--- a/js/src/jsobj.cpp
+++ b/js/src/jsobj.cpp
@@ -1183,56 +1183,54 @@ obj_watch_handler(JSContext *cx, JSObjec
     return Invoke(cx, ObjectValue(*obj), ObjectOrNullValue(callable), ArrayLength(argv), argv, nvp);
 }
 
 static JSBool
 obj_watch(JSContext *cx, unsigned argc, Value *vp)
 {
     if (argc <= 1) {
         js_ReportMissingArg(cx, *vp, 1);
-        return JS_FALSE;
+        return false;
     }
 
     JSObject *callable = js_ValueToCallableObject(cx, &vp[3], 0);
     if (!callable)
-        return JS_FALSE;
+        return false;
 
     jsid propid;
     if (!ValueToId(cx, vp[2], &propid))
-        return JS_FALSE;
+        return false;
 
     JSObject *obj = ToObject(cx, &vp[1]);
     if (!obj)
         return false;
 
     Value tmp;
     unsigned attrs;
     if (!CheckAccess(cx, obj, propid, JSACC_WATCH, &tmp, &attrs))
-        return JS_FALSE;
+        return false;
 
     vp->setUndefined();
 
-    if (attrs & JSPROP_READONLY)
-        return JS_TRUE;
     if (obj->isDenseArray() && !obj->makeDenseArraySlow(cx))
-        return JS_FALSE;
+        return false;
     return JS_SetWatchPoint(cx, obj, propid, obj_watch_handler, callable);
 }
 
 static JSBool
 obj_unwatch(JSContext *cx, unsigned argc, Value *vp)
 {
     JSObject *obj = ToObject(cx, &vp[1]);
     if (!obj)
         return false;
     vp->setUndefined();
     jsid id;
     if (argc != 0) {
         if (!ValueToId(cx, vp[2], &id))
-            return JS_FALSE;
+            return false;
     } else {
         id = JSID_VOID;
     }
     return JS_ClearWatchPoint(cx, obj, id, NULL, NULL);
 }
 
 #endif /* JS_HAS_OBJ_WATCHPOINT */
 

--- a/js/src/tests/js1_8_5/extensions/jstests.list
+++ b/js/src/tests/js1_8_5/extensions/jstests.list
@@ -29,16 +29,18 @@ skip-if(!xulRuntime.shell) script clone-
 skip-if(!xulRuntime.shell) script clone-forge.js
 skip-if(!xulRuntime.shell) script clone-complex-object.js
 script set-property-non-extensible.js
 script recursion.js
 script findReferences-01.js
 script findReferences-02.js
 script findReferences-03.js
 script findReferences-04.js
+script regress-604781-1.js
+script regress-604781-2.js
 script regress-627859.js
 script regress-627984-1.js
 script regress-627984-2.js
 script regress-627984-3.js
 script regress-627984-4.js
 script regress-627984-5.js
 script regress-627984-6.js
 script regress-627984-7.js

new file mode 100644
--- /dev/null
+++ b/js/src/tests/js1_8_5/extensions/regress-604781-1.js
@@ -0,0 +1,24 @@
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/licenses/publicdomain/
+
+var watcherCount, setterCount;
+function watcher(id, oldval, newval) { watcherCount++; return newval; }
+function setter(newval) { setterCount++; }
+
+var p = { set x(v) { setter(v); } };
+p.watch('x', watcher);
+
+watcherCount = setterCount = 0;
+p.x = 2;
+assertEq(setterCount, 1);
+assertEq(watcherCount, 1);
+
+var o = Object.defineProperty({}, 'x', { set:setter, enumerable:true, configurable:true });
+o.watch('x', watcher);
+
+watcherCount = setterCount = 0;
+o.x = 2;
+assertEq(setterCount, 1);
+assertEq(watcherCount, 1);
+
+reportCompare(0, 0, 'ok');

new file mode 100644
--- /dev/null
+++ b/js/src/tests/js1_8_5/extensions/regress-604781-2.js
@@ -0,0 +1,13 @@
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/licenses/publicdomain/
+
+var log;
+function watcher(id, old, newval) { log += 'watcher'; return newval; }
+var o = { set x(v) { log += 'setter'; } };
+o.watch('x', watcher);
+Object.defineProperty(o, 'x', {value: 3, writable: true});
+log = '';
+o.x = 3;
+assertEq(log, 'watcher');
+
+reportCompare(0, 0, 'ok');