diff --git a/implementation-contributed/javascriptcore/stress/regress-189571.js b/implementation-contributed/javascriptcore/stress/regress-189571.js
new file mode 100644
index 0000000000..8bde9cf24c
--- /dev/null
+++ b/implementation-contributed/javascriptcore/stress/regress-189571.js
@@ -0,0 +1,151 @@
+function assert(name, actual, expected) {
+    if (actual != expected) {
+        print("FAILED test " + name + ": expected " + expected + ", actual: " + actual);
+        throw "FAILED";
+    }
+}
+
+function checkResult(name, result, expectedK, expectedProp) {
+    assert(name, result[0], expectedK);
+    assert(name, result[1], expectedProp);
+}
+
+// ForIn on Indexed properties.
+
+function testIndexedProperties(o) {
+    for (var k in o) {
+        {
+            function k() { }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = [42];
+for (var i = 0; i < 10000; ++i) {
+    var result = testIndexedProperties(o);
+    checkResult("testIndexedProperties", result, "function k() { }", undefined);
+}
+
+function testIndexedProperties2(o) {
+    for (var k in o) {
+        {
+            k = "boo";
+            function k() { }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = [42];
+for (var i = 0; i < 10000; ++i) {
+    var result = testIndexedProperties2(o);
+    checkResult("testIndexedProperties2", result, "boo", undefined);
+}
+
+function testIndexedProperties3(o) {
+    for (var k in o) {
+        try {
+        } finally {
+            {
+                function k() { }
+            }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = [42];
+for (var i = 0; i < 10000; ++i) {
+    var result = testIndexedProperties3(o);
+    checkResult("testIndexedProperties3", result, "function k() { }", undefined);
+}
+
+function testIndexedProperties4(o) {
+    for (var k in o) {
+        try {
+        } finally {
+            {
+                k = "boo";
+                function k() { }
+            }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = [42];
+for (var i = 0; i < 10000; ++i) {
+    var result = testIndexedProperties4(o);
+    checkResult("testIndexedProperties4", result, "boo", undefined);
+}
+
+// ForIn on Structure properties.
+
+function testStructureProperties(o) {
+    for (var k in o) {
+        {
+            function k() { }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = {a: 42};
+for (var i = 0; i < 10000; ++i) {
+    var result = testStructureProperties(o);
+    checkResult("testStructureProperties", result, "function k() { }", undefined);
+}
+
+function testStructureProperties2(o) {
+    for (var k in o) {
+        {
+            k = 0x1234;
+            function k() { }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = {a: 42};
+for (var i = 0; i < 10000; ++i) {
+    var result = testStructureProperties2(o);
+    checkResult("testStructureProperties2", result, 0x1234, undefined);
+}
+
+function testStructureProperties3(o) {
+    for (var k in o) {
+        try {
+        } finally {
+            {
+                function k() { }
+            }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = {a: 42};
+for (var i = 0; i < 10000; ++i) {
+    var result = testStructureProperties3(o);
+    checkResult("testStructureProperties3", result, "function k() { }", undefined);
+}
+
+function testStructureProperties4(o) {
+    for (var k in o) {
+        try {
+        } finally {
+            {
+                k = 0x1234;
+                function k() { }
+            }
+        }
+        return [ k, o[k] ];
+    }
+}
+
+var o = {a: 42};
+for (var i = 0; i < 10000; ++i) {
+    var result = testStructureProperties4(o);
+    checkResult("testStructureProperties4", result, 0x1234, undefined);
+}