1 files changed, 15 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/collections/Map-gc-4.js b/js/src/jit-test/tests/collections/Map-gc-4.js
new file mode 100644
index 0000000000..5597ec1bbf
--- /dev/null
+++ b/js/src/jit-test/tests/collections/Map-gc-4.js
@@ -0,0 +1,15 @@
+// Bug 770954.
+
+gczeal(4);
+var s = new Set;
+s.add(-0);
+s.add(0);
+assertEq(s.delete(-0), true);
+assertEq(s.has(0), (false  ));
+assertEq(s.has(-0), false);
+var m = new Map;
+m.set(-0, 'x');
+assertEq(m.has(0), true);
+assertEq(m.get(0), 'x');
+assertEq(m.has(-0), true);
+assertEq(m.delete(-0), true);