Constructors can't be used in higher order functions

[gaaclarke]

Description

I have to wrap constructors in factory methods in order to use them in higher-ordrer functions. I expect that in a context where a function is required that has the same signature as the constructor, a type name should be interpreted as the constructor.

Code

/// A [map] function that takes in 2 iterables.
Iterable<V> _map2<T, U, V>(
    Iterable<T> ts, Iterable<U> us, V Function(T t, U u) func) sync* {
  final Iterator<T> itt = ts.iterator;
  final Iterator<U> itu = us.iterator;
  bool uMoveNext = itu.moveNext();
  bool tMoveNext = itt.moveNext();
  while (uMoveNext && tMoveNext) {
    yield func(itt.current, itu.current);
    uMoveNext = itu.moveNext();
    tMoveNext = itt.moveNext();
  }
  if (itu.moveNext() || itt.moveNext()) {
    throw Exception('Arguments to _map2 aren\'t the same length.');
  }
}

class _Tuple<T, U> {
  _Tuple(this.first, this.second);
  static _Tuple<T, U> make<T, U>(T t, U u) => _Tuple<T, U>(t, u);
  T first;
  U second;
}

// WORKAROUND
Iterable<_Tuple<T, U>> _zip<T, U>(Iterable<T> ts, Iterable<U> us) =>
    _map2(ts, us, _Tuple.make);

// DOESN'T WORK
Iterable<_Tuple<T, U>> _zip<T, U>(Iterable<T> ts, Iterable<U> us) =>
    _map2(ts, us, _Tuple);

[lrhn]

We're working on it. #46228

[gaaclarke]

closing as a duplicate