Use poison instead of undef
In cases where it is legal, we should prefer poison values over undef values.
This replaces undef with poison for aggregate construction and for uninhabited types. There are more places where we can likely use poison, but I wanted to stay conservative to start with.
In particular the aggregate case is important for newer LLVM versions, which are not able to handle an undef base value during early optimization due to poison-propagation concerns.
r? `@cuviper`
Shrink unicode case-mapping LUTs by 24k
I was looking into the binary bloat of a small program using `str::to_lowercase` and `str::to_uppercase`, and noticed that the lookup tables used for case mapping had a lot of zero-bytes in them. The reason for this is that since some characters map to up to three other characters when lower or uppercased, the LUTs store a `[char; 3]` for each character. However, the vast majority of cases only map to a single new character, in other words most of the entries are e.g. `(lowerc, [upperc, '\0', '\0'])`.
This PR introduces a new encoding scheme for these tables.
The changes reduces the size of my test binary by about 24K.
I've also done some `#[bench]`marks on unicode-heavy test data, and found that the performance of both `str::to_lowercase` and `str::to_uppercase` improves by up to 20%. These measurements are obviously very dependent on the character distribution of the data.
Someone else will have to decide whether this more complex scheme is worth it or not, I was just goofing around a bit and here's what came out of it 🤷♂️ No hard feelings if this isn't wanted!
Make helper functions private in fn_ctxt/adjust_fulfillment_errors
Two helper functions in `rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs` were previously made `pub` impl members, because they were also used in `rustc_hir_typeck/src/fn_ctxt/check.rs` (see #107746).
However, that's no longer the case, so the FIXME suggesting they be made private can now be implemented.
Implement non-const `Destruct` trait in new solver
Makes it so that we can call stdlib methods like `Option::map` in **non-const** environments, since *many* stdlib methods have `Destruct` bounds 😅
This doesn't bother to implement `const Destruct` yet, but it shouldn't be too hard to do so. Just didn't bother since we already don't have much support for const traits in the new solver anyways. I'd be happy to add skeleton support for `const Destruct`, though, if the reviewer desires.
Rollup of 9 pull requests
Successful merges:
- #108629 (rustdoc: add support for type filters in arguments and generics)
- #108924 (panic_immediate_abort requires abort as a panic strategy)
- #108961 (Refine error spans for const args in hir typeck)
- #108986 (sync LVI tests)
- #109142 (Add block-based mutex unlocking example)
- #109368 (fix typo in the creation of OpenOption for RustyHermit)
- #109493 (Return nested obligations from canonical response var unification)
- #109515 (Add AixLinker to support linking on AIX)
- #109536 (resolve: Rename some cstore methods to match queries and add comments)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
resolve: Rename some cstore methods to match queries and add comments
about costs associated with replacing them with query calls.
Supersedes https://github.com/rust-lang/rust/pull/108346.
r? `@cjgillot`
Return nested obligations from canonical response var unification
Handle alias-eq obligations being emitted from `instantiate_and_apply_query_response` in:
* `EvalCtxt` - by processing the nested obligations in the next loop by `new_goals`
* `FulfillCtxt` - by adding the nested obligations to the fulfillment's pending obligations
* `InferCtxt::evaluate_obligation` - ~~by returning `EvaluationResult::EvaluatedToAmbig` (boo 👎, see the FIXME)~~ same behavior as above, since we use fulfillment and `select_where_possible`
The only one that's truly sketchy is `evaluate_obligation`, but it's not hard to modify this behavior moving forward.
From #109037, I think a smaller repro could be crafted if I were smarter, but I am not, so I just took this from #105878.
r? `@lcnr` cc `@BoxyUwU`
fix typo in the creation of OpenOption for RustyHermit
Due to this typo we have to build a workaround for issue hermitcore/libhermit-rs#191.
RustyHermit is a tier 3 platform and backward compatibility does not have to be guaranteed.
Add block-based mutex unlocking example
This modifies the existing example in the Mutex docs to show both `drop()` and block based early unlocking.
Alternative to #81872, which is getting closed.
sync LVI tests
The LVI tests for the `x86_64-fortanix-unknown-sgx` target have gotten out of sync. LVI is still mitigated correctly, but the LVI tests need minor modifications. Other (non LVI-related) tests fail when the target applies LVI mitigations as they assume the generated code contains forbidden instructions such as `retq`. These tests are ignored for the sgx environment.
cc: `@jethrogb`
Refine error spans for const args in hir typeck
Improve just a couple of error messages having to do with mismatched consts.
r? `@ghost` i'll put this up when the dependent commits are merged
panic_immediate_abort requires abort as a panic strategy
Guide `panic_immediate_abort` users away from `-Cpanic=unwind` and towards `-Cpanic=abort` to avoid an accidental use of the feature with the unwind strategy, e.g., on a targets where unwind is the default.
The `-Cpanic=unwind` combination doesn't offer the same benefits, since the code would still be generated under the assumption that functions implemented in Rust can unwind.
rustdoc: add support for type filters in arguments and generics
This makes sense, since the search index has the information in it, and it's more useful for function signature searches since a function signature search's item type is, by definition, some type of function (there's more than one, but not very many).
New lint: detect unnecessary struct building
Fixes#10476.
Running this lint on the top 500 crates produced one hit (in `rust-lang/rust-bindgen`) and [a PR has been submitted there](https://github.com/rust-lang/rust-bindgen/pull/2440).
changelog: [`unnecessary_struct_initialization`]: new lint
Move useless_anynous_reexport lint into unused_imports
As mentioned in https://github.com/rust-lang/rust/pull/109003, this check should have been merged with `unused_imports` in the start.
r? `@petrochenkov`
Add `try_canonicalize` to `rustc_fs_util` and use it over `fs::canonicalize`
This adds `try_canonicalize` which tries to call `fs::canonicalize`, but falls back to `std::path::absolute` if it fails. Existing `canonicalize` calls are replaced with it. `fs::canonicalize` is not guaranteed to work on Windows.
Fix the ffi_unwind_calls lint documentation
This fixes the [`ffi_unwind_calls`](https://doc.rust-lang.org/nightly/rustc/lints/listing/allowed-by-default.html#ffi-unwind-calls) documentation to show its output correctly. Currently it is showing the text `{{produces}}` which is not how it should look.
This fixes it by not ignoring the example. I'm not sure why it was ignored, as the way the lint currently works it doesn't seem to require external linkage. This also fixes several mistakes in the example:
* There is no `ffi_unwind_calls` feature.
* Denies the lint (which is otherwise allow be default).
* Removes the `mod impl` which is not valid Rust syntax, and doesn't appear to be needed anyways.
The output now looks like:
```
warning: call to foreign function with FFI-unwind ABI
--> lint_example.rs:10:14
|
10 | unsafe { foo(); }
| ^^^^^ call to foreign function with FFI-unwind ABI
|
note: the lint level is defined here
--> lint_example.rs:2:9
|
2 | #![warn(ffi_unwind_calls)]
| ^^^^^^^^^^^^^^^^
warning: call to function pointer with FFI-unwind ABI
--> lint_example.rs:12:14
|
12 | unsafe { ptr(); }
| ^^^^^ call to function pointer with FFI-unwind ABI
```
This also includes some updates to the lint-docs tool to help with this issue:
* Adds a check if a lint documentation has `{{produces}}` with an ignored example, and generates an error.
* All instances of a lint are now displayed. Previously it only showed the first time the lint fires. Some examples may trigger a lint multiple times, and they are all now displayed.
Lint ambiguous glob re-exports
Attempts to fix#107563.
We currently already emit errors for ambiguous re-exports when two names are re-exported *specifically*, i.e. not from glob exports. This PR attempts to emit deny-by-default lints for ambiguous glob re-exports.
Add `-Z time-passes-format` to allow specifying a JSON output for `-Z time-passes`
This adds back the `-Z time` option as that is useful for [my rustc benchmark tool](https://github.com/Zoxc/rcb), reverting https://github.com/rust-lang/rust/pull/102725. It now uses nanoseconds and bytes as the units so it is renamed to `time-precise`.
Clarify `Error::last_os_error` can be weird
Fundamentally, querying the OS for error codes is a process that is deeply subject to the whims of chance and fortune. We can account for OS, but not for every combination of platform APIs. A compiled binary may not recognize new errors introduced years later. We should clarify a few especially odd situations, and what they mean: We can effectively promise nothing... if you ask for Rust to decode errors where none have occurred.
This allows removing mention of ErrorKind::Uncategorized.
That error variant is hidden deliberately, so we should not explicitly mention it.
This fixes#106937.
Since you had an opinion also: Does this solution seem acceptable?
r? ``@ChrisDenton``
