diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index d6a0cc7e563d..7a09fc86339d 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -1467,7 +1467,6 @@ struct JSExtendedClass {
 #define JSCLASS_NEW_ENUMERATE           (1<<1)  /* has JSNewEnumerateOp hook */
 #define JSCLASS_NEW_RESOLVE             (1<<2)  /* has JSNewResolveOp hook */
 #define JSCLASS_PRIVATE_IS_NSISUPPORTS  (1<<3)  /* private is (nsISupports *) */
-#define JSCLASS_SHARE_ALL_PROPERTIES    (1<<4)  /* all properties are SHARED */
 #define JSCLASS_NEW_RESOLVE_GETS_START  (1<<5)  /* JSNewResolveOp gets starting
                                                    object in prototype chain
                                                    passed in via *objp in/out
diff --git a/js/src/jsobj.cpp b/js/src/jsobj.cpp
index 49b5d8e96dd9..bc5e9928c15c 100644
--- a/js/src/jsobj.cpp
+++ b/js/src/jsobj.cpp
@@ -4259,9 +4259,6 @@ js_DefineNativeProperty(JSContext *cx, JSObject *obj, jsid id, jsval value,
     added = false;
     if (!sprop) {
         /* Add a new property, or replace an existing one of the same id. */
-        if (clasp->flags & JSCLASS_SHARE_ALL_PROPERTIES)
-            attrs |= JSPROP_SHARED;
-
         if (defineHow & JSDNP_SET_METHOD) {
             JS_ASSERT(clasp == &js_ObjectClass);
             JS_ASSERT(VALUE_IS_FUNCTION(cx, value));
@@ -5126,9 +5123,6 @@ js_SetPropertyHelper(JSContext *cx, JSObject *obj, jsid id, uintN defineHow,
             return JS_FALSE;
         }
 
-        if (clasp->flags & JSCLASS_SHARE_ALL_PROPERTIES)
-            attrs |= JSPROP_SHARED;
-
         /*
          * Check for Object class here to avoid defining a method on a class
          * with magic resolve, addProperty, getProperty, etc. hooks.
diff --git a/js/src/jsops.cpp b/js/src/jsops.cpp
index e1207610ebc4..c5b0e56942c2 100644
--- a/js/src/jsops.cpp
+++ b/js/src/jsops.cpp
@@ -1739,9 +1739,6 @@ BEGIN_CASE(JSOP_SETMETHOD)
                  * inline compensation code here, depending on
                  * real-world workloads.
                  */
-                JS_ASSERT(!(obj->getClass()->flags &
-                            JSCLASS_SHARE_ALL_PROPERTIES));
-
                 PCMETER(cache->pchits++);
                 PCMETER(cache->addpchits++);
 
@@ -3346,7 +3343,6 @@ BEGIN_CASE(JSOP_INITMETHOD)
     obj = JSVAL_TO_OBJECT(lval);
     JS_ASSERT(obj->isNative());
     JS_ASSERT(!obj->getClass()->reserveSlots);
-    JS_ASSERT(!(obj->getClass()->flags & JSCLASS_SHARE_ALL_PROPERTIES));
 
     JSScope *scope = obj->scope();
     PropertyCacheEntry *entry;