Rename `${length()}` to `${len()}`
Implements the rename suggested in https://github.com/rust-lang/rust/pull/122808#issuecomment-2047722187
> I brought this up in the doc PR but it belongs here – `length` should probably be renamed `len` before stabilization. The latter is de facto standard in the standard library, whereas the former is only used in a single unstable API. These metafunctions aren’t library items of course, but should presumably still be consistent with established names.
r? `@c410-f3r`
The extra span is now recorded in the new `TokenKind::NtIdent` and
`TokenKind::NtLifetime`. These both consist of a single token, and so
there's no operator precedence problems with inserting them directly
into the token stream.
The other way to do this would be to wrap the ident/lifetime in invisible
delimiters, but there's a lot of code that assumes an interpolated
ident/lifetime fits in a single token, and changing all that code to work with
invisible delimiters would have been a pain. (Maybe it could be done in a
follow-up.)
This change might not seem like much of a win, but it's a first step toward the
much bigger and long-desired removal of `Nonterminal` and
`TokenKind::Interpolated`. That change is big and complex enough that it's
worth doing this piece separately. (Indeed, this commit is based on part of a
late commit in #114647, a prior attempt at that big and complex change.)
This span records the declaration of the metavariable in the LHS of the macro.
It's used in a couple of error messages. Unfortunately, it gets in the way of
the long-term goal of removing `TokenKind::Interpolated`. So this commit
removes it, which degrades a couple of (obscure) error messages but makes
things simpler and enables the next commit.
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.
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.
There are some test cases involving `parse` and `tokenstream` and
`mut_visit` that are located in `rustc_expand`. Because it used to be
the case that constructing a `ParseSess` required the involvement of
`rustc_expand`. However, since #64197 merged (a long time ago)
`rust_expand` no longer needs to be involved.
This commit moves the tests into `rustc_parse`. This is the optimal
place for the `parse` tests. It's not ideal for the `tokenstream` and
`mut_visit` tests -- they would be better in `rustc_ast` -- but they
still rely on parsing, which is not available in `rustc_ast`. But
`rustc_parse` is lower down in the crate graph and closer to `rustc_ast`
than `rust_expand`, so it's still an improvement for them.
The exact renaming is as follows:
- rustc_expand/src/mut_visit/tests.rs -> rustc_parse/src/parser/mut_visit/tests.rs
- rustc_expand/src/tokenstream/tests.rs -> rustc_parse/src/parser/tokenstream/tests.rs
- rustc_expand/src/tests.rs + rustc_expand/src/parse/tests.rs ->
compiler/rustc_parse/src/parser/tests.rs
The latter two test files are combined because there's no need for them
to be separate, and having a `rustc_parse::parser::parse` module would
be weird. This also means some `pub(crate)`s can be removed.
It is currently an enum and the `tts` and `idx` fields are repeated
across the two variants.
This commit splits it into a struct `Frame` and an enum `FrameKind`, to
factor out the duplication. The commit also renames `Frame::new` as
`Frame::new_delimited` and adds `Frame::new_sequence`. I.e. both
variants now have a constructor.
Control flow never gets past the end of the `ExpandResult::Retry` match
arm, due to the `span_bug` and the `continue`. Therefore, the code after
the match can only be reached from the `ExpandResult::Ready` arm.
This commit moves that code after the match into the
`ExpandResult::Ready` arm, avoiding the need for the `continue` in the
`ExpandResult::Retry` arm.
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)`.
`-Z debug-macros` is "stabilized" by enabling it by default and removing.
`-Z collapse-macro-debuginfo` is stabilized as `-C collapse-macro-debuginfo`.
It now supports all typical boolean values (`parse_opt_bool`) in addition to just yes/no.
Default value of `collapse_debuginfo` was changed from `false` to `external` (i.e. collapsed if external, not collapsed if local).
`#[collapse_debuginfo]` attribute without a value is no longer supported to avoid guessing the default.
Cleanup: Rename `ModSep` to `PathSep`
`::` is usually referred to as the *path separator* (citation needed).
The existing name `ModSep` for *module separator* is a bit misleading since it in fact separates the segments of arbitrary path segments, not only ones resolving to modules. Let me just give a shout-out to associated items (`T::Assoc`, `<Ty as Trait>::function`) and enum variants (`Option::None`).
Motivation: Reduce friction for new contributors, prevent potential confusion.
cc `@petrochenkov`
r? nnethercote or compiler
Avoid expanding to unstable internal method
Fixes#123156
Rather than expanding to `std::rt::begin_panic`, the expansion is now to `unreachable!()`. The resulting behavior is identical. A test that previously triggered the same error as #123156 has been added to ensure it does not regress.
r? compiler
warning: this argument is a mutable reference, but not used mutably
--> compiler\rustc_session\src\config.rs:2013:16
|
2013 | early_dcx: &mut EarlyDiagCtxt,
| ^^^^^^^^^^^^^^^^^^ help: consider changing to: `&EarlyDiagCtxt`
|
= 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_ast_passes\src\ast_validation.rs:1555:11
|
1555 | this: &mut AstValidator<'_>,
| ^^^^^^^^^^^^^^^^^^^^^ help: consider changing to: `&AstValidator<'_>`
|
= 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_infer\src\infer\snapshot\fudge.rs:16:12
|
16 | table: &mut UnificationTable<'_, 'tcx, T>,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider changing to: `&UnificationTable<'_, 'tcx, T>`
|
= 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_expand\src\expand.rs:961:13
|
961 | parser: &mut Parser<'a>,
| ^^^^^^^^^^^^^^^ help: consider changing to: `&Parser<'a>`
|
= warning: changing this function will impact semver compatibility
= 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
Interpolated cleanups
Various cleanups I made while working on attempts to remove `Interpolated`, that are worth merging now. Best reviewed one commit at a time.
r? `@petrochenkov`
This commit combines `MatchedTokenTree` and `MatchedNonterminal`, which
are often considered together, into a single `MatchedSingle`. It shares
a representation with the newly-parameterized `ParseNtResult`.
This will also make things much simpler if/when variants from
`Interpolated` start being moved to `ParseNtResult`.
