C++: Convenient way to access operator[] from within class?

(*this)[bar];

works fine for me.

Use

(*this)[bar]

to call the operator[] of the instance object.

Assuming bar is an integer (or can be auto-converted to one), this[bar] treats the this pointer as an array and indexes the bar-th element of that array. Unless this is in an array, this will result in undefined behavior. If bar isn't integer-like, expect a compile-time error.