[Haskell-cafe] Can't Haskell catch up with Clean's uniqueness typing?

Hi all, being occupied with learning both languages, I'm getting curious if Haskell couldn't achieve most of the performance gains resulting from uniqueness typing in Clean by *automatically* determining the reference count of arguments wherever possible and subsequently allowing them to be physically replaced immediately by (the corresponding part of) the function's result. Are there any principal obstacles, or *could* this be done, or *is* this even done already, e. g. in ghc? Regards, zooloo -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.12/192 - Release Date: 05.12.2005