Accessing static variables from static methods

[Matthew White]

Using Stata 13.1 SE on Windows 7, I'm having trouble with Mata classes: I can't seem to access static variables from static methods. For example, the following does not compile:

mata:

class example {
    public:
        static real scalar increment()

    private:
        static real scalar count
}

real scalar example::increment()
{
    if (count == .)
        count = 0
    return(++count)
}

end

I receive the error "variable count undeclared". However, when I make test::increment() not static by removing the underlined word, it compiles. Am I doing something wrong? Shouldn't static methods be able to access static variables?