diff --git a/Language/Haskell/GhcMod/Monad.hs b/Language/Haskell/GhcMod/Monad.hs
index 36aabdd..44e9dd0 100644
--- a/Language/Haskell/GhcMod/Monad.hs
+++ b/Language/Haskell/GhcMod/Monad.hs
@@ -122,16 +122,6 @@ data CompilerMode = Simple | Intelligent deriving (Eq,Show,Read)
 defaultState :: GhcModState
 defaultState = GhcModState Simple
 
-data GhcModError = GMENoMsg
-                 | GMEString String
-                 | GMECabal
-                 | GMEGhc
-                   deriving (Eq,Show,Read)
-
-instance Error GhcModError where
-    noMsg = GMENoMsg
-    strMsg = GMEString
-
 ----------------------------------------------------------------
 
 -- | A constraint alias (-XConstraintKinds) to make functions dealing with
diff --git a/Language/Haskell/GhcMod/Types.hs b/Language/Haskell/GhcMod/Types.hs
index b42b018..5bab199 100644
--- a/Language/Haskell/GhcMod/Types.hs
+++ b/Language/Haskell/GhcMod/Types.hs
@@ -2,9 +2,24 @@ module Language.Haskell.GhcMod.Types where
 
 import Data.List (intercalate)
 import qualified Data.Map as M
+import Control.Monad.Error (Error(..))
 
 import PackageConfig (PackageConfig)
 
+-- |
+data GhcModError = GMENoMsg
+                 -- ^ Unknown error
+                 | GMEString String
+                 -- ^ Some Error with a message. These are produced mostly by
+                 -- 'fail' calls on GhcModT.
+                 | GMECabal String
+                 | GMEGhc
+                   deriving (Eq,Show,Read)
+
+instance Error GhcModError where
+    noMsg = GMENoMsg
+    strMsg = GMEString
+
 -- | Output style.
 data OutputStyle = LispStyle  -- ^ S expression style.
                  | PlainStyle -- ^ Plain textstyle.