User id instead of quoted_id to prevent double quoting. Fixes failing test for bug #6036.

activerecord/lib/active_record/relation/predicate_builder.rb

@@ -20,7 +20,7 @@ def self.build_from_hash(engine, attributes, default_table)
           case value
           when Array, ActiveRecord::Associations::AssociationCollection, ActiveRecord::Relation
             values = value.to_a.map { |x|
-              x.respond_to?(:quoted_id) ? x.quoted_id : x
+              x.is_a?(ActiveRecord::Base) ? x.id : x
             }
             attribute.in(values)
           when Range, Arel::Relation