for both Vec<T> and String
- eliminates the boolean first flag in fn join()
for String only
- eliminates repeated bounds checks in join(), concat()
- adds fast paths for small string separators up to a len of 4 bytes
Make the OOM hook return `()` rather than `!`
Per discussion in https://github.com/rust-lang/rust/issues/51245#issuecomment-393651083
This allows more flexibility in what can be done with the API. This also
splits `rtabort!` into `dumb_print` happening in the default hook and
`abort_internal`, happening in the actual oom handler after calling the
hook. Registering an empty function thus makes the oom handler not print
anything but still abort.
Cc: @alexcrichton
Make const decoding thread-safe.
This is an alternative to https://github.com/rust-lang/rust/pull/50957. It's a proof of concept (e.g. it doesn't adapt metadata decoding, just the incr. comp. cache) but I think it turned out nice. It's rather simple and does not require passing around a bunch of weird closures, like we currently do.
If you (@Zoxc & @oli-obk) think this approach is good then I'm happy to finish and clean this up.
Note: The current version just spins when it encounters an in-progress decoding. I don't have a strong preference for this approach. Decoding concurrently is equally fine by me (or maybe even better because it doesn't require poisoning).
r? @Zoxc
Make some std::intrinsics `const fn`s
Making some rustc intrinsics (`ctpop`, `cttz`, `ctlz` and `bswap`) `const fn`s.
This is a pre-step to being able to make `swap_bytes`, `to_be` and `from_be` constant functions. That in itself could be ergonomic and useful. But even better is that it would allow `Ipv4Addr::new` etc becoming `const fn`s as well. Which might be really useful since I find it quite common to want to define them as constants.
r? @oli-obk
The old text was: "The precise definition is: a type T is Sync if &T is Send."
Since we've also got
```
impl<'a, T> Send for &'a T
where
T: Sync + ?Sized,
```
I purpose we can change the `if` to `if and only if` to make it more precise.
Arc downcast
Implement `downcast` for `Arc<Any + Send + Sync>` as part of #44608, and gated by the same `rc_downcast` feature.
This PR is mostly lightly-edited cut'n'paste.
This has two additional changes:
- The `downcast` implementation needs `Any + Send + Sync` implementations for `is` and `Debug`, and I added `downcast_ref` and `downcast_mut` for completeness/consistency. (Can these be insta-stabilized?)
- At @SimonSapin's suggestion, I converted `Arc` and `Rc` to use `NonNull::cast` to avoid an `unsafe` block in each which tidied things up nicely.
Per discussion in https://github.com/rust-lang/rust/issues/51245#issuecomment-393651083
This allows more flexibility in what can be done with the API. This also
splits `rtabort!` into `dumb_print` happening in the default hook and
`abort_internal`, happening in the actual oom handler after calling the
hook. Registering an empty function thus makes the oom handler not print
anything but still abort.
Cc: @alexcrichton
Register outlives predicates from queries the right way around.
Closes#49354
The region constraints from queries need to be reversed from sub to outlives.
Note: wf checking reports these errors before NLL, so I'm not sure if there's any case when these predicates need to be created at all.
cc @nikomatsakis
Rollup of 7 pull requests
Successful merges:
- #49546 (Stabilize short error format)
- #51123 (Update build instructions)
- #51146 (typeck: Do not pass the field check on field error)
- #51193 (Fixes some style issues in rustdoc "implementations on Foreign types")
- #51213 (fs: copy: Use File::set_permissions instead of fs::set_permissions)
- #51227 (mod.rs isn't beautiful)
- #51240 (Two minor parsing tweaks)
Failed merges:
We only need to implement it for `Any + Send + Sync` because in practice
that's the only useful combination for `Arc` and `Any`.
Implementation for #44608 under the `rc_downcast` feature.
fs: copy: Use File::set_permissions instead of fs::set_permissions
We already got the open file descriptor at this point.
Don't make the kernel resolve the path again.
Update build instructions
It get stuck at the cloning step.
`./x.py build `
Updating only changed submodules
Updating submodule src/llvm
Submodule 'src/llvm' (https://github.com/rust-lang/llvm.git) registered for path 'src/llvm'
Cloning into '/home/username/rust/src/llvm'...
When subtracting an Instant from another, the function will panick when `RHS > self`, but the error message confusingly displays a different error:
```rust
let i = Instant::now();
let other = Instant::now();
if other > i {
println!("{:?}", i - other);
}
```
This results in a panic:
```
thread 'test_instant' panicked at 'other was less than the current instant', libstd/sys/unix/time.rs:292:17
```
