LanguageFeatures/Patterns/variable_A03_t04.dart

// Copyright (c) 2022, 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
/// variablePattern ::= ( 'var' | 'final' | 'final'? type )? identifier
///
/// A variable pattern binds the matched value to a new variable. These usually
/// occur as subpatterns of a destructuring pattern in order to capture a
/// destructured value.
/// ```dart
/// var (a, b) = (1, 2);
/// ```
/// Here, a and b are variable patterns and end up bound to 1 and 2,
/// respectively.
///
/// The pattern may have a type annotation in order to only match values of the
/// specified type. If the type annotation is omitted, the variable's type is
/// inferred and the pattern matches all values.
/// ```dart
/// switch (record) {
///   case (int x, String s):
///     print('First field is int $x and second is String $s.');
/// }
/// ```
/// @description Check that if variable in a variable pattern is declared final
/// then it is a compile-time error to assign a value to it. Test maps
/// @author sgrekhov22@gmail.com

void test1(Map m) {
  switch (m) {
    case {1: final a}:
      a = 1;
//    ^
// [analyzer] unspecified
// [cfe] unspecified
      break;
    case {2: final String b}:
      b = "";
//    ^
// [analyzer] unspecified
// [cfe] unspecified
    break;
    case {3: final String? f}:
      c = "";
//    ^
// [analyzer] unspecified
// [cfe] unspecified
      break;
  }
}

Object? test2(Map m) {
  return switch (m) {
    {1: final a} => a = 1,
//                  ^
// [analyzer] unspecified
// [cfe] unspecified
    {2: final String b} => b = "",
//                         ^
// [analyzer] unspecified
// [cfe] unspecified
    {3: final String? f} => c = "",
//                          ^
// [analyzer] unspecified
// [cfe] unspecified
    _ => ""
  };
}

void test3(Map m) {
  if (m case {1: final a}) {
    a = 1;
//    ^
// [analyzer] unspecified
// [cfe] unspecified
  }
  if (m case {2: final String b}) {
    b = "";
//  ^
// [analyzer] unspecified
// [cfe] unspecified
  }
  if (m case {3: final String? f}) {
    c = "";
//  ^
// [analyzer] unspecified
// [cfe] unspecified
  }
}

main() {
  test1({});
  test2({});
  test3({});
}