package foo:foo;

interface foo {
  type headers = list<tuple<string, string>>;
  record a {
    headers: headers
  }
  x: func() -> a;
}

interface bar {
  use foo.{a};
  x: func() -> a;
}

world baz {
  import foo;
  import bar;
  import baz: interface {
    use foo.{a};
    x: func() -> a;
  }
}