module std {
  module vector { header "vector.h" }
  module type_traits { header "type_traits.h" }
  explicit module hash_map { header "hash_map.h" }
}

module import_self {
  module a { header "import-self-a.h" }
  module b { header "import-self-b.h" export * }
  module c { header "import-self-c.h" }
  module d { header "import-self-d.h" }
}