anchor.diff:             :*return-var-name-base*
              :*stage-names*
              :*stage-type-names*
  -           :*supported-draw-modes*
              :*supported-versions*
              :*valid-contents-symbols*
              :%uniform-name
  
positive.code:    :context
     :stemcells-allowed
     :primitive-in
     ;;
     ;; compilation
     :translate
  
negative.code:    :*draw-modes*
     :*stage-names*
     :*stage-type-names*
     :*supported-versions*
     :*valid-contents-symbols*
     ;;
  