/// <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);