The message
describes the erroneous argument.
Existing code may be using message
to hold the invalid value. If the message
is not a String, it is assumed to be a value instead of a message.
ArgumentError([this.message]) : invalidValue = null, _hasValue = false, name = null;
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/2.0.0/dart-core/ArgumentError/ArgumentError.html