id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	difficulty
1703	Arguments being passed to procedure incorrectly	Jakob L. Kreuze	sjamaan	"Here is the offending part of a program I have been writing.

{{{
(define (reduce proc list init)
  (define (reduce-iter list result)
    (if (null? list)
        result
        (reduce-iter (cdr list) (proc result (car list)))))
  (reduce-iter list init))

(define-record-type <vec3>
  (make-vec3 x y z)
  vec3?
  (x vec3-x)
  (y vec3-y)
  (z vec3-z))

;; Macro for destructuring a vec3.
(define-syntax vec3-bind
  (syntax-rules ()
    ((vec3-bind ((names vec) ...)
       body)
     (let-values ((names (values (vec3-x vec)
                                 (vec3-y vec)
                                 (vec3-z vec)))
                  ...)
       body))))

(define (vec3- . vecs)
  ""Return the difference of VECS, as in vector space subtraction.""
  (define (sub u v)
    (vec3-bind (((x1 y1 z1) u) ((x2 y2 z2) v))
      (make-vec3 (- x1 x2) (- y1 y2) (- z1 z2))))
  (if (zero? (length vecs))
      (make-vec3 0 0 0)
      (reduce sub (cdr vecs) (car vecs))))

(vec3- (make-vec3 1.00 1.00 1.00)
       (make-vec3 1.00 1.00 1.00)
       (make-vec3 1.00 1.00 1.00))
}}}

This runs without error on Version 4.13.0 (rev 68eeaaef), but on Version 5.2.0 (rev 317468e4), I get the following runtime error.

{{{

Error: (vec3-x) bad argument type - not a structure of the required type
#<procedure (sub u v)>
<vec3>

	Call history:

	r7rs-raytracer.scm:35: make-vec3	  
	r7rs-raytracer.scm:36: make-vec3	  
	r7rs-raytracer.scm:37: make-vec3	  
	r7rs-raytracer.scm:35: vec3-	  
	r7rs-raytracer.scm:33: reduce	  
	r7rs-raytracer.scm:6: reduce-iter	  
	r7rs-raytracer.scm:5: proc	  
	r7rs-raytracer.scm:29: ##sys#call-with-values	  
	r7rs-raytracer.scm:29: vec3-x	  	<--
}}}

I could not build the master branch, so I was unable to see if this has been resolved.

I suspect the arguments are being passed in the wrong order to 'reduce', somehow. This error only occurs if the number of arguments to vec3- is greater than 2."	defect	closed	major	5.3	compiler	5.2.0	fixed			hard