Gem::Commands::SetupCommand#uninstall_old_gemcutter

# File tmp/rubies/ruby-4.0.0/lib/rubygems/commands/setup_command.rb, line 570
def uninstall_old_gemcutter
  require_relative "../uninstaller"

  ui = Gem::Uninstaller.new("gemcutter", all: true, ignore: true,
                                         version: "< 0.4")
  ui.uninstall
rescue Gem::InstallError
end