diff --git a/debug.c b/debug.c
index 14e1696fd4..25b233d661 100644
--- a/debug.c
+++ b/debug.c
@@ -54,11 +54,11 @@ static const union {
         RUBY_NODE_TYPESHIFT = NODE_TYPESHIFT,
         RUBY_NODE_TYPEMASK  = NODE_TYPEMASK,
         RUBY_NODE_LSHIFT    = NODE_LSHIFT,
+        RUBY_NODE_LMASK     = NODE_LMASK,
     } various;
 } dummy_gdb_enums;
 
 const VALUE RUBY_FL_USER20    = FL_USER20;
-const VALUE RUBY_NODE_LMASK = NODE_LMASK;
 
 void
 ruby_debug_print_indent(int level, int debug_level, int indent_level)