Thanks, this is a known shortcoming. We'll either fix the docs or the
implementation!
--Sigbjorn
Sven Panne writes:
> GHC-3.01 can generate some really useful warnings, but some of those
> generated by -fwarn-unused-binds (which is switched on via -Wall, too)
> are plainly wrong. Silly, but short example:
>
..
> -- Foo.hs ----------------------
> module Foo(Bar(..)) where
>
> data Bar = MkBar
>
> instance Show Bar where
> showsPrec _ = baz
>
> baz :: Bar -> ShowS
> baz MkBar = showString "MkBar"
> -------------------------------
>
> panne@liesl:> ghc -fwarn-unused-binds -c Foo.hs
>
> Foo.hs:9: Warning: `baz' is bound but not used
>
> ghc: module version changed to 1; reason: no old .hi file
>
> GHC doesn't seem to take instance declarations into account when
> complaining... :-(
>
