overload2.cpp:9:21: error: call to deleted function 'f'
    f( a ), f( b ), f( c );
                    ^
overload2.cpp:5:6: note: candidate function [with T = long]
    has been explicitly deleted
void f( T ) = delete;
     ^
overload2.cpp:2:6: note: candidate function
void f( int ) { std::cout << "int, "; }
     ^
...