ppr_debug :: Var -> PprStyle -> SDoc
ppr_debug (TyVar {}) sty
  | debugStyle sty = brackets (ptext (sLit "tv"))
ppr_debug :: Var -> PprStyle -> SDoc
ppr_debug (TyVar {}) sty
  | debugStyle sty = brackets (ptext (sLit "tv"))
ppr_debug (TyVar {}) sty
  | debugStyle sty = brackets (ptext (sLit "tv"))