/// <summary>
        /// Retrieves list of packages declared in the file via 'library' statements
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        private Task <IEnumerable <IPackageInfo> > GetAllFilePackagesAsync(IRIntellisenseContext context)
        {
            var loadedPackages   = _session?.LoadedPackageNames ?? Enumerable.Empty <string>();
            var filePackageNames = context.AstRoot.GetFilePackageNames();
            var allPackageNames  = PackageIndex.PreloadedPackages.Union(filePackageNames).Union(loadedPackages);

            return(_packageIndex.GetPackagesInfoAsync(allPackageNames));
        }
        /// <summary>
        /// Retrieves list of packages declared in the file via 'library' statements
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        private Task <IEnumerable <IPackageInfo> > GetAllFilePackagesAsync(RCompletionContext context)
        {
            IEnumerable <string> loadedPackages   = _session?.LoadedPackageNames ?? Enumerable.Empty <string>();
            IEnumerable <string> filePackageNames = context.AstRoot.GetFilePackageNames();
            IEnumerable <string> allPackageNames  = PackageIndex.PreloadedPackages.Union(filePackageNames).Union(loadedPackages);

            return(_packageIndex.GetPackagesInfoAsync(allPackageNames));
        }