diff --git a/compiler/cpp/src/parse/t_field.h b/compiler/cpp/src/parse/t_field.h
index ac10d57..7bbcc0f 100644
--- a/compiler/cpp/src/parse/t_field.h
+++ b/compiler/cpp/src/parse/t_field.h
@@ -155,7 +155,7 @@
  * not it was specified by the user or automatically chosen.
  */
 struct t_field_id {
-  int64_t value;
+  int32_t value;
   bool auto_assigned;
 };