interface Foo
{
    void foo ();
}

template FooImpl ()
{
    void foo () {}
}

class FooClass // this needs a better name
{
    mixin FooImpl;
}

interface Bar
{
    void bar ();
}

template BarImpl ()
{
    void bar () {}
}

class BarClass // this needs a better name
{
    mixin BarImpl;
}

class FooBar : Foo, Bar
{
    mixin FooImpl;
    mixin BarImpl;
    
    // since "foo" is overloaded we need to manually bring in "foo" in the
    // overload set (or what it's called)
    alias FooImpl.foo foo;
    
    void foo (int a) {}
}