4 files changed, 11 insertions, 10 deletions
diff --git a/js/xpconnect/tests/chrome/test_xrayToJS.xul b/js/xpconnect/tests/chrome/test_xrayToJS.xul
index 8e6b0f8a4..aaacd4d00 100644
--- a/js/xpconnect/tests/chrome/test_xrayToJS.xul
+++ b/js/xpconnect/tests/chrome/test_xrayToJS.xul
@@ -235,8 +235,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=933681
   gPrototypeProperties['RegExp'] =
     ["constructor", "toSource", "toString", "compile", "exec", "test",
      Symbol.match, Symbol.replace, Symbol.search, Symbol.split,
-     "flags", "global", "ignoreCase", "multiline", "source", "sticky", "unicode",
-     "lastIndex"];
+     "flags", "global", "ignoreCase", "multiline", "source", "sticky", "unicode"];
   gConstructorProperties['RegExp'] =
     constructorProps(["input", "lastMatch", "lastParen",
                       "leftContext", "rightContext", "$1", "$2", "$3", "$4",
diff --git a/js/xpconnect/tests/unit/test_xray_regexp.js b/js/xpconnect/tests/unit/test_xray_regexp.js
new file mode 100644
index 000000000..4baffd63e
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xray_regexp.js
@@ -0,0 +1,9 @@
+const Cu = Components.utils;
+
+function run_test() {
+    var sandbox = Cu.Sandbox('http://www.example.com');
+    var regexp = Cu.evalInSandbox("/test/i", sandbox);
+    equal(RegExp.prototype.toString.call(regexp), "/test/i");
+    var prototype = Cu.evalInSandbox("RegExp.prototype", sandbox);
+    equal(typeof prototype.lastIndex, "undefined");
+}
diff --git a/js/xpconnect/tests/unit/xpcshell.ini b/js/xpconnect/tests/unit/xpcshell.ini
index 99d44b975..12648d3ec 100644
--- a/js/xpconnect/tests/unit/xpcshell.ini
+++ b/js/xpconnect/tests/unit/xpcshell.ini
@@ -133,5 +133,6 @@ head = head_watchdog.js
 [test_xrayed_iterator.js]
 [test_xray_SavedFrame.js]
 [test_xray_SavedFrame-02.js]
+[test_xray_regexp.js]
 [test_resolve_dead_promise.js]
 [test_asyncLoadSubScriptError.js]
diff --git a/js/xpconnect/wrappers/XrayWrapper.cpp b/js/xpconnect/wrappers/XrayWrapper.cpp
index 8011d207f..48a9fdc68 100644
--- a/js/xpconnect/wrappers/XrayWrapper.cpp
+++ b/js/xpconnect/wrappers/XrayWrapper.cpp
@@ -636,10 +636,6 @@ JSXrayTraits::resolveOwnProperty(JSContext* cx, const Wrapper& jsWrapper,
         return true;
     }
 
-    // Handle the 'lastIndex' property for RegExp prototypes.
-    if (key == JSProto_RegExp && id == GetJSIDByIndex(cx, XPCJSContext::IDX_LASTINDEX))
-        return getOwnPropertyFromWrapperIfSafe(cx, wrapper, id, desc);
-
     // Grab the JSClass. We require all Xrayable classes to have a ClassSpec.
     const js::Class* clasp = js::GetObjectClass(target);
     MOZ_ASSERT(clasp->specDefined());
@@ -881,10 +877,6 @@ JSXrayTraits::enumerateNames(JSContext* cx, HandleObject wrapper, unsigned flags
     if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_CONSTRUCTOR)))
         return false;
 
-    // For RegExp protoypes, add the 'lastIndex' property.
-    if (key == JSProto_RegExp && !props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_LASTINDEX)))
-        return false;
-
     // Grab the JSClass. We require all Xrayable classes to have a ClassSpec.
     const js::Class* clasp = js::GetObjectClass(target);
     MOZ_ASSERT(clasp->specDefined());