bug#38486: Compiler does not terminate

[Zack Marvel]

Hello,

When compiling the following program, the compiler does not terminate.


(define (find-closest-intersection board)
  (let ((cols (vector-length board))
        (rows (vector-length (vector-ref board 0))))
    (let col-loop ((col 0)
                   (min-distance 999))
      (if (< col cols)
          (col-loop
           (1+ col)
           (let row-loop ((row 0)
                          (min-distance min-distance))
             (if (< row rows)
                 (row-loop (1+ row) min-distance)
                 min-distance)))
          min-distance))))


Here is the output of the compiler:


$ guile ~/src/advent-of-code/2019/guile_infinite_loop.scm
;;; note: source file 
/home/zack/src/advent-of-code/2019/guile_infinite_loop.scm
;;;       newer than compiled 
/home/zack/.local/src/guile-2.2.6/cache/guile/ccache/2.2-LE-8-3.A/home/zack/src/advent-of-code/2019/guile_infinite_loop.scm.go
;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
;;;       or pass the --no-auto-compile argument to disable.
;;; compiling /home/zack/src/advent-of-code/2019/guile_infinite_loop.scm


If I flatten the two loops into one, the program compiles. If I use 
constants instead of vector sizes, it also compiles.

I can produce this behavior with Guile 2.2.4 and 2.2.6. I'm running 
Debian 10 amd64, and I compiled Guile with GCC 8.3.0.

Please let me know if I can provide more information!

Best regards,
Zack Marvel