diff --git a/.rubocop.yml b/.rubocop.yml
index 562197300b4d4ee63c06510420f90b2dbc13434c..d14f8d6b53edb3056328289be048b039145f1d88 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -322,7 +322,7 @@ Style/MethodCallParentheses:
 
 # Checks if the method definitions have or don't have parentheses.
 Style/MethodDefParentheses:
-  Enabled: false
+  Enabled: true
 
 # Use the configured style when naming methods.
 Style/MethodName:
diff --git a/lib/gitlab/email/receiver.rb b/lib/gitlab/email/receiver.rb
index 714f45d2d4391c77165f7680d0df137bd5e9ffc3..8fc39ee46f1dde66971ce4d080dbe9096723133c 100644
--- a/lib/gitlab/email/receiver.rb
+++ b/lib/gitlab/email/receiver.rb
@@ -101,7 +101,7 @@ module Gitlab
           Project.find_with_namespace(reply_key) if reply_key
       end
 
-      def extract_reply project
+      def extract_reply(project)
         reply = ReplyParser.new(message).execute.strip
 
         raise EmptyEmailError if reply.blank?