diff options
| -rw-r--r-- | compiler/rustc_hir_typeck/src/closure.rs | 32 | ||||
| -rw-r--r-- | compiler/rustc_hir_typeck/src/upvar.rs | 50 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/coroutine/by_move_body.rs | 20 | ||||
| -rw-r--r-- | src/tools/miri/tests/pass/async-closure-captures.rs | 34 | ||||
| -rw-r--r-- | src/tools/miri/tests/pass/async-closure-captures.stdout | 4 | ||||
| -rw-r--r-- | tests/ui/async-await/async-closures/captures.rs | 34 | ||||
| -rw-r--r-- | tests/ui/async-await/async-closures/captures.run.stdout | 4 | ||||
| -rw-r--r-- | tests/ui/async-await/async-closures/wrong-fn-kind.rs | 10 | ||||
| -rw-r--r-- | tests/ui/async-await/async-closures/wrong-fn-kind.stderr | 49 |
9 files changed, 182 insertions, 55 deletions
diff --git a/compiler/rustc_hir_typeck/src/closure.rs b/compiler/rustc_hir_typeck/src/closure.rs index 36af5394015..dbae8bfb542 100644 --- a/compiler/rustc_hir_typeck/src/closure.rs +++ b/compiler/rustc_hir_typeck/src/closure.rs @@ -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, diff --git a/compiler/rustc_hir_typeck/src/upvar.rs b/compiler/rustc_hir_typeck/src/upvar.rs index 72e5b1ed95b..c987bfb9a0e 100644 --- a/compiler/rustc_hir_typeck/src/upvar.rs +++ b/compiler/rustc_hir_typeck/src/upvar.rs @@ -166,7 +166,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { span: Span, body_id: hir::BodyId, body: &'tcx hir::Body<'tcx>, - capture_clause: hir::CaptureBy, + mut capture_clause: hir::CaptureBy, ) { // Extract the type of the closure. let ty = self.node_ty(closure_hir_id); @@ -259,6 +259,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { ) .consume_body(body); + // If a coroutine is comes from a coroutine-closure that is `move`, but + // the coroutine-closure was inferred to be `FnOnce` during signature + // inference, then it's still possible that we try to borrow upvars from + // the coroutine-closure because they are not used by the coroutine body + // in a way that forces a move. + // + // This would lead to an impossible to satisfy situation, since `AsyncFnOnce` + // coroutine bodies can't borrow from their parent closure. To fix this, + // we force the inner coroutine to also be `move`. This only matters for + // coroutine-closures that are `move` since otherwise they themselves will + // be borrowing from the outer environment, so there's no self-borrows occuring. + if let UpvarArgs::Coroutine(..) = args + && let hir::CoroutineKind::Desugared(_, hir::CoroutineSource::Closure) = + self.tcx.coroutine_kind(closure_def_id).expect("coroutine should have kind") + && let parent_hir_id = + self.tcx.local_def_id_to_hir_id(self.tcx.local_parent(closure_def_id)) + && let parent_ty = self.node_ty(parent_hir_id) + && let Some(ty::ClosureKind::FnOnce) = self.closure_kind(parent_ty) + { + capture_clause = self.tcx.hir_node(parent_hir_id).expect_closure().capture_clause; + } + debug!( "For closure={:?}, capture_information={:#?}", closure_def_id, delegate.capture_information @@ -399,16 +421,22 @@ 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); diff --git a/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs b/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs index 0866205dfd0..de43f9faff9 100644 --- a/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs +++ b/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs @@ -91,15 +91,17 @@ impl<'tcx> MirPass<'tcx> for ByMoveBody { return; } - let ty::Coroutine(_, coroutine_args) = *coroutine_ty.kind() else { bug!("{body:#?}") }; - // We don't need to generate a by-move coroutine if the kind of the coroutine is - // already `FnOnce` -- that means that any upvars that the closure consumes have - // already been taken by-value. - let coroutine_kind = coroutine_args.as_coroutine().kind_ty().to_opt_closure_kind().unwrap(); - if coroutine_kind == ty::ClosureKind::FnOnce { + // We don't need to generate a by-move coroutine if the coroutine body was + // produced by the `CoroutineKindShim`, since it's already by-move. + if matches!(body.source.instance, ty::InstanceDef::CoroutineKindShim { .. }) { return; } + let ty::Coroutine(_, args) = *coroutine_ty.kind() else { bug!("{body:#?}") }; + let args = args.as_coroutine(); + + let coroutine_kind = args.kind_ty().to_opt_closure_kind().unwrap(); + let parent_def_id = tcx.local_parent(coroutine_def_id); let ty::CoroutineClosure(_, parent_args) = *tcx.type_of(parent_def_id).instantiate_identity().kind() @@ -128,6 +130,12 @@ impl<'tcx> MirPass<'tcx> for ByMoveBody { // the outer closure body -- we need to change the coroutine to take the // upvar by value. if coroutine_capture.is_by_ref() && !parent_capture.is_by_ref() { + assert_ne!( + coroutine_kind, + ty::ClosureKind::FnOnce, + "`FnOnce` coroutine-closures return coroutines that capture from \ + their body; it will always result in a borrowck error!" + ); by_ref_fields.insert(FieldIdx::from_usize(num_args + idx)); } diff --git a/src/tools/miri/tests/pass/async-closure-captures.rs b/src/tools/miri/tests/pass/async-closure-captures.rs index 3e33de32efb..cac26bfe146 100644 --- a/src/tools/miri/tests/pass/async-closure-captures.rs +++ b/src/tools/miri/tests/pass/async-closure-captures.rs @@ -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; + } } diff --git a/src/tools/miri/tests/pass/async-closure-captures.stdout b/src/tools/miri/tests/pass/async-closure-captures.stdout index a0db6d236fe..42a7999b2dc 100644 --- a/src/tools/miri/tests/pass/async-closure-captures.stdout +++ b/src/tools/miri/tests/pass/async-closure-captures.stdout @@ -8,3 +8,7 @@ Hello(3) Hello(4) Hello(4) Hello(5) +Hello(6) +Hello(7) +Hello(8) +Hello(9) diff --git a/tests/ui/async-await/async-closures/captures.rs b/tests/ui/async-await/async-closures/captures.rs index e3ab8713709..0a9d0529bf5 100644 --- a/tests/ui/async-await/async-closures/captures.rs +++ b/tests/ui/async-await/async-closures/captures.rs @@ -79,4 +79,38 @@ 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; + } } diff --git a/tests/ui/async-await/async-closures/captures.run.stdout b/tests/ui/async-await/async-closures/captures.run.stdout index a0db6d236fe..42a7999b2dc 100644 --- a/tests/ui/async-await/async-closures/captures.run.stdout +++ b/tests/ui/async-await/async-closures/captures.run.stdout @@ -8,3 +8,7 @@ Hello(3) Hello(4) Hello(4) Hello(5) +Hello(6) +Hello(7) +Hello(8) +Hello(9) diff --git a/tests/ui/async-await/async-closures/wrong-fn-kind.rs b/tests/ui/async-await/async-closures/wrong-fn-kind.rs index 8502bb6e2d4..3d6f856874f 100644 --- a/tests/ui/async-await/async-closures/wrong-fn-kind.rs +++ b/tests/ui/async-await/async-closures/wrong-fn-kind.rs @@ -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() {} diff --git a/tests/ui/async-await/async-closures/wrong-fn-kind.stderr b/tests/ui/async-await/async-closures/wrong-fn-kind.stderr index d0f1948e48f..e56389b3202 100644 --- a/tests/ui/async-await/async-closures/wrong-fn-kind.stderr +++ b/tests/ui/async-await/async-closures/wrong-fn-kind.stderr @@ -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` + +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()) {} - | ^^^^^^^^^^ required by this bound in `needs_async_fn` +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`. |