private async Task <ResolvedReferences> ResolveReferencesAsync(ProjectId id, ProjectFileInfo projectFileInfo, CommandLineArguments commandLineArgs, CancellationToken cancellationToken)
            {
                // First, gather all of the metadata references from the command-line arguments.
                var resolvedMetadataReferences = commandLineArgs.ResolveMetadataReferences(
                    new WorkspaceMetadataFileReferenceResolver(
                        metadataService: GetWorkspaceService <IMetadataService>(),
                        pathResolver: new RelativePathResolver(commandLineArgs.ReferencePaths, commandLineArgs.BaseDirectory)));

                var builder = new ResolvedReferencesBuilder(resolvedMetadataReferences);

                var projectDirectory = Path.GetDirectoryName(projectFileInfo.FilePath);

                // Next, iterate through all project references in the file and create project references.
                foreach (var projectFileReference in projectFileInfo.ProjectReferences)
                {
                    var aliases = projectFileReference.Aliases;

                    if (_pathResolver.TryGetAbsoluteProjectPath(projectFileReference.Path, baseDirectory: projectDirectory, _discoveredProjectOptions.OnPathFailure, out var projectReferencePath))
                    {
                        // The easiest case is to add a reference to a project we already know about.
                        if (TryAddReferenceToKnownProject(id, projectReferencePath, aliases, builder))
                        {
                            continue;
                        }

                        // If we don't know how to load a project (that is, it's not a language we support), we can still
                        // attempt to verify that its output exists on disk and is included in our set of metadata references.
                        // If it is, we'll just leave it in place.
                        if (!IsProjectLoadable(projectReferencePath) &&
                            await VerifyUnloadableProjectOutputExistsAsync(projectReferencePath, builder, cancellationToken).ConfigureAwait(false))
                        {
                            continue;
                        }

                        // If metadata is preferred, see if the project reference's output exists on disk and is included
                        // in our metadata references. If it is, don't create a project reference; we'll just use the metadata.
                        if (_preferMetadataForReferencesOfDiscoveredProjects &&
                            await VerifyProjectOutputExistsAsync(projectReferencePath, builder, cancellationToken).ConfigureAwait(false))
                        {
                            continue;
                        }

                        // Finally, we'll try to load and reference the project.
                        if (await TryLoadAndAddReferenceAsync(id, projectReferencePath, aliases, builder, cancellationToken).ConfigureAwait(false))
                        {
                            continue;
                        }
                    }

                    // We weren't able to handle this project reference, so add it without further processing.
                    var unknownProjectId    = _projectMap.GetOrCreateProjectId(projectFileReference.Path);
                    var newProjectReference = CreateProjectReference(from: id, to: unknownProjectId, aliases);
                    builder.AddProjectReference(newProjectReference);
                }

                return(builder.ToResolvedReferences());
            }
        private static ResolvedReferences ResolveReferencesAsync(ProjectId id, ProjectFileInfo projectFileInfo, CommandLineArguments commandLineArgs)
        {
            // First, gather all of the metadata references from the command-line arguments.
            var resolvedMetadataReferences = commandLineArgs.ResolveMetadataReferences(
                new WorkspaceMetadataFileReferenceResolver(
                    metadataService: _metadataService,
                    pathResolver: new RelativePathResolver(commandLineArgs.ReferencePaths, commandLineArgs.BaseDirectory)));

            var builder = new ResolvedReferencesBuilder(resolvedMetadataReferences);

            var projectDirectory = Path.GetDirectoryName(projectFileInfo.FilePath);

            return(builder.ToResolvedReferences());
        }