| // 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 We extend switch statements to allow patterns in cases: |
| /// |
| /// switchStatement ::= 'switch' '(' expression ')' |
| /// '{' switchStatementCase* switchStatementDefault? '}' |
| /// switchStatementCase ::= label* 'case' guardedPattern ':' statements |
| /// guardedPattern ::= pattern ( 'when' expression )? |
| /// switchStatementDefault ::= label* 'default' ':' statements |
| /// ... |
| /// Many constant expressions are subsumed by the new pattern syntax so most |
| /// existing switch cases have the same semantics under this proposal. However, |
| /// patterns are not a strict superset of constant expressions and some switches |
| /// may be broken. |
| /// ... |
| /// Other constant expressions. Constant patterns allow simple literals and |
| /// references to named constants to be used directly as patterns, which covers |
| /// the majority of all existing switch cases. Also a constant constructor |
| /// explicitly prefixed with const is a valid constant expression pattern. But |
| /// some more complex expressions are valid constant expressions but not valid |
| /// constant patterns. |
| /// |
| /// @description Check that binary operator expressions derived from |
| /// `bitwiseOrExpression` are not valid in a `guardedPattern` and produce a |
| /// compile-time error. Test a library prefix. |
| /// @author sgrekhov22@gmail.com |
| /// @issue 63356 |
| |
| const a = 1; |
| const b = 2; |
