Implement Object.defineProperty for proxies.

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index 841c5180a3df0c7d24a82d1b52e56b576454c3b7..b9281070a7670f6d38b1e7e5ddea603d551e9cc2 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -195,6 +195,7 @@ function FormatMessage(message) {
       non_extensible_proto:         ["%0", " is not extensible"],
       handler_non_object:           ["Proxy.", "%0", " called with non-object as handler"],
       handler_trap_missing:         ["Proxy handler ", "%0", " has no '", "%1", "' trap"],
+      handler_failed:               ["Proxy handler ", "%0", " returned false for '", "%1", "' trap"],

[Kevin Millikin (Chromium), 2011/07/07 08:12:02]

I wonder if there's a better message?  Couldn't the handler have returned 0 or
undefined or...?

I have no concrete suggestion right now.

[rossberg, 2011/07/07 09:19:32]

Hm, me neither. The return type morally is a Boolean, so I guess users will know
how to read this.

       proxy_prop_not_configurable:  ["Trap ", "%1", " of proxy handler ", "%0", " returned non-configurable descriptor for property ", "%2"],
       proxy_non_object_prop_names:  ["Trap ", "%1", " returned non-object ", "%0"],
       proxy_repeated_prop_name:     ["Trap ", "%1", " returned repeated property name ", "%2"],