LibTest/js_interop/staticInterop_A04_t02.dart

// Copyright (c) 2025, 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 `staticInterop` enables the JS annotated class to be treated as
/// a "static" interop class.
///
/// These classes implicitly all erase to the internal interceptor
/// `JavaScriptObject`, so they can be freely casted to and from other
/// [staticInterop] types, `dart:html` types, and `JSObject` from
/// `dart:js_interop`. Non-[staticInterop] `package:js` types can be casted to
/// [staticInterop] types, but the reverse can fail if the underlying value is a
/// `@Native`-reserved type (like `dart:html` types).
///
/// [staticInterop] classes have the following restrictions:
///  - They must contain a [JS] annotation, either from this library or from
///    `dart:js_interop`.
///  - They should not contain any instance members, inherited or otherwise, and
///    should instead use static extension members, which can be external or
///    non-external.
///  - They can only contain factories and `static` members. They can be
///    combined with [anonymous] to make external factories create new
///    JavaScript object literals instead.
///  - They should not implement, extend, or mixin non-[staticInterop] classes
///    and vice-versa.
///  - The annotation should only be applied to non-mixin classes and no other
///    declarations.
///
/// @description Checks that it is a compile-time error if a class annotated
/// with `@staticInterop` annotation extends, mixin or implements one without
/// this annotation.
/// @author sgrekhov22@gmail.com

import 'dart:js_interop';

class A {}

mixin class M {}

abstract interface class I {}

@staticInterop
@JS()
class C1 extends A {}
//    ^^
// [analyzer] unspecified
// [web] unspecified

@staticInterop
@JS()
class C2 with M {}
//    ^^
// [analyzer] unspecified
// [web] unspecified

@staticInterop
@JS()
class C3 implements I {}
//    ^^
// [analyzer] unspecified
// [web] unspecified

main() {
  print(C1);
  print(C2);
  print(C3);
}