diff --git a/js/src/methodjit/FrameState-inl.h b/js/src/methodjit/FrameState-inl.h
index 1189615df6e..e460c493ad6 100644
--- a/js/src/methodjit/FrameState-inl.h
+++ b/js/src/methodjit/FrameState-inl.h
@@ -706,7 +706,6 @@ FrameState::eviscerate(FrameEntry *fe)
 inline void
 FrameState::addEscaping(uint32 local)
 {
-    JS_ASSERT(!escaping[local]);
     escaping[local] = 1;
 }
 
diff --git a/js/src/trace-test/tests/jaeger/bug580703.js b/js/src/trace-test/tests/jaeger/bug580703.js
new file mode 100644
index 00000000000..78d85df051a
--- /dev/null
+++ b/js/src/trace-test/tests/jaeger/bug580703.js
@@ -0,0 +1,9 @@
+
+
+let(w)(function () {
+    w
+})
+let(e)(function () {
+    e
+})
+