Gem::Deprecate#deprecate

# File tmp/rubies/ruby-4.1.0-preview1/lib/rubygems/deprecate.rb, line 103
def deprecate(name, repl, year, month)
  class_eval do
    old = "_deprecated_#{name}"
    alias_method old, name
    define_method name do |*args, &block|
      klass = is_a? Module
      target = klass ? "#{self}." : "#{self.class}#"
      msg = [
        "NOTE: #{target}#{name} is deprecated",
        repl == :none ? " with no replacement" : "; use #{repl} instead",
        Kernel.format(". It will be removed on or after %4d-%02d.", year, month),
        "\n#{target}#{name} called from #{Gem.location_of_caller.join(":")}",
      ]
      warn "#{msg.join}." unless Gem::Deprecate.skip
      send old, *args, &block
    end
    ruby2_keywords name
  end
end