/// <summary>
/// Bind and return a single type parameter constraint clause.
/// </summary>
private TypeParameterConstraintClause BindTypeParameterConstraints(TypeParameterSyntax typeParameterSyntax, TypeParameterConstraintClauseSyntax constraintClauseSyntax, DiagnosticBag diagnostics)
{
var constraints = TypeParameterConstraintKind.None;
var constraintTypes = ArrayBuilder <TypeWithAnnotations> .GetInstance();
var syntaxBuilder = ArrayBuilder <TypeConstraintSyntax> .GetInstance();
SeparatedSyntaxList <TypeParameterConstraintSyntax> constraintsSyntax = constraintClauseSyntax.Constraints;
Debug.Assert(!InExecutableBinder); // Cannot eagerly report diagnostics handled by LazyMissingNonNullTypesContextDiagnosticInfo
bool hasTypeLikeConstraint = false;
for (int i = 0, n = constraintsSyntax.Count; i < n; i++)
{
var syntax = constraintsSyntax[i];
switch (syntax.Kind())
{
case SyntaxKind.ClassConstraint:
hasTypeLikeConstraint = true;
if (i != 0)
{
diagnostics.Add(ErrorCode.ERR_RefValBoundMustBeFirst, syntax.GetFirstToken().GetLocation());
}
var constraintSyntax = (ClassOrStructConstraintSyntax)syntax;
SyntaxToken questionToken = constraintSyntax.QuestionToken;
if (questionToken.IsKind(SyntaxKind.QuestionToken))
{
constraints |= TypeParameterConstraintKind.NullableReferenceType;
LazyMissingNonNullTypesContextDiagnosticInfo.ReportNullableReferenceTypesIfNeeded(IsNullableEnabled(questionToken), questionToken.GetLocation(), diagnostics);
}
else if (IsNullableEnabled(constraintSyntax.ClassOrStructKeyword))
{
constraints |= TypeParameterConstraintKind.NotNullableReferenceType;
}
else
{
constraints |= TypeParameterConstraintKind.ReferenceType;
}
continue;
case SyntaxKind.StructConstraint:
hasTypeLikeConstraint = true;
if (i != 0)
{
diagnostics.Add(ErrorCode.ERR_RefValBoundMustBeFirst, syntax.GetFirstToken().GetLocation());
}
constraints |= TypeParameterConstraintKind.ValueType;
continue;
case SyntaxKind.ConstructorConstraint:
if ((constraints & TypeParameterConstraintKind.ValueType) != 0)
{
diagnostics.Add(ErrorCode.ERR_NewBoundWithVal, syntax.GetFirstToken().GetLocation());
}
if ((constraints & TypeParameterConstraintKind.Unmanaged) != 0)
{
diagnostics.Add(ErrorCode.ERR_NewBoundWithUnmanaged, syntax.GetFirstToken().GetLocation());
}
if (i != n - 1)
{
diagnostics.Add(ErrorCode.ERR_NewBoundMustBeLast, syntax.GetFirstToken().GetLocation());
}
constraints |= TypeParameterConstraintKind.Constructor;
continue;
case SyntaxKind.TypeConstraint:
{
hasTypeLikeConstraint = true;
var typeConstraintSyntax = (TypeConstraintSyntax)syntax;
var typeSyntax = typeConstraintSyntax.Type;
var typeSyntaxKind = typeSyntax.Kind();
// For pointer types, don't report this error. It is already reported during binding typeSyntax below.
switch (typeSyntaxKind)
{
case SyntaxKind.PredefinedType:
case SyntaxKind.PointerType:
case SyntaxKind.NullableType:
break;
default:
if (!SyntaxFacts.IsName(typeSyntax.Kind()))
{
diagnostics.Add(ErrorCode.ERR_BadConstraintType, typeSyntax.GetLocation());
}
break;
}
var type = BindTypeOrUnmanagedKeyword(typeSyntax, diagnostics, out var isUnmanaged);
if (isUnmanaged)
{
if (constraints != 0 || constraintTypes.Any())
{
diagnostics.Add(ErrorCode.ERR_UnmanagedConstraintMustBeFirst, typeSyntax.GetLocation());
continue;
}
// This should produce diagnostics if the types are missing
GetWellKnownType(WellKnownType.System_Runtime_InteropServices_UnmanagedType, diagnostics, typeSyntax);
GetSpecialType(SpecialType.System_ValueType, diagnostics, typeSyntax);
constraints |= TypeParameterConstraintKind.Unmanaged;
continue;
}
constraintTypes.Add(type);
syntaxBuilder.Add(typeConstraintSyntax);
}
continue;
default:
throw ExceptionUtilities.UnexpectedValue(syntax.Kind());
}
}
if (!hasTypeLikeConstraint && !IsNullableEnabled(typeParameterSyntax.Identifier))
{
constraints |= TypeParameterConstraintKind.ObliviousNullabilityIfReferenceType;
}
return(TypeParameterConstraintClause.Create(constraints, constraintTypes.ToImmutableAndFree(), syntaxBuilder.ToImmutableAndFree()));
}
private (TypeParameterConstraintClause, ArrayBuilder <TypeConstraintSyntax>?) BindTypeParameterConstraints(TypeParameterSyntax typeParameterSyntax, TypeParameterConstraintClauseSyntax constraintClauseSyntax, bool isForOverride, DiagnosticBag diagnostics)
{
var constraints = TypeParameterConstraintKind.None;
ArrayBuilder <TypeWithAnnotations>? constraintTypes = null;
ArrayBuilder <TypeConstraintSyntax>?syntaxBuilder = null;
SeparatedSyntaxList <TypeParameterConstraintSyntax> constraintsSyntax = constraintClauseSyntax.Constraints;
Debug.Assert(!InExecutableBinder); // Cannot eagerly report diagnostics handled by LazyMissingNonNullTypesContextDiagnosticInfo
bool hasTypeLikeConstraint = false;
bool reportedOverrideWithConstraints = false;
for (int i = 0, n = constraintsSyntax.Count; i < n; i++)
{
var syntax = constraintsSyntax[i];
switch (syntax.Kind())
{
case SyntaxKind.ClassConstraint:
hasTypeLikeConstraint = true;
if (i != 0)
{
diagnostics.Add(ErrorCode.ERR_RefValBoundMustBeFirst, syntax.GetFirstToken().GetLocation());
if (isForOverride && (constraints & (TypeParameterConstraintKind.ValueType | TypeParameterConstraintKind.ReferenceType)) != 0)
{
continue;
}
}
var constraintSyntax = (ClassOrStructConstraintSyntax)syntax;
SyntaxToken questionToken = constraintSyntax.QuestionToken;
if (questionToken.IsKind(SyntaxKind.QuestionToken))
{
constraints |= TypeParameterConstraintKind.NullableReferenceType;
if (isForOverride)
{
reportOverrideWithConstraints(ref reportedOverrideWithConstraints, syntax, diagnostics);
}
else
{
LazyMissingNonNullTypesContextDiagnosticInfo.ReportNullableReferenceTypesIfNeeded(AreNullableAnnotationsEnabled(questionToken), questionToken.GetLocation(), diagnostics);
}
}
else if (isForOverride || AreNullableAnnotationsEnabled(constraintSyntax.ClassOrStructKeyword))
{
constraints |= TypeParameterConstraintKind.NotNullableReferenceType;
}
else
{
constraints |= TypeParameterConstraintKind.ReferenceType;
}
continue;
case SyntaxKind.StructConstraint:
hasTypeLikeConstraint = true;
if (i != 0)
{
diagnostics.Add(ErrorCode.ERR_RefValBoundMustBeFirst, syntax.GetFirstToken().GetLocation());
if (isForOverride && (constraints & (TypeParameterConstraintKind.ValueType | TypeParameterConstraintKind.ReferenceType)) != 0)
{
continue;
}
}
constraints |= TypeParameterConstraintKind.ValueType;
continue;
case SyntaxKind.ConstructorConstraint:
if (isForOverride)
{
reportOverrideWithConstraints(ref reportedOverrideWithConstraints, syntax, diagnostics);
continue;
}
if ((constraints & TypeParameterConstraintKind.ValueType) != 0)
{
diagnostics.Add(ErrorCode.ERR_NewBoundWithVal, syntax.GetFirstToken().GetLocation());
}
if ((constraints & TypeParameterConstraintKind.Unmanaged) != 0)
{
diagnostics.Add(ErrorCode.ERR_NewBoundWithUnmanaged, syntax.GetFirstToken().GetLocation());
}
if (i != n - 1)
{
diagnostics.Add(ErrorCode.ERR_NewBoundMustBeLast, syntax.GetFirstToken().GetLocation());
}
constraints |= TypeParameterConstraintKind.Constructor;
continue;
case SyntaxKind.TypeConstraint:
if (isForOverride)
{
reportOverrideWithConstraints(ref reportedOverrideWithConstraints, syntax, diagnostics);
}
else
{
hasTypeLikeConstraint = true;
if (constraintTypes == null)
{
constraintTypes = ArrayBuilder <TypeWithAnnotations> .GetInstance();
syntaxBuilder = ArrayBuilder <TypeConstraintSyntax> .GetInstance();
}
var typeConstraintSyntax = (TypeConstraintSyntax)syntax;
var typeSyntax = typeConstraintSyntax.Type;
var type = BindTypeOrConstraintKeyword(typeSyntax, diagnostics, out ConstraintContextualKeyword keyword);
switch (keyword)
{
case ConstraintContextualKeyword.Unmanaged:
if (i != 0)
{
diagnostics.Add(ErrorCode.ERR_UnmanagedConstraintMustBeFirst, typeSyntax.GetLocation());
continue;
}
// This should produce diagnostics if the types are missing
GetWellKnownType(WellKnownType.System_Runtime_InteropServices_UnmanagedType, diagnostics, typeSyntax);
GetSpecialType(SpecialType.System_ValueType, diagnostics, typeSyntax);
constraints |= TypeParameterConstraintKind.Unmanaged;
continue;
case ConstraintContextualKeyword.NotNull:
if (i != 0)
{
diagnostics.Add(ErrorCode.ERR_NotNullConstraintMustBeFirst, typeSyntax.GetLocation());
}
constraints |= TypeParameterConstraintKind.NotNull;
continue;
case ConstraintContextualKeyword.None:
break;
default:
throw ExceptionUtilities.UnexpectedValue(keyword);
}
constraintTypes.Add(type);
syntaxBuilder !.Add(typeConstraintSyntax);
}
continue;
default:
throw ExceptionUtilities.UnexpectedValue(syntax.Kind());
}
}
if (!isForOverride && !hasTypeLikeConstraint && !AreNullableAnnotationsEnabled(typeParameterSyntax.Identifier))
{
constraints |= TypeParameterConstraintKind.ObliviousNullabilityIfReferenceType;
}
Debug.Assert(!isForOverride ||
(constraints & (TypeParameterConstraintKind.ReferenceType | TypeParameterConstraintKind.ValueType)) != (TypeParameterConstraintKind.ReferenceType | TypeParameterConstraintKind.ValueType));
return(TypeParameterConstraintClause.Create(constraints, constraintTypes?.ToImmutableAndFree() ?? ImmutableArray <TypeWithAnnotations> .Empty), syntaxBuilder);