| // Copyright (c) 2024, 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 constantPattern ::= booleanLiteral |
| /// | nullLiteral |
| /// | '-'? numericLiteral |
| /// | stringLiteral |
| /// | symbolLiteral |
| /// | identifier |
| /// | qualifiedName |
| /// | constObjectExpression |
| /// | 'const' typeArguments? '[' elements? ']' |
| /// | 'const' typeArguments? '{' elements? '}' |
| /// | 'const' '(' expression ')' |
| /// |
| /// A constant pattern determines if the matched value is equal to the |
| /// constant's value. We don't allow all expressions here because many |
| /// expression forms syntactically overlap other kinds of patterns. We avoid |
| /// ambiguity while supporting terse forms of the most common constant |
| /// expressions like so: |
| /// ... |
| /// It is a compile-time error if a constant pattern's value is not a valid |
| /// constant expression. |
| /// |
| /// @description Check that it is a compile-time error if a constant pattern's |
| /// value is not a valid constant expression. Test switch expression |
| /// @author sgrekhov22@gmail.com |
| |
| extension type NumET(num n) implements num {} |
| extension type const IntET(int i) implements int {} |
| |
| int test() { |
| Object value = Object(); |
| final v = IntET(0); |
| |
| return switch (value) { |
| v => 1, |
| // ^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| IntET(1) => 2, |
| // ^^^^^^^^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| v.i => 3, |
| // ^^^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| const NumET(4) => 4, |
| // ^^^^^^^^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| const (NumET(5).n) => 5, |
| // ^^^^^^^^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| _ => -1 |
| }; |
| } |
| |
| main() { |
| test(); |
| } |
