diff options
5 files changed, 103 insertions, 11 deletions
diff --git a/compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl b/compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl index 0894bbcaad4..a5cb8a88819 100644 --- a/compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl +++ b/compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl @@ -17,6 +17,8 @@ hir_analysis_lifetimes_or_bounds_mismatch_on_trait = lifetime parameters or bounds on {$item_kind} `{$ident}` do not match the trait declaration .label = lifetimes do not match {$item_kind} in trait .generics_label = lifetimes in impl do not match this {$item_kind} in trait + .where_label = this `where` clause might not match the one in the trait + .bounds_label = this bound might be missing in the impl hir_analysis_drop_impl_on_wrong_item = the `Drop` trait may only be implemented for local structs, enums, and unions diff --git a/compiler/rustc_hir_analysis/src/check/compare_method.rs b/compiler/rustc_hir_analysis/src/check/compare_method.rs index 82a77416a19..1d6f9b29176 100644 --- a/compiler/rustc_hir_analysis/src/check/compare_method.rs +++ b/compiler/rustc_hir_analysis/src/check/compare_method.rs @@ -751,17 +751,45 @@ fn check_region_bounds_on_impl_item<'tcx>( .get_generics(impl_m.def_id.expect_local()) .expect("expected impl item to have generics or else we can't compare them") .span; - let generics_span = if let Some(local_def_id) = trait_m.def_id.as_local() { - Some( - tcx.hir() - .get_generics(local_def_id) - .expect("expected trait item to have generics or else we can't compare them") - .span, - ) - } else { - None - }; + let mut generics_span = None; + let mut bounds_span = vec![]; + let mut where_span = None; + if let Some(trait_node) = tcx.hir().get_if_local(trait_m.def_id) + && let Some(trait_generics) = trait_node.generics() + { + generics_span = Some(trait_generics.span); + // FIXME: we could potentially look at the impl's bounds to not point at bounds that + // *are* present in the impl. + for p in trait_generics.predicates { + if let hir::WherePredicate::BoundPredicate(pred) = p { + for b in pred.bounds { + if let hir::GenericBound::Outlives(lt) = b { + bounds_span.push(lt.ident.span); + } + } + } + } + if let Some(impl_node) = tcx.hir().get_if_local(impl_m.def_id) + && let Some(impl_generics) = impl_node.generics() + { + let mut impl_bounds = 0; + for p in impl_generics.predicates { + if let hir::WherePredicate::BoundPredicate(pred) = p { + for b in pred.bounds { + if let hir::GenericBound::Outlives(_) = b { + impl_bounds += 1; + } + } + } + } + if impl_bounds == bounds_span.len() { + bounds_span = vec![]; + } else if impl_generics.has_where_clause_predicates { + where_span = Some(impl_generics.where_clause_span); + } + } + } let reported = tcx .sess .create_err(LifetimesOrBoundsMismatchOnTrait { @@ -769,9 +797,10 @@ fn check_region_bounds_on_impl_item<'tcx>( item_kind: assoc_item_kind_str(impl_m), ident: impl_m.ident(tcx), generics_span, + bounds_span, + where_span, }) .emit_unless(delay); - return Err(reported); } diff --git a/compiler/rustc_hir_analysis/src/errors.rs b/compiler/rustc_hir_analysis/src/errors.rs index afbb27155a2..5156d432b5b 100644 --- a/compiler/rustc_hir_analysis/src/errors.rs +++ b/compiler/rustc_hir_analysis/src/errors.rs @@ -43,6 +43,10 @@ pub struct LifetimesOrBoundsMismatchOnTrait { pub span: Span, #[label(generics_label)] pub generics_span: Option<Span>, + #[label(where_label)] + pub where_span: Option<Span>, + #[label(bounds_label)] + pub bounds_span: Vec<Span>, pub item_kind: &'static str, pub ident: Ident, } diff --git a/src/test/ui/trait-bounds/impl-missing-where-clause-lifetimes-from-trait.rs b/src/test/ui/trait-bounds/impl-missing-where-clause-lifetimes-from-trait.rs new file mode 100644 index 00000000000..1994120ce14 --- /dev/null +++ b/src/test/ui/trait-bounds/impl-missing-where-clause-lifetimes-from-trait.rs @@ -0,0 +1,30 @@ +trait Trait<T> { + fn foo<'a, K>(self, _: T, _: K) where T: 'a, K: 'a; +} + +impl Trait<()> for () { + fn foo<'a, K>(self, _: (), _: K) where { //~ ERROR E0195 + todo!(); + } +} + +struct State; + +trait Foo<T> { + fn foo<'a>(&self, state: &'a State) -> &'a T + where + T: 'a; +} + +impl<F, T> Foo<T> for F +where + F: Fn(&State) -> &T, +{ + fn foo<'a>(&self, state: &'a State) -> &'a T { //~ ERROR E0195 + self(state) + } +} + +fn main() { + ().foo((), ()); +} diff --git a/src/test/ui/trait-bounds/impl-missing-where-clause-lifetimes-from-trait.stderr b/src/test/ui/trait-bounds/impl-missing-where-clause-lifetimes-from-trait.stderr new file mode 100644 index 00000000000..3a02369e2ee --- /dev/null +++ b/src/test/ui/trait-bounds/impl-missing-where-clause-lifetimes-from-trait.stderr @@ -0,0 +1,27 @@ +error[E0195]: lifetime parameters or bounds on method `foo` do not match the trait declaration + --> $DIR/impl-missing-where-clause-lifetimes-from-trait.rs:6:11 + | +LL | fn foo<'a, K>(self, _: T, _: K) where T: 'a, K: 'a; + | ------- -- -- this bound might be missing in the impl + | | | + | | this bound might be missing in the impl + | lifetimes in impl do not match this method in trait +... +LL | fn foo<'a, K>(self, _: (), _: K) where { + | ^^^^^^^ lifetimes do not match method in trait + +error[E0195]: lifetime parameters or bounds on method `foo` do not match the trait declaration + --> $DIR/impl-missing-where-clause-lifetimes-from-trait.rs:23:11 + | +LL | fn foo<'a>(&self, state: &'a State) -> &'a T + | ---- lifetimes in impl do not match this method in trait +LL | where +LL | T: 'a; + | -- this bound might be missing in the impl +... +LL | fn foo<'a>(&self, state: &'a State) -> &'a T { + | ^^^^ lifetimes do not match method in trait + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0195`. |