diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug980860.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug980860.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,34 @@
+if (typeof TypedObject === 'undefined')
+    quit();
+
+var StructType = TypedObject.StructType;
+var uint8 = TypedObject.uint8;
+
+function check(c) {
+  assertEq(c.r, 129);
+}
+
+function run() {
+  var RgbColor = new StructType({r: uint8, g: uint8, b: uint8});
+  var Fade = new StructType({from: RgbColor, to: RgbColor});
+
+  var BrgColor = new StructType({b: uint8, r: uint8, g: uint8});
+  var BrgFade = new StructType({from: BrgColor, to: BrgColor});
+
+  var gray = new RgbColor({r: 129, g: 128, b: 127});
+
+  var fade = new Fade({from: gray, to: gray});
+  fade.to = {r: 129, g: 128, b: 127};
+
+  var brgGray = new BrgColor(gray);
+  fade.from = brgGray;
+
+  var brgFade = new BrgFade(fade);
+
+  check(fade.to);
+  check(brgFade.to);
+  check(fade.to);
+  check(brgFade.to);
+}
+
+run();