diff --git a/compiler/ltn.lisp b/compiler/ltn.lisp
index 4ab7a8cdc7220e8e214e18b87c08a485a2668c75..8ac7e257769aea4a721104a863b8e24f137ccb55 100644
--- a/compiler/ltn.lisp
+++ b/compiler/ltn.lisp
@@ -536,7 +536,8 @@
 		     (eq mem type))
 	     (return t))))
 	(:constant
-	 (funcall (second restr) (continuation-value cont))))))
+	 (and (constant-continuation-p cont)
+	      (funcall (second restr) (continuation-value cont)))))))
 
   
 ;;; Template-Args-OK  --  Internal