On Thu, Oct 31, 2019 at 1:31 PM David Blaikie <dblai...@gmail.com> wrote:
>
>
>
> On Thu, Oct 31, 2019 at 8:45 AM Aaron Ballman <aa...@aaronballman.com> wrote:
>>
>> On Wed, Oct 30, 2019 at 9:23 PM David Blaikie <dblai...@gmail.com> wrote:
>> >
>> > Two separate issues here
>> >
>> > 1) the fixit hint, as one of a set of alternatives, isn't likely to be
>> > removed/changed - the (albeit quirky) convention of using extra () to
>> > indicate an intentional assignment in a condition has been around for a
>> > while. So if you use the extra parens without writing an assignment, the
>> > compiler's going to suggest you resolve this "conflict" with the style -
>> > either you didn't intend the extra (), or you intended to use assignment.
>> > Those are the two alternative suggestions being made.
>> >
>> > 2) automatically applying one fixit hint of several ambiguous ones seems
>> > like a bug to me - Aaron - do you know anything about this? Is this
>> > accurate/intended/etc?
>>
>> I also think that's a bug. It looks like it's coming from
>> Sema::DiagnoseEqualityWithExtraParens(). It looks like it presents
>> both fixits, which strikes me as a bad thing to do when automatically
>> applying fixits.
>
>
> These fixits should be attached to notes, though, right? & Clang produces all
> sorts of fixits on notes that are not semantics-preserving, I think? ("oh, I
> think you meant to write this other thing")
Yes, they're both attached to notes but the notes point to the same
location as the error.
> My understanding is that the fixits are correct (in the clang diagnostic
> experience - "here's a warning, here are some ideas of what you might've
> intended that would address the warning") - but it seems incorrect to
> automatically apply especially ambiguous suggesitons like this. How would
> clang-tidy choose between the two alternatives?
I don't think it has a way to select between alternatives; I don't
think that was a use case we had envisioned for automatically applying
fix-its.
~Aaron
>
>>
>>
>> ~Aaron
>>
>> >
>> > On Tue, Oct 29, 2019 at 10:13 AM Robert Ankeney <rrank...@gmail.com> wrote:
>> >>
>> >> This was just a example of what I ran into when I used run-clang-tidy.py
>> >> across a compilation database with a -export-fixes=fix.yaml and then ra
>> >> clang-apply-replacements. Mainly I object to the suggestion+fixit to
>> >> switch to an assignment. Most coding standards would disallow assignments
>> >> in if conditionals. If anything, I would think a suggestion of "if (true
>> >> == isValid)" would be more appropriate.
>> >>
>> >> Thanks for the feedback!
>> >> Robert
>> >>
>> >> On Mon, Oct 28, 2019 at 2:17 PM David Blaikie <dblai...@gmail.com> wrote:
>> >>>
>> >>> clang-tidy in the command line you gave didn't seem to modify the file
>> >>> for me, did it modify the file for you?
>> >>>
>> >>> Are you objecting to the suggestion, or that it was automatically
>> >>> applied? I would think it'd be a bug to apply any fixit/hint if there
>> >>> are multiple possible suggestions.
>> >>>
>> >>> But the existence of the suggestion (without the application of it) to
>> >>> the user seems right to me. The use of extra () to suppress the
>> >>> assignment-in-conditional warning (-Wparentheses) has been around for
>> >>> quite a while, so it's possible that the user intended assignment rather
>> >>> than comparison when they added the extra parentheses.
>> >>>
>> >>> - Dave
>> >>>
>> >>> On Sun, Oct 27, 2019 at 11:32 AM Robert Ankeney via cfe-users
>> >>> <cfe-users@lists.llvm.org> wrote:
>> >>>>
>> >>>> For the following code (wrong.cpp):
>> >>>>
>> >>>> bool check(bool isValid)
>> >>>> {
>> >>>> bool retVal = false;
>> >>>>
>> >>>> if (( isValid == true ))
>> >>>> {
>> >>>> retVal = true;
>> >>>> }
>> >>>>
>> >>>> return retVal;
>> >>>> }
>> >>>>
>> >>>> when I run:
>> >>>> clang-tidy -checks=modernize-use-default-member-init wrong.cpp
>> >>>>
>> >>>> I get:
>> >>>> 4 warnings and 1 error generated.
>> >>>> Error while processing /llvm/match/ctBad/wrong.cpp.
>> >>>> /llvm/match/ctBad/wrong.cpp:5:19: error: equality comparison with
>> >>>> extraneous parentheses [clang-diagnostic-parentheses-equality]
>> >>>> if (( isValid == true ))
>> >>>> ~ ^~ ~
>> >>>> =
>> >>>> /llvm/match/ctBad/wrong.cpp:5:19: note: remove extraneous parentheses
>> >>>> around the comparison to silence this warning
>> >>>> /llvm/match/ctBad/wrong.cpp:5:19: note: use '=' to turn this equality
>> >>>> comparison into an assignment
>> >>>>
>> >>>> Note it turns the if into:
>> >>>> if ( isValid = true )
>> >>>>
>> >>>> Seems like a very bad idea. Removing the redundant parentheses seems
>> >>>> fine, but changing the comparison to an assignment does not. Is this a
>> >>>> bug?
>> >>>>
>> >>>> Thanks,
>> >>>> Robert
>> >>>>
>> >>>> _______________________________________________
>> >>>> cfe-users mailing list
>> >>>> cfe-users@lists.llvm.org
>> >>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-users
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