diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs')
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs | 137 |
1 files changed, 109 insertions, 28 deletions
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 66d74fd05..fb75ec767 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -1,7 +1,7 @@ // ignore-tidy-filelength use super::{ - DefIdOrName, FindExprBySpan, Obligation, ObligationCause, ObligationCauseCode, + DefIdOrName, FindExprBySpan, ImplCandidate, Obligation, ObligationCause, ObligationCauseCode, PredicateObligation, }; @@ -30,7 +30,7 @@ use rustc_middle::hir::map; use rustc_middle::ty::error::TypeError::{self, Sorts}; use rustc_middle::ty::relate::TypeRelation; use rustc_middle::ty::{ - self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, DefIdTree, + self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, GeneratorDiagnosticData, GeneratorInteriorTypeCause, Infer, InferTy, InternalSubsts, IsSuggestable, ToPredicate, Ty, TyCtxt, TypeAndMut, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt, TypeckResults, @@ -212,7 +212,7 @@ pub trait TypeErrCtxtExt<'tcx> { fn extract_callable_info( &self, - hir_id: HirId, + body_id: LocalDefId, param_env: ty::ParamEnv<'tcx>, found: Ty<'tcx>, ) -> Option<(DefIdOrName, Ty<'tcx>, Vec<Ty<'tcx>>)>; @@ -382,6 +382,14 @@ pub trait TypeErrCtxtExt<'tcx> { body_id: hir::HirId, param_env: ty::ParamEnv<'tcx>, ) -> Vec<Option<(Span, (DefId, Ty<'tcx>))>>; + + fn maybe_suggest_convert_to_slice( + &self, + err: &mut Diagnostic, + trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + candidate_impls: &[ImplCandidate<'tcx>], + span: Span, + ); } fn predicate_constraint(generics: &hir::Generics<'_>, pred: ty::Predicate<'_>) -> (Span, String) { @@ -412,6 +420,7 @@ fn suggest_restriction<'tcx>( ) { if hir_generics.where_clause_span.from_expansion() || hir_generics.where_clause_span.desugaring_kind().is_some() + || projection.map_or(false, |projection| tcx.opt_rpitit_info(projection.def_id).is_some()) { return; } @@ -900,9 +909,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { trait_pred.self_ty(), ); - let body_hir_id = self.tcx.hir().local_def_id_to_hir_id(obligation.cause.body_id); let Some((def_id_or_name, output, inputs)) = self.extract_callable_info( - body_hir_id, + obligation.cause.body_id, obligation.param_env, self_ty, ) else { return false; }; @@ -1104,10 +1112,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { /// Extracts information about a callable type for diagnostics. This is a /// heuristic -- it doesn't necessarily mean that a type is always callable, /// because the callable type must also be well-formed to be called. - // FIXME(vincenzopalazzo): move the HirId to a LocalDefId fn extract_callable_info( &self, - hir_id: HirId, + body_id: LocalDefId, param_env: ty::ParamEnv<'tcx>, found: Ty<'tcx>, ) -> Option<(DefIdOrName, Ty<'tcx>, Vec<Ty<'tcx>>)> { @@ -1159,7 +1166,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { }) } ty::Param(param) => { - let generics = self.tcx.generics_of(hir_id.owner.to_def_id()); + let generics = self.tcx.generics_of(body_id); let name = if generics.count() > param.index as usize && let def = generics.param_at(param.index as usize, self.tcx) && matches!(def.kind, ty::GenericParamDefKind::Type { .. }) @@ -1349,6 +1356,31 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { Applicability::MaybeIncorrect, ); } else { + let is_mut = mut_ref_self_ty_satisfies_pred || ref_inner_ty_mut; + let sugg_prefix = format!("&{}", if is_mut { "mut " } else { "" }); + let sugg_msg = &format!( + "consider{} borrowing here", + if is_mut { " mutably" } else { "" } + ); + + // Issue #109436, we need to add parentheses properly for method calls + // for example, `foo.into()` should be `(&foo).into()` + if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet( + self.tcx.sess.source_map().span_look_ahead(span, Some("."), Some(50)), + ) { + if snippet == "." { + err.multipart_suggestion_verbose( + sugg_msg, + vec![ + (span.shrink_to_lo(), format!("({}", sugg_prefix)), + (span.shrink_to_hi(), ")".to_string()), + ], + Applicability::MaybeIncorrect, + ); + return true; + } + } + // Issue #104961, we need to add parentheses properly for compond expressions // for example, `x.starts_with("hi".to_string() + "you")` // should be `x.starts_with(&("hi".to_string() + "you"))` @@ -1365,14 +1397,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { _ => false, }; - let is_mut = mut_ref_self_ty_satisfies_pred || ref_inner_ty_mut; let span = if needs_parens { span } else { span.shrink_to_lo() }; - let sugg_prefix = format!("&{}", if is_mut { "mut " } else { "" }); - let sugg_msg = &format!( - "consider{} borrowing here", - if is_mut { " mutably" } else { "" } - ); - let suggestions = if !needs_parens { vec![(span.shrink_to_lo(), format!("{}", sugg_prefix))] } else { @@ -2220,7 +2245,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // - `BuiltinDerivedObligation` with a generator witness (A) // - `BuiltinDerivedObligation` with a generator (A) // - `BuiltinDerivedObligation` with `impl std::future::Future` (A) - // - `BindingObligation` with `impl_send (Send requirement) + // - `BindingObligation` with `impl_send` (Send requirement) // // The first obligation in the chain is the most useful and has the generator that captured // the type. The last generator (`outer_generator` below) has information about where the @@ -2936,9 +2961,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ObligationCauseCode::SizedYieldType => { err.note("the yield type of a generator must have a statically known size"); } - ObligationCauseCode::SizedBoxType => { - err.note("the type of a box expression must have a statically known size"); - } ObligationCauseCode::AssignmentLhsSized => { err.note("the left-hand-side of an assignment must have a statically known size"); } @@ -3025,8 +3047,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } }; - let identity_future = tcx.require_lang_item(LangItem::IdentityFuture, None); - // Don't print the tuple of capture types 'print: { if !is_upvar_tys_infer_tuple { @@ -3039,12 +3059,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { None => err.note(&msg), }, ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) => { - // Avoid printing the future from `core::future::identity_future`, it's not helpful - if tcx.parent(*def_id) == identity_future { - break 'print; - } - - // If the previous type is `identity_future`, this is the future generated by the body of an async function. + // If the previous type is async fn, this is the future generated by the body of an async function. // Avoid printing it twice (it was already printed in the `ty::Generator` arm below). let is_future = tcx.ty_is_opaque_future(ty); debug!( @@ -3826,6 +3841,72 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } assocs_in_this_method } + + /// If the type that failed selection is an array or a reference to an array, + /// but the trait is implemented for slices, suggest that the user converts + /// the array into a slice. + fn maybe_suggest_convert_to_slice( + &self, + err: &mut Diagnostic, + trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + candidate_impls: &[ImplCandidate<'tcx>], + span: Span, + ) { + // Three cases where we can make a suggestion: + // 1. `[T; _]` (array of T) + // 2. `&[T; _]` (reference to array of T) + // 3. `&mut [T; _]` (mutable reference to array of T) + let (element_ty, mut mutability) = match *trait_ref.skip_binder().self_ty().kind() { + ty::Array(element_ty, _) => (element_ty, None), + + ty::Ref(_, pointee_ty, mutability) => match *pointee_ty.kind() { + ty::Array(element_ty, _) => (element_ty, Some(mutability)), + _ => return, + }, + + _ => return, + }; + + // Go through all the candidate impls to see if any of them is for + // slices of `element_ty` with `mutability`. + let mut is_slice = |candidate: Ty<'tcx>| match *candidate.kind() { + ty::RawPtr(ty::TypeAndMut { ty: t, mutbl: m }) | ty::Ref(_, t, m) => { + if matches!(*t.kind(), ty::Slice(e) if e == element_ty) + && m == mutability.unwrap_or(m) + { + // Use the candidate's mutability going forward. + mutability = Some(m); + true + } else { + false + } + } + _ => false, + }; + + // Grab the first candidate that matches, if any, and make a suggestion. + if let Some(slice_ty) = candidate_impls + .iter() + .map(|trait_ref| trait_ref.trait_ref.self_ty()) + .find(|t| is_slice(*t)) + { + let msg = &format!("convert the array to a `{}` slice instead", slice_ty); + + if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) { + let mut suggestions = vec![]; + if snippet.starts_with('&') { + } else if let Some(hir::Mutability::Mut) = mutability { + suggestions.push((span.shrink_to_lo(), "&mut ".into())); + } else { + suggestions.push((span.shrink_to_lo(), "&".into())); + } + suggestions.push((span.shrink_to_hi(), "[..]".into())); + err.multipart_suggestion_verbose(msg, suggestions, Applicability::MaybeIncorrect); + } else { + err.span_help(span, msg); + } + } + } } /// Add a hint to add a missing borrow or remove an unnecessary one. @@ -3854,7 +3935,7 @@ fn hint_missing_borrow<'tcx>( // This could be a variant constructor, for example. let Some(fn_decl) = found_node.fn_decl() else { return; }; - let args = fn_decl.inputs.iter().map(|ty| ty); + let args = fn_decl.inputs.iter(); fn get_deref_type_and_refs(mut ty: Ty<'_>) -> (Ty<'_>, Vec<hir::Mutability>) { let mut refs = vec![]; |