diff --git a/ChangeLog.md b/ChangeLog.md
new file mode 100644
--- /dev/null
+++ b/ChangeLog.md
@@ -0,0 +1,6 @@
+# Revision history for constraints-extras
+
+## 0.2.3.4 - 2019-03-22
+
+* Added ChangeLog.md
+* Replaced some occurrences of <> in Data.Constraint.Extras.TH with ++ so that the module will hopefully build with GHC 8.0.2 and 8.2.2 without needing to import Data.Semigroup.
diff --git a/constraints-extras.cabal b/constraints-extras.cabal
--- a/constraints-extras.cabal
+++ b/constraints-extras.cabal
@@ -1,5 +1,5 @@
 name: constraints-extras
-version: 0.2.3.3
+version: 0.2.3.4
 synopsis: Utility package for constraints
 description: Convenience functions and TH for working with constraints. See <https://github.com/obsidiansystems/constraints-extras/blob/develop/README.md README.md> for example usage.
 category: Constraints
@@ -11,6 +11,7 @@
 build-type: Simple
 cabal-version: >=2.0
 extra-source-files: README.md
+                    ChangeLog.md
 
 library
   exposed-modules: Data.Constraint.Extras
diff --git a/src/Data/Constraint/Extras/TH.hs b/src/Data/Constraint/Extras/TH.hs
--- a/src/Data/Constraint/Extras/TH.hs
+++ b/src/Data/Constraint/Extras/TH.hs
@@ -4,24 +4,20 @@
 module Data.Constraint.Extras.TH (deriveArgDict, deriveArgDictV, gadtIndices) where
 
 import Data.Constraint.Extras
-import Control.Monad
 import Data.Constraint
+import Data.Either
 import Data.Maybe
+import Control.Monad
 import Language.Haskell.TH
 
-import Data.Either
 
 deriveArgDict :: Name -> Q [Dec]
 deriveArgDict n = do
   ts <- gadtIndices n
   c <- newName "c"
-  g <- newName "g"
   let xs = flip map ts $ \case
         Left t -> AppT (AppT (ConT ''ConstraintsFor) t) (VarT c)
         Right t -> (AppT (VarT c) t)
-      xs' = flip map ts $ \case
-        Left t -> AppT (AppT (AppT (ConT ''ConstraintsFor') t) (VarT c)) (VarT g)
-        Right t -> AppT (VarT c) (AppT (VarT g) t)
       l = length xs
       constraints = foldl AppT (TupleT l) xs
   arity <- tyConArity n
@@ -62,8 +58,8 @@
             in [Match (ConP name pat) (NormalB $ AppE (VarE argDictName) (VarE v)) []]
       ForallC _ _ (GadtC [name] _ _) -> return $
         [Match (RecP name []) (NormalB $ ConE 'Dict) []]
-      a -> error $ "deriveArgDict matches: Unmatched 'Dec': " <> show a
-    a -> error $ "deriveArgDict matches: Unmatched 'Info': " <> show a
+      a -> error $ "deriveArgDict matches: Unmatched 'Dec': " ++ show a
+    a -> error $ "deriveArgDict matches: Unmatched 'Info': " ++ show a
 
 kindArity :: Kind -> Int
 kindArity = \case
@@ -76,7 +72,7 @@
 tyConArity :: Name -> Q Int
 tyConArity n = reify n >>= return . \case
    TyConI (DataD _ _ ts mk _ _) -> fromMaybe 0 (fmap kindArity mk) + length ts
-   _ -> error $ "tyConArity: Supplied name reified to something other than a data declaration: " <> show n
+   _ -> error $ "tyConArity: Supplied name reified to something other than a data declaration: " ++ show n
 
 gadtIndices :: Name -> Q [Either Type Type]
 gadtIndices n = reify n >>= \case
@@ -89,4 +85,4 @@
       _ -> return []
     ForallC _ _ (GadtC _ _ (AppT _ typ)) -> return [Right typ]
     _ -> return []
-  a -> error $ "gadtResults: Unmatched 'Info': " <> show a
+  a -> error $ "gadtResults: Unmatched 'Info': " ++ show a