module missing_header {
  module missing { header "missing_header/missing.h" }
  module error_importing_this { header "missing_header/not_missing.h" }
}

module nonrequired_missing_header {
  module unsatisfied_requires {
    requires nonexistent_feature
    header "nonrequired_missing_header/missing.h"
  }
  module fine_to_import {
    header "nonrequired_missing_header/not_missing.h"
  }
}

module missing_requirement {
  requires nonexistent_feature
  header "missing_requirement.h"
}