Lock the prototype of internal classes.

src/date.js

Index: src/date.js
diff --git a/src/date.js b/src/date.js
index 79b846d4a7060efc938990330cf8396b07224073..8a43755ade614900a783fa81730442852db4b97c 100644
--- a/src/date.js
+++ b/src/date.js
@@ -1049,6 +1049,7 @@ function ResetDateCache() {
 // -------------------------------------------------------------------
 
 function SetupDate() {

[Erik Corry, 2011/08/31 05:46:04]

SetupDate -> SetUpDate

[Lasse Reichstein, 2011/09/01 13:30:42]

I can do better - and make this a direct call of a function literal. 
I'm considering not making it a function at all.

+  %AssertIsBootstrapping();
   // Setup non-enumerable properties of the Date object itself.
   InstallFunctions($Date, DONT_ENUM, $Array(
     "UTC", DateUTC,