Optimize `Vec::insert` for the case where `index == len`.
By skipping the call to `copy` with a zero length. This makes it closer
to `push`.
I did this recently for `SmallVec`
(https://github.com/servo/rust-smallvec/pull/282) and it was a big perf win in
one case. Although I don't have a specific use case in mind, it seems
worth doing it for `Vec` as well.
Things to note:
- In the `index < len` case, the number of conditions checked is
unchanged.
- In the `index == len` case, the number of conditions checked increases
by one, but the more expensive zero-length copy is avoided.
- In the `index > len` case the code now reserves space for the extra
element before panicking. This seems like an unimportant change.
Wesley Wiser [Fri, 1 Oct 2021 01:58:49 +0000 (21:58 -0400)]
Don't assert polymorphization has taken effect in const eval
Const eval no longer runs MIR optimizations so unless this is getting
run as part of a MIR optimization like const-prop, there can be unused
type parameters even if polymorphization is enabled.
Matthias Krüger [Thu, 30 Jun 2022 17:55:57 +0000 (19:55 +0200)]
Rollup merge of #98717 - RalfJung:make-tidy-less-annoying, r=jyn514
get rid of tidy 'unnecessarily ignored' warnings
I think these warnings are quite pointless: when I say `allow(foo)` in my code, that doesn't necessarily mean that I expect `foo` to happen -- it just means that I am okay with `foo` happening.
For example, having to add and remove `ignore-tidy-linelength` as the longest line in the file keeps growing and shrinking is just annoying and doesn't benefit anyone, IMO. This usually incurs *two* CI roundtrips: first CI tells you that line lengths in your test file are ignored unnecessarily, so you go and remove that attribute; then CI tells you that now your line numbers changed, so you re-bless your tests (often takes >5min if parts of rustc need rebuilding because `./x.py fmt` changed something somewhere). That's just a lot of wasted effort and time and patience.
This adapts llvm-wrapper to use the new alternative where available, following https://rust-lang.zulipchat.com/#narrow/stream/187780-t-compiler.2Fwg-llvm/topic/LLVMConstExtractValue.20removal.
Matthias Krüger [Thu, 30 Jun 2022 17:55:51 +0000 (19:55 +0200)]
Rollup merge of #98503 - RalfJung:scope-race, r=m-ou-se
fix data race in thread::scope
Puts the `ScopeData` into an `Arc` so it sticks around as long as we need it.
This means one extra `Arc::clone` per spawned scoped thread, which I hope is fine.
`Exclusive` is a wrapper that exclusively allows mutable access to the inner value if you have exclusive access to the wrapper. It acts like a compile time mutex, and hold an unconditional `Sync` implementation.
## Justification for inclusion into std
- This wrapper unblocks actual problems:
- The example that I hit was a vector of `futures::future::BoxFuture`'s causing a central struct in a script to be non-`Sync`. To work around it, you either write really difficult code, or wrap the futures in a needless mutex.
- Easy to maintain: this struct is as simple as a wrapper can get, and its `Sync` implementation has very clear reasoning
- Fills a gap: `&/&mut` are to `RwLock` as `Exclusive` is to `Mutex`
## Public Api
```rust
// core::sync
#[derive(Default)]
struct Exclusive<T: ?Sized> { ... }
impl<T> From<T> for Exclusive<T> { ... }
impl<T: ?Sized> Debug for Exclusive { ... }
```
## Naming
This is a big bikeshed, but I felt that `Exclusive` captured its general purpose quite well.
## Stability and location
As this is so simple, it can be in `core`. I feel that it can be stabilized quite soon after it is merged, if the libs teams feels its reasonable to add. Also, I don't really know how unstable feature work in std/core's codebases, so I might need help fixing them
## Tips for review
The docs probably are the thing that needs to be reviewed! I tried my best, but I'm sure people have more experience than me writing docs for `Core`
### Implementation:
The API is mostly pulled from https://docs.rs/sync_wrapper/latest/sync_wrapper/struct.SyncWrapper.html (which is apache 2.0 licenesed), and the implementation is trivial:
- its an unsafe justification for pinning
- its an unsafe justification for the `Sync` impl (mostly reasoned about by ````@danielhenrymantilla```` here: https://github.com/Actyx/sync_wrapper/pull/2)
- and forwarding impls, starting with derivable ones and `Future`
Yiming Lei [Wed, 29 Jun 2022 16:09:34 +0000 (09:09 -0700)]
For diagnostic information of Boolean, remind it as use the type: 'bool'
It helps programmers coming from other languages
modified: compiler/rustc_resolve/src/late/diagnostics.rs
bors [Thu, 30 Jun 2022 09:20:52 +0000 (09:20 +0000)]
Auto merge of #98377 - davidv1992:add-lifetimes-to-argument-temporaries, r=oli-obk
Added llvm lifetime annotations to function call argument temporaries.
The goal of this change is to ensure that llvm will do stack slot
optimization on these temporaries. This ensures that in code like:
```rust
const A: [u8; 1024] = [0; 1024];
fn copy_const() {
f(A);
f(A);
}
```
we only use 1024 bytes of stack space, instead of 2048 bytes.
I am new to developing for the rust compiler, and as such not entirely sure, but I believe this should be sufficient to close #98156.
Also, this does not contain a test case to ensure this keeps working, primarily because I am not sure how to go about testing this. I would love some suggestions as to how that could be approached.
bors [Thu, 30 Jun 2022 04:04:08 +0000 (04:04 +0000)]
Auto merge of #8666 - Jarcho:while_let_loop_7913, r=dswij
Don't lint `while_let_loop` when significant drop order would change
fixes #7226
fixes #7913
fixes #5717
For #5717 it may not stay fully fixed. This is only completely fixed right now due to all the allowed drop impls have `#[may_dangle]` on their drop impls. This may get changed in the future based on how significant drops are determined, but the example listed with `RefCell` shouldn't break.
changelog: Don't lint `while_let_loop` when the order of significant drops would change
bors [Thu, 30 Jun 2022 03:50:35 +0000 (03:50 +0000)]
Auto merge of #98649 - RalfJung:guardians-of-mir, r=oli-obk
move MIR syntax into a dedicated file and ping some people whenever it changes
Adding or changing MIR operations/statements/whatever should be under significant scrutiny wrt their wider impact, specified semantics, and so on. So let's start by putting all that into a dedicated file and pinging some people whenever that file changes.
This PR only moves definitions around, and then fiddles with imports until it all works again.
bors [Thu, 30 Jun 2022 01:02:24 +0000 (01:02 +0000)]
Auto merge of #98691 - matthiaskrgr:rollup-ymsa64p, r=matthiaskrgr
Rollup of 6 pull requests
Successful merges:
- #96727 (Make TAIT behave exactly like RPIT)
- #98681 (rustdoc-json: Make default value of blanket impl assoc types work)
- #98682 (add tests for ICE 94432)
- #98683 (add test for ice 68875)
- #98685 (Replace `sort_modules_alphabetically` boolean with enum)
- #98687 (add test for 47814)
Matthias Krüger [Wed, 29 Jun 2022 22:23:54 +0000 (00:23 +0200)]
Rollup merge of #98685 - camelid:sorting-flag, r=GuillaumeGomez
Replace `sort_modules_alphabetically` boolean with enum
This fixes the long-standing FIXME there and makes the code easier to
understand. The reference to modules in both the old and new names seems
potentially wrong since I believe it applies to all items.
This makes type-alias-impl-trait behave like return-position-impl-trait. Unfortunately it also causes some cases to stop compiling due to "needing type annotations" and makes panicking cause fallback for the hidden type to `()`.
All of these are addressable, but we should probably address them for RPIT and TAIT together
Noah Lev [Wed, 29 Jun 2022 20:04:43 +0000 (13:04 -0700)]
Replace `sort_modules_alphabetically` boolean with enum
This fixes the long-standing FIXME there and makes the code easier to
understand. The reference to modules in both the old and new names seems
potentially wrong since I believe it applies to all items.
bors [Wed, 29 Jun 2022 18:42:19 +0000 (18:42 +0000)]
Auto merge of #98680 - matthiaskrgr:rollup-1bkrrn9, r=matthiaskrgr
Rollup of 10 pull requests
Successful merges:
- #98434 (Ensure that `static_crt` is set in the bootstrapper whenever using `cc-rs` to get a compiler command line.)
- #98636 (Triagebot: Fix mentions word wrapping.)
- #98642 (Fix #98260)
- #98643 (Improve pretty printing of valtrees for references)
- #98646 (rustdoc: fix bugs in main.js popover help and settings)
- #98647 (Update cargo)
- #98652 (`alloc`: clean and ensure `no_global_oom_handling` builds are warning-free)
- #98660 (Unbreak stage1 tests via ignore-stage1 in `proc-macro/invalid-punct-ident-1.rs`.)
- #98665 (Use verbose help for deprecation suggestion)
- #98668 (Avoid some `&str` to `String` conversions with `MultiSpan::push_span_label`)
Matthias Krüger [Wed, 29 Jun 2022 18:35:05 +0000 (20:35 +0200)]
Rollup merge of #98660 - eddyb:invalid-punct-stage1, r=lqd
Unbreak stage1 tests via ignore-stage1 in `proc-macro/invalid-punct-ident-1.rs`.
#98188 broke `./x.py test --stage 1` (which I thought we ran in PR CI, cc `@rust-lang/infra)` i.e. the default `./x.py test` in dev checkouts, as the panic in `src/test/ui/proc-macro/invalid-punct-ident-1.rs` moved from the server (`rustc`) to the client (proc macro), and that means it's now affected by #59998.
I made the test look like `src/test/ui-fulldeps/issue-76270-panic-in-libproc-macro.rs` tho I'm a bit confused why that one is in `src/test/ui-fulldeps`, it should still work in `src/test/ui`, no? (cc `@Aaron1011)`
warning: associated function `shrink` is never used
--> library/alloc/src/raw_vec.rs:424:8
|
424 | fn shrink(&mut self, cap: usize) -> Result<(), TryReserveError> {
| ^^^^^^
|
= note: `#[warn(dead_code)]` on by default
warning: associated function `forget_remaining_elements` is never used
--> library/alloc/src/vec/into_iter.rs:126:19
|
126 | pub(crate) fn forget_remaining_elements(&mut self) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^
```
</details>
This PR cleans them and ensures no new ones are introduced
so that projects compiling `alloc` without infallible allocations
do not see them (and may want to enable `-Dwarnings`).
The couple `dead_code` ones may be reverted when some fallible
allocation support starts using them.
Matthias Krüger [Wed, 29 Jun 2022 18:34:59 +0000 (20:34 +0200)]
Rollup merge of #98636 - ehuss:mentions-wrapping, r=Mark-Simulacrum
Triagebot: Fix mentions word wrapping.
I forgot that GitHub's markdown treats newlines as hard breaks. This was causing some ugly-looking word wrapping in the triagebot mention messages. This fixes it so that the lines are not hard-wrapped.
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