{"ast_node_type":"variable","tokens":[{"end":86,"kind":"keyword","start":0,"text":"let"}]}
                let popped = self.hir_typeck_potentially_region_dependent_goals.pop();
            UndoLog::PushHirTypeckPotentiallyRegionDependentGoal => {
                assert_matches!(popped, Some(_), "pushed goal but could not pop it");