{"ast_node_type":"variable","tokens":[{"end":73,"kind":"keyword","start":0,"text":"let"}]}
    let Ok(ty) = tcx.try_normalize_erasing_regions(typing_env, ty) else {
        .unwrap_or_else(|| tcx.require_lang_item(LangItem::Copy, span));
        tcx.dcx().span_delayed_bug(span, "could not normalize field type");