{"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"let"}]}
    let unique_ty = tcx.type_of(unique_did).instantiate(tcx, args);
    let args = tcx.mk_args(&[pointee.into()]);
    let nonnull_ty = tcx.type_of(nonnull_did).instantiate(tcx, args);