4 files changed, 24 insertions, 3 deletions
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 1250f8a3c3..475a298467 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -275,7 +275,7 @@ module ActiveRecord
       def relation # :nodoc:
         relation = Relation.create(self, arel_table, predicate_builder)
 
-        if finder_needs_type_condition?
+        if finder_needs_type_condition? && !ignore_default_scope?
           relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
         else
           relation
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
index cdcb73382f..8baf3b8044 100644
--- a/activerecord/lib/active_record/scoping/default.rb
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -122,11 +122,11 @@ module ActiveRecord
         end
 
         def ignore_default_scope? # :nodoc:
-          ScopeRegistry.value_for(:ignore_default_scope, self)
+          ScopeRegistry.value_for(:ignore_default_scope, base_class)
         end
 
         def ignore_default_scope=(ignore) # :nodoc:
-          ScopeRegistry.set_value_for(:ignore_default_scope, self, ignore)
+          ScopeRegistry.set_value_for(:ignore_default_scope, base_class, ignore)
         end
 
         # The ignore_default_scope flag is used to prevent an infinite recursion
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
index 86316ab476..ad5ca70f36 100644
--- a/activerecord/test/cases/scoping/default_scoping_test.rb
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -459,4 +459,18 @@ class DefaultScopingTest < ActiveRecord::TestCase
     scope = Bus.all
     assert_equal scope.where_clause.ast.children.length, 1
   end
+
+  def test_sti_conditions_are_not_carried_in_default_scope
+    ConditionalStiPost.create! body: ''
+    SubConditionalStiPost.create! body: ''
+    SubConditionalStiPost.create! title: 'Hello world', body: ''
+
+    assert_equal 2, ConditionalStiPost.count
+    assert_equal 2, ConditionalStiPost.all.to_a.size
+    assert_equal 3, ConditionalStiPost.unscope(where: :title).to_a.size
+
+    assert_equal 1, SubConditionalStiPost.count
+    assert_equal 1, SubConditionalStiPost.all.to_a.size
+    assert_equal 2, SubConditionalStiPost.unscope(where: :title).to_a.size
+  end
 end
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index 23cebe2602..bf3079a1df 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -263,3 +263,10 @@ end
 class SerializedPost < ActiveRecord::Base
   serialize :title
 end
+
+class ConditionalStiPost < Post
+  default_scope { where(title: 'Untitled') }
+end
+
+class SubConditionalStiPost < ConditionalStiPost
+end