Missgenerated objc-bindings for nullable types

[brianquinlan]

Generated code:

typedef void  (^ListenerBlock1)(NSCachedURLResponse*  _Nullable);
ListenerBlock1 wrapListenerBlock_ObjCBlock_ffiVoid_NSCachedURLResponse(ListenerBlock1 block) {
  ListenerBlock1 wrapper = [^void(NSCachedURLResponse* arg0 _Nullable) {     /* <-- _Nullable */
    block([arg0 retain]);
  } copy];
  [block release];
  return wrapper;
}

The error is:

Parse Issue (Xcode): Expected ')'
/Users/bquinlan/dart/http/pkgs/cupertino_http/src/native_cupertino_bindings.m:3:60

Remove the _Nullable fixes the error.