[wg-async-await] Drop `async fn` arguments in async block
Fixes#54716.
This PR modifies the HIR lowering (and some other places to make this work) so that unused arguments to a async function are always dropped inside the async move block and not at the end of the function body.
```
async fn foo(<pattern>: <type>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>) {
async move {
let <pattern>: <ty> = __arg0;
} // <-- dropped as you "exit" the async block
}
```
However, the exact ordering of drops is not the same as a regular function, [as visible in this playground example](https://play.rust-lang.org/?version=stable&mode=debug&edition=2015&gist=be39af1a58e5d430be1eb3c722cb1ec3) - I believe this to be an unrelated issue. There is a [Zulip topic](https://rust-lang.zulipchat.com/#narrow/stream/187312-t-compiler.2Fwg-async-await/topic/.2354716.20drop.20order) for this.
r? @cramertj
cc @nikomatsakis
This commit introduces an `ArgSource` enum that is lowered into the HIR
so that diagnostics can correctly refer to the argument pattern's
original name rather than the generated pattern.
This avoids issues with `impl_trait_in_bindings` as the type from the
argument is normally used as the let binding, but `impl Trait` is
unstable in binding position.
This commit adds an `AsyncArgument` struct to the AST that contains the
generated argument and statement that will be used in HIR lowering, name
resolution and def collection.
Remove mutability from `Def::Static`
Querify `TyCtxt::is_static`.
Use `Mutability` instead of bool in foreign statics in AST/HIR.
cc https://github.com/rust-lang/rust/pull/60110
r? @eddyb
This will be used to keep track of the origin of a local in the AST. In
particular, it will be used by `async fn` lowering for the locals in
`let <pat>: <ty> = __arg0;` statements.
Fix fn front matter parsing ICE from invalid code.
Fixes#60075.
This PR fixes an "unreachable code" ICE that results from parsing
invalid code where the compiler is expecting the next trait item
declaration in the middle of the previous trait item due to extra
closing braces.
r? @estebank (thanks for the minimized test case)
This commit fixes an "unreachable code" ICE that results from parsing
invalid code where the compiler is expecting the next trait item
declaration in the middle of the previous trait item due to extra
closing braces.
Recover from missing semicolon based on the found token
When encountering one of a few keywords when a semicolon was
expected, suggest the semicolon and recover:
```
error: expected one of `.`, `;`, `?`, or an operator, found `let`
--> $DIR/recover-missing-semi.rs:4:5
|
LL | let _: usize = ()
| - help: missing semicolon here
LL |
LL | let _ = 3;
| ^^^
error[E0308]: mismatched types
--> $DIR/recover-missing-semi.rs:2:20
|
LL | let _: usize = ()
| ^^ expected usize, found ()
|
= note: expected type `usize`
found type `()`
```
When encountering one of a few keywords when a semicolon was
expected, suggest the semicolon and recover:
```
error: expected one of `.`, `;`, `?`, or an operator, found `let`
--> $DIR/recover-missing-semi.rs:4:5
|
LL | let _: usize = ()
| - help: missing semicolon here
LL |
LL | let _ = 3;
| ^^^
error[E0308]: mismatched types
--> $DIR/recover-missing-semi.rs:2:20
|
LL | let _: usize = ()
| ^^ expected usize, found ()
|
= note: expected type `usize`
found type `()`
```
Do not complain about unmentioned fields in recovered patterns
When the parser has to recover from malformed code in a pattern, do not
complain about missing fields.
Fix#59145.
This commit makes two changes - separating the `NodeId` that identifies
an enum variant from the `NodeId` that identifies the variant's
constructor; and no longer creating a `NodeId` for `Struct`-style enum
variants and structs.
Separation of the variant id and variant constructor id will allow the
rest of RFC 2008 to be implemented by lowering the visibility of the
variant's constructor without lowering the visbility of the variant
itself.
No longer creating a `NodeId` for `Struct`-style enum variants and
structs mostly simplifies logic as previously this `NodeId` wasn't used.
There were various cases where the `NodeId` wouldn't be used unless
there was an unit or tuple struct or enum variant but not all uses of
this `NodeId` had that condition, by removing this `NodeId`, this must
be explicitly dealt with. This change mostly applied cleanly, but there
were one or two cases in name resolution and one case in type check
where the existing logic required a id for `Struct`-style enum variants
and structs.
Do not complain about non-existing fields after parse recovery
When failing to parse struct-like enum variants, the ADT gets recorded
as having no fields. Record that we have actually recovered during
parsing of this variant to avoid complaing about non-existing fields
when actually using it.
Fix#57361.
