[selectors-4] Limit :nth-child() etc. to compound selectors. w3c#3760

Author: fantasai

selectors-4/Overview.bs

@@ -2834,7 +2834,7 @@ Child-indexed Pseudo-classes</h3>
 	are among <var>An+B</var>th elements
 	from the list composed of
 	their <a>inclusive siblings</a> that match the <a>selector list</a> <var>S</var>,
-	which is [=parsed as a forgiving selector list=].
+	which is a <<compound-selector-list>> [=parsed as a forgiving selector list=].
 	If <var>S</var> is omitted,
 	it defaults to ''*|*''.
 
@@ -2922,6 +2922,9 @@ Child-indexed Pseudo-classes</h3>
 		</pre>
 	</div>
 
+	Note: We intend to extend '':nth-child()'' to accept <<complex-selector-list>>
+	in Level 5.
+
 <h4 id="the-nth-last-child-pseudo">
 '':nth-last-child()'' pseudo-class</h4>
 
@@ -2931,7 +2934,7 @@ Child-indexed Pseudo-classes</h3>
 	from the list composed of
 	their <a>inclusive siblings</a> that match the <a>selector list</a> <var>S</var>,
 	counting backwards from the end.
-	<var>S</var> is [=parsed as a forgiving selector list=].
+	<var>S</var> is <<compound-selector-list>> [=parsed as a forgiving selector list=].
 	If <var>S</var> is omitted,
 	it defaults to ''*|*''.
 
@@ -2954,6 +2957,9 @@ Child-indexed Pseudo-classes</h3>
 		</pre>
 	</div>
 
+	Note: We intend to extend '':nth-last-child()'' to accept <<complex-selector-list>>
+	in Level 5.
+
 <h4 id="the-first-child-pseudo">
 '':first-child'' pseudo-class</h4>
 
@@ -4038,6 +4044,8 @@ Changes since the 21 November 2018 Working Draft</h3>
 		<li>Defined '':is()'', '':where()'', '':has()'', '':nth-child()'', and '':nth-last-child()''
 			to not be themselves invalidated when containing an invalid selector.
 			(<a href="https://github.com/w3c/csswg-drafts/issues/3264">Issue 3264</a>)
+		<li>Limited selectors in '':nth-child()'' and '':nth-last-child()'' to [=compound selectors=] for now.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/3760">Issue 3760</a>)
 		<li>Clarified case-sensitive string matching by referencing string identity as defined in [[INFRA]].
 		<li>Clarified that UA-provided placeholder text still triggers '':placeholder-shown''.
 		<li>Rewrote '':focus-visible'' definition for clarity.