diff options
7 files changed, 112 insertions, 0 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs index 135410691f1..7d754cbafa3 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -986,6 +986,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } + self.explain_hrtb_projection(&mut err, trait_predicate, obligation.param_env, &obligation.cause); + // Return early if the trait is Debug or Display and the invocation // originates within a standard library macro, because the output // is otherwise overwhelming and unhelpful (see #85844 for an 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 d6ac7208715..a08ebe5a9ea 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -406,6 +406,14 @@ pub trait TypeErrCtxtExt<'tcx> { candidate_impls: &[ImplCandidate<'tcx>], span: Span, ); + + fn explain_hrtb_projection( + &self, + diag: &mut Diagnostic, + pred: ty::PolyTraitPredicate<'tcx>, + param_env: ty::ParamEnv<'tcx>, + cause: &ObligationCause<'tcx>, + ); } fn predicate_constraint(generics: &hir::Generics<'_>, pred: ty::Predicate<'_>) -> (Span, String) { @@ -4027,6 +4035,71 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } } + + fn explain_hrtb_projection( + &self, + diag: &mut Diagnostic, + pred: ty::PolyTraitPredicate<'tcx>, + param_env: ty::ParamEnv<'tcx>, + cause: &ObligationCause<'tcx>, + ) { + if pred.skip_binder().has_escaping_bound_vars() && pred.skip_binder().has_non_region_infer() + { + self.probe(|_| { + let ocx = ObligationCtxt::new(self); + let pred = self.instantiate_binder_with_placeholders(pred); + let pred = ocx.normalize(&ObligationCause::dummy(), param_env, pred); + ocx.register_obligation(Obligation::new( + self.tcx, + ObligationCause::dummy(), + param_env, + pred, + )); + if !ocx.select_where_possible().is_empty() { + // encountered errors. + return; + } + + if let ObligationCauseCode::FunctionArgumentObligation { + call_hir_id, + arg_hir_id, + parent_code: _, + } = cause.code() + { + let arg_span = self.tcx.hir().span(*arg_hir_id); + let mut sp: MultiSpan = arg_span.into(); + + sp.push_span_label( + arg_span, + "the trait solver is unable to infer the \ + generic types that should be inferred from this argument", + ); + sp.push_span_label( + self.tcx.hir().span(*call_hir_id), + "add turbofish arguments to this call to \ + specify the types manually, even if it's redundant", + ); + diag.span_note( + sp, + "this is a known limitation of the trait solver that \ + will be lifted in the future", + ); + } else { + let mut sp: MultiSpan = cause.span.into(); + sp.push_span_label( + cause.span, + "try adding turbofish arguments to this expression to \ + specify the types manually, even if it's redundant", + ); + diag.span_note( + sp, + "this is a known limitation of the trait solver that \ + will be lifted in the future", + ); + } + }); + } + } } /// Add a hint to add a missing borrow or remove an unnecessary one. diff --git a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr index 3b63ec45804..8f45902035e 100644 --- a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr +++ b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr @@ -16,6 +16,14 @@ LL | build(Bar); | required by a bound introduced by this call | = help: the trait `for<'a> Send` is not implemented for `impl Future<Output = ()> { <_ as Foo>::bar() }` +note: this is a known limitation of the trait solver that will be lifted in the future + --> $DIR/normalizing-self-auto-trait-issue-109924.rs:23:11 + | +LL | build(Bar); + | ------^^^- + | | | + | | the trait solver is unable to infer the generic types that should be inferred from this argument + | add turbofish arguments to this call to specify the types manually, even if it's redundant note: required by a bound in `build` --> $DIR/normalizing-self-auto-trait-issue-109924.rs:20:39 | diff --git a/tests/ui/generic-associated-types/bugs/issue-88460.stderr b/tests/ui/generic-associated-types/bugs/issue-88460.stderr index a2047f103d4..b9e2c4186c1 100644 --- a/tests/ui/generic-associated-types/bugs/issue-88460.stderr +++ b/tests/ui/generic-associated-types/bugs/issue-88460.stderr @@ -7,6 +7,14 @@ LL | test(Foo); | required by a bound introduced by this call | = help: the trait `Marker` is implemented for `()` +note: this is a known limitation of the trait solver that will be lifted in the future + --> $DIR/issue-88460.rs:28:10 + | +LL | test(Foo); + | -----^^^- + | | | + | | the trait solver is unable to infer the generic types that should be inferred from this argument + | add turbofish arguments to this call to specify the types manually, even if it's redundant note: required by a bound in `test` --> $DIR/issue-88460.rs:15:27 | diff --git a/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-62529-3.stderr b/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-62529-3.stderr index b30dd36d2ad..2cc2bb2bbc3 100644 --- a/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-62529-3.stderr +++ b/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-62529-3.stderr @@ -8,6 +8,14 @@ LL | call(f, ()); | = note: expected a closure with arguments `((),)` found a closure with arguments `(<_ as ATC<'a>>::Type,)` +note: this is a known limitation of the trait solver that will be lifted in the future + --> $DIR/issue-62529-3.rs:25:14 + | +LL | call(f, ()); + | -----^----- + | | | + | | the trait solver is unable to infer the generic types that should be inferred from this argument + | add turbofish arguments to this call to specify the types manually, even if it's redundant note: required by a bound in `call` --> $DIR/issue-62529-3.rs:9:36 | diff --git a/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-90950.stderr b/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-90950.stderr index 5be33bccdc3..55eaef78634 100644 --- a/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-90950.stderr +++ b/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-90950.stderr @@ -7,6 +7,14 @@ LL | upcast(y) | required by a bound introduced by this call | = help: the trait `IsCovariant<'a>` is implemented for `std::borrow::Cow<'a, T>` +note: this is a known limitation of the trait solver that will be lifted in the future + --> $DIR/issue-90950.rs:50:12 + | +LL | upcast(y) + | -------^- + | | | + | | the trait solver is unable to infer the generic types that should be inferred from this argument + | add turbofish arguments to this call to specify the types manually, even if it's redundant note: required by a bound in `upcast` --> $DIR/issue-90950.rs:27:42 | diff --git a/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/norm-before-method-resolution.stderr b/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/norm-before-method-resolution.stderr index 73388a72574..081dbb67df8 100644 --- a/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/norm-before-method-resolution.stderr +++ b/tests/ui/higher-ranked/trait-bounds/normalize-under-binder/norm-before-method-resolution.stderr @@ -4,6 +4,11 @@ error[E0277]: the trait bound `for<'a> <_ as Trait<'a>>::Out: Copy` is not satis LL | let _: () = weird_bound(); | ^^^^^^^^^^^ the trait `for<'a> Copy` is not implemented for `<_ as Trait<'a>>::Out` | +note: this is a known limitation of the trait solver that will be lifted in the future + --> $DIR/norm-before-method-resolution.rs:22:17 + | +LL | let _: () = weird_bound(); + | ^^^^^^^^^^^ try adding turbofish arguments to this expression to specify the types manually, even if it's redundant note: required by a bound in `weird_bound` --> $DIR/norm-before-method-resolution.rs:18:40 | |