tcExpr (SectionL arg1 op) res_ty
= do { (op', op_ty) <- tcInferFun op
; dflags <- getDOpts -- Note [Left sections]
- ; let n_reqd_args | dopt Opt_PostfixOperators dflags = 1
+ ; let n_reqd_args | xopt Opt_PostfixOperators dflags = 1
| otherwise = 2
; (co_fn, (arg1_ty:arg_tys), op_res_ty) <- unifyOpFunTys op n_reqd_args op_ty