{"ast_node_type":"function","tokens":[{"end":64,"kind":"keyword","start":0,"text":"fn"}]}
    fn visit_local(&mut self, local: &'tcx hir::LetStmt<'tcx>) {
impl<'a, 'tcx> Visitor<'tcx> for Liveness<'a, 'tcx> {
        self.check_unused_vars_in_pat(local.pat, None, None, |spans, hir_id, ln, var| {