HsQuasiQuoteTy {} -> acc -- Quasi quotes mention no type variables
HsSpliceTy {} -> acc -- Type splices mention no type variables
HsKindSig ty _ -> extract_lty ty acc
HsQuasiQuoteTy {} -> acc -- Quasi quotes mention no type variables
HsSpliceTy {} -> acc -- Type splices mention no type variables
HsKindSig ty _ -> extract_lty ty acc