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| author | Esteban Küber <esteban@kuber.com.ar> | 2020-10-15 17:23:45 -0700 |
|---|---|---|
| committer | Esteban Küber <esteban@kuber.com.ar> | 2020-10-20 09:26:14 -0700 |
| commit | ae0e3d051178193aec39cb7ea8110301339b3e44 (patch) | |
| tree | 0fe1ab087d84a3baaef9565cb6c836e4191ef2f2 | |
| parent | 9832374f6e378971e1a933362cf9781b121bb845 (diff) | |
| download | rust-ae0e3d051178193aec39cb7ea8110301339b3e44.tar.gz rust-ae0e3d051178193aec39cb7ea8110301339b3e44.zip | |
Tweak "object unsafe" errors
Fix #77598.
57 files changed, 699 insertions, 421 deletions
diff --git a/compiler/rustc_infer/src/traits/error_reporting/mod.rs b/compiler/rustc_infer/src/traits/error_reporting/mod.rs index f873358ff9f..63cfdbd170a 100644 --- a/compiler/rustc_infer/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_infer/src/traits/error_reporting/mod.rs @@ -2,12 +2,12 @@ use super::ObjectSafetyViolation; use crate::infer::InferCtxt; use rustc_data_structures::fx::FxHashSet; -use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder}; +use rustc_errors::{struct_span_err, DiagnosticBuilder}; use rustc_hir as hir; use rustc_hir::def_id::DefId; use rustc_middle::ty::TyCtxt; use rustc_span::symbol::Symbol; -use rustc_span::Span; +use rustc_span::{MultiSpan, Span}; use std::fmt; impl<'a, 'tcx> InferCtxt<'a, 'tcx> { @@ -57,7 +57,8 @@ pub fn report_object_safety_error( err.span_label(span, format!("the trait `{}` cannot be made into an object", trait_str)); let mut reported_violations = FxHashSet::default(); - let mut had_span_label = false; + let mut multi_span = vec![]; + let mut messages = vec![]; for violation in violations { if let ObjectSafetyViolation::SizedSelf(sp) = &violation { if !sp.is_empty() { @@ -71,31 +72,37 @@ pub fn report_object_safety_error( let msg = if trait_span.is_none() || spans.is_empty() { format!("the trait cannot be made into an object because {}", violation.error_msg()) } else { - had_span_label = true; format!("...because {}", violation.error_msg()) }; if spans.is_empty() { err.note(&msg); } else { for span in spans { - err.span_label(span, &msg); + multi_span.push(span); + messages.push(msg.clone()); } } - match (trait_span, violation.solution()) { - (Some(_), Some((note, None))) => { - err.help(¬e); - } - (Some(_), Some((note, Some((sugg, span))))) => { - err.span_suggestion(span, ¬e, sugg, Applicability::MachineApplicable); - } + if trait_span.is_some() { // Only provide the help if its a local trait, otherwise it's not actionable. - _ => {} + violation.solution(&mut err); } } } - if let (Some(trait_span), true) = (trait_span, had_span_label) { - err.span_label(trait_span, "this trait cannot be made into an object..."); + let has_multi_span = !multi_span.is_empty(); + let mut note_span = MultiSpan::from_spans(multi_span.clone()); + if let (Some(trait_span), true) = (trait_span, has_multi_span) { + note_span + .push_span_label(trait_span, "this trait cannot be made into an object...".to_string()); } + for (span, msg) in multi_span.into_iter().zip(messages.into_iter()) { + note_span.push_span_label(span, msg); + } + err.span_note( + note_span, + "for a trait to be \"object safe\" it needs to allow building a vtable to allow the call \ + to be resolvable dynamically; for more information visit \ + <https://doc.rust-lang.org/reference/items/traits.html#object-safety>", + ); if tcx.sess.trait_methods_not_found.borrow().contains(&span) { // Avoid emitting error caused by non-existing method (#58734) diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs index 1dd6d590d90..f21dc71d224 100644 --- a/compiler/rustc_middle/src/traits/mod.rs +++ b/compiler/rustc_middle/src/traits/mod.rs @@ -13,6 +13,7 @@ use crate::mir::interpret::ErrorHandled; use crate::ty::subst::SubstsRef; use crate::ty::{self, AdtKind, Ty, TyCtxt}; +use rustc_errors::{Applicability, DiagnosticBuilder}; use rustc_hir as hir; use rustc_hir::def_id::DefId; use rustc_span::symbol::Symbol; @@ -652,7 +653,7 @@ impl ObjectSafetyViolation { .into() } } - ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(_), _) => { + ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(_, _, _), _) => { format!("associated function `{}` has no `self` parameter", name).into() } ObjectSafetyViolation::Method( @@ -686,32 +687,65 @@ impl ObjectSafetyViolation { } } - pub fn solution(&self) -> Option<(String, Option<(String, Span)>)> { - Some(match *self { - ObjectSafetyViolation::SizedSelf(_) | ObjectSafetyViolation::SupertraitSelf(_) => { - return None; + pub fn solution(&self, err: &mut DiagnosticBuilder<'_>) { + match *self { + ObjectSafetyViolation::SizedSelf(_) | ObjectSafetyViolation::SupertraitSelf(_) => {} + ObjectSafetyViolation::Method( + name, + MethodViolationCode::StaticMethod(sugg, self_span, has_args), + _, + ) => { + err.span_suggestion( + self_span, + &format!( + "consider turning `{}` into a method by giving it a `&self` argument", + name + ), + format!("&self{}", if has_args { ", " } else { "" }), + Applicability::MaybeIncorrect, + ); + match sugg { + Some((sugg, span)) => { + err.span_suggestion( + span, + &format!( + "alternatively, consider constraining `{}` so it does not apply to \ + trait objects", + name + ), + sugg.to_string(), + Applicability::MaybeIncorrect, + ); + } + None => { + err.help(&format!( + "consider turning `{}` into a method by giving it a `&self` \ + argument or constraining it so it does not apply to trait objects", + name + )); + } + } } - ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(sugg), _) => ( - format!( - "consider turning `{}` into a method by giving it a `&self` argument or \ - constraining it so it does not apply to trait objects", - name - ), - sugg.map(|(sugg, sp)| (sugg.to_string(), sp)), - ), ObjectSafetyViolation::Method( name, MethodViolationCode::UndispatchableReceiver, span, - ) => ( - format!("consider changing method `{}`'s `self` parameter to be `&self`", name), - Some(("&Self".to_string(), span)), - ), + ) => { + err.span_suggestion( + span, + &format!( + "consider changing method `{}`'s `self` parameter to be `&self`", + name + ), + "&Self".to_string(), + Applicability::MachineApplicable, + ); + } ObjectSafetyViolation::AssocConst(name, _) | ObjectSafetyViolation::Method(name, ..) => { - (format!("consider moving `{}` to another trait", name), None) + err.help(&format!("consider moving `{}` to another trait", name)); } - }) + } } pub fn spans(&self) -> SmallVec<[Span; 1]> { @@ -735,7 +769,7 @@ impl ObjectSafetyViolation { #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)] pub enum MethodViolationCode { /// e.g., `fn foo()` - StaticMethod(Option<(&'static str, Span)>), + StaticMethod(Option<(&'static str, Span)>, Span, bool /* has args */), /// e.g., `fn foo(&self, x: Self)` ReferencesSelfInput(usize), diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs index 0e43f1655dd..a170d963c5c 100644 --- a/compiler/rustc_trait_selection/src/traits/object_safety.rs +++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs @@ -13,7 +13,7 @@ use super::elaborate_predicates; use crate::infer::TyCtxtInferExt; use crate::traits::query::evaluate_obligation::InferCtxtExt; use crate::traits::{self, Obligation, ObligationCause}; -use rustc_errors::{Applicability, FatalError}; +use rustc_errors::FatalError; use rustc_hir as hir; use rustc_hir::def_id::DefId; use rustc_middle::ty::subst::{GenericArg, InternalSubsts, Subst}; @@ -21,7 +21,7 @@ use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeVisitor, WithConstnes use rustc_middle::ty::{Predicate, ToPredicate}; use rustc_session::lint::builtin::WHERE_CLAUSES_OBJECT_SAFETY; use rustc_span::symbol::Symbol; -use rustc_span::Span; +use rustc_span::{MultiSpan, Span}; use smallvec::SmallVec; use std::array; @@ -112,33 +112,35 @@ fn object_safety_violations_for_trait( tcx.def_path_str(trait_def_id) )); let node = tcx.hir().get_if_local(trait_def_id); - let msg = if let Some(hir::Node::Item(item)) = node { - err.span_label( + let mut spans = MultiSpan::from_span(*span); + if let Some(hir::Node::Item(item)) = node { + spans.push_span_label( item.ident.span, - "this trait cannot be made into an object...", + "this trait cannot be made into an object...".into(), + ); + spans.push_span_label( + *span, + format!("...because {}", violation.error_msg()), ); - format!("...because {}", violation.error_msg()) } else { - format!( - "the trait cannot be made into an object because {}", - violation.error_msg() - ) + spans.push_span_label( + *span, + format!( + "the trait cannot be made into an object because {}", + violation.error_msg() + ), + ); }; - err.span_label(*span, &msg); - match (node, violation.solution()) { - (Some(_), Some((note, None))) => { - err.help(¬e); - } - (Some(_), Some((note, Some((sugg, span))))) => { - err.span_suggestion( - span, - ¬e, - sugg, - Applicability::MachineApplicable, - ); - } - // Only provide the help if its a local trait, otherwise it's not actionable. - _ => {} + err.span_note( + spans, + "for a trait to be \"object safe\" it needs to allow building a vtable \ + to allow the call to be resolvable dynamically; for more information \ + visit <https://doc.rust-lang.org/reference/items/traits.html\ + #object-safety>", + ); + if node.is_some() { + // Only provide the help if its a local trait, otherwise it's not + violation.solution(&mut err); } err.emit(); }, @@ -385,6 +387,8 @@ fn virtual_call_violation_for_method<'tcx>( trait_def_id: DefId, method: &ty::AssocItem, ) -> Option<MethodViolationCode> { + let sig = tcx.fn_sig(method.def_id); + // The method's first parameter must be named `self` if !method.fn_has_self_parameter { // We'll attempt to provide a structured suggestion for `Self: Sized`. @@ -395,11 +399,21 @@ fn virtual_call_violation_for_method<'tcx>( [.., pred] => (", Self: Sized", pred.span().shrink_to_hi()), }, ); - return Some(MethodViolationCode::StaticMethod(sugg)); + // Get the span pointing at where the `self` receiver should be. + let sm = tcx.sess.source_map(); + let self_span = method.ident.span.to(tcx + .hir() + .span_if_local(method.def_id) + .unwrap_or_else(|| sm.next_point(method.ident.span)) + .shrink_to_hi()); + let self_span = sm.span_through_char(self_span, '(').shrink_to_hi(); + return Some(MethodViolationCode::StaticMethod( + sugg, + self_span, + !sig.inputs().skip_binder().is_empty(), + )); } - let sig = tcx.fn_sig(method.def_id); - for (i, input_ty) in sig.skip_binder().inputs()[1..].iter().enumerate() { if contains_illegal_self_type_reference(tcx, trait_def_id, input_ty) { return Some(MethodViolationCode::ReferencesSelfInput(i)); diff --git a/src/test/ui/associated-consts/associated-const-in-trait.stderr b/src/test/ui/associated-consts/associated-const-in-trait.stderr index a8a8d01ed78..e9d3947543e 100644 --- a/src/test/ui/associated-consts/associated-const-in-trait.stderr +++ b/src/test/ui/associated-consts/associated-const-in-trait.stderr @@ -1,15 +1,17 @@ error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/associated-const-in-trait.rs:9:6 | -LL | trait Trait { - | ----- this trait cannot be made into an object... -LL | const N: usize; - | - ...because it contains this associated `const` -... LL | impl dyn Trait { | ^^^^^^^^^ the trait `Trait` cannot be made into an object | = help: consider moving `N` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/associated-const-in-trait.rs:6:11 + | +LL | trait Trait { + | ----- this trait cannot be made into an object... +LL | const N: usize; + | ^ ...because it contains this associated `const` error: aborting due to previous error diff --git a/src/test/ui/associated-item/issue-48027.stderr b/src/test/ui/associated-item/issue-48027.stderr index 98b545c6e0e..43e4374797c 100644 --- a/src/test/ui/associated-item/issue-48027.stderr +++ b/src/test/ui/associated-item/issue-48027.stderr @@ -1,15 +1,17 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/issue-48027.rs:6:6 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | const X: usize; - | - ...because it contains this associated `const` -... LL | impl dyn Bar {} | ^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `X` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-48027.rs:2:11 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | const X: usize; + | ^ ...because it contains this associated `const` error[E0283]: type annotations needed --> $DIR/issue-48027.rs:3:32 diff --git a/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr b/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr index cd18a013628..7b1f6e58f21 100644 --- a/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr +++ b/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr @@ -1,14 +1,17 @@ error[E0038]: the trait `NotObjectSafe` cannot be made into an object --> $DIR/coherence-impl-trait-for-trait-object-safe.rs:7:24 | -LL | trait NotObjectSafe { fn eq(&self, other: Self); } - | ------------- ---- ...because method `eq` references the `Self` type in this parameter - | | - | this trait cannot be made into an object... LL | impl NotObjectSafe for dyn NotObjectSafe { } | ^^^^^^^^^^^^^^^^^ the trait `NotObjectSafe` cannot be made into an object | = help: consider moving `eq` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/coherence-impl-trait-for-trait-object-safe.rs:6:43 + | +LL | trait NotObjectSafe { fn eq(&self, other: Self); } + | ------------- ^^^^ ...because method `eq` references the `Self` type in this parameter + | | + | this trait cannot be made into an object... error: aborting due to previous error diff --git a/src/test/ui/did_you_mean/trait-object-reference-without-parens-suggestion.stderr b/src/test/ui/did_you_mean/trait-object-reference-without-parens-suggestion.stderr index a8b160bbb2c..94efa2b3f64 100644 --- a/src/test/ui/did_you_mean/trait-object-reference-without-parens-suggestion.stderr +++ b/src/test/ui/did_you_mean/trait-object-reference-without-parens-suggestion.stderr @@ -17,6 +17,7 @@ LL | let _: &Copy + 'static; | ^^^^^ the trait `Copy` cannot be made into an object | = note: the trait cannot be made into an object because it requires `Self: Sized` + = note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> error: aborting due to 3 previous errors diff --git a/src/test/ui/error-codes/E0033-teach.stderr b/src/test/ui/error-codes/E0033-teach.stderr index f323a990455..8647eebc6be 100644 --- a/src/test/ui/error-codes/E0033-teach.stderr +++ b/src/test/ui/error-codes/E0033-teach.stderr @@ -7,15 +7,21 @@ LL | let trait_obj: &dyn SomeTrait = SomeTrait; error[E0038]: the trait `SomeTrait` cannot be made into an object --> $DIR/E0033-teach.rs:8:20 | +LL | let trait_obj: &dyn SomeTrait = SomeTrait; + | ^^^^^^^^^^^^^^ the trait `SomeTrait` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/E0033-teach.rs:4:8 + | LL | trait SomeTrait { | --------- this trait cannot be made into an object... LL | fn foo(); - | --- ...because associated function `foo` has no `self` parameter -... -LL | let trait_obj: &dyn SomeTrait = SomeTrait; - | ^^^^^^^^^^^^^^ the trait `SomeTrait` cannot be made into an object + | ^^^ ...because associated function `foo` has no `self` parameter +help: consider turning `foo` into a method by giving it a `&self` argument | -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn foo(&self); + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() where Self: Sized; | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/error-codes/E0033.stderr b/src/test/ui/error-codes/E0033.stderr index 84481ff16c0..dfc30200980 100644 --- a/src/test/ui/error-codes/E0033.stderr +++ b/src/test/ui/error-codes/E0033.stderr @@ -7,15 +7,21 @@ LL | let trait_obj: &dyn SomeTrait = SomeTrait; error[E0038]: the trait `SomeTrait` cannot be made into an object --> $DIR/E0033.rs:6:20 | +LL | let trait_obj: &dyn SomeTrait = SomeTrait; + | ^^^^^^^^^^^^^^ the trait `SomeTrait` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/E0033.rs:2:8 + | LL | trait SomeTrait { | --------- this trait cannot be made into an object... LL | fn foo(); - | --- ...because associated function `foo` has no `self` parameter -... -LL | let trait_obj: &dyn SomeTrait = SomeTrait; - | ^^^^^^^^^^^^^^ the trait `SomeTrait` cannot be made into an object + | ^^^ ...because associated function `foo` has no `self` parameter +help: consider turning `foo` into a method by giving it a `&self` argument | -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn foo(&self); + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() where Self: Sized; | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/error-codes/E0038.stderr b/src/test/ui/error-codes/E0038.stderr index 638e924b0eb..bb8a7ced7ae 100644 --- a/src/test/ui/error-codes/E0038.stderr +++ b/src/test/ui/error-codes/E0038.stderr @@ -1,15 +1,17 @@ error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/E0038.rs:5:16 | -LL | trait Trait { - | ----- this trait cannot be made into an object... -LL | fn foo(&self) -> Self; - | ---- ...because method `foo` references the `Self` type in its return type -... LL | fn call_foo(x: Box<dyn Trait>) { | ^^^^^^^^^^^^^^ the trait `Trait` cannot be made into an object | = help: consider moving `foo` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/E0038.rs:2:22 + | +LL | trait Trait { + | ----- this trait cannot be made into an object... +LL | fn foo(&self) -> Self; + | ^^^^ ...because method `foo` references the `Self` type in its return type error: aborting due to previous error diff --git a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr index e3272e8849f..a5961b5288c 100644 --- a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr +++ b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr @@ -1,26 +1,35 @@ error[E0038]: the trait `NonObjectSafe1` cannot be made into an object --> $DIR/feature-gate-object_safe_for_dispatch.rs:18:38 | +LL | fn takes_non_object_safe_ref<T>(obj: &dyn NonObjectSafe1) { + | ^^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe1` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/feature-gate-object_safe_for_dispatch.rs:4:23 + | LL | trait NonObjectSafe1: Sized {} - | -------------- ----- ...because it requires `Self: Sized` + | -------------- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... -... -LL | fn takes_non_object_safe_ref<T>(obj: &dyn NonObjectSafe1) { - | ^^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe1` cannot be made into an object error[E0038]: the trait `NonObjectSafe2` cannot be made into an object --> $DIR/feature-gate-object_safe_for_dispatch.rs:22:36 | +LL | fn return_non_object_safe_ref() -> &'static dyn NonObjectSafe2 { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe2` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/feature-gate-object_safe_for_dispatch.rs:7:8 + | LL | trait NonObjectSafe2 { | -------------- this trait cannot be made into an object... LL | fn static_fn() {} - | --------- ...because associated function `static_fn` has no `self` parameter -... -LL | fn return_non_object_safe_ref() -> &'static dyn NonObjectSafe2 { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe2` cannot be made into an object + | ^^^^^^^^^ ...because associated function `static_fn` has no `self` parameter +help: consider turning `static_fn` into a method by giving it a `&self` argument | -help: consider turning `static_fn` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn static_fn(&self) {} + | ^^^^^ +help: alternatively, consider constraining `static_fn` so it does not apply to trait objects | LL | fn static_fn() where Self: Sized {} | ^^^^^^^^^^^^^^^^^ @@ -28,39 +37,46 @@ LL | fn static_fn() where Self: Sized {} error[E0038]: the trait `NonObjectSafe3` cannot be made into an object --> $DIR/feature-gate-object_safe_for_dispatch.rs:27:35 | -LL | trait NonObjectSafe3 { - | -------------- this trait cannot be made into an object... -LL | fn foo<T>(&self); - | --- ...because method `foo` has generic type parameters -... LL | fn takes_non_object_safe_box(obj: Box<dyn NonObjectSafe3>) { | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe3` cannot be made into an object | = help: consider moving `foo` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/feature-gate-object_safe_for_dispatch.rs:11:8 + | +LL | trait NonObjectSafe3 { + | -------------- this trait cannot be made into an object... +LL | fn foo<T>(&self); + | ^^^ ...because method `foo` has generic type parameters error[E0038]: the trait `NonObjectSafe4` cannot be made into an object --> $DIR/feature-gate-object_safe_for_dispatch.rs:31:35 | -LL | trait NonObjectSafe4 { - | -------------- this trait cannot be made into an object... -LL | fn foo(&self, &Self); - | ----- ...because method `foo` references the `Self` type in this parameter -... LL | fn return_non_object_safe_rc() -> std::rc::Rc<dyn NonObjectSafe4> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe4` cannot be made into an object | = help: consider moving `foo` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/feature-gate-object_safe_for_dispatch.rs:15:19 + | +LL | trait NonObjectSafe4 { + | -------------- this trait cannot be made into an object... +LL | fn foo(&self, &Self); + | ^^^^^ ...because method `foo` references the `Self` type in this parameter error[E0038]: the trait `NonObjectSafe1` cannot be made into an object --> $DIR/feature-gate-object_safe_for_dispatch.rs:38:16 | +LL | impl Trait for dyn NonObjectSafe1 {} + | ^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe1` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/feature-gate-object_safe_for_dispatch.rs:4:23 + | LL | trait NonObjectSafe1: Sized {} - | -------------- ----- ...because it requires `Self: Sized` + | -------------- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... -... -LL | impl Trait for dyn NonObjectSafe1 {} - | ^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe1` cannot be made into an object error: aborting due to 5 previous errors diff --git a/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr b/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr index 9df5188bbdd..2d58b12bfb1 100644 --- a/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr +++ b/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr @@ -1,15 +1,21 @@ error[E0038]: the trait `NotObjectSafe` cannot be made into an object --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:21:13 | +LL | fn car() -> dyn NotObjectSafe { + | ^^^^^^^^^^^^^^^^^ the trait `NotObjectSafe` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:3:8 + | LL | trait NotObjectSafe { | ------------- this trait cannot be made into an object... LL | fn foo() -> Self; - | --- ...because associated function `foo` has no `self` parameter -... -LL | fn car() -> dyn NotObjectSafe { - | ^^^^^^^^^^^^^^^^^ the trait `NotObjectSafe` cannot be made into an object + | ^^^ ...because associated function `foo` has no `self` parameter +help: consider turning `foo` into a method by giving it a `&self` argument | -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn foo(&self) -> Self; + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() -> Self where Self: Sized; | ^^^^^^^^^^^^^^^^^ @@ -17,15 +23,21 @@ LL | fn foo() -> Self where Self: Sized; error[E0038]: the trait `NotObjectSafe` cannot be made into an object --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:28:13 | +LL | fn cat() -> Box<dyn NotObjectSafe> { + | ^^^^^^^^^^^^^^^^^^^^^^ the trait `NotObjectSafe` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:3:8 + | LL | trait NotObjectSafe { | ------------- this trait cannot be made into an object... LL | fn foo() -> Self; - | --- ...because associated function `foo` has no `self` parameter -... -LL | fn cat() -> Box<dyn NotObjectSafe> { - | ^^^^^^^^^^^^^^^^^^^^^^ the trait `NotObjectSafe` cannot be made into an object + | ^^^ ...because associated function `foo` has no `self` parameter +help: consider turning `foo` into a method by giving it a `&self` argument | -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn foo(&self) -> Self; + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() -> Self where Self: Sized; | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/issues/issue-18959.stderr b/src/test/ui/issues/issue-18959.stderr index b3ba7aecad0..2be8c6188bd 100644 --- a/src/test/ui/issues/issue-18959.stderr +++ b/src/test/ui/issues/issue-18959.stderr @@ -1,15 +1,17 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/issue-18959.rs:11:11 | -LL | pub trait Foo { fn foo<T>(&self, ext_thing: &T); } - | --- ...because method `foo` has generic type parameters -LL | pub trait Bar: Foo { } - | --- this trait cannot be made into an object... -... LL | fn foo(b: &dyn Bar) { | ^^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `foo` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-18959.rs:1:20 + | +LL | pub trait Foo { fn foo<T>(&self, ext_thing: &T); } + | ^^^ ...because method `foo` has generic type parameters +LL | pub trait Bar: Foo { } + | --- this trait cannot be made into an object... error: aborting due to previous error diff --git a/src/test/ui/issues/issue-19380.stderr b/src/test/ui/issues/issue-19380.stderr index 63f0701974b..73e329f8d95 100644 --- a/src/test/ui/issues/issue-19380.stderr +++ b/src/test/ui/issues/issue-19380.stderr @@ -1,15 +1,21 @@ error[E0038]: the trait `Qiz` cannot be made into an object --> $DIR/issue-19380.rs:11:9 | +LL | foos: &'static [&'static (dyn Qiz + 'static)] + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Qiz` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-19380.rs:2:6 + | LL | trait Qiz { | --- this trait cannot be made into an object... LL | fn qiz(); - | --- ...because associated function `qiz` has no `self` parameter -... -LL | foos: &'static [&'static (dyn Qiz + 'static)] - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Qiz` cannot be made into an object + | ^^^ ...because associated function `qiz` has no `self` parameter +help: consider turning `qiz` into a method by giving it a `&self` argument | -help: consider turning `qiz` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn qiz(&self); + | ^^^^^ +help: alternatively, consider constraining `qiz` so it does not apply to trait objects | LL | fn qiz() where Self: Sized; | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/issues/issue-19538.stderr b/src/test/ui/issues/issue-19538.stderr index 71a013248cf..c2421970ca2 100644 --- a/src/test/ui/issues/issue-19538.stderr +++ b/src/test/ui/issues/issue-19538.stderr @@ -1,30 +1,34 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/issue-19538.rs:17:15 | -LL | fn foo<T>(&self, val: T); - | --- ...because method `foo` has generic type parameters -... -LL | trait Bar: Foo { } - | --- this trait cannot be made into an object... -... LL | let test: &mut dyn Bar = &mut thing; | ^^^^^^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `foo` to another trait - -error[E0038]: the trait `Bar` cannot be made into an object - --> $DIR/issue-19538.rs:17:30 +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-19538.rs:2:8 | LL | fn foo<T>(&self, val: T); - | --- ...because method `foo` has generic type parameters + | ^^^ ...because method `foo` has generic type parameters ... LL | trait Bar: Foo { } | --- this trait cannot be made into an object... -... + +error[E0038]: the trait `Bar` cannot be made into an object + --> $DIR/issue-19538.rs:17:30 + | LL | let test: &mut dyn Bar = &mut thing; | ^^^^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `foo` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-19538.rs:2:8 + | +LL | fn foo<T>(&self, val: T); + | ^^^ ...because method `foo` has generic type parameters +... +LL | trait Bar: Foo { } + | --- this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&mut dyn Bar>` for `&mut Thing` = note: required by cast to type `&mut dyn Bar` diff --git a/src/test/ui/issues/issue-20692.stderr b/src/test/ui/issues/issue-20692.stderr index 0badf66ba7d..241e1b51793 100644 --- a/src/test/ui/issues/issue-20692.stderr +++ b/src/test/ui/issues/issue-20692.stderr @@ -1,27 +1,32 @@ error[E0038]: the trait `Array` cannot be made into an object --> $DIR/issue-20692.rs:7:5 | +LL | &dyn Array; + | ^^^^^^^^^^ the trait `Array` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-20692.rs:1:14 + | LL | trait Array: Sized + Copy {} - | ----- ----- ---- ...because it requires `Self: Sized` + | ----- ^^^^^ ^^^^ ...because it requires `Self: Sized` | | | | | ...because it requires `Self: Sized` | this trait cannot be made into an object... -... -LL | &dyn Array; - | ^^^^^^^^^^ the trait `Array` cannot be made into an object error[E0038]: the trait `Array` cannot be made into an object --> $DIR/issue-20692.rs:4:13 | +LL | let _ = x + | ^ the trait `Array` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-20692.rs:1:14 + | LL | trait Array: Sized + Copy {} - | ----- ----- ---- ...because it requires `Self: Sized` + | ----- ^^^^^ ^^^^ ...because it requires `Self: Sized` | | | | | ...because it requires `Self: Sized` | this trait cannot be made into an object... -... -LL | let _ = x - | ^ the trait `Array` cannot be made into an object - | = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Array>` for `&T` = note: required by cast to type `&dyn Array` diff --git a/src/test/ui/issues/issue-26056.stderr b/src/test/ui/issues/issue-26056.stderr index be438ef9ac7..ba1ec67dfca 100644 --- a/src/test/ui/issues/issue-26056.stderr +++ b/src/test/ui/issues/issue-26056.stderr @@ -1,13 +1,16 @@ error[E0038]: the trait `Map` cannot be made into an object --> $DIR/issue-26056.rs:20:13 | +LL | as &dyn Map<Key=u32,MapValue=u32>; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Map` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-26056.rs:9:12 + | LL | trait Map: MapLookup<<Self as Map>::Key> { - | --- ----------------------------- ...because it uses `Self` as a type parameter in this + | --- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...because it uses `Self` as a type parameter in this | | | this trait cannot be made into an object... -... -LL | as &dyn Map<Key=u32,MapValue=u32>; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Map` cannot be made into an object error: aborting due to previous error diff --git a/src/test/ui/issues/issue-28576.stderr b/src/test/ui/issues/issue-28576.stderr index 658199003c1..726982d1772 100644 --- a/src/test/ui/issues/issue-28576.stderr +++ b/src/test/ui/issues/issue-28576.stderr @@ -1,16 +1,19 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/issue-28576.rs:7:12 | -LL | pub trait Bar: Foo<Assoc=()> { - | --- ------------- - | | | | - | | | ...because it uses `Self` as a type parameter in this - | | ...because it uses `Self` as a type parameter in this - | this trait cannot be made into an object... -LL | fn new(&self, b: & LL | / dyn Bar LL | | <Assoc=()> | |________________________^ the trait `Bar` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-28576.rs:5:16 + | +LL | pub trait Bar: Foo<Assoc=()> { + | --- ^^^^^^^^^^^^^ + | | | | + | | | ...because it uses `Self` as a type parameter in this + | | ...because it uses `Self` as a type parameter in this + | this trait cannot be made into an object... error: aborting due to previous error diff --git a/src/test/ui/issues/issue-38404.stderr b/src/test/ui/issues/issue-38404.stderr index 50c5195dc93..b814f0a3273 100644 --- a/src/test/ui/issues/issue-38404.stderr +++ b/src/test/ui/issues/issue-38404.stderr @@ -1,12 +1,16 @@ error[E0038]: the trait `B` cannot be made into an object --> $DIR/issue-38404.rs:3:15 | +LL | trait C<T>: A<dyn B<T, Output=usize>> {} + | ^^^^^^^^^^^^^^^^^^^^^^ the trait `B` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-38404.rs:1:13 + | LL | trait A<T>: std::ops::Add<Self> + Sized {} - | ------------------- ...because it uses `Self` as a type parameter in this + | ^^^^^^^^^^^^^^^^^^^ ...because it uses `Self` as a type parameter in this LL | trait B<T>: A<T> {} | - this trait cannot be made into an object... -LL | trait C<T>: A<dyn B<T, Output=usize>> {} - | ^^^^^^^^^^^^^^^^^^^^^^ the trait `B` cannot be made into an object error: aborting due to previous error diff --git a/src/test/ui/issues/issue-38604.stderr b/src/test/ui/issues/issue-38604.stderr index 39a62b81c6c..87c873ae35f 100644 --- a/src/test/ui/issues/issue-38604.stderr +++ b/src/test/ui/issues/issue-38604.stderr @@ -1,25 +1,30 @@ error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/issue-38604.rs:14:13 | +LL | let _f: Box<dyn Foo> = + | ^^^^^^^^^^^^ the trait `Foo` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-38604.rs:2:22 + | LL | trait Foo where u32: Q<Self> { - | --- ------- ...because it uses `Self` as a type parameter in this + | --- ^^^^^^^ ...because it uses `Self` as a type parameter in this | | | this trait cannot be made into an object... -... -LL | let _f: Box<dyn Foo> = - | ^^^^^^^^^^^^ the trait `Foo` cannot be made into an object error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/issue-38604.rs:15:9 | -LL | trait Foo where u32: Q<Self> { - | --- ------- ...because it uses `Self` as a type parameter in this - | | - | this trait cannot be made into an object... -... LL | Box::new(()); | ^^^^^^^^^^^^ the trait `Foo` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-38604.rs:2:22 + | +LL | trait Foo where u32: Q<Self> { + | --- ^^^^^^^ ...because it uses `Self` as a type parameter in this + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn Foo>>` for `Box<()>` = note: required by cast to type `Box<dyn Foo>` diff --git a/src/test/ui/issues/issue-50781.stderr b/src/test/ui/issues/issue-50781.stderr index 03e3a7f227a..93bd951d3fa 100644 --- a/src/test/ui/issues/issue-50781.stderr +++ b/src/test/ui/issues/issue-50781.stderr @@ -1,10 +1,8 @@ error: the trait `X` cannot be made into an object --> $DIR/issue-50781.rs:6:8 | -LL | trait X { - | - this trait cannot be made into an object... LL | fn foo(&self) where Self: Trait; - | ^^^ ...because method `foo` references the `Self` type in its `where` clause + | ^^^ | note: the lint level is defined here --> $DIR/issue-50781.rs:1:9 @@ -13,6 +11,13 @@ LL | #![deny(where_clauses_object_safety)] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #51443 <https://github.com/rust-lang/rust/issues/51443> +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-50781.rs:6:8 + | +LL | trait X { + | - this trait cannot be made into an object... +LL | fn foo(&self) where Self: Trait; + | ^^^ ...because method `foo` references the `Self` type in its `where` clause = help: consider moving `foo` to another trait error: aborting due to previous error diff --git a/src/test/ui/kindck/kindck-inherited-copy-bound.curr.stderr b/src/test/ui/kindck/kindck-inherited-copy-bound.curr.stderr index a6fd44d1743..3ec3900d883 100644 --- a/src/test/ui/kindck/kindck-inherited-copy-bound.curr.stderr +++ b/src/test/ui/kindck/kindck-inherited-copy-bound.curr.stderr @@ -12,25 +12,30 @@ LL | take_param(&x); error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/kindck-inherited-copy-bound.rs:28:19 | +LL | let z = &x as &dyn Foo; + | ^^^^^^^^ the trait `Foo` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/kindck-inherited-copy-bound.rs:10:13 + | LL | trait Foo : Copy { - | --- ---- ...because it requires `Self: Sized` + | --- ^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... -... -LL | let z = &x as &dyn Foo; - | ^^^^^^^^ the trait `Foo` cannot be made into an object error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/kindck-inherited-copy-bound.rs:28:13 | -LL | trait Foo : Copy { - | --- ---- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | let z = &x as &dyn Foo; | ^^ the trait `Foo` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/kindck-inherited-copy-bound.rs:10:13 + | +LL | trait Foo : Copy { + | --- ^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Foo>` for `&Box<{integer}>` = note: required by cast to type `&dyn Foo` diff --git a/src/test/ui/kindck/kindck-inherited-copy-bound.object_safe_for_dispatch.stderr b/src/test/ui/kindck/kindck-inherited-copy-bound.object_safe_for_dispatch.stderr index bc7448a05e8..14ef610685e 100644 --- a/src/test/ui/kindck/kindck-inherited-copy-bound.object_safe_for_dispatch.stderr +++ b/src/test/ui/kindck/kindck-inherited-copy-bound.object_safe_for_dispatch.stderr @@ -12,14 +12,16 @@ LL | take_param(&x); error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/kindck-inherited-copy-bound.rs:28:13 | -LL | trait Foo : Copy { - | --- ---- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | let z = &x as &dyn Foo; | ^^ the trait `Foo` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/kindck-inherited-copy-bound.rs:10:13 + | +LL | trait Foo : Copy { + | --- ^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Foo>` for `&Box<i32>` = note: required by cast to type `&dyn Foo` diff --git a/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr b/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr index 890acde35c4..ed7200bc620 100644 --- a/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr +++ b/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr @@ -1,15 +1,17 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-associated-consts.rs:12:30 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | const X: usize; - | - ...because it contains this associated `const` -... LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar { | ^^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `X` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-associated-consts.rs:9:11 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | const X: usize; + | ^ ...because it contains this associated `const` error: aborting due to previous error diff --git a/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr index c32038b5a27..97310adee9b 100644 --- a/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr +++ b/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr @@ -1,15 +1,17 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-associated-consts.rs:14:5 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | const X: usize; - | - ...because it contains this associated `const` -... LL | t | ^ the trait `Bar` cannot be made into an object | = help: consider moving `X` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-associated-consts.rs:9:11 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | const X: usize; + | ^ ...because it contains this associated `const` = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` diff --git a/src/test/ui/object-safety/object-safety-bounds.stderr b/src/test/ui/object-safety/object-safety-bounds.stderr index af454830863..3f8ed31f1ae 100644 --- a/src/test/ui/object-safety/object-safety-bounds.stderr +++ b/src/test/ui/object-safety/object-safety-bounds.stderr @@ -1,13 +1,16 @@ error[E0038]: the trait `X` cannot be made into an object --> $DIR/object-safety-bounds.rs:7:11 | +LL | fn f() -> Box<dyn X<U = u32>> { + | ^^^^^^^^^^^^^^^^^^^ the trait `X` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-bounds.rs:4:13 + | LL | trait X { | - this trait cannot be made into an object... LL | type U: PartialEq<Self>; - | --------------- ...because it uses `Self` as a type parameter in this -... -LL | fn f() -> Box<dyn X<U = u32>> { - | ^^^^^^^^^^^^^^^^^^^ the trait `X` cannot be made into an object + | ^^^^^^^^^^^^^^^ ...because it uses `Self` as a type parameter in this error: aborting due to previous error diff --git a/src/test/ui/object-safety/object-safety-generics.curr.stderr b/src/test/ui/object-safety/object-safety-generics.curr.stderr index 9e70abbd32f..f18ac4c813f 100644 --- a/src/test/ui/object-safety/object-safety-generics.curr.stderr +++ b/src/test/ui/object-safety/object-safety-generics.curr.stderr @@ -1,28 +1,32 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-generics.rs:18:30 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | fn bar<T>(&self, t: T); - | --- ...because method `bar` has generic type parameters -... LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar { | ^^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `bar` to another trait - -error[E0038]: the trait `Bar` cannot be made into an object - --> $DIR/object-safety-generics.rs:24:39 +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-generics.rs:10:8 | LL | trait Bar { | --- this trait cannot be made into an object... LL | fn bar<T>(&self, t: T); - | --- ...because method `bar` has generic type parameters -... + | ^^^ ...because method `bar` has generic type parameters + +error[E0038]: the trait `Bar` cannot be made into an object + --> $DIR/object-safety-generics.rs:24:39 + | LL | fn make_bar_explicit<T:Bar>(t: &T) -> &dyn Bar { | ^^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `bar` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-generics.rs:10:8 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | fn bar<T>(&self, t: T); + | ^^^ ...because method `bar` has generic type parameters error: aborting due to 2 previous errors diff --git a/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr index 7c104fa158d..62e1dc89543 100644 --- a/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr +++ b/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr @@ -1,30 +1,34 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-generics.rs:20:5 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | fn bar<T>(&self, t: T); - | --- ...because method `bar` has generic type parameters -... LL | t | ^ the trait `Bar` cannot be made into an object | = help: consider moving `bar` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-generics.rs:10:8 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | fn bar<T>(&self, t: T); + | ^^^ ...because method `bar` has generic type parameters = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-generics.rs:26:5 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | fn bar<T>(&self, t: T); - | --- ...because method `bar` has generic type parameters -... LL | t as &dyn Bar | ^ the trait `Bar` cannot be made into an object | = help: consider moving `bar` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-generics.rs:10:8 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | fn bar<T>(&self, t: T); + | ^^^ ...because method `bar` has generic type parameters = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` diff --git a/src/test/ui/object-safety/object-safety-issue-22040.stderr b/src/test/ui/object-safety/object-safety-issue-22040.stderr index fe9ca5b6fa4..63b45e25884 100644 --- a/src/test/ui/object-safety/object-safety-issue-22040.stderr +++ b/src/test/ui/object-safety/object-safety-issue-22040.stderr @@ -1,13 +1,16 @@ error[E0038]: the trait `Expr` cannot be made into an object --> $DIR/object-safety-issue-22040.rs:12:23 | +LL | elements: Vec<Box<dyn Expr + 'x>>, + | ^^^^^^^^^^^^^ the trait `Expr` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-issue-22040.rs:5:21 + | LL | trait Expr: Debug + PartialEq { - | ---- --------- ...because it uses `Self` as a type parameter in this + | ---- ^^^^^^^^^ ...because it uses `Self` as a type parameter in this | | | this trait cannot be made into an object... -... -LL | elements: Vec<Box<dyn Expr + 'x>>, - | ^^^^^^^^^^^^^ the trait `Expr` cannot be made into an object error: aborting due to previous error diff --git a/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr b/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr index 4dbb27b425b..2d8de311930 100644 --- a/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr +++ b/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr @@ -1,28 +1,32 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-mentions-Self.rs:22:30 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | fn bar(&self, x: &Self); - | ----- ...because method `bar` references the `Self` type in this parameter -... LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar { | ^^^^^^^^ the trait `Bar` cannot be made into an object | = help: consider moving `bar` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-mentions-Self.rs:11:22 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | fn bar(&self, x: &Self); + | ^^^^^ ...because method `bar` references the `Self` type in this parameter error[E0038]: the trait `Baz` cannot be made into an object --> $DIR/object-safety-mentions-Self.rs:28:30 | -LL | trait Baz { - | --- this trait cannot be made into an object... -LL | fn baz(&self) -> Self; - | ---- ...because method `baz` references the `Self` type in its return type -... LL | fn make_baz<T:Baz>(t: &T) -> &dyn Baz { | ^^^^^^^^ the trait `Baz` cannot be made into an object | = help: consider moving `baz` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-mentions-Self.rs:15:22 + | +LL | trait Baz { + | --- this trait cannot be made into an object... +LL | fn baz(&self) -> Self; + | ^^^^ ...because method `baz` references the `Self` type in its return type error: aborting due to 2 previous errors diff --git a/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr index ced26889ba0..3b26ce4eac4 100644 --- a/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr +++ b/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr @@ -1,30 +1,34 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-mentions-Self.rs:24:5 | -LL | trait Bar { - | --- this trait cannot be made into an object... -LL | fn bar(&self, x: &Self); - | ----- ...because method `bar` references the `Self` type in this parameter -... LL | t | ^ the trait `Bar` cannot be made into an object | = help: consider moving `bar` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-mentions-Self.rs:11:22 + | +LL | trait Bar { + | --- this trait cannot be made into an object... +LL | fn bar(&self, x: &Self); + | ^^^^^ ...because method `bar` references the `Self` type in this parameter = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` error[E0038]: the trait `Baz` cannot be made into an object --> $DIR/object-safety-mentions-Self.rs:30:5 | -LL | trait Baz { - | --- this trait cannot be made into an object... -LL | fn baz(&self) -> Self; - | ---- ...because method `baz` references the `Self` type in its return type -... LL | t | ^ the trait `Baz` cannot be made into an object | = help: consider moving `baz` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-mentions-Self.rs:15:22 + | +LL | trait Baz { + | --- this trait cannot be made into an object... +LL | fn baz(&self) -> Self; + | ^^^^ ...because method `baz` references the `Self` type in its return type = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Baz>` for `&T` = note: required by cast to type `&dyn Baz` diff --git a/src/test/ui/object-safety/object-safety-no-static.curr.stderr b/src/test/ui/object-safety/object-safety-no-static.curr.stderr index f878cf8b462..5b42cb55b84 100644 --- a/src/test/ui/object-safety/object-safety-no-static.curr.stderr +++ b/src/test/ui/object-safety/object-safety-no-static.curr.stderr @@ -1,15 +1,21 @@ error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/object-safety-no-static.rs:12:18 | +LL | fn diverges() -> Box<dyn Foo> { + | ^^^^^^^^^^^^ the trait `Foo` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-no-static.rs:9:8 + | LL | trait Foo { | --- this trait cannot be made into an object... LL | fn foo() {} - | --- ...because associated function `foo` has no `self` parameter -... -LL | fn diverges() -> Box<dyn Foo> { - | ^^^^^^^^^^^^ the trait `Foo` cannot be made into an object + | ^^^ ...because associated function `foo` has no `self` parameter +help: consider turning `foo` into a method by giving it a `&self` argument | -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn foo(&self) {} + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() where Self: Sized {} | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/object-safety/object-safety-no-static.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-no-static.object_safe_for_dispatch.stderr index 8e920697d8f..5bff24224af 100644 --- a/src/test/ui/object-safety/object-safety-no-static.object_safe_for_dispatch.stderr +++ b/src/test/ui/object-safety/object-safety-no-static.object_safe_for_dispatch.stderr @@ -1,17 +1,23 @@ error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/object-safety-no-static.rs:22:27 | -LL | trait Foo { - | --- this trait cannot be made into an object... -LL | fn foo() {} - | --- ...because associated function `foo` has no `self` parameter -... LL | let b: Box<dyn Foo> = Box::new(Bar); | ^^^^^^^^^^^^^ the trait `Foo` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-no-static.rs:9:8 + | +LL | trait Foo { + | --- this trait cannot be made into an object... +LL | fn foo() {} + | ^^^ ...because associated function `foo` has no `self` parameter = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn Foo>>` for `Box<Bar>` = note: required by cast to type `Box<dyn Foo>` -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +help: consider turning `foo` into a method by giving it a `&self` argument + | +LL | fn foo(&self) {} + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() where Self: Sized {} | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/object-safety/object-safety-sized-2.curr.stderr b/src/test/ui/object-safety/object-safety-sized-2.curr.stderr index 2f605d8e904..eb1fa261636 100644 --- a/src/test/ui/object-safety/object-safety-sized-2.curr.stderr +++ b/src/test/ui/object-safety/object-safety-sized-2.curr.stderr @@ -1,13 +1,16 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-sized-2.rs:14:30 | +LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar { + | ^^^^^^^^ the trait `Bar` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-sized-2.rs:9:18 + | LL | trait Bar | --- this trait cannot be made into an object... LL | where Self : Sized - | ----- ...because it requires `Self: Sized` -... -LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar { - | ^^^^^^^^ the trait `Bar` cannot be made into an object + | ^^^^^ ...because it requires `Self: Sized` error: aborting due to previous error diff --git a/src/test/ui/object-safety/object-safety-sized-2.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-sized-2.object_safe_for_dispatch.stderr index cc0463f5d87..eb03763f3e7 100644 --- a/src/test/ui/object-safety/object-safety-sized-2.object_safe_for_dispatch.stderr +++ b/src/test/ui/object-safety/object-safety-sized-2.object_safe_for_dispatch.stderr @@ -1,14 +1,16 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-sized-2.rs:16:5 | -LL | trait Bar - | --- this trait cannot be made into an object... -LL | where Self : Sized - | ----- ...because it requires `Self: Sized` -... LL | t | ^ the trait `Bar` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-sized-2.rs:9:18 + | +LL | trait Bar + | --- this trait cannot be made into an object... +LL | where Self : Sized + | ^^^^^ ...because it requires `Self: Sized` = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` diff --git a/src/test/ui/object-safety/object-safety-sized.curr.stderr b/src/test/ui/object-safety/object-safety-sized.curr.stderr index 54f65c43d9c..fa07501b118 100644 --- a/src/test/ui/object-safety/object-safety-sized.curr.stderr +++ b/src/test/ui/object-safety/object-safety-sized.curr.stderr @@ -1,13 +1,16 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-sized.rs:12:30 | +LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar { + | ^^^^^^^^ the trait `Bar` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-sized.rs:8:13 + | LL | trait Bar : Sized { - | --- ----- ...because it requires `Self: Sized` + | --- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... -... -LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar { - | ^^^^^^^^ the trait `Bar` cannot be made into an object error: aborting due to previous error diff --git a/src/test/ui/object-safety/object-safety-sized.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-sized.object_safe_for_dispatch.stderr index aceacac2db3..9ce6ae8022c 100644 --- a/src/test/ui/object-safety/object-safety-sized.object_safe_for_dispatch.stderr +++ b/src/test/ui/object-safety/object-safety-sized.object_safe_for_dispatch.stderr @@ -1,14 +1,16 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-sized.rs:14:5 | -LL | trait Bar : Sized { - | --- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | t | ^ the trait `Bar` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-sized.rs:8:13 + | +LL | trait Bar : Sized { + | --- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` diff --git a/src/test/ui/object-safety/object-safety-supertrait-mentions-Self.stderr b/src/test/ui/object-safety/object-safety-supertrait-mentions-Self.stderr index ef7f6bacd12..57435028043 100644 --- a/src/test/ui/object-safety/object-safety-supertrait-mentions-Self.stderr +++ b/src/test/ui/object-safety/object-safety-supertrait-mentions-Self.stderr @@ -1,13 +1,16 @@ error[E0038]: the trait `Baz` cannot be made into an object --> $DIR/object-safety-supertrait-mentions-Self.rs:15:31 | +LL | fn make_baz<T:Baz>(t: &T) -> &dyn Baz { + | ^^^^^^^ the trait `Baz` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-safety-supertrait-mentions-Self.rs:8:13 + | LL | trait Baz : Bar<Self> { - | --- --------- ...because it uses `Self` as a type parameter in this + | --- ^^^^^^^^^ ...because it uses `Self` as a type parameter in this | | | this trait cannot be made into an object... -... -LL | fn make_baz<T:Baz>(t: &T) -> &dyn Baz { - | ^^^^^^^ the trait `Baz` cannot be made into an object error: aborting due to previous error diff --git a/src/test/ui/resolve/issue-3907-2.stderr b/src/test/ui/resolve/issue-3907-2.stderr index bd6e9d59502..b8a7f3b9742 100644 --- a/src/test/ui/resolve/issue-3907-2.stderr +++ b/src/test/ui/resolve/issue-3907-2.stderr @@ -3,11 +3,12 @@ error[E0038]: the trait `issue_3907::Foo` cannot be made into an object | LL | fn bar(_x: Foo) {} | ^^^ the trait `issue_3907::Foo` cannot be made into an object - | - ::: $DIR/auxiliary/issue-3907.rs:2:8 + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/auxiliary/issue-3907.rs:2:8 | LL | fn bar(); - | --- the trait cannot be made into an object because associated function `bar` has no `self` parameter + | ^^^ the trait cannot be made into an object because associated function `bar` has no `self` parameter error: aborting due to previous error diff --git a/src/test/ui/self/arbitrary-self-types-not-object-safe.curr.stderr b/src/test/ui/self/arbitrary-self-types-not-object-safe.curr.stderr index 85da2c6eeb0..4ea5dae2ec9 100644 --- a/src/test/ui/self/arbitrary-self-types-not-object-safe.curr.stderr +++ b/src/test/ui/self/arbitrary-self-types-not-object-safe.curr.stderr @@ -1,31 +1,36 @@ error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/arbitrary-self-types-not-object-safe.rs:33:32 | -LL | trait Foo { - | --- this trait cannot be made into an object... LL | fn foo(self: &Rc<Self>) -> usize; - | --------- - | | - | ...because method `foo`'s `self` parameter cannot be dispatched on - | help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self` + | --------- help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self` ... LL | let x = Rc::new(5usize) as Rc<dyn Foo>; | ^^^^^^^^^^^ the trait `Foo` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/arbitrary-self-types-not-object-safe.rs:8:18 + | +LL | trait Foo { + | --- this trait cannot be made into an object... +LL | fn foo(self: &Rc<Self>) -> usize; + | ^^^^^^^^^ ...because method `foo`'s `self` parameter cannot be dispatched on error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/arbitrary-self-types-not-object-safe.rs:33:13 | -LL | trait Foo { - | --- this trait cannot be made into an object... LL | fn foo(self: &Rc<Self>) -> usize; - | --------- - | | - | ...because method `foo`'s `self` parameter cannot be dispatched on - | help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self` + | --------- help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self` ... LL | let x = Rc::new(5usize) as Rc<dyn Foo>; | ^^^^^^^^^^^^^^^ the trait `Foo` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/arbitrary-self-types-not-object-safe.rs:8:18 + | +LL | trait Foo { + | --- this trait cannot be made into an object... +LL | fn foo(self: &Rc<Self>) -> usize; + | ^^^^^^^^^ ...because method `foo`'s `self` parameter cannot be dispatched on = note: required because of the requirements on the impl of `CoerceUnsized<Rc<dyn Foo>>` for `Rc<usize>` = note: required by cast to type `Rc<dyn Foo>` diff --git a/src/test/ui/self/arbitrary-self-types-not-object-safe.object_safe_for_dispatch.stderr b/src/test/ui/self/arbitrary-self-types-not-object-safe.object_safe_for_dispatch.stderr index c4cde2c3561..9d658e7ac41 100644 --- a/src/test/ui/self/arbitrary-self-types-not-object-safe.object_safe_for_dispatch.stderr +++ b/src/test/ui/self/arbitrary-self-types-not-object-safe.object_safe_for_dispatch.stderr @@ -1,17 +1,19 @@ error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/arbitrary-self-types-not-object-safe.rs:33:13 | -LL | trait Foo { - | --- this trait cannot be made into an object... LL | fn foo(self: &Rc<Self>) -> usize; - | --------- - | | - | ...because method `foo`'s `self` parameter cannot be dispatched on - | help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self` + | --------- help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self` ... LL | let x = Rc::new(5usize) as Rc<dyn Foo>; | ^^^^^^^^^^^^^^^ the trait `Foo` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/arbitrary-self-types-not-object-safe.rs:8:18 + | +LL | trait Foo { + | --- this trait cannot be made into an object... +LL | fn foo(self: &Rc<Self>) -> usize; + | ^^^^^^^^^ ...because method `foo`'s `self` parameter cannot be dispatched on = note: required because of the requirements on the impl of `CoerceUnsized<Rc<dyn Foo>>` for `Rc<usize>` = note: required by cast to type `Rc<dyn Foo>` diff --git a/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr b/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr index c3cfad70bf4..94f8398a786 100644 --- a/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr +++ b/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr @@ -1,29 +1,34 @@ error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/object-unsafe-trait-references-self.rs:6:11 | -LL | trait Trait { - | ----- this trait cannot be made into an object... -LL | fn baz(&self, _: Self) {} - | ---- ...because method `baz` references the `Self` type in this parameter -LL | fn bat(&self) -> Self {} - | ---- ...because method `bat` references the `Self` type in its return type -... LL | fn bar(x: &dyn Trait) {} | ^^^^^^^^^^ the trait `Trait` cannot be made into an object | = help: consider moving `baz` to another trait = help: consider moving `bat` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-unsafe-trait-references-self.rs:2:22 + | +LL | trait Trait { + | ----- this trait cannot be made into an object... +LL | fn baz(&self, _: Self) {} + | ^^^^ ...because method `baz` references the `Self` type in this parameter +LL | fn bat(&self) -> Self {} + | ^^^^ ...because method `bat` references the `Self` type in its return type error[E0038]: the trait `Other` cannot be made into an object --> $DIR/object-unsafe-trait-references-self.rs:10:11 | +LL | fn foo(x: &dyn Other) {} + | ^^^^^^^^^^ the trait `Other` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-unsafe-trait-references-self.rs:8:14 + | LL | trait Other: Sized {} - | ----- ----- ...because it requires `Self: Sized` + | ----- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... -LL | -LL | fn foo(x: &dyn Other) {} - | ^^^^^^^^^^ the trait `Other` cannot be made into an object error: aborting due to 2 previous errors diff --git a/src/test/ui/suggestions/object-unsafe-trait-should-use-self.stderr b/src/test/ui/suggestions/object-unsafe-trait-should-use-self.stderr index 58be59602b9..ee44cec318b 100644 --- a/src/test/ui/suggestions/object-unsafe-trait-should-use-self.stderr +++ b/src/test/ui/suggestions/object-unsafe-trait-should-use-self.stderr @@ -14,12 +14,16 @@ LL | fn f(a: Self) -> Self; error[E0038]: the trait `A` cannot be made into an object --> $DIR/object-unsafe-trait-should-use-self.rs:3:13 | +LL | fn f(a: A) -> A; + | ^ the trait `A` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-unsafe-trait-should-use-self.rs:2:10 + | LL | trait A: Sized { - | - ----- ...because it requires `Self: Sized` + | - ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... -LL | fn f(a: A) -> A; - | ^ the trait `A` cannot be made into an object error: associated item referring to unboxed trait object for its own trait --> $DIR/object-unsafe-trait-should-use-self.rs:8:13 @@ -37,14 +41,21 @@ LL | fn f(a: Self) -> Self; error[E0038]: the trait `B` cannot be made into an object --> $DIR/object-unsafe-trait-should-use-self.rs:8:13 | +LL | fn f(a: B) -> B; + | ^ the trait `B` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-unsafe-trait-should-use-self.rs:8:8 + | LL | trait B { | - this trait cannot be made into an object... LL | fn f(a: B) -> B; - | - ^ the trait `B` cannot be made into an object - | | - | ...because associated function `f` has no `self` parameter + | ^ ...because associated function `f` has no `self` parameter +help: consider turning `f` into a method by giving it a `&self` argument | -help: consider turning `f` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn f(&self, a: B) -> B; + | ^^^^^^ +help: alternatively, consider constraining `f` so it does not apply to trait objects | LL | fn f(a: B) -> B where Self: Sized; | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.fixed b/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.fixed index c4b8960b65e..73bb6725f5a 100644 --- a/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.fixed +++ b/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.fixed @@ -2,7 +2,7 @@ #![allow(unused_variables, dead_code)] trait Trait { - fn foo() where Self: Other, Self: Sized, { } + fn foo(&self) where Self: Other, Self: Sized, { } fn bar(self: &Self) {} //~ ERROR invalid `self` parameter type } diff --git a/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr b/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr index 6466a768ecb..3ea9a516140 100644 --- a/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr +++ b/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr @@ -1,17 +1,23 @@ error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/object-unsafe-trait-should-use-where-sized.rs:9:11 | +LL | fn bar(x: &dyn Trait) {} + | ^^^^^^^^^^ the trait `Trait` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/object-unsafe-trait-should-use-where-sized.rs:5:8 + | LL | trait Trait { | ----- this trait cannot be made into an object... LL | fn foo() where Self: Other, { } - | --- ...because associated function `foo` has no `self` parameter + | ^^^ ...because associated function `foo` has no `self` parameter LL | fn bar(self: ()) {} - | -- ...because method `bar`'s `self` parameter cannot be dispatched on -... -LL | fn bar(x: &dyn Trait) {} - | ^^^^^^^^^^ the trait `Trait` cannot be made into an object + | ^^ ...because method `bar`'s `self` parameter cannot be dispatched on +help: consider turning `foo` into a method by giving it a `&self` argument | -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn foo(&self) where Self: Other, { } + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() where Self: Other, Self: Sized, { } | ^^^^^^^^^^^^^ diff --git a/src/test/ui/traits/issue-72410.stderr b/src/test/ui/traits/issue-72410.stderr index 1db2320841f..c70fbb3565e 100644 --- a/src/test/ui/traits/issue-72410.stderr +++ b/src/test/ui/traits/issue-72410.stderr @@ -1,14 +1,21 @@ error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/issue-72410.rs:14:19 | +LL | where for<'a> &'a mut [dyn Bar]: ; + | ^^^^^^^^^^^^^^^^^ the trait `Bar` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/issue-72410.rs:13:8 + | LL | pub trait Bar { | --- this trait cannot be made into an object... LL | fn map() - | --- ...because associated function `map` has no `self` parameter -LL | where for<'a> &'a mut [dyn Bar]: ; - | ^^^^^^^^^^^^^^^^^ the trait `Bar` cannot be made into an object + | ^^^ ...because associated function `map` has no `self` parameter +help: consider turning `map` into a method by giving it a `&self` argument | -help: consider turning `map` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn map(&self) + | ^^^^^ +help: alternatively, consider constraining `map` so it does not apply to trait objects | LL | where for<'a> &'a mut [dyn Bar]:, Self: Sized ; | ^^^^^^^^^^^^^ diff --git a/src/test/ui/traits/trait-alias/trait-alias-object-fail.stderr b/src/test/ui/traits/trait-alias/trait-alias-object-fail.stderr index 1f54e03ee6e..a6e54d42aa7 100644 --- a/src/test/ui/traits/trait-alias/trait-alias-object-fail.stderr +++ b/src/test/ui/traits/trait-alias/trait-alias-object-fail.stderr @@ -3,11 +3,12 @@ error[E0038]: the trait `Eq` cannot be made into an object | LL | let _: &dyn EqAlias = &123; | ^^^^^^^^^^^ the trait `Eq` cannot be made into an object - | - ::: $SRC_DIR/core/src/cmp.rs:LL:COL + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $SRC_DIR/core/src/cmp.rs:LL:COL | LL | pub trait Eq: PartialEq<Self> { - | --------------- the trait cannot be made into an object because it uses `Self` as a type parameter in this + | ^^^^^^^^^^^^^^^ the trait cannot be made into an object because it uses `Self` as a type parameter in this error[E0191]: the value of the associated type `Item` (from trait `Iterator`) must be specified --> $DIR/trait-alias-object-fail.rs:9:17 diff --git a/src/test/ui/traits/trait-item-privacy.stderr b/src/test/ui/traits/trait-item-privacy.stderr index 3be4f110973..c7143e5e253 100644 --- a/src/test/ui/traits/trait-item-privacy.stderr +++ b/src/test/ui/traits/trait-item-privacy.stderr @@ -112,23 +112,25 @@ LL | C::A; error[E0038]: the trait `assoc_const::C` cannot be made into an object --> $DIR/trait-item-privacy.rs:101:5 | +LL | C::A; + | ^^^^ the trait `assoc_const::C` cannot be made into an object + | + = help: consider moving `C` to another trait + = help: consider moving `B` to another trait + = help: consider moving `A` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/trait-item-privacy.rs:25:15 + | LL | const A: u8 = 0; - | - ...because it contains this associated `const` + | ^ ...because it contains this associated `const` ... LL | const B: u8 = 0; - | - ...because it contains this associated `const` + | ^ ...because it contains this associated `const` ... LL | pub trait C: A + B { | - this trait cannot be made into an object... LL | const C: u8 = 0; - | - ...because it contains this associated `const` -... -LL | C::A; - | ^^^^ the trait `assoc_const::C` cannot be made into an object - | - = help: consider moving `C` to another trait - = help: consider moving `B` to another trait - = help: consider moving `A` to another trait + | ^ ...because it contains this associated `const` error[E0223]: ambiguous associated type --> $DIR/trait-item-privacy.rs:115:12 diff --git a/src/test/ui/traits/trait-object-macro-matcher.stderr b/src/test/ui/traits/trait-object-macro-matcher.stderr index bc567360734..af2989ae188 100644 --- a/src/test/ui/traits/trait-object-macro-matcher.stderr +++ b/src/test/ui/traits/trait-object-macro-matcher.stderr @@ -11,6 +11,7 @@ LL | m!(dyn Copy + Send + 'static); | ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` cannot be made into an object | = note: the trait cannot be made into an object because it requires `Self: Sized` + = note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> error: aborting due to 2 previous errors diff --git a/src/test/ui/traits/trait-object-safety.stderr b/src/test/ui/traits/trait-object-safety.stderr index 3fa7c0c484e..5f034e2a9ef 100644 --- a/src/test/ui/traits/trait-object-safety.stderr +++ b/src/test/ui/traits/trait-object-safety.stderr @@ -1,17 +1,23 @@ error[E0038]: the trait `Tr` cannot be made into an object --> $DIR/trait-object-safety.rs:15:22 | -LL | trait Tr { - | -- this trait cannot be made into an object... -LL | fn foo(); - | --- ...because associated function `foo` has no `self` parameter -... LL | let _: &dyn Tr = &St; | ^^^ the trait `Tr` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/trait-object-safety.rs:4:8 + | +LL | trait Tr { + | -- this trait cannot be made into an object... +LL | fn foo(); + | ^^^ ...because associated function `foo` has no `self` parameter = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Tr>` for `&St` = note: required by cast to type `&dyn Tr` -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +help: consider turning `foo` into a method by giving it a `&self` argument + | +LL | fn foo(&self); + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() where Self: Sized; | ^^^^^^^^^^^^^^^^^ @@ -19,15 +25,21 @@ LL | fn foo() where Self: Sized; error[E0038]: the trait `Tr` cannot be made into an object --> $DIR/trait-object-safety.rs:15:12 | +LL | let _: &dyn Tr = &St; + | ^^^^^^^ the trait `Tr` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/trait-object-safety.rs:4:8 + | LL | trait Tr { | -- this trait cannot be made into an object... LL | fn foo(); - | --- ...because associated function `foo` has no `self` parameter -... -LL | let _: &dyn Tr = &St; - | ^^^^^^^ the trait `Tr` cannot be made into an object + | ^^^ ...because associated function `foo` has no `self` parameter +help: consider turning `foo` into a method by giving it a `&self` argument | -help: consider turning `foo` into a method by giving it a `&self` argument or constraining it so it does not apply to trait objects +LL | fn foo(&self); + | ^^^^^ +help: alternatively, consider constraining `foo` so it does not apply to trait objects | LL | fn foo() where Self: Sized; | ^^^^^^^^^^^^^^^^^ diff --git a/src/test/ui/traits/trait-test-2.stderr b/src/test/ui/traits/trait-test-2.stderr index 0a62f1aeb27..0fab29f89c4 100644 --- a/src/test/ui/traits/trait-test-2.stderr +++ b/src/test/ui/traits/trait-test-2.stderr @@ -13,32 +13,36 @@ LL | 10.blah::<i32, i32>(); error[E0038]: the trait `bar` cannot be made into an object --> $DIR/trait-test-2.rs:11:16 | -LL | trait bar { fn dup(&self) -> Self; fn blah<X>(&self); } - | --- ---- ---- ...because method `blah` has generic type parameters - | | | - | | ...because method `dup` references the `Self` type in its return type - | this trait cannot be made into an object... -... LL | (box 10 as Box<dyn bar>).dup(); | ^^^^^^^^^^^^ the trait `bar` cannot be made into an object | = help: consider moving `dup` to another trait = help: consider moving `blah` to another trait - -error[E0038]: the trait `bar` cannot be made into an object - --> $DIR/trait-test-2.rs:11:6 +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/trait-test-2.rs:4:30 | LL | trait bar { fn dup(&self) -> Self; fn blah<X>(&self); } - | --- ---- ---- ...because method `blah` has generic type parameters + | --- ^^^^ ^^^^ ...because method `blah` has generic type parameters | | | | | ...because method `dup` references the `Self` type in its return type | this trait cannot be made into an object... -... + +error[E0038]: the trait `bar` cannot be made into an object + --> $DIR/trait-test-2.rs:11:6 + | LL | (box 10 as Box<dyn bar>).dup(); | ^^^^^^ the trait `bar` cannot be made into an object | = help: consider moving `dup` to another trait = help: consider moving `blah` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/trait-test-2.rs:4:30 + | +LL | trait bar { fn dup(&self) -> Self; fn blah<X>(&self); } + | --- ^^^^ ^^^^ ...because method `blah` has generic type parameters + | | | + | | ...because method `dup` references the `Self` type in its return type + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn bar>>` for `Box<{integer}>` = note: required by cast to type `Box<dyn bar>` diff --git a/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr b/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr index 539189982a8..c9a5297c42f 100644 --- a/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr +++ b/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr @@ -13,15 +13,17 @@ LL | let y = x as dyn MyAdd<i32>; error[E0038]: the trait `MyAdd` cannot be made into an object --> $DIR/type-parameter-defaults-referencing-Self-ppaux.rs:14:18 | -LL | trait MyAdd<Rhs=Self> { fn add(&self, other: &Rhs) -> Self; } - | ----- ---- ...because method `add` references the `Self` type in its return type - | | - | this trait cannot be made into an object... -... LL | let y = x as dyn MyAdd<i32>; | ^^^^^^^^^^^^^^ the trait `MyAdd` cannot be made into an object | = help: consider moving `add` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/type-parameter-defaults-referencing-Self-ppaux.rs:6:55 + | +LL | trait MyAdd<Rhs=Self> { fn add(&self, other: &Rhs) -> Self; } + | ----- ^^^^ ...because method `add` references the `Self` type in its return type + | | + | this trait cannot be made into an object... error: aborting due to 2 previous errors diff --git a/src/test/ui/wf/wf-convert-unsafe-trait-obj-box.stderr b/src/test/ui/wf/wf-convert-unsafe-trait-obj-box.stderr index e707839a97e..6eadcbac6bd 100644 --- a/src/test/ui/wf/wf-convert-unsafe-trait-obj-box.stderr +++ b/src/test/ui/wf/wf-convert-unsafe-trait-obj-box.stderr @@ -1,42 +1,48 @@ error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj-box.rs:16:33 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | let t_box: Box<dyn Trait> = Box::new(S); | ^^^^^^^^^^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-convert-unsafe-trait-obj-box.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn Trait>>` for `Box<S>` = note: required by cast to type `Box<dyn Trait>` error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj-box.rs:17:15 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | takes_box(Box::new(S)); | ^^^^^^^^^^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-convert-unsafe-trait-obj-box.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn Trait>>` for `Box<S>` = note: required by cast to type `Box<(dyn Trait + 'static)>` error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj-box.rs:15:5 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | Box::new(S) as Box<dyn Trait>; | ^^^^^^^^^^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-convert-unsafe-trait-obj-box.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn Trait>>` for `Box<S>` = note: required by cast to type `Box<dyn Trait>` diff --git a/src/test/ui/wf/wf-convert-unsafe-trait-obj.stderr b/src/test/ui/wf/wf-convert-unsafe-trait-obj.stderr index 08d4808b77d..bb4899ee162 100644 --- a/src/test/ui/wf/wf-convert-unsafe-trait-obj.stderr +++ b/src/test/ui/wf/wf-convert-unsafe-trait-obj.stderr @@ -1,42 +1,48 @@ error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj.rs:16:25 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | let t: &dyn Trait = &S; | ^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-convert-unsafe-trait-obj.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Trait>` for `&S` = note: required by cast to type `&dyn Trait` error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj.rs:17:17 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | takes_trait(&S); | ^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-convert-unsafe-trait-obj.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Trait>` for `&S` = note: required by cast to type `&dyn Trait` error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj.rs:15:5 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | &S as &dyn Trait; | ^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-convert-unsafe-trait-obj.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Trait>` for `&S` = note: required by cast to type `&dyn Trait` diff --git a/src/test/ui/wf/wf-fn-where-clause.stderr b/src/test/ui/wf/wf-fn-where-clause.stderr index e7921f3496c..bd10d453576 100644 --- a/src/test/ui/wf/wf-fn-where-clause.stderr +++ b/src/test/ui/wf/wf-fn-where-clause.stderr @@ -37,6 +37,7 @@ LL | fn bar() where Vec<dyn Copy>:, {} | ^^^^^^^^^^^^^ the trait `Copy` cannot be made into an object | = note: the trait cannot be made into an object because it requires `Self: Sized` + = note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> error: aborting due to 3 previous errors diff --git a/src/test/ui/wf/wf-object-safe.stderr b/src/test/ui/wf/wf-object-safe.stderr index 8935d766354..b5e30afe880 100644 --- a/src/test/ui/wf/wf-object-safe.stderr +++ b/src/test/ui/wf/wf-object-safe.stderr @@ -1,15 +1,17 @@ error[E0038]: the trait `A` cannot be made into an object --> $DIR/wf-object-safe.rs:9:13 | -LL | trait A { - | - this trait cannot be made into an object... -LL | fn foo(&self, _x: &Self); - | ----- ...because method `foo` references the `Self` type in this parameter -... LL | let _x: &dyn A; | ^^^^^^ the trait `A` cannot be made into an object | = help: consider moving `foo` to another trait +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-object-safe.rs:5:23 + | +LL | trait A { + | - this trait cannot be made into an object... +LL | fn foo(&self, _x: &Self); + | ^^^^^ ...because method `foo` references the `Self` type in this parameter error: aborting due to previous error diff --git a/src/test/ui/wf/wf-unsafe-trait-obj-match.stderr b/src/test/ui/wf/wf-unsafe-trait-obj-match.stderr index d0f43f800fd..58ca092433b 100644 --- a/src/test/ui/wf/wf-unsafe-trait-obj-match.stderr +++ b/src/test/ui/wf/wf-unsafe-trait-obj-match.stderr @@ -15,28 +15,32 @@ LL | | } error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-unsafe-trait-obj-match.rs:26:21 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | Some(()) => &S, | ^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-unsafe-trait-obj-match.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Trait>` for `&S` = note: required by cast to type `&dyn Trait` error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-unsafe-trait-obj-match.rs:25:25 | -LL | trait Trait: Sized {} - | ----- ----- ...because it requires `Self: Sized` - | | - | this trait cannot be made into an object... -... LL | let t: &dyn Trait = match opt() { | ^^^^^^^^^^^ the trait `Trait` cannot be made into an object | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $DIR/wf-unsafe-trait-obj-match.rs:6:14 + | +LL | trait Trait: Sized {} + | ----- ^^^^^ ...because it requires `Self: Sized` + | | + | this trait cannot be made into an object... = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Trait>` for `&R` = note: required by cast to type `&dyn Trait` |