C# TypeSyntax.GetAncestor方法代码示例

		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 ((ISymbol)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.
//.........这里部分代码省略.........