check_validity!

# File activerecord/lib/active_record/reflection.rb, line 568
      def check_validity!
        check_validity_of_inverse!

        if !polymorphic? && (klass.composite_primary_key? || active_record.composite_primary_key?)
          if (has_one? || collection?) && Array(active_record_primary_key).length != Array(foreign_key).length
            raise CompositePrimaryKeyMismatchError.new(self)
          elsif belongs_to? && Array(association_primary_key).length != Array(foreign_key).length
            raise CompositePrimaryKeyMismatchError.new(self)
          end
        end
      end