diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/gc-09.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/gc-09.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+// Bug 717104 - Unreachable debuggee globals should not keep their debuggers
+// alive. The loop is to defeat conservative stack scanning; if the same stack
+// locations are used each time through the loop, at least three of the
+// debuggers should be collected.
+
+for (var i = 0; i < 4; i++) {
+    var g = newGlobal();
+    var dbg = new Debugger(g);
+    dbg.onDebuggerStatement = function () { throw "FAIL"; };
+    dbg.o = makeFinalizeObserver();
+    dbg.loop = g; // make a cycle of strong references with dbg and g
+}
+
+gc();
+assertEq(finalizeCount() > 0, true);