import std.stdio;

​

struct Foo

{

    private int _foo;

    this(int i)

    {

        _foo = i;

    }

    @property foo() { return _foo; }

    auto opBinary(string op)(const Foo rhs) const

    {

        static if (op == "+") return Foo(_foo + rhs._foo);

        else static if (op == "-") return Foo(_foo - rhs._foo);

        else static assert(0, "Operator "~op~" not implemented");

    }

}

​

struct Bar

{

    Foo f;

    alias f this;

    this(Foo f)

    {

        this.f = f;

    }

}

​

void main(string[] args)

{

    // How to help (or make) compiler to deduce that v5 is Bar type?

    auto v5 = Bar(Foo(2)) + Bar(Foo(3));

    pragma(msg, typeof(v5));

    writefln("v5 = %s", v5);

}