Following up on review of patch2017.
1 patch for repository http://darcs.net/screened:
Author: Ben Franksen <email@example.com>
Date: Sun Jul 19 16:35:54 CEST 2020
* remove all MonadFail instances in darcs lib
The ones for the Perhaps type in the Prim.V1 and RepoPatchV1 implementations
were not used. The one for hopefullyM was also unneeded, in fact it turns
out that we only ever use it in the Maybe monad, so we change it to return
Maybe, simplifying the implementation as well.