Fix build on GHC 8.4 (#63)

* Fix haddock: postfix comments on GADT constructors don't work.

See https://github.com/haskell/haddock/issues/43 .

* Remove unused dependencies from cabal file..

* Semigroup instances for compatibility with GHC 8.4.

core/grpc-haskell-core.cabal

@@ -24,14 +24,7 @@ library
     , stm == 2.4.*
     , containers ==0.5.*
     , managed >= 1.0.0 && < 1.1
-    , pipes >=4.1 && <=4.4
     , transformers
-    , async ==2.1.*
-    , tasty >= 0.11 && <0.12
-    , tasty-hunit >= 0.9 && <0.10
-    , tasty-quickcheck >= 0.8.4 && < 0.9
-    , safe ==0.3.*
-    , vector
     , sorted-list >=0.1.6.1 && <=0.3
 
   c-sources:
@@ -87,7 +80,7 @@ test-suite tests
     , bytestring ==0.10.*
     , unix
     , time
-    , async
+    , async ==2.1.*
     , tasty >= 0.11 && <0.12
     , tasty-hunit >= 0.9 && <0.10
     , tasty-quickcheck >= 0.8.4 && < 0.9

core/src/Network/GRPC/Unsafe.chs

@@ -7,6 +7,7 @@ import Control.Exception (bracket)
 import Control.Monad
 
 import Data.ByteString (ByteString, useAsCString)
+import Data.Semigroup (Semigroup)
 
 import Foreign.C.String (CString, peekCString)
 import Foreign.Marshal.Alloc (free)
@@ -30,7 +31,7 @@ import Network.GRPC.Unsafe.Constants
 {#context prefix = "grpc" #}
 
 newtype StatusDetails = StatusDetails {unStatusDetails :: ByteString}
-  deriving (Eq, IsString, Monoid, Show)
+  deriving (Eq, IsString, Monoid, Semigroup, Show)
 
 {#pointer *grpc_completion_queue as CompletionQueue newtype #}
 

core/src/Network/GRPC/Unsafe/Metadata.chs

@@ -12,6 +12,7 @@ import Data.Function (on)
 import Data.ByteString (ByteString, useAsCString,
                         useAsCStringLen)
 import Data.List (sortBy, groupBy)
+import Data.Semigroup
 import qualified Data.SortedList as SL
 import qualified Data.Map.Strict as M
 import Data.Ord (comparing)
@@ -35,10 +36,13 @@ newtype MetadataMap = MetadataMap {unMap :: M.Map ByteString (SL.SortedList Byte
 instance Show MetadataMap where
   show m = "fromList " ++ show (M.toList (unMap m))
 
+instance Semigroup MetadataMap where
+  (MetadataMap m1) <> (MetadataMap m2) =
+    MetadataMap $ M.unionWith mappend m1 m2
+
 instance Monoid MetadataMap where
   mempty = MetadataMap $ M.empty
-  mappend (MetadataMap m1) (MetadataMap m2) =
+  mappend = (<>)
-    MetadataMap $ M.unionWith mappend m1 m2
 
 instance IsList MetadataMap where
   type Item MetadataMap = (ByteString, ByteString)

grpc-haskell.cabal

@@ -24,24 +24,12 @@ flag with-examples
 library
   build-depends:
       base >=4.8 && <5.0
-    , clock >=0.6.0 && <0.8.0
     , bytestring ==0.10.*
-    , stm == 2.4.*
-    , containers ==0.5.*
-    , managed >= 1.0.0 && < 1.1
-    , pipes >=4.1 && <=4.4
-    , transformers
     , proto3-suite
     , proto3-wire
     , grpc-haskell-core
 
     , async ==2.1.*
-    , tasty >= 0.11 && <0.12
-    , tasty-hunit >= 0.9 && <0.10
-    , tasty-quickcheck >= 0.8.4 && < 0.9
-    , safe ==0.3.*
-    , vector
-    , sorted-list >=0.1.6.1 && <=0.3
 
   exposed-modules:
     Network.GRPC.HighLevel

src/Network/GRPC/HighLevel/Client.hs

@@ -54,10 +54,10 @@ data ClientError
 data ClientRequest (streamType :: GRPCMethodType) request response where
   ClientNormalRequest :: request -> TimeoutSeconds -> MetadataMap -> ClientRequest 'Normal request response
   ClientWriterRequest :: TimeoutSeconds -> MetadataMap -> (StreamSend request -> IO ()) -> ClientRequest 'ClientStreaming request response
+  -- | The final field will be invoked once, and it should repeatedly
+  -- invoke its final argument (of type @(StreamRecv response)@)
+  -- in order to obtain the streaming response incrementally.
   ClientReaderRequest :: request -> TimeoutSeconds -> MetadataMap -> (MetadataMap -> StreamRecv response -> IO ()) -> ClientRequest 'ServerStreaming request response
-    -- ^ The final field will be invoked once, and it should repeatedly
-    -- invoke its final argument (of type @(StreamRecv response)@)
-    -- in order to obtain the streaming response incrementally.
   ClientBiDiRequest :: TimeoutSeconds -> MetadataMap -> (MetadataMap -> StreamRecv response -> StreamSend request -> WritesDone -> IO ()) -> ClientRequest 'BiDiStreaming request response
 
 data ClientResult (streamType :: GRPCMethodType) response where