anchor.diff:    ; Cfg.auto_reflect                 = None
     ; Cfg.strong_reduction_ok          = true
     ; Cfg.requires_binder_substitution = false
  -  ; Cfg.interpretation               = interp
  -  ; Cfg.interpretation_nbe           = nbe_interp
  +  ; Cfg.interpretation               = timing_int nm interp
  +  ; Cfg.interpretation_nbe           = timing_nbe nm nbe_interp
     }
   
   let mk_total_interpretation_1 (f:'a -> 'r)
  
positive.code:   ; Cfg.interpretation_nbe           = fun _cb -> NBETerm.dummy_interp s.name
    }
  
  let mk nm arity nunivs interp nbe_interp =
    let nm = E.fstar_tactics_lid' ["Builtins"; nm] in
    { Cfg.name                         = nm
  
negative.code:   ; Cfg.auto_reflect                 = Some (arity - 1)
    ; Cfg.strong_reduction_ok          = true
    ; Cfg.requires_binder_substitution = true
    ; Cfg.interpretation               = timing_int nm interp
    ; Cfg.interpretation_nbe           = timing_nbe nm nbe_interp
    }
  
  let native_tactics () = list_all ()
  