Migrate block 116.

tests/language_strong/if_null_assignment_behavior_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 semantics of the ??= operator, including order of operations, by
-// keeping track of the operations performed.
-
-import "package:expect/expect.dart";
-import "if_null_assignment_helper.dart" as h;
-
-bad() {
-  Expect.fail('Should not be executed');
-}
-
-var xGetValue = null;
-
-get x {
-  h.operations.add('x');
-  var tmp = xGetValue;
-  xGetValue = null;
-  return tmp;
-}
-
-void set x(value) {
-  h.operations.add('x=$value');
-}
-
-var yGetValue = null;
-
-get y {
-  h.operations.add('y');
-  var tmp = yGetValue;
-  yGetValue = null;
-  return tmp;
-}
-
-void set y(value) {
-  h.operations.add('y=$value');
-}
-
-var zGetValue = null;
-
-get z {
-  h.operations.add('z');
-  var tmp = zGetValue;
-  zGetValue = null;
-  return tmp;
-}
-
-void set z(value) {
-  h.operations.add('z=$value');
-}
-
-var fValue = null;
-
-f() {
-  h.operations.add('f()');
-  var tmp = fValue;
-  fValue = null;
-  return tmp;
-}
-
-void check(expectedValue, f(), expectedOperations) {
-  Expect.equals(expectedValue, f());
-  Expect.listEquals(expectedOperations, h.operations);
-  h.operations = [];
-}
-
-void checkThrows(expectedException, f(), expectedOperations) {
-  Expect.throws(f, expectedException);
-  Expect.listEquals(expectedOperations, h.operations);
-  h.operations = [];
-}
-
-noMethod(e) => e is NoSuchMethodError;
-
-class C {
-  final String s;
-
-  C(this.s);
-
-  @override
-  String toString() => s;
-
-  static var xGetValue = null;
-
-  static get x {
-    h.operations.add('C.x');
-    var tmp = xGetValue;
-    xGetValue = null;
-    return tmp;
-  }
-
-  static void set x(value) {
-    h.operations.add('C.x=$value');
-  }
-
-  var vGetValue = null;
-
-  get v {
-    h.operations.add('$s.v');
-    var tmp = vGetValue;
-    vGetValue = null;
-    return tmp;
-  }
-
-  void set v(value) {
-    h.operations.add('$s.v=$value');
-  }
-
-  var indexGetValue = null;
-
-  operator [](index) {
-    h.operations.add('$s[$index]');
-    var tmp = indexGetValue;
-    indexGetValue = null;
-    return tmp;
-  }
-
-  void operator []=(index, value) {
-    h.operations.add('$s[$index]=$value');
-  }
-
-  final finalOne = 1;
-  final finalNull = null;
-
-  void instanceTest() {
-    // v ??= e is equivalent to ((x) => x == null ? v = e : x)(v)
-    vGetValue = 1; check(1, () => v ??= bad(), ['$s.v']); //# 01: ok
-    yGetValue = 1; check(1, () => v ??= y, ['$s.v', 'y', '$s.v=1']); //# 02: ok
-    check(1, () => finalOne ??= bad(), []); //# 03: static type warning
-    yGetValue = 1; checkThrows(noMethod, () => finalNull ??= y, ['y']); //# 04: static type warning
-  }
-}
-
-class D extends C {
-  D(String s) : super(s);
-
-  get v => bad();
-
-  void set v(value) {
-    bad();
-  }
-
-  void derivedInstanceTest() {
-    // super.v ??= e is equivalent to
-    // ((x) => x == null ? super.v = e : x)(super.v)
-    vGetValue = 1; check(1, () => super.v ??= bad(), ['$s.v']); //# 05: ok
-    yGetValue = 1; check(1, () => super.v ??= y, ['$s.v', 'y', '$s.v=1']); //# 06: ok
-  }
-}
-
-main() {
-  // Make sure the "none" test fails if "??=" is not implemented.  This makes
-  // status files easier to maintain.
-  var _;
-  _ ??= null;
-
-  new C('c').instanceTest();
-  new D('d').derivedInstanceTest();
-
-  // v ??= e is equivalent to ((x) => x == null ? v = e : x)(v)
-  xGetValue = 1; check(1, () => x ??= bad(), ['x']); //# 07: ok
-  yGetValue = 1; check(1, () => x ??= y, ['x', 'y', 'x=1']); //# 08: ok
-  h.xGetValue = 1; check(1, () => h.x ??= bad(), ['h.x']); //# 09: ok
-  yGetValue = 1; check(1, () => h.x ??= y, ['h.x', 'y', 'h.x=1']); //# 10: ok
-  { var l = 1; check(1, () => l ??= bad(), []); } //# 11: ok
-  { var l; yGetValue = 1; check(1, () => l ??= y, ['y']); Expect.equals(1, l); } //# 12: ok
-  { final l = 1; check(1, () => l ??= bad(), []); } //# 13: static type warning
-  { final l = null; yGetValue = 1; checkThrows(noMethod, () => l ??= y, ['y']); } //# 14: static type warning
-  check(C, () => C ??= bad(), []); //# 15: static type warning
-  h ??= null; //# 29: compile-time error
-  h[0] ??= null; //# 30: compile-time error
-
-  // C.v ??= e is equivalent to ((x) => x == null ? C.v = e : x)(C.v)
-  C.xGetValue = 1; check(1, () => C.x ??= bad(), ['C.x']); //# 16: ok
-  yGetValue = 1; check(1, () => C.x ??= y, ['C.x', 'y', 'C.x=1']); //# 17: ok
-  h.C.xGetValue = 1; check(1, () => h.C.x ??= bad(), ['h.C.x']); //# 18: ok
-  yGetValue = 1; check(1, () => h.C.x ??= y, ['h.C.x', 'y', 'h.C.x=1']); //# 19: ok
-
-  // e1.v ??= e2 is equivalent to
-  // ((x) => ((y) => y == null ? x.v = e2 : y)(x.v))(e1)
-  xGetValue = new C('x'); xGetValue.vGetValue = 1; //# 20: ok
-  check(1, () => x.v ??= bad(), ['x', 'x.v']); //    //# 20: continued
-  xGetValue = new C('x'); yGetValue = 1; //               //# 21: ok
-  check(1, () => x.v ??= y, ['x', 'x.v', 'y', 'x.v=1']); //# 21: continued
-  fValue = new C('f()'); fValue.vGetValue = 1; //      //# 22: ok
-  check(1, () => f().v ??= bad(), ['f()', 'f().v']); //# 22: continued
-  fValue = new C('f()'); yGetValue = 1; //                         //# 23: ok
-  check(1, () => f().v ??= y, ['f()', 'f().v', 'y', 'f().v=1']); //# 23: continued
-
-  // e1[e2] ??= e3 is equivalent to
-  // ((a, i) => ((x) => x == null ? a[i] = e3 : x)(a[i]))(e1, e2)
-  xGetValue = new C('x'); yGetValue = 1; xGetValue.indexGetValue = 2; //# 24: ok
-  check(2, () => x[y] ??= bad(), ['x', 'y', 'x[1]']); //                //# 24: continued
-  xGetValue = new C('x'); yGetValue = 1; zGetValue = 2; //         //# 25: ok
-  check(2, () => x[y] ??= z, ['x', 'y', 'x[1]', 'z', 'x[1]=2']); //# 25: continued
-
-  // e1?.v ??= e2 is equivalent to ((x) => x == null ? null : x.v ??= e2)(e1).
-  check(null, () => x?.v ??= bad(), ['x']); //# 26: ok
-  xGetValue = new C('x'); xGetValue.vGetValue = 1; //# 27: ok
-  check(1, () => x?.v ??= bad(), ['x', 'x.v']); //    //# 27: continued
-  xGetValue = new C('x'); yGetValue = 1; //                //# 28: ok
-  check(1, () => x?.v ??= y, ['x', 'x.v', 'y', 'x.v=1']); //# 28: continued
-
-  // C?.v ??= e2 is equivalent to C.v ??= e2.
-  C.xGetValue = 1; //                        //# 29: ok
-  check(1, () => C?.x ??= bad(), ['C.x']); //# 29: continued
-  h.C.xgetValue = 1; //                          //# 30: ok
-  check(1, () => h.c?.x ??= bad(), ['h.C.x']); //# 30: continued
-  yGetValue = 1; //                                    //# 31: ok
-  check(1, () => C?.x ??= y, ['C.x', 'y', 'C.x=1']); //# 31: continued
-  yGetValue = 1; //                                          //# 32: ok
-  check(1, () => h.C?.x ??= y, ['h.C.x', 'y', 'h.C.x=1']); //# 32: continued
-}