diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 68f275e9a295..aa14d56cf923 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -15900,6 +15900,7 @@ with pkgs;
     polyml = polyml.overrideAttrs {
       pname = "polyml-for-isabelle";
       version = "2025";
+      __intentionallyOverridingVersion = true; # avoid a warning, no src override
       configureFlags = [
         "--enable-intinf-as-int"
         "--with-gmp"