pkg/front_end/testcases/inference/bug32291.dart

// Copyright (c) 2018, 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.

library test;

void main() {
  var l = [
    ["hi", "world"],
    null,
  ];
  var i1 = l.map((ll) => ll ?? []);
  var i2 = i1.map((List<String> l) => l.length);
  print(i2);
}