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`
They're identical to the same-named types from `ast`. I find it silly
(and inefficient) to have all this boilerplate code to convert one type
to an identical type.
There is already a small amount of type sharing between the AST and HIR,
e.g. `Attribute`, `MacroDef`.
The commit adds a `pub use` to `rustc_hir` so that, for example,
`ast::BinOp` can also be referred to as `hir::BinOp`. This is so the
many existing `hir`-qualified mentions of these types don't need to
change.
The commit also moves a couple of operations from the (removed) HIR
types to the AST types, e.g. `is_by_value`.
- 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.
By default, `newtype_index!` types get a default `Encodable`/`Decodable`
impl. You can opt out of this with `custom_encodable`. Opting out is the
opposite to how Rust normally works with autogenerated (derived) impls.
This commit inverts the behaviour, replacing `custom_encodable` with
`encodable` which opts into the default `Encodable`/`Decodable` impl.
Only 23 of the 59 `newtype_index!` occurrences need `encodable`.
Even better, there were eight crates with a dependency on
`rustc_serialize` just from unused default `Encodable`/`Decodable`
impls. This commit removes that dependency from those eight crates.
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)
```
- Sort dependencies and features sections.
- Add `tidy` markers to the sorted sections so they stay sorted.
- Remove empty `[lib`] sections.
- Remove "See more keys..." comments.
Excluded files:
- rustc_codegen_{cranelift,gcc}, because they're external.
- rustc_lexer, because it has external use.
- stable_mir, because it has external use.
Implement `gen` blocks in the 2024 edition
Coroutines tracking issue https://github.com/rust-lang/rust/issues/43122
`gen` block tracking issue https://github.com/rust-lang/rust/issues/117078
This PR implements `gen` blocks that implement `Iterator`. Most of the logic with `async` blocks is shared, and thus I renamed various types that were referring to `async` specifically.
An example usage of `gen` blocks is
```rust
fn foo() -> impl Iterator<Item = i32> {
gen {
yield 42;
for i in 5..18 {
if i.is_even() { continue }
yield i * 2;
}
}
}
```
The limitations (to be resolved) of the implementation are listed in the tracking issue
Format all the let-chains in compiler crates
Since rust-lang/rustfmt#5910 has landed, soon we will have support for formatting let-chains (as soon as rustfmt syncs and beta gets bumped).
This PR applies the changes [from master rustfmt to rust-lang/rust eagerly](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/out.20formatting.20of.20prs/near/374997516), so that the next beta bump does not have to deal with a 200+ file diff and can remain concerned with other things like `cfg(bootstrap)` -- #113637 was a pain to land, for example, because of let-else.
I will also add this commit to the ignore list after it has landed.
The commands that were run -- I'm not great at bash-foo, but this applies rustfmt to every compiler crate, and then reverts the two crates that should probably be formatted out-of-tree.
```
~/rustfmt $ ls -1d ~/rust/compiler/* | xargs -I@ cargo run --bin rustfmt -- `@/src/lib.rs` --config-path ~/rust --edition=2021 # format all of the compiler crates
~/rust $ git checkout HEAD -- compiler/rustc_codegen_{gcc,cranelift} # revert changes to cg-gcc and cg-clif
```
cc `@rust-lang/rustfmt`
r? `@WaffleLapkin` or `@Nilstrieb` who said they may be able to review this purely mechanical PR :>
cc `@Mark-Simulacrum` and `@petrochenkov,` who had some thoughts on the order of operations with big formatting changes in https://github.com/rust-lang/rust/pull/95262#issue-1178993801. I think the situation has changed since then, given that let-chains support exists on master rustfmt now, and I'm fairly confident that this formatting PR should land even if *bootstrap* rustfmt doesn't yet format let-chains in order to lessen the burden of the next beta bump.
`#[diagnostic::on_unimplemented]` without filters
This commit adds support for a `#[diagnostic::on_unimplemented]` attribute with the following options:
* `message` to customize the primary error message
* `note` to add a customized note message to an error message
* `label` to customize the label part of the error message
The relevant behavior is specified in [RFC-3366](https://rust-lang.github.io/rfcs/3366-diagnostic-attribute-namespace.html)
This commit adds support for a `#[diagnostic::on_unimplemented]`
attribute with the following options:
* `message` to customize the primary error message
* `note` to add a customized note message to an error message
* `label` to customize the label part of the error message
Co-authored-by: León Orell Valerian Liehr <me@fmease.dev>
Co-authored-by: Michael Goulet <michael@errs.io>
There was an incomplete version of the check in parsing and a second
version in AST validation. This meant that some, but not all, invalid
uses were allowed inside macros/disabled cfgs. It also means that later
passes have a hard time knowing when the let expression is in a valid
location, sometimes causing ICEs.
- Add a field to ExprKind::Let in AST/HIR to mark whether it's in a
valid location.
- Suppress later errors and MIR construction for invalid let
expressions.
