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