String toString()

Returns a string representation of this object.

Source 

String toString() {
  String nameString = "";
  if (name != null) {
    nameString = " ($name)";
  }
  var message = (this.message == null) ? "" : ": ${this.message}";
  String prefix = "$_errorName$nameString$message";
  if (!_hasValue) return prefix;
  // If we know the invalid value, we can try to describe the problem.
  String explanation = _errorExplanation;
  String errorValue = Error.safeToString(invalidValue);
  return "$prefix$explanation: $errorValue";
}