where_values_hash

# File activerecord/lib/active_record/relation.rb, line 558
    def where_values_hash(relation_table_name = table_name)
      equalities = where_values.grep(Arel::Nodes::Equality).find_all { |node|
        node.left.relation.name == relation_table_name
      }

      binds = Hash[bind_values.find_all(&:first).map { |column, v| [column.name, v] }]

      Hash[equalities.map { |where|
        name = where.left.name
        [name, binds.fetch(name.to_s) {
          case where.right
          when Array then where.right.map(&:val)
          when Arel::Nodes::Casted
            where.right.val
          end
        }]
      }]
    end