[ffigen] [objc] Incorrect code generation for NSArray differenceFromArray

[brianquinlan]

The generated code is (ffigen 20.0):

  objc.NSOrderedCollectionDifference differenceFromArray$1(
    objc.NSArray other, {
    required objc.NSOrderedCollectionDifferenceCalculationOptions withOptions,
  }) {
    objc.checkOsVersionInternal(
      'NSArray.differenceFromArray:withOptions:',
      iOS: (false, (13, 0, 0)),
      macOS: (false, (10, 15, 0)),
    );
    final $ret = _objc_msgSend_1wtpmu7(
      object$.ref.pointer,
      _sel_differenceFromArray_withOptions_,
      other.ref.pointer,
      // The argument type 'NSOrderedCollectionDifferenceCalculationOptions' can't be assigned to the parameter type 'int'. 
      withOptions,
    );
    return objc.NSOrderedCollectionDifference.fromPointer(
      $ret,
      retain: true,
      release: true,
    );
  }

[liamappelbe]

I think you're using package:objective_c 8.1.0. In v9, this enum was converted to an int. I get correct code gen when I try to generate this category.

[brianquinlan]

I did switch to v9, here is the PR:
dart-lang/http#1850

[liamappelbe]

Oh, looks like a bug specifically to do with imported enums.