diff --git a/lib/rubocop/ast/traversal.rb b/lib/rubocop/ast/traversal.rb
index 7f9c48741..a50fbc18e 100644
--- a/lib/rubocop/ast/traversal.rb
+++ b/lib/rubocop/ast/traversal.rb
@@ -45,7 +45,7 @@ def on_#{type}(node)        # def on_send(node)
             end                         # end
           RUBY
           aliases.each do |m|
-            alias_method "on_#{m}", "on_#{type}"
+            alias_method :"on_#{m}", :"on_#{type}"
           end
         end