stricter hidden type wf-check [based on #115008]
Original work by `@aliemjay` in #115008. A huge thanks to them for originally figuring out this approach ❤️
Fixes https://github.com/rust-lang/rust/issues/114728
Fixes https://github.com/rust-lang/rust/issues/114572
Instead of adding the `WellFormed` obligations when relating opaque types, we now always emit such an obligation when defining the hidden type.
This causes nested opaque types which aren't wf to error, see the comment below for the described impact. I believe this change to be desirable as it significantly reduces complexity by removing special-cases.
It also caused an issue with RPITIT: in defaulted trait methods, we add a `Projection(synthetic_assoc, rpit_of_trait_method)` clause to the `param_env`. This clause is not added to the `ParamEnv` of the nested coroutines. This caused a normalization failure in `fn check_coroutine_obligations` with the new solver. I fixed that by using the env of the typeck root instead.
r? `@oli-obk`
Embed length of offset/position into Span tag byte
This cuts the average bytes/relative span from 3.5 to 3.2 on libcore, ultimately saving ~400kb of data.
Rollup of 9 pull requests
Successful merges:
- #121065 (Add basic i18n guidance for `Display`)
- #121744 (Stop using Bubble in coherence and instead emulate it with an intercrate check)
- #121829 (Dummy tweaks (attempt 2))
- #121857 (Implement async closure signature deduction)
- #121894 (const_eval_select: make it safe but be careful with what we expose on stable for now)
- #122014 (Change some attributes to only_local.)
- #122016 (will_wake tests fail on Miri and that is expected)
- #122018 (only set noalias on Box with the global allocator)
- #122028 (Remove some dead code)
r? `@ghost`
`@rustbot` modify labels: rollup
Rollup of 8 pull requests
Successful merges:
- #121202 (Limit the number of names and values in check-cfg diagnostics)
- #121301 (errors: share `SilentEmitter` between rustc and rustfmt)
- #121658 (Hint user to update nightly on ICEs produced from outdated nightly)
- #121846 (only compare ambiguity item that have hard error)
- #121961 (add test for #78894#71450)
- #121975 (hir_analysis: enums return `None` in `find_field`)
- #121978 (Fix duplicated path in the "not found dylib" error)
- #121991 (Merge impl_trait_in_assoc_types_defined_by query back into `opaque_types_defined_by`)
r? `@ghost`
`@rustbot` modify labels: rollup
only set noalias on Box with the global allocator
As discovered in https://github.com/rust-lang/miri/issues/3341, `noalias` and custom allocators don't go well together.
rustc can now check whether a Box uses the global allocator. This replaces the previous ad-hoc and rather unprincipled check for a zero-sized allocator.
This is the rustc part of fixing that; Miri will also need a patch.
const_eval_select: make it safe but be careful with what we expose on stable for now
As this is all still nightly-only I think `````@rust-lang/wg-const-eval````` can do that without involving t-lang.
r? `````@oli-obk`````
Cc `````@Nilstrieb````` -- the updated version of your RFC would basically say that we can remove these comments about not making behavior differences visible in stable `const fn`
Implement async closure signature deduction
Self-explanatory from title.
Regarding the interaction between signature deduction, fulfillment, and the new trait solver: I'm not worried about implementing closure signature deduction here because:
1. async closures are unstable, and
2. I'm reasonably confident we'll need to support signature deduction in the new solver somehow (i.e. via proof trees, which seem very promising).
This is in contrast to #109338, which was closed because it generalizes signature deduction for a *stable* kind of expression (`async {}` blocks and `Future` traits), and which proliferated usage may pose a stabilization hazard for the new solver.
I'll be certain to make sure sure we revisit the closure signature deduction problem by the time that async closures are being stabilized (which isn't particularly soon) (edit: Put it into the async closure tracking issue). cc `````@lcnr`````
r? `````@oli-obk`````
Stop using Bubble in coherence and instead emulate it with an intercrate check
r? `````@compiler-errors`````
This change is kinda funny, because all I've done is reimplement `Bubble` behaviour for coherence without using `Bubble` explicitly.
Add basic i18n guidance for `Display`
I've tried to be relatively noncommittal here. The part I think is most important is to mention the concept of "display adapters" *somewhere* in the `std::fmt` documentation that has some chance of being discovered when people go looking for ways to provide context when `Display`ing their type.
Rendered:
> ### Internationalization
>
> Because a type can only have one `Display` implementation, it is often preferable to only implement `Display` when there is a single most "obvious" way that values can be formatted as text. This could mean formatting according to the "invariant" culture and "undefined" locale, or it could mean that the type display is designed for a specific culture/locale, such as developer logs.
>
> If not all values have a justifiably canonical textual format or if you want to support alternative formats not covered by the standard set of possible [formatting traits], the most flexible approach is display adapters: methods like [`str::escape_default`] or [`Path::display`] which create a wrapper implementing `Display` to output the specific display format.
>
> [formatting traits]: https://doc.rust-lang.org/nightly/std/fmt/index.html#formatting-traits
> [`str::escape_default`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.escape_default
> [`Path::display`]: https://doc.rust-lang.org/nightly/std/path/struct.Path.html#method.display
The module docs do already have a [localization header](https://doc.rust-lang.org/nightly/std/fmt/index.html#localization), so maybe this header should be l10n instead of i18n, or maybe this information should live under that header? I'm not sure, but here on the `Display` trait at least isn't a *bad* spot to put it.
The other side of this that comes up a lot is `FromStr` compatibility, but that's for a different PR.
Merge impl_trait_in_assoc_types_defined_by query back into `opaque_types_defined_by`
Instead, when we're collecting opaques for associated items, we choose the right collection mode depending on whether we're collecting for an associated item of a trait impl or not.
r? ```@compiler-errors```
follow up to https://github.com/rust-lang/rust/pull/121838
Fix duplicated path in the "not found dylib" error
While working on the gcc backend, I couldn't figure out why I had this error:
```
error: couldn't load codegen backend /checkout/compiler/rustc_codegen_gcc/target/release/librustc_codegen_gcc.so/checkout/compiler/rustc_codegen_gcc/target/release/librustc_codegen_gcc.so: cannot open shared object file: No such file or directory
```
As you can see, the path is duplicated for some reason. After investigating a bit more, I realized that `libloading::Error::LoadLibraryExW` starts with the path of the not found dylib, making it appear twice in our error afterward (because we do render it like this: `{path}{err}`, and since the `err` starts with the path...).
Thanks to `````@bjorn3````` for linking me to https://github.com/rust-lang/rust/pull/121392. :)
hir_analysis: enums return `None` in `find_field`
Fixes#121757.
Unnamed union fields with enums are checked for, but if `find_field` causes an ICE then the compiler won't get to that point.
Hint user to update nightly on ICEs produced from outdated nightly
This is a conservative best-effort approach to detect a potentially outdated nightly; it will fallback to the regular ICE-reporting if any of the following cases are true:
- Channel is not nightly
- Version information is not available
- Version date is not parseable as a YYYY-MM-DD or is missing
- System time is at least 36 hours ahead of the user's nightly release datetime.
- Any internal features are used.
Note that I'm not sure how to make a test for this: I tested this manually by `CFG_VER_DATE="2020-02-02" ./x build library --stage 1`, and also changing the channel detection in `rustc_driver_impl` from `Some("nightly")` to `Some("nightly" | "dev")`, and then running `rustc +stage1 test.rs -Ztreat-err-as-bug=1` with a non-existent `test.rs`.
<img width="1145" alt="Screenshot 2024-02-27 at 01 12 28" src="https://github.com/rust-lang/rust/assets/39484203/eff6af2e-4b19-4a70-af57-cd739ecf0e84">
Closes#118832.
errors: share `SilentEmitter` between rustc and rustfmt
Fixesrust-lang/rustfmt#6082.
Shares the `SilentEmitter` between rustc and rustfmt, and gives it a fallback bundle (since it can emit diagnostics in some contexts).
Limit the number of names and values in check-cfg diagnostics
The Rust for Linux [feedback](https://github.com/rust-lang/rust/issues/82450#issuecomment-1947462977) to the check-cfg Call for Testing, revealed a weakness in the check-cfg. They are unbounded and in the case RfL they have ~20k cfgs and having them printed (even once) is unbearable.
This PR limits it to 35 (28 rustc well known + `feature` + `docsrs` + 5 custom) which feels like a good middle ground for regular users (i.e. Cargo users).
When it goes over that limit print the N first with " and X more".
``@rustbot`` label +F-check-cfg
Add a `description` field to target definitions
Starts addressing https://github.com/rust-lang/rust/pull/121051#pullrequestreview-1890562844
This is the short description (`64-bit MinGW (Windows 7+)`) including the platform requirements.
The reason for doing it like this is that this PR will be quite prone to conflicts whenever targets get added, so it should be as simple as possible to get it merged. Future PRs which migrate targets are scoped to groups of targets, so they will not conflict as they can just touch these.
This moves some of the information from the rustc book into the compiler.
It cannot be queried yet, that is future work. It is also future work to fill out all the descriptions, which will coincide with the work of moving over existing target docs to the new format.
r? `@davidtwco` but anyone is also free to steal it
Instead, when we're collecting opaques for associated items, we choose the right collection mode depending on whether we're collecting for an associated item of a trait impl or not.
This is the short description (`64-bit MinGW (Windows 7+)`) including
the platform requirements.
The reason for doing it like this is that this PR will be quite prone to
conflicts whenever targets get added, so it should be as simple as
possible to get it merged. Future PRs which migrate targets are scoped
to groups of targets, so they will not conflict as they can just touch
these.
This moves some of the information from the rustc book into the
compiler.
It cannot be queried yet, that is future work. It is also future work to
fill out all the descriptions, which will coincide with the work of
moving over existing target docs to the new format.
net: Don't use checked arithmetic when parsing numbers with known max digits
Add a branch to `Parser::read_number` that determines whether checked or regular arithmetic is used.
- If `max_digits.is_some()`, then we know we are parsing a `u8` or `u16` because `read_number` is only called with `Some(3)` or `Some(4)`. Both types fit within a `u32` without risk of overflow. Thus, we can use plain arithmetic to avoid extra instructions from `checked_mul` and `checked_add`.
Add benches for `IpAddr`, `Ipv4Addr`, `Ipv6Addr`, `SocketAddr`, `SocketAddrV4`, and `SocketAddrV6` parsing
tidy: split dots in filename not the entire path when checking for stray stdout/stderr files
I committed a path crime by splitting the entire path on `.`, when I meant to split on the filename. This means that any parent folders which contain `.` will cause tidy failure. Added a regression test so that doesn't happen again.
### Follow-up
- [ ] Adjust rustc-dev-guide to document assert on test name not containing dots. https://github.com/rust-lang/rustc-dev-guide/pull/1927Fixes#121986.
Add ASCII fast-path for `char::is_grapheme_extended`
I discovered that `impl Debug for str` is quite slow because it ends up doing a `unicode_data::grapheme_extend::lookup` for each char, which ends up doing a binary search.
This introduces a fast-path for ASCII chars which do not have this property.
The `lookup` is thus completely gone from profiles.
---
As a followup, maybe it’s worth implementing this fast path directly in `unicode_data` so that it can check for the lower bound directly before going to a potentially expensive binary search.
Rollup of 10 pull requests
Successful merges:
- #121213 (Add an example to demonstrate how Rc::into_inner works)
- #121262 (Add vector time complexity)
- #121287 (Clarify/add `must_use` message for Rc/Arc/Weak::into_raw.)
- #121664 (Adjust error `yield`/`await` lowering)
- #121826 (Use root obligation on E0277 for some cases)
- #121838 (Use the correct logic for nested impl trait in assoc types)
- #121913 (Don't panic when waiting on poisoned queries)
- #121987 (pattern analysis: abort on arity mismatch)
- #121993 (Avoid using unnecessary queries when printing the query stack in panics)
- #121997 (interpret/cast: make more matches on FloatTy properly exhaustive)
r? `@ghost`
`@rustbot` modify labels: rollup
interpret/cast: make more matches on FloatTy properly exhaustive
Actually implementing these is pretty trivial (at least once all the scalar methods are added, which happens in https://github.com/rust-lang/rust/pull/121926), but I'm staying consistent with the other f16/f128 PRs. Also adding adding all the tests to Miri would be quite a lot of work.
There's probably some way to reduce the code duplication here with more use of generics... but that's a future refactor.^^
r? ```@tgross35```
pattern analysis: abort on arity mismatch
This is one more PR replacing panics by `Err()` aborts. I recently audited all the `unwrap()` calls, but I had forgotten about array accesses. (Again [discovered by rust-analyzer](https://github.com/rust-lang/rust-analyzer/issues/16746)).
r? ```@compiler-errors```
Use the correct logic for nested impl trait in assoc types
Previously we accidentally continued with the TAIT visitor, which allowed more than we wanted to.
r? ```@compiler-errors```
