Function#toMethod: check `newHome` before `this`

src/harmony-classes.js

Index: src/harmony-classes.js
diff --git a/src/harmony-classes.js b/src/harmony-classes.js
index b6605a902c3059bef54ad3b0956931fcaf19e1d3..9171bb368308b0e87d07c91020a2e34f86be9938 100644
--- a/src/harmony-classes.js
+++ b/src/harmony-classes.js
@@ -9,18 +9,18 @@
 
 
 (function() {
+  // ES6 draft 12-06-13, section 19.2.3.5.
   function FunctionToMethod(homeObject) {
-    if (!IS_SPEC_FUNCTION(this)) {
-      throw MakeTypeError('toMethod_non_function',
-                          [%ToString(this), typeof this]);
-
-    }
-
     if (!IS_SPEC_OBJECT(homeObject)) {
       throw MakeTypeError('toMethod_non_object',
                           [%ToString(homeObject)]);
     }
 
+    if (!IS_SPEC_FUNCTION(this)) {
+      throw MakeTypeError('toMethod_non_function',
+                          [%ToString(this), typeof this]);
+    }
+
     return %ToMethod(this, homeObject);
   }