{"ast_node_type":"other","tokens":[{"end":99,"kind":"keyword","start":0,"text":"//"}]}
        // We could have invoked reverse lookup for a `MovePathIndex` every time, but unfortunately
            Rc::clone(self.visited.entry(block).or_insert_with(make_new_path_set));
        // it is expensive. Let's cache them in `self.block_drop_value_info`.