Cleanup attributes around unchecked shifts and unchecked negation in const
The underlying intrinsic is marked as "safe to expose on stable", so we shouldn't need any `rustc_allow_const_fn_unstable(unchecked_shifts)` anywhere. However, bootstrap rustc doesn't yet have the new const stability checks, so these changes only apply under `cfg(not(bootstrap))`.
rustdoc: Directly use rustc_abi instead of reexports
rustc_target reexports a lot of things that are in rustc_abi, but that will be over soon and now is probably a good time to switch. Uses of rustc_target remain where they inquire about the target tuple.
Add `f16` and `f128` to `invalid_nan_comparison`
Currently `f32_nan` and `f64_nan` are used to provide the `invalid_nan_comparison` lint. Since we have `f16_nan` and `f128_nan`, hook these up so the new float types get the same lints.
Implement suggestion for never type fallback lints
r? ```@WaffleLapkin```
Just opening this up for vibes; it's not done yet. I'd still like to make this suggestable in a few more cases before merge:
- [x] Try to annotate `_` -> `()`
- [x] Try to annotate local variables if they're un-annotated: `let x = ...` -> `let x: () = ...`
- [x] Try to annotate the self type of a `Trait::method()` -> `<() as Trait>::method()`.
The only other case we may want to suggest is a missing turbofish, like `f()` -> `f::<()>()`. That may be possible, but seems overly annoying.
This partly addresses https://github.com/rust-lang/rust/issues/132358; the other half of fixing that would be to make the error message a bit better, perhaps just special casing the `?` operator 🤔 I don't think I'll do that part.
Remove support for `-Zprofile` (gcov-style coverage instrumentation)
Tracking issue: #42524
MCP: https://github.com/rust-lang/compiler-team/issues/798
---
This PR removes the unstable `-Zprofile` flag, which enables ”gcov-style” coverage instrumentation, along with its associated `-Zprofile-emit` configuration flag.
(The profile flag predates and is almost entirely separate from the stable `-Cinstrument-coverage` flag.)
Notably, the `-Zprofile` flag:
- Is largely untested in-tree, having only one run-make test that does not check whether its output is correct or useful.
- Has no known maintainer.
- Has seen no push towards stabilization.
- Has at least one severe regression reported in 2022 that apparently remains unaddressed.
- #100125
- Is confusingly named, since it appears to be more about coverage than performance profiling, and has nothing to do with PGO.
- Is fundamentally limited by relying on counters auto-inserted by LLVM, with no knowledge of Rust beyond debuginfo.
Double-check conditional constness in MIR
To prevent any unchecked `~const` bounds from leaking through during MIR lowering.
If this check fails, it will eventually just delay a bug, but for now it reports errors. That error reporting may be redundant if we're calling it from code that already doesn't allow `~const` (i.e. when the `effects` and `const_trait_impl` gates are disabled), but I don't think it's that big of a deal.
edit: This also makes sure that we issue a const stability error if we encounter *any* function with const conditions when `const_trait_impl` is not enabled. This ensures that that feature remains airtight.
rustc_target reexports a lot of things that are in rustc_abi, but
that will be over soon and now is probably a good time to switch.
Uses of rustc_target remain where they inquire about the target tuple.
The OS version depends on the deployment target environment variables,
the access of which we want to move to later in the compilation pipeline
that has access to more information, for example `env_depinfo`.
The OS version depends on the deployment target environment variables,
the access of which we want to move to later in the compilation pipeline
that has access to more information, for example `env_depinfo`.
Some where clause lowering simplifications
Rename `PredicateFilter::SelfThatDefines` to `PredicateFilter::SelfTraitThatDefines` to make it clear that it's only concerned with converting *traits*, and make it do a bit less work when converting bounds.
Also, make the predicate filter matching in `probe_ty_param_bounds_in_generics` explicit, and simply the args it receives a bit.
This is an API that naturally should exist as a combination of byte_offset_from and sub_ptr
both existing (they showed up at similar times so this union was never made). Adding these
is a logical (and perhaps final) precondition of stabilizing ptr_sub_ptr (#95892).
Explain why clippy's HIR const eval exists
When I initially found this, I was wondering why clippy wasn't just using miri, but after some discussion with some rustc folks let's document why.
changelog: none
We only need to take action when the next block cannot be added to the current
chain, but the logic is much simpler if we express it in terms of when the
block _can_ be added.
Remove support for decompressing dylib metadata
We haven't been compressing dylib metadata for a while now. Removing decompression support will regress error messages about an incompatible rustc version being used, but dylibs are pretty rare anyway.
Fixes https://github.com/rust-lang/rust-analyzer/issues/18451
Use protected visibility when building rustc with LLD
https://github.com/rust-lang/compiler-team/issues/782
I wasn't sure about having two commits in a PR, but I figured, at least initially it might make sense to discuss these commits together. Happy to squash, or move the second commit to a separate PR.
I contemplated trying to enable protected visibility for more cases when LLD will be used other than just `-Zlinker-features=+lld`, but that would be more a complex change that probably still wouldn't cover all cases when LLD is used, so went with the simplest option of just checking if the linker-feature is enabled.
r? lqd
Currently `f32_nan` and `f64_nan` are used to provide the
`invalid_nan_comparison` lint. Since we have `f16_nan` and `f128_nan`,
hook these up so the new float types get the same lints.
