[cfe-dev] Strange return value of Sema::CheckFunctionReturnType

Tue May 2 13:53:00 PDT 2017

On 2 May 2017 at 13:44, Keane, Erich via cfe-dev <cfe-dev at lists.llvm.org>
wrote:

>
>
> *From:* Reid Kleckner [mailto:rnk at google.com]
> *Sent:* Tuesday, May 2, 2017 1:17 PM
> *To:* Keane, Erich <erich.keane at intel.com>
> *Cc:* cfe-dev at lists.llvm.org; cfe-dev-request at lists.llvm.org;
> chenwj.cs97g at g2.nctu.edu.tw; mats at planetcatfish.com
> *Subject:* Re: [cfe-dev] Strange return value of
> Sema::CheckFunctionReturnType
>
>
>
> If this check can never fail and is cheap, we should just strengthen it to
> an assertion to check that GetFullTypeForDeclarator diagnoses this for us.
>
> *[Keane, Erich] Actually, I stand corrected…. There IS a case in our tests
> where it would hit such an assertion, though it didn’t hit my breakpoint
> when debugging.  I’ve never debugged ObjC before, so I must have just
> messed that up.*
>
>
>
> *That said, it IS hit in an existing test, though I’m not sure why the
> ‘return 0’ never caused an issue in the test.  I’ll note that it is also
> missing its FixItHint, which would likely have benefit to add.  I’ll toss a
> review on phabricator in a little bit that I’ll send to you all to take a
> look at.*
>

See http://clang.llvm.org/docs/InternalsManual.html#fix-it-hints

If you add a fixit to this error, Clang should recover as if the fixit were
applied, rather than bailing out.

> On Tue, May 2, 2017 at 10:03 AM, Keane, Erich via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
> I dug through this a bit.  It is pretty clearly a bug, however I was
> unable to get this line to actually be hit.  It seems that
> GetFullTypeForDeclarator gets called before this, and fails it first.  I'm,
> not sure HOW we could possibly reproduce this, since there doesn't seem to
> be a code path that would hit this before GetFullTypeForDeclarator.
>
> Perhaps it would be valid to fix it for 'correctness' sake, and forgive
> its lack of test?
>
> Message: 6
> Date: Tue, 2 May 2017 17:27:54 +0100
> From: mats petersson via cfe-dev <cfe-dev at lists.llvm.org>
> To: 陳韋任 <chenwj.cs97g at g2.nctu.edu.tw>
> Cc: Clang Dev <cfe-dev at lists.llvm.org>
> Subject: Re: [cfe-dev] Strange return value of
>         Sema::CheckFunctionReturnType
> Message-ID:
>         <CAL-htr72Ry1Mg3t=qLeTMeK3wg9XHMoFN+NTSvEwc+Nu-_psUg at mail.
> gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
>
> On 2 May 2017 at 16:08, 陳韋任 <chenwj.cs97g at g2.nctu.edu.tw> wrote:
>
> > 2017-05-02 22:41 GMT+08:00 mats petersson <mats at planetcatfish.com>:
> > > Looks like a bug to me. It should return `true`. I was going to say
> that
> > > it's a minor bug, (where `0` and `false` are possible to convert in
> > either
> > > direction, but it's actually returning an incorrect result.
> > >
> > > A patch to fix this, and adding a test-case would probably be
> > appreciated.
> >
> > Would be happy to. But I never use Objective-C, writing a test case would
> > be
> > hard to me...
> >
>
> Neither have I, but I'm pretty sure that it can't be TERRIBLY hard...
>
> --
> Mats
>
> >
> > --
> > Wei-Ren Chen (陳韋任)
> > Homepage: https://people.cs.nctu.edu.tw/~chenwj
> >
>
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