// Copyright (c) 2019, 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.

/// @assertion A simple member invocation on a target expression X is an
/// expression of one of the forms:
///           Member invocation on target X	     Corresponding member name
/// X[expr1]++, X[expr1]--, ++X[expr1], --X[expr1]	            []
/// @description Check explicit extension member invocation in form of --X[expr1]
/// @issue 39198
/// @issue 39254
/// @author sgrekhov@unipro.ru


class C {
  int value;
  C() : value = 0 {}
  init() {
    value = 0;
  }
  C operator [](int index) {
    this.value += index;
    return this;
  }
  void operator []=(int index, C other) {
    this.value += other.value + index;
  }
  C operator -(int val) {
    this.value += val;
    return this;
  }
}

extension Ext1 on C {
  C operator [](int index) {
    this.value += index + 1;
    return this;
  }
}

extension Ext2 on C {
  void operator []=(int index, C other) {
    this.value += other.value + index + 2;
  }
}

main() {
  C c = C();
  --Ext1(c)[42];
//         ^^^^
// [analyzer] unspecified
// [cfe] unspecified

  --Ext2(c)[42];
//         ^^^^
// [analyzer] unspecified
// [cfe] unspecified
}