[shhsshs]

Totally achievable by using interfaces instead of structs

    type Foo interface {
      Foo() int
    }

    type Bar interface {
      Bar() string
    }

    type FooBar interface {
      Foo
      Bar
    }

Then functions that accept a Foo will also happily take a FooBar. Does not solve the problem of passing a FooBar[] to a function that expects Foo[] but that can be solved with generics or a simple function to convert FooBar[] to Foo[].