Perform unused assignment and unused variables lints on MIR.
Rebase of https://github.com/rust-lang/rust/pull/101500
Fixes https://github.com/rust-lang/rust/issues/51003.
The first commit moves detection of uninhabited types from the current liveness pass to MIR building.
In order to keep the same level of diagnostics, I had to instrument MIR a little more:
- keep for which original local a guard local is created;
- store in the `VarBindingForm` the list of introducer places and whether this was a shorthand pattern.
I am not very proud of the handling of self-assignments. The proposed scheme is in two parts: first detect probable self-assignments, by pattern matching on MIR, and second treat them specially during dataflow analysis. I welcome ideas.
Please review carefully the changes in tests. There are many small changes to behaviour, and I'm not sure all of them are desirable.
core: simplify `Extend` for tuples
This is an alternative to https://github.com/rust-lang/rust/pull/137400. The current macro is incredibly complicated and introduces subtle bugs like calling the `extend_one` of the individual collections in backwards order. This PR drastically simplifies the macro by removing recursion and moving the specialization out of the macro. It also fixes the ordering issue described above (I've stolen the test of the new behaviour from https://github.com/rust-lang/rust/pull/137400). Additionally, the 1-tuple is now special-cased to allow taking advantage of the well-optimized `Extend` implementations of the individual collection.
Validate CopyForDeref and DerefTemps better and remove them from runtime MIR
(split from my WIP rust-lang/rust#145344)
This PR:
- Removes `Rvalue::CopyForDeref` and `LocalInfo::DerefTemp` from runtime MIR
- Using a new mir pass `EraseDerefTemps`
- `CopyForDeref(x)` is turned into `Use(Copy(x))`
- `DerefTemp` is turned into `Boring`
- Not sure if this part is actually necessary, it made more sense in rust-lang/rust#145344 with `DerefTemp` storing actual data that I wanted to keep from having to be kept in sync with the rest of the body in runtime MIR
- Checks in validation that `CopyForDeref` and `DerefTemp` are only used together
- Removes special handling for `CopyForDeref` from many places
- Removes `CopyForDeref` from `custom_mir` reverting rust-lang/rust#111587
- In runtime MIR simple copies can be used instead
- In post cleanup analysis MIR it was already wrong to use due to the lack of support for creating `DerefTemp` locals
- Possibly this should be its own PR?
- Adds an argument to `deref_finder` to avoid creating new `DerefTemp`s and `CopyForDeref` in runtime MIR.
- Ideally we would just avoid making intermediate derefs instead of fixing it at the end of a pass / during shim building
- Removes some usages of `deref_finder` that I found out don't actually do anything
r? oli-obk
Move more code to `RawVec::finish_grow`
This move a branch and more code into the cold method `finish_grow`, which means that less code is inlined at each `try_reserve` site. Additionally, this reduces the amount of parameters, so they can all be passed by registers.
remove `#[rustc_inherit_overflow_checks]` from `is_multiple_of`
Most likely this was just a result of copy-pasting. The attribute has no effect, because `%` always uses overflow checks.
r? `@Amanieu`
cc `@RalfJung`
Remove StatementKind::Deinit.
It is a remnant from the time we deaggreated MIR.
Now, it is only constructed by the `LargeEnums` MIR pass, which is disabled by default.
Prefer to use repeat_n over repeat().take()
More from https://github.com/rust-lang/rust/pull/147464, but batch processed with `ast-grep` to find and replace.
second commit add notes for library: affaf532f9
r? ``@RalfJung``
Clarify how to remediate the panic_immediate_abort error
Users who build `core` for the sole purpose of enabling `panic_immediate_abort` might expect "`panic_immediate_abort` is now a real panic strategy" to mean that setting `panic = "immediate-abort"` in `Cargo.toml` or `-Cpanic=immediate-abort` in `RUSTFLAGS` to be sufficient for migration. But this is not the case, `core` still needs to be built for those changes to take effect.
See https://github.com/rust-lang/rust/issues/146974 for additional context.
See https://github.com/rust-lang/rust/issues/147286 and https://github.com/rust-lang/cargo/issues/16042 for the revelant tracking issues.
give a better example why `std` modules named like primitives are needed
A small update to the `std` `lib.rs` introduction to replace mentions of `std::i32` (never needed) with `std::char` (sometimes needed).
Related to rust-lang/rust#146882.
some more `proc_macro` cleanups
Several smaller cleanups to `proc_macro`. Commits 1 and 3 seem pretty trivial to me, commit 2 might be worth it or not.
Followup to rust-lang/rust#147166.
Users who build `core` for the sole purpose of enabling `panic_immediate_abort` might expect
"`panic_immediate_abort` is now a real panic strategy" to mean that setting `panic =
"immediate-abort"` in `Cargo.toml` or `-Cpanic=immediate-abort` in `RUSTFLAGS` to be sufficient for
migration. But this is not the case, `core` still needs to be built for those changes to take
effect.
See https://github.com/rust-lang/rust/issues/146974 for additional context.
Rollup of 8 pull requests
Successful merges:
- rust-lang/rust#146865 (kcfi: only reify trait methods when dyn-compatible)
- rust-lang/rust#147205 (Add a new `wasm32-wasip3` target to Rust)
- rust-lang/rust#147322 (cg_llvm: Consistently import `llvm::Type` and `llvm::Value`)
- rust-lang/rust#147398 (Fix; correct placement of type inference error for method calls)
- rust-lang/rust#147410 (Update `S-waiting-on-team` refs to new `S-waiting-on-{team}` labels)
- rust-lang/rust#147422 (collect-license-metadata: Print a diff of the expected output)
- rust-lang/rust#147431 (compiletest: Read the whole test file before parsing directives)
- rust-lang/rust#147433 (Fix doc comment)
Failed merges:
- rust-lang/rust#147390 (Use globals instead of metadata for std::autodiff)
r? `@ghost`
`@rustbot` modify labels: rollup
Add a new `wasm32-wasip3` target to Rust
This commit adds a new tier 3 target to rustc, `wasm32-wasip3`. This follows in the footsteps of the previous `wasm32-wasip2` target and is used to represent binding to the WASIp3 set of APIs managed by the WASI subgroup to the WebAssembly Community Group.
As of now the WASIp3 set of APIs are not finalized nor standardized. They're in the process of doing so and the current trajectory is to have the APIs published in December of this year. The goal here is to get the wheels turning in Rust to have the target in a
more-ready-than-nonexistent state by the time this happens in December.
For now the `wasm32-wasip3` target looks exactly the same as `wasm32-wasip2` except that `target_env = "p3"` is specified. This indicates to crates in the ecosystem that WASIp3 APIs should be used, such as the [`wasip3` crate]. Over time this target will evolve as implementation in guest toolchains progress, notably:
* The standard library will use WASIp3 APIs natively once they're finalized in the WASI subgroup.
* Support through `wasi-libc` will be updated to use WASIp3 natively which Rust will then transitively use.
* Longer-term, features such as cooperative multithreading will be added to the WASIp3-track of targets to enable using `std::thread`, for example, on this target.
These changes are all expected to be non-breaking changes for users of this target. Runtimes supporting WASIp3, currently Wasmtime and Jco, support WASIp2 APIs as well and will work with components whether or not they import WASIp2, both WASIp2 and WASIp3, or just WASIp3 APIs. This means that changing the internal implementation details of libstd over time is expected to be a non-breaking change.
[`wasip3` crate]: https://crates.io/crates/wasip3
Rollup of 7 pull requests
Successful merges:
- rust-lang/rust#145943 (stdlib docs: document lifetime extension for `format_args!`'s arguments)
- rust-lang/rust#147243 (cmse: disallow `impl Trait` in `cmse-nonsecure-entry` return types)
- rust-lang/rust#147402 ([rustdoc] Don't serialize & deserialize data that doesn't go OTW)
- rust-lang/rust#147418 (Fix target list of `link_section`)
- rust-lang/rust#147429 (Print tip for human error format in runtest)
- rust-lang/rust#147441 (Fix comments error for Provenance impls)
- rust-lang/rust#147442 (c-variadic: fix thir-print for `...` without a pattern)
r? `@ghost`
`@rustbot` modify labels: rollup
stdlib docs: document lifetime extension for `format_args!`'s arguments
Since rust-lang/rust#140748 is stable and rust-lang/rust#92698 is closed, the section about `format_args!`'s argument lifetime limitation is outdated. I've updated it to point to the Reference docs, which will specify lifetime extension rules for builtin macros once rust-lang/reference#1980 or equivalent is merged.
I've also taken the liberty of updating one of the doctests to assign the result of `format_args!` to a variable, both to provide an example and because I think it reads a little better.
r? `@m-ou-se`
Improve the advice given by panic_immediate_abort
Now that https://github.com/rust-lang/rust/pull/147338 is merged, users should consider using the Cargo support for immediate-aborting panics.
Make `fmt::Write` a diagnostic item
I'm working on an enhancement to [`clippy::format_push_string`](https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string), which would suggest an autofix to replace `push_str`/`+=` with `write!`. But that could require importing `std::fmt::Write`, and so I need this diagnostic item to check if it's already in scope.
The reason I called it `FmtWrite` and not just `Write` is that there's already an `IoWrite` defined.
std: `sys::net` cleanups
This PR contains three improvements to the socket-based networking implementation (aa1263e768 is just to add the now missing `unsafe`). Best reviewed commit-by-commit.
