class Bundler::Resolver

def verify_gemfile_dependencies_are_found!(requirements)
  requirements.each do |requirement|
    next if requirement.name == "bundler"
    next unless search_for(requirement).empty?
    if (base = @base[requirement.name]) && !base.empty?
      version = base.first.version
      message = "You have requested:\n" \
        "  #{requirement.name} #{requirement.requirement}\n\n" \
        "The bundle currently has #{requirement.name} locked at #{version}.\n" \
        "Try running `bundle update #{requirement.name}`\n\n" \
        "If you are updating multiple gems in your Gemfile at once,\n" \
        "try passing them all to `bundle update`"
    elsif requirement.source
      name = requirement.name
      versions = @source_requirements[name][name].map(&:version)
      message  = "Could not find gem '#{requirement}' in #{requirement.source}.\n"
      if versions.any?
        message << "Source contains '#{name}' at: #{versions.join(", ")}"
      else
        message << "Source does not contain any versions of '#{requirement}'"
      end
    else
      message = "Could not find gem '#{requirement}' in any of the gem sources " \
        "listed in your Gemfile or available on this machine."
    end
    raise GemNotFound, message
  end
end