// 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.

/// @assertion Instantiate to bound then computes an actual type argument list
/// for [G] as follows:
///
///   Let [Ui],[1] be [Si], for all [i] in [1 .. k]. (This is the "current
///   value" of the bound for type variable [i], at step [1]; in general we will
///   consider the current step, [m], and use data for that step, e.g., the
///   bound [Ui],[m], to compute the data for step [m + 1]).
///
///   Let [-->m] be a relation among the type variables [X1 .. Xk] such that
///   [Xp -->m Xq] iff [Xq] occurs in [Up],[m] (so each type variable is related
///   to, that is, depends on, every type variable in its bound, possibly
///   including itself). Let [==>m] be the transitive closure of [-->m]. For
///   each [m], let [Ui],[m+1], for [i] in [1 .. k], be determined by the
///   following iterative process:
///
///   1. If there exists a [j] in [1 .. k] such that [Xj ==>m X0j] (that is, if
///   the dependency graph has a cycle) let [M1 .. Mp] be the strongly connected
///   components (SCCs) with respect to [-->m] (that is, the maximal subsets of
///   [X1 .. Xk] where every pair of variables in each subset are related in
///   both directions by [==>m]; note that the SCCs are pairwise disjoint; also,
///   they are uniquely defined up to reordering, and the order does not
///   matter). Let [M] be the union of [M1 .. Mp] (that is, all variables that
///   participate in a dependency cycle). Let [i] be in [1 .. k]. If [Xi] does
///   not belong to [M] then [Ui,m+1 = Ui,m]. Otherwise there exists a [q] such
///   that [Xi] belongs to [Mq]; [Ui,m+1] is then obtained from [Ui,m] by
///   replacing every covariant occurrence of a variable in [Mq] by [dynamic],
///   and replacing every contravariant occurrence of a variable in [Mq] by
///   [Null].
///
///   2. Otherwise, (if no dependency cycle exists) let [j] be the lowest number
///   such that [Xj] occurs in [Up,m] for some [p] and [Xj -/->m Xq] for all [q]
///   in [1..k] (that is, [Uj,m] is closed, that is, the current bound of [Xj]
///   does not contain any type variables; but [Xj] is being depended on by the
///   bound of some other type variable). Then, for all [i] in [1 .. k],
///   [Ui,m+1] is obtained from [Ui,m] by replacing every covariant occurrence
///   of [Xj] by [Uj,m], and replacing every contravariant occurrence of [Xj] by
///   [Null].
///
///   3. Otherwise, (when no dependencies exist) terminate with the result
///   [<U1,m ..., Uk,m>].
///
/// @description Checks that instantiate-to-bounds works correctly for typedef
/// with two related parameters:
/// typedef G<X extends Y, Y extends A<Y>> = void Function(Y)]
///
/// @Issue 41963, 41964
///
/// @author iarkh@unipro.ru

import "../../../../Utils/expect.dart";

class A<X> {}
typedef G<X extends Y, Y extends A<Y>> = void Function(Y);

test(G source) {
  var fsource = toF(source);

  F<G<A<dynamic>, Never>> target1 = fsource;
//                                  ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Never>, Never>> target2 = fsource;
//                                ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Null>, Never>> target3 = fsource;
//                               ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<dynamic, Never>> target4 = fsource;
//                               ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<Never, Never>> target5 = fsource;
//                             ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<Null, Never>> target6 = fsource;
//                            ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<dynamic>, dynamic>> target7 = fsource;
//                                    ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Never>, dynamic>> target8 = fsource;
//                                  ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Null>, dynamic>> target9 = fsource;
//                                 ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<dynamic, dynamic>> target10 = fsource;
//                                  ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<Never, dynamic>> target11 = fsource;
//                                ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<Null, dynamic>> target12 = fsource;
//                               ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<dynamic>, Null>> target13 = fsource;
//                                  ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Never>, Null>> target14 = fsource;
//                                ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Null>, Null>> target15 = fsource;
//                               ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<dynamic, Null>> target16 = fsource;
//                               ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<Never, Null>> target17 = fsource;
//                             ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<Null, Null>> target18 = fsource;
//                            ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Never>, A<dynamic>>> target19 = fsource;
//                                      ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<dynamic>, A<dynamic>>> target20 = fsource;
//                                       ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<dynamic>, A<Never>>> target21 = fsource;
//                                      ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Never>, A<Never>>> target22 = fsource;

  F<G<A<dynamic>, A<Null>>> target23 = fsource;
//                                     ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Null>, A<dynamic>>> target24 = fsource;
//                                     ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  F<G<A<Null>,  A<Null>>> target25 = fsource;
//                                   ^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified
}

main() {
  G? source;
  G == int;
}