1 files changed, 4 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/module/introspection.rb b/activesupport/lib/active_support/core_ext/module/introspection.rb
index f1d26ef28f..fa692e1b0e 100644
--- a/activesupport/lib/active_support/core_ext/module/introspection.rb
+++ b/activesupport/lib/active_support/core_ext/module/introspection.rb
@@ -57,6 +57,10 @@ class Module
   end
 
   def local_constants #:nodoc:
+    ActiveSupport::Deprecation.warn(<<-MSG.squish)
+      Module#local_constants is deprecated and will be removed in Rails 5.1.
+      Use Module#constants(false) instead.
+    MSG
     constants(false)
   end
 end