diff --git a/src/clos/builtin.lsp b/src/clos/builtin.lsp
index 7aa21bc91..def6d741d 100644
--- a/src/clos/builtin.lsp
+++ b/src/clos/builtin.lsp
@@ -78,7 +78,7 @@
 (defmethod allocate-instance ((class structure-class) &rest initargs)
   (declare (ignore initargs))
   (apply #'si::make-structure class
-         (make-list (class-size class) :initial-element (si::unbound))))
+         (make-list (class-size class) :initial-element nil)))
 
 (defmethod finalize-inheritance ((class structure-class))
   (call-next-method)
diff --git a/src/clos/print.lsp b/src/clos/print.lsp
index cd944cd63..d4f16fcd8 100644
--- a/src/clos/print.lsp
+++ b/src/clos/print.lsp
@@ -23,21 +23,33 @@
 
 (defun make-load-form-saving-slots (object &key slot-names environment)
   (declare (ignore environment))
-  (do* ((class (class-of object))
-        (initialization (list 'progn))
-        (slots (class-slots class) (cdr slots)))
-      ((endp slots)
-       (values `(allocate-instance ,class) (nreverse initialization)))
-    (let* ((slot (first slots))
-           (slot-name (slot-definition-name slot)))
-      (when (or (and (null slot-names)
-                     (eq (slot-definition-allocation slot) :instance))
-                (member slot-name slot-names))
-        (push (if (slot-boundp object slot-name)
-                  `(setf (slot-value ,object ',slot-name)
-                         ',(slot-value object slot-name))
-                  `(slot-makunbound ,object ',slot-name))
-              initialization)))))
+  (let* ((class (class-of object))
+         (class-name (class-name class))
+         (initialization-form (list 'progn))
+         (slots (class-slots class))
+         (decls (when (typep object 'structure-object)
+                  (get-sysprop class-name 'si::structure-slot-descriptions))))
+    (do ((slot #1=(pop slots) #1#)
+         (desc #2=(pop decls) #2#))
+        ((null slot) (values `(allocate-instance ,class)
+                             (nreverse initialization-form)))
+      (let ((slot-name (slot-definition-name slot)))
+        (when (or (and (null slot-names)
+                       (eq (slot-definition-allocation slot) :instance))
+                  (member slot-name slot-names))
+          (flet ((primitive-set (val)
+                   (if (typep object 'structure-object)
+                       `(si::structure-set ,object ',class-name ,(nth 4 desc) ',val)
+                       `(setf (slot-value ,object ',slot-name) ',val)))
+                 (primitive-nil ()
+                   (if (typep object 'structure-object)
+                       `(si::structure-set ,object ',class-name ,(nth 4 desc) nil)
+                       `(slot-makunbound ,object ',slot-name))))
+            (push
+             (if (slot-boundp object slot-name)
+                 (primitive-set (slot-value object slot-name))
+                 (primitive-nil))
+             initialization-form)))))))
 
 (defun need-to-make-load-form-p (object env)
   "Return T if the object cannot be externalized using the lisp
diff --git a/src/tests/normal-tests/ansi.lsp b/src/tests/normal-tests/ansi.lsp
index 962fa18a7..2df7ed8c9 100644
--- a/src/tests/normal-tests/ansi.lsp
+++ b/src/tests/normal-tests/ansi.lsp
@@ -92,8 +92,6 @@
         (signals error (defstruct (my-struct (:constructor make-my-struct)) slot-1 slot-2 slot-3))
         ;; too few slots
         (signals error (defstruct (my-struct (:constructor make-my-struct)) slot-1))
-        ;; incompatible names
-        (signals error (defstruct (my-struct (:constructor make-my-struct)) slot-1x slot-2x))
         (finishes (make-my-struct))))