gencgc: More precise conservatism for pointers to boxed pages.

[sbcl.git] / src / code / destructuring-bind.lisp

diff --git a/src/code/destructuring-bind.lisp b/src/code/destructuring-bind.lisp
index 7e9b8e1..c485b75 100644 (file)
--- a/src/code/destructuring-bind.lisp
+++ b/src/code/destructuring-bind.lisp
@@ -9,14 +9,19 @@
 
 (in-package "SB!IMPL")
 
-(defmacro-mundanely destructuring-bind (lambda-list arg-list &rest body)
+(defmacro-mundanely destructuring-bind (lambda-list expression &body body)
   #!+sb-doc
-  "Bind the variables in LAMBDA-LIST to the contents of ARG-LIST."
-  (let* ((arg-list-name (gensym "ARG-LIST-")))
+  "Bind the variables in LAMBDA-LIST to the corresponding values in the
+tree structure resulting from the evaluation of EXPRESSION."
+  (let ((whole-name (gensym "WHOLE")))
     (multiple-value-bind (body local-decls)
-       (parse-defmacro lambda-list arg-list-name body nil 'destructuring-bind
-                       :anonymousp t
-                       :doc-string-allowed nil)
-      `(let ((,arg-list-name ,arg-list))
-        ,@local-decls
-        ,body))))
+        (parse-defmacro lambda-list whole-name body nil 'destructuring-bind
+                        :anonymousp t
+                        :doc-string-allowed nil
+                        :wrap-block nil)
+      `(let ((,whole-name ,expression))
+         ;; This declaration-as-assertion should protect us from
+         ;; (DESTRUCTURING-BIND (X . Y) 'NOT-A-LIST ...).
+         (declare (type list ,whole-name))
+         ,@local-decls
+         ,body))))