= do { arg_tys <- boxySplitTyConApp (tupleTyCon boxity (length pats)) pat_ty
; (pats', pats_tvs, res) <- tc_lpats pstate pats arg_tys thing_inside
= do { arg_tys <- boxySplitTyConApp (tupleTyCon boxity (length pats)) pat_ty
; (pats', pats_tvs, res) <- tc_lpats pstate pats arg_tys thing_inside