{"ast_node_type":"other","tokens":[{"end":34,"kind":"keyword","start":0,"text":"diag.arg(\"pre\","}]}
        diag.arg("pre", self.pre);
        diag.span_help(self.src_sp, fluent::_subdiag::help);
        diag.arg("def_path", self.tcx.def_path_str(self.def_id));