LWG3990 Program-defined specializations of std::tuple and std::variant can't be properly supported

Editorial note: a new subclause [tuple.tuple.general] has been added
to avoid hanging paragraphs.

Author: burblebee

source/utilities.tex

@@ -1615,8 +1615,10 @@
 \end{itemdescr}
 
 \rSec2[tuple.tuple]{Class template \tcode{tuple}}
-\indexlibraryglobal{tuple}%
 
+\rSec3[tuple.tuple.general]{General}
+
+\indexlibraryglobal{tuple}%
 \begin{codeblock}
 namespace std {
   template<class... Types>
@@ -1742,6 +1744,10 @@
 }
 \end{codeblock}
 
+\pnum
+If a program declares an explicit or partial specialization of \tcode{tuple},
+the program is ill-formed, no diagnostic required.
+
 \rSec3[tuple.cnstr]{Construction}
 
 \pnum
@@ -5051,6 +5057,10 @@
 A program that instantiates the definition of \tcode{variant} with
 no template arguments is ill-formed.
 
+\pnum
+If a program declares an explicit or partial specialization of \tcode{variant},
+the program is ill-formed, no diagnostic required.
+
 \rSec3[variant.ctor]{Constructors}
 
 \pnum