Fix #775: update HTMLAllCollection to match reality better

As discussed extensively in that issue, in most browsers
HTMLAllCollection is more lenient than previously believed, especially
with regard to its item() method and legacycaller behavior.

Author: domenic

source

@@ -7142,11 +7142,9 @@ a.setAttribute('href', 'http://example.com/'); // change the content attribute d
 
   <p>The <code>HTMLAllCollection</code> interface is used for the legacy <code
   data-x="dom-document-all">document.all</code> attribute. It operates similarly to
-  <code>HTMLCollection</code>; the main differences are that its <code
-  data-x="dom-HTMLAllCollection-namedItem">namedItem()</code> method returns an
-  <code>HTMLCollection</code> object when there are multiple matching elements, and that its <code
-  data-x="dom-HTMLAllCollection-item">item()</code> method can be used as a synonym for its <code
-  data-x="dom-HTMLAllCollection-namedItem">namedItem()</code> method.</p>
+  <code>HTMLCollection</code>; the main differences are that it allows a staggering variety of
+  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 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
@@ -7156,9 +7154,9 @@ a.setAttribute('href', 'http://example.com/'); // change the content attribute d
   <pre class="idl">[LegacyUnenumerableNamedProperties]
 interface <dfn>HTMLAllCollection</dfn> {
   readonly attribute unsigned long <span data-x="dom-HTMLAllCollection-length">length</span>;
-  getter <span>Element</span>? <span data-x="dom-HTMLAllCollection-item">item</span>(unsigned long index);
-  (<span>HTMLCollection</span> or <span>Element</span>)? <span data-x="dom-HTMLAllCollection-item-string">item</span>(DOMString name);
-  legacycaller getter (<span>HTMLCollection</span> or <span>Element</span>)? <span data-x="dom-HTMLAllCollection-namedItem">namedItem</span>(DOMString name);
+  getter <span>Element</span>? (unsigned long index);
+  getter (<span>HTMLCollection</span> or <span>Element</span>)? <span data-x="dom-HTMLAllCollection-namedItem">namedItem</span>(DOMString name);
+  legacycaller (<span>HTMLCollection</span> or <span>Element</span>)? <span data-x="dom-HTMLAllCollection-item">item</span>(optional DOMString nameOrIndex);
 };</pre>
 
   <dl class="domintro">
@@ -7169,13 +7167,14 @@ interface <dfn>HTMLAllCollection</dfn> {
    </dd>
 
    <dt><var>element</var> = <var>collection</var> . <code subdfn data-x="dom-HTMLAllCollection-item">item</code>(<var>index</var>)</dt>
+   <dt><var>element</var> = <var>collection</var>(<var>index</var>)</dt>
    <dt><var>element</var> = <var>collection</var>[<var>index</var>]</dt>
    <dd>
-    <p>Returns the item with index <var>index</var> from the collection. The items are sorted in <span>tree order</span>.</p>
+    <p>Returns the item with index <var>index</var> from the collection (determined by <span>tree order</span>).</p>
    </dd>
 
-   <dt><var>element</var> = <var>collection</var> . <code subdfn data-x="dom-HTMLAllCollection-item-string">item</code>(<var>name</var>)</dt>
-   <dt><var>collection</var> = <var>collection</var> . <code data-x="dom-HTMLAllCollection-item-string">item</code>(<var>name</var>)</dt>
+   <dt><var>element</var> = <var>collection</var> . <code data-x="dom-HTMLAllCollection-item">item</code>(<var>name</var>)</dt>
+   <dt><var>collection</var> = <var>collection</var> . <code data-x="dom-HTMLAllCollection-item">item</code>(<var>name</var>)</dt>
    <dt><var>element</var> = <var>collection</var> . <code subdfn data-x="dom-HTMLAllCollection-namedItem">namedItem</code>(<var>name</var>)</dt>
    <dt><var>collection</var> = <var>collection</var> . <code data-x="dom-HTMLAllCollection-namedItem">namedItem</code>(<var>name</var>)</dt>
    <dt><var>element</var> = <var>collection</var>(<var>name</var>)</dt>
@@ -7199,6 +7198,43 @@ interface <dfn>HTMLAllCollection</dfn> {
   <p>The object's <span>supported property indices</span> are as defined for
   <code>HTMLCollection</code> objects.</p>
 
+  <p>The <span>supported property names</span> consist of the non-empty values of all the <code
+  data-x="attr-id">id</code> attributes of all the elements <span>represented by the
+  collection</span>, and the non-empty values of all the <code data-x="">name</code> attributes of
+  all the <span>"all"-named elements</span> <span>represented by the collection</span>, in
+  <span>tree order</span>, ignoring later duplicates, with the <code data-x="attr-id">id</code> of
+  an element preceding its <code data-x="">name</code> if it contributes both, they differ from each
+  other, and neither is the duplicate of an earlier entry.</p>
+
+  <p>On getting, the <dfn><code data-x="dom-HTMLAllCollection-length">length</code></dfn>
+  attribute must return the number of nodes <span>represented by the collection</span>.</p>
+
+  <p>The indexed property getter must return the result of <span
+  data-x="concept-get-all-indexed">getting the "all"-indexed element</span> from this
+  <code>HTMLAllCollection</code> given the passed index.</p>
+
+  <p>The <dfn><code data-x="dom-HTMLAllCollection-namedItem">namedItem(<var>name</var>)</code></dfn>
+  method must return the result of <span data-x="concept-get-all-named">getting the "all"-named
+  element(s)</span> from this <code>HTMLAllCollection</code> given <var>name</var>.</p>
+
+  <p>The <dfn><code data-x="dom-HTMLAllCollection-item">item(<var>nameOrIndex</var>)</code></dfn>
+  method (and the <code data-x="">legacycaller</code> behavior) must run the following steps:</p>
+
+  <ol>
+   <li><p>If <var>nameOrIndex</var> was not provided, return null.</p></li>
+
+   <li><p>If <var>nameOrIndex</var>, <span data-x="concept-idl-convert">converted</span> to a
+   JavaScript string value, is an <span>array index property name</span>, return the result of <span
+   data-x="concept-get-all-indexed">getting the "all"-indexed element</span> from this
+   <code>HTMLAllCollection</code> given the number represented by <var>nameOrIndex</var>.</p></li>
+
+   <li><p>Return the result of <span data-x="concept-get-all-named">getting the "all"-named
+   element(s)</span> from this <code>HTMLAllCollection</code> given
+   <var>nameOrIndex</var>.</p></li>
+  </ol>
+
+  <hr>
+
   <!-- http://software.hixie.ch/utilities/js/live-dom-viewer/?saved=2837 -->
   <p>The following elements are <dfn>"all"-named elements</dfn>:
    <code>a</code>, <!-- in some browsers -->
@@ -7219,53 +7255,37 @@ interface <dfn>HTMLAllCollection</dfn> {
    <code>textarea</code> <!-- in some browsers -->
   </p>
 
-  <p>The <span>supported property names</span> consist of the non-empty values of all the <code
-  data-x="attr-id">id</code> attributes of all the elements <span>represented by the
-  collection</span>, and the non-empty values of all the <code data-x="">name</code> attributes of
-  all the <span>"all"-named elements</span> <span>represented by the collection</span>, in
-  <span>tree order</span>, ignoring later duplicates, with the <code data-x="attr-id">id</code> of
-  an element preceding its <code data-x="">name</code> if it contributes both, they differ from each
-  other, and neither is the duplicate of an earlier entry.</p>
-
-  <p>On getting, the <dfn><code data-x="dom-HTMLAllCollection-length">length</code></dfn>
-  attribute must return the number of nodes <span>represented by the collection</span>.</p>
+  <p>To <dfn data-x="concept-get-all-indexed">get the "all"-indexed element</dfn> from an
+  <code>HTMLAllCollection</code> <var>collection</var> given an index <var>index</var>, return the
+  <var>index</var><sup>th</sup> element in <var>collection</var>, or null if there is no such
+  <var>index</var><sup>th</sup> element.</p>
 
-  <p>The <dfn><code data-x="dom-HTMLAllCollection-item">item(<var>index</var>)</code></dfn> method
-  must return the <var>index</var><sup>th</sup> element in the collection. If there is no
-  <var>index</var><sup>th</sup> element in the <span data-x="concept-collection">collection</span>,
-  then the method must return null.</p>
-
-  <p>The <dfn><code data-x="dom-HTMLAllCollection-item-string">item(<var>name</var>)</code></dfn> and <dfn><code data-x="dom-HTMLAllCollection-namedItem">namedItem(<var>name</var>)</code></dfn>
-  methods must act according to the following algorithm:</p>
+  <p>To <dfn data-x="concept-get-all-named">get the "all"-named element(s)</dfn> from an
+  <code>HTMLAllCollection</code> <var>collection</var> given a name <var>name</var>, perform the
+  following steps:</p>
 
   <ol>
-
-   <li>If <var>name</var> is the empty string, return null and stop the algorithm.</li>
+   <li><p>If <var>name</var> is the empty string, return null.</p></li>
 
    <li>
-
-    <p>Let <var>collection</var> be an <code>HTMLCollection</code> object rooted at the
-    same <code>Document</code> as the <code>HTMLAllCollection</code> object on which the method was
-    invoked, whose filter matches only elements that are either:</p>
+    <p>Let <var>subCollection</var> be an <code>HTMLCollection</code> object rooted at the same
+    <code>Document</code> as <var>collection</var>, whose filter matches only elements that are
+    either:</p>
 
     <ul>
+     <li><p><span>"all"-named elements</span> with a <code data-x="">name</code> attribute equal to
+     <var>name</var>, or,</p></li>
 
-     <li><span>"all"-named elements</span> with a <code data-x="">name</code> attribute equal to
-     <var>name</var>, or,</li>
-
-     <li>elements with an <span data-x="concept-id">ID</span> equal to <var>name</var>.</li>
-
+     <li><p>elements with an <span data-x="concept-id">ID</span> equal to <var>name</var>.</p></li>
     </ul>
-
    </li>
 
-   <li>If, at the time the method is called, there is exactly one node in <var>collection</var>, then return that node and stop the algorithm.</li>
-
-   <li>Otherwise, if, at the time the method is called, <var>collection</var> is empty,
-   return null and stop the algorithm.</li>
+   <li><p>If there is exactly one element in <var>subCollection</var>, then return that
+   element.</p></li>
 
-   <li>Otherwise, return <var>collection</var>.</li>
+   <li><p>Otherwise, if <var>subCollection</var> is empty, return null.</p></li>
 
+   <li><p>Otherwise, return <var>subCollection</var>.</p></li>
   </ol>
 
   </div>
@@ -117160,6 +117180,7 @@ INSERT INTERFACES HERE
   Anthony Boyd,
   Anthony Bryan,
   Anthony Hickson,
+  Anthony Ramine,
   Anthony Ricaud,
   Antti Koivisto,
   Arkadiusz Michalski,