Cleanup linked list

[hkBst]

• Replaces some checked_sub().unwrap_or(0) with saturating_sub().
• Replaces NonNull::from(Box::leak(node)) with Box::into_non_null(node)

[rustbot]

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[hkBst]

This moves code A down into impl block B, but the diff shows B being moved up past A.

So this actually moves into_raw and into_non_null (expand below this seeming addition) into an impl block that is generic over the allocator, such that they can accept Boxes that use an allocator different from the Global one. This is needed for the changes in linked_list.rs to replace Box::leak (which is also generic over allocator).

This probably needs some libs discussion/approval.

[quaternic]

Could you make the diff smaller by separating A into it's own impl block without moving it?

[hkBst]

Good idea. That should probably work. Done now.

[jhpratt]

Pending CI passing

@rustbot author

[hkBst]

@rustbot ready

[jhpratt]

@bors r+ rollup

[bors]

📌 Commit eea3d79 has been approved by jhpratt

It is now in the queue for this repository.