sS codeSafetyCheckResult(S code) {
  S safety = joinWithComma(getCodeFragmentSafety(code));
  if (neq(safety, "safe")) {
    Set<S> unknown = codeAnalysis_getUnknownIdentifiers(code);
    if (nempty(unknown)) safety += ". Unknown identifiers: " + joinWithComma(unknown);
  }
  ret safety;
}