Use (a :: *) on phantom type variables for kinder type checking #887

servant/src/Servant/API/Capture.hs

@@ -12,7 +12,7 @@ import           GHC.TypeLits  (Symbol)
 --
 -- >>>            -- GET /books/:isbn
 -- >>> type MyApi = "books" :> Capture "isbn" Text :> Get '[JSON] Book
-data Capture (sym :: Symbol) a
+data Capture (sym :: Symbol) (a :: *)
     deriving (Typeable)
 
 
@@ -23,7 +23,7 @@ data Capture (sym :: Symbol) a
 --
 -- >>>            -- GET /src/*
 -- >>> type MyAPI = "src" :> CaptureAll "segments" Text :> Get '[JSON] SourceFile
-data CaptureAll (sym :: Symbol) a
+data CaptureAll (sym :: Symbol) (a :: *)
     deriving (Typeable)
 
 -- $setup

servant/src/Servant/API/QueryParam.hs

@@ -14,7 +14,7 @@ import           GHC.TypeLits (Symbol)
 --
 -- >>> -- /books?author=<author name>
 -- >>> type MyApi = "books" :> QueryParam "author" Text :> Get '[JSON] [Book]
-data QueryParam (sym :: Symbol) a
+data QueryParam (sym :: Symbol) (a :: *)
     deriving Typeable
 
 -- | Lookup the values associated to the @sym@ query string parameter
@@ -28,7 +28,7 @@ data QueryParam (sym :: Symbol) a
 --
 -- >>> -- /books?authors[]=<author1>&authors[]=<author2>&...
 -- >>> type MyApi = "books" :> QueryParams "authors" Text :> Get '[JSON] [Book]
-data QueryParams (sym :: Symbol) a
+data QueryParams (sym :: Symbol) (a :: *)
     deriving Typeable
 
 -- | Lookup a potentially value-less query string parameter

servant/src/Servant/API/ReqBody.hs

@@ -11,7 +11,7 @@ import           Data.Typeable (Typeable)
 --
 -- >>>            -- POST /books
 -- >>> type MyApi = "books" :> ReqBody '[JSON] Book :> Post '[JSON] Book
-data ReqBody (contentTypes :: [*]) a
+data ReqBody (contentTypes :: [*]) (a :: *)
     deriving (Typeable)
 
 -- $setup

servant/src/Servant/API/Stream.hs

@@ -23,7 +23,7 @@ import           Control.Arrow               (first)
 import           Network.HTTP.Types.Method   (StdMethod (..))
 
 -- | A Stream endpoint for a given method emits a stream of encoded values at a given Content-Type, delimited by a framing strategy. Steam endpoints always return response code 200 on success. Type synonyms are provided for standard methods.
-data Stream (method :: k1) (framing :: *) (contentType :: *) a
+data Stream (method :: k1) (framing :: *) (contentType :: *) (a :: *)
   deriving (Typeable, Generic)
 
 type StreamGet  = Stream 'GET

servant/src/Servant/API/Sub.hs

@@ -14,7 +14,7 @@ import           Data.Typeable (Typeable)
 -- >>> -- GET /hello/world
 -- >>> -- returning a JSON encoded World value
 -- >>> type MyApi = "hello" :> "world" :> Get '[JSON] World
-data (path :: k) :> a
+data (path :: k) :> (a :: *)
     deriving (Typeable)
 infixr 4 :>
 

servant/src/Servant/API/Verbs.hs

@@ -23,7 +23,7 @@ import           Network.HTTP.Types.Method (Method, StdMethod (..),
 -- provided, but you are free to define your own:
 --
 -- >>> type Post204 contentTypes a = Verb 'POST 204 contentTypes a
-data Verb (method :: k1) (statusCode :: Nat) (contentTypes :: [*]) a
+data Verb (method :: k1) (statusCode :: Nat) (contentTypes :: [*]) (a :: *)
   deriving (Typeable, Generic)
 
 -- * 200 responses

servant/test/Servant/Utils/LinksSpec.hs

@@ -24,7 +24,7 @@ type TestApi =
   -- All of the verbs
   :<|> "get" :> Get '[JSON] NoContent
   :<|> "put" :> Put '[JSON] NoContent
-  :<|> "post" :> ReqBody '[JSON] 'True :> Post '[JSON] NoContent
+  :<|> "post" :> ReqBody '[JSON] Bool :> Post '[JSON] NoContent
   :<|> "delete" :> Header "ponies" String :> Delete '[JSON] NoContent
   :<|> "raw" :> Raw
   :<|> NoEndpoint
@@ -124,6 +124,6 @@ type WrongPath = "getTypo" :> Get '[JSON] NoContent
 type WrongReturnType = "get" :> Get '[JSON] Bool
 type WrongContentType = "get" :> Get '[OctetStream] NoContent
 type WrongMethod = "get" :> Post '[JSON] NoContent
-type NotALink = "hello" :> ReqBody '[JSON] 'True :> Get '[JSON] Bool
+type NotALink = "hello" :> ReqBody '[JSON] Bool :> Get '[JSON] Bool
 type AllGood = "get" :> Get '[JSON] NoContent
 type NoEndpoint = "empty" :> EmptyAPI