anchor.diff:  (defun make-boolean (boolean result successor)
     (sicl-mir:make-assignment-instruction
      (sicl-mir:make-external-input boolean)
  -   result successor))
  +   result
  +   successor))
   
   (defun compile-test (argument-asts constructor context)
     (with-accessors ((results results)
  
positive.code: ;;;
  ;;; Compile a TYPEQ-AST.
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Compile a LEXICAL-AST.
  
negative.code: 			(typep successor 'sicl-mir:instruction))
  		      successors))
      (error "illegal successors: ~s" results))
    (when (and (null successors) (not (null results)))
      (error "Illegal combination of results and successors"))
    (make-instance 'context
      :results results
  