main.cpp: In function ‘int main()’:
main.cpp:61:24: error: no match for ‘operator<<’ (operand types are ‘Message’ and ‘<unresolved overloaded function type>’)
     m << a << "-" << b << endl;
                        ^
main.cpp:61:24: note: candidates are:
main.cpp:37:14: note: Message& Message::operator<<(const MyTypeA&)
     Message& operator <<(const MyTypeA &a) {
              ^
main.cpp:37:14: note:   no known conversion for argument 1 from ‘<unresolved overloaded function type>’ to ‘const MyTypeA&’
main.cpp:42:14: note: Message& Message::operator<<(const MyTypeB&)
     Message& operator <<(const MyTypeB &b) {
              ^
main.cpp:42:14: note:   no known conversion for argument 1 from ‘<unresolved overloaded function type>’ to ‘const MyTypeB&’
main.cpp:48:14: note: template<class T> Message& Message::operator<<(const T&)
     Message& operator <<(const T &t)
              ^
main.cpp:48:14: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   couldn't deduce template parameter ‘T’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/string:52:0,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ios:42,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:38,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/bits/basic_string.h:2753:5: note: template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&)
     operator<<(basic_ostream<_CharT, _Traits>& __os,
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/bits/basic_string.h:2753:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   couldn't deduce template parameter ‘_Alloc’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:471:5: note: std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, _CharT) [with _CharT = char; _Traits = std::char_traits<char>]
     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:471:5: note:   no known conversion for argument 2 from ‘<unresolved overloaded function type>’ to ‘char’
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:476:5: note: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, char)
     operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:476:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘char’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:482:5: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, char)
     operator<<(basic_ostream<char, _Traits>& __out, char __c)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:482:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘char’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:488:5: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, signed char)
     operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:488:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘signed char’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:493:5: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, unsigned char)
     operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:493:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘unsigned char’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:513:5: note: std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const _CharT*) [with _CharT = char; _Traits = std::char_traits<char>]
     operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:513:5: note:   no known conversion for argument 2 from ‘<unresolved overloaded function type>’ to ‘const char*’
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:609:0,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/bits/ostream.tcc:321:5: note: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const char*)
     operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/bits/ostream.tcc:321:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘const char*’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:530:5: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const char*)
     operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:530:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘const char*’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:543:5: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const signed char*)
     operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:543:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘const signed char*’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:548:5: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const unsigned char*)
     operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:548:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   cannot convert ‘std::endl’ (type ‘<unresolved overloaded function type>’) to type ‘const unsigned char*’
     m << a << "-" << b << endl;
                           ^
In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/iostream:39:0,
                 from main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:602:5: note: template<class _CharT, class _Traits, class _Tp> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&&, const _Tp&)
     operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x)
     ^
/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4/ostream:602:5: note:   template argument deduction/substitution failed:
main.cpp:61:27: note:   couldn't deduce template parameter ‘_Tp’
     m << a << "-" << b << endl;
                           ^