{"ast_node_type":"variable","tokens":[{"end":31,"kind":"keyword","start":0,"text":"let"}]}
                let trait_ref =
            &Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, ty) => {
                    ty::TraitRef::new(tcx, tcx.require_lang_item(LangItem::Sized, span), [ty]);