path: root/src/Propellor/Types/Dns.hs
diff options
authorJoey Hess2018-04-30 09:03:46 -0400
committerJoey Hess2018-04-30 09:03:46 -0400
commit14fe4c4d6b5a29be94ecfc0572e0f9a9a081e795 (patch)
tree38ad23b09bd21a8569568335a13bfde9c16e79c1 /src/Propellor/Types/Dns.hs
parent96ea8e04251bc23dd27faf1f486a2a9f9c29ff98 (diff)
fix broken SemigroupMonoid transition <<loop>>
Turns out that with ghc 8.2.2, the instructions given on the page don't work. And the cppless variant that I had compiles, but into effectively mappend = mappend so it loops. The only way I can see to make it work without cpp is to use mappend = (Sem.<>) which is ugly and a land mine waiting to explode if someone changes it to a nicer mappend = (<>) with a newer version of ghc which will compile it and work ok, while breaking it with 8.2.2. Sigh. I posted to haskell-cafe about this.
Diffstat (limited to 'src/Propellor/Types/Dns.hs')
1 files changed, 1 insertions, 1 deletions
diff --git a/src/Propellor/Types/Dns.hs b/src/Propellor/Types/Dns.hs
index 21a4860c..30302a7d 100644
--- a/src/Propellor/Types/Dns.hs
+++ b/src/Propellor/Types/Dns.hs
@@ -194,7 +194,7 @@ instance Sem.Semigroup NamedConfMap where
instance Monoid NamedConfMap where
mempty = NamedConfMap M.empty
- mappend = (<>)
+ mappend = (Sem.<>)
instance Empty NamedConfMap where
isEmpty (NamedConfMap m) = isEmpty m