From 5c1bb4a2869035308074b1191f8414f6a2287a20 Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Tue, 15 Oct 2019 16:36:24 -0400
Subject: [PATCH] testsuite: Add test for ghc#16707

---
 tests/T16707.hs | 20 ++++++++++++++++++++
 tests/all.T     |  1 +
 2 files changed, 21 insertions(+)
 create mode 100644 tests/T16707.hs

diff --git a/tests/T16707.hs b/tests/T16707.hs
new file mode 100644
index 0000000..61e723c
--- /dev/null
+++ b/tests/T16707.hs
@@ -0,0 +1,20 @@
+import Control.Concurrent
+import Control.Concurrent.STM
+import Debug.Trace
+
+main :: IO ()
+main = (`mapM_` [1..1000]) $ \_ -> do
+  traceEventIO "(((("
+
+  x <- newTVarIO False
+
+  forkIO $ atomically $ writeTVar x True
+
+  traceEventIO "----"
+
+  atomically $ do  -- hangs in the second iteration
+    _ <- readTVar x
+    writeTVar x True `orElse` return ()
+
+  threadDelay 100000
+  traceEventIO "))))"
diff --git a/tests/all.T b/tests/all.T
index c1138fa..2bc0f69 100644
--- a/tests/all.T
+++ b/tests/all.T
@@ -26,3 +26,4 @@ test('stm065', normal, compile_and_run, ['-package stm'])
 test('cloneTChan001', normal, compile_and_run, ['-package stm'])
 
 test('T15136', extra_run_opts('20'), compile_and_run, ['-package stm'])
+test('T16707', normal, compile_and_run, [''])