{"ast_node_type":"variable","tokens":[{"end":35,"kind":"keyword","start":0,"text":"let"}]}
                    let named_key =
                        self.regioncx.name_regions_for_member_constraint(self.infcx.tcx, hidden_ty);
                        self.regioncx.name_regions_for_member_constraint(self.infcx.tcx, key);