Possible runtime overhead of wrapping the IO monad?

[Brian Hulley]

Benjamin Franksen wrote:
> [snip]
> Thus, GHC does nothing wrong, according to the addendum. That doesn't
> mean allowing IO-equivalent newtypes wouldn't be a good idea. It is
> just not written in the addendum.

Apologies for not reading the addendum properly and slighting the good 
character of GHC... :-)
I've submitted a feature request that explains in more detail why I think it 
would be a good idea which can be read at 
http://hackage.haskell.org/trac/ghc/ticket/736

Regards, Brian.