block array passed to emit causes flow-id error

[cbaggers]

this code

(glsl-code
  (translate
   (make-stage :geometry '((pos (:vec2 1)) (id (:int 1))) nil '(:450) 
			   '((declare (output-primitive :kind :triangle-strip :max-vertices 6))
				 (let* ((size 0.03)
						(hsize (* size 0.5)))
				   (emit () (v! (+ (aref pos 0) (v! (- hsize)    hsize)) 0 1)
						 (v! 0 1)
						 id)
				   (emit () (v! (+ (aref pos 0) (v! (- hsize) (- hsize))) 0 1)
						 (v! 0 0)
						 id)
				   (emit () (v! (+ (aref pos 0) (v!     hsize (- hsize))) 0 1)
						 (v! 1 0)
						 id)
				   (end-primitive)
				   (emit () (v! (+ (aref pos 0) (v! (- hsize)    hsize)) 0 1)
						 (v! 0 1)
						 id)
				   (emit () (v! (+ (aref pos 0) (v!     hsize (- hsize))) 0 1)
						 (v! 1 0)
						 id)
				   (emit () (v! (+ (aref pos 0) (v!     hsize    hsize)) 0 1)
						 (v! 1 1)
						 id)
				   (end-primitive)
				   (values)))
			   nil :triangles)))

gives this

Varjo: compiled object must be given flow id/s when created: type - #(VARJO:V-VEC2
                                                                      (VARJO::V-BLOCK-ARRAY
                                                                       "v_in"
                                                                       VARJO:V-INT
                                                                       (1)))
   [Condition of type VARJO-CONDITIONS:FLOW-IDS-MANDATORY]