2 files changed, 1 insertions, 16 deletions
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index b54a167dc3..f1ac421a50 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -318,8 +318,7 @@ module ActiveRecord
     def find_one(id)
       id = id.id if ActiveRecord::Base === id
 
-      if IdentityMap.enabled? &&
-        (where_values.blank? || contains_only_subclass_constraint?(where_values)) &&
+      if IdentityMap.enabled? && where_values.blank? &&
         limit_value.blank? && order_values.blank? &&
         includes_values.blank? && preload_values.blank? &&
         readonly_value.nil? && joins_values.blank? &&
@@ -395,11 +394,5 @@ module ActiveRecord
     def using_limitable_reflections?(reflections)
       reflections.none? { |r| r.collection? }
     end
-    
-    def contains_only_subclass_constraint?(where_values)
-      where_values.length == 1 &&
-      !where_values[0].left.nil? && where_values[0].left.relation.name == table_name &&
-      !where_values[0].right.nil? && where_values[0].right.length == 1 && where_values[0].right[0] == @klass.name
-    end
   end
 end
diff --git a/activerecord/test/cases/identity_map_test.rb b/activerecord/test/cases/identity_map_test.rb
index 0d031d433c..3efc8bf559 100644
--- a/activerecord/test/cases/identity_map_test.rb
+++ b/activerecord/test/cases/identity_map_test.rb
@@ -162,14 +162,6 @@ class IdentityMapTest < ActiveRecord::TestCase
     c2 = Comment.find(c.id)
     assert_same(c1, c2)
   end
-  
-  def test_queries_are_not_executed_when_finding_inherited_class_by_id
-    c = comments(:sub_special_comment)
-    SubSpecialComment.find(c.id)
-    assert_no_queries do
-      SubSpecialComment.find(c.id)
-    end
-  end
 
   ##############################################################################
   # Tests checking dirty attribute behavior with IM                            #