MIR lowering for `if let` expressions is now more complicated now that
`if let` exists in HIR. This PR adds a scope for the variables bound in
an `if let` expression and then uses an approach similar to how we
handle loops to ensure that we reliably drop the correct variables.
Emit specific warning to clarify that `#[no_mangle]` should not be applied on foreign statics or functions
Foreign statics and foreign functions should not have `#[no_mangle]` applied, as it does nothing to the name and has some extra hidden behavior that is normally unwanted. There was an existing warning for this, but it says the attribute is only allowed on "statics or functions", which to the user can be confusing.
This PR adds a specific version of the unused `#[no_mangle]` warning that explains that the target is a *foreign* static or function and that they do not need the attribute.
Fixes#78989
rustc_target: `TyAndLayout::field` should never error.
This refactor (making `TyAndLayout::field` return `TyAndLayout` without any `Result` around it) is based on a simple observation, regarding `TyAndLayout::field`:
If `cx.layout_of(ty)` succeeds (for some `cx` and `ty`), then `.field(cx, i)` on the resulting `TyAndLayout` should *always* succeed in computing `cx.layout_of(field_ty)` (where `field_ty` is the type of the `i`th field of `ty`).
The reason for this is that no matter which field is chosen, `cx.layout_of(field_ty)` *will have already been computed*, as part of computing `cx.layout_of(ty)`, as we cannot determine the layout of *any* type without considering the layouts of *all* of its fields.
And so it should be fine to turn any errors into ICEs, since they likely indicate a `cx` mismatch, or some other edge case that is due to a compiler bug (as opposed to ever being an user-facing error).
<hr/>
Each commit should probably be reviewed separately, though note that there's some `where` clauses (in `rustc_target::abi::call::*`) that change in most commits.
cc `@nagisa` `@oli-obk`
Improve detection of generics on lang items
Adds detection for the required generics for all lang items. Many lang items require an exact or minimum amount of generic arguments and if they don't exist, the compiler will ICE. This does not add any additional validation about bounds on generics or any other lang item restrictions.
Fixes one of the ICEs in #87573
cc `@FabianWolff`
Improve liveness analysis for generators
Liveness analysis for generators assumes that execution always continues
normally after a yield point, not accounting for the fact that generator
could be dropped before completion.
If generators captures any variables by reference, those variables could
be used within a generator, or when the generator completes, but also
after each yield point in the case the generator is dropped.
Account for the case when generator is dropped after yielding, but
before running to the completion. This effectively considers all
variables captured by reference to be used after a yield point.
Fixes#84292.
Liveness analysis for generators assumes that execution always continues
normally after a yield point, not accounting for the fact that generator
could be dropped before completion.
If generators captures any variables by reference, those variables could
be used within a generator, or when the generator completes, but also
after each yield point in the case the generator is dropped.
Account for the case when generator is dropped after yielding, but
before running to the completion. This effectively considers all
variables captured by reference to be used after a yield point.
Remove `Session.used_attrs` and move logic to `CheckAttrVisitor`
Instead of updating global state to mark attributes as used,
we now explicitly emit a warning when an attribute is used in
an unsupported position. As a side effect, we are to emit more
detailed warning messages (instead of just a generic "unused" message).
`Session.check_name` is removed, since its only purpose was to mark
the attribute as used. All of the callers are modified to use
`Attribute.has_name`
Additionally, `AttributeType::AssumedUsed` is removed - an 'assumed
used' attribute is implemented by simply not performing any checks
in `CheckAttrVisitor` for a particular attribute.
We no longer emit unused attribute warnings for the `#[rustc_dummy]`
attribute - it's an internal attribute used for tests, so it doesn't
mark sense to treat it as 'unused'.
With this commit, a large source of global untracked state is removed.
Warn about unreachable code following an expression with an uninhabited type
This pull request fixes#85071. The issue is that liveness analysis currently is "smarter" than reachability analysis when it comes to detecting uninhabited types: Unreachable code is detected during type checking, where full type information is not yet available. Therefore, the check for type inhabitedness is quite crude:
fc81ad22c4/compiler/rustc_typeck/src/check/expr.rs (L202-L205)
i.e. it only checks for `!`, but not other, non-trivially uninhabited types, such as empty enums, structs containing an uninhabited type, etc. By contrast, liveness analysis, which runs after type checking, can benefit from the more sophisticated `tcx.is_ty_uninhabited_from()`:
fc81ad22c4/compiler/rustc_passes/src/liveness.rs (L981)fc81ad22c4/compiler/rustc_passes/src/liveness.rs (L996)
This can lead to confusing warnings when a variable is reported as unused, but the use of the variable is not reported as unreachable. For instance:
```rust
enum Foo {}
fn f() -> Foo {todo!()}
fn main() {
let x = f();
let _ = x;
}
```
currently leads to
```
warning: unused variable: `x`
--> t1.rs:5:9
|
5 | let x = f();
| ^ help: if this is intentional, prefix it with an underscore: `_x`
|
= note: `#[warn(unused_variables)]` on by default
warning: 1 warning emitted
```
which is confusing, because `x` _appears_ to be used in line 6. With my changes, I get:
```
warning: unreachable expression
--> t1.rs:6:13
|
5 | let x = f();
| --- any code following this expression is unreachable
6 | let _ = x;
| ^ unreachable expression
|
= note: `#[warn(unreachable_code)]` on by default
note: this expression has type `Foo`, which is uninhabited
--> t1.rs:5:13
|
5 | let x = f();
| ^^^
warning: unused variable: `x`
--> t1.rs:5:9
|
5 | let x = f();
| ^ help: if this is intentional, prefix it with an underscore: `_x`
|
= note: `#[warn(unused_variables)]` on by default
warning: 2 warnings emitted
```
My implementation is slightly inelegant because unreachable code warnings can now be issued in two different places (during type checking and during liveness analysis), but I think it is the solution with the least amount of unnecessary code duplication, given that the new warning integrates nicely with liveness analysis, where unreachable code is already implicitly detected for the purpose of finding unused variables.
Instead of updating global state to mark attributes as used,
we now explicitly emit a warning when an attribute is used in
an unsupported position. As a side effect, we are to emit more
detailed warning messages (instead of just a generic "unused" message).
`Session.check_name` is removed, since its only purpose was to mark
the attribute as used. All of the callers are modified to use
`Attribute.has_name`
Additionally, `AttributeType::AssumedUsed` is removed - an 'assumed
used' attribute is implemented by simply not performing any checks
in `CheckAttrVisitor` for a particular attribute.
We no longer emit unused attribute warnings for the `#[rustc_dummy]`
attribute - it's an internal attribute used for tests, so it doesn't
mark sense to treat it as 'unused'.
With this commit, a large source of global untracked state is removed.
Add future-incompat lint for `doc(primitive)`
## What is `doc(primitive)`?
`doc(primitive)` is an attribute recognized by rustdoc which adds documentation for the built-in primitive types, such as `usize` and `()`. It has been stable since Rust 1.0.
## Why change anything?
`doc(primitive)` is useless for anyone outside the standard library. Since rustdoc provides no way to combine the documentation on two different primitive items, you can only replace the docs, and since the standard library already provides extensive documentation there is no reason to do so.
While fixing rustdoc's handling of primitive items (https://github.com/rust-lang/rust/pull/87073) I discovered that even rustdoc's existing handling of primitive items was broken if you had more than two crates using it (it would pick randomly between them). That meant both:
- Keeping rustdoc's existing treatment was nigh-impossible, because it was random.
- doc(primitive) was even more useless than it would otherwise be.
The only use-case for this outside the standard library is for no-std libraries which want to link to primitives (https://github.com/rust-lang/rust/issues/73423) which is being fixed in https://github.com/rust-lang/rust/pull/87073.
https://github.com/rust-lang/rust/pull/87073 makes various breaking changes to `doc(primitive)` (breaking in the sense that they change the semantics, not in that they cause code to fail to compile). It's not possible to avoid these and still fix rustdoc's issues.
## What can we do about it?
As shown by the crater run (https://github.com/rust-lang/rust/pull/87050#issuecomment-886166706), no one is actually using doc(primitive), there wasn't a single true regression in the whole run. We can either:
1. Feature gate it completely, breaking anyone who crater missed. They can easily fix the breakage just by removing the attribute.
2. add it to the `INVALID_DOC_ATTRIBUTES` future-incompat lint, and at the same time make it a no-op unless you add a feature gate. That would mean rustdoc has to look at the features of dependent crates, because it needs to know where primitives are defined in order to link to them.
3. add it to `INVALID_DOC_ATTRIBUTES`, but still use it to determine where primitives come from
4. do nothing; the behavior will silently change in https://github.com/rust-lang/rust/pull/87073.
My preference is for 2, but I would also be happy with 1 or 3. I don't think we should silently change the behavior.
This PR currently implements 3.
Move naked function ABI check to its own lint
This check was previously categorized under the lint named
`UNSUPPORTED_NAKED_FUNCTIONS`. That lint is future incompatible and will
be turned into an error in a future release. However, as defined in the
Constrained Naked Functions RFC, this check should only be a warning.
This is because it is possible for a naked function to be implemented in
such a way that it does not break even the undefined ABI. For example, a
`jmp` to a `const`.
Therefore, this patch defines a new lint named
`UNDEFINED_NAKED_FUNCTION_ABI` which contains just this single check.
Unlike `UNSUPPORTED_NAKED_FUNCTIONS`, `UNDEFINED_NAKED_FUNCTION_ABI`
will not be converted to an error in the future.
rust-lang/rfcs#2774rust-lang/rfcs#2972
In most calling conventions, accessing function parameters may require
stack access. However, naked functions have no assembly prelude to set
up stack access. This is why naked functions may only contain a single
`asm!()` block. All parameter access is done inside the `asm!()` block,
so we cannot validate the liveness of the input parameters. Therefore,
we should disable the lint for naked functions.
rust-lang/rfcs#2774rust-lang/rfcs#2972
This check was previously categorized under the lint named
`UNSUPPORTED_NAKED_FUNCTIONS`. That lint is future incompatible and will
be turned into an error in a future release. However, as defined in the
Constrained Naked Functions RFC, this check should only be a warning.
This is because it is possible for a naked function to be implemented in
such a way that it does not break even the undefined ABI. For example, a
`jmp` to a `const`.
Therefore, this patch defines a new lint named
`UNDEFINED_NAKED_FUNCTION_ABI` which contains just this single check.
Unlike `UNSUPPORTED_NAKED_FUNCTIONS`, `UNDEFINED_NAKED_FUNCTION_ABI`
will not be converted to an error in the future.
rust-lang/rfcs#2774rust-lang/rfcs#2972
rustc: Replace `HirId`s with `LocalDefId`s in `AccessLevels` tables
and passes using those tables - primarily privacy checking, stability checking and dead code checking.
All these passes work with definitions rather than with arbitrary HIR nodes.
r? `@cjgillot`
cc `@lambinoo` (#87487)
rfc3052 followup: Remove authors field from Cargo manifests
Since RFC 3052 soft deprecated the authors field, hiding it from
crates.io, docs.rs, and making Cargo not add it by default, and it is
not generally up to date/useful information for contributors, we may as well
remove it from crates in this repo.
Since RFC 3052 soft deprecated the authors field anyway, hiding it from
crates.io, docs.rs, and making Cargo not add it by default, and it is
not generally up to date/useful information, we should remove it from
crates in this repo.
Checking that function is const if marked with rustc_const_unstable
Fixes#69630
This one is still missing tests to check the behavior but I checked by hand and it seemed to work.
I would not mind some direction for writing those unit tests!
Use diagnostic items instead of lang items for rfc2229 migrations
This PR removes the `Send`, `UnwindSafe` and `RefUnwindSafe` lang items introduced in https://github.com/rust-lang/rust/pull/84730, and uses diagnostic items instead to check for `Send`, `UnwindSafe` and `RefUnwindSafe` traits for RFC2229 migrations.
r? ```@nikomatsakis```
remove trailing newline
fix: test with attribute but missing const
Update compiler/rustc_passes/src/stability.rs
Co-authored-by: Léo Lanteri Thauvin <leseulartichaut@gmail.com>
Add test for extern functions
fix: using span_help instead of span_suggestion
add test for some ABIs + fmt fix
Update compiler/rustc_passes/src/stability.rs
Co-authored-by: Léo Lanteri Thauvin <leseulartichaut@gmail.com>
Refractor and add test for `impl const`
Add test to make sure no output + cleanup condition
-----------------------------
remove stdcall test, failing CI test
C abi is already tested in this, so it is not that useful to test another one.
The tested code is blind to which specific ABI for now, as long as it's not an intrinsic one
deny using default function in impl const Trait
Fixes#79450.
I don't know if my implementation is correct:
- The check is in `rustc_passes::check_const`, should I put it somewhere else instead?
- Is my approach (to checking the impl) optimal? It works for the current tests, but it might have some issues or there might be a better way of doing this.
Fix ICE when `main` is declared in an `extern` block
Changes in #84401 to implement `imported_main` changed how the crate entry point is found, and a declared `main` in an `extern` block was detected erroneously. This was causing the ICE described in #86110.
This PR adds a check for this case and emits an error instead. Previously a `main` declaration in an `extern` block was not detected as an entry point at all, so emitting an error shouldn't break anything that worked previously. In 1.52.1 stable this is demonstrated, with a `` `main` function not found`` error.
Fixes#86110
Remove unused dependencies from compiler crates
Various compiler crates have dependencies that they don't appear to use. I used some scripting to detect such dependencies, filtered them based on some manual review, and removed those that do indeed appear to be entirely unused.
Remove unused feature gates
The first commit removes a usage of a feature gate, but I don't expect it to be controversial as the feature gate was only used to workaround a limitation of rust in the past. (closures never being `Clone`)
The second commit uses `#[allow_internal_unstable]` to avoid leaking the `trusted_step` feature gate usage from inside the index newtype macro. It didn't work for the `min_specialization` feature gate though.
The third commit removes (almost) all feature gates from the compiler that weren't used anyway.
Report an error if a lang item has the wrong number of generic arguments
This pull request fixes#83893. The issue is that the lang item code currently checks whether the lang item has the correct item kind (e.g. a `#[lang="add"]` has to be a trait), but not whether the item has the correct number of generic arguments.
This can lead to an "index out of bounds" ICE when the compiler tries to create more substitutions than there are suitable types available (if the lang item was declared with too many generic arguments).
For instance, here is a reduced ("reduced" in the sense that it does not trigger additional errors) version of the example given in #83893:
```rust
#![feature(lang_items,no_core)]
#![no_core]
#![crate_type="lib"]
#[lang = "sized"]
trait MySized {}
#[lang = "add"]
trait MyAdd<'a, T> {}
fn ice() {
let r = 5;
let a = 6;
r + a
}
```
On current nightly, this immediately causes an ICE without any warnings or errors emitted. With the changes in this PR, however, I get no ICE and two errors:
```
error[E0718]: `add` language item must be applied to a trait with 1 generic argument
--> pr-ex.rs:8:1
|
8 | #[lang = "add"]
| ^^^^^^^^^^^^^^^
9 | trait MyAdd<'a, T> {}
| ------- this trait has 2 generic arguments, not 1
error[E0369]: cannot add `{integer}` to `{integer}`
--> pr-ex.rs:14:7
|
14 | r + a
| - ^ - {integer}
| |
| {integer}
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0369, E0718.
For more information about an error, try `rustc --explain E0369`.
```
Remove CrateNum parameter for queries that only work on local crate
The pervasive `CrateNum` parameter is a remnant of the multi-crate rustc idea.
Using `()` as query key in those cases avoids having to worry about the validity of the query key.
Remove support for floating-point constants in asm!
Floating-point constants aren't very useful anyways and this simplifies
the code since the type check can now be done in typeck.
cc `@rust-lang/wg-inline-asm`
r? `@nagisa`
Reachable statics have reachable initializers
Static initializer can read other statics. Initializers are evaluated at
compile time, and so their content could become inlined into another
crate. Ensure that initializers of reachable statics are also reachable.
Previously, when an item incorrectly considered to be unreachable was
reached from another crate an attempt would be made to codegen it. The
attempt could fail with an ICE (in the case MIR wasn't available to do
so) in some circumstances the attempt could also succeed resulting in
a local codegen of non-local items, including static ones.
Fixes#84455.
Fix `--remap-path-prefix` not correctly remapping `rust-src` component paths and unify handling of path mapping with virtualized paths
This PR fixes#73167 ("Binaries end up containing path to the rust-src component despite `--remap-path-prefix`") by preventing real local filesystem paths from reaching compilation output if the path is supposed to be remapped.
`RealFileName::Named` introduced in #72767 is now renamed as `LocalPath`, because this variant wraps a (most likely) valid local filesystem path.
`RealFileName::Devirtualized` is renamed as `Remapped` to be used for remapped path from a real path via `--remap-path-prefix` argument, as well as real path inferred from a virtualized (during compiler bootstrapping) `/rustc/...` path. The `local_path` field is now an `Option<PathBuf>`, as it will be set to `None` before serialisation, so it never reaches any build output. Attempting to serialise a non-`None` `local_path` will cause an assertion faliure.
When a path is remapped, a `RealFileName::Remapped` variant is created. The original path is preserved in `local_path` field and the remapped path is saved in `virtual_name` field. Previously, the `local_path` is directly modified which goes against its purpose of "suitable for reading from the file system on the local host".
`rustc_span::SourceFile`'s fields `unmapped_path` (introduced by #44940) and `name_was_remapped` (introduced by #41508 when `--remap-path-prefix` feature originally added) are removed, as these two pieces of information can be inferred from the `name` field: if it's anything other than a `FileName::Real(_)`, or if it is a `FileName::Real(RealFileName::LocalPath(_))`, then clearly `name_was_remapped` would've been false and `unmapped_path` would've been `None`. If it is a `FileName::Real(RealFileName::Remapped{local_path, virtual_name})`, then `name_was_remapped` would've been true and `unmapped_path` would've been `Some(local_path)`.
cc `@eddyb` who implemented `/rustc/...` path devirtualisation
Fix typo in report_unsed_assign
The function was called `report_unsed_assign`, which I assume is a typo, considering the rest of the file.
This replaces `report_unsed_assign` with `report_unused_assign`.
Static initializer can read other statics. Initializers are evaluated at
compile time, and so their content could become inlined into another
crate. Ensure that initializers of reachable statics are also reachable.
Previously, when an item incorrectly considered to be unreachable was
reached from another crate an attempt would be made to codegen it. The
attempt could fail with an ICE (in the case MIR wasn't available to do
so) in some circumstances the attempt could also succeed resulting in
a local codegen of non-local items, including static ones.
further split up const_fn feature flag
This continues the work on splitting up `const_fn` into separate feature flags:
* `const_fn_trait_bound` for `const fn` with trait bounds
* `const_fn_unsize` for unsizing coercions in `const fn` (looks like only `dyn` unsizing is still guarded here)
I don't know if there are even any things left that `const_fn` guards... at least libcore and liballoc do not need it any more.
`@oli-obk` are you currently able to do reviews?
Match against attribute name when validating attributes
Extract attribute name once and match it against symbols that are being
validated, instead of using `Session::check_name` for each symbol
individually.
Assume that all validated attributes are used, instead of marking them
as such, since the attribute check should be exhaustive.
Extract attribute name once and match it against symbols that are being
validated, instead of using `Session::check_name` for each symbol
individually.
Assume that all validated attributes are used, instead of marking them
as such, since the attribute check should be exhaustive.
Use AnonConst for asm! constants
This replaces the old system which used explicit promotion. See #83169 for more background.
The syntax for `const` operands is still the same as before: `const <expr>`.
Fixes#83169
Because the implementation is heavily based on inline consts, we suffer from the same issues:
- We lose the ability to use expressions derived from generics. See the deleted tests in `src/test/ui/asm/const.rs`.
- We are hitting the same ICEs as inline consts, for example #78174. It is unlikely that we will be able to stabilize this before inline consts are stabilized.
Rename `#[doc(spotlight)]` to `#[doc(notable_trait)]`
Fixes#80936.
"spotlight" is not a very specific or self-explaining name.
Additionally, the dialog that it triggers is called "Notable traits".
So, "notable trait" is a better name.
* Rename `#[doc(spotlight)]` to `#[doc(notable_trait)]`
* Rename `#![feature(doc_spotlight)]` to `#![feature(doc_notable_trait)]`
* Update documentation
* Improve documentation
r? `@Manishearth`
GenericParam does not need to be a HIR owner.
The special case is not required.
Universal impl traits design to regular generic parameters, and their content is owned by the enclosing item.
Existential (and opaque) impl traits generate their own enclosing item, and are collected through it.
implement `feature(const_generics_defaults)`
Implements const generics defaults `struct Example<const N: usize=3>`, as well as a query for getting the default of a given const-parameter's def id. There are some remaining FIXME's but they were specified as not blocking for merging this PR. This also puts the defaults behind the unstable feature gate `#![feature(const_generics_defaults)]`.
~~This currently creates a field which is always false on `GenericParamDefKind` for future use when
consts are permitted to have defaults. I'm not sure if this is exactly what is best for adding default parameters, but I mimicked the style of type defaults, so hopefully this is ok.~~
r? `@lcnr`
Only enable assert_dep_graph when query-dep-graph is enabled.
This is a debugging option. The only effect should be on rustc tests.
r? ``@michaelwoerister``
Replace closures_captures and upvar_capture with closure_min_captures
Removed all uses of closures_captures and upvar_capture and refactored code to work with closure_min_captures. This also involved removing functions that were no longer needed like the bridge.
Closes https://github.com/rust-lang/project-rfc-2229/issues/18
r? `@nikomatsakis`
rustdoc: allow list syntax for #[doc(alias)] attributes
Fixes https://github.com/rust-lang/rust/issues/81205.
It now allows to have:
```rust
#[doc(alias = "x")]
// and:
#[doc(alias("y", "z"))]
```
cc ``@jplatte``
r? ``@jyn514``
make changes to liveness to use closure_min_captures
use different span
borrow check uses new structures
rename to CapturedPlace
stop using upvar_capture in regionck
remove the bridge
cleanup from rebase + remove the upvar_capture reference from mutability_errors.rs
remove line from livenes test
make our unused var checking more consistent
update tests
adding more warnings to the tests
move is_ancestor_or_same_capture to rustc_middle/ty
update names to reflect the closures
add FIXME
check that all captures are immutable borrows before returning
add surrounding if statement like the original
move var out of the loop and rename
Co-authored-by: Logan Mosier <logmosier@gmail.com>
Co-authored-by: Roxane Fruytier <roxane.fruytier@hotmail.com>
StructField -> FieldDef ("field definition")
Field -> ExprField ("expression field", not "field expression")
FieldPat -> PatField ("pattern field", not "field pattern")
Also rename visiting and other methods working on them.
"spotlight" is not a very specific or self-explaining name.
Additionally, the dialog that it triggers is called "Notable traits".
So, "notable trait" is a better name.
* Rename `#[doc(spotlight)]` to `#[doc(notable_trait)]`
* Rename `#![feature(doc_spotlight)]` to `#![feature(doc_notable_trait)]`
* Update documentation
* Improve documentation
Find more invalid doc attributes
- Lint on `#[doc(123)]`, `#[doc("hello")]`, etc.
- Lint every attribute; e.g., will now report two warnings for `#[doc(foo, bar)]`
- Add hyphen to "crate level"
- Display paths like `#[doc(foo::bar)]` correctly instead of as an empty string
This change makes it easier to follow the control flow.
I also moved the end-of-line comments attached to some symbols to before
the symbol listing. This allows rustfmt to format the code; otherwise no
formatting occurs (see rust-lang/rustfmt#4750).
Cleanup rustdoc warnings
## Clean up error reporting for deprecated passes
Using `error!` here goes all the way back to the original commit, https://github.com/rust-lang/rust/pull/8540. I don't see any reason to use logging; rustdoc should use diagnostics wherever possible. See https://github.com/rust-lang/rust/pull/81932#issuecomment-785291244 for further context.
- Use spans for deprecated attributes
- Use a proper diagnostic for unknown passes, instead of error logging
- Add tests for unknown passes
- Improve some wording in diagnostics
## Report that `doc(plugins)` doesn't work using diagnostics instead of `eprintln!`
This also adds a test for the output.
This was added in https://github.com/rust-lang/rust/pull/52194. I don't see any particular reason not to use diagnostics here, I think it was just missed in https://github.com/rust-lang/rust/pull/50541.
Warn on `#![doc(test(...))]` on items other than the crate root and use future incompatible lint
Part of #82672.
This PR does multiple things:
* Create a new `INVALID_DOC_ATTRIBUTE` lint which is also "future incompatible", allowing us to use it as a warning for the moment until it turns (eventually) into a hard error.
* Use this link when `#![doc(test(...))]` isn't used at the crate level.
* Make #82702 use this new lint as well.
r? ``@jyn514``
Inherit `#[stable(..)]` annotations in enum variants and fields from its item
Lint changes for #65515. The stdlib will have to be updated once this lands in beta and that version is promoted in master.
Add #[rustc_legacy_const_generics]
This is the first step towards removing `#[rustc_args_required_const]`: a new attribute is added which rewrites function calls of the form `func(a, b, c)` to `func::<{b}>(a, c)`. This allows previously stabilized functions in `stdarch` which use `rustc_args_required_const` to use const generics instead.
This new attribute is not intended to ever be stabilized, it is only intended for use in `stdarch` as a replacement for `#[rustc_args_required_const]`.
```rust
#[rustc_legacy_const_generics(1)]
pub fn foo<const Y: usize>(x: usize, z: usize) -> [usize; 3] {
[x, Y, z]
}
fn main() {
assert_eq!(foo(0 + 0, 1 + 1, 2 + 2), [0, 2, 4]);
assert_eq!(foo::<{1 + 1}>(0 + 0, 2 + 2), [0, 2, 4]);
}
```
r? `@oli-obk`
Consider auto derefs before warning about write only fields
Changes from #81473 extended the dead code lint with an ability to detect
fields that are written to but never read from. The implementation skips
over fields on the left hand side of an assignment, without marking them
as live.
A field access might involve an automatic dereference and de-facto read
the field. Conservatively mark expressions with deref adjustments as
live to avoid generating false positive warnings.
Closes#81626.
Implement -Z hir-stats for nested foreign items
An attempt to compute HIR stats for crates with nested foreign items results in an ICE.
```rust
fn main() {
extern "C" { fn f(); }
}
```
```
thread 'rustc' panicked at 'visit_nested_xxx must be manually implemented in this visitor'
```
Provide required implementation of visitor method.
ast: Keep expansion status for out-of-line module items
I.e. whether a module `mod foo;` is already loaded from a file or not.
This is a pre-requisite to correctly treating inner attributes on such modules (https://github.com/rust-lang/rust/issues/81661).
With this change AST structures for `mod` items diverge even more for AST structure for the crate root, which previously used `ast::Mod`.
Therefore this PR removes `ast::Mod` from `ast::Crate` in the first commit, these two things are sufficiently different from each other, at least at syntactic level.
Customization points for visiting a "`mod` item or crate root" were also removed from AST visitors (`fn visit_mod`).
`ast::Mod` itself was refactored away in the second commit in favor of `ItemKind::Mod(Unsafe, ModKind)`.
Changes from 81473 extended the dead code lint with an ability to detect
fields that are written to but never read from. The implementation skips
over fields on the left hand side of an assignment, without marking them
as live.
A field access might involve an automatic dereference and de-facto read
the field. Conservatively mark expressions with deref adjustments as
live to avoid generating false positive warnings.
Print -Ztime-passes (and misc stats/logs) on stderr, not stdout.
I've tried not to change anything that looked similar to `rustc --print`, where people might use automation, and/or any "bulk" prints, such as dumping an entire Graphviz (`dot`) graph on stdout.
The reason I want `-Ztime-passes` to be on stderr like debug logging is I can get a complete (and correctly interleaved) view just by looking at stderr, which is merely a convenience when running `rustc`/Cargo directly, but even more important when it's nested in a build script, as Cargo will split the build script output into stdout (named `output`) and `stderr`.
Crate root is sufficiently different from `mod` items, at least at syntactic level.
Also remove customization point for "`mod` item or crate root" from AST visitors.
An attempt to compute HIR stats for crates with nested foreign items results in an ICE.
```
fn main() {
extern "C" { fn f(); }
}
```
```
thread 'rustc' panicked at 'visit_nested_xxx must be manually implemented in this visitor'
```
Provide required implementation of visitor method.
