// Copyright (c) 2020, 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 We say that a variable x is promotable via type test with type T
/// given variable model VM if
///
/// VM = VariableModel(declared, promoted, tested, assigned, unassigned, captured)
///  and captured is false
///  and S is the current type of x in VM
///  and not S <: T
///  and T <: S or (S is X extends R and T <: R) or (S is X & R and T <: R)
///
/// @description Checks that a variable is not promotable if T is not subtype of
/// S
///
/// @author sgrekhov@unipro.ru


class X {}
class R extends X {}
class T {
  int foo() => 42;
}

main() {
  X x = new R();
  if (x is R) {
    if (x is T) {
      x.foo();
//      ^^^
// [analyzer] unspecified
// [cfe] unspecified
    }
  }
}