{"ast_node_type":"function","tokens":[{"end":43,"kind":"keyword","start":0,"text":"fn"}]}
    fn visit_item(&mut self, i: &'a Item) {
impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
        // Pick the def data. This need not be unique, but the more