MonadFail proposal (MFP): Moving fail out of Monad

Johan Tibell johan.tibell at
Wed Jun 10 11:22:43 UTC 2015

On Wed, Jun 10, 2015 at 12:42 AM, David Luposchainsky <
dluposchainsky at> wrote:

> I think there are two important consequences of MonadFail. First of all,
> we can
> all safely write failable patterns if we so desire. Second, the compiler
> can
> ensure other people's codebases do not lie to us (knowingly or
> unknowingly).

The second is a bit overstated I think. Any function you call can still
have partial pattern matches in all the other places Haskell allows them
and you wouldn't know from the type.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Libraries mailing list