add support for ghc-8

.travis.yml

@@ -10,6 +10,9 @@ matrix:
     - env: BUILD=tinc CABALVER=1.22 GHCVER=7.10.3
       compiler: ": #tinc 7.10.3"
       addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.3,happy-1.19.5], sources: [hvr-ghc]}}
+    - env: BUILD=tinc CABALVER=1.24 GHCVER=8.0.1
+      compiler: ": #tinc 8.0.1"
+      addons: {apt: {packages: [cabal-install-1.24,ghc-8.0.1,happy-1.19.5], sources: [hvr-ghc]}}
     - env: BUILD=stack GHCVER=7.10.3 STACK_YAML=stack.yaml
       compiler: ": #stack 7.10.3"
       addons: {apt: {packages: [ghc-7.10.3,happy-1.19.5], sources: [hvr-ghc]}}
@@ -19,7 +22,7 @@ matrix:
 
 before_install:
   - unset CC
-  - export PATH=/opt/ghc/$GHCVER/bin:/opt/cabal/1.22/bin:/opt/happy/1.19.5/bin:$PATH
+  - export PATH=/opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:/opt/happy/1.19.5/bin:$PATH
   - ./.travis-setup.sh
   - ghc --version || stack exec -- ghc --version
   - happy --version || true

src/Hpack/Config.hs

@@ -119,7 +119,7 @@ type FieldName = String
 class HasFieldNames a where
   fieldNames :: Proxy a -> [FieldName]
 
-  default fieldNames :: (HasTypeName a, Generic a, Selectors (Rep a)) => Proxy a -> [String]
+  default fieldNames :: (HasTypeName a, Selectors (Rep a)) => Proxy a -> [String]
   fieldNames proxy = map (hyphenize $ typeName proxy) (selectors proxy)
 
 data CaptureUnknownFields a = CaptureUnknownFields {

src/Hpack/GenericsUtil.hs

@@ -21,10 +21,10 @@ class HasTypeName a where
 instance (Datatype d, Generic a, Rep a ~ M1 D d m) => HasTypeName a where
   typeName _ = datatypeName (undefined :: M1 D d x y)
 
-selectors :: (Generic a, Selectors (Rep a)) => Proxy a -> [String]
+selectors :: (Selectors (Rep a)) => Proxy a -> [String]
 selectors = f
   where
-    f :: forall a. (Generic a, Selectors (Rep a)) => Proxy a -> [String]
+    f :: forall a. (Selectors (Rep a)) => Proxy a -> [String]
     f _ = selNames (Proxy :: Proxy (Rep a))
 
 class Selectors a where

test/Helper.hs

@@ -10,14 +10,14 @@ module Helper (
 import           Test.Hspec
 import           Test.Mockery.Directory
 import           Control.Applicative
-import           System.Directory
+import           System.Directory (getCurrentDirectory, setCurrentDirectory, canonicalizePath)
 import           Control.Exception
 import qualified System.IO.Temp as Temp
 import           System.FilePath
 
 withCurrentDirectory :: FilePath -> IO a -> IO a
 withCurrentDirectory dir action = do
-  bracket (getCurrentDirectory) (setCurrentDirectory) $ \ _ -> do
+  bracket getCurrentDirectory setCurrentDirectory $ \ _ -> do
     setCurrentDirectory dir
     action