0.8.0.21

[sbcl.git] / src / code / defstruct.lisp

diff --git a/src/code/defstruct.lisp b/src/code/defstruct.lisp
index 8b83b55..e523eed 100644 (file)
--- a/src/code/defstruct.lisp
+++ b/src/code/defstruct.lisp
@@ -604,23 +604,27 @@
                                                           :index 0
                                                           :type t)))
   (multiple-value-bind (name default default-p type type-p read-only ro-p)
-      (cond
-       ((listp spec)
-       (destructuring-bind
-           (name
-            &optional (default nil default-p)
-            &key (type nil type-p) (read-only nil ro-p))
-           spec
-         (values name
-                 default default-p
-                 (uncross type) type-p
-                 read-only ro-p)))
-       (t
-       (when (keywordp spec)
-         (style-warn "Keyword slot name indicates probable syntax ~
-                      error in DEFSTRUCT: ~S."
-                     spec))
-       spec))
+      (typecase spec
+       (symbol
+        (when (keywordp spec)
+          (style-warn "Keyword slot name indicates probable syntax ~
+                       error in DEFSTRUCT: ~S."
+                      spec))
+        spec)
+       (cons
+        (destructuring-bind
+              (name
+               &optional (default nil default-p)
+               &key (type nil type-p) (read-only nil ro-p))
+            spec
+          (values name
+                  default default-p
+                  (uncross type) type-p
+                  read-only ro-p)))
+       (t (error 'simple-program-error
+                 :format-control "in DEFSTRUCT, ~S is not a legal slot ~
+                                   description."
+                 :format-arguments (list spec))))
 
     (when (find name (dd-slots defstruct)
                :test #'string=