Sometimes I write code like this:

    size_t i = -1;
    for ( auto const &e : some_container )
    {
        ++i;
        DoSomeProcessing(e, i);
    }

It would be nice if range-based for loops had an implicit counter
variable, so that the above code snippet could simply be written as:

    for ( auto const &e : some_container )
    {
        DoSomeProcessing(e, __i);
    }

I propose that this would work even with containers that don't allow
random access.