public override void VisitNamespaceDeclaration(NamespaceDeclarationSyntax node)
{
var simpleNamespaces = node.Usings.Where(usingDirective => usingDirective.Alias == null);
var newUsingDirectives = new HashSet <EquivalentNameSyntax>();
newUsingDirectives.UnionWith(usingDirectivesFromParent);
newUsingDirectives.UnionWith(simpleNamespaces.Select(x => new EquivalentNameSyntax(x.Name)));
// We visit the namespace declaration with the updated set of parent 'usings', this is needed in case of nested namespaces
var visitingNamespace = context.SemanticModel.GetSymbolInfo(node.Name).Symbol as INamespaceSymbol;
var visitor = new CSharpRemovableUsingWalker(context, newUsingDirectives.ToImmutableHashSet(), visitingNamespace);
VisitContent(visitor, node.Members, node.DescendantTrivia());
CheckUnnecessaryUsings(context, simpleNamespaces, visitor.necessaryNamespaces);
necessaryNamespaces.UnionWith(visitor.necessaryNamespaces);
}
