[Haskell-cafe] Confused about type seen in the wild

[Andres Löh]

And even more:

Prelude> let test :: (Eq a, a, Eq b, b) => a; test = const
Prelude> :t test
test :: (Eq a, Eq b) => a -> b -> a
Prelude> let test :: (Eq a, Eq b, a, b) => a; test = const
Prelude> :t test
test :: (Eq a, Eq b) => a -> b -> a
Prelude> let test :: (a, b, Eq a, Eq b) => a; test = const

<interactive>:19:35:
    Predicate `a' used as a type
    In the type signature for `test': test :: (a, b, Eq a, Eq b) => a

Cheers,
  Andres

-- 
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com

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