`useless_let_if_seq` issue?

I have this code:

let mut size: usize = 0;
let mut page: u64 = 1;

if let Some(pagination) = pagination {
    size = pagination.size().try_into().unwrap();
    page = pagination.page();
}

and clippy is saying:

warning: `if _ { .. } else { .. }` is an expression
239 | /     let mut page: u64 = 1;
240 | |
241 | |     if let Some(pagination) = pagination {
242 | |         size = pagination.size().try_into().unwrap();
243 | |         page = pagination.page();
244 | |     }
    | |_____^ help: it is more idiomatic to write: `let <mut> page = if let Some(pagination) = pagination { ..; pagination.page() } else { 1 };`
    |
    = note: you might not need `mut` at all
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_let_if_seq
    = note: `-W clippy::useless-let-if-seq` implied by `-W clippy::nursery`
    = help: to override `-W clippy::nursery` add `#[allow(clippy::useless_let_if_seq)]`

So I think I should change it to:

let size = input
    .pagination
    .as_ref()
    .map_or(0, |pagination| pagination.size().try_into().unwrap());

let page = input.pagination.as_ref().map_or(1, Input::page);

Am I right?

Isn't the check on the .map_or() duplicated now? Is this a performance regression?

Start with the useless_let_if_seq lint entry point and its documentation, then compare the suggested rewrite with the Rust example in the issue. Determine whether the rewrite duplicates the pagination check or changes performance, and document the conclusion or identify the lint behavior that needs correction.