1 files changed, 14 insertions, 3 deletions
diff --git a/src/Language/GraphQL/Execute/Internal.hs b/src/Language/GraphQL/Execute/Internal.hs
index 3b75da1..792a758 100644
--- a/src/Language/GraphQL/Execute/Internal.hs
+++ b/src/Language/GraphQL/Execute/Internal.hs
@@ -3,23 +3,34 @@
    obtain one at https://mozilla.org/MPL/2.0/. -}
 
 {-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE ExplicitForAll #-}
 {-# LANGUAGE NamedFieldPuns #-}
 
 module Language.GraphQL.Execute.Internal
     ( addError
+    , singleError
     ) where
 
 import Control.Monad.Trans.State (modify)
 import Control.Monad.Catch (MonadCatch)
 import Data.Sequence ((|>))
-import Language.GraphQL.Error
+import Data.Text (Text)
 import Language.GraphQL.Execute.Coerce
+import Language.GraphQL.Error
+    ( CollectErrsT
+    , Error(..)
+    , Resolution(..)
+    , Response(..)
+    )
 import Prelude hiding (null)
 
-addError :: (Serialize a, MonadCatch m) => Error -> CollectErrsT m a
-addError error' = modify appender >> pure null
+addError :: MonadCatch m => forall a. a -> Error -> CollectErrsT m a
+addError returnValue error' = modify appender >> pure returnValue
   where
    appender :: Resolution m -> Resolution m
    appender resolution@Resolution{ errors } = resolution
        { errors = errors |> error'
        }
+
+singleError :: Serialize b => forall a. Text -> Either a (Response b)
+singleError message = Right $ Response null $ pure $ Error message [] []