Migrate block 116.

tests/language/if_null_assignment_static_test.dart

-// 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.
-
-// 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";
-
-// Determine whether the VM is running in checked mode.
-bool get checkedMode {
-  try {
-    var x = 'foo';
-    int y = x;
-    return false;
-  } catch (_) {
-    return true;
-  }
-}
-
-noMethod(e) => e is NoSuchMethodError;
-
-bad() {
-  Expect.fail('Should not be executed');
-}
-
-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 {
-  dynamic get a => bad();
-
-  void set a(dynamic value) {
-    bad();
-  }
-
-  dynamic get b => bad();
-
-  void set b(dynamic 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 ??= new A()).a; //# 01: ok
-    Expect.throws(() => (super.a ??= new A()).b, noMethod); //# 02: static type warning
-    (super.a ??= new B()).a; //# 03: ok
-    (super.a ??= new B()).b; //# 04: static type warning
-    if (!checkedMode) {
-      (super.b ??= new A()).a; //# 05: ok
-      Expect.throws(() => (super.b ??= new A()).b, noMethod); //# 06: static type warning
-
-      // Exactly the same static warnings that would be caused by super.v = e
-      // are also generated in the case of super.v ??= e.
-      super.b ??= new C(); //# 07: static type warning
-    }
-  }
-}
-
-main() {
-  // Make sure the "none" test fails if "??=" is not implemented.  This makes
-  // status files easier to maintain.
-  var _;
-  _ ??= null;
-
-  new DerivedClass().derivedTest();
-
-  // The static type of v ??= e is the LUB of the static types of v and e.
-  (a ??= new A()).a; //# 08: ok
-  Expect.throws(() => (a ??= new A()).b, noMethod); //# 09: static type warning
-  (a ??= new B()).a; //# 10: ok
-  (a ??= new B()).b; //# 11: static type warning
-  if (!checkedMode) {
-    (b ??= new A()).a; //# 12: ok
-    Expect.throws(() => (b ??= new A()).b, noMethod); //# 13: static type warning
-
-    // Exactly the same static warnings that would be caused by v = e are also
-    // generated in the case of v ??= e.
-    b ??= new C(); //# 14: static type warning
-  }
-
-  // The static type of C.v ??= e is the LUB of the static types of C.v and e.
-  (ClassWithStaticGetters.a ??= new A()).a; //# 15: ok
-  Expect.throws(() => (ClassWithStaticGetters.a ??= new A()).b, noMethod); //# 16: static type warning
-  (ClassWithStaticGetters.a ??= new B()).a; //# 17: ok
-  (ClassWithStaticGetters.a ??= new B()).b; //# 18: static type warning
-  if (!checkedMode) {
-    (ClassWithStaticGetters.b ??= new A()).a; //# 19: ok
-    Expect.throws(() => (ClassWithStaticGetters.b ??= new A()).b, noMethod); //# 20: static type warning
-
-    // Exactly the same static warnings that would be caused by C.v = e are
-    // also generated in the case of C.v ??= e.
-    ClassWithStaticGetters.b ??= new C(); //# 21: static type warning
-  }
-
-  // The static type of e1.v ??= e2 is the LUB of the static types of e1.v and
-  // e2.
-  (new ClassWithInstanceGetters().a ??= new A()).a; //# 22: ok
-  Expect.throws(() => (new ClassWithInstanceGetters().a ??= new A()).b, noMethod); //# 23: static type warning
-  (new ClassWithInstanceGetters().a ??= new B()).a; //# 24: ok
-  (new ClassWithInstanceGetters().a ??= new B()).b; //# 25: static type warning
-  if (!checkedMode) {
-    (new ClassWithInstanceGetters().b ??= new A()).a; //# 26: ok
-    Expect.throws(() => (new ClassWithInstanceGetters().b ??= new A()).b, noMethod); //# 27: static type warning
-
-    // Exactly the same static warnings that would be caused by e1.v = e2 are
-    // also generated in the case of e1.v ??= e2.
-    new ClassWithInstanceGetters().b ??= new C(); //# 28: static type warning
-  }
-
-  // The static type of e1[e2] ??= e3 is the LUB of the static types of e1[e2]
-  // and e3.
-  ((<A>[null])[0] ??= new A()).a; //# 29: ok
-  Expect.throws(() => ((<A>[null])[0] ??= new A()).b, noMethod); //# 30: static type warning
-  ((<A>[null])[0] ??= new B()).a; //# 31: ok
-  ((<A>[null])[0] ??= new B()).b; //# 32: static type warning
-  if (!checkedMode) {
-    ((<B>[null])[0] ??= new A()).a; //# 33: ok
-    Expect.throws(() => ((<B>[null])[0] ??= new A()).b, noMethod); //# 34: static type warning
-
-    // Exactly the same static warnings that would be caused by e1[e2] = e3 are
-    // also generated in the case of e1[e2] ??= e3.
-    (<B>[null])[0] ??= new C(); //# 35: static type warning
-  }
-
-  // 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 ??= new A()).a; //# 36: ok
-  Expect.throws(() => (new ClassWithInstanceGetters()?.a ??= new A()).b, noMethod); //# 37: static type warning
-  (new ClassWithInstanceGetters()?.a ??= new B()).a; //# 38: ok
-  (new ClassWithInstanceGetters()?.a ??= new B()).b; //# 39: static type warning
-  if (!checkedMode) {
-    (new ClassWithInstanceGetters()?.b ??= new A()).a; //# 40: ok
-    Expect.throws(() => (new ClassWithInstanceGetters()?.b ??= new A()).b, noMethod); //# 41: static type warning
-
-    // Exactly the same static warnings that would be caused by e1.v ??= e2 are
-    // also generated in the case of e1?.v ??= e2.
-    new ClassWithInstanceGetters()?.b ??= new C(); //# 42: static type warning
-  }
-}