GHC's pattern-match overlap checker is a regular source of (justified) complaints. Somehow it never gets to the top of our agenda.
It's a well-identified piece of the compiler if anyone feels motivated to lend a hand. Otherwise I can't promise when we'll get to it. But keep prodding us at intervals if it is important to you. Maybe one of us will have a rush of blood to the head. Simon | -----Original Message----- | From: Feliks Kluzniak [mailto:[EMAIL PROTECTED]] | Sent: 09 March 2002 12:33 | To: [EMAIL PROTECTED] | Subject: warnings for pattern matches generated by the compiler | | | | Hello! | | I like to have the warnings about non-exhaustive pattern | matches etc. turned on: I find them very useful. | Unfortunately, this prevents me from taking full advantage of | field labels. | | Here is an (artificial) example: | | module See ( D, foo ) where | | data D = U | D{ value :: Int } | | foo :: D -> D | | foo d = case d | of | D{} -> d{ value = value d + 1 } | U -> D{ value = 0 } | | GHC complains as follows: | | ghc --make -odir../ghc -hidir../ghc -Wall | -fno-warn-missing-signatures See.hs | ghc-5.02.2: chasing modules from: See.hs | Compiling See ( See.hs, ../ghc/See.o ) | | See.hs:9: Warning: Pattern match(es) are non-exhaustive | In a record-update construct (D ds_dpd): Patterns not | matched: U | | This is not quite as it should be, is it? | | Is there any work-around other than abandoning the use of | field labels or turning off the warnings? (In my real | application there are quite a few more cases in the union, | and more fields.) | | Regards, | -- Feliks | _______________________________________________ | Glasgow-haskell-bugs mailing list | [EMAIL PROTECTED] | http://www.haskell.org/mailman/listinfo/glasgow-| haskell-bugs | _______________________________________________ Glasgow-haskell-bugs mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
