[cl-gd-devel] Funky compile warnings with (with-thickness )

[Rusty Shackleford]

I'm using (with-thickness (5) to draw some lines, and when I compile the
code (in emacs slime with C-c C-k) I get a bunch of messages that look
like:

; ==>
;   (SB-ALIEN-INTERNALS:%SAP-ALIEN ALIEN
;
'#<SB-ALIEN-INTERNALS:ALIEN-RECORD-TYPE (STRUCT
;
CL-GD::GD-IMAGE
;
(CL-GD::PIXELS
;
#)
;
(CL-GD::SX
;
#)
;
(CL-GD::SY
;
#)
;
(CL-GD::COLORS-TOTAL
;
#)
;
(CL-GD::RED ..))>)
;
; note: unable to
;   optimize
; because:
;   could not optimize away %SAP-ALIEN: forced to do runtime
; allocation of alien-value structure
; compilation unit finished

What the heck does this mean?  Here's the code that causes the pain:

; This section draws the map.
(require "cl-gd")
(cl-gd:with-image* (*pngwidth* *pngheight*)
    (cl-gd:allocate-color 190 190 190)
    (let ((red (cl-gd:allocate-color 163 83 84))
          (green (cl-gd:allocate-color 104 156 84))
          (yellow (cl-gd:allocate-color 236 236 236))
          (black (cl-gd:allocate-color 0 0 0)))

      ;; Draw all towns.
      (dolist (town *towns*)
        (cl-gd:draw-filled-circle (mapdim (getf town :lat) *pngwidth*)
                                  (mapdim (getf town :long) *pngheight*)
                                  20 :color black)

        ;; Draw roads between neighboring towns.
        (cl-gd:with-thickness (5)
                              (dolist (neighbor (getf town :neighbors))
                                (cl-gd:draw-line (mapdim (getf town :lat) *pngwidth*)
                                                 (mapdim (getf town :long) *pngheight*)
                                                 (mapdim (getf (town-lookup neighbor *towns*) :lat) *pngwidth*)
                                                 (mapdim (getf (town-lookup neighbor *towns*) :long) *pngheight*)
                                                 :color black))))

      ;; Draw start town as green circle.
      (cl-gd:draw-filled-circle (mapdim (getf *start-town* :lat) *pngwidth*)
                                (mapdim (getf *start-town* :long) *pngheight*)
                                15 :color green)
      ;; Fill in evaluation function's choices.
       (dolist (town *path*)
        (cl-gd:draw-filled-circle (mapdim (getf town :lat) *pngwidth*)
                                  (mapdim (getf town :long) *pngheight*)
                                  15 :color yellow))

       ;; Draw goal town as red circle.
       (cl-gd:draw-filled-circle (mapdim (getf *goal-town* :lat) *pngwidth*)
                                 (mapdim (getf *goal-town* :long) *pngheight*)
                                 15 :color red))

    (cl-gd:write-image-to-file "/var/www/website/draw1.png" :compression-level 6 :if-exists :supersede))

Thanks for the help.