↓これ、Borland-C++5.5.1でエラー出ませんけど？

#include <string>
#define TCHAR char

class A{
std::basic_string<TCHAR> s_;
public:
A(std::basic_string<TCHAR>& ref) : s_(ref) { }
};

std::basic_string<TCHAR> str;
A a(str);

main()
{}