bors [Sat, 4 Jun 2022 11:29:29 +0000 (11:29 +0000)]
Auto merge of #97729 - Dylan-DPC:rollup-dv43xo9, r=Dylan-DPC
Rollup of 5 pull requests
Successful merges:
- #96642 (Avoid zero-sized allocs in ThinBox if T and H are both ZSTs.)
- #97647 (Lazily allocate and initialize pthread locks.)
- #97715 (Support the `#[expect]` attribute on fn parameters (RFC-2383))
- #97716 (Fix reachability analysis for const methods)
- #97722 (Tighten spans for bad fields in struct deriving `Copy`)
Dylan DPC [Sat, 4 Jun 2022 09:06:40 +0000 (11:06 +0200)]
Rollup merge of #97647 - m-ou-se:lazy-box-locks, r=Amanieu
Lazily allocate and initialize pthread locks.
Lazily allocate and initialize pthread locks.
This allows {Mutex, Condvar, RwLock}::new() to be const, while still using the platform's native locks for features like priority inheritance and debug tooling. E.g. on macOS, we cannot directly use the (private) APIs that pthread's locks are implemented with, making it impossible for us to use anything other than pthread while still preserving priority inheritance, etc.
This PR doesn't yet make the public APIs const. That's for a separate PR with an FCP.
Dylan DPC [Sat, 4 Jun 2022 09:06:39 +0000 (11:06 +0200)]
Rollup merge of #96642 - thomcc:thinbox-zst-ugh, r=yaahc
Avoid zero-sized allocs in ThinBox if T and H are both ZSTs.
This was surprisingly tricky, and took longer to get right than expected. `ThinBox` is a surprisingly subtle piece of code. That said, in the end, a lot of this was due to overthinking[^overthink] -- ultimately the fix ended up fairly clean and simple.
[^overthink]: Honestly, for a while I was convinced this couldn't be done without allocations or runtime branches in these cases, but that's obviously untrue.
Anyway, as a result of spending all that time debugging, I've extended the tests quite a bit, and also added more debug assertions. Many of these helped for subtle bugs I made in the middle (for example, the alloc/drop tracking is because I ended up double-dropping the value in the case where both were ZSTs), they're arguably a bit of overkill at this point, although I imagine they could help in the future too.
Anyway, these tests cover a wide range of size/align cases, nd fully pass under miri[^1]. They also do some smoke-check asserting that the value has the correct alignment, although in practice it's totally within the compiler's rights to delete these assertions since we'd have already done UB if they get hit. They have more boilerplate than they really need, but it's not *too* bad on a per-test basis.
A notable absence from testing is atypical header types, but at the moment it's impossible to manually implement `Pointee`. It would be really nice to have testing here, since it's not 100% obvious to me that the aligned read/write we use for `H` are correct in the face of arbitrary combinations of `size_of::<H>()`, `align_of::<H>()`, and `align_of::<T>()`. (That said, I spent a while thinking through it and am *pretty* sure it's fine -- I'd just feel... better if we could test some cases for non-ZST headers which have unequal and align).
[^1]: Or at least, they pass under miri if I copy the code and tests into a new crate and run miri on it (after making it less stdlibified).
Fixes #96485.
I'd request review ``@yaahc,`` but I believe you're taking some time away from reviews, so I'll request from the previous PR's reviewer (I think that the context helps, even if the actual change didn't end up being bad here).
bors [Sat, 4 Jun 2022 02:10:35 +0000 (02:10 +0000)]
Auto merge of #97717 - matthiaskrgr:rollup-lalaii2, r=matthiaskrgr
Rollup of 5 pull requests
Successful merges:
- #97446 (Make hir().get_generics and generics_of consistent.)
- #97656 (Add a suggestion to replace parentheses with angle brackets on associated trait constraint)
- #97692 (Add `#T-types/nominated` zulip notification)
- #97696 (Do not ICE when failing to normalize during inlining.)
- #97702 (Remove useless LocalDefId in ImplTraitContext::Universal.)
bors [Fri, 3 Jun 2022 23:29:30 +0000 (23:29 +0000)]
Auto merge of #97670 - spastorino:simplify-universal-impl-trait-lowering2, r=Dylan-DPC
Make params be SmallVec as originally was
r? `@cjgillot`
It was originally a [`SmallVec`](https://github.com/rust-lang/rust/pull/97598/files#diff-0a61b538a3cec072c76fecae4635af6a12ec3256860029ac70549c2aa53ab394L1497), I've mistakenly changed it [here](https://github.com/rust-lang/rust/pull/97598/files#diff-0a61b538a3cec072c76fecae4635af6a12ec3256860029ac70549c2aa53ab394R1377) to a `Vec`
Matthias Krüger [Fri, 3 Jun 2022 22:42:50 +0000 (00:42 +0200)]
Rollup merge of #97656 - EdwinRy:error_ast_low_type_contraint_parentheses, r=cjgillot
Add a suggestion to replace parentheses with angle brackets on associated trait constraint
This implements a requested suggestion FIXME in [`compiler/rustc_ast_lowering/src/lib.rs` ](https://github.com/rust-lang/rust/blob/9598b4b594c97dff66feb93522e22db500deea07/compiler/rustc_ast_lowering/src/lib.rs#L921)
The suggestion asks for the parentheses to either be replaced with angle brackets or removed completely depending on whether there are arguments provided within.
Matthias Krüger [Fri, 3 Jun 2022 22:42:49 +0000 (00:42 +0200)]
Rollup merge of #97446 - cjgillot:get-generics, r=michaelwoerister
Make hir().get_generics and generics_of consistent.
Fetching generics from a HIR node is currently implemented differently in 4 different places.
This PR makes the 4 implementations call the single `hir::Node::generics`, which implements the more general version from `generics_of` query.
bors [Fri, 3 Jun 2022 17:55:02 +0000 (17:55 +0000)]
Auto merge of #85993 - bjorn3:serde_json, r=wesleywiser
Remove all json handling from rustc_serialize
Json is now handled using serde_json. Where appropriate I have replaced json usage with binary serialization (rmeta files) or manual string formatting (emcc linker arg generation).
This allowed for removing and simplifying a lot of code, which hopefully results in faster serialization/deserialization and faster compiles of rustc itself.
Where sensible we now use serde. Metadata and incr cache serialization keeps using a heavily modified (compared to crates.io) rustc-serialize version that in the future could probably be extended with zero-copy deserialization or other perf tricks that serde can't support due to supporting more than one serialization format.
Note that I had to remove `-Zast-json` and `-Zast-json-noexpand` as the relevant AST types don't implement `serde::Serialize`.
Fixes #40177
See also https://github.com/rust-lang/compiler-team/issues/418
Dylan DPC [Fri, 3 Jun 2022 15:10:51 +0000 (17:10 +0200)]
Rollup merge of #97415 - cjgillot:is-late-bound-solo, r=estebank
Compute `is_late_bound_map` query separately from lifetime resolution
This query is actually very simple, and is only useful for functions and method. It can be computed directly by fetching the HIR, with no need to embed it within the lifetime resolution visitor.
Based on https://github.com/rust-lang/rust/pull/96296
bors [Fri, 3 Jun 2022 12:37:16 +0000 (12:37 +0000)]
Auto merge of #89862 - lcnr:path-generics-diagnostics, r=estebank
rewrite error handling for unresolved inference vars
Pretty much completely rewrites `fn emit_inference_failure_err`.
This new setup should hopefully be easier to extend and is already a lot better when looking for generic arguments.
Because this is a rewrite there are still some parts which are lacking, these are tracked in #94483 and will be fixed in later PRs.
Dylan DPC [Fri, 3 Jun 2022 09:18:26 +0000 (11:18 +0200)]
Rollup merge of #97664 - estebank:suggest-bound-derive-copy, r=compiler-errors
On E0204 suggest missing type param bounds
```
error[E0204]: the trait `Copy` may not be implemented for this type
--> f42.rs:9:17
|
9 | #[derive(Debug, Copy, Clone)]
| ^^^^
10 | pub struct AABB<K>{
11 | pub loc: Vector2<K>,
| ------------------- this field does not implement `Copy`
12 | pub size: Vector2<K>
| -------------------- this field does not implement `Copy`
|
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:11:5
|
11 | pub loc: Vector2<K>,
| ^^^^^^^^^^^^^^^^^^^
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:12:5
|
12 | pub size: Vector2<K>
| ^^^^^^^^^^^^^^^^^^^^
= note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `K`
|
10 | pub struct AABB<K: Debug>{
| +++++++
```
bors [Fri, 3 Jun 2022 07:27:09 +0000 (07:27 +0000)]
Auto merge of #96296 - cjgillot:remove-label-lt-shadow, r=petrochenkov
Remove label/lifetime shadowing warnings
This PR removes some pre-1.0 shadowing warnings for labels and lifetimes.
The current behaviour of the compiler is to warn
* labels that shadow unrelated labels in the same function --> removed
```rust
'a: loop {}
'a: loop {} // STOP WARNING
```
* labels that shadow enclosing labels --> kept, but only if shadowing is hygienic
```rust
'a: loop {
'a: loop {} // KEEP WARNING
}
```
From `@petrochenkov` in https://github.com/rust-lang/rust/pull/95781#issuecomment-1105199014
> I think we should remove these silly checks entirely.
> They were introduced long time ago in case some new language features appear and require this space.
> Now we have another mechanism for such language changes - editions, and if "lifetimes in expressions" or something like that needs to be introduced it could be introduced as an edition change.
> However, there was no plans to introduce anything like for years, so it's unlikely that even the edition mechanism will be necessary.
bors [Fri, 3 Jun 2022 00:21:29 +0000 (00:21 +0000)]
Auto merge of #97667 - matthiaskrgr:rollup-5cfxc85, r=matthiaskrgr
Rollup of 5 pull requests
Successful merges:
- #97502 (rustdoc: Add more test coverage)
- #97627 (update explicit impls error msg)
- #97640 (Fix wrong suggestion for adding where clauses)
- #97645 (don't use a `span_note` for ignored impls)
- #97655 (Improve documentation for constructors of pinned `Box`es)
Matthias Krüger [Thu, 2 Jun 2022 21:39:07 +0000 (23:39 +0200)]
Rollup merge of #97655 - steffahn:better-pin-box-construction-docs, r=thomcc
Improve documentation for constructors of pinned `Box`es
Adds a cross-references between `Box::pin` and `Box::into_pin` (and other related methods, i.e. the equivalent `From` implementation, and the unstable `pin_in` method), in particular now that `into_pin` [was stabilized](https://github.com/rust-lang/rust/pull/97397). The main goal is to further improve visibility of the fact that `Box<T> -> Pin<Box<T>>` conversion exits in the first place, and that `Box::pin(x)` is – essentially – just a convenience function for `Box::into_pin(Box::new(x))`
The motivating context why I think this is important is even experienced Rust users overlooking the existence this kind of conversion, [e.g. in this thread on IRLO](https://internals.rust-lang.org/t/pre-rfc-function-variants/16732/7?u=steffahn); and also the fact that that discussion brought up that there would be a bunch of Box-construction methods "missing" such as e.g. methods with fallible allocation a la "`Box::try_pin`", and similar; while those are in fact *not* necessary, because you can use `Box::into_pin(Box::try_new(x)?)` instead.
I have *not* included explicit mention of methods (e.g. `try_new`) in the docs of stable methods (e.g. `into_pin`). (Referring to unstable API in stable API docs would be bad style IMO.) Stable examples I have in mind with the statement "constructing a (pinned) Box in a different way than with `Box::new`" are things like cloning a `Box`, or `Box::from_raw`. If/when `try_new` would get stabilized, it would become a very good concrete example use-case of `Box::into_pin` IMO.
Matthias Krüger [Thu, 2 Jun 2022 21:39:06 +0000 (23:39 +0200)]
Rollup merge of #97645 - lcnr:derived-impl-debug, r=cjgillot
don't use a `span_note` for ignored impls
Searching for the `derive` isn't too difficult as it's right above the field definition.
By using a span these errors are a lot more verbose than they should be, which is especially annoying as one can end up with a lot of `dead_code` warnings.
Esteban Küber [Thu, 2 Jun 2022 19:34:55 +0000 (12:34 -0700)]
On E0204 suggest missing type param bounds
```
error[E0204]: the trait `Copy` may not be implemented for this type
--> f42.rs:9:17
|
9 | #[derive(Debug, Copy, Clone)]
| ^^^^
10 | pub struct AABB<K>{
11 | pub loc: Vector2<K>,
| ------------------- this field does not implement `Copy`
12 | pub size: Vector2<K>
| -------------------- this field does not implement `Copy`
|
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:11:5
|
11 | pub loc: Vector2<K>,
| ^^^^^^^^^^^^^^^^^^^
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:12:5
|
12 | pub size: Vector2<K>
| ^^^^^^^^^^^^^^^^^^^^
= note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `K`
|
10 | pub struct AABB<K: Debug>{
| +++++++
```
bors [Thu, 2 Jun 2022 18:45:29 +0000 (18:45 +0000)]
Auto merge of #97575 - nnethercote:lazify-SourceFile-lines, r=Mark-Simulacrum
Lazify `SourceFile::lines`.
`SourceFile::lines` is a big part of metadata. It's stored in a compressed form
(a difference list) to save disk space. Decoding it is a big fraction of
compile time for very small crates/programs.
This commit introduces a new type `SourceFileLines` which has a `Lines`
form and a `Diffs` form. The latter is used when the metadata is first
read, and it is only decoded into the `Lines` form when line data is
actually needed. This avoids the decoding cost for many files,
especially in `std`. It's a performance win of up to 15% for tiny
crates/programs where metadata decoding is a high part of compilation
costs.
A `RefCell` is needed because the methods that access lines data (which can
trigger decoding) take `&self` rather than `&mut self`. To allow for this,
`SourceFile::lines` now takes a `FnMut` that operates on the lines slice rather
than returning the lines slice.
Dylan DPC [Thu, 2 Jun 2022 13:27:01 +0000 (15:27 +0200)]
Rollup merge of #97636 - nnethercote:revert-96682, r=dtolnay
Revert #96682.
The change was "Show invisible delimiters (within comments) when pretty
printing". It's useful to show these delimiters, but is a breaking
change for some proc macros.
The problem was that the ID was conflicting because the reexports have the same one. To fix it, I "extended" it by adding the `Symbol` into it as well.
Dylan DPC [Thu, 2 Jun 2022 13:26:58 +0000 (15:26 +0200)]
Rollup merge of #97450 - c410-f3r:assert-compiler, r=oli-obk
[RFC 2011] Basic compiler infrastructure
Splitting https://github.com/rust-lang/rust/pull/96496 into smaller pieces as was done in https://github.com/rust-lang/rust/pull/97233. Hope review will be easier.
This PR practically contains no logic and only serves as a building ground for the actual code that will be placed in a posterior step.
* Adds `context.rs` to place the new `assert!` logic. Has a lot of unused elements but all of them are used by the implementation.
* Creates an unstable flag because the feature is not yet complete and also to allow external feedback.
* Creates the necessary `sym` identifiers that are mostly based on the library elements -> https://github.com/rust-lang/rust/blob/master/library/core/src/asserting.rs
* Modifies `assert.rs` to branch to `context.rs` if the unstable flag is enabled.
* Adds a test to satisfy tidy but the test does nothing in reality.
bors [Thu, 2 Jun 2022 13:20:19 +0000 (13:20 +0000)]
Auto merge of #97293 - est31:remove_box, r=oli-obk
Add #[rustc_box] and use it inside alloc
This commit adds an alternative content boxing syntax, and uses it inside alloc.
```Rust
#![feature(box_syntax)]
fn foo() {
let foo = box bar;
}
```
is equivalent to
```Rust
#![feature(rustc_attrs)]
fn foo() {
let foo = #[rustc_box] Box::new(bar);
}
```
The usage inside the very performance relevant code in
liballoc is the only remaining relevant usage of box syntax
in the compiler (outside of tests, which are comparatively easy to port).
box syntax was originally designed to be used by all Rust
developers. This introduces a replacement syntax more tailored
to only being used inside the Rust compiler, and with it,
lays the groundwork for eventually removing box syntax.
[Earlier work](https://github.com/rust-lang/rust/pull/87781#issuecomment-894714878) by `@nbdd0121` to lower `Box::new` to `box` during THIR -> MIR building ran into borrow checker problems, requiring the lowering to be adjusted in a way that led to [performance regressions](https://github.com/rust-lang/rust/pull/87781#issuecomment-894872367). The proposed change in this PR lowers `#[rustc_box] Box::new` -> `box` in the AST -> HIR lowering step, which is way earlier in the compiler, and thus should cause less issues both performance wise as well as regarding type inference/borrow checking/etc. Hopefully, future work can move the lowering further back in the compiler, as long as there are no performance regressions.