Why GHC doesn't warn about LHS nullary-constructor pattern bindings?
lemming at henning-thielemann.de
Thu Jul 19 12:56:44 CEST 2012
On Thu, 19 Jul 2012, Herbert Valerio Riedel wrote:
> Recently, I was a bit suprised that GHC didn't warn about useless
> `where` definitions such as the following when using `-Wall` (and I
> couldn't find a respective warning GHC CLI flag which would have enabled
> reporting a warning in this case -- unless I missed it)
> module Foo where
> foo :: Int -> Int
> foo n = n + 1
> Nothing = Just n
I think that
x at Nothing = Just n
could be useful, if 'x' is evaluated somewhere.
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