[PATCH]: Implementation of -Wcast-qual

[David Blaikie]

[+Richard for oversight]

char **y1 = (char **)ptrptr; // expected-warning {{cast from 'const char
*const *' to 'char **' drops const qualifier}} expected-warning {{cast from
'const char *const' to 'char *' drops const qualifier}}

I think if we're going to warn on multiple layers (I'm not sure that's
ideal - is that consistent with GCC's warning? Does GCC warn on mismatched
types too - "const T*" -> "U*"? - do we warn there too, or only when
there's a valid implicit conversion like the void* example?) then we should
probably drop the top level const, "const char *const" -> "char*" - the top
level const on the first type is confusing/misleading, it's only relevant
to show "const char*" and "char*".


On Wed, Nov 12, 2014 at 10:41 AM, Roman Divacky <rdivacky at vlakno.cz> wrote:

> I expanded the testcase and fixed the grammar in the actual warning.
>
> New patch attached.
>
> On Tue, Nov 11, 2014 at 05:03:33PM -0800, David Blaikie wrote:
> > (it's a bit easier if you include the test in the same patch file - also
> > you can use Phabricator if you like - some reviewers perefer it)
> >
> > Since you've got the loop there for seeing through multiple levels of
> > pointer, should you have a test case that exercises that on a > 1 level
> of
> > depth? Demonstrate that we warn on both levels (if that's the right thing
> > to do?)?
> >
> > Optionally (probably in a separate follow-up patch) you could add a note
> > with a fixit to include the missing consts.
> >
> > On Tue, Nov 11, 2014 at 10:58 AM, Roman Divacky <rdivacky at vlakno.cz>
> wrote:
> >
> > > Hi,
> > >
> > > I implemented -Wcast-qual. The patch is actually quite short (attached
> + a
> > > test
> > > case).
> > >
> > > This fixes #13772 and also note that -Wcast-qual is used in llvm build
> > > itself.
> > >
> > > Is this ok to be commited? Thanks
> > >
> > > Roman
> > >
> > >
> > > _______________________________________________
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> > >
> > >
>
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