Fix async desugaring providing wrong input to procedural macros.
Fixes#60674.
This PR fixes a minor oversight introduced by #60535 where unused `mut` binding modes were removed from the arguments to an `async fn` (as they were added to the statement that we insert into the closure body). However, this meant that the input to procedural macros was incorrect. This removes that and instead fixes the `unused_mut` error that it avoided.
r? @cramertj
cc @taiki-e
Identify when a stmt could have been parsed as an expr
There are some expressions that can be parsed as a statement without
a trailing semicolon depending on the context, which can lead to
confusing errors due to the same looking code being accepted in some
places and not others. Identify these cases and suggest enclosing in
parenthesis making the parse non-ambiguous without changing the
accepted grammar.
Fix#54186, cc #54482, fix#59975, fix#47287.
This commit removes the modification of the mutability of simple
bindings. While the mutability isn't used, it is important that it is
kept so that the input to procedural macros matches what the user wrote.
This commit also modifies the span of the binding mode so that it is
considered a compiler desugaring and won't be linted against for being
unused..
Adds support for .await under the existing async_await feature gate.
Moves macro-like await! syntax to the await_macro feature gate.
Removes support for `await` as a non-keyword under the `async_await`
feature.
Account for paths in incorrect pub qualifier help
Handle case where incorrect pub qualifier with a mod path is used and provide the same help given for all other incorrect qualifiers by making the `pub(crate)` parse check more specific.
Ensure that drop order of `async fn` matches `fn` and that users cannot refer to generated arguments.
Fixes#60236 and fixes#60438.
This PR modifies the lowering of `async fn` arguments so that the
drop order matches the equivalent `fn`.
Previously, async function arguments were lowered as shown below:
async fn foo(<pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>) {
async move {
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
After this PR, async function arguments will be lowered as:
async fn foo(<pattern>: <ty>, <pattern>: <ty>, <pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>, __arg1: <ty>, __arg2: <ty>) {
async move {
let __arg2 = __arg2;
let <pattern> = __arg2;
let __arg1 = __arg1;
let <pattern> = __arg1;
let __arg0 = __arg0;
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
If `<pattern>` is a simple ident, then it is lowered to a single
`let <pattern> = <pattern>;` statement as an optimization.
This PR also stops users from referring to the generated `__argN`
identifiers.
r? @nikomatsakis
This commit gensyms the generated ident for replacement arguments so
that users cannot refer to them. It also ensures that levenshtein
distance suggestions do not suggest gensymed identifiers.
This commit modifies the lowering of `async fn` arguments so that the
drop order matches the equivalent `fn`.
Previously, async function arguments were lowered as shown below:
async fn foo(<pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>) {
async move {
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
After this PR, async function arguments will be lowered as:
async fn foo(<pattern>: <ty>, <pattern>: <ty>, <pattern>: <ty>) {
async move {
}
} // <-- dropped as you "exit" the fn
// ...becomes...
fn foo(__arg0: <ty>, __arg1: <ty>, __arg2: <ty>) {
async move {
let __arg2 = __arg2;
let <pattern> = __arg2;
let __arg1 = __arg1;
let <pattern> = __arg1;
let __arg0 = __arg0;
let <pattern> = __arg0;
} // <-- dropped as you "exit" the async block
}
If `<pattern>` is a simple ident, then it is lowered to a single
`let <pattern> = <pattern>;` statement as an optimization.
There are some expressions that can be parsed as a statement without
a trailing semicolon depending on the context, which can lead to
confusing errors due to the same looking code being accepted in some
places and not others. Identify these cases and suggest enclosing in
parenthesis making the parse non-ambiguous without changing the
accepted grammar.
Temporarily accept [i|u][32|size] suffixes on a tuple index and warn
Fix#60138.
#59553 will need to be kept open to track the change back to rejecting this code a few versions down thee line.
[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 `()`
```
