Re: [Haskell-cafe] Pointfree rank-2 typed function

Simon Peyton-Jones wrote:

It used to be, because GHC used to implement so-called "deep skolemisation". See Section 4.6.2 of http://research.microsoft.com/en-us/um/people/simonpj/papers/higher-rank/put...

Deep skolemisation was an unfortunate casualty of the push to add impredicative polymoprhism. However, as I mentioned in an earlier email, I'm currently planning to take impredicative polymorphism *out*, which means that deep skolemisation might come back *in*.

Are there workarounds for uses of impredicative types, or do we lose the ability to express certain programs as a result? Thanks, Martijn.