This implements phase 1 of the MonadFail proposal (MFP, Trac #10751).
- MonadFail warnings are all issued as desired, tunable with two new flags
- GHC was *not* made warning-free with -fwarn-missing-monadfail-warnings (but it's disabled by default right now)
- Franz Thoma, whose help was crucial to implementing this
- My employer TNG Technology Consulting GmbH for partially funding us for this work