From f5bae722be1f81f70d92e30cec1930f7cefc6313 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Esteban=20K=C3=BCber?= Date: Mon, 12 Aug 2024 22:57:14 +0000 Subject: [PATCH] Point at explicit `'static` obligations on a trait Given `trait Any: 'static` and a `struct` with a `Box` field, point at the `'static` bound in `Any` to explain why `'a: 'static`. ``` error[E0478]: lifetime bound not satisfied --> f202.rs:2:12 | 2 | value: Box, | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | note: lifetime parameter instantiated with the lifetime `'a` as defined here --> f202.rs:1:14 | 1 | struct Hello<'a> { | ^^ note: but lifetime parameter must outlive the static lifetime --> /home/gh-estebank/rust/library/core/src/any.rs:113:16 | 113 | pub trait Any: 'static { | ^^^^^^^ ``` Partially address #33652. --- .../rustc_hir_analysis/src/check/wfcheck.rs | 2 +- compiler/rustc_infer/src/infer/context.rs | 2 +- compiler/rustc_infer/src/infer/mod.rs | 10 ++++-- .../nice_region_error/placeholder_relation.rs | 2 +- .../src/error_reporting/infer/note.rs | 4 +-- .../src/error_reporting/infer/region.rs | 26 +++++++++++++-- .../regions/explicit-static-bound-on-trait.rs | 13 ++++++++ .../explicit-static-bound-on-trait.stderr | 32 +++++++++++++++++++ 8 files changed, 80 insertions(+), 11 deletions(-) create mode 100644 tests/ui/regions/explicit-static-bound-on-trait.rs create mode 100644 tests/ui/regions/explicit-static-bound-on-trait.stderr diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs index bdf2914fc50c6..6e6e0e90219e5 100644 --- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs +++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs @@ -747,7 +747,7 @@ fn region_known_to_outlive<'tcx>( region_b: ty::Region<'tcx>, ) -> bool { test_region_obligations(tcx, id, param_env, wf_tys, |infcx| { - infcx.sub_regions(infer::RelateRegionParamBound(DUMMY_SP), region_b, region_a); + infcx.sub_regions(infer::RelateRegionParamBound(DUMMY_SP, None), region_b, region_a); }) } diff --git a/compiler/rustc_infer/src/infer/context.rs b/compiler/rustc_infer/src/infer/context.rs index f35a8162d96f1..95888beb6b198 100644 --- a/compiler/rustc_infer/src/infer/context.rs +++ b/compiler/rustc_infer/src/infer/context.rs @@ -167,7 +167,7 @@ impl<'tcx> InferCtxtLike for InferCtxt<'tcx> { } fn sub_regions(&self, sub: ty::Region<'tcx>, sup: ty::Region<'tcx>) { - self.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP), sub, sup) + self.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP, None), sub, sup) } fn register_ty_outlives(&self, ty: Ty<'tcx>, r: ty::Region<'tcx>) { diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index f2fc25a2d2e10..5aa7f25968534 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -390,7 +390,7 @@ pub enum SubregionOrigin<'tcx> { /// The given region parameter was instantiated with a region /// that must outlive some other region. - RelateRegionParamBound(Span), + RelateRegionParamBound(Span, Option>), /// Creating a pointer `b` to contents of another reference. Reborrow(Span), @@ -859,7 +859,7 @@ impl<'tcx> InferCtxt<'tcx> { ) { self.enter_forall(predicate, |ty::OutlivesPredicate(r_a, r_b)| { let origin = SubregionOrigin::from_obligation_cause(cause, || { - RelateRegionParamBound(cause.span) + RelateRegionParamBound(cause.span, None) }); self.sub_regions(origin, r_b, r_a); // `b : a` ==> `a <= b` }) @@ -1685,7 +1685,7 @@ impl<'tcx> SubregionOrigin<'tcx> { Subtype(ref a) => a.span(), RelateObjectBound(a) => a, RelateParamBound(a, ..) => a, - RelateRegionParamBound(a) => a, + RelateRegionParamBound(a, _) => a, Reborrow(a) => a, ReferenceOutlivesReferent(_, a) => a, CompareImplItemObligation { span, .. } => span, @@ -1726,6 +1726,10 @@ impl<'tcx> SubregionOrigin<'tcx> { SubregionOrigin::AscribeUserTypeProvePredicate(span) } + traits::ObligationCauseCode::ObjectTypeBound(ty, _reg) => { + SubregionOrigin::RelateRegionParamBound(cause.span, Some(ty)) + } + _ => default(), } } diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/placeholder_relation.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/placeholder_relation.rs index 9c772f42ccaa3..f2a7da707b81a 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/placeholder_relation.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/placeholder_relation.rs @@ -11,7 +11,7 @@ impl<'tcx> NiceRegionError<'_, 'tcx> { pub(super) fn try_report_placeholder_relation(&self) -> Option> { match &self.error { Some(RegionResolutionError::ConcreteFailure( - SubregionOrigin::RelateRegionParamBound(span), + SubregionOrigin::RelateRegionParamBound(span, _), Region(Interned( RePlaceholder(ty::Placeholder { bound: ty::BoundRegion { kind: sub_name, .. }, diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/note.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/note.rs index 04e1be22a4d06..600da730845e8 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/infer/note.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/infer/note.rs @@ -52,7 +52,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { .add_to_diag(err); } } - infer::RelateRegionParamBound(span) => { + infer::RelateRegionParamBound(span, _) => { RegionOriginNote::Plain { span, msg: fluent::infer_relate_region_param_bound } .add_to_diag(err); } @@ -199,7 +199,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { note, }) } - infer::RelateRegionParamBound(span) => { + infer::RelateRegionParamBound(span, _) => { let param_instantiated = note_and_explain::RegionExplanation::new( self.tcx, generic_param_scope, diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs index 877a8a23d7f2b..765237557d9b3 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/infer/region.rs @@ -257,7 +257,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { .add_to_diag(err); } } - infer::RelateRegionParamBound(span) => { + infer::RelateRegionParamBound(span, _) => { RegionOriginNote::Plain { span, msg: fluent::trait_selection_relate_region_param_bound, @@ -410,7 +410,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { note, }) } - infer::RelateRegionParamBound(span) => { + infer::RelateRegionParamBound(span, ty) => { let param_instantiated = note_and_explain::RegionExplanation::new( self.tcx, generic_param_scope, @@ -419,11 +419,31 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { note_and_explain::PrefixKind::LfParamInstantiatedWith, note_and_explain::SuffixKind::Empty, ); + let mut alt_span = None; + if let Some(ty) = ty + && sub.is_static() + && let ty::Dynamic(preds, _, ty::DynKind::Dyn) = ty.kind() + && let Some(def_id) = preds.principal_def_id() + { + for (clause, span) in + self.tcx.predicates_of(def_id).instantiate_identity(self.tcx) + { + if let ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(a, b)) = + clause.kind().skip_binder() + && let ty::Param(param) = a.kind() + && param.name == kw::SelfUpper + && b.is_static() + { + // Point at explicit `'static` bound on the trait (`trait T: 'static`). + alt_span = Some(span); + } + } + } let param_must_outlive = note_and_explain::RegionExplanation::new( self.tcx, generic_param_scope, sub, - None, + alt_span, note_and_explain::PrefixKind::LfParamMustOutlive, note_and_explain::SuffixKind::Empty, ); diff --git a/tests/ui/regions/explicit-static-bound-on-trait.rs b/tests/ui/regions/explicit-static-bound-on-trait.rs new file mode 100644 index 0000000000000..835da34d1bbf9 --- /dev/null +++ b/tests/ui/regions/explicit-static-bound-on-trait.rs @@ -0,0 +1,13 @@ +struct Hello<'a> { + value: Box, + //~^ ERROR lifetime bound not satisfied +} + +impl<'a> Hello<'a> { + fn new(value: T) -> Self { + Self { value: Box::new(value) } + //~^ ERROR the parameter type `T` may not live long enough + } +} + +fn main() {} diff --git a/tests/ui/regions/explicit-static-bound-on-trait.stderr b/tests/ui/regions/explicit-static-bound-on-trait.stderr new file mode 100644 index 0000000000000..30d39c6e86e95 --- /dev/null +++ b/tests/ui/regions/explicit-static-bound-on-trait.stderr @@ -0,0 +1,32 @@ +error[E0478]: lifetime bound not satisfied + --> $DIR/explicit-static-bound-on-trait.rs:2:12 + | +LL | value: Box, + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: lifetime parameter instantiated with the lifetime `'a` as defined here + --> $DIR/explicit-static-bound-on-trait.rs:1:14 + | +LL | struct Hello<'a> { + | ^^ +note: but lifetime parameter must outlive the static lifetime + --> $SRC_DIR/core/src/any.rs:LL:COL + +error[E0310]: the parameter type `T` may not live long enough + --> $DIR/explicit-static-bound-on-trait.rs:8:23 + | +LL | Self { value: Box::new(value) } + | ^^^^^^^^^^^^^^^ + | | + | the parameter type `T` must be valid for the static lifetime... + | ...so that the type `T` will meet its required lifetime bounds + | +help: consider adding an explicit lifetime bound + | +LL | fn new(value: T) -> Self { + | +++++++++ + +error: aborting due to 2 previous errors + +Some errors have detailed explanations: E0310, E0478. +For more information about an error, try `rustc --explain E0310`.