diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs')
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs | 206 |
1 files changed, 145 insertions, 61 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 e442c5c91..efdb1ace1 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -22,6 +22,7 @@ use rustc_hir::intravisit::Visitor; use rustc_hir::GenericParam; use rustc_hir::Item; use rustc_hir::Node; +use rustc_infer::infer::TypeTrace; use rustc_infer::traits::TraitEngine; use rustc_middle::traits::select::OverflowError; use rustc_middle::ty::abstract_const::NotConstEvaluatable; @@ -348,7 +349,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { message, label, note, - enclosing_scope, + parent_label, append_const_msg, } = self.on_unimplemented_note(trait_ref, &obligation); let have_alt_message = message.is_some() || label.is_some(); @@ -449,12 +450,27 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { { "consider using `()`, or a `Result`".to_owned() } else { - format!( - "{}the trait `{}` is not implemented for `{}`", - pre_message, - trait_predicate.print_modifiers_and_trait_path(), - trait_ref.skip_binder().self_ty(), - ) + let ty_desc = match trait_ref.skip_binder().self_ty().kind() { + ty::FnDef(_, _) => Some("fn item"), + ty::Closure(_, _) => Some("closure"), + _ => None, + }; + + match ty_desc { + Some(desc) => format!( + "{}the trait `{}` is not implemented for {} `{}`", + pre_message, + trait_predicate.print_modifiers_and_trait_path(), + desc, + trait_ref.skip_binder().self_ty(), + ), + None => format!( + "{}the trait `{}` is not implemented for `{}`", + pre_message, + trait_predicate.print_modifiers_and_trait_path(), + trait_ref.skip_binder().self_ty(), + ), + } }; if self.suggest_add_reference_to_arg( @@ -514,7 +530,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { // If it has a custom `#[rustc_on_unimplemented]` note, let's display it err.note(s.as_str()); } - if let Some(ref s) = enclosing_scope { + if let Some(ref s) = parent_label { let body = tcx .hir() .opt_local_def_id(obligation.cause.body_id) @@ -523,11 +539,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { hir_id: obligation.cause.body_id, }) }); - - let enclosing_scope_span = - tcx.hir().span_with_body(tcx.hir().local_def_id_to_hir_id(body)); - - err.span_label(enclosing_scope_span, s); + err.span_label(tcx.def_span(body), s); } self.suggest_floating_point_literal(&obligation, &mut err, &trait_ref); @@ -859,8 +871,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { } } - err.emit(); - return; + err } ty::PredicateKind::WellFormed(ty) => { @@ -941,9 +952,14 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { self.reported_closure_mismatch.borrow_mut().insert((span, found_span)); + let mut not_tupled = false; + let found = match found_trait_ref.skip_binder().substs.type_at(1).kind() { ty::Tuple(ref tys) => vec![ArgKind::empty(); tys.len()], - _ => vec![ArgKind::empty()], + _ => { + not_tupled = true; + vec![ArgKind::empty()] + } }; let expected_ty = expected_trait_ref.skip_binder().substs.type_at(1); @@ -951,10 +967,28 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { ty::Tuple(ref tys) => { tys.iter().map(|t| ArgKind::from_expected_ty(t, Some(span))).collect() } - _ => vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())], + _ => { + not_tupled = true; + vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())] + } }; - if found.len() == expected.len() { + // If this is a `Fn` family trait and either the expected or found + // is not tupled, then fall back to just a regular mismatch error. + // This shouldn't be common unless manually implementing one of the + // traits manually, but don't make it more confusing when it does + // happen. + if Some(expected_trait_ref.def_id()) != tcx.lang_items().gen_trait() && not_tupled { + self.report_and_explain_type_error( + TypeTrace::poly_trait_refs( + &obligation.cause, + true, + expected_trait_ref, + found_trait_ref, + ), + ty::error::TypeError::Mismatch, + ) + } else if found.len() == expected.len() { self.report_closure_arg_mismatch( span, found_span, @@ -1315,6 +1349,13 @@ trait InferCtxtPrivExt<'hir, 'tcx> { error: &MismatchedProjectionTypes<'tcx>, ); + fn maybe_detailed_projection_msg( + &self, + pred: ty::ProjectionPredicate<'tcx>, + normalized_ty: ty::Term<'tcx>, + expected_ty: ty::Term<'tcx>, + ) -> Option<String>; + fn fuzzy_match_tys( &self, a: Ty<'tcx>, @@ -1476,13 +1517,28 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { .emit(); } FulfillmentErrorCode::CodeConstEquateError(ref expected_found, ref err) => { - self.report_mismatched_consts( + let mut diag = self.report_mismatched_consts( &error.obligation.cause, expected_found.expected, expected_found.found, err.clone(), - ) - .emit(); + ); + let code = error.obligation.cause.code().peel_derives().peel_match_impls(); + if let ObligationCauseCode::BindingObligation(..) + | ObligationCauseCode::ItemObligation(..) + | ObligationCauseCode::ExprBindingObligation(..) + | ObligationCauseCode::ExprItemObligation(..) = code + { + self.note_obligation_cause_code( + &mut diag, + &error.obligation.predicate, + error.obligation.param_env, + code, + &mut vec![], + &mut Default::default(), + ); + } + diag.emit(); } } } @@ -1500,8 +1556,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { } self.probe(|_| { - let err_buf; - let mut err = &error.err; + let mut err = error.err; let mut values = None; // try to find the mismatched types to report the error with. @@ -1534,31 +1589,28 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { obligation.cause.code().peel_derives(), ObligationCauseCode::ItemObligation(_) | ObligationCauseCode::BindingObligation(_, _) + | ObligationCauseCode::ExprItemObligation(..) + | ObligationCauseCode::ExprBindingObligation(..) | ObligationCauseCode::ObjectCastObligation(..) | ObligationCauseCode::OpaqueType ); - if let Err(error) = self.at(&obligation.cause, obligation.param_env).eq_exp( + if let Err(new_err) = self.at(&obligation.cause, obligation.param_env).eq_exp( is_normalized_ty_expected, normalized_ty, data.term, ) { - values = Some(infer::ValuePairs::Terms(ExpectedFound::new( - is_normalized_ty_expected, - normalized_ty, - data.term, - ))); - err_buf = error; - err = &err_buf; + values = Some((data, is_normalized_ty_expected, normalized_ty, data.term)); + err = new_err; } } - let mut diag = struct_span_err!( - self.tcx.sess, - obligation.cause.span, - E0271, - "type mismatch resolving `{}`", - predicate - ); + let msg = values + .and_then(|(predicate, _, normalized_ty, expected_ty)| { + self.maybe_detailed_projection_msg(predicate, normalized_ty, expected_ty) + }) + .unwrap_or_else(|| format!("type mismatch resolving `{}`", predicate)); + let mut diag = struct_span_err!(self.tcx.sess, obligation.cause.span, E0271, "{msg}"); + let secondary_span = match predicate.kind().skip_binder() { ty::PredicateKind::Projection(proj) => self .tcx @@ -1596,7 +1648,13 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { &mut diag, &obligation.cause, secondary_span, - values, + values.map(|(_, is_normalized_ty_expected, normalized_ty, term)| { + infer::ValuePairs::Terms(ExpectedFound::new( + is_normalized_ty_expected, + normalized_ty, + term, + )) + }), err, true, false, @@ -1606,6 +1664,33 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { }); } + fn maybe_detailed_projection_msg( + &self, + pred: ty::ProjectionPredicate<'tcx>, + normalized_ty: ty::Term<'tcx>, + expected_ty: ty::Term<'tcx>, + ) -> Option<String> { + let trait_def_id = pred.projection_ty.trait_def_id(self.tcx); + let self_ty = pred.projection_ty.self_ty(); + + if Some(pred.projection_ty.item_def_id) == self.tcx.lang_items().fn_once_output() { + Some(format!( + "expected `{self_ty}` to be a {fn_kind} that returns `{expected_ty}`, but it returns `{normalized_ty}`", + fn_kind = self_ty.prefix_string(self.tcx) + )) + } else if Some(trait_def_id) == self.tcx.lang_items().future_trait() { + Some(format!( + "expected `{self_ty}` to be a future that resolves to `{expected_ty}`, but it resolves to `{normalized_ty}`" + )) + } else if Some(trait_def_id) == self.tcx.get_diagnostic_item(sym::Iterator) { + Some(format!( + "expected `{self_ty}` to be an iterator that yields `{expected_ty}`, but it yields `{normalized_ty}`" + )) + } else { + None + } + } + fn fuzzy_match_tys( &self, mut a: Ty<'tcx>, @@ -1731,13 +1816,21 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { return false; } if candidates.len() == 1 { + let ty_desc = match candidates[0].self_ty().kind() { + ty::FnPtr(_) => Some("fn pointer"), + _ => None, + }; + let the_desc = match ty_desc { + Some(desc) => format!(" implemented for {} `", desc), + None => " implemented for `".to_string(), + }; err.highlighted_help(vec![ ( format!("the trait `{}` ", candidates[0].print_only_trait_path()), Style::NoStyle, ), ("is".to_string(), Style::Highlight), - (" implemented for `".to_string(), Style::NoStyle), + (the_desc, Style::NoStyle), (candidates[0].self_ty().to_string(), Style::Highlight), ("`".to_string(), Style::NoStyle), ]); @@ -1802,9 +1895,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { // FIXME(compiler-errors): This could be generalized, both to // be more granular, and probably look past other `#[fundamental]` // types, too. - self.tcx - .visibility(def.did()) - .is_accessible_from(body_id.owner.to_def_id(), self.tcx) + self.tcx.visibility(def.did()).is_accessible_from(body_id.owner, self.tcx) } else { true } @@ -1940,7 +2031,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { let predicate = self.resolve_vars_if_possible(obligation.predicate); let span = obligation.cause.span; - debug!(?predicate, obligation.cause.code = tracing::field::debug(&obligation.cause.code())); + debug!(?predicate, obligation.cause.code = ?obligation.cause.code()); // Ambiguity errors are often caused as fallout from earlier errors. // We ignore them if this `infcx` is tainted in some cases below. @@ -2033,13 +2124,11 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { } } - if let ObligationCauseCode::ItemObligation(def_id) = *obligation.cause.code() { + if let ObligationCauseCode::ItemObligation(def_id) | ObligationCauseCode::ExprItemObligation(def_id, ..) = *obligation.cause.code() { self.suggest_fully_qualified_path(&mut err, def_id, span, trait_ref.def_id()); - } else if let ( - Ok(ref snippet), - &ObligationCauseCode::BindingObligation(def_id, _), - ) = - (self.tcx.sess.source_map().span_to_snippet(span), obligation.cause.code()) + } else if let Ok(snippet) = &self.tcx.sess.source_map().span_to_snippet(span) + && let ObligationCauseCode::BindingObligation(def_id, _) | ObligationCauseCode::ExprBindingObligation(def_id, ..) + = *obligation.cause.code() { let generics = self.tcx.generics_of(def_id); if generics.params.iter().any(|p| p.name != kw::SelfUpper) @@ -2119,12 +2208,12 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { && let [ .., trait_path_segment @ hir::PathSegment { - res: Some(rustc_hir::def::Res::Def(rustc_hir::def::DefKind::Trait, trait_id)), + res: rustc_hir::def::Res::Def(rustc_hir::def::DefKind::Trait, trait_id), .. }, hir::PathSegment { ident: assoc_item_name, - res: Some(rustc_hir::def::Res::Def(_, item_id)), + res: rustc_hir::def::Res::Def(_, item_id), .. } ] = path.segments @@ -2462,15 +2551,10 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { err: &mut Diagnostic, obligation: &PredicateObligation<'tcx>, ) { - let ( - ty::PredicateKind::Trait(pred), - &ObligationCauseCode::BindingObligation(item_def_id, span), - ) = ( - obligation.predicate.kind().skip_binder(), - obligation.cause.code().peel_derives(), - ) else { - return; - }; + let ty::PredicateKind::Trait(pred) = obligation.predicate.kind().skip_binder() else { return; }; + let (ObligationCauseCode::BindingObligation(item_def_id, span) + | ObligationCauseCode::ExprBindingObligation(item_def_id, span, ..)) + = *obligation.cause.code().peel_derives() else { return; }; debug!(?pred, ?item_def_id, ?span); let (Some(node), true) = ( |