[PATCH 1/3] Rewrite valid-expr.h's internals in terms of the detection idiom (C++17/N4502)

[Pedro Alves]

On 9/29/20 2:04 PM, Tom Tromey wrote:
>>>> I'm not sure if it was exactly this patch, but after I merged this code
>>>> to our internal tree, we started having build problems on a machine that
>>>> uses GCC 6.4.  I've appended the error message.
>>>> I'm not sure it is worth doing anything about this, but I thought it
>>>> would be worth noting in case anybody else winds up in this situation.
>>>> Tom
> 
> Luis> It was reported before on this thread a week or so ago. Unless GCC 6.4
> Luis> isn't supported any longer, I think it should be fixed.
> 
> Tom> Ok, thanks.  I will find out tonight.
> 
> Oops, I really misunderstood your note, and re-reading it now I can't
> really understand why.  I thought you were saying it was fixed, but
> really you were saying it is still there and should be fixed if we want
> to support GCC 6.4.
> 
> I am not sure if we should try to fix it or not.  Locally I plan to
> disable unit tests on this particular machine.  It is the only one using
> 6.4.

I built a GCC 6.4 here, and could reproduce it.  I'm testing a fix.