syntax_data: {"ast_node_type":"variable","tokens":[{"end":76,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let def_id = tcx.require_lang_item(LangItem::MaybeUninit, DUMMY_SP);
context_before:     pub fn new_maybe_uninit(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
context_after:         Ty::new_generic_adt(tcx, def_id, ty)