The code is as follow:

std::basic_string<TCHAR> dest;
std::string source;

source = makesource(); //return a std::string value

#ifdef QT_DLL
dest = QString(source.c_str()).toStdWString(); //debug assertion failed here
#endif

When I build the project in release mode, everything is OK, but when I build in debug mode, the program crashed at the second line from the bottom.

Any suggestion will be appreciated.
Thank you for your time.