This patch is taken from upstream.  It fixes a test to work with GHC 8.6.
The paths have been slightly altered to work with the release tarball.

See <https://github.com/simonmar/monad-par/issues/66>.

From e20f81c8060208e4fb038e8f0e0668b41d72a6fb Mon Sep 17 00:00:00 2001
From: Clint Adams <clint@debian.org>
Date: Sat, 31 Aug 2019 14:12:34 -0400
Subject: [PATCH] Use a case statement instead of pattern-matching in
 case_test_diamond

This avoids the need for a MonadFail instance.  Closes #66
---
 monad-par/tests/ParTests_shared.hs | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/tests/ParTests_shared.hs b/tests/ParTests_shared.hs
index 31f438d..b2de50c 100644
--- a/tests/ParTests_shared.hs
+++ b/tests/ParTests_shared.hs
@@ -109,12 +109,15 @@ case_test_diamond :: Assertion
 case_test_diamond = 9 @=? (m :: Int)
  where 
   m = runPar $ do
-      [a,b,c,d] <- sequence [new,new,new,new]
-      fork $ do x <- get a; put b (x+1)
-      fork $ do x <- get a; put c (x+2)
-      fork $ do x <- get b; y <- get c; put d (x+y)
-      fork $ do put a 3
-      get d
+      abcd <- sequence [new,new,new,new]
+      case abcd of
+          [a,b,c,d] -> do
+              fork $ do x <- get a; put b (x+1)
+              fork $ do x <- get a; put c (x+2)
+              fork $ do x <- get b; y <- get c; put d (x+y)
+              fork $ do put a 3
+              get d
+          _ -> error "Oops"
 
 -- | Violate IVar single-assignment:
 --
-- 
2.23.0

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<div class='path'>path: <a href='/guix/log/?id=139970c8066fe5cfb6adbc20346a73c0a7cec202'>root</a>/<a href='/guix/log/tests?id=139970c8066fe5cfb6adbc20346a73c0a7cec202'>tests</a>/<a href='/guix/log/tests/services.scm?id=139970c8066fe5cfb6adbc20346a73c0a7cec202'>services.scm</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/services.scm?id=139970c8066fe5cfb6adbc20346a73c0a7cec202&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-04-10 01:24:30 +0200'>2022-04-10</span></td><td><a href='/guix/commit/tests/services.scm?id=ec6a585ee2fd91c857276479411eedd0756e0093'>services: Test 'shepherd-service-upgrade' with transient services.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to eeb8ac43c8c0b0cc69422766070dbefc55f5c5c1.

* tests/services.scm ("shepherd-service-upgrade: transient service"):
New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-04-10 01:15:13 +0200'>2022-04-10</span></td><td><a href='/guix/commit/tests/services.scm?id=e25eca35ff04e4234d0376fbb9a8e146869772c8'>services: herd: Adjust to &lt;live-service&gt; changes.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to a2c759c8304c461d096ab763568e7f71546ff4e8.

* guix/scripts/system/reconfigure.scm (running-services): Fill in the
'transient?' field of &lt;live-service&gt;.
* tests/services.scm ("shepherd-service-upgrade: one unchanged, one upgraded, one new")
("shepherd-service-upgrade: service depended on is not unloaded")
("shepherd-service-upgrade: obsolete services that depend on each
other"): Adjust calls to 'live-service'.
</span></span></td><td>Ludovic Courtès</td></tr>