Re: [PATCH] casts should drop qualifiers

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

On Wed, Nov 18, 2020 at 11:51:00AM -0800, Linus Torvalds wrote:
> On Wed, Nov 18, 2020 at 11:17 AM Luc Van Oostenryck
> <luc.vanoostenryck@gmail.com> wrote:
> >
> > I don't think it's a good idea. The focus now is all about dropping
> > the qualifiers but in code like:
> >         const int x;
> >         typeof(c) y;
> > don't we want 'y' to also have the type 'const int'?
> 
> I assume you meant "typeof(x)". But yes, absolutely.

Yes, sure.
 
> Which is why my suggested example patch had that explicit test for
> "is_lvalue()".  So only for non-lvalues would it strip the qualifiers.
> 
> So "typeof(((void)0,x)) y;" would be "int", because that expression
> inside the typeof isn't an lvalue.

Oh yes, sorry. For some reasons I had things upside down.
 
> But if you have something that is already doing the generic case, then
> that's obviously better. My suggestion was more of a "we can zero in
> on just that typeof case" thing.

I just sent the series but it's not generic.

If I read the standard correctly (big 'if'), in:
	volatile int x;
	typeof(++x) y;
'y' should have the type 'volatile int' and GCC interpret it so.

-- Luc