1 files changed, 41 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/cacheir/object-is-prototype-of.js b/js/src/jit-test/tests/cacheir/object-is-prototype-of.js
new file mode 100644
index 0000000000..1ecc441f47
--- /dev/null
+++ b/js/src/jit-test/tests/cacheir/object-is-prototype-of.js
@@ -0,0 +1,41 @@
+function testPrimitive() {
+  for (var i = 0; i < 100; ++i) {
+    // Null and undefined.
+    assertEq(Object.prototype.isPrototypeOf(null), false);
+    assertEq(Object.prototype.isPrototypeOf(void 0), false);
+
+    // Primitive wrappers.
+    assertEq(String.prototype.isPrototypeOf(""), false);
+    assertEq(Number.prototype.isPrototypeOf(0), false);
+    assertEq(Boolean.prototype.isPrototypeOf(true), false);
+    assertEq(BigInt.prototype.isPrototypeOf(0n), false);
+    assertEq(Symbol.prototype.isPrototypeOf(Symbol.hasInstance), false);
+  }
+}
+testPrimitive();
+
+function testObject() {
+  for (var i = 0; i < 100; ++i) {
+    assertEq(Object.prototype.isPrototypeOf({}), true);
+    assertEq(Object.prototype.isPrototypeOf([]), true);
+
+    assertEq(Array.prototype.isPrototypeOf({}), false);
+    assertEq(Array.prototype.isPrototypeOf([]), true);
+  }
+}
+testObject();
+
+function testProxy() {
+  var proxy = new Proxy({}, new Proxy({}, {
+    get(t, pk, r) {
+      assertEq(pk, "getPrototypeOf");
+      return Reflect.get(t, pk, r);
+    }
+  }));
+
+  for (var i = 0; i < 100; ++i) {
+    assertEq(Object.prototype.isPrototypeOf(proxy), true);
+    assertEq(Array.prototype.isPrototypeOf(proxy), false);
+  }
+}
+testProxy();