Re: Typedef allows redefinition of names?

I was a bit surprised to find that my compiler (MSVC++) actually
accepts the following as legal. It cleans up the code very nicely,
but I am sort of confused about some of the finer points of how the
naming and template systems interact in a compiler. Does the
following always work?

In Vector3.h, I have this class

namespace Geometry {

termplate<typename NumericType>
class Vector3
{
...
};

}

In another file, Triangle.h, I have

#include <Vector3.h>

namespace Geometry {

template<typename NumericType>
class Triangle
{
public:
    typedef Vector3<NumericType> Vector3;

   //Then I go on to use Vector3 instead of Vector3<NumericType>
};

}

Like I said, I was pretty surprised it let me take the "root" part of
the template name Vector3<NumericType> and redefine it as a specific
type, namely the specific type that inherits the template type from
the class that it belongs to. Needless to say, if I type in
Vector3<NumericType> after the typedef this produces an error, since
the symbol Vector3 = Vector3<NumericType> already.