1 files changed, 1 insertions, 0 deletions
diff --git a/vm_core.h b/vm_core.h
index 7bf971b9a5..e828e917ba 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -430,6 +430,7 @@ typedef struct rb_vm_struct {
     struct RArray at_exit;
 
     VALUE *defined_strings;
+    st_table *frozen_strings;
 
     /* params */
     struct { /* size in byte */