1 files changed, 36 insertions, 0 deletions
diff --git a/testsuite/tests/deSugar/should_compile/T3263-1.hs b/testsuite/tests/deSugar/should_compile/T3263-1.hs
new file mode 100644
index 0000000000..74249cd663
--- /dev/null
+++ b/testsuite/tests/deSugar/should_compile/T3263-1.hs
@@ -0,0 +1,36 @@
+-- Trac #3263.  New kind of warning on ignored monadic bindings
+
+module T3263 where
+
+nullM :: IO ()
+nullM = return ()
+
+nonNullM :: IO Int
+nonNullM = return 10
+
+-- No warning
+t1 = do
+  nonNullM
+
+-- No warning
+t2 = nonNullM
+
+-- No warning
+t3 = do
+  nullM
+  nonNullM
+
+-- Warning
+t4 = do
+  nonNullM
+  nullM
+
+-- No warning
+t5 = do
+  _ <- nonNullM
+  nullM
+
+-- Warning
+t6 = mdo
+  nonNullM
+  nullM
+\ No newline at end of file