const_warning

# File lib/rake/application.rb, line 575
    def const_warning(const_name)
      @const_warning ||= false
      if ! @const_warning
        $stderr.puts %{WARNING: Deprecated reference to top-level constant '#{const_name}' } +
          %{found at: #{rakefile_location}} # '
        $stderr.puts %{    Use --classic-namespace on rake command}
        $stderr.puts %{    or 'require "rake/classic_namespace"' in Rakefile}
      end
      @const_warning = true
    end