Bug 1204028: Evaluate LHS reference before RHS in destructuring

Issue #73
[Depends on] Bug 1147371: Implement IteratorClose

2 files changed, 1472 insertions, 0 deletions

diff --git a/js/src/tests/ecma_6/Destructuring/order-super.js b/js/src/tests/ecma_6/Destructuring/order-super.js
new file mode 100644
index 0000000000..afe11e2d91
--- /dev/null
+++ b/js/src/tests/ecma_6/Destructuring/order-super.js
@@ -0,0 +1,727 @@
+var BUGNUMBER = 1204028;
+var summary = "Destructuring should evaluate lhs reference before rhs in super property";
+
+if (typeof assertEq === "undefined") {
+  assertEq = function(a, b) {
+    if (a !== b)
+      throw new Error(`expected ${b}, got ${a}\n${new Error().stack}`);
+  };
+}
+
+print(BUGNUMBER + ": " + summary);
+
+let logs = [];
+function log(x) {
+  logs.push(x);
+}
+
+let unwrapMap = new Map();
+function unwrap(maybeWrapped) {
+  if (unwrapMap.has(maybeWrapped))
+    return unwrapMap.get(maybeWrapped);
+  return maybeWrapped;
+}
+function ToString(name) {
+  if (name == Symbol.iterator)
+    return "@@iterator";
+  return String(name);
+}
+function logger(obj, prefix=[]) {
+  let wrapped = new Proxy(obj, {
+    get(that, name) {
+      if (name == "return") {
+        // FIXME: Bug 1147371.
+        // We ignore IteratorClose for now.
+        return obj[name];
+      }
+
+      let names = prefix.concat(ToString(name));
+      log("rhs get " + names.join("::"));
+      let v = obj[name];
+      if (typeof v === "object" || typeof v === "function")
+        return logger(v, names);
+      return v;
+    },
+    apply(that, thisArg, args) {
+      let names = prefix.slice();
+      log("rhs call " + names.join("::"));
+      let v = obj.apply(unwrap(thisArg), args);
+      if (typeof v === "object" || typeof v === "function") {
+        names[names.length - 1] += "()";
+        return logger(v, names);
+      }
+      return v;
+    }
+  });
+  unwrapMap.set(wrapped, obj);
+  return wrapped;
+}
+
+class C1 {
+  constructor() {
+    this.clear();
+  }
+  clear() {
+    this.values = {};
+  }
+}
+for (let name of [
+  "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m",
+  "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z",
+  "0", "1", "length"
+]) {
+  Object.defineProperty(C1.prototype, name, {
+    set: function(value) {
+      log("lhs set " + name);
+      this.values[name] = value;
+    }
+  });
+}
+class C2 extends C1 {
+  constructor() {
+    super();
+
+    let clear = () => {
+      logs = [];
+      this.clear();
+    };
+
+    // Array.
+
+    clear();
+    [
+      super.a
+    ] = logger(["A"]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "lhs set a",
+             ].join(","));
+    assertEq(this.values.a, "A");
+
+    clear();
+    [
+      super[ (log("lhs before name a"), "a") ]
+    ] = logger(["A"]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "lhs before name a",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "lhs set a",
+             ].join(","));
+    assertEq(this.values.a, "A");
+
+    // Array rest.
+
+    clear();
+    [
+      ...super.a
+    ] = logger(["A", "B", "C"]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "lhs set a",
+             ].join(","));
+    assertEq(this.values.a.join(","), "A,B,C");
+
+    clear();
+    [
+      ...super[ (log("lhs before name a"), "a") ]
+    ] = logger(["A", "B", "C"]);;
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "lhs before name a",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "lhs set a",
+             ].join(","));
+    assertEq(this.values.a.join(","), "A,B,C");
+
+    // Array combined.
+
+    clear();
+    [
+      super.a,
+      super[ (log("lhs before name b"), "b") ],
+      ...super[ (log("lhs before name c"), "c") ]
+    ] = logger(["A", "B", "C"]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "lhs set a",
+
+               "lhs before name b",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "lhs set b",
+
+               "lhs before name c",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "lhs set c",
+             ].join(","));
+    assertEq(this.values.a, "A");
+    assertEq(this.values.b, "B");
+    assertEq(this.values.c.join(","), "C");
+
+    // Object.
+
+    clear();
+    ({
+      a: super.a
+    } = logger({a: "A"}));
+    assertEq(logs.join(","),
+             [
+               "rhs get a",
+               "lhs set a",
+             ].join(","));
+    assertEq(this.values.a, "A");
+
+    clear();
+    ({
+      a: super[ (log("lhs before name a"), "a") ]
+    } = logger({a: "A"}));
+    assertEq(logs.join(","),
+             [
+               "lhs before name a",
+               "rhs get a",
+               "lhs set a",
+             ].join(","));
+    assertEq(this.values.a, "A");
+
+    // Object combined.
+
+    clear();
+    ({
+      a: super.a,
+      b: super[ (log("lhs before name b"), "b") ]
+    } = logger({a: "A", b: "B"}));
+    assertEq(logs.join(","),
+             [
+               "rhs get a",
+               "lhs set a",
+
+               "lhs before name b",
+               "rhs get b",
+               "lhs set b",
+             ].join(","));
+    assertEq(this.values.a, "A");
+    assertEq(this.values.b, "B");
+
+    // == Nested ==
+
+    // Array -> Array
+
+    clear();
+    [
+      [
+        super[ (log("lhs before name a"), "a") ],
+        ...super[ (log("lhs before name b"), "b") ]
+      ]
+    ] = logger([["A", "B"]]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next()::value::@@iterator",
+               "rhs call @@iterator()::next()::value::@@iterator",
+
+               "lhs before name a",
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+               "lhs set a",
+
+               "lhs before name b",
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "lhs set b",
+             ].join(","));
+    assertEq(this.values.a, "A");
+    assertEq(this.values.b.length, 1);
+    assertEq(this.values.b[0], "B");
+
+    // Array rest -> Array
+
+    clear();
+    [
+      ...[
+        super[ (log("lhs before name a"), "a") ],
+        ...super[ (log("lhs before name b"), "b") ]
+      ]
+    ] = logger(["A", "B"]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+
+               "lhs before name a",
+               "lhs set a",
+
+               "lhs before name b",
+               "lhs set b",
+             ].join(","));
+    assertEq(this.values.a, "A");
+    assertEq(this.values.b.join(","), "B");
+
+    // Array -> Object
+    clear();
+    [
+      {
+        a: super[ (log("lhs before name a"), "a") ]
+      }
+    ] = logger([{a: "A"}]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+
+               "lhs before name a",
+               "rhs get @@iterator()::next()::value::a",
+               "lhs set a",
+             ].join(","));
+    assertEq(this.values.a, "A");
+
+    // Array rest -> Object
+    clear();
+    [
+      ...{
+        0: super[ (log("lhs before name 0"), "0") ],
+        1: super[ (log("lhs before name 1"), "1") ],
+        length: super[ (log("lhs before name length"), "length") ],
+      }
+    ] = logger(["A", "B"]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+
+               "lhs before name 0",
+               "lhs set 0",
+
+               "lhs before name 1",
+               "lhs set 1",
+
+               "lhs before name length",
+               "lhs set length",
+             ].join(","));
+    assertEq(this.values["0"], "A");
+    assertEq(this.values["1"], "B");
+    assertEq(this.values.length, 2);
+
+    // Object -> Array
+    clear();
+    ({
+      a: [
+        super[ (log("lhs before name b"), "b") ]
+      ]
+    } = logger({a: ["B"]}));
+    assertEq(logs.join(","),
+             [
+               "rhs get a",
+               "rhs get a::@@iterator",
+               "rhs call a::@@iterator",
+
+               "lhs before name b",
+               "rhs get a::@@iterator()::next",
+               "rhs call a::@@iterator()::next",
+               "rhs get a::@@iterator()::next()::done",
+               "rhs get a::@@iterator()::next()::value",
+               "lhs set b",
+             ].join(","));
+    assertEq(this.values.b, "B");
+
+    // Object -> Object
+    clear();
+    ({
+      a: {
+        b: super[ (log("lhs before name b"), "b") ]
+      }
+    } = logger({a: {b: "B"}}));
+    assertEq(logs.join(","),
+             [
+               "rhs get a",
+               "lhs before name b",
+               "rhs get a::b",
+               "lhs set b",
+             ].join(","));
+    assertEq(this.values.b, "B");
+
+    // All combined
+
+    clear();
+    [
+      super[ (log("lhs before name a"), "a") ],
+      [
+        super[ (log("lhs before name b"), "b") ],
+        {
+          c: super[ (log("lhs before name c"), "c") ],
+          d: {
+            e: super[ (log("lhs before name e"), "e") ],
+            f: [
+              super[ (log("lhs before name g"), "g") ]
+            ]
+          }
+        }
+      ],
+      {
+        h: super[ (log("lhs before name h"), "h") ],
+        i: [
+          super[ (log("lhs before name j"), "j") ],
+          {
+            k: [
+              super[ (log("lhs before name l"), "l") ]
+            ]
+          }
+        ]
+      },
+      ...[
+        super[ (log("lhs before name m"), "m") ],
+        [
+          super[ (log("lhs before name n"), "n") ],
+          {
+            o: super[ (log("lhs before name o"), "o") ],
+            p: {
+              q: super[ (log("lhs before name q"), "q") ],
+              r: [
+                super[ (log("lhs before name s"), "s") ]
+              ]
+            }
+          }
+        ],
+        ...{
+          0: super[ (log("lhs before name t"), "t") ],
+          1: [
+            super[ (log("lhs before name u"), "u") ],
+            {
+              v: super[ (log("lhs before name v"), "v") ],
+              w: {
+                x: super[ (log("lhs before name x"), "x") ],
+                y: [
+                  super[ (log("lhs before name z"), "z") ]
+                ]
+              }
+            }
+          ],
+          length: super[ (log("lhs before name length"), "length") ],
+        }
+      ]
+    ] = logger(["A",
+                ["B", {c: "C", d: {e: "E", f: ["G"]}}],
+                {h: "H", i: ["J", {k: ["L"]}]},
+                "M",
+                ["N", {o: "O", p: {q: "Q", r: ["S"]}}],
+                "T", ["U", {v: "V", w: {x: "X", y: ["Z"]}}]]);
+    assertEq(logs.join(","),
+             [
+               "rhs get @@iterator",
+               "rhs call @@iterator",
+
+               "lhs before name a",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "lhs set a",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next()::value::@@iterator",
+               "rhs call @@iterator()::next()::value::@@iterator",
+
+               "lhs before name b",
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+               "lhs set b",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+
+               "lhs before name c",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::c",
+               "lhs set c",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d",
+
+               "lhs before name e",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::e",
+               "lhs set e",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator",
+               "rhs call @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator",
+
+               "lhs before name g",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next()::value",
+               "lhs set g",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+
+               "lhs before name h",
+               "rhs get @@iterator()::next()::value::h",
+               "lhs set h",
+
+               "rhs get @@iterator()::next()::value::i",
+               "rhs get @@iterator()::next()::value::i::@@iterator",
+               "rhs call @@iterator()::next()::value::i::@@iterator",
+
+               "lhs before name j",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::i::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value",
+               "lhs set j",
+
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::i::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value",
+
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator",
+               "rhs call @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator",
+
+               "lhs before name l",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next()::value",
+               "lhs set l",
+
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value",
+               "rhs get @@iterator()::next",
+               "rhs call @@iterator()::next",
+               "rhs get @@iterator()::next()::done",
+
+               "lhs before name m",
+               "lhs set m",
+
+               "rhs get @@iterator()::next()::value::@@iterator",
+               "rhs call @@iterator()::next()::value::@@iterator",
+
+               "lhs before name n",
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+               "lhs set n",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+
+               "lhs before name o",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::o",
+               "lhs set o",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p",
+
+               "lhs before name q",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::q",
+               "lhs set q",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator",
+               "rhs call @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator",
+
+               "lhs before name s",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next()::value",
+               "lhs set s",
+
+               "lhs before name t",
+               "lhs set t",
+
+               "rhs get @@iterator()::next()::value::@@iterator",
+               "rhs call @@iterator()::next()::value::@@iterator",
+
+               "lhs before name u",
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+               "lhs set u",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+
+               "lhs before name v",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::v",
+               "lhs set v",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w",
+
+               "lhs before name x",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::x",
+               "lhs set x",
+
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator",
+               "rhs call @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator",
+
+               "lhs before name z",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next",
+               "rhs call @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next()::done",
+               "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next()::value",
+               "lhs set z",
+
+               "lhs before name length",
+               "lhs set length",
+             ].join(","));
+    assertEq(this.values.a, "A");
+    assertEq(this.values.b, "B");
+    assertEq(this.values.c, "C");
+    assertEq(this.values.e, "E");
+    assertEq(this.values.g, "G");
+    assertEq(this.values.h, "H");
+    assertEq(this.values.j, "J");
+    assertEq(this.values.l, "L");
+    assertEq(this.values.m, "M");
+    assertEq(this.values.n, "N");
+    assertEq(this.values.o, "O");
+    assertEq(this.values.q, "Q");
+    assertEq(this.values.s, "S");
+    assertEq(this.values.t, "T");
+    assertEq(this.values.u, "U");
+    assertEq(this.values.v, "V");
+    assertEq(this.values.x, "X");
+    assertEq(this.values.z, "Z");
+    assertEq(this.values.length, 2);
+  }
+}
+
+new C2();
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/ecma_6/Destructuring/order.js b/js/src/tests/ecma_6/Destructuring/order.js
new file mode 100644
index 0000000000..4eb48cd2b0
--- /dev/null
+++ b/js/src/tests/ecma_6/Destructuring/order.js
@@ -0,0 +1,745 @@
+var BUGNUMBER = 1204028;
+var summary = "Destructuring should evaluate lhs reference before rhs";
+
+print(BUGNUMBER + ": " + summary);
+
+let storage = {
+  clear() {
+    this.values = {};
+  }
+};
+storage.clear();
+let obj = new Proxy(storage, {
+  set(that, name, value) {
+    log("lhs set " + name);
+    storage.values[name] = value;
+  }
+});
+
+let logs = [];
+function log(x) {
+  logs.push(x);
+}
+
+function clear() {
+  logs = [];
+  storage.clear();
+}
+
+let unwrapMap = new Map();
+function unwrap(maybeWrapped) {
+  if (unwrapMap.has(maybeWrapped))
+    return unwrapMap.get(maybeWrapped);
+  return maybeWrapped;
+}
+function ToString(name) {
+  if (name == Symbol.iterator)
+    return "@@iterator";
+  return String(name);
+}
+function logger(obj, prefix=[]) {
+  let wrapped = new Proxy(obj, {
+    get(that, name) {
+      if (name == "return") {
+        // FIXME: Bug 1147371.
+        // We ignore IteratorClose for now.
+        return obj[name];
+      }
+
+      let names = prefix.concat(ToString(name));
+      log("rhs get " + names.join("::"));
+      let v = obj[name];
+      if (typeof v === "object" || typeof v === "function")
+        return logger(v, names);
+      return v;
+    },
+    apply(that, thisArg, args) {
+      let names = prefix.slice();
+      log("rhs call " + names.join("::"));
+      let v = obj.apply(unwrap(thisArg), args);
+      if (typeof v === "object" || typeof v === "function") {
+        names[names.length - 1] += "()";
+        return logger(v, names);
+      }
+      return v;
+    }
+  });
+  unwrapMap.set(wrapped, obj);
+  return wrapped;
+}
+
+// Array.
+
+clear();
+[
+  ( log("lhs before obj a"), obj ).a
+] = logger(["A"]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "lhs before obj a",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "lhs set a",
+         ].join(","));
+assertEq(storage.values.a, "A");
+
+clear();
+[
+  ( log("lhs before obj a"), obj )[ (log("lhs before name a"), "a") ]
+] = logger(["A"]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "lhs before obj a",
+           "lhs before name a",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "lhs set a",
+         ].join(","));
+assertEq(storage.values.a, "A");
+
+// Array rest.
+
+clear();
+[
+  ...( log("lhs before obj a"), obj ).a
+] = logger(["A", "B", "C"]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "lhs before obj a",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "lhs set a",
+         ].join(","));
+assertEq(storage.values.a.join(","), "A,B,C");
+
+clear();
+[
+  ...( log("lhs before obj a"), obj )[ (log("lhs before name a"), "a") ]
+] = logger(["A", "B", "C"]);;
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "lhs before obj a",
+           "lhs before name a",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "lhs set a",
+         ].join(","));
+assertEq(storage.values.a.join(","), "A,B,C");
+
+// Array combined.
+
+clear();
+[
+  ( log("lhs before obj a"), obj ).a,
+  ( log("lhs before obj b"), obj )[ (log("lhs before name b"), "b") ],
+  ...( log("lhs before obj c"), obj )[ (log("lhs before name c"), "c") ]
+] = logger(["A", "B", "C"]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "lhs before obj a",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "lhs set a",
+
+           "lhs before obj b",
+           "lhs before name b",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "lhs set b",
+
+           "lhs before obj c",
+           "lhs before name c",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "lhs set c",
+         ].join(","));
+assertEq(storage.values.a, "A");
+assertEq(storage.values.b, "B");
+assertEq(storage.values.c.join(","), "C");
+
+// Object.
+
+clear();
+({
+  a: ( log("lhs before obj a"), obj ).a
+} = logger({a: "A"}));
+assertEq(logs.join(","),
+         [
+           "lhs before obj a",
+           "rhs get a",
+           "lhs set a",
+         ].join(","));
+assertEq(storage.values.a, "A");
+
+clear();
+({
+  a: ( log("lhs before obj a"), obj )[ (log("lhs before name a"), "a") ]
+} = logger({a: "A"}));
+assertEq(logs.join(","),
+         [
+           "lhs before obj a",
+           "lhs before name a",
+           "rhs get a",
+           "lhs set a",
+         ].join(","));
+assertEq(storage.values.a, "A");
+
+// Object combined.
+
+clear();
+({
+  a: ( log("lhs before obj a"), obj ).a,
+  b: ( log("lhs before obj b"), obj )[ (log("lhs before name b"), "b") ]
+} = logger({a: "A", b: "B"}));
+assertEq(logs.join(","),
+         [
+           "lhs before obj a",
+           "rhs get a",
+           "lhs set a",
+
+           "lhs before obj b",
+           "lhs before name b",
+           "rhs get b",
+           "lhs set b",
+         ].join(","));
+assertEq(storage.values.a, "A");
+assertEq(storage.values.b, "B");
+
+// == Nested ==
+
+// Array -> Array
+
+clear();
+[
+  [
+    ( log("lhs before obj a"), obj )[ (log("lhs before name a"), "a") ],
+    ...( log("lhs before obj b"), obj )[ (log("lhs before name b"), "b") ]
+  ]
+] = logger([["A", "B"]]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next()::value::@@iterator",
+           "rhs call @@iterator()::next()::value::@@iterator",
+
+           "lhs before obj a",
+           "lhs before name a",
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+           "lhs set a",
+
+           "lhs before obj b",
+           "lhs before name b",
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "lhs set b",
+         ].join(","));
+assertEq(storage.values.a, "A");
+assertEq(storage.values.b.length, 1);
+assertEq(storage.values.b[0], "B");
+
+// Array rest -> Array
+
+clear();
+[
+  ...[
+    ( log("lhs before obj a"), obj )[ (log("lhs before name a"), "a") ],
+    ...( log("lhs before obj b"), obj )[ (log("lhs before name b"), "b") ]
+  ]
+] = logger(["A", "B"]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+
+           "lhs before obj a",
+           "lhs before name a",
+           "lhs set a",
+
+           "lhs before obj b",
+           "lhs before name b",
+           "lhs set b",
+         ].join(","));
+assertEq(storage.values.a, "A");
+assertEq(storage.values.b.join(","), "B");
+
+// Array -> Object
+clear();
+[
+  {
+    a: ( log("lhs before obj a"), obj )[ (log("lhs before name a"), "a") ]
+  }
+] = logger([{a: "A"}]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+
+           "lhs before obj a",
+           "lhs before name a",
+           "rhs get @@iterator()::next()::value::a",
+           "lhs set a",
+         ].join(","));
+assertEq(storage.values.a, "A");
+
+// Array rest -> Object
+clear();
+[
+  ...{
+    0: ( log("lhs before obj 0"), obj )[ (log("lhs before name 0"), "0") ],
+    1: ( log("lhs before obj 1"), obj )[ (log("lhs before name 1"), "1") ],
+    length: ( log("lhs before obj length"), obj )[ (log("lhs before name length"), "length") ],
+  }
+] = logger(["A", "B"]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+
+           "lhs before obj 0",
+           "lhs before name 0",
+           "lhs set 0",
+
+           "lhs before obj 1",
+           "lhs before name 1",
+           "lhs set 1",
+
+           "lhs before obj length",
+           "lhs before name length",
+           "lhs set length",
+         ].join(","));
+assertEq(storage.values["0"], "A");
+assertEq(storage.values["1"], "B");
+assertEq(storage.values.length, 2);
+
+// Object -> Array
+clear();
+({
+  a: [
+    ( log("lhs before obj b"), obj )[ (log("lhs before name b"), "b") ]
+  ]
+} = logger({a: ["B"]}));
+assertEq(logs.join(","),
+         [
+           "rhs get a",
+           "rhs get a::@@iterator",
+           "rhs call a::@@iterator",
+
+           "lhs before obj b",
+           "lhs before name b",
+           "rhs get a::@@iterator()::next",
+           "rhs call a::@@iterator()::next",
+           "rhs get a::@@iterator()::next()::done",
+           "rhs get a::@@iterator()::next()::value",
+           "lhs set b",
+         ].join(","));
+assertEq(storage.values.b, "B");
+
+// Object -> Object
+clear();
+({
+  a: {
+    b: ( log("lhs before obj b"), obj )[ (log("lhs before name b"), "b") ]
+  }
+} = logger({a: {b: "B"}}));
+assertEq(logs.join(","),
+         [
+           "rhs get a",
+           "lhs before obj b",
+           "lhs before name b",
+           "rhs get a::b",
+           "lhs set b",
+         ].join(","));
+assertEq(storage.values.b, "B");
+
+// All combined
+
+clear();
+[
+  ( log("lhs before obj a"), obj )[ (log("lhs before name a"), "a") ],
+  [
+    ( log("lhs before obj b"), obj )[ (log("lhs before name b"), "b") ],
+    {
+      c: ( log("lhs before obj c"), obj )[ (log("lhs before name c"), "c") ],
+      d: {
+        e: ( log("lhs before obj e"), obj )[ (log("lhs before name e"), "e") ],
+        f: [
+          ( log("lhs before obj g"), obj )[ (log("lhs before name g"), "g") ]
+        ]
+      }
+    }
+  ],
+  {
+    h: ( log("lhs before obj h"), obj )[ (log("lhs before name h"), "h") ],
+    i: [
+      ( log("lhs before obj j"), obj )[ (log("lhs before name j"), "j") ],
+      {
+        k: [
+          ( log("lhs before obj l"), obj )[ (log("lhs before name l"), "l") ]
+        ]
+      }
+    ]
+  },
+  ...[
+    ( log("lhs before obj m"), obj )[ (log("lhs before name m"), "m") ],
+    [
+      ( log("lhs before obj n"), obj )[ (log("lhs before name n"), "n") ],
+      {
+        o: ( log("lhs before obj o"), obj )[ (log("lhs before name o"), "o") ],
+        p: {
+          q: ( log("lhs before obj q"), obj )[ (log("lhs before name q"), "q") ],
+          r: [
+            ( log("lhs before obj s"), obj )[ (log("lhs before name s"), "s") ]
+          ]
+        }
+      }
+    ],
+    ...{
+      0: ( log("lhs before obj t"), obj )[ (log("lhs before name t"), "t") ],
+      1: [
+        ( log("lhs before obj u"), obj )[ (log("lhs before name u"), "u") ],
+        {
+          v: ( log("lhs before obj v"), obj )[ (log("lhs before name v"), "v") ],
+          w: {
+            x: ( log("lhs before obj x"), obj )[ (log("lhs before name x"), "x") ],
+            y: [
+              ( log("lhs before obj z"), obj )[ (log("lhs before name z"), "z") ]
+            ]
+          }
+        }
+      ],
+      length: ( log("lhs before obj length"), obj )[ (log("lhs before name length"), "length") ],
+    }
+  ]
+] = logger(["A",
+            ["B", {c: "C", d: {e: "E", f: ["G"]}}],
+            {h: "H", i: ["J", {k: ["L"]}]},
+            "M",
+            ["N", {o: "O", p: {q: "Q", r: ["S"]}}],
+            "T", ["U", {v: "V", w: {x: "X", y: ["Z"]}}]]);
+assertEq(logs.join(","),
+         [
+           "rhs get @@iterator",
+           "rhs call @@iterator",
+
+           "lhs before obj a",
+           "lhs before name a",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "lhs set a",
+
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next()::value::@@iterator",
+           "rhs call @@iterator()::next()::value::@@iterator",
+
+           "lhs before obj b",
+           "lhs before name b",
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+           "lhs set b",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+
+           "lhs before obj c",
+           "lhs before name c",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::c",
+           "lhs set c",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d",
+
+           "lhs before obj e",
+           "lhs before name e",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::e",
+           "lhs set e",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator",
+           "rhs call @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator",
+
+           "lhs before obj g",
+           "lhs before name g",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::d::f::@@iterator()::next()::value",
+           "lhs set g",
+
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+
+           "lhs before obj h",
+           "lhs before name h",
+           "rhs get @@iterator()::next()::value::h",
+           "lhs set h",
+
+           "rhs get @@iterator()::next()::value::i",
+           "rhs get @@iterator()::next()::value::i::@@iterator",
+           "rhs call @@iterator()::next()::value::i::@@iterator",
+
+           "lhs before obj j",
+           "lhs before name j",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::i::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value",
+           "lhs set j",
+
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::i::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value",
+
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator",
+           "rhs call @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator",
+
+           "lhs before obj l",
+           "lhs before name l",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::i::@@iterator()::next()::value::k::@@iterator()::next()::value",
+           "lhs set l",
+
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value",
+           "rhs get @@iterator()::next",
+           "rhs call @@iterator()::next",
+           "rhs get @@iterator()::next()::done",
+
+           "lhs before obj m",
+           "lhs before name m",
+           "lhs set m",
+
+           "rhs get @@iterator()::next()::value::@@iterator",
+           "rhs call @@iterator()::next()::value::@@iterator",
+
+           "lhs before obj n",
+           "lhs before name n",
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+           "lhs set n",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+
+           "lhs before obj o",
+           "lhs before name o",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::o",
+           "lhs set o",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p",
+
+           "lhs before obj q",
+           "lhs before name q",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::q",
+           "lhs set q",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator",
+           "rhs call @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator",
+
+           "lhs before obj s",
+           "lhs before name s",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::p::r::@@iterator()::next()::value",
+           "lhs set s",
+
+           "lhs before obj t",
+           "lhs before name t",
+           "lhs set t",
+
+           "rhs get @@iterator()::next()::value::@@iterator",
+           "rhs call @@iterator()::next()::value::@@iterator",
+
+           "lhs before obj u",
+           "lhs before name u",
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+           "lhs set u",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value",
+
+           "lhs before obj v",
+           "lhs before name v",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::v",
+           "lhs set v",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w",
+
+           "lhs before obj x",
+           "lhs before name x",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::x",
+           "lhs set x",
+
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator",
+           "rhs call @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator",
+
+           "lhs before obj z",
+           "lhs before name z",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next",
+           "rhs call @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next()::done",
+           "rhs get @@iterator()::next()::value::@@iterator()::next()::value::w::y::@@iterator()::next()::value",
+           "lhs set z",
+
+           "lhs before obj length",
+           "lhs before name length",
+           "lhs set length",
+         ].join(","));
+assertEq(storage.values.a, "A");
+assertEq(storage.values.b, "B");
+assertEq(storage.values.c, "C");
+assertEq(storage.values.e, "E");
+assertEq(storage.values.g, "G");
+assertEq(storage.values.h, "H");
+assertEq(storage.values.j, "J");
+assertEq(storage.values.l, "L");
+assertEq(storage.values.m, "M");
+assertEq(storage.values.n, "N");
+assertEq(storage.values.o, "O");
+assertEq(storage.values.q, "Q");
+assertEq(storage.values.s, "S");
+assertEq(storage.values.t, "T");
+assertEq(storage.values.u, "U");
+assertEq(storage.values.v, "V");
+assertEq(storage.values.x, "X");
+assertEq(storage.values.z, "Z");
+assertEq(storage.values.length, 2);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);