prefer-clone-from

Prefer Clone.cloneFrom when replacing a cloneable value

Assigning a newly cloned value discards storage that the destination may be able to reuse.
Instead, you SHOULD call cloneFrom so the destination can reuse its existing allocation.

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

Reported

import { rc } from "destack:memory";

function replace(target: &exclusive rc.Rc<int32>, source: &readonly rc.Rc<int32>): void {
    *target = source.clone();
}
Accepted

import { rc } from "destack:memory";

function replace(target: &exclusive rc.Rc<int32>, source: &readonly rc.Rc<int32>): void {
    target.cloneFrom(source);
}
Prior art

- Clippy · assigningclones

language/linter/src/rules/performance/preferclonefrom.rs:8