final List<T> identifiables = new ArrayList<>(recessive.size());

        for (T identifiable : recessive) {
            if (!dominantById.containsKey(identifiable.getId())) {
                identifiable.setSourceLevel(recessiveSourceLevel);

                identifiables.add(identifiable);
            }
        }

        dominant.addAll(0, identifiables);
    }

        // with multiple local repository implementations yet.
        artifact.setFile(artifactFile);

        return artifact;
    }

    @Override
    public String getId() {
        return localRepository.getId();
    }

    @Override
    public String pathOfLocalRepositoryMetadata(ArtifactMetadata metadata, ArtifactRepository repository) {

  interface Base {
    CharSequence getId();
  }

  interface Sub extends Base {
    @Override
    String getId();
  }

  private static class ForwardingSub implements Sub {
    private final Sub delegate;

    ForwardingSub(Sub delegate) {
      this.delegate = delegate;
    }

    @Override
    public String getId() {
      return delegate.getId();
    }

    @Override

    @Override
    public String id() {
        return lifecycleOverlay.getId();
    }

    @Override
    public Collection<Phase> phases() {
        return lifecycleOverlay.getPhases().stream()
                .map(phase -> new Phase() {
                    @Override
                    public String name() {
                        return phase.getId();
                    }

                    @Override

        this.artifact = artifact;
    }

    private static String constructMessage(MavenProject project, Artifact artifact) {
        return DEFAULT_MESSAGE + " (project: " + project.getId() + "; illegal attachment: " + artifact.getId() + ")";
    }

    public MavenProject getProject() {
        return project;
    }

    public Artifact getArtifact() {
        return artifact;
    }

    private final CoreExtension extension;

    public ExtensionResolutionException(CoreExtension extension, Throwable cause) {
        super(
                "Extension " + extension.getId() + " or one of its dependencies could not be resolved: "
                        + cause.getMessage(),
                cause);
        this.extension = extension;
    }

    /**

                && a1.isOptional() == a2.isOptional();
    }

    private static int repositoryHashCode(ArtifactRepository repository) {
        int result = 17;
        result = 31 * result + (repository.getId() != null ? repository.getId().hashCode() : 0);
        return result;
    }

    private static int repositoriesHashCode(List<ArtifactRepository> repositories) {
        int result = 17;

  interface Base {
    CharSequence getId();
  }

  interface Sub extends Base {
    @Override
    String getId();
  }

  private static class ForwardingSub implements Sub {
    private final Sub delegate;

    ForwardingSub(Sub delegate) {
      this.delegate = delegate;
    }

    @Override
    public String getId() {
      return delegate.getId();
    }

    @Override

        return userLocalArtifactRepository.pathOfLocalRepositoryMetadata(metadata, repository);
    }

    @Override
    public String getId() {
        return userLocalArtifactRepository.getId();
    }

    @Override
    public String pathOf(Artifact artifact) {
        return userLocalArtifactRepository.pathOf(artifact);
    }

    @Override

                context.logger.warn(
                        "* " + extension.getId() + " configured in " + formatLocation(extension.getLocation("")));
            }
        }

        context.logger.debug("Selected core extensions (in loading order):");
        for (CoreExtension source : selectedExtensions.values()) {
            context.logger.debug("* " + source.getId() + ": " + formatLocation(source.getLocation("")));
        }