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authorDavid Luposchainsky <dluposchainsky@gmail.com>2015-11-29 22:59:57 +0100
committerBen Gamari <ben@smart-cactus.org>2015-11-29 23:00:48 +0100
commit290def72f54db7969258b4541aaefc87b54ce448 (patch)
tree5843028d9666626e3becb897e21e8caa007fd8c2 /compiler/utils/UniqFM.hs
parentbcd55a94f234f5efa4bb4fd24429dafc79d93106 (diff)
downloadhaskell-290def72f54db7969258b4541aaefc87b54ce448.tar.gz
Implement warnings for Semigroups as parent of Monoid
This patch is similar to the AMP patch (#8004), which offered two functions: 1. Warn when an instance of a class has been given, but the type does not have a certain superclass instance 2. Warn when top-level definitions conflict with future Prelude names These warnings are issued as part of the new `-Wcompat` warning group. Reviewers: hvr, ekmett, austin, bgamari Reviewed By: hvr, ekmett, bgamari Subscribers: ekmett, thomie Differential Revision: https://phabricator.haskell.org/D1539 GHC Trac Issues: #11139
Diffstat (limited to 'compiler/utils/UniqFM.hs')
-rw-r--r--compiler/utils/UniqFM.hs9
1 files changed, 9 insertions, 0 deletions
diff --git a/compiler/utils/UniqFM.hs b/compiler/utils/UniqFM.hs
index db578c37d0..fa556fb2b1 100644
--- a/compiler/utils/UniqFM.hs
+++ b/compiler/utils/UniqFM.hs
@@ -84,6 +84,10 @@ import Data.Data
#if __GLASGOW_HASKELL__ < 709
import Data.Monoid
#endif
+#if __GLASGOW_HASKELL__ > 710
+import Data.Semigroup ( Semigroup )
+import qualified Data.Semigroup as Semigroup
+#endif
{-
************************************************************************
@@ -202,6 +206,11 @@ ufmToList :: UniqFM elt -> [(Unique, elt)]
************************************************************************
-}
+#if __GLASGOW_HASKELL__ > 710
+instance Semigroup (UniqFM a) where
+ (<>) = plusUFM
+#endif
+
instance Monoid (UniqFM a) where
mempty = emptyUFM
mappend = plusUFM