| // 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 |
| /// listPattern ::= typeArguments? '[' listPatternElements? ']' |
| /// listPatternElements ::= listPatternElement ( ',' listPatternElement )* ','? |
| /// listPatternElement ::= pattern | restPattern |
| /// restPattern ::= '...' pattern? |
| /// |
| /// A list pattern may contain a rest element which allows matching lists of |
| /// arbitrary lengths. If a rest element is present and has a subpattern, all of |
| /// the elements not matched by other subpatterns are collected into a new list |
| /// and that list is matched against the rest subpattern. |
| /// |
| /// var [a, b, ...rest, c, d] = [1, 2, 3, 4, 5, 6, 7]; |
| /// print('$a $b $rest $c $d'); // Prints "1 2 [3, 4, 5] 6 7". |
| /// |
| /// @description Check that it is a static warning if null-check subpattern is |
| /// used in a list's rest pattern |
| /// @author sgrekhov22@gmail.com |
| |
| String test1(List list) { |
| return switch (list) { |
| <int>[1, 2, 3, 4, ... var r1?] => r1.toString(), |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| [2, ...final r2?, 5, 6] => r2.toString(), |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| <int>[.../* comment */ List r3?, 6, 7, 8] => r3.toString(), |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| _ => "default" |
| }; |
| } |
| |
| String test2(List list) { |
| switch (list) { |
| case <int>[1, 2, 3, 4, ... var r1?]: |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| return r1.toString(); |
| case [2, ...final r2?, 5, 6]: |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| return r2.toString(); |
| case <int>[... /* comment */ List r3?, 6, 7, 8]: |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| return r3.toString(); |
| default: |
| return "default"; |
| } |
| } |
| |
| String test3(List list) { |
| if (list case <int>[1, 2, 3, 4, ... var r1?]) { |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| return r1.toString(); |
| } |
| if (list case [2, ...final r2?, 5, 6]) { |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| return r2.toString(); |
| } |
| if (list case <int>[... /* comment */ List r3?, 6, 7, 8]) { |
| // ^ |
| // [analyzer] STATIC_WARNING.UNNECESSARY_NULL_CHECK_PATTERN |
| return r3.toString(); |
| } |
| return "default"; |
| } |
| |
| main() { |
| test1([1, 2, 3, 4, 5, 6]); |
| test2([1, 2, 3, 4, 5, 6]); |
| test3([1, 2, 3, 4, 5, 6]); |
| } |
