Robert Nystrom
8f85a9efe4
Change-Id: I52dee4ed475611ce4ea5d0d45914717ff13f5b8b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/141768 Auto-Submit: Bob Nystrom <rnystrom@google.com> Reviewed-by: Leaf Petersen <leafp@google.com>
64 lines
2.0 KiB
Dart
64 lines
2.0 KiB
Dart
// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Tests that equality is allowed for receivers of specific types.
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import "package:expect/expect.dart";
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main() {
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const c = C(); // Does not override operator==.
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const d = D(); // Overrides operator==.
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// Allowed if receiver is int, double, String, bool or Null, ...
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Expect.isTrue(const T.eq(1, 1).value);
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Expect.isTrue(const T.eq(1.5, 1.5).value);
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Expect.isTrue(const T.eq("", "").value);
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Expect.isTrue(const T.eq(true, true).value);
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Expect.isTrue(const T.eq(null, null).value);
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Expect.isFalse(const T.eq(1, c).value);
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Expect.isFalse(const T.eq(1.5, c).value);
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Expect.isFalse(const T.eq("", c).value);
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Expect.isFalse(const T.eq(true, c).value);
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Expect.isFalse(const T.eq(null, c).value);
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Expect.isFalse(const T.eq(1, d).value);
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Expect.isFalse(const T.eq(1.5, d).value);
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Expect.isFalse(const T.eq("", d).value);
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Expect.isFalse(const T.eq(true, d).value);
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Expect.isFalse(const T.eq(null, d).value);
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// ... or if second operand is Null.
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Expect.isFalse(const T.eq(1, null).value);
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Expect.isFalse(const T.eq(1.5, null).value);
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Expect.isFalse(const T.eq("", null).value);
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Expect.isFalse(const T.eq(false, null).value);
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Expect.isFalse(const T.eq(c, null).value);
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Expect.isFalse(const T.eq(d, null).value);
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// Otherwise not allowed.
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const T.eq(c, c); //# 01: compile-time error
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const T.eq(c, 1); //# 02: compile-time error
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const T.eq(c, ""); //# 03: compile-time error
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const T.eq(E.value1, E.value2); //# 04: compile-time error
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}
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class T {
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final Object value;
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const T.eq(Object? o1, Object? o2) : value = o1 == o2;
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}
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/// Class that does not override operator==.
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class C {
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const C();
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}
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/// Class that overrides operator==.
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class D {
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const D();
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bool operator ==(Object other) => identical(this, other);
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}
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enum E { value1, value2 }
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