Definition compat_pointer_chunks (chunk1 chunk2: memory_chunk) : Prop :=
  match chunk1, chunk2 with
  | (Mint32 | Many32), (Mint32 | Many32) => True
  | (Mint64 | Many64), (Mint64 | Many64) => True
  | _, _ => False
  end.

Theorem valid_access_free_2: forall chunk ofs p, lo < hi -> ofs + size_chunk chunk > lo -> ofs < hi -> ~(valid_access m2 chunk bf ofs p).