diff --git a/getopt-generics.cabal b/getopt-generics.cabal
--- a/getopt-generics.cabal
+++ b/getopt-generics.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.31.0.
+-- This file has been generated from package.yaml by hpack version 0.31.2.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: a8f8322b2416d58ac189c12c7f304a9e93419217f59a6b53375ab335009c9bc3
+-- hash: 7569f6c1eafe060f3285fa68df5dfe8814e101dc3a65a5b63a5c95e6d274791a
 
 name:           getopt-generics
-version:        0.13.0.3
+version:        0.13.0.4
 synopsis:       Create command line interfaces with ease
 description:    Create command line interfaces with ease
 category:       Console, System
@@ -63,7 +63,7 @@
       base ==4.*
     , base-compat >=0.8
     , base-orphans
-    , generics-sop >=0.1 && <0.5
+    , generics-sop >=0.2.3 && <0.6
     , tagged
   default-language: Haskell2010
 
@@ -117,7 +117,7 @@
     , base-compat >=0.8
     , base-orphans
     , filepath
-    , generics-sop >=0.1 && <0.5
+    , generics-sop >=0.2.3 && <0.6
     , hspec >=2.1.8
     , safe
     , silently
diff --git a/src/WithCli/HasArguments.hs b/src/WithCli/HasArguments.hs
--- a/src/WithCli/HasArguments.hs
+++ b/src/WithCli/HasArguments.hs
@@ -289,27 +289,22 @@
   (GHC.Generic a, GTo a, GDatatypeInfo a, All2 HasArguments (GCode a)) =>
   Modifiers ->
   Result (Parser Unnormalized a)
-genericParser modifiers = fmap (fmap gto) $ case gdatatypeInfo (Proxy :: Proxy a) of
-  ADT _ typeName (constructorInfo :* Nil) ->
-    case constructorInfo of
-      (Record _ fields) ->
-        fmap (fmap (SOP . Z)) (fieldsParser modifiers fields)
-      Constructor{} ->
-        fmap (fmap (SOP . Z)) (noSelectorsParser modifiers shape)
-      Infix{} ->
-        err typeName "infix constructors"
-  ADT _ typeName Nil ->
-    err typeName "empty data types"
-  ADT _ typeName (_ :* _ :* _) ->
-    err typeName "sum types"
-  Newtype _ _ (Record _ fields) ->
-    fmap (fmap (SOP . Z)) (fieldsParser modifiers fields)
-  Newtype _ typeName (Constructor _) ->
-    err typeName "constructors without field labels"
-  where
-    err typeName message = Errors $
-      "getopt-generics doesn't support " ++ message ++
-      " (" ++ typeName ++ ")."
+genericParser modifiers = fmap (fmap gto) $
+  let datatypeInfo = gdatatypeInfo (Proxy :: Proxy a)
+      err :: forall a . String -> Result a
+      err message = Errors $
+        "getopt-generics doesn't support " ++ message ++
+        " (" ++ datatypeName datatypeInfo ++ ")."
+  in case constructorInfo datatypeInfo of
+    firstConstructor :* Nil ->
+      case firstConstructor of
+        Record _ fields ->
+          fmap (fmap (SOP . Z)) (fieldsParser modifiers fields)
+        Constructor{} ->
+          fmap (fmap (SOP . Z)) (noSelectorsParser modifiers shape)
+        Infix{} -> err "infix constructors"
+    Nil -> err "empty data types"
+    _ :* _ :* _ -> err "sum types"
 
 fieldsParser :: All HasArguments xs =>
   Modifiers -> NP FieldInfo xs -> Result (Parser Unnormalized (NP I xs))
@@ -323,6 +318,6 @@
   Modifiers -> Shape xs -> Result (Parser Unnormalized (NP I xs))
 noSelectorsParser modifiers = \ case
   ShapeNil -> return $ emptyParser Nil
-  ShapeCons rest -> 
+  ShapeCons rest ->
     fmap (fmap (\ (a, r) -> a :* r)) $
       combine (fmap (fmap I) $ (argumentsParser modifiers Nothing)) (noSelectorsParser modifiers rest)