[Bug c++/62182] New warning wished: operator== and "equality comparison result unused [-Wunused-comparison]"/-Wunsed-value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62182 egallager at gcc dot gnu.org changed: What|Removed |Added Status|NEW |RESOLVED CC||egallager at gcc dot gnu.org Resolution|--- |DUPLICATE --- Comment #7 from egallager at gcc dot gnu.org --- (In reply to Eric Gallager from comment #6) > I think this is a duplicate of bug 53598 Closing as a duplicate of it *** This bug has been marked as a duplicate of bug 53598 ***
[Bug c++/62182] New warning wished: operator== and "equality comparison result unused [-Wunused-comparison]"/-Wunsed-value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62182 Eric Gallager changed: What|Removed |Added CC||egall at gwmail dot gwu.edu --- Comment #6 from Eric Gallager --- I think this is a duplicate of bug 53598
[Bug c++/62182] New warning wished: operator== and "equality comparison result unused [-Wunused-comparison]"/-Wunsed-value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62182 --- Comment #5 from Marek Polacek --- (In reply to Arnaud Bienner from comment #3) > One thing that doesn't work is turning on this warning using > -Wunused-comparison parameter. But surprisingly, turning it off with > -Wno-unused-comparison (when -Wunused or -Wall is used) works. Not sure what > I'm missing here. Because the emit_side_effect_warnings calls are guarded by warn_unused_value.
[Bug c++/62182] New warning wished: operator== and "equality comparison result unused [-Wunused-comparison]"/-Wunsed-value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62182 --- Comment #4 from Manuel López-Ibáñez --- (In reply to Arnaud Bienner from comment #3) > Created attachment 35324 [details] > unused-comparison warning You need testcases, and to run the testsuite. See point 4 at: https://gcc.gnu.org/wiki/GettingStarted#Basics:_Contributing_to_GCC_in_10_easy_steps > One thing that doesn't work is turning on this warning using > -Wunused-comparison parameter. But surprisingly, turning it off with > -Wno-unused-comparison (when -Wunused or -Wall is used) works. Not sure what > I'm missing here. That is very weird. I don't see anything wrong in your patch about this. Nonetheless, please add the warning to c-family/c.opt not to common.opt since it is a C/C++ warning. Also watch out for the formatting (too long lines, incorrect indentation, etc.) See point 6 in the link above. > The patch would just be a first step: the next step would be to also raise > this warning in the case of a "==" operator overloading in C++ (which seems > to be the case that doesn't raise a warning currently). Not sure yet how to > do this. It is more than ok to do one patch per step. Try to get the first patch right and committed, then worry about the next.
[Bug c++/62182] New warning wished: operator== and "equality comparison result unused [-Wunused-comparison]"/-Wunsed-value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62182 --- Comment #3 from Arnaud Bienner --- Created attachment 35324 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35324&action=edit unused-comparison warning I also believe it can be useful to have "unused comparison" warning (i.e. something more specific than current "unused value" warning, because they are likely to be typo. Having a dedicated warning will allow people who want to activate this warning specifically and/or to turn it into an error. So I started to have a look at this and I would like to have some feedback from someone more experienced. It's my first patch to gcc, so it is probably not perfect. One thing that doesn't work is turning on this warning using -Wunused-comparison parameter. But surprisingly, turning it off with -Wno-unused-comparison (when -Wunused or -Wall is used) works. Not sure what I'm missing here. The patch would just be a first step: the next step would be to also raise this warning in the case of a "==" operator overloading in C++ (which seems to be the case that doesn't raise a warning currently). Not sure yet how to do this.
[Bug c++/62182] New warning wished: operator== and "equality comparison result unused [-Wunused-comparison]"/-Wunsed-value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62182 Arnaud Bienner changed: What|Removed |Added CC||arnaud.bienner at ensimag dot fr --- Comment #2 from Arnaud Bienner --- Related bug: bug 53598.
[Bug c++/62182] New warning wished: operator== and "equality comparison result unused [-Wunused-comparison]"/-Wunsed-value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62182 Manuel López-Ibáñez changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2015-02-28 CC||manu at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from Manuel López-Ibáñez --- I'm going to confirm this because we obviously want it.
