diff --git a/dev-ml/core/core-0.15.1-r2.ebuild b/dev-ml/core/core-0.15.1-r2.ebuild
index 0099117c1a0bf..e35a27104a0d6 100644
--- a/dev-ml/core/core-0.15.1-r2.ebuild
+++ b/dev-ml/core/core-0.15.1-r2.ebuild
@@ -38,7 +38,7 @@ RDEPEND="
 	dev-ml/ppx_pipebang:=
 	dev-ml/ppx_sexp_message:=
 	dev-ml/ppx_sexp_value:=
-	dev-ml/ppx_stable:=
+	dev-ml/ppx_stable:${SLOT}[ocamlopt?]
 	dev-ml/ppx_string:${SLOT}[ocamlopt?]
 	dev-ml/ppx_ignore_instrumentation:${SLOT}[ocamlopt?]
 	dev-ml/typerep:${SLOT}[ocamlopt?]