[commit: ghc] master: document the plan for removing Data.Semigroup.Option (90589a9)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/90589a942b770b9c373a73b6c1d17487fdcf4d9b/ghc

>---------------------------------------------------------------

commit 90589a942b770b9c373a73b6c1d17487fdcf4d9b
Author: Andrew Martin <andrew.thaddeus at gmail.com>
Date:   Wed Apr 25 19:44:29 2018 -0400

    document the plan for removing Data.Semigroup.Option


>---------------------------------------------------------------

90589a942b770b9c373a73b6c1d17487fdcf4d9b
 libraries/base/Data/Semigroup.hs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libraries/base/Data/Semigroup.hs b/libraries/base/Data/Semigroup.hs
index 4438e2f..58a0b92 100644
--- a/libraries/base/Data/Semigroup.hs
+++ b/libraries/base/Data/Semigroup.hs
@@ -455,7 +455,12 @@ mtimesDefault n x
 -- underlying 'Monoid'.
 --
 -- Ideally, this type would not exist at all and we would just fix the
--- 'Monoid' instance of 'Maybe'
+-- 'Monoid' instance of 'Maybe'.
+--
+-- In GHC 8.4 and higher, the 'Monoid' instance for 'Maybe' has been
+-- corrected to lift a 'Semigroup' instance instead of a 'Monoid'
+-- instance. Consequently, this type is no longer useful. It will be
+-- marked deprecated in GHC 8.8 and removed in GHC 8.10.
 newtype Option a = Option { getOption :: Maybe a }
   deriving ( Eq       -- ^ @since 4.9.0.0
            , Ord      -- ^ @since 4.9.0.0