NoSuchMethodError: The method '_mulFromInteger' was called on null.

[RdeWilde]

I get this error NoSuchMethodError: The method '_mulFromInteger' was called on null. on several include files, but I can't understand why.
I tried adding it to the header-filter excludes too, but that didn't fix it either.

What is the problem?

Source file:

#include <netaddress.h>

Config:

ffigen:
  output: 'generated_bridge.dart'
  headers:
    - 'src/example/src/example.h'
  header-filter:
    exclude:
      - 'netaddress.h'
  name: 'Bridge'
  description: 'Bridge'
  array-workaround: true

Last part of output:

Unhandled exception:
NoSuchMethodError: The method '_mulFromInteger' was called on null.
Receiver: null
Tried calling: _mulFromInteger(1)
#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
dart-lang/ffigen#1      int.* (dart:core-patch/integers.dart:16:38)
dart-lang/ffigen#2      ArrayHelper.expandedArrayLength (package:ffigen/src/code_generator/struc.dart:176:33)
dart-lang/ffigen#3      ArrayHelper.declarationString (package:ffigen/src/code_generator/struc.dart:196:25)
dart-lang/ffigen#4      Struc.toBindingString (package:ffigen/src/code_generator/struc.dart:111:29)
dart-lang/ffigen#5      Writer.generate (package:ffigen/src/code_generator/writer.dart:153:17)
dart-lang/ffigen#6      Library.generate (package:ffigen/src/code_generator/library.dart:106:14)
dart-lang/ffigen#7      Library.generateFile (package:ffigen/src/code_generator/library.dart:88:28)
dart-lang/ffigen#8      main (file:///home/robert/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/ffigen-0.1.2/bin/ffigen.dart:51:11)
dart-lang/ffigen#9      _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:299:32)
dart-lang/ffigen#10     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)
pub finished with exit code 255

[mannprerak2]

I was able to reproduce this issue for this header -

struct T1{
    int k;
    int a[];
};

This is happening due to flexible array member (a).

And the reason you are not able to exclude is because structs are auto added if any function depends on it. See #520