[Bug c++/44673] static const variable works in if/else, fails at linking in ternary

[redi at gcc dot gnu dot org]

------- Comment #15 from redi at gcc dot gnu dot org  2010-06-26 13:46 -------
(In reply to comment #14)
> 
> However, it links in the if-else case.

The variable is not "used" in the [basic.def.odr] sense, because the
lvalue-to-rvalue conversion occurs immediately.

> I understand that ?: may be used as a
> lvalue, but in this case, it is not and the value may be inlined in the same
> way as in if-else (I guess that is what Andrew's patch did). If the standard is
> clear that this should not work, then so be it. 

The lvalue-to-rvalue conversion doesn't happen immediately to either the second
or third operand, it happens to the result of the conditional expression.

Andrew's idea might be allowed by the as-if rule, but I'm not sure. It must not
change the behaviour of valid programs. And in any case, the original example
is invalid. Supporting it is not important IMHO.

> Let's close this as INVALID, because I don't know how we could improve the
> diagnostics here to help users. I wish we could but I cannot see how it can be
> done. I guess that would require an integrated super-smart linker, I wonder if
> the LLVM project is going to suggest that next?

closing again


-- 

redi at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44673