Why is this ambiguity here?

Question

Consider I have the following minimal code:

#include 

template
struct TData
{
    typedef typename boost:         


        

Answer 1

I don't know what's the exact answer, but...

Because of this operator:

operator ptr_t & () { return data; }

there exist already built-in [] operator (array subscription) which accepts size_t as index. So we have two [] operators, the built-in and defined by you. Booth accepts size_t so this is considered as illegal overload probably.

//EDIT
this should work as you intended

template
struct TData
{
    ptr_t data;
    operator ptr_t & () { return data; }
};