Some objects are dupable, some are not. So we define a version of dup (called rake_dup) that returns self on the handful of classes that are not dupable.

Methods
Public Instance methods
rake_dup()

Duplicate an object if it can be duplicated. If it can not be cloned or duplicated, then just return the original object.

    # File lib/rake.rb, line 49
49:   def rake_dup()
50:     dup
51:   end