= do { (pats', ex_tvs, res) <- tcPats LamPat pats tys thing_inside
; tcCheckExistentialPat pats' ex_tvs tys body_ty
; returnM (pats', res) }
- where
tcCheckExistentialPat :: [LPat TcId] -- Patterns (just for error message)
-> [TcTyVar] -- Existentially quantified tyvars bound by pattern