{"ast_node_type":"variable","tokens":[{"end":90,"kind":"keyword","start":0,"text":"let"}]}
                let parent_def_id = self.tcx.hir_get_parent_item(call_expr.hir_id).def_id;
                let mut call_finder = FindClosureArg { tcx: self.tcx, calls: vec![] };
                match self.tcx.hir_node_by_def_id(parent_def_id) {