Update to lts-12.10, support ghc 8.4, and aeson 1.3.

Don't fully understand the need for the MonoLocalBinds language extension,
which was not needed before but now ghc complains if it's not included,
but I've tested it and it does work.

All the rest of the changes are straightforward AMP changes and dep
updates.

Removed fgl from stack.yaml because it seems that indirect dep no longer
needs to be specified for stack to build.

Added custom-setup stanza since stack now warns without one.

This commit was sponsored by Trenton Cronholm on Patreon.

1 files changed, 5 insertions, 1 deletions

diff --git a/Types.hs b/Types.hs
index ce986c7..bbf296f 100644
--- a/Types.hs
+++ b/Types.hs
@@ -22,6 +22,7 @@ import JSON
 
 import qualified Data.Text as T
 import Data.Time.Clock.POSIX
+import qualified Data.Semigroup as Sem
 
 -- | Things that the developer sees.
 data Seen = Seen
@@ -194,9 +195,12 @@ newtype ElapsedTime = ElapsedTime Double
 mkElapsedTime :: POSIXTime -> POSIXTime -> ElapsedTime
 mkElapsedTime start end = ElapsedTime $ fromRational $ toRational (end - start)
 
+instance Sem.Semigroup ElapsedTime where
+	ElapsedTime a <> ElapsedTime b = ElapsedTime (a+b)
+
 instance Monoid ElapsedTime where
 	mempty = ElapsedTime 0
-	mappend (ElapsedTime a) (ElapsedTime b) = ElapsedTime (a+b)
+	mappend = (Sem.<>)
 
 instance DataSize ElapsedTime where
 	dataSize _ = 16 -- 128 bit Double