diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug861439.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug861439.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,14 @@
+
+try {
+    x = evalcx('')
+    toSource = (function() {
+        x = (new WeakMap).get(function() {})
+    })
+    valueOf = (function() {
+        schedulegc(x)
+    })
+    this + ''
+    for (v of this) {}
+} catch (e) {}
+gc()
+this + 1