Empty declarator error when cythoning a class?

I am trying to compile the following .pyx file using Cython:

import collections

nil = object()  # used to distinguish from None

class TrieNode(object):
    __slots__ = ['char', 'output', 'fail', 'children']
    def __init__(self, char):
        self.char = char
        self.output = nil
        self.fail = nil
        self.children = {}

    def __repr__(self):
        if self.output is not nil:
            return "<TrieNode '%s' '%s'>" % (self.char, self.output)
        else:
            return "<TrieNode '%s'>" % self.char

And Cython throws this error:

running build_ext
cythoning TrieNode.pyx to TrieNode.c

Error compiling Cython file:
------------------------------------------------------------
...

nil = object()  # used to distinguish from None

class TrieNode(object):
        __slots__ = ['char', 'output', 'fail', 'children']
        def __init__(self, char):
                       ^
------------------------------------------------------------

TrieNode.pyx:7:24: Empty declarator

building 'TrieNode' extension
C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\BIN\amd64\cl.exe /c /nologo /Ox /MD /W3 /GS- /DNDEBUG -IE:\Python26\include -IE:\Python26\PC /Tc
TrieNode.c /Fobuild\temp.win-amd64-2.6\Release\TrieNode.obj
TrieNode.c
TrieNode.c(1) : fatal error C1189: #error :  Do not use this file, it is the result of a failed Cython compilation.
error: command 'cl.exe' failed with exit status 2

My setup.py currently looks like this:

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(
    cmdclass = {'build_ext': build_ext},
    ext_modules = [Extension("TrieNode", ["TrieNode.pyx"])]
)

I saw an example where a Python class was compiled to a Cython file without problems but this one does not seem to be working. Can someone tell me what I am missing?

In your __init__ method, you have a variable named char. If you Cythonize a .py module this is fine. However, in a Cython .pyx file, even Python def functions can have C type declarations in the parameters.