Consolidate and improve error messaging for `CoerceUnsized` and `DispatchFromDyn`
Firstly, this PR consolidates and reworks the error diagnostics for `CoercePointee` and `DispatchFromDyn`. There was a ton of duplication for no reason -- this reworks both the errors and also the error codes, since they can be shared between both traits since they report the same thing.
Secondly, when encountering a struct with multiple fields that must be coerced, point out the field spans, rather than mentioning the fields by name. This makes the error message clearer, but also means that we don't mention the `__S` dummy parameter for `derive(CoercePointee)`.
Thirdly, emit a custom error message when we encounter a trait error that comes from the recursive field `CoerceUnsized`/`DispatchFromDyn` trait check. **Note:** This is the only one I'm not too satisfied with -- I think it could use some more refinement, but ideally it explains that the field must be an unsize-able pointer... Feedback welcome.
Finally, don't emit `DispatchFromDyn` validity errors if we detect `CoerceUnsized` validity errors from an impl of the same ADT.
This is best reviewed per commit.
r? `@oli-obk` perhaps?
cc `@dingxiangfei2009` -- sorry for making my own attempt at this PR, but I wanted to see if I could implement a fix for #136796 in a less complicated way, since communicating over github review comments can be a bit slow. I'll leave comments inline to explain my thinking about the diagnostics changes.
Remove `feature(dyn_compatible_for_dispatch)` from the compiler
This PR proposes the removal of `feature(dyn_compatible_for_dispatch)` from the compiler.
* As far as I can tell from the tracking issue, there's very little demand for this feature. I think that if this feature becomes useful in the future, then a fresh implementation from a fresh set of eyes, with renewed understanding of how this feature fits into the picture of Rust as it exists **today** would be great to have; however, in the absence of this demand, I don't see a particularly good reason to keep this implementation around.
* The RFC didn't receive very much discussion outside of the lang team, and while the discussion it received seemed to suggest that this feature was aiming to simplify the language and improve expressibility, I don't think this feature has really demonstrated either of those goals in practice. Furthermore, nobody seems to have owned this feature for quite some time or express desire to push for its stabilization.
* Relatedly, I find some of the RFC discussion like "when we make things impossible it's often presumptuous"[^1] and "I tend to want to take a 'we are all adults here' attitude toward unsafe code"[^2] to be particularly uncompelling. Of course this is no criticism to the authors of those comments since they're pretty old comments now, but type soundness is (IMO) the primary goal of the types team. This feature doesn't really do much other than further complicating the story of where we must validate object safety for soundness, along making dyn-incompatible trait object types *almost* seem useful, but very much remain UB to create and misleading to users who don't know better.
* Dyn compatibility's story has gotten more complicated since the feature was proposed in 2017, and now it needs to interact with things like associated consts, GATs, RPITITs, trait upcasting, `dyn*`, etc. While some of this is exercised in the codebase today, I'm not confident all of the corners of this feature have been hammered out. Reducing the "surface area" for what can go wrong in the compiler, especially around a side of the language (`dyn Trait`) that has been known to be particularly unsound in the past, seems good enough motivation to get rid of this for now.
[^1]: https://github.com/rust-lang/rfcs/pull/2027#issuecomment-307592857
[^2]: https://github.com/rust-lang/rfcs/pull/2027#issuecomment-307645838
cc `@rust-lang/types` `@rust-lang/lang`
Tracking:
- #43561
r? types
Rollup of 10 pull requests
Successful merges:
- #136610 (Allow `IndexSlice` to be indexed by ranges.)
- #136991 ([rustdoc] Add new setting to wrap source code lines when too long)
- #137061 (Unstable `gen_future` Feature Tracking )
- #137393 (Stabilize `unbounded_shifts`)
- #137482 (Windows: use existing wrappers in `File::open_native`)
- #137484 (Fix documentation for unstable sort on slice)
- #137491 (Tighten `str-to-string-128690.rs``CHECK{,-NOT}`s to make it less likely to incorrectly fail with symbol name mangling)
- #137495 (Added into_value function to ControlFlow<T, T>)
- #137501 (Move `impl` blocks out of `rustc_middle/src/mir/syntax.rs`)
- #137505 (Add a span to `CompilerBuiltinsCannotCall`)
r? `@ghost`
`@rustbot` modify labels: rollup
Add a span to `CompilerBuiltinsCannotCall`
Currently, this error emit a diagnostic with no context like:
error: `compiler_builtins` cannot call functions through upstream monomorphizations; encountered invalid call from `<math::libm::support::hex_float::Hexf<i32> as core::fmt::LowerHex>::fmt` to `core::fmt::num::<impl core::fmt::LowerHex for i32>::fmt`
With this change, it at least usually points to the problematic function:
error: `compiler_builtins` cannot call functions through upstream monomorphizations; encountered invalid call from `<math::libm::support::hex_float::Hexf<i32> as core::fmt::LowerHex>::fmt` to `core::fmt::num::<impl core::fmt::LowerHex for i32>::fmt`
--> src/../libm/src/math/support/hex_float.rs:270:5
|
270 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
Tighten `str-to-string-128690.rs``CHECK{,-NOT}`s to make it less likely to incorrectly fail with symbol name mangling
The `invoke` to match on to `CHECK` or `CHECK-NOT` (latest master) looks like
```llvm
%_0.i.i.i.i.i.i.i.i.i.i.i.i.i1.i = invoke noundef zeroext i1 ``@"_ZN42_$LT$str$u20$as$u20$core..fmt..Display$GT$3fmt17ha18033e7fb4f14fcE"(ptr`` noalias noundef nonnull readonly align 1 %_3.val.i.i.i.i.i.i.i.i.i.i.i.i.i, i64 noundef %_3.val1.i.i.i.i.i.i.i.i.i.i.i.i.i, ptr noalias noundef nonnull align 8 dereferenceable(64) %formatter.i)
to label %bb1.i unwind label %cleanup.i, !noalias !80
```
in the local `.ll` output.
This test incorrectly failed in https://github.com/rust-lang/rust/pull/137483#issuecomment-2676925819 due to
```
// CHECK-NOT: {{(call|invoke).*}}fmt
```
matching against the unrelated call
```llvm
tail call void ``@_RNvNtCseLfmtnDCoTB_5alloc7raw_vec12handle_error``
```
It's not pretty by any means, but...
r? ``@saethlin``
Windows: use existing wrappers in `File::open_native`
Just a small improvement I've noticed - prevents accidents regarding `SetFileInformationByHandle` parameters.
Probably ``@ChrisDenton`` since we talked about it on discord :)
Unstable `gen_future` Feature Tracking
This PR removes the reference to the closed tracking issue **#50547** for the `gen_future` feature. Since `gen_future` is an internal feature used in async block desugaring, it does not require a public tracking issue.
#### Changes:
- Replaced `issue = "50547"` with `issue = "none"` in **library/core/src/future/mod.rs**.
- Ensures that it is correctly identified as an internal feature.
#### Rationale:
With this change, the Unstable Book will now state:
> *"This feature has no tracking issue and is therefore likely internal to the compiler, not being intended for general use."*
Closes **#76249**. 🚀🦀
Allow `IndexSlice` to be indexed by ranges.
This comes with some annoyances as the index type can no longer inferred from indexing expressions. The biggest offender for this is `IndexVec::from_fn_n(|idx| ..., n)` where the index type won't be inferred from the call site or any index expressions inside the closure.
My main use case for this is mapping a `Place` to `Range<Idx>` for value tracking where the range represents all the values the place contains.
librustdoc: Use `pulldown-cmark-escape` for HTML escaping
Implementation of `@notriddle` 's [suggestion](https://github.com/rust-lang/rust/pull/137274#issuecomment-2669001585).
Somewhat related to #137274 , but the two PRs should be complementary.
Local perf results look like a nice improvement! (so would love a perf run on the CI)
Currently, this error emit a diagnostic with no context like:
error: `compiler_builtins` cannot call functions through upstream monomorphizations; encountered invalid call from `<math::libm::support::hex_float::Hexf<i32> as core::fmt::LowerHex>::fmt` to `core::fmt::num::<impl core::fmt::LowerHex for i32>::fmt`
With this change, it at least usually points to the problematic
function:
error: `compiler_builtins` cannot call functions through upstream monomorphizations; encountered invalid call from `<math::libm::support::hex_float::Hexf<i32> as core::fmt::LowerHex>::fmt` to `core::fmt::num::<impl core::fmt::LowerHex for i32>::fmt`
--> src/../libm/src/math/support/hex_float.rs:270:5
|
270 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
Emit getelementptr inbounds nuw for pointer::add()
Lower pointer::add (via intrinsic::offset with unsigned offset) to getelementptr inbounds nuw on LLVM versions that support it. This lets LLVM make use of the pre-condition that the offset addition does not wrap in an unsigned sense. Together with inbounds, this also implies that the offset is non-negative.
Fixes https://github.com/rust-lang/rust/issues/137217.
Fixed issue with usage of generics and moved feature gate to crate root
Removed const tag
Fixed alphabetical ordering of feature gate, added same to doctest
Removed crate-level declaration of feature gate control_flow_into_value
Used const_precise_live_drops to constify into_value without issue of a drop
avoid `compiler_for` for dist tools and force the current compiler
Using `compiler_for` in dist steps was causing to install stage1 tools into the dist tarballs, which doesn't match with the stage2 compiler.
Fixes https://github.com/rust-lang/rust/issues/137469
FIx `sym` -> `syn` typo in tail-expr-drop-order type opt-out
The #131326 PR attempts to reduce some false positives for the `tail_expr_drop_order` lint by hard-coding some common ecosystem crate names. Specifically, I believe it attempts to opt out the drop impls from `syn` which only exist as optimizations.
However, this was typo'd like "sym", which is a crate that has been [yanked](https://crates.io/crates/sym) (lol). This PR fixes that.
cc `@dingxiangfei2009` `@nikomatsakis` -- did I mistake this? Was this meant to be a different crate?
`@bors` rollup
Fix rustdoc test directives that were accidentally ignored 🧐
Replace "// `@"` with "//@ ", and fix the tests so they actually pass, after directives are checked.
~~Only the first commit is mandatory, other two are small drive-bys.~~
intrinsics: unify rint, roundeven, nearbyint in a single round_ties_even intrinsic
LLVM has three intrinsics here that all do the same thing (when used in the default FP environment). There's no reason Rust needs to copy that historically-grown mess -- let's just have one intrinsic and leave it up to the LLVM backend to decide how to lower that.
Suggested by `@hanna-kruppe` in https://github.com/rust-lang/rust/issues/136459; Cc `@tgross35`
try-job: test-various
Misc. `rustc_codegen_ssa` cleanups 🧹
Just a bunch of stuff I found while reading the crate's code.
Each commit can stand on its own.
Maybe r? `@Noratrieb` because I saw you did some similar cleanups on these files a while ago? (feel free to re-assign, I'm just guessing)
vectorcall ABI: require SSE2
According to the official docs at https://learn.microsoft.com/en-us/cpp/cpp/vectorcall, SSE2 is required for this ABI. Add a check that enforces this.
I put this together with the other checks ensuring the target features required for a function are present... however, since the ABI is known pre-monomorphization, it would be possible to do this check earlier, which would have the advantage of checking even in `cargo check`. It would have the disadvantage of spreading this code in yet more places.
The first commit just does a little refactoring of the mono-time ABI check to make it easier to add the new check.
Cc `@workingjubilee`
try-job: dist-i586-gnu-i586-i686-musl
