1 files changed, 37 insertions, 0 deletions
diff --git a/js/src/tests/non262/generators/delegating-yield-5.js b/js/src/tests/non262/generators/delegating-yield-5.js
new file mode 100644
index 0000000000..f4376743b0
--- /dev/null
+++ b/js/src/tests/non262/generators/delegating-yield-5.js
@@ -0,0 +1,37 @@
+// Test that a deep yield* chain re-yields received results without
+// re-boxing.
+
+function results(results) {
+    var i = 0;
+    function next() {
+        return results[i++];
+    }
+    var iter = { next: next };
+    var ret = {};
+    ret[Symbol.iterator] = function () { return iter; }
+    return ret;
+}
+
+function* yield_results(expected, n) {
+    return yield* n ? yield_results(expected, n - 1) : results(expected);
+}
+
+function collect_results(iterable) {
+    var ret = [];
+    var result;
+    var iter = iterable[Symbol.iterator]();
+    do {
+        result = iter.next();
+        ret.push(result);
+    } while (!result.done);
+    return ret;
+}
+
+// We have to put a full result for the end, because the return will re-box.
+var expected = [{value: 1}, {value: 34, done: true}];
+
+assertDeepEq(expected, collect_results(results(expected)));
+assertDeepEq(expected, collect_results(yield_results(expected, 20)));
+
+if (typeof reportCompare == "function")
+    reportCompare(true, true);