[Bug c++/56556] Wshadow warns for private members in base classes

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56556

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2013-03-07 00:46:12 UTC ---
The main reason for the warning here is namelookup happens before access
control happens.  So even if change the name of x usage in Derived, you will
start to get weird error messages.