Through a patch
https://git.haskell.org/ghc.git/commitdiff/aead01902e1c41e85b758dbafd15e60d0...
by Oleg Grenrus (phadej), GHC 8 will have the following new flags:
-fwarn-unused-top-binds
-fwarn-unused-local-binds
-fwarn-unused-pattern-binds
So you'll be able to pick and choose.
On Tue, Nov 3, 2015 at 6:47 PM, Evan Laforge
[ ccing haskell-cafe since while it's a ghc flag, I'll bet most compilers have an equivalent ]
I really like -fwarn-unused-binds because it frequently finds bugs where I forgot to call something or use some value. If I put an export list on, it can find dead functions I forgot to delete. However, there's one case where it frequently gives false positives, and that's unused record field names. The problem is that I sometimes use record field names as documentation, but the record itself is internal and small, so I'm comfortable using positional pattern matching to open it (and in fact that can be safer, since then warn-unused-binds will make sure I used all the fields). But GHC sees these as unused functions, so it warns about them. I can work around by putting underscores on field names I haven't used yet, but it's a hassle to go edit them when I want to use them. The warning can be useful if it indicates an unused field, but since fields can also be extracted via the positional syntax it's not reliable. The other use of the warning for dead code or functions you forgot to use doesn't apply to record accessors because they're trivial and compiler generated.
So, would it be reasonable to exclude record field accessors from -fwarn-unused-binds? Or is there another way to work around it? I guess GHC doesn't have a "suppress warning" pragma like Java does, but even if we did it wouldn't be much better than changing the name, and more likely to get stale. _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users