I don't know if this would be considered a bug in the code or in the documentation.

The documentation clearly states:
Q_CHECK_PTR does nothing if QT_NO_DEBUG was defined during compilation.

However, if QT_NO_EXCEPTIONS is not set, the above statement is not true. It actually calls qBadAlloc which throws a std::bad_alloc exception. At the very least, this should be noted in the documentation.