pkg/front_end/testcases/general/issue48323.dart

// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

void Function<T>()? genericFunction;

void foo(void Function()? arg) {
  print(arg);
}

void main() {
  foo(genericFunction);
}