pkg/front_end/testcases/inference/inferred_type_custom_index_op_via_interface.dart

// Copyright (c) 2017, 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.
// @dart=2.9
/*@testedFeatures=inference*/
library test;

class I {
  bool operator [](int index) => true;
}

abstract class C implements I {}

f() {
  C c;
  var /*@ type=bool* */ x = c /*@target=I.[]*/ [0];
}

main() {}