diff --git a/libguile/lightening/lightening/lightening.c b/libguile/lightening/lightening/lightening.c
index 340987683..14c8426cb 100644
--- a/libguile/lightening/lightening/lightening.c
+++ b/libguile/lightening/lightening/lightening.c
@@ -206,6 +206,7 @@ jit_destroy_state(jit_state_t *_jit)
 jit_pointer_t
 jit_address(jit_state_t *_jit)
 {
+  ASSERT (_jit->start);
   return _jit->pc.uc;
 }