[Bug c++/55998] [4.8 Regression] [C++11] 'integral expression .. is not constant' when instantiating template alias in a template using a parameter of an encapsulating template

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55998

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2013-01-15 
21:56:24 UTC ---
Here is the full error message:
t6789.cc: In substitution of ‘template<int N> using B = A<N> [with int N = (4 -
1)]’:
t6789.cc:6:35:   required from ‘struct C<4>’
t6789.cc:9:19:   required from here
t6789.cc:6:35: error: integral expression ‘(4 - 1)’ is not constant
         template<typename T> void x(B<N-1>) {}
                                   ^
t6789.cc:6:35: error:   trying to instantiate ‘template<int N> using B = A<N>’