Support for the Ruby 2.4 series has ended. See here for reference.
IconBase
# File rss/maker/feed.rb, line 280 def to_feed(feed, current) icon = current.class::Icon.new class << icon alias_method(:url=, :content=) end set = setup_values(icon) class << icon remove_method(:url=) end if set current.icon = icon set_parent(icon, current) setup_other_elements(feed, icon) elsif variable_is_set? raise NotSetError.new("maker.item.source.icon", not_set_required_variables) end end