Microsoft.CodeAnalysis.LanguageService.AbstractDeclaredSymbolInfoFactoryService<TCompilationUnitSyntax, TUsingDirectiveSyntax, TNamespaceDeclarationSyntax, TTypeDeclarationSyntax, TEnumDeclarationSyntax, TMethodDeclarationSyntax, TMemberDeclarationSyntax, TNameSyntax, TQualifiedNameSyntax, TIdentifierNameSyntax>.GetRootNamespace(Microsoft.CodeAnalysis.CompilationOptions)