Notation val_inject:=Val.inject.
(*A value that is (if its a pointer) not dangling wrt m - a condition like this will probably be need to imposed on after-external return values (and thus also on the values returned by halted)*)
Definition val_valid (v:val) (m:mem):Prop :=
match v with Vptr b ofs => Mem.valid_block m b | _ => True
end.
(*memories that do not contain "dangling pointers"*)
Definition mem_wd m := Mem.inject_neutral (Mem.nextblock m) m.

Lemma mem_wd_free: forall m b lo hi m' (WDm: mem_wd m)
(FREE: Mem.free m b lo hi = Some m'), mem_wd m'.