diff --git a/src/dstr-binding/ary-ptrn-rest-obj-prop-id.case b/src/dstr-binding/ary-ptrn-rest-obj-prop-id.case
index 2f6ace55dc..3ad1150230 100644
--- a/src/dstr-binding/ary-ptrn-rest-obj-prop-id.case
+++ b/src/dstr-binding/ary-ptrn-rest-obj-prop-id.case
@@ -18,6 +18,8 @@ info: |
        [...]
 ---*/
 
+//- setup
+let length = "outer";
 //- elems
 [...{ 0: v, 1: w, 2: x, 3: y, length: z }]
 //- vals
@@ -29,6 +31,4 @@ assert.sameValue(x, 9);
 assert.sameValue(y, undefined);
 assert.sameValue(z, 3);
 
-assert.throws(ReferenceError, function() {
-  length;
-});
+assert.sameValue(length, "outer", "the length prop is not set as a binding name");
diff --git a/test/language/expressions/arrow-function/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/arrow-function/dstr-ary-ptrn-rest-obj-prop-id.js
index 6c82a5fe1a..261d98d128 100644
--- a/test/language/expressions/arrow-function/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/arrow-function/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -50,6 +50,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var f;
@@ -60,9 +61,7 @@ f = ([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) => {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/arrow-function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/arrow-function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
index 2b8a3acb7c..1ed2b981c6 100644
--- a/test/language/expressions/arrow-function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/arrow-function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -50,6 +50,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var f;
@@ -60,9 +61,7 @@ f = ([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) => {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js
index d4fd7cb2fe..27e87a49da 100644
--- a/test/language/expressions/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -29,6 +29,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -40,9 +41,7 @@ f = async function*([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
index ac09037c40..3f9a1d77ab 100644
--- a/test/language/expressions/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -29,6 +29,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -40,9 +41,7 @@ f = async function*([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/async-generator/dstr-named-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/async-generator/dstr-named-ary-ptrn-rest-obj-prop-id.js
index 5f7ed6ea3e..a5f964f4e6 100644
--- a/test/language/expressions/async-generator/dstr-named-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/async-generator/dstr-named-ary-ptrn-rest-obj-prop-id.js
@@ -29,6 +29,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -40,9 +41,7 @@ f = async function* h([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/async-generator/dstr-named-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/async-generator/dstr-named-dflt-ary-ptrn-rest-obj-prop-id.js
index 78add3a197..9c39370f67 100644
--- a/test/language/expressions/async-generator/dstr-named-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/async-generator/dstr-named-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -29,6 +29,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -40,9 +41,7 @@ f = async function* h([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
index 3163b8bc1b..e0070423a2 100644
--- a/test/language/expressions/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
@@ -53,6 +53,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -64,9 +65,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index 083dea0f7b..3044a84cd6 100644
--- a/test/language/expressions/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -53,6 +53,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -64,9 +65,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
index 3f24b5b0f3..68c6d21ba3 100644
--- a/test/language/expressions/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
@@ -53,6 +53,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -64,9 +65,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
index 32d88bded5..a95e9fd43c 100644
--- a/test/language/expressions/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -53,6 +53,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -64,9 +65,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
index df64b15a02..29f38328e7 100644
--- a/test/language/expressions/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
@@ -74,6 +74,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -84,9 +85,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index 732d662e49..06b8d0fcfe 100644
--- a/test/language/expressions/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -74,6 +74,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -84,9 +85,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
index b56adb3024..ca2b8339a4 100644
--- a/test/language/expressions/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
@@ -74,6 +74,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -84,9 +85,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
index 4d3741bc65..e3ec53e236 100644
--- a/test/language/expressions/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -74,6 +74,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -84,9 +85,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js
index f75a94a129..ace7d0eba2 100644
--- a/test/language/expressions/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js
@@ -71,6 +71,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -81,9 +82,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index de108a6515..52a0895c9c 100644
--- a/test/language/expressions/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -71,6 +71,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -81,9 +82,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js
index 9d319a248a..95282639de 100644
--- a/test/language/expressions/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js
@@ -71,6 +71,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -81,9 +82,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
index 103feca683..1fe28fffe4 100644
--- a/test/language/expressions/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -71,6 +71,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var C = class {
@@ -81,9 +82,7 @@ var C = class {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/function/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/function/dstr-ary-ptrn-rest-obj-prop-id.js
index 293166c407..6409a9cd76 100644
--- a/test/language/expressions/function/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/function/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -51,6 +51,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var f;
@@ -61,9 +62,7 @@ f = function([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
index aeedc5c860..ca8a9b9787 100644
--- a/test/language/expressions/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -51,6 +51,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var f;
@@ -61,9 +62,7 @@ f = function([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/generators/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/generators/dstr-ary-ptrn-rest-obj-prop-id.js
index 823106b4bf..07b9571534 100644
--- a/test/language/expressions/generators/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/generators/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -51,6 +51,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var f;
@@ -61,9 +62,7 @@ f = function*([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
index 0df9cd4e21..17c92e9732 100644
--- a/test/language/expressions/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -51,6 +51,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var f;
@@ -61,9 +62,7 @@ f = function*([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 
diff --git a/test/language/expressions/object/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/object/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
index e3601f3a8c..4576672139 100644
--- a/test/language/expressions/object/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/object/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
@@ -34,6 +34,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -45,9 +46,7 @@ var obj = {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/object/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/object/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index ee5540b8a0..3bd4883e99 100644
--- a/test/language/expressions/object/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/object/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -34,6 +34,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -45,9 +46,7 @@ var obj = {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/object/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/object/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
index 64b9e940ec..d7a60520cd 100644
--- a/test/language/expressions/object/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/object/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
@@ -56,6 +56,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var obj = {
@@ -66,9 +67,7 @@ var obj = {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/object/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/object/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index 29bc12f334..efbbc9e707 100644
--- a/test/language/expressions/object/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/object/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -56,6 +56,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var obj = {
@@ -66,9 +67,7 @@ var obj = {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/object/dstr-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/object/dstr-meth-ary-ptrn-rest-obj-prop-id.js
index bb18facce3..d297a40d67 100644
--- a/test/language/expressions/object/dstr-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/object/dstr-meth-ary-ptrn-rest-obj-prop-id.js
@@ -53,6 +53,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var obj = {
@@ -63,9 +64,7 @@ var obj = {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/expressions/object/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/expressions/object/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index f2853d38e7..78e351570e 100644
--- a/test/language/expressions/object/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/expressions/object/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -53,6 +53,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 var obj = {
@@ -63,9 +64,7 @@ var obj = {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js
index 01b3ef05d0..535a402bf9 100644
--- a/test/language/statements/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/async-generator/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -29,6 +29,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -39,9 +40,7 @@ async function* f([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 f([7, 8, 9]).next().then(() => {
diff --git a/test/language/statements/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
index a5ffa82fc0..a5c4ff51ee 100644
--- a/test/language/statements/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/async-generator/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -29,6 +29,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -39,9 +40,7 @@ async function* f([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 f().next().then(() => {
diff --git a/test/language/statements/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
index 4436e25d7f..7f041e6f81 100644
--- a/test/language/statements/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-async-gen-meth-ary-ptrn-rest-obj-prop-id.js
@@ -52,6 +52,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -63,9 +64,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index ab09cc6560..8206c8f266 100644
--- a/test/language/statements/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-async-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -52,6 +52,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -63,9 +64,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
index b5cfc7f23e..425dd19e28 100644
--- a/test/language/statements/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-async-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
@@ -52,6 +52,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -63,9 +64,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
index eca28ce5b2..4b2dabd2fd 100644
--- a/test/language/statements/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-async-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -52,6 +52,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 
 var callCount = 0;
@@ -63,9 +64,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
index a09c3daed3..86486817e9 100644
--- a/test/language/statements/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-gen-meth-ary-ptrn-rest-obj-prop-id.js
@@ -72,6 +72,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -82,9 +83,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index 112830090b..f860651bdc 100644
--- a/test/language/statements/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-gen-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -72,6 +72,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -82,9 +83,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
index e2c6260997..4a0c9022f0 100644
--- a/test/language/statements/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-gen-meth-static-ary-ptrn-rest-obj-prop-id.js
@@ -72,6 +72,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -82,9 +83,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
index b1fba994a2..251301d490 100644
--- a/test/language/statements/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-gen-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -72,6 +72,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -82,9 +83,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js
index 9459fd0af6..48a0999c90 100644
--- a/test/language/statements/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-meth-ary-ptrn-rest-obj-prop-id.js
@@ -70,6 +70,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -80,9 +81,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
index 447c10d94d..e2915b4058 100644
--- a/test/language/statements/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-meth-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -70,6 +70,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -80,9 +81,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js
index e8620ef950..693148c62b 100644
--- a/test/language/statements/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-meth-static-ary-ptrn-rest-obj-prop-id.js
@@ -70,6 +70,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -80,9 +81,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
index d8f0410c05..5ffbd7519c 100644
--- a/test/language/statements/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/class/dstr-meth-static-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -70,6 +70,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 class C {
@@ -80,9 +81,7 @@ class C {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
     callCount = callCount + 1;
   }
 };
diff --git a/test/language/statements/const/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/const/dstr-ary-ptrn-rest-obj-prop-id.js
index f9137c5a21..3dcb8fa202 100644
--- a/test/language/statements/const/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/const/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -30,6 +30,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 const [...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9];
 
@@ -39,6 +40,4 @@ assert.sameValue(x, 9);
 assert.sameValue(y, undefined);
 assert.sameValue(z, 3);
 
-assert.throws(ReferenceError, function() {
-  length;
-});
+assert.sameValue(length, "outer", "the length prop is not set as a binding name");
diff --git a/test/language/statements/for-await-of/async-func-dstr-const-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-await-of/async-func-dstr-const-ary-ptrn-rest-obj-prop-id.js
index 862dd2c06a..12c64f2a29 100644
--- a/test/language/statements/for-await-of/async-func-dstr-const-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-await-of/async-func-dstr-const-ary-ptrn-rest-obj-prop-id.js
@@ -48,6 +48,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ async function fn() {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
     iterCount += 1;
   }
diff --git a/test/language/statements/for-await-of/async-func-dstr-let-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-await-of/async-func-dstr-let-ary-ptrn-rest-obj-prop-id.js
index b910e4c332..5229666c3a 100644
--- a/test/language/statements/for-await-of/async-func-dstr-let-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-await-of/async-func-dstr-let-ary-ptrn-rest-obj-prop-id.js
@@ -48,6 +48,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ async function fn() {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
     iterCount += 1;
   }
diff --git a/test/language/statements/for-await-of/async-func-dstr-var-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-await-of/async-func-dstr-var-ary-ptrn-rest-obj-prop-id.js
index bc7ae32b47..a6c6450206 100644
--- a/test/language/statements/for-await-of/async-func-dstr-var-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-await-of/async-func-dstr-var-ary-ptrn-rest-obj-prop-id.js
@@ -45,6 +45,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -56,9 +57,7 @@ async function fn() {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
     iterCount += 1;
   }
diff --git a/test/language/statements/for-await-of/async-gen-dstr-const-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-await-of/async-gen-dstr-const-ary-ptrn-rest-obj-prop-id.js
index c6bf5763c8..0d9ae86141 100644
--- a/test/language/statements/for-await-of/async-gen-dstr-const-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-await-of/async-gen-dstr-const-ary-ptrn-rest-obj-prop-id.js
@@ -48,6 +48,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ async function *fn() {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
     iterCount += 1;
   }
diff --git a/test/language/statements/for-await-of/async-gen-dstr-let-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-await-of/async-gen-dstr-let-ary-ptrn-rest-obj-prop-id.js
index 9b0f1d53f6..1c45ca05d4 100644
--- a/test/language/statements/for-await-of/async-gen-dstr-let-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-await-of/async-gen-dstr-let-ary-ptrn-rest-obj-prop-id.js
@@ -48,6 +48,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ async function *fn() {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
     iterCount += 1;
   }
diff --git a/test/language/statements/for-await-of/async-gen-dstr-var-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-await-of/async-gen-dstr-var-ary-ptrn-rest-obj-prop-id.js
index c94993506e..3bf9855389 100644
--- a/test/language/statements/for-await-of/async-gen-dstr-var-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-await-of/async-gen-dstr-var-ary-ptrn-rest-obj-prop-id.js
@@ -45,6 +45,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -56,9 +57,7 @@ async function *fn() {
     assert.sameValue(y, undefined);
     assert.sameValue(z, 3);
 
-    assert.throws(ReferenceError, function() {
-      length;
-    });
+    assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
     iterCount += 1;
   }
diff --git a/test/language/statements/for-of/dstr-const-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-of/dstr-const-ary-ptrn-rest-obj-prop-id.js
index 1f8c4af381..ad34210314 100644
--- a/test/language/statements/for-of/dstr-const-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-of/dstr-const-ary-ptrn-rest-obj-prop-id.js
@@ -49,6 +49,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ for (const [...{ 0: v, 1: w, 2: x, 3: y, length: z }] of [[7, 8, 9]]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
   iterCount += 1;
 }
diff --git a/test/language/statements/for-of/dstr-let-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-of/dstr-let-ary-ptrn-rest-obj-prop-id.js
index df325a3e27..99ad5ec7e2 100644
--- a/test/language/statements/for-of/dstr-let-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-of/dstr-let-ary-ptrn-rest-obj-prop-id.js
@@ -49,6 +49,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ for (let [...{ 0: v, 1: w, 2: x, 3: y, length: z }] of [[7, 8, 9]]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
   iterCount += 1;
 }
diff --git a/test/language/statements/for-of/dstr-var-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for-of/dstr-var-ary-ptrn-rest-obj-prop-id.js
index ec51f71e1c..ce2cee0bbe 100644
--- a/test/language/statements/for-of/dstr-var-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for-of/dstr-var-ary-ptrn-rest-obj-prop-id.js
@@ -46,6 +46,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -56,9 +57,7 @@ for (var [...{ 0: v, 1: w, 2: x, 3: y, length: z }] of [[7, 8, 9]]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
   iterCount += 1;
 }
diff --git a/test/language/statements/for/dstr-const-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for/dstr-const-ary-ptrn-rest-obj-prop-id.js
index e880554ea2..27c5ac5616 100644
--- a/test/language/statements/for/dstr-const-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for/dstr-const-ary-ptrn-rest-obj-prop-id.js
@@ -49,6 +49,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ for (const [...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]; iterCount < 1
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
   iterCount += 1;
 }
diff --git a/test/language/statements/for/dstr-let-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for/dstr-let-ary-ptrn-rest-obj-prop-id.js
index ccc30499f3..eb8d6e29ed 100644
--- a/test/language/statements/for/dstr-let-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for/dstr-let-ary-ptrn-rest-obj-prop-id.js
@@ -49,6 +49,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -59,9 +60,7 @@ for (let [...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]; iterCount < 1;
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
 
   iterCount += 1;
 }
diff --git a/test/language/statements/for/dstr-var-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/for/dstr-var-ary-ptrn-rest-obj-prop-id.js
index 825201e52e..96efe5fcf5 100644
--- a/test/language/statements/for/dstr-var-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/for/dstr-var-ary-ptrn-rest-obj-prop-id.js
@@ -43,6 +43,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var iterCount = 0;
 
@@ -53,9 +54,7 @@ for (var [...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]; iterCount < 1;
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   iterCount += 1;
 }
 
diff --git a/test/language/statements/function/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/function/dstr-ary-ptrn-rest-obj-prop-id.js
index 55c13c44c8..cee830b293 100644
--- a/test/language/statements/function/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/function/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -52,6 +52,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 function f([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
@@ -61,9 +62,7 @@ function f([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 f([7, 8, 9]);
diff --git a/test/language/statements/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
index e10f62a5cb..1ec7dbaa2e 100644
--- a/test/language/statements/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/function/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -52,6 +52,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 function f([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
@@ -61,9 +62,7 @@ function f([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 f();
diff --git a/test/language/statements/generators/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/generators/dstr-ary-ptrn-rest-obj-prop-id.js
index e609bef4ed..da0edfeb49 100644
--- a/test/language/statements/generators/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/generators/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -51,6 +51,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 function* f([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
@@ -60,9 +61,7 @@ function* f([...{ 0: v, 1: w, 2: x, 3: y, length: z }]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 f([7, 8, 9]).next();
diff --git a/test/language/statements/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
index b2b54f17f5..c1528e9fb5 100644
--- a/test/language/statements/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/generators/dstr-dflt-ary-ptrn-rest-obj-prop-id.js
@@ -51,6 +51,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var callCount = 0;
 function* f([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
@@ -60,9 +61,7 @@ function* f([...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9]) {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   callCount = callCount + 1;
 };
 f().next();
diff --git a/test/language/statements/let/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/let/dstr-ary-ptrn-rest-obj-prop-id.js
index 5ea4e9ff7f..dbf4483a66 100644
--- a/test/language/statements/let/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/let/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -30,6 +30,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 let [...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9];
 
@@ -39,6 +40,4 @@ assert.sameValue(x, 9);
 assert.sameValue(y, undefined);
 assert.sameValue(z, 3);
 
-assert.throws(ReferenceError, function() {
-  length;
-});
+assert.sameValue(length, "outer", "the length prop is not set as a binding name");
diff --git a/test/language/statements/try/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/try/dstr-ary-ptrn-rest-obj-prop-id.js
index 62a6f2d5e6..b5e7cd746e 100644
--- a/test/language/statements/try/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/try/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -28,6 +28,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var ranCatch = false;
 
@@ -40,9 +41,7 @@ try {
   assert.sameValue(y, undefined);
   assert.sameValue(z, 3);
 
-  assert.throws(ReferenceError, function() {
-    length;
-  });
+  assert.sameValue(length, "outer", "the length prop is not set as a binding name");
   ranCatch = true;
 }
 
diff --git a/test/language/statements/variable/dstr-ary-ptrn-rest-obj-prop-id.js b/test/language/statements/variable/dstr-ary-ptrn-rest-obj-prop-id.js
index 8eaa6019bc..fa77487201 100644
--- a/test/language/statements/variable/dstr-ary-ptrn-rest-obj-prop-id.js
+++ b/test/language/statements/variable/dstr-ary-ptrn-rest-obj-prop-id.js
@@ -29,6 +29,7 @@ info: |
              BindingPattern with A and environment as the arguments.
        [...]
 ---*/
+let length = "outer";
 
 var [...{ 0: v, 1: w, 2: x, 3: y, length: z }] = [7, 8, 9];
 
@@ -38,6 +39,4 @@ assert.sameValue(x, 9);
 assert.sameValue(y, undefined);
 assert.sameValue(z, 3);
 
-assert.throws(ReferenceError, function() {
-  length;
-});
+assert.sameValue(length, "outer", "the length prop is not set as a binding name");