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merged 2 commits into from
Aug 19, 2025
Merged

Add tests for field keyword semantic model and IOperation #79945

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ac9d893
Add tests for field keyword semantic model and IOperation
RikkiGibson Aug 18, 2025
1709066
Add analyzer test
RikkiGibson Aug 18, 2025
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150 changes: 150 additions & 0 deletions src/Compilers/CSharp/Test/Emit3/FieldKeywordTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Operations;
using Microsoft.CodeAnalysis.Test.Utilities;
using Roslyn.Test.Utilities;
using System.Collections.Immutable;
Expand Down Expand Up @@ -12710,5 +12711,154 @@ public partial class Class1
var comp = CreateCompilation([source1, source2]);
comp.VerifyEmitDiagnostics();
}

[Theory, WorkItem("https://github.com/dotnet/roslyn/issues/79201")]
[InlineData("""get { return field + "a"; }""")]
[InlineData("""get => field + "a";""")]
public void PublicAPI_01(string accessor)
{
var source = $$"""
class C
{
public string Prop
{
{{accessor}}
}
}
""";

var comp = CreateCompilation(source);
comp.VerifyEmitDiagnostics();

var tree = comp.SyntaxTrees[0];
var model = comp.GetSemanticModel(tree);
var fieldExpression = tree.GetRoot().DescendantNodes().OfType<FieldExpressionSyntax>().Single();

var symbolInfo = model.GetSymbolInfo(fieldExpression);
Assert.Equal("System.String C.<Prop>k__BackingField", symbolInfo.Symbol.ToTestDisplayString());
}

[Theory, WorkItem("https://github.com/dotnet/roslyn/issues/79201")]
[InlineData("""set { field = value; }""")]
[InlineData("""set => field = value;""")]
public void PublicAPI_02(string accessor)
{
var source = $$"""
class C
{
public string Prop
{
{{accessor}}
}
}
""";

var comp = CreateCompilation(source);
comp.VerifyEmitDiagnostics();

var tree = comp.SyntaxTrees[0];
var model = comp.GetSemanticModel(tree);
var fieldExpression = tree.GetRoot().DescendantNodes().OfType<FieldExpressionSyntax>().Single();

var symbolInfo = model.GetSymbolInfo(fieldExpression);
Assert.Equal("System.String C.<Prop>k__BackingField", symbolInfo.Symbol.ToTestDisplayString());
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/79201")]
public void PublicAPI_03()
{
var source = $$"""
class C
{
public string Prop
{
get => field;
}
}
""";

var comp = CreateCompilation(source, parseOptions: TestOptions.Regular13);
comp.VerifyEmitDiagnostics(
// (5,16): error CS0103: The name 'field' does not exist in the current context
// get => field;
Diagnostic(ErrorCode.ERR_NameNotInContext, "field").WithArguments("field").WithLocation(5, 16));

var tree = comp.SyntaxTrees[0];
var model = comp.GetSemanticModel(tree);
Assert.Empty(tree.GetRoot().DescendantNodes().OfType<FieldExpressionSyntax>());
var fieldExpression = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(node => node.ToString() == "field").Single();
var symbolInfo = model.GetSymbolInfo(fieldExpression);
Assert.Null(symbolInfo.Symbol);
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/79201")]
public void PublicAPI_04()
{
var source = $$"""
class C
{
public string Prop
{
get => field;
}
}
""";

var comp = CreateCompilation(source);
comp.VerifyEmitDiagnostics();
comp.VerifyAnalyzerDiagnostics(analyzers: [new TestAnalyzer1()],
expected: [Diagnostic("TEST_Field", "field").WithLocation(5, 16)]);

comp = CreateCompilation(source, parseOptions: TestOptions.Regular13);
comp.VerifyEmitDiagnostics(
// (5,16): error CS0103: The name 'field' does not exist in the current context
// get => field;
Diagnostic(ErrorCode.ERR_NameNotInContext, "field").WithArguments("field").WithLocation(5, 16));
comp.VerifyAnalyzerDiagnostics(analyzers: [new TestAnalyzer1()],
expected: [Diagnostic("TEST_Invalid", "field").WithLocation(5, 16)]);
}

private class TestAnalyzer1 : DiagnosticAnalyzer
{
public static readonly DiagnosticDescriptor Descriptor_Field = new(id: "TEST_Field", title: "Test", messageFormat: "", category: "", DiagnosticSeverity.Warning, isEnabledByDefault: true);
public static readonly DiagnosticDescriptor Descriptor_Invalid = new(id: "TEST_Invalid", title: "Test", messageFormat: "", category: "", DiagnosticSeverity.Warning, isEnabledByDefault: true);
public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => [Descriptor_Field, Descriptor_Invalid];

public override void Initialize(AnalysisContext context)
{
context.RegisterOperationBlockAction(context =>
{
foreach (var block in context.OperationBlocks)
{
var walker = new OperationWalker1();
walker.Visit(block);

if (walker.FieldReference is not null)
context.ReportDiagnostic(CodeAnalysis.Diagnostic.Create(Descriptor_Field, walker.FieldReference.Syntax.Location));

if (walker.Invalid is not null)
context.ReportDiagnostic(CodeAnalysis.Diagnostic.Create(Descriptor_Invalid, walker.Invalid.Syntax.Location));
}
});
}
}

private class OperationWalker1 : OperationWalker
{
public IOperation FieldReference = null;
public IOperation Invalid = null;

public override void VisitFieldReference(IFieldReferenceOperation operation)
{
FieldReference = operation;
base.VisitFieldReference(operation);
}

public override void VisitInvalid(IInvalidOperation operation)
{
Invalid = operation;
base.VisitInvalid(operation);
}
}
}
}
108 changes: 108 additions & 0 deletions src/Compilers/CSharp/Test/IOperation/IOperation/IOperationTests_IFieldReferenceExpression.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -715,5 +715,113 @@ static void testCore(CSharpCompilation comp)
Assert.Equal(fieldSym.GetHashCode(), fieldReferenceOperation.Field.GetHashCode());
}
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/79201")]
public void FieldKeyword_01()
{
var source = """
class C
{
public string Prop
{
get
{
/*<bind>*/
return field + "a";
/*</bind>*/
}
}
}
""";

VerifyOperationTreeAndDiagnosticsForTest<StatementSyntax>(
source,
expectedOperationTree: """
IReturnOperation (OperationKind.Return, Type: null) (Syntax: 'return field + "a";')
ReturnedValue:
IBinaryOperation (BinaryOperatorKind.Add) (OperationKind.Binary, Type: System.String) (Syntax: 'field + "a"')
Left:
IFieldReferenceOperation: System.String C.<Prop>k__BackingField (OperationKind.FieldReference, Type: System.String) (Syntax: 'field')
Instance Receiver:
IInstanceReferenceOperation (ReferenceKind: ContainingTypeInstance) (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'field')
Right:
ILiteralOperation (OperationKind.Literal, Type: System.String, Constant: "a") (Syntax: '"a"')
""",
expectedDiagnostics: []);
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/79201")]
public void FieldKeyword_02()
{
var source = """
class C
{
public string Prop
{
set
{
/*<bind>*/
field = value;
/*</bind>*/
}
}
}
""";

VerifyOperationTreeAndDiagnosticsForTest<StatementSyntax>(
source,
expectedOperationTree: """
IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'field = value;')
Expression:
ISimpleAssignmentOperation (OperationKind.SimpleAssignment, Type: System.String) (Syntax: 'field = value')
Left:
IFieldReferenceOperation: System.String C.<Prop>k__BackingField (OperationKind.FieldReference, Type: System.String) (Syntax: 'field')
Instance Receiver:
IInstanceReferenceOperation (ReferenceKind: ContainingTypeInstance) (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'field')
Right:
IParameterReferenceOperation: value (OperationKind.ParameterReference, Type: System.String) (Syntax: 'value')
""",
expectedDiagnostics: []);
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/79201")]
public void FieldKeyword_03()
{
var source = """
class C
{
public string Prop
{
get
{
/*<bind>*/
return field + "a";
/*</bind>*/
}
}
}
""";

VerifyOperationTreeAndDiagnosticsForTest<StatementSyntax>(
source,
expectedOperationTree: """
IReturnOperation (OperationKind.Return, Type: null, IsInvalid) (Syntax: 'return field + "a";')
ReturnedValue:
IConversionOperation (TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.String, IsInvalid, IsImplicit) (Syntax: 'field + "a"')
Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
Operand:
IBinaryOperation (BinaryOperatorKind.Add) (OperationKind.Binary, Type: ?, IsInvalid) (Syntax: 'field + "a"')
Left:
IInvalidOperation (OperationKind.Invalid, Type: ?, IsInvalid) (Syntax: 'field')
Children(0)
Right:
ILiteralOperation (OperationKind.Literal, Type: System.String, Constant: "a") (Syntax: '"a"')
""",
expectedDiagnostics: [
// (8,20): error CS0103: The name 'field' does not exist in the current context
// return field + "a";
Diagnostic(ErrorCode.ERR_NameNotInContext, "field").WithArguments("field").WithLocation(8, 20)],
parseOptions: TestOptions.Regular13);
}
}
}
2 changes: 1 addition & 1 deletion src/Compilers/Test/Utilities/CSharp/CSharpTestBase.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2613,7 +2613,7 @@ protected static void VerifyFlowGraphForTest<TSyntaxNode>(CSharpCompilation comp
{
var tree = compilation.SyntaxTrees[0];
SyntaxNode? syntaxNode = GetSyntaxNodeOfTypeForBinding<TSyntaxNode>(GetSyntaxNodeList(tree));
Debug.Assert(syntaxNode is not null, "Did you forget to place /*<bind>*/ comments in your source?");
Debug.Assert(syntaxNode is not null, $"Ensure a /*<bind>*/ comment is used around syntax matching the type argument for '{nameof(TSyntaxNode)}'.");
VerifyFlowGraph(compilation, syntaxNode, expectedFlowGraph);
}

Expand Down