diff --git a/tests/test-double-merge b/tests/test-double-merge
new file mode 100755
--- /dev/null
+++ b/tests/test-double-merge
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+hg init repo
+cd repo
+
+echo line 1 > foo
+hg ci -qAm 'add foo' -d "1000000 0"
+
+# copy foo to bar and change both files
+hg cp foo bar
+echo line 2-1 >> foo
+echo line 2-2 >> bar
+hg ci -m 'cp foo bar; change both' -d "1000000 0"
+
+# in another branch, change foo in a way that doesn't conflict with
+# the other changes
+hg up -qC 0
+echo line 0 >| foo
+hg cat foo >> foo
+hg ci -m 'change foo' -d "1000000 0"
+
+# we get conflicts that shouldn't be there
+hg merge --debug
+
+echo "-- foo --"
+cat foo
+
+echo "-- bar --"
+cat bar
+