=over 4
-=item A thread exited while %d other threads were still running
+=item A thread exited while %d threads were running
(W) When using threaded Perl, a thread (not necessarily the main
thread) exited while there were still other threads running.
(F) The failing code has attempted to get or set a key which is not in
the current set of allowed keys of a restricted hash.
-=item Attempt to clear a restricted hash
-
-(F) It is currently not allowed to clear a restricted hash, even if the
-new hash would contain the same keys as before. This may change in
-the future.
-
=item Attempt to delete readonly key '%s' from a restricted hash
(F) The failing code attempted to delete a key whose value has been
generally because there's a better way to do it, and also because the
old way has bad side effects.
+=item Use of freed value in iteration (perhaps you modified the iterated array within the loop?)
+
+(F) This is typically caused by code like the following:
+
+ @a = (3,4);
+ @a = () for (1,2,@a);
+
+You are not supposed to modify arrays while they are being iterated over.
+For speed and efficiency reasons, Perl internally does not do full
+reference-counting of iterated items, hence deleting such an item in the
+middle of an iteration causes Perl to see a freed value.
+
=item Use of reference "%s" as array index
(W misc) You tried to use a reference as an array index; this probably