[kovidgoyal]

sphinx is pretty fragile, you need to patch docutils to ignore that error. My docutils has:

def dupname(node, name):
    node['dupnames'].append(name)
    try:
        node['names'].remove(name)
    except ValueError:
        pass
    # Assume that this method is referenced, even though it isn't; we
    # don't want to throw unnecessary system_messages.
    node.referenced = 1