-Wcast-qual consistency with initialization conversion and double pointer types

[Martin Uecker]

Am Montag, dem 17.06.2024 um 12:06 +0000 schrieb Joseph Myers:
> On Sun, 16 Jun 2024, Martin Uecker via Gcc wrote:
> 
> > I think it should not warn about:
> > 
> > char *x;
> > *(char * volatile *)&x;
> > 
> > as this is regular qualifier adding and this is
> > a bug in GCC.
> > 
> > I would guess it looks at all qualifiers added at
> > all level but should ignore the one on the first level.
> 
> This is meant to be implementing, as an extension to C, the C++ rules 
> (where converting from char** to const char** is unsafe, but converting 
> from char** to const char*const* is safe).  So the first question is what 
> C++ thinks of this conversion.
> 
Note that this is about the case where no third-level qualifier
is added. We should still warn about converting from char** to
const char **, and to volatile char ** but probably not (I think)
when converting to char*const*, const char*const*, 
volatile char*const*, and also not when converting
to char*volatile*.  So not when all intermediate casts
are const but also not when only a qualifier is added
to the second level but not to deeper levels. 

Martin