diff --git a/src/ltlvisit/simplify.cc b/src/ltlvisit/simplify.cc
index 46aeb7d62..d3fa5d077 100644
--- a/src/ltlvisit/simplify.cc
+++ b/src/ltlvisit/simplify.cc
@@ -1826,7 +1826,7 @@ namespace spot
 		  if (c_->implication_neg(b, a, true))
 		    {
 		      a->destroy();
-		      result_ = unop::instance(unop::G, b);
+		      result_ = recurse_destroy(unop::instance(unop::G, b));
 		      return;
 		    }
 		  if (b->kind() == formula::BinOp)