Migrate some rustc_builtin_macros to SessionDiagnostic
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Part of https://github.com/rust-lang/rust/issues/100717.
pick up abandoned pr: #101935
`@rustbot` label +A-translation
This makes their intent and expected location clearer. We see some
examples where these comments were not clearly separate from `use`
declarations, which made it hard to understand what the comment is
describing.
We already do this for a number of crates, e.g. `rustc_middle`,
`rustc_span`, `rustc_metadata`, `rustc_span`, `rustc_errors`.
For the ones we don't, in many cases the attributes are a mess.
- There is no consistency about order of attribute kinds (e.g.
`allow`/`deny`/`feature`).
- Within attribute kind groups (e.g. the `feature` attributes),
sometimes the order is alphabetical, and sometimes there is no
particular order.
- Sometimes the attributes of a particular kind aren't even grouped
all together, e.g. there might be a `feature`, then an `allow`, then
another `feature`.
This commit extends the existing sorting to all compiler crates,
increasing consistency. If any new attribute line is added there is now
only one place it can go -- no need for arbitrary decisions.
Exceptions:
- `rustc_log`, `rustc_next_trait_solver` and `rustc_type_ir_macros`,
because they have no crate attributes.
- `rustc_codegen_gcc`, because it's quasi-external to rustc (e.g. it's
ignored in `rustfmt.toml`).
When `derive`ing, account for HRTB on `BareFn` fields
When given
```rust
trait SomeTrait {
type SomeType<'a>;
}
#[derive(Clone)]
struct Foo<T: SomeTrait> {
x: for<'a> fn(T::SomeType<'a>)
}
```
expand to
```rust
impl<T: ::core::clone::Clone + SomeTrait> ::core::clone::Clone for Foo<T>
where for<'a> T::SomeType<'a>: ::core::clone::Clone {
#[inline]
fn clone(&self) -> Foo<T> {
Foo { x: ::core::clone::Clone::clone(&self.x) }
}
}
```
instead of the previous invalid
```
impl<T: ::core::clone::Clone + SomeTrait> ::core::clone::Clone for Foo<T>
where T::SomeType<'a>: ::core::clone::Clone {
#[inline]
fn clone(&self) -> Foo<T> {
Foo { x: ::core::clone::Clone::clone(&self.x) }
}
}
```
Fix#122622.
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Currently we have an awkward mix of fallible and infallible functions:
```
new_parser_from_source_str
maybe_new_parser_from_source_str
new_parser_from_file
(maybe_new_parser_from_file) // missing
(new_parser_from_source_file) // missing
maybe_new_parser_from_source_file
source_str_to_stream
maybe_source_file_to_stream
```
We could add the two missing functions, but instead this commit removes
of all the infallible ones and renames the fallible ones leaving us with
these which are all fallible:
```
new_parser_from_source_str
new_parser_from_file
new_parser_from_source_file
source_str_to_stream
source_file_to_stream
```
This requires making `unwrap_or_emit_fatal` public so callers of
formerly infallible functions can still work.
This does make some of the call sites slightly more verbose, but I think
it's worth it for the simpler API. Also, there are two `catch_unwind`
calls and one `catch_fatal_errors` call in this diff that become
removable thanks this change. (I will do that in a follow-up PR.)
Expand `for_loops_over_fallibles` lint to lint on fallibles behind references.
Extends the scope of the (warn-by-default) lint `for_loops_over_fallibles` from just `for _ in x` where `x: Option<_>/Result<_, _>` to also cover `x: &(mut) Option<_>/Result<_>`
```rs
fn main() {
// Current lints
for _ in Some(42) {}
for _ in Ok::<_, i32>(42) {}
// New lints
for _ in &Some(42) {}
for _ in &mut Some(42) {}
for _ in &Ok::<_, i32>(42) {}
for _ in &mut Ok::<_, i32>(42) {}
// Should not lint
for _ in Some(42).into_iter() {}
for _ in Some(42).iter() {}
for _ in Some(42).iter_mut() {}
for _ in Ok::<_, i32>(42).into_iter() {}
for _ in Ok::<_, i32>(42).iter() {}
for _ in Ok::<_, i32>(42).iter_mut() {}
}
```
<details><summary><code>cargo build</code> diff</summary>
```diff
diff --git a/old.out b/new.out
index 84215aa..ca195a7 100644
--- a/old.out
+++ b/new.out
`@@` -1,33 +1,93 `@@`
warning: for loop over an `Option`. This is more readably written as an `if let` statement
--> src/main.rs:3:14
|
3 | for _ in Some(42) {}
| ^^^^^^^^
|
= note: `#[warn(for_loops_over_fallibles)]` on by default
help: to check pattern in a loop use `while let`
|
3 | while let Some(_) = Some(42) {}
| ~~~~~~~~~~~~~~~ ~~~
help: consider using `if let` to clear intent
|
3 | if let Some(_) = Some(42) {}
| ~~~~~~~~~~~~ ~~~
warning: for loop over a `Result`. This is more readably written as an `if let` statement
--> src/main.rs:4:14
|
4 | for _ in Ok::<_, i32>(42) {}
| ^^^^^^^^^^^^^^^^
|
help: to check pattern in a loop use `while let`
|
4 | while let Ok(_) = Ok::<_, i32>(42) {}
| ~~~~~~~~~~~~~ ~~~
help: consider using `if let` to clear intent
|
4 | if let Ok(_) = Ok::<_, i32>(42) {}
| ~~~~~~~~~~ ~~~
-warning: `for-loops-over-fallibles` (bin "for-loops-over-fallibles") generated 2 warnings
- Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.04s
+warning: for loop over a `&Option`. This is more readably written as an `if let` statement
+ --> src/main.rs:7:14
+ |
+7 | for _ in &Some(42) {}
+ | ^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+7 | while let Some(_) = &Some(42) {}
+ | ~~~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+7 | if let Some(_) = &Some(42) {}
+ | ~~~~~~~~~~~~ ~~~
+
+warning: for loop over a `&mut Option`. This is more readably written as an `if let` statement
+ --> src/main.rs:8:14
+ |
+8 | for _ in &mut Some(42) {}
+ | ^^^^^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+8 | while let Some(_) = &mut Some(42) {}
+ | ~~~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+8 | if let Some(_) = &mut Some(42) {}
+ | ~~~~~~~~~~~~ ~~~
+
+warning: for loop over a `&Result`. This is more readably written as an `if let` statement
+ --> src/main.rs:9:14
+ |
+9 | for _ in &Ok::<_, i32>(42) {}
+ | ^^^^^^^^^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+9 | while let Ok(_) = &Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+9 | if let Ok(_) = &Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~ ~~~
+
+warning: for loop over a `&mut Result`. This is more readably written as an `if let` statement
+ --> src/main.rs:10:14
+ |
+10 | for _ in &mut Ok::<_, i32>(42) {}
+ | ^^^^^^^^^^^^^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+10 | while let Ok(_) = &mut Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+10 | if let Ok(_) = &mut Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~ ~~~
+
+warning: `for-loops-over-fallibles` (bin "for-loops-over-fallibles") generated 6 warnings
+ Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.02s
```
</details>
-----
Question:
* ~~Currently, the article `an` is used for `&Option`, and `&mut Option` in the lint diagnostic, since that's what `Option` uses. Is this okay or should it be changed? (likewise, `a` is used for `&Result` and `&mut Result`)~~ The article `a` is used for `&Option`, `&mut Option`, `&Result`, `&mut Result` and (as before) `Result`. Only `Option` uses `an` (as before).
`@rustbot` label +A-lint
This has no noticeable effect, but it makes these cases follow the
guidelines in the comments on `Spacing`, which say that `Joint` should
be used "for each token that (a) should be pretty-printed without a
space after it, and (b) is followed by a punctuation token".
These two tokens are both followed by a comma, which is a punctuation
token.
Translation of the lint message happens when the actual diagnostic is
created, not when the lint is buffered. Generating the message from
BuiltinLintDiag ensures that all required data to construct the message
is preserved in the LintBuffer, eventually allowing the messages to be
moved to fluent.
Remove the `msg` field from BufferedEarlyLint, it is either generated
from the data in the BuiltinLintDiag or stored inside
BuiltinLintDiag::Normal.
Rename Unsafe to Safety
Alternative to #124455, which is to just have one Safety enum to use everywhere, this opens the posibility of adding `ast::Safety::Safe` that's useful for unsafe extern blocks.
This leaves us today with:
```rust
enum ast::Safety {
Unsafe(Span),
Default,
// Safe (going to be added for unsafe extern blocks)
}
enum hir::Safety {
Unsafe,
Safe,
}
```
We would convert from `ast::Safety::Default` into the right Safety level according the context.
Add `ErrorGuaranteed` to `Recovered::Yes` and use it more.
The starting point for this was identical comments on two different fields, in `ast::VariantData::Struct` and `hir::VariantData::Struct`:
```
// FIXME: investigate making this a `Option<ErrorGuaranteed>`
recovered: bool
```
I tried that, and then found that I needed to add an `ErrorGuaranteed` to `Recovered::Yes`. Then I ended up using `Recovered` instead of `Option<ErrorGuaranteed>` for these two places and elsewhere, which required moving `ErrorGuaranteed` from `rustc_parse` to `rustc_ast`.
This makes things more consistent, because `Recovered` is used in more places, and there are fewer uses of `bool` and
`Option<ErrorGuaranteed>`. And safer, because it's difficult/impossible to set `recovered` to `Recovered::Yes` without having emitted an error.
r? `@oli-obk`
The starting point for this was identical comments on two different
fields, in `ast::VariantData::Struct` and `hir::VariantData::Struct`:
```
// FIXME: investigate making this a `Option<ErrorGuaranteed>`
recovered: bool
```
I tried that, and then found that I needed to add an `ErrorGuaranteed`
to `Recovered::Yes`. Then I ended up using `Recovered` instead of
`Option<ErrorGuaranteed>` for these two places and elsewhere, which
required moving `ErrorGuaranteed` from `rustc_parse` to `rustc_ast`.
This makes things more consistent, because `Recovered` is used in more
places, and there are fewer uses of `bool` and
`Option<ErrorGuaranteed>`. And safer, because it's difficult/impossible
to set `recovered` to `Recovered::Yes` without having emitted an error.
Do not add leading asterisk in the `PartialEq`
I think we should address this issue, however I am not exactly sure, if this is the right way to do it. It is related to the #123056.
Imagine the simplified code:
```rust
trait MyTrait {}
impl PartialEq for dyn MyTrait {
fn eq(&self, _other: &Self) -> bool {
true
}
}
#[derive(PartialEq)]
enum Bar {
Foo(Box<dyn MyTrait>),
}
```
On the nightly compiler, the `derive` produces invalid code with the weird error message:
```
error[E0507]: cannot move out of `*__arg1_0` which is behind a shared reference
--> src/main.rs:11:9
|
9 | #[derive(PartialEq)]
| --------- in this derive macro expansion
10 | enum Things {
11 | Foo(Box<dyn MyTrait>),
| ^^^^^^^^^^^^^^^^ move occurs because `*__arg1_0` has type `Box<dyn MyTrait>`, which does not implement the `Copy` trait
|
= note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info)
```
It may be related to the perfect derive problem, although requiring the _type_ to be `Copy` seems unfortunate because it is not necessary. Besides, we are adding the extra dereference only for the diagnostics?
Remove braces when fixing a nested use tree into a single item
[Back in 2019](https://github.com/rust-lang/rust/pull/56645) I added rustfix support for the `unused_imports` lint, to automatically remove them when running `cargo fix`. For the most part this worked great, but when removing all but one childs of a nested use tree it turned `use foo::{Unused, Used}` into `use foo::{Used}`. This is slightly annoying, because it then requires you to run `rustfmt` to get `use foo::Used`.
This PR automatically removes braces and the surrouding whitespace when all but one child of a nested use tree are unused. To get it done I had to add the span of the nested use tree to the AST, and refactor a bit the code I wrote back then.
A thing I noticed is, there doesn't seem to be any `//@ run-rustfix` test for fixing the `unused_imports` lint. I created a test in `tests/suggestions` (is that the right directory?) that for now tests just what I added in the PR. I can followup in a separate PR to add more tests for fixing `unused_lints`.
This PR is best reviewed commit-by-commit.
This moves some code around and adds some documentation comments to make
it easier to understand what's going on with the entrypoint logic, which
is a bit complicated.
The only change in behavior is consolidating the error messages for
unix_sigpipe to make the code slightly simpler.
ast: Generalize item kind visiting
And avoid duplicating logic for visiting `Item`s with different kinds (regular, associated, foreign).
The diff is better viewed with whitespace ignored.
These functions are only used in `rustc_builtin_macros`, so it makes
sense for them to live there. This allows them to be changed from `pub`
to `pub(crate)`.
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\clone.rs:160:9
|
160 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\cmp\partial_ord.rs:72:9
|
72 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\cmp\partial_eq.rs:19:18
|
19 | fn cs_eq(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> BlockOrExpr {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\cmp\ord.rs:42:19
|
42 | pub fn cs_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> BlockOrExpr {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:917:13
|
917 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1406:13
|
1406 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1157:13
|
1157 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1103:13
|
1103 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1080:13
|
1080 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:859:13
|
859 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:805:13
|
805 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:467:13
|
467 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:457:13
|
457 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\mod.rs:120:9
|
120 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1573:13
|
1573 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1556:13
|
1556 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1463:13
|
1463 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:1433:36
|
1433 | fn summarise_struct(&self, cx: &mut ExtCtxt<'_>, struct_def: &VariantData) -> StaticFields {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:953:13
|
953 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:932:13
|
932 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:580:13
|
580 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\generic\mod.rs:989:13
|
989 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\clone.rs:97:9
|
97 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\cmp\eq.rs:52:9
|
52 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\hash.rs:50:9
|
50 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\encodable.rs:150:9
|
150 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\default.rs:176:9
|
176 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\default.rs:106:9
|
106 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\default.rs:57:9
|
57 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\default.rs:84:9
|
84 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\debug.rs:212:9
|
212 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\deriving\debug.rs:48:26
|
48 | fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> BlockOrExpr {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\asm.rs:306:28
|
306 | fn err_duplicate_option(p: &mut Parser<'_>, symbol: Symbol, span: Span) {
| ^^^^^^^^^^^^^^^ help: consider changing to: `&Parser<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\asm.rs:318:8
|
318 | p: &mut Parser<'a>,
| ^^^^^^^^^^^^^^^ help: consider changing to: `&Parser<'a>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\assert.rs:114:25
|
114 | fn parse_assert<'a>(cx: &mut ExtCtxt<'a>, sp: Span, stream: TokenStream) -> PResult<'a, Assert> {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'a>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\asm.rs:32:10
|
32 | ecx: &mut ExtCtxt<'a>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'a>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\test.rs:99:9
|
99 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\source_util.rs:237:9
|
237 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\format.rs:809:10
|
809 | ecx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\format.rs:737:10
|
737 | ecx: &mut ExtCtxt<'a>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'a>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\format.rs:68:24
|
68 | fn parse_args<'a>(ecx: &mut ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<'a, MacroInput> {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'a>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\format.rs:607:10
|
607 | ecx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\edition_panic.rs:43:9
|
43 | cx: &'cx mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\concat_bytes.rs:11:9
|
11 | cx: &mut ExtCtxt<'_>,
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\cfg.rs:38:22
|
38 | fn parse_cfg<'a>(cx: &mut ExtCtxt<'a>, span: Span, tts: TokenStream) -> PResult<'a, ast::MetaItem> {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'a>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_builtin_macros\src\cfg_accessible.rs:13:28
|
13 | fn validate_input<'a>(ecx: &mut ExtCtxt<'_>, mi: &'a ast::MetaItem) -> Option<&'a ast::Path> {
| ^^^^^^^^^^^^^^^^ help: consider changing to: `&ExtCtxt<'_>`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_ref_mut
Experimental feature postfix match
This has a basic experimental implementation for the RFC postfix match (rust-lang/rfcs#3295, #121618). [Liaison is](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Postfix.20Match.20Liaison/near/423301844) ```@scottmcm``` with the lang team's [experimental feature gate process](https://github.com/rust-lang/lang-team/blob/master/src/how_to/experiment.md).
This feature has had an RFC for a while, and there has been discussion on it for a while. It would probably be valuable to see it out in the field rather than continue discussing it. This feature also allows to see how popular postfix expressions like this are for the postfix macros RFC, as those will take more time to implement.
It is entirely implemented in the parser, so it should be relatively easy to remove if needed.
This PR is split in to 5 commits to ease review.
1. The implementation of the feature & gating.
2. Add a MatchKind field, fix uses, fix pretty.
3. Basic rustfmt impl, as rustfmt crashes upon seeing this syntax without a fix.
4. Add new MatchSource to HIR for Clippy & other HIR consumers
Use `ControlFlow` in visitors.
Follow up to #121256
This does have a few small behaviour changes in some diagnostic output where the visitor will now find the first match rather than the last match. The change in `find_anon_types.rs` has the only affected test. I don't see this being an issue as the last occurrence isn't any better of a choice than the first.
Add asm goto support to `asm!`
Tracking issue: #119364
This PR implements asm-goto support, using the syntax described in "future possibilities" section of [RFC2873](https://rust-lang.github.io/rfcs/2873-inline-asm.html#asm-goto).
Currently I have only implemented the `label` part, not the `fallthrough` part (i.e. fallthrough is implicit). This doesn't reduce the expressive though, since you can use label-break to get arbitrary control flow or simply set a value and rely on jump threading optimisation to get the desired control flow. I can add that later if deemed necessary.
r? ``@Amanieu``
cc ``@ojeda``
Existing names for values of this type are `sess`, `parse_sess`,
`parse_session`, and `ps`. `sess` is particularly annoying because
that's also used for `Session` values, which are often co-located, and
it can be difficult to know which type a value named `sess` refers to.
(That annoyance is the main motivation for this change.) `psess` is nice
and short, which is good for a name used this much.
The commit also renames some `parse_sess_created` values as
`psess_created`.
Add newtypes for bool fields/params/return types
Fixed all the cases of this found with some simple searches for `*/ bool` and `bool /*`; probably many more
Trigger `unsafe_code` lint on invocations of `global_asm`
`unsafe_code` already warns about things that don't involve the `unsafe` keyword, e.g. `#[no_mangle]`. This makes it warn on `core::arch::global_asm` too.
Fixes#103078
Currently many diagnostic modifier methods are available on both
`Diagnostic` and `DiagnosticBuilder`. This commit removes most of them
from `Diagnostic`. To minimize the diff size, it keeps them within
`diagnostic.rs` but changes the surrounding `impl Diagnostic` block to
`impl DiagnosticBuilder`. (I intend to move things around later, to give
a more sensible code layout.)
`Diagnostic` keeps a few methods that it still needs, like `sub`,
`arg`, and `replace_args`.
The `forward!` macro, which defined two additional methods per call
(e.g. `note` and `with_note`), is replaced by the `with_fn!` macro,
which defines one additional method per call (e.g. `with_note`). It's
now also only used when necessary -- not all modifier methods currently
need a `with_*` form. (New ones can be easily added as necessary.)
All this also requires changing `trait AddToDiagnostic` so its methods
take `DiagnosticBuilder` instead of `Diagnostic`, which leads to many
mechanical changes. `SubdiagnosticMessageOp` gains a type parameter `G`.
There are three subdiagnostics -- `DelayedAtWithoutNewline`,
`DelayedAtWithNewline`, and `InvalidFlushedDelayedDiagnosticLevel` --
that are created within the diagnostics machinery and appended to
external diagnostics. These are handled at the `Diagnostic` level, which
means it's now hard to construct them via `derive(Diagnostic)`, so
instead we construct them by hand. This has no effect on what they look
like when printed.
There are lots of new `allow` markers for `untranslatable_diagnostics`
and `diagnostics_outside_of_impl`. This is because
`#[rustc_lint_diagnostics]` annotations were present on the `Diagnostic`
modifier methods, but missing from the `DiagnosticBuilder` modifier
methods. They're now present.
This mostly works well, and eliminates a couple of delayed bugs.
One annoying thing is that we should really also add an
`ErrorGuaranteed` to `proc_macro::bridge::LitKind::Err`. But that's
difficult because `proc_macro` doesn't have access to `ErrorGuaranteed`,
so we have to fake it.
Invert diagnostic lints.
That is, change `diagnostic_outside_of_impl` and `untranslatable_diagnostic` from `allow` to `deny`, because more than half of the compiler has been converted to use translated diagnostics.
This commit removes more `deny` attributes than it adds `allow` attributes, which proves that this change is warranted.
r? ````@davidtwco````
That is, change `diagnostic_outside_of_impl` and
`untranslatable_diagnostic` from `allow` to `deny`, because more than
half of the compiler has be converted to use translated diagnostics.
This commit removes more `deny` attributes than it adds `allow`
attributes, which proves that this change is warranted.
Remove various `has_errors` or `err_count` uses
follow up to https://github.com/rust-lang/rust/pull/119895
r? `@nnethercote` since you recently did something similar.
There are so many more of these, but I wanted to get a PR out instead of growing the commit list indefinitely. The commits all work on their own and can be reviewed commit by commit.
Error codes are integers, but `String` is used everywhere to represent
them. Gross!
This commit introduces `ErrCode`, an integral newtype for error codes,
replacing `String`. It also introduces a constant for every error code,
e.g. `E0123`, and removes the `error_code!` macro. The constants are
imported wherever used with `use rustc_errors::codes::*`.
With the old code, we have three different ways to specify an error code
at a use point:
```
error_code!(E0123) // macro call
struct_span_code_err!(dcx, span, E0123, "msg"); // bare ident arg to macro call
\#[diag(name, code = "E0123")] // string
struct Diag;
```
With the new code, they all use the `E0123` constant.
```
E0123 // constant
struct_span_code_err!(dcx, span, E0123, "msg"); // constant
\#[diag(name, code = E0123)] // constant
struct Diag;
```
The commit also changes the structure of the error code definitions:
- `rustc_error_codes` now just defines a higher-order macro listing the
used error codes and nothing else.
- Because that's now the only thing in the `rustc_error_codes` crate, I
moved it into the `lib.rs` file and removed the `error_codes.rs` file.
- `rustc_errors` uses that macro to define everything, e.g. the error
code constants and the `DIAGNOSTIC_TABLES`. This is in its new
`codes.rs` file.
Remove unused/unnecessary features
~~The bulk of the actual code changes here is replacing try blocks with equivalent closures. I'm not entirely sure that's a good idea since it may have perf impact, happy to revert if that's the case/the change is unwanted.~~
I also removed a lot of `recursion_limit = "256"` since everything seems to build fine without that and most don't have any comment justifying it.
remove StructuralEq trait
The documentation given for the trait is outdated: *all* function pointers implement `PartialEq` and `Eq` these days. So the `StructuralEq` trait doesn't really seem to have any reason to exist any more.
One side-effect of this PR is that we allow matching on some consts that do not implement `Eq`. However, we already allowed matching on floats and consts containing floats, so this is not new, it is just allowed in more cases now. IMO it makes no sense at all to allow float matching but also sometimes require an `Eq` instance. If we want to require `Eq` we should adjust https://github.com/rust-lang/rust/pull/115893 to check for `Eq`, and rule out float matching for good.
Fixes https://github.com/rust-lang/rust/issues/115881
Add `#[coverage(off)]` to closures introduced by `#[test]` and `#[bench]`
These closures are an internal implementation detail of the `#[test]` and `#[bench]` attribute macros, so from a user perspective there is no reason to instrument them for coverage.
Skipping them makes coverage reports slightly cleaner, and will also allow other changes to span processing during coverage instrumentation, without having to worry about how they affect the `#[test]` macro.
The `#[coverage(off)]` attribute has no effect when `-Cinstrument-coverage` is not used.
Fixes#120046.
---
Note that this PR has no effect on the user-written function that has the `#[test]` attribute attached to it. That function will still be instrumented as normal.
Pack u128 in the compiler to mitigate new alignment
This is based on #116672, adding a new `#[repr(packed(8))]` wrapper on `u128` to avoid changing any of the compiler's size assertions. This is needed in two places:
* `SwitchTargets`, otherwise its `SmallVec<[u128; 1]>` gets padded up to 32 bytes.
* `LitKind::Int`, so that entire `enum` can stay 24 bytes.
* This change definitely has far-reaching effects though, since it's public.
We have several methods indicating the presence of errors, lint errors,
and delayed bugs. I find it frustrating that it's very unclear which one
you should use in any particular spot. This commit attempts to instill a
basic principle of "use the least general one possible", because that
reflects reality in practice -- `has_errors` is the least general one
and has by far the most uses (esp. via `abort_if_errors`).
Specifics:
- Add some comments giving some usage guidelines.
- Prefer `has_errors` to comparing `err_count` to zero.
- Remove `has_errors_or_span_delayed_bugs` because it's a weird one: in
the cases where we need to count delayed bugs, we should really be
counting lint errors as well.
- Rename `is_compilation_going_to_fail` as
`has_errors_or_lint_errors_or_span_delayed_bugs`, for consistency with
`has_errors` and `has_errors_or_lint_errors`.
- Change a few other `has_errors_or_lint_errors` calls to `has_errors`,
as per the "least general" principle.
This didn't turn out to be as neat as I hoped when I started, but I
think it's still an improvement.
`is_force_warn` is only possible for diagnostics with `Level::Warning`,
but it is currently stored in `Diagnostic::code`, which every diagnostic
has.
This commit:
- removes the boolean `DiagnosticId::Lint::is_force_warn` field;
- adds a `ForceWarning` variant to `Level`.
Benefits:
- The common `Level::Warning` case now has no arguments, replacing
lots of `Warning(None)` occurrences.
- `rustc_session::lint::Level` and `rustc_errors::Level` are more
similar, both having `ForceWarning` and `Warning`.
In #119606 I added them and used a `_mv` suffix, but that wasn't great.
A `with_` prefix has three different existing uses.
- Constructors, e.g. `Vec::with_capacity`.
- Wrappers that provide an environment to execute some code, e.g.
`with_session_globals`.
- Consuming chaining methods, e.g. `Span::with_{lo,hi,ctxt}`.
The third case is exactly what we want, so this commit changes
`DiagnosticBuilder::foo_mv` to `DiagnosticBuilder::with_foo`.
Thanks to @compiler-errors for the suggestion.
- `struct_foo` + `emit` -> `foo`
- `create_foo` + `emit` -> `emit_foo`
I have made recent commits in other PRs that have removed some of these
shortcuts for combinations with few uses, e.g.
`struct_span_err_with_code`. But for the remaining combinations that
have high levels of use, we might as well use them wherever possible.
This works for most of its call sites. This is nice, because `emit` very
much makes sense as a consuming operation -- indeed,
`DiagnosticBuilderState` exists to ensure no diagnostic is emitted
twice, but it uses runtime checks.
For the small number of call sites where a consuming emit doesn't work,
the commit adds `DiagnosticBuilder::emit_without_consuming`. (This will
be removed in subsequent commits.)
Likewise, `emit_unless` becomes consuming. And `delay_as_bug` becomes
consuming, while `delay_as_bug_without_consuming` is added (which will
also be removed in subsequent commits.)
All this requires significant changes to `DiagnosticBuilder`'s chaining
methods. Currently `DiagnosticBuilder` method chaining uses a
non-consuming `&mut self -> &mut Self` style, which allows chaining to
be used when the chain ends in `emit()`, like so:
```
struct_err(msg).span(span).emit();
```
But it doesn't work when producing a `DiagnosticBuilder` value,
requiring this:
```
let mut err = self.struct_err(msg);
err.span(span);
err
```
This style of chaining won't work with consuming `emit` though. For
that, we need to use to a `self -> Self` style. That also would allow
`DiagnosticBuilder` production to be chained, e.g.:
```
self.struct_err(msg).span(span)
```
However, removing the `&mut self -> &mut Self` style would require that
individual modifications of a `DiagnosticBuilder` go from this:
```
err.span(span);
```
to this:
```
err = err.span(span);
```
There are *many* such places. I have a high tolerance for tedious
refactorings, but even I gave up after a long time trying to convert
them all.
Instead, this commit has it both ways: the existing `&mut self -> Self`
chaining methods are kept, and new `self -> Self` chaining methods are
added, all of which have a `_mv` suffix (short for "move"). Changes to
the existing `forward!` macro lets this happen with very little
additional boilerplate code. I chose to add the suffix to the new
chaining methods rather than the existing ones, because the number of
changes required is much smaller that way.
This doubled chainging is a bit clumsy, but I think it is worthwhile
because it allows a *lot* of good things to subsequently happen. In this
commit, there are many `mut` qualifiers removed in places where
diagnostics are emitted without being modified. In subsequent commits:
- chaining can be used more, making the code more concise;
- more use of chaining also permits the removal of redundant diagnostic
APIs like `struct_err_with_code`, which can be replaced easily with
`struct_err` + `code_mv`;
- `emit_without_diagnostic` can be removed, which simplifies a lot of
machinery, removing the need for `DiagnosticBuilderState`.
Because it's redundant w.r.t. `Diagnostic::is_lint`, which is present
for every diagnostic level.
`struct_lint_level_impl` was the only place that set the `Error` field
to `true`, and it's also the only place that calls
`Diagnostic::is_lint()` to set the `is_lint` field.
`Diagnostic` has 40 methods that return `&mut Self` and could be
considered setters. Four of them have a `set_` prefix. This doesn't seem
necessary for a type that implements the builder pattern. This commit
removes the `set_` prefixes on those four methods.
There are only three. It's simpler to make the type
`DiagnosticBuilder<'_, ()>` from the start, no matter the level, than to
change the guarantee later.
`IntoDiagnostic` defaults to `ErrorGuaranteed`, because errors are the
most common diagnostic level. It makes sense to do likewise for the
closely-related (and much more widely used) `DiagnosticBuilder` type,
letting us write `DiagnosticBuilder<'a, ErrorGuaranteed>` as just
`DiagnosticBuilder<'a>`. This cuts over 200 lines of code due to many
multi-line things becoming single line things.
Add support for `for await` loops
This adds support for `for await` loops. This includes parsing, desugaring in AST->HIR lowering, and adding some support functions to the library.
Given a loop like:
```rust
for await i in iter {
...
}
```
this is desugared to something like:
```rust
let mut iter = iter.into_async_iter();
while let Some(i) = loop {
match core::pin::Pin::new(&mut iter).poll_next(cx) {
Poll::Ready(i) => break i,
Poll::Pending => yield,
}
} {
...
}
```
This PR also adds a basic `IntoAsyncIterator` trait. This is partly for symmetry with the way `Iterator` and `IntoIterator` work. The other reason is that for async iterators it's helpful to have a place apart from the data structure being iterated over to store state. `IntoAsyncIterator` gives us a good place to do this.
I've gated this feature behind `async_for_loop` and opened #118898 as the feature tracking issue.
r? `@compiler-errors`
And make all hand-written `IntoDiagnostic` impls generic, by using
`DiagnosticBuilder::new(dcx, level, ...)` instead of e.g.
`dcx.struct_err(...)`.
This means the `create_*` functions are the source of the error level.
This change will let us remove `struct_diagnostic`.
Note: `#[rustc_lint_diagnostics]` is added to `DiagnosticBuilder::new`,
it's necessary to pass diagnostics tests now that it's used in
`into_diagnostic` functions.
It's necessary for `derive(Diagnostic)`, but is best avoided elsewhere
because there are clearer alternatives.
This required adding `Handler::struct_almost_fatal`.
`tokenstream::Spacing` appears on all `TokenTree::Token` instances,
both punct and non-punct. Its current usage:
- `Joint` means "can join with the next token *and* that token is a
punct".
- `Alone` means "cannot join with the next token *or* can join with the
next token but that token is not a punct".
The fact that `Alone` is used for two different cases is awkward.
This commit augments `tokenstream::Spacing` with a new variant
`JointHidden`, resulting in:
- `Joint` means "can join with the next token *and* that token is a
punct".
- `JointHidden` means "can join with the next token *and* that token is a
not a punct".
- `Alone` means "cannot join with the next token".
This *drastically* improves the output of `print_tts`. For example,
this:
```
stringify!(let a: Vec<u32> = vec![];)
```
currently produces this string:
```
let a : Vec < u32 > = vec! [] ;
```
With this PR, it now produces this string:
```
let a: Vec<u32> = vec![] ;
```
(The space after the `]` is because `TokenTree::Delimited` currently
doesn't have spacing information. The subsequent commit fixes this.)
The new `print_tts` doesn't replicate original code perfectly. E.g.
multiple space characters will be condensed into a single space
character. But it's much improved.
`print_tts` still produces the old, uglier output for code produced by
proc macros. Because we have to translate the generated code from
`proc_macro::Spacing` to the more expressive `token::Spacing`, which
results in too much `proc_macro::Along` usage and no
`proc_macro::JointHidden` usage. So `space_between` still exists and
is used by `print_tts` in conjunction with the `Spacing` field.
This change will also help with the removal of `Token::Interpolated`.
Currently interpolated tokens are pretty-printed nicely via AST pretty
printing. `Token::Interpolated` removal will mean they get printed with
`print_tts`. Without this change, that would result in much uglier
output for code produced by decl macro expansions. With this change, AST
pretty printing and `print_tts` produce similar results.
The commit also tweaks the comments on `proc_macro::Spacing`. In
particular, it refers to "compound tokens" rather than "multi-char
operators" because lifetimes aren't operators.
Implement `--env` compiler flag (without `tracked_env` support)
Part of https://github.com/rust-lang/rust/issues/80792.
Implementation of https://github.com/rust-lang/compiler-team/issues/653.
Not an implementation of https://github.com/rust-lang/rfcs/pull/2794.
It adds the `--env` compiler flag option which allows to set environment values used by `env!` and `option_env!`.
Important to note: When trying to retrieve an environment variable value, it will first look into the ones defined with `--env`, and if there isn't one, then only it will look into the environment variables. So if you use `--env PATH=a`, then `env!("PATH")` will return `"a"` and not the actual `PATH` value.
As mentioned in the title, `tracked_env` support is not added here. I'll do it in a follow-up PR.
r? rust-lang/compiler
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
