--- /dev/null
+// Old mdo
+import "Prelude"
+
+main = mdo
+ x <- [1,2]
+ return $ print "\(x :: Integer)"
+--
+1
+2
+[(), ()]
+--
+// New mdo
+module {
+ features = [edo]
+}
+import "Prelude"
+
+main = mdo
+ x <- [1,2]
+ return $ print "\(x :: Integer)"
+--
+9:12-9:35: No side-effects allowed here.
\ No newline at end of file