Remark permutation_norepet:
forall (A: Type) (l l': list A), Permutation l l' -> list_norepet l -> list_norepet l'.

Lemma build_compilenv_domain:
forall f cenv sz id ofs,
build_compilenv f = (cenv, sz) ->
cenv!id = Some ofs -> In id (map fst (Csharpminor.fn_vars f)).