LWG2276 Missing requirement on std::promise::set_exception

Author: Dawn Perchik

source/threads.tex

@@ -3973,6 +3973,9 @@
 \end{itemdecl}
 
 \begin{itemdescr}
+\pnum
+\requires \tcode{p} is not null.
+
 \pnum
 \effects atomically stores the exception pointer \tcode{p} in the shared state
 and makes that state ready~(\ref{futures.state}).
@@ -4033,6 +4036,9 @@
 \end{itemdecl}
 
 \begin{itemdescr}
+\pnum
+\requires \tcode{p} is not null.
+
 \pnum
 \effects Stores the exception pointer \tcode{p} in the shared state without
 making that state ready immediately. Schedules that state to be made ready when