Fix implementation of == to correctly convert Date objects to primitives.

src/runtime.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 31 matching lines @@
 // The following const declarations are shared with other native JS files.
 // They are all declared at this one spot to avoid const redeclaration errors.
 const $Object = global.Object;
 const $Array = global.Array;
 const $String = global.String;
 const $Number = global.Number;
 const $Function = global.Function;
 const $Boolean = global.Boolean;
 const $NaN = 0/0;
 
-
-// ECMA-262, section 11.9.1, page 55.
+// ECMA-262 Section 11.9.3.
 function EQUALS(y) {
   if (IS_STRING(this) && IS_STRING(y)) return %StringEquals(this, y);
   var x = this;
 
-  // NOTE: We use iteration instead of recursion, because it is
-  // difficult to call EQUALS with the correct setting of 'this' in
-  // an efficient way.
   while (true) {
     if (IS_NUMBER(x)) {
-      if (y == null) return 1;  // not equal
-      return %NumberEquals(x, %ToNumber(y));
+      while (true) {
+        if (IS_NUMBER(y)) return %NumberEquals(x, y);
+        if (IS_NULL_OR_UNDEFINED(y)) return 1;  // not equal
+        if (!IS_SPEC_OBJECT(y)) {
+          // String or boolean.
+          return %NumberEquals(x, %ToNumber(y));
+        }
+        y = %ToPrimitive(y, NO_HINT);
+      }
     } else if (IS_STRING(x)) {
-      if (IS_STRING(y)) return %StringEquals(x, y);
+      while (true) {
+        if (IS_STRING(y)) return %StringEquals(x, y);
+        if (IS_NUMBER(y)) return %NumberEquals(%ToNumber(x), y);
+        if (IS_BOOLEAN(y)) return %NumberEquals(%ToNumber(x), %ToNumber(y));
+        if (IS_NULL_OR_UNDEFINED(y)) return 1;  // not equal
+        y = %ToPrimitive(y, NO_HINT);
+      }
+    } else if (IS_BOOLEAN(x)) {
+      if (IS_BOOLEAN(y)) return %_ObjectEquals(x, y) ? 0 : 1;
+      if (IS_NULL_OR_UNDEFINED(y)) return 1;
       if (IS_NUMBER(y)) return %NumberEquals(%ToNumber(x), y);
-      if (IS_BOOLEAN(y)) return %NumberEquals(%ToNumber(x), %ToNumber(y));
-      if (y == null) return 1;  // not equal
+      if (IS_STRING(y)) return %NumberEquals(%ToNumber(x), %ToNumber(y));
+      // y is object.
+      x = %ToNumber(x);
       y = %ToPrimitive(y, NO_HINT);
-    } else if (IS_BOOLEAN(x)) {
-      if (IS_BOOLEAN(y)) {
-        return %_ObjectEquals(x, y) ? 0 : 1;
-      }
-      if (y == null) return 1;  // not equal
-      return %NumberEquals(%ToNumber(x), %ToNumber(y));
-    } else if (x == null) {
-      // NOTE: This checks for both null and undefined.
-      return (y == null) ? 0 : 1;
+    } else if (IS_NULL_OR_UNDEFINED(x)) {
+      return IS_NULL_OR_UNDEFINED(y) ? 0 : 1;
     } else {
-      // x is not a number, boolean, null or undefined.
-      if (y == null) return 1;  // not equal
+      // x is an object.
       if (IS_SPEC_OBJECT(y)) {
         return %_ObjectEquals(x, y) ? 0 : 1;
       }
-
+      if (IS_NULL_OR_UNDEFINED(y)) return 1;  // not equal
+      if (IS_BOOLEAN(y)) y = %ToNumber(y);
       x = %ToPrimitive(x, NO_HINT);
     }
   }
 }
 
 // ECMA-262, section 11.9.4, page 56.
 function STRICT_EQUALS(x) {
   if (IS_STRING(this)) {
     if (!IS_STRING(x)) return 1;  // not equal
     return %StringEquals(this, x);
@@ skipping 537 matching lines @@
   throw %MakeTypeError('cannot_convert_to_primitive', []);
 }
 
 
 // NOTE: Setting the prototype for Array must take place as early as
 // possible due to code generation for array literals.  When
 // generating code for a array literal a boilerplate array is created
 // that is cloned when running the code.  It is essiential that the
 // boilerplate gets the right prototype.
 %FunctionSetPrototype($Array, new $Array(0));