Definition StoreEffect (tv:val)(vl : list memval) (b:Values.block) (z:Z):bool :=
match tv with Vptr bb ofs => eq_block bb b &&
zle (Ptrofs.unsigned ofs) z && zlt z (Ptrofs.unsigned ofs + Z.of_nat (length vl))
| _ => false
end.

Lemma freelist_curWR l: forall m m' (FR: Mem.free_list m l = Some m')
b z (EFF : FreelistEffect m l b z = true),
Mem.perm m b z Cur Writable.