diff --git a/spot/tl/expansions2.cc b/spot/tl/expansions2.cc
index d80e5ffa3..96f970a94 100644
--- a/spot/tl/expansions2.cc
+++ b/spot/tl/expansions2.cc
@@ -540,7 +540,7 @@ namespace spot
         return {{f_bdd, formula::eword()}};
       }
 
-    auto rec = [&d, owner, opts, seen](formula f){
+    auto rec = [&d, owner, seen](formula f){
       return expansion2(f, d, owner, exp_opts::None, seen);
     };