Suggest `let` or `==` on typo'd let-chain
When encountering a bare assignment in a let-chain, suggest turning the
assignment into a `let` expression or an equality check.
```
error: expected expression, found `let` statement
--> $DIR/bad-if-let-suggestion.rs:5:8
|
LL | if let x = 1 && i = 2 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if` and `while` expressions
help: you might have meant to continue the let-chain
|
LL | if let x = 1 && let i = 2 {}
| +++
help: you might have meant to compare for equality
|
LL | if let x = 1 && i == 2 {}
| +
```
Add `never_patterns` feature gate
This PR adds the feature gate and most basic parsing for the experimental `never_patterns` feature. See the tracking issue (https://github.com/rust-lang/rust/issues/118155) for details on the experiment.
`@scottmcm` has agreed to be my lang-team liaison for this experiment.
Remove HIR opkinds
`hir::BinOp`, `hir::BinOpKind`, and `hir::UnOp` are identical to `ast::BinOp`, `ast::BinOpKind`, and `ast::UnOp`, respectively. This seems silly, so this PR removes the HIR ones. (A re-export lets the AST ones be referred to using a `hir::` qualifier, which avoids renaming churn.)
r? `@cjgillot`
When encountering a bare assignment in a let-chain, suggest turning the
assignment into a `let` expression or an equality check.
```
error: expected expression, found `let` statement
--> $DIR/bad-if-let-suggestion.rs:5:8
|
LL | if let x = 1 && i = 2 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if` and `while` expressions
help: you might have meant to continue the let-chain
|
LL | if let x = 1 && let i = 2 {}
| +++
help: you might have meant to compare for equality
|
LL | if let x = 1 && i == 2 {}
| +
```
- Rename them both `as_str`, which is the typical name for a function
that returns a `&str`. (`to_string` is appropriate for functions
returning `String` or maybe `Cow<'a, str>`.)
- Change `UnOp::as_str` from an associated function (weird!) to a
method.
- Avoid needless `self` dereferences.
Recover `dyn` and `impl` after `for<...>`
Recover `dyn` and `impl` after `for<...>` in types. Reuses the logic for parsing bare trait objects, so it doesn't fix cases like `for<'a> dyn Trait + dyn Trait` or anything, but that seems somewhat of a different issue.
Parsing recovery logic is a bit involved, but I couldn't find a way to simplify it.
Fixes#117882
More detail when expecting expression but encountering bad macro argument
On nested macro invocations where the same macro fragment changes fragment type from one to the next, point at the chain of invocations and at the macro fragment definition place, explaining that the change has occurred.
Fix#71039.
```
error: expected expression, found pattern `1 + 1`
--> $DIR/trace_faulty_macros.rs:49:37
|
LL | (let $p:pat = $e:expr) => {test!(($p,$e))};
| ------- -- this is interpreted as expression, but it is expected to be pattern
| |
| this macro fragment matcher is expression
...
LL | (($p:pat, $e:pat)) => {let $p = $e;};
| ------ ^^ expected expression
| |
| this macro fragment matcher is pattern
...
LL | test!(let x = 1+1);
| ------------------
| | |
| | this is expected to be expression
| in this macro invocation
|
= note: when forwarding a matched fragment to another macro-by-example, matchers in the second macro will see an opaque AST of the fragment type, not the underlying tokens
= note: this error originates in the macro `test` (in Nightly builds, run with -Z macro-backtrace for more info)
```
Give a better diagnostic for missing parens in Fn* bounds
Fixes#108109
It would be nice to try and recover here, but I'm not sure it's worth the effort, especially as the bounds on the recovered function would be incorrect.
Most notably, this commit changes the `pub use crate::*;` in that file
to `use crate::*;`. This requires a lot of `use` items in other crates
to be adjusted, because everything defined within `rustc_span::*` was
also available via `rustc_span::source_map::*`, which is bizarre.
The commit also removes `SourceMap::span_to_relative_line_string`, which
is unused.
Esteban Küber