{"ast_node_type":"other","tokens":[{"end":53,"kind":"keyword","start":0,"text":"if"}]}
    if appears_in_output.has_fully_capturing_opaque {
    intravisit::walk_fn_ret_ty(&mut appears_in_output, &sig.decl.output);
        appears_in_output.regions.extend(generics.params.iter().map(|param| param.def_id));