Comment 8 for bug 1907252

(defun foo (l)
  (declare (optimize speed (safety 0)))
  (with-alien ((z (c-string :external-format :utf-8) (truly-the string (car l))))
    (assert (equal z (car l)))))

(loop repeat 3
      do
      (sb-thread:make-thread (lambda ()
                               (declare (optimize speed (safety 0)))
                               (let ((z (list (copy-seq "teststring"))))
                                 (loop (foo z))))))
(loop (sb-ext:gc)
      (sleep 0.0001))