blob: 020b988607d6567c1f92f5709d99c391c8d506d1 [file] [log] [blame]
// 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
}