redundant-iter-cloned

Disallow cloning iterator elements that are only borrowed afterward

performancewarningautomatic fixmodule

Cloning iterator elements is unnecessary when the following operation only observes them through readonly borrows. Instead, you SHOULD operate on the borrowed elements directly.

Reported

1import { Iterator } from "destack:iter";2 3struct Label {4    values: ^int32[];5}6 7function lengths(values: Iterator<&readonly Label>): Iterator<isize> {8    return values.cloned().map((value) => value.values.length);9}

Accepted

1import { Iterator } from "destack:iter";2 3struct Label {4    values: ^int32[];5}6 7function lengths(values: Iterator<&readonly Label>): Iterator<isize> {8    return values.map((value) => value.values.length);9}