class ActiveRecord::Reflection::ThroughReflection

def source_reflection


# =>
tags_reflection.source_reflection
tags_reflection = Post.reflect_on_association(:tags)

end
belongs_to :tag
belongs_to :post
class Tagging < ActiveRecord::Base

end
has_many :tags, through: :taggings
has_many :taggings
class Post < ActiveRecord::Base

and pluralized form for :belongs_to or :has_many.
Returns the source of the through reflection. It checks both a singularized
def source_reflection
  through_reflection.klass._reflect_on_association(source_reflection_name)
end