[Bug c++/53596] g++-4.7 -Wall shouldn't complain for non-virtual protected dtor

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53596

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-06-06 
22:45:00 UTC ---
The reason previous versions of GCC do not warn is because GCC has been
improved and now issues a warning for unsafe code that it didn't diagnose
before. This is a good thing.