CSharpTestBase.CreateCompilation(new[] { source, IsExternalInitTypeDefinition },\n parseOptions: TestOptions.RegularPreview);\n\n private CompilationVerifier CompileAndVerify(\n CSharpTestSource src,\n string? expectedOutput = null,\n IEnumerable
? references = null)\n => base.CompileAndVerify(\n new[] { src, IsExternalInitTypeDefinition },\n expectedOutput: expectedOutput,\n parseOptions: TestOptions.RegularPreview,\n references: references,\n // init-only is unverifiable\n verify: Verification.Skipped);\n\n [Fact]\n public void StructRecord1()\n {\n var src = @\"\nrecord struct Point(int X, int Y);\";\n\n var verifier = CompileAndVerify(src).VerifyDiagnostics();\n verifier.VerifyIL(\"Point.Equals(object)\", @\"\n{\n // Code size 23 (0x17)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: isinst \"\"Point\"\"\n IL_0006: brfalse.s IL_0015\n IL_0008: ldarg.0\n IL_0009: ldarg.1\n IL_000a: unbox.any \"\"Point\"\"\n IL_000f: call \"\"readonly bool Point.Equals(Point)\"\"\n IL_0014: ret\n IL_0015: ldc.i4.0\n IL_0016: ret\n}\");\n verifier.VerifyIL(\"Point.Equals(Point)\", @\"\n{\n // Code size 49 (0x31)\n .maxstack 3\n IL_0000: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_0005: ldarg.0\n IL_0006: ldfld \"\"int Point.k__BackingField\"\"\n IL_000b: ldarg.1\n IL_000c: ldfld \"\"int Point.k__BackingField\"\"\n IL_0011: callvirt \"\"bool System.Collections.Generic.EqualityComparer.Equals(int, int)\"\"\n IL_0016: brfalse.s IL_002f\n IL_0018: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_001d: ldarg.0\n IL_001e: ldfld \"\"int Point.k__BackingField\"\"\n IL_0023: ldarg.1\n IL_0024: ldfld \"\"int Point.k__BackingField\"\"\n IL_0029: callvirt \"\"bool System.Collections.Generic.EqualityComparer.Equals(int, int)\"\"\n IL_002e: ret\n IL_002f: ldc.i4.0\n IL_0030: ret\n}\");\n }\n\n [Fact]\n public void StructRecord2()\n {\n var src = @\"\nusing System;\nrecord struct S(int X, int Y)\n{\n public static void Main()\n {\n var s1 = new S(0, 1);\n var s2 = new S(0, 1);\n Console.WriteLine(s1.X);\n Console.WriteLine(s1.Y);\n Console.WriteLine(s1.Equals(s2));\n Console.WriteLine(s1.Equals(new S(1, 0)));\n }\n}\";\n var verifier = CompileAndVerify(src, expectedOutput: @\"0\n1\nTrue\nFalse\").VerifyDiagnostics();\n }\n\n [Fact]\n public void StructRecord3()\n {\n var src = @\"\nusing System;\nrecord struct S(int X, int Y)\n{\n public bool Equals(S s) => false;\n public static void Main()\n {\n var s1 = new S(0, 1);\n Console.WriteLine(s1.Equals(s1));\n }\n}\";\n var verifier = CompileAndVerify(src, expectedOutput: @\"False\")\n .VerifyDiagnostics(\n // (5,17): warning CS8851: 'S' defines 'Equals' but not 'GetHashCode'\n // public bool Equals(S s) => false;\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"S\").WithLocation(5, 17));\n\n verifier.VerifyIL(\"S.Main\", @\"\n{\n // Code size 23 (0x17)\n .maxstack 3\n .locals init (S V_0) //s1\n IL_0000: ldloca.s V_0\n IL_0002: ldc.i4.0\n IL_0003: ldc.i4.1\n IL_0004: call \"\"S..ctor(int, int)\"\"\n IL_0009: ldloca.s V_0\n IL_000b: ldloc.0\n IL_000c: call \"\"bool S.Equals(S)\"\"\n IL_0011: call \"\"void System.Console.WriteLine(bool)\"\"\n IL_0016: ret\n}\");\n }\n\n [Fact]\n public void StructRecord5()\n {\n var src = @\"\nusing System;\nrecord struct S(int X, int Y)\n{\n public bool Equals(S s)\n {\n Console.Write(\"\"s\"\");\n return true;\n }\n public static void Main()\n {\n var s1 = new S(0, 1);\n s1.Equals((object)s1);\n s1.Equals(s1);\n }\n}\";\n CompileAndVerify(src, expectedOutput: @\"ss\")\n .VerifyDiagnostics(\n // (5,17): warning CS8851: 'S' defines 'Equals' but not 'GetHashCode'\n // public bool Equals(S s)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"S\").WithLocation(5, 17));\n }\n\n [Fact]\n public void StructRecordDefaultCtor()\n {\n const string src = @\"\npublic record struct S(int X);\";\n\n const string src2 = @\"\nclass C\n{\n public S M() => new S();\n}\";\n var comp = CreateCompilation(src + src2);\n comp.VerifyDiagnostics();\n\n comp = CreateCompilation(src);\n var comp2 = CreateCompilation(src2, references: new[] { comp.EmitToImageReference() });\n comp2.VerifyDiagnostics();\n }\n\n [Fact]\n public void Equality_01()\n {\n var source =\n@\"using static System.Console;\nrecord struct S;\n\nclass Program\n{\n static void Main()\n {\n var x = new S();\n var y = new S();\n WriteLine(x.Equals(y));\n WriteLine(((object)x).Equals(y));\n }\n}\";\n var comp = CreateCompilation(source, parseOptions: TestOptions.RegularPreview, options: TestOptions.ReleaseExe);\n\n var verifier = CompileAndVerify(comp, expectedOutput: @\"True\nTrue\").VerifyDiagnostics();\n\n verifier.VerifyIL(\"S.Equals(S)\", @\"\n{\n // Code size 2 (0x2)\n .maxstack 1\n IL_0000: ldc.i4.1\n IL_0001: ret\n}\");\n verifier.VerifyIL(\"S.Equals(object)\", @\"\n{\n // Code size 23 (0x17)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: isinst \"\"S\"\"\n IL_0006: brfalse.s IL_0015\n IL_0008: ldarg.0\n IL_0009: ldarg.1\n IL_000a: unbox.any \"\"S\"\"\n IL_000f: call \"\"readonly bool S.Equals(S)\"\"\n IL_0014: ret\n IL_0015: ldc.i4.0\n IL_0016: ret\n}\");\n }\n\n [Fact]\n public void RecordStructLanguageVersion()\n {\n var src1 = @\"\nstruct Point(int x, int y);\n\";\n var src2 = @\"\nrecord struct Point { }\n\";\n var src3 = @\"\nrecord struct Point(int x, int y);\n\";\n\n var comp = CreateCompilation(new[] { src1, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular9, options: TestOptions.ReleaseDll);\n comp.VerifyDiagnostics(\n // (2,13): error CS1514: { expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_LbraceExpected, \"(\").WithLocation(2, 13),\n // (2,13): error CS1513: } expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_RbraceExpected, \"(\").WithLocation(2, 13),\n // (2,13): error CS8803: Top-level statements must precede namespace and type declarations.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_TopLevelStatementAfterNamespaceOrType, \"(int x, int y);\").WithLocation(2, 13),\n // (2,13): error CS8805: Program using top-level statements must be an executable.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_SimpleProgramNotAnExecutable, \"(int x, int y);\").WithLocation(2, 13),\n // (2,13): error CS0201: Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_IllegalStatement, \"(int x, int y)\").WithLocation(2, 13),\n // (2,14): error CS8185: A declaration is not allowed in this context.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_DeclarationExpressionNotPermitted, \"int x\").WithLocation(2, 14),\n // (2,14): error CS0165: Use of unassigned local variable 'x'\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_UseDefViolation, \"int x\").WithArguments(\"x\").WithLocation(2, 14),\n // (2,21): error CS8185: A declaration is not allowed in this context.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_DeclarationExpressionNotPermitted, \"int y\").WithLocation(2, 21),\n // (2,21): error CS0165: Use of unassigned local variable 'y'\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_UseDefViolation, \"int y\").WithArguments(\"y\").WithLocation(2, 21)\n );\n\n comp = CreateCompilation(new[] { src2, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular9, options: TestOptions.ReleaseDll);\n comp.VerifyDiagnostics(\n // (2,8): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct Point { }\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(2, 8)\n );\n\n comp = CreateCompilation(new[] { src3, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular9, options: TestOptions.ReleaseDll);\n comp.VerifyDiagnostics(\n // (2,8): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct Point { }\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(2, 8)\n );\n\n comp = CreateCompilation(new[] { src1, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular10, options: TestOptions.ReleaseDll);\n comp.VerifyDiagnostics(\n // (2,13): error CS1514: { expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_LbraceExpected, \"(\").WithLocation(2, 13),\n // (2,13): error CS1513: } expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_RbraceExpected, \"(\").WithLocation(2, 13),\n // (2,13): error CS8803: Top-level statements must precede namespace and type declarations.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_TopLevelStatementAfterNamespaceOrType, \"(int x, int y);\").WithLocation(2, 13),\n // (2,13): error CS8805: Program using top-level statements must be an executable.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_SimpleProgramNotAnExecutable, \"(int x, int y);\").WithLocation(2, 13),\n // (2,13): error CS0201: Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_IllegalStatement, \"(int x, int y)\").WithLocation(2, 13),\n // (2,14): error CS8185: A declaration is not allowed in this context.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_DeclarationExpressionNotPermitted, \"int x\").WithLocation(2, 14),\n // (2,14): error CS0165: Use of unassigned local variable 'x'\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_UseDefViolation, \"int x\").WithArguments(\"x\").WithLocation(2, 14),\n // (2,21): error CS8185: A declaration is not allowed in this context.\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_DeclarationExpressionNotPermitted, \"int y\").WithLocation(2, 21),\n // (2,21): error CS0165: Use of unassigned local variable 'y'\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_UseDefViolation, \"int y\").WithArguments(\"y\").WithLocation(2, 21)\n );\n\n comp = CreateCompilation(new[] { src2, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular10, options: TestOptions.ReleaseDll);\n comp.VerifyDiagnostics();\n\n comp = CreateCompilation(new[] { src3, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular10, options: TestOptions.ReleaseDll);\n comp.VerifyDiagnostics();\n }\n\n [Fact]\n public void RecordStructLanguageVersion_Nested()\n {\n var src1 = @\"\nclass C\n{\n struct Point(int x, int y);\n}\n\";\n var src2 = @\"\nclass D\n{\n record struct Point { }\n}\n\";\n var src3 = @\"\nstruct E\n{\n record struct Point(int x, int y);\n}\n\";\n var src4 = @\"\nnamespace NS\n{\n record struct Point { }\n}\n\";\n var comp = CreateCompilation(src1, parseOptions: TestOptions.Regular9);\n comp.VerifyDiagnostics(\n // (4,17): error CS1514: { expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_LbraceExpected, \"(\").WithLocation(4, 17),\n // (4,17): error CS1513: } expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_RbraceExpected, \"(\").WithLocation(4, 17),\n // (4,31): error CS1519: Invalid token ';' in class, record, struct, or interface member declaration\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_InvalidMemberDecl, \";\").WithArguments(\";\").WithLocation(4, 31),\n // (4,31): error CS1519: Invalid token ';' in class, record, struct, or interface member declaration\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_InvalidMemberDecl, \";\").WithArguments(\";\").WithLocation(4, 31)\n );\n\n comp = CreateCompilation(new[] { src2, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular9);\n comp.VerifyDiagnostics(\n // (4,12): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct Point { }\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(4, 12)\n );\n\n comp = CreateCompilation(new[] { src3, IsExternalInitTypeDefinition }, parseOptions: TestOptions.Regular9);\n comp.VerifyDiagnostics(\n // (4,12): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(4, 12)\n );\n\n comp = CreateCompilation(src4, parseOptions: TestOptions.Regular9);\n comp.VerifyDiagnostics(\n // (4,12): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct Point { }\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(4, 12)\n );\n\n comp = CreateCompilation(src1);\n comp.VerifyDiagnostics(\n // (4,17): error CS1514: { expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_LbraceExpected, \"(\").WithLocation(4, 17),\n // (4,17): error CS1513: } expected\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_RbraceExpected, \"(\").WithLocation(4, 17),\n // (4,31): error CS1519: Invalid token ';' in class, record, struct, or interface member declaration\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_InvalidMemberDecl, \";\").WithArguments(\";\").WithLocation(4, 31),\n // (4,31): error CS1519: Invalid token ';' in class, record, struct, or interface member declaration\n // struct Point(int x, int y);\n Diagnostic(ErrorCode.ERR_InvalidMemberDecl, \";\").WithArguments(\";\").WithLocation(4, 31)\n );\n\n comp = CreateCompilation(src2);\n comp.VerifyDiagnostics();\n\n comp = CreateCompilation(src3);\n comp.VerifyDiagnostics();\n\n comp = CreateCompilation(src4);\n comp.VerifyDiagnostics();\n }\n\n [Fact]\n public void TypeDeclaration_IsStruct()\n {\n var src = @\"\nrecord struct Point(int x, int y);\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n\n CompileAndVerify(comp, symbolValidator: validateModule, sourceSymbolValidator: validateModule);\n Assert.True(SyntaxFacts.IsTypeDeclaration(SyntaxKind.RecordStructDeclaration));\n\n static void validateModule(ModuleSymbol module)\n {\n var isSourceSymbol = module is SourceModuleSymbol;\n\n var point = module.GlobalNamespace.GetTypeMember(\"Point\");\n Assert.True(point.IsValueType);\n Assert.False(point.IsReferenceType);\n Assert.False(point.IsRecord);\n Assert.Equal(TypeKind.Struct, point.TypeKind);\n Assert.Equal(SpecialType.System_ValueType, point.BaseTypeNoUseSiteDiagnostics.SpecialType);\n Assert.Equal(\"Point\", point.ToTestDisplayString());\n\n if (isSourceSymbol)\n {\n Assert.True(point is SourceNamedTypeSymbol);\n Assert.True(point.IsRecordStruct);\n Assert.True(point.GetPublicSymbol().IsRecord);\n Assert.Equal(\"record struct Point\", point.ToDisplayString(SymbolDisplayFormat.TestFormat.AddKindOptions(SymbolDisplayKindOptions.IncludeTypeKeyword)));\n }\n else\n {\n Assert.True(point is PENamedTypeSymbol);\n Assert.False(point.IsRecordStruct);\n Assert.False(point.GetPublicSymbol().IsRecord);\n Assert.Equal(\"struct Point\", point.ToDisplayString(SymbolDisplayFormat.TestFormat.AddKindOptions(SymbolDisplayKindOptions.IncludeTypeKeyword)));\n }\n }\n }\n\n [Fact]\n public void TypeDeclaration_IsStruct_InConstraints()\n {\n var src = @\"\nrecord struct Point(int x, int y);\n\nclass C where T : struct\n{\n void M(C c) { }\n}\n\nclass C2 where T : new()\n{\n void M(C2 c) { }\n}\n\nclass C3 where T : class\n{\n void M(C3 c) { } // 1\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (16,22): error CS0452: The type 'Point' must be a reference type in order to use it as parameter 'T' in the generic type or method 'C3'\n // void M(C3 c) { } // 1\n Diagnostic(ErrorCode.ERR_RefConstraintNotSatisfied, \"c\").WithArguments(\"C3\", \"T\", \"Point\").WithLocation(16, 22)\n );\n }\n\n [Fact]\n public void TypeDeclaration_IsStruct_Unmanaged()\n {\n var src = @\"\nrecord struct Point(int x, int y);\nrecord struct Point2(string x, string y);\n\nclass C where T : unmanaged\n{\n void M(C c) { }\n void M2(C c) { } // 1\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (8,23): error CS8377: The type 'Point2' must be a non-nullable value type, along with all fields at any level of nesting, in order to use it as parameter 'T' in the generic type or method 'C'\n // void M2(C c) { } // 1\n Diagnostic(ErrorCode.ERR_UnmanagedConstraintNotSatisfied, \"c\").WithArguments(\"C\", \"T\", \"Point2\").WithLocation(8, 23)\n );\n }\n\n [Fact]\n public void IsRecord_Generic()\n {\n var src = @\"\nrecord struct Point(T x, T y);\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n\n CompileAndVerify(comp, symbolValidator: validateModule, sourceSymbolValidator: validateModule);\n\n static void validateModule(ModuleSymbol module)\n {\n var isSourceSymbol = module is SourceModuleSymbol;\n\n var point = module.GlobalNamespace.GetTypeMember(\"Point\");\n Assert.True(point.IsValueType);\n Assert.False(point.IsReferenceType);\n Assert.False(point.IsRecord);\n Assert.Equal(TypeKind.Struct, point.TypeKind);\n Assert.Equal(SpecialType.System_ValueType, point.BaseTypeNoUseSiteDiagnostics.SpecialType);\n Assert.True(SyntaxFacts.IsTypeDeclaration(SyntaxKind.RecordStructDeclaration));\n\n if (isSourceSymbol)\n {\n Assert.True(point is SourceNamedTypeSymbol);\n Assert.True(point.IsRecordStruct);\n Assert.True(point.GetPublicSymbol().IsRecord);\n }\n else\n {\n Assert.True(point is PENamedTypeSymbol);\n Assert.False(point.IsRecordStruct);\n Assert.False(point.GetPublicSymbol().IsRecord);\n }\n }\n }\n\n [Fact]\n public void IsRecord_Retargeting()\n {\n var src = @\"\npublic record struct Point(int x, int y);\n\";\n var comp = CreateCompilation(src, targetFramework: TargetFramework.Mscorlib40);\n var comp2 = CreateCompilation(\"\", targetFramework: TargetFramework.Mscorlib46, references: new[] { comp.ToMetadataReference() });\n var point = comp2.GlobalNamespace.GetTypeMember(\"Point\");\n\n Assert.Equal(\"Point\", point.ToTestDisplayString());\n Assert.IsType(point);\n Assert.True(point.IsRecordStruct);\n Assert.True(point.GetPublicSymbol().IsRecord);\n }\n\n [Fact]\n public void IsRecord_AnonymousType()\n {\n var src = @\"\nclass C\n{\n void M()\n {\n var x = new { X = 1 };\n }\n}\n\";\n var comp = CreateCompilation(src);\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree, ignoreAccessibility: false);\n var creation = tree.GetRoot().DescendantNodes().OfType().Single();\n var type = model.GetTypeInfo(creation).Type!;\n\n Assert.Equal(\"\", type.ToTestDisplayString());\n Assert.IsType(((Symbols.PublicModel.NonErrorNamedTypeSymbol)type).UnderlyingNamedTypeSymbol);\n Assert.False(type.IsRecord);\n }\n\n [Fact]\n public void IsRecord_ErrorType()\n {\n var src = @\"\nclass C\n{\n Error M() => throw null;\n}\n\";\n var comp = CreateCompilation(src);\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree, ignoreAccessibility: false);\n var method = tree.GetRoot().DescendantNodes().OfType().Single();\n var type = model.GetDeclaredSymbol(method)!.ReturnType;\n\n Assert.Equal(\"Error\", type.ToTestDisplayString());\n Assert.IsType(((Symbols.PublicModel.ErrorTypeSymbol)type).UnderlyingNamedTypeSymbol);\n Assert.False(type.IsRecord);\n }\n\n [Fact]\n public void IsRecord_Pointer()\n {\n var src = @\"\nclass C\n{\n int* M() => throw null;\n}\n\";\n var comp = CreateCompilation(src, options: TestOptions.UnsafeReleaseDll);\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree, ignoreAccessibility: false);\n var method = tree.GetRoot().DescendantNodes().OfType().Single();\n var type = model.GetDeclaredSymbol(method)!.ReturnType;\n\n Assert.Equal(\"System.Int32*\", type.ToTestDisplayString());\n Assert.IsType(((Symbols.PublicModel.PointerTypeSymbol)type).UnderlyingTypeSymbol);\n Assert.False(type.IsRecord);\n }\n\n [Fact]\n public void IsRecord_Dynamic()\n {\n var src = @\"\nclass C\n{\n void M(dynamic d)\n {\n }\n}\n\";\n var comp = CreateCompilation(src);\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree, ignoreAccessibility: false);\n var method = tree.GetRoot().DescendantNodes().OfType().Single();\n var type = model.GetDeclaredSymbol(method)!.GetParameterType(0);\n\n Assert.Equal(\"dynamic\", type.ToTestDisplayString());\n Assert.IsType(((Symbols.PublicModel.DynamicTypeSymbol)type).UnderlyingTypeSymbol);\n Assert.False(type.IsRecord);\n }\n\n [Fact]\n public void TypeDeclaration_MayNotHaveBaseType()\n {\n var src = @\"\nrecord struct Point(int x, int y) : object;\nrecord struct Point2(int x, int y) : System.ValueType;\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,37): error CS0527: Type 'object' in interface list is not an interface\n // record struct Point(int x, int y) : object;\n Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, \"object\").WithArguments(\"object\").WithLocation(2, 37),\n // (3,38): error CS0527: Type 'ValueType' in interface list is not an interface\n // record struct Point2(int x, int y) : System.ValueType;\n Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, \"System.ValueType\").WithArguments(\"System.ValueType\").WithLocation(3, 38)\n );\n }\n\n [Fact]\n public void TypeDeclaration_MayNotHaveTypeConstraintsWithoutTypeParameters()\n {\n var src = @\"\nrecord struct Point(int x, int y) where T : struct;\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,35): error CS0080: Constraints are not allowed on non-generic declarations\n // record struct Point(int x, int y) where T : struct;\n Diagnostic(ErrorCode.ERR_ConstraintOnlyAllowedOnGenericDecl, \"where\").WithLocation(2, 35)\n );\n }\n\n [Fact]\n public void TypeDeclaration_AllowedModifiers()\n {\n var src = @\"\nreadonly partial record struct S1;\npublic record struct S2;\ninternal record struct S3;\n\npublic class Base\n{\n public int S6;\n}\npublic class C : Base\n{\n private protected record struct S4;\n protected internal record struct S5;\n new record struct S6;\n}\nunsafe record struct S7;\n\";\n\n var comp = CreateCompilation(src, parseOptions: TestOptions.RegularPreview, options: TestOptions.UnsafeDebugDll);\n comp.VerifyDiagnostics();\n Assert.Equal(Accessibility.Internal, comp.GlobalNamespace.GetTypeMember(\"S1\").DeclaredAccessibility);\n Assert.Equal(Accessibility.Public, comp.GlobalNamespace.GetTypeMember(\"S2\").DeclaredAccessibility);\n Assert.Equal(Accessibility.Internal, comp.GlobalNamespace.GetTypeMember(\"S3\").DeclaredAccessibility);\n Assert.Equal(Accessibility.ProtectedAndInternal, comp.GlobalNamespace.GetTypeMember(\"C\").GetTypeMember(\"S4\").DeclaredAccessibility);\n Assert.Equal(Accessibility.ProtectedOrInternal, comp.GlobalNamespace.GetTypeMember(\"C\").GetTypeMember(\"S5\").DeclaredAccessibility);\n }\n\n [Fact]\n public void TypeDeclaration_DisallowedModifiers()\n {\n var src = @\"\nabstract record struct S1;\nvolatile record struct S2;\nextern record struct S3;\nvirtual record struct S4;\noverride record struct S5;\nasync record struct S6;\nref record struct S7;\nunsafe record struct S8;\nstatic record struct S9;\nsealed record struct S10;\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,24): error CS0106: The modifier 'abstract' is not valid for this item\n // abstract record struct S1;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S1\").WithArguments(\"abstract\").WithLocation(2, 24),\n // (3,24): error CS0106: The modifier 'volatile' is not valid for this item\n // volatile record struct S2;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S2\").WithArguments(\"volatile\").WithLocation(3, 24),\n // (4,22): error CS0106: The modifier 'extern' is not valid for this item\n // extern record struct S3;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S3\").WithArguments(\"extern\").WithLocation(4, 22),\n // (5,23): error CS0106: The modifier 'virtual' is not valid for this item\n // virtual record struct S4;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S4\").WithArguments(\"virtual\").WithLocation(5, 23),\n // (6,24): error CS0106: The modifier 'override' is not valid for this item\n // override record struct S5;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S5\").WithArguments(\"override\").WithLocation(6, 24),\n // (7,21): error CS0106: The modifier 'async' is not valid for this item\n // async record struct S6;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S6\").WithArguments(\"async\").WithLocation(7, 21),\n // (8,19): error CS0106: The modifier 'ref' is not valid for this item\n // ref record struct S7;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S7\").WithArguments(\"ref\").WithLocation(8, 19),\n // (9,22): error CS0227: Unsafe code may only appear if compiling with /unsafe\n // unsafe record struct S8;\n Diagnostic(ErrorCode.ERR_IllegalUnsafe, \"S8\").WithLocation(9, 22),\n // (10,22): error CS0106: The modifier 'static' is not valid for this item\n // static record struct S9;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S9\").WithArguments(\"static\").WithLocation(10, 22),\n // (11,22): error CS0106: The modifier 'sealed' is not valid for this item\n // sealed record struct S10;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"S10\").WithArguments(\"sealed\").WithLocation(11, 22)\n );\n }\n\n [Fact]\n public void TypeDeclaration_DuplicatesModifiers()\n {\n var src = @\"\npublic public record struct S2;\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,8): error CS1004: Duplicate 'public' modifier\n // public public record struct S2;\n Diagnostic(ErrorCode.ERR_DuplicateModifier, \"public\").WithArguments(\"public\").WithLocation(2, 8)\n );\n }\n\n [Fact]\n public void TypeDeclaration_BeforeTopLevelStatement()\n {\n var src = @\"\nrecord struct S;\nSystem.Console.WriteLine();\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (3,1): error CS8803: Top-level statements must precede namespace and type declarations.\n // System.Console.WriteLine();\n Diagnostic(ErrorCode.ERR_TopLevelStatementAfterNamespaceOrType, \"System.Console.WriteLine();\").WithLocation(3, 1)\n );\n }\n\n [Fact]\n public void TypeDeclaration_WithTypeParameters()\n {\n var src = @\"\nS local = default;\nlocal.ToString();\n\nrecord struct S;\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n Assert.Equal(new[] { \"T\" }, comp.GlobalNamespace.GetTypeMember(\"S\").TypeParameters.ToTestDisplayStrings());\n }\n\n [Fact]\n public void TypeDeclaration_AllowedModifiersForMembers()\n {\n var src = @\"\nrecord struct S\n{\n protected int Property { get; set; } // 1\n internal protected string field; // 2, 3\n abstract void M(); // 4\n virtual void M2() { } // 5\n}\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (4,19): error CS0666: 'S.Property': new protected member declared in struct\n // protected int Property { get; set; } // 1\n Diagnostic(ErrorCode.ERR_ProtectedInStruct, \"Property\").WithArguments(\"S.Property\").WithLocation(4, 19),\n // (5,31): error CS0666: 'S.field': new protected member declared in struct\n // internal protected string field; // 2, 3\n Diagnostic(ErrorCode.ERR_ProtectedInStruct, \"field\").WithArguments(\"S.field\").WithLocation(5, 31),\n // (5,31): warning CS0649: Field 'S.field' is never assigned to, and will always have its default value null\n // internal protected string field; // 2, 3\n Diagnostic(ErrorCode.WRN_UnassignedInternalField, \"field\").WithArguments(\"S.field\", \"null\").WithLocation(5, 31),\n // (6,19): error CS0621: 'S.M()': virtual or abstract members cannot be private\n // abstract void M(); // 4\n Diagnostic(ErrorCode.ERR_VirtualPrivate, \"M\").WithArguments(\"S.M()\").WithLocation(6, 19),\n // (7,18): error CS0621: 'S.M2()': virtual or abstract members cannot be private\n // virtual void M2() { } // 5\n Diagnostic(ErrorCode.ERR_VirtualPrivate, \"M2\").WithArguments(\"S.M2()\").WithLocation(7, 18)\n );\n }\n\n [Fact]\n public void TypeDeclaration_ImplementInterface()\n {\n var src = @\"\nI i = (I)default(S);\nSystem.Console.Write(i.M(\"\"four\"\"));\n\nI i2 = (I)default(S2);\nSystem.Console.Write(i2.M(\"\"four\"\"));\n\ninterface I\n{\n int M(string s);\n}\npublic record struct S : I\n{\n public int M(string s)\n => s.Length;\n}\npublic record struct S2 : I\n{\n int I.M(string s)\n => s.Length + 1;\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n\n CompileAndVerify(comp, expectedOutput: \"45\");\n\n AssertEx.Equal(new[] {\n \"System.Int32 S.M(System.String s)\",\n \"readonly System.String S.ToString()\",\n \"readonly System.Boolean S.PrintMembers(System.Text.StringBuilder builder)\",\n \"System.Boolean S.op_Inequality(S left, S right)\",\n \"System.Boolean S.op_Equality(S left, S right)\",\n \"readonly System.Int32 S.GetHashCode()\",\n \"readonly System.Boolean S.Equals(System.Object obj)\",\n \"readonly System.Boolean S.Equals(S other)\",\n \"S..ctor()\" },\n comp.GetMember(\"S\").GetMembers().ToTestDisplayStrings());\n }\n\n [Fact]\n public void TypeDeclaration_SatisfiesStructConstraint()\n {\n var src = @\"\nS s = default;\nSystem.Console.Write(M(s));\n\nstatic int M(T t) where T : struct, I\n => t.Property;\n\npublic interface I\n{\n int Property { get; }\n}\npublic record struct S : I\n{\n public int Property => 42;\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n\n CompileAndVerify(comp, expectedOutput: \"42\");\n }\n\n [Fact]\n public void TypeDeclaration_AccessingThis()\n {\n var src = @\"\nS s = new S();\nSystem.Console.Write(s.M());\n\npublic record struct S\n{\n public int Property => 42;\n\n public int M()\n => this.Property;\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n\n var verifier = CompileAndVerify(comp, expectedOutput: \"42\");\n verifier.VerifyIL(\"S.M\", @\"\n{\n // Code size 7 (0x7)\n .maxstack 1\n IL_0000: ldarg.0\n IL_0001: call \"\"int S.Property.get\"\"\n IL_0006: ret\n}\n\");\n }\n\n [Fact]\n public void TypeDeclaration_NoBaseInitializer()\n {\n var src = @\"\npublic record struct S\n{\n public S(int i) : base() { }\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (4,12): error CS0522: 'S': structs cannot call base class constructors\n // public S(int i) : base() { }\n Diagnostic(ErrorCode.ERR_StructWithBaseConstructorCall, \"S\").WithArguments(\"S\").WithLocation(4, 12)\n );\n }\n\n [Fact]\n public void TypeDeclaration_ParameterlessConstructor_01()\n {\n var src =\n@\"record struct S0();\nrecord struct S1;\nrecord struct S2\n{\n public S2() { }\n}\";\n\n var comp = CreateCompilation(src, parseOptions: TestOptions.Regular9);\n comp.VerifyDiagnostics(\n // (1,8): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct S0();\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(1, 8),\n // (2,8): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct S1;\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(2, 8),\n // (3,8): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct S2\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(3, 8),\n // (5,12): error CS8773: Feature 'parameterless struct constructors' is not available in C# 9.0. Please use language version 10.0 or greater.\n // public S2() { }\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"S2\").WithArguments(\"parameterless struct constructors\", \"10.0\").WithLocation(5, 12));\n\n var verifier = CompileAndVerify(src);\n verifier.VerifyIL(\"S0..ctor()\",\n@\"{\n // Code size 1 (0x1)\n .maxstack 0\n IL_0000: ret\n}\");\n verifier.VerifyMissing(\"S1..ctor()\");\n verifier.VerifyIL(\"S2..ctor()\",\n@\"{\n // Code size 1 (0x1)\n .maxstack 0\n IL_0000: ret\n}\");\n }\n\n [Fact]\n public void TypeDeclaration_ParameterlessConstructor_02()\n {\n var src =\n@\"record struct S1\n{\n S1() { }\n}\nrecord struct S2\n{\n internal S2() { }\n}\";\n\n var comp = CreateCompilation(src, parseOptions: TestOptions.Regular9);\n comp.VerifyDiagnostics(\n // (1,8): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct S1\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(1, 8),\n // (3,5): error CS8773: Feature 'parameterless struct constructors' is not available in C# 9.0. Please use language version 10.0 or greater.\n // S1() { }\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"S1\").WithArguments(\"parameterless struct constructors\", \"10.0\").WithLocation(3, 5),\n // (3,5): error CS8938: The parameterless struct constructor must be 'public'.\n // S1() { }\n Diagnostic(ErrorCode.ERR_NonPublicParameterlessStructConstructor, \"S1\").WithLocation(3, 5),\n // (5,8): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // record struct S2\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(5, 8),\n // (7,14): error CS8773: Feature 'parameterless struct constructors' is not available in C# 9.0. Please use language version 10.0 or greater.\n // internal S2() { }\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"S2\").WithArguments(\"parameterless struct constructors\", \"10.0\").WithLocation(7, 14),\n // (7,14): error CS8938: The parameterless struct constructor must be 'public'.\n // internal S2() { }\n Diagnostic(ErrorCode.ERR_NonPublicParameterlessStructConstructor, \"S2\").WithLocation(7, 14));\n\n comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (3,5): error CS8918: The parameterless struct constructor must be 'public'.\n // S1() { }\n Diagnostic(ErrorCode.ERR_NonPublicParameterlessStructConstructor, \"S1\").WithLocation(3, 5),\n // (7,14): error CS8918: The parameterless struct constructor must be 'public'.\n // internal S2() { }\n Diagnostic(ErrorCode.ERR_NonPublicParameterlessStructConstructor, \"S2\").WithLocation(7, 14));\n }\n\n [Fact]\n public void TypeDeclaration_ParameterlessConstructor_OtherConstructors()\n {\n var src = @\"\nrecord struct S1\n{\n public S1() { }\n S1(object o) { } // ok because no record parameter list\n}\nrecord struct S2\n{\n S2(object o) { }\n}\nrecord struct S3()\n{\n S3(object o) { } // 1\n}\nrecord struct S4()\n{\n S4(object o) : this() { }\n}\nrecord struct S5(object o)\n{\n public S5() { } // 2\n}\nrecord struct S6(object o)\n{\n public S6() : this(null) { }\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (13,5): error CS8862: A constructor declared in a record with parameter list must have 'this' constructor initializer.\n // S3(object o) { } // 1\n Diagnostic(ErrorCode.ERR_UnexpectedOrMissingConstructorInitializerInRecord, \"S3\").WithLocation(13, 5),\n // (21,12): error CS8862: A constructor declared in a record with parameter list must have 'this' constructor initializer.\n // public S5() { } // 2\n Diagnostic(ErrorCode.ERR_UnexpectedOrMissingConstructorInitializerInRecord, \"S5\").WithLocation(21, 12)\n );\n }\n\n [Fact]\n public void TypeDeclaration_ParameterlessConstructor_Initializers()\n {\n var src = @\"\nvar s1 = new S1();\nvar s2 = new S2(null);\nvar s2b = new S2();\nvar s3 = new S3();\nvar s4 = new S4(new object());\nvar s5 = new S5();\nvar s6 = new S6(\"\"s6.other\"\");\n\nSystem.Console.Write((s1.field, s2.field, s2b.field is null, s3.field, s4.field, s5.field, s6.field, s6.other));\n\nrecord struct S1\n{\n public string field = \"\"s1\"\";\n public S1() { }\n}\nrecord struct S2\n{\n public string field = \"\"s2\"\";\n public S2(object o) { }\n}\nrecord struct S3()\n{\n public string field = \"\"s3\"\";\n}\nrecord struct S4\n{\n public string field = \"\"s4\"\";\n public S4(object o) : this() { }\n}\nrecord struct S5()\n{\n public string field = \"\"s5\"\";\n public S5(object o) : this() { }\n}\nrecord struct S6(string other)\n{\n public string field = \"\"s6.field\"\";\n public S6() : this(\"\"ignored\"\") { }\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"(s1, s2, True, s3, s4, s5, s6.field, s6.other)\");\n }\n\n [Fact]\n public void TypeDeclaration_InstanceInitializers()\n {\n var src = @\"\npublic record struct S\n{\n public int field = 42;\n public int Property { get; set; } = 43;\n}\n\";\n\n var comp = CreateCompilation(src, parseOptions: TestOptions.Regular9);\n comp.VerifyDiagnostics(\n // (2,15): error CS8773: Feature 'record structs' is not available in C# 9.0. Please use language version 10.0 or greater.\n // public record struct S\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"struct\").WithArguments(\"record structs\", \"10.0\").WithLocation(2, 15),\n // (4,16): error CS8773: Feature 'struct field initializers' is not available in C# 9.0. Please use language version 10.0 or greater.\n // public int field = 42;\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"field\").WithArguments(\"struct field initializers\", \"10.0\").WithLocation(4, 16),\n // (5,16): error CS8773: Feature 'struct field initializers' is not available in C# 9.0. Please use language version 10.0 or greater.\n // public int Property { get; set; } = 43;\n Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, \"Property\").WithArguments(\"struct field initializers\", \"10.0\").WithLocation(5, 16));\n\n comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n }\n\n [Fact]\n public void TypeDeclaration_NoDestructor()\n {\n var src = @\"\npublic record struct S\n{\n ~S() { }\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (4,6): error CS0575: Only class types can contain destructors\n // ~S() { }\n Diagnostic(ErrorCode.ERR_OnlyClassesCanContainDestructors, \"S\").WithArguments(\"S.~S()\").WithLocation(4, 6)\n );\n }\n\n [Fact]\n public void TypeDeclaration_DifferentPartials()\n {\n var src = @\"\npartial record struct S1;\npartial struct S1 { }\n\npartial struct S2 { }\npartial record struct S2;\n\npartial record struct S3;\npartial record S3 { }\n\npartial record struct S4;\npartial record class S4 { }\n\npartial record struct S5;\npartial class S5 { }\n\npartial record struct S6;\npartial interface S6 { }\n\npartial record class C1;\npartial struct C1 { }\n\npartial record class C2;\npartial record struct C2 { }\n\npartial record class C3 { }\npartial record C3;\n\npartial record class C4;\npartial class C4 { }\n\npartial record class C5;\npartial interface C5 { }\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (3,16): error CS0261: Partial declarations of 'S1' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial struct S1 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"S1\").WithArguments(\"S1\").WithLocation(3, 16),\n // (6,23): error CS0261: Partial declarations of 'S2' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial record struct S2;\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"S2\").WithArguments(\"S2\").WithLocation(6, 23),\n // (9,16): error CS0261: Partial declarations of 'S3' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial record S3 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"S3\").WithArguments(\"S3\").WithLocation(9, 16),\n // (12,22): error CS0261: Partial declarations of 'S4' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial record class S4 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"S4\").WithArguments(\"S4\").WithLocation(12, 22),\n // (15,15): error CS0261: Partial declarations of 'S5' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial class S5 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"S5\").WithArguments(\"S5\").WithLocation(15, 15),\n // (18,19): error CS0261: Partial declarations of 'S6' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial interface S6 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"S6\").WithArguments(\"S6\").WithLocation(18, 19),\n // (21,16): error CS0261: Partial declarations of 'C1' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial struct C1 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"C1\").WithArguments(\"C1\").WithLocation(21, 16),\n // (24,23): error CS0261: Partial declarations of 'C2' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial record struct C2 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"C2\").WithArguments(\"C2\").WithLocation(24, 23),\n // (30,15): error CS0261: Partial declarations of 'C4' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial class C4 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"C4\").WithArguments(\"C4\").WithLocation(30, 15),\n // (33,19): error CS0261: Partial declarations of 'C5' must be all classes, all record classes, all structs, all record structs, or all interfaces\n // partial interface C5 { }\n Diagnostic(ErrorCode.ERR_PartialTypeKindConflict, \"C5\").WithArguments(\"C5\").WithLocation(33, 19)\n );\n }\n\n [Fact]\n public void PartialRecord_OnlyOnePartialHasParameterList()\n {\n var src = @\"\npartial record struct S(int i);\npartial record struct S(int i);\n\npartial record struct S2(int i);\npartial record struct S2();\n\npartial record struct S3();\npartial record struct S3();\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (3,24): error CS8863: Only a single record partial declaration may have a parameter list\n // partial record struct S(int i);\n Diagnostic(ErrorCode.ERR_MultipleRecordParameterLists, \"(int i)\").WithLocation(3, 24),\n // (6,25): error CS8863: Only a single record partial declaration may have a parameter list\n // partial record struct S2();\n Diagnostic(ErrorCode.ERR_MultipleRecordParameterLists, \"()\").WithLocation(6, 25),\n // (9,25): error CS8863: Only a single record partial declaration may have a parameter list\n // partial record struct S3();\n Diagnostic(ErrorCode.ERR_MultipleRecordParameterLists, \"()\").WithLocation(9, 25)\n );\n }\n\n [Fact]\n public void PartialRecord_ParametersInScopeOfBothParts()\n {\n var src = @\"\nvar c = new C(2);\nSystem.Console.Write((c.P1, c.P2));\n\npublic partial record struct C(int X)\n{\n public int P1 { get; set; } = X;\n}\npublic partial record struct C\n{\n public int P2 { get; set; } = X;\n}\n\";\n var comp = CreateCompilation(src);\n CompileAndVerify(comp, expectedOutput: \"(2, 2)\", verify: Verification.Skipped /* init-only */)\n .VerifyDiagnostics(\n // (5,30): warning CS0282: There is no defined ordering between fields in multiple declarations of partial struct 'C'. To specify an ordering, all instance fields must be in the same declaration.\n // public partial record struct C(int X)\n Diagnostic(ErrorCode.WRN_SequentialOnPartialClass, \"C\").WithArguments(\"C\").WithLocation(5, 30)\n );\n }\n\n [Fact]\n public void PartialRecord_DuplicateMemberNames()\n {\n var src = @\"\npublic partial record struct C(int X)\n{\n public void M(int i) { }\n}\npublic partial record struct C\n{\n public void M(string s) { }\n}\n\";\n var comp = CreateCompilation(src);\n var expectedMemberNames = new string[]\n {\n \".ctor\",\n \"k__BackingField\",\n \"get_X\",\n \"set_X\",\n \"X\",\n \"M\",\n \"M\",\n \"ToString\",\n \"PrintMembers\",\n \"op_Inequality\",\n \"op_Equality\",\n \"GetHashCode\",\n \"Equals\",\n \"Equals\",\n \"Deconstruct\",\n \".ctor\",\n };\n AssertEx.Equal(expectedMemberNames, comp.GetMember(\"C\").GetPublicSymbol().MemberNames);\n }\n\n [Fact]\n public void RecordInsideGenericType()\n {\n var src = @\"\nvar c = new C.Nested(2);\nSystem.Console.Write(c.T);\n\npublic class C\n{\n public record struct Nested(T T);\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"2\");\n }\n\n [Fact]\n public void PositionalMemberModifiers_RefOrOut()\n {\n var src = @\"\nrecord struct R(ref int P1, out int P2);\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics(\n // (2,15): error CS0177: The out parameter 'P2' must be assigned to before control leaves the current method\n // record struct R(ref int P1, out int P2);\n Diagnostic(ErrorCode.ERR_ParamUnassigned, \"R\").WithArguments(\"P2\").WithLocation(2, 15),\n // (2,17): error CS0631: ref and out are not valid in this context\n // record struct R(ref int P1, out int P2);\n Diagnostic(ErrorCode.ERR_IllegalRefParam, \"ref\").WithLocation(2, 17),\n // (2,29): error CS0631: ref and out are not valid in this context\n // record struct R(ref int P1, out int P2);\n Diagnostic(ErrorCode.ERR_IllegalRefParam, \"out\").WithLocation(2, 29)\n );\n }\n\n [Fact, WorkItem(45008, \"https://github.com/dotnet/roslyn/issues/45008\")]\n public void PositionalMemberModifiers_This()\n {\n var src = @\"\nrecord struct R(this int i);\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics(\n // (2,17): error CS0027: Keyword 'this' is not available in the current context\n // record struct R(this int i);\n Diagnostic(ErrorCode.ERR_ThisInBadContext, \"this\").WithLocation(2, 17)\n );\n }\n\n [Fact, WorkItem(45591, \"https://github.com/dotnet/roslyn/issues/45591\")]\n public void Clone_DisallowedInSource()\n {\n var src = @\"\nrecord struct C1(string Clone); // 1\nrecord struct C2\n{\n string Clone; // 2\n}\nrecord struct C3\n{\n string Clone { get; set; } // 3\n}\nrecord struct C5\n{\n void Clone() { } // 4\n void Clone(int i) { } // 5\n}\nrecord struct C6\n{\n class Clone { } // 6\n}\nrecord struct C7\n{\n delegate void Clone(); // 7\n}\nrecord struct C8\n{\n event System.Action Clone; // 8\n}\nrecord struct Clone\n{\n Clone(int i) => throw null;\n}\nrecord struct C9 : System.ICloneable\n{\n object System.ICloneable.Clone() => throw null;\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,25): error CS8859: Members named 'Clone' are disallowed in records.\n // record struct C1(string Clone); // 1\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(2, 25),\n // (5,12): error CS8859: Members named 'Clone' are disallowed in records.\n // string Clone; // 2\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(5, 12),\n // (5,12): warning CS0169: The field 'C2.Clone' is never used\n // string Clone; // 2\n Diagnostic(ErrorCode.WRN_UnreferencedField, \"Clone\").WithArguments(\"C2.Clone\").WithLocation(5, 12),\n // (9,12): error CS8859: Members named 'Clone' are disallowed in records.\n // string Clone { get; set; } // 3\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(9, 12),\n // (13,10): error CS8859: Members named 'Clone' are disallowed in records.\n // void Clone() { } // 4\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(13, 10),\n // (14,10): error CS8859: Members named 'Clone' are disallowed in records.\n // void Clone(int i) { } // 5\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(14, 10),\n // (18,11): error CS8859: Members named 'Clone' are disallowed in records.\n // class Clone { } // 6\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(18, 11),\n // (22,19): error CS8859: Members named 'Clone' are disallowed in records.\n // delegate void Clone(); // 7\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(22, 19),\n // (26,25): error CS8859: Members named 'Clone' are disallowed in records.\n // event System.Action Clone; // 8\n Diagnostic(ErrorCode.ERR_CloneDisallowedInRecord, \"Clone\").WithLocation(26, 25),\n // (26,25): warning CS0067: The event 'C8.Clone' is never used\n // event System.Action Clone; // 8\n Diagnostic(ErrorCode.WRN_UnreferencedEvent, \"Clone\").WithArguments(\"C8.Clone\").WithLocation(26, 25)\n );\n }\n\n [ConditionalFact(typeof(DesktopOnly), Reason = ConditionalSkipReason.RestrictedTypesNeedDesktop)]\n [WorkItem(48115, \"https://github.com/dotnet/roslyn/issues/48115\")]\n public void RestrictedTypesAndPointerTypes()\n {\n var src = @\"\nclass C { }\nstatic class C2 { }\nref struct RefLike{}\n\nunsafe record struct C( // 1\n int* P1, // 2\n int*[] P2, // 3\n C P3,\n delegate* P4, // 4\n void P5, // 5\n C2 P6, // 6, 7\n System.ArgIterator P7, // 8\n System.TypedReference P8, // 9\n RefLike P9); // 10\n\";\n\n var comp = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.UnsafeDebugDll);\n comp.VerifyEmitDiagnostics(\n // (6,22): error CS0721: 'C2': static types cannot be used as parameters\n // unsafe record struct C( // 1\n Diagnostic(ErrorCode.ERR_ParameterIsStaticClass, \"C\").WithArguments(\"C2\").WithLocation(6, 22),\n // (7,10): error CS8908: The type 'int*' may not be used for a field of a record.\n // int* P1, // 2\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"P1\").WithArguments(\"int*\").WithLocation(7, 10),\n // (8,12): error CS8908: The type 'int*[]' may not be used for a field of a record.\n // int*[] P2, // 3\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"P2\").WithArguments(\"int*[]\").WithLocation(8, 12),\n // (10,25): error CS8908: The type 'delegate*' may not be used for a field of a record.\n // delegate* P4, // 4\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"P4\").WithArguments(\"delegate*\").WithLocation(10, 25),\n // (11,5): error CS1536: Invalid parameter type 'void'\n // void P5, // 5\n Diagnostic(ErrorCode.ERR_NoVoidParameter, \"void\").WithLocation(11, 5),\n // (12,8): error CS0722: 'C2': static types cannot be used as return types\n // C2 P6, // 6, 7\n Diagnostic(ErrorCode.ERR_ReturnTypeIsStaticClass, \"P6\").WithArguments(\"C2\").WithLocation(12, 8),\n // (12,8): error CS0721: 'C2': static types cannot be used as parameters\n // C2 P6, // 6, 7\n Diagnostic(ErrorCode.ERR_ParameterIsStaticClass, \"P6\").WithArguments(\"C2\").WithLocation(12, 8),\n // (13,5): error CS0610: Field or property cannot be of type 'ArgIterator'\n // System.ArgIterator P7, // 8\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.ArgIterator\").WithArguments(\"System.ArgIterator\").WithLocation(13, 5),\n // (14,5): error CS0610: Field or property cannot be of type 'TypedReference'\n // System.TypedReference P8, // 9\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.TypedReference\").WithArguments(\"System.TypedReference\").WithLocation(14, 5),\n // (15,5): error CS8345: Field or auto-implemented property cannot be of type 'RefLike' unless it is an instance member of a ref struct.\n // RefLike P9); // 10\n Diagnostic(ErrorCode.ERR_FieldAutoPropCantBeByRefLike, \"RefLike\").WithArguments(\"RefLike\").WithLocation(15, 5)\n );\n }\n\n [ConditionalFact(typeof(DesktopOnly), Reason = ConditionalSkipReason.RestrictedTypesNeedDesktop)]\n [WorkItem(48115, \"https://github.com/dotnet/roslyn/issues/48115\")]\n public void RestrictedTypesAndPointerTypes_NominalMembers()\n {\n var src = @\"\npublic class C { }\npublic static class C2 { }\npublic ref struct RefLike{}\n\npublic unsafe record struct C\n{\n public int* f1; // 1\n public int*[] f2; // 2\n public C f3;\n public delegate* f4; // 3\n public void f5; // 4\n public C2 f6; // 5\n public System.ArgIterator f7; // 6\n public System.TypedReference f8; // 7\n public RefLike f9; // 8\n}\n\";\n\n var comp = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.UnsafeDebugDll);\n comp.VerifyEmitDiagnostics(\n // (8,17): error CS8908: The type 'int*' may not be used for a field of a record.\n // public int* f1; // 1\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"f1\").WithArguments(\"int*\").WithLocation(8, 17),\n // (9,19): error CS8908: The type 'int*[]' may not be used for a field of a record.\n // public int*[] f2; // 2\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"f2\").WithArguments(\"int*[]\").WithLocation(9, 19),\n // (11,32): error CS8908: The type 'delegate*' may not be used for a field of a record.\n // public delegate* f4; // 3\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"f4\").WithArguments(\"delegate*\").WithLocation(11, 32),\n // (12,12): error CS0670: Field cannot have void type\n // public void f5; // 4\n Diagnostic(ErrorCode.ERR_FieldCantHaveVoidType, \"void\").WithLocation(12, 12),\n // (13,15): error CS0723: Cannot declare a variable of static type 'C2'\n // public C2 f6; // 5\n Diagnostic(ErrorCode.ERR_VarDeclIsStaticClass, \"f6\").WithArguments(\"C2\").WithLocation(13, 15),\n // (14,12): error CS0610: Field or property cannot be of type 'ArgIterator'\n // public System.ArgIterator f7; // 6\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.ArgIterator\").WithArguments(\"System.ArgIterator\").WithLocation(14, 12),\n // (15,12): error CS0610: Field or property cannot be of type 'TypedReference'\n // public System.TypedReference f8; // 7\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.TypedReference\").WithArguments(\"System.TypedReference\").WithLocation(15, 12),\n // (16,12): error CS8345: Field or auto-implemented property cannot be of type 'RefLike' unless it is an instance member of a ref struct.\n // public RefLike f9; // 8\n Diagnostic(ErrorCode.ERR_FieldAutoPropCantBeByRefLike, \"RefLike\").WithArguments(\"RefLike\").WithLocation(16, 12)\n );\n }\n\n [ConditionalFact(typeof(DesktopOnly), Reason = ConditionalSkipReason.RestrictedTypesNeedDesktop)]\n [WorkItem(48115, \"https://github.com/dotnet/roslyn/issues/48115\")]\n public void RestrictedTypesAndPointerTypes_NominalMembers_AutoProperties()\n {\n var src = @\"\npublic class C { }\npublic static class C2 { }\npublic ref struct RefLike{}\n\npublic unsafe record struct C\n{\n public int* f1 { get; set; } // 1\n public int*[] f2 { get; set; } // 2\n public C f3 { get; set; }\n public delegate* f4 { get; set; } // 3\n public void f5 { get; set; } // 4\n public C2 f6 { get; set; } // 5, 6\n public System.ArgIterator f7 { get; set; } // 6\n public System.TypedReference f8 { get; set; } // 7\n public RefLike f9 { get; set; } // 8\n}\n\";\n\n var comp = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.UnsafeDebugDll);\n comp.VerifyEmitDiagnostics(\n // (8,17): error CS8908: The type 'int*' may not be used for a field of a record.\n // public int* f1 { get; set; } // 1\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"f1\").WithArguments(\"int*\").WithLocation(8, 17),\n // (9,19): error CS8908: The type 'int*[]' may not be used for a field of a record.\n // public int*[] f2 { get; set; } // 2\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"f2\").WithArguments(\"int*[]\").WithLocation(9, 19),\n // (11,32): error CS8908: The type 'delegate*' may not be used for a field of a record.\n // public delegate* f4 { get; set; } // 3\n Diagnostic(ErrorCode.ERR_BadFieldTypeInRecord, \"f4\").WithArguments(\"delegate*\").WithLocation(11, 32),\n // (12,17): error CS0547: 'C.f5': property or indexer cannot have void type\n // public void f5 { get; set; } // 4\n Diagnostic(ErrorCode.ERR_PropertyCantHaveVoidType, \"f5\").WithArguments(\"C.f5\").WithLocation(12, 17),\n // (13,20): error CS0722: 'C2': static types cannot be used as return types\n // public C2 f6 { get; set; } // 5, 6\n Diagnostic(ErrorCode.ERR_ReturnTypeIsStaticClass, \"get\").WithArguments(\"C2\").WithLocation(13, 20),\n // (13,25): error CS0721: 'C2': static types cannot be used as parameters\n // public C2 f6 { get; set; } // 5, 6\n Diagnostic(ErrorCode.ERR_ParameterIsStaticClass, \"set\").WithArguments(\"C2\").WithLocation(13, 25),\n // (14,12): error CS0610: Field or property cannot be of type 'ArgIterator'\n // public System.ArgIterator f7 { get; set; } // 6\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.ArgIterator\").WithArguments(\"System.ArgIterator\").WithLocation(14, 12),\n // (15,12): error CS0610: Field or property cannot be of type 'TypedReference'\n // public System.TypedReference f8 { get; set; } // 7\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.TypedReference\").WithArguments(\"System.TypedReference\").WithLocation(15, 12),\n // (16,12): error CS8345: Field or auto-implemented property cannot be of type 'RefLike' unless it is an instance member of a ref struct.\n // public RefLike f9 { get; set; } // 8\n Diagnostic(ErrorCode.ERR_FieldAutoPropCantBeByRefLike, \"RefLike\").WithArguments(\"RefLike\").WithLocation(16, 12)\n );\n }\n\n [Fact]\n [WorkItem(48115, \"https://github.com/dotnet/roslyn/issues/48115\")]\n public void RestrictedTypesAndPointerTypes_PointerTypeAllowedForParameterAndProperty()\n {\n var src = @\"\nclass C { }\n\nunsafe record struct C(int* P1, int*[] P2, C P3)\n{\n int* P1\n {\n get { System.Console.Write(\"\"P1 \"\"); return null; }\n init { }\n }\n int*[] P2\n {\n get { System.Console.Write(\"\"P2 \"\"); return null; }\n init { }\n }\n C P3\n {\n get { System.Console.Write(\"\"P3 \"\"); return null; }\n init { }\n }\n\n public unsafe static void Main()\n {\n var x = new C(null, null, null);\n var (x1, x2, x3) = x;\n System.Console.Write(\"\"RAN\"\");\n }\n}\n\";\n var comp = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.UnsafeDebugExe);\n comp.VerifyEmitDiagnostics(\n // (4,29): warning CS8907: Parameter 'P1' is unread. Did you forget to use it to initialize the property with that name?\n // unsafe record struct C(int* P1, int*[] P2, C P3)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"P1\").WithArguments(\"P1\").WithLocation(4, 29),\n // (4,40): warning CS8907: Parameter 'P2' is unread. Did you forget to use it to initialize the property with that name?\n // unsafe record struct C(int* P1, int*[] P2, C P3)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"P2\").WithArguments(\"P2\").WithLocation(4, 40),\n // (4,54): warning CS8907: Parameter 'P3' is unread. Did you forget to use it to initialize the property with that name?\n // unsafe record struct C(int* P1, int*[] P2, C P3)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"P3\").WithArguments(\"P3\").WithLocation(4, 54)\n );\n\n CompileAndVerify(comp, expectedOutput: \"P1 P2 P3 RAN\", verify: Verification.Skipped /* pointers */);\n }\n\n [ConditionalFact(typeof(DesktopOnly), Reason = ConditionalSkipReason.RestrictedTypesNeedDesktop)]\n [WorkItem(48115, \"https://github.com/dotnet/roslyn/issues/48115\")]\n public void RestrictedTypesAndPointerTypes_StaticFields()\n {\n var src = @\"\npublic class C { }\npublic static class C2 { }\npublic ref struct RefLike{}\n\npublic unsafe record C\n{\n public static int* f1;\n public static int*[] f2;\n public static C f3;\n public static delegate* f4;\n public static C2 f6; // 1\n public static System.ArgIterator f7; // 2\n public static System.TypedReference f8; // 3\n public static RefLike f9; // 4\n}\n\";\n\n var comp = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, options: TestOptions.UnsafeDebugDll);\n comp.VerifyEmitDiagnostics(\n // (12,22): error CS0723: Cannot declare a variable of static type 'C2'\n // public static C2 f6; // 1\n Diagnostic(ErrorCode.ERR_VarDeclIsStaticClass, \"f6\").WithArguments(\"C2\").WithLocation(12, 22),\n // (13,19): error CS0610: Field or property cannot be of type 'ArgIterator'\n // public static System.ArgIterator f7; // 2\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.ArgIterator\").WithArguments(\"System.ArgIterator\").WithLocation(13, 19),\n // (14,19): error CS0610: Field or property cannot be of type 'TypedReference'\n // public static System.TypedReference f8; // 3\n Diagnostic(ErrorCode.ERR_FieldCantBeRefAny, \"System.TypedReference\").WithArguments(\"System.TypedReference\").WithLocation(14, 19),\n // (15,19): error CS8345: Field or auto-implemented property cannot be of type 'RefLike' unless it is an instance member of a ref struct.\n // public static RefLike f9; // 4\n Diagnostic(ErrorCode.ERR_FieldAutoPropCantBeByRefLike, \"RefLike\").WithArguments(\"RefLike\").WithLocation(15, 19)\n );\n }\n\n [Fact]\n public void RecordProperties_01()\n {\n var src = @\"\nusing System;\nrecord struct C(int X, int Y)\n{\n int Z = 345;\n public static void Main()\n {\n var c = new C(1, 2);\n Console.Write(c.X);\n Console.Write(c.Y);\n Console.Write(c.Z);\n }\n}\";\n var verifier = CompileAndVerify(src, expectedOutput: @\"12345\").VerifyDiagnostics();\n\n verifier.VerifyIL(\"C..ctor(int, int)\", @\"\n{\n // Code size 26 (0x1a)\n .maxstack 2\n IL_0000: ldarg.0\n IL_0001: ldarg.1\n IL_0002: stfld \"\"int C.k__BackingField\"\"\n IL_0007: ldarg.0\n IL_0008: ldarg.2\n IL_0009: stfld \"\"int C.k__BackingField\"\"\n IL_000e: ldarg.0\n IL_000f: ldc.i4 0x159\n IL_0014: stfld \"\"int C.Z\"\"\n IL_0019: ret\n}\n\");\n\n var c = verifier.Compilation.GlobalNamespace.GetTypeMember(\"C\");\n Assert.False(c.IsReadOnly);\n var x = (IPropertySymbol)c.GetMember(\"X\");\n Assert.Equal(\"readonly System.Int32 C.X.get\", x.GetMethod.ToTestDisplayString());\n Assert.Equal(\"void C.X.set\", x.SetMethod.ToTestDisplayString());\n Assert.False(x.SetMethod!.IsInitOnly);\n\n var xBackingField = (IFieldSymbol)c.GetMember(\"k__BackingField\");\n Assert.Equal(\"System.Int32 C.k__BackingField\", xBackingField.ToTestDisplayString());\n Assert.False(xBackingField.IsReadOnly);\n }\n\n [Fact]\n public void RecordProperties_01_EmptyParameterList()\n {\n var src = @\"\nusing System;\nrecord struct C()\n{\n int Z = 345;\n public static void Main()\n {\n var c = new C();\n Console.Write(c.Z);\n }\n}\";\n CreateCompilation(src).VerifyEmitDiagnostics();\n }\n\n [Fact]\n public void RecordProperties_01_Readonly()\n {\n var src = @\"\nusing System;\nreadonly record struct C(int X, int Y)\n{\n readonly int Z = 345;\n public static void Main()\n {\n var c = new C(1, 2);\n Console.Write(c.X);\n Console.Write(c.Y);\n Console.Write(c.Z);\n }\n}\";\n var verifier = CompileAndVerify(src, expectedOutput: @\"12345\").VerifyDiagnostics();\n\n var c = verifier.Compilation.GlobalNamespace.GetTypeMember(\"C\");\n Assert.True(c.IsReadOnly);\n var x = (IPropertySymbol)c.GetMember(\"X\");\n Assert.Equal(\"System.Int32 C.X.get\", x.GetMethod.ToTestDisplayString());\n Assert.Equal(\"void modreq(System.Runtime.CompilerServices.IsExternalInit) C.X.init\", x.SetMethod.ToTestDisplayString());\n Assert.True(x.SetMethod!.IsInitOnly);\n\n var xBackingField = (IFieldSymbol)c.GetMember(\"k__BackingField\");\n Assert.Equal(\"System.Int32 C.k__BackingField\", xBackingField.ToTestDisplayString());\n Assert.True(xBackingField.IsReadOnly);\n }\n\n [Fact]\n public void RecordProperties_01_ReadonlyMismatch()\n {\n var src = @\"\nreadonly record struct C(int X)\n{\n public int X { get; set; } = X; // 1\n}\nrecord struct C2(int X)\n{\n public int X { get; init; } = X;\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics(\n // (4,16): error CS8341: Auto-implemented instance properties in readonly structs must be readonly.\n // public int X { get; set; } = X; // 1\n Diagnostic(ErrorCode.ERR_AutoPropsInRoStruct, \"X\").WithLocation(4, 16)\n );\n }\n\n [Fact]\n public void RecordProperties_02()\n {\n var src = @\"\nusing System;\nrecord struct C(int X, int Y)\n{\n public C(int a, int b)\n {\n }\n\n public static void Main()\n {\n var c = new C(1, 2);\n Console.WriteLine(c.X);\n Console.WriteLine(c.Y);\n }\n\n private int X1 = X;\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (5,12): error CS0111: Type 'C' already defines a member called 'C' with the same parameter types\n // public C(int a, int b)\n Diagnostic(ErrorCode.ERR_MemberAlreadyExists, \"C\").WithArguments(\"C\", \"C\").WithLocation(5, 12),\n // (5,12): error CS8862: A constructor declared in a record with parameter list must have 'this' constructor initializer.\n // public C(int a, int b)\n Diagnostic(ErrorCode.ERR_UnexpectedOrMissingConstructorInitializerInRecord, \"C\").WithLocation(5, 12),\n // (11,21): error CS0121: The call is ambiguous between the following methods or properties: 'C.C(int, int)' and 'C.C(int, int)'\n // var c = new C(1, 2);\n Diagnostic(ErrorCode.ERR_AmbigCall, \"C\").WithArguments(\"C.C(int, int)\", \"C.C(int, int)\").WithLocation(11, 21)\n );\n }\n\n [Fact]\n public void RecordProperties_03()\n {\n var src = @\"\nusing System;\nrecord struct C(int X, int Y)\n{\n public int X { get; }\n\n public static void Main()\n {\n var c = new C(1, 2);\n Console.WriteLine(c.X);\n Console.WriteLine(c.Y);\n }\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics(\n // (3,15): error CS0843: Auto-implemented property 'C.X' must be fully assigned before control is returned to the caller.\n // record struct C(int X, int Y)\n Diagnostic(ErrorCode.ERR_UnassignedThisAutoProperty, \"C\").WithArguments(\"C.X\").WithLocation(3, 15),\n // (3,21): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(int X, int Y)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(3, 21)\n );\n }\n\n [Fact]\n public void RecordProperties_03_InitializedWithY()\n {\n var src = @\"\nusing System;\nrecord struct C(int X, int Y)\n{\n public int X { get; } = Y;\n\n public static void Main()\n {\n var c = new C(1, 2);\n Console.Write(c.X);\n Console.Write(c.Y);\n }\n}\";\n CompileAndVerify(src, expectedOutput: \"22\")\n .VerifyDiagnostics(\n // (3,21): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(int X, int Y)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(3, 21)\n );\n }\n\n [Fact]\n public void RecordProperties_04()\n {\n var src = @\"\nusing System;\nrecord struct C(int X, int Y)\n{\n public int X { get; } = 3;\n\n public static void Main()\n {\n var c = new C(1, 2);\n Console.Write(c.X);\n Console.Write(c.Y);\n }\n}\";\n CompileAndVerify(src, expectedOutput: \"32\")\n .VerifyDiagnostics(\n // (3,21): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(int X, int Y)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(3, 21)\n );\n }\n\n [Fact]\n public void RecordProperties_05()\n {\n var src = @\"\nrecord struct C(int X, int X)\n{\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,28): error CS0100: The parameter name 'X' is a duplicate\n // record struct C(int X, int X)\n Diagnostic(ErrorCode.ERR_DuplicateParamName, \"X\").WithArguments(\"X\").WithLocation(2, 28),\n // (2,28): error CS0102: The type 'C' already contains a definition for 'X'\n // record struct C(int X, int X)\n Diagnostic(ErrorCode.ERR_DuplicateNameInClass, \"X\").WithArguments(\"C\", \"X\").WithLocation(2, 28)\n );\n\n var expectedMembers = new[]\n {\n \"System.Int32 C.X { get; set; }\",\n \"System.Int32 C.X { get; set; }\"\n };\n AssertEx.Equal(expectedMembers,\n comp.GetMember(\"C\").GetMembers().OfType().ToTestDisplayStrings());\n\n var expectedMemberNames = new[] {\n \".ctor\",\n \"k__BackingField\",\n \"get_X\",\n \"set_X\",\n \"X\",\n \"k__BackingField\",\n \"get_X\",\n \"set_X\",\n \"X\",\n \"ToString\",\n \"PrintMembers\",\n \"op_Inequality\",\n \"op_Equality\",\n \"GetHashCode\",\n \"Equals\",\n \"Equals\",\n \"Deconstruct\",\n \".ctor\"\n };\n AssertEx.Equal(expectedMemberNames, comp.GetMember(\"C\").GetPublicSymbol().MemberNames);\n }\n\n [Fact]\n public void RecordProperties_06()\n {\n var src = @\"\nrecord struct C(int X, int Y)\n{\n public void get_X() { }\n public void set_X() { }\n int get_Y(int value) => value;\n int set_Y(int value) => value;\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,21): error CS0082: Type 'C' already reserves a member called 'get_X' with the same parameter types\n // record struct C(int X, int Y)\n Diagnostic(ErrorCode.ERR_MemberReserved, \"X\").WithArguments(\"get_X\", \"C\").WithLocation(2, 21),\n // (2,28): error CS0082: Type 'C' already reserves a member called 'set_Y' with the same parameter types\n // record struct C(int X, int Y)\n Diagnostic(ErrorCode.ERR_MemberReserved, \"Y\").WithArguments(\"set_Y\", \"C\").WithLocation(2, 28)\n );\n\n var actualMembers = comp.GetMember(\"C\").GetMembers().ToTestDisplayStrings();\n var expectedMembers = new[]\n {\n \"C..ctor(System.Int32 X, System.Int32 Y)\",\n \"System.Int32 C.k__BackingField\",\n \"readonly System.Int32 C.X.get\",\n \"void C.X.set\",\n \"System.Int32 C.X { get; set; }\",\n \"System.Int32 C.k__BackingField\",\n \"readonly System.Int32 C.Y.get\",\n \"void C.Y.set\",\n \"System.Int32 C.Y { get; set; }\",\n \"void C.get_X()\",\n \"void C.set_X()\",\n \"System.Int32 C.get_Y(System.Int32 value)\",\n \"System.Int32 C.set_Y(System.Int32 value)\",\n \"readonly System.String C.ToString()\",\n \"readonly System.Boolean C.PrintMembers(System.Text.StringBuilder builder)\",\n \"System.Boolean C.op_Inequality(C left, C right)\",\n \"System.Boolean C.op_Equality(C left, C right)\",\n \"readonly System.Int32 C.GetHashCode()\",\n \"readonly System.Boolean C.Equals(System.Object obj)\",\n \"readonly System.Boolean C.Equals(C other)\",\n \"readonly void C.Deconstruct(out System.Int32 X, out System.Int32 Y)\",\n \"C..ctor()\",\n };\n AssertEx.Equal(expectedMembers, actualMembers);\n }\n\n [Fact]\n public void RecordProperties_07()\n {\n var comp = CreateCompilation(@\"\nrecord struct C1(object P, object get_P);\nrecord struct C2(object get_P, object P);\");\n comp.VerifyDiagnostics(\n // (2,25): error CS0102: The type 'C1' already contains a definition for 'get_P'\n // record struct C1(object P, object get_P);\n Diagnostic(ErrorCode.ERR_DuplicateNameInClass, \"P\").WithArguments(\"C1\", \"get_P\").WithLocation(2, 25),\n // (3,39): error CS0102: The type 'C2' already contains a definition for 'get_P'\n // record struct C2(object get_P, object P);\n Diagnostic(ErrorCode.ERR_DuplicateNameInClass, \"P\").WithArguments(\"C2\", \"get_P\").WithLocation(3, 39)\n );\n }\n\n [Fact]\n public void RecordProperties_08()\n {\n var comp = CreateCompilation(@\"\nrecord struct C1(object O1)\n{\n public object O1 { get; } = O1;\n public object O2 { get; } = O1;\n}\");\n comp.VerifyDiagnostics();\n }\n\n [Fact]\n public void RecordProperties_09()\n {\n var src = @\"\nrecord struct C(object P1, object P2, object P3, object P4)\n{\n class P1 { }\n object P2 = 2;\n int P3(object o) => 3;\n int P4(T t) => 4;\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,24): error CS0102: The type 'C' already contains a definition for 'P1'\n // record struct C(object P1, object P2, object P3, object P4)\n Diagnostic(ErrorCode.ERR_DuplicateNameInClass, \"P1\").WithArguments(\"C\", \"P1\").WithLocation(2, 24),\n // (2,35): warning CS8907: Parameter 'P2' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(object P1, object P2, object P3, object P4)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"P2\").WithArguments(\"P2\").WithLocation(2, 35),\n // (6,9): error CS0102: The type 'C' already contains a definition for 'P3'\n // int P3(object o) => 3;\n Diagnostic(ErrorCode.ERR_DuplicateNameInClass, \"P3\").WithArguments(\"C\", \"P3\").WithLocation(6, 9),\n // (7,9): error CS0102: The type 'C' already contains a definition for 'P4'\n // int P4(T t) => 4;\n Diagnostic(ErrorCode.ERR_DuplicateNameInClass, \"P4\").WithArguments(\"C\", \"P4\").WithLocation(7, 9)\n );\n }\n\n [Fact]\n public void RecordProperties_10()\n {\n var src = @\"\nrecord struct C(object P)\n{\n const int P = 4;\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,24): error CS8866: Record member 'C.P' must be a readable instance property or field of type 'object' to match positional parameter 'P'.\n // record struct C(object P)\n Diagnostic(ErrorCode.ERR_BadRecordMemberForPositionalParameter, \"P\").WithArguments(\"C.P\", \"object\", \"P\").WithLocation(2, 24),\n // (2,24): warning CS8907: Parameter 'P' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(object P)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"P\").WithArguments(\"P\").WithLocation(2, 24)\n );\n }\n\n [Fact]\n public void RecordProperties_11_UnreadPositionalParameter()\n {\n var comp = CreateCompilation(@\"\nrecord struct C1(object O1, object O2, object O3) // 1, 2\n{\n public object O1 { get; init; }\n public object O2 { get; init; } = M(O2);\n public object O3 { get; init; } = M(O3 = null);\n private static object M(object o) => o;\n}\n\");\n comp.VerifyDiagnostics(\n // (2,15): error CS0843: Auto-implemented property 'C1.O1' must be fully assigned before control is returned to the caller.\n // record struct C1(object O1, object O2, object O3) // 1, 2\n Diagnostic(ErrorCode.ERR_UnassignedThisAutoProperty, \"C1\").WithArguments(\"C1.O1\").WithLocation(2, 15),\n // (2,25): warning CS8907: Parameter 'O1' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C1(object O1, object O2, object O3) // 1, 2\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"O1\").WithArguments(\"O1\").WithLocation(2, 25),\n // (2,47): warning CS8907: Parameter 'O3' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C1(object O1, object O2, object O3) // 1, 2\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"O3\").WithArguments(\"O3\").WithLocation(2, 47)\n );\n }\n\n [Fact]\n public void RecordProperties_11_UnreadPositionalParameter_InRefOut()\n {\n var comp = CreateCompilation(@\"\nrecord struct C1(object O1, object O2, object O3) // 1\n{\n public object O1 { get; init; } = MIn(in O1);\n public object O2 { get; init; } = MRef(ref O2);\n public object O3 { get; init; } = MOut(out O3);\n\n static object MIn(in object o) => o;\n static object MRef(ref object o) => o;\n static object MOut(out object o) => throw null;\n}\n\");\n comp.VerifyDiagnostics(\n // (2,47): warning CS8907: Parameter 'O3' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C1(object O1, object O2, object O3) // 1\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"O3\").WithArguments(\"O3\").WithLocation(2, 47)\n );\n }\n\n [Fact]\n public void RecordProperties_SelfContainedStruct()\n {\n var comp = CreateCompilation(@\"\nrecord struct C(C c);\n\");\n comp.VerifyDiagnostics(\n // (2,19): error CS0523: Struct member 'C.c' of type 'C' causes a cycle in the struct layout\n // record struct C(C c);\n Diagnostic(ErrorCode.ERR_StructLayoutCycle, \"c\").WithArguments(\"C.c\", \"C\").WithLocation(2, 19)\n );\n }\n\n [Fact]\n public void RecordProperties_PropertyInValueType()\n {\n var corlib_cs = @\"\nnamespace System\n{\n public class Object\n {\n public virtual bool Equals(object x) => throw null;\n public virtual int GetHashCode() => throw null;\n public virtual string ToString() => throw null;\n }\n public class Exception { }\n public class ValueType\n {\n public bool X { get; set; }\n }\n public class Attribute { }\n public class String { }\n public struct Void { }\n public struct Boolean { }\n public struct Char { }\n public struct Int32 { }\n public interface IEquatable { }\n}\nnamespace System.Collections.Generic\n{\n public abstract class EqualityComparer\n {\n public static EqualityComparer Default => throw null;\n public abstract int GetHashCode(T t);\n }\n}\nnamespace System.Text\n{\n public class StringBuilder\n {\n public StringBuilder Append(string s) => null;\n public StringBuilder Append(char c) => null;\n public StringBuilder Append(object o) => null;\n }\n}\n\";\n var corlibRef = CreateEmptyCompilation(corlib_cs).EmitToImageReference();\n\n {\n var src = @\"\nrecord struct C(bool X)\n{\n bool M()\n {\n return X;\n }\n}\n\";\n var comp = CreateEmptyCompilation(src, parseOptions: TestOptions.RegularPreview, references: new[] { corlibRef });\n comp.VerifyEmitDiagnostics(\n // (2,22): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(bool X)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(2, 22)\n );\n\n Assert.Null(comp.GlobalNamespace.GetTypeMember(\"C\").GetMember(\"X\"));\n var tree = comp.SyntaxTrees.Single();\n var model = comp.GetSemanticModel(tree, ignoreAccessibility: false);\n var x = tree.GetRoot().DescendantNodes().OfType().Single().Expression;\n Assert.Equal(\"System.Boolean System.ValueType.X { get; set; }\", model.GetSymbolInfo(x!).Symbol.ToTestDisplayString());\n }\n\n {\n var src = @\"\nreadonly record struct C(bool X)\n{\n bool M()\n {\n return X;\n }\n}\n\";\n var comp = CreateEmptyCompilation(src, parseOptions: TestOptions.RegularPreview, references: new[] { corlibRef });\n comp.VerifyEmitDiagnostics(\n // (2,31): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // readonly record struct C(bool X)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(2, 31)\n );\n\n Assert.Null(comp.GlobalNamespace.GetTypeMember(\"C\").GetMember(\"X\"));\n var tree = comp.SyntaxTrees.Single();\n var model = comp.GetSemanticModel(tree, ignoreAccessibility: false);\n var x = tree.GetRoot().DescendantNodes().OfType().Single().Expression;\n Assert.Equal(\"System.Boolean System.ValueType.X { get; set; }\", model.GetSymbolInfo(x!).Symbol.ToTestDisplayString());\n }\n }\n\n [Fact]\n public void RecordProperties_PropertyInValueType_Static()\n {\n var corlib_cs = @\"\nnamespace System\n{\n public class Object\n {\n public virtual bool Equals(object x) => throw null;\n public virtual int GetHashCode() => throw null;\n public virtual string ToString() => throw null;\n }\n public class Exception { }\n public class ValueType\n {\n public static bool X { get; set; }\n }\n public class Attribute { }\n public class String { }\n public struct Void { }\n public struct Boolean { }\n public struct Char { }\n public struct Int32 { }\n public interface IEquatable { }\n}\nnamespace System.Collections.Generic\n{\n public abstract class EqualityComparer\n {\n public static EqualityComparer Default => throw null;\n public abstract int GetHashCode(T t);\n }\n}\nnamespace System.Text\n{\n public class StringBuilder\n {\n public StringBuilder Append(string s) => null;\n public StringBuilder Append(char c) => null;\n public StringBuilder Append(object o) => null;\n }\n}\n\";\n var corlibRef = CreateEmptyCompilation(corlib_cs).EmitToImageReference();\n var src = @\"\nrecord struct C(bool X)\n{\n bool M()\n {\n return X;\n }\n}\n\";\n var comp = CreateEmptyCompilation(src, parseOptions: TestOptions.RegularPreview, references: new[] { corlibRef });\n comp.VerifyEmitDiagnostics(\n // (2,22): error CS8866: Record member 'System.ValueType.X' must be a readable instance property or field of type 'bool' to match positional parameter 'X'.\n // record struct C(bool X)\n Diagnostic(ErrorCode.ERR_BadRecordMemberForPositionalParameter, \"X\").WithArguments(\"System.ValueType.X\", \"bool\", \"X\").WithLocation(2, 22),\n // (2,22): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(bool X)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(2, 22)\n );\n }\n\n [Fact]\n public void StaticCtor()\n {\n var src = @\"\nrecord R(int x)\n{\n static void Main() { }\n\n static R()\n {\n System.Console.Write(\"\"static ctor\"\");\n }\n}\n\";\n\n var comp = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.DebugExe);\n comp.VerifyEmitDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"static ctor\", verify: Verification.Skipped /* init-only */);\n }\n\n [Fact]\n public void StaticCtor_ParameterlessPrimaryCtor()\n {\n var src = @\"\nrecord struct R(int I)\n{\n static R() { }\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics();\n }\n\n [Fact]\n public void StaticCtor_CopyCtor()\n {\n var src = @\"\nrecord struct R(int I)\n{\n static R(R r) { }\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics(\n // (4,12): error CS0132: 'R.R(R)': a static constructor must be parameterless\n // static R(R r) { }\n Diagnostic(ErrorCode.ERR_StaticConstParam, \"R\").WithArguments(\"R.R(R)\").WithLocation(4, 12)\n );\n }\n\n [Fact]\n public void InterfaceImplementation_NotReadonly()\n {\n var source = @\"\nI r = new R(42);\nr.P2 = 43;\nr.P3 = 44;\nSystem.Console.Write((r.P1, r.P2, r.P3));\n\ninterface I\n{\n int P1 { get; set; }\n int P2 { get; set; }\n int P3 { get; set; }\n}\nrecord struct R(int P1) : I\n{\n public int P2 { get; set; } = 0;\n int I.P3 { get; set; } = 0;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"(42, 43, 44)\");\n }\n\n [Fact]\n public void InterfaceImplementation_NotReadonly_InitOnlyInterface()\n {\n var source = @\"\ninterface I\n{\n int P1 { get; init; }\n}\nrecord struct R(int P1) : I;\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (6,27): error CS8854: 'R' does not implement interface member 'I.P1.init'. 'R.P1.set' cannot implement 'I.P1.init'.\n // record struct R(int P1) : I;\n Diagnostic(ErrorCode.ERR_CloseUnimplementedInterfaceMemberWrongInitOnly, \"I\").WithArguments(\"R\", \"I.P1.init\", \"R.P1.set\").WithLocation(6, 27)\n );\n }\n\n [Fact]\n public void InterfaceImplementation_Readonly()\n {\n var source = @\"\nI r = new R(42) { P2 = 43 };\nSystem.Console.Write((r.P1, r.P2));\n\ninterface I\n{\n int P1 { get; init; }\n int P2 { get; init; }\n}\nreadonly record struct R(int P1) : I\n{\n public int P2 { get; init; } = 0;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"(42, 43)\", verify: Verification.Skipped /* init-only */);\n }\n\n [Fact]\n public void InterfaceImplementation_Readonly_SetInterface()\n {\n var source = @\"\ninterface I\n{\n int P1 { get; set; }\n}\nreadonly record struct R(int P1) : I;\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (6,36): error CS8854: 'R' does not implement interface member 'I.P1.set'. 'R.P1.init' cannot implement 'I.P1.set'.\n // readonly record struct R(int P1) : I;\n Diagnostic(ErrorCode.ERR_CloseUnimplementedInterfaceMemberWrongInitOnly, \"I\").WithArguments(\"R\", \"I.P1.set\", \"R.P1.init\").WithLocation(6, 36)\n );\n }\n\n [Fact]\n public void InterfaceImplementation_Readonly_PrivateImplementation()\n {\n var source = @\"\nI r = new R(42) { P2 = 43, P3 = 44 };\nSystem.Console.Write((r.P1, r.P2, r.P3));\n\ninterface I\n{\n int P1 { get; init; }\n int P2 { get; init; }\n int P3 { get; init; }\n}\nreadonly record struct R(int P1) : I\n{\n public int P2 { get; init; } = 0;\n int I.P3 { get; init; } = 0; // not practically initializable\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (2,28): error CS0117: 'R' does not contain a definition for 'P3'\n // I r = new R(42) { P2 = 43, P3 = 44 };\n Diagnostic(ErrorCode.ERR_NoSuchMember, \"P3\").WithArguments(\"R\", \"P3\").WithLocation(2, 28)\n );\n }\n\n [Fact]\n public void Initializers_01()\n {\n var src = @\"\nusing System;\n\nrecord struct C(int X)\n{\n int Z = X + 1;\n\n public static void Main()\n {\n var c = new C(1);\n Console.WriteLine(c.Z);\n }\n}\";\n var verifier = CompileAndVerify(src, expectedOutput: @\"2\").VerifyDiagnostics();\n\n var comp = CreateCompilation(src);\n\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree);\n\n var x = tree.GetRoot().DescendantNodes().OfType().Where(id => id.Identifier.ValueText == \"X\").First();\n Assert.Equal(\"= X + 1\", x.Parent!.Parent!.ToString());\n\n var symbol = model.GetSymbolInfo(x).Symbol;\n Assert.Equal(SymbolKind.Parameter, symbol!.Kind);\n Assert.Equal(\"System.Int32 X\", symbol.ToTestDisplayString());\n Assert.Equal(\"C..ctor(System.Int32 X)\", symbol.ContainingSymbol.ToTestDisplayString());\n Assert.Equal(\"System.Int32 C.Z\", model.GetEnclosingSymbol(x.SpanStart).ToTestDisplayString());\n Assert.Contains(symbol, model.LookupSymbols(x.SpanStart, name: \"X\"));\n Assert.Contains(\"X\", model.LookupNames(x.SpanStart));\n\n var recordDeclaration = tree.GetRoot().DescendantNodes().OfType().Single();\n Assert.Equal(\"C\", recordDeclaration.Identifier.ValueText);\n Assert.Null(model.GetOperation(recordDeclaration));\n }\n\n [Fact]\n public void Initializers_02()\n {\n var src = @\"\nrecord struct C(int X)\n{\n static int Z = X + 1;\n}\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (4,20): error CS0236: A field initializer cannot reference the non-static field, method, or property 'C.X'\n // static int Z = X + 1;\n Diagnostic(ErrorCode.ERR_FieldInitRefNonstatic, \"X\").WithArguments(\"C.X\").WithLocation(4, 20)\n );\n\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree);\n\n var x = tree.GetRoot().DescendantNodes().OfType().Where(id => id.Identifier.ValueText == \"X\").First();\n Assert.Equal(\"= X + 1\", x.Parent!.Parent!.ToString());\n\n var symbol = model.GetSymbolInfo(x).Symbol;\n Assert.Equal(SymbolKind.Property, symbol!.Kind);\n Assert.Equal(\"System.Int32 C.X { get; set; }\", symbol.ToTestDisplayString());\n Assert.Equal(\"C\", symbol.ContainingSymbol.ToTestDisplayString());\n Assert.Equal(\"System.Int32 C.Z\", model.GetEnclosingSymbol(x.SpanStart).ToTestDisplayString());\n Assert.Contains(symbol, model.LookupSymbols(x.SpanStart, name: \"X\"));\n Assert.Contains(\"X\", model.LookupNames(x.SpanStart));\n }\n\n [Fact]\n public void Initializers_03()\n {\n var src = @\"\nrecord struct C(int X)\n{\n const int Z = X + 1;\n}\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (4,19): error CS0236: A field initializer cannot reference the non-static field, method, or property 'C.X'\n // const int Z = X + 1;\n Diagnostic(ErrorCode.ERR_FieldInitRefNonstatic, \"X\").WithArguments(\"C.X\").WithLocation(4, 19)\n );\n\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree);\n\n var x = tree.GetRoot().DescendantNodes().OfType().Where(id => id.Identifier.ValueText == \"X\").First();\n Assert.Equal(\"= X + 1\", x.Parent!.Parent!.ToString());\n\n var symbol = model.GetSymbolInfo(x).Symbol;\n Assert.Equal(SymbolKind.Property, symbol!.Kind);\n Assert.Equal(\"System.Int32 C.X { get; set; }\", symbol.ToTestDisplayString());\n Assert.Equal(\"C\", symbol.ContainingSymbol.ToTestDisplayString());\n Assert.Equal(\"System.Int32 C.Z\", model.GetEnclosingSymbol(x.SpanStart).ToTestDisplayString());\n Assert.Contains(symbol, model.LookupSymbols(x.SpanStart, name: \"X\"));\n Assert.Contains(\"X\", model.LookupNames(x.SpanStart));\n }\n\n [Fact]\n public void Initializers_04()\n {\n var src = @\"\nusing System;\n\nrecord struct C(int X)\n{\n Func Z = () => X + 1;\n\n public static void Main()\n {\n var c = new C(1);\n Console.WriteLine(c.Z());\n }\n}\";\n var verifier = CompileAndVerify(src, expectedOutput: @\"2\").VerifyDiagnostics();\n\n var comp = CreateCompilation(src);\n\n var tree = comp.SyntaxTrees.First();\n var model = comp.GetSemanticModel(tree);\n\n var x = tree.GetRoot().DescendantNodes().OfType().Where(id => id.Identifier.ValueText == \"X\").First();\n Assert.Equal(\"() => X + 1\", x.Parent!.Parent!.ToString());\n\n var symbol = model.GetSymbolInfo(x).Symbol;\n Assert.Equal(SymbolKind.Parameter, symbol!.Kind);\n Assert.Equal(\"System.Int32 X\", symbol.ToTestDisplayString());\n Assert.Equal(\"C..ctor(System.Int32 X)\", symbol.ContainingSymbol.ToTestDisplayString());\n Assert.Equal(\"lambda expression\", model.GetEnclosingSymbol(x.SpanStart).ToTestDisplayString());\n Assert.Contains(symbol, model.LookupSymbols(x.SpanStart, name: \"X\"));\n Assert.Contains(\"X\", model.LookupNames(x.SpanStart));\n }\n\n [Fact]\n public void SynthesizedRecordPointerProperty()\n {\n var src = @\"\nrecord struct R(int P1, int* P2, delegate* P3);\";\n\n var comp = CreateCompilation(src);\n var p = comp.GlobalNamespace.GetTypeMember(\"R\").GetMember(\"P1\");\n Assert.False(p.HasPointerType);\n\n p = comp.GlobalNamespace.GetTypeMember(\"R\").GetMember(\"P2\");\n Assert.True(p.HasPointerType);\n\n p = comp.GlobalNamespace.GetTypeMember(\"R\").GetMember(\"P3\");\n Assert.True(p.HasPointerType);\n }\n\n [Fact]\n public void PositionalMemberModifiers_In()\n {\n var src = @\"\nvar r = new R(42);\nint i = 43;\nvar r2 = new R(in i);\nSystem.Console.Write((r.P1, r2.P1));\n\nrecord struct R(in int P1);\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n var verifier = CompileAndVerify(comp, expectedOutput: \"(42, 43)\");\n\n var actualMembers = comp.GetMember(\"R\").Constructors.ToTestDisplayStrings();\n var expectedMembers = new[]\n {\n \"R..ctor(in System.Int32 P1)\",\n \"R..ctor()\"\n };\n AssertEx.Equal(expectedMembers, actualMembers);\n }\n\n [Fact]\n public void PositionalMemberModifiers_Params()\n {\n var src = @\"\nvar r = new R(42, 43);\nvar r2 = new R(new[] { 44, 45 });\nSystem.Console.Write((r.Array[0], r.Array[1], r2.Array[0], r2.Array[1]));\n\nrecord struct R(params int[] Array);\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"(42, 43, 44, 45)\");\n\n var actualMembers = comp.GetMember(\"R\").Constructors.ToTestDisplayStrings();\n var expectedMembers = new[]\n {\n \"R..ctor(params System.Int32[] Array)\",\n \"R..ctor()\"\n };\n AssertEx.Equal(expectedMembers, actualMembers);\n }\n\n [Fact]\n public void PositionalMemberDefaultValue()\n {\n var src = @\"\nvar r = new R(); // This uses the parameterless constructor\nSystem.Console.Write(r.P);\n\nrecord struct R(int P = 42);\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"0\");\n }\n\n [Fact]\n public void PositionalMemberDefaultValue_PassingOneArgument()\n {\n var src = @\"\nvar r = new R(41);\nSystem.Console.Write(r.O);\nSystem.Console.Write(\"\" \"\");\nSystem.Console.Write(r.P);\n\nrecord struct R(int O, int P = 42);\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"41 42\");\n }\n\n [Fact]\n public void PositionalMemberDefaultValue_AndPropertyWithInitializer()\n {\n var src = @\"\nvar r = new R(0);\nSystem.Console.Write(r.P);\n\nrecord struct R(int O, int P = 1)\n{\n public int P { get; init; } = 42;\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (5,28): warning CS8907: Parameter 'P' is unread. Did you forget to use it to initialize the property with that name?\n // record struct R(int O, int P = 1)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"P\").WithArguments(\"P\").WithLocation(5, 28)\n );\n var verifier = CompileAndVerify(comp, expectedOutput: \"42\", verify: Verification.Skipped /* init-only */);\n\n verifier.VerifyIL(\"R..ctor(int, int)\", @\"\n{\n // Code size 16 (0x10)\n .maxstack 2\n IL_0000: ldarg.0\n IL_0001: ldarg.1\n IL_0002: stfld \"\"int R.k__BackingField\"\"\n IL_0007: ldarg.0\n IL_0008: ldc.i4.s 42\n IL_000a: stfld \"\"int R.k__BackingField\"\"\n IL_000f: ret\n}\");\n }\n\n [Fact]\n public void PositionalMemberDefaultValue_AndPropertyWithoutInitializer()\n {\n var src = @\"\nrecord struct R(int P = 42)\n{\n public int P { get; init; }\n\n public static void Main()\n {\n var r = new R();\n System.Console.Write(r.P);\n }\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,15): error CS0843: Auto-implemented property 'R.P' must be fully assigned before control is returned to the caller.\n // record struct R(int P = 42)\n Diagnostic(ErrorCode.ERR_UnassignedThisAutoProperty, \"R\").WithArguments(\"R.P\").WithLocation(2, 15),\n // (2,21): warning CS8907: Parameter 'P' is unread. Did you forget to use it to initialize the property with that name?\n // record struct R(int P = 42)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"P\").WithArguments(\"P\").WithLocation(2, 21)\n );\n }\n\n [Fact]\n public void PositionalMemberDefaultValue_AndPropertyWithInitializer_CopyingParameter()\n {\n var src = @\"\nvar r = new R(0);\nSystem.Console.Write(r.P);\n\nrecord struct R(int O, int P = 42)\n{\n public int P { get; init; } = P;\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n var verifier = CompileAndVerify(comp, expectedOutput: \"42\", verify: Verification.Skipped /* init-only */);\n\n verifier.VerifyIL(\"R..ctor(int, int)\", @\"\n{\n // Code size 15 (0xf)\n .maxstack 2\n IL_0000: ldarg.0\n IL_0001: ldarg.1\n IL_0002: stfld \"\"int R.k__BackingField\"\"\n IL_0007: ldarg.0\n IL_0008: ldarg.2\n IL_0009: stfld \"\"int R.k__BackingField\"\"\n IL_000e: ret\n}\");\n }\n\n [Fact]\n public void RecordWithConstraints_NullableWarning()\n {\n var src = @\"\n#nullable enable\nvar r = new R(\"\"R\"\");\nvar r2 = new R2(\"\"R2\"\");\nSystem.Console.Write((r.P, r2.P));\n\nrecord struct R(T P) where T : class;\nrecord struct R2(T P) where T : class { }\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (3,15): warning CS8634: The type 'string?' cannot be used as type parameter 'T' in the generic type or method 'R'. Nullability of type argument 'string?' doesn't match 'class' constraint.\n // var r = new R(\"R\");\n Diagnostic(ErrorCode.WRN_NullabilityMismatchInTypeParameterReferenceTypeConstraint, \"string?\").WithArguments(\"R\", \"T\", \"string?\").WithLocation(3, 15),\n // (4,17): warning CS8634: The type 'string?' cannot be used as type parameter 'T' in the generic type or method 'R2'. Nullability of type argument 'string?' doesn't match 'class' constraint.\n // var r2 = new R2(\"R2\");\n Diagnostic(ErrorCode.WRN_NullabilityMismatchInTypeParameterReferenceTypeConstraint, \"string?\").WithArguments(\"R2\", \"T\", \"string?\").WithLocation(4, 17)\n );\n CompileAndVerify(comp, expectedOutput: \"(R, R2)\");\n }\n\n [Fact]\n public void RecordWithConstraints_ConstraintError()\n {\n var src = @\"\nrecord struct R(T P) where T : class;\nrecord struct R2(T P) where T : class { }\n\npublic class C\n{\n public static void Main()\n {\n _ = new R(1);\n _ = new R2(2);\n }\n}\";\n\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (9,19): error CS0452: The type 'int' must be a reference type in order to use it as parameter 'T' in the generic type or method 'R'\n // _ = new R(1);\n Diagnostic(ErrorCode.ERR_RefConstraintNotSatisfied, \"int\").WithArguments(\"R\", \"T\", \"int\").WithLocation(9, 19),\n // (10,20): error CS0452: The type 'int' must be a reference type in order to use it as parameter 'T' in the generic type or method 'R2'\n // _ = new R2(2);\n Diagnostic(ErrorCode.ERR_RefConstraintNotSatisfied, \"int\").WithArguments(\"R2\", \"T\", \"int\").WithLocation(10, 20)\n );\n }\n\n [Fact]\n public void CyclicBases4()\n {\n var text =\n@\"\nrecord struct A : B> { }\nrecord struct B : A>\n{\n A F() { return null; }\n}\n\";\n var comp = CreateCompilation(text);\n comp.GetDeclarationDiagnostics().Verify(\n // (3,22): error CS0527: Type 'A>' in interface list is not an interface\n // record struct B : A>\n Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, \"A>\").WithArguments(\"A>\").WithLocation(3, 22),\n // (2,22): error CS0527: Type 'B>' in interface list is not an interface\n // record struct A : B> { }\n Diagnostic(ErrorCode.ERR_NonInterfaceInInterfaceList, \"B>\").WithArguments(\"B>\").WithLocation(2, 22)\n );\n }\n\n [Fact]\n public void PartialClassWithDifferentTupleNamesInImplementedInterfaces()\n {\n var source = @\"\npublic interface I { }\npublic partial record C1 : I<(int a, int b)> { }\npublic partial record C1 : I<(int notA, int notB)> { }\n\npublic partial record C2 : I<(int a, int b)> { }\npublic partial record C2 : I<(int, int)> { }\n\npublic partial record C3 : I<(int a, int b)> { }\npublic partial record C3 : I<(int a, int b)> { }\n\npublic partial record C4 : I<(int a, int b)> { }\npublic partial record C4 : I<(int b, int a)> { }\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (3,23): error CS8140: 'I<(int notA, int notB)>' is already listed in the interface list on type 'C1' with different tuple element names, as 'I<(int a, int b)>'.\n // public partial record C1 : I<(int a, int b)> { }\n Diagnostic(ErrorCode.ERR_DuplicateInterfaceWithTupleNamesInBaseList, \"C1\").WithArguments(\"I<(int notA, int notB)>\", \"I<(int a, int b)>\", \"C1\").WithLocation(3, 23),\n // (6,23): error CS8140: 'I<(int, int)>' is already listed in the interface list on type 'C2' with different tuple element names, as 'I<(int a, int b)>'.\n // public partial record C2 : I<(int a, int b)> { }\n Diagnostic(ErrorCode.ERR_DuplicateInterfaceWithTupleNamesInBaseList, \"C2\").WithArguments(\"I<(int, int)>\", \"I<(int a, int b)>\", \"C2\").WithLocation(6, 23),\n // (12,23): error CS8140: 'I<(int b, int a)>' is already listed in the interface list on type 'C4' with different tuple element names, as 'I<(int a, int b)>'.\n // public partial record C4 : I<(int a, int b)> { }\n Diagnostic(ErrorCode.ERR_DuplicateInterfaceWithTupleNamesInBaseList, \"C4\").WithArguments(\"I<(int b, int a)>\", \"I<(int a, int b)>\", \"C4\").WithLocation(12, 23)\n );\n }\n\n [Fact]\n public void CS0267ERR_PartialMisplaced()\n {\n var test = @\"\npartial public record struct C // CS0267\n{\n}\n\";\n\n CreateCompilation(test).VerifyDiagnostics(\n // (2,1): error CS0267: The 'partial' modifier can only appear immediately before 'class', 'record', 'struct', 'interface', or a method return type.\n // partial public record struct C // CS0267\n Diagnostic(ErrorCode.ERR_PartialMisplaced, \"partial\").WithLocation(2, 1)\n );\n }\n\n [Fact]\n public void SealedStaticRecord()\n {\n var source = @\"\nsealed static record struct R;\n\";\n CreateCompilation(source).VerifyDiagnostics(\n // (2,29): error CS0106: The modifier 'sealed' is not valid for this item\n // sealed static record struct R;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"R\").WithArguments(\"sealed\").WithLocation(2, 29),\n // (2,29): error CS0106: The modifier 'static' is not valid for this item\n // sealed static record struct R;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"R\").WithArguments(\"static\").WithLocation(2, 29)\n );\n }\n\n [Fact]\n public void CS0513ERR_AbstractInConcreteClass02()\n {\n var text = @\"\nrecord struct C\n{\n public abstract event System.Action E;\n public abstract int this[int x] { get; set; }\n}\n\";\n CreateCompilation(text).VerifyDiagnostics(\n // (5,25): error CS0106: The modifier 'abstract' is not valid for this item\n // public abstract int this[int x] { get; set; }\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"this\").WithArguments(\"abstract\").WithLocation(5, 25),\n // (4,41): error CS0106: The modifier 'abstract' is not valid for this item\n // public abstract event System.Action E;\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"E\").WithArguments(\"abstract\").WithLocation(4, 41)\n );\n }\n\n [Fact]\n public void CS0574ERR_BadDestructorName()\n {\n var test = @\"\npublic record struct iii\n{\n ~iiii(){}\n}\n\";\n\n CreateCompilation(test).VerifyDiagnostics(\n // (4,6): error CS0574: Name of destructor must match name of type\n // ~iiii(){}\n Diagnostic(ErrorCode.ERR_BadDestructorName, \"iiii\").WithLocation(4, 6),\n // (4,6): error CS0575: Only class types can contain destructors\n // ~iiii(){}\n Diagnostic(ErrorCode.ERR_OnlyClassesCanContainDestructors, \"iiii\").WithArguments(\"iii.~iii()\").WithLocation(4, 6)\n );\n }\n\n [Fact]\n public void StaticRecordWithConstructorAndDestructor()\n {\n var text = @\"\nstatic record struct R(int I)\n{\n public R() : this(0) { }\n ~R() { }\n}\n\";\n var comp = CreateCompilation(text);\n comp.VerifyDiagnostics(\n // (2,22): error CS0106: The modifier 'static' is not valid for this item\n // static record struct R(int I)\n Diagnostic(ErrorCode.ERR_BadMemberFlag, \"R\").WithArguments(\"static\").WithLocation(2, 22),\n // (5,6): error CS0575: Only class types can contain destructors\n // ~R() { }\n Diagnostic(ErrorCode.ERR_OnlyClassesCanContainDestructors, \"R\").WithArguments(\"R.~R()\").WithLocation(5, 6)\n );\n }\n\n [Fact]\n public void RecordWithPartialMethodExplicitImplementation()\n {\n var source =\n@\"record struct R\n{\n partial void M();\n}\";\n CreateCompilation(source).VerifyDiagnostics(\n // (3,18): error CS0751: A partial method must be declared within a partial type\n // partial void M();\n Diagnostic(ErrorCode.ERR_PartialMethodOnlyInPartialClass, \"M\").WithLocation(3, 18)\n );\n }\n\n [Fact]\n public void RecordWithPartialMethodRequiringBody()\n {\n var source =\n@\"partial record struct R\n{\n public partial int M();\n}\";\n CreateCompilation(source).VerifyDiagnostics(\n // (3,24): error CS8795: Partial method 'R.M()' must have an implementation part because it has accessibility modifiers.\n // public partial int M();\n Diagnostic(ErrorCode.ERR_PartialMethodWithAccessibilityModsMustHaveImplementation, \"M\").WithArguments(\"R.M()\").WithLocation(3, 24)\n );\n }\n\n [Fact]\n public void CanDeclareIteratorInRecord()\n {\n var source = @\"\nusing System.Collections.Generic;\n\nforeach(var i in new X(42).GetItems())\n{\n System.Console.Write(i);\n}\n\npublic record struct X(int a)\n{\n public IEnumerable GetItems() { yield return a; yield return a + 1; }\n}\";\n\n var comp = CreateCompilation(source).VerifyDiagnostics();\n\n CompileAndVerify(comp, expectedOutput: \"4243\");\n }\n\n [Fact]\n public void ParameterlessConstructor()\n {\n var src = @\"\nSystem.Console.Write(new C().Property);\n\nrecord struct C()\n{\n public int Property { get; set; } = 42;\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"42\");\n }\n\n [Fact]\n public void XmlDoc()\n {\n var src = @\"\n/// Summary\n/// Description for I1\npublic record struct C(int I1);\n\nnamespace System.Runtime.CompilerServices\n{\n /// Ignored\n public static class IsExternalInit\n {\n }\n}\n\";\n\n var comp = CreateCompilation(src, parseOptions: TestOptions.RegularWithDocumentationComments);\n comp.VerifyDiagnostics();\n\n var cMember = comp.GetMember(\"C\");\n Assert.Equal(\n@\"\n Summary\n Description for I1\n\n\", cMember.GetDocumentationCommentXml());\n var constructor = cMember.GetMembers(\".ctor\").OfType().Single();\n Assert.Equal(\n@\"\n Summary\n Description for I1\n\n\", constructor.GetDocumentationCommentXml());\n\n Assert.Equal(\"\", constructor.GetParameters()[0].GetDocumentationCommentXml());\n\n var property = cMember.GetMembers(\"I1\").Single();\n Assert.Equal(\"\", property.GetDocumentationCommentXml());\n }\n\n [Fact]\n public void XmlDoc_Cref()\n {\n var src = @\"\n/// Summary\n/// Description for \npublic record struct C(int I1)\n{\n /// Summary\n /// Description for \n public void M(int x) { }\n}\n\nnamespace System.Runtime.CompilerServices\n{\n /// Ignored\n public static class IsExternalInit\n {\n }\n}\n\";\n\n var comp = CreateCompilation(src, parseOptions: TestOptions.RegularWithDocumentationComments);\n comp.VerifyDiagnostics(\n // (7,52): warning CS1574: XML comment has cref attribute 'x' that could not be resolved\n // /// Description for \n Diagnostic(ErrorCode.WRN_BadXMLRef, \"x\").WithArguments(\"x\").WithLocation(7, 52)\n );\n\n var tree = comp.SyntaxTrees.Single();\n var docComments = tree.GetCompilationUnitRoot().DescendantTrivia().Select(trivia => trivia.GetStructure()).OfType();\n var cref = docComments.First().DescendantNodes().OfType().First().Cref;\n Assert.Equal(\"I1\", cref.ToString());\n\n var model = comp.GetSemanticModel(tree, ignoreAccessibility: false);\n Assert.Equal(SymbolKind.Property, model.GetSymbolInfo(cref).Symbol!.Kind);\n }\n\n [Fact]\n public void Deconstruct_Simple()\n {\n var source =\n@\"using System;\n\nrecord struct B(int X, int Y)\n{\n public static void Main()\n {\n M(new B(1, 2));\n }\n\n static void M(B b)\n {\n switch (b)\n {\n case B(int x, int y):\n Console.Write(x);\n Console.Write(y);\n break;\n }\n }\n}\";\n var verifier = CompileAndVerify(source, expectedOutput: \"12\");\n verifier.VerifyDiagnostics();\n\n verifier.VerifyIL(\"B.Deconstruct\", @\"\n{\n // Code size 17 (0x11)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: ldarg.0\n IL_0002: call \"\"readonly int B.X.get\"\"\n IL_0007: stind.i4\n IL_0008: ldarg.2\n IL_0009: ldarg.0\n IL_000a: call \"\"readonly int B.Y.get\"\"\n IL_000f: stind.i4\n IL_0010: ret\n}\");\n\n var deconstruct = ((CSharpCompilation)verifier.Compilation).GetMember(\"B.Deconstruct\");\n Assert.Equal(2, deconstruct.ParameterCount);\n\n Assert.Equal(RefKind.Out, deconstruct.Parameters[0].RefKind);\n Assert.Equal(\"X\", deconstruct.Parameters[0].Name);\n\n Assert.Equal(RefKind.Out, deconstruct.Parameters[1].RefKind);\n Assert.Equal(\"Y\", deconstruct.Parameters[1].Name);\n\n Assert.True(deconstruct.ReturnsVoid);\n Assert.False(deconstruct.IsVirtual);\n Assert.False(deconstruct.IsStatic);\n Assert.Equal(Accessibility.Public, deconstruct.DeclaredAccessibility);\n }\n\n [Fact]\n public void Deconstruct_PositionalAndNominalProperty()\n {\n var source =\n@\"using System;\n\nrecord struct B(int X)\n{\n public int Y { get; init; } = 0;\n\n public static void Main()\n {\n M(new B(1));\n }\n\n static void M(B b)\n {\n switch (b)\n {\n case B(int x):\n Console.Write(x);\n break;\n }\n }\n}\";\n var verifier = CompileAndVerify(source, expectedOutput: \"1\");\n verifier.VerifyDiagnostics();\n\n Assert.Equal(\n \"readonly void B.Deconstruct(out System.Int32 X)\",\n verifier.Compilation.GetMember(\"B.Deconstruct\").ToTestDisplayString(includeNonNullable: false));\n }\n\n [Fact]\n public void Deconstruct_Nested()\n {\n var source =\n@\"using System;\n\nrecord struct B(int X, int Y);\n\nrecord struct C(B B, int Z)\n{\n public static void Main()\n {\n M(new C(new B(1, 2), 3));\n }\n\n static void M(C c)\n {\n switch (c)\n {\n case C(B(int x, int y), int z):\n Console.Write(x);\n Console.Write(y);\n Console.Write(z);\n break;\n }\n }\n}\n\";\n\n var verifier = CompileAndVerify(source, expectedOutput: \"123\");\n verifier.VerifyDiagnostics();\n\n verifier.VerifyIL(\"B.Deconstruct\", @\"\n{\n // Code size 17 (0x11)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: ldarg.0\n IL_0002: call \"\"readonly int B.X.get\"\"\n IL_0007: stind.i4\n IL_0008: ldarg.2\n IL_0009: ldarg.0\n IL_000a: call \"\"readonly int B.Y.get\"\"\n IL_000f: stind.i4\n IL_0010: ret\n}\");\n\n verifier.VerifyIL(\"C.Deconstruct\", @\"\n{\n // Code size 21 (0x15)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: ldarg.0\n IL_0002: call \"\"readonly B C.B.get\"\"\n IL_0007: stobj \"\"B\"\"\n IL_000c: ldarg.2\n IL_000d: ldarg.0\n IL_000e: call \"\"readonly int C.Z.get\"\"\n IL_0013: stind.i4\n IL_0014: ret\n}\");\n }\n\n [Fact]\n public void Deconstruct_PropertyCollision()\n {\n var source =\n@\"using System;\n\nrecord struct B(int X, int Y)\n{\n public int X => 3;\n\n static void M(B b)\n {\n switch (b)\n {\n case B(int x, int y):\n Console.Write(x);\n Console.Write(y);\n break;\n }\n }\n\n static void Main()\n {\n M(new B(1, 2));\n }\n}\n\";\n var verifier = CompileAndVerify(source, expectedOutput: \"32\");\n verifier.VerifyDiagnostics(\n // (3,21): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct B(int X, int Y)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(3, 21)\n );\n\n Assert.Equal(\n \"void B.Deconstruct(out System.Int32 X, out System.Int32 Y)\",\n verifier.Compilation.GetMember(\"B.Deconstruct\").ToTestDisplayString(includeNonNullable: false));\n }\n\n [Fact]\n public void Deconstruct_MethodCollision_01()\n {\n var source = @\"\nrecord struct B(int X, int Y)\n{\n public int X() => 3;\n\n static void M(B b)\n {\n switch (b)\n {\n case B(int x, int y):\n break;\n }\n }\n\n static void Main()\n {\n M(new B(1, 2));\n }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (4,16): error CS0102: The type 'B' already contains a definition for 'X'\n // public int X() => 3;\n Diagnostic(ErrorCode.ERR_DuplicateNameInClass, \"X\").WithArguments(\"B\", \"X\").WithLocation(4, 16)\n );\n\n Assert.Equal(\n \"readonly void B.Deconstruct(out System.Int32 X, out System.Int32 Y)\",\n comp.GetMember(\"B.Deconstruct\").ToTestDisplayString(includeNonNullable: false));\n }\n\n [Fact]\n public void Deconstruct_FieldCollision()\n {\n var source = @\"\nusing System;\n\nrecord struct C(int X)\n{\n int X = 0;\n\n static void M(C c)\n {\n switch (c)\n {\n case C(int x):\n Console.Write(x);\n break;\n }\n }\n\n static void Main()\n {\n M(new C(0));\n }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (4,21): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(int X)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(4, 21),\n // (6,9): warning CS0414: The field 'C.X' is assigned but its value is never used\n // int X = 0;\n Diagnostic(ErrorCode.WRN_UnreferencedFieldAssg, \"X\").WithArguments(\"C.X\").WithLocation(6, 9));\n\n Assert.Equal(\n \"readonly void C.Deconstruct(out System.Int32 X)\",\n comp.GetMember(\"C.Deconstruct\").ToTestDisplayString(includeNonNullable: false));\n }\n\n [Fact]\n public void Deconstruct_Empty()\n {\n var source = @\"\nrecord struct C\n{\n static void M(C c)\n {\n switch (c)\n {\n case C():\n break;\n }\n }\n\n static void Main()\n {\n M(new C());\n }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (8,19): error CS1061: 'C' does not contain a definition for 'Deconstruct' and no accessible extension method 'Deconstruct' accepting a first argument of type 'C' could be found (are you missing a using directive or an assembly reference?)\n // case C():\n Diagnostic(ErrorCode.ERR_NoSuchMemberOrExtension, \"()\").WithArguments(\"C\", \"Deconstruct\").WithLocation(8, 19),\n // (8,19): error CS8129: No suitable 'Deconstruct' instance or extension method was found for type 'C', with 0 out parameters and a void return type.\n // case C():\n Diagnostic(ErrorCode.ERR_MissingDeconstruct, \"()\").WithArguments(\"C\", \"0\").WithLocation(8, 19));\n\n Assert.Null(comp.GetMember(\"C.Deconstruct\"));\n }\n\n [Fact]\n public void Deconstruct_Conversion_02()\n {\n var source = @\"\n#nullable enable\nusing System;\n\nrecord struct C(string? X, string Y)\n{\n public string X { get; init; } = null!;\n public string? Y { get; init; } = string.Empty;\n\n static void M(C c)\n {\n switch (c)\n {\n case C(var x, string y):\n Console.Write(x);\n Console.Write(y);\n break;\n }\n }\n\n static void Main()\n {\n M(new C(\"\"a\"\", \"\"b\"\"));\n }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (5,25): warning CS8907: Parameter 'X' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(string? X, string Y)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"X\").WithArguments(\"X\").WithLocation(5, 25),\n // (5,35): warning CS8907: Parameter 'Y' is unread. Did you forget to use it to initialize the property with that name?\n // record struct C(string? X, string Y)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"Y\").WithArguments(\"Y\").WithLocation(5, 35)\n );\n\n Assert.Equal(\n \"readonly void C.Deconstruct(out System.String? X, out System.String Y)\",\n comp.GetMember(\"C.Deconstruct\").ToTestDisplayString(includeNonNullable: false));\n }\n\n [Fact]\n public void Deconstruct_Empty_WithParameterList()\n {\n var source = @\"\nrecord struct C()\n{\n static void M(C c)\n {\n switch (c)\n {\n case C():\n break;\n }\n }\n\n static void Main()\n {\n M(new C());\n }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (8,19): error CS1061: 'C' does not contain a definition for 'Deconstruct' and no accessible extension method 'Deconstruct' accepting a first argument of type 'C' could be found (are you missing a using directive or an assembly reference?)\n // case C():\n Diagnostic(ErrorCode.ERR_NoSuchMemberOrExtension, \"()\").WithArguments(\"C\", \"Deconstruct\").WithLocation(8, 19),\n // (8,19): error CS8129: No suitable 'Deconstruct' instance or extension method was found for type 'C', with 0 out parameters and a void return type.\n // case C():\n Diagnostic(ErrorCode.ERR_MissingDeconstruct, \"()\").WithArguments(\"C\", \"0\").WithLocation(8, 19));\n\n AssertEx.Equal(new[] {\n \"C..ctor()\",\n \"void C.M(C c)\",\n \"void C.Main()\",\n \"readonly System.String C.ToString()\",\n \"readonly System.Boolean C.PrintMembers(System.Text.StringBuilder builder)\",\n \"System.Boolean C.op_Inequality(C left, C right)\",\n \"System.Boolean C.op_Equality(C left, C right)\",\n \"readonly System.Int32 C.GetHashCode()\",\n \"readonly System.Boolean C.Equals(System.Object obj)\",\n \"readonly System.Boolean C.Equals(C other)\" },\n comp.GetMember(\"C\").GetMembers().ToTestDisplayStrings());\n }\n\n [Fact]\n public void Deconstruct_Empty_WithParameterList_UserDefined_01()\n {\n var source =\n@\"using System;\n\nrecord struct C(int I)\n{\n public void Deconstruct()\n {\n }\n\n static void M(C c)\n {\n switch (c)\n {\n case C():\n Console.Write(12);\n break;\n }\n }\n\n public static void Main()\n {\n M(new C(42));\n }\n}\n\";\n var verifier = CompileAndVerify(source, expectedOutput: \"12\");\n verifier.VerifyDiagnostics();\n }\n\n [Fact]\n public void Deconstruct_GeneratedAsReadOnly()\n {\n var src = @\"\nrecord struct A(int I, string S);\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n var method = comp.GetMember(\"A.Deconstruct\");\n Assert.True(method.IsDeclaredReadOnly);\n }\n\n [Fact]\n public void Deconstruct_WihtNonReadOnlyGetter_GeneratedAsNonReadOnly()\n {\n var src = @\"\nrecord struct A(int I, string S)\n{\n public int I { get => 0; }\n}\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (2,21): warning CS8907: Parameter 'I' is unread. Did you forget to use it to initialize the property with that name?\n // record struct A(int I, string S)\n Diagnostic(ErrorCode.WRN_UnreadRecordParameter, \"I\").WithArguments(\"I\").WithLocation(2, 21));\n var method = comp.GetMember(\"A.Deconstruct\");\n Assert.False(method.IsDeclaredReadOnly);\n }\n\n [Fact]\n public void Deconstruct_UserDefined()\n {\n var source =\n@\"using System;\n\nrecord struct B(int X, int Y)\n{\n public void Deconstruct(out int X, out int Y)\n {\n X = this.X + 1;\n Y = this.Y + 2;\n }\n\n static void M(B b)\n {\n switch (b)\n {\n case B(int x, int y):\n Console.Write(x);\n Console.Write(y);\n break;\n }\n }\n\n public static void Main()\n {\n M(new B(0, 0));\n }\n}\n\";\n var verifier = CompileAndVerify(source, expectedOutput: \"12\");\n verifier.VerifyDiagnostics();\n }\n\n [Fact]\n public void Deconstruct_UserDefined_DifferentSignature_02()\n {\n var source =\n@\"using System;\n\nrecord struct B(int X)\n{\n public int Deconstruct(out int a) => throw null;\n\n static void M(B b)\n {\n switch (b)\n {\n case B(int x):\n Console.Write(x);\n break;\n }\n }\n\n public static void Main()\n {\n M(new B(1));\n }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (5,16): error CS8874: Record member 'B.Deconstruct(out int)' must return 'void'.\n // public int Deconstruct(out int a) => throw null;\n Diagnostic(ErrorCode.ERR_SignatureMismatchInRecord, \"Deconstruct\").WithArguments(\"B.Deconstruct(out int)\", \"void\").WithLocation(5, 16),\n // (11,19): error CS8129: No suitable 'Deconstruct' instance or extension method was found for type 'B', with 1 out parameters and a void return type.\n // case B(int x):\n Diagnostic(ErrorCode.ERR_MissingDeconstruct, \"(int x)\").WithArguments(\"B\", \"1\").WithLocation(11, 19));\n\n Assert.Equal(\"System.Int32 B.Deconstruct(out System.Int32 a)\", comp.GetMember(\"B.Deconstruct\").ToTestDisplayString(includeNonNullable: false));\n }\n\n [Theory]\n [InlineData(\"\")]\n [InlineData(\"private\")]\n [InlineData(\"internal\")]\n public void Deconstruct_UserDefined_Accessibility_07(string accessibility)\n {\n var source =\n$@\"\nrecord struct A(int X)\n{{\n { accessibility } void Deconstruct(out int a)\n => throw null;\n}}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,11): error CS8873: Record member 'A.Deconstruct(out int)' must be public.\n // void Deconstruct(out int a)\n Diagnostic(ErrorCode.ERR_NonPublicAPIInRecord, \"Deconstruct\").WithArguments(\"A.Deconstruct(out int)\").WithLocation(4, 11 + accessibility.Length)\n );\n }\n\n [Fact]\n public void Deconstruct_UserDefined_Static_08()\n {\n var source =\n@\"\nrecord struct A(int X)\n{\n public static void Deconstruct(out int a)\n => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,24): error CS8877: Record member 'A.Deconstruct(out int)' may not be static.\n // public static void Deconstruct(out int a)\n Diagnostic(ErrorCode.ERR_StaticAPIInRecord, \"Deconstruct\").WithArguments(\"A.Deconstruct(out int)\").WithLocation(4, 24)\n );\n }\n\n [Fact]\n public void OutVarInPositionalParameterDefaultValue()\n {\n var source =\n@\"\nrecord struct A(int X = A.M(out int a) + a)\n{\n public static int M(out int a)\n => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (2,25): error CS1736: Default parameter value for 'X' must be a compile-time constant\n // record struct A(int X = A.M(out int a) + a)\n Diagnostic(ErrorCode.ERR_DefaultValueMustBeConstant, \"A.M(out int a) + a\").WithArguments(\"X\").WithLocation(2, 25)\n );\n }\n\n [Fact]\n public void FieldConsideredUnassignedIfInitializationViaProperty()\n {\n var source = @\"\nrecord struct Pos(int X)\n{\n private int x;\n public int X { get { return x; } set { x = value; } } = X;\n}\n\nrecord struct Pos2(int X)\n{\n private int x = X; // value isn't validated by setter\n public int X { get { return x; } set { x = value; } }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (2,15): error CS0171: Field 'Pos.x' must be fully assigned before control is returned to the caller\n // record struct Pos(int X)\n Diagnostic(ErrorCode.ERR_UnassignedThis, \"Pos\").WithArguments(\"Pos.x\").WithLocation(2, 15),\n // (5,16): error CS8050: Only auto-implemented properties can have initializers.\n // public int X { get { return x; } set { x = value; } } = X;\n Diagnostic(ErrorCode.ERR_InitializerOnNonAutoProperty, \"X\").WithArguments(\"Pos.X\").WithLocation(5, 16)\n );\n }\n\n [Fact]\n public void IEquatableT_01()\n {\n var source =\n@\"record struct A;\nclass Program\n{\n static void F(System.IEquatable t)\n {\n }\n static void M()\n {\n F(new A());\n }\n}\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n );\n }\n\n [Fact]\n public void IEquatableT_02()\n {\n var source =\n@\"using System;\nrecord struct A;\nrecord struct B;\n\nclass Program\n{\n static bool F(IEquatable t, T t2)\n {\n return t.Equals(t2);\n }\n static void Main()\n {\n Console.Write(F(new A(), new A()));\n Console.Write(F(new B(), new B()));\n }\n}\";\n var comp = CreateCompilation(new[] { source, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.ReleaseExe);\n CompileAndVerify(comp, expectedOutput: \"TrueTrue\").VerifyDiagnostics();\n }\n\n [Fact]\n public void IEquatableT_02_ImplicitImplementation()\n {\n var source =\n@\"using System;\nrecord struct A\n{\n public bool Equals(A other)\n {\n System.Console.Write(\"\"A.Equals(A) \"\");\n return false;\n }\n}\nrecord struct B\n{\n public bool Equals(B other)\n {\n System.Console.Write(\"\"B.Equals(B) \"\");\n return true;\n }\n}\n\nclass Program\n{\n static bool F(IEquatable t, T t2)\n {\n return t.Equals(t2);\n }\n static void Main()\n {\n Console.Write(F(new A(), new A()));\n Console.Write(\"\" \"\");\n Console.Write(F(new B(), new B()));\n }\n}\";\n var comp = CreateCompilation(new[] { source, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.ReleaseExe);\n CompileAndVerify(comp, expectedOutput: \"A.Equals(A) False B.Equals(B) True\").VerifyDiagnostics(\n // (4,17): warning CS8851: 'A' defines 'Equals' but not 'GetHashCode'\n // public bool Equals(A other)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"A\").WithLocation(4, 17),\n // (12,17): warning CS8851: 'B' defines 'Equals' but not 'GetHashCode'\n // public bool Equals(B other)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"B\").WithLocation(12, 17)\n );\n }\n\n [Fact]\n public void IEquatableT_02_ExplicitImplementation()\n {\n var source =\n@\"using System;\nrecord struct A\n{\n bool IEquatable.Equals(A other)\n {\n System.Console.Write(\"\"A.Equals(A) \"\");\n return false;\n }\n}\nrecord struct B\n{\n bool IEquatable>.Equals(B other)\n {\n System.Console.Write(\"\"B.Equals(B) \"\");\n return true;\n }\n}\n\nclass Program\n{\n static bool F(IEquatable t, T t2)\n {\n return t.Equals(t2);\n }\n static void Main()\n {\n Console.Write(F(new A(), new A()));\n Console.Write(\"\" \"\");\n Console.Write(F(new B(), new B()));\n }\n}\";\n var comp = CreateCompilation(new[] { source, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.ReleaseExe);\n CompileAndVerify(comp, expectedOutput: \"A.Equals(A) False B.Equals(B) True\").VerifyDiagnostics();\n }\n\n [Fact]\n public void IEquatableT_03()\n {\n var source = @\"\nrecord struct A : System.IEquatable>;\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics();\n\n var type = comp.GetMember(\"A\");\n AssertEx.Equal(new[] { \"System.IEquatable>\" }, type.InterfacesNoUseSiteDiagnostics().ToTestDisplayStrings());\n AssertEx.Equal(new[] { \"System.IEquatable>\" }, type.AllInterfacesNoUseSiteDiagnostics.ToTestDisplayStrings());\n }\n\n [Fact]\n public void IEquatableT_MissingIEquatable()\n {\n var source = @\"\nrecord struct A;\n\";\n var comp = CreateCompilation(source);\n comp.MakeTypeMissing(WellKnownType.System_IEquatable_T);\n comp.VerifyEmitDiagnostics(\n // (2,15): error CS0518: Predefined type 'System.IEquatable`1' is not defined or imported\n // record struct A;\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"A\").WithArguments(\"System.IEquatable`1\").WithLocation(2, 15),\n // (2,15): error CS0518: Predefined type 'System.IEquatable`1' is not defined or imported\n // record struct A;\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"A\").WithArguments(\"System.IEquatable`1\").WithLocation(2, 15)\n );\n\n var type = comp.GetMember(\"A\");\n AssertEx.Equal(new[] { \"System.IEquatable>[missing]\" }, type.InterfacesNoUseSiteDiagnostics().ToTestDisplayStrings());\n AssertEx.Equal(new[] { \"System.IEquatable>[missing]\" }, type.AllInterfacesNoUseSiteDiagnostics.ToTestDisplayStrings());\n }\n\n [Fact]\n public void RecordEquals_01()\n {\n var source = @\"\nvar a1 = new B();\nvar a2 = new B();\nSystem.Console.WriteLine(a1.Equals(a2));\n\nrecord struct B\n{\n public bool Equals(B other)\n {\n System.Console.WriteLine(\"\"B.Equals(B)\"\");\n return false;\n }\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics(\n // (8,17): warning CS8851: 'B' defines 'Equals' but not 'GetHashCode'\n // public bool Equals(B other)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"B\").WithLocation(8, 17)\n );\n\n CompileAndVerify(comp, expectedOutput:\n@\"\nB.Equals(B)\nFalse\n\");\n }\n\n [Fact]\n public void RecordEquals_01_NoInParameters()\n {\n var source = @\"\nvar a1 = new B();\nvar a2 = new B();\nSystem.Console.WriteLine(a1.Equals(in a2));\n\nrecord struct B;\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,39): error CS1615: Argument 1 may not be passed with the 'in' keyword\n // System.Console.WriteLine(a1.Equals(in a2));\n Diagnostic(ErrorCode.ERR_BadArgExtraRef, \"a2\").WithArguments(\"1\", \"in\").WithLocation(4, 39)\n );\n }\n\n [Theory]\n [InlineData(\"protected\")]\n [InlineData(\"private protected\")]\n [InlineData(\"internal protected\")]\n public void RecordEquals_10(string accessibility)\n {\n var source =\n$@\"\nrecord struct A\n{{\n { accessibility } bool Equals(A x)\n => throw null;\n\n bool System.IEquatable.Equals(A x) => throw null;\n}}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,29): error CS0666: 'A.Equals(A)': new protected member declared in struct\n // internal protected bool Equals(A x)\n Diagnostic(ErrorCode.ERR_ProtectedInStruct, \"Equals\").WithArguments(\"A.Equals(A)\").WithLocation(4, 11 + accessibility.Length),\n // (4,29): error CS8873: Record member 'A.Equals(A)' must be public.\n // internal protected bool Equals(A x)\n Diagnostic(ErrorCode.ERR_NonPublicAPIInRecord, \"Equals\").WithArguments(\"A.Equals(A)\").WithLocation(4, 11 + accessibility.Length),\n // (4,29): warning CS8851: 'A' defines 'Equals' but not 'GetHashCode'\n // internal protected bool Equals(A x)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"A\").WithLocation(4, 11 + accessibility.Length)\n );\n }\n\n [Theory]\n [InlineData(\"\")]\n [InlineData(\"private\")]\n [InlineData(\"internal\")]\n public void RecordEquals_11(string accessibility)\n {\n var source =\n$@\"\nrecord struct A\n{{\n { accessibility } bool Equals(A x)\n => throw null;\n\n bool System.IEquatable.Equals(A x) => throw null;\n}}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,...): error CS8873: Record member 'A.Equals(A)' must be public.\n // { accessibility } bool Equals(A x)\n Diagnostic(ErrorCode.ERR_NonPublicAPIInRecord, \"Equals\").WithArguments(\"A.Equals(A)\").WithLocation(4, 11 + accessibility.Length),\n // (4,11): warning CS8851: 'A' defines 'Equals' but not 'GetHashCode'\n // bool Equals(A x)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"A\").WithLocation(4, 11 + accessibility.Length)\n );\n }\n\n [Fact]\n public void RecordEquals_12()\n {\n var source = @\"\nA a1 = new A();\nA a2 = new A();\n\nSystem.Console.Write(a1.Equals(a2));\nSystem.Console.Write(a1.Equals((object)a2));\n\nrecord struct A\n{\n public bool Equals(B other) => throw null;\n}\nclass B\n{\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics();\n var verifier = CompileAndVerify(comp, expectedOutput: \"TrueTrue\");\n verifier.VerifyIL(\"A.Equals(A)\", @\"\n{\n // Code size 2 (0x2)\n .maxstack 1\n IL_0000: ldc.i4.1\n IL_0001: ret\n}\");\n\n verifier.VerifyIL(\"A.Equals(object)\", @\"\n{\n // Code size 23 (0x17)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: isinst \"\"A\"\"\n IL_0006: brfalse.s IL_0015\n IL_0008: ldarg.0\n IL_0009: ldarg.1\n IL_000a: unbox.any \"\"A\"\"\n IL_000f: call \"\"readonly bool A.Equals(A)\"\"\n IL_0014: ret\n IL_0015: ldc.i4.0\n IL_0016: ret\n}\");\n\n verifier.VerifyIL(\"A.GetHashCode()\", @\"\n{\n // Code size 2 (0x2)\n .maxstack 1\n IL_0000: ldc.i4.0\n IL_0001: ret\n}\");\n\n var recordEquals = comp.GetMembers(\"A.Equals\").OfType().Single();\n Assert.Equal(\"readonly System.Boolean A.Equals(A other)\", recordEquals.ToTestDisplayString());\n Assert.Equal(Accessibility.Public, recordEquals.DeclaredAccessibility);\n Assert.False(recordEquals.IsAbstract);\n Assert.False(recordEquals.IsVirtual);\n Assert.False(recordEquals.IsOverride);\n Assert.False(recordEquals.IsSealed);\n Assert.True(recordEquals.IsImplicitlyDeclared);\n\n var objectEquals = comp.GetMembers(\"A.Equals\").OfType().Single();\n Assert.Equal(\"readonly System.Boolean A.Equals(System.Object obj)\", objectEquals.ToTestDisplayString());\n Assert.Equal(Accessibility.Public, objectEquals.DeclaredAccessibility);\n Assert.False(objectEquals.IsAbstract);\n Assert.False(objectEquals.IsVirtual);\n Assert.True(objectEquals.IsOverride);\n Assert.False(objectEquals.IsSealed);\n Assert.True(objectEquals.IsImplicitlyDeclared);\n\n MethodSymbol gethashCode = comp.GetMembers(\"A.\" + WellKnownMemberNames.ObjectGetHashCode).OfType().Single();\n Assert.Equal(\"readonly System.Int32 A.GetHashCode()\", gethashCode.ToTestDisplayString());\n Assert.Equal(Accessibility.Public, gethashCode.DeclaredAccessibility);\n Assert.False(gethashCode.IsStatic);\n Assert.False(gethashCode.IsAbstract);\n Assert.False(gethashCode.IsVirtual);\n Assert.True(gethashCode.IsOverride);\n Assert.False(gethashCode.IsSealed);\n Assert.True(gethashCode.IsImplicitlyDeclared);\n }\n\n [Fact]\n public void RecordEquals_13()\n {\n var source = @\"\nrecord struct A\n{\n public int Equals(A other)\n => throw null;\n\n bool System.IEquatable.Equals(A x) => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,16): error CS8874: Record member 'A.Equals(A)' must return 'bool'.\n // public int Equals(A other)\n Diagnostic(ErrorCode.ERR_SignatureMismatchInRecord, \"Equals\").WithArguments(\"A.Equals(A)\", \"bool\").WithLocation(4, 16),\n // (4,16): warning CS8851: 'A' defines 'Equals' but not 'GetHashCode'\n // public int Equals(A other)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"A\").WithLocation(4, 16)\n );\n }\n\n [Fact]\n public void RecordEquals_14()\n {\n var source = @\"\nrecord struct A\n{\n public bool Equals(A other)\n => throw null;\n\n System.Boolean System.IEquatable.Equals(A x) => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.MakeTypeMissing(SpecialType.System_Boolean);\n comp.VerifyEmitDiagnostics(\n // (2,1): error CS0518: Predefined type 'System.Boolean' is not defined or imported\n // record struct A\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, @\"record struct A\n{\n public bool Equals(A other)\n => throw null;\n\n System.Boolean System.IEquatable.Equals(A x) => throw null;\n}\").WithArguments(\"System.Boolean\").WithLocation(2, 1),\n // (2,1): error CS0518: Predefined type 'System.Boolean' is not defined or imported\n // record struct A\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, @\"record struct A\n{\n public bool Equals(A other)\n => throw null;\n\n System.Boolean System.IEquatable.Equals(A x) => throw null;\n}\").WithArguments(\"System.Boolean\").WithLocation(2, 1),\n // (2,15): error CS0518: Predefined type 'System.Boolean' is not defined or imported\n // record struct A\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"A\").WithArguments(\"System.Boolean\").WithLocation(2, 15),\n // (2,15): error CS0518: Predefined type 'System.Boolean' is not defined or imported\n // record struct A\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"A\").WithArguments(\"System.Boolean\").WithLocation(2, 15),\n // (2,15): error CS0518: Predefined type 'System.Boolean' is not defined or imported\n // record struct A\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"A\").WithArguments(\"System.Boolean\").WithLocation(2, 15),\n // (2,15): error CS0518: Predefined type 'System.Boolean' is not defined or imported\n // record struct A\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"A\").WithArguments(\"System.Boolean\").WithLocation(2, 15),\n // (4,12): error CS0518: Predefined type 'System.Boolean' is not defined or imported\n // public bool Equals(A other)\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"bool\").WithArguments(\"System.Boolean\").WithLocation(4, 12),\n // (4,17): warning CS8851: 'A' defines 'Equals' but not 'GetHashCode'\n // public bool Equals(A other)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"A\").WithLocation(4, 17)\n );\n }\n\n [Fact]\n public void RecordEquals_19()\n {\n var source = @\"\nrecord struct A\n{\n public static bool Equals(A x) => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (2,15): error CS0736: 'A' does not implement interface member 'IEquatable.Equals(A)'. 'A.Equals(A)' cannot implement an interface member because it is static.\n // record struct A\n Diagnostic(ErrorCode.ERR_CloseUnimplementedInterfaceMemberStatic, \"A\").WithArguments(\"A\", \"System.IEquatable.Equals(A)\", \"A.Equals(A)\").WithLocation(2, 15),\n // (4,24): error CS8877: Record member 'A.Equals(A)' may not be static.\n // public static bool Equals(A x) => throw null;\n Diagnostic(ErrorCode.ERR_StaticAPIInRecord, \"Equals\").WithArguments(\"A.Equals(A)\").WithLocation(4, 24),\n // (4,24): warning CS8851: 'A' defines 'Equals' but not 'GetHashCode'\n // public static bool Equals(A x) => throw null;\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"A\").WithLocation(4, 24)\n );\n }\n\n [Fact]\n public void RecordEquals_RecordEqualsInValueType()\n {\n var src = @\"\npublic record struct A;\n\nnamespace System\n{\n public class Object\n {\n public virtual bool Equals(object x) => throw null;\n public virtual int GetHashCode() => throw null;\n public virtual string ToString() => throw null;\n }\n public class Exception { }\n public class ValueType\n {\n public bool Equals(A x) => throw null;\n }\n public class Attribute { }\n public class String { }\n public struct Void { }\n public struct Boolean { }\n public struct Char { }\n public struct Int32 { }\n public interface IEquatable { }\n}\nnamespace System.Collections.Generic\n{\n public abstract class EqualityComparer\n {\n public static EqualityComparer Default => throw null;\n public abstract int GetHashCode(T t);\n }\n}\nnamespace System.Text\n{\n public class StringBuilder\n {\n public StringBuilder Append(string s) => null;\n public StringBuilder Append(char c) => null;\n public StringBuilder Append(object o) => null;\n }\n}\n\";\n var comp = CreateEmptyCompilation(src, parseOptions: TestOptions.RegularPreview);\n\n comp.VerifyEmitDiagnostics(\n // warning CS8021: No value for RuntimeMetadataVersion found. No assembly containing System.Object was found nor was a value for RuntimeMetadataVersion specified through options.\n Diagnostic(ErrorCode.WRN_NoRuntimeMetadataVersion).WithLocation(1, 1)\n );\n\n var recordEquals = comp.GetMembers(\"A.Equals\").OfType().Single();\n Assert.Equal(\"readonly System.Boolean A.Equals(A other)\", recordEquals.ToTestDisplayString());\n }\n\n [Fact]\n public void RecordEquals_FourFields()\n {\n var source = @\"\nA a1 = new A(1, \"\"hello\"\");\n\nSystem.Console.Write(a1.Equals(a1));\nSystem.Console.Write(a1.Equals((object)a1));\nSystem.Console.Write(\"\" - \"\");\n\nA a2 = new A(1, \"\"hello\"\") { fieldI = 100 };\n\nSystem.Console.Write(a1.Equals(a2));\nSystem.Console.Write(a1.Equals((object)a2));\nSystem.Console.Write(a2.Equals(a1));\nSystem.Console.Write(a2.Equals((object)a1));\nSystem.Console.Write(\"\" - \"\");\n\nA a3 = new A(1, \"\"world\"\");\n\nSystem.Console.Write(a1.Equals(a3));\nSystem.Console.Write(a1.Equals((object)a3));\nSystem.Console.Write(a3.Equals(a1));\nSystem.Console.Write(a3.Equals((object)a1));\n\nrecord struct A(int I, string S)\n{\n public int fieldI = 42;\n public string fieldS = \"\"hello\"\";\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics();\n var verifier = CompileAndVerify(comp, expectedOutput: \"TrueTrue - FalseFalseFalseFalse - FalseFalseFalseFalse\");\n verifier.VerifyIL(\"A.Equals(A)\", @\"\n{\n // Code size 97 (0x61)\n .maxstack 3\n IL_0000: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_0005: ldarg.0\n IL_0006: ldfld \"\"int A.k__BackingField\"\"\n IL_000b: ldarg.1\n IL_000c: ldfld \"\"int A.k__BackingField\"\"\n IL_0011: callvirt \"\"bool System.Collections.Generic.EqualityComparer.Equals(int, int)\"\"\n IL_0016: brfalse.s IL_005f\n IL_0018: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_001d: ldarg.0\n IL_001e: ldfld \"\"string A.k__BackingField\"\"\n IL_0023: ldarg.1\n IL_0024: ldfld \"\"string A.k__BackingField\"\"\n IL_0029: callvirt \"\"bool System.Collections.Generic.EqualityComparer.Equals(string, string)\"\"\n IL_002e: brfalse.s IL_005f\n IL_0030: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_0035: ldarg.0\n IL_0036: ldfld \"\"int A.fieldI\"\"\n IL_003b: ldarg.1\n IL_003c: ldfld \"\"int A.fieldI\"\"\n IL_0041: callvirt \"\"bool System.Collections.Generic.EqualityComparer.Equals(int, int)\"\"\n IL_0046: brfalse.s IL_005f\n IL_0048: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_004d: ldarg.0\n IL_004e: ldfld \"\"string A.fieldS\"\"\n IL_0053: ldarg.1\n IL_0054: ldfld \"\"string A.fieldS\"\"\n IL_0059: callvirt \"\"bool System.Collections.Generic.EqualityComparer.Equals(string, string)\"\"\n IL_005e: ret\n IL_005f: ldc.i4.0\n IL_0060: ret\n}\");\n\n verifier.VerifyIL(\"A.Equals(object)\", @\"\n{\n // Code size 23 (0x17)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: isinst \"\"A\"\"\n IL_0006: brfalse.s IL_0015\n IL_0008: ldarg.0\n IL_0009: ldarg.1\n IL_000a: unbox.any \"\"A\"\"\n IL_000f: call \"\"readonly bool A.Equals(A)\"\"\n IL_0014: ret\n IL_0015: ldc.i4.0\n IL_0016: ret\n}\");\n\n verifier.VerifyIL(\"A.GetHashCode()\", @\"\n{\n // Code size 86 (0x56)\n .maxstack 3\n IL_0000: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_0005: ldarg.0\n IL_0006: ldfld \"\"int A.k__BackingField\"\"\n IL_000b: callvirt \"\"int System.Collections.Generic.EqualityComparer.GetHashCode(int)\"\"\n IL_0010: ldc.i4 0xa5555529\n IL_0015: mul\n IL_0016: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_001b: ldarg.0\n IL_001c: ldfld \"\"string A.k__BackingField\"\"\n IL_0021: callvirt \"\"int System.Collections.Generic.EqualityComparer.GetHashCode(string)\"\"\n IL_0026: add\n IL_0027: ldc.i4 0xa5555529\n IL_002c: mul\n IL_002d: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_0032: ldarg.0\n IL_0033: ldfld \"\"int A.fieldI\"\"\n IL_0038: callvirt \"\"int System.Collections.Generic.EqualityComparer.GetHashCode(int)\"\"\n IL_003d: add\n IL_003e: ldc.i4 0xa5555529\n IL_0043: mul\n IL_0044: call \"\"System.Collections.Generic.EqualityComparer System.Collections.Generic.EqualityComparer.Default.get\"\"\n IL_0049: ldarg.0\n IL_004a: ldfld \"\"string A.fieldS\"\"\n IL_004f: callvirt \"\"int System.Collections.Generic.EqualityComparer.GetHashCode(string)\"\"\n IL_0054: add\n IL_0055: ret\n}\");\n }\n\n [Fact]\n public void RecordEquals_StaticField()\n {\n var source = @\"\nrecord struct A\n{\n public static int field = 42;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyDiagnostics();\n var verifier = CompileAndVerify(comp);\n verifier.VerifyIL(\"A.Equals(A)\", @\"\n{\n // Code size 2 (0x2)\n .maxstack 1\n IL_0000: ldc.i4.1\n IL_0001: ret\n}\");\n\n verifier.VerifyIL(\"A.GetHashCode()\", @\"\n{\n // Code size 2 (0x2)\n .maxstack 1\n IL_0000: ldc.i4.0\n IL_0001: ret\n}\");\n }\n\n [Fact]\n public void RecordEquals_GeneratedAsReadOnly()\n {\n var src = @\"\nrecord struct A(int I, string S);\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n var recordEquals = comp.GetMembers(\"A.Equals\").OfType().Single();\n Assert.True(recordEquals.IsDeclaredReadOnly);\n }\n\n [Fact]\n public void ObjectEquals_06()\n {\n var source = @\"\nrecord struct A\n{\n public static new bool Equals(object obj) => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,28): error CS0111: Type 'A' already defines a member called 'Equals' with the same parameter types\n // public static new bool Equals(object obj) => throw null;\n Diagnostic(ErrorCode.ERR_MemberAlreadyExists, \"Equals\").WithArguments(\"Equals\", \"A\").WithLocation(4, 28)\n );\n }\n\n [Fact]\n public void ObjectEquals_UserDefined()\n {\n var source = @\"\nrecord struct A\n{\n public override bool Equals(object obj) => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,26): error CS0111: Type 'A' already defines a member called 'Equals' with the same parameter types\n // public override bool Equals(object obj) => throw null;\n Diagnostic(ErrorCode.ERR_MemberAlreadyExists, \"Equals\").WithArguments(\"Equals\", \"A\").WithLocation(4, 26)\n );\n }\n\n [Fact]\n public void ObjectEquals_GeneratedAsReadOnly()\n {\n var src = @\"\nrecord struct A(int I, string S);\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n var objectEquals = comp.GetMembers(\"A.Equals\").OfType().Single();\n Assert.True(objectEquals.IsDeclaredReadOnly);\n }\n\n [Fact]\n public void GetHashCode_UserDefined()\n {\n var source = @\"\nSystem.Console.Write(new A().GetHashCode());\n\nrecord struct A\n{\n public override int GetHashCode() => 42;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics();\n CompileAndVerify(comp, expectedOutput: \"42\");\n }\n\n [Fact]\n public void GetHashCode_GetHashCodeInValueType()\n {\n var src = @\"\npublic record struct A;\n\nnamespace System\n{\n public class Object\n {\n public virtual bool Equals(object x) => throw null;\n public virtual string ToString() => throw null;\n }\n public class Exception { }\n public class ValueType\n {\n public virtual int GetHashCode() => throw null;\n }\n public class Attribute { }\n public class String { }\n public struct Void { }\n public struct Boolean { }\n public struct Char { }\n public struct Int32 { }\n public interface IEquatable { }\n}\nnamespace System.Collections.Generic\n{\n public abstract class EqualityComparer\n {\n public static EqualityComparer Default => throw null;\n public abstract int GetHashCode(T t);\n }\n}\nnamespace System.Text\n{\n public class StringBuilder\n {\n public StringBuilder Append(string s) => null;\n public StringBuilder Append(char c) => null;\n public StringBuilder Append(object o) => null;\n }\n}\n\";\n var comp = CreateEmptyCompilation(src, parseOptions: TestOptions.RegularPreview);\n\n comp.VerifyEmitDiagnostics(\n // warning CS8021: No value for RuntimeMetadataVersion found. No assembly containing System.Object was found nor was a value for RuntimeMetadataVersion specified through options.\n Diagnostic(ErrorCode.WRN_NoRuntimeMetadataVersion).WithLocation(1, 1),\n // (2,22): error CS8869: 'A.GetHashCode()' does not override expected method from 'object'.\n // public record struct A;\n Diagnostic(ErrorCode.ERR_DoesNotOverrideMethodFromObject, \"A\").WithArguments(\"A.GetHashCode()\").WithLocation(2, 22)\n );\n }\n\n [Fact]\n public void GetHashCode_MissingEqualityComparer_EmptyRecord()\n {\n var src = @\"\npublic record struct A;\n\";\n var comp = CreateCompilation(src);\n comp.MakeTypeMissing(WellKnownType.System_Collections_Generic_EqualityComparer_T);\n comp.VerifyEmitDiagnostics();\n }\n\n [Fact]\n public void GetHashCode_MissingEqualityComparer_NonEmptyRecord()\n {\n var src = @\"\npublic record struct A(int I);\n\";\n var comp = CreateCompilation(src);\n comp.MakeTypeMissing(WellKnownType.System_Collections_Generic_EqualityComparer_T);\n\n comp.VerifyEmitDiagnostics(\n // (2,1): error CS0656: Missing compiler required member 'System.Collections.Generic.EqualityComparer`1.GetHashCode'\n // public record struct A(int I);\n Diagnostic(ErrorCode.ERR_MissingPredefinedMember, \"public record struct A(int I);\").WithArguments(\"System.Collections.Generic.EqualityComparer`1\", \"GetHashCode\").WithLocation(2, 1),\n // (2,1): error CS0656: Missing compiler required member 'System.Collections.Generic.EqualityComparer`1.get_Default'\n // public record struct A(int I);\n Diagnostic(ErrorCode.ERR_MissingPredefinedMember, \"public record struct A(int I);\").WithArguments(\"System.Collections.Generic.EqualityComparer`1\", \"get_Default\").WithLocation(2, 1)\n );\n }\n\n [Fact]\n public void GetHashCode_GeneratedAsReadOnly()\n {\n var src = @\"\nrecord struct A(int I, string S);\n\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n var method = comp.GetMember(\"A.GetHashCode\");\n Assert.True(method.IsDeclaredReadOnly);\n }\n\n [Fact]\n public void GetHashCodeIsDefinedButEqualsIsNot()\n {\n var src = @\"\npublic record struct C\n{\n public object Data;\n public override int GetHashCode() { return 0; }\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics();\n }\n\n [Fact]\n public void EqualsIsDefinedButGetHashCodeIsNot()\n {\n var src = @\"\npublic record struct C\n{\n public object Data;\n public bool Equals(C c) { return false; }\n}\";\n var comp = CreateCompilation(src);\n comp.VerifyDiagnostics(\n // (5,17): warning CS8851: 'C' defines 'Equals' but not 'GetHashCode'\n // public bool Equals(C c) { return false; }\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"C\").WithLocation(5, 17));\n }\n\n [Fact]\n public void EqualityOperators_01()\n {\n var source = @\"\nrecord struct A(int X)\n{\n public bool Equals(ref A other)\n => throw null;\n\n static void Main()\n {\n Test(default, default);\n Test(default, new A(0));\n Test(new A(1), new A(1));\n Test(new A(2), new A(3));\n var a = new A(11);\n Test(a, a);\n }\n\n static void Test(A a1, A a2)\n {\n System.Console.WriteLine(\"\"{0} {1} {2} {3}\"\", a1 == a2, a2 == a1, a1 != a2, a2 != a1);\n }\n}\n\";\n var verifier = CompileAndVerify(source, expectedOutput: @\"\nTrue True False False\nTrue True False False\nTrue True False False\nFalse False True True\nTrue True False False\n\").VerifyDiagnostics();\n\n var comp = (CSharpCompilation)verifier.Compilation;\n MethodSymbol op = comp.GetMembers(\"A.\" + WellKnownMemberNames.EqualityOperatorName).OfType().Single();\n Assert.Equal(\"System.Boolean A.op_Equality(A left, A right)\", op.ToTestDisplayString());\n Assert.Equal(Accessibility.Public, op.DeclaredAccessibility);\n Assert.True(op.IsStatic);\n Assert.False(op.IsAbstract);\n Assert.False(op.IsVirtual);\n Assert.False(op.IsOverride);\n Assert.False(op.IsSealed);\n Assert.True(op.IsImplicitlyDeclared);\n\n op = comp.GetMembers(\"A.\" + WellKnownMemberNames.InequalityOperatorName).OfType().Single();\n Assert.Equal(\"System.Boolean A.op_Inequality(A left, A right)\", op.ToTestDisplayString());\n Assert.Equal(Accessibility.Public, op.DeclaredAccessibility);\n Assert.True(op.IsStatic);\n Assert.False(op.IsAbstract);\n Assert.False(op.IsVirtual);\n Assert.False(op.IsOverride);\n Assert.False(op.IsSealed);\n Assert.True(op.IsImplicitlyDeclared);\n\n verifier.VerifyIL(\"bool A.op_Equality(A, A)\", @\"\n{\n // Code size 9 (0x9)\n .maxstack 2\n IL_0000: ldarga.s V_0\n IL_0002: ldarg.1\n IL_0003: call \"\"readonly bool A.Equals(A)\"\"\n IL_0008: ret\n}\n\");\n\n verifier.VerifyIL(\"bool A.op_Inequality(A, A)\", @\"\n{\n // Code size 11 (0xb)\n .maxstack 2\n IL_0000: ldarg.0\n IL_0001: ldarg.1\n IL_0002: call \"\"bool A.op_Equality(A, A)\"\"\n IL_0007: ldc.i4.0\n IL_0008: ceq\n IL_000a: ret\n}\n\");\n }\n\n [Fact]\n public void EqualityOperators_03()\n {\n var source =\n@\"\nrecord struct A\n{\n public static bool operator==(A r1, A r2)\n => throw null;\n public static bool operator==(A r1, string r2)\n => throw null;\n public static bool operator!=(A r1, string r2)\n => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,32): error CS0111: Type 'A' already defines a member called 'op_Equality' with the same parameter types\n // public static bool operator==(A r1, A r2)\n Diagnostic(ErrorCode.ERR_MemberAlreadyExists, \"==\").WithArguments(\"op_Equality\", \"A\").WithLocation(4, 32)\n );\n }\n\n [Fact]\n public void EqualityOperators_04()\n {\n var source = @\"\nrecord struct A\n{\n public static bool operator!=(A r1, A r2)\n => throw null;\n public static bool operator!=(string r1, A r2)\n => throw null;\n public static bool operator==(string r1, A r2)\n => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,32): error CS0111: Type 'A' already defines a member called 'op_Inequality' with the same parameter types\n // public static bool operator!=(A r1, A r2)\n Diagnostic(ErrorCode.ERR_MemberAlreadyExists, \"!=\").WithArguments(\"op_Inequality\", \"A\").WithLocation(4, 32)\n );\n }\n\n [Fact]\n public void EqualityOperators_05()\n {\n var source = @\"\nrecord struct A\n{\n public static bool op_Equality(A r1, A r2)\n => throw null;\n public static bool op_Equality(string r1, A r2)\n => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,24): error CS0111: Type 'A' already defines a member called 'op_Equality' with the same parameter types\n // public static bool op_Equality(A r1, A r2)\n Diagnostic(ErrorCode.ERR_MemberAlreadyExists, \"op_Equality\").WithArguments(\"op_Equality\", \"A\").WithLocation(4, 24)\n );\n }\n\n [Fact]\n public void EqualityOperators_06()\n {\n var source = @\"\nrecord struct A\n{\n public static bool op_Inequality(A r1, A r2)\n => throw null;\n public static bool op_Inequality(A r1, string r2)\n => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (4,24): error CS0111: Type 'A' already defines a member called 'op_Inequality' with the same parameter types\n // public static bool op_Inequality(A r1, A r2)\n Diagnostic(ErrorCode.ERR_MemberAlreadyExists, \"op_Inequality\").WithArguments(\"op_Inequality\", \"A\").WithLocation(4, 24)\n );\n }\n\n [Fact]\n public void EqualityOperators_07()\n {\n var source = @\"\nrecord struct A\n{\n public static bool Equals(A other)\n => throw null;\n}\n\";\n var comp = CreateCompilation(source);\n comp.VerifyEmitDiagnostics(\n // (2,15): error CS0736: 'A' does not implement interface member 'IEquatable.Equals(A)'. 'A.Equals(A)' cannot implement an interface member because it is static.\n // record struct A\n Diagnostic(ErrorCode.ERR_CloseUnimplementedInterfaceMemberStatic, \"A\").WithArguments(\"A\", \"System.IEquatable.Equals(A)\", \"A.Equals(A)\").WithLocation(2, 15),\n // (4,24): error CS8877: Record member 'A.Equals(A)' may not be static.\n // public static bool Equals(A other)\n Diagnostic(ErrorCode.ERR_StaticAPIInRecord, \"Equals\").WithArguments(\"A.Equals(A)\").WithLocation(4, 24),\n // (4,24): warning CS8851: 'A' defines 'Equals' but not 'GetHashCode'\n // public static bool Equals(A other)\n Diagnostic(ErrorCode.WRN_RecordEqualsWithoutGetHashCode, \"Equals\").WithArguments(\"A\").WithLocation(4, 24)\n );\n }\n\n [Theory]\n [CombinatorialData]\n public void EqualityOperators_09(bool useImageReference)\n {\n var source1 = @\"\npublic record struct A(int X);\n\";\n var comp1 = CreateCompilation(source1);\n\n var source2 =\n@\"\nclass Program\n{\n static void Main()\n {\n Test(default, default);\n Test(default, new A(0));\n Test(new A(1), new A(1));\n Test(new A(2), new A(3));\n }\n\n static void Test(A a1, A a2)\n {\n System.Console.WriteLine(\"\"{0} {1} {2} {3}\"\", a1 == a2, a2 == a1, a1 != a2, a2 != a1);\n }\n}\n\";\n CompileAndVerify(source2, references: new[] { useImageReference ? comp1.EmitToImageReference() : comp1.ToMetadataReference() }, expectedOutput: @\"\nTrue True False False\nTrue True False False\nTrue True False False\nFalse False True True\n\").VerifyDiagnostics();\n }\n\n [Fact]\n public void GetSimpleNonTypeMembers_DirectApiCheck()\n {\n var src = @\"\npublic record struct RecordB();\n\";\n var comp = CreateCompilation(src);\n var b = comp.GlobalNamespace.GetTypeMember(\"RecordB\");\n AssertEx.SetEqual(new[] { \"System.Boolean RecordB.op_Equality(RecordB left, RecordB right)\" },\n b.GetSimpleNonTypeMembers(\"op_Equality\").ToTestDisplayStrings());\n }\n\n [Fact]\n public void ToString_NestedRecord()\n {\n var src = @\"\nvar c1 = new Outer.C1(42);\nSystem.Console.Write(c1.ToString());\n\npublic class Outer\n{\n public record struct C1(int I1);\n}\n\";\n\n var compDebug = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.DebugExe);\n var compRelease = CreateCompilation(new[] { src, IsExternalInitTypeDefinition }, parseOptions: TestOptions.RegularPreview, options: TestOptions.ReleaseExe);\n CompileAndVerify(compDebug, expectedOutput: \"C1 { I1 = 42 }\");\n compDebug.VerifyEmitDiagnostics();\n\n CompileAndVerify(compRelease, expectedOutput: \"C1 { I1 = 42 }\");\n compRelease.VerifyEmitDiagnostics();\n }\n\n [Fact]\n public void ToString_TopLevelRecord_Empty()\n {\n var src = @\"\nvar c1 = new C1();\nSystem.Console.Write(c1.ToString());\n\nrecord struct C1;\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics();\n var v = CompileAndVerify(comp, expectedOutput: \"C1 { }\");\n\n var print = comp.GetMember(\"C1.\" + WellKnownMemberNames.PrintMembersMethodName);\n Assert.Equal(Accessibility.Private, print.DeclaredAccessibility);\n Assert.False(print.IsOverride);\n Assert.False(print.IsVirtual);\n Assert.False(print.IsAbstract);\n Assert.False(print.IsSealed);\n Assert.True(print.IsImplicitlyDeclared);\n\n var toString = comp.GetMember(\"C1.\" + WellKnownMemberNames.ObjectToString);\n Assert.Equal(Accessibility.Public, toString.DeclaredAccessibility);\n Assert.True(toString.IsOverride);\n Assert.False(toString.IsVirtual);\n Assert.False(toString.IsAbstract);\n Assert.False(toString.IsSealed);\n Assert.True(toString.IsImplicitlyDeclared);\n\n v.VerifyIL(\"C1.\" + WellKnownMemberNames.PrintMembersMethodName, @\"\n{\n // Code size 2 (0x2)\n .maxstack 1\n IL_0000: ldc.i4.0\n IL_0001: ret\n}\n\");\n v.VerifyIL(\"C1.\" + WellKnownMemberNames.ObjectToString, @\"\n{\n // Code size 64 (0x40)\n .maxstack 2\n .locals init (System.Text.StringBuilder V_0)\n IL_0000: newobj \"\"System.Text.StringBuilder..ctor()\"\"\n IL_0005: stloc.0\n IL_0006: ldloc.0\n IL_0007: ldstr \"\"C1\"\"\n IL_000c: callvirt \"\"System.Text.StringBuilder System.Text.StringBuilder.Append(string)\"\"\n IL_0011: pop\n IL_0012: ldloc.0\n IL_0013: ldstr \"\" { \"\"\n IL_0018: callvirt \"\"System.Text.StringBuilder System.Text.StringBuilder.Append(string)\"\"\n IL_001d: pop\n IL_001e: ldarg.0\n IL_001f: ldloc.0\n IL_0020: call \"\"readonly bool C1.PrintMembers(System.Text.StringBuilder)\"\"\n IL_0025: brfalse.s IL_0030\n IL_0027: ldloc.0\n IL_0028: ldc.i4.s 32\n IL_002a: callvirt \"\"System.Text.StringBuilder System.Text.StringBuilder.Append(char)\"\"\n IL_002f: pop\n IL_0030: ldloc.0\n IL_0031: ldc.i4.s 125\n IL_0033: callvirt \"\"System.Text.StringBuilder System.Text.StringBuilder.Append(char)\"\"\n IL_0038: pop\n IL_0039: ldloc.0\n IL_003a: callvirt \"\"string object.ToString()\"\"\n IL_003f: ret\n}\n\");\n }\n\n [Fact]\n public void ToString_TopLevelRecord_MissingStringBuilder()\n {\n var src = @\"\nrecord struct C1;\n\";\n\n var comp = CreateCompilation(src);\n comp.MakeTypeMissing(WellKnownType.System_Text_StringBuilder);\n comp.VerifyEmitDiagnostics(\n // (2,1): error CS0518: Predefined type 'System.Text.StringBuilder' is not defined or imported\n // record struct C1;\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"record struct C1;\").WithArguments(\"System.Text.StringBuilder\").WithLocation(2, 1),\n // (2,1): error CS0656: Missing compiler required member 'System.Text.StringBuilder..ctor'\n // record struct C1;\n Diagnostic(ErrorCode.ERR_MissingPredefinedMember, \"record struct C1;\").WithArguments(\"System.Text.StringBuilder\", \".ctor\").WithLocation(2, 1),\n // (2,15): error CS0518: Predefined type 'System.Text.StringBuilder' is not defined or imported\n // record struct C1;\n Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, \"C1\").WithArguments(\"System.Text.StringBuilder\").WithLocation(2, 15)\n );\n }\n\n [Fact]\n public void ToString_TopLevelRecord_MissingStringBuilderCtor()\n {\n var src = @\"\nrecord struct C1;\n\";\n\n var comp = CreateCompilation(src);\n comp.MakeMemberMissing(WellKnownMember.System_Text_StringBuilder__ctor);\n comp.VerifyEmitDiagnostics(\n // (2,1): error CS0656: Missing compiler required member 'System.Text.StringBuilder..ctor'\n // record struct C1;\n Diagnostic(ErrorCode.ERR_MissingPredefinedMember, \"record struct C1;\").WithArguments(\"System.Text.StringBuilder\", \".ctor\").WithLocation(2, 1)\n );\n }\n\n [Fact]\n public void ToString_TopLevelRecord_MissingStringBuilderAppendString()\n {\n var src = @\"\nrecord struct C1;\n\";\n\n var comp = CreateCompilation(src);\n comp.MakeMemberMissing(WellKnownMember.System_Text_StringBuilder__AppendString);\n comp.VerifyEmitDiagnostics(\n // (2,1): error CS0656: Missing compiler required member 'System.Text.StringBuilder.Append'\n // record struct C1;\n Diagnostic(ErrorCode.ERR_MissingPredefinedMember, \"record struct C1;\").WithArguments(\"System.Text.StringBuilder\", \"Append\").WithLocation(2, 1)\n );\n }\n\n [Fact]\n public void ToString_TopLevelRecord_OneProperty_MissingStringBuilderAppendString()\n {\n var src = @\"\nrecord struct C1(int P);\n\";\n\n var comp = CreateCompilation(src);\n comp.MakeMemberMissing(WellKnownMember.System_Text_StringBuilder__AppendString);\n comp.VerifyEmitDiagnostics(\n // (2,1): error CS0656: Missing compiler required member 'System.Text.StringBuilder.Append'\n // record struct C1(int P);\n Diagnostic(ErrorCode.ERR_MissingPredefinedMember, \"record struct C1(int P);\").WithArguments(\"System.Text.StringBuilder\", \"Append\").WithLocation(2, 1),\n // (2,1): error CS0656: Missing compiler required member 'System.Text.StringBuilder.Append'\n // record struct C1(int P);\n Diagnostic(ErrorCode.ERR_MissingPredefinedMember, \"record struct C1(int P);\").WithArguments(\"System.Text.StringBuilder\", \"Append\").WithLocation(2, 1)\n );\n }\n\n [Fact]\n public void ToString_RecordWithIndexer()\n {\n var src = @\"\nvar c1 = new C1(42);\nSystem.Console.Write(c1.ToString());\n\nrecord struct C1(int I1)\n{\n private int field = 44;\n public int this[int i] => 0;\n public int PropertyWithoutGetter { set { } }\n public int P2 { get => 43; }\n public event System.Action a = null;\n\n private int field1 = 100;\n internal int field2 = 100;\n\n private int Property1 { get; set; } = 100;\n internal int Property2 { get; set; } = 100;\n}\n\";\n\n var comp = CreateCompilation(src);\n CompileAndVerify(comp, expectedOutput: \"C1 { I1 = 42, P2 = 43 }\");\n comp.VerifyEmitDiagnostics(\n // (7,17): warning CS0414: The field 'C1.field' is assigned but its value is never used\n // private int field = 44;\n Diagnostic(ErrorCode.WRN_UnreferencedFieldAssg, \"field\").WithArguments(\"C1.field\").WithLocation(7, 17),\n // (11,32): warning CS0414: The field 'C1.a' is assigned but its value is never used\n // public event System.Action a = null;\n Diagnostic(ErrorCode.WRN_UnreferencedFieldAssg, \"a\").WithArguments(\"C1.a\").WithLocation(11, 32),\n // (13,17): warning CS0414: The field 'C1.field1' is assigned but its value is never used\n // private int field1 = 100;\n Diagnostic(ErrorCode.WRN_UnreferencedFieldAssg, \"field1\").WithArguments(\"C1.field1\").WithLocation(13, 17)\n );\n }\n\n [Fact]\n public void ToString_PrivateGetter()\n {\n var src = @\"\nvar c1 = new C1();\nSystem.Console.Write(c1.ToString());\n\nrecord struct C1\n{\n public int P1 { private get => 43; set => throw null; }\n}\n\";\n\n var comp = CreateCompilation(src);\n CompileAndVerify(comp, expectedOutput: \"C1 { P1 = 43 }\");\n comp.VerifyEmitDiagnostics();\n }\n\n [Fact]\n public void ToString_TopLevelRecord_OneField_ValueType()\n {\n var src = @\"\nvar c1 = new C1() { field = 42 };\nSystem.Console.Write(c1.ToString());\n\nrecord struct C1\n{\n public int field;\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics();\n var v = CompileAndVerify(comp, expectedOutput: \"C1 { field = 42 }\");\n\n var print = comp.GetMember(\"C1.\" + WellKnownMemberNames.PrintMembersMethodName);\n Assert.Equal(Accessibility.Private, print.DeclaredAccessibility);\n Assert.False(print.IsOverride);\n Assert.False(print.IsVirtual);\n Assert.False(print.IsAbstract);\n Assert.False(print.IsSealed);\n Assert.True(print.IsImplicitlyDeclared);\n\n var toString = comp.GetMember(\"C1.\" + WellKnownMemberNames.ObjectToString);\n Assert.Equal(Accessibility.Public, toString.DeclaredAccessibility);\n Assert.True(toString.IsOverride);\n Assert.False(toString.IsVirtual);\n Assert.False(toString.IsAbstract);\n Assert.False(toString.IsSealed);\n Assert.True(toString.IsImplicitlyDeclared);\n\n v.VerifyIL(\"C1.\" + WellKnownMemberNames.PrintMembersMethodName, @\"\n{\n // Code size 38 (0x26)\n .maxstack 2\n IL_0000: ldarg.1\n IL_0001: ldstr \"\"field = \"\"\n IL_0006: callvirt \"\"System.Text.StringBuilder System.Text.StringBuilder.Append(string)\"\"\n IL_000b: pop\n IL_000c: ldarg.1\n IL_000d: ldarg.0\n IL_000e: ldflda \"\"int C1.field\"\"\n IL_0013: constrained. \"\"int\"\"\n IL_0019: callvirt \"\"string object.ToString()\"\"\n IL_001e: callvirt \"\"System.Text.StringBuilder System.Text.StringBuilder.Append(string)\"\"\n IL_0023: pop\n IL_0024: ldc.i4.1\n IL_0025: ret\n}\n\");\n }\n\n [Fact]\n public void ToString_TopLevelRecord_OneField_ConstrainedValueType()\n {\n var src = @\"\nvar c1 = new C1() { field = 42 };\nSystem.Console.Write(c1.ToString());\n\nrecord struct C1 where T : struct\n{\n public T field;\n}\n\";\n\n var comp = CreateCompilation(src);\n comp.VerifyEmitDiagnostics();\n var v = CompileAndVerify(comp, expectedOutput: \"C1 { field = 42 }\");\n\n v.VerifyIL(\"C1.\" + WellKnownMemberNames.PrintMembersMethodName, @\"\n{\n // Code size 41 (0x29)\n .maxstack 2\n .locals init (T V_0)\n IL_0000: ldarg.1\n IL_0001: ldstr \"\"field = \"\"\n IL_0006: callvirt \"\"System.Text.StringBuilder System.Text.StringBuilder.Append(string)\"\"\n IL_000b: pop\n IL_000c: ldarg.1\n IL_000d: ldarg.0\n IL_000e: ldfld \"\"T C1