Fix Generics

Author: phadej

src/Data/Aeson/Types/FromJSON.hs

@@ -79,7 +79,7 @@ module Data.Aeson.Types.FromJSON
 
 import Data.Aeson.Internal.Prelude
 
-import Control.Monad (zipWithM)
+import Control.Monad (zipWithM, guard)
 import Data.Aeson.Internal.Functions (mapKey, mapKeyO)
 import Data.Aeson.Internal.Scientific
 import Data.Aeson.Types.Generic
@@ -1384,15 +1384,15 @@ instance {-# OVERLAPPABLE #-}
 
 instance (Selector s, FromJSON a, Generic a, K1 i a ~ Rep a) =>
          RecordFromJSON' arity (S1 s (K1 i a)) where
-    recordParseJSON' args obj =
-      recordParseJSONImpl (fmap K1 omittedField) gParseJSON args obj
+    recordParseJSON' args@(_ :* _ :* opts :* _) obj =
+      recordParseJSONImpl (fmap K1 $ guard (omitNothingFields opts) >> omittedField) gParseJSON args obj
     {-# INLINE recordParseJSON' #-}
 
 instance {-# OVERLAPPING #-}
          (Selector s, FromJSON a) =>
          RecordFromJSON' arity (S1 s (Rec0 a)) where
-    recordParseJSON' args obj =
-      recordParseJSONImpl (fmap K1 omittedField) gParseJSON args obj
+    recordParseJSON' args@(_ :* _ :* opts :* _) obj =
+      recordParseJSONImpl (fmap K1 $ guard (omitNothingFields opts) >> omittedField) gParseJSON args obj
     {-# INLINE recordParseJSON' #-}
 
 instance (Selector s, GFromJSON arity (Rec1 f), FromJSON1 f) =>