class Bundler::Resolver

def verify_gemfile_dependencies_are_found!(requirements)
  requirements.each do |requirement|
    next if requirement.name == 'bundler'
    if search_for(requirement).empty?
      if base = @base[requirement.name] and !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}`"
      elsif requirement.source
        name = requirement.name
        versions = @source_requirements[name][name].map { |s| s.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}' "
        if @index.source_types.include?(Bundler::Source::Rubygems)
          message << "in any of the gem sources listed in your Gemfile."
        else
          message << "in the gems available on this machine."
        end
      end
      raise GemNotFound, message
    end
  end
end