diff --git a/actionpack/test/controller/redirect_test.rb b/actionpack/test/controller/redirect_test.rb
index 103ca9c77606d..efd790de634c7 100644
--- a/actionpack/test/controller/redirect_test.rb
+++ b/actionpack/test/controller/redirect_test.rb
@@ -63,7 +63,7 @@ def redirect_to_url
   end
 
   def redirect_to_url_with_unescaped_query_string
-    redirect_to "http://dev.rubyonrails.org/query?status=new"
+    redirect_to "http://example.com/query?status=new"
   end
 
   def redirect_to_url_with_complex_scheme
@@ -233,7 +233,7 @@ def test_redirect_to_url
   def test_redirect_to_url_with_unescaped_query_string
     get :redirect_to_url_with_unescaped_query_string
     assert_response :redirect
-    assert_redirected_to "http://dev.rubyonrails.org/query?status=new"
+    assert_redirected_to "http://example.com/query?status=new"
   end
 
   def test_redirect_to_url_with_complex_scheme
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index b4e29a608a5eb..79a73670c1717 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -905,8 +905,7 @@ def supports_rename_index?
       def configure_connection
         variables = @config.fetch(:variables, {}).stringify_keys
 
-        # By default, MySQL 'where id is null' selects the last inserted id.
-        # Turn this off. http://dev.rubyonrails.org/ticket/6778
+        # By default, MySQL 'where id is null' selects the last inserted id; Turn this off.
         variables['sql_auto_is_null'] = 0
 
         # Increase timeout so the server doesn't disconnect us.
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index 39308866ee138..4b819a82e8785 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -947,7 +947,6 @@ def test_find_by_id_with_conditions_with_or
     end
   end
 
-  # http://dev.rubyonrails.org/ticket/6778
   def test_find_ignores_previously_inserted_record
     Post.create!(:title => 'test', :body => 'it out')
     assert_equal [], Post.where(id: nil)
diff --git a/activerecord/test/cases/modules_test.rb b/activerecord/test/cases/modules_test.rb
index 6f65bf80eb441..7f31325f4750d 100644
--- a/activerecord/test/cases/modules_test.rb
+++ b/activerecord/test/cases/modules_test.rb
@@ -68,8 +68,7 @@ def test_assign_ids
     end
   end
 
-  # need to add an eager loading condition to force the eager loading model into
-  # the old join model, to test that. See http://dev.rubyonrails.org/ticket/9640
+  # An eager loading condition to force the eager loading model into the old join model.
   def test_eager_loading_in_modules
     clients = []