collapse_wheres

# File activerecord/lib/active_record/relation/query_methods.rb, line 310
    def collapse_wheres(arel, wheres)
      equalities = wheres.grep(Arel::Nodes::Equality)

      arel.where(Arel::Nodes::And.new(equalities)) unless equalities.empty?

      (wheres - equalities).each do |where|
        where = Arel.sql(where) if String === where
        arel.where(Arel::Nodes::Grouping.new(where))
      end
    end