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| author | Herbert Valerio Riedel <hvr@gnu.org> | 2018-08-06 12:53:06 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2018-08-07 15:56:53 -0400 |
| commit | aab8656ba0561e56048a1222c396d2d117aca5a7 (patch) | |
| tree | 8d14345e7f042ba5700b4275950e44dcc0ca1be9 /docs/users_guide/8.6.1-notes.rst | |
| parent | f22baa424aed66cd75ea05d4db7efdcd0e021217 (diff) | |
| download | haskell-aab8656ba0561e56048a1222c396d2d117aca5a7.tar.gz | |
Turn on MonadFail desugaring by default
Summary:
This contains two commits:
----
Make GHC's code-base compatible w/ `MonadFail`
There were a couple of use-sites which implicitly used pattern-matches
in `do`-notation even though the underlying `Monad` didn't explicitly
support `fail`
This refactoring turns those use-sites into explicit case
discrimations and adds an `MonadFail` instance for `UniqSM`
(`UniqSM` was the worst offender so this has been postponed for a
follow-up refactoring)
---
Turn on MonadFail desugaring by default
This finally implements the phase scheduled for GHC 8.6 according to
https://prime.haskell.org/wiki/Libraries/Proposals/MonadFail#Transitionalstrategy
This also preserves some tests that assumed MonadFail desugaring to be
active; all ghc boot libs were already made compatible with this
`MonadFail` long ago, so no changes were needed there.
Test Plan: Locally performed ./validate --fast
Reviewers: bgamari, simonmar, jrtc27, RyanGlScott
Reviewed By: bgamari
Subscribers: bgamari, RyanGlScott, rwbarton, thomie, carter
Differential Revision: https://phabricator.haskell.org/D5028
Diffstat (limited to 'docs/users_guide/8.6.1-notes.rst')
| -rw-r--r-- | docs/users_guide/8.6.1-notes.rst | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/docs/users_guide/8.6.1-notes.rst b/docs/users_guide/8.6.1-notes.rst index 3a24384493..7faef04516 100644 --- a/docs/users_guide/8.6.1-notes.rst +++ b/docs/users_guide/8.6.1-notes.rst @@ -134,6 +134,11 @@ Language See :ghc-ticket:`13833`. +- :extension:`MonadFailDesugaring` is now enabled by default. See + `MonadFail Proposal (MFP) + <https://prime.haskell.org/wiki/Libraries/Proposals/MonadFail>`__ + for more details. + Compiler ~~~~~~~~ |