diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/auto-regress/bug679799.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/auto-regress/bug679799.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,16 @@
+// Binary: cache/js-dbg-64-2d95fc517e57-linux
+// Flags: -m -n -a
+//
+
+function test()
+{
+  var x = { "0": 3, "-0": 7 };
+  try {
+    delete x["-0"];
+    if ("-0" in x)
+      throw "0 not in x after insertion of 0 property";
+    this ["-0"] = 7;
+  } catch(ex) {}
+}
+test();
+test();