{"ast_node_type":"variable","tokens":[{"end":91,"kind":"keyword","start":0,"text":"let"}]}
                    let actual = ty::fold_regions(tcx, actual, |re, _dbi| match re.kind() {
                        .instantiate(self.tcx, opaque_type_key.args);
                        ty::ReErased => self.next_region_var(RegionVariableOrigin::Misc(span)),