diff options
5 files changed, 101 insertions, 54 deletions
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs index d270b4cf96b..389e8e7994d 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs @@ -829,7 +829,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { && let ty::Closure(closure_def_id, _) | ty::CoroutineClosure(closure_def_id, _) = *typeck_results.node_type(arg_hir_id).kind() { - // Otherwise, extract the closure kind from the obligation. + // Otherwise, extract the closure kind from the obligation, + // but only if we actually have an argument to deduce the + // closure type from... let mut err = self.report_closure_error( &obligation, closure_def_id, @@ -844,63 +846,72 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { let self_ty = trait_pred.self_ty().skip_binder(); - if let Some(expected_kind) = self.tcx.fn_trait_kind_from_def_id(trait_pred.def_id()) { - let (closure_def_id, found_args, by_ref_captures) = match *self_ty.kind() { - ty::Closure(def_id, args) => { - (def_id, args.as_closure().sig().map_bound(|sig| sig.inputs()[0]), None) - } - ty::CoroutineClosure(def_id, args) => ( - def_id, - args.as_coroutine_closure() - .coroutine_closure_sig() - .map_bound(|sig| sig.tupled_inputs_ty), - Some(args.as_coroutine_closure().coroutine_captures_by_ref_ty()), - ), - _ => return None, + let (expected_kind, trait_prefix) = + if let Some(expected_kind) = self.tcx.fn_trait_kind_from_def_id(trait_pred.def_id()) { + (expected_kind, "") + } else if let Some(expected_kind) = + self.tcx.async_fn_trait_kind_from_def_id(trait_pred.def_id()) + { + (expected_kind, "Async") + } else { + return None; }; - let expected_args = - trait_pred.map_bound(|trait_pred| trait_pred.trait_ref.args.type_at(1)); - - // Verify that the arguments are compatible. If the signature is - // mismatched, then we have a totally different error to report. - if self.enter_forall(found_args, |found_args| { - self.enter_forall(expected_args, |expected_args| { - !self.can_eq(obligation.param_env, expected_args, found_args) - }) - }) { - return None; + let (closure_def_id, found_args, by_ref_captures) = match *self_ty.kind() { + ty::Closure(def_id, args) => { + (def_id, args.as_closure().sig().map_bound(|sig| sig.inputs()[0]), None) } + ty::CoroutineClosure(def_id, args) => ( + def_id, + args.as_coroutine_closure() + .coroutine_closure_sig() + .map_bound(|sig| sig.tupled_inputs_ty), + Some(args.as_coroutine_closure().coroutine_captures_by_ref_ty()), + ), + _ => return None, + }; - if let Some(found_kind) = self.closure_kind(self_ty) - && !found_kind.extends(expected_kind) - { - let mut err = self.report_closure_error( - &obligation, - closure_def_id, - found_kind, - expected_kind, - "", - ); - self.note_obligation_cause(&mut err, &obligation); - return Some(err.emit()); - } + let expected_args = trait_pred.map_bound(|trait_pred| trait_pred.trait_ref.args.type_at(1)); - // If the closure has captures, then perhaps the reason that the trait - // is unimplemented is because async closures don't implement `Fn`/`FnMut` - // if they have captures. - if let Some(by_ref_captures) = by_ref_captures - && let ty::FnPtr(sig_tys, _) = by_ref_captures.kind() - && !sig_tys.skip_binder().output().is_unit() - { - let mut err = self.dcx().create_err(AsyncClosureNotFn { - span: self.tcx.def_span(closure_def_id), - kind: expected_kind.as_str(), - }); - self.note_obligation_cause(&mut err, &obligation); - return Some(err.emit()); - } + // Verify that the arguments are compatible. If the signature is + // mismatched, then we have a totally different error to report. + if self.enter_forall(found_args, |found_args| { + self.enter_forall(expected_args, |expected_args| { + !self.can_eq(obligation.param_env, expected_args, found_args) + }) + }) { + return None; } + + if let Some(found_kind) = self.closure_kind(self_ty) + && !found_kind.extends(expected_kind) + { + let mut err = self.report_closure_error( + &obligation, + closure_def_id, + found_kind, + expected_kind, + trait_prefix, + ); + self.note_obligation_cause(&mut err, &obligation); + return Some(err.emit()); + } + + // If the closure has captures, then perhaps the reason that the trait + // is unimplemented is because async closures don't implement `Fn`/`FnMut` + // if they have captures. + if let Some(by_ref_captures) = by_ref_captures + && let ty::FnPtr(sig_tys, _) = by_ref_captures.kind() + && !sig_tys.skip_binder().output().is_unit() + { + let mut err = self.dcx().create_err(AsyncClosureNotFn { + span: self.tcx.def_span(closure_def_id), + kind: expected_kind.as_str(), + }); + self.note_obligation_cause(&mut err, &obligation); + return Some(err.emit()); + } + None } diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs index b85c18c5312..bbf46fff71b 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs @@ -3191,7 +3191,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { false }; - if !is_upvar_tys_infer_tuple { + let is_builtin_async_fn_trait = + tcx.async_fn_trait_kind_from_def_id(data.parent_trait_pred.def_id()).is_some(); + + if !is_upvar_tys_infer_tuple && !is_builtin_async_fn_trait { let ty_str = tcx.short_string(ty, err.long_ty_path()); let msg = format!("required because it appears within the type `{ty_str}`"); match ty.kind() { diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index a58317dd56d..4ed27e406d2 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -984,8 +984,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { return Err(SelectionError::Unimplemented); } } else { - nested.push(obligation.with( + nested.push(Obligation::new( self.tcx(), + obligation.derived_cause(ObligationCauseCode::BuiltinDerived), + obligation.param_env, ty::TraitRef::new( self.tcx(), self.tcx().require_lang_item( diff --git a/tests/ui/async-await/async-closures/kind-due-to-rpit.rs b/tests/ui/async-await/async-closures/kind-due-to-rpit.rs new file mode 100644 index 00000000000..ad19d93b93a --- /dev/null +++ b/tests/ui/async-await/async-closures/kind-due-to-rpit.rs @@ -0,0 +1,14 @@ +//@ edition: 2024 + +// Make sure the error message is understandable when an `AsyncFn` goal is not satisfied +// (due to closure kind), and that goal originates from an RPIT. + +fn repro(foo: impl Into<bool>) -> impl AsyncFn() { + let inner_fn = async move || { + //~^ ERROR expected a closure that implements the `AsyncFn` trait + let _ = foo.into(); + }; + inner_fn +} + +fn main() {} diff --git a/tests/ui/async-await/async-closures/kind-due-to-rpit.stderr b/tests/ui/async-await/async-closures/kind-due-to-rpit.stderr new file mode 100644 index 00000000000..982cc50e14f --- /dev/null +++ b/tests/ui/async-await/async-closures/kind-due-to-rpit.stderr @@ -0,0 +1,17 @@ +error[E0525]: expected a closure that implements the `AsyncFn` trait, but this closure only implements `AsyncFnOnce` + --> $DIR/kind-due-to-rpit.rs:7:20 + | +LL | fn repro(foo: impl Into<bool>) -> impl AsyncFn() { + | -------------- the requirement to implement `AsyncFn` derives from here +LL | let inner_fn = async move || { + | ^^^^^^^^^^^^^ this closure implements `AsyncFnOnce`, not `AsyncFn` +LL | +LL | let _ = foo.into(); + | --- closure is `AsyncFnOnce` because it moves the variable `foo` out of its environment +LL | }; +LL | inner_fn + | -------- return type was inferred to be `{async closure@$DIR/kind-due-to-rpit.rs:7:20: 7:33}` here + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0525`. |