Use hygiene for AST passes
AST passes are now able to have resolve consider their expansions as if they were opaque macros defined either in some module in the current crate, or a fake empty module with `#[no_implicit_prelude]`.
* Add an ExpnKind for AST passes.
* Remove gensyms in AST passes.
* Remove gensyms in`#[test]`, `#[bench]` and `#[test_case]`.
* Allow opaque macros to define tests.
* Move tests for unit tests to their own directory.
* Remove `Ident::{gensym, is_gensymed}` - `Ident::gensym_if_underscore` still exists.
cc #60869, #61019
r? @petrochenkov
And remove the `unsafe` blocks, they're not necessary.
Also rewrite `InternedString::{with,with2}` to use the new functions.
Finally, add some comments about the speed of the
`as_str()`/`as_interned_str()` functions.
This allows lints and other diagnostics to refer to items
by a unique ID instead of relying on whacky path
resolution schemes that may break when items are
relocated.
Recover `mut $pat` and other improvements
- Recover on e.g. `mut Foo(x, y)` and suggest `Foo(mut x, mut y)`. Fixes https://github.com/rust-lang/rust/issues/63764.
- Recover on e.g. `let mut mut x;`
- Recover on e.g. `let keyword` and `let keyword(...)`.
- Cleanups in `token.rs` with `fn is_non_raw_ident_where` and friends.
Initial implementation of or-patterns
An incomplete implementation of or-patterns (e.g. `Some(0 | 1)` as a pattern). This patch set aims to implement initial parsing of `or-patterns`.
Related to: #54883
CC @alexreg @varkor
r? @Centril
Most `Ident`s are serialized as `InternedString`s the exceptions are:
* Reexports
* Attributes
* Idents in macro definitions
Using gensyms helped reexports emulate hygiene. However, the actual item
wouldn't have a gensymmed name so would be usable cross-crate. So
removing this case until we have proper cross-crate hygiene seems
sensible.
Codegen attributes (`inline`, `export_name`) are resolved by their
`Symbol`. This meant that opaque macro-expanded codegen attributes could
cause linker errors. This prevented making built-in derives hygienic.
Change opaque type syntax from `existential type` to type alias `impl Trait`
This implements a new feature gate `type_alias_impl_trait` (this is slightly different from the originally proposed feature name, but matches what has been used in discussion since), deprecating the old `existential_types` feature.
The syntax for opaque types has been changed. In addition, the "existential" terminology has been replaced with "opaque", as per previous discussion and the RFC.
This makes partial progress towards implementing https://github.com/rust-lang/rust/issues/63063.
r? @Centril
resolve: Improve candidate search for unresolved macro suggestions
Use same scope visiting machinery for both collecting suggestion candidates and actually resolving the names.
The PR is better read in per-commit fashion with whitespace changes ignored (the first commit in particular moves some code around).
This should be the last pre-requisite for https://github.com/rust-lang/rust/pull/62086.
r? @davidtwco
Creating a fresh expansion and immediately generating a span from it is the most common scenario.
Also avoid allocating `allow_internal_unstable` lists for derive markers repeatedly.
And rename `ExpnInfo::with_unstable` to `ExpnInfo::allow_unstable`, seems to be a better fitting name.
rustdoc: set cfg(doctest) when collecting doctests
Note: This PR builds on top of https://github.com/rust-lang/rust/pull/61199; only the last commit is specific to this PR.
As discussed in https://github.com/rust-lang/rust/pull/61199, we want the ability to isolate items to only when rustdoc is collecting doctests, but we can't use `cfg(test)` because of libcore's `#![cfg(not(test))]`. This PR proposes a new cfg flag, `cfg(doctest)`, specific to this situation, rather than reusing an existing flag. I've isolated it behind a feature gate so that we can contain the effects to nightly only. (A stable workaround that can be used in lieu of `#[cfg(doctest)]` is `#[cfg(rustdoc)] #[doc(hidden)]`, at least once https://github.com/rust-lang/rust/pull/61351 lands.)
Tracking issue: https://github.com/rust-lang/rust/issues/62210
Implement another internal lints
cc #49509
This adds ~~two~~ one internal lint~~s~~:
1. LINT_PASS_IMPL_WITHOUT_MACRO: Make sure, that the `{declare,impl}_lint_pass` macro is used to implement lint passes. cc #59669
2. ~~USAGE_OF_TYCTXT_AND_SPAN_ARGS: item 2 on the list in #49509~~
~~With 2. I wasn't sure, if this lint should be applied everywhere. That means a careful review of 0955835 would be great. Also 73fb9b4 allows this lint on some functions. Should I also apply this lint there?~~
TODO (not directly relevant for review):
- [ ] https://github.com/rust-lang/rust/pull/59316#discussion_r280186517 (not sure yet, if this works or how to query for `rustc_private`, since it's not in [`Features`](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/feature_gate/struct.Features.html) 🤔 cc @eddyb)
- [x] https://github.com/rust-lang/rust/pull/61735#discussion_r292389870
- [x] Check explicitly for the `{declare,impl}_lint_pass!` macros
r? @oli-obk
