The QuickCheck library swapped the order of the arguments of the 'cover'
function in version 2.12.  Version 0.3.4 of the Diff library still uses
the old argument order.  Swapping the argument order makes Diff work
with newer versions of QuickCheck.

See <https://github.com/commercialhaskell/stackage/issues/4289> for the
upstream bug report.

diff -ruN a/test/Test.hs b/test/Test.hs
--- a/test/Test.hs	2016-04-23 01:21:45.000000000 -0400
+++ b/test/Test.hs	2019-11-01 19:13:04.590770903 -0400
@@ -134,7 +134,7 @@
 prop_ppDiffR (DiffInput le ri) =
     let haskDiff=ppDiff $ getGroupedDiff le ri
         utilDiff= unsafePerformIO (runDiff (unlines le) (unlines ri))
-    in  cover (haskDiff == utilDiff) 90 "exact match" $
+    in  cover 90 (haskDiff == utilDiff) "exact match" $
                 classify (haskDiff == utilDiff) "exact match"
                         (div ((length haskDiff)*100) (length utilDiff) < 110) -- less than 10% bigger
     where
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<div class='path'>path: <a href='/guix/log/?id=2a87ab305e02ce4cd9ec14270d1c1a78ed868371'>root</a>/<a href='/guix/log/tests?id=2a87ab305e02ce4cd9ec14270d1c1a78ed868371'>tests</a>/<a href='/guix/log/tests/guix-archive.sh?id=2a87ab305e02ce4cd9ec14270d1c1a78ed868371'>guix-archive.sh</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/guix-archive.sh?id=2a87ab305e02ce4cd9ec14270d1c1a78ed868371&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/tests/guix-archive.sh?id=37dd69b44511dc73eb04bdebe8d82c9a0386338e'>tests: Fix checks for expected failures.</a><span class='msg-avail'>...<span class='msg-tooltip'>Addresses &lt;https://issues.guix.gnu.org/62406&gt;.

With 'set -e', a return status inverted with '!' does not cause the shell to
exit immediately.  Instead use '&amp;&amp; false' to indicate an expected failure.

* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh,
tests/guix-environment-container.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-home.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh, tests/guix-refresh.sh, tests/guix-shell.sh,
tests/guix-style.sh, tests/guix-system.sh: Replace uses of '! ...' with
'... &amp;&amp; false' or `test ! ...` as appropriate.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2020-12-15 17:32:09 +0100'>2020-12-15</span></td><td><a href='/guix/commit/tests/guix-archive.sh?id=ed7d02f7c198970ce3fe94bcee47592963326446'>serialization: 'restore-file' sets canonical timestamp and permissions.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/serialization.scm (restore-file): Set the permissions and mtime
of FILE.
* guix/nar.scm (finalize-store-file): Pass #:reset-timestamps? #f to
'register-items'.
* tests/nar.scm (rm-rf): Add 'chmod' calls to ensure files are writable.
("write-file + restore-file with symlinks"): Ensure every file in OUTPUT
passes 'canonical-file?'.
* tests/guix-archive.sh: Run "chmod -R +w" before "rm -rf".
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-09-28 21:06:36 -0500'>2020-09-28</span></td><td><a href='/guix/commit/tests/guix-archive.sh?id=d8934360d2453a403b5433e71d09188e4ed23b57'>tests: Simplify shell exit status negation;</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-lint.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh: Use the shell '!' keyword to negate command exit status
in place of 'if ...; then false; else true; fi'
</span></span></td><td>Eric Bavier</td></tr>