diff --git a/lib/debug/session.rb b/lib/debug/session.rb
index 6a838eec0..191b4e4fd 100644
--- a/lib/debug/session.rb
+++ b/lib/debug/session.rb
@@ -2538,7 +2538,7 @@ def trap sig, *command, &command_proc
           sig
         end
 
-      case sig&.to_s&.to_sym
+      case sym
       when :INT, :SIGINT
         if defined?(SESSION) && SESSION.active? && SESSION.intercept_trap_sigint?
           return SESSION.save_int_trap(command.empty? ? command_proc : command.first)