1 files changed, 31 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/fields/ion-private-idempotent.js b/js/src/jit-test/tests/fields/ion-private-idempotent.js
new file mode 100644
index 0000000000..139735d62d
--- /dev/null
+++ b/js/src/jit-test/tests/fields/ion-private-idempotent.js
@@ -0,0 +1,31 @@
+var acc = 0;
+const loopCount = 100;
+
+class A {
+  #x = 1;
+  static loopRead(o) {
+    for (var i = 0; i < loopCount; i++) {
+      // If this getelem were hoisted out of the loop,
+      // we need the IC that is attached to that to
+      // correctly throw if .#x is not in o.
+      var b = o.#x;
+      acc += 1;
+    }
+  }
+};
+
+// Two non-A objects, because we're concerned not about the first
+// attempt to read .#x from a non A, but the second, because if
+// we attach the wrong IC, we'll attach an IC that provides
+// regular object semantics, which would be to return undefined.
+var array = [new A, new A, new A, {}, {}];
+for (var e of array) {
+  acc = 0;
+  try {
+    A.loopRead(e);
+    assertEq(acc, loopCount);
+  } catch (e) {
+    assertEq(e instanceof TypeError, true);
+    assertEq(acc, 0);
+  }
+}