prefer-with-capacity

Prefer withCapacity over immediate reservation after construction

Constructing an empty collection and immediately reserving capacity splits one initialization across two operations.
Instead, you SHOULD construct the collection with withCapacity.

- Category: performance
- Level: warning
- Fix: suggestion
- Scope: module

Reported

function collect(capacity: usize): ^int32[] {
    let values: ^int32[] = Array.new();
    values.reserve(capacity);

    return values;
}
Accepted

function collect(capacity: usize): ^int32[] {
    let values: ^int32[] = Array.withCapacity(capacity);

    return values;
}
Prior art

- Clippy · reserveafterinitialization

language/linter/src/rules/performance/preferwithcapacity.rs:25