# File lib/rake.rb, line 291
291:     def dup
292:       sibling = self.class.new
293:       instance_variables.each do |ivar|
294:         value = self.instance_variable_get(ivar)
295:         new_value = value.clone rescue value
296:         sibling.instance_variable_set(ivar, new_value)
297:       end
298:       sibling.taint if tainted?
299:       sibling
300:     end