import std;

​

struct Loc

{

    string file;

    size_t line;

}

​

void foo(string file = __FILE__, size_t line = __LINE__, Loc loc = Loc(__FILE__, __LINE__))

{

    writefln!"%s vs %s"(Loc(file, line), loc);

}

​

void main()

{

    foo();

}

​