[Python-Dev] 'unhashable type' and new style classes

Thomas Heller theller@python.net
30 Dec 2002 16:38:08 +0100


This code

  class X:
      def __cmp__(self, other):
          return 1

  c1 = X()

  d = {}
  d[c1] = None

raises a TypeError, unhashable type, since the class does
not define a __hash__ method.

This error is no longer raised when X derives from object.
Bug (or feature)?

Thomas