{"ast_node_type":"other","tokens":[{"end":96,"kind":"keyword","start":0,"text":"impl<'tcx>"}]}
impl<'tcx> Rollback<sv::UndoLog<ut::Delegate<TyVidEqKey<'tcx>>>> for TypeVariableStorage<'tcx> {
    fn reverse(&mut self, undo: sv::UndoLog<ut::Delegate<TyVidEqKey<'tcx>>>) {