2 files changed, 3 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
index a99b58f41c..e5a24b2aca 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -10,6 +10,8 @@ module ActiveRecord
         value = id_value_for_database(value) if value.is_a?(Base)
 
         if value.respond_to?(:quoted_id)
+          ActiveSupport::Deprecation.warn \
+            "Using #quoted_id is deprecated and will be removed in Rails 5.2."
           return value.quoted_id
         end
 
diff --git a/activerecord/lib/active_record/sanitization.rb b/activerecord/lib/active_record/sanitization.rb
index 427c0019c6..64bda1539c 100644
--- a/activerecord/lib/active_record/sanitization.rb
+++ b/activerecord/lib/active_record/sanitization.rb
@@ -1,4 +1,3 @@
-
 module ActiveRecord
   module Sanitization
     extend ActiveSupport::Concern
@@ -207,9 +206,9 @@ module ActiveRecord
         end
     end
 
-    # TODO: Deprecate this
     def quoted_id # :nodoc:
       self.class.connection.quote(@attributes[self.class.primary_key].value_for_database)
     end
+    deprecate :quoted_id
   end
 end