Remove unreachable panics from VecDeque::{front/back}[_mut]
`VecDeque`'s `front`, `front_mut`, `back` and `back_mut` methods are implemented in terms of the index operator, which causes these functions to contain [unreachable panic calls](https://rust.godbolt.org/z/MTnq1o).
This PR reimplements these methods in terms of `get[_mut]` instead.
Don't try to add nested predicate to Rustdoc auto-trait `ParamEnv`
Fixes#80233
We already have logic in `evaluate_predicates` that tries to add
unimplemented predicates to our `ParamEnv`. Trying to add a predicate
that already holds can lead to errors later on, since projection
will prefer trait candidates from the `ParamEnv` to predicates from an
impl.
Update RLS and Rustfmt
Fixes#80576
Updates Rustfmt to use `rustfmt-v1.4.31` branch. Both are updated (along with `racer`) in tandem to pull in the exact same version of rustc-ap-* libraries.
r? `@calebcartwright`
Update books
## nomicon
2 commits in a5a48441d411f61556b57d762b03d6874afe575d..a8584998eacdea7106a1dfafcbf6c1c06fcdf925
2020-12-06 10:39:41 +0900 to 2021-01-06 12:49:49 -0500
- Update vector code examples
- Remove outdated information about `jemalloc`
## reference
13 commits in b278478b766178491a8b6f67afa4bcd6b64d977a..50af691f838937c300b47812d0507c6d88c14f97
2020-12-21 18:18:03 -0800 to 2021-01-12 21:19:20 -0800
- Update grammar for parser unification. (rust-lang/reference#927)
- Define constraining an implementation (rust-lang/reference#928)
- Document extra behavior of #[no_mangle] (rust-lang/reference#930)
- Add a float examle without a `.`. (rust-lang/reference#929)
- Add more details about const generics. (rust-lang/reference#921)
- Fix footnotes. (rust-lang/reference#926)
- Add "Logic errors" as behavior not considered unsafe (rust-lang/reference#919)
- Update grammar for order of parameters/arguments. (rust-lang/reference#920)
- Fix formatting in the tuple section (rust-lang/reference#923)
- document const generics (rust-lang/reference#901)
- Update mdbook (rust-lang/reference#918)
- linkage.md: update link to FFI section of the Book. (rust-lang/reference#917)
- Document array expression with a const. (rust-lang/reference#914)
## book
8 commits in 5bb44f8b5b0aa105c8b22602e9b18800484afa21..ac57a0ddd23d173b26731ccf939f3ba729753275
2020-12-18 20:07:31 -0500 to 2021-01-09 14:18:45 -0500
- Update version of mdbook we're testing with to 0.4.5 (rust-lang/book#2561)
- Fix grammar in ch13-01-closures.md (rust-lang/book#2534)
- Merge remote-tracking branch 'origin/pr/2527'
- Clarify code example ch6.3 (rust-lang/book#2485)
- Fix link added in rust-lang/book#2495 to be relative and at the bottom
- Merge remote-tracking branch 'origin/pr/2495'
- Update output to match the updated poem punctuation
- Fixrust-lang/book#2539 - Remove fancy apostrophes from poem for Windows
## rust-by-example
3 commits in 1cce0737d6a7d3ceafb139b4a206861fb1dcb2ab..03e23af01f0b4f83a3a513da280e1ca92587f2ec
2020-12-21 17:36:29 -0300 to 2021-01-09 10:20:28 -0300
- Replace for loop with iteration (rust-lang/rust-by-example#1404)
- Update mdbook (rust-lang/rust-by-example#1402)
- Add note for match guards to include catch-all (rust-lang/rust-by-example#1401)
## embedded-book
1 commits in ba34b8a968f9531d38c4dc4411d5568b7c076bfe..ceec19e873be87c6ee5666b030c6bb612f889a96
2020-11-17 00:20:43 +0000 to 2021-01-03 13:13:10 +0000
- book.toml: add link to GitHub repo (rust-embedded/book#276)
Update tests of "unused_lifetimes" lint for async functions and corresponding source code
Before this PR the following code would cause an error:
```
#![deny(unused_lifetimes)]
async fn f<'a>(_: &'a i32) {}
fn main() {}
```
It was happening because of the desugaring of return type in async functions. As a result of the desugaring, the return type contains all lifetimes involved in the function signature. And these lifetimes were interpreted separately from the same in the function scope => so they are unused.
Now, all lifetimes from the return type are interpreted as used. It is also not perfect, but at least this lint doesn't cause wrong errors now.
This PR connected to issues #78522, #77217
Box Item::Attributes
This reduces the size of Item from 128 to 40 bytes. I think this is as small as it needs to get 🎉
Builds on https://github.com/rust-lang/rust/pull/80339 and should not be merged before.
r? `@GuillaumeGomez`
Properly handle `SyntaxContext` of dummy spans in incr comp
Fixes#80336
Due to macro expansion, we may end up with spans with an invalid
location and non-root `SyntaxContext`. This commits preserves the
`SyntaxContext` of such spans in the incremental cache, and ensures
that we always hash the `SyntaxContext` when computing the `Fingerprint`
of a `Span`
Previously, we would discard the `SyntaxContext` during serialization to
the incremental cache, causing the span's `Fingerprint` to change across
compilation sessions.
Rework diagnostics for wrong number of generic args (fixes#66228 and #71924)
This PR reworks the `wrong number of {} arguments` message, so that it provides more details and contextual hints.
Fixes#80336
Due to macro expansion, we may end up with spans with an invalid
location and non-root `SyntaxContext`. This commits preserves the
`SyntaxContext` of such spans in the incremental cache, and ensures
that we always hash the `SyntaxContext` when computing the `Fingerprint`
of a `Span`
Previously, we would discard the `SyntaxContext` during serialization to
the incremental cache, causing the span's `Fingerprint` to change across
compilation sessions.
Stabilize split_inclusive
### Contents of this MR
This stabilises:
* `slice::split_inclusive`
* `slice::split_inclusive_mut`
* `str::split_inclusive`
Closes#72360.
### A possible concern
The proliferation of `split_*` methods is not particularly pretty. The existence of `split_inclusive` seems to invite the addition of `rsplit_inclusive`, `splitn_inclusive`, etc. We could instead have a more general API, along these kinds of lines maybe:
```
pub fn split_generic('a,P,H>(&'a self, pat: P, how: H) -> ...
where P: Pattern
where H: SplitHow;
pub fn split_generic_mut('a,P,H>(&'a mut self, pat: P, how: H) -> ...
where P: Pattern
where H: SplitHow;
trait SplitHow {
fn reverse(&self) -> bool;
fn inclusive -> bool;
fn limit(&self) -> Option<usize>;
}
pub struct SplitFwd;
...
pub struct SplitRevInclN(pub usize);
```
But maybe that is worse.
### Let us defer that? ###
This seems like a can of worms. I think we can defer opening it now; if and when we have something more general, these two methods can become convenience aliases. But I thought I would mention it so the lang API team can consider it and have an opinion.
For example, this code:
struct S(i32, f32);
let S(x) = S(0, 1.0);
will make the compiler suggest either:
let S(x, _) = S(0, 1.0);
or:
let S(x, ..) = S(0, 1.0);
Fix rustdoc --test-builder argument parsing
My suggested fix to issue #80893. I can actually hook Miri in there now.
I also fixed what I believe to be a typo in the option's help text.
Fix --pretty=expanded with --remap-path-prefix
Per https://github.com/rust-lang/rust/issues/80832, using
--pretty=expanded and --remap-path-prefix results in an ICE.
This is becasue the session source files table is stored in remapped
form, whereas --pretty-expanded looks up unremapped files. This remaps
the path prefixes before lookup.
~~There don't appear to be any existing tests for --pretty=expanded; I'll look into
adding some.~~ Never mind, found the pretty tests.
Fixes#80832
Update to LLVM 11.0.1
This updates to a new LLVM branch, rebased on the upstream `llvmorg-11.0.1`. All our patches applied cleanly except the fortanix unwind changes, which just needed a small adjustment in cmake files.
r? `@nikic`
Fixes https://github.com/rust-lang/rust/issues/73722
Separate out a `hir::Impl` struct
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
See `rustc_save_analysis::dump_visitor::process_impl` or `rustdoc::clean::clean_impl` for a good example of how this makes `impl`s easier to work with.
r? `@petrochenkov` maybe?
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
Turn type inhabitedness into a query to fix `exhaustive_patterns` perf
We measured in https://github.com/rust-lang/rust/pull/79394 that enabling the [`exhaustive_patterns` feature](https://github.com/rust-lang/rust/issues/51085) causes significant perf degradation. It was conjectured that the culprit is type inhabitedness checking, and [I hypothesized](https://github.com/rust-lang/rust/pull/79394#issuecomment-733861149) that turning this computation into a query would solve most of the problem.
This PR turns `tcx.is_ty_uninhabited_from` into a query, and I measured a 25% perf gain on the benchmark that stress-tests `exhaustiveness_patterns`. This more than compensates for the 30% perf hit I measured [when creating it](https://github.com/rust-lang/rustc-perf/pull/801). We'll have to measure enabling the feature again, but I suspect this fixes the perf regression entirely.
I'd like a perf run on this PR obviously.
I made small atomic commits to help reviewing. The first one is just me discovering the "revisions" feature of the testing framework.
I believe there's a push to move things out of `rustc_middle` because it's huge. I guess `inhabitedness/mod.rs` could be moved out, but it's quite small. `DefIdForest` might be movable somewhere too. I don't know what the policy is for that.
Ping `@camelid` since you were interested in following along
`@rustbot` modify labels: +A-exhaustiveness-checking
Make CTFE able to check for UB...
... by not doing any optimizations on the `const fn` MIR used in CTFE. This means we duplicate all `const fn`'s MIR now, once for CTFE, once for runtime. This PR is for checking the perf effect, so we have some data when talking about https://github.com/rust-lang/const-eval/blob/master/rfcs/0000-const-ub.md
To do this, we now have two queries for obtaining mir: `optimized_mir` and `mir_for_ctfe`. It is now illegal to invoke `optimized_mir` to obtain the MIR of a const/static item's initializer, an array length, an inline const expression or an enum discriminant initializer. For `const fn`, both `optimized_mir` and `mir_for_ctfe` work, the former returning the MIR that LLVM should use if the function is called at runtime. Similarly it is illegal to invoke `mir_for_ctfe` on regular functions.
This is all checked via appropriate assertions and I don't think it is easy to get wrong, as there should be no `mir_for_ctfe` calls outside the const evaluator or metadata encoding. Almost all rustc devs should keep using `optimized_mir` (or `instance_mir` for that matter).
