anchor.diff:  
   (define-struct test-struct
     (x char :initform #\A)
  -  (y float :initform 123.0s0))
  +  (y float :initform 123.0e0))
   
   (deftest structs.named.alloc-read-write-free
       (let ((ts 'test-struct))
  
positive.code:     (let ((ts '(struct ()
                  (x char)
                  (y float))))
        (and (let* ((struct (ht 'x #\A 'y 123.0s0))
                    (out (ht 'x #\B 'y 124.0s0))
                    (p (alloc ts struct)))
               (unwind-protect
                   (and (equalp struct (deref p ts))
  
negative.code:                            'llong  123
                             'ullong 123
                             'pointer (cffi:null-pointer)
                             'single 123.0e0
                             'double 123.0d0
                             'char #\A
                             'wchar #\A
  