TypeError due to lack of inference

main.dart

typedef PathFunction = String Function([List<String> segment]);

PathFunction createPathFunction() {
  // The type of this default list is not inferred from context.
  // Typing the LHS or applying type arguments to the RHS fixes this.
  return ([args = const []]) {
    return '/${args.join('/')}';
  };
}

void main() {
  final toPath = createPathFunction();
  // Passing a list with the correct type works.
  print(toPath(['hello', 'world']));
  // Even passing a list with no element works, so inference from the
  // closure signature works.
  print(toPath([]));
  // Omitting the list argument causes a runtime error.
  print(toPath());
}