| // 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 the static type of a ??= b is the least upper bound of the |
| // static types of a and b. |
| |
| import "package:expect/expect.dart"; |
| |
| bad() { |
| Expect.fail('Should not be executed'); |
| } |
| |
| /// Actually of type B so that the implicit downcasts below succeed at runtime. |
| A theA = new B(); |
| B theB = new B(); |
| |
| class A { |
| String a; |
| } |
| |
| class B extends A { |
| String b; |
| } |
| |
| class C extends A { |
| String c; |
| } |
| |
| A get a => null; |
| |
| void set a(A value) {} |
| |
| B get b => null; |
| |
| void set b(B value) {} |
| |
| class ClassWithStaticGetters { |
| static A get a => null; |
| |
| static void set a(A value) {} |
| |
| static B get b => null; |
| |
| static void set b(B value) {} |
| } |
| |
| class ClassWithInstanceGetters { |
| A get a => null; |
| |
| void set a(A value) {} |
| |
| B get b => null; |
| |
| void set b(B value) {} |
| } |
| |
| class DerivedClass extends ClassWithInstanceGetters { |
| A get a => bad(); |
| |
| void set a(A value) { |
| bad(); |
| } |
| |
| B get b => bad(); |
| |
| void set b(B value) { |
| bad(); |
| } |
| |
| void derivedTest() { |
| // The static type of super.v ??= e is the LUB of the static types of |
| // super.v and e. |
| (super.a ??= theA).a; //# 01: ok |
| (super.a ??= theA).b; //# 02: compile-time error |
| (super.a ??= theB).a; //# 03: ok |
| (super.a ??= theB).b; //# 04: compile-time error |
| (super.b ??= theA).a; //# 05: ok |
| (super.b ??= theA).b; //# 06: compile-time error |
| |
| // Exactly the same static errors that would be caused by super.v = e |
| // are also generated in the case of super.v ??= e. |
| super.b ??= new C(); //# 07: compile-time error |
| } |
| } |
| |
| main() { |
| new DerivedClass().derivedTest(); |
| |
| // The static type of v ??= e is the LUB of the static types of v and e. |
| (a ??= theA).a; //# 08: ok |
| (a ??= theA).b; //# 09: compile-time error |
| (a ??= theB).a; //# 10: ok |
| (a ??= theB).b; //# 11: compile-time error |
| (b ??= theA).a; //# 12: ok |
| (b ??= theA).b; //# 13: compile-time error |
| |
| // Exactly the same static errors that would be caused by v = e are also |
| // generated in the case of v ??= e. |
| b ??= new C(); //# 14: compile-time error |
| |
| // The static type of C.v ??= e is the LUB of the static types of C.v and e. |
| (ClassWithStaticGetters.a ??= theA).a; //# 15: ok |
| (ClassWithStaticGetters.a ??= theA).b; //# 16: compile-time error |
| (ClassWithStaticGetters.a ??= theB).a; //# 17: ok |
| (ClassWithStaticGetters.a ??= theB).b; //# 18: compile-time error |
| (ClassWithStaticGetters.b ??= theA).a; //# 19: ok |
| (ClassWithStaticGetters.b ??= theA).b; //# 20: compile-time error |
| |
| // Exactly the same static errors that would be caused by C.v = e are |
| // also generated in the case of C.v ??= e. |
| ClassWithStaticGetters.b ??= new C(); //# 21: compile-time error |
| |
| // The static type of e1.v ??= e2 is the LUB of the static types of e1.v and |
| // e2. |
| (new ClassWithInstanceGetters().a ??= theA).a; //# 22: ok |
| (new ClassWithInstanceGetters().a ??= theA).b; //# 23: compile-time error |
| (new ClassWithInstanceGetters().a ??= theB).a; //# 24: ok |
| (new ClassWithInstanceGetters().a ??= theB).b; //# 25: compile-time error |
| (new ClassWithInstanceGetters().b ??= theA).a; //# 26: ok |
| (new ClassWithInstanceGetters().b ??= theA).b; //# 27: compile-time error |
| |
| // Exactly the same static errors that would be caused by e1.v = e2 are |
| // also generated in the case of e1.v ??= e2. |
| new ClassWithInstanceGetters().b ??= new C(); //# 28: compile-time error |
| |
| // The static type of e1[e2] ??= e3 is the LUB of the static types of e1[e2] |
| // and e3. |
| ((<A>[null])[0] ??= theA).a; //# 29: ok |
| ((<A>[null])[0] ??= theA).b; //# 30: compile-time error |
| ((<A>[null])[0] ??= theB).a; //# 31: ok |
| ((<A>[null])[0] ??= theB).b; //# 32: compile-time error |
| ((<B>[null])[0] ??= theA).a; //# 33: ok |
| ((<B>[null])[0] ??= theA).b; //# 34: compile-time error |
| |
| // Exactly the same static errors that would be caused by e1[e2] = e3 are |
| // also generated in the case of e1[e2] ??= e3. |
| (<B>[null])[0] ??= new C(); //# 35: compile-time error |
| |
| // The static type of e1?.v op= e2 is the static type of e1.v op e2, |
| // therefore the static type of e1?.v ??= e2 is the static type of |
| // e1.v ?? e2, which is the LUB of the static types of e1?.v and e2. |
| (new ClassWithInstanceGetters()?.a ??= theA).a; //# 36: ok |
| (new ClassWithInstanceGetters()?.a ??= theA).b; //# 37: compile-time error |
| (new ClassWithInstanceGetters()?.a ??= theB).a; //# 38: ok |
| (new ClassWithInstanceGetters()?.a ??= theB).b; //# 39: compile-time error |
| (new ClassWithInstanceGetters()?.b ??= theA).a; //# 40: ok |
| (new ClassWithInstanceGetters()?.b ??= theA).b; //# 41: compile-time error |
| |
| // Exactly the same static errors that would be caused by e1.v ??= e2 are |
| // also generated in the case of e1?.v ??= e2. |
| new ClassWithInstanceGetters()?.b ??= new C(); //# 42: compile-time error |
| } |