| // Copyright (c) 2015, 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. |
| |
| // @dart = 2.9 |
| |
| // Verify that '??' binds tighter than '?:' and less tightly than '||'. |
| |
| import "package:expect/expect.dart"; |
| |
| main() { |
| // Make sure the "none" test fails if "??" is not implemented. This makes |
| // status files easier to maintain. |
| var _ = null ?? null; |
| |
| // "a ?? b ?? c" should be legal, and should evaluate to the first non-null |
| // value (or null if there are no non-null values). |
| Expect.equals(1, 1 ?? 2 ?? 3); |
| Expect.equals(2, null ?? 2 ?? 3); |
| Expect.equals(3, null ?? null ?? 3); |
| Expect.equals(null, null ?? null ?? null); |
| |
| // "a ?? b ? c : d" should parse as "(a ?? b) ? c : d", therefore provided |
| // that a is true, b need not be a bool. An incorrect parse of |
| // "a ?? (b ? c : d)" would require b to be a bool to avoid a static type |
| // warning. |
| Expect.equals(2, true ?? 1 ? 2 : 3); |
| |
| // "a ?? b || c" should parse as "a ?? (b || c)", therefore it's a static |
| // type warning if b doesn't have type bool. An incorrect parse of |
| // "(a ?? b) || c" would allow b to have any type provided that a is bool. |
| false ?? 1 || true; |
| // ^ |
| // [analyzer] COMPILE_TIME_ERROR.NON_BOOL_OPERAND |
| // [cfe] A value of type 'int' can't be assigned to a variable of type 'bool'. |
| |
| // "a || b ?? c" should parse as "(a || b) ?? c", therefore it is a static |
| // type warning if b doesn't have type bool. An incorrect parse of |
| // "a || (b ?? c)" would allow b to have any type provided that c is bool. |
| false || 1 ?? true; |
| // ^ |
| // [analyzer] COMPILE_TIME_ERROR.NON_BOOL_OPERAND |
| // [cfe] A value of type 'int' can't be assigned to a variable of type 'bool'. |
| |
| // An incorrect parse of "a || (b ?? c)" would result in no checked-mode |
| // error. |
| Expect.throwsAssertionError(() => false || null ?? true); |
| } |