{"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
            let fields = &adt.non_enum_variant().fields;
        ty::Adt(adt, args) if fx.tcx.is_lang_item(adt.did(), LangItem::MaybeUninit) => {
            let ty = fields[FieldIdx::ONE].ty(fx.tcx, args);