Re: implicit operator[] member functions?

[Marc Glisse <marc dot glisse at inria dot fr>]

On Fri, 18 Jan 2013, John Boncek wrote:

> Using gcc 4.4.3 (Ubuntu 4.4.3-4ubuntu5), I have a C++ class CFoo that doesn't
> define an operator[] member function and has no base classes.  But use of []
> is allowed by the compiler, like this:
>
> CFoo  foo;
> CFoo  test;
> test = foo[0];
> foo[0] = 0;
>
> Both assignment statements seem illegal to me but cause no errors.  I cannot
> post the class itself because it contains sensitive information.

If you reduce the example, it will both lose the sensitive information and 
become easier to understand for everyone, clearly worth it!

> Can anyone explain what's going on here?  Specifically, is this a 
> compiler bug, or are implicit operator[] member functions sometimes 
> generated by the compiler and under what rules?  Thanks for your 
> attention.

Is your class convertible to anything? Does it have a base class?

--
Marc Glisse