diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/astconv/errors.rs')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/astconv/errors.rs | 230 |
1 files changed, 228 insertions, 2 deletions
diff --git a/compiler/rustc_hir_analysis/src/astconv/errors.rs b/compiler/rustc_hir_analysis/src/astconv/errors.rs index 232ef2079d6..a9c2886b414 100644 --- a/compiler/rustc_hir_analysis/src/astconv/errors.rs +++ b/compiler/rustc_hir_analysis/src/astconv/errors.rs @@ -1,10 +1,11 @@ use crate::astconv::AstConv; use crate::errors::{ManualImplementation, MissingTypeParams}; use rustc_data_structures::fx::FxHashMap; -use rustc_errors::{pluralize, struct_span_err, Applicability, ErrorGuaranteed}; +use rustc_errors::{pluralize, struct_span_err, Applicability, Diagnostic, ErrorGuaranteed}; use rustc_hir as hir; use rustc_hir::def_id::DefId; -use rustc_middle::ty; +use rustc_infer::traits::FulfillmentError; +use rustc_middle::ty::{self, Ty}; use rustc_session::parse::feature_err; use rustc_span::lev_distance::find_best_match_for_name; use rustc_span::symbol::{sym, Ident}; @@ -221,6 +222,231 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { err.emit() } + pub(crate) fn complain_about_ambiguous_inherent_assoc_type( + &self, + name: Ident, + candidates: Vec<DefId>, + span: Span, + ) -> ErrorGuaranteed { + let mut err = struct_span_err!( + self.tcx().sess, + name.span, + E0034, + "multiple applicable items in scope" + ); + err.span_label(name.span, format!("multiple `{name}` found")); + self.note_ambiguous_inherent_assoc_type(&mut err, candidates, span); + err.emit() + } + + // FIXME(fmease): Heavily adapted from `rustc_hir_typeck::method::suggest`. Deduplicate. + fn note_ambiguous_inherent_assoc_type( + &self, + err: &mut Diagnostic, + candidates: Vec<DefId>, + span: Span, + ) { + let tcx = self.tcx(); + + // Dynamic limit to avoid hiding just one candidate, which is silly. + let limit = if candidates.len() == 5 { 5 } else { 4 }; + + for (index, &item) in candidates.iter().take(limit).enumerate() { + let impl_ = tcx.impl_of_method(item).unwrap(); + + let note_span = if item.is_local() { + Some(tcx.def_span(item)) + } else if impl_.is_local() { + Some(tcx.def_span(impl_)) + } else { + None + }; + + let title = if candidates.len() > 1 { + format!("candidate #{}", index + 1) + } else { + "the candidate".into() + }; + + let impl_ty = tcx.at(span).type_of(impl_).subst_identity(); + let note = format!("{title} is defined in an impl for the type `{impl_ty}`"); + + if let Some(span) = note_span { + err.span_note(span, ¬e); + } else { + err.note(¬e); + } + } + if candidates.len() > limit { + err.note(&format!("and {} others", candidates.len() - limit)); + } + } + + // FIXME(inherent_associated_types): Find similarly named associated types and suggest them. + pub(crate) fn complain_about_inherent_assoc_type_not_found( + &self, + name: Ident, + self_ty: Ty<'tcx>, + candidates: Vec<(DefId, (DefId, DefId))>, + fulfillment_errors: Vec<FulfillmentError<'tcx>>, + span: Span, + ) -> ErrorGuaranteed { + // FIXME(fmease): This was copied in parts from an old version of `rustc_hir_typeck::method::suggest`. + // Either + // * update this code by applying changes similar to #106702 or by taking a + // Vec<(DefId, (DefId, DefId), Option<Vec<FulfillmentError<'tcx>>>)> or + // * deduplicate this code across the two crates. + + let tcx = self.tcx(); + + let adt_did = self_ty.ty_adt_def().map(|def| def.did()); + let add_def_label = |err: &mut Diagnostic| { + if let Some(did) = adt_did { + err.span_label( + tcx.def_span(did), + format!( + "associated item `{name}` not found for this {}", + tcx.def_kind(did).descr(did) + ), + ); + } + }; + + if fulfillment_errors.is_empty() { + // FIXME(fmease): Copied from `rustc_hir_typeck::method::probe`. Deduplicate. + + let limit = if candidates.len() == 5 { 5 } else { 4 }; + let type_candidates = candidates + .iter() + .take(limit) + .map(|&(impl_, _)| format!("- `{}`", tcx.at(span).type_of(impl_).subst_identity())) + .collect::<Vec<_>>() + .join("\n"); + let additional_types = if candidates.len() > limit { + format!("\nand {} more types", candidates.len() - limit) + } else { + String::new() + }; + + let mut err = struct_span_err!( + tcx.sess, + name.span, + E0220, + "associated type `{name}` not found for `{self_ty}` in the current scope" + ); + err.span_label(name.span, format!("associated item not found in `{self_ty}`")); + err.note(&format!( + "the associated type was found for\n{type_candidates}{additional_types}", + )); + add_def_label(&mut err); + return err.emit(); + } + + let mut bound_spans = Vec::new(); + + let mut bound_span_label = |self_ty: Ty<'_>, obligation: &str, quiet: &str| { + let msg = format!( + "doesn't satisfy `{}`", + if obligation.len() > 50 { quiet } else { obligation } + ); + match &self_ty.kind() { + // Point at the type that couldn't satisfy the bound. + ty::Adt(def, _) => bound_spans.push((tcx.def_span(def.did()), msg)), + // Point at the trait object that couldn't satisfy the bound. + ty::Dynamic(preds, _, _) => { + for pred in preds.iter() { + match pred.skip_binder() { + ty::ExistentialPredicate::Trait(tr) => { + bound_spans.push((tcx.def_span(tr.def_id), msg.clone())) + } + ty::ExistentialPredicate::Projection(_) + | ty::ExistentialPredicate::AutoTrait(_) => {} + } + } + } + // Point at the closure that couldn't satisfy the bound. + ty::Closure(def_id, _) => { + bound_spans.push((tcx.def_span(*def_id), format!("doesn't satisfy `{quiet}`"))) + } + _ => {} + } + }; + + let format_pred = |pred: ty::Predicate<'tcx>| { + let bound_predicate = pred.kind(); + match bound_predicate.skip_binder() { + ty::PredicateKind::Clause(ty::Clause::Projection(pred)) => { + let pred = bound_predicate.rebind(pred); + // `<Foo as Iterator>::Item = String`. + let projection_ty = pred.skip_binder().projection_ty; + + let substs_with_infer_self = tcx.mk_substs( + std::iter::once(tcx.mk_ty_var(ty::TyVid::from_u32(0)).into()) + .chain(projection_ty.substs.iter().skip(1)), + ); + + let quiet_projection_ty = + tcx.mk_alias_ty(projection_ty.def_id, substs_with_infer_self); + + let term = pred.skip_binder().term; + + let obligation = format!("{projection_ty} = {term}"); + let quiet = format!("{quiet_projection_ty} = {term}"); + + bound_span_label(projection_ty.self_ty(), &obligation, &quiet); + Some((obligation, projection_ty.self_ty())) + } + ty::PredicateKind::Clause(ty::Clause::Trait(poly_trait_ref)) => { + let p = poly_trait_ref.trait_ref; + let self_ty = p.self_ty(); + let path = p.print_only_trait_path(); + let obligation = format!("{self_ty}: {path}"); + let quiet = format!("_: {path}"); + bound_span_label(self_ty, &obligation, &quiet); + Some((obligation, self_ty)) + } + _ => None, + } + }; + + // FIXME(fmease): `rustc_hir_typeck::method::suggest` uses a `skip_list` to filter out some bounds. + // I would do the same here if it didn't mean more code duplication. + let mut bounds: Vec<_> = fulfillment_errors + .into_iter() + .map(|error| error.root_obligation.predicate) + .filter_map(format_pred) + .map(|(p, _)| format!("`{}`", p)) + .collect(); + bounds.sort(); + bounds.dedup(); + + let mut err = tcx.sess.struct_span_err( + name.span, + &format!("the associated type `{name}` exists for `{self_ty}`, but its trait bounds were not satisfied") + ); + if !bounds.is_empty() { + err.note(&format!( + "the following trait bounds were not satisfied:\n{}", + bounds.join("\n") + )); + } + err.span_label( + name.span, + format!("associated type cannot be referenced on `{self_ty}` due to unsatisfied trait bounds") + ); + + bound_spans.sort(); + bound_spans.dedup(); + for (span, msg) in bound_spans { + if !tcx.sess.source_map().is_span_accessible(span) { + continue; + } + err.span_label(span, &msg); + } + add_def_label(&mut err); + err.emit() + } + /// When there are any missing associated types, emit an E0191 error and attempt to supply a /// reasonable suggestion on how to write it. For the case of multiple associated types in the /// same trait bound have the same name (as they come from different supertraits), we instead |