diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testBug502914.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testBug502914.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,19 @@
+function testBug502914() {
+    // Assigning a non-function to a function-valued property on trace should
+    // bump the shape.
+    function f1() {}
+    function C() {}
+    var x = C.prototype = {m: f1};
+    x.m();  // brand scope
+    var arr = [new C, new C, new C, x];
+    try {
+        for (var i = 0; i < 4; i++) {
+            arr[i].m = 12;
+            x.m();  // should throw last time through
+        }
+    } catch (exc) {
+        return exc.constructor.name;
+    }
+    return "no exception";
+}
+assertEq(testBug502914(), "TypeError");