PVS-Studio warning V690 for Bitcoin

class CKey {
  ....
  // Copy constructor. This is necessary because of memlocking.
  CKey(const CKey &secret) : fValid(secret.fValid),
                             fCompressed(secret.fCompressed)
  {
    LockObject(vch);
    memcpy(vch, secret.vch, sizeof(vch));
  }
  ....
};

This suspicious code was found in Bitcoin project by PVS-Studio static code analyzer.
Warning message is:
V690 The 'CKey' class implements a copy constructor, but lacks the the '=' operator. It is dangerous to use such a class. key.h 175

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/