LanguageFeatures/Patterns/exhaustiveness_A01_t17.dart

// Copyright (c) 2023, 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 But switch statements must only be exhaustive when the matched
/// value is an always-exhaustive type, defined as:
/// - bool
/// - Null
/// - A enum type
/// - A type whose declaration is marked sealed
/// - T? where T is always-exhaustive
/// - FutureOr<T> for some type T that is always-exhaustive
/// - A record type whose fields all have always-exhaustive types
/// - A type variable X with bound T where T is always-exhaustive
/// - A promoted type variable X & T where T is always-exhaustive
///
/// All other types are not always-exhaustive. Then:
/// - It is a compile-time error if the cases in a switch statement or switch
///   collection element are not exhaustive and the static type of the matched
///   value is an always-exhaustive type. There is no error if a switch
///   statement is not exhaustive when the type is not an always-exhaustive type
///
/// @description Check that it is a compile-time error if a switch statement is
/// not exhaustive. Test a promoted type variable `X & T` where `T` is
/// always-exhaustive
/// @author sgrekhov22@gmail.com

class C {}
sealed class Sealed extends C {}
class C1 extends Sealed {}
class C2 extends Sealed {}

test1<T extends C>(T t) {
  if (t is Sealed) {
    switch (t) {
//  ^^^^^^
// [analyzer] unspecified
// [cfe] unspecified
      case C1():
    }
  }
}

test2<T>(T t) {
  if (t is bool?) {
    switch (t) {
//  ^^^^^^
// [analyzer] unspecified
// [cfe] unspecified
      case bool():
    }
  }
}

main() {
  test1<C1>(C1());
  test2<bool?>(true);
}