std::string x(x);

Question

std::string x(x);

This crashes very badly on my compiler. Does this mean I should test for this != &that in my own copy constructo

Answer 1

You should not test against code that tries to crash badly. See Null References. It says

"Just as you must assume that a non-null pointer is valid, you must assume that a reference is valid. You must have faith in your fellow programmers."

I want to complement

... you must assume that the source of a copy is valid.

If you "fix" your case, what to do for this one?

string x = string(x);