Define document.all as having [[IsHTMLDDA]]

Fixes #3015.

Author: TimothyGu

source

@@ -3055,6 +3055,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li>The <dfn data-x-href="https://tc39.github.io/ecma262/#sec-sharedarraybuffer-objects"><code>SharedArrayBuffer</code></dfn> class</li>
      <li>The <dfn data-x-href="https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror"><code>TypeError</code></dfn> class</li>
      <li>The <dfn data-x="js-RangeError" data-x-href="https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-rangeerror"><code>RangeError</code></dfn> class</li>
+     <li>The <dfn data-x-href="https://tc39.github.io/ecma262/#sec-IsHTMLDDA-internal-slot">[[IsHTMLDDA]]</dfn> internal slot</li>
      <li>The <dfn data-x="js-typeof" data-x-href="https://tc39.github.io/ecma262/#sec-typeof-operator"><code>typeof</code></dfn> operator</li>
      <li><dfn data-x-href="https://tc39.github.io/ecma262/#table-49">The <var>TypedArray</var> Constructors</dfn> table</li>
     </ul>
@@ -7157,15 +7158,43 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
   different (ab)uses of its methods to all end up returning something, and that it can be called as
   a function as an alternative to property access.</p>
 
-  <p w-nodev>Objects that implement the <code>HTMLAllCollection</code> interface are <span
-  data-x="legacy platform object">legacy platform objects</span> with an additonal [[Call]] internal
-  method described in the <a href="#HTMLAllCollection-call">section below</a>.</p>
-
   <p class="note">All <code>HTMLAllCollection</code> objects are rooted at a <code>Document</code>
   and have a filter that matches all elements, so the elements <span>represented by the
   collection</span> of an <code>HTMLAllCollection</code> object consist of all the descendant
   elements of the root <code>Document</code>.</p>
 
+  <p w-nodev>Objects that implement the <code>HTMLAllCollection</code> interface are <span
+  data-x="legacy platform object">legacy platform objects</span> with an additonal [[Call]] internal
+  method described in the <a href="#HTMLAllCollection-call">section below</a>. They also have an
+  <span>[[IsHTMLDDA]]</span> internal slot.</p>
+
+  <div class="note">
+   <p>Objects that implement the <code>HTMLAllCollection</code> interface have several unusual
+   behaviors, due of the fact that they have an <span>[[IsHTMLDDA]]</span> internal slot:</p>
+
+   <ul>
+    <li><p>The <span data-x="js-ToBoolean">ToBoolean</span> abstract operation in JavaScript returns
+    false when given objects implementing the <code>HTMLAllCollection</code> interface.</p></li>
+
+    <li><p>The <span data-x="js-abstract-equality">Abstract Equality Comparison</span> algorithm,
+    when given objects implementing the <code>HTMLAllCollection</code> interface, returns true when
+    compared to the <code data-x="">undefined</code> and <code data-x="">null</code> values.
+    (Comparisons using the <span data-x="js-strict-equality">Strict Equality Comparison</span>
+    algorithm, and Abstract Equality comparisons to other values such as strings or objects, are
+    unaffected.)</p></li>
+
+    <li><p>The <code data-x="js-typeof">typeof</code> operator in JavaScript returns the string
+    <code data-x="">"undefined"</code> when applied to objects implementing the
+    <code>HTMLAllCollection</code> interface.</p></li>
+   </ul>
+
+   <p>These special behaviors are motivated by a desire for compatibility with two classes of legacy
+   content: one that uses the presence of <code data-x="dom-document-all">document.all</code> as a
+   way to detect legacy user agents, and one that only supports those legacy user agents and uses
+   the <code data-x="dom-document-all">document.all</code> object without testing for its presence
+   first. <ref spec=JAVASCRIPT></p>
+  </div>
+
   <pre class="idl">[Exposed=Window,
  LegacyUnenumerableNamedProperties]
 interface <dfn>HTMLAllCollection</dfn> {
@@ -7174,7 +7203,7 @@ interface <dfn>HTMLAllCollection</dfn> {
   getter (<span>HTMLCollection</span> or <span>Element</span>)? <span data-x="dom-HTMLAllCollection-namedItem">namedItem</span>(DOMString name);
   (<span>HTMLCollection</span> or <span>Element</span>)? <span data-x="dom-HTMLAllCollection-item">item</span>(optional DOMString nameOrIndex);
 
-  // Note: HTMLAllCollection objects have a <a href="#HTMLAllCollection-call">custom [[Call]] internal method</a>.
+  // Note: HTMLAllCollection objects have a <a href="#HTMLAllCollection-call">custom [[Call]] internal method</a> and an <span>[[IsHTMLDDA]]</span> internal slot.
 };</pre>
 
   <dl class="domintro">
@@ -114105,38 +114134,6 @@ interface <dfn>HTMLFontElement</dfn> : <span>HTMLElement</span> {
   <code>HTMLAllCollection</code> rooted at the <code>Document</code> node, whose filter matches all
   elements.</p>
 
-  <p>The object returned for <code data-x="dom-document-all">all</code> has several unusual
-  behaviors:</p>
-
-  <ul>
-
-   <li><p>The user agent must act as if the <span data-x="js-ToBoolean">ToBoolean</span> abstract
-   operation in JavaScript returns false when given the object returned for <code
-   data-x="dom-document-all">all</code>.</p></li>
-
-   <li><p>The user agent must act as if the <span data-x="js-abstract-equality">Abstract Equality
-   Comparison</span> algorithm, when given the object returned for <code
-   data-x="dom-document-all">all</code>, returns true when compared to the <code
-   data-x="">undefined</code> and <code data-x="">null</code> values. (Comparisons using the <span
-   data-x="js-strict-equality">Strict Equality Comparison</span> algorithm, and Abstract Equality
-   comparisons to other values such as strings or objects, are unaffected.)</p></li>
-
-   <li><p>The user agent must act such that the <code data-x="js-typeof">typeof</code> operator in
-   JavaScript returns the string <code data-x="">"undefined"</code> when applied to the object
-   returned for <code data-x="dom-document-all">all</code>.</p></li>
-
-  </ul>
-
-  <p class="note">These requirements are a <span>willful violation</span> of the JavaScript
-  specification current at the time of writing. The JavaScript specification
-  requires that <span data-x="js-ToBoolean">ToBoolean</span> return true for all objects, and does not have
-  provisions for objects acting as if they were <code data-x="">undefined</code> for the purposes of
-  certain operators. This violation is motivated by a desire for compatibility with two classes of
-  legacy content: one that uses the presence of <code data-x="dom-document-all">document.all</code>
-  as a way to detect legacy user agents, and one that only supports those legacy user agents and
-  uses the <code data-x="dom-document-all">document.all</code> object without testing for its
-  presence first. <ref spec=JAVASCRIPT></p>
-
   <hr>
 
   <pre class="idl">partial interface <span id="Window-partial">Window</span> {