Section HeapPointsToLemmas.
Implicit Types (x : ptr) (h : heap).
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(* Some derived lemmas *)
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End BlockUpdate.
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(* the automation of the PtUn lemmas *)
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(* First, the mechanism for search-and-replace for the overloaded lemas, *)
(* pattern-matching on heap expressions.                                 *)
Structure tagged_heap := Tag {untag :> heap}.
Definition right_tag := Tag.
Definition left_tag := right_tag.
Canonical found_tag i := left_tag i.
Definition partition_axiom k r (h : tagged_heap) := untag h = k \+ r.
Structure partition (k r : heap) :=
Partition {heap_of :> tagged_heap;
_ : partition_axiom k r heap_of}.

Lemma first_exists A p h (ls : seq A) :
p != null -> llist p ls h ->
exists x r h',
[/\ ls = x :: behead ls, h = p :-> (x, r) \+ h' &
llist r (behead ls) h'].