| // Copyright (c) 2019, 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. |
| |
| // Tests that short-circuit operators do not care about the unevaluated part. |
| |
| import "package:expect/expect.dart"; |
| |
| main() { |
| const C c = C(); |
| // Short-circuited operations. |
| // Non-taken branch of ?:. |
| const c1 = true ? c : c + c; |
| const c2 = false ? c + c : c; |
| // Non-taken part of &&, ||, ??. |
| const c3 = (c != null) || c < c; |
| const c4 = (c == null) && c < c; |
| const c5 = c ?? c + c; |
| Expect.identical(c, c1); |
| Expect.identical(c, c2); |
| Expect.isTrue(c3); |
| Expect.isFalse(c4); |
| Expect.identical(c, c5); |
| // Nested short-circuiting. |
| const c6 = true ? c == null && c + c : c < c; |
| Expect.isFalse(c6); |
| |
| // Concrete use-case. |
| Expect.equals(1, const T.length("a").value); |
| Expect.equals(0, const T.length("").value); |
| Expect.equals(0, const T.length(null).value); |
| Expect.equals(1, T.length([1]).value); |
| Expect.equals(0, T.length([]).value); |
| Expect.equals(0, T.length(null).value); |
| |
| Expect.equals(1, const T.asserts("a").value); |
| Expect.equals(0, const T.asserts("").value); |
| Expect.equals(0, const T.asserts(null).value); |
| Expect.equals(1, T.asserts([1]).value); |
| Expect.equals(0, T.asserts([]).value); |
| Expect.equals(0, T.asserts(null).value); |
| } |
| |
| class T { |
| final Object value; |
| const T(this.value); |
| const T.length(dynamic l) : value = (l == null ? 0 : l.length); |
| const T.asserts(dynamic l) |
| : assert(l == null || l.length < 2), |
| value = (l ?? "").length; |
| } |
| |
| class C { |
| const C(); |
| dynamic operator +(dynamic other) => throw "Never"; |
| bool operator <(dynamic other) => throw "Never"; |
| } |