diff --git a/js/src/jspubtd.h b/js/src/jspubtd.h
index 8aa5bc779ef6..3f06c37f2806 100644
--- a/js/src/jspubtd.h
+++ b/js/src/jspubtd.h
@@ -231,7 +231,7 @@ typedef void
 
 typedef struct JSErrorFormatString {
     const char *format;
-    const uintN argCount;
+    uintN argCount;
 } JSErrorFormatString;
 
 typedef const JSErrorFormatString *