1 files changed, 19 insertions, 0 deletions
diff --git a/testsuite/tests/lib/Concurrent/4876.hs b/testsuite/tests/lib/Concurrent/4876.hs
new file mode 100644
index 0000000000..68c2a871b8
--- /dev/null
+++ b/testsuite/tests/lib/Concurrent/4876.hs
@@ -0,0 +1,19 @@
+import System.Random
+import Control.Concurrent.SampleVar
+import Control.Concurrent
+import Control.Monad
+
+produce, consume :: SampleVar Int -> IO ()
+produce svar = do
+   b <- isEmptySampleVar svar
+   if b then writeSampleVar svar 3 else return ()
+
+consume svar = readSampleVar svar >>= print
+
+main = do
+   svar <- newEmptySampleVar
+   m <- newEmptyMVar
+   forkIO $ consume svar >> putMVar m ()
+   threadDelay 100000     -- 100 ms
+   produce svar
+   takeMVar m -- deadlocked before the fix in #4876