http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33101
--- Comment #14 from Keith Thompson <Keith.S.Thompson at gmail dot com> 2012-03-16 21:41:18 UTC --- On re-reading DR 577, I agree that it implies the current standard says that only "(void)" is allowed, and in particular that a typedef is not. I might have interpreted it differently myself, but I defer to the committee. (I thought perhaps that the change had been made between N3290 and the released standard, but apparently that's not the case.) The fact that C90 required the keyword further weakens my previous argument. So the diagnostic is necessary, but I'd still suggest that a warning would be more appropriate, and would still meet the current standard's requirements. (I should mention that I have no need for this myself; I don't even take advantage of the permission to use "(void)" rather than "()".)
