[Bug c++/59937] [constexpr] bogus diagnostic "used in its own initializer"

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59937

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Javier V. Gómez from comment #2)
> I found another case that worked in G++ 4.8.3 but fails in 4.9:

This example is complete nonsense. Why is it split across three files? Why
doesn't main.cpp include anything? Why is everything private? Why is 'a'
undeclared in B::foo()? Why does the diagnostic talk about 'ndims' which isn't
declared anywhere?

It's useless as a test or an example of the error.