anchor.diff:                              `((%setq ~%ret ,_.)
                                 (%%vm-go-nil ~%ret ,next)))
                           ,@(awhen (vars-to-identity ._)
  -						    `((%setq ~%ret (%%vm-scope ,@!))))
  +						    `((%setq ~%ret ,(make-vm-scope !))))
                          (%%vm-go ,end-tag)
                          ,next))
   			     args)
  
positive.code: (defun compiler-macroexpand (x)
    (expander-expand 'compiler x))
  
  (define-filter vars-to-identity (x)
    (? (atom x)
       `(identity ,x)
  
negative.code:     `(identity nil)))
  
  (define-compiler-macro setq (&rest args)
    (make-vm-scope (filter (fn `(%setq ,_. ,._.)) (group args 2))))
  
  (define-compiler-macro ? (&rest body)
    (with (tests (group body 2)
  