private static boolean isMutatorMethod(PsiMethodCallExpression call, boolean exactType) {
    MutationSignature sig = MutationSignature.fromCall(call);
    if (sig.equals(MutationSignature.pure().alsoMutatesThis())) return true;
    if (exactType) {
      PsiMethod method = call.resolveMethod();
      if (PropertyUtil.isSimpleSetter(method)) return true;
    }
    return false;
  }
private static boolean isMutatorMethod(PsiMethodCallExpression call, boolean exactType)