Move path to the execution error

Since it isn't possible to get a path during validation, without
executing the query.

src/Language/GraphQL/Validate/Validation.hs

@@ -5,7 +5,6 @@
 -- | Definitions used by the validation rules and the validator itself.
 module Language.GraphQL.Validate.Validation
     ( Error(..)
-    , Path(..)
     , Rule(..)
     , RuleT
     , Validation(..)
@@ -14,25 +13,14 @@ module Language.GraphQL.Validate.Validation
 import Control.Monad.Trans.Reader (ReaderT)
 import Data.HashMap.Strict (HashMap)
 import Data.Sequence (Seq)
-import Data.Text (Text)
 import Language.GraphQL.AST.Document
 import Language.GraphQL.Type.Schema (Schema)
 import qualified Language.GraphQL.Type.Schema as Schema
 
--- | If an error can be associated to a particular field in the GraphQL result,
--- it must contain an entry with the key path that details the path of the
--- response field which experienced the error. This allows clients to identify
--- whether a null result is intentional or caused by a runtime error.
-data Path
-    = Segment Text -- ^ Field name.
-    | Index Int -- ^ List index if a field returned a list.
-    deriving (Eq, Show)
-
 -- | Validation error.
 data Error = Error
     { message :: String
     , locations :: [Location]
-    , path :: [Path]
     } deriving (Eq, Show)
 
 -- | Validation rule context.