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.
Propagate spans and attributes from proc macro definitions
Thanks to https://github.com/rust-lang/rust/pull/63269 we now have spans and attributes from proc macro definitions available in metadata.
However, that PR didn't actually put them into use! This PR finishes that work.
Attributes `rustc_macro_transparency`, `allow_internal_unstable`, `allow_internal_unsafe`, `local_inner_macros`, `rustc_builtin_macro`, `stable`, `unstable`, `rustc_deprecated`, `deprecated` now have effect when applied to proc macro definition functions.
From those attributes only `deprecated` is both stable and supposed to be used in new code.
(`#![staged_api]` still cannot be used in proc macro crates for unrelated reasons though.)
`Span::def_site` from the proc macro API now returns the correct location of the proc macro definition.
Also, I made a mistake in https://github.com/rust-lang/rust/pull/63269#discussion_r312702919, loaded proc macros didn't actually use the resolver cache.
This PR fixes the caching issue, now proc macros go through the `Resolver::macro_map` cache as well.
(Also, the first commit turns `proc_macro::quote` into a regular built-in macro to reduce the number of places where `SyntaxExtension`s need to be manually created.)
Fully implement or-pattern parsing
Builds upon the initial parsing in https://github.com/rust-lang/rust/pull/61708 to fully implement or-pattern (`p | q`) parsing as specified in [the grammar section of RFC 2535](https://github.com/rust-lang/rfcs/blob/master/text/2535-or-patterns.md#grammar).
Noteworthy:
- We allow or-patterns in `[p | q, ...]`.
- We allow or-patterns in `let` statements and `for` expressions including with leading `|`.
- We improve recovery for `p || q` (+ tests for that in `multiple-pattern-typo.rs`).
- We improve recovery for `| p | q` in inner patterns (tests in `or-patterns-syntactic-fail.rs`).
- We rigorously test or-pattern parsing (in `or-patterns-syntactic-{pass,fail}.rs`).
- We harden the feature gating tests.
- We do **_not_** change `ast.rs`. That is, `ExprKind::Let.0` and `Arm.pats` still accept `Vec<P<Pat>>`.
I was starting work on that but it would be cleaner to do this in a separate PR so this one has a narrower scope.
cc @dlrobertson
cc the tracking issue https://github.com/rust-lang/rust/issues/54883.
r? @estebank
Point at method call on missing annotation error
Make it clearer where the type name that couldn't be inferred comes from.
Before:
```
error[E0282]: type annotations needed
--> src/test/ui/span/type-annotations-needed-expr.rs:2:13
|
2 | let _ = (vec![1,2,3]).into_iter().sum() as f64; //~ ERROR E0282
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for `S`
|
= note: type must be known at this point
```
after
```
error[E0282]: type annotations needed
--> src/test/ui/span/type-annotations-needed-expr.rs:2:39
|
2 | let _ = (vec![1,2,3]).into_iter().sum() as f64; //~ ERROR E0282
| ^^^ cannot infer type for `S`
|
= note: type must be known at this point
```
CC #63852.
Suggest calling closure with resolved return type when appropriate
Follow up to #63337. CC #63100.
```
error[E0308]: mismatched types
--> $DIR/fn-or-tuple-struct-without-args.rs:46:20
|
LL | let closure = || 42;
| -- closure defined here
LL | let _: usize = closure;
| ^^^^^^^
| |
| expected usize, found closure
| help: use parentheses to call this closure: `closure()`
|
= note: expected type `usize`
found type `[closure@$DIR/fn-or-tuple-struct-without-args.rs:45:19: 45:24]`
```
