quite as great as it sounds, because, while we can refer to the
enumerator values outside the template, e.g.,
adder<long, 3, 4>::value
we can't yet refer to them with dependent names, so no Fibonacci
(yet).
InstantiateClassTemplateSpecialization is getting messy; next commit
will put it into a less-ugly state.
llvm-svn: 67092