{"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"assert_matches!(diagnostic.level,"}]}
            assert_matches!(diagnostic.level, Error | ForceWarning | Warning | Allow | Expect);
            // stashed below, so they'll trigger the must_produce_diag check.
            self.future_breakage_diagnostics.push(diagnostic.clone());