diff options
22 files changed, 157 insertions, 34 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 2a586f810d6..9a728b1060f 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -1,3 +1,5 @@ +// ignore-tidy-filelength :( + mod ambiguity; pub mod on_unimplemented; pub mod suggestions; @@ -67,6 +69,7 @@ pub enum CandidateSimilarity { pub struct ImplCandidate<'tcx> { pub trait_ref: ty::TraitRef<'tcx>, pub similarity: CandidateSimilarity, + impl_def_id: DefId, } enum GetSafeTransmuteErrorAndReason { @@ -1331,6 +1334,7 @@ trait InferCtxtPrivExt<'tcx> { body_def_id: LocalDefId, err: &mut Diagnostic, other: bool, + param_env: ty::ParamEnv<'tcx>, ) -> bool; fn report_similar_impl_candidates_for_root_obligation( @@ -1918,8 +1922,9 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let imp = self.tcx.impl_trait_ref(def_id).unwrap().skip_binder(); - self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false) - .map(|similarity| ImplCandidate { trait_ref: imp, similarity }) + self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false).map( + |similarity| ImplCandidate { trait_ref: imp, similarity, impl_def_id: def_id }, + ) }) .collect(); if candidates.iter().any(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. })) { @@ -1938,7 +1943,82 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { body_def_id: LocalDefId, err: &mut Diagnostic, other: bool, + param_env: ty::ParamEnv<'tcx>, ) -> bool { + // If we have a single implementation, try to unify it with the trait ref + // that failed. This should uncover a better hint for what *is* implemented. + if let [single] = &impl_candidates { + if self.probe(|_| { + let ocx = ObligationCtxt::new(self); + let obligation_trait_ref = self.instantiate_binder_with_placeholders(trait_ref); + let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id); + let impl_trait_ref = ocx.normalize( + &ObligationCause::dummy(), + param_env, + ty::EarlyBinder::bind(single.trait_ref).instantiate(self.tcx, impl_args), + ); + + ocx.register_obligations( + self.tcx + .predicates_of(single.impl_def_id) + .instantiate(self.tcx, impl_args) + .into_iter() + .map(|(clause, _)| { + Obligation::new(self.tcx, ObligationCause::dummy(), param_env, clause) + }), + ); + if !ocx.select_where_possible().is_empty() { + return false; + } + + let mut terrs = vec![]; + for (obligation_arg, impl_arg) in + std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args) + { + if let Err(terr) = + ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg) + { + terrs.push(terr); + } + if !ocx.select_where_possible().is_empty() { + return false; + } + } + + // Literally nothing unified, just give up. + if terrs.len() == impl_trait_ref.args.len() { + return false; + } + + let cand = + self.resolve_vars_if_possible(impl_trait_ref).fold_with(&mut BottomUpFolder { + tcx: self.tcx, + ty_op: |ty| ty, + lt_op: |lt| lt, + ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()), + }); + err.highlighted_help(vec![ + (format!("the trait `{}` ", cand.print_only_trait_path()), Style::NoStyle), + ("is".to_string(), Style::Highlight), + (" implemented for `".to_string(), Style::NoStyle), + (cand.self_ty().to_string(), Style::Highlight), + ("`".to_string(), Style::NoStyle), + ]); + + if let [TypeError::Sorts(exp_found)] = &terrs[..] { + let exp_found = self.resolve_vars_if_possible(*exp_found); + err.help(format!( + "for that trait implementation, expected `{}`, found `{}`", + exp_found.expected, exp_found.found + )); + } + + true + }) { + return true; + } + } + let other = if other { "other " } else { "" }; let report = |candidates: Vec<TraitRef<'tcx>>, err: &mut Diagnostic| { if candidates.is_empty() { @@ -2062,9 +2142,11 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { }) .collect(); impl_candidates.sort_by_key(|cand| (cand.similarity, cand.trait_ref)); + let mut impl_candidates: Vec<_> = + impl_candidates.into_iter().map(|cand| cand.trait_ref).collect(); impl_candidates.dedup(); - report(impl_candidates.into_iter().map(|cand| cand.trait_ref).collect(), err) + report(impl_candidates, err) } fn report_similar_impl_candidates_for_root_obligation( @@ -2108,6 +2190,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { body_def_id, err, true, + obligation.param_env, ); } } @@ -2316,6 +2399,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { obligation.cause.body_id, &mut err, false, + obligation.param_env, ); } } @@ -3051,6 +3135,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { body_def_id, err, true, + obligation.param_env, ) { self.report_similar_impl_candidates_for_root_obligation( &obligation, diff --git a/tests/ui/const-generics/occurs-check/unused-substs-1.stderr b/tests/ui/const-generics/occurs-check/unused-substs-1.stderr index 51ef354e3ed..61d055e8084 100644 --- a/tests/ui/const-generics/occurs-check/unused-substs-1.stderr +++ b/tests/ui/const-generics/occurs-check/unused-substs-1.stderr @@ -4,7 +4,7 @@ error[E0277]: the trait bound `A<_>: Bar<_>` is not satisfied LL | let _ = A; | ^ the trait `Bar<_>` is not implemented for `A<_>` | - = help: the trait `Bar<N>` is implemented for `A<7>` + = help: the trait `Bar<_>` is implemented for `A<7>` note: required by a bound in `A` --> $DIR/unused-substs-1.rs:9:11 | diff --git a/tests/ui/generic-const-items/unsatisfied-bounds.stderr b/tests/ui/generic-const-items/unsatisfied-bounds.stderr index 2cee53431a4..14894cef770 100644 --- a/tests/ui/generic-const-items/unsatisfied-bounds.stderr +++ b/tests/ui/generic-const-items/unsatisfied-bounds.stderr @@ -17,6 +17,7 @@ LL | let () = K::<()>; | ^^ the trait `From<()>` is not implemented for `Infallible` | = help: the trait `From<!>` is implemented for `Infallible` + = help: for that trait implementation, expected `!`, found `()` note: required by a bound in `K` --> $DIR/unsatisfied-bounds.rs:12:17 | @@ -48,6 +49,7 @@ LL | let _ = <() as Trait<&'static str>>::B::<()>; | ^^ the trait `From<()>` is not implemented for `Infallible` | = help: the trait `From<!>` is implemented for `Infallible` + = help: for that trait implementation, expected `!`, found `()` note: required by a bound in `Trait::B` --> $DIR/unsatisfied-bounds.rs:21:21 | diff --git a/tests/ui/impl-trait/issues/issue-62742.stderr b/tests/ui/impl-trait/issues/issue-62742.stderr index d872291c870..8d969e8e0f3 100644 --- a/tests/ui/impl-trait/issues/issue-62742.stderr +++ b/tests/ui/impl-trait/issues/issue-62742.stderr @@ -4,7 +4,7 @@ error[E0277]: the trait bound `RawImpl<_>: Raw<_>` is not satisfied LL | WrongImpl::foo(0i32); | ^^^^^^^^^ the trait `Raw<_>` is not implemented for `RawImpl<_>` | - = help: the trait `Raw<[T]>` is implemented for `RawImpl<T>` + = help: the trait `Raw<[_]>` is implemented for `RawImpl<_>` note: required by a bound in `SafeImpl` --> $DIR/issue-62742.rs:26:35 | @@ -42,7 +42,8 @@ error[E0277]: the trait bound `RawImpl<()>: Raw<()>` is not satisfied LL | WrongImpl::<()>::foo(0i32); | ^^^^^^^^^^^^^^^ the trait `Raw<()>` is not implemented for `RawImpl<()>` | - = help: the trait `Raw<[T]>` is implemented for `RawImpl<T>` + = help: the trait `Raw<[()]>` is implemented for `RawImpl<()>` + = help: for that trait implementation, expected `[()]`, found `()` note: required by a bound in `SafeImpl` --> $DIR/issue-62742.rs:26:35 | diff --git a/tests/ui/indexing/index-help.stderr b/tests/ui/indexing/index-help.stderr index e020d029875..2cb212a0139 100644 --- a/tests/ui/indexing/index-help.stderr +++ b/tests/ui/indexing/index-help.stderr @@ -5,7 +5,8 @@ LL | x[0i32]; | ^^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[{integer}]>` is not implemented for `i32` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[{integer}]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `i32` = note: required for `Vec<{integer}>` to implement `Index<i32>` error: aborting due to previous error diff --git a/tests/ui/indexing/indexing-requires-a-uint.stderr b/tests/ui/indexing/indexing-requires-a-uint.stderr index 7a741cfc7de..6ea6bb600e9 100644 --- a/tests/ui/indexing/indexing-requires-a-uint.stderr +++ b/tests/ui/indexing/indexing-requires-a-uint.stderr @@ -5,7 +5,8 @@ LL | [0][0u8]; | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[{integer}]>` is not implemented for `u8` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[{integer}]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `u8` = note: required for `[{integer}]` to implement `Index<u8>` error[E0308]: mismatched types diff --git a/tests/ui/integral-indexing.stderr b/tests/ui/integral-indexing.stderr index bbbb2a86a22..97e658617cf 100644 --- a/tests/ui/integral-indexing.stderr +++ b/tests/ui/integral-indexing.stderr @@ -5,7 +5,8 @@ LL | v[3u8]; | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[isize]>` is not implemented for `u8` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[isize]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `u8` = note: required for `Vec<isize>` to implement `Index<u8>` error[E0277]: the type `[isize]` cannot be indexed by `i8` @@ -15,7 +16,8 @@ LL | v[3i8]; | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[isize]>` is not implemented for `i8` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[isize]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `i8` = note: required for `Vec<isize>` to implement `Index<i8>` error[E0277]: the type `[isize]` cannot be indexed by `u32` @@ -25,7 +27,8 @@ LL | v[3u32]; | ^^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[isize]>` is not implemented for `u32` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[isize]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `u32` = note: required for `Vec<isize>` to implement `Index<u32>` error[E0277]: the type `[isize]` cannot be indexed by `i32` @@ -35,7 +38,8 @@ LL | v[3i32]; | ^^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[isize]>` is not implemented for `i32` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[isize]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `i32` = note: required for `Vec<isize>` to implement `Index<i32>` error[E0277]: the type `[u8]` cannot be indexed by `u8` @@ -45,7 +49,8 @@ LL | s.as_bytes()[3u8]; | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[u8]>` is not implemented for `u8` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[u8]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `u8` = note: required for `[u8]` to implement `Index<u8>` error[E0277]: the type `[u8]` cannot be indexed by `i8` @@ -55,7 +60,8 @@ LL | s.as_bytes()[3i8]; | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[u8]>` is not implemented for `i8` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[u8]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `i8` = note: required for `[u8]` to implement `Index<i8>` error[E0277]: the type `[u8]` cannot be indexed by `u32` @@ -65,7 +71,8 @@ LL | s.as_bytes()[3u32]; | ^^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[u8]>` is not implemented for `u32` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[u8]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `u32` = note: required for `[u8]` to implement `Index<u32>` error[E0277]: the type `[u8]` cannot be indexed by `i32` @@ -75,7 +82,8 @@ LL | s.as_bytes()[3i32]; | ^^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[u8]>` is not implemented for `i32` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[u8]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `i32` = note: required for `[u8]` to implement `Index<i32>` error: aborting due to 8 previous errors diff --git a/tests/ui/issues/issue-34334.stderr b/tests/ui/issues/issue-34334.stderr index 9d2c315e4db..753942dd1d1 100644 --- a/tests/ui/issues/issue-34334.stderr +++ b/tests/ui/issues/issue-34334.stderr @@ -19,7 +19,8 @@ LL | let sr2: Vec<(u32, _, _)> = sr.iter().map(|(faction, th_sender, th_rece | ^^^^^^^ value of type `Vec<(u32, _, _)>` cannot be built from `std::iter::Iterator<Item=()>` | = help: the trait `FromIterator<()>` is not implemented for `Vec<(u32, _, _)>` - = help: the trait `FromIterator<T>` is implemented for `Vec<T>` + = help: the trait `FromIterator<(u32, _, _)>` is implemented for `Vec<(u32, _, _)>` + = help: for that trait implementation, expected `(u32, _, _)`, found `()` note: the method call chain might not have had the expected associated types --> $DIR/issue-34334.rs:5:43 | diff --git a/tests/ui/issues/issue-45801.stderr b/tests/ui/issues/issue-45801.stderr index 8967f49df02..e651e2a68d1 100644 --- a/tests/ui/issues/issue-45801.stderr +++ b/tests/ui/issues/issue-45801.stderr @@ -5,6 +5,7 @@ LL | req.get_ref::<Params>(); | ^^^^^^^ the trait `Plugin<i32>` is not implemented for `Params` | = help: the trait `Plugin<Foo>` is implemented for `Params` + = help: for that trait implementation, expected `Foo`, found `i32` error: aborting due to previous error diff --git a/tests/ui/issues/issue-66923-show-error-for-correct-call.stderr b/tests/ui/issues/issue-66923-show-error-for-correct-call.stderr index 22b1da64cb3..128288e28f5 100644 --- a/tests/ui/issues/issue-66923-show-error-for-correct-call.stderr +++ b/tests/ui/issues/issue-66923-show-error-for-correct-call.stderr @@ -5,7 +5,8 @@ LL | let x2: Vec<f64> = x1.into_iter().collect(); | ^^^^^^^ value of type `Vec<f64>` cannot be built from `std::iter::Iterator<Item=&f64>` | = help: the trait `FromIterator<&f64>` is not implemented for `Vec<f64>` - = help: the trait `FromIterator<T>` is implemented for `Vec<T>` + = help: the trait `FromIterator<f64>` is implemented for `Vec<f64>` + = help: for that trait implementation, expected `f64`, found `&f64` note: the method call chain might not have had the expected associated types --> $DIR/issue-66923-show-error-for-correct-call.rs:8:27 | @@ -25,7 +26,8 @@ LL | let x3 = x1.into_iter().collect::<Vec<f64>>(); | required by a bound introduced by this call | = help: the trait `FromIterator<&f64>` is not implemented for `Vec<f64>` - = help: the trait `FromIterator<T>` is implemented for `Vec<T>` + = help: the trait `FromIterator<f64>` is implemented for `Vec<f64>` + = help: for that trait implementation, expected `f64`, found `&f64` note: the method call chain might not have had the expected associated types --> $DIR/issue-66923-show-error-for-correct-call.rs:12:17 | diff --git a/tests/ui/iterators/invalid-iterator-chain.stderr b/tests/ui/iterators/invalid-iterator-chain.stderr index b355da5cb76..2601c9c0d69 100644 --- a/tests/ui/iterators/invalid-iterator-chain.stderr +++ b/tests/ui/iterators/invalid-iterator-chain.stderr @@ -5,7 +5,8 @@ LL | i.collect() | ^^^^^^^ value of type `Vec<X>` cannot be built from `std::iter::Iterator<Item=&X>` | = help: the trait `FromIterator<&X>` is not implemented for `Vec<X>` - = help: the trait `FromIterator<T>` is implemented for `Vec<T>` + = help: the trait `FromIterator<X>` is implemented for `Vec<X>` + = help: for that trait implementation, expected `X`, found `&X` note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:4:26 | @@ -159,7 +160,8 @@ LL | let g: Vec<i32> = f.collect(); | ^^^^^^^ value of type `Vec<i32>` cannot be built from `std::iter::Iterator<Item=()>` | = help: the trait `FromIterator<()>` is not implemented for `Vec<i32>` - = help: the trait `FromIterator<T>` is implemented for `Vec<T>` + = help: the trait `FromIterator<i32>` is implemented for `Vec<i32>` + = help: for that trait implementation, expected `i32`, found `()` note: the method call chain might not have had the expected associated types --> $DIR/invalid-iterator-chain.rs:44:15 | diff --git a/tests/ui/never_type/never-value-fallback-issue-66757.nofallback.stderr b/tests/ui/never_type/never-value-fallback-issue-66757.nofallback.stderr index 54c16230fe6..cb378630589 100644 --- a/tests/ui/never_type/never-value-fallback-issue-66757.nofallback.stderr +++ b/tests/ui/never_type/never-value-fallback-issue-66757.nofallback.stderr @@ -5,6 +5,7 @@ LL | <E as From<_>>::from(never); | ^ the trait `From<()>` is not implemented for `E` | = help: the trait `From<!>` is implemented for `E` + = help: for that trait implementation, expected `!`, found `()` error: aborting due to previous error diff --git a/tests/ui/on-unimplemented/impl-substs.stderr b/tests/ui/on-unimplemented/impl-substs.stderr index a0fad0acd0b..36d80f3e681 100644 --- a/tests/ui/on-unimplemented/impl-substs.stderr +++ b/tests/ui/on-unimplemented/impl-substs.stderr @@ -7,7 +7,8 @@ LL | Foo::<usize>::foo((1i32, 1i32, 1i32)); | required by a bound introduced by this call | = help: the trait `Foo<usize>` is not implemented for `(i32, i32, i32)` - = help: the trait `Foo<A>` is implemented for `(A, B, C)` + = help: the trait `Foo<i32>` is implemented for `(i32, i32, i32)` + = help: for that trait implementation, expected `i32`, found `usize` error: aborting due to previous error diff --git a/tests/ui/on-unimplemented/on-impl.stderr b/tests/ui/on-unimplemented/on-impl.stderr index 2253c5992a6..3a0b8353fa5 100644 --- a/tests/ui/on-unimplemented/on-impl.stderr +++ b/tests/ui/on-unimplemented/on-impl.stderr @@ -8,6 +8,7 @@ LL | Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32); | = help: the trait `Index<u32>` is not implemented for `[i32]` = help: the trait `Index<usize>` is implemented for `[i32]` + = help: for that trait implementation, expected `usize`, found `u32` error[E0277]: the trait bound `[i32]: Index<u32>` is not satisfied --> $DIR/on-impl.rs:22:5 @@ -17,6 +18,7 @@ LL | Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32); | = help: the trait `Index<u32>` is not implemented for `[i32]` = help: the trait `Index<usize>` is implemented for `[i32]` + = help: for that trait implementation, expected `usize`, found `u32` error[E0277]: the trait bound `[i32]: Index<u32>` is not satisfied --> $DIR/on-impl.rs:22:5 @@ -26,6 +28,7 @@ LL | Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32); | = help: the trait `Index<u32>` is not implemented for `[i32]` = help: the trait `Index<usize>` is implemented for `[i32]` + = help: for that trait implementation, expected `usize`, found `u32` error: aborting due to 3 previous errors diff --git a/tests/ui/on-unimplemented/slice-index.stderr b/tests/ui/on-unimplemented/slice-index.stderr index b9bca211f43..5e0117be529 100644 --- a/tests/ui/on-unimplemented/slice-index.stderr +++ b/tests/ui/on-unimplemented/slice-index.stderr @@ -5,7 +5,8 @@ LL | x[1i32]; | ^^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[i32]>` is not implemented for `i32` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[i32]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `i32` = note: required for `[i32]` to implement `Index<i32>` error[E0277]: the type `[i32]` cannot be indexed by `RangeTo<i32>` diff --git a/tests/ui/str/str-idx.stderr b/tests/ui/str/str-idx.stderr index cb1a6fcacfc..e8bbb8058fa 100644 --- a/tests/ui/str/str-idx.stderr +++ b/tests/ui/str/str-idx.stderr @@ -7,7 +7,8 @@ LL | let _: u8 = s[4]; = help: the trait `SliceIndex<str>` is not implemented for `{integer}` = note: you can use `.chars().nth()` or `.bytes().nth()` for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings> - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[_]>` is implemented for `usize` + = help: for that trait implementation, expected `[_]`, found `str` = note: required for `str` to implement `Index<{integer}>` error[E0277]: the type `str` cannot be indexed by `{integer}` @@ -21,7 +22,8 @@ LL | let _ = s.get(4); = help: the trait `SliceIndex<str>` is not implemented for `{integer}` = note: you can use `.chars().nth()` or `.bytes().nth()` for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings> - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[_]>` is implemented for `usize` + = help: for that trait implementation, expected `[_]`, found `str` note: required by a bound in `core::str::<impl str>::get` --> $SRC_DIR/core/src/str/mod.rs:LL:COL @@ -36,7 +38,8 @@ LL | let _ = s.get_unchecked(4); = help: the trait `SliceIndex<str>` is not implemented for `{integer}` = note: you can use `.chars().nth()` or `.bytes().nth()` for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings> - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[_]>` is implemented for `usize` + = help: for that trait implementation, expected `[_]`, found `str` note: required by a bound in `core::str::<impl str>::get_unchecked` --> $SRC_DIR/core/src/str/mod.rs:LL:COL diff --git a/tests/ui/str/str-mut-idx.stderr b/tests/ui/str/str-mut-idx.stderr index ca4b86ba306..e6835bb54fb 100644 --- a/tests/ui/str/str-mut-idx.stderr +++ b/tests/ui/str/str-mut-idx.stderr @@ -31,7 +31,8 @@ LL | s[1usize] = bot(); | ^^^^^^ string indices are ranges of `usize` | = help: the trait `SliceIndex<str>` is not implemented for `usize` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[_]>` is implemented for `usize` + = help: for that trait implementation, expected `[_]`, found `str` = note: required for `str` to implement `Index<usize>` error[E0277]: the type `str` cannot be indexed by `{integer}` @@ -45,7 +46,8 @@ LL | s.get_mut(1); = help: the trait `SliceIndex<str>` is not implemented for `{integer}` = note: you can use `.chars().nth()` or `.bytes().nth()` for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings> - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[_]>` is implemented for `usize` + = help: for that trait implementation, expected `[_]`, found `str` note: required by a bound in `core::str::<impl str>::get_mut` --> $SRC_DIR/core/src/str/mod.rs:LL:COL @@ -60,7 +62,8 @@ LL | s.get_unchecked_mut(1); = help: the trait `SliceIndex<str>` is not implemented for `{integer}` = note: you can use `.chars().nth()` or `.bytes().nth()` for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings> - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[_]>` is implemented for `usize` + = help: for that trait implementation, expected `[_]`, found `str` note: required by a bound in `core::str::<impl str>::get_unchecked_mut` --> $SRC_DIR/core/src/str/mod.rs:LL:COL diff --git a/tests/ui/suggestions/issue-101623.stderr b/tests/ui/suggestions/issue-101623.stderr index 361483cc08d..9f00de17484 100644 --- a/tests/ui/suggestions/issue-101623.stderr +++ b/tests/ui/suggestions/issue-101623.stderr @@ -7,7 +7,8 @@ LL | Trait::do_stuff({ fun(&mut *inner) }); | | the trait `Trait<'_>` is not implemented for `*mut ()` | required by a bound introduced by this call | - = help: the trait `Trait<'a>` is implemented for `()` + = help: the trait `Trait<'_>` is implemented for `()` + = help: for that trait implementation, expected `()`, found `*mut ()` error: aborting due to previous error diff --git a/tests/ui/suggestions/suggest-dereferencing-index.stderr b/tests/ui/suggestions/suggest-dereferencing-index.stderr index 147dc9234c5..adf01339972 100644 --- a/tests/ui/suggestions/suggest-dereferencing-index.stderr +++ b/tests/ui/suggestions/suggest-dereferencing-index.stderr @@ -5,7 +5,8 @@ LL | let one_item_please: i32 = [1, 2, 3][i]; | ^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[{integer}]>` is not implemented for `&usize` - = help: the trait `SliceIndex<[T]>` is implemented for `usize` + = help: the trait `SliceIndex<[{integer}]>` is implemented for `usize` + = help: for that trait implementation, expected `usize`, found `&usize` = note: required for `[{integer}]` to implement `Index<&usize>` help: dereference this index | diff --git a/tests/ui/traits/coercion-generic-bad.stderr b/tests/ui/traits/coercion-generic-bad.stderr index e7e8a796796..30a3c40db95 100644 --- a/tests/ui/traits/coercion-generic-bad.stderr +++ b/tests/ui/traits/coercion-generic-bad.stderr @@ -5,6 +5,7 @@ LL | let s: Box<dyn Trait<isize>> = Box::new(Struct { person: "Fred" }); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait<isize>` is not implemented for `Struct` | = help: the trait `Trait<&'static str>` is implemented for `Struct` + = help: for that trait implementation, expected `&'static str`, found `isize` = note: required for the cast from `Box<Struct>` to `Box<dyn Trait<isize>>` error: aborting due to previous error diff --git a/tests/ui/try-block/try-block-bad-type.stderr b/tests/ui/try-block/try-block-bad-type.stderr index e11c3f81003..b41bf86d3d9 100644 --- a/tests/ui/try-block/try-block-bad-type.stderr +++ b/tests/ui/try-block/try-block-bad-type.stderr @@ -6,6 +6,7 @@ LL | Err("")?; | = note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait = help: the trait `From<Infallible>` is implemented for `TryFromSliceError` + = help: for that trait implementation, expected `Infallible`, found `&str` = note: required for `Result<u32, TryFromSliceError>` to implement `FromResidual<Result<Infallible, &str>>` error[E0271]: type mismatch resolving `<Result<i32, i32> as Try>::Output == &str` diff --git a/tests/ui/try-trait/bad-interconversion.stderr b/tests/ui/try-trait/bad-interconversion.stderr index 7eb392faa66..d8b9431becc 100644 --- a/tests/ui/try-trait/bad-interconversion.stderr +++ b/tests/ui/try-trait/bad-interconversion.stderr @@ -73,7 +73,8 @@ LL | ControlFlow::Continue(Err("hello")?) | ^ this `?` produces `Result<Infallible, &str>`, which is incompatible with `ControlFlow<String>` | = help: the trait `FromResidual<Result<Infallible, &str>>` is not implemented for `ControlFlow<String>` - = help: the trait `FromResidual` is implemented for `ControlFlow<B, C>` + = help: the trait `FromResidual<ControlFlow<String, Infallible>>` is implemented for `ControlFlow<String>` + = help: for that trait implementation, expected `ControlFlow<String, Infallible>`, found `Result<Infallible, &str>` error[E0277]: the `?` operator can only be used on `ControlFlow`s in a function that returns `ControlFlow` --> $DIR/bad-interconversion.rs:37:12 @@ -84,7 +85,8 @@ LL | Some(3)?; | ^ this `?` produces `Option<Infallible>`, which is incompatible with `ControlFlow<u64>` | = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `ControlFlow<u64>` - = help: the trait `FromResidual` is implemented for `ControlFlow<B, C>` + = help: the trait `FromResidual<ControlFlow<u64, Infallible>>` is implemented for `ControlFlow<u64>` + = help: for that trait implementation, expected `ControlFlow<u64, Infallible>`, found `Option<Infallible>` error[E0277]: the `?` operator in a function that returns `ControlFlow<B, _>` can only be used on other `ControlFlow<B, _>`s (with the same Break type) --> $DIR/bad-interconversion.rs:43:29 @@ -96,7 +98,8 @@ LL | ControlFlow::Break(4_u8)?; | = help: the trait `FromResidual<ControlFlow<u8, Infallible>>` is not implemented for `ControlFlow<i64>` = note: unlike `Result`, there's no `From`-conversion performed for `ControlFlow` - = help: the trait `FromResidual` is implemented for `ControlFlow<B, C>` + = help: the trait `FromResidual<ControlFlow<i64, Infallible>>` is implemented for `ControlFlow<i64>` + = help: for that trait implementation, expected `i64`, found `u8` error: aborting due to 8 previous errors |