diff -r 149490bbd260 Lib/collections/__init__.py
--- a/Lib/collections/__init__.py	Sat Nov 01 07:40:22 2014 -0700
+++ b/Lib/collections/__init__.py	Wed Nov 05 09:47:12 2014 -0800
@@ -769,20 +769,22 @@ class Counter(dict):
 
     def __iand__(self, other):
         '''Inplace intersection is the minimum of corresponding counts.
 
         >>> c = Counter('abbb')
         >>> c &= Counter('bcc')
         >>> c
         Counter({'b': 1})
 
         '''
+        if not hasattr(other, '__getitem__'):
+            raise TypeError('%r is not subscriptable' % type(other))
         for elem, count in self.items():
             other_count = other[elem]
             if other_count < count:
                 self[elem] = other_count
         return self._keep_positive()
 
 
 ########################################################################
 ###  ChainMap (helper for configparser and string.Template)
 ########################################################################