Why can't redefine type names in class in C++?

Question

According to the book C++ Primer section, 7.4.1 Type Names Are Special:

Ordinarily, an inner scope can redefine a name from an outer scope even if tha

Answer 1

When the compiler reads the line

    Money balance() { return bal; }

in the class definition, it already uses the definition of Money outside the class. That makes the line

    typedef double Money;

inside the class a problem. However, you may use redefine Money inside the class before it is used in the class. The following is OK.

typedef double Money;

class Account {
    public:
        typedef double Money;
        Money balance() { return bal; }
    private:
        Money bal;
};

The key point in the quote is:

hence the class may not subsequently redefine that name.