Re: [Haskell] Types of when and unless in Control.Monad

On Jun 06, 2012, at 08:44 AM, Andreas Abel wrote:

Well, but nothing in the type system prevents you from writing

mapM f xs >> cont

or

do mapM f xs cont

so you are not warned of a space leak in the common situations anyway,

At least the second form will trigger a warning in GHC (although admittedly not from the type system, but from -fwarn-unused-do-bind). It is a jolly useful warning at times. Regards, Malcolm