0.7.9.1:

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

diff --git a/src/code/seq.lisp b/src/code/seq.lisp
index 93bfa19..9446dc8 100644 (file)
--- a/src/code/seq.lisp
+++ b/src/code/seq.lisp
@@ -634,10 +634,33 @@
   specified OUTPUT-TYPE-SPEC."
   (let ((type (specifier-type output-type-spec)))
   (cond
+    ((csubtypep type (specifier-type 'list))
+     (cond
+       ((type= type (specifier-type 'list))
+       (apply #'concat-to-list* sequences))
+       ((eq type *empty-type*)
+       (bad-sequence-type-error nil))
+       ((type= type (specifier-type 'null))
+       (if (every (lambda (x) (or (null x)
+                                  (and (vectorp x) (= (length x) 0))))
+                  sequences)
+           'nil
+           (sequence-type-length-mismatch-error type
+                                                ;; FIXME: circular
+                                                ;; list issues.  And
+                                                ;; rightward-drift.
+                                                (reduce #'+
+                                                        (mapcar #'length
+                                                                sequences)))))
+       ((csubtypep (specifier-type '(cons nil t)) type)
+       (if (notevery (lambda (x) (or (null x)
+                                     (and (vectorp x) (= (length x) 0))))
+                     sequences)
+           (apply #'concat-to-list* sequences)
+           (sequence-type-length-mismatch-error type 0)))
+       (t (sequence-type-too-hairy (type-specifier type)))))
     ((csubtypep type (specifier-type 'vector))
      (apply #'concat-to-simple* output-type-spec sequences))
-    ((csubtypep type (specifier-type 'list))
-     (apply #'concat-to-list* sequences))
     (t
      (bad-sequence-type-error output-type-spec)))))