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merged 3 commits into from
Nov 7, 2025
Merged

Use standard overload resolution for true/false operators while binding applications of dynamic &&/|| operators #81055

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bb76fce
Use standard overload resolution for `true`/`false` operators while b…
AlekseyTs Nov 5, 2025
f7268d6
Merge remote-tracking branch 'upstream/main' into Issue78602_2
AlekseyTs Nov 5, 2025
b05146f
Fixup after merge from main
AlekseyTs Nov 5, 2025
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63 changes: 21 additions & 42 deletions src/Compilers/CSharp/Portable/Binder/Binder_Operators.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1619,8 +1619,7 @@ private bool IsValidDynamicCondition(BoundExpression left, bool isNegative, Bind
{
if (left.Type is not null)
{
var operandPlaceholder = new BoundValuePlaceholder(left.Syntax, left.Type).MakeCompilerGenerated();
CreateConversion(left.Syntax, operandPlaceholder, implicitConversion, isCast: false, conversionGroupOpt: null, booleanType, diagnostics);
CreateConversion(left.Syntax, new BoundValuePlaceholder(left.Syntax, left.Type).MakeCompilerGenerated(), implicitConversion, isCast: false, conversionGroupOpt: null, booleanType, diagnostics);
}
else
{
Expand All @@ -1631,7 +1630,7 @@ private bool IsValidDynamicCondition(BoundExpression left, bool isNegative, Bind
return true;
}

if (type.Kind != SymbolKind.NamedType)
if (type.Kind != SymbolKind.NamedType || type.IsNullableType())
{
diagnostics.Add(left.Syntax, useSiteInfo);
return false;
Expand All @@ -1651,52 +1650,32 @@ private bool IsValidDynamicCondition(BoundExpression left, bool isNegative, Bind
// at CallSite.Target(Closure, CallSite, Object, Nullable`1)
// at System.Dynamic.UpdateDelegates.UpdateAndExecute2[T0,T1,TRet](CallSite site, T0 arg0, T1 arg1)
var namedType = type as NamedTypeSymbol;
var result = hasApplicableBooleanOperator(namedType, isNegative ? WellKnownMemberNames.FalseOperatorName : WellKnownMemberNames.TrueOperatorName, type, ref useSiteInfo, out userDefinedOperator);
var operandPlaceholder = new BoundValuePlaceholder(left.Syntax, namedType).MakeCompilerGenerated();
UnaryOperatorAnalysisResult result = operatorOverloadResolution(left.Syntax, operandPlaceholder, isNegative ? UnaryOperatorKind.False : UnaryOperatorKind.True, diagnostics);

if (result)
if (result.HasValue)
{
Debug.Assert(userDefinedOperator is not null);
Debug.Assert(result.Conversion.IsImplicit);
userDefinedOperator = result.Signature.Method;

var operandPlaceholder = new BoundValuePlaceholder(left.Syntax, left.Type).MakeCompilerGenerated();
TypeSymbol parameterType = userDefinedOperator.Parameters[0].Type;

implicitConversion = this.Conversions.ClassifyConversionFromType(operandPlaceholder.Type, parameterType, isChecked: CheckOverflowAtRuntime, ref useSiteInfo);
Debug.Assert(implicitConversion.IsImplicit);

CreateConversion(left.Syntax, operandPlaceholder, implicitConversion, isCast: false, conversionGroupOpt: null, parameterType, diagnostics);
CreateConversion(left.Syntax, operandPlaceholder, result.Conversion, isCast: false, conversionGroupOpt: null, parameterType, diagnostics);
return true;
}

diagnostics.Add(left.Syntax, useSiteInfo);

return result;
return false;

bool hasApplicableBooleanOperator(NamedTypeSymbol containingType, string name, TypeSymbol argumentType, ref CompoundUseSiteInfo<AssemblySymbol> useSiteInfo, out MethodSymbol @operator)
UnaryOperatorAnalysisResult operatorOverloadResolution(SyntaxNode node, BoundExpression operand, UnaryOperatorKind kind, BindingDiagnosticBag diagnostics)
{
var operators = ArrayBuilder<MethodSymbol>.GetInstance();
for (var type = containingType; (object)type != null; type = type.BaseTypeWithDefinitionUseSiteDiagnostics(ref useSiteInfo))
{
operators.Clear();
type.AddOperators(name, operators);
OverloadResolution.GetStaticUserDefinedUnaryOperatorMethodNames(kind, isChecked: false, out string staticOperatorName1, out string staticOperatorName2Opt);

for (var i = 0; i < operators.Count; i++)
{
var op = operators[i];
if (op.ParameterCount == 1 && op.DeclaredAccessibility == Accessibility.Public)
{
var conversion = this.Conversions.ClassifyConversionFromType(argumentType, op.GetParameterType(0), isChecked: CheckOverflowAtRuntime, ref useSiteInfo);
if (conversion.IsImplicit)
{
@operator = op;
operators.Free();
return true;
}
}
}
}
OperatorResolutionForReporting operatorResolutionForReporting = default;
var result = this.UnaryOperatorNonExtensionOverloadResolution(
kind, isChecked: false, staticOperatorName1, staticOperatorName2Opt,
operand: operand, node, diagnostics, ref operatorResolutionForReporting, resultKind: out _, originalUserDefinedOperators: out _);
operatorResolutionForReporting.Free();

operators.Free();
@operator = null;
return false;
return result;
}
}

Expand Down Expand Up @@ -2245,7 +2224,7 @@ private static BinaryOperatorAnalysisResult BinaryOperatorAnalyzeOverloadResolut
return possiblyBest;
}

private void ReportObsoleteAndFeatureAvailabilityDiagnostics(MethodSymbol operatorMethod, CSharpSyntaxNode node, BindingDiagnosticBag diagnostics)
private void ReportObsoleteAndFeatureAvailabilityDiagnostics(MethodSymbol operatorMethod, SyntaxNode node, BindingDiagnosticBag diagnostics)
{
if ((object)operatorMethod != null)
{
Expand Down Expand Up @@ -2326,7 +2305,7 @@ private UnaryOperatorAnalysisResult UnaryOperatorNonExtensionOverloadResolution(
string name1,
string name2Opt,
BoundExpression operand,
CSharpSyntaxNode node,
SyntaxNode node,
BindingDiagnosticBag diagnostics,
ref OperatorResolutionForReporting operatorResolutionForReporting,
out LookupResultKind resultKind,
Expand Down Expand Up @@ -2355,7 +2334,7 @@ UnaryOperatorAnalysisResult AnalyzeUnaryOperatorOverloadResolutionResult(
UnaryOperatorOverloadResolutionResult result,
UnaryOperatorKind kind,
BoundExpression operand,
CSharpSyntaxNode node,
SyntaxNode node,
BindingDiagnosticBag diagnostics,
out LookupResultKind resultKind,
out ImmutableArray<MethodSymbol> originalUserDefinedOperators)
Expand Down
158 changes: 158 additions & 0 deletions src/Compilers/CSharp/Test/Semantic/Semantics/OperatorTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -9755,6 +9755,164 @@ public static bool operator false(S2 x)
CompileAndVerify(comp, expectedOutput: "4343").VerifyDiagnostics();
}

[Fact]
[WorkItem("https://github.com/dotnet/roslyn/issues/78602")]
public void UserDefinedShortCircuitingOperators_TrueFalseIsOverloaded_Dynamic_01()
{
var src = $$$"""
public class Program
{
static void Main()
{
var x1 = new S1();
dynamic y1 = new S1();

_ = x1 && y1;
_ = x1 || y1;

var x2 = new S2();
dynamic y2 = new S2();

_ = x2 && y2;
_ = x2 || y2;
}
}

struct S1 // nullable operators come first
{
public static S1 operator &(S1 x, S1 y) => x;
public static S1 operator |(S1 x, S1 y) => x;

public static bool operator true(S1? x) => throw null;
public static bool operator false(S1? x) => throw null;

public static bool operator true(S1 x)
{
System.Console.Write(3);
return false;
}
public static bool operator false(S1 x)
{
System.Console.Write(4);
return false;
}
}

struct S2 // non-nullable operators come first
{
public static S2 operator &(S2 x, S2 y) => x;
public static S2 operator |(S2 x, S2 y) => x;
public static bool operator true(S2 x)
{
System.Console.Write(3);
return false;
}
public static bool operator false(S2 x)
{
System.Console.Write(4);
return false;
}

public static bool operator true(S2? x) => throw null;
public static bool operator false(S2? x) => throw null;
}
""";

var comp = CreateCompilation(src, targetFramework: TargetFramework.StandardAndCSharp, options: TestOptions.DebugExe);
CompileAndVerify(comp, expectedOutput: "44334433").VerifyDiagnostics();
}

[Fact]
[WorkItem("https://github.com/dotnet/roslyn/issues/78602")]
public void UserDefinedShortCircuitingOperators_TrueFalseIsOverloaded_Dynamic_02()
{
var src = $$$"""
public class Program
{
static void Main()
{
var x1 = new S1();
dynamic y1 = new S1();

_ = x1 && y1;
_ = x1 || y1;

var x2 = new S2();
dynamic y2 = new S2();

_ = x2 && y2;
_ = x2 || y2;
}
}

struct S1 {}
struct S2 {}

static class Extensions
{
extension(S1?) // nullable operators come first
{
public static bool operator true(S1? x) => throw null;
public static bool operator false(S1? x) => throw null;
}

extension(S1)
{
public static S1 operator &(S1 x, S1 y) => x;
public static S1 operator |(S1 x, S1 y) => x;
public static bool operator true(S1 x)
{
System.Console.Write(3);
return false;
}
public static bool operator false(S1 x)
{
System.Console.Write(4);
return false;
}
}

extension(S2) // non-nullable operators come first
{
public static S2 operator &(S2 x, S2 y) => x;
public static S2 operator |(S2 x, S2 y) => x;
public static bool operator true(S2 x)
{
System.Console.Write(3);
return false;
}
public static bool operator false(S2 x)
{
System.Console.Write(4);
return false;
}
}

extension(S2?)
{
public static bool operator true(S2? x) => throw null;
public static bool operator false(S2? x) => throw null;
}
}
""";

var comp = CreateCompilation(src, options: TestOptions.DebugExe);
comp.VerifyDiagnostics(
// (8,13): error CS7083: Expression must be implicitly convertible to Boolean or its type 'S1' must define operator 'false'.
// _ = x1 && y1;
Diagnostic(ErrorCode.ERR_InvalidDynamicCondition, "x1").WithArguments("S1", "false").WithLocation(8, 13),
// (9,13): error CS7083: Expression must be implicitly convertible to Boolean or its type 'S1' must define operator 'true'.
// _ = x1 || y1;
Diagnostic(ErrorCode.ERR_InvalidDynamicCondition, "x1").WithArguments("S1", "true").WithLocation(9, 13),
// (14,13): error CS7083: Expression must be implicitly convertible to Boolean or its type 'S2' must define operator 'false'.
// _ = x2 && y2;
Diagnostic(ErrorCode.ERR_InvalidDynamicCondition, "x2").WithArguments("S2", "false").WithLocation(14, 13),
// (15,13): error CS7083: Expression must be implicitly convertible to Boolean or its type 'S2' must define operator 'true'.
// _ = x2 || y2;
Diagnostic(ErrorCode.ERR_InvalidDynamicCondition, "x2").WithArguments("S2", "true").WithLocation(15, 13)
);
}

[Fact]
[WorkItem("https://github.com/dotnet/roslyn/issues/78617")]
public void UserDefinedShortCircuitingOperators_TrueFalseInBaseInterface_01()
Expand Down
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