expand

# File activerecord/lib/active_record/relation/predicate_builder.rb, line 35
    def self.expand(klass, table, column, value)
      queries = []

      # Find the foreign key when using queries such as:
      # Post.where(author: author)
      #
      # For polymorphic relationships, find the foreign key and type:
      # PriceEstimate.where(estimate_of: treasure)
      if klass && value.class < Base && reflection = klass.reflect_on_association(column.to_sym)
        if reflection.polymorphic?
          queries << build(table[reflection.foreign_type], value.class.base_class)
        end

        column = reflection.foreign_key
      end

      queries << build(table[column], value)
      queries
    end