cyclic.patch

## cyclic.patch
diff --git a/spec.html b/spec.html
index ec3918c..e8f809c 100644
--- a/spec.html
+++ b/spec.html
@@ -5796,6 +5796,17 @@
             Template objects are canonicalized separately for each realm using its Realm Record's [[templateMap]]. Each [[strings]] value is a List containing, in source text order, the raw String values of a |TemplateLiteral| that has been evaluated. The associated [[array]] value is the corresponding template object that is passed to a tag function.
           </td>
         </tr>
+        <tr>
+          <td>
+            [[arrayJoinCyclicSet]]
+          </td>
+          <td>
+            A List of objects.
+          </td>
+          <td>
+            (Objects in Array.prototype.join and friends.)
+          </td>
+        </tr>
         </tbody>
       </table>
     </emu-table>
@@ -29836,24 +29847,39 @@ Date.parse(x.toLocaleString())
         <p>The `join` method takes one argument, _separator_, and performs the following steps:</p>
         <emu-alg>
           1. Let _O_ be ? ToObject(*this* value).
-          1. Let _len_ be ? ToLength(? Get(_O_, `"length"`)).
-          1. If _separator_ is *undefined*, let _separator_ be the single-element String `","`.
-          1. Let _sep_ be ? ToString(_separator_).
-          1. If _len_ is zero, return the empty String.
-          1. Let _element0_ be Get(_O_, `"0"`).
-          1. If _element0_ is *undefined* or *null*, let _R_ be the empty String; otherwise, let _R_ be ? ToString(_element0_).
-          1. Let _k_ be `1`.
-          1. Repeat, while _k_ &lt; _len_
-            1. Let _S_ be the String value produced by concatenating _R_ and _sep_.
-            1. Let _element_ be ? Get(_O_, ! ToString(_k_)).
-            1. If _element_ is *undefined* or *null*, let _next_ be the empty String; otherwise, let _next_ be ? ToString(_element_).
-            1. Let _R_ be a String value produced by concatenating _S_ and _next_.
-            1. Increase _k_ by 1.
-          1. Return _R_.
+          1. Let _realm_ be the current Realm Record.
+          1. Let _set_ be _realm_.[[arrayJoinCyclicSet]].
+          1. If _set_ contains _O_, return `""`.
+          1. Append _O_ as the last element of _set_.
+          1. Let _result_ be ArrayJoin(_O_, _separator_).
+          1. Remove the last element of _set_.
+          1. Return _result_.
         </emu-alg>
         <emu-note>
           <p>The `join` function is intentionally generic; it does not require that its *this* value be an Array object. Therefore, it can be transferred to other kinds of objects for use as a method.</p>
         </emu-note>
+
+        <emu-clause id="sec-array-join" aoid="ArrayJoin">
+          <h1>Runtime Semantics: ArrayJoin ( _O_ )</h1>
+          <p>The abstract operation ArrayJoin with arguments _O_ and _separator_ performs the following steps:</p>
+          <emu-alg>
+            1. Assert: Type(_O_) is Object.
+            1. Let _len_ be ? ToLength(? Get(_O_, `"length"`)).
+            1. If _separator_ is *undefined*, let _separator_ be the single-element String `","`.
+            1. Let _sep_ be ? ToString(_separator_).
+            1. If _len_ is zero, return the empty String.
+            1. Let _element0_ be Get(_O_, `"0"`).
+            1. If _element0_ is *undefined* or *null*, let _R_ be the empty String; otherwise, let _R_ be ? ToString(_element0_).
+            1. Let _k_ be `1`.
+            1. Repeat, while _k_ &lt; _len_
+              1. Let _S_ be the String value produced by concatenating _R_ and _sep_.
+              1. Let _element_ be ? Get(_O_, ! ToString(_k_)).
+              1. If _element_ is *undefined* or *null*, let _next_ be the empty String; otherwise, let _next_ be ? ToString(_element_).
+              1. Let _R_ be a String value produced by concatenating _S_ and _next_.
+              1. Increase _k_ by 1.
+            1. Return _R_.
+          </emu-alg>
+        </emu-clause>
       </emu-clause>

       <!-- es6num="22.1.3.13" -->
@@ -30428,25 +30454,13 @@ Date.parse(x.toLocaleString())
         <p>The following steps are taken:</p>
         <emu-alg>
           1. Let _array_ be ? ToObject(*this* value).
-          1. Let _len_ be ? ToLength(? Get(_array_, `"length"`)).
-          1. Let _separator_ be the String value for the list-separator String appropriate for the host environment's current locale (this is derived in an implementation-defined way).
-          1. If _len_ is zero, return the empty String.
-          1. Let _firstElement_ be ? Get(_array_, `"0"`).
-          1. If _firstElement_ is *undefined* or *null*, then
-            1. Let _R_ be the empty String.
-          1. Else,
-            1. Let _R_ be ? ToString(? Invoke(_firstElement_, `"toLocaleString"`)).
-          1. Let _k_ be `1`.
-          1. Repeat, while _k_ &lt; _len_
-            1. Let _S_ be a String value produced by concatenating _R_ and _separator_.
-            1. Let _nextElement_ be ? Get(_array_, ! ToString(_k_)).
-            1. If _nextElement_ is *undefined* or *null*, then
-              1. Let _R_ be the empty String.
-            1. Else,
-              1. Let _R_ be ? ToString(? Invoke(_nextElement_, `"toLocaleString"`)).
-            1. Let _R_ be a String value produced by concatenating _S_ and _R_.
-            1. Increase _k_ by 1.
-          1. Return _R_.
+          1. Let _realm_ be the current Realm Record.
+          1. Let _set_ be _realm_.[[arrayJoinCyclicSet]].
+          1. If _set_ contains _array_, return `""`.
+          1. Append _array_ as the last element of _set_.
+          1. Let _result_ be ArrayToLocaleString(_array_).
+          1. Remove the last element of _set_.
+          1. Return _result_.
         </emu-alg>
         <emu-note>
           <p>The elements of the array are converted to Strings using their `toLocaleString` methods, and these Strings are then concatenated, separated by occurrences of a separator String that has been derived in an implementation-defined locale-specific way. The result of calling this function is intended to be analogous to the result of `toString`, except that the result of this function is intended to be locale-specific.</p>
@@ -30454,6 +30468,33 @@ Date.parse(x.toLocaleString())
         <emu-note>
           <p>The `toLocaleString` function is intentionally generic; it does not require that its *this* value be an Array object. Therefore it can be transferred to other kinds of objects for use as a method.</p>
         </emu-note>
+
+        <emu-clause id="sec-array-tolocalestring" aoid="ArrayToLocaleString">
+          <h1>Runtime Semantics: ArrayToLocaleString ( _array_ )</h1>
+          <p>The abstract operation ArrayToLocaleString with argument _array_ performs the following steps:</p>
+          <emu-alg>
+            1. Assert: Type(_array_) is Object.
+            1. Let _len_ be ? ToLength(? Get(_array_, `"length"`)).
+            1. Let _separator_ be the String value for the list-separator String appropriate for the host environment's current locale (this is derived in an implementation-defined way).
+            1. If _len_ is zero, return the empty String.
+            1. Let _firstElement_ be ? Get(_array_, `"0"`).
+            1. If _firstElement_ is *undefined* or *null*, then
+              1. Let _R_ be the empty String.
+            1. Else,
+              1. Let _R_ be ? ToString(? Invoke(_firstElement_, `"toLocaleString"`)).
+            1. Let _k_ be `1`.
+            1. Repeat, while _k_ &lt; _len_
+              1. Let _S_ be a String value produced by concatenating _R_ and _separator_.
+              1. Let _nextElement_ be ? Get(_array_, ! ToString(_k_)).
+              1. If _nextElement_ is *undefined* or *null*, then
+                1. Let _R_ be the empty String.
+              1. Else,
+                1. Let _R_ be ? ToString(? Invoke(_nextElement_, `"toLocaleString"`)).
+              1. Let _R_ be a String value produced by concatenating _S_ and _R_.
+              1. Increase _k_ by 1.
+            1. Return _R_.
+          </emu-alg>
+        </emu-clause>
       </emu-clause>

       <!-- es6num="22.1.3.27" -->