Commit 2c6fe5b8 authored by Thomas Miedema's avatar Thomas Miedema
Browse files

Add -fwarn-redundant-constrains to test for #9708

Fixes validate on Travis.

Reviewed by: bgamari

Differential Revision: https://phabricator.haskell.org/D1834
parent edc68b2f
{-# LANGUAGE DataKinds, TypeOperators, TypeFamilies #-}
{-# OPTIONS_GHC -fwarn-redundant-constraints #-}
module TcTypeNatSimple where
import GHC.TypeLits
......@@ -16,5 +17,13 @@ type family SomeFun (n :: Nat)
-- with the change to stop Deriveds from rewriting Deriveds (around Dec. 12, 2014),
-- this failed again
-- 2016-01-23: it just started passing again, when
-- -fwarn-redundant-constraints was removed from the default warning set.
-- Turning the warning back on for this module, ghc reports (and probably has
-- for some time):
-- Redundant constraints: (x <= y, y <= x)
-- In the type signature for:
-- ti7 :: (x <= y, y <= x) => Proxy (SomeFun x) -> Proxy y -> ()
ti7 :: (x <= y, y <= x) => Proxy (SomeFun x) -> Proxy y -> ()
ti7 _ _ = ()
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