// 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.

// @dart = 2.9

/// @assertion A type T0 is a subtype of a type T1 (written T0 <: T1) when:
/// Named Function Types: T0 is U0 Function<X0 extends B00, ..., Xk extends B0k>
///   (T0 x0, ..., Tn xn, {Tn+1 xn+1, ..., Tm xm})
///
/// and T1 is U1 Function<Y0 extends B10, ..., Yk extends B1k>(S0 y0, ..., Sn yn,
/// {Sn+1 yn+1, ..., Sq yq})
/// and {yn+1, ... , yq} subsetof {xn+1, ... , xm}
/// and Si[Z0/Y0, ..., Zk/Yk] <: Vi[Z0/X0, ..., Zk/Xk] for i in 0...n
/// and Si[Z0/Y0, ..., Zk/Yk] <: Tj[Z0/X0, ..., Zk/Xk] for i in n+1...q, yj = xi
/// and U0[Z0/X0, ..., Zk/Xk] <: U1[Z0/Y0, ..., Zk/Yk]
/// and B0i[Z0/X0, ..., Zk/Xk] === B1i[Z0/Y0, ..., Zk/Yk] for i in 0...k
/// where the Zi are fresh type variables with bounds B0i[Z0/X0, ..., Zk/Xk]
/// @description Check that if there is i in 0...n such that
/// Si[Z0/Y0, ..., Zk/Yk] is not subtype of Vi[Z0/X0, ..., Zk/Xk], then T0 is not
/// a subtype of T1
/// @author sgrekhov@unipro.ru
///
/// @description Check that if type T0 not a subtype of a type T1, then instance
/// of T0 cannot be be used as a return value of type T1. Return value is tested.
/// @author sgrekhov@unipro.ru
/// @author ngl@unipro.ru
///
/// This test is generated from named_function_types_fail_A21.dart and 
/// return_value_fail_x01.dart.
/// Don't modify it. If you want to change this test, change one of the files 
/// above and then run generator.dart to regenerate the tests.


// @dart = 2.9


class U0 extends U1 {}
class U1 {}
class V0 {}
class V1 {}
class V2 {}
class V3 {}
class V4 {}
class S0 extends V0 {}
class S1 {}
class S2 extends V2 {}
class S3 extends V3 {}

typedef T0 = U0 Function(V0 x0, V1 x1, {V2 x2, V3 x3, V4 x4});
typedef T1 = U1 Function(S0 y0, S1 y1, {S2 x2, S3 x3}); // S1 is not subtype of V1

U0 t0Func(V0 x0, V1 x1, {V2 x2, V3 x3, V4 x4}) => null;
U1 t1Func(S0 y0, S1 y1, {S2 x2, S3 x3}) => null;

T0 t0Instance = t0Func;
T1 t1Instance = t1Func;

// @dart = 2.9


T1 returnValueFunc() => t0Instance;
//                       ^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

class ReturnValueTest {
  static T1 staticTestMethod() => t0Instance;
//                                 ^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified
  T1 testMethod() => t0Instance;
//                    ^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

  T1 get testGetter => t0Instance;
//                      ^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified
}

main() {
  returnValueFunc();

  T1 returnValueLocalFunc() => t0Instance;
//                              ^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified
  returnValueLocalFunc();

  ReturnValueTest.staticTestMethod();
  new ReturnValueTest().testMethod();
  new ReturnValueTest().testGetter;
}