The end of your error message:

>       |
>    63 | pattern Any a <- Some a
>       |                       ^

Appears to have program text (a mono-directional pattern binding) that doesn't correspond to the program text you quote.

Whereas

>    pattern Any :: forall a. a -> Some

>    pattern Any a = Some

Is a implicitly bi-directional pattern binding that will never work. (The free var `a` on LHS does not appear in RHS.)

I'm suspecting the explicit forall is not much to do with it.