[Haskell-cafe] Definition of hidden instance members (bug in GHC or Hugs+Yhc)

Neil Mitchell ndmitchell at gmail.com
Sat Jul 5 19:00:07 EDT 2008


This is either a GHC bug, or a Yhc+Hugs bug - I'm not sure which, but
the compilers disagree:

import Prelude hiding ((==))
data Foo = Foo
instance Eq Foo where
    (==) a b = True

GHC says:
Temp.hs:14:4: `==' is not a (visible) method of class `Eq'

Yhc and Hugs both successfully compile the module.

Does anyone know which compiler(s) are in the wrong, and need bugs filing?



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