Actually use the inferred ClosureKind from signature inference in coroutine-closures

This commit is contained in:
Michael Goulet 2024-04-01 14:47:12 -04:00
parent 385fa9d845
commit 3d9d5d7c96
9 changed files with 203 additions and 60 deletions

View File

@ -227,11 +227,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
kind: TypeVariableOriginKind::ClosureSynthetic,
span: expr_span,
});
let closure_kind_ty = self.next_ty_var(TypeVariableOrigin {
// FIXME(eddyb) distinguish closure kind inference variables from the rest.
kind: TypeVariableOriginKind::ClosureSynthetic,
span: expr_span,
});
let closure_kind_ty = match expected_kind {
Some(kind) => Ty::from_closure_kind(tcx, kind),
// Create a type variable (for now) to represent the closure kind.
// It will be unified during the upvar inference phase (`upvar.rs`)
None => self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::ClosureSynthetic,
span: expr_span,
}),
};
let coroutine_captures_by_ref_ty = self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::ClosureSynthetic,
span: expr_span,
@ -262,10 +269,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
},
);
let coroutine_kind_ty = self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::ClosureSynthetic,
span: expr_span,
});
let coroutine_kind_ty = match expected_kind {
Some(kind) => Ty::from_coroutine_closure_kind(tcx, kind),
// Create a type variable (for now) to represent the closure kind.
// It will be unified during the upvar inference phase (`upvar.rs`)
None => self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::ClosureSynthetic,
span: expr_span,
}),
};
let coroutine_upvars_ty = self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::ClosureSynthetic,
span: expr_span,

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@ -399,16 +399,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
);
// Additionally, we can now constrain the coroutine's kind type.
let ty::Coroutine(_, coroutine_args) =
*self.typeck_results.borrow().expr_ty(body.value).kind()
else {
bug!();
};
self.demand_eqtype(
span,
coroutine_args.as_coroutine().kind_ty(),
Ty::from_coroutine_closure_kind(self.tcx, closure_kind),
);
//
// We only do this if `infer_kind`, because if we have constrained
// the kind from closure signature inference, the kind inferred
// for the inner coroutine may actually be more restrictive.
if infer_kind {
let ty::Coroutine(_, coroutine_args) =
*self.typeck_results.borrow().expr_ty(body.value).kind()
else {
bug!();
};
self.demand_eqtype(
span,
coroutine_args.as_coroutine().kind_ty(),
Ty::from_coroutine_closure_kind(self.tcx, closure_kind),
);
}
}
self.log_closure_min_capture_info(closure_def_id, span);

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@ -88,4 +88,38 @@ async fn async_main() {
};
call_once(c).await;
}
fn force_fnonce<T>(f: impl async FnOnce() -> T) -> impl async FnOnce() -> T {
f
}
// Capture something with `move`, but infer to `AsyncFnOnce`
{
let x = Hello(6);
let c = force_fnonce(async move || {
println!("{x:?}");
});
call_once(c).await;
let x = &Hello(7);
let c = force_fnonce(async move || {
println!("{x:?}");
});
call_once(c).await;
}
// Capture something by-ref, but infer to `AsyncFnOnce`
{
let x = Hello(8);
let c = force_fnonce(async || {
println!("{x:?}");
});
call_once(c).await;
let x = &Hello(9);
let c = force_fnonce(async || {
println!("{x:?}");
});
call_once(c).await;
}
}

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@ -0,0 +1,31 @@
error[E0597]: `x` does not live long enough
--> $DIR/async-closure-captures.rs:LL:CC
|
LL | let c = force_fnonce(async move || {
| ____________________________________________-
LL | | println!("{x:?}");
| | ^ borrowed value does not live long enough
LL | | });
| | --
| | ||
| | |`x` dropped here while still borrowed
| |_________|borrow later used here
| value captured here by coroutine
error[E0597]: `x` does not live long enough
--> $DIR/async-closure-captures.rs:LL:CC
|
LL | let c = force_fnonce(async move || {
| ____________________________________________-
LL | | println!("{x:?}");
| | ^ borrowed value does not live long enough
LL | | });
| | --
| | ||
| | |`x` dropped here while still borrowed
| |_________|borrow later used here
| value captured here by coroutine
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0597`.

View File

@ -1,10 +0,0 @@
Hello(0)
Hello(0)
Hello(1)
Hello(1)
Hello(2)
Hello(3)
Hello(3)
Hello(4)
Hello(4)
Hello(5)

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@ -1,7 +1,7 @@
//@ aux-build:block-on.rs
//@ edition:2021
//@ run-pass
//@ check-run-results
// Same as miri's `tests/pass/async-closure-captures.rs`, keep in sync
@ -79,4 +79,40 @@ async fn async_main() {
};
call_once(c).await;
}
fn force_fnonce<T>(f: impl async FnOnce() -> T) -> impl async FnOnce() -> T {
f
}
// Capture something with `move`, but infer to `AsyncFnOnce`
{
let x = Hello(6);
let c = force_fnonce(async move || {
println!("{x:?}");
});
call_once(c).await;
let x = &Hello(7);
let c = force_fnonce(async move || {
println!("{x:?}");
});
call_once(c).await;
}
// Capture something by-ref, but infer to `AsyncFnOnce`
{
let x = Hello(8);
let c = force_fnonce(async || {
println!("{x:?}");
//~^ ERROR `x` does not live long enough
});
call_once(c).await;
let x = &Hello(9);
let c = force_fnonce(async || {
println!("{x:?}");
//~^ ERROR `x` does not live long enough
});
call_once(c).await;
}
}

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@ -0,0 +1,31 @@
error[E0597]: `x` does not live long enough
--> $DIR/captures.rs:89:24
|
LL | let c = force_fnonce(async move || {
| ____________________________________________-
LL | | println!("{x:?}");
| | ^ borrowed value does not live long enough
LL | | });
| | --
| | ||
| | |`x` dropped here while still borrowed
| |_________|borrow later used here
| value captured here by coroutine
error[E0597]: `x` does not live long enough
--> $DIR/captures.rs:95:24
|
LL | let c = force_fnonce(async move || {
| ____________________________________________-
LL | | println!("{x:?}");
| | ^ borrowed value does not live long enough
LL | | });
| | --
| | ||
| | |`x` dropped here while still borrowed
| |_________|borrow later used here
| value captured here by coroutine
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0597`.

View File

@ -2,18 +2,22 @@
#![feature(async_closure)]
fn main() {
fn needs_async_fn(_: impl async Fn()) {}
fn needs_async_fn(_: impl async Fn()) {}
fn a() {
let mut x = 1;
needs_async_fn(async || {
//~^ ERROR expected a closure that implements the `async Fn` trait, but this closure only implements `async FnMut`
//~^ ERROR cannot borrow `x` as mutable, as it is a captured variable in a `Fn` closure
x += 1;
});
}
fn b() {
let x = String::new();
needs_async_fn(move || async move {
//~^ ERROR expected a closure that implements the `async Fn` trait, but this closure only implements `async FnOnce`
println!("{x}");
});
}
fn main() {}

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@ -1,26 +1,5 @@
error[E0525]: expected a closure that implements the `async Fn` trait, but this closure only implements `async FnMut`
--> $DIR/wrong-fn-kind.rs:9:20
|
LL | needs_async_fn(async || {
| -------------- -^^^^^^^
| | |
| _____|______________this closure implements `async FnMut`, not `async Fn`
| | |
| | required by a bound introduced by this call
LL | |
LL | | x += 1;
| | - closure is `async FnMut` because it mutates the variable `x` here
LL | | });
| |_____- the requirement to implement `async Fn` derives from here
|
note: required by a bound in `needs_async_fn`
--> $DIR/wrong-fn-kind.rs:6:31
|
LL | fn needs_async_fn(_: impl async Fn()) {}
| ^^^^^^^^^^ required by this bound in `needs_async_fn`
error[E0525]: expected a closure that implements the `async Fn` trait, but this closure only implements `async FnOnce`
--> $DIR/wrong-fn-kind.rs:15:20
--> $DIR/wrong-fn-kind.rs:17:20
|
LL | needs_async_fn(move || async move {
| -------------- -^^^^^^
@ -35,11 +14,29 @@ LL | | });
| |_____- the requirement to implement `async Fn` derives from here
|
note: required by a bound in `needs_async_fn`
--> $DIR/wrong-fn-kind.rs:6:31
--> $DIR/wrong-fn-kind.rs:5:27
|
LL | fn needs_async_fn(_: impl async Fn()) {}
| ^^^^^^^^^^ required by this bound in `needs_async_fn`
LL | fn needs_async_fn(_: impl async Fn()) {}
| ^^^^^^^^^^ required by this bound in `needs_async_fn`
error[E0596]: cannot borrow `x` as mutable, as it is a captured variable in a `Fn` closure
--> $DIR/wrong-fn-kind.rs:9:29
|
LL | fn needs_async_fn(_: impl async Fn()) {}
| --------------- change this to accept `FnMut` instead of `Fn`
...
LL | needs_async_fn(async || {
| _____--------------_--------_^
| | | |
| | | in this closure
| | expects `Fn` instead of `FnMut`
LL | |
LL | | x += 1;
| | - mutable borrow occurs due to use of `x` in closure
LL | | });
| |_____^ cannot borrow as mutable
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0525`.
Some errors have detailed explanations: E0525, E0596.
For more information about an error, try `rustc --explain E0525`.