LanguageFeatures/Primary-constructors/static_processing_A21_t14.dart

// Copyright (c) 2026, 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 The semantics of the primary constructor is found in the
/// following steps, where `D` is the class, mixin class, extension type, or
/// enum declaration in the program that includes a primary constructor `k`, and
/// `D2` is the result of the derivation of the semantics of `D`. The derivation
/// step will delete elements that amount to the primary constructor.
/// Semantically, it will add a new constructor `k2`, and it will add zero or
/// more instance variable declarations.
/// ...
/// The formal parameter list `L2` of `k2` is identical to `L`, except that each
/// formal parameter is processed as follows.
/// ...
/// - Otherwise, it is a declaring parameter. A formal parameter (named or
///   positional) of the form `var T p` or `final T p` where `T` is a type and
///   `p` is an identifier is replaced in `L2` by `this.p`, along with its
///   default value, if any. The same is done in the case where the formal
///   parameter has the form `var p` or `final p`, and `T` is the declared type
///   of `p` which was obtained by inference. If the parameter has the modifier
///   `var` and `D` is an extension type declaration then a compile-time error
///   occurs. Otherwise, if `D` is not an extension type declaration, a semantic
///   instance variable declaration corresponding to the syntax `T p;` or
///   `final T p;` is added to `D2`. It includes the modifier `final` if and
///   only if the parameter in `L` has the modifier `final` and `D` is not an
///   extension type declaration. Otherwise, if `D` is an extension type
///   declaration then the name of `p` specifies the name of the representation
///   variable. In all cases, if `p` has the modifier `covariant` then this
///   modifier is removed from the parameter in `L2`, and it is added to the
///   instance variable declaration named `p`.
///
/// @description Check that it is a compile time error if the primary
/// constructor of an enum declares a `covariant var` variable.
/// @author sgrekhov22@gmail.com

// SharedOptions=--enable-experiment=primary-constructors

enum E1(covariant var int x) {
//                ^^^
// [analyzer] unspecified
// [cfe] unspecified
  e0(0);
}

enum E2.named([covariant var int x = 0]) {
//                       ^^^
// [analyzer] unspecified
// [cfe] unspecified
  e0.named(0);
}

enum E3({covariant var int x = 0}) {
//                 ^^^
// [analyzer] unspecified
// [cfe] unspecified
  e0(x: 0);
}

enum E4({required covariant var int x}) {
//                          ^^^
// [analyzer] unspecified
// [cfe] unspecified
  e0(x: 0);
}

main() {
  print(E1);
  print(E2);
  print(E3);
  print(E4);
}