Extensions to nil which allow for more helpful error messages for people who are new to rails.

The aim is to ensure that when users pass nil to methods where that isn’t appropriate, instead of NoMethodError and the name of some method used by the framework users will see a message explaining what type of object was expected.

Methods
I
T
Constants
WHINERS = [ ::ActiveRecord::Base, ::Array ]
 
Instance Public methods
id()

Source: show 

# File rails/activesupport/lib/active_support/whiny_nil.rb, line 21
def id
  raise RuntimeError, "Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id", caller
end
to_param()

Source: show 

# File rails/actionpack/lib/action_controller/routing.rb, line 22
def to_param
  self
end