-                            cloneMethod.ReturnType,
-                            TypeCompareKind.ConsiderEverything,
-                            ref useSiteDiagnostics))
-                    {
-                        hasErrors = true;
-                        diagnostics.Add(
-                            ErrorCode.ERR_ContainingTypeMustDeriveFromWithReturnType,
-                            syntax.Receiver.Location,
-                            receiverType,
-                            cloneMethod.ReturnType);
-                    }
-
-                    // PROTOTYPE: discarding use-site diagnostics
-                    useSiteDiagnostics = null;
-                }
             }
 
-            var cloneReturnType = cloneMethod?.ReturnType;
             var initializer = BindInitializerExpression(
                 syntax.Initializer,
-                cloneReturnType ?? receiverType,
+                receiverType,
                 syntax.Receiver,
                 diagnostics);
 
@@ -108,7 +90,7 @@ private BoundExpression BindWithExpression(WithExpressionSyntax syntax, Diagnost
                 receiver,
                 cloneMethod,
                 initializer,
-                cloneReturnType ?? receiverType,
+                receiverType,
                 hasErrors: hasErrors);
         }
     }

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -6128,13 +6128,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
     <value>The receiver of a `with` expression must have a non-void type.</value>
   </data>
   <data name="ERR_NoSingleCloneMethod" xml:space="preserve">
-    <value>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</value>
-  </data>
-  <data name="ERR_ContainingTypeMustDeriveFromWithReturnType" xml:space="preserve">
-    <value>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</value>
-  </data>
-  <data name="ERR_WithMemberIsNotRecordProperty" xml:space="preserve">
-    <value>All arguments to a `with` expression must be compiler-generated record properties.</value>
+    <value>The receiver type '{0}' is not a valid record type.</value>
   </data>
   <data name="ERR_AssignmentInitOnly" xml:space="preserve">
     <value>Init-only property or indexer '{0}' can only be assigned in an object initializer, or on 'this' or 'base' in an instance constructor or an 'init' accessor.</value>
@@ -6247,4 +6241,10 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_MultipleRecordParameterLists" xml:space="preserve">
     <value>Only a single record partial declaration may have a parameter list</value>
   </data>
+  <data name="ERR_BadRecordBase" xml:space="preserve">
+    <value>Records may only inherit from object or another record</value>
+  </data>
+  <data name="ERR_BadInheritanceFromRecord" xml:space="preserve">
+    <value>Only records may inherit from records.</value>
+  </data>
 </root>

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

@@ -1827,11 +1827,11 @@ internal enum ErrorCode
         ERR_BadInitAccessor = 8856,
         ERR_InvalidWithReceiverType = 8857,
         ERR_NoSingleCloneMethod = 8858,
-        ERR_ContainingTypeMustDeriveFromWithReturnType = 8859,
-        ERR_WithMemberIsNotRecordProperty = 8860,
         ERR_UnexpectedArgumentList = 8861,
         ERR_UnexpectedOrMissingConstructorInitializerInRecord = 8862,
         ERR_MultipleRecordParameterLists = 8863,
+        ERR_BadRecordBase = 8864,
+        ERR_BadInheritanceFromRecord = 8865,
 
         #endregion
 

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_ObjectCreationExpression.cs

@@ -108,6 +108,7 @@ public override BoundNode VisitWithExpression(BoundWithExpression withExpr)
         {
             RoslynDebug.AssertNotNull(withExpr.CloneMethod);
             Debug.Assert(withExpr.CloneMethod.ParameterCount == 0);
+            Debug.Assert(withExpr.Receiver.Type!.Equals(withExpr.Type, TypeCompareKind.ConsiderEverything));
 
             // for a with expression of the form
             //
@@ -116,14 +117,16 @@ public override BoundNode VisitWithExpression(BoundWithExpression withExpr)
             // we want to lower it to a call to the receiver's `Clone` method, then
             // set the given record properties. i.e.
             //
-            //      var tmp = receiver.Clone();
+            //      var tmp = (ReceiverType)receiver.Clone();
             //      tmp.P1 = e1;
             //      tmp.P2 = e2;
             //      tmp
 
-            var cloneCall = _factory.Call(
-                VisitExpression(withExpr.Receiver),
-                withExpr.CloneMethod);
+            var cloneCall = _factory.Convert(
+                withExpr.Type,
+                _factory.Call(
+                    VisitExpression(withExpr.Receiver),
+                    withExpr.CloneMethod));
 
             return MakeExpressionWithInitializer(
                 withExpr.Syntax,

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

@@ -111,6 +111,21 @@ protected override void CheckBase(DiagnosticBag diagnostics)
 
                 localBase.CheckAllConstraints(DeclaringCompilation, conversions, location, diagnostics);
             }
+
+            // Records can only inherit from other records or object
+            if (declaration.Kind == DeclarationKind.Record &&
+                localBase.SpecialType != SpecialType.System_Object &&
+                SynthesizedRecordClone.FindValidCloneMethod(localBase) is null)
+            {
+                var baseLocation = FindBaseRefSyntax(localBase);
+                diagnostics.Add(ErrorCode.ERR_BadRecordBase, baseLocation);
+            }
+            else if (declaration.Kind != DeclarationKind.Record &&
+                     SynthesizedRecordClone.FindValidCloneMethod(localBase) is object)
+            {
+                var baseLocation = FindBaseRefSyntax(localBase);
+                diagnostics.Add(ErrorCode.ERR_BadInheritanceFromRecord, baseLocation);
+            }
         }
 
         protected override void CheckInterfaces(DiagnosticBag diagnostics)

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

@@ -17,11 +17,25 @@ namespace Microsoft.CodeAnalysis.CSharp.Symbols
 {
     internal sealed class SynthesizedRecordClone : SynthesizedInstanceMethodSymbol
     {
+        public override TypeWithAnnotations ReturnTypeWithAnnotations { get; }
         public override NamedTypeSymbol ContainingType { get; }
+        public override bool IsOverride { get; }
 
         public SynthesizedRecordClone(NamedTypeSymbol containingType)
         {
             ContainingType = containingType;
+            var baseType = containingType.BaseTypeNoUseSiteDiagnostics;
+            if (FindValidCloneMethod(baseType) is { } baseClone)
+            {
+                // Use covariant returns when available
+                ReturnTypeWithAnnotations = baseClone.ReturnTypeWithAnnotations;
+                IsOverride = true;
+            }
+            else
+            {
+                ReturnTypeWithAnnotations = TypeWithAnnotations.Create(isNullableEnabled: true, containingType);
+                IsOverride = false;
+            }
         }
 
         public override string Name => WellKnownMemberNames.CloneMethodName;
@@ -44,10 +58,6 @@ public SynthesizedRecordClone(NamedTypeSymbol containingType)
 
         public override ImmutableArray<ParameterSymbol> Parameters => ImmutableArray<ParameterSymbol>.Empty;
 
-        public override TypeWithAnnotations ReturnTypeWithAnnotations => TypeWithAnnotations.Create(
-            isNullableEnabled: true,
-            ContainingType);
-
         public override FlowAnalysisAnnotations ReturnTypeFlowAnalysisAnnotations => FlowAnalysisAnnotations.None;
 
         public override ImmutableHashSet<string> ReturnNotNullIfParameterNotNull => ImmutableHashSet<string>.Empty;
@@ -71,10 +81,7 @@ public override ImmutableArray<TypeWithAnnotations> TypeArgumentsWithAnnotations
 
         public override bool IsStatic => false;
 
-        // PROTOTYPE: Inheritance is not handled
-        public override bool IsVirtual => true;
-
-        public override bool IsOverride => false;
+        public override bool IsVirtual => !IsOverride;
 
         public override bool IsAbstract => false;
 
@@ -104,9 +111,9 @@ internal override ImmutableArray<string> GetAppliedConditionalSymbols()
         internal override IEnumerable<SecurityAttribute> GetSecurityInformation()
             => Array.Empty<SecurityAttribute>();
 
-        internal override bool IsMetadataNewSlot(bool ignoreInterfaceImplementationChanges = false) => false;
+        internal override bool IsMetadataNewSlot(bool ignoreInterfaceImplementationChanges = false) => !IsOverride;
 
-        internal override bool IsMetadataVirtual(bool ignoreInterfaceImplementationChanges = false) => false;
+        internal override bool IsMetadataVirtual(bool ignoreInterfaceImplementationChanges = false) => true;
 
         internal override bool SynthesizesLoweredBoundBody => true;
 
@@ -114,7 +121,6 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
         {
             var F = new SyntheticBoundNodeFactory(this, ContainingType.GetNonNullSyntaxNode(), compilationState, diagnostics);
 
-            // PROTOTYPE: what about base fields?
             var members = ContainingType.GetMembers(WellKnownMemberNames.InstanceConstructorName);
             foreach (var member in members)
             {
@@ -129,5 +135,27 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
 
             throw ExceptionUtilities.Unreachable;
         }
+
+        internal static MethodSymbol? FindValidCloneMethod(NamedTypeSymbol containingType)
+        {
+            for (; !(containingType is null); containingType = containingType.BaseTypeNoUseSiteDiagnostics)
+            {
+                foreach (var member in containingType.GetMembers(WellKnownMemberNames.CloneMethodName))
+                {
+                    if (member is MethodSymbol
+                    {
+                        DeclaredAccessibility: Accessibility.Public,
+                        IsStatic: false,
+                        IsAbstract: false,
+                        ParameterCount: 0,
+                        Arity: 0
+                    } method && (method.IsOverride || method.IsVirtual))
+                    {
+                        return method;
+                    }
+                }
+            }
+            return null;
+        }
     }
 }

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

@@ -45,7 +45,10 @@ internal override void GenerateMethodBodyStatements(SyntheticBoundNodeFactory F,
             var param = F.Parameter(Parameters[0]);
             foreach (var field in ContainingType.GetFieldsToEmit())
             {
-                statements.Add(F.Assignment(F.Field(F.This(), field), F.Field(param, field)));
+                if (!field.IsStatic)
+                {
+                    statements.Add(F.Assignment(F.Field(F.This(), field), F.Field(param, field)));
+                }
             }
         }
     }

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Neplatný operand pro porovnávací vzorek. Vyžaduje se hodnota, ale nalezeno: {0}.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Výčty, třídy a struktury není možné deklarovat v rozhraní, které má parametr typu in/out.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Ungültiger Operand für die Musterübereinstimmung. Ein Wert ist erforderlich, gefunden wurde aber "{0}".</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Enumerationen, Klassen und Strukturen können nicht in Schnittstellen mit Parametern vom Typ "in" oder "out" deklariert werden.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Operando no válido para la coincidencia de patrones. Se requería un valor, pero se encontró '{0}'.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Las enumeraciones, las clases y las estructuras no se pueden declarar en una interfaz que tenga un parámetro de tipo "in" o "out".</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Opérande non valide pour les critères spéciaux ; la valeur nécessaire n'est pas celle trouvée, '{0}'.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Les enums, les classes et les structures ne peuvent pas être déclarés dans une interface contenant un paramètre de type 'in' ou 'out'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">L'operando non è valido per i criteri di ricerca. È richiesto un valore ma è stato trovato '{0}'.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Non è possibile dichiarare enumerazioni, classi e strutture in un'interfaccia che contiene un parametro di tipo 'in' o 'out'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">パターン マッチには使用できないオペランドです。値が必要ですが、'{0}' が見つかりました。</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">'in' または 'out' の型パラメーターを持つインターフェイス内では、列挙体、クラス、および構造体を宣言することはできません。</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">패턴 일치에 대한 피연산자가 잘못되었습니다. 값이 필요하지만 '{0}'을(를) 찾았습니다.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">'in' 또는 'out' 형식 매개 변수가 있는 인터페이스에서 열거형, 클래스, 구조체를 선언할 수 없습니다.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Nieprawidłowy operand dla dopasowania wzorca; wymagana jest wartość, a znaleziono „{0}”.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Wyliczenia, klasy i struktury nie mogą być deklarowane w interfejsie mającym parametr typu „in” lub „out”.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Operando inválido para correspondência de padrão. Um valor era obrigatório, mas '{0}' foi encontrado.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Não é possível declarar enumerações, classes e estruturas em uma interface que tenha um parâmetro de tipo 'in' ou 'out'.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Недопустимый операнд для сопоставления с шаблоном. Требуется значение, но найдено "{0}".</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Перечисления, классы и структуры не могут быть объявлены в интерфейсе, имеющем параметр типа "In" или "Out".</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">Desen eşleşmesi için işlenen geçersiz. Değer gerekiyordu ancak '{0}' bulundu.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">Sabit listeleri, sınıflar ve yapılar 'in' veya 'out' tür parametresine sahip bir arabirimde bildirilemez.</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">用于模式匹配的操作数无效；需要值，但找到的是“{0}”。</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">无法在含有 "in" 或 "out" 类型参数的接口中声明枚举、类和结构。</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -102,6 +102,11 @@
         <target state="new">'{0}' cannot be used as a modifier on a function pointer parameter.</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadInheritanceFromRecord">
+        <source>Only records may inherit from records.</source>
+        <target state="new">Only records may inherit from records.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadInitAccessor">
         <source>The 'init' accessor is not valid on static members</source>
         <target state="new">The 'init' accessor is not valid on static members</target>
@@ -127,6 +132,11 @@
         <target state="translated">模式比對運算元無效; 需要值，但找到 '{0}'。</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_BadRecordBase">
+        <source>Records may only inherit from object or another record</source>
+        <target state="new">Records may only inherit from object or another record</target>
+        <note />
+      </trans-unit>
       <trans-unit id="ERR_BadRecordDeclaration">
         <source>A positional record must have both a 'data' modifier and non-empty parameter list</source>
         <target state="new">A positional record must have both a 'data' modifier and non-empty parameter list</target>
@@ -182,11 +192,6 @@
         <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_ContainingTypeMustDeriveFromWithReturnType">
-        <source>The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</source>
-        <target state="new">The type of the 'with' expression receiver, '{0}', does not derive from the return type of the 'Clone' method, '{1}'.</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>
@@ -483,8 +488,8 @@
         <note />
       </trans-unit>
       <trans-unit id="ERR_NoSingleCloneMethod">
-        <source>The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</source>
-        <target state="new">The receiver type '{0}' does not have an accessible parameterless instance method named "Clone".</target>
+        <source>The receiver type '{0}' is not a valid record type.</source>
+        <target state="new">The receiver type '{0}' is not a valid record type.</target>
         <note />
       </trans-unit>
       <trans-unit id="ERR_NotNullConstraintMustBeFirst">
@@ -762,11 +767,6 @@
         <target state="translated">無法在有 'in' 或 'out' 型別參數的介面中宣告列舉、類別和結構。</target>
         <note />
       </trans-unit>
-      <trans-unit id="ERR_WithMemberIsNotRecordProperty">
-        <source>All arguments to a `with` expression must be compiler-generated record properties.</source>
-        <target state="new">All arguments to a `with` expression must be compiler-generated record properties.</target>
-        <note />
-      </trans-unit>
       <trans-unit id="ERR_WrongFuncPtrCallingConvention">
         <source>Calling convention of '{0}' is not compatible with '{1}'.</source>
         <target state="new">Calling convention of '{0}' is not compatible with '{1}'.</target>

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

@@ -2173,7 +2173,7 @@ public record C(int i)
 
             var cMembers = comp.GlobalNamespace.GetMember<NamedTypeSymbol>("C").GetMembers();
             AssertEx.SetEqual(new[] {
-                "C C.Clone()",
+                "C C.<>Clone()",
                 "System.Type C.EqualityContract.get",
                 "System.Type C.EqualityContract { get; }",
                 "C..ctor(System.Int32 i)",

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

@@ -35,7 +35,6 @@ record C(int x, int y)
                     "Microsoft",
                     "C"),
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -69,7 +68,6 @@ public void PositionalRecord2()
                 Add( // C Type parameters
                     "T"),
                 Add( // Members
-                    "C<T> C<T>.Clone()",
                     "System.Int32 C<T>.x { get; init; }",
                     "T C<T>.t { get; init; }",
                     "System.Boolean C<T>.Equals(C<T>? )",
@@ -100,7 +98,6 @@ public void NominalRecord()
     T t { get; }
 `}";
             var members = new[] {
-                "C<T> C<T>.Clone()",
                 "System.Int32 C<T>.x { get; }",
                 "T C<T>.t { get; }",
                 "System.Boolean C<T>.Equals(C<T>? )",
@@ -1708,7 +1705,6 @@ record C(int X) : Base`(X`)
                     "Microsoft",
                     "C"),
                 Add( // Members + parameters
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1724,7 +1720,6 @@ record C(int X) : Base`(X`)
                     "void System.Object.Finalize()"),
                 s_pop,
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1758,7 +1753,6 @@ public void RecordBaseArguments_02()
                     "Microsoft",
                     "C"),
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1795,7 +1789,6 @@ public void RecordBaseArguments_03()
                     "Microsoft",
                     "C"),
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1811,7 +1804,6 @@ public void RecordBaseArguments_03()
                     "void System.Object.Finalize()"),
                 s_pop,
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1850,7 +1842,6 @@ public void RecordBaseArguments_04()
                     "Microsoft",
                     "C"),
                 Add( // Members + parameters
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1866,7 +1857,6 @@ public void RecordBaseArguments_04()
                     "void System.Object.Finalize()"),
                 s_pop,
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1882,7 +1872,6 @@ public void RecordBaseArguments_04()
                     "void System.Object.Finalize()"),
                 s_pop,
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1920,7 +1909,6 @@ public void RecordBaseArguments_05()
                     "Microsoft",
                     "C"),
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1936,7 +1924,6 @@ public void RecordBaseArguments_05()
                     "void System.Object.Finalize()"),
                 s_pop,
                 Add( // Members + parameters
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",
@@ -1952,7 +1939,6 @@ public void RecordBaseArguments_05()
                     "void System.Object.Finalize()"),
                 s_pop,
                 Add( // Members
-                    "C C.Clone()",
                     "System.Boolean C.Equals(C? )",
                     "System.Boolean C.Equals(System.Object? )",
                     "System.Boolean System.Object.Equals(System.Object obj)",

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

@@ -993,7 +993,7 @@ record C
 }");
             var members = comp.GlobalNamespace.GetTypeMember("C").GetMembers();
             AssertEx.Equal(new[] {
-                "C! C.Clone()",
+                "C! C.<>Clone()",
                 "System.Type! C.EqualityContract.get",
                 "System.Type! C.EqualityContract { get; }",
                 "System.Int32 C.<X>k__BackingField",
@@ -1181,5 +1181,139 @@ public void DataClassAndStruct()
                 Diagnostic(ErrorCode.ERR_LocalDuplicate, "Y").WithArguments("Y").WithLocation(5, 27)
             );
         }
+
+        [Fact]
+        public void RecordInheritance()
+        {
+            var src = @"
+class A { }
+record B : A { }
+record C : B { }
+class D : C { }
+interface E : C { }
+struct F : C { }
+enum G : C { }";
+
+            var comp = CreateCompilation(src);
+            comp.VerifyDiagnostics(
+                // (3,12): error CS8864: Records may only inherit from object or another record
+                // record B : A { }
+                Diagnostic(ErrorCode.ERR_BadRecordBase, "A").WithLocation(3, 12),
+                // (5,11): error CS8865: Only records may inherit from records.
+                // class D : C { }
+                Diagnostic(ErrorCode.ERR_BadInheritanceFromRecord, "C").WithLocation(5, 11),
+                // (6,15): error CS0527: Type 'C' in interface list is not an interface
+                // interface E : C { }
+                Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, "C").WithArguments("C").WithLocation(6, 15),
+                // (7,12): error CS0527: Type 'C' in interface list is not an interface
+                // 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
+                Diagnostic(ErrorCode.ERR_IntegralTypeExpected, "C").WithLocation(8, 10)
+            );
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void RecordInheritance2(bool emitReference)
+        {
+            var src = @"
+public class A { }
+public record B { }
+public record C : B { }";
+            var comp = CreateCompilation(src);
+
+            var src2 = @"
+record D : C { }
+record E : A { }
+interface F : C { }
+struct G : C { }
+enum H : C { }
+";
+
+            var comp2 = CreateCompilation(src2,
+                parseOptions: TestOptions.RegularPreview,
+                references: new[] {
+                emitReference ? comp.EmitToImageReference() : comp.ToMetadataReference()
+            });
+
+            comp2.VerifyDiagnostics(
+                // (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 { }
+                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 { }
+                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
+                Diagnostic(ErrorCode.ERR_IntegralTypeExpected, "C").WithLocation(6, 10)
+            );
+        }
+
+        [Fact]
+        public void GenericRecord()
+        {
+            var src = @"
+using System;
+record A<T>
+{
+    public T Prop { get; init; }
+}
+record B : A<int>;
+record C<T>(T Prop2) : A<T>;
+class P
+{
+    public static void Main()
+    {
+        var a = new A<int>() { Prop = 1 };
+        var a2 = a with { Prop = 2 };
+        Console.WriteLine(a.Prop + "" "" + a2.Prop);
+
+        var b = new B() { Prop = 3 };
+        var b2 = b with { Prop = 4 };
+        Console.WriteLine(b.Prop + "" "" + b2.Prop);
+
+        var c = new C<int>(5) { Prop = 6 };
+        var c2 = c with { Prop = 7, Prop2 = 8 };
+        Console.WriteLine(c.Prop + "" "" + c.Prop2);
+        Console.WriteLine(c2.Prop2 + "" "" + c2.Prop);
+    }
+}";
+            CompileAndVerify(src, expectedOutput: @"
+1 2
+3 4
+6 5
+8 7");
+        }
+
+        [Fact]
+        public void RecordCloneSymbol()
+        {
+            var src = @"
+record R;
+record R2 : R";
+            var comp = CreateCompilation(src);
+            var r = comp.GlobalNamespace.GetTypeMember("R");
+            var clone = (MethodSymbol)r.GetMembers(WellKnownMemberNames.CloneMethodName).Single();
+            Assert.False(clone.IsOverride);
+            Assert.True(clone.IsVirtual);
+            Assert.False(clone.IsAbstract);
+            Assert.Equal(0, clone.ParameterCount);
+            Assert.Equal(0, clone.Arity);
+
+            var r2 = comp.GlobalNamespace.GetTypeMember("R2");
+            var clone2 = (MethodSymbol)r2.GetMembers(WellKnownMemberNames.CloneMethodName).Single();
+            Assert.True(clone2.IsOverride);
+            Assert.False(clone2.IsVirtual);
+            Assert.False(clone2.IsAbstract);
+            Assert.Equal(0, clone2.ParameterCount);
+            Assert.Equal(0, clone2.Arity);
+            Assert.True(clone2.OverriddenMethod.Equals(clone, TypeCompareKind.ConsiderEverything));
+        }
     }
 }

src/Compilers/Core/Portable/Operations/ControlFlowGraphBuilder.cs

@@ -6991,7 +6991,7 @@ public override IOperation VisitWithExpression(IWithExpressionOperation operatio
             IOperation cloned = operation.CloneMethod is null
                 ? MakeInvalidOperation(visitedInstance.Type, visitedInstance)
                 : new InvocationOperation(operation.CloneMethod, visitedInstance,
-                    isVirtual: false, arguments: ImmutableArray<IArgumentOperation>.Empty,
+                    isVirtual: true, arguments: ImmutableArray<IArgumentOperation>.Empty,
                     semanticModel: null, operation.Syntax, operation.Type, operation.ConstantValue, isImplicit: true);
 
             return PopStackFrame(frame, HandleObjectOrCollectionInitializer(operation.Initializer, cloned));

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

@@ -343,7 +343,7 @@ public static class WellKnownMemberNames
         /// </summary>
         public const string SliceMethodName = "Slice";
 
-        // PROTOTYPE: internal since this has yet to be approved
-        internal const string CloneMethodName = "Clone";
+        // internal until we settle on this long-term
+        internal const string CloneMethodName = "<>Clone";
     }
 }