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Refactor collections::List<T> to avoid using managed boxes #12620

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brunoabinader opened this issue Feb 28, 2014 · 3 comments
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Refactor collections::List<T> to avoid using managed boxes #12620

brunoabinader opened this issue Feb 28, 2014 · 3 comments

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@brunoabinader
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After closing #12344, we should think about the best strategy for replacing usage of managed boxes inside List<T>. @alexcrichton, @bill-myers and @eddyb provided good hints on how we should implement List<T> internally (i.e. instead of using an enum, use a struct-based approach with 'head' and 'tail').
@brunoabinader
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My initial idea was to simply replace manage box with owned or even refcounted box. I have some prototypes ready however I'd require some help writing benchmark tests to verify. The idea that Cons and Nil as duplicates for the Option behavior is also correct, so it might be simple to just get rid of enum and go for a struct, Option-based approach.

@huonw
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huonw commented Feb 28, 2014

Using Rc<...> seems like a good, preferable idea, because it allows for sharing tails.

(With owned boxes, the linked list becomes a plain owned stack, and std::vec_ng::Vec (or, ~[]) are better versions of these stacks on most dimensions: lower memory use, better cache locality, still have (amoritised) O(1) push/pop, O(1) indexing/length...)

@huonw huonw added the A-libs label Feb 28, 2014
@pongad
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pongad commented Apr 2, 2014

Close since List has been removed?

flip1995 pushed a commit to flip1995/rust that referenced this issue May 17, 2024
@bors
Auto merge of rust-lang#12620 - Nilstrieb:dupattr, r=xFrednet
412b691 
Handle `rustc_on_unimplemented` in duplicated_attributes

```rust
#[rustc_on_unimplemented(
    on(
        _Self = "&str",
        label = "`a"
    ),
    on(
        _Self = "alloc::string::String",
        label = "a"
    ),
)]
```

The lint treats this as a repetition because `rustc_on_unimplemented::on::label` appears twice, but that's ok.

Fixes rust-lang#12619

changelog: [`duplicated_attributes`]: fix handling of `rustc_on_unimplemented`
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@brunoabinader @huonw @thestinger @pongad