Fixed #4539 -- Fixed a subtle context resolving bug in the i18n template tag.

        return ''.join(result), vars

    def render(self, context):

        context.push()

        tmp_context = {}

        for var, val in self.extra_context.items():

            context[var] = val.render(context)

            tmp_context[var] = val.render(context)

        # Update() works like a push(), so corresponding context.pop() is at

        # the end of function

        context.update(tmp_context)

        singular, vars = self.render_token_list(self.singular)

        if self.plural and self.countervar and self.counter:

            count = self.counter.resolve(context)