diff --git a/quasiquote.lisp b/quasiquote.lisp
index 1014f3e9f155ecc083a4cd740ddd7805b8ab5138..d0a36e2c664539e6a1f6dc587380d866a953e92b 100644
--- a/quasiquote.lisp
+++ b/quasiquote.lisp
@@ -33,7 +33,7 @@
 (make-single-arg-form unquote-nsplicing)
 (defun make-vector-form (&rest x) (list* 'vector x))
 (defun vector-form-p (x)
-  (and (proper-list-p x) (eq (car x) 'vector)))
+  (and (listp x) #|(alexandria:proper-list-p x)|# (eq (car x) 'vector)))
 
 (defmacro quote (x) (list 'cl:quote x))
 (defmacro quasiquote (x) (quasiquote-expand x))