{"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"impl<'a,"}]}
impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
    fn flat_map_item(&mut self, node: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {