// If this is Y in X.Y, walk up to X.Y
static TypeSyntax WalkUpCurrentQualifiedName(TypeSyntax node)
{
while (node.IsParentKind(SyntaxKind.QualifiedName, out QualifiedNameSyntax? qualifiedName) &&
qualifiedName.Right == node)
{
node = qualifiedName;
}
return(node);
}
internal override bool TryAnalyzeVariableDeclaration(
TypeSyntax typeName, SemanticModel semanticModel,
OptionSet optionSet, CancellationToken cancellationToken)
{
// var (x, y) = e;
// foreach (var (x, y) in e) ...
if (typeName.IsParentKind(SyntaxKind.DeclarationExpression))
{
var parent = (DeclarationExpressionSyntax)typeName.Parent;
if (parent.Designation.IsKind(SyntaxKind.ParenthesizedVariableDesignation))
{
return(true);
}
}
// If it is currently not var, explicit typing exists, return.
// this also takes care of cases where var is mapped to a named type via an alias or a class declaration.
if (!typeName.StripRefIfNeeded().IsTypeInferred(semanticModel))
{
return(false);
}
if (typeName.Parent.IsKind(SyntaxKind.VariableDeclaration) &&
typeName.Parent.Parent.IsKind(SyntaxKind.LocalDeclarationStatement, SyntaxKind.ForStatement, SyntaxKind.UsingStatement))
{
// check assignment for variable declarations.
var variableDeclaration = (VariableDeclarationSyntax)typeName.Parent;
var variable = variableDeclaration.Variables.First();
if (!AssignmentSupportsStylePreference(
variable.Identifier, typeName, variable.Initializer.Value,
semanticModel, optionSet, cancellationToken))
{
return(false);
}
// This error case is handled by a separate code fix (UseExplicitTypeForConst).
if ((variableDeclaration.Parent as LocalDeclarationStatementSyntax)?.IsConst == true)
{
return(false);
}
}
else if (typeName.Parent is ForEachStatementSyntax foreachStatement &&
foreachStatement.Type == typeName)
{
if (!AssignmentSupportsStylePreference(
foreachStatement.Identifier, typeName, foreachStatement.Expression,
semanticModel, optionSet, cancellationToken))
{
return(false);
}
}
return(true);
}
private static bool IsLanguageRestrictedToNonNullForm(TypeSyntax node)
{
// Simplify syntax checks by walking up qualified names to an equivalent parent node.
node = WalkUpCurrentQualifiedName(node);
if (node.IsParentKind(SyntaxKind.QualifiedName, out QualifiedNameSyntax? qualifiedName) &&
qualifiedName.Left == node)
{
// Cannot dot off a nullable reference type
return(true);
}
if (node.IsParentKind(SyntaxKind.UsingDirective))
{
// Using directives cannot directly reference a nullable reference type
return(true);
}
if (node.IsParentKind(SyntaxKind.SimpleBaseType))
{
// Cannot derive directly from a nullable reference type
return(true);
}
if (node.IsParentKind(SyntaxKind.NamespaceDeclaration, SyntaxKind.FileScopedNamespaceDeclaration))
{
// Namespace names cannot be nullable reference types
return(true);
}
if (node.IsParentKind(SyntaxKind.NameEquals) && node.Parent.IsParentKind(SyntaxKind.UsingDirective))
{
// This is the alias or the target type of a using alias directive, neither of which can be nullable
//
// using CustomException = System.Exception;
// ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^
return(true);
}
return(false);
protected override bool TryAnalyzeVariableDeclaration(TypeSyntax typeName, SemanticModel semanticModel, OptionSet optionSet, CancellationToken cancellationToken, out TextSpan issueSpan)
{
// If it is already var, return.
if (typeName.IsTypeInferred(semanticModel))
{
issueSpan = default(TextSpan);
return(false);
}
var candidateReplacementNode = SyntaxFactory.IdentifierName("var");
var candidateIssueSpan = typeName.Span;
// If there exists a type named var, return.
var conflict = semanticModel.GetSpeculativeSymbolInfo(typeName.SpanStart, candidateReplacementNode, SpeculativeBindingOption.BindAsTypeOrNamespace).Symbol;
if (conflict?.IsKind(SymbolKind.NamedType) == true)
{
issueSpan = default(TextSpan);
return(false);
}
if (typeName.Parent.IsKind(SyntaxKind.VariableDeclaration) &&
typeName.Parent.IsParentKind(SyntaxKind.LocalDeclarationStatement, SyntaxKind.ForStatement, SyntaxKind.UsingStatement))
{
var variableDeclaration = (VariableDeclarationSyntax)typeName.Parent;
// implicitly typed variables cannot be constants.
if ((variableDeclaration.Parent as LocalDeclarationStatementSyntax)?.IsConst == true)
{
issueSpan = default(TextSpan);
return(false);
}
var variable = variableDeclaration.Variables.Single();
if (AssignmentSupportsStylePreference(
variable.Identifier, typeName, variable.Initializer.Value,
semanticModel, optionSet, cancellationToken))
{
issueSpan = candidateIssueSpan;
return(true);
}
}
else if (typeName.IsParentKind(SyntaxKind.ForEachStatement))
{
issueSpan = candidateIssueSpan;
return(true);
}
issueSpan = default(TextSpan);
return(false);
}
protected override bool TryAnalyzeVariableDeclaration(TypeSyntax typeName, SemanticModel semanticModel, OptionSet optionSet, CancellationToken cancellationToken, out TextSpan issueSpan)
{
issueSpan = default;
// var (x, y) = e;
// foreach (var (x, y) in e) ...
if (typeName.IsParentKind(SyntaxKind.DeclarationExpression))
{
var parent = (DeclarationExpressionSyntax)typeName.Parent;
if (parent.Designation.IsKind(SyntaxKind.ParenthesizedVariableDesignation))
{
issueSpan = typeName.Span;
return(true);
}
}
// If it is currently not var, explicit typing exists, return.
// this also takes care of cases where var is mapped to a named type via an alias or a class declaration.
if (!typeName.IsTypeInferred(semanticModel))
{
return(false);
}
if (typeName.Parent.IsKind(SyntaxKind.VariableDeclaration) &&
typeName.Parent.Parent.IsKind(SyntaxKind.LocalDeclarationStatement, SyntaxKind.ForStatement, SyntaxKind.UsingStatement))
{
// check assignment for variable declarations.
var variable = ((VariableDeclarationSyntax)typeName.Parent).Variables.First();
if (!AssignmentSupportsStylePreference(
variable.Identifier, typeName, variable.Initializer.Value,
semanticModel, optionSet, cancellationToken))
{
return(false);
}
}
else if (typeName.Parent.IsKind(SyntaxKind.ForEachStatement))
{
var foreachStatement = (ForEachStatementSyntax)typeName.Parent;
if (!AssignmentSupportsStylePreference(
foreachStatement.Identifier, typeName, foreachStatement.Expression,
semanticModel, optionSet, cancellationToken))
{
return(false);
}
}
issueSpan = typeName.Span;
return(true);
}
public static Accessibility DetermineAccessibilityConstraint(
this SemanticModel semanticModel,
TypeSyntax type,
CancellationToken cancellationToken)
{
if (type == null)
{
return(Accessibility.Private);
}
type = GetOutermostType(type);
// Interesting cases based on 3.5.4 Accessibility constraints in the language spec.
// If any of the below hold, then we will override the default accessibility if the
// constraint wants the type to be more accessible. i.e. if by default we generate
// 'internal', but a constraint makes us 'public', then be public.
// 1) The direct base class of a class type must be at least as accessible as the
// class type itself.
//
// 2) The explicit base interfaces of an interface type must be at least as accessible
// as the interface type itself.
if (type != null)
{
if (type.Parent is BaseTypeSyntax && type.Parent.IsParentKind(SyntaxKind.BaseList) && ((BaseTypeSyntax)type.Parent).Type == type)
{
var containingType = semanticModel.GetDeclaredSymbol(type.GetAncestor <BaseTypeDeclarationSyntax>(), cancellationToken) as INamedTypeSymbol;
if (containingType != null && containingType.TypeKind == TypeKind.Interface)
{
return(containingType.DeclaredAccessibility);
}
else if (((BaseListSyntax)type.Parent.Parent).Types[0] == type.Parent)
{
return(containingType.DeclaredAccessibility);
}
}
}
// 4) The type of a constant must be at least as accessible as the constant itself.
// 5) The type of a field must be at least as accessible as the field itself.
if (type.IsParentKind(SyntaxKind.VariableDeclaration) &&
type.Parent.IsParentKind(SyntaxKind.FieldDeclaration))
{
var variableDeclaration = (VariableDeclarationSyntax)type.Parent;
return(semanticModel.GetDeclaredSymbol(
variableDeclaration.Variables[0], cancellationToken).DeclaredAccessibility);
}
// Also do the same check if we are in an object creation expression
if (type.IsParentKind(SyntaxKind.ObjectCreationExpression) &&
type.Parent.IsParentKind(SyntaxKind.EqualsValueClause) &&
type.Parent.Parent.IsParentKind(SyntaxKind.VariableDeclarator) &&
type.Parent.Parent.Parent.IsParentKind(SyntaxKind.VariableDeclaration) &&
type.Parent.Parent.Parent.Parent.IsParentKind(SyntaxKind.FieldDeclaration))
{
var variableDeclaration = (VariableDeclarationSyntax)type.Parent.Parent.Parent.Parent;
return(semanticModel.GetDeclaredSymbol(
variableDeclaration.Variables[0], cancellationToken).DeclaredAccessibility);
}
// 3) The return type of a delegate type must be at least as accessible as the
// delegate type itself.
// 6) The return type of a method must be at least as accessible as the method
// itself.
// 7) The type of a property must be at least as accessible as the property itself.
// 8) The type of an event must be at least as accessible as the event itself.
// 9) The type of an indexer must be at least as accessible as the indexer itself.
// 10) The return type of an operator must be at least as accessible as the operator
// itself.
if (type.IsParentKind(SyntaxKind.DelegateDeclaration) ||
type.IsParentKind(SyntaxKind.MethodDeclaration) ||
type.IsParentKind(SyntaxKind.PropertyDeclaration) ||
type.IsParentKind(SyntaxKind.EventDeclaration) ||
type.IsParentKind(SyntaxKind.IndexerDeclaration) ||
type.IsParentKind(SyntaxKind.OperatorDeclaration))
{
return(semanticModel.GetDeclaredSymbol(
type.Parent, cancellationToken).DeclaredAccessibility);
}
// 3) The parameter types of a delegate type must be at least as accessible as the
// delegate type itself.
// 6) The parameter types of a method must be at least as accessible as the method
// itself.
// 9) The parameter types of an indexer must be at least as accessible as the
// indexer itself.
// 10) The parameter types of an operator must be at least as accessible as the
// operator itself.
// 11) The parameter types of an instance constructor must be at least as accessible
// as the instance constructor itself.
if (type.IsParentKind(SyntaxKind.Parameter) && type.Parent.IsParentKind(SyntaxKind.ParameterList))
{
if (type.Parent.Parent.IsParentKind(SyntaxKind.DelegateDeclaration) ||
type.Parent.Parent.IsParentKind(SyntaxKind.MethodDeclaration) ||
type.Parent.Parent.IsParentKind(SyntaxKind.IndexerDeclaration) ||
type.Parent.Parent.IsParentKind(SyntaxKind.OperatorDeclaration))
{
return(semanticModel.GetDeclaredSymbol(
type.Parent.Parent.Parent, cancellationToken).DeclaredAccessibility);
}
if (type.Parent.Parent.IsParentKind(SyntaxKind.ConstructorDeclaration))
{
var symbol = semanticModel.GetDeclaredSymbol(type.Parent.Parent.Parent, cancellationToken);
if (!symbol.IsStatic)
{
return(symbol.DeclaredAccessibility);
}
}
}
// 8) The type of an event must be at least as accessible as the event itself.
if (type.IsParentKind(SyntaxKind.VariableDeclaration) &&
type.Parent.IsParentKind(SyntaxKind.EventFieldDeclaration))
{
var variableDeclaration = (VariableDeclarationSyntax)type.Parent;
var symbol = semanticModel.GetDeclaredSymbol(variableDeclaration.Variables[0], cancellationToken);
if (symbol != null)
{
return(symbol.DeclaredAccessibility);
}
}
return(Accessibility.Private);
}