Re: [PATCH] PR c++/80544 strip cv-quals from cast results

[Jakub Jelinek <jakub at redhat dot com>]

On Thu, May 25, 2017 at 04:11:19PM +0200, Jakub Jelinek wrote:
> So, what can one do with typeof or similar to avoid the warning?
> 
> void
> foo (const void *p)
> {
>   const int *const q = (const int *const) p;
>   typeof (q) r = (typeof (q)) p;
>   (void) q;
>   (void) r;
> }
> 
> AFAIK typeof doesn't strip the toplevel qualifiers and I see current trunk
> warns even about the cast in r initialization.  Similarly to what has been
> noted recently in another (C) PR, it would be nice if we had toplevel cv
> stripping variant of typeof or some special builtin that could wrap
> typeof or some type and could be used in places where typeof can,
>   __strip_cv (typeof (q)) = (__strip_cv (typeof (q))) p;
> or
>   typeof (q) = (__strip_cv (typeof (q))) p;
> or
>   __strip_cv (const int *const) z;
> where the last one would be effectively
>   const int *z;

I guess in C++ one can use
  typeof (q) r = (remove_cv <typeof (q)>::type) p;
or something similar, but in C there is nothing like that.

	Jakub