I find that making a class non-copyable helps me a lot with my code quality. Initially I did this with boost::noncopyable, but I found the VC++ compiler errors to be not as helpful as with private members (double clicking lead to the wrong place in the code).
T(T const&);
T& operator=(T const&);
Indeed, it has alerted me to quite a few cases were classes were not passed as reference where they should have. So much so, that I would very much like to get a warning even on classes that I just need to copy construct once.
Is there a good way to do this? I was thinking for example of leaving above two methods private and adding a public T(T const&,bool dummy) constructor to call when I really want to copy construct. Or maybe alternatively make above two methods public and somehow activate a compiler warning when copy constructing, suppressing the warning where I do want to.
Or maybe there is an all together better way?
Not sure if it's exactly what you want, but if you mark the copy constructor explicit then the class can't be passed by value or copy-initialized, but you can copy-construct using direct initialization.
You'd presumably want to keep the assignment operator private, maybe a NonAssignable base would be useful for that.