1 files changed, 10 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/ion/PurgeProtoChain.js b/js/src/jit-test/tests/ion/PurgeProtoChain.js
new file mode 100644
index 0000000000..b6319464ab
--- /dev/null
+++ b/js/src/jit-test/tests/ion/PurgeProtoChain.js
@@ -0,0 +1,10 @@
+// In a proto chain A-->B-->C, shadowing C.x with B.x must change C's shape.
+
+var C = {x: 1};
+var B = Object.create(C);
+var A = Object.create(B);
+for (var i = 0; i < 2000; i++) {
+    if (i == 1900)
+        B.x = 3;
+    assertEq(A.x, i < 1900 ? 1 : 3);
+}