diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/parallel/Array-mapPar-assign-to-def-prop.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/parallel/Array-mapPar-assign-to-def-prop.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,10 @@
+load(libdir + "parallelarray-helpers.js");
+
+function wrapInObject(v) {
+    var obj = {f: 2};
+    obj.f += v;
+    return obj;
+}
+
+if (getBuildConfiguration().parallelJS)
+  assertArraySeqParResultsEq(range(0, 64), "map", wrapInObject);