[Haskell-cafe] Re: Predicativity?

Wei Hu weihu at cs.virginia.edu
Wed Sep 17 17:03:26 EDT 2008

Thomas Davie <tom.davie <at> gmail.com> writes:

> In your application (id id) you create two instances of id, each of  
> which has type forall a. a -> a, and each of which can be applied to a  
> different type.  In this case, the left one gets applied to the type  
> (a -> a) and the right one a, giving them types (a -> a) -> (a -> a)  
> and (a -> a) respectively.

Ah, I didn't realize it's because I created two instances of id, but it became 
clear immediately after you pointed this out. Thank you, Ryan and Thomas, for 
clarifying my confusion.


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