diff --git a/js/src/jit-test/tests/ion/bug1213552.js b/js/src/jit-test/tests/ion/bug1213552.js
new file mode 100644
index 000000000000..f1d475dd6dc4
--- /dev/null
+++ b/js/src/jit-test/tests/ion/bug1213552.js
@@ -0,0 +1,4 @@
+this.x1 = 'y';
+// evalcx is like evaluate and not eval, and so can introduce a global let binding.
+evalcx("let x1 = 'z';", this);
+assertEq(x1, 'z');