Definition var_name (V: Type) (bdec: ident * globvar V) : ident :=
   fst bdec.Definition no_dups (F V: Type) (fdecs: list (ident * F)) (bdecs: list (ident * globvar V)) : Prop :=
  list_norepet (map (@fst ident F) fdecs ++ map (@var_name V) bdecs).

Lemma inv_find_symbol_fun: forall {ge id id' b}, Senv.find_symbol ge id = Some b -> Senv.find_symbol ge id' = Some b -> id=id'.