{"ast_node_type":"variable","tokens":[{"end":98,"kind":"keyword","start":0,"text":"let"}]}
            let const_def_id = self.tcx.require_lang_item(LangItem::ConstPanicFmt, self.tcx.span);
            // For panic_fmt, call const_panic_fmt instead.
            let new_instance = ty::Instance::expect_resolve(