diff --git a/compiler/cpp/src/thrifty.yy b/compiler/cpp/src/thrifty.yy
index 1848efd..c050590 100644
--- a/compiler/cpp/src/thrifty.yy
+++ b/compiler/cpp/src/thrifty.yy
@@ -847,7 +847,7 @@
     {
       pdebug("tok_int_constant : Field -> FieldType tok_identifier");
       if ($2 < 0) {
-        pwarning(2, "No field key specified for %s, resulting protocol may have conflicts or not be backwards compatible!\n", $5);
+        pwarning(1, "No field key specified for %s, resulting protocol may have conflicts or not be backwards compatible!\n", $5);
       }
       $$ = new t_field($4, $5, $2);
       $$->set_req($3);