{"ast_node_type":"other","tokens":[{"end":93,"kind":"keyword","start":0,"text":"//"}]}
        //   if the ADTs definition implies that it is {meta,}sized by for all possible args.
        //   As a performance optimization, `{meta,pointee,}sized_constraint(Adt)` can return `None`
        //   In this case, the builtin impl will have no nested subgoals. This is a