Remove `SymbolStr`
This was originally proposed in https://github.com/rust-lang/rust/pull/74554#discussion_r466203544. As well as removing the icky `SymbolStr` type, it allows the removal of a lot of `&` and `*` occurrences.
Best reviewed one commit at a time.
r? `@oli-obk`
Re-introduce concept of projection cache 'completion'
Instead of clearing out the cache entirely, we store
the intermediate evaluation result into the cache entry.
This accomplishes several things:
* We avoid the performance hit associated with re-evaluating
the sub-obligations
* We avoid causing issues with incremental compilation, since
the final evaluation result is always the same
* We avoid affecting other uses of the same `InferCtxt` which
might care about 'side effects' from processing the sub-obligations
(e,g. region constraints). Only code that is specifically aware
of the new 'complete' code is affected
Instead of clearing out the cache entirely, we store
the intermediate evaluation result into the cache entry.
This accomplishes several things:
* We avoid the performance hit associated with re-evaluating
the sub-obligations
* We avoid causing issues with incremental compilation, since
the final evaluation result is always the same
* We avoid affecting other uses of the same `InferCtxt` which
might care about 'side effects' from processing the sub-obligations
(e,g. region constraints). Only code that is specifically aware
of the new 'complete' code is affected
Add user seed to `-Z randomize-layout`
Allows users of -`Z randomize-layout` to provide `-Z layout-seed=<seed>` in order to further randomizing type layout randomization. Extension of [compiler-team/#457](https://github.com/rust-lang/compiler-team/issues/457), allows users to change struct layouts without changing code and hoping that item path hashes change, aiding in detecting layout errors
Avoid sorting in hash map stable hashing
Suggested by `@the8472` [here](https://github.com/rust-lang/rust/pull/89404#issuecomment-991813333). I hope that I understood it right, I replaced the sort with modular multiplication, which should be commutative.
Can I ask for a perf. run? However, locally it didn't help at all. Creating the `StableHasher` all over again is probably slowing it down quite a lot. And using `FxHasher` is not straightforward, because the keys and values only implement `HashStable` (and probably they shouldn't be just hashed via `Hash` anyway for it to actually be stable).
Maybe the `StableHash` interface could be changed somehow to better suppor these scenarios where the hasher is short-lived. Or the `StableHasher` implementation could have variants with e.g. a shorter buffer for these scenarios.
Rollup of 7 pull requests
Successful merges:
- #91566 (Apply path remapping to DW_AT_GNU_dwo_name when producing split DWARF)
- #91926 (Remove `in_band_lifetimes` from `rustc_metadata`)
- #91931 (Remove `in_band_lifetimes` from `rustc_codegen_llvm`)
- #92024 (rustc_codegen_llvm: Give each codegen unit a unique DWARF name on all platforms, not just Apple ones.)
- #92037 (Use a const ParamEnv when in default_method_body_is_const)
- #92047 (Set `RUST_BACKTRACE=0` when running location-detail tests)
- #92050 (Add a space and 2 grave accents )
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
For a data section, the object crate will set the SHF_ALLOC by
default, which is exactly what we don't want. Explicitly set
sh_flags to zero to avoid this.
Fixes#92073
There's not really anything we can do with them, and they're
causing ICEs. I'm not using a wildcard match, as we should check
that any new `PredicateKind`s are handled properly by rustdoc.
Rollup of 7 pull requests
Successful merges:
- #91858 (pass -Wl,-z,origin to set DF_ORIGIN when using rpath)
- #91923 (Remove `in_band_lifetimes` from `rustc_query_impl`)
- #91925 (Remove `in_band_lifetimes` from `rustc_privacy`)
- #91977 (Clean up search code and unify function returned values)
- #92018 (Fix typo in "new region bound" suggestion)
- #92022 (Eliminate duplicate codes of expected_found_bool)
- #92032 (hir: Do not introduce dummy type names for `extern` blocks in def paths)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Use a const ParamEnv when in default_method_body_is_const
r? `@oli-obk`
This PR fixes the param_env function to return `constness: Const` correctly for trait methods marked with `#[default_method_body_is_const]`. The snippet below is erroneously accepted by the compiler and has been fixed by this change. ([Playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=12dc6681b2eeee5f604203d96259eeb4))
```rust
#![feature(const_fn_trait_bound)]
#![feature(const_trait_impl)]
trait Tr {}
impl Tr for () {}
const fn foo<T>() where T: ~const Tr {}
pub trait Foo {
#[default_method_body_is_const]
fn foo() {
foo::<()>();
}
}
```
rustc_codegen_llvm: Give each codegen unit a unique DWARF name on all platforms, not just Apple ones.
To avoid breaking split DWARF, we need to ensure that each codegen unit has a
unique `DW_AT_name`. This is because there's a remote chance that different
codegen units for the same module will have entirely identical DWARF entries
for the purpose of the DWO ID, which would violate Appendix F ("Split Dwarf
Object Files") of the DWARF 5 specification. LLVM uses the algorithm specified
in section 7.32 "Type Signature Computation" to compute the DWO ID, which does
not include any fields that would distinguish compilation units. So we must
embed the codegen unit name into the `DW_AT_name`.
Closes#88521.
Remove `in_band_lifetimes` from `rustc_codegen_llvm`
See #91867 for more information.
This one took a while. This crate has dozens of functions not associated with any type, and most of them were using in-band lifetimes for `'ll` and `'tcx`.
Apply path remapping to DW_AT_GNU_dwo_name when producing split DWARF
`--remap-path-prefix` doesn't apply to paths to `.o` (in case of packed) or `.dwo` (in case of unpacked) files in `DW_AT_GNU_dwo_name`. GCC also has this bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91888
hir: Do not introduce dummy type names for `extern` blocks in def paths
Use a separate nameless `DefPathData` variant instead.
Extracted from https://github.com/rust-lang/rust/pull/91795.
pass -Wl,-z,origin to set DF_ORIGIN when using rpath
DF_ORIGIN flag signifies that the object being loaded may make reference to the $ORIGIN substitution string.
Some implementations are just ignoring [DF_ORIGIN](http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#df_flags) and do [substitution](http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#substitution) for $ORIGIN if present (whatever DF_ORIGIN presence or not) like glibc. But some others mandate the present of DF_ORIGIN for the substitution (like OpenBSD).
Set the flag inconditionally if rpath is wanted.
One possible fallout is if the linker rejects `-z origin` option.
Improve suggestion to change struct field to &mut
r? ``@estebank``
Now displays a proper underline style suggestion instead of including the code change inline with the message.
Move generator check earlier in inlining.
Inlining into generator may create references to other generators. For instance, inlining `Pin::<&mut from_generator::GenFuture<[generator1]>>::new_unchecked` into `generator2`. This cross reference can then create cycles when computing inlining for `generator1`.
In order to avoid this kind of surprises, we forbid all inlining into generators, and rely on LLVM to do the right thing. The existing `remove-zst-query-cycle` already ICEs in inline-mir mode, so we use it as test.
Split from #91743.
Show the unused type for `unused_results` lint
I think it's helpful to know what type was unused when looking at these
warnings. The type will likely determine whether the result *should* be
used, or whether it should just be ignored.
Including the type also matches the behavior of the `must_use` lint:
unused `SomeType` that must be used.
Lint bare traits in AstConv.
Removing the lint from lowering allows to:
- make lowering querification easier;
- have the lint implementation in only one place.
r? `@estebank`
Fix suggestion of additional `pub` when using `pub pub fn ...`
Fix#87694.
Marked as draft to start with because I want to explore doing the same fix for `const const fn` and other repeated-but-valid keywords.
`@rustbot` label A-diagnostics D-invalid-suggestion T-compiler
Implement let-else type annotations natively
Tracking issue: #87335Fixes#89688, fixes#89807, edit: fixes #89960 as well
As explained in https://github.com/rust-lang/rust/issues/89688#issuecomment-940405082, the previous desugaring moved the let-else scrutinee into a dummy variable, which meant if you wanted to refer to it again in the else block, it had moved.
This introduces a new hir type, ~~`hir::LetExpr`~~ `hir::Let`, which takes over all the fields of `hir::ExprKind::Let(...)` and adds an optional type annotation. The `hir::Let` is then treated like a `hir::Local` when type checking a function body, specifically:
* `GatherLocalsVisitor` overrides a new `Visitor::visit_let_expr` and does pretty much exactly what it does for `visit_local`, assigning a local type to the `hir::Let` ~~(they could be deduplicated but they are right next to each other, so at least we know they're the same)~~
* It reuses the code in `check_decl_local` to typecheck the `hir::Let`, simply returning 'bool' for the expression type after doing that.
* ~~`FnCtxt::check_expr_let` passes this local type in to `demand_scrutinee_type`, and then imitates check_decl_local's pattern checking~~
* ~~`demand_scrutinee_type` (the blindest change for me, please give this extra scrutiny) uses this local type instead of of creating a new one~~
* ~~Just realised the `check_expr_with_needs` was passing NoExpectation further down, need to pass the type there too. And apparently this Expectation API already exists.~~
Some other misc notes:
* ~~Is the clippy code supposed to be autoformatted? I tried not to give huge diffs but maybe some rustfmt changes simply haven't hit it yet.~~
* in `rustc_ast_lowering/src/block.rs`, I noticed some existing `self.alias_attrs()` calls in `LoweringContext::lower_stmts` seem to be copying attributes from the lowered locals/etc to the statements. Is that right? I'm new at this, I don't know.
Performing 'speculative evaluation' introduces caching bugs that
cannot be fixed without invasive changes to projection.
Hopefully, we can win back most of the performance lost by
re-adding 'cache completion'
Fixes#90662
Previously it hid all non-macro names from other crates.
This has no relation to linking and can change name resolution behavior in some cases (e.g. glob conflicts), in addition to just producing the "unresolved name" errors
DF_ORIGIN flag signifies that the object being loaded may make reference to the $ORIGIN substitution string.
Some implementations are just ignoring DF_ORIGIN and do substitution for $ORIGIN if present (whatever DF_ORIGIN pr
Set the flag inconditionally if rpath is wanted.
platforms, not just Apple ones.
To avoid breaking split DWARF, we need to ensure that each codegen unit has a
unique `DW_AT_name`. This is because there's a remote chance that different
codegen units for the same module will have entirely identical DWARF entries
for the purpose of the DWO ID, which would violate Appendix F ("Split Dwarf
Object Files") of the DWARF 5 specification. LLVM uses the algorithm specified
in section 7.32 "Type Signature Computation" to compute the DWO ID, which does
not include any fields that would distinguish compilation units. So we must
embed the codegen unit name into the `DW_AT_name`.
Closes#88521.
Implement normalize_erasing_regions queries in terms of 'try' version
Attempt to lessen performance regression caused by https://github.com/rust-lang/rust/pull/91255
r? `@jackh726`
This will cause backtraces to point to the location of
the field in the struct/enum, rather than the derive macro.
This makes it clear which field was being decoded when the
backtrace was captured (which is especially useful if
there are multiple fields with the same type).
remove a empty line
import `module_to_string`
use `contains("test")`
show a suggestion in case module starts_with/ends_with "test"
replace `parent` with `containing`
See #91867
This was mostly straightforward. In several places, I take advantage
of the fact that lifetimes are non-hygenic: a macro declares the
'tcx' lifetime, which is then used in types passed in as macro
arguments.
extend `simplify_type`
might cause a slight perf inprovement and imo more accurately represents what types there are.
considering that I was going to use this in #85048 it seems like we might need this in the future anyways 🤷
Make `TyS::is_suggestable` check for non-suggestable types structually
Not sure if I went overboard checking substs in dyn types, etc. Let me know if I should simplify this function.
Fixes#91832
Remove `in_band_lifetimes` from `rustc_codegen_ssa`
See #91867 for more information.
In `compiler/rustc_codegen_ssa/src/coverageinfo/map.rs`, there are several functions with an explicit `'a` lifetime but only a single `&'a self` parameter. These lifetimes should be redundant given lifetime elision, unless the existential `impl Iterator` has weird issues regarding that. Should the redundant lifetimes be removed?
Handle unordered const/ty generics for object lifetime defaults
*feel like I should have a PR description but cant think of what to put here*
r? ```@lcnr```
By changing `as_str()` to take `&self` instead of `self`, we can just
return `&str`. We're still lying about lifetimes, but it's a smaller lie
than before, where `SymbolStr` contained a (fake) `&'static str`!
Stabilize `iter::zip`
Hello all!
As the tracking issue (#83574) for `iter::zip` completed the final commenting period without any concerns being raised, I hereby submit this stabilization PR on the issue.
As the pull request that introduced the feature (#82917) states, the `iter::zip` function is a shorter way to zip two iterators. As it's generally a quality-of-life/ergonomic improvement, it has been integrated into the codebase without any trouble, and has been
used in many places across the rust compiler and standard library since March without any issues.
For more details, I would refer to `@cuviper's` original PR, or the [function's documentation](https://doc.rust-lang.org/std/iter/fn.zip.html).
Revert setting a default for the MACOSX_DEPLOYMENT_TARGET env var for linking
This reverts commit b376f5621b, which is the main part of #90499, because it turns out that this causes a good amount of breakage in crates relying on the old behavior. In particular `winit`, `coreaudio` and crates that depend on them are affected. Fixes#91372.
Background:
Before #90499 the behavior was the following: If MACOSX_DEPLOYMENT_TARGET is not set, we pass the minimum supported OS version to LLVM but not to the linker. The linker default depends on the Xcode version and the version of the OS it is running on. That caused one known problem in libcurl with the most recent Xcode versions. #90499 passed the minumum supported version (10.7 for Macos x86-64) to the linker instead. This has shown to be problematic because some crates such as winit, coreaudio implicitly expect a newer minimum OS version. The libcurl issue has been fixed independently (see https://github.com/alexcrichton/curl-rust/issues/417), so a revert should not really be problematic.
Eventually we should probably mimic clang's behavior and fall back to the default of the currently configured Macos SDK for both the LLVM min os target version and MACOSX_DEPLOYMENT_TARGET for linking. That would entail looking at the `Version` property of the `SDKSettings.json` in the currently configured SDK.
Use `OutputFilenames` to generate output file for `-Zllvm-time-trace`
The resulting profile will include the crate name and will be stored in
the `--out-dir` directory.
This implementation makes it convenient to use LLVM time trace together
with cargo, in the contrast to the previous implementation which would
overwrite profiles or store them in `.cargo/registry/..`.
Tweak errors coming from `for`-loop, `?` and `.await` desugaring
* Suggest removal of `.await` on non-`Future` expression
* Keep track of obligations introduced by desugaring
* Remove span pointing at method for obligation errors coming from desugaring
* Point at called local sync `fn` and suggest making it `async`
```
error[E0277]: `()` is not a future
--> $DIR/unnecessary-await.rs:9:10
|
LL | boo().await;
| -----^^^^^^ `()` is not a future
| |
| this call returns `()`
|
= help: the trait `Future` is not implemented for `()`
help: do not `.await` the expression
|
LL - boo().await;
LL + boo();
|
help: alternatively, consider making `fn boo` asynchronous
|
LL | async fn boo () {}
| +++++
```
Fix#66731.
Stabilize asm! and global_asm!
Tracking issue: #72016
It's been almost 2 years since the original [RFC](https://github.com/rust-lang/rfcs/pull/2850) was posted and we're finally ready to stabilize this feature!
The main changes in this PR are:
- Removing `asm!` and `global_asm!` from the prelude as per the decision in #87228.
- Stabilizing the `asm` and `global_asm` features.
- Removing the unstable book pages for `asm` and `global_asm`. The contents are moved to the [reference](https://github.com/rust-lang/reference/pull/1105) and [rust by example](https://github.com/rust-lang/rust-by-example/pull/1483).
- All links to these pages have been removed to satisfy the link checker. In a later PR these will be replaced with links to the reference or rust by example.
- Removing the automatic suggestion for using `llvm_asm!` instead of `asm!` if you're still using the old syntax, since it doesn't work anymore with `asm!` no longer being in the prelude. This only affects code that predates the old LLVM-style `asm!` being renamed to `llvm_asm!`.
- Updating `stdarch` and `compiler-builtins`.
- Updating all the tests.
r? `@joshtriplett`
Looser check for overflowing_binary_op
Fix for issue #91636 tight check resulted in ICE, this makes the check a little looser. It seems `eq` allows comparing of `supertype` and `subtype` if `lhs = supertype` and `rhs = subtype` but not vice versa, is this intended behavior ?
Return an error when `eval_rvalue_with_identities` fails
Previously some code paths would fail to evaluate the rvalue, while
incorrectly indicating success with `Ok`. As a result the previous value
of lhs could have been incorrectly const propagated.
Fixes#91725.
r? `@oli-obk`
Recover on invalid operators `<>` and `<=>`
Thanks to #89871 for showing me how to do this.
Next, I think it'd be nice to recover on `<=>` too, like #89871 intended, if this even works.
Previously some code paths would fail to evaluate the rvalue, while
incorrectly indicating success with `Ok`. As a result the previous value
of lhs could have been incorrectly const propagated.
Suggest to specify a target triple when lang item is missing
It is very common for newbies to embedded to hit this confusing error when forgetting to specify the target.
Source: me googling this error many times.
## Possible changes
* We could possibly restrict the note+help to only be included on eh_personality lang item if that helped reduce false positives, but its also possible doing so would just increase false negatives
* Open to any suggestions on rewriting the messages
* We could possibly remove the `.cargo/config` alternative to avoid the message getting too noisy but I think its valuable to have as its the correct approach for most embedded projects so that `cargo build` just works.
r? rust-lang/diagnostics
manually implement `Hash` for `DefId`
This might speed up hashing for hashers that can work on individual u64s. Just as an experiment, suggested in a reddit thread on `FxHasher`. cc `@nnethercote`
Note that this should not be merged as is without cfg-ing the code path for 64 bits.
This crate actually had a typo `'ctx` in one of its functions:
```diff
-pub fn same_type_modulo_infer(a: Ty<'tcx>, b: Ty<'ctx>) -> bool {
+pub fn same_type_modulo_infer<'tcx>(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
```
This reverts commit b376f5621b, which is
the main part of #90499, because it turns out that this causes a good
amount of breakage in crates relying on the old behavior.
Fixes#91372.
GATs outlives lint: Try to prove bounds
Fixes#91036Fixes#90888Fixes#91348 (better error + documentation to be added to linked issue)
Instead of checking for bounds directly, try to prove them in the associated type environment.
Also, add a bit of extra information to the error, including a link to the relevant discussion issue (#87479). That should be edited to include a brief summary of the current state of the outlives lint, including a brief background. It also might or might not be worth it to bump this to a full error code at some point.
r? ``@nikomatsakis``
Use module inline assembly to embed bitcode
In LLVM 14, our current method of setting section flags to avoid
embedding the `.llvmbc` section into final compilation artifacts
will no longer work, see issue #90326. The upstream recommendation
is to instead embed the entire bitcode using module-level inline
assembly, which is what this change does.
I've kept the existing code for platforms where we do not need to
set section flags, but possibly we should always be using the
inline asm approach (which would have to look a bit different for MachO).
r? `@nagisa`
The resulting profile will include the crate name and will be stored in
the `--out-dir` directory.
This implementation makes it convenient to use LLVM time trace together
with cargo, in the contrast to the previous implementation which would
overwrite profiles or store them in `.cargo/registry/..`.
replace dynamic library module with libloading
This PR deletes the `rustc_metadata::dynamic_lib` module in favor of the popular and better tested [`libloading` crate](https://github.com/nagisa/rust_libloading/).
We don't benefit from `libloading`'s symbol lifetimes since we end up leaking the loaded library in all cases, but the call-sites look much nicer by improving error handling and abstracting away some transmutes. We also can remove `rustc_metadata`'s direct dependencies on `libc` and `winapi`.
This PR also adds an exception for `libloading` (and its license) to tidy, so this will need sign-off from the compiler team.
Stabilise `feature(const_generics_defaults)`
`feature(const_generics_defaults)` is complete implementation wise and has a pretty extensive test suite so I think is ready for stabilisation.
needs stabilisation report and maybe an RFC 😅
r? `@lcnr`
cc `@rust-lang/project-const-generics`
They are also removed from the prelude as per the decision in
https://github.com/rust-lang/rust/issues/87228.
stdarch and compiler-builtins are updated to work with the new, stable
asm! and global_asm! macros.
Slightly optimize hash map stable hashing
I was profiling some of the `rustc-perf` benchmarks locally and noticed that quite some time is spent inside the stable hash of hashmaps. I tried to use a `SmallVec` instead of a `Vec` there, which helped very slightly.
Then I tried to remove the sorting, which was a bottleneck, and replaced it with insertion into a binary heap. Locally, it yielded nice improvements in instruction counts and RSS in several benchmarks for incremental builds. The implementation could probably be much nicer and possibly extended to other stable hashes, but first I wanted to test the perf impact properly.
Can I ask someone to do a perf run? Thank you!
I think it's helpful to know what type was unused when looking at these
warnings. The type will likely determine whether the result *should* be
used, or whether it should just be ignored.
Including the type also matches the behavior of the `must_use` lint:
unused `SomeType` that must be used.
Rollup of 8 pull requests
Successful merges:
- #90081 (Make `intrinsics::write_bytes` const)
- #91643 (asm: Allow using r9 (ARM) and x18 (AArch64) if they are not reserved by the current target)
- #91737 (Make certain panicky stdlib functions behave better under panic_immediate_abort)
- #91750 (rustdoc: Add regression test for Iterator as notable trait on &T)
- #91764 (Do not ICE when suggesting elided lifetimes on non-existent spans.)
- #91780 (Remove hir::Node::hir_id.)
- #91797 (Fix zero-sized reference to deallocated memory)
- #91806 (Make `Unique`s methods `const`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
asm: Allow using r9 (ARM) and x18 (AArch64) if they are not reserved by the current target
This supersedes https://github.com/rust-lang/rust/pull/88879.
cc `@Skirmisher`
r? `@joshtriplett`
Tweak assoc type obligation spans
* Point at RHS of associated type in obligation span
* Point at `impl` assoc type on projection error
* Reduce verbosity of recursive obligations
* Point at source of binding lifetime obligation
* Tweak "required bound" note
* Tweak "expected... found opaque (return) type" labels
* Point at set type in impl assoc type WF errors
r? `@oli-obk`
This is a(n uncontroversial) subset of #85799.
Point at capture points for non-`'static` reference crossing a `yield` point
```
error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
--> $DIR/issue-72312.rs:10:24
|
LL | pub async fn start(&self) {
| ^^^^^ this data with an anonymous lifetime `'_`...
...
LL | require_static(async move {
| -------------- ...is required to live as long as `'static` here...
LL | &self;
| ----- ...and is captured here
|
note: `'static` lifetime requirement introduced by this trait bound
--> $DIR/issue-72312.rs:2:22
|
LL | fn require_static<T: 'static>(val: T) -> T {
| ^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0759`.
```
Fix#72312.
Suggest using a temporary variable to fix borrowck errors
Fixes#77834.
In Rust, nesting method calls with both require `&mut` access to `self`
produces a borrow-check error:
error[E0499]: cannot borrow `*self` as mutable more than once at a time
--> src/lib.rs:7:14
|
7 | self.foo(self.bar());
| ---------^^^^^^^^^^-
| | | |
| | | second mutable borrow occurs here
| | first borrow later used by call
| first mutable borrow occurs here
That's because Rust has a left-to-right evaluation order, and the method
receiver is passed first. Thus, the argument to the method cannot then
mutate `self`.
There's an easy solution to this error: just extract a local variable
for the inner argument:
let tmp = self.bar();
self.foo(tmp);
However, the error doesn't give any suggestion of how to solve the
problem. As a result, new users may assume that it's impossible to
express their code correctly and get stuck.
This commit adds a (non-structured) suggestion to extract a local
variable for the inner argument to solve the error. The suggestion uses
heuristics that eliminate most false positives, though there are a few
false negatives (cases where the suggestion should be emitted but is
not). Those other cases can be implemented in a future change.
Improve the readability of `List<T>`.
This commit does the following.
- Expands on some of the things already mentioned in comments.
- Describes the uniqueness assumption, which is critical but wasn't
mentioned at all.
- Rewrites `empty()` into a clearer form, as provided by Daniel
Henry-Mantilla on Zulip.
- Reorders things slightly so that more important things
are higher up, and incidental things are lower down, which makes
reading the code easier.
r? ````@lcnr````
* Point at RHS of associated type in obligation span
* Point at `impl` assoc type on projection error
* Reduce verbosity of recursive obligations
* Point at source of binding lifetime obligation
* Tweak "required bound" note
* Tweak "expected... found opaque (return) type" labels
* Point at set type in impl assoc type WF errors
Bump rmeta version to fix rustc_serialize ICE
#91407 changed the serialization format which leads to ICEs for nightly users such as #91663 and linked issues. The issue can be solved by running `cargo clean`. But bumping the metadata version should lead to the cached files being discarded, avoiding the issue entirely.
In Rust, nesting method calls with both require `&mut` access to `self`
produces a borrow-check error:
error[E0499]: cannot borrow `*self` as mutable more than once at a time
--> src/lib.rs:7:14
|
7 | self.foo(self.bar());
| ---------^^^^^^^^^^-
| | | |
| | | second mutable borrow occurs here
| | first borrow later used by call
| first mutable borrow occurs here
That's because Rust has a left-to-right evaluation order, and the method
receiver is passed first. Thus, the argument to the method cannot then
mutate `self`.
There's an easy solution to this error: just extract a local variable
for the inner argument:
let tmp = self.bar();
self.foo(tmp);
However, the error doesn't give any suggestion of how to solve the
problem. As a result, new users may assume that it's impossible to
express their code correctly and get stuck.
This commit adds a (non-structured) suggestion to extract a local
variable for the inner argument to solve the error. The suggestion uses
heuristics that eliminate most false positives, though there are a few
false negatives (cases where the suggestion should be emitted but is
not). Those other cases can be implemented in a future change.
Fix ICE on format string of macro with secondary-label
This generalizes the fix#86104 to also correctly skip `Span::from_inner` for the `secondary_label` of a format macro parsing error as well.
We can alternatively skip the `span_label` diagnostic call for the secondary label as well, since that label probably only makes sense when the _proper_ span is computed.
Fixes#91556
code-cov: generate dead functions with private/default linkage
As discovered in #85461, the MSVC linker treats weak symbols slightly
differently than unix-y linkers do. This causes link.exe to fail with
LNK1227 "conflicting weak extern definition" where as other targets are
able to link successfully.
This changes the dead functions from being generated as weak/hidden to
private/default which, as the LLVM reference says:
> Global values with “private” linkage are only directly accessible by
objects in the current module. In particular, linking code into a module
with a private global value may cause the private to be renamed as
necessary to avoid collisions. Because the symbol is private to the
module, all references can be updated. This doesn’t show up in any
symbol table in the object file.
This fixes the conflicting weak symbols but doesn't address the reason
*why* we have conflicting symbols for these dead functions. The test
cases added in this commit contain a minimal repro of the fundamental
issue which is that the logic used to decide what dead code functions
should be codegen'd in the current CGU doesn't take into account that
functions can be duplicated across multiple CGUs (for instance, in the
case of `#[inline(always)]` functions).
Fixing that is likely to be a more complex change (see
https://github.com/rust-lang/rust/issues/85461#issuecomment-985005805).
Fixes#85461
```
error[E0759]: `self` has an anonymous lifetime `'_` but it needs to satisfy a `'static` lifetime requirement
--> $DIR/issue-72312.rs:10:24
|
LL | pub async fn start(&self) {
| ^^^^^ this data with an anonymous lifetime `'_`...
...
LL | require_static(async move {
| -------------- ...is required to live as long as `'static` here...
LL | &self;
| ----- ...and is captured here
|
note: `'static` lifetime requirement introduced by this trait bound
--> $DIR/issue-72312.rs:2:22
|
LL | fn require_static<T: 'static>(val: T) -> T {
| ^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0759`.
```
Fix#72312.
