Source
bool get isErrorOrException {
bool _doCheck(InterfaceType type) {
return (type.element.library.isDartCore &&
(type.name == 'Exception' || type.name == 'Error'));
}
// if this class is itself Error or Exception, return true
if (_doCheck(_cls.type)) return true;
return _cls.allSupertypes.any(_doCheck);
}