using 'self' in the closure of extension type methods is broken

[scoder]

The following fails at runtime:

@cython.cclass
class ExtType(object):
    def const1(self):
        return 1

    def ext_method(self, a=2):
        """
        >>> x = ExtType()
        >>> x.ext_method()()
        (1, 2)
        >>> x.ext_method(3)()
        (1, 3)
        """
        def func():
            return self.const1(), a
        return func

The error message is:

NameError: free variable 'self' referenced before assignment in enclosing scope

The problem is that the 'self' field is not being set in the closure instance. The same issue leads to crashes for generator methods.

[scoder]

Fixed here:

 https://github.com/cython/cython/commit/695dc278c661ba759394aa1676a4201407e07e3e