From 3d19c8defd776eb7e9e113cf49c3e1d2f51e408e Mon Sep 17 00:00:00 2001 From: Jack Huey <31162821+jackh726@users.noreply.github.com> Date: Sat, 8 Jan 2022 23:30:19 -0500 Subject: [PATCH] Suggest copying trait associated type bounds on lifetime error --- .../error_reporting/nice_region_error/mod.rs | 2 +- .../src/infer/error_reporting/note.rs | 52 +++++++++++++++++++ compiler/rustc_infer/src/infer/mod.rs | 17 ++++++ compiler/rustc_middle/src/traits/mod.rs | 6 +++ .../src/traits/error_reporting/suggestions.rs | 3 +- .../rustc_typeck/src/check/compare_method.rs | 9 +++- .../impl_bounds.stderr | 7 ++- .../generic-associated-types/issue-88595.rs | 5 +- .../issue-88595.stderr | 22 +------- .../issue-90014.stderr | 7 ++- .../generic-associated-types/issue-92033.rs | 39 ++++++++++++++ .../issue-92033.stderr | 22 ++++++++ 12 files changed, 163 insertions(+), 28 deletions(-) create mode 100644 src/test/ui/generic-associated-types/issue-92033.rs create mode 100644 src/test/ui/generic-associated-types/issue-92033.stderr diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs index 8512597cb9137..f44e6e04346b2 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs @@ -64,7 +64,7 @@ impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> { .or_else(|| self.try_report_mismatched_static_lifetime()) } - pub fn regions(&self) -> Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)> { + pub(super) fn regions(&self) -> Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)> { match (&self.error, self.regions) { (Some(ConcreteFailure(origin, sub, sup)), None) => Some((origin.span(), *sub, *sup)), (Some(SubSupConflict(_, _, origin, sub, _, sup, _)), None) => { diff --git a/compiler/rustc_infer/src/infer/error_reporting/note.rs b/compiler/rustc_infer/src/infer/error_reporting/note.rs index 8e5efa12ac6c1..8671ecba6e924 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/note.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/note.rs @@ -102,6 +102,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { "...so that the definition in impl matches the definition from the trait", ); } + infer::CheckAssociatedTypeBounds { ref parent, .. } => { + self.note_region_origin(err, &parent); + } } } @@ -345,6 +348,55 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { trait_item_def_id, &format!("`{}: {}`", sup, sub), ), + infer::CheckAssociatedTypeBounds { impl_item_def_id, trait_item_def_id, parent } => { + let mut err = self.report_concrete_failure(*parent, sub, sup); + + let trait_item_span = self.tcx.def_span(trait_item_def_id); + let item_name = self.tcx.item_name(impl_item_def_id); + err.span_label( + trait_item_span, + format!("definition of `{}` from trait", item_name), + ); + + let trait_predicates = self.tcx.explicit_predicates_of(trait_item_def_id); + let impl_predicates = self.tcx.explicit_predicates_of(impl_item_def_id); + + let impl_predicates: rustc_data_structures::stable_set::FxHashSet<_> = + impl_predicates.predicates.into_iter().map(|(pred, _)| pred).collect(); + let clauses: Vec<_> = trait_predicates + .predicates + .into_iter() + .filter(|&(pred, _)| !impl_predicates.contains(pred)) + .map(|(pred, _)| format!("{}", pred)) + .collect(); + + if !clauses.is_empty() { + let where_clause_span = self + .tcx + .hir() + .get_generics(impl_item_def_id.expect_local()) + .unwrap() + .where_clause + .tail_span_for_suggestion(); + + let suggestion = format!( + "{} {}", + if !impl_predicates.is_empty() { "," } else { " where" }, + clauses.join(", "), + ); + err.span_suggestion( + where_clause_span, + &format!( + "try copying {} from the trait", + if clauses.len() > 1 { "these clauses" } else { "this clause" } + ), + suggestion, + rustc_errors::Applicability::MaybeIncorrect, + ); + } + + err + } } } diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index f0a4ec813134c..57ac98ca897ee 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -438,6 +438,13 @@ pub enum SubregionOrigin<'tcx> { /// Comparing the signature and requirements of an impl associated type /// against the containing trait CompareImplTypeObligation { span: Span, impl_item_def_id: DefId, trait_item_def_id: DefId }, + + /// Checking that the bounds of a trait's associated type hold for a given impl + CheckAssociatedTypeBounds { + parent: Box>, + impl_item_def_id: DefId, + trait_item_def_id: DefId, + }, } // `SubregionOrigin` is used a lot. Make sure it doesn't unintentionally get bigger. @@ -1832,6 +1839,7 @@ impl<'tcx> SubregionOrigin<'tcx> { ReferenceOutlivesReferent(_, a) => a, CompareImplMethodObligation { span, .. } => span, CompareImplTypeObligation { span, .. } => span, + CheckAssociatedTypeBounds { ref parent, .. } => parent.span(), } } @@ -1862,6 +1870,15 @@ impl<'tcx> SubregionOrigin<'tcx> { trait_item_def_id, }, + traits::ObligationCauseCode::CheckAssociatedTypeBounds { + impl_item_def_id, + trait_item_def_id, + } => SubregionOrigin::CheckAssociatedTypeBounds { + impl_item_def_id, + trait_item_def_id, + parent: Box::new(default()), + }, + _ => default(), } } diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs index 1123cab807651..b54418e520171 100644 --- a/compiler/rustc_middle/src/traits/mod.rs +++ b/compiler/rustc_middle/src/traits/mod.rs @@ -285,6 +285,12 @@ pub enum ObligationCauseCode<'tcx> { trait_item_def_id: DefId, }, + /// Checking that the bounds of a trait's associated type hold for a given impl + CheckAssociatedTypeBounds { + impl_item_def_id: DefId, + trait_item_def_id: DefId, + }, + /// Checking that this expression can be assigned where it needs to be // FIXME(eddyb) #11161 is the original Expr required? ExprAssignable, diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index 40cb9647a3555..6068b90aef82c 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -1932,7 +1932,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { | ObligationCauseCode::AwaitableExpr(_) | ObligationCauseCode::ForLoopIterator | ObligationCauseCode::QuestionMark - | ObligationCauseCode::LetElse => {} + | ObligationCauseCode::LetElse + | ObligationCauseCode::CheckAssociatedTypeBounds { .. } => {} ObligationCauseCode::SliceOrArrayElem => { err.note("slice and array elements must have `Sized` type"); } diff --git a/compiler/rustc_typeck/src/check/compare_method.rs b/compiler/rustc_typeck/src/check/compare_method.rs index 457e9cf1ea54a..38449c2a76a5b 100644 --- a/compiler/rustc_typeck/src/check/compare_method.rs +++ b/compiler/rustc_typeck/src/check/compare_method.rs @@ -1378,7 +1378,14 @@ pub fn check_type_bounds<'tcx>( let mut selcx = traits::SelectionContext::new(&infcx); let impl_ty_hir_id = tcx.hir().local_def_id_to_hir_id(impl_ty.def_id.expect_local()); - let normalize_cause = traits::ObligationCause::misc(impl_ty_span, impl_ty_hir_id); + let normalize_cause = ObligationCause::new( + impl_ty_span, + impl_ty_hir_id, + ObligationCauseCode::CheckAssociatedTypeBounds { + impl_item_def_id: impl_ty.def_id, + trait_item_def_id: trait_ty.def_id, + }, + ); let mk_cause = |span: Span| { let code = if span.is_dummy() { traits::MiscObligation diff --git a/src/test/ui/generic-associated-types/impl_bounds.stderr b/src/test/ui/generic-associated-types/impl_bounds.stderr index 5be431f2933b3..bd0dea372194d 100644 --- a/src/test/ui/generic-associated-types/impl_bounds.stderr +++ b/src/test/ui/generic-associated-types/impl_bounds.stderr @@ -19,8 +19,13 @@ LL | type B<'a, 'b> where 'b: 'a = (&'a(), &'b ()); error[E0478]: lifetime bound not satisfied --> $DIR/impl_bounds.rs:17:35 | +LL | type B<'a, 'b> where 'a: 'b; + | ---------------------------- definition of `B` from trait +... LL | type B<'a, 'b> where 'b: 'a = (&'a(), &'b ()); - | ^^^^^^^^^^^^^^^ + | - ^^^^^^^^^^^^^^^ + | | + | help: try copying this clause from the trait: `, 'a: 'b` | note: lifetime parameter instantiated with the lifetime `'a` as defined here --> $DIR/impl_bounds.rs:17:12 diff --git a/src/test/ui/generic-associated-types/issue-88595.rs b/src/test/ui/generic-associated-types/issue-88595.rs index e397390783f66..c97d17811ba7c 100644 --- a/src/test/ui/generic-associated-types/issue-88595.rs +++ b/src/test/ui/generic-associated-types/issue-88595.rs @@ -8,7 +8,7 @@ trait A<'a> { // FIXME(generic_associated_types): Remove one of the below bounds // https://github.com/rust-lang/rust/pull/90678#discussion_r744976085 where - 'a: 'b, Self: 'a, Self: 'b; + Self: 'a, Self: 'b; fn a(&'a self) -> Self::B<'a>; } @@ -17,8 +17,7 @@ struct C; impl<'a> A<'a> for C { type B<'b> = impl Clone; - //~^ ERROR: lifetime bound not satisfied - //~| ERROR: could not find defining uses + //~^ ERROR: could not find defining uses fn a(&'a self) -> Self::B<'a> {} //~ ERROR: non-defining opaque type use in defining scope } diff --git a/src/test/ui/generic-associated-types/issue-88595.stderr b/src/test/ui/generic-associated-types/issue-88595.stderr index cb462871ccd32..4e4f86bbac87c 100644 --- a/src/test/ui/generic-associated-types/issue-88595.stderr +++ b/src/test/ui/generic-associated-types/issue-88595.stderr @@ -1,22 +1,5 @@ -error[E0478]: lifetime bound not satisfied - --> $DIR/issue-88595.rs:19:18 - | -LL | type B<'b> = impl Clone; - | ^^^^^^^^^^ - | -note: lifetime parameter instantiated with the lifetime `'a` as defined here - --> $DIR/issue-88595.rs:18:6 - | -LL | impl<'a> A<'a> for C { - | ^^ -note: but lifetime parameter must outlive the lifetime `'b` as defined here - --> $DIR/issue-88595.rs:19:12 - | -LL | type B<'b> = impl Clone; - | ^^ - error: non-defining opaque type use in defining scope - --> $DIR/issue-88595.rs:23:23 + --> $DIR/issue-88595.rs:22:23 | LL | fn a(&'a self) -> Self::B<'a> {} | ^^^^^^^^^^^ @@ -35,6 +18,5 @@ error: could not find defining uses LL | type B<'b> = impl Clone; | ^^^^^^^^^^ -error: aborting due to 3 previous errors +error: aborting due to 2 previous errors -For more information about this error, try `rustc --explain E0478`. diff --git a/src/test/ui/generic-associated-types/issue-90014.stderr b/src/test/ui/generic-associated-types/issue-90014.stderr index 23e8d08af3428..f8fb71bbddb4b 100644 --- a/src/test/ui/generic-associated-types/issue-90014.stderr +++ b/src/test/ui/generic-associated-types/issue-90014.stderr @@ -1,8 +1,13 @@ error[E0477]: the type `&mut ()` does not fulfill the required lifetime --> $DIR/issue-90014.rs:14:20 | +LL | type Fut<'a> where Self: 'a; + | ---------------------------- definition of `Fut` from trait +... LL | type Fut<'a> = impl Future; - | ^^^^^^^^^^^^^^^^^^^^^^^^ + | - ^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | help: try copying this clause from the trait: `where Self: 'a` | note: type must outlive the lifetime `'a` as defined here --> $DIR/issue-90014.rs:14:14 diff --git a/src/test/ui/generic-associated-types/issue-92033.rs b/src/test/ui/generic-associated-types/issue-92033.rs new file mode 100644 index 0000000000000..1d5f7d5c0099e --- /dev/null +++ b/src/test/ui/generic-associated-types/issue-92033.rs @@ -0,0 +1,39 @@ +#![feature(generic_associated_types)] + +struct Texture; + +trait Surface { + type TextureIter<'a>: Iterator + where + Self: 'a; + + fn get_texture(&self) -> Self::TextureIter<'_>; +} + +trait Swapchain { + type Surface<'a>: Surface + where + Self: 'a; + + fn get_surface(&self) -> Self::Surface<'_>; +} + +impl<'s> Surface for &'s Texture { + type TextureIter<'a> = std::option::IntoIter<&'a Texture>; + //~^ ERROR the type + + fn get_texture(&self) -> Self::TextureIter<'_> { + let option: Option<&Texture> = Some(self); + option.into_iter() + } +} + +impl Swapchain for Texture { + type Surface<'a> = &'a Texture; + + fn get_surface(&self) -> Self::Surface<'_> { + self + } +} + +fn main() {} diff --git a/src/test/ui/generic-associated-types/issue-92033.stderr b/src/test/ui/generic-associated-types/issue-92033.stderr new file mode 100644 index 0000000000000..caa6618f39884 --- /dev/null +++ b/src/test/ui/generic-associated-types/issue-92033.stderr @@ -0,0 +1,22 @@ +error[E0477]: the type `&'s Texture` does not fulfill the required lifetime + --> $DIR/issue-92033.rs:22:28 + | +LL | / type TextureIter<'a>: Iterator +LL | | where +LL | | Self: 'a; + | |_________________- definition of `TextureIter` from trait +... +LL | type TextureIter<'a> = std::option::IntoIter<&'a Texture>; + | - ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | help: try copying this clause from the trait: `where Self: 'a` + | +note: type must outlive the lifetime `'a` as defined here + --> $DIR/issue-92033.rs:22:22 + | +LL | type TextureIter<'a> = std::option::IntoIter<&'a Texture>; + | ^^ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0477`.