rust/src/liballoc/tests, branch 1.45.2

Remove flaky test and document the other's flakiness

2020-05-29T10:24:26+00:00

Add tests

2020-05-23T15:51:02+00:00

Auto merge of #72227 - nnethercote:tiny-vecs-are-dumb, r=Amanieu

2020-05-19T15:12:12+00:00

Tiny Vecs are dumb. Currently, if you repeatedly push to an empty vector, the capacity growth sequence is 0, 1, 2, 4, 8, 16, etc. This commit changes the relevant code (the "amortized" growth strategy) to skip 1 and 2, instead using 0, 4, 8, 16, etc. (You can still get a capacity of 1 or 2 using the "exact" growth strategy, e.g. via `reserve_exact()`.) This idea (along with the phrase "tiny Vecs are dumb") comes from the "doubling" growth strategy that was removed from `RawVec` in #72013. That strategy was barely ever used -- only when a `VecDeque` was grown, oddly enough -- which is why it was removed in #72013. (Fun fact: until just a few days ago, I thought the "doubling" strategy was used for repeated push case. In other words, this commit makes `Vec`s behave the way I always thought they behaved.) This change reduces the number of allocations done by rustc itself by 10% or more. It speeds up rustc, and will also speed up any other Rust program that uses `Vec`s a lot. In theory, the change could increase memory usage, but in practice it doesn't. It would be an unusual program where very small `Vec`s having a capacity of 4 rather than 1 or 2 would make a difference. You'd need a *lot* of very small `Vec`s, and/or some very small `Vec`s with very large elements. r? @Amanieu

Auto merge of #71447 - cuviper:unsized_cow, r=dtolnay

2020-05-19T08:08:48+00:00

impl From for Box, Rc, and Arc These forward `Borrowed`/`Owned` values to existing `From` impls. - `Box` is a fundamental type, so it would be a breaking change to add a blanket impl. Therefore, `From` is only implemented for `[T]`, `str`, `CStr`, `OsStr`, and `Path`. - For `Rc` and `Arc`, `From` is implemented for everything that implements `From` the borrowed and owned types separately.

Tiny Vecs are dumb.

2020-05-18T05:26:59+00:00

Currently, if you repeatedly push to an empty vector, the capacity growth sequence is 0, 1, 2, 4, 8, 16, etc. This commit changes the relevant code (the "amortized" growth strategy) to skip 1 and 2 in most cases, instead using 0, 4, 8, 16, etc. (You can still get a capacity of 1 or 2 using the "exact" growth strategy, e.g. via `reserve_exact()`.) This idea (along with the phrase "tiny Vecs are dumb") comes from the "doubling" growth strategy that was removed from `RawVec` in #72013. That strategy was barely ever used -- only when a `VecDeque` was grown, oddly enough -- which is why it was removed in #72013. (Fun fact: until just a few days ago, I thought the "doubling" strategy was used for repeated push case. In other words, this commit makes `Vec`s behave the way I always thought they behaved.) This change reduces the number of allocations done by rustc itself by 10% or more. It speeds up rustc, and will also speed up any other Rust program that uses `Vec`s a lot.

Rollup merge of #71485 - arlopurcell:binary_heap_retain, r=Amanieu

2020-04-24T23:35:59+00:00

Add BinaryHeap::retain as suggested in #42849 This PR implements retain for BinaryHeap as suggested in #42849. This is my first PR for Rust, so please let me know if I should be doing anything differently, thanks!

Add BinaryHeap::retain as suggested in #42849

2020-04-24T09:44:20+00:00

liballoc: more compact way to adjust test sizes for Miri

2020-04-23T18:05:01+00:00

Add tests from Cow

2020-04-22T21:16:21+00:00

Disable try_reserve tests on Android

2020-04-09T14:55:12+00:00