polymorphic_base_class_from_value

# File activerecord/lib/active_record/relation/predicate_builder.rb, line 79
    def self.polymorphic_base_class_from_value(value)
      case value
      when Relation
        value.klass.base_class
      when Array
        val = value.compact.first
        val.class.base_class if val.is_a?(Base)
      when Base
        value.class.base_class
      end
    end