(define-library (t)
  (import (primitives+builtins))
  (begin
    (let-syntax ((when (syntax-rules ()
                         ((_ test body ...)
                          (if test (begin body ...))))))
      (when #t
        (display "blah")
        (newline)))
    (let ((x 123))
      (let-syntax ((m (syntax-rules ()
                        ((_) x))))
        (lambda (x)
          (m))))))