private List<PackageSymbol> getPackageInfoFilesFromClasses(List<? extends ClassSymbol> syms) {
        List<PackageSymbol> packages = List.nil();
        for (ClassSymbol sym : syms) {
            if (isPkgInfo(sym)) {
                packages = packages.prepend((PackageSymbol) sym.owner);
            }
        }
        return packages.reverse();
    }