[commit: ghc] master: Enable warning flags to safe-guard against regressions in `base` (79c4f10)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/79c4f10e4928c37bf4bbad974be0bd693df2d2b9/ghc

>---------------------------------------------------------------

commit 79c4f10e4928c37bf4bbad974be0bd693df2d2b9
Author: Herbert Valerio Riedel <hvr at gnu.org>
Date:   Thu May 3 12:50:25 2018 -0400

    Enable warning flags to safe-guard against regressions in `base`
    
    Test Plan: via CI
    
    Reviewers: bgamari
    
    Subscribers: dfeuer, thomie, carter
    
    Differential Revision: https://phabricator.haskell.org/D4640


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79c4f10e4928c37bf4bbad974be0bd693df2d2b9
 libraries/base/base.cabal | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libraries/base/base.cabal b/libraries/base/base.cabal
index 6da95b0..905bc49 100644
--- a/libraries/base/base.cabal
+++ b/libraries/base/base.cabal
@@ -398,3 +398,6 @@ Library
     -- We need to set the unit id to base (without a version number)
     -- as it's magic.
     ghc-options: -this-unit-id base
+
+    -- Make sure we don't accidentally regress into anti-patterns
+    ghc-options: -Wcompat -Wnoncanonical-monad-instances