Function assert_note_existed_by

pub fn assert_note_existed_by<Note>(
    block_header: BlockHeader,
    hinted_note: HintedNote<Note>,
) -> ConfirmedNote<Note>
where
    Note: NoteHash

Asserts that a note existed in the note hash tree by the time a block was mined.

Proves note inclusion at block_header by checking membership of the note's unique note hash, and returns a ConfirmedNote describing it.

Cross-contract notes

Unlike the nullification helpers, this works for notes of any contract, not just the executing one: note hashes are siloed with the note's own contract address (carried by the HintedNote) and no secret keys are involved.

To reason about whether such a note has been nullified, see assert_local_note_was_nullified_by and assert_local_note_was_not_nullified_by, which — in contrast — can only be used for the executing contract's own notes.