class Rake::Application

def deprecate(old_usage, new_usage, call_site)


Rake.application.deprecate("import", "Rake.import", caller.first)
Example:

Warn about deprecated usage. 
def deprecate(old_usage, new_usage, call_site)
  fail "GONE"
  return if options.ignore_deprecate
  $stderr.puts "WARNING: '#{old_usage}' is deprecated.  " +
    "Please use '#{new_usage}' instead.\n" +
    "    at #{call_site}"
end