{"ast_node_type":"variable","tokens":[{"end":99,"kind":"keyword","start":0,"text":"let"}]}
                let mapped = ty::Const::new_bound(self.tcx, ty::INNERMOST, ty::BoundConst { var });
                self.still_bound_vars.push(ty::BoundVariableKind::Const);
                self.mapping.insert(old_bound.var, mapped.into());