Index: _weakrefset.py
===================================================================
--- _weakrefset.py	(revision 72555)
+++ _weakrefset.py	(working copy)
@@ -2,6 +2,7 @@
 # This code is separated-out because it is needed
 # by abc.py to load everything else at startup.
 
+import _abcoll
 from _weakref import ref
 
 __all__ = ['WeakSet']
@@ -118,6 +119,8 @@
         return self.data >= set(ref(item) for item in other)
 
     def __eq__(self, other):
+        if not isinstance(other, _abcoll.Iterable):
+            return False
         return self.data == set(ref(item) for item in other)
 
     def symmetric_difference(self, other):