1 files changed, 2 insertions, 0 deletions
diff --git a/debug.c b/debug.c
index 3b4f1cbb12..52bd0f7fb7 100644
--- a/debug.c
+++ b/debug.c
@@ -14,6 +14,7 @@
 #include <stdio.h>
 
 #include "eval_intern.h"
+#include "encindex.h"
 #include "id.h"
 #include "internal/signal.h"
 #include "ruby/encoding.h"
@@ -50,6 +51,7 @@ const union {
     enum ruby_coderange_type    enc_coderange_types;
     enum ruby_econv_flag_type   econv_flag_types;
     rb_econv_result_t           econv_result;
+    enum ruby_preserved_encindex encoding_index;
     enum ruby_robject_flags     robject_flags;
     enum ruby_robject_consts    robject_consts;
     enum ruby_rmodule_flags     rmodule_flags;