Possibly incorrect lemma in example-archive (src/example-archive/simple-examples/working/list_2.c) #111

void lemma_make_segment_from_parts(struct list_node *head, struct list_node *tail) 
/*@
   requires take H = Owned<struct list_node>(head);
            take LS = IntListSeg(H.next, tail);
            !(head == tail);
    ensures take LS_NEW = IntListSeg(head, tail);
            LS_NEW == Seq_Cons { val: H.val, next: LS };
@*/ {
}

void lemma_intlist_seq_snoc(struct list_node *head, struct list_node *prev_curr)
/*@
  requires take l1 = IntListSeg(head, prev_curr);
           take v = Owned<struct list_node>(prev_curr);
           v.next != prev_curr;
  ensures take l2 = IntListSeg(head, v.next);
          l2 == append(l1, Seq_Cons { val: v.val, next: Seq_Nil {} });
  @*/
{
  /*@ split_case (ptr_eq(head,prev_curr)); @*/
  if(head == prev_curr) {
    /*@ assert (l1 == Seq_Nil {}); @*/
    /*@ unfold append(l1, Seq_Cons { val: v.val, next: Seq_Nil {} }); @*/
    /*@ split_case (ptr_eq(prev_curr, v.next)); @*/
    return;
  } else {
    struct list_node *prev_curr_next = prev_curr->next;
    lemma_intlist_seq_snoc(head->next, prev_curr);
    /*@ split_case (ptr_eq(head,prev_curr)); @*/
    lemma_make_segment_from_parts(head, prev_curr_next);
    /*@ assert (true); @*/
  }
}