5 files changed, 15 insertions, 6 deletions
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index aeabd5b39d..a2566ae5fb 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Deprecate using `#quoted_id` in quoting.
+
+    *Ryuta Kamizono*
+
 *   Fix `wait_timeout` to configurable for mysql2 adapter.
 
     Fixes #26556.
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
diff --git a/activerecord/test/cases/quoting_test.rb b/activerecord/test/cases/quoting_test.rb
index 2541adbe72..f260d043e4 100644
--- a/activerecord/test/cases/quoting_test.rb
+++ b/activerecord/test/cases/quoting_test.rb
@@ -82,7 +82,7 @@ module ActiveRecord
       end
 
       def test_quote_with_quoted_id
-        assert_equal 1, @quoter.quote(Struct.new(:quoted_id).new(1))
+        assert_deprecated { assert_equal 1, @quoter.quote(Struct.new(:quoted_id).new(1)) }
       end
 
       def test_quote_nil
diff --git a/activerecord/test/cases/sanitize_test.rb b/activerecord/test/cases/sanitize_test.rb
index 23bcb0af1e..72f09186e2 100644
--- a/activerecord/test/cases/sanitize_test.rb
+++ b/activerecord/test/cases/sanitize_test.rb
@@ -152,11 +152,15 @@ class SanitizeTest < ActiveRecord::TestCase
   end
 
   def test_bind_record
-    o = Struct.new(:quoted_id).new(1)
-    assert_equal "1", bind("?", o)
+    o = Class.new {
+      def quoted_id
+        1
+      end
+    }.new
+    assert_deprecated { assert_equal "1", bind("?", o) }
 
     os = [o] * 3
-    assert_equal "1,1,1", bind("?", os)
+    assert_deprecated { assert_equal "1,1,1", bind("?", os) }
   end
 
   def test_named_bind_with_postgresql_type_casts