[Haskell-cafe] type variable question

Simon Peyton-Jones simonpj at microsoft.com
Thu Dec 14 04:22:24 EST 2006

| The commented out signature is the signature that GHC infers for the
| function. When I uncomment that signature, it will no longer type
| check. Why does this happen? Even with the forall and the explicit
| signatures in the where clause, it chokes.

This very question is one that came up only yesterday

Could you boil out a small example?  A good way to shrink code is to replace a function that is not playing a significant role with an error call: replace
        f :: <type>
        f = <big rhs>
        f :: <type>
        f = error "urk"

Usually that lets you get a small example.  But if you can't, just send the whole thing


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