diff --git a/activerecord/lib/active_record/type_caster.rb b/activerecord/lib/active_record/type_caster.rb
index 63ba10c28936ccbb34c11b00cdb55c3c60523ad8..accc339d002851b91d8c2e68ee7f27ec645497d4 100644
--- a/activerecord/lib/active_record/type_caster.rb
+++ b/activerecord/lib/active_record/type_caster.rb
@@ -2,6 +2,6 @@
 require 'active_record/type_caster/connection'
 
 module ActiveRecord
-  module TypeCaster
+  module TypeCaster # :nodoc:
   end
 end
diff --git a/activerecord/lib/active_record/type_caster/connection.rb b/activerecord/lib/active_record/type_caster/connection.rb
index 868d08ed449342540505155c305e5f43db17d1e3..7ed8dcc313dded9978602f26e4dad888b2338db5 100644
--- a/activerecord/lib/active_record/type_caster/connection.rb
+++ b/activerecord/lib/active_record/type_caster/connection.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module TypeCaster
-    class Connection
+    class Connection # :nodoc:
       def initialize(klass, table_name)
         @klass = klass
         @table_name = table_name
diff --git a/activerecord/lib/active_record/type_caster/map.rb b/activerecord/lib/active_record/type_caster/map.rb
index 4b1941351c2df48c6202c9f7c845039bebd2f67c..3a367b3999cd73290716d84cefc1037a79f787e6 100644
--- a/activerecord/lib/active_record/type_caster/map.rb
+++ b/activerecord/lib/active_record/type_caster/map.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module TypeCaster
-    class Map
+    class Map # :nodoc:
       def initialize(types)
         @types = types
       end