Incorrect instance of GShowSingle for (f :.: g)

[anka-213]

The left parameter (f) in f :.: g is not a generic representation, but a plain representation. Only the right parameter is a Generic representation. See example here.

The instance

instance (GShowSingle Identity f, GShowSingle p g)
  => GShowSingle p (f :.: g) where
  ...

should instead be

instance (Show1 f, GShowSingle p g)
  => GShowSingle p (f :.: g) where
  ...

similarly to the instance for Rec1 f.

---

A simple example of this would be trying to derive Show1 for a type equivalent to Compose.

newtype MyCompose f g a = MyCompose (f (g a))
  deriving Generic1
  deriving Show1 via Generically1 (MyCompose f g)

gives the error

    * Could not deduce (Generic.Data.Internal.Show.GShowSingle
                          Data.Functor.Identity.Identity f)
        arising from the 'deriving' clause of a data type 
declaration
      from the context: Show1 g

[Lysxia]

whoops. Thanks for catching this!

[Lysxia]

Fixed by 1bd6cfd4c379097d5554253fccc1b31a20fe85e7 Released in 0.6.0.1. Thanks again!