diff --git a/js/src/jit-test/tests/jaeger/inline/bug645645.js b/js/src/jit-test/tests/jaeger/inline/bug645645.js
new file mode 100644
index 00000000000..6649b559edc
--- /dev/null
+++ b/js/src/jit-test/tests/jaeger/inline/bug645645.js
@@ -0,0 +1,4 @@
+function f() {
+    f = Math.x;
+}
+f();
diff --git a/js/src/jsanalyze.cpp b/js/src/jsanalyze.cpp
index 8b71153eba5..99ae37666bf 100644
--- a/js/src/jsanalyze.cpp
+++ b/js/src/jsanalyze.cpp
@@ -309,6 +309,7 @@ Script::analyze(JSContext *cx, JSScript *script)
 
     isInlineable = true;
     if (script->nClosedArgs || script->nClosedVars ||
+        (script->fun && script->fun->isHeavyweight()) ||
         script->usesEval || script->usesArguments || cx->compartment->debugMode) {
         isInlineable = false;
     }