Do not suggest constraining the `&self` param, but rather the return type.
If that is wrong (because it is not sufficient), a follow up error will tell the
user to fix it. This way we lower the chances of *over* constraining, but still
get the cake of "correctly" contrained in two steps.
This is a correct suggestion:
```
error: lifetime may not live long enough
--> $DIR/ex3-both-anon-regions-return-type-is-anon.rs:9:9
|
LL | fn foo<'a>(&self, x: &i32) -> &i32 {
| - - let's call the lifetime of this reference `'1`
| |
| let's call the lifetime of this reference `'2`
LL | x
| ^ method was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
|
help: consider introducing a named lifetime parameter and update trait if needed
|
LL | fn foo<'a>(&self, x: &'a i32) -> &'a i32 {
| ++ ++
```
While this is incomplete because it should suggestino `&'a self`
```
error: lifetime may not live long enough
--> $DIR/ex3-both-anon-regions-self-is-anon.rs:7:19
|
LL | fn foo<'a>(&self, x: &Foo) -> &Foo {
| - - let's call the lifetime of this reference `'1`
| |
| let's call the lifetime of this reference `'2`
LL | if true { x } else { self }
| ^ method was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
|
help: consider introducing a named lifetime parameter and update trait if needed
|
LL | fn foo<'a>(&self, x: &'a Foo) -> &'a Foo {
| ++ ++
```
but the follow up error is
```
error: lifetime may not live long enough
--> tests/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-self-is-anon.rs:7:30
|
6 | fn foo<'a>(&self, x: &'a Foo) -> &'a Foo {
| -- - let's call the lifetime of this reference `'1`
| |
| lifetime `'a` defined here
7 | if true { x } else { self }
| ^^^^ method was supposed to return data with lifetime `'a` but it is returning data with lifetime `'1`
|
help: consider introducing a named lifetime parameter and update trait if needed
|
6 | fn foo<'a>(&'a self, x: &'a Foo) -> &'a Foo {
| ++
```
```
error: lifetime may not live long enough
--> $DIR/lt-ref-self.rs:12:9
|
LL | fn ref_self(&self, f: &u32) -> &u32 {
| - - let's call the lifetime of this reference `'1`
| |
| let's call the lifetime of this reference `'2`
LL | f
| ^ method was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
|
help: consider introducing a named lifetime parameter and update trait if needed
|
LL | fn ref_self<'b>(&'b self, f: &'b u32) -> &'b u32 {
| ++++ ++ ++ ++
```
```
error: lifetime may not live long enough
--> f205.rs:8:16
|
7 | fn resolve_symbolic_reference(&self, reference: Option<Reference>) -> Option<Reference> {
| - --------- has type `Option<Reference<'1>>`
| |
| let's call the lifetime of this reference `'2`
8 | return reference;
| ^^^^^^^^^ method was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
|
help: consider introducing a named lifetime parameter
|
7 | fn resolve_symbolic_reference<'a>(&'a self, reference: Option<Reference<'a>>) -> Option<Reference<'a>> {
| ++++ ++ ++++ ++++
```
The correct suggestion would be
```
help: consider introducing a named lifetime parameter
|
7 | fn resolve_symbolic_reference<'a>(&self, reference: Option<Reference<'a>>) -> Option<Reference<'a>> {
| ++++ ++++ ++++
```
but we are not doing the analysis to detect that yet. If we constrain `&'a self`, then the return type with a borrow will implicitly take its lifetime from `'a`, it is better to make it explicit in the suggestion, in case that `&self` *doesn't* need to be `'a`, but the return does.
```
error: lifetime may not live long enough
--> $DIR/ex3-both-anon-regions-both-are-structs-2.rs:7:5
|
LL | fn foo(mut x: Ref, y: Ref) {
| ----- - has type `Ref<'_, '1>`
| |
| has type `Ref<'_, '2>`
LL | x.b = y.b;
| ^^^^^^^^^ assignment requires that `'1` must outlive `'2`
|
help: consider introducing a named lifetime parameter
|
LL | fn foo<'a>(mut x: Ref<'a, 'a>, y: Ref<'a, 'a>) {
| ++++ ++++++++ ++++++++
```
As can be seen above, it currently doesn't try to compare the `ty::Ty` lifetimes that diverged vs the `hir::Ty` to correctly suggest the following
```
help: consider introducing a named lifetime parameter
|
LL | fn foo<'a>(mut x: Ref<'_, 'a>, y: Ref<'_, 'a>) {
| ++++ ++++++++ ++++++++
```
but I believe this to still be an improvement over the status quo.
CC #40990.
expand: fix minor diagnostics bug
The error mentions `///`, when it's actually `//!`:
```
error[E0658]: attributes on expressions are experimental
--> test.rs:4:9
|
4 | //! wah
| ^^^^^^^
|
= note: see issue https://github.com/rust-lang/rust/issues/15701 <https://github.com/rust-lang/rust/issues/15701> for more information
= help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
= help: `///` is for documentation comments. For a plain comment, use `//`.
```
Enable `rust-lld` on nightly `x86_64-unknown-linux-gnu`
We believe we have done virtually all the internal work and tests we could to prepare for using `lld` as the default linker (at least on Linux). We're IMHO at a point where we'd need to expand testing and coverage in order to make progress on this effort.
Therefore, for further testing and gathering real-world feedback, unexpected issues and use-cases, this PR enables `rust-lld` as the default linker:
- on nightly only (and dev channel)
- on `x86_64-unknown-linux-gnu` only
- when not using an external LLVM (except `download-ci-llvm`), so that distros are not impacted
as described in more detail in this [zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Enabling.20.60rust-lld.60.20on.20nightly.20.60x86_64-unknown-linux-gnu.60/near/433709343).
In case any issues happen to users, as e.g. lld is not bug-for-bug compatible with GNU ld, it's easy to disable with `-Zlinker-features=-lld` to revert to using the system's default linker.
---
I don't know who should review this kind of things, as it's somewhat of a crosscutting effort. Compiler contributor, compiler performance WG and infra member sounds perfect, so r? `@Mark-Simulacrum.`
The last crater run encountered a low number (44) of mainly avoidable issues, like small incompatibilities, user errors, and a difference between the two linkers about which default to use with `--gc-sections`. [Here's the triage report](https://hackmd.io/OAJxlxc6Te6YUot9ftYSKQ?view), categorizing the issues, with some analyses and workarounds. I'd appreciate another set of eyes looking at these results.
The changes in this PR have been test-driven for CI changes, try builds with tests enabled, rustc-perf with bootstrapping, in PR #113382.
For infra, about the CI change: this PR forces `rust.lld` to false on vanilla LLVM builders, just to make sure we have coverage without `rust-lld`. Though to be clear, just using an external LLVM is already enough to keep `rust.lld` to false, in turn reverting everything to using the system's default linker.
cc `@rust-lang/bootstrap` for the bootstrap and config change
cc `@petrochenkov` for the small compiler change
cc `@rust-lang/wg-compiler-performance`
The blog post announcing the change, that we expect to merge around the same time as we merge this PR, is open [on the blog repo](https://github.com/rust-lang/blog.rust-lang.org/pull/1319).
Bootstrap change history: this PR changes the default of a config option on `x86_64-unknown-linux-gnu`. It's, however, not expected to cause issues, or require any changes to existing configurations. It's a big enough change that people should at least know about it, in case it causes unexpected problems. If that happens, set `rust.lld = false` in your `config.toml` (and open an issue).
Fix assertion when attempting to convert `f16` and `f128` with `as`
These types are currently rejected for `as` casts by the compiler. Remove this incorrect check and add codegen tests for all conversions involving these types.
These types are currently rejected for `as` casts by the compiler.
Remove this incorrect check and add codegen tests for all conversions
involving these types.
Rename `${length()}` to `${len()}`
Implements the rename suggested in https://github.com/rust-lang/rust/pull/122808#issuecomment-2047722187
> I brought this up in the doc PR but it belongs here – `length` should probably be renamed `len` before stabilization. The latter is de facto standard in the standard library, whereas the former is only used in a single unstable API. These metafunctions aren’t library items of course, but should presumably still be consistent with established names.
r? `@c410-f3r`
rustdoc: Negative impls are not notable
In #124097, we add `impl !Iterator for [T]` for coherence reasons, and since `Iterator` is a [notable trait](8387315ab3/library/core/src/iter/traits/iterator.rs (L40)), this means that all `-> &[_]` now are tagged with a `!Iterator` impl as a notable trait.
I "fixed" the failing tests in that PR with 6cbbb8b709a43482847243484ed67131e372ba71, where I just blessed the tests, since I didn't want to mix these changes with that PR; however, don't believe negative impls are notable, and this PR aims to prevent these impls from being mentioned.
In the standard library, we use negative impls purely to guide coherence. They're not really a signal of anything useful to the end-user. If there ever is a case that we want negative impls to be mentioned as notable, this really should be an opt-in feature.
Migrate `run-make/no-cdylib-as-rdylib` to `rmake`
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
> "the test will fail if the cdylib is picked, because it doesn't export any rust symbols"
Is that true? Is there a way to verify?
I suggest maybe extending the test with: (after cleaning the directory)
```rust
rustc()
.input("bar.rs")
.crate_type("cdylib")
.run();
rustc()
.input("foo.rs")
.prefer_dynamic()
.run();
fail();
```
to make sure we're actually testing something here.
Fix the dedup error because of spans from suggestion
Fixes#116502
I believe this kind of issue is supposed resolved by #118057, but the `==` in `span` respect syntax context, here we should only care that they point to the same bytes of source text, so should use `source_equal`.
Migrate `run-make/issue-11908` to new `rmake.rs` format
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
Set as draft, because I have a few concerns:
- [x] I am not sure if `target().contains("darwin")` is a good way of checking that the target is on OSX.
- [x] I find it strange that the `dylib` part of the test adapts to different target platforms, but not the `rlib` part. Is `rlib` named the same on all platforms?
Rollup of 7 pull requests
Successful merges:
- #119838 (style-guide: When breaking binops handle multi-line first operand better)
- #124844 (Use a proper probe for shadowing impl)
- #125047 (Migrate `run-make/issue-14500` to new `rmake.rs` format)
- #125080 (only find segs chain for missing methods when no available candidates)
- #125088 (Uplift `AliasTy` and `AliasTerm`)
- #125100 (Don't do post-method-probe error reporting steps if we're in a suggestion)
- #125118 (Use new utility functions/methods in run-make tests)
r? `@ghost`
`@rustbot` modify labels: rollup
Use new utility functions/methods in run-make tests
Little cleanup using new functions/methods I added into the `run-make-support` library.
r? `@jieyouxu`
Don't do post-method-probe error reporting steps if we're in a suggestion
Currently in method probing, if we fail to pick a method, then we reset and try to collect relevant candidates for method errors:
34582118af/compiler/rustc_hir_typeck/src/method/probe.rs (L953-L993)
However, we do method lookups via `lookup_method_for_diagnostic` and only care about the result if the method probe was a *success*.
Namely, we don't need to do a bunch of other lookups on failure, since we throw away these results anyways, such as an expensive call to:
34582118af/compiler/rustc_hir_typeck/src/method/probe.rs (L959)
And:
34582118af/compiler/rustc_hir_typeck/src/method/probe.rs (L985)
---
This PR also renames some methods so it's clear that they're for diagnostics.
r? `@nnethercote`
only find segs chain for missing methods when no available candidates
Fixes#124946
This PR includes two changes:
- Extracting the lookup for the missing method in chains into a single function.
- Calling this function only when there are no candidates available.
Migrate `run-make/issue-14500` to new `rmake.rs` format
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
Note: I find suspicious that `libbar.a` is hardcoded and is not using the `STATICLIB` call to adapt to Windows platforms. Is this intentional? If not, this will need to be changed.
