diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/gc-02.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/gc-02.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,28 @@
+// Dispatching an event to a debugger must keep enough of it gc-alive to avoid
+// crashing.
+
+var g = newGlobal();
+var hits;
+
+function addDebug() {
+    // The loop is here to defeat the conservative GC. :-\
+    for (var i = 0; i < 4; i++) {
+        var dbg = new Debugger(g);
+        dbg.onDebuggerStatement = function (stack) {
+            hits++;
+            this.enabled = false;
+            this.onDebuggerStatement = undefined;
+            gc();
+        };
+        if (i > 0) {
+            dbg.enabled = false;
+            dbg.onDebuggerStatement = undefined;
+            dbg = null;
+        }
+    }
+}
+
+addDebug();
+hits = 0;
+g.eval("debugger;");
+assertEq(hits, 1);