LanguageFeatures/Primary-constructors/static_processing_A21_t08.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 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 a formal parameter of the form `var T p` where `T`
/// is a type and `p` is an identifier is replaced in `L2` by `this.p`
/// and a semantic instance variable declaration corresponding to the syntax
/// `T p;` (without `final`) is added to `D2`. Test required named parameters.
/// @author sgrekhov22@gmail.com

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

import '../../Utils/expect.dart';

class C1<T>({required var T v});

class C2({required var int v});

main() {
  var c1 = C1<int>(v: 1);
  Expect.equals(1, c1.v);
  c1.v = 2;
  Expect.equals(2, c1.v);

  var c2 = C2(v: 1);
  Expect.equals(1, c2.v);
  c2.v = 2;
  Expect.equals(2, c2.v);
}