And likewise for the `Const::val` method.
Because its type is called `ConstKind`. Also `val` is a confusing name
because `ConstKind` is an enum with seven variants, one of which is
called `Value`. Also, this gives consistency with `TyS` and `PredicateS`
which have `kind` fields.
The commit also renames a few `Const` variables from `val` to `c`, to
avoid confusion with the `ConstKind::Value` variant.
Remove unnecessary `to_string` and `String::new`
73fa217bc1 changed the type of the `suggestion` argument to `impl ToString`. This patch removes unnecessary `to_string` and `String::new`.
cc: `````@davidtwco`````
This is done so that we can check the noisiness of this lint in a Crater
run. Note that when I built the compiler, I actually encountered lots of
places where this lint will trigger and fail compilation, so I had to
also set `RUSTFLAGS_NOT_BOOSTRAP` to `-A let_underscore_drop` when
compiling to prevent that.
Introduce allow-by-default lints for checking whether diagnostics are
written in `SessionDiagnostic`/`AddSubdiagnostic` impls and whether
diagnostics are translatable. These lints can be denied for modules once
they are fully migrated to impls and translation.
Signed-off-by: David Wood <david.wood@huawei.com>
This commit makes type folding more like the way chalk does it.
Currently, `TypeFoldable` has `fold_with` and `super_fold_with` methods.
- `fold_with` is the standard entry point, and defaults to calling
`super_fold_with`.
- `super_fold_with` does the actual work of traversing a type.
- For a few types of interest (`Ty`, `Region`, etc.) `fold_with` instead
calls into a `TypeFolder`, which can then call back into
`super_fold_with`.
With the new approach, `TypeFoldable` has `fold_with` and
`TypeSuperFoldable` has `super_fold_with`.
- `fold_with` is still the standard entry point, *and* it does the
actual work of traversing a type, for all types except types of
interest.
- `super_fold_with` is only implemented for the types of interest.
Benefits of the new model.
- I find it easier to understand. The distinction between types of
interest and other types is clearer, and `super_fold_with` doesn't
exist for most types.
- With the current model is easy to get confused and implement a
`super_fold_with` method that should be left defaulted. (Some of the
precursor commits fixed such cases.)
- With the current model it's easy to call `super_fold_with` within
`TypeFolder` impls where `fold_with` should be called. The new
approach makes this mistake impossible, and this commit fixes a number
of such cases.
- It's potentially faster, because it avoids the `fold_with` ->
`super_fold_with` call in all cases except types of interest. A lot of
the time the compile would inline those away, but not necessarily
always.
Remove migrate borrowck mode
Closes#58781Closes#43234
# Stabilization proposal
This PR proposes the stabilization of `#![feature(nll)]` and the removal of `-Z borrowck`. Current borrow checking behavior of item bodies is currently done by first infering regions *lexically* and reporting any errors during HIR type checking. If there *are* any errors, then MIR borrowck (NLL) never occurs. If there *aren't* any errors, then MIR borrowck happens and any errors there would be reported. This PR removes the lexical region check of item bodies entirely and only uses MIR borrowck. Because MIR borrowck could never *not* be run for a compiled program, this should not break any programs. It does, however, change diagnostics significantly and allows a slightly larger set of programs to compile.
Tracking issue: #43234
RFC: https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md
Version: 1.63 (2022-06-30 => beta, 2022-08-11 => stable).
## Motivation
Over time, the Rust borrow checker has become "smarter" and thus allowed more programs to compile. There have been three different implementations: AST borrowck, MIR borrowck, and polonius (well, in progress). Additionally, there is the "lexical region resolver", which (roughly) solves the constraints generated through HIR typeck. It is not a full borrow checker, but does emit some errors.
The AST borrowck was the original implementation of the borrow checker and was part of the initially stabilized Rust 1.0. In mid 2017, work began to implement the current MIR borrow checker and that effort ompleted by the end of 2017, for the most part. During 2018, efforts were made to migrate away from the AST borrow checker to the MIR borrow checker - eventually culminating into "migrate" mode - where HIR typeck with lexical region resolving following by MIR borrow checking - being active by default in the 2018 edition.
In early 2019, migrate mode was turned on by default in the 2015 edition as well, but with MIR borrowck errors emitted as warnings. By late 2019, these warnings were upgraded to full errors. This was followed by the complete removal of the AST borrow checker.
In the period since, various errors emitted by the MIR borrow checker have been improved to the point that they are mostly the same or better than those emitted by the lexical region resolver.
While there do remain some degradations in errors (tracked under the [NLL-diagnostics tag](https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3ANLL-diagnostics), those are sufficiently small and rare enough that increased flexibility of MIR borrow check-only is now a worthwhile tradeoff.
## What is stabilized
As said previously, this does not fundamentally change the landscape of accepted programs. However, there are a [few](https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3ANLL-fixed-by-NLL) cases where programs can compile under `feature(nll)`, but not otherwise.
There are two notable patterns that are "fixed" by this stabilization. First, the `scoped_threads` feature, which is a continutation of a pre-1.0 API, can sometimes emit a [weird lifetime error](https://github.com/rust-lang/rust/issues/95527) without NLL. Second, actually seen in the standard library. In the `Extend` impl for `HashMap`, there is an implied bound of `K: 'a` that is available with NLL on but not without - this is utilized in the impl.
As mentioned before, there are a large number of diagnostic differences. Most of them are better, but some are worse. None are serious or happen often enough to need to block this PR. The biggest change is the loss of error code for a number of lifetime errors in favor of more general "lifetime may not live long enough" error. While this may *seem* bad, the former error codes were just attempts to somewhat-arbitrarily bin together lifetime errors of the same type; however, on paper, they end up being roughly the same with roughly the same kinds of solutions.
## What isn't stabilized
This PR does not completely remove the lexical region resolver. In the future, it may be possible to remove that (while still keeping HIR typeck) or to remove it together with HIR typeck.
## Tests
Many test outputs get updated by this PR. However, there are number of tests specifically geared towards NLL under `src/test/ui/nll`
## History
* On 2017-07-14, [tracking issue opened](https://github.com/rust-lang/rust/issues/43234)
* On 2017-07-20, [initial empty MIR pass added](https://github.com/rust-lang/rust/pull/43271)
* On 2017-08-29, [RFC opened](https://github.com/rust-lang/rfcs/pull/2094)
* On 2017-11-16, [Integrate MIR type-checker with NLL](https://github.com/rust-lang/rust/pull/45825)
* On 2017-12-20, [NLL feature complete](https://github.com/rust-lang/rust/pull/46862)
* On 2018-07-07, [Don't run AST borrowck on mir mode](https://github.com/rust-lang/rust/pull/52083)
* On 2018-07-27, [Add migrate mode](https://github.com/rust-lang/rust/pull/52681)
* On 2019-04-22, [Enable migrate mode on 2015 edition](https://github.com/rust-lang/rust/pull/59114)
* On 2019-08-26, [Don't downgrade errors on 2015 edition](https://github.com/rust-lang/rust/pull/64221)
* On 2019-08-27, [Remove AST borrowck](https://github.com/rust-lang/rust/pull/64790)
Using diagnostic items avoids having to update the paths if the guard
types ever get moved around for some reason. Additionally, it also greatly
simplifies the `is_sync_lock` check.
If the type has a trivial Drop implementation, then it is probably irrelevant
that the type was dropped immediately, since nothing important
happens on drop. Hence, we can bail out early instead of doing some
expensive checks.
This commit uses `span_suggestion_verbose` to add what specific code
changes can be done as suggested by the lint--in this case, either binding
the expression to an unused variable or using `std::mem::drop` to drop
the value explicitly.
These lints are very noisy and are allow-by-default in clippy anyways.
Hence, setting them to allow-by-default here makes more sense than
warning constantly on these cases.
Similar to `let_underscore_drop`, this lint checks for statements similar
to `let _ = foo`, where `foo` is a lock guard. These types of let
statements are especially problematic because the lock gets released
immediately, instead of at the end of the scope. This behavior is almost
always the wrong thing.
This lint checks for statements similar to `let _ = foo`, where `foo` is
a type that implements `Drop`. These types of let statements cause the
expression in them to be dropped immediately, instead of at the end of
the scope. Such behavior can be surprizing, especially if you are
relying on the value to be dropped at the end of the scope. Instead, the
binding should be an underscore prefixed name (like `_unused`) or the
value should explicitly be passed to `std::mem::drop()` if the value
really should be dropped immediately.
Make weird name lints trigger behind cfg_attr
The weird name lints (`unknown_lints`, `renamed_and_removed_lints`), the lints that lint the linting, were previously not firing for lint level declarations behind `cfg_attr`, as they were only running before expansion.
Now, this will give a `unknown_lints` warning:
```Rust
#[cfg_attr(all(), allow(this_lint_does_not_exist))]
fn foo() {}
```
Lint level declarations behind a `cfg_attr` whose condition is not applying are still ignored. So this still won't give a warning:
```Rust
#[cfg_attr(any(), allow(this_lint_does_not_exist))]
fn foo() {}
```
Furthermore, this PR also makes the weird name lints respect level delcarations for *them* that were hidden by `cfg_attr`, making them consistent to other lints. So this will now not issue a warning:
```Rust
#[cfg_attr(all(), allow(unknown_lints))]
mod foo {
#[allow(does_not_exist)]
fn foo() {
}
}
```
Fixes#97094
Previously, we were emitting weird name lints (for renamed or unknown lints)
before expansion, most importantly before cfg expansion.
This meant that the weird name lints would not fire
for lint attributes hidden inside cfg_attr. The same applied
for lint level specifications of those lints.
By moving the lints for the lint names to the post-expansion
phase, these issues are resolved.
Add a query for checking whether a function is an intrinsic.
work towards #93145
This will reduce churn when we add more ways to declare intrinsics
r? `@scottmcm`
don't encode only locally used attrs
Part of https://github.com/rust-lang/compiler-team/issues/505.
We now filter builtin attributes before encoding them in the crate metadata in case they should only be used in the local crate. To prevent accidental misuse `get_attrs` now requires the caller to state which attribute they are interested in. For places where that isn't trivially possible, I've added a method `fn get_attrs_unchecked` which I intend to remove in a followup PR.
After this pull request landed, we can then slowly move all attributes to only be used in the local crate while being certain that we don't accidentally try to access them from extern crates.
cc https://github.com/rust-lang/rust/pull/94963#issuecomment-1082924289
Implement a lint to warn about unused macro rules
This implements a new lint to warn about unused macro rules (arms/matchers), similar to the `unused_macros` lint added by #41907 that warns about entire macros.
```rust
macro_rules! unused_empty {
(hello) => { println!("Hello, world!") };
() => { println!("empty") }; //~ ERROR: 1st rule of macro `unused_empty` is never used
}
fn main() {
unused_empty!(hello);
}
```
Builds upon #96149 and #96156.
Fixes#73576
Do not lint on explicit outlives requirements from external macros.
The current implementation of the list rightfully skipped where predicates from external macros.
However, if the where predicate came from the current macro but the bounds were from an external macro, the lint still fired.
Closes https://github.com/rust-lang/rust/issues/96640
Support tool lints with the `#[expect]` attribute (RFC 2383)
This PR fixes the ICE https://github.com/rust-lang/rust/issues/94953 by making the assert for converted expectation IDs conditional.
Additionally, it moves the lint expectation check into a separate query to support rustdoc and other tools. On the way, I've also added some tests to ensure that the attribute works for Clippy and rustdoc lints.
The number of changes comes from the long test file. This may look like a monster PR, this may smell like a monster PR and this may be a monster PR, but it's a harmless monster. 🦕
---
Closes: https://github.com/rust-lang/rust/issues/94953
cc: https://github.com/rust-lang/rust/issues/85549
r? `@wesleywiser`
cc: `@rust-lang/rustdoc`
Track if a where bound comes from a impl Trait desugar
With https://github.com/rust-lang/rust/pull/93803 `impl Trait` function arguments get desugared to hidden where bounds. However, Clippy needs to know if a bound was originally a `impl Trait` or an actual bound. This adds a field to the `WhereBoundPredicate` struct to keep track of this information during AST->HIR lowering.
r? `@cjgillot`
cc `@estebank` (as the reviewer of #93803)
With #93803 `impl Trait` function arguments get desugared to hidden
where bounds. However, Clippy needs to know if a bound was originally a
impl Trait or an actual bound. This adds a field to the
`WhereBoundPredicate` struct to keep track of this information during
HIR lowering.
Remove mutable_borrow_reservation_conflict lint and allow the code pattern
This was the only breaking issue with the NLL stabilization PR. Lang team decided to go ahead and allow this.
r? `@nikomatsakis`
Closes#59159Closes#56254
Only crate root def-ids don't have a parent, and in majority of cases the argument of `DefIdTree::parent` cannot be a crate root.
So we now panic by default in `parent` and introduce a new non-panicing function `opt_parent` for cases where the argument can be a crate root.
Same applies to `local_parent`/`opt_local_parent`.
Change `span_suggestion` (and variants) to take `impl ToString` rather
than `String` for the suggested code, as this simplifies the
requirements on the diagnostic derive.
Signed-off-by: David Wood <david.wood@huawei.com>
Remove `--extern-location` and all associated code
`--extern-location` was an experiment to investigate the best way to
generate useful diagnostics for unused dependency warnings by enabling a
build system to identify the corresponding build config.
While I did successfully use this, I've since been convinced the
alternative `--json unused-externs` mechanism is the way to go, and
there's no point in having two mechanisms with basically the same
functionality.
This effectively reverts https://github.com/rust-lang/rust/pull/72603
`--extern-location` was an experiment to investigate the best way to
generate useful diagnostics for unused dependency warnings by enabling a
build system to identify the corresponding build config.
While I did successfully use this, I've since been convinced the
alternative `--json unused-externs` mechanism is the way to go, and
there's no point in having two mechanisms with basically the same
functionality.
This effectively reverts https://github.com/rust-lang/rust/pull/72603
Let CTFE to handle partially uninitialized unions without marking the entire value as uninitialized.
follow up to #94411
To fix https://github.com/rust-lang/rust/issues/69488 and by extension fix https://github.com/rust-lang/rust/issues/94371, we should stop treating types like `MaybeUninit<usize>` as something that the `Scalar` type in the interpreter engine can represent. So we add a new field to `abi::Primitive` that records whether the primitive is nested in a union
cc `@RalfJung`
r? `@ghost`
This commit updates the signatures of all diagnostic functions to accept
types that can be converted into a `DiagnosticMessage`. This enables
existing diagnostic calls to continue to work as before and Fluent
identifiers to be provided. The `SessionDiagnostic` derive just
generates normal diagnostic calls, so these APIs had to be modified to
accept Fluent identifiers.
In addition, loading of the "fallback" Fluent bundle, which contains the
built-in English messages, has been implemented.
Each diagnostic now has "arguments" which correspond to variables in the
Fluent messages (necessary to render a Fluent message) but no API for
adding arguments has been added yet. Therefore, diagnostics (that do not
require interpolation) can be converted to use Fluent identifiers and
will be output as before.
`MultiSpan` contains labels, which are more complicated with the
introduction of diagnostic translation and will use types from
`rustc_errors` - however, `rustc_errors` depends on `rustc_span` so
`rustc_span` cannot use types like `DiagnosticMessage` without
dependency cycles. Introduce a new `rustc_error_messages` crate that can
contain `DiagnosticMessage` and `MultiSpan`.
Signed-off-by: David Wood <david.wood@huawei.com>
There are a few places were we have to construct it, though, and a few
places that are more invasive to change. To do this, we create a
constructor with a long obvious name.
fix typos
Rework of #94603 which got closed as I was trying to unmerge and repush. This is a subset of changes from the original pr as I sed'd whatever typos I remembered from the original PR
thanks to `@cuishuang` for the original PR
Improve `expect` impl and handle `#[expect(unfulfilled_lint_expectations)]` (RFC 2383)
This PR updates unstable `ExpectationIds` in stashed diagnostics and adds some asserts to ensure that the stored expectations are really empty in the end. Additionally, it handles the `#[expect(unfulfilled_lint_expectations)]` case.
According to the [Errors and lints docs](https://rustc-dev-guide.rust-lang.org/diagnostics.html#diagnostic-levels) the `error` level should only be used _"when the compiler detects a problem that makes it unable to compile the program"_. As this isn't the case with `#[expect(unfulfilled_lint_expectations)]` I decided to only create a warning. To avoid adding a new lint only for this case, I simply emit a `unfulfilled_lint_expectations` diagnostic with an additional note.
---
r? `@wesleywiser` I'm requesting a review from you since you reviewed the previous PR https://github.com/rust-lang/rust/pull/87835. You are welcome to reassign it if you're busy 🙃
rfc: [RFC-2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html)
tracking issue: https://github.com/rust-lang/rust/issues/85549
cc: `@flip1995` In case you're also interested in this :)
Improve `AdtDef` interning.
This commit makes `AdtDef` use `Interned`. Much of the commit is tedious
changes to introduce getter functions. The interesting changes are in
`compiler/rustc_middle/src/ty/adt.rs`.
r? `@fee1-dead`
This commit makes `AdtDef` use `Interned`. Much the commit is tedious
changes to introduce getter functions. The interesting changes are in
`compiler/rustc_middle/src/ty/adt.rs`.
This also affects the `non_exhaustive_omitted_patterns` and
`must_not_suspend` lints as they are not stable. This also changes the
diagnostic level to pull from `unknown_lints` instead of always being
allow or deny.
This change causes unstable lints to be ignored if the `unknown_lints`
lint is allowed. To achieve this, it also changes lints to apply as soon
as they are processed. Previously, lints in the same set were processed
as a batch and then all simultaneously applied.
Implementation of https://github.com/rust-lang/compiler-team/issues/469
Generalize `get_nullable_type` to allow types where null is all-ones.
Generalize get_nullable_type to accept types that have an all-ones bit
pattern as their sentry "null" value.
This will allow [`OwnedFd`], [`BorrowedFd`], [`OwnedSocket`], and
[`BorrowedSocket`] to be marked with
`#[rustc_nonnull_optimization_guaranteed]`, which will allow
`Option<OwnedFd>`, `Option<BorrowedFd>`, `Option<OwnedSocket>`, and
`Option<BorrowedSocket>` to be used in FFI declarations, as described
in the [I/O safety RFC].
For example, it will allow a function like `open` on Unix and `WSASocketW`
on Windows to be declared using `Option<OwnedFd>` and `Option<OwnedSocket>`
return types, respectively.
The actual change to add `#[rustc_nonnull_optimization_guaranteed]`
to the abovementioned types will be a separate PR, as it'll depend on
having this patch in the stage0 compiler.
Also, update the diagnostics to mention that "niche optimizations" are
used in libstd as well as libcore, as `rustc_layout_scalar_valid_range_start`
and `rustc_layout_scalar_valid_range_end` are already in use in libstd.
[`OwnedFd`]: c9dc44be24/library/std/src/os/fd/owned.rs (L49)
[`BorrowedFd`]: c9dc44be24/library/std/src/os/fd/owned.rs (L29)
[`OwnedSocket`]: c9dc44be24/library/std/src/os/windows/io/socket.rs (L51)
[`BorrowedSocket`]: c9dc44be24/library/std/src/os/windows/io/socket.rs (L29)
[I/O safety RFC]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md#ownedfd-and-borrowedfdfd-1
Emit `unused_attributes` if a level attr only has a reason
Fixes a comment from `compiler/rustc_lint/src/levels.rs`. Lint level attributes that only contain a reason will also trigger the `unused_attribute` lint. The lint now also checks for the `expect` lint level.
That's it, have a great rest of the day for everyone reasoning this 🙃
cc: #55112
`Layout` is another type that is sometimes interned, sometimes not, and
we always use references to refer to it so we can't take any advantage
of the uniqueness properties for hashing or equality checks.
This commit renames `Layout` as `LayoutS`, and then introduces a new
`Layout` that is a newtype around an `Interned<LayoutS>`. It also
interns more layouts than before. Previously layouts within layouts
(via the `variants` field) were never interned, but now they are. Hence
the lifetime on the new `Layout` type.
Unlike other interned types, these ones are in `rustc_target` instead of
`rustc_middle`. This reflects the existing structure of the code, which
does layout-specific stuff in `rustc_target` while `TyAndLayout` is
generic over the `Ty`, allowing the type-specific stuff to occur in
`rustc_middle`.
The commit also adds a `HashStable` impl for `Interned`, which was
needed. It hashes the contents, unlike the `Hash` impl which hashes the
pointer.
Generalize get_nullable_type to accept types that have an all-ones bit
pattern as their sentry "null" value.
This will allow [`OwnedFd`], [`BorrowedFd`], [`OwnedSocket`], and
[`BorrowedSocket`] to be marked with
`#[rustc_nonnull_optimization_guaranteed]`, which will allow
`Option<OwnedFd>`, `Option<BorrowedFd>`, `Option<OwnedSocket>`, and
`Option<BorrowedSocket>` to be used in FFI declarations, as described
in the [I/O safety RFC].
For example, it will allow a function like `open` on Unix and `WSASocketW`
on Windows to be declared using `Option<OwnedFd>` and `Option<OwnedSocket>`
return types, respectively.
The actual change to add `#[rustc_nonnull_optimization_guaranteed]`
to the abovementioned types will be a separate PR, as it'll depend on
having this patch in the stage0 compiler.
Also, update the diagnostics to mention that "niche optimizations" are
used in libstd as well as libcore, as `rustc_layout_scalar_valid_range_start`
and `rustc_layout_scalar_valid_range_end` are already in use in libstd.
[`OwnedFd`]: c9dc44be24/library/std/src/os/fd/owned.rs (L49)
[`BorrowedFd`]: c9dc44be24/library/std/src/os/fd/owned.rs (L29)
[`OwnedSocket`]: c9dc44be24/library/std/src/os/windows/io/socket.rs (L51)
[`BorrowedSocket`]: c9dc44be24/library/std/src/os/windows/io/socket.rs (L29)
[I/O safety RFC]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md#ownedfd-and-borrowedfdfd-1
Implementation of the `expect` attribute (RFC 2383)
This is an implementation of the `expect` attribute as described in [RFC-2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html). The attribute allows the suppression of lint message by expecting them. Unfulfilled lint expectations (meaning no expected lint was caught) will emit the `unfulfilled_lint_expectations` lint at the `expect` attribute.
### Example
#### input
```rs
// required feature flag
#![feature(lint_reasons)]
#[expect(unused_mut)] // Will warn about an unfulfilled expectation
#[expect(unused_variables)] // Will be fulfilled by x
fn main() {
let x = 0;
}
```
#### output
```txt
warning: this lint expectation is unfulfilled
--> $DIR/trigger_lint.rs:3:1
|
LL | #[expect(unused_mut)] // Will warn about an unfulfilled expectation
| ^^^^^^^^^^
|
= note: `#[warn(unfulfilled_lint_expectations)]` on by default
```
### Implementation
This implementation introduces `Expect` as a new lint level for diagnostics, which have been expected. All lint expectations marked via the `expect` attribute are collected in the [`LintLevelsBuilder`] and assigned an ID that is stored in the new lint level. The `LintLevelsBuilder` stores all found expectations and the data needed to emit the `unfulfilled_lint_expectations` in the [`LintLevelsMap`] which is the result of the [`lint_levels()`] query.
The [`rustc_errors::HandlerInner`] is the central error handler in rustc and handles the emission of all diagnostics. Lint message with the level `Expect` are suppressed during this emission, while the expectation ID is stored in a set which marks them as fulfilled. The last step is then so simply check if all expectations collected by the [`LintLevelsBuilder`] in the [`LintLevelsMap`] have been marked as fulfilled in the [`rustc_errors::HandlerInner`]. Otherwise, a new lint message will be emitted.
The implementation of the `LintExpectationId` required some special handling to make it stable between sessions. Lints can be emitted during [`EarlyLintPass`]es. At this stage, it's not possible to create a stable identifier. The level instead stores an unstable identifier, which is later converted to a stable `LintExpectationId`.
### Followup TO-DOs
All open TO-DOs have been marked with `FIXME` comments in the code. This is the combined list of them:
* [ ] The current implementation doesn't cover cases where the `unfulfilled_lint_expectations` lint is actually expected by another `expect` attribute.
* This should be easily possible, but I wanted to get some feedback before putting more work into this.
* This could also be done in a new PR to not add to much more code to this one
* [ ] Update unstable documentation to reflect this change.
* [ ] Update unstable expectation ids in [`HandlerInner::stashed_diagnostics`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/struct.HandlerInner.html#structfield.stashed_diagnostics)
### Open questions
I also have a few open questions where I would like to get feedback on:
1. The RFC discussion included a suggestion to change the `expect` attribute to something else. (Initiated by `@Ixrec` [here](https://github.com/rust-lang/rfcs/pull/2383#issuecomment-378424091), suggestion from `@scottmcm` to use `#[should_lint(...)]` [here](https://github.com/rust-lang/rfcs/pull/2383#issuecomment-378648877)). No real conclusion was drawn on that point from my understanding. Is this still open for discussion, or was this discarded with the merge of the RFC?
2. How should the expect attribute deal with the new `force-warn` lint level?
---
This approach was inspired by a discussion with `@LeSeulArtichaut.`
RFC tracking issue: #54503
Mentoring/Implementation issue: #85549
[`LintLevelsBuilder`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/levels/struct.LintLevelsBuilder.html
[`LintLevelsMap`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/lint/struct.LintLevelMap.html
[`lint_levels()`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/context/struct.TyCtxt.html#method.lint_levels
[`rustc_errors::HandlerInner`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/struct.HandlerInner.html
[`EarlyLintPass`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/trait.EarlyLintPass.html
* Add UI tests with macros for the `expect` attribute (RFC-2383)
* Addressed review comments - mostly UI test updates (RFC-2383)
* Documented lint level attribute on macro not working bug (RFC-2383)
See `rust#87391`
Document that pre-expansion lint passes are softly deprecated
The pre-expansion lint pass has been softly deprecated since https://github.com/rust-lang/rust/pull/69838. Every once in a while I see someone mention it as a possibility, only get the feedback that it's deprecated. This PR officially documents that the method is soft deprecated to have a single point of truth for it.
That's it. Have a great rest of the day 🙃
---
* See [rust#69838](https://github.com/rust-lang/rust/pull/69838)
* See [rust-clippy#5518](https://github.com/rust-lang/rust-clippy/pull/5518)
Initiate the inner usage of `let_chains`
The intention here is create a strong and robust foundation for a possible future stabilization so please, do not let the lack of any external tool support prevent the merge of this PR. Besides, `let_chains` is useful by itself.
cc #53667
Rollup of 4 pull requests
Successful merges:
- #93850 (Don't ICE when an extern static is too big for the current architecture)
- #94154 (Wire up unstable rustc --check-cfg to rustdoc)
- #94353 (Fix debug_assert in unused lint pass)
- #94366 (Add missing item to release notes)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
This fixes a debug assertion in the unused lint pass. As a side effect,
this also improves the span generated for tuples in the
`unused_must_use` lint.
rustc_errors: let `DiagnosticBuilder::emit` return a "guarantee of emission".
That is, `DiagnosticBuilder` is now generic over the return type of `.emit()`, so we'll now have:
* `DiagnosticBuilder<ErrorReported>` for error (incl. fatal/bug) diagnostics
* can only be created via a `const L: Level`-generic constructor, that limits allowed variants via a `where` clause, so not even `rustc_errors` can accidentally bypass this limitation
* asserts `diagnostic.is_error()` on emission, just in case the construction restriction was bypassed (e.g. by replacing the whole `Diagnostic` inside `DiagnosticBuilder`)
* `.emit()` returns `ErrorReported`, as a "proof" token that `.emit()` was called
(though note that this isn't a real guarantee until after completing the work on
#69426)
* `DiagnosticBuilder<()>` for everything else (warnings, notes, etc.)
* can also be obtained from other `DiagnosticBuilder`s by calling `.forget_guarantee()`
This PR is a companion to other ongoing work, namely:
* #69426
and it's ongoing implementation:
#93222
the API changes in this PR are needed to get statically-checked "only errors produce `ErrorReported` from `.emit()`", but doesn't itself provide any really strong guarantees without those other `ErrorReported` changes
* #93244
would make the choices of API changes (esp. naming) in this PR fit better overall
In order to be able to let `.emit()` return anything trustable, several changes had to be made:
* `Diagnostic`'s `level` field is now private to `rustc_errors`, to disallow arbitrary "downgrade"s from "some kind of error" to "warning" (or anything else that doesn't cause compilation to fail)
* it's still possible to replace the whole `Diagnostic` inside the `DiagnosticBuilder`, sadly, that's harder to fix, but it's unlikely enough that we can paper over it with asserts on `.emit()`
* `.cancel()` now consumes `DiagnosticBuilder`, preventing `.emit()` calls on a cancelled diagnostic
* it's also now done internally, through `DiagnosticBuilder`-private state, instead of having a `Level::Cancelled` variant that can be read (or worse, written) by the user
* this removes a hazard of calling `.cancel()` on an error then continuing to attach details to it, and even expect to be able to `.emit()` it
* warnings were switched to *only* `can_emit_warnings` on emission (instead of pre-cancelling early)
* `struct_dummy` was removed (as it relied on a pre-`Cancelled` `Diagnostic`)
* since `.emit()` doesn't consume the `DiagnosticBuilder` <sub>(I tried and gave up, it's much more work than this PR)</sub>,
we have to make `.emit()` idempotent wrt the guarantees it returns
* thankfully, `err.emit(); err.emit();` can return `ErrorReported` both times, as the second `.emit()` call has no side-effects *only* because the first one did do the appropriate emission
* `&mut Diagnostic` is now used in a lot of function signatures, which used to take `&mut DiagnosticBuilder` (in the interest of not having to make those functions generic)
* the APIs were already mostly identical, allowing for low-effort porting to this new setup
* only some of the suggestion methods needed some rework, to have the extra `DiagnosticBuilder` functionality on the `Diagnostic` methods themselves (that change is also present in #93259)
* `.emit()`/`.cancel()` aren't available, but IMO calling them from an "error decorator/annotator" function isn't a good practice, and can lead to strange behavior (from the caller's perspective)
* `.downgrade_to_delayed_bug()` was added, letting you convert any `.is_error()` diagnostic into a `delay_span_bug` one (which works because in both cases the guarantees available are the same)
This PR should ideally be reviewed commit-by-commit, since there is a lot of fallout in each.
r? `@estebank` cc `@Manishearth` `@nikomatsakis` `@mark-i-m`
Improve `--check-cfg` implementation
This pull-request is a mix of improvements regarding the `--check-cfg` implementation:
- Simpler internal representation (usage of `Option` instead of separate bool)
- Add --check-cfg to the unstable book (based on the RFC)
- Improved diagnostics:
* List possible values when the value is unexpected
* Suggest if possible a name or value that is similar
- Add more tests (well known names, mix of combinations, ...)
r? ```@petrochenkov```
Move ty::print methods to Drop-based scope guards
Primary goal is reducing codegen of the TLS access for each closure, which shaves ~3 seconds of bootstrap time over rustc as a whole.
Specifically, rename the `Const` struct as `ConstS` and re-introduce `Const` as
this:
```
pub struct Const<'tcx>(&'tcx Interned<ConstS>);
```
This now matches `Ty` and `Predicate` more closely, including using
pointer-based `eq` and `hash`.
Notable changes:
- `mk_const` now takes a `ConstS`.
- `Const` was copy, despite being 48 bytes. Now `ConstS` is not, so need a
we need separate arena for it, because we can't use the `Dropless` one any
more.
- Many `&'tcx Const<'tcx>`/`&Const<'tcx>` to `Const<'tcx>` changes
- Many `ct.ty` to `ct.ty()` and `ct.val` to `ct.val()` changes.
- Lots of tedious sigil fiddling.
Specifically, change `Region` from this:
```
pub type Region<'tcx> = &'tcx RegionKind;
```
to this:
```
pub struct Region<'tcx>(&'tcx Interned<RegionKind>);
```
This now matches `Ty` and `Predicate` more closely.
Things to note
- Regions have always been interned, but we haven't been using pointer-based
`Eq` and `Hash`. This is now happening.
- I chose to impl `Deref` for `Region` because it makes pattern matching a lot
nicer, and `Region` can be viewed as just a smart wrapper for `RegionKind`.
- Various methods are moved from `RegionKind` to `Region`.
- There is a lot of tedious sigil changes.
- A couple of types like `HighlightBuilder`, `RegionHighlightMode` now have a
`'tcx` lifetime because they hold a `Ty<'tcx>`, so they can call `mk_region`.
- A couple of test outputs change slightly, I'm not sure why, but the new
outputs are a little better.
Specifically, change `Ty` from this:
```
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
```
to this
```
pub struct Ty<'tcx>(Interned<'tcx, TyS<'tcx>>);
```
There are two benefits to this.
- It's now a first class type, so we can define methods on it. This
means we can move a lot of methods away from `TyS`, leaving `TyS` as a
barely-used type, which is appropriate given that it's not meant to
be used directly.
- The uniqueness requirement is now explicit, via the `Interned` type.
E.g. the pointer-based `Eq` and `Hash` comes from `Interned`, rather
than via `TyS`, which wasn't obvious at all.
Much of this commit is boring churn. The interesting changes are in
these files:
- compiler/rustc_middle/src/arena.rs
- compiler/rustc_middle/src/mir/visit.rs
- compiler/rustc_middle/src/ty/context.rs
- compiler/rustc_middle/src/ty/mod.rs
Specifically:
- Most mentions of `TyS` are removed. It's very much a dumb struct now;
`Ty` has all the smarts.
- `TyS` now has `crate` visibility instead of `pub`.
- `TyS::make_for_test` is removed in favour of the static `BOOL_TY`,
which just works better with the new structure.
- The `Eq`/`Ord`/`Hash` impls are removed from `TyS`. `Interned`s impls
of `Eq`/`Hash` now suffice. `Ord` is now partly on `Interned`
(pointer-based, for the `Equal` case) and partly on `TyS`
(contents-based, for the other cases).
- There are many tedious sigil adjustments, i.e. adding or removing `*`
or `&`. They seem to be unavoidable.
Lazy type-alias-impl-trait
Previously opaque types were processed by
1. replacing all mentions of them with inference variables
2. memorizing these inference variables in a side-table
3. at the end of typeck, resolve the inference variables in the side table and use the resolved type as the hidden type of the opaque type
This worked okayish for `impl Trait` in return position, but required lots of roundabout type inference hacks and processing.
This PR instead stops this process of replacing opaque types with inference variables, and just keeps the opaque types around.
Whenever an opaque type `O` is compared with another type `T`, we make the comparison succeed and record `T` as the hidden type. If `O` is compared to `U` while there is a recorded hidden type for it, we grab the recorded type (`T`) and compare that against `U`. This makes implementing
* https://github.com/rust-lang/rfcs/pull/2515
much simpler (previous attempts on the inference based scheme were very prone to ICEs and general misbehaviour that was not explainable except by random implementation defined oddities).
r? `@nikomatsakis`
fixes#93411fixes#88236
Fix invalid special casing of the unreachable! macro
This pull-request fix an invalid special casing of the `unreachable!` macro in the same way the `panic!` macro was solved, by adding two new internal only macros `unreachable_2015` and `unreachable_2021` edition dependent and turn `unreachable!` into a built-in macro that do dispatching. This logic is stolen from the `panic!` macro.
~~This pull-request also adds an internal feature `format_args_capture_non_literal` that allows capturing arguments from formatted string that expanded from macros. The original RFC #2795 mentioned this as a future possibility. This feature is [required](https://github.com/rust-lang/rust/issues/92137#issuecomment-1018630522) because of concatenation that needs to be done inside the macro:~~
```rust
$crate::concat!("internal error: entered unreachable code: ", $fmt)
```
**In summary** the new behavior for the `unreachable!` macro with this pr is:
Edition 2021:
```rust
let x = 5;
unreachable!("x is {x}");
```
```
internal error: entered unreachable code: x is 5
```
Edition <= 2018:
```rust
let x = 5;
unreachable!("x is {x}");
```
```
internal error: entered unreachable code: x is {x}
```
Also note that the change in this PR are **insta-stable** and **breaking changes** but this a considered as being a [bug](https://github.com/rust-lang/rust/issues/92137#issuecomment-998441613).
If someone could start a perf run and then a crater run this would be appreciated.
Fixes https://github.com/rust-lang/rust/issues/92137
by using an opaque type obligation to bubble up comparisons between opaque types and other types
Also uses proper obligation causes so that the body id works, because out of some reason nll uses body ids for logic instead of just diagnostics.
Add note suggesting that predicate may be satisfied, but is not `const`
Not sure if we should be printing this in addition to, or perhaps _instead_ of the help message:
```
help: the trait `~const Add` is not implemented for `NonConstAdd`
```
Also added `ParamEnv::is_const` and `PolyTraitPredicate::is_const_if_const` and, in a separate commit, used those in other places instead of `== hir::Constness::Const`, etc.
r? ````@fee1-dead````
Add links to the reference and rust by example for asm! docs and lints
These were previously removed in #91728 due to broken links.
cc ``@ehuss`` since this updates the rust-by-example submodule
Clarify the `usage-of-qualified-ty` error message.
I found this message confusing when I encountered it. This commit makes
it clearer that you have to import the unqualified type yourself.
r? `@lcnr`
Use consistent function parameter order for early context construction and early linting
Rename some functions to make it clear that they do not necessarily work on the whole crate
Reject unsupported naked functions
Transition unsupported naked functions future incompatibility lint into an error:
* Naked functions must contain a single inline assembly block. Introduced as future incompatibility lint in 1.50 #79653. Change into an error fixes a soundness issue described in #32489.
* Naked functions must not use any forms of inline attribute. Introduced as future incompatibility lint in 1.56 #87652.
Closes#32490.
Closes#32489.
r? ```@Amanieu``` ```@npmccallum``` ```@joshtriplett```
Transition unsupported naked functions future incompatibility lint into
an error:
* Naked functions must contain a single inline assembly block.
Introduced as future incompatibility lint in 1.50 #79653.
Change into an error fixes a soundness issue described in #32489.
* Naked functions must not use any forms of inline attribute.
Introduced as future incompatibility lint in 1.56 #87652.
Change lint message to be stronger for &T -> &mut T transmute
The old message implied that it's only UB if you use the reference to mutate, which (as far as I know) is not true. As in, the following program has UB, and a &T -> &mut T transmute is effectively an `unreachable_unchecked`.
```rust
fn main() {
#[allow(mutable_transmutes)]
unsafe {
let _ = std::mem::transmute::<&i32, &mut i32>(&0);
}
}
```
In the future, it might be a good idea to use the edition system to make this a hard error, since I don't think it is *ever* defined behaviour? Unless we rule that `&UnsafeCell<i32> -> &mut i32` is fine. (That, and you always could just use `.get()`, so you're not losing anything)
Mak DefId to AccessLevel map in resolve for export
hir_id to accesslevel in resolve and applied in privacy
using local def id
removing tracing probes
making function not recursive and adding comments
Move most of Exported/Public res to rustc_resolve
moving public/export res to resolve
fix missing stability attributes in core, std and alloc
move code to access_levels.rs
return for some kinds instead of going through them
Export correctness, macro changes, comments
add comment for import binding
add comment for import binding
renmae to access level visitor, remove comments, move fn as closure, remove new_key
fmt
fix rebase
fix rebase
fmt
fmt
fix: move macro def to rustc_resolve
fix: reachable AccessLevel for enum variants
fmt
fix: missing stability attributes for other architectures
allow unreachable pub in rustfmt
fix: missing impl access level + renaming export to reexport
Missing impl access level was found thanks to a test in clippy
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`
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.
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`
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`
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).
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.
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.
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.
TraitKind -> Trait
TyAliasKind -> TyAlias
ImplKind -> Impl
FnKind -> Fn
All `*Kind`s in AST are supposed to be enums.
Tuple structs are converted to braced structs for the types above, and fields are reordered in syntactic order.
Also, mutable AST visitor now correctly visit spans in defaultness, unsafety, impl polarity and constness.
Don't mark for loop iter expression as desugared
We typically don't mark spans of lowered things as desugared. This helps Clippy rightly discern when code is (not) from expansion. This was discovered by ``@flip1995`` at https://github.com/rust-lang/rust-clippy/pull/7789#issuecomment-939289501.
Remove unwrap_or! macro
Removes `unwrap_or!` macro and replaces it with `match`.
It's kinda cleanup, as rustc_ast not the best place for this macro and this is used only in 2 places anyway.
Fix extra `non_snake_case` warning for shorthand field bindings
Fixes#89469. The problem is the innermost `if` condition here:
d14731cb3c/compiler/rustc_lint/src/nonstandard_style.rs (L435-L452)
This code runs for every `PatKind::Binding`, so if a struct has multiple fields, say A and B, and both are bound in a pattern using shorthands, the call to `self.check_snake_case()` will indeed be skipped in the `check_pat()` call for `A`; but when `check_pat()` is called for `B`, the loop will still iterate over `A`, and `field.ident (= A) != ident (= B)` will be true. I have fixed this by only looking at non-shorthand bindings, and only the binding that `check_pat()` was actually called for.
Remove some feature gates
The first commit removes various feature gates that are unused. The second commit replaces some `Fn` implementations with `Iterator` implementations, which is much cleaner IMO. The third commit replaces an unboxed_closures feature gate with min_specialization. For some reason the unboxed_closures feature gate suppresses the min_specialization feature gate from triggering on an `TrustedStep` impl. The last comment just turns a regular comment into a doc comment as drive by cleanup. I can move it to a separate PR if preferred.
Make diangostic item naming consistent
Right now there is about a 50/50 split of naming diagnostic items as `vec_type` vs `Vec`. So it is hard to guess a diagnostic item name with confidence. I know it's not great to change these retroactively, but I think it will be much easier to maintain consistency after consistency is established.
Make *const (), *mut () okay for FFI
Pointer-to-() is used occasionally in the standard library to mean "pointer to none-of-your-business". Examples:
- `RawWakerVTable::new` https://doc.rust-lang.org/1.51.0/std/task/struct.RawWakerVTable.html#method.new
- `<*const T>::to_raw_parts` https://doc.rust-lang.org/nightly/std/primitive.pointer.html#method.to_raw_parts
I believe it's useful for the same purpose in FFI signatures, even while `()` itself is not FFI safe. The following should be allowed:
```rust
extern "C" {
fn demo(pc: *const (), pm: *mut ());
}
```
Prior to this PR, those pointers were not considered okay for an extern signature.
```console
warning: `extern` block uses type `()`, which is not FFI-safe
--> src/main.rs:2:17
|
2 | fn demo(pc: *const (), pm: *mut ());
| ^^^^^^^^^ not FFI-safe
|
= note: `#[warn(improper_ctypes)]` on by default
= help: consider using a struct instead
= note: tuples have unspecified layout
warning: `extern` block uses type `()`, which is not FFI-safe
--> src/main.rs:2:32
|
2 | fn demo(pc: *const (), pm: *mut ());
| ^^^^^^^ not FFI-safe
|
= help: consider using a struct instead
= note: tuples have unspecified layout
```
Implement `#[must_not_suspend]`
implements #83310
Some notes on the impl:
1. The code that searches for the attribute on the ADT is basically copied from the `must_use` lint. It's not shared, as the logic did diverge
2. The RFC does specify that the attribute can be placed on fn's (and fn-like objects), like `must_use`. I think this is a direct copy from the `must_use` reference definition. This implementation does NOT support this, as I felt that ADT's (+ `impl Trait` + `dyn Trait`) cover the usecase's people actually want on the RFC, and adding an imp for the fn call case would be significantly harder. The `must_use` impl can do a single check at fn call stmt time, but `must_not_suspend` would need to answer the question: "for some value X with type T, find any fn call that COULD have produced this value". That would require significant changes to `generator_interior.rs`, and I would need mentorship on that. `@eholk` and I are discussing it.
3. `@estebank` do you know a way I can make the user-provided `reason` note pop out? right now it seems quite hidden
Also, I am not sure if we should run perf on this
r? `@nikomatsakis`
This also adjusts the lint docs generation to accept (and ignore) an allow
attribute, rather than expecting the documentation to be immediately followed by
the lint name.
Gather module items after lowering.
This avoids having a non-local analysis inside lowering.
By implementing `hir_module_items` using a visitor, we make sure that iterations and visitors are consistent.
Fix ICE in `improper_ctypes_definitions` lint with all-ZST transparent types
Fixes#87496. There is also another function in the same file that looks fishy, but I haven't been able to produce an ICE there, and in any case, it's not related to #87496:
fd853c00e2/compiler/rustc_lint/src/types.rs (L720-L734)
r? ```@JohnTitor```
Const drop
The changes are pretty primitive at this point. But at least it works. ^-^
Problems with the current change that I can think of now:
- [x] `~const Drop` shouldn't change anything in the non-const world.
- [x] types that do not have drop glues shouldn't fail to satisfy `~const Drop` in const contexts. `struct S { a: u8, b: u16 }` This might not fail for `needs_non_const_drop`, but it will fail in `rustc_trait_selection`.
- [x] The current change accepts types that have `const Drop` impls but have non-const `Drop` glue.
Fixes#88424.
Significant Changes:
- `~const Drop` is no longer treated as a normal trait bound. In non-const contexts, this bound has no effect, but in const contexts, this restricts the input type and all of its transitive fields to either a) have a `const Drop` impl or b) can be trivially dropped (i.e. no drop glue)
- `T: ~const Drop` will not be linted like `T: Drop`.
- Instead of recursing and iterating through the type in `rustc_mir::transform::check_consts`, we use the trait system to special case `~const Drop`. See [`rustc_trait_selection::...::candidate_assembly#assemble_const_drop_candidates`](https://github.com/fee1-dead/rust/blob/const-drop/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs#L817) and others.
Changes not related to `const Drop`ping and/or changes that are insignificant:
- `Node.constness_for_typeck` no longer returns `hir::Constness::Const` for type aliases in traits. This was previously used to hack how we determine default bound constness for items. But because we now use an explicit opt-in, it is no longer needed.
- Removed `is_const_impl_raw` query. We have `impl_constness`, and the only existing use of that query uses `HirId`, which means we can just operate it with hir.
- `ty::Destructor` now has a field `constness`, which represents the constness of the destructor.
r? `@oli-obk`
Avoid invoking the hir_crate query to traverse the HIR
Walking the HIR tree is done using the `hir_crate` query. However, this is unnecessary, since `hir_owner(CRATE_DEF_ID)` provides the same information. Since depending on `hir_crate` forces dependents to always be executed, this leads to unnecessary work.
By splitting HIR and attributes visits, we can avoid an edge to `hir_crate` when trying to visit the HIR tree.
Provide `layout_of` automatically (given tcx + param_env + error handling).
After #88337, there's no longer any uses of `LayoutOf` within `rustc_target` itself, so I realized I could move the trait to `rustc_middle::ty::layout` and redesign it a bit.
This is similar to #88338 (and supersedes it), but at no ergonomic loss, since there's no funky `C: LayoutOf<Ty = Ty>` -> `Ty: TyAbiInterface<C>` generic `impl` chain, and each `LayoutOf` still corresponds to one `impl` (of `LayoutOfHelpers`) for the specific context.
After this PR, this is what's needed to get `trait LayoutOf` (with the `layout_of` method) implemented on some context type:
* `TyCtxt`, via `HasTyCtxt`
* `ParamEnv`, via `HasParamEnv`
* a way to transform `LayoutError`s into the desired error type
* an error type of `!` can be paired with having `cx.layout_of(...)` return `TyAndLayout` *without* `Result<...>` around it, such as used by codegen
* this is done through a new `LayoutOfHelpers` trait (and so is specifying the type of `cx.layout_of(...)`)
When going through this path (and not bypassing it with a manual `impl` of `LayoutOf`), the end result is that only the error case can be customized, the query itself and the success paths are guaranteed to be uniform.
(**EDIT**: just noticed that because of the supertrait relationship, you cannot actually implement `LayoutOf` yourself, the blanket `impl` fully covers all possible context types that could ever implement it)
Part of the motivation for this shape of API is that I've been working on querifying `FnAbi::of_*`, and what I want/need to introduce for that looks a lot like the setup in this PR - in particular, it's harder to express the `FnAbi` methods in `rustc_target`, since they're much more tied to `rustc` concepts.
r? `@nagisa` cc `@oli-obk` `@bjorn3`
Introduce `let...else`
Tracking issue: #87335
The trickiest part for me was enforcing the diverging else block with clear diagnostics. Perhaps the obvious solution is to expand to `let _: ! = ..`, but I decided against this because, when a "mismatched type" error is found in typeck, there is no way to trace where in the HIR the expected type originated, AFAICT. In order to pass down this information, I believe we should introduce `Expectation::LetElseNever(HirId)` or maybe add `HirId` to `Expectation::HasType`, but I left that as a future enhancement. For now, I simply assert that the block is `!` with a custom `ObligationCauseCode`, and I think this is clear enough, at least to start. The downside here is that the error points at the entire block rather than the specific expression with the wrong type. I left a todo to this effect.
Overall, I believe this PR is feature-complete with regard to the RFC.
Warn when [T; N].into_iter() is ambiguous in the new edition.
Fixes https://github.com/rust-lang/rust/issues/88475
In https://github.com/rust-lang/rust/issues/88475, a situation was found where `[T; N].into_iter()` becomes *ambiguous* in the new edition. This is different than the case where `(&[T; N]).into_iter()` resolves differently, which was the only case handled by the `array_into_iter` lint. This is almost identical to the new-traits-in-the-prelude problem. Effectively, due to the array-into-iter hack disappearing in Rust 2021, we effectively added `IntoIterator` to the 'prelude' in Rust 2021 specifically for arrays.
This modifies the prelude collisions lint to detect that case and emit a `array_into_iter` lint in that case.
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`
Refactor `named_asm_labels` to a HIR lint
As discussed on #88169, the `named_asm_labels` lint could be moved to a HIR lint. That allows future lints or custom plugins or clippy lints to more easily access the `asm!` macro's data and create better error messages with the lints.
Use custom wrap-around type instead of RangeInclusive
Two reasons:
1. More memory is allocated than necessary for `valid_range` in `Scalar`. The range is not used as an iterator and `exhausted` is never used.
2. `contains`, `count` etc. methods in `RangeInclusive` are doing very unhelpful(and dangerous!) things when used as a wrap-around range. - In general this PR wants to limit potentially confusing methods, that have a low probability of working.
Doing a local perf run, every metric shows improvement except for instructions.
Max-rss seem to have a very consistent improvement.
Sorry - newbie here, probably doing something wrong.
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.
Improve wording of the `drop_bounds` lint
This PR addresses #86653. The issue is sort of a false positive of the `drop_bounds` lint, but I would argue that the best solution for #86653 is simply a rewording of the warning message and lint description, because even if the lint is _technically_ wrong, it still forces the programmer to think about what they are doing, and they can always use `#[allow(drop_bounds)]` if they think that they really need the `Drop` bound.
There are two issues with the current warning message and lint description:
- First, it says that `Drop` bounds are "useless", which is technically incorrect because they actually do have the effect of allowing you e.g. to call methods that also have a `Drop` bound on their generic arguments for some reason. I have changed the wording to emphasize not that the bound is "useless", but that it is most likely not what was intended.
- Second, it claims that `std::mem::needs_drop` detects whether a type has a destructor. But I think this is also technically wrong: The `Drop` bound says whether the type has a destructor or not, whereas `std::mem::needs_drop` also takes nested types with destructors into account, even if the top-level type does not itself have one (although I'm not 100% sure about the exact terminology here, i.e. whether the "drop glue" of the top-level type counts as a destructor or not).
cc `@jonhoo,` does this solve the issue for you?
r? `@GuillaumeGomez`
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.
Force warn improvements
As part of stablization of the `--force-warn` option (#86516) I've made the following changes:
* Error when the `warnings` lint group is based to the `--force-warn` option
* Tests have been updated to make it easier to understand the semantics of `--force-warn`
r? `@nikomatsakis`
Improve non_fmt_panics suggestion based on trait impls.
This improves the non_fmt_panics lint suggestions by checking first which trait (Display or Debug) are actually implemented on the type.
Fixes https://github.com/rust-lang/rust/issues/87313
Fixes https://github.com/rust-lang/rust/issues/87999
Before:
```
help: add a "{}" format string to Display the message
|
2 | panic!("{}", Some(1));
| +++++
help: or use std::panic::panic_any instead
|
2 | std::panic::panic_any(Some(1));
| ~~~~~~~~~~~~~~~~~~~~~
```
After:
```
help: add a "{:?}" format string to use the Debug implementation of `Option<i32>`
|
2 | panic!("{:?}", Some(1));
| +++++++
help: or use std::panic::panic_any instead
|
2 | std::panic::panic_any(Some(1));
| ~~~~~~~~~~~~~~~~~~~~~
```
r? `@estebank`
Detect fake spans in non_fmt_panic lint.
This addresses https://github.com/rust-lang/rust/issues/87621
Some proc_macros claim that the user wrote all of the tokens it outputs, by applying a span from the input to all of the produced tokens. That can result in confusing suggestions, as in #87621. This is a simple patch that avoids suggesting anything for `panic!("{}")` if the span of `"{}"` and `panic!(..)` are identical, which is normally not possible.
Uplift the invalid_atomic_ordering lint from clippy to rustc
This is mostly just a rebase of https://github.com/rust-lang/rust/pull/79654; I've copy/pasted the text from that PR below.
r? `@lcnr` since you reviewed the last one, but feel free to reassign.
---
This is an implementation of https://github.com/rust-lang/compiler-team/issues/390.
As mentioned, in general this turns an unconditional runtime panic into a (compile time) lint failure. It has no false positives, and the only false negatives I'm aware of are if `Ordering` isn't specified directly and is comes from an argument/constant/whatever.
As a result of it having no false positives, and the alternative always being strictly wrong, it's on as deny by default. This seems right.
In the [zulip stream](https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/Uplift.20the.20.60invalid_atomic_ordering.60.20lint.20from.20clippy/near/218483957) `@joshtriplett` suggested that lang team should FCP this before landing it. Perhaps libs team cares too?
---
Some notes on the code for reviewers / others below
## Changes from clippy
The code is changed from [the implementation in clippy](68cf94f6a6/clippy_lints/src/atomic_ordering.rs) in the following ways:
1. Uses `Symbols` and `rustc_diagnostic_item`s instead of string literals.
- It's possible I should have just invoked Symbol::intern for some of these instead? Seems better to use symbol, but it did require adding several.
2. The functions are moved to static methods inside the lint struct, as a way to namespace them.
- There's a lot of other code in that file — which I picked as the location for this lint because `@jyn514` told me that seemed reasonable.
3. Supports unstable AtomicU128/AtomicI128.
- I did this because it was almost easier to support them than not — not supporting them would have (ideally) required finding a way not to give them a `rustc_diagnostic_item`, which would have complicated an already big macro.
- These don't have tests since I wasn't sure if/how I should make tests conditional on whether or not the target has the atomic... This is to a certain extent an issue of 64bit atomics too, but 128-bit atomics are much less common. Regardless, the existing tests should be *more* than thorough enough here.
4. Minor changes like:
- grammar tweaks ("loads cannot have `Release` **and** `AcqRel` ordering" => "loads cannot have `Release` **or** `AcqRel` ordering")
- function renames (`match_ordering_def_path` => `matches_ordering_def_path`),
- avoiding clippy-specific helper methods that don't exist in rustc_lint and didn't seem worth adding for this case (for example `cx.struct_span_lint` vs clippy's `span_lint_and_help` helper).
## Potential issues
(This is just about the code in this PR, not conceptual issues with the lint or anything)
1. I'm not sure if I should have used a diagnostic item for `Ordering` and its variants (I couldn't figure out how really, so if I should do this some pointers would be appreciated).
- It seems possible that failing to do this might possibly mean there are more cases this lint would miss, but I don't really know how `match_def_path` works and if it has any pitfalls like that, so maybe not.
2. I *think* I deprecated the lint in clippy (CC `@flip1995` who asked to be notified about clippy changes in the future in [this comment](https://github.com/rust-lang/rust/pull/75671#issuecomment-718731659)) but I'm not sure if I need to do anything else there.
- I'm kind of hoping CI will catch if I missed anything, since `x.py test src/tools/clippy` fails with a lot of errors with and without my changes (and is probably a nonsense command regardless). Running `cargo test` from src/tools/clippy also fails with unrelated errors that seem like refactorings that didnt update clippy? So, honestly no clue.
3. I wasn't sure if the description/example I gave good. Hopefully it is. The example is less thorough than the one from clippy here: https://rust-lang.github.io/rust-clippy/master/index.html#invalid_atomic_ordering. Let me know if/how I should change it if it needs changing.
4. It pulls in the `if_chain` crate. This crate was already used in clippy, and seems like it's used elsewhere in rustc, but I'm willing to rewrite it to not use this if needed (I'd prefer not to, all things being equal).
- Deprecate clippy::invalid_atomic_ordering
- Use rustc_diagnostic_item for the orderings in the invalid_atomic_ordering lint
- Reduce code duplication
- Give up on making enum variants diagnostic items and just look for
`Ordering` instead
I ran into tons of trouble with this because apparently the change to
store HIR attrs in a side table also gave the DefIds of the
constructor instead of the variant itself. So I had to change
`matches_ordering` to also check the grandparent of the defid as well.
- Rename `atomic_ordering_x` symbols to just the name of the variant
- Fix typos in checks - there were a few places that said "may not be
Release" in the diagnostic but actually checked for SeqCst in the lint.
- Make constant items const
- Use fewer diagnostic items
- Only look at arguments after making sure the method matches
This prevents an ICE when there aren't enough arguments.
- Ignore trait methods
- Only check Ctors instead of going through `qpath_res`
The functions take values, so this couldn't ever be anything else.
- Add if_chain to allowed dependencies
- Fix grammar
- Remove unnecessary allow
Lint against named asm labels
This adds a deny-by-default lint to prevent the use of named labels in inline `asm!`. Without a solution to #81088 about whether the compiler should rewrite named labels or a special syntax for labels, a lint against them should prevent users from writing assembly that could break for internal compiler reasons, such as inlining or anything else that could change the number of actual inline assembly blocks emitted.
This does **not** resolve the issue with rewriting labels, that still needs a decision if the compiler should do any more work to try to make them work.
Try filtering out non-const impls when we expect const impls
**TL;DR**: Associated types on const impls are now bounded; we now disallow calling a const function with bounds when the specified type param only has a non-const impl.
r? `@oli-obk`
Associated functions that contain extern indicator or have `#[rustc_std_internal_symbol]` are reachable
Previously these fails to link with ``undefined reference to `foo'``:
<details>
<summary>Example 1</summary>
```rs
struct AssocFn;
impl AssocFn {
#[no_mangle]
fn foo() {}
}
fn main() {
extern "Rust" {
fn foo();
}
unsafe { foo() }
}
```
([Playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=f1244afcdd26e2a28445f6e82ca46b50))
</details>
<details>
<summary>Example 2</summary>
```rs
#![crate_name = "lib"]
#![crate_type = "lib"]
struct AssocFn;
impl AssocFn {
#[no_mangle]
fn foo() {}
}
```
```rs
extern crate lib;
fn main() {
extern "Rust" {
fn foo();
}
unsafe { foo() }
}
```
</details>
But I believe they should link successfully, because this works:
<details>
```rs
#[no_mangle]
fn foo() {}
fn main() {
extern "Rust" {
fn foo();
}
unsafe { foo() }
}
```
([Playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=789b3f283ee6126f53939429103ed98d))
</details>
This PR fixes the problem, by adding associated functions that have "custom linkage" to `reachable_set`, just like normal functions.
I haven't tested whether #76211 and [Miri](https://github.com/rust-lang/miri/issues/1837) are fixed by this PR yet, but I'm submitting this anyway since this fixes the examples above.
I added a `run-pass` test that combines my two examples above, but I'm not sure if that's the right way to test this. Maybe I should add / modify an existing codegen test (`src/test/codegen/export-no-mangle.rs`?) instead?
Silence non_fmt_panic from external macros.
This stops the non_fmt_panic lint from triggering if a macro from another crate is entirely responsible. In those cases there's nothing that the current crate can/should do.
See also https://github.com/rust-lang/rust/issues/87621#issuecomment-890311054
Allow labeled loops as value expressions for `break`
Fixes#86948. This is currently allowed:
```rust
return 'label: loop { break 'label 42; };
break ('label: loop { break 'label 42; });
break 1 + 'label: loop { break 'label 42; };
break 'outer 'inner: loop { break 'inner 42; };
```
But not this:
```rust
break 'label: loop { break 'label 42; };
```
I have fixed this, so that the above now parses as an unlabeled break with a labeled loop as its value expression.
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.
Store all HIR owners in the same container
This replaces the previous storage in a BTreeMap for each of Item/ImplItem/TraitItem/ForeignItem.
This should allow for a more compact storage.
Based on https://github.com/rust-lang/rust/pull/83114
Currently, we parse macros at the end of a block
(e.g. `fn foo() { my_macro!() }`) as expressions, rather than
statements. This means that a macro invoked in this position
cannot expand to items or semicolon-terminated expressions.
In the future, we might want to start parsing these kinds of macros
as statements. This would make expansion more 'token-based'
(i.e. macro expansion behaves (almost) as if you just textually
replaced the macro invocation with its output). However,
this is a breaking change (see PR #78991), so it will require
further discussion.
Since the current behavior will not be changing any time soon,
we need to address the interaction with the
`SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` lint. Since we are parsing
the result of macro expansion as an expression, we will emit a lint
if there's a trailing semicolon in the macro output. However, this
results in a somewhat confusing message for users, since it visually
looks like there should be no problem with having a semicolon
at the end of a block
(e.g. `fn foo() { my_macro!() }` => `fn foo() { produced_expr; }`)
To help reduce confusion, this commit adds a note explaining
that the macro is being interpreted as an expression. Additionally,
we suggest adding a semicolon after the macro *invocation* - this
will cause us to parse the macro call as a statement. We do *not*
use a structured suggestion for this, since the user may actually
want to remove the semicolon from the macro definition (allowing
the block to evaluate to the expression produced by the macro).
Warn on inert attributes used on bang macro invocation
These attributes are currently discarded.
This may change in the future (see #63221), but for now,
placing inert attributes on a macro invocation does nothing,
so we should warn users about it.
Technically, it's possible for there to be attribute macro
on the same macro invocation (or at a higher scope), which
inspects the inert attribute. For example:
```rust
#[look_for_inline_attr]
#[inline]
my_macro!()
#[look_for_nested_inline]
mod foo { #[inline] my_macro!() }
```
However, this would be a very strange thing to do.
Anyone running into this can manually suppress the warning.
These attributes are currently discarded.
This may change in the future (see #63221), but for now,
placing inert attributes on a macro invocation does nothing,
so we should warn users about it.
Technically, it's possible for there to be attribute macro
on the same macro invocation (or at a higher scope), which
inspects the inert attribute. For example:
```rust
#[look_for_inline_attr]
#[inline]
my_macro!()
#[look_for_nested_inline]
mod foo { #[inline] my_macro!() }
```
However, this would be a very strange thing to do.
Anyone running into this can manually suppress the warning.
Make `--force-warns` a normal lint level option
Now that `ForceWarn` is a lint level, there's no reason `--force-warns` should be treated differently from other options that set lint levels. This merges the `ForceWarn` handling in with the other lint level command line options. It also unifies all of the relevant selection logic in `compiler/rustc_lint/src/levels.rs`, rather than having some of it weirdly elsewhere.
Fixes#86958, which arose from the special-cased handling of `ForceWarn` having had an error in it.
Compute a better `lint_node_id` during expansion
When we need to emit a lint at a macro invocation, we currently use the
`NodeId` of its parent definition (e.g. the enclosing function). This
means that any `#[allow]` / `#[deny]` attributes placed 'closer' to the
macro (e.g. on an enclosing block or statement) will have no effect.
This commit computes a better `lint_node_id` in `InvocationCollector`.
When we visit/flat_map an AST node, we assign it a `NodeId` (earlier
than we normally would), and store than `NodeId` in current
`ExpansionData`. When we collect a macro invocation, the current
`lint_node_id` gets cloned along with our `ExpansionData`, allowing it
to be used if we need to emit a lint later on.
This improves the handling of `#[allow]` / `#[deny]` for
`SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` and some `asm!`-related lints.
The 'legacy derive helpers' lint retains its current behavior
(I've inlined the now-removed `lint_node_id` function), since
there isn't an `ExpansionData` readily available.
Based on the conversation in #86747.
Explanation
-----------
A trait object bound of the form `dyn Drop` is most likely misleading
and not what the programmer intended.
`Drop` bounds do not actually indicate whether a type can be trivially
dropped or not, because a composite type containing `Drop` types does
not necessarily implement `Drop` itself. Naïvely, one might be tempted
to write a deferred drop system, to pull cleaning up memory out of a
latency-sensitive code path, using `dyn Drop` trait objects. However,
this breaks down e.g. when `T` is `String`, which does not implement
`Drop`, but should probably be accepted.
To write a trait object bound that accepts anything, use a placeholder
trait with a blanket implementation.
```rust
trait Placeholder {}
impl<T> Placeholder for T {}
fn foo(_x: Box<dyn Placeholder>) {}
```
Fix internal `default_hash_types` lint to use resolved path
I run into false positives now and then (mostly in Clippy) when I want to name some util after HashMap.
Remove `missing_docs` lint on private 2.0 macros
798baebde1/compiler/rustc_lint/src/builtin.rs (L573-L584)
This code is the source of #57569. The problem is subtle, so let me point it out. This code makes the mistake of assuming that all of the macros in `krate.exported_macros` are exported.
...Yeah. For some historical reason, all `macro` macros are marked as exported, regardless of whether they actually are, which is dreadfully confusing. It would be more accurate to say that `exported_macros` currently contains only macros that have paths.
This PR renames `exported_macros` to `importable_macros`, since these macros can be imported with `use` while others cannot. It also fixes the code above to no longer lint on private `macro` macros, since the `missing_docs` lint should only appear on exported items.
Fixes#57569.
Support lint tool names in rustc command line options
When rustc is running without a lint tool such as clippy enabled, options for lints such as `clippy::foo` are meant to be ignored. This was already working for those specified by attrs, such as `#![allow(clippy::foo)]`, but this did not work for command line arguments like `-A clippy::foo`. This PR fixes that issue.
Note that we discovered this issue while discussing https://github.com/rust-lang/cargo/issues/5034.
Fixes#86628.
This change merges `check_lint_and_tool_name` into `check_lint_name` in
order to avoid having two very similar functions.
Also adds the `.stderr` file back for the test case, since apparently
it is still needed.
Only include lint in future_incompatible lint group if not an edition lint
A follow up to #86330 - this only includes lints annotated with `FutureIncompatibleInfo` in the `future_incompatibile` lint group if the future compatibility is not tied to an edition.
We probably want to rename `FutureIncompatibleInfo` to something else since this type is now used to indicate future breakages of all kinds (even those that happen in editions). I'd prefer to do that in a separate PR though.
r? `@nikomatsakis`
Don't make `rustc_insignificant_dtor` feature gate
This isn't a feature gate, it's an attribute that is feature gated behind the `rustc_attrs` attribute. Closes#85680.
Turn non_fmt_panic into a future_incompatible edition lint.
This turns the `non_fmt_panic` lint into a future_incompatible edition lint, so it becomes part of the `rust_2021_compatibility` group. See https://github.com/rust-lang/rust/issues/85894.
This lint produces both warnings about semantical changes (e.g. `panic!("{{")`) and things that will become hard errors (e.g. `panic!("{")`). So I added a `explain_reason: false` that supresses the default "this will become a hard error" or "the semantics will change" message, and instead added a note depending on the situation. (cc `@rylev)`
r? `@nikomatsakis`
This prevents mistakes where the feature is in the list of incomplete
features but not actually a feature by making the incompleteness a part
of the declaration.
Reserve prefixed identifiers and literals (RFC 3101)
This PR denies any identifiers immediately followed by one of three tokens `"`, `'` or `#`, which is stricter than the requirements of RFC 3101 but may be necessary according to the discussion at [Zulip].
[Zulip]: https://rust-lang.zulipchat.com/#narrow/stream/268952-edition-2021/topic/reserved.20prefixes/near/238470099
The tracking issue #84599 says we'll add a feature gate named `reserved_prefixes`, but I don't think I can do this because it is impossible for the lexer to know whether a feature is enabled or not. I guess determining the behavior by the edition information should be enough.
Fixes#84599
Remove `doc(include)`
This nightly feature is redundant now that `extended_key_value_attributes` is stable (https://github.com/rust-lang/rust/pull/83366). `@rust-lang/rustdoc` not sure if you think this needs FCP; there was already an FCP in #82539, but technically it was for deprecating, not removing the feature altogether.
This should not be merged before #83366.
cc `@petrochenkov`
Support for force-warns
Implements https://github.com/rust-lang/rust/issues/85512.
This PR adds a new command line option `force-warns` which will force the provided lints to warn even if they are allowed by some other mechanism such as `#![allow(warnings)]`.
Some remaining issues:
* https://github.com/rust-lang/rust/issues/85512 mentions that `force-warns` should also be capable of taking lint groups instead of individual lints. This is not implemented.
* If a lint has a higher warning level than `warn`, this will cause that lint to warn instead. We probably want to allow the lint to error if it is set to a higher lint and is not allowed somewhere else.
* One test is currently ignored because it's not working - when a deny-by-default lint is allowed, it does not currently warn under `force-warns`. I'm not sure why, but I wanted to get this in before the weekend.
r? `@nikomatsakis`
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.
Use pattern matching instead of checking lengths explicitly
This piece of code checks that there are exaclty two variants, one having
exactly one field, the other having exactly zero fields. If any of these
conditions is violated, it returns `None`. Otherwise it assigns that one
field's ty to `field_ty`.
Instead of fiddling with indices and length checks explicitly, use pattern
matching to simplify this.
`@rustbot` modify labels +C-cleanup +T-compiler
This piece of code checks that there are exaclty two variants, one having
exactly one field, the other having exactly zero fields. If any of these
conditions is violated, it returns `None`. Otherwise it assigns that one
field's ty to `field_ty`.
Instead of fiddling with indices and length checks explicitly, use pattern
matching to simplify this.
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.
This PR implements span quoting, allowing proc-macros to produce spans
pointing *into their own crate*. This is used by the unstable
`proc_macro::quote!` macro, allowing us to get error messages like this:
```
error[E0412]: cannot find type `MissingType` in this scope
--> $DIR/auxiliary/span-from-proc-macro.rs:37:20
|
LL | pub fn error_from_attribute(_args: TokenStream, _input: TokenStream) -> TokenStream {
| ----------------------------------------------------------------------------------- in this expansion of procedural macro `#[error_from_attribute]`
...
LL | field: MissingType
| ^^^^^^^^^^^ not found in this scope
|
::: $DIR/span-from-proc-macro.rs:8:1
|
LL | #[error_from_attribute]
| ----------------------- in this macro invocation
```
Here, `MissingType` occurs inside the implementation of the proc-macro
`#[error_from_attribute]`. Previosuly, this would always result in a
span pointing at `#[error_from_attribute]`
This will make many proc-macro-related error message much more useful -
when a proc-macro generates code containing an error, users will get an
error message pointing directly at that code (within the macro
definition), instead of always getting a span pointing at the macro
invocation site.
This is implemented as follows:
* When a proc-macro crate is being *compiled*, it causes the `quote!`
macro to get run. This saves all of the sapns in the input to `quote!`
into the metadata of *the proc-macro-crate* (which we are currently
compiling). The `quote!` macro then expands to a call to
`proc_macro::Span::recover_proc_macro_span(id)`, where `id` is an
opaque identifier for the span in the crate metadata.
* When the same proc-macro crate is *run* (e.g. it is loaded from disk
and invoked by some consumer crate), the call to
`proc_macro::Span::recover_proc_macro_span` causes us to load the span
from the proc-macro crate's metadata. The proc-macro then produces a
`TokenStream` containing a `Span` pointing into the proc-macro crate
itself.
The recursive nature of 'quote!' can be difficult to understand at
first. The file `src/test/ui/proc-macro/quote-debug.stdout` shows
the output of the `quote!` macro, which should make this eaier to
understand.
This PR also supports custom quoting spans in custom quote macros (e.g.
the `quote` crate). All span quoting goes through the
`proc_macro::quote_span` method, which can be called by a custom quote
macro to perform span quoting. An example of this usage is provided in
`src/test/ui/proc-macro/auxiliary/custom-quote.rs`
Custom quoting currently has a few limitations:
In order to quote a span, we need to generate a call to
`proc_macro::Span::recover_proc_macro_span`. However, proc-macros
support renaming the `proc_macro` crate, so we can't simply hardcode
this path. Previously, the `quote_span` method used the path
`crate::Span` - however, this only works when it is called by the
builtin `quote!` macro in the same crate. To support being called from
arbitrary crates, we need access to the name of the `proc_macro` crate
to generate a path. This PR adds an additional argument to `quote_span`
to specify the name of the `proc_macro` crate. Howver, this feels kind
of hacky, and we may want to change this before stabilizing anything
quote-related.
Additionally, using `quote_span` currently requires enabling the
`proc_macro_internals` feature. The builtin `quote!` macro
has an `#[allow_internal_unstable]` attribute, but this won't work for
custom quote implementations. This will likely require some additional
tricks to apply `allow_internal_unstable` to the span of
`proc_macro::Span::recover_proc_macro_span`.
Update BARE_TRAIT_OBJECT and ELLIPSIS_INCLUSIVE_RANGE_PATTERNS to errors in Rust 2021
This addresses https://github.com/rust-lang/rust/pull/81244 by updating two lints to errors in the Rust 2021 edition.
r? `@estebank`
Stablize `non-ascii-idents`
This is the stablization PR for RFC 2457. Currently this is waiting on fcp in [tracking issue](https://github.com/rust-lang/rust/issues/55467).
r? `@Manishearth`
add lint deref_nullptr detecting when a null ptr is dereferenced
fixes#83856
changelog: add lint that detect code like
```rust
unsafe {
&*core::ptr::null::<i32>()
};
unsafe {
addr_of!(std::ptr::null::<i32>())
};
let x: i32 = unsafe {*core::ptr::null()};
let x: i32 = unsafe {*core::ptr::null_mut()};
unsafe {*(0 as *const i32)};
unsafe {*(core::ptr::null() as *const i32)};
```
```
warning: Dereferencing a null pointer causes undefined behavior
--> src\main.rs:5:26
|
5 | let x: i32 = unsafe {*core::ptr::null()};
| ^^^^^^^^^^^^^^^^^^
| |
| a null pointer is dereferenced
| this code causes undefined behavior when executed
|
= note: `#[warn(deref_nullptr)]` on by default
```
Limitation:
It does not detect code like
```rust
const ZERO: usize = 0;
unsafe {*(ZERO as *const i32)};
```
or code where `0` is not directly a literal
Found with https://github.com/est31/warnalyzer.
Dubious changes:
- Is anyone else using rustc_apfloat? I feel weird completely deleting
x87 support.
- Maybe some of the dead code in rustc_data_structures, in case someone
wants to use it in the future?
- Don't change rustc_serialize
I plan to scrap most of the json module in the near future (see
https://github.com/rust-lang/compiler-team/issues/418) and fixing the
tests needed more work than I expected.
TODO: check if any of the comments on the deleted code should be kept.
Add function core::iter::zip
This makes it a little easier to `zip` iterators:
```rust
for (x, y) in zip(xs, ys) {}
// vs.
for (x, y) in xs.into_iter().zip(ys) {}
```
You can `zip(&mut xs, &ys)` for the conventional `iter_mut()` and
`iter()`, respectively. This can also support arbitrary nesting, where
it's easier to see the item layout than with arbitrary `zip` chains:
```rust
for ((x, y), z) in zip(zip(xs, ys), zs) {}
for (x, (y, z)) in zip(xs, zip(ys, zs)) {}
// vs.
for ((x, y), z) in xs.into_iter().zip(ys).zip(xz) {}
for (x, (y, z)) in xs.into_iter().zip((ys.into_iter().zip(xz)) {}
```
It may also format more nicely, especially when the first iterator is a
longer chain of methods -- for example:
```rust
iter::zip(
trait_ref.substs.types().skip(1),
impl_trait_ref.substs.types().skip(1),
)
// vs.
trait_ref
.substs
.types()
.skip(1)
.zip(impl_trait_ref.substs.types().skip(1))
```
This replaces the tuple-pair `IntoIterator` in #78204.
There is prior art for the utility of this in [`itertools::zip`].
[`itertools::zip`]: https://docs.rs/itertools/0.10.0/itertools/fn.zip.html
Allow registering tool lints with `register_tool`
Previously, there was no way to add a custom tool prefix, even if the tool
itself had registered a lint:
```rust
#![feature(register_tool)]
#![register_tool(xyz)]
#![warn(xyz::my_lint)]
```
```
$ rustc unknown-lint.rs --crate-type lib
error[E0710]: an unknown tool name found in scoped lint: `xyz::my_lint`
--> unknown-lint.rs:3:9
|
3 | #![warn(xyz::my_lint)]
| ^^^
```
This allows opting-in to lints from other tools using `register_tool`.
cc https://github.com/rust-lang/rust/issues/66079#issuecomment-788589193, ``@chorman0773``
r? ``@petrochenkov``
ast/hir: Rename field-related structures
I always forget what `ast::Field` and `ast::StructField` mean despite working with AST for long time, so this PR changes the naming to less confusing and more consistent.
- `StructField` -> `FieldDef` ("field definition")
- `Field` -> `ExprField` ("expression field", not "field expression")
- `FieldPat` -> `PatField` ("pattern field", not "field pattern")
Various visiting and other methods working with the fields are renamed correspondingly too.
The second commit reduces the size of `ExprKind` by boxing fields of `ExprKind::Struct` in preparation for https://github.com/rust-lang/rust/pull/80080.
Previously, there was no way to add a custom tool prefix, even if the tool
itself had registered a lint:
```
#![feature(register_tool)]
#![register_tool(xyz)]
#![warn(xyz::my_lint)]
```
```
$ rustc unknown-lint.rs --crate-type lib
error[E0710]: an unknown tool name found in scoped lint: `xyz::my_lint`
--> unknown-lint.rs:3:9
|
3 | #![warn(xyz::my_lint)]
| ^^^
```
This allows opting-in to lints from other tools using `register_tool`.
Right now, rustdoc users have an unpleasant situation: they can either
use the new tool lint names (`rustdoc::non_autolinks`) or they can use
the old names (`non_autolinks`). If they use the tool lints, they get a
hard error on stable compilers, because rustc rejects all tool names it
doesn't recognize. If they use the old name, they get a warning to
rename the lint to the new name. The only way to compile without
warnings is to add `#[allow(renamed_removed_lints)]`, which defeats the
whole point of the change: we *want* people to switch to the new name.
To avoid people silencing the lint and never migrating to the tool lint,
this avoids warning about the old name, while still allowing you to use
the new name. Once the new `rustdoc` tool name makes it to the stable
channel, we can change these lints to warn again.
This adds the new lint functions `register_alias` and `register_ignored`
- I didn't see an existing way to do this.
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.
Now that future-incompat-report support has landed in nightly Cargo, we
can start to make progress towards removing the various proc-macro
back-compat hacks that have accumulated in the compiler.
This PR introduces a new lint `proc_macro_back_compat`, which results in
a future-incompat-report entry being generated. All proc-macro
back-compat warnings will be grouped under this lint. Note that this
lint will never actually become a hard error - instead, we will remove
the special cases for various macros, which will cause older versions of
those crates to emit some other error.
I've added code to fire this lint for the `time-macros-impl` case. This
is the easiest case out of all of our current back-compat hacks - the
crate was renamed to `time-macros`, so seeing a filename with
`time-macros-impl` guarantees that an older version of the parent `time`
crate is in use.
When Cargo's future-incompat-report feature gets stabilized, affected
users will start to see future-incompat warnings when they build their
crates.
Rename `rustdoc` to `rustdoc::all`
When rustdoc lints were changed to be tool lints, the `rustdoc` group was removed, leading to spurious warnings like
```
warning: unknown lint: `rustdoc`
```
The lint group still worked when rustdoc ran, since rustdoc added the group itself.
This renames the group to `rustdoc::all` for consistency with `clippy::all` and the rest of the rustdoc lints.
Follow-up to #80527.
r? ``@Manishearth``
or-patterns: disallow in `let` bindings
~~Blocked on https://github.com/rust-lang/rust/pull/81869~~
Disallows top-level or-patterns before type ascription. We want to reserve this syntactic space for possible future generalized type ascription.
r? ``@petrochenkov``
When rustdoc lints were changed to be tool lints, the `rustdoc` group
was removed, leading to spurious warnings like
```
warning: unknown lint: `rustdoc`
```
The lint group still worked when rustdoc ran, since rustdoc added the group itself.
This renames the group to `rustdoc::all` for consistency with
`clippy::all` and the rest of the rustdoc lints.
Implement NOOP_METHOD_CALL lint
Implements the beginnings of https://github.com/rust-lang/lang-team/issues/67 - a lint for detecting noop method calls (e.g, calling `<&T as Clone>::clone()` when `T: !Clone`).
This PR does not fully realize the vision and has a few limitations that need to be addressed either before merging or in subsequent PRs:
* [ ] No UFCS support
* [ ] The warning message is pretty plain
* [ ] Doesn't work for `ToOwned`
The implementation uses [`Instance::resolve`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/instance/struct.Instance.html#method.resolve) which is normally later in the compiler. It seems that there are some invariants that this function relies on that we try our best to respect. For instance, it expects substitutions to have happened, which haven't yet performed, but we check first for `needs_subst` to ensure we're dealing with a monomorphic type.
Thank you to ```@davidtwco,``` ```@Aaron1011,``` and ```@wesleywiser``` for helping me at various points through out this PR ❤️.
Note that the FIXME was removed because this can't be fixed,
`register_renamed` calls LintId::of and there's no LintId for rustdoc
lints when rustc is running.
- Move MISSING_CRATE_LEVEL_DOCS to rustdoc directly
- Update documentation
This also takes the opportunity to make the `no-crate-level-doc-lint`
test more specific.
- Use `register_renamed` when rustdoc is running so the lint will still
be active and use a structured suggestion
- Test the behavior for rustc, not just for rustdoc (because it differs)
- Rename `broken_intra_doc_links` to `rustdoc::broken_intra_doc_links`
- Ensure that the old lint names still work and give deprecation errors
- Register lints even when running doctests
Otherwise, all `rustdoc::` lints would be ignored.
- Register all existing lints as removed
This unfortunately doesn't work with `register_renamed` because tool
lints have not yet been registered when rustc is running. For similar
reasons, `check_backwards_compat` doesn't work either. Call
`register_removed` directly instead.
- Fix fallout
+ Rustdoc lints for compiler/
+ Rustdoc lints for library/
Note that this does *not* suggest `rustdoc::broken_intra_doc_links` for
`rustdoc::intra_doc_link_resolution_failure`, since there was no time
when the latter was valid.
Apply lint restrictions from renamed lints
Previously, if you denied the old name of a renamed lint, it would warn
about using the new name, but otherwise do nothing. Now, it will behave
the same as if you'd used the new name.
Fixes https://github.com/rust-lang/rust/issues/82615.
r? `@ehuss`
Previously, if you denied the old name of a renamed lint, it would warn
about using the new name, but otherwise do nothing. Now, it will behave
the same as if you'd used the new name.
When token-based attribute handling is implemeneted in #80689,
we will need to access tokens from `HasAttrs` (to perform
cfg-stripping), and we will to access attributes from `HasTokens` (to
construct a `PreexpTokenStream`).
This PR merges the `HasAttrs` and `HasTokens` traits into a new
`AstLike` trait. The previous `HasAttrs` impls from `Vec<Attribute>` and `AttrVec`
are removed - they aren't attribute targets, so the impls never really
made sense.
Improve non_fmt_panic lint.
This change:
- fixes the span used by this lint in the case the panic argument is a single macro expansion (e.g. `panic!(a!())`);
- adds a suggestion for `panic!(format!(..))` to remove `format!()` instead of adding `"{}", ` or using `panic_any` like it does now; and
- fixes the incorrect suggestion to replace `panic![123]` by `panic_any(123]`.
Fixes#82109.
Fixes#82110.
Fixes#82111.
Example output:
```
warning: panic message is not a string literal
--> src/main.rs:8:12
|
8 | panic!(format!("error: {}", "oh no"));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(non_fmt_panic)]` on by default
= note: this is no longer accepted in Rust 2021
= note: the panic!() macro supports formatting, so there's no need for the format!() macro here
help: remove the `format!(..)` macro call
|
8 | panic!("error: {}", "oh no");
| -- --
```
r? `@estebank`
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.
Add 'consider using' message to overflowing_literals
Fixes#79744.
Ironically, the `overflowing_literals` handler for binary or hex already
had this message! You would think it would be the other way around :)
cc ```@scottmcm```
Rename HIR UnOp variants
This renames the variants in HIR UnOp from
enum UnOp {
UnDeref,
UnNot,
UnNeg,
}
to
enum UnOp {
Deref,
Not,
Neg,
}
Motivations:
- This is more consistent with the rest of the code base where most enum
variants don't have a prefix.
- These variants are never used without the `UnOp` prefix so the extra
`Un` prefix doesn't help with readability. E.g. we don't have any
`UnDeref`s in the code, we only have `UnOp::UnDeref`.
- MIR `UnOp` type variants don't have a prefix so this is more
consistent with MIR types.
- "un" prefix reads like "inverse" or "reverse", so as a beginner in
rustc code base when I see "UnDeref" what comes to my mind is
something like `&*` instead of just `*`.
This renames the variants in HIR UnOp from
enum UnOp {
UnDeref,
UnNot,
UnNeg,
}
to
enum UnOp {
Deref,
Not,
Neg,
}
Motivations:
- This is more consistent with the rest of the code base where most enum
variants don't have a prefix.
- These variants are never used without the `UnOp` prefix so the extra
`Un` prefix doesn't help with readability. E.g. we don't have any
`UnDeref`s in the code, we only have `UnOp::UnDeref`.
- MIR `UnOp` type variants don't have a prefix so this is more
consistent with MIR types.
- "un" prefix reads like "inverse" or "reverse", so as a beginner in
rustc code base when I see "UnDeref" what comes to my mind is
something like "&*" instead of just "*".
This allows a build system to indicate a location in its own dependency
specification files (eg Cargo's `Cargo.toml`) which can be reported
along side any unused crate dependency.
This supports several types of location:
- 'json' - provide some json-structured data, which is included in the json diagnostics
in a `tool_metadata` field
- 'raw' - emit the provided string into the output. This also appears as a json string in
`tool_metadata`.
If no `--extern-location` is explicitly provided then a default json entry of the form
`"tool_metadata":{"name":<cratename>,"path":<cratepath>}` is emitted.
Add lint for `panic!(123)` which is not accepted in Rust 2021.
This extends the `panic_fmt` lint to warn for all cases where the first argument cannot be interpreted as a format string, as will happen in Rust 2021.
It suggests to add `"{}",` to format the message as a string. In the case of `std::panic!()`, it also suggests the recently stabilized
`std::panic::panic_any()` function as an alternative.
It renames the lint to `non_fmt_panic` to match the lint naming guidelines.
This is part of #80162.
r? ```@estebank```
introduce future-compatibility warning for forbidden lint groups
We used to ignore `forbid(group)` scenarios completely. This changed in #78864, but that led to a number of regressions (#80988, #81218).
This PR introduces a future compatibility warning for the case where a group is forbidden but then an individual lint within that group is allowed. We now issue a FCW when we see the "allow", but permit it to take effect.
r? ``@Mark-Simulacrum``
This extends the `panic_fmt` lint to warn for all cases where the first
argument cannot be interpreted as a format string, as will happen in
Rust 2021.
It suggests to add `"{}", ` to format the message as a string. In the
case of `std::panic!()`, it also suggests the recently stabilized
`std::panic::panic_any()` function as an alternative.
It renames the lint to `non_fmt_panic` to match the lint naming
guidelines.
We used to ignore `forbid(group)` scenarios completely. This changed
in #78864, but that led to a number of regressions (#80988, #81218).
This PR introduces a future compatibility warning for the case where
a group is forbidden but then an individual lint within that group
is allowed. We now issue a FCW when we see the "allow", but permit
it to take effect.
Fix early lints inside an async desugaring
Fixes#81531
When we buffer an early lint for a macro invocation,
we need to determine which NodeId to take the lint level from.
Currently, we use the NodeId of the closest def parent. However, if
the macro invocation is inside the desugared closure from an `async fn`
or async closure, that NodeId does not actually exist in the AST.
This commit uses the parent of a desugared closure when computing
`lint_node_id`, which is something that actually exists in the AST (an
`async fn` or async closure).
Fixes#81531
When we buffer an early lint for a macro invocation,
we need to determine which NodeId to take the lint level from.
Currently, we use the `NodeId` of the closest def parent. However, if
the macro invocation is inside the desugared closure from an `async fn`
or async closure, that `NodeId` does not actually exist in the AST.
This commit explicitly calls `check_lint` for the `NodeId`s of closures
desugared from async expressions, ensuring that we do not miss any
buffered lints.
Box the biggest ast::ItemKind variants
This PR is a different approach on https://github.com/rust-lang/rust/pull/81400, aiming to save memory in humongous ASTs.
The three affected item kind enums are:
- `ast::ItemKind` (208 -> 112 bytes)
- `ast::AssocItemKind` (176 -> 72 bytes)
- `ast::ForeignItemKind` (176 -> 72 bytes)
Implement Rust 2021 panic
This implements the Rust 2021 versions of `panic!()`. See https://github.com/rust-lang/rust/issues/80162 and https://github.com/rust-lang/rfcs/pull/3007.
It does so by replacing `{std, core}::panic!()` by a bulitin macro that expands to either `$crate::panic::panic_2015!(..)` or `$crate::panic::panic_2021!(..)` depending on the edition of the caller.
This does not yet make std's panic an alias for core's panic on Rust 2021 as the RFC proposes. That will be a separate change: c5273bdfb2 That change is blocked on figuring out what to do with https://github.com/rust-lang/rust/issues/80846 first.
clashing_extern_declarations: Use symbol interning to avoid string alloc.
Use symbol interning as a hack to avoid allocating a string for every symbol name we store in the seen set. This hopefully addresses the minor perf regression described in https://github.com/rust-lang/rust/pull/80009#issuecomment-763526902.
r? `@nagisa`
Improve safety of `LateContext::qpath_res`
This is my first rustc code change, inspired by hacking on clippy!
The first change is to clear cached `TypeckResults` from `LateContext` when visiting a nested item. I took a hint from [here](5e91c4ecc0/compiler/rustc_privacy/src/lib.rs (L1300)).
Clippy has a `qpath_res` util function to avoid a possible ICE in `LateContext::qpath_res`. But the docs of `LateContext::qpath_res` promise no ICE. So this updates the `LateContext` method to keep its promises, and removes the util function.
Related: rust-lang/rust-clippy#4545
CC ````````````@eddyb```````````` since you've done related work
CC ````````````@flip1995```````````` FYI
Refractor a few more types to `rustc_type_ir`
In the continuation of #79169, ~~blocked on that PR~~.
This PR:
- moves `IntVarValue`, `FloatVarValue`, `InferTy` (and friends) and `Variance`
- creates the `IntTy`, `UintTy` and `FloatTy` enums in `rustc_type_ir`, based on their `ast` and `chalk_ir` equilavents, and uses them for types in the rest of the compiler.
~~I will split up that commit to make this easier to review and to have a better commit history.~~
EDIT: done, I split the PR in commits of 200-ish lines each
r? `````@nikomatsakis````` cc `````@jackh726`````
Fix <unknown> queries and add more timing info to render_html
Closes https://github.com/rust-lang/rust/issues/81251.
## Fix `<unknown>` queries
This happened because `alloc_query_strings` was never called.
## Add more timing info to render_html
This still has some issues I'm not sure how to work out:
- `create_renderer` and `renderer_after_krate` aren't shown by default.
I want something like `verbose_generic_activity_with_arg`, but it doesn't exist.
I'm also not sure how to show activities that aren't on by default - I
tried `-Z self-profile -Z self-profile-args=all`, but it didn't show up.
r? `@wesleywiser`
Gracefully handle loop labels missing leading `'` in different positions
Fix#81192.
* Account for labels when suggesting `loop` instead of `while true`
* Suggest `'a` when given `a` only when appropriate
* Add loop head span to hir
* Tweak error for invalid `break expr`
* Add more misspelled label tests
* Avoid emitting redundant "unused label" lint
* Parse loop labels missing a leading `'`
Each commit can be reviewed in isolation.
Fix formatting for removed lints
- Don't add backticks for the reason a lint was removed. This is almost
never a code block, and when it is the backticks should be in the reason
itself.
- Don't assume clippy is the only tool that needs to be checked for
backwards compatibility
I split this out of https://github.com/rust-lang/rust/pull/80527/ because it kept causing tests to fail, and it's a good change to have anyway.
r? `@flip1995`
Prevents LateContext::maybe_typeck_results() from returning data in a
nested item without a body. Consequently, LateContext::qpath_res is less
likely to ICE when called in a nested item. Would have prevented
rust-lang/rust-clippy#4545, presumably.
- Don't add backticks for the reason a lint was removed. This is almost
never a code block, and when it is the backticks should be in the reason
itself.
- Don't assume clippy is the only tool that needs to be checked for
backwards compatibility
This copies the unknown_lints code clippy uses for its
unknown_clippy_lints lint to rustc. The unknown_clippy_lints code is
more advanced, because it doesn't suggest renamed or removed lints and
correctly suggest lower casing lints.
Previously, clippy (and any other tool emitting lints) had to have their
own separate UNKNOWN_LINTS pass, because the compiler assumed any tool
lint could be valid. Now, as long as any lint starting with the tool
prefix exists, the compiler will warn when an unknown lint is present.
Separate out a `hir::Impl` struct
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
See `rustc_save_analysis::dump_visitor::process_impl` or `rustdoc::clean::clean_impl` for a good example of how this makes `impl`s easier to work with.
r? `@petrochenkov` maybe?
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
Add `#[track_caller]` to `bug!` and `register_renamed`
Before:
```
thread 'rustc' panicked at 'compiler/rustc_lint/src/context.rs:267:18: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:34:26
```
After:
```
thread 'rustc' panicked at 'src/librustdoc/core.rs:455:24: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:35:26
```
The reason I added it to `register_renamed` too is that any panic in
that function will be the caller's fault.
Before:
```
thread 'rustc' panicked at 'compiler/rustc_lint/src/context.rs:267:18: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:34:26
```
After:
```
thread 'rustc' panicked at 'src/librustdoc/core.rs:455:24: invalid lint renaming of broken_intra_doc_links to rustdoc::broken_intra_doc_links', compiler/rustc_middle/src/util/bug.rs:35:26
```
The reason I added it to `register_renamed` too is that any panic in
that function will be the caller's fault.
Rename rustc_middle::lint::LintSource
Rename [`rustc_middle::lint::LintSource`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/lint/enum.LintSource.html) to `rustc_middle::lint::LintLevelSource`.
This enum represents the source of a *lint level*, not a lint. This should improve code readability.
Update: Also documents `rustc_middle::lint::LevelSource` to clarify.
Rename `overlapping_patterns` lint
As discussed in https://github.com/rust-lang/rust/issues/65477. I also tweaked a few things along the way.
r? `@varkor`
`@rustbot` modify labels: +A-exhaustiveness-checking
Use true previous lint level when detecting overriden forbids
Previously, cap-lints was ignored when checking the previous forbid level, which
meant that it was a hard error to do so. This is different from the normal
behavior of lints, which are silenced by cap-lints; if the forbid would not take
effect regardless, there is not much point in complaining about the fact that we
are reducing its level.
It might be considered a bug that even `--cap-lints deny` would suffice to
silence the error on overriding forbid, depending on if one cares about failing
the build or precisely forbid being set. But setting cap-lints to deny is quite
odd and not really done in practice, so we don't try to handle it specially.
This also unifies the code paths for nested and same-level scopes. However, the
special case for CLI lint flags is left in place (introduced by #70918) to fix
the regression noted in #70819. That means that CLI flags do not lint on forbid
being overridden by a non-forbid level. It is unclear whether this is a bug or a
desirable feature, but it is certainly inconsistent. CLI flags are a
sufficiently different "type" of place though that this is deemed out of scope
for this commit.
r? `@pnkfelix` perhaps?
cc #77713 -- not marking as "Fixes" because of the lack of proper unused attribute handling in this PR
This preserves the current lint behavior for now.
Linting after item statements currently prevents the compiler from bootstrapping.
Fixing this is blocked on fixing this upstream in Cargo, and bumping the Cargo
submodule.
rustc_ast currently has a few dependencies on rustc_lexer. Ideally, an AST
would not have any dependency its lexer, for minimizing unnecessarily
design-time dependencies. Breaking this dependency would also have practical
benefits, since modifying rustc_lexer would not trigger a rebuild of rustc_ast.
This commit does not remove the rustc_ast --> rustc_lexer dependency,
but it does remove one of the sources of this dependency, which is the
code that handles fuzzy matching between symbol names for making suggestions
in diagnostics. Since that code depends only on Symbol, it is easy to move
it to rustc_span. It might even be best to move it to a separate crate,
since other tools such as Cargo use the same algorithm, and have simply
contain a duplicate of the code.
This changes the signature of find_best_match_for_name so that it is no
longer generic over its input. I checked the optimized binaries, and this
function was duplicated at nearly every call site, because most call sites
used short-lived iterator chains, generic over Map and such. But there's
no good reason for a function like this to be generic, since all it does
is immediately convert the generic input (the Iterator impl) to a concrete
Vec<Symbol>. This has all of the costs of generics (duplicated method bodies)
with no benefit.
Changing find_best_match_for_name to be non-generic removed about 10KB of
code from the optimized binary. I know it's a drop in the bucket, but we have
to start reducing binary size, and beginning to tame over-use of generics
is part of that.
lint: Do not provide suggestions for non standard characters
Fixes#77273
Only provide suggestions if the case-fixed result is different than the original.
Previously, cap-lints was ignored when checking the previous forbid level, which
meant that it was a hard error to do so. This is different from the normal
behavior of lints, which are silenced by cap-lints; if the forbid would not take
effect regardless, there is not much point in complaining about the fact that we
are reducing its level.
It might be considered a bug that even `--cap-lints deny` would suffice to
silence the error on overriding forbid, depending on if one cares about failing
the build or precisely forbid being set. But setting cap-lints to deny is quite
odd and not really done in practice, so we don't try to handle it specially.
This also unifies the code paths for nested and same-level scopes. However, the
special case for CLI lint flags is left in place (introduced by #70918) to fix
the regression noted in #70819. That means that CLI flags do not lint on forbid
being overridden by a non-forbid level. It is unclear whether this is a bug or a
desirable feature, but it is certainly inconsistent. CLI flags are a
sufficiently different "type" of place though that this is deemed out of scope
for this commit.
rustc_ast: Do not panic by default when visiting macro calls
Panicking by default made sense when we didn't have HIR or MIR and everything worked on AST, but now all AST visitors run early and majority of them have to deal with macro calls, often by ignoring them.
The second commit renames `visit_mac` to `visit_mac_call`, the corresponding structures were renamed earlier in https://github.com/rust-lang/rust/pull/69589.
Fix ICE when a future-incompat-report has its command-line level capped
Fixes#78660
With PR https://github.com/rust-lang/rust/pull/75534 merged, we now run
more lint-related code for future-incompat-report, even when their final
level is Allow. Some lint-related code was not expecting `Level::Allow`,
and had an explicit panic.
This PR explicitly tracks the lint level set on the command line before
`--cap-lints` is applied. This is used to emit a more precise error
note (e.g. we don't say that `-W lint-name` was specified on the
command line just because a lint was capped to Warn). As a result, we
can now correctly emit a note that `-A` was used if we got
`Level::Allow` from the command line (before the cap is applied).
See https://github.com/rust-lang/rust/issues/61733#issuecomment-716188981
We now preserve the trailing semicolon in a macro invocation, even if
the macro expands to nothing. As a result, the following code no longer
compiles:
```rust
macro_rules! empty {
() => { }
}
fn foo() -> bool { //~ ERROR mismatched
{ true } //~ ERROR mismatched
empty!();
}
```
Previously, `{ true }` would be considered the trailing expression, even
though there's a semicolon in `empty!();`
This makes macro expansion more token-based.
Fixes#78660
With PR https://github.com/rust-lang/rust/pull/75534 merged, we now run
more lint-related code for future-incompat-report, even when their final
level is Allow. Some lint-related code was not expecting `Level::Allow`,
and had an explicit panic.
This PR explicitly tracks the lint level set on the command line before
`--cap-lints` is applied. This is used to emit a more precise error
note (e.g. we don't say that `-W lint-name` was specified on the
command line just because a lint was capped to Warn). As a result, we
can now correctly emit a note that `-A` was used if we got
`Level::Allow` from the command line (before the cap is applied).
Implement rustc side of report-future-incompat
cc https://github.com/rust-lang/rust/issues/71249
This is an alternative to `@pnkfelix's` initial implementation in https://github.com/pnkfelix/rust/commits/prototype-rustc-side-of-report-future-incompat (mainly because I started working before seeing that branch 😄 ).
My approach outputs the entire original `Diagnostic`, in a way that is compatible with incremental compilation. This is not yet integrated with compiletest, but can be used manually by passing `-Z emit-future-incompat-report` to `rustc`.
Several changes are made to support this feature:
* The `librustc_session/lint` module is moved to a new crate `librustc_lint_defs` (name bikesheddable). This allows accessing lint definitions from `librustc_errors`.
* The `Lint` struct is extended with an `Option<FutureBreakage>`. When present, it indicates that we should display a lint in the future-compat report. `FutureBreakage` contains additional information that we may want to display in the report (currently, a `date` field indicating when the crate will stop compiling).
* A new variant `rustc_error::Level::Allow` is added. This is used when constructing a diagnostic for a future-breakage lint that is marked as allowed (via `#[allow]` or `--cap-lints`). This allows us to capture any future-breakage diagnostics in one place, while still discarding them before they are passed to the `Emitter`.
* `DiagnosticId::Lint` is extended with a `has_future_breakage` field, indicating whether or not the `Lint` has future breakage information (and should therefore show up in the report).
* `Session` is given access to the `LintStore` via a new `SessionLintStore` trait (since `librustc_session` cannot directly reference `LintStore` without a cyclic dependency). We use this to turn a string `DiagnosticId::Lint` back into a `Lint`, to retrieve the `FutureBreakage` data.
Currently, `FutureBreakage.date` is always set to `None`. However, this could potentially be interpreted by Cargo in the future.
I've enabled the future-breakage report for the `ARRAY_INTO_ITER` lint, which can be used to test out this PR. The intent is to use the field to allow Cargo to determine the date of future breakage (as described in [RFC 2834](https://github.com/rust-lang/rfcs/blob/master/text/2834-cargo-report-future-incompat.md)) without needing to parse the diagnostic itself.
cc `@pnkfelix`
Dogfood {exclusive,half-open} ranges in compiler (nfc)
In particular, this allows us to write more explicit matches that
avoid the pitfalls of using a fully general fall-through case, yet
remain fairly ergonomic. Less logic is in guard cases, more is in
the actual exhaustive case analysis.
No functional changes.
In particular, this allows us to write more explicit matches that
avoid the pitfalls of using a fully general fall-through case, yet
remain fairly ergonomic. Less logic is in guard cases, more is in
the actual exhaustive case analysis.
No functional changes.
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.
```rust
trait Foo {
#[allow(unused_attributes)] #[inline] fn first();
#[inline] #[allow(unused_attributes)] fn second();
}
```
However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).
Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.
This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:
* The `HasAttr` impl for `StmtKind` now returns attributes for
`StmtKind::Item`, treating it just like every other `StmtKind`
variant. The only place relying on the old behavior was macro
which has been updated to explicitly ignore attributes on item
statements. This allows the `unused_doc_comments` lint to fire for
item statements.
* The `early` and `late` lint visitors now activate lint attributes when
invoking the callback for `Stmt`. This ensures that a lint
attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
sibiling attributes on an item statement.
For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
Introduce `TypeVisitor::BreakTy`
Implements MCP rust-lang/compiler-team#383.
r? `@ghost`
cc `@lcnr` `@oli-obk`
~~Blocked on FCP in rust-lang/compiler-team#383.~~
