DeriveAnyClass and GND don't work well together

I think we definitely have a bug here, but I'm not sure what it really is.

Here's the program:

newtype MyMaybe a = MyMaybe (Maybe a)
  deriving (Functor, Show)

main = print $ MyMaybe $ Just (10 :: Int)

I'm using GHC 7.10.1.

➜  deriveany_bug  ghc --make -fforce-recomp Test.hs -XDeriveAnyClass -XGeneralizedNewtypeDeriving
[1 of 1] Compiling Main             ( Test.hs, Test.o )

Test.hs:2:13:
    Can't make a derived instance of ‘Functor MyMaybe’
      (even with cunning newtype deriving):
      You need DeriveFunctor to derive an instance for this class
      Try GeneralizedNewtypeDeriving for GHC's newtype-deriving extension
    In the newtype declaration for ‘MyMaybe’

Just to try, changing argument order:

➜  deriveany_bug  ghc --make -fforce-recomp Test.hs -XGeneralizedNewtypeDeriving -XDeriveAnyClass
[1 of 1] Compiling Main             ( Test.hs, Test.o )

Test.hs:2:13:
    Can't make a derived instance of ‘Functor MyMaybe’
      (even with cunning newtype deriving):
      You need DeriveFunctor to derive an instance for this class
      Try GeneralizedNewtypeDeriving for GHC's newtype-deriving extension
    In the newtype declaration for ‘MyMaybe’

It works fine if I remove DeriveAnyClass:

➜  deriveany_bug  ghc --make -fforce-recomp Test.hs -XGeneralizedNewtypeDeriving                 
[1 of 1] Compiling Main             ( Test.hs, Test.o )
Linking Test ...

GHC HEAD is failing in exactly the same way.

User manual is saying this in 7.5.6:

In case you try to derive some class on a newtype, and -XGeneralizedNewtypeDeriving is also on, -XDeriveAnyClass takes precedence.

But then why is it telling me to enable GeneralizedNewtypeDeriving in the error message? Even if I already enabled it?

Also, maybe it could try GND when DeriveAnyClass fails? Because the doc is saying DeriveAnyClass has precedence but doesn't specify what happens if it fails.

EDIT: I'd like to work on this myself if experts here help me figuring the right behavior here.