Check that constructor is a FunctionMirror before calling .name()

src/mirror-delay.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 746 matching lines @@
     result[i] = MakeMirror(result[i]);
   }
 
   return result;
 };
 
 
 ObjectMirror.prototype.toText = function() {
   var name;
   var ctor = this.constructorFunction();
-  if (ctor.isUndefined()) {
+  if (!ctor.isFunction()) {
     name = this.className();
   } else {
     name = ctor.name();
     if (!name) {
       name = this.className();
     }
   }
   return '#<' + builtins.GetInstanceName(name) + '>';
 };
 
@@ skipping 1490 matching lines @@
   }
   if (!isFinite(value)) {
     if (value > 0) {
       return 'Infinity';
     } else {
       return '-Infinity';
     }
   }
   return value; 
 }