[PATCH] D67919: [Diagnostics] Warn if enumeration type mismatch in conditional expression

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman accepted this revision.
aaron.ballman added a comment.
This revision is now accepted and ready to land.

LGTM aside from a commenting request.



================
Comment at: test/Sema/warn-conditional-emum-types-mismatch.c:19
+
+int get_flag_anon_enum(int cond) {
+  return cond ? A : C;
----------------
xbolva00 wrote:
> aaron.ballman wrote:
> > xbolva00 wrote:
> > > Gcc warns here, but Clang does not warn when A != C..
> > > 
> > > So not sure here..
> > My gut reaction is that I think Clang should warn here as well because the code pattern is confusing, but I'd also say that if there's a lot of false positives where the code is sensible, it may make sense to suppress the diagnostic. One situation I was thinking of where you could run into something like this is:
> > ```
> > enum {
> >   STATUS_SUCCESS,
> >   STATUS_FAILURE,
> >   ...
> >   MAX_BASE_STATUS_CODE
> > };
> > 
> > enum ExtendedStatusCodes {
> >   STATUS_SOMETHING_INTERESTING = MAX_BASE_STATUS_CODE + 1000,
> >   ...
> > };
> > 
> > int whatever(void) {
> >   return some_condition() ? STATUS_SOMETHING_INTERESTING : STATUS_SUCCESS;
> > }
> > ```
> +1
Can you add some comments to the test case explaining that we purposefully differ from GCC here and why?


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