diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs index 69d826bbe7a..c7d2e4c22d2 100644 --- a/compiler/rustc_middle/src/traits/mod.rs +++ b/compiler/rustc_middle/src/traits/mod.rs @@ -588,6 +588,10 @@ pub enum SelectionError<'tcx> { /// Signaling that an error has already been emitted, to avoid /// multiple errors being shown. ErrorReporting, + /// Computing an opaque type's hidden type caused an error (e.g. a cycle error). + /// We can thus not know whether the hidden type implements an auto trait, so + /// we should not presume anything about it. + OpaqueTypeAutoTraitLeakageUnknown(DefId), } #[derive(Clone, Debug, TypeVisitable, Lift)] diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs index e9d3ead5553..ec5782cc916 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -30,7 +30,7 @@ use rustc_infer::infer::{InferOk, TypeTrace}; use rustc_middle::traits::select::OverflowError; use rustc_middle::traits::solve::Goal; -use rustc_middle::traits::SelectionOutputTypeParameterMismatch; +use rustc_middle::traits::{DefiningAnchor, SelectionOutputTypeParameterMismatch}; use rustc_middle::ty::abstract_const::NotConstEvaluatable; use rustc_middle::ty::error::{ExpectedFound, TypeError}; use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable}; @@ -1152,6 +1152,11 @@ fn report_selection_error( } } + SelectionError::OpaqueTypeAutoTraitLeakageUnknown(def_id) => self.report_opaque_type_auto_trait_leakage( + &obligation, + def_id, + ), + TraitNotObjectSafe(did) => { let violations = self.tcx.object_safety_violations(did); report_object_safety_error(self.tcx, span, did, violations) @@ -1465,6 +1470,12 @@ fn report_type_parameter_mismatch_cyclic_type_error( terr: TypeError<'tcx>, ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>; + fn report_opaque_type_auto_trait_leakage( + &self, + obligation: &PredicateObligation<'tcx>, + def_id: DefId, + ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>; + fn report_type_parameter_mismatch_error( &self, obligation: &PredicateObligation<'tcx>, @@ -3186,6 +3197,39 @@ fn report_type_parameter_mismatch_cyclic_type_error( ) } + fn report_opaque_type_auto_trait_leakage( + &self, + obligation: &PredicateObligation<'tcx>, + def_id: DefId, + ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { + let name = match self.tcx.opaque_type_origin(def_id.expect_local()) { + hir::OpaqueTyOrigin::FnReturn(_) | hir::OpaqueTyOrigin::AsyncFn(_) => { + format!("opaque type") + } + hir::OpaqueTyOrigin::TyAlias { .. } => { + format!("`{}`", self.tcx.def_path_debug_str(def_id)) + } + }; + let mut err = self.tcx.sess.struct_span_err( + obligation.cause.span, + format!("cannot check whether the hidden type of {name} satisfies auto traits"), + ); + err.span_note(self.tcx.def_span(def_id), "opaque type is declared here"); + match self.defining_use_anchor { + DefiningAnchor::Bubble | DefiningAnchor::Error => {} + DefiningAnchor::Bind(bind) => { + err.span_note( + self.tcx.def_ident_span(bind).unwrap_or_else(|| self.tcx.def_span(bind)), + "this item depends on auto traits of the hidden type, \ + but may also be registering the hidden type. \ + This is not supported right now. \ + You can try moving the opaque type and the item that actually registers a hidden type into a new submodule".to_string(), + ); + } + }; + err + } + fn report_type_parameter_mismatch_error( &self, obligation: &PredicateObligation<'tcx>, diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index 24e895bc184..744c85ed51f 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -67,7 +67,7 @@ pub(super) fn confirm_candidate( } AutoImplCandidate => { - let data = self.confirm_auto_impl_candidate(obligation); + let data = self.confirm_auto_impl_candidate(obligation)?; ImplSource::Builtin(data) } @@ -376,12 +376,12 @@ fn flatten_answer_tree<'tcx>( fn confirm_auto_impl_candidate( &mut self, obligation: &TraitObligation<'tcx>, - ) -> Vec> { + ) -> Result>, SelectionError<'tcx>> { debug!(?obligation, "confirm_auto_impl_candidate"); let self_ty = self.infcx.shallow_resolve(obligation.predicate.self_ty()); - let types = self.constituent_types_for_ty(self_ty); - self.vtable_auto_impl(obligation, obligation.predicate.def_id(), types) + let types = self.constituent_types_for_ty(self_ty)?; + Ok(self.vtable_auto_impl(obligation, obligation.predicate.def_id(), types)) } /// See `confirm_auto_impl_candidate`. diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index eb11163de42..fece05cbb7d 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -2294,8 +2294,8 @@ fn copy_clone_conditions( fn constituent_types_for_ty( &self, t: ty::Binder<'tcx, Ty<'tcx>>, - ) -> ty::Binder<'tcx, Vec>> { - match *t.skip_binder().kind() { + ) -> Result>>, SelectionError<'tcx>> { + Ok(match *t.skip_binder().kind() { ty::Uint(_) | ty::Int(_) | ty::Bool @@ -2359,12 +2359,16 @@ fn constituent_types_for_ty( } ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => { + let ty = self.tcx().type_of(def_id); + if ty.skip_binder().references_error() { + return Err(SelectionError::OpaqueTypeAutoTraitLeakageUnknown(def_id)); + } // We can resolve the `impl Trait` to its concrete type, // which enforces a DAG between the functions requiring // the auto trait bounds in question. - t.rebind(vec![self.tcx().type_of(def_id).subst(self.tcx(), substs)]) + t.rebind(vec![ty.subst(self.tcx(), substs)]) } - } + }) } fn collect_predicates_for_types( diff --git a/tests/ui/generator/layout-error.rs b/tests/ui/generator/layout-error.rs index 7c3d187409a..44cfc1d70dd 100644 --- a/tests/ui/generator/layout-error.rs +++ b/tests/ui/generator/layout-error.rs @@ -24,5 +24,6 @@ async fn cb() { type F = impl Future; // Check that statics are inhabited computes they layout. static POOL: Task = Task::new(); + //~^ ERROR: cannot check whether the hidden type of `layout_error[b009]::main::F::{opaque#0}` satisfies auto traits Task::spawn(&POOL, || cb()); } diff --git a/tests/ui/generator/layout-error.stderr b/tests/ui/generator/layout-error.stderr index b1a258f4f2c..ea3b25551c4 100644 --- a/tests/ui/generator/layout-error.stderr +++ b/tests/ui/generator/layout-error.stderr @@ -4,6 +4,24 @@ error[E0425]: cannot find value `Foo` in this scope LL | let a = Foo; | ^^^ not found in this scope -error: aborting due to previous error +error: cannot check whether the hidden type of `layout_error[b009]::main::F::{opaque#0}` satisfies auto traits + --> $DIR/layout-error.rs:26:18 + | +LL | static POOL: Task = Task::new(); + | ^^^^^^^ + | +note: opaque type is declared here + --> $DIR/layout-error.rs:24:14 + | +LL | type F = impl Future; + | ^^^^^^^^^^^ +note: required because it appears within the type `Task` + --> $DIR/layout-error.rs:9:12 + | +LL | pub struct Task(F); + | ^^^^ + = note: shared static variables must have a type that implements `Sync` + +error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0425`. diff --git a/tests/ui/impl-trait/auto-trait-leak.rs b/tests/ui/impl-trait/auto-trait-leak.rs index c2fbbf94fd6..d71c0987935 100644 --- a/tests/ui/impl-trait/auto-trait-leak.rs +++ b/tests/ui/impl-trait/auto-trait-leak.rs @@ -3,21 +3,23 @@ fn send(_: T) {} -fn main() { -} +fn main() {} // Cycles should work as the deferred obligations are // independently resolved and only require the concrete // return type, which can't depend on the obligation. fn cycle1() -> impl Clone { //~^ ERROR cycle detected + //~| ERROR cycle detected send(cycle2().clone()); + //~^ ERROR: cannot check whether the hidden type of opaque type satisfies auto traits Rc::new(Cell::new(5)) } fn cycle2() -> impl Clone { send(cycle1().clone()); + //~^ ERROR: cannot check whether the hidden type of opaque type satisfies auto traits Rc::new(String::from("foo")) } diff --git a/tests/ui/impl-trait/auto-trait-leak.stderr b/tests/ui/impl-trait/auto-trait-leak.stderr index c0c4cd5013e..92a9763bc9b 100644 --- a/tests/ui/impl-trait/auto-trait-leak.stderr +++ b/tests/ui/impl-trait/auto-trait-leak.stderr @@ -1,5 +1,5 @@ error[E0391]: cycle detected when computing type of `cycle1::{opaque#0}` - --> $DIR/auto-trait-leak.rs:12:16 + --> $DIR/auto-trait-leak.rs:11:16 | LL | fn cycle1() -> impl Clone { | ^^^^^^^^^^ @@ -11,12 +11,12 @@ LL | send(cycle2().clone()); | ^^^^ = note: ...which requires evaluating trait selection obligation `cycle2::{opaque#0}: core::marker::Send`... note: ...which requires computing type of `cycle2::{opaque#0}`... - --> $DIR/auto-trait-leak.rs:19:16 + --> $DIR/auto-trait-leak.rs:20:16 | LL | fn cycle2() -> impl Clone { | ^^^^^^^^^^ note: ...which requires type-checking `cycle2`... - --> $DIR/auto-trait-leak.rs:20:5 + --> $DIR/auto-trait-leak.rs:21:5 | LL | send(cycle1().clone()); | ^^^^ @@ -34,6 +34,89 @@ LL | | Rc::new(String::from("foo")) LL | | } | |_^ -error: aborting due to previous error +error[E0391]: cycle detected when computing type of `cycle1::{opaque#0}` + --> $DIR/auto-trait-leak.rs:11:16 + | +LL | fn cycle1() -> impl Clone { + | ^^^^^^^^^^ + | +note: ...which requires type-checking `cycle1`... + --> $DIR/auto-trait-leak.rs:14:5 + | +LL | send(cycle2().clone()); + | ^^^^ + = note: ...which requires evaluating trait selection obligation `cycle2::{opaque#0}: core::marker::Send`... +note: ...which requires computing type of `cycle2::{opaque#0}`... + --> $DIR/auto-trait-leak.rs:20:16 + | +LL | fn cycle2() -> impl Clone { + | ^^^^^^^^^^ +note: ...which requires type-checking `cycle2`... + --> $DIR/auto-trait-leak.rs:20:1 + | +LL | fn cycle2() -> impl Clone { + | ^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: ...which again requires computing type of `cycle1::{opaque#0}`, completing the cycle +note: cycle used when checking item types in top-level module + --> $DIR/auto-trait-leak.rs:1:1 + | +LL | / use std::cell::Cell; +LL | | use std::rc::Rc; +LL | | +LL | | fn send(_: T) {} +... | +LL | | Rc::new(String::from("foo")) +LL | | } + | |_^ + +error: cannot check whether the hidden type of opaque type satisfies auto traits + --> $DIR/auto-trait-leak.rs:21:10 + | +LL | send(cycle1().clone()); + | ---- ^^^^^^^^^^^^^^^^ + | | + | required by a bound introduced by this call + | +note: opaque type is declared here + --> $DIR/auto-trait-leak.rs:11:16 + | +LL | fn cycle1() -> impl Clone { + | ^^^^^^^^^^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/auto-trait-leak.rs:20:4 + | +LL | fn cycle2() -> impl Clone { + | ^^^^^^ +note: required by a bound in `send` + --> $DIR/auto-trait-leak.rs:4:12 + | +LL | fn send(_: T) {} + | ^^^^ required by this bound in `send` + +error: cannot check whether the hidden type of opaque type satisfies auto traits + --> $DIR/auto-trait-leak.rs:14:10 + | +LL | send(cycle2().clone()); + | ---- ^^^^^^^^^^^^^^^^ + | | + | required by a bound introduced by this call + | +note: opaque type is declared here + --> $DIR/auto-trait-leak.rs:20:16 + | +LL | fn cycle2() -> impl Clone { + | ^^^^^^^^^^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/auto-trait-leak.rs:11:4 + | +LL | fn cycle1() -> impl Clone { + | ^^^^^^ +note: required by a bound in `send` + --> $DIR/auto-trait-leak.rs:4:12 + | +LL | fn send(_: T) {} + | ^^^^ required by this bound in `send` + +error: aborting due to 4 previous errors For more information about this error, try `rustc --explain E0391`. diff --git a/tests/ui/impl-trait/issue-103181-2.rs b/tests/ui/impl-trait/issue-103181-2.rs index b43ac45075e..34deb98beef 100644 --- a/tests/ui/impl-trait/issue-103181-2.rs +++ b/tests/ui/impl-trait/issue-103181-2.rs @@ -24,6 +24,8 @@ async fn iceice() B: Send, // <- a second bound { normalize(broken_fut(), ()); + //~^ ERROR: cannot check whether the hidden type of opaque type satisfies auto traits + //~| ERROR: cannot check whether the hidden type of opaque type satisfies auto traits } fn main() {} diff --git a/tests/ui/impl-trait/issue-103181-2.stderr b/tests/ui/impl-trait/issue-103181-2.stderr index 5eb2dd9184b..cb5253ea6cd 100644 --- a/tests/ui/impl-trait/issue-103181-2.stderr +++ b/tests/ui/impl-trait/issue-103181-2.stderr @@ -4,6 +4,61 @@ error[E0425]: cannot find value `ident_error` in this scope LL | ident_error; | ^^^^^^^^^^^ not found in this scope -error: aborting due to previous error +error: cannot check whether the hidden type of opaque type satisfies auto traits + --> $DIR/issue-103181-2.rs:26:15 + | +LL | normalize(broken_fut(), ()); + | --------- ^^^^^^^^^^^^ + | | + | required by a bound introduced by this call + | +note: opaque type is declared here + --> $DIR/issue-103181-2.rs:11:23 + | +LL | async fn broken_fut() { + | ^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/issue-103181-2.rs:20:10 + | +LL | async fn iceice() + | ^^^^^^ +note: required for `impl Future` to implement `SendFuture` + --> $DIR/issue-103181-2.rs:7:17 + | +LL | impl SendFuture for Fut { + | ---- ^^^^^^^^^^ ^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `normalize` + --> $DIR/issue-103181-2.rs:18:19 + | +LL | fn normalize(_: Fut, _: Fut::Output) {} + | ^^^^^^^^^^ required by this bound in `normalize` + +error: cannot check whether the hidden type of opaque type satisfies auto traits + --> $DIR/issue-103181-2.rs:26:5 + | +LL | normalize(broken_fut(), ()); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: opaque type is declared here + --> $DIR/issue-103181-2.rs:11:23 + | +LL | async fn broken_fut() { + | ^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/issue-103181-2.rs:20:10 + | +LL | async fn iceice() + | ^^^^^^ +note: required for `impl Future` to implement `SendFuture` + --> $DIR/issue-103181-2.rs:7:17 + | +LL | impl SendFuture for Fut { + | ---- ^^^^^^^^^^ ^^^ + | | + | unsatisfied trait bound introduced here + +error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0425`. diff --git a/tests/ui/type-alias-impl-trait/auto-trait-leakage3.rs b/tests/ui/type-alias-impl-trait/auto-trait-leakage3.rs index 43cd49d6ed7..fd3f9c61420 100644 --- a/tests/ui/type-alias-impl-trait/auto-trait-leakage3.rs +++ b/tests/ui/type-alias-impl-trait/auto-trait-leakage3.rs @@ -6,6 +6,7 @@ mod m { pub type Foo = impl std::fmt::Debug; //~^ ERROR: cycle detected when computing type of `m::Foo::{opaque#0}` [E0391] + //~| ERROR: cycle detected when computing type of `m::Foo::{opaque#0}` [E0391] pub fn foo() -> Foo { 22_u32 @@ -13,6 +14,7 @@ pub fn foo() -> Foo { pub fn bar() { is_send(foo()); + //~^ ERROR: cannot check whether the hidden type of `auto_trait_leakage3[211d]::m::Foo::{opaque#0} } fn is_send(_: T) {} diff --git a/tests/ui/type-alias-impl-trait/auto-trait-leakage3.stderr b/tests/ui/type-alias-impl-trait/auto-trait-leakage3.stderr index 6df59d98150..dd56c59bf5f 100644 --- a/tests/ui/type-alias-impl-trait/auto-trait-leakage3.stderr +++ b/tests/ui/type-alias-impl-trait/auto-trait-leakage3.stderr @@ -5,7 +5,7 @@ LL | pub type Foo = impl std::fmt::Debug; | ^^^^^^^^^^^^^^^^^^^^ | note: ...which requires type-checking `m::bar`... - --> $DIR/auto-trait-leakage3.rs:15:9 + --> $DIR/auto-trait-leakage3.rs:16:9 | LL | is_send(foo()); | ^^^^^^^ @@ -17,6 +17,48 @@ note: cycle used when checking item types in module `m` LL | mod m { | ^^^^^ -error: aborting due to previous error +error[E0391]: cycle detected when computing type of `m::Foo::{opaque#0}` + --> $DIR/auto-trait-leakage3.rs:7:20 + | +LL | pub type Foo = impl std::fmt::Debug; + | ^^^^^^^^^^^^^^^^^^^^ + | +note: ...which requires type-checking `m::bar`... + --> $DIR/auto-trait-leakage3.rs:15:5 + | +LL | pub fn bar() { + | ^^^^^^^^^^^^ + = note: ...which again requires computing type of `m::Foo::{opaque#0}`, completing the cycle +note: cycle used when checking item types in module `m` + --> $DIR/auto-trait-leakage3.rs:6:1 + | +LL | mod m { + | ^^^^^ + +error: cannot check whether the hidden type of `auto_trait_leakage3[211d]::m::Foo::{opaque#0}` satisfies auto traits + --> $DIR/auto-trait-leakage3.rs:16:17 + | +LL | is_send(foo()); + | ------- ^^^^^ + | | + | required by a bound introduced by this call + | +note: opaque type is declared here + --> $DIR/auto-trait-leakage3.rs:7:20 + | +LL | pub type Foo = impl std::fmt::Debug; + | ^^^^^^^^^^^^^^^^^^^^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/auto-trait-leakage3.rs:15:12 + | +LL | pub fn bar() { + | ^^^ +note: required by a bound in `is_send` + --> $DIR/auto-trait-leakage3.rs:20:19 + | +LL | fn is_send(_: T) {} + | ^^^^ required by this bound in `is_send` + +error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0391`. diff --git a/tests/ui/type-alias-impl-trait/inference-cycle.rs b/tests/ui/type-alias-impl-trait/inference-cycle.rs index 01a4b9c0bb8..093afc25249 100644 --- a/tests/ui/type-alias-impl-trait/inference-cycle.rs +++ b/tests/ui/type-alias-impl-trait/inference-cycle.rs @@ -4,6 +4,7 @@ mod m { pub type Foo = impl std::fmt::Debug; //~^ ERROR cycle detected + //~| ERROR cycle detected // Cycle: error today, but it'd be nice if it eventually worked @@ -13,6 +14,7 @@ pub fn foo() -> Foo { pub fn bar() { is_send(foo()); // Today: error + //~^ ERROR: cannot check whether the hidden type of `inference_cycle[4ecc]::m::Foo::{opaque#0}` satisfies auto traits } fn baz() { diff --git a/tests/ui/type-alias-impl-trait/inference-cycle.stderr b/tests/ui/type-alias-impl-trait/inference-cycle.stderr index 03ffe38ba2e..4d5f367476b 100644 --- a/tests/ui/type-alias-impl-trait/inference-cycle.stderr +++ b/tests/ui/type-alias-impl-trait/inference-cycle.stderr @@ -5,7 +5,7 @@ LL | pub type Foo = impl std::fmt::Debug; | ^^^^^^^^^^^^^^^^^^^^ | note: ...which requires type-checking `m::bar`... - --> $DIR/inference-cycle.rs:15:9 + --> $DIR/inference-cycle.rs:16:9 | LL | is_send(foo()); // Today: error | ^^^^^^^ @@ -17,6 +17,48 @@ note: cycle used when checking item types in module `m` LL | mod m { | ^^^^^ -error: aborting due to previous error +error[E0391]: cycle detected when computing type of `m::Foo::{opaque#0}` + --> $DIR/inference-cycle.rs:5:20 + | +LL | pub type Foo = impl std::fmt::Debug; + | ^^^^^^^^^^^^^^^^^^^^ + | +note: ...which requires type-checking `m::bar`... + --> $DIR/inference-cycle.rs:15:5 + | +LL | pub fn bar() { + | ^^^^^^^^^^^^ + = note: ...which again requires computing type of `m::Foo::{opaque#0}`, completing the cycle +note: cycle used when checking item types in module `m` + --> $DIR/inference-cycle.rs:4:1 + | +LL | mod m { + | ^^^^^ + +error: cannot check whether the hidden type of `inference_cycle[4ecc]::m::Foo::{opaque#0}` satisfies auto traits + --> $DIR/inference-cycle.rs:16:17 + | +LL | is_send(foo()); // Today: error + | ------- ^^^^^ + | | + | required by a bound introduced by this call + | +note: opaque type is declared here + --> $DIR/inference-cycle.rs:5:20 + | +LL | pub type Foo = impl std::fmt::Debug; + | ^^^^^^^^^^^^^^^^^^^^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/inference-cycle.rs:15:12 + | +LL | pub fn bar() { + | ^^^ +note: required by a bound in `is_send` + --> $DIR/inference-cycle.rs:24:19 + | +LL | fn is_send(_: T) {} + | ^^^^ required by this bound in `is_send` + +error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0391`. diff --git a/tests/ui/type-alias-impl-trait/reveal_local.rs b/tests/ui/type-alias-impl-trait/reveal_local.rs index 7ecb5535301..75015e41c3d 100644 --- a/tests/ui/type-alias-impl-trait/reveal_local.rs +++ b/tests/ui/type-alias-impl-trait/reveal_local.rs @@ -4,13 +4,16 @@ type Foo = impl Debug; //~^ ERROR cycle detected +//~| ERROR cycle detected +//~| ERROR cycle detected -fn is_send() { } +fn is_send() {} fn not_good() { // Error: this function does not constrain `Foo` to any particular // hidden type, so it cannot rely on `Send` being true. is_send::(); + //~^ ERROR: cannot check whether the hidden type of `reveal_local[9507]::Foo::{opaque#0}` satisfies auto traits } fn not_gooder() { @@ -20,6 +23,7 @@ fn not_gooder() { // while we could know this from the hidden type, it would // need extra roundabout logic to support it. is_send::(); + //~^ ERROR: cannot check whether the hidden type of `reveal_local[9507]::Foo::{opaque#0}` satisfies auto traits } fn main() {} diff --git a/tests/ui/type-alias-impl-trait/reveal_local.stderr b/tests/ui/type-alias-impl-trait/reveal_local.stderr index 27fded33329..202a87ecbb7 100644 --- a/tests/ui/type-alias-impl-trait/reveal_local.stderr +++ b/tests/ui/type-alias-impl-trait/reveal_local.stderr @@ -5,7 +5,7 @@ LL | type Foo = impl Debug; | ^^^^^^^^^^ | note: ...which requires type-checking `not_good`... - --> $DIR/reveal_local.rs:13:5 + --> $DIR/reveal_local.rs:15:5 | LL | is_send::(); | ^^^^^^^^^^^^^^ @@ -23,6 +23,98 @@ LL | | LL | | fn main() {} | |____________^ -error: aborting due to previous error +error[E0391]: cycle detected when computing type of `Foo::{opaque#0}` + --> $DIR/reveal_local.rs:5:12 + | +LL | type Foo = impl Debug; + | ^^^^^^^^^^ + | +note: ...which requires type-checking `not_good`... + --> $DIR/reveal_local.rs:12:1 + | +LL | fn not_good() { + | ^^^^^^^^^^^^^ + = note: ...which again requires computing type of `Foo::{opaque#0}`, completing the cycle +note: cycle used when checking item types in top-level module + --> $DIR/reveal_local.rs:1:1 + | +LL | / #![feature(type_alias_impl_trait)] +LL | | +LL | | use std::fmt::Debug; +LL | | +... | +LL | | +LL | | fn main() {} + | |____________^ + +error: cannot check whether the hidden type of `reveal_local[9507]::Foo::{opaque#0}` satisfies auto traits + --> $DIR/reveal_local.rs:15:15 + | +LL | is_send::(); + | ^^^ + | +note: opaque type is declared here + --> $DIR/reveal_local.rs:5:12 + | +LL | type Foo = impl Debug; + | ^^^^^^^^^^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/reveal_local.rs:12:4 + | +LL | fn not_good() { + | ^^^^^^^^ +note: required by a bound in `is_send` + --> $DIR/reveal_local.rs:10:15 + | +LL | fn is_send() {} + | ^^^^ required by this bound in `is_send` + +error[E0391]: cycle detected when computing type of `Foo::{opaque#0}` + --> $DIR/reveal_local.rs:5:12 + | +LL | type Foo = impl Debug; + | ^^^^^^^^^^ + | +note: ...which requires type-checking `not_gooder`... + --> $DIR/reveal_local.rs:19:1 + | +LL | fn not_gooder() { + | ^^^^^^^^^^^^^^^ + = note: ...which again requires computing type of `Foo::{opaque#0}`, completing the cycle +note: cycle used when checking item types in top-level module + --> $DIR/reveal_local.rs:1:1 + | +LL | / #![feature(type_alias_impl_trait)] +LL | | +LL | | use std::fmt::Debug; +LL | | +... | +LL | | +LL | | fn main() {} + | |____________^ + +error: cannot check whether the hidden type of `reveal_local[9507]::Foo::{opaque#0}` satisfies auto traits + --> $DIR/reveal_local.rs:25:15 + | +LL | is_send::(); + | ^^^ + | +note: opaque type is declared here + --> $DIR/reveal_local.rs:5:12 + | +LL | type Foo = impl Debug; + | ^^^^^^^^^^ +note: this item depends on auto traits of the hidden type, but may also be registering the hidden type. This is not supported right now. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule + --> $DIR/reveal_local.rs:19:4 + | +LL | fn not_gooder() { + | ^^^^^^^^^^ +note: required by a bound in `is_send` + --> $DIR/reveal_local.rs:10:15 + | +LL | fn is_send() {} + | ^^^^ required by this bound in `is_send` + +error: aborting due to 5 previous errors For more information about this error, try `rustc --explain E0391`.