{"ast_node_type":"variable","tokens":[{"end":60,"kind":"keyword","start":0,"text":"let"}]}
    let const_body = ecx.expr_block(ecx.block(span, stmts));
    let const_ty = ecx.ty(ty_span, TyKind::Tup(ThinVec::new()));
    let const_item = ecx.item_const(span, Ident::new(kw::Underscore, span), const_ty, const_body);