[Haskell-cafe] Functional dependence nightmare

Stephen Tetley stephen.tetley at gmail.com
Sat Mar 26 21:19:45 CET 2011

Hi Edgar

What did you try?

My intuition is that this specific bit (there may be other problems)
is because the type checker is introducing a new type variable. Thus
you don't actually want the type operator (~) to say the new type
variable is equal to the type variable in the function signature, you
want to use scoped type variables so that the local type annotation is
*the same type* type variable.

Best wishes


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