Incorrect compilation of type synonyms

[flupe]

Bug reported by @liesnikov.

private variable @0 a : Set

Ap : (p : @0 a → Set) → @0 a → Set
Ap p x = p x
{-# COMPILE AGDA2HS Ap #-}

Expected output:

type Ap p = p

Actual output:

type Ap x = p