diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,21 @@
 and this project adheres to
 [Haskell Package Versioning Policy](https://pvp.haskell.org/).
 
+## [1.2.0.0] - 2023-02-28
+### Added
+- Schema printing.
+- `Semigroup` and `Monoid` instances for `AST.Document.Description`.
+- Support for vector 0.13.0.0 and transformers 0.6.1.0.
+
+### Fixed
+- Fix resolvers returning a list in the reverse order.
+
+### Removed
+- GHC 8 support.
+- Cabal -json flag.
+- `Test.Hspec.GraphQL`: moved to `graphql-spice` package.
+- CPP `ifdef WITH_JSON` blocks.
+
 ## [1.1.0.0] - 2022-12-24
 ### Changed
 - Removed deprecated `Language.GraphQL.Error` functions: `addErr`, `addErrMsg`,
@@ -490,6 +505,7 @@
 ### Added
 - Data types for the GraphQL language.
 
+[1.2.0.0]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=v1.2.0.0&rev_to=v1.1.0.0
 [1.1.0.0]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=v1.1.0.0&rev_to=v1.0.3.0
 [1.0.3.0]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=v1.0.3.0&rev_to=v1.0.2.0
 [1.0.2.0]: https://www.caraus.tech/projects/pub-graphql/repository/23/diff?rev=v1.0.2.0&rev_to=v1.0.1.0
diff --git a/graphql.cabal b/graphql.cabal
--- a/graphql.cabal
+++ b/graphql.cabal
@@ -1,7 +1,7 @@
 cabal-version: 2.4
 
 name:           graphql
-version:        1.1.0.0
+version:        1.2.0.0
 synopsis:       Haskell GraphQL implementation
 description:    Haskell <https://spec.graphql.org/June2018/ GraphQL> implementation.
 category:       Language
@@ -11,7 +11,7 @@
                 Matthías Páll Gissurarson <mpg@mpg.is>,
                 Sólrún Halla Einarsdóttir <she@mpg.is>
 maintainer:     belka@caraus.de
-copyright:      (c) 2019-2022 Eugen Wissner,
+copyright:      (c) 2019-2023 Eugen Wissner,
                 (c) 2015-2017 J. Daniel Navarro
 license:        MPL-2.0 AND BSD-3-Clause
 license-files:  LICENSE,
@@ -21,18 +21,12 @@
   CHANGELOG.md
   README.md
 tested-with:
-  GHC == 8.10.7,
-  GHC == 9.2.4
+  GHC == 9.2.5
 
 source-repository head
   type: git
   location: git://caraus.tech/pub/graphql.git
 
-flag Json
-  description: Whether to build against @aeson 1.x@
-  default: False
-  manual: True
-
 library
   exposed-modules:
     Language.GraphQL
@@ -53,7 +47,6 @@
     Language.GraphQL.Type.Schema
     Language.GraphQL.Validate
     Language.GraphQL.Validate.Validation
-    Test.Hspec.GraphQL
   other-modules:
     Language.GraphQL.Execute.Transform
     Language.GraphQL.Type.Definition
@@ -72,15 +65,9 @@
     parser-combinators >= 1.3 && < 2,
     template-haskell >= 2.16 && < 3,
     text >= 1.2 && < 3,
-    transformers ^>= 0.5.6,
+    transformers >= 0.5.6 && < 0.7,
     unordered-containers ^>= 0.2.14,
-    vector ^>= 0.12.3
-  if flag(Json)
-    build-depends:
-      aeson >= 1.5.6 && < 1.6,
-      hspec-expectations >= 0.8.2 && < 0.9,
-      scientific >= 0.3.7 && < 0.4
-    cpp-options: -DWITH_JSON
+    vector >= 0.12 && < 0.14
 
   default-language: Haskell2010
 
@@ -110,7 +97,7 @@
     conduit,
     exceptions,
     graphql,
-    hspec ^>= 2.9.1,
+    hspec ^>= 2.10.9,
     hspec-expectations ^>= 0.8.2,
     hspec-megaparsec ^>= 2.2.0,
     megaparsec,
diff --git a/src/Language/GraphQL.hs b/src/Language/GraphQL.hs
--- a/src/Language/GraphQL.hs
+++ b/src/Language/GraphQL.hs
@@ -1,111 +1,11 @@
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RecordWildCards #-}
 
-#ifdef WITH_JSON
 -- | This module provides the functions to parse and execute @GraphQL@ queries.
---
--- The content of this module depends on the value of the __json__ flag, which
--- is currently on by default. This behavior will change in the future, the flag
--- will be switched off by default and then removed.
---
--- This documentation is generated with the enabled __json__ flag and functions
--- described here support JSON and are deprecated. JSON instances are provided
--- now by an additional package, __graphql-spice__. To start using the new
--- package create __cabal.project__ in the root directory of your project with
--- the following contents:
---
--- @
--- packages: .
--- constraints: graphql -json
--- @
---
--- Then add __graphql-spice__ as dependency.
---
--- The new version of this module defines only one function, @graphql@, which
--- works with the internal GraphQL value representation used by this lbirary.
--- Refer to @Language.GraphQL.JSON.graphql@ in __graphql-spice__ for the
--- function that accepts and returns JSON.
 module Language.GraphQL
     ( graphql
-    , graphqlSubs
     ) where
 
 import Control.Monad.Catch (MonadCatch)
-import qualified Data.Aeson as Aeson
-import qualified Data.Aeson.Types as Aeson
-import qualified Data.HashMap.Strict as HashMap
-import Data.Maybe (catMaybes)
-import qualified Data.Sequence as Seq
-import Data.Text (Text)
-import Language.GraphQL.AST
-import Language.GraphQL.Error
-import Language.GraphQL.Execute
-import qualified Language.GraphQL.Validate as Validate
-import Language.GraphQL.Type.Schema (Schema)
-import Text.Megaparsec (parse)
-
-{-# DEPRECATED graphql "Use graphql-spice package instead" #-}
--- | If the text parses correctly as a @GraphQL@ query the query is
--- executed using the given 'Schema'.
-graphql :: MonadCatch m
-    => Schema m -- ^ Resolvers.
-    -> Text -- ^ Text representing a @GraphQL@ request document.
-    -> m (Either (ResponseEventStream m Aeson.Value) Aeson.Object) -- ^ Response.
-graphql schema = graphqlSubs schema mempty mempty
-
-{-# DEPRECATED graphqlSubs "Use graphql-spice package instead" #-}
--- | If the text parses correctly as a @GraphQL@ query the substitution is
--- applied to the query and the query is then executed using to the given
--- 'Schema'.
-graphqlSubs :: MonadCatch m
-    => Schema m -- ^ Resolvers.
-    -> Maybe Text -- ^ Operation name.
-    -> Aeson.Object -- ^ Variable substitution function.
-    -> Text -- ^ Text representing a @GraphQL@ request document.
-    -> m (Either (ResponseEventStream m Aeson.Value) Aeson.Object) -- ^ Response.
-graphqlSubs schema operationName variableValues document' =
-    case parse document "" document' of
-        Left errorBundle -> pure . formatResponse <$> parseError errorBundle
-        Right parsed ->
-            case validate parsed of
-                Seq.Empty -> fmap formatResponse
-                    <$> execute schema operationName variableValues parsed
-                errors -> pure $ pure
-                    $ HashMap.singleton "errors"
-                    $ Aeson.toJSON
-                    $ fromValidationError <$> errors
-  where
-    validate = Validate.document schema Validate.specifiedRules
-    formatResponse (Response data'' Seq.Empty) = HashMap.singleton "data" data''
-    formatResponse (Response data'' errors') = HashMap.fromList
-        [ ("data", data'')
-        , ("errors", Aeson.toJSON $ fromError <$> errors')
-        ]
-    fromError Error{..} = Aeson.object $ catMaybes
-        [ Just ("message", Aeson.toJSON message)
-        , toMaybe fromLocation "locations" locations
-        , toMaybe fromPath "path" path
-        ]
-    fromValidationError Validate.Error{..} = Aeson.object
-        [ ("message", Aeson.toJSON message)
-        , ("locations", Aeson.listValue fromLocation locations)
-        ]
-    toMaybe _ _ [] = Nothing
-    toMaybe f key xs = Just (key, Aeson.listValue f xs)
-    fromPath (Segment segment) = Aeson.String segment
-    fromPath (Index index) = Aeson.toJSON index
-    fromLocation Location{..} = Aeson.object
-        [ ("line", Aeson.toJSON line)
-        , ("column", Aeson.toJSON column)
-        ]
-#else
--- | This module provides the functions to parse and execute @GraphQL@ queries.
-module Language.GraphQL
-    ( graphql
-    ) where
-
-import Control.Monad.Catch (MonadCatch)
 import Data.HashMap.Strict (HashMap)
 import qualified Data.Sequence as Seq
 import Data.Text (Text)
@@ -144,4 +44,3 @@
         , locations = locations
         , path = []
         }
-#endif
diff --git a/src/Language/GraphQL/AST/Document.hs b/src/Language/GraphQL/AST/Document.hs
--- a/src/Language/GraphQL/AST/Document.hs
+++ b/src/Language/GraphQL/AST/Document.hs
@@ -464,6 +464,14 @@
 newtype Description = Description (Maybe Text)
     deriving (Eq, Show)
 
+instance Semigroup Description
+  where
+    Description lhs <> Description rhs = Description $ lhs <> rhs
+
+instance Monoid Description
+  where
+    mempty = Description mempty
+
 -- ** Types
 
 -- | Type definitions describe various user-defined types.
diff --git a/src/Language/GraphQL/AST/Encoder.hs b/src/Language/GraphQL/AST/Encoder.hs
--- a/src/Language/GraphQL/AST/Encoder.hs
+++ b/src/Language/GraphQL/AST/Encoder.hs
@@ -14,10 +14,11 @@
     , operationType
     , pretty
     , type'
+    , typeSystemDefinition
     , value
     ) where
 
-import Data.Foldable (fold)
+import Data.Foldable (fold, Foldable (..))
 import qualified Data.List.NonEmpty as NonEmpty
 import Data.Text (Text)
 import qualified Data.Text as Text
@@ -28,6 +29,7 @@
 import Data.Text.Lazy.Builder.Int (decimal)
 import Data.Text.Lazy.Builder.RealFloat (realFloat)
 import qualified Language.GraphQL.AST.Document as Full
+import qualified Language.GraphQL.AST.DirectiveLocation as DirectiveLocation
 
 -- | Instructs the encoder whether the GraphQL document should be minified or
 --   pretty printed.
@@ -54,8 +56,247 @@
     encodeDocument = foldr executableDefinition [] defs
     executableDefinition (Full.ExecutableDefinition executableDefinition') acc =
         definition formatter executableDefinition' : acc
-    executableDefinition _ acc = acc
+    executableDefinition (Full.TypeSystemDefinition typeSystemDefinition' _location) acc =
+        typeSystemDefinition formatter typeSystemDefinition' : acc
+    executableDefinition (Full.TypeSystemExtension typeSystemExtension' _location) acc =
+        typeSystemExtension formatter typeSystemExtension' : acc
 
+directiveLocation :: DirectiveLocation.DirectiveLocation -> Lazy.Text
+directiveLocation = Lazy.Text.pack . show
+
+withLineBreak :: Formatter -> Lazy.Text.Text -> Lazy.Text.Text
+withLineBreak formatter encodeDefinition
+    | Pretty _ <- formatter = Lazy.Text.snoc encodeDefinition '\n'
+    | Minified <- formatter = encodeDefinition
+
+typeSystemExtension :: Formatter -> Full.TypeSystemExtension -> Lazy.Text
+typeSystemExtension formatter = \case
+    Full.SchemaExtension schemaExtension' ->
+        schemaExtension formatter schemaExtension'
+    Full.TypeExtension typeExtension' -> typeExtension formatter typeExtension'
+
+schemaExtension :: Formatter -> Full.SchemaExtension -> Lazy.Text
+schemaExtension formatter = \case
+    Full.SchemaOperationExtension operationDirectives operationTypeDefinitions' ->
+        withLineBreak formatter
+            $ "extend schema "
+            <> optempty (directives formatter) operationDirectives
+            <> bracesList formatter (operationTypeDefinition formatter) (NonEmpty.toList operationTypeDefinitions')
+    Full.SchemaDirectivesExtension operationDirectives -> "extend schema "
+        <> optempty (directives formatter) (NonEmpty.toList operationDirectives)
+
+typeExtension :: Formatter -> Full.TypeExtension -> Lazy.Text
+typeExtension formatter = \case
+    Full.ScalarTypeExtension name' directives'
+        -> "extend scalar "
+        <> Lazy.Text.fromStrict name'
+        <> directives formatter (NonEmpty.toList directives')
+    Full.ObjectTypeFieldsDefinitionExtension name' ifaces' directives' fields'
+        -> "extend type "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (" " <>) (implementsInterfaces ifaces')
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (fieldDefinition nextFormatter) (NonEmpty.toList fields')
+    Full.ObjectTypeDirectivesExtension name' ifaces' directives'
+        -> "extend type "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (" " <>) (implementsInterfaces ifaces')
+        <> optempty (directives formatter) (NonEmpty.toList directives')
+    Full.ObjectTypeImplementsInterfacesExtension name' ifaces'
+        -> "extend type "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (" " <>) (implementsInterfaces ifaces')
+    Full.InterfaceTypeFieldsDefinitionExtension name' directives' fields'
+        -> "extend interface "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (fieldDefinition nextFormatter) (NonEmpty.toList fields')
+    Full.InterfaceTypeDirectivesExtension name' directives'
+        -> "extend interface "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) (NonEmpty.toList directives')
+    Full.UnionTypeUnionMemberTypesExtension name' directives' members'
+        -> "extend union "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> unionMemberTypes formatter members'
+    Full.UnionTypeDirectivesExtension name' directives'
+        -> "extend union "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) (NonEmpty.toList directives')
+    Full.EnumTypeEnumValuesDefinitionExtension name' directives' members'
+        -> "extend enum "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (enumValueDefinition formatter) (NonEmpty.toList members')
+    Full.EnumTypeDirectivesExtension name' directives'
+        -> "extend enum "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) (NonEmpty.toList directives')
+    Full.InputObjectTypeInputFieldsDefinitionExtension name' directives' fields'
+        -> "extend input "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (inputValueDefinition nextFormatter) (NonEmpty.toList fields')
+    Full.InputObjectTypeDirectivesExtension name' directives'
+        -> "extend input "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) (NonEmpty.toList directives')
+  where
+    nextFormatter = incrementIndent formatter
+
+-- | Converts a t'Full.TypeSystemDefinition' into a string.
+typeSystemDefinition :: Formatter -> Full.TypeSystemDefinition -> Lazy.Text
+typeSystemDefinition formatter = \case
+    Full.SchemaDefinition operationDirectives operationTypeDefinitions' ->
+        withLineBreak formatter
+            $ "schema "
+            <> optempty (directives formatter) operationDirectives
+            <> bracesList formatter (operationTypeDefinition formatter) (NonEmpty.toList operationTypeDefinitions')
+    Full.TypeDefinition typeDefinition' -> typeDefinition formatter typeDefinition'
+    Full.DirectiveDefinition description' name' arguments' locations
+        -> description formatter description'
+        <> "@"
+        <> Lazy.Text.fromStrict name'
+        <> argumentsDefinition formatter arguments'
+        <> " on"
+        <> pipeList formatter (directiveLocation <$> locations)
+
+operationTypeDefinition :: Formatter -> Full.OperationTypeDefinition -> Lazy.Text.Text
+operationTypeDefinition formatter (Full.OperationTypeDefinition operationType' namedType')
+    = indentLine (incrementIndent formatter)
+    <> operationType formatter operationType'
+    <> colon formatter
+    <> Lazy.Text.fromStrict namedType'
+
+fieldDefinition :: Formatter -> Full.FieldDefinition -> Lazy.Text.Text
+fieldDefinition formatter fieldDefinition' =
+    let Full.FieldDefinition description' name' arguments' type'' directives' = fieldDefinition'
+     in optempty (description formatter) description'
+            <> indentLine formatter
+            <> Lazy.Text.fromStrict name'
+            <> argumentsDefinition formatter arguments'
+            <> colon formatter
+            <> type' type''
+            <> optempty (directives formatter) directives'
+
+argumentsDefinition :: Formatter -> Full.ArgumentsDefinition -> Lazy.Text.Text
+argumentsDefinition formatter (Full.ArgumentsDefinition arguments') =
+    parensCommas formatter (argumentDefinition formatter) arguments'
+
+argumentDefinition :: Formatter -> Full.InputValueDefinition -> Lazy.Text.Text
+argumentDefinition formatter definition' =
+    let Full.InputValueDefinition description' name' type'' defaultValue' directives' = definition'
+     in optempty (description formatter) description'
+            <> Lazy.Text.fromStrict name'
+            <> colon formatter
+            <> type' type''
+            <> maybe mempty (defaultValue formatter . Full.node) defaultValue'
+            <> directives formatter directives'
+
+inputValueDefinition :: Formatter -> Full.InputValueDefinition -> Lazy.Text.Text
+inputValueDefinition formatter definition' =
+    let Full.InputValueDefinition description' name' type'' defaultValue' directives' = definition'
+     in optempty (description formatter) description'
+            <> indentLine formatter
+            <> Lazy.Text.fromStrict name'
+            <> colon formatter
+            <> type' type''
+            <> maybe mempty (defaultValue formatter . Full.node) defaultValue'
+            <> directives formatter directives'
+
+typeDefinition :: Formatter -> Full.TypeDefinition -> Lazy.Text
+typeDefinition formatter = \case
+    Full.ScalarTypeDefinition description' name' directives'
+        -> optempty (description formatter) description'
+        <> "scalar "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+    Full.ObjectTypeDefinition description' name' ifaces' directives' fields'
+        -> optempty (description formatter) description'
+        <> "type "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (" " <>) (implementsInterfaces ifaces')
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (fieldDefinition nextFormatter) fields'
+    Full.InterfaceTypeDefinition description' name' directives' fields'
+        -> optempty (description formatter) description'
+        <> "interface "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (fieldDefinition nextFormatter) fields'
+    Full.UnionTypeDefinition description' name' directives' members'
+        -> optempty (description formatter) description'
+        <> "union "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> unionMemberTypes formatter members'
+    Full.EnumTypeDefinition description' name' directives' members'
+        -> optempty (description formatter) description'
+        <> "enum "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (enumValueDefinition formatter) members'
+    Full.InputObjectTypeDefinition description' name' directives' fields'
+        -> optempty (description formatter) description'
+        <> "input "
+        <> Lazy.Text.fromStrict name'
+        <> optempty (directives formatter) directives'
+        <> eitherFormat formatter " " ""
+        <> bracesList formatter (inputValueDefinition nextFormatter) fields'
+  where
+    nextFormatter = incrementIndent formatter
+
+implementsInterfaces :: Foldable t => Full.ImplementsInterfaces t -> Lazy.Text
+implementsInterfaces (Full.ImplementsInterfaces interfaces)
+    | null interfaces = mempty
+    | otherwise = Lazy.Text.fromStrict
+        $ Text.append "implements "
+        $ Text.intercalate " & "
+        $ toList interfaces
+
+unionMemberTypes :: Foldable t => Formatter -> Full.UnionMemberTypes t -> Lazy.Text
+unionMemberTypes formatter (Full.UnionMemberTypes memberTypes)
+    | null memberTypes = mempty
+    | otherwise = Lazy.Text.append "="
+        $ pipeList formatter
+        $ Lazy.Text.fromStrict
+        <$> toList memberTypes
+
+pipeList :: Foldable t => Formatter -> t Lazy.Text -> Lazy.Text
+pipeList Minified =  (" " <>) . Lazy.Text.intercalate " | " . toList
+pipeList (Pretty _) =  Lazy.Text.concat
+    . fmap (("\n" <> indentSymbol <> "| ") <>)
+    . toList 
+
+enumValueDefinition :: Formatter -> Full.EnumValueDefinition -> Lazy.Text
+enumValueDefinition (Pretty _) enumValue =
+    let Full.EnumValueDefinition description' name' directives' = enumValue
+        formatter = Pretty 1
+     in description formatter description'
+        <> indentLine formatter
+        <> Lazy.Text.fromStrict name'
+        <> directives formatter directives'
+enumValueDefinition Minified enumValue =
+    let Full.EnumValueDefinition description' name' directives' = enumValue
+     in description Minified description'
+        <> Lazy.Text.fromStrict name'
+        <> directives Minified directives'
+
+description :: Formatter -> Full.Description -> Lazy.Text.Text
+description _formatter (Full.Description Nothing) = ""
+description formatter (Full.Description (Just description')) =
+    stringValue formatter description'
+
 -- | Converts a t'Full.ExecutableDefinition' into a string.
 definition :: Formatter -> Full.ExecutableDefinition -> Lazy.Text
 definition formatter x
@@ -100,7 +341,7 @@
     let Full.VariableDefinition variableName variableType defaultValue' _ =
             variableDefinition'
      in variable variableName
-    <> eitherFormat formatter ": " ":"
+    <> colon formatter
     <> type' variableType
     <> maybe mempty (defaultValue formatter . Full.node) defaultValue'
 
@@ -127,21 +368,27 @@
 indent indentation = Lazy.Text.replicate (fromIntegral indentation) indentSymbol
 
 selection :: Formatter -> Full.Selection -> Lazy.Text
-selection formatter = Lazy.Text.append indent' . encodeSelection
+selection formatter = Lazy.Text.append (indentLine formatter')
+    . encodeSelection
   where
     encodeSelection (Full.FieldSelection fieldSelection) =
-        field incrementIndent fieldSelection
+        field formatter' fieldSelection
     encodeSelection (Full.InlineFragmentSelection fragmentSelection) =
-        inlineFragment incrementIndent fragmentSelection
+        inlineFragment formatter' fragmentSelection
     encodeSelection (Full.FragmentSpreadSelection fragmentSelection) =
-        fragmentSpread incrementIndent fragmentSelection
-    incrementIndent
-        | Pretty indentation <- formatter = Pretty $ indentation + 1
-        | otherwise = Minified
-    indent'
-        | Pretty indentation <- formatter = indent $ indentation + 1
-        | otherwise = ""
+        fragmentSpread formatter' fragmentSelection
+    formatter' = incrementIndent formatter
 
+indentLine :: Formatter -> Lazy.Text
+indentLine formatter
+    | Pretty indentation <- formatter = indent indentation
+    | otherwise = ""
+
+incrementIndent :: Formatter -> Formatter
+incrementIndent formatter
+    | Pretty indentation <- formatter = Pretty $ indentation + 1
+    | otherwise = Minified
+
 colon :: Formatter -> Lazy.Text
 colon formatter = eitherFormat formatter ": " ":"
 
@@ -198,8 +445,10 @@
     = "@" <> Lazy.Text.fromStrict name <> optempty (arguments formatter) args
 
 directives :: Formatter -> [Full.Directive] -> Lazy.Text
-directives Minified = spaces (directive Minified)
-directives formatter = Lazy.Text.cons ' ' . spaces (directive formatter)
+directives Minified values = spaces (directive Minified) values
+directives formatter values
+    | null values = ""
+    | otherwise = Lazy.Text.cons ' ' $ spaces (directive formatter) values
 
 -- | Converts a 'Full.Value' into a string.
 value :: Formatter -> Full.Value -> Lazy.Text
diff --git a/src/Language/GraphQL/Execute.hs b/src/Language/GraphQL/Execute.hs
--- a/src/Language/GraphQL/Execute.hs
+++ b/src/Language/GraphQL/Execute.hs
@@ -39,6 +39,7 @@
 import Data.Maybe (fromMaybe)
 import Data.Sequence (Seq)
 import qualified Data.Sequence as Seq
+import qualified Data.Vector as Vector
 import Data.Text (Text)
 import qualified Data.Text as Text
 import Data.Typeable (cast)
@@ -466,12 +467,12 @@
 completeValue (Out.isNonNullType -> False) _ _ Type.Null =
     pure null
 completeValue outputType@(Out.ListBaseType listType) fields errorPath (Type.List list)
-    = foldM go (0, []) list >>= coerceResult outputType . List . snd
+    = foldM go Vector.empty list >>= coerceResult outputType . List . Vector.toList
   where
-    go (index, accumulator) listItem = do
-        let updatedPath = Index index : errorPath
-        completedValue <- completeValue listType fields updatedPath listItem
-        pure (index + 1, completedValue : accumulator)
+    go accumulator listItem =
+        let updatedPath = Index (Vector.length accumulator) : errorPath
+         in Vector.snoc accumulator
+            <$> completeValue listType fields updatedPath listItem
 completeValue outputType@(Out.ScalarBaseType _) _ _ (Type.Int int) =
     coerceResult outputType $ Int int
 completeValue outputType@(Out.ScalarBaseType _) _ _ (Type.Boolean boolean) =
diff --git a/src/Language/GraphQL/Execute/Coerce.hs b/src/Language/GraphQL/Execute/Coerce.hs
--- a/src/Language/GraphQL/Execute/Coerce.hs
+++ b/src/Language/GraphQL/Execute/Coerce.hs
@@ -5,14 +5,8 @@
 {-# LANGUAGE ExplicitForAll #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ViewPatterns #-}
-{-# LANGUAGE CPP #-}
 
 -- | Types and functions used for input and result coercion.
---
--- JSON instances in this module are only available with the __json__
--- flag that is currently on by default, but will be disabled in the future.
--- Refer to the documentation in the 'Language.GraphQL' module and to
--- the __graphql-spice__ package.
 module Language.GraphQL.Execute.Coerce
     ( Output(..)
     , Serialize(..)
@@ -21,10 +15,6 @@
     , matchFieldValues
     ) where
 
-#ifdef WITH_JSON
-import qualified Data.Aeson as Aeson
-import Data.Scientific (toBoundedInteger, toRealFloat)
-#endif
 import Data.Int (Int32)
 import Data.HashMap.Strict (HashMap)
 import qualified Data.HashMap.Strict as HashMap
@@ -232,69 +222,3 @@
         $ HashMap.fromList
         $ OrderedMap.toList object
     serialize _ _ = Nothing
-
-#ifdef WITH_JSON
-instance Serialize Aeson.Value where
-    serialize (Out.ScalarBaseType scalarType) value
-        | Type.ScalarType "Int" _ <- scalarType
-        , Int int <- value = Just $ Aeson.toJSON int
-        | Type.ScalarType "Float" _ <- scalarType
-        , Float float <- value = Just $ Aeson.toJSON float
-        | Type.ScalarType "String" _ <- scalarType
-        , String string <- value = Just $ Aeson.String string
-        | Type.ScalarType "ID" _ <- scalarType
-        , String string <- value = Just $ Aeson.String string
-        | Type.ScalarType "Boolean" _ <- scalarType
-        , Boolean boolean <- value = Just $ Aeson.Bool boolean
-    serialize _ (Enum enum) = Just $ Aeson.String enum
-    serialize _ (List list) = Just $ Aeson.toJSON list
-    serialize _ (Object object) = Just
-        $ Aeson.object
-        $ OrderedMap.toList
-        $ Aeson.toJSON <$> object
-    serialize _ _ = Nothing
-    null = Aeson.Null
-
-instance VariableValue Aeson.Value where
-    coerceVariableValue _ Aeson.Null = Just Type.Null
-    coerceVariableValue (In.ScalarBaseType scalarType) value
-        | (Aeson.String stringValue) <- value = Just $ Type.String stringValue
-        | (Aeson.Bool booleanValue) <- value = Just $ Type.Boolean booleanValue
-        | (Aeson.Number numberValue) <- value
-        , (Type.ScalarType "Float" _) <- scalarType =
-            Just $ Type.Float $ toRealFloat numberValue
-        | (Aeson.Number numberValue) <- value = -- ID or Int
-            Type.Int <$> toBoundedInteger numberValue
-    coerceVariableValue (In.EnumBaseType _) (Aeson.String stringValue) =
-        Just $ Type.Enum stringValue
-    coerceVariableValue (In.InputObjectBaseType objectType) value
-        | (Aeson.Object objectValue) <- value = do
-            let (In.InputObjectType _ _ inputFields) = objectType
-            (newObjectValue, resultMap) <- foldWithKey objectValue inputFields
-            if HashMap.null newObjectValue
-                then Just $ Type.Object resultMap
-                else Nothing
-      where
-        foldWithKey objectValue = HashMap.foldrWithKey matchFieldValues'
-            $ Just (objectValue, HashMap.empty)
-        matchFieldValues' _ _ Nothing = Nothing
-        matchFieldValues' fieldName inputField (Just (objectValue, resultMap)) =
-            let (In.InputField _ fieldType _) = inputField
-                insert = flip (HashMap.insert fieldName) resultMap
-                newObjectValue = HashMap.delete fieldName objectValue
-             in case HashMap.lookup fieldName objectValue of
-                    Just variableValue -> do
-                        coerced <- coerceVariableValue fieldType variableValue
-                        pure (newObjectValue, insert coerced)
-                    Nothing -> Just (objectValue, resultMap)
-    coerceVariableValue (In.ListBaseType listType) value
-        | (Aeson.Array arrayValue) <- value =
-            Type.List <$> foldr foldVector (Just []) arrayValue
-        | otherwise = coerceVariableValue listType value
-      where
-        foldVector _ Nothing = Nothing
-        foldVector variableValue (Just list) = do
-            coerced <- coerceVariableValue listType variableValue
-            pure $ coerced : list 
-    coerceVariableValue _ _ = Nothing
-#endif
diff --git a/src/Test/Hspec/GraphQL.hs b/src/Test/Hspec/GraphQL.hs
deleted file mode 100644
--- a/src/Test/Hspec/GraphQL.hs
+++ /dev/null
@@ -1,49 +0,0 @@
-{- This Source Code Form is subject to the terms of the Mozilla Public License,
-   v. 2.0. If a copy of the MPL was not distributed with this file, You can
-   obtain one at https://mozilla.org/MPL/2.0/. -}
-
-{-# LANGUAGE CPP #-}
-
-#ifdef WITH_JSON
-{-# LANGUAGE ExplicitForAll #-}
-{-# LANGUAGE OverloadedStrings #-}
-
--- | Test helpers.
-module Test.Hspec.GraphQL {-# DEPRECATED "Use graphql-spice package instead" #-}
-    ( shouldResolve
-    , shouldResolveTo
-    ) where
-
-import Control.Monad.Catch (MonadCatch)
-import qualified Data.Aeson as Aeson
-import qualified Data.HashMap.Strict as HashMap
-import Data.Text (Text)
-import Language.GraphQL.Error
-import Test.Hspec.Expectations (Expectation, expectationFailure, shouldBe, shouldNotSatisfy)
-
--- | Asserts that a query resolves to some value.
-shouldResolveTo :: MonadCatch m
-    => Either (ResponseEventStream m Aeson.Value) Aeson.Object
-    -> Aeson.Object
-    -> Expectation
-shouldResolveTo (Right actual) expected = actual `shouldBe` expected
-shouldResolveTo _ _ = expectationFailure
-    "the query is expected to resolve to a value, but it resolved to an event stream"
-
--- | Asserts that the response doesn't contain any errors.
-shouldResolve :: MonadCatch m
-    => (Text -> IO (Either (ResponseEventStream m Aeson.Value) Aeson.Object))
-    -> Text
-    -> Expectation
-shouldResolve executor query = do
-    actual <- executor query
-    case actual of
-        Right response ->
-            response `shouldNotSatisfy` HashMap.member "errors"
-        _ -> expectationFailure
-            "the query is expected to resolve to a value, but it resolved to an event stream"
-#else
-module Test.Hspec.GraphQL {-# DEPRECATED "Use graphql-spice package instead" #-}
-    (
-    ) where
-#endif
diff --git a/tests/Language/GraphQL/AST/DocumentSpec.hs b/tests/Language/GraphQL/AST/DocumentSpec.hs
--- a/tests/Language/GraphQL/AST/DocumentSpec.hs
+++ b/tests/Language/GraphQL/AST/DocumentSpec.hs
@@ -18,3 +18,9 @@
                     ]
                 expected = "{ field1: 1.2, field2: null }"
              in show object `shouldBe` expected
+
+    describe "Description" $
+        it "keeps content when merging with no description" $
+            let expected = Description $ Just "Left description"
+                actual = expected <> Description Nothing
+             in actual `shouldBe` expected
diff --git a/tests/Language/GraphQL/AST/EncoderSpec.hs b/tests/Language/GraphQL/AST/EncoderSpec.hs
--- a/tests/Language/GraphQL/AST/EncoderSpec.hs
+++ b/tests/Language/GraphQL/AST/EncoderSpec.hs
@@ -4,6 +4,7 @@
     ( spec
     ) where
 
+import Data.List.NonEmpty (NonEmpty(..))
 import qualified Language.GraphQL.AST.Document as Full
 import Language.GraphQL.AST.Encoder
 import Language.GraphQL.TH
@@ -178,3 +179,91 @@
         it "produces lowercase mutation operation type" $
             let actual = operationType pretty Full.Mutation
              in actual `shouldBe` "mutation"
+
+    describe "typeSystemDefinition" $ do
+        it "produces a schema with an indented operation type definition" $
+            let queryType = Full.OperationTypeDefinition Full.Query "QueryRootType"
+                mutationType = Full.OperationTypeDefinition Full.Mutation "MutationType"
+                operations = queryType :| pure mutationType
+                definition' = Full.SchemaDefinition [] operations
+                expected = Text.Lazy.snoc [gql|
+                  schema {
+                    query: QueryRootType
+                    mutation: MutationType
+                  }
+                |] '\n'
+                actual = typeSystemDefinition pretty definition'
+             in actual `shouldBe` expected
+
+        it "encodes a scalar type definition" $
+            let uuidType = Full.ScalarTypeDefinition mempty "UUID" mempty
+                definition' = Full.TypeDefinition uuidType
+                expected = "scalar UUID"
+                actual = typeSystemDefinition pretty definition'
+             in actual `shouldBe` expected
+
+        it "encodes an interface definition" $
+            let someType = Full.TypeNamed "String"
+                argument = Full.InputValueDefinition mempty "arg" someType Nothing mempty
+                arguments = Full.ArgumentsDefinition [argument]
+                definition' = Full.TypeDefinition
+                    $ Full.InterfaceTypeDefinition mempty "UUID" mempty
+                    $ pure
+                    $ Full.FieldDefinition mempty "value" arguments someType mempty
+                expected = [gql|
+                  interface UUID {
+                    value(arg: String): String
+                  }
+                |]
+                actual = typeSystemDefinition pretty definition'
+             in actual `shouldBe` expected
+
+        it "encodes an union definition" $
+            let definition' = Full.TypeDefinition
+                    $ Full.UnionTypeDefinition mempty "SearchResult" mempty
+                    $ Full.UnionMemberTypes ["Photo", "Person"]
+                expected = [gql|
+                  union SearchResult =
+                    | Photo
+                    | Person
+                |]
+                actual = typeSystemDefinition pretty definition'
+             in actual `shouldBe` expected
+
+        it "encodes an enum definition" $
+            let values =
+                    [ Full.EnumValueDefinition mempty "NORTH" mempty
+                    , Full.EnumValueDefinition mempty "EAST" mempty
+                    , Full.EnumValueDefinition mempty "SOUTH" mempty
+                    , Full.EnumValueDefinition mempty "WEST" mempty
+                    ]
+                definition' = Full.TypeDefinition
+                    $ Full.EnumTypeDefinition mempty "Direction" mempty values
+                expected = [gql|
+                  enum Direction {
+                    NORTH
+                    EAST
+                    SOUTH
+                    WEST
+                  }
+                |]
+                actual = typeSystemDefinition pretty definition'
+             in actual `shouldBe` expected
+
+        it "encodes an input type" $
+            let intType = Full.TypeNonNull $ Full.NonNullTypeNamed "Int"
+                stringType = Full.TypeNamed "String"
+                fields =
+                    [ Full.InputValueDefinition mempty "a" stringType Nothing mempty
+                    , Full.InputValueDefinition mempty "b" intType Nothing mempty
+                    ]
+                definition' = Full.TypeDefinition
+                    $ Full.InputObjectTypeDefinition mempty "ExampleInputObject" mempty fields
+                expected = [gql|
+                  input ExampleInputObject {
+                    a: String
+                    b: Int!
+                  }
+                |]
+                actual = typeSystemDefinition pretty definition'
+             in actual `shouldBe` expected
diff --git a/tests/Language/GraphQL/ExecuteSpec.hs b/tests/Language/GraphQL/ExecuteSpec.hs
--- a/tests/Language/GraphQL/ExecuteSpec.hs
+++ b/tests/Language/GraphQL/ExecuteSpec.hs
@@ -66,8 +66,9 @@
 queryType = Out.ObjectType "Query" Nothing []
     $ HashMap.fromList
     [ ("philosopher", ValueResolver philosopherField philosopherResolver)
-    , ("genres", ValueResolver genresField genresResolver)
+    , ("throwing", ValueResolver throwingField throwingResolver)
     , ("count", ValueResolver countField countResolver)
+    , ("sequence", ValueResolver sequenceField sequenceResolver)
     ]
   where
     philosopherField =
@@ -75,16 +76,23 @@
         $ HashMap.singleton "id"
         $ In.Argument Nothing (In.NamedScalarType id) Nothing
     philosopherResolver = pure $ Object mempty
-    genresField =
+    throwingField =
         let fieldType = Out.ListType $ Out.NonNullScalarType string
          in Out.Field Nothing fieldType HashMap.empty
-    genresResolver :: Resolve IO
-    genresResolver = throwM PhilosopherException
+    throwingResolver :: Resolve IO
+    throwingResolver = throwM PhilosopherException
     countField =
         let fieldType = Out.NonNullScalarType int
          in Out.Field Nothing fieldType HashMap.empty
     countResolver = pure ""
+    sequenceField =
+        let fieldType = Out.ListType $ Out.NonNullScalarType int
+         in Out.Field Nothing fieldType HashMap.empty
+    sequenceResolver = pure intSequence
 
+intSequence :: Value
+intSequence = Type.List [Type.Int 1, Type.Int 2, Type.Int 3]
+
 musicType :: Out.ObjectType IO
 musicType = Out.ObjectType "Music" Nothing []
     $ HashMap.fromList resolvers
@@ -344,14 +352,14 @@
                 in sourceQuery `shouldResolveTo` expected
 
             it "gives location information for failed result coercion" $
-                let data'' = Object $ HashMap.singleton "genres" Null
+                let data'' = Object $ HashMap.singleton "throwing" Null
                     executionErrors = pure $ Error
                         { message = "PhilosopherException"
                         , locations = [Location 1 3]
-                        , path = [Segment "genres"]
+                        , path = [Segment "throwing"]
                         }
                     expected = Response data'' executionErrors
-                    sourceQuery = "{ genres }"
+                    sourceQuery = "{ throwing }"
                 in sourceQuery `shouldResolveTo` expected
 
             it "sets data to null if a root field isn't nullable" $
@@ -373,6 +381,12 @@
                         }
                     expected = Response data'' executionErrors
                     sourceQuery = "{ philosopher(id: \"1\") { firstLanguage } }"
+                in sourceQuery `shouldResolveTo` expected
+
+            it "returns list elements in the original order" $
+                let data'' = Object $ HashMap.singleton "sequence" intSequence
+                    expected = Response data'' mempty
+                    sourceQuery = "{ sequence }"
                 in sourceQuery `shouldResolveTo` expected
 
             context "queryError" $ do