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1 // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 // Evaluation of an if-null expresion e of the form e1 ?? e2 is equivalent to | 5 // Evaluation of an if-null expresion e of the form e1 ?? e2 is equivalent to |
6 // the evaluation of the expression ((x) => x == null ? e2 : x)(e1). The | 6 // the evaluation of the expression ((x) => x == null ? e2 : x)(e1). The |
7 // static type of e is the least upper bound of the static type of e1 and the | 7 // static type of e is the least upper bound of the static type of e1 and the |
8 // static type of e2. | 8 // static type of e2. |
9 | 9 |
10 import "package:expect/expect.dart"; | 10 import "package:expect/expect.dart"; |
11 | 11 |
12 class A { | 12 class A { |
13 final String a; | 13 final String a; |
14 A(this.a); | 14 A(this.a); |
15 } | 15 } |
16 | 16 |
17 class B extends A { | 17 class B extends A { |
18 B(String v) | 18 B(String v) : b = v, super(v); |
19 : b = v, | |
20 super(v); | |
21 final String b; | 19 final String b; |
22 } | 20 } |
23 | 21 |
24 class C extends A { | 22 class C extends A { |
25 C(String v) | 23 C(String v) : c = v, super(v); |
26 : c = v, | |
27 super(v); | |
28 final String c; | 24 final String c; |
29 } | 25 } |
30 | 26 |
31 B nullB() => null; | 27 B nullB() => null; |
32 C nullC() => null; | 28 C nullC() => null; |
33 | 29 |
34 noMethod(e) => e is NoSuchMethodError; | 30 noMethod(e) => e is NoSuchMethodError; |
35 | 31 |
36 main() { | 32 main() { |
37 // Make sure the "none" test fails if "??" is not implemented. This makes | 33 // Make sure the "none" test fails if "??" is not implemented. This makes |
(...skipping 10 matching lines...) Expand all Loading... |
48 Expect.equals('B', (new B('B') ?? nullC()).a); //# 08: ok | 44 Expect.equals('B', (new B('B') ?? nullC()).a); //# 08: ok |
49 Expect.equals('B', (new B('B') ?? nullC()).b); //# 09: static type warning | 45 Expect.equals('B', (new B('B') ?? nullC()).b); //# 09: static type warning |
50 Expect.throws(() => (new B('B') ?? nullC()).c, noMethod); //# 10: static type
warning | 46 Expect.throws(() => (new B('B') ?? nullC()).c, noMethod); //# 10: static type
warning |
51 Expect.equals('C', (nullB() ?? new C('C')).a); //# 11: ok | 47 Expect.equals('C', (nullB() ?? new C('C')).a); //# 11: ok |
52 Expect.throws(() => (nullB() ?? new C('C')).b, noMethod); //# 12: static type
warning | 48 Expect.throws(() => (nullB() ?? new C('C')).b, noMethod); //# 12: static type
warning |
53 Expect.equals('C', (nullB() ?? new C('C')).c); //# 13: static type warning | 49 Expect.equals('C', (nullB() ?? new C('C')).c); //# 13: static type warning |
54 Expect.throws(() => (nullB() ?? nullC()).a, noMethod); //# 14: ok | 50 Expect.throws(() => (nullB() ?? nullC()).a, noMethod); //# 14: ok |
55 Expect.throws(() => (nullB() ?? nullC()).b, noMethod); //# 15: static type war
ning | 51 Expect.throws(() => (nullB() ?? nullC()).b, noMethod); //# 15: static type war
ning |
56 Expect.throws(() => (nullB() ?? nullC()).c, noMethod); //# 16: static type war
ning | 52 Expect.throws(() => (nullB() ?? nullC()).c, noMethod); //# 16: static type war
ning |
57 } | 53 } |
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