+;;; In addition to the upper-case constraint above, if the logical-pathname
+;;; contains a string component in e.g. the directory, name and type slot,
+;;; these should be valid "WORDS", according to CLHS 19.3.1.
+;;; FIXME: currently SBCL throws NAMESTRING-PARSE-ERROR: should this be
+;;; a TYPE-ERROR?
+
+;; error: directory-component not valid
+(assert (not (ignore-errors
+ (make-pathname :host "FOO" :directory "!bla" :name "bar"))))
+
+;; error: name-component not valid
+(assert (not (ignore-errors
+ (make-pathname :host "FOO" :directory "bla" :name "!bar"))))
+
+;; error: type-component not valid.
+(assert (not (ignore-errors
+ (make-pathname :host "FOO" :directory "bla" :name "bar"
+ :type "&baz"))))
+