Mara Bos [Sun, 27 Jun 2021 12:41:50 +0000 (12:41 +0000)]
Add #[track_caller] for some function in core::mem.
These functions can panic for some types. This makes the panic point to
the code that calls e.g. mem::uninitialized(), instead of inside the
definition of mem::uninitialized.
Auto merge of #86251 - Smittyvb:thir-tree-again, r=oli-obk
Support -Z unpretty=thir-tree again
Currently `-Z unpretty=thir-tree` is broken after some THIR refactorings. This re-implements it, making it easier to debug THIR-related issues.
We have to do analyzes before getting the THIR, since trying to create THIR from invalid HIR can ICE. But doing those analyzes requires the THIR to be built and stolen. We work around this by creating a separate query to construct the THIR tree string representation.
Auto merge of #86735 - jhpratt:rfc-3107, r=petrochenkov
Implement RFC 3107: `#[derive(Default)]` on enums with a `#[default]` attribute
This PR implements RFC 3107, which permits `#[derive(Default)]` on enums where a unit variant has a `#[default]` attribute. See comments for current status.
Auto merge of #85769 - jhpratt:stabilize-const-transmute-union, r=RalfJung
Stabilize `const_fn_transmute`, `const_fn_union`
This PR stabilizes the `const_fn_transmute` and `const_fn_union` features. It _does not_ stabilize any methods (obviously aside from `transmute`) that are blocked on only these features.
Auto merge of #80367 - camelid:check_match-combine-loop, r=Nadrieril
Combine two loops in `check_match`
Suggested by Nadrieril in
https://github.com/rust-lang/rust/pull/79051#discussion_r548778186.
Opening to get a perf run. Hopefully this code doesn't require everything in the
first loop to be done before running the second! (It shouldn't though.)
17 commits in eac55314210519238652f12b30fec9daea61f7fe..a07036f864b37896b31eb996cd7aedb489f69a1f
2021-07-19 11:08:01 -0400 to 2021-07-26 20:19:46 -0400
- Set expectations a bit more realistically
- Snapshot of chapter 4 for nostarch
- A few small wording tweaks in ch 4
- Clarify that it's not stack/heap exactly that matters for copy/non copy, fixes rust-lang/book#2799
- Clarify a detail around move. Fixes rust-lang/book#2413.
- Clarify places that changed because of NLL. Fixes rust-lang/book#1939.
- nostarch ch3
- Small edits to chapter 3
- (rust-lang/book#2797)
- Update ch03-03-how-functions-work.md: Pervasive -> Prevalent. (rust-lang/book#2796)
- Address loop labels and continue. Fixes rust-lang/book#1392.
- Clarify behavior of integer division. Fixes rust-lang/book#2248.
- Demonstrate how scope interacts with shadowing
- Add another cross-reference to the new unit type introduction
- Introduce the unit type with tuples. Fixes rust-lang/book#1933.
- Reword sentence to not have numbers separated only by a comma
- Link directly to other installation page. Fixes rust-lang/book#1609
Rollup merge of #87502 - ehuss:update-cargo, r=ehuss
Update cargo
8 commits in cebef2951ee69617852844894164b54ed478a7da..d21c22870e58499d6c31f1bef3bf1255eb021666
2021-07-22 13:01:52 +0000 to 2021-07-26 20:23:21 +0000
- Fix version string. (rust-lang/cargo#9727)
- Allow publishing from workspace root. (rust-lang/cargo#9559)
- Better msg for wrong position (rust-lang/cargo#9723)
- Stabilize the rustc-link-arg option (rust-lang/cargo#9557)
- Warning when using features in replace (rust-lang/cargo#9681)
- Refactor if let chains to matches! macro (rust-lang/cargo#9721)
- Weather is not nice today.. (rust-lang/cargo#9720)
- Update should_use_metadata function (rust-lang/cargo#9653)
Rollup merge of #86450 - tmiasko:move-size-limit, r=pnkfelix
Add flag to configure `large_assignments` lint
The `large_assignments` lints detects moves over specified limit. The
limit is configured through `move_size_limit = "N"` attribute placed at
the root of a crate. When attribute is absent, the lint is disabled.
Make it possible to enable the lint without making any changes to the
source code, through a new flag `-Zmove-size-limit=N`. For example, to
detect moves exceeding 1023 bytes in a cargo crate, including all
dependencies one could use:
Auto merge of #87431 - the8472:array-iter-fold, r=kennytm
implement fold() on array::IntoIter to improve flatten().collect() perf
With #87168 flattening `array::IntoIter`s is now `TrustedLen`, the `FromIterator` implementation for `Vec` has a specialization for `TrustedLen` iterators which uses internal iteration. This implements one of the main internal iteration methods on `array::Into` to optimize the combination of those two features.
This should address the main issue in #87411
```
# old
test vec::bench_flat_map_collect ... bench: 2,244,024 ns/iter (+/- 18,903)
# new
test vec::bench_flat_map_collect ... bench: 172,863 ns/iter (+/- 2,141)
```
Auto merge of #85305 - MarcusDunn:master, r=pnkfelix
Stabilize bindings_after_at
attempting to stabilze bindings_after_at [#65490](https://github.com/rust-lang/rust/issues/65490), im pretty new to the whole thing so any pointers are greatly appreciated.
Auto merge of #83491 - jyn514:remove-pretty, r=pnkfelix
Remove unstable `--pretty` flag
It doesn't do anything `--unpretty` doesn't, and due to a bug, also
didn't show up in `--help`. I don't think there's any reason to keep it
around, I haven't seen anyone using it.
Auto merge of #87062 - poliorcetics:fix-85462, r=dtolnay
Make StrSearcher behave correctly on empty needle
Fix #85462.
This will not affect ABI since the other variant of the enum is bigger.
It may break some code, but that would be very strange: usually people
don't continue after the first `Done` (or `None` for a normal iterator).
Auto merge of #87480 - GuillaumeGomez:rollup-3ly8t5d, r=GuillaumeGomez
Rollup of 8 pull requests
Successful merges:
- #87436 (Suggest `;` on parse error where applicable)
- #87444 (Flatten nested `format!` calls)
- #87447 (Miri: santiy check that null pointer can never have an AllocId)
- #87457 (freebsd remove compiler workaround.)
- #87458 (Fix help message for modification to &T created by &{t})
- #87464 (Remove unnecessary `structhead` parameter from `render_union`)
- #87473 (Notify the Rust 2021 edition working group in zulip of edition bugs)
- #87474 (Add missing whitespace after attribute in HTML template)
Rollup merge of #87464 - camelid:rm-union-structhead, r=jyn514
Remove unnecessary `structhead` parameter from `render_union`
`structhead` is used for `render_struct` so that the logic for rendering
structs can be shared between struct variants and struct items. However,
`render_union` is not used anywhere except for rendering union items, so
its `structhead` parameter is unnecessary.
Rollup merge of #87458 - ibraheemdev:help-msg-block-borrow, r=oli-obk
Fix help message for modification to &T created by &{t}
Previous:
```rust
error[E0594]: cannot assign to `*x` which is behind a `&` reference
--> src/main.rs:3:5
|
2 | let x: &usize = &mut{0};
| ------- help: consider changing this to be a mutable reference: `&mut mut{0}`
3 | *x = 1;
| ^^^^^^ `x` is a `&` reference, so the data it refers to cannot be written
```
Auto merge of #87439 - ThibsG:FixDocTypo, r=jonas-schievink
Fix doc typo
Just a typo in doc that has a bad rendering here: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_typeck/expr_use_visitor/struct.ExprUseVisitor.html#method.walk_captures
Noah Lev [Sun, 25 Jul 2021 23:28:52 +0000 (16:28 -0700)]
Remove unnecessary `structhead` parameter from `render_union`
`structhead` is used for `render_struct` so that the logic for rendering
structs can be shared between struct variants and struct items. However,
`render_union` is not used anywhere except for rendering union items, so
its `structhead` parameter is unnecessary.
Auto merge of #85646 - Moxinilian:separate-const-switch, r=cjgillot
MIR opt: separate constant predecessors of a switch
For each block S ending with a switch, this pass copies S for each of S's predecessors that seem to assign the value being switched over as a const. This is done using a somewhat simple heuristic to determine what seems to be a const transitively.
More precisely, this is what the pass does:
- find a block that ends in a switch
- track if there is an unique place set before the current basic block that determines the result of the switch (this is the part that resolves switching over discriminants)
- if there is, iterate over the parents that have a reasonable terminator and find if the found determining place is likely to be (transitively) set from a const within that parent block
- if so, add the corresponding edge to a vector of edges to duplicate
- once this is done, iterate over the found edges: copy the target block and replace the reference to the target block in the origin block with the new block
This pass is not optimal and could probably duplicate in more cases, but the intention was mostly to address cases like in #85133 or #85365, to avoid creating new enums that get destroyed immediately afterwards (notably making the new try v2 `?` desugar zero-cost).
A benefit of this pass working the way it does is that it is easy to ensure its correctness: the worst that can happen is for it to needlessly copy a basic block, which is likely to be destroyed by cleanup passes afterwards. The complex parts where aliasing matters are only heuristics and the hard work is left to further passes like ConstProp.
# LLVM blocker
Unfortunately, I believe it would be unwise to enable this optimization by default for now. Indeed, currently switch lowering passes like SimplifyCFG in LLVM lose the information on the set of possible variant values, which means it tends to actually generate worse code with this optimization enabled. A fix would have to be done in LLVM itself. This is something I also want to look into. I have opened [a bug report at the LLVM bug tracker](https://bugs.llvm.org/show_bug.cgi?id=50455).
When this is done, I hope we can enable this pass by default. It should be fairly fast and I think it is beneficial in many cases. Notably, it should be a sound alternative to simplify-arm-identity. By the way, ConstProp only seems to pick up the optimization in functions that are not generic. This is however most likely an issue in ConstProp that I will look into afterwards.
This is my first contribution to rustc, and I would like to thank everyone on the Zulip mir-opt chat for the help and support, and especially `@scottmcm` for the guidance.
Auto merge of #87381 - Aaron1011:note-semi-trailing-macro, r=petrochenkov
Display an extra note for trailing semicolon lint with trailing macro
Currently, we parse macros at the end of a block
(e.g. `fn foo() { my_macro!() }`) as expressions, rather than
statements. This means that a macro invoked in this position
cannot expand to items or semicolon-terminated expressions.
In the future, we might want to start parsing these kinds of macros
as statements. This would make expansion more 'token-based'
(i.e. macro expansion behaves (almost) as if you just textually
replaced the macro invocation with its output). However,
this is a breaking change (see PR #78991), so it will require
further discussion.
Since the current behavior will not be changing any time soon,
we need to address the interaction with the
`SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` lint. Since we are parsing
the result of macro expansion as an expression, we will emit a lint
if there's a trailing semicolon in the macro output. However, this
results in a somewhat confusing message for users, since it visually
looks like there should be no problem with having a semicolon
at the end of a block
(e.g. `fn foo() { my_macro!() }` => `fn foo() { produced_expr; }`)
To help reduce confusion, this commit adds a note explaining
that the macro is being interpreted as an expression. Additionally,
we suggest adding a semicolon after the macro *invocation* - this
will cause us to parse the macro call as a statement. We do *not*
use a structured suggestion for this, since the user may actually
want to remove the semicolon from the macro definition (allowing
the block to evaluate to the expression produced by the macro).
Auto merge of #87331 - camelid:summary-escaping, r=GuillaumeGomez
Escape item search summaries
I noticed that `Pin::new()`'s search summary looked off, and I realized
that the reason is that it has inline code containing `Pin<P>`, which is
not escaped and thus renders as a paragraph tag!
Noah Lev [Mon, 5 Jul 2021 02:22:24 +0000 (19:22 -0700)]
Escape item search summaries
I noticed that `Pin::new()`'s search summary looked off, and I realized
that the reason is that it has inline code containing `Pin<P>`, which is
not escaped and thus renders as a paragraph tag!
Auto merge of #84111 - bstrie:hashfrom, r=joshtriplett
Stabilize `impl From<[(K, V); N]> for HashMap` (and friends)
In addition to allowing HashMap to participate in Into/From conversion, this adds the long-requested ability to use constructor-like syntax for initializing a HashMap:
```rust
let map = HashMap::from([
(1, 2),
(3, 4),
(5, 6)
]);
```
This addition is highly motivated by existing precedence, e.g. it is already possible to similarly construct a Vec from a fixed-size array:
```rust
let vec = Vec::from([1, 2, 3]);
```
...and it is already possible to collect a Vec of tuples into a HashMap (and vice-versa):
```rust
let vec = Vec::from([(1, 2)]);
let map: HashMap<_, _> = vec.into_iter().collect();
let vec: Vec<(_, _)> = map.into_iter().collect();
```
...and of course it is likewise possible to collect a fixed-size array of tuples into a HashMap ([but not vice-versa just yet](https://github.com/rust-lang/rust/issues/81615)):
```rust
let arr = [(1, 2)];
let map: HashMap<_, _> = std::array::IntoIter::new(arr).collect();
```
Therefore this addition seems like a no-brainer.
fn main() {}
```
This PR makes this code no longer ICE, it was ICE'ing previously because when building substs for `Bar<N1>` we would subst the anon ct: `ConstKind::Unevaluated({N + 1}, substs: [N, M])` with substs of `[N1]`. the anon const has forward declared params supplied though so we end up trying to substitute the provided `M` param which causes the ICE.
This PR doesn't handle the predicates of the const so
```rust
trait Foo<const N: usize> { const Assoc: usize; }
pub struct Bar<const N: usize = { <()>::Assoc }> where (): Foo<N>;
```
Resolves to `<() as Foo<N>>::Assoc` which can allow for using fwd declared params indirectly.
```rust
trait Foo<const N: usize> {}
struct Bar<const N: usize = { 2 + 3 }> where (): Foo<N>;
```
This code also ICEs under this PR because instantiating the default's predicates causes an ICE as predicates_of contains predicates with fwd declared params
PR was briefly discussed [in this zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/260443-project-const-generics/topic/evil.20preds.20in.20param.20env.20.2386580)
Auto merge of #87434 - Manishearth:rollup-b09njin, r=Manishearth
Rollup of 9 pull requests
Successful merges:
- #87348 (Fix span when suggesting to add an associated type bound)
- #87359 (Remove detection of rustup and cargo in 'missing extern crate' diagnostics)
- #87370 (Add support for powerpc-unknown-freebsd)
- #87389 (Rename `known_attrs` to `expanded_inert_attrs` and move to rustc_expand)
- #87395 (Clear up std::env::set_var panic section.)
- #87403 (Implement `AssignToDroppingUnionField` in THIR unsafeck)
- #87410 (Mark `format_args_nl` as `#[doc(hidden)]`)
- #87419 (IEEE 754 is not an RFC)
- #87422 (DOC: remove unnecessary feature crate attribute from example code)
- A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)
For all Rust targets on FreeBSD, it's rust@FreeBSD.org.
- Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
Done.
- Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
Done
- Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
Done.
- The target must not introduce license incompatibilities.
Done.
- Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Fine with me.
- The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
Done.
- If the target supports building host tools (such as rustc or cargo), those host tools must not depend on proprietary (non-FOSS) libraries, other than ordinary runtime libraries supplied by the platform and commonly used by other binaries built for the target. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
Done.
- Targets should not require proprietary (non-FOSS) components to link a functional binary or library.
Done.
- "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.
Fine with me.
- Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
Ok.
- This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements.
Ok.
- Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.
std is implemented.
- The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running tests (even if they do not pass), the documentation must explain how to run tests for the target, using emulation if possible or dedicated hardware if necessary.
Hm, building is possible the same way as other Rust on FreeBSD targets.
- Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via `@)` to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.
Ok.
- Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
Ok.
- Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
Ok.
- In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.
Ok.
Rollup merge of #87359 - jyn514:bless-rustup, r=estebank
Remove detection of rustup and cargo in 'missing extern crate' diagnostics
Previously, this would change the test output when RUSTUP_HOME was set:
```
---- [ui] ui/issues/issue-49851/compiler-builtins-error.rs stdout ----
diff of stderr:
1 error[E0463]: can't find crate for `core`
2 |
3 = note: the `thumbv7em-none-eabihf` target may not be installed
+ = help: consider downloading the target with `rustup target add thumbv7em-none-eabihf`
4
5 error: aborting due to previous error
6
```
Originally, I fixed it by explicitly unsetting RUSTUP_HOME in
compiletest. Then I realized that almost no one has RUSTUP_HOME set,
since rustup doesn't set it itself. It does set RUST_RECURSION_COUNT
whenever it launches a proxy, though - use that instead.
r? ```@estebank``` cc ```@petrochenkov``` ```@kinnison```
Rollup merge of #87348 - SkiFire13:fix-87261, r=oli-obk
Fix span when suggesting to add an associated type bound
Fixes #87261
Note that this fix is not perfect, it ~~will still give incorrect~~ won't give suggestions in some situations:
- If the associated type is defined on a supertrait of those contained in the opaque type, it will fallback to the previous behaviour, e.g. if `AssocTy` is defined on the trait `Foo`, `Bar` has `Foo` as supertrait and the opaque type is a `impl Bar + Baz`.
- If the the associated type is defined on a generic trait and the opaque type includes two versions of that generic trait, e.g. the opaque type is `impl Foo<A> + Foo<B>`