| //! Error Reporting Code for the inference engine |
| //! |
| //! Because of the way inference, and in particular region inference, |
| //! works, it often happens that errors are not detected until far after |
| //! the relevant line of code has been type-checked. Therefore, there is |
| //! an elaborate system to track why a particular constraint in the |
| //! inference graph arose so that we can explain to the user what gave |
| //! rise to a particular error. |
| //! |
| //! The system is based around a set of "origin" types. An "origin" is the |
| //! reason that a constraint or inference variable arose. There are |
| //! different "origin" enums for different kinds of constraints/variables |
| //! (e.g., `TypeOrigin`, `RegionVariableOrigin`). An origin always has |
| //! a span, but also more information so that we can generate a meaningful |
| //! error message. |
| //! |
| //! Having a catalog of all the different reasons an error can arise is |
| //! also useful for other reasons, like cross-referencing FAQs etc, though |
| //! we are not really taking advantage of this yet. |
| //! |
| //! # Region Inference |
| //! |
| //! Region inference is particularly tricky because it always succeeds "in |
| //! the moment" and simply registers a constraint. Then, at the end, we |
| //! can compute the full graph and report errors, so we need to be able to |
| //! store and later report what gave rise to the conflicting constraints. |
| //! |
| //! # Subtype Trace |
| //! |
| //! Determining whether `T1 <: T2` often involves a number of subtypes and |
| //! subconstraints along the way. A "TypeTrace" is an extended version |
| //! of an origin that traces the types and other values that were being |
| //! compared. It is not necessarily comprehensive (in fact, at the time of |
| //! this writing it only tracks the root values being compared) but I'd |
| //! like to extend it to include significant "waypoints". For example, if |
| //! you are comparing `(T1, T2) <: (T3, T4)`, and the problem is that `T2 |
| //! <: T4` fails, I'd like the trace to include enough information to say |
| //! "in the 2nd element of the tuple". Similarly, failures when comparing |
| //! arguments or return types in fn types should be able to cite the |
| //! specific position, etc. |
| //! |
| //! # Reality vs plan |
| //! |
| //! Of course, there is still a LOT of code in typeck that has yet to be |
| //! ported to this system, and which relies on string concatenation at the |
| //! time of error detection. |
| |
| use super::lexical_region_resolve::RegionResolutionError; |
| use super::region_constraints::GenericKind; |
| use super::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TypeTrace, ValuePairs}; |
| |
| use crate::errors::{self, ObligationCauseFailureCode, TypeErrorAdditionalDiags}; |
| use crate::infer; |
| use crate::infer::error_reporting::nice_region_error::find_anon_type::find_anon_type; |
| use crate::infer::ExpectedFound; |
| use crate::traits::{ |
| IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode, |
| PredicateObligation, |
| }; |
| |
| use rustc_data_structures::fx::{FxIndexMap, FxIndexSet}; |
| use rustc_errors::{ |
| codes::*, pluralize, struct_span_code_err, Applicability, Diag, DiagCtxt, DiagStyledString, |
| ErrorGuaranteed, IntoDiagArg, StringPart, |
| }; |
| use rustc_hir as hir; |
| use rustc_hir::def::DefKind; |
| use rustc_hir::def_id::{DefId, LocalDefId}; |
| use rustc_hir::intravisit::Visitor; |
| use rustc_hir::lang_items::LangItem; |
| use rustc_macros::extension; |
| use rustc_middle::dep_graph::DepContext; |
| use rustc_middle::ty::print::{with_forced_trimmed_paths, PrintError}; |
| use rustc_middle::ty::relate::{self, RelateResult, TypeRelation}; |
| use rustc_middle::ty::ToPredicate; |
| use rustc_middle::ty::{ |
| self, error::TypeError, IsSuggestable, List, Region, Ty, TyCtxt, TypeFoldable, |
| TypeSuperVisitable, TypeVisitable, TypeVisitableExt, |
| }; |
| use rustc_span::{sym, symbol::kw, BytePos, DesugaringKind, Pos, Span}; |
| use rustc_target::spec::abi; |
| use std::borrow::Cow; |
| use std::ops::{ControlFlow, Deref}; |
| use std::path::PathBuf; |
| use std::{cmp, fmt, iter}; |
| |
| mod note; |
| mod note_and_explain; |
| mod suggest; |
| |
| pub(crate) mod need_type_info; |
| pub mod sub_relations; |
| pub use need_type_info::TypeAnnotationNeeded; |
| |
| pub mod nice_region_error; |
| |
| /// Makes a valid string literal from a string by escaping special characters (" and \), |
| /// unless they are already escaped. |
| fn escape_literal(s: &str) -> String { |
| let mut escaped = String::with_capacity(s.len()); |
| let mut chrs = s.chars().peekable(); |
| while let Some(first) = chrs.next() { |
| match (first, chrs.peek()) { |
| ('\\', Some(&delim @ '"') | Some(&delim @ '\'')) => { |
| escaped.push('\\'); |
| escaped.push(delim); |
| chrs.next(); |
| } |
| ('"' | '\'', _) => { |
| escaped.push('\\'); |
| escaped.push(first) |
| } |
| (c, _) => escaped.push(c), |
| }; |
| } |
| escaped |
| } |
| |
| /// A helper for building type related errors. The `typeck_results` |
| /// field is only populated during an in-progress typeck. |
| /// Get an instance by calling `InferCtxt::err_ctxt` or `FnCtxt::err_ctxt`. |
| /// |
| /// You must only create this if you intend to actually emit an error (or |
| /// perhaps a warning, though preferably not.) It provides a lot of utility |
| /// methods which should not be used during the happy path. |
| pub struct TypeErrCtxt<'a, 'tcx> { |
| pub infcx: &'a InferCtxt<'tcx>, |
| pub sub_relations: std::cell::RefCell<sub_relations::SubRelations>, |
| |
| pub typeck_results: Option<std::cell::Ref<'a, ty::TypeckResults<'tcx>>>, |
| pub fallback_has_occurred: bool, |
| |
| pub normalize_fn_sig: Box<dyn Fn(ty::PolyFnSig<'tcx>) -> ty::PolyFnSig<'tcx> + 'a>, |
| |
| pub autoderef_steps: |
| Box<dyn Fn(Ty<'tcx>) -> Vec<(Ty<'tcx>, Vec<PredicateObligation<'tcx>>)> + 'a>, |
| } |
| |
| impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { |
| pub fn dcx(&self) -> &'tcx DiagCtxt { |
| self.infcx.tcx.dcx() |
| } |
| |
| /// This is just to avoid a potential footgun of accidentally |
| /// dropping `typeck_results` by calling `InferCtxt::err_ctxt` |
| #[deprecated(note = "you already have a `TypeErrCtxt`")] |
| #[allow(unused)] |
| pub fn err_ctxt(&self) -> ! { |
| bug!("called `err_ctxt` on `TypeErrCtxt`. Try removing the call"); |
| } |
| } |
| |
| impl<'tcx> Deref for TypeErrCtxt<'_, 'tcx> { |
| type Target = InferCtxt<'tcx>; |
| fn deref(&self) -> &InferCtxt<'tcx> { |
| self.infcx |
| } |
| } |
| |
| pub(super) fn note_and_explain_region<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| err: &mut Diag<'_>, |
| prefix: &str, |
| region: ty::Region<'tcx>, |
| suffix: &str, |
| alt_span: Option<Span>, |
| ) { |
| let (description, span) = match *region { |
| ty::ReEarlyParam(_) | ty::ReLateParam(_) | ty::RePlaceholder(_) | ty::ReStatic => { |
| msg_span_from_named_region(tcx, region, alt_span) |
| } |
| |
| ty::ReError(_) => return, |
| |
| ty::ReVar(_) | ty::ReBound(..) | ty::ReErased => { |
| bug!("unexpected region for note_and_explain_region: {:?}", region); |
| } |
| }; |
| |
| emit_msg_span(err, prefix, description, span, suffix); |
| } |
| |
| fn explain_free_region<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| err: &mut Diag<'_>, |
| prefix: &str, |
| region: ty::Region<'tcx>, |
| suffix: &str, |
| ) { |
| let (description, span) = msg_span_from_named_region(tcx, region, None); |
| |
| label_msg_span(err, prefix, description, span, suffix); |
| } |
| |
| fn msg_span_from_named_region<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| region: ty::Region<'tcx>, |
| alt_span: Option<Span>, |
| ) -> (String, Option<Span>) { |
| match *region { |
| ty::ReEarlyParam(ref br) => { |
| let scope = region.free_region_binding_scope(tcx).expect_local(); |
| let span = if let Some(param) = |
| tcx.hir().get_generics(scope).and_then(|generics| generics.get_named(br.name)) |
| { |
| param.span |
| } else { |
| tcx.def_span(scope) |
| }; |
| let text = if br.has_name() { |
| format!("the lifetime `{}` as defined here", br.name) |
| } else { |
| "the anonymous lifetime as defined here".to_string() |
| }; |
| (text, Some(span)) |
| } |
| ty::ReLateParam(ref fr) => { |
| if !fr.bound_region.is_named() |
| && let Some((ty, _)) = find_anon_type(tcx, region, &fr.bound_region) |
| { |
| ("the anonymous lifetime defined here".to_string(), Some(ty.span)) |
| } else { |
| let scope = region.free_region_binding_scope(tcx).expect_local(); |
| match fr.bound_region { |
| ty::BoundRegionKind::BrNamed(_, name) => { |
| let span = if let Some(param) = tcx |
| .hir() |
| .get_generics(scope) |
| .and_then(|generics| generics.get_named(name)) |
| { |
| param.span |
| } else { |
| tcx.def_span(scope) |
| }; |
| let text = if name == kw::UnderscoreLifetime { |
| "the anonymous lifetime as defined here".to_string() |
| } else { |
| format!("the lifetime `{name}` as defined here") |
| }; |
| (text, Some(span)) |
| } |
| ty::BrAnon => ( |
| "the anonymous lifetime as defined here".to_string(), |
| Some(tcx.def_span(scope)), |
| ), |
| _ => ( |
| format!("the lifetime `{region}` as defined here"), |
| Some(tcx.def_span(scope)), |
| ), |
| } |
| } |
| } |
| ty::ReStatic => ("the static lifetime".to_owned(), alt_span), |
| ty::RePlaceholder(ty::PlaceholderRegion { |
| bound: ty::BoundRegion { kind: ty::BoundRegionKind::BrNamed(def_id, name), .. }, |
| .. |
| }) => (format!("the lifetime `{name}` as defined here"), Some(tcx.def_span(def_id))), |
| ty::RePlaceholder(ty::PlaceholderRegion { |
| bound: ty::BoundRegion { kind: ty::BoundRegionKind::BrAnon, .. }, |
| .. |
| }) => ("an anonymous lifetime".to_owned(), None), |
| _ => bug!("{:?}", region), |
| } |
| } |
| |
| fn emit_msg_span( |
| err: &mut Diag<'_>, |
| prefix: &str, |
| description: String, |
| span: Option<Span>, |
| suffix: &str, |
| ) { |
| let message = format!("{prefix}{description}{suffix}"); |
| |
| if let Some(span) = span { |
| err.span_note(span, message); |
| } else { |
| err.note(message); |
| } |
| } |
| |
| fn label_msg_span( |
| err: &mut Diag<'_>, |
| prefix: &str, |
| description: String, |
| span: Option<Span>, |
| suffix: &str, |
| ) { |
| let message = format!("{prefix}{description}{suffix}"); |
| |
| if let Some(span) = span { |
| err.span_label(span, message); |
| } else { |
| err.note(message); |
| } |
| } |
| |
| #[instrument(level = "trace", skip(tcx))] |
| pub fn unexpected_hidden_region_diagnostic<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| span: Span, |
| hidden_ty: Ty<'tcx>, |
| hidden_region: ty::Region<'tcx>, |
| opaque_ty_key: ty::OpaqueTypeKey<'tcx>, |
| ) -> Diag<'tcx> { |
| let mut err = tcx.dcx().create_err(errors::OpaqueCapturesLifetime { |
| span, |
| opaque_ty: Ty::new_opaque(tcx, opaque_ty_key.def_id.to_def_id(), opaque_ty_key.args), |
| opaque_ty_span: tcx.def_span(opaque_ty_key.def_id), |
| }); |
| |
| // Explain the region we are capturing. |
| match *hidden_region { |
| ty::ReEarlyParam(_) | ty::ReLateParam(_) | ty::ReStatic => { |
| // Assuming regionck succeeded (*), we ought to always be |
| // capturing *some* region from the fn header, and hence it |
| // ought to be free. So under normal circumstances, we will go |
| // down this path which gives a decent human readable |
| // explanation. |
| // |
| // (*) if not, the `tainted_by_errors` field would be set to |
| // `Some(ErrorGuaranteed)` in any case, so we wouldn't be here at all. |
| explain_free_region( |
| tcx, |
| &mut err, |
| &format!("hidden type `{hidden_ty}` captures "), |
| hidden_region, |
| "", |
| ); |
| if let Some(reg_info) = tcx.is_suitable_region(hidden_region) { |
| let fn_returns = tcx.return_type_impl_or_dyn_traits(reg_info.def_id); |
| nice_region_error::suggest_new_region_bound( |
| tcx, |
| &mut err, |
| fn_returns, |
| hidden_region.to_string(), |
| None, |
| format!("captures `{hidden_region}`"), |
| None, |
| Some(reg_info.def_id), |
| ) |
| } |
| } |
| ty::RePlaceholder(_) => { |
| explain_free_region( |
| tcx, |
| &mut err, |
| &format!("hidden type `{}` captures ", hidden_ty), |
| hidden_region, |
| "", |
| ); |
| } |
| ty::ReError(_) => { |
| err.downgrade_to_delayed_bug(); |
| } |
| _ => { |
| // Ugh. This is a painful case: the hidden region is not one |
| // that we can easily summarize or explain. This can happen |
| // in a case like |
| // `tests/ui/multiple-lifetimes/ordinary-bounds-unsuited.rs`: |
| // |
| // ``` |
| // fn upper_bounds<'a, 'b>(a: Ordinary<'a>, b: Ordinary<'b>) -> impl Trait<'a, 'b> { |
| // if condition() { a } else { b } |
| // } |
| // ``` |
| // |
| // Here the captured lifetime is the intersection of `'a` and |
| // `'b`, which we can't quite express. |
| |
| // We can at least report a really cryptic error for now. |
| note_and_explain_region( |
| tcx, |
| &mut err, |
| &format!("hidden type `{hidden_ty}` captures "), |
| hidden_region, |
| "", |
| None, |
| ); |
| } |
| } |
| |
| err |
| } |
| |
| impl<'tcx> InferCtxt<'tcx> { |
| pub fn get_impl_future_output_ty(&self, ty: Ty<'tcx>) -> Option<Ty<'tcx>> { |
| let (def_id, args) = match *ty.kind() { |
| ty::Alias(_, ty::AliasTy { def_id, args, .. }) |
| if matches!(self.tcx.def_kind(def_id), DefKind::OpaqueTy) => |
| { |
| (def_id, args) |
| } |
| ty::Alias(_, ty::AliasTy { def_id, args, .. }) |
| if self.tcx.is_impl_trait_in_trait(def_id) => |
| { |
| (def_id, args) |
| } |
| _ => return None, |
| }; |
| |
| let future_trait = self.tcx.require_lang_item(LangItem::Future, None); |
| let item_def_id = self.tcx.associated_item_def_ids(future_trait)[0]; |
| |
| self.tcx |
| .explicit_item_super_predicates(def_id) |
| .iter_instantiated_copied(self.tcx, args) |
| .find_map(|(predicate, _)| { |
| predicate |
| .kind() |
| .map_bound(|kind| match kind { |
| ty::ClauseKind::Projection(projection_predicate) |
| if projection_predicate.projection_ty.def_id == item_def_id => |
| { |
| projection_predicate.term.ty() |
| } |
| _ => None, |
| }) |
| .no_bound_vars() |
| .flatten() |
| }) |
| } |
| } |
| |
| impl<'tcx> TypeErrCtxt<'_, 'tcx> { |
| pub fn report_region_errors( |
| &self, |
| generic_param_scope: LocalDefId, |
| errors: &[RegionResolutionError<'tcx>], |
| ) -> ErrorGuaranteed { |
| assert!(!errors.is_empty()); |
| |
| if let Some(guaranteed) = self.infcx.tainted_by_errors() { |
| return guaranteed; |
| } |
| |
| debug!("report_region_errors(): {} errors to start", errors.len()); |
| |
| // try to pre-process the errors, which will group some of them |
| // together into a `ProcessedErrors` group: |
| let errors = self.process_errors(errors); |
| |
| debug!("report_region_errors: {} errors after preprocessing", errors.len()); |
| |
| let mut guar = None; |
| for error in errors { |
| debug!("report_region_errors: error = {:?}", error); |
| |
| guar = Some(if let Some(guar) = self.try_report_nice_region_error(&error) { |
| guar |
| } else { |
| match error.clone() { |
| // These errors could indicate all manner of different |
| // problems with many different solutions. Rather |
| // than generate a "one size fits all" error, what we |
| // attempt to do is go through a number of specific |
| // scenarios and try to find the best way to present |
| // the error. If all of these fails, we fall back to a rather |
| // general bit of code that displays the error information |
| RegionResolutionError::ConcreteFailure(origin, sub, sup) => { |
| if sub.is_placeholder() || sup.is_placeholder() { |
| self.report_placeholder_failure(origin, sub, sup).emit() |
| } else { |
| self.report_concrete_failure(origin, sub, sup).emit() |
| } |
| } |
| |
| RegionResolutionError::GenericBoundFailure(origin, param_ty, sub) => self |
| .report_generic_bound_failure( |
| generic_param_scope, |
| origin.span(), |
| Some(origin), |
| param_ty, |
| sub, |
| ), |
| |
| RegionResolutionError::SubSupConflict( |
| _, |
| var_origin, |
| sub_origin, |
| sub_r, |
| sup_origin, |
| sup_r, |
| _, |
| ) => { |
| if sub_r.is_placeholder() { |
| self.report_placeholder_failure(sub_origin, sub_r, sup_r).emit() |
| } else if sup_r.is_placeholder() { |
| self.report_placeholder_failure(sup_origin, sub_r, sup_r).emit() |
| } else { |
| self.report_sub_sup_conflict( |
| var_origin, sub_origin, sub_r, sup_origin, sup_r, |
| ) |
| } |
| } |
| |
| RegionResolutionError::UpperBoundUniverseConflict( |
| _, |
| _, |
| _, |
| sup_origin, |
| sup_r, |
| ) => { |
| assert!(sup_r.is_placeholder()); |
| |
| // Make a dummy value for the "sub region" -- |
| // this is the initial value of the |
| // placeholder. In practice, we expect more |
| // tailored errors that don't really use this |
| // value. |
| let sub_r = self.tcx.lifetimes.re_erased; |
| |
| self.report_placeholder_failure(sup_origin, sub_r, sup_r).emit() |
| } |
| |
| RegionResolutionError::CannotNormalize(clause, origin) => { |
| let clause: ty::Clause<'tcx> = |
| clause.map_bound(ty::ClauseKind::TypeOutlives).to_predicate(self.tcx); |
| self.tcx |
| .dcx() |
| .struct_span_err(origin.span(), format!("cannot normalize `{clause}`")) |
| .emit() |
| } |
| } |
| }) |
| } |
| |
| guar.unwrap() |
| } |
| |
| // This method goes through all the errors and try to group certain types |
| // of error together, for the purpose of suggesting explicit lifetime |
| // parameters to the user. This is done so that we can have a more |
| // complete view of what lifetimes should be the same. |
| // If the return value is an empty vector, it means that processing |
| // failed (so the return value of this method should not be used). |
| // |
| // The method also attempts to weed out messages that seem like |
| // duplicates that will be unhelpful to the end-user. But |
| // obviously it never weeds out ALL errors. |
| fn process_errors( |
| &self, |
| errors: &[RegionResolutionError<'tcx>], |
| ) -> Vec<RegionResolutionError<'tcx>> { |
| debug!("process_errors()"); |
| |
| // We want to avoid reporting generic-bound failures if we can |
| // avoid it: these have a very high rate of being unhelpful in |
| // practice. This is because they are basically secondary |
| // checks that test the state of the region graph after the |
| // rest of inference is done, and the other kinds of errors |
| // indicate that the region constraint graph is internally |
| // inconsistent, so these test results are likely to be |
| // meaningless. |
| // |
| // Therefore, we filter them out of the list unless they are |
| // the only thing in the list. |
| |
| let is_bound_failure = |e: &RegionResolutionError<'tcx>| match *e { |
| RegionResolutionError::GenericBoundFailure(..) => true, |
| RegionResolutionError::ConcreteFailure(..) |
| | RegionResolutionError::SubSupConflict(..) |
| | RegionResolutionError::UpperBoundUniverseConflict(..) |
| | RegionResolutionError::CannotNormalize(..) => false, |
| }; |
| |
| let mut errors = if errors.iter().all(|e| is_bound_failure(e)) { |
| errors.to_owned() |
| } else { |
| errors.iter().filter(|&e| !is_bound_failure(e)).cloned().collect() |
| }; |
| |
| // sort the errors by span, for better error message stability. |
| errors.sort_by_key(|u| match *u { |
| RegionResolutionError::ConcreteFailure(ref sro, _, _) => sro.span(), |
| RegionResolutionError::GenericBoundFailure(ref sro, _, _) => sro.span(), |
| RegionResolutionError::SubSupConflict(_, ref rvo, _, _, _, _, _) => rvo.span(), |
| RegionResolutionError::UpperBoundUniverseConflict(_, ref rvo, _, _, _) => rvo.span(), |
| RegionResolutionError::CannotNormalize(_, ref sro) => sro.span(), |
| }); |
| errors |
| } |
| |
| /// Adds a note if the types come from similarly named crates |
| fn check_and_note_conflicting_crates(&self, err: &mut Diag<'_>, terr: TypeError<'tcx>) { |
| use hir::def_id::CrateNum; |
| use rustc_hir::definitions::DisambiguatedDefPathData; |
| use ty::print::Printer; |
| use ty::GenericArg; |
| |
| struct AbsolutePathPrinter<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| segments: Vec<String>, |
| } |
| |
| impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> { |
| fn tcx<'a>(&'a self) -> TyCtxt<'tcx> { |
| self.tcx |
| } |
| |
| fn print_region(&mut self, _region: ty::Region<'_>) -> Result<(), PrintError> { |
| Err(fmt::Error) |
| } |
| |
| fn print_type(&mut self, _ty: Ty<'tcx>) -> Result<(), PrintError> { |
| Err(fmt::Error) |
| } |
| |
| fn print_dyn_existential( |
| &mut self, |
| _predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, |
| ) -> Result<(), PrintError> { |
| Err(fmt::Error) |
| } |
| |
| fn print_const(&mut self, _ct: ty::Const<'tcx>) -> Result<(), PrintError> { |
| Err(fmt::Error) |
| } |
| |
| fn path_crate(&mut self, cnum: CrateNum) -> Result<(), PrintError> { |
| self.segments = vec![self.tcx.crate_name(cnum).to_string()]; |
| Ok(()) |
| } |
| fn path_qualified( |
| &mut self, |
| _self_ty: Ty<'tcx>, |
| _trait_ref: Option<ty::TraitRef<'tcx>>, |
| ) -> Result<(), PrintError> { |
| Err(fmt::Error) |
| } |
| |
| fn path_append_impl( |
| &mut self, |
| _print_prefix: impl FnOnce(&mut Self) -> Result<(), PrintError>, |
| _disambiguated_data: &DisambiguatedDefPathData, |
| _self_ty: Ty<'tcx>, |
| _trait_ref: Option<ty::TraitRef<'tcx>>, |
| ) -> Result<(), PrintError> { |
| Err(fmt::Error) |
| } |
| fn path_append( |
| &mut self, |
| print_prefix: impl FnOnce(&mut Self) -> Result<(), PrintError>, |
| disambiguated_data: &DisambiguatedDefPathData, |
| ) -> Result<(), PrintError> { |
| print_prefix(self)?; |
| self.segments.push(disambiguated_data.to_string()); |
| Ok(()) |
| } |
| fn path_generic_args( |
| &mut self, |
| print_prefix: impl FnOnce(&mut Self) -> Result<(), PrintError>, |
| _args: &[GenericArg<'tcx>], |
| ) -> Result<(), PrintError> { |
| print_prefix(self) |
| } |
| } |
| |
| let report_path_match = |err: &mut Diag<'_>, did1: DefId, did2: DefId| { |
| // Only report definitions from different crates. If both definitions |
| // are from a local module we could have false positives, e.g. |
| // let _ = [{struct Foo; Foo}, {struct Foo; Foo}]; |
| if did1.krate != did2.krate { |
| let abs_path = |def_id| { |
| let mut printer = AbsolutePathPrinter { tcx: self.tcx, segments: vec![] }; |
| printer.print_def_path(def_id, &[]).map(|_| printer.segments) |
| }; |
| |
| // We compare strings because DefPath can be different |
| // for imported and non-imported crates |
| let same_path = || -> Result<_, PrintError> { |
| Ok(self.tcx.def_path_str(did1) == self.tcx.def_path_str(did2) |
| || abs_path(did1)? == abs_path(did2)?) |
| }; |
| if same_path().unwrap_or(false) { |
| let crate_name = self.tcx.crate_name(did1.krate); |
| let msg = if did1.is_local() || did2.is_local() { |
| format!( |
| "the crate `{crate_name}` is compiled multiple times, possibly with different configurations" |
| ) |
| } else { |
| format!( |
| "perhaps two different versions of crate `{crate_name}` are being used?" |
| ) |
| }; |
| err.note(msg); |
| } |
| } |
| }; |
| match terr { |
| TypeError::Sorts(ref exp_found) => { |
| // if they are both "path types", there's a chance of ambiguity |
| // due to different versions of the same crate |
| if let (&ty::Adt(exp_adt, _), &ty::Adt(found_adt, _)) = |
| (exp_found.expected.kind(), exp_found.found.kind()) |
| { |
| report_path_match(err, exp_adt.did(), found_adt.did()); |
| } |
| } |
| TypeError::Traits(ref exp_found) => { |
| report_path_match(err, exp_found.expected, exp_found.found); |
| } |
| _ => (), // FIXME(#22750) handle traits and stuff |
| } |
| } |
| |
| fn note_error_origin( |
| &self, |
| err: &mut Diag<'_>, |
| cause: &ObligationCause<'tcx>, |
| exp_found: Option<ty::error::ExpectedFound<Ty<'tcx>>>, |
| terr: TypeError<'tcx>, |
| ) { |
| match *cause.code() { |
| ObligationCauseCode::Pattern { origin_expr: true, span: Some(span), root_ty } => { |
| let ty = self.resolve_vars_if_possible(root_ty); |
| if !matches!(ty.kind(), ty::Infer(ty::InferTy::TyVar(_) | ty::InferTy::FreshTy(_))) |
| { |
| // don't show type `_` |
| if span.desugaring_kind() == Some(DesugaringKind::ForLoop) |
| && let ty::Adt(def, args) = ty.kind() |
| && Some(def.did()) == self.tcx.get_diagnostic_item(sym::Option) |
| { |
| err.span_label( |
| span, |
| format!("this is an iterator with items of type `{}`", args.type_at(0)), |
| ); |
| } else { |
| err.span_label(span, format!("this expression has type `{ty}`")); |
| } |
| } |
| if let Some(ty::error::ExpectedFound { found, .. }) = exp_found |
| && ty.is_box() |
| && ty.boxed_ty() == found |
| && let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) |
| { |
| err.span_suggestion( |
| span, |
| "consider dereferencing the boxed value", |
| format!("*{snippet}"), |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| ObligationCauseCode::Pattern { origin_expr: false, span: Some(span), .. } => { |
| err.span_label(span, "expected due to this"); |
| } |
| ObligationCauseCode::BlockTailExpression( |
| _, |
| hir::MatchSource::TryDesugar(scrut_hir_id), |
| ) => { |
| if let Some(ty::error::ExpectedFound { expected, .. }) = exp_found { |
| let scrut_expr = self.tcx.hir().expect_expr(scrut_hir_id); |
| let scrut_ty = if let hir::ExprKind::Call(_, args) = &scrut_expr.kind { |
| let arg_expr = args.first().expect("try desugaring call w/out arg"); |
| self.typeck_results |
| .as_ref() |
| .and_then(|typeck_results| typeck_results.expr_ty_opt(arg_expr)) |
| } else { |
| bug!("try desugaring w/out call expr as scrutinee"); |
| }; |
| |
| match scrut_ty { |
| Some(ty) if expected == ty => { |
| let source_map = self.tcx.sess.source_map(); |
| err.span_suggestion( |
| source_map.end_point(cause.span()), |
| "try removing this `?`", |
| "", |
| Applicability::MachineApplicable, |
| ); |
| } |
| _ => {} |
| } |
| } |
| } |
| ObligationCauseCode::MatchExpressionArm(box MatchExpressionArmCause { |
| arm_block_id, |
| arm_span, |
| arm_ty, |
| prior_arm_block_id, |
| prior_arm_span, |
| prior_arm_ty, |
| source, |
| ref prior_non_diverging_arms, |
| scrut_span, |
| .. |
| }) => match source { |
| hir::MatchSource::TryDesugar(scrut_hir_id) => { |
| if let Some(ty::error::ExpectedFound { expected, .. }) = exp_found { |
| let scrut_expr = self.tcx.hir().expect_expr(scrut_hir_id); |
| let scrut_ty = if let hir::ExprKind::Call(_, args) = &scrut_expr.kind { |
| let arg_expr = args.first().expect("try desugaring call w/out arg"); |
| self.typeck_results |
| .as_ref() |
| .and_then(|typeck_results| typeck_results.expr_ty_opt(arg_expr)) |
| } else { |
| bug!("try desugaring w/out call expr as scrutinee"); |
| }; |
| |
| match scrut_ty { |
| Some(ty) if expected == ty => { |
| let source_map = self.tcx.sess.source_map(); |
| err.span_suggestion( |
| source_map.end_point(cause.span()), |
| "try removing this `?`", |
| "", |
| Applicability::MachineApplicable, |
| ); |
| } |
| _ => {} |
| } |
| } |
| } |
| _ => { |
| // `prior_arm_ty` can be `!`, `expected` will have better info when present. |
| let t = self.resolve_vars_if_possible(match exp_found { |
| Some(ty::error::ExpectedFound { expected, .. }) => expected, |
| _ => prior_arm_ty, |
| }); |
| let source_map = self.tcx.sess.source_map(); |
| let mut any_multiline_arm = source_map.is_multiline(arm_span); |
| if prior_non_diverging_arms.len() <= 4 { |
| for sp in prior_non_diverging_arms { |
| any_multiline_arm |= source_map.is_multiline(*sp); |
| err.span_label(*sp, format!("this is found to be of type `{t}`")); |
| } |
| } else if let Some(sp) = prior_non_diverging_arms.last() { |
| any_multiline_arm |= source_map.is_multiline(*sp); |
| err.span_label( |
| *sp, |
| format!("this and all prior arms are found to be of type `{t}`"), |
| ); |
| } |
| let outer = if any_multiline_arm || !source_map.is_multiline(cause.span) { |
| // Cover just `match` and the scrutinee expression, not |
| // the entire match body, to reduce diagram noise. |
| cause.span.shrink_to_lo().to(scrut_span) |
| } else { |
| cause.span |
| }; |
| let msg = "`match` arms have incompatible types"; |
| err.span_label(outer, msg); |
| if let Some(subdiag) = self.suggest_remove_semi_or_return_binding( |
| prior_arm_block_id, |
| prior_arm_ty, |
| prior_arm_span, |
| arm_block_id, |
| arm_ty, |
| arm_span, |
| ) { |
| err.subdiagnostic(self.dcx(), subdiag); |
| } |
| } |
| }, |
| ObligationCauseCode::IfExpression(box IfExpressionCause { |
| then_id, |
| else_id, |
| then_ty, |
| else_ty, |
| outer_span, |
| .. |
| }) => { |
| let then_span = self.find_block_span_from_hir_id(then_id); |
| let else_span = self.find_block_span_from_hir_id(else_id); |
| err.span_label(then_span, "expected because of this"); |
| if let Some(sp) = outer_span { |
| err.span_label(sp, "`if` and `else` have incompatible types"); |
| } |
| if let Some(subdiag) = self.suggest_remove_semi_or_return_binding( |
| Some(then_id), |
| then_ty, |
| then_span, |
| Some(else_id), |
| else_ty, |
| else_span, |
| ) { |
| err.subdiagnostic(self.dcx(), subdiag); |
| } |
| } |
| ObligationCauseCode::LetElse => { |
| err.help("try adding a diverging expression, such as `return` or `panic!(..)`"); |
| err.help("...or use `match` instead of `let...else`"); |
| } |
| _ => { |
| if let ObligationCauseCode::BindingObligation(_, span) |
| | ObligationCauseCode::ExprBindingObligation(_, span, ..) = |
| cause.code().peel_derives() |
| && let TypeError::RegionsPlaceholderMismatch = terr |
| { |
| err.span_note(*span, "the lifetime requirement is introduced here"); |
| } |
| } |
| } |
| } |
| |
| /// Given that `other_ty` is the same as a type argument for `name` in `sub`, populate `value` |
| /// highlighting `name` and every type argument that isn't at `pos` (which is `other_ty`), and |
| /// populate `other_value` with `other_ty`. |
| /// |
| /// ```text |
| /// Foo<Bar<Qux>> |
| /// ^^^^--------^ this is highlighted |
| /// | | |
| /// | this type argument is exactly the same as the other type, not highlighted |
| /// this is highlighted |
| /// Bar<Qux> |
| /// -------- this type is the same as a type argument in the other type, not highlighted |
| /// ``` |
| fn highlight_outer( |
| &self, |
| value: &mut DiagStyledString, |
| other_value: &mut DiagStyledString, |
| name: String, |
| sub: ty::GenericArgsRef<'tcx>, |
| pos: usize, |
| other_ty: Ty<'tcx>, |
| ) { |
| // `value` and `other_value` hold two incomplete type representation for display. |
| // `name` is the path of both types being compared. `sub` |
| value.push_highlighted(name); |
| let len = sub.len(); |
| if len > 0 { |
| value.push_highlighted("<"); |
| } |
| |
| // Output the lifetimes for the first type |
| let lifetimes = sub |
| .regions() |
| .map(|lifetime| { |
| let s = lifetime.to_string(); |
| if s.is_empty() { "'_".to_string() } else { s } |
| }) |
| .collect::<Vec<_>>() |
| .join(", "); |
| if !lifetimes.is_empty() { |
| if sub.regions().count() < len { |
| value.push_normal(lifetimes + ", "); |
| } else { |
| value.push_normal(lifetimes); |
| } |
| } |
| |
| // Highlight all the type arguments that aren't at `pos` and compare the type argument at |
| // `pos` and `other_ty`. |
| for (i, type_arg) in sub.types().enumerate() { |
| if i == pos { |
| let values = self.cmp(type_arg, other_ty); |
| value.0.extend((values.0).0); |
| other_value.0.extend((values.1).0); |
| } else { |
| value.push_highlighted(type_arg.to_string()); |
| } |
| |
| if len > 0 && i != len - 1 { |
| value.push_normal(", "); |
| } |
| } |
| if len > 0 { |
| value.push_highlighted(">"); |
| } |
| } |
| |
| /// If `other_ty` is the same as a type argument present in `sub`, highlight `path` in `t1_out`, |
| /// as that is the difference to the other type. |
| /// |
| /// For the following code: |
| /// |
| /// ```ignore (illustrative) |
| /// let x: Foo<Bar<Qux>> = foo::<Bar<Qux>>(); |
| /// ``` |
| /// |
| /// The type error output will behave in the following way: |
| /// |
| /// ```text |
| /// Foo<Bar<Qux>> |
| /// ^^^^--------^ this is highlighted |
| /// | | |
| /// | this type argument is exactly the same as the other type, not highlighted |
| /// this is highlighted |
| /// Bar<Qux> |
| /// -------- this type is the same as a type argument in the other type, not highlighted |
| /// ``` |
| fn cmp_type_arg( |
| &self, |
| t1_out: &mut DiagStyledString, |
| t2_out: &mut DiagStyledString, |
| path: String, |
| sub: &'tcx [ty::GenericArg<'tcx>], |
| other_path: String, |
| other_ty: Ty<'tcx>, |
| ) -> Option<()> { |
| // FIXME/HACK: Go back to `GenericArgsRef` to use its inherent methods, |
| // ideally that shouldn't be necessary. |
| let sub = self.tcx.mk_args(sub); |
| for (i, ta) in sub.types().enumerate() { |
| if ta == other_ty { |
| self.highlight_outer(t1_out, t2_out, path, sub, i, other_ty); |
| return Some(()); |
| } |
| if let ty::Adt(def, _) = ta.kind() { |
| let path_ = self.tcx.def_path_str(def.did()); |
| if path_ == other_path { |
| self.highlight_outer(t1_out, t2_out, path, sub, i, other_ty); |
| return Some(()); |
| } |
| } |
| } |
| None |
| } |
| |
| /// Adds a `,` to the type representation only if it is appropriate. |
| fn push_comma( |
| &self, |
| value: &mut DiagStyledString, |
| other_value: &mut DiagStyledString, |
| len: usize, |
| pos: usize, |
| ) { |
| if len > 0 && pos != len - 1 { |
| value.push_normal(", "); |
| other_value.push_normal(", "); |
| } |
| } |
| |
| /// Given two `fn` signatures highlight only sub-parts that are different. |
| fn cmp_fn_sig( |
| &self, |
| sig1: &ty::PolyFnSig<'tcx>, |
| sig2: &ty::PolyFnSig<'tcx>, |
| ) -> (DiagStyledString, DiagStyledString) { |
| let sig1 = &(self.normalize_fn_sig)(*sig1); |
| let sig2 = &(self.normalize_fn_sig)(*sig2); |
| |
| let get_lifetimes = |sig| { |
| use rustc_hir::def::Namespace; |
| let (sig, reg) = ty::print::FmtPrinter::new(self.tcx, Namespace::TypeNS) |
| .name_all_regions(sig) |
| .unwrap(); |
| let lts: Vec<String> = |
| reg.into_items().map(|(_, kind)| kind.to_string()).into_sorted_stable_ord(); |
| (if lts.is_empty() { String::new() } else { format!("for<{}> ", lts.join(", ")) }, sig) |
| }; |
| |
| let (lt1, sig1) = get_lifetimes(sig1); |
| let (lt2, sig2) = get_lifetimes(sig2); |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| let mut values = |
| (DiagStyledString::normal("".to_string()), DiagStyledString::normal("".to_string())); |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| // ^^^^^^ |
| values.0.push(sig1.unsafety.prefix_str(), sig1.unsafety != sig2.unsafety); |
| values.1.push(sig2.unsafety.prefix_str(), sig1.unsafety != sig2.unsafety); |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| // ^^^^^^^^^^ |
| if sig1.abi != abi::Abi::Rust { |
| values.0.push(format!("extern {} ", sig1.abi), sig1.abi != sig2.abi); |
| } |
| if sig2.abi != abi::Abi::Rust { |
| values.1.push(format!("extern {} ", sig2.abi), sig1.abi != sig2.abi); |
| } |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| // ^^^^^^^^ |
| let lifetime_diff = lt1 != lt2; |
| values.0.push(lt1, lifetime_diff); |
| values.1.push(lt2, lifetime_diff); |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| // ^^^ |
| values.0.push_normal("fn("); |
| values.1.push_normal("fn("); |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| // ^^^^^ |
| let len1 = sig1.inputs().len(); |
| let len2 = sig2.inputs().len(); |
| if len1 == len2 { |
| for (i, (l, r)) in iter::zip(sig1.inputs(), sig2.inputs()).enumerate() { |
| let (x1, x2) = self.cmp(*l, *r); |
| (values.0).0.extend(x1.0); |
| (values.1).0.extend(x2.0); |
| self.push_comma(&mut values.0, &mut values.1, len1, i); |
| } |
| } else { |
| for (i, l) in sig1.inputs().iter().enumerate() { |
| values.0.push_highlighted(l.to_string()); |
| if i != len1 - 1 { |
| values.0.push_highlighted(", "); |
| } |
| } |
| for (i, r) in sig2.inputs().iter().enumerate() { |
| values.1.push_highlighted(r.to_string()); |
| if i != len2 - 1 { |
| values.1.push_highlighted(", "); |
| } |
| } |
| } |
| |
| if sig1.c_variadic { |
| if len1 > 0 { |
| values.0.push_normal(", "); |
| } |
| values.0.push("...", !sig2.c_variadic); |
| } |
| if sig2.c_variadic { |
| if len2 > 0 { |
| values.1.push_normal(", "); |
| } |
| values.1.push("...", !sig1.c_variadic); |
| } |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| // ^ |
| values.0.push_normal(")"); |
| values.1.push_normal(")"); |
| |
| // unsafe extern "C" for<'a> fn(&'a T) -> &'a T |
| // ^^^^^^^^ |
| let output1 = sig1.output(); |
| let output2 = sig2.output(); |
| let (x1, x2) = self.cmp(output1, output2); |
| if !output1.is_unit() { |
| values.0.push_normal(" -> "); |
| (values.0).0.extend(x1.0); |
| } |
| if !output2.is_unit() { |
| values.1.push_normal(" -> "); |
| (values.1).0.extend(x2.0); |
| } |
| values |
| } |
| |
| /// Compares two given types, eliding parts that are the same between them and highlighting |
| /// relevant differences, and return two representation of those types for highlighted printing. |
| pub fn cmp(&self, t1: Ty<'tcx>, t2: Ty<'tcx>) -> (DiagStyledString, DiagStyledString) { |
| debug!("cmp(t1={}, t1.kind={:?}, t2={}, t2.kind={:?})", t1, t1.kind(), t2, t2.kind()); |
| |
| // helper functions |
| let recurse = |t1, t2, values: &mut (DiagStyledString, DiagStyledString)| { |
| let (x1, x2) = self.cmp(t1, t2); |
| (values.0).0.extend(x1.0); |
| (values.1).0.extend(x2.0); |
| }; |
| |
| fn fmt_region<'tcx>(region: ty::Region<'tcx>) -> String { |
| let mut r = region.to_string(); |
| if r == "'_" { |
| r.clear(); |
| } else { |
| r.push(' '); |
| } |
| format!("&{r}") |
| } |
| |
| fn push_ref<'tcx>( |
| region: ty::Region<'tcx>, |
| mutbl: hir::Mutability, |
| s: &mut DiagStyledString, |
| ) { |
| s.push_highlighted(fmt_region(region)); |
| s.push_highlighted(mutbl.prefix_str()); |
| } |
| |
| fn maybe_highlight<T: Eq + ToString>( |
| t1: T, |
| t2: T, |
| (buf1, buf2): &mut (DiagStyledString, DiagStyledString), |
| tcx: TyCtxt<'_>, |
| ) { |
| let highlight = t1 != t2; |
| let (t1, t2) = if highlight || tcx.sess.opts.verbose { |
| (t1.to_string(), t2.to_string()) |
| } else { |
| // The two types are the same, elide and don't highlight. |
| ("_".into(), "_".into()) |
| }; |
| buf1.push(t1, highlight); |
| buf2.push(t2, highlight); |
| } |
| |
| fn cmp_ty_refs<'tcx>( |
| r1: ty::Region<'tcx>, |
| mut1: hir::Mutability, |
| r2: ty::Region<'tcx>, |
| mut2: hir::Mutability, |
| ss: &mut (DiagStyledString, DiagStyledString), |
| ) { |
| let (r1, r2) = (fmt_region(r1), fmt_region(r2)); |
| if r1 != r2 { |
| ss.0.push_highlighted(r1); |
| ss.1.push_highlighted(r2); |
| } else { |
| ss.0.push_normal(r1); |
| ss.1.push_normal(r2); |
| } |
| |
| if mut1 != mut2 { |
| ss.0.push_highlighted(mut1.prefix_str()); |
| ss.1.push_highlighted(mut2.prefix_str()); |
| } else { |
| ss.0.push_normal(mut1.prefix_str()); |
| ss.1.push_normal(mut2.prefix_str()); |
| } |
| } |
| |
| // process starts here |
| match (t1.kind(), t2.kind()) { |
| (&ty::Adt(def1, sub1), &ty::Adt(def2, sub2)) => { |
| let did1 = def1.did(); |
| let did2 = def2.did(); |
| |
| let generics1 = self.tcx.generics_of(did1); |
| let generics2 = self.tcx.generics_of(did2); |
| |
| let non_default_after_default = generics1 |
| .check_concrete_type_after_default(self.tcx, sub1) |
| || generics2.check_concrete_type_after_default(self.tcx, sub2); |
| let sub_no_defaults_1 = if non_default_after_default { |
| generics1.own_args(sub1) |
| } else { |
| generics1.own_args_no_defaults(self.tcx, sub1) |
| }; |
| let sub_no_defaults_2 = if non_default_after_default { |
| generics2.own_args(sub2) |
| } else { |
| generics2.own_args_no_defaults(self.tcx, sub2) |
| }; |
| let mut values = (DiagStyledString::new(), DiagStyledString::new()); |
| let path1 = self.tcx.def_path_str(did1); |
| let path2 = self.tcx.def_path_str(did2); |
| if did1 == did2 { |
| // Easy case. Replace same types with `_` to shorten the output and highlight |
| // the differing ones. |
| // let x: Foo<Bar, Qux> = y::<Foo<Quz, Qux>>(); |
| // Foo<Bar, _> |
| // Foo<Quz, _> |
| // --- ^ type argument elided |
| // | |
| // highlighted in output |
| values.0.push_normal(path1); |
| values.1.push_normal(path2); |
| |
| // Avoid printing out default generic parameters that are common to both |
| // types. |
| let len1 = sub_no_defaults_1.len(); |
| let len2 = sub_no_defaults_2.len(); |
| let common_len = cmp::min(len1, len2); |
| let remainder1: Vec<_> = sub1.types().skip(common_len).collect(); |
| let remainder2: Vec<_> = sub2.types().skip(common_len).collect(); |
| let common_default_params = |
| iter::zip(remainder1.iter().rev(), remainder2.iter().rev()) |
| .filter(|(a, b)| a == b) |
| .count(); |
| let len = sub1.len() - common_default_params; |
| let consts_offset = len - sub1.consts().count(); |
| |
| // Only draw `<...>` if there are lifetime/type arguments. |
| if len > 0 { |
| values.0.push_normal("<"); |
| values.1.push_normal("<"); |
| } |
| |
| fn lifetime_display(lifetime: Region<'_>) -> String { |
| let s = lifetime.to_string(); |
| if s.is_empty() { "'_".to_string() } else { s } |
| } |
| // At one point we'd like to elide all lifetimes here, they are irrelevant for |
| // all diagnostics that use this output |
| // |
| // Foo<'x, '_, Bar> |
| // Foo<'y, '_, Qux> |
| // ^^ ^^ --- type arguments are not elided |
| // | | |
| // | elided as they were the same |
| // not elided, they were different, but irrelevant |
| // |
| // For bound lifetimes, keep the names of the lifetimes, |
| // even if they are the same so that it's clear what's happening |
| // if we have something like |
| // |
| // for<'r, 's> fn(Inv<'r>, Inv<'s>) |
| // for<'r> fn(Inv<'r>, Inv<'r>) |
| let lifetimes = sub1.regions().zip(sub2.regions()); |
| for (i, lifetimes) in lifetimes.enumerate() { |
| let l1 = lifetime_display(lifetimes.0); |
| let l2 = lifetime_display(lifetimes.1); |
| if lifetimes.0 != lifetimes.1 { |
| values.0.push_highlighted(l1); |
| values.1.push_highlighted(l2); |
| } else if lifetimes.0.is_bound() || self.tcx.sess.opts.verbose { |
| values.0.push_normal(l1); |
| values.1.push_normal(l2); |
| } else { |
| values.0.push_normal("'_"); |
| values.1.push_normal("'_"); |
| } |
| self.push_comma(&mut values.0, &mut values.1, len, i); |
| } |
| |
| // We're comparing two types with the same path, so we compare the type |
| // arguments for both. If they are the same, do not highlight and elide from the |
| // output. |
| // Foo<_, Bar> |
| // Foo<_, Qux> |
| // ^ elided type as this type argument was the same in both sides |
| let type_arguments = sub1.types().zip(sub2.types()); |
| let regions_len = sub1.regions().count(); |
| let num_display_types = consts_offset - regions_len; |
| for (i, (ta1, ta2)) in type_arguments.take(num_display_types).enumerate() { |
| let i = i + regions_len; |
| if ta1 == ta2 && !self.tcx.sess.opts.verbose { |
| values.0.push_normal("_"); |
| values.1.push_normal("_"); |
| } else { |
| recurse(ta1, ta2, &mut values); |
| } |
| self.push_comma(&mut values.0, &mut values.1, len, i); |
| } |
| |
| // Do the same for const arguments, if they are equal, do not highlight and |
| // elide them from the output. |
| let const_arguments = sub1.consts().zip(sub2.consts()); |
| for (i, (ca1, ca2)) in const_arguments.enumerate() { |
| let i = i + consts_offset; |
| maybe_highlight(ca1, ca2, &mut values, self.tcx); |
| self.push_comma(&mut values.0, &mut values.1, len, i); |
| } |
| |
| // Close the type argument bracket. |
| // Only draw `<...>` if there are lifetime/type arguments. |
| if len > 0 { |
| values.0.push_normal(">"); |
| values.1.push_normal(">"); |
| } |
| values |
| } else { |
| // Check for case: |
| // let x: Foo<Bar<Qux> = foo::<Bar<Qux>>(); |
| // Foo<Bar<Qux> |
| // ------- this type argument is exactly the same as the other type |
| // Bar<Qux> |
| if self |
| .cmp_type_arg( |
| &mut values.0, |
| &mut values.1, |
| path1.clone(), |
| sub_no_defaults_1, |
| path2.clone(), |
| t2, |
| ) |
| .is_some() |
| { |
| return values; |
| } |
| // Check for case: |
| // let x: Bar<Qux> = y:<Foo<Bar<Qux>>>(); |
| // Bar<Qux> |
| // Foo<Bar<Qux>> |
| // ------- this type argument is exactly the same as the other type |
| if self |
| .cmp_type_arg( |
| &mut values.1, |
| &mut values.0, |
| path2, |
| sub_no_defaults_2, |
| path1, |
| t1, |
| ) |
| .is_some() |
| { |
| return values; |
| } |
| |
| // We can't find anything in common, highlight relevant part of type path. |
| // let x: foo::bar::Baz<Qux> = y:<foo::bar::Bar<Zar>>(); |
| // foo::bar::Baz<Qux> |
| // foo::bar::Bar<Zar> |
| // -------- this part of the path is different |
| |
| let t1_str = t1.to_string(); |
| let t2_str = t2.to_string(); |
| let min_len = t1_str.len().min(t2_str.len()); |
| |
| const SEPARATOR: &str = "::"; |
| let separator_len = SEPARATOR.len(); |
| let split_idx: usize = |
| iter::zip(t1_str.split(SEPARATOR), t2_str.split(SEPARATOR)) |
| .take_while(|(mod1_str, mod2_str)| mod1_str == mod2_str) |
| .map(|(mod_str, _)| mod_str.len() + separator_len) |
| .sum(); |
| |
| debug!(?separator_len, ?split_idx, ?min_len, "cmp"); |
| |
| if split_idx >= min_len { |
| // paths are identical, highlight everything |
| ( |
| DiagStyledString::highlighted(t1_str), |
| DiagStyledString::highlighted(t2_str), |
| ) |
| } else { |
| let (common, uniq1) = t1_str.split_at(split_idx); |
| let (_, uniq2) = t2_str.split_at(split_idx); |
| debug!(?common, ?uniq1, ?uniq2, "cmp"); |
| |
| values.0.push_normal(common); |
| values.0.push_highlighted(uniq1); |
| values.1.push_normal(common); |
| values.1.push_highlighted(uniq2); |
| |
| values |
| } |
| } |
| } |
| |
| // When finding `&T != &T`, compare the references, then recurse into pointee type |
| (&ty::Ref(r1, ref_ty1, mutbl1), &ty::Ref(r2, ref_ty2, mutbl2)) => { |
| let mut values = (DiagStyledString::new(), DiagStyledString::new()); |
| cmp_ty_refs(r1, mutbl1, r2, mutbl2, &mut values); |
| recurse(ref_ty1, ref_ty2, &mut values); |
| values |
| } |
| // When finding T != &T, highlight the borrow |
| (&ty::Ref(r1, ref_ty1, mutbl1), _) => { |
| let mut values = (DiagStyledString::new(), DiagStyledString::new()); |
| push_ref(r1, mutbl1, &mut values.0); |
| recurse(ref_ty1, t2, &mut values); |
| values |
| } |
| (_, &ty::Ref(r2, ref_ty2, mutbl2)) => { |
| let mut values = (DiagStyledString::new(), DiagStyledString::new()); |
| push_ref(r2, mutbl2, &mut values.1); |
| recurse(t1, ref_ty2, &mut values); |
| values |
| } |
| |
| // When encountering tuples of the same size, highlight only the differing types |
| (&ty::Tuple(args1), &ty::Tuple(args2)) if args1.len() == args2.len() => { |
| let mut values = (DiagStyledString::normal("("), DiagStyledString::normal("(")); |
| let len = args1.len(); |
| for (i, (left, right)) in args1.iter().zip(args2).enumerate() { |
| recurse(left, right, &mut values); |
| self.push_comma(&mut values.0, &mut values.1, len, i); |
| } |
| if len == 1 { |
| // Keep the output for single element tuples as `(ty,)`. |
| values.0.push_normal(","); |
| values.1.push_normal(","); |
| } |
| values.0.push_normal(")"); |
| values.1.push_normal(")"); |
| values |
| } |
| |
| (ty::FnDef(did1, args1), ty::FnDef(did2, args2)) => { |
| let sig1 = self.tcx.fn_sig(*did1).instantiate(self.tcx, args1); |
| let sig2 = self.tcx.fn_sig(*did2).instantiate(self.tcx, args2); |
| let mut values = self.cmp_fn_sig(&sig1, &sig2); |
| let path1 = format!(" {{{}}}", self.tcx.def_path_str_with_args(*did1, args1)); |
| let path2 = format!(" {{{}}}", self.tcx.def_path_str_with_args(*did2, args2)); |
| let same_path = path1 == path2; |
| values.0.push(path1, !same_path); |
| values.1.push(path2, !same_path); |
| values |
| } |
| |
| (ty::FnDef(did1, args1), ty::FnPtr(sig2)) => { |
| let sig1 = self.tcx.fn_sig(*did1).instantiate(self.tcx, args1); |
| let mut values = self.cmp_fn_sig(&sig1, sig2); |
| values.0.push_highlighted(format!( |
| " {{{}}}", |
| self.tcx.def_path_str_with_args(*did1, args1) |
| )); |
| values |
| } |
| |
| (ty::FnPtr(sig1), ty::FnDef(did2, args2)) => { |
| let sig2 = self.tcx.fn_sig(*did2).instantiate(self.tcx, args2); |
| let mut values = self.cmp_fn_sig(sig1, &sig2); |
| values |
| .1 |
| .push_normal(format!(" {{{}}}", self.tcx.def_path_str_with_args(*did2, args2))); |
| values |
| } |
| |
| (ty::FnPtr(sig1), ty::FnPtr(sig2)) => self.cmp_fn_sig(sig1, sig2), |
| |
| _ => { |
| let mut strs = (DiagStyledString::new(), DiagStyledString::new()); |
| maybe_highlight(t1, t2, &mut strs, self.tcx); |
| strs |
| } |
| } |
| } |
| |
| /// Extend a type error with extra labels pointing at "non-trivial" types, like closures and |
| /// the return type of `async fn`s. |
| /// |
| /// `secondary_span` gives the caller the opportunity to expand `diag` with a `span_label`. |
| /// |
| /// `swap_secondary_and_primary` is used to make projection errors in particular nicer by using |
| /// the message in `secondary_span` as the primary label, and apply the message that would |
| /// otherwise be used for the primary label on the `secondary_span` `Span`. This applies on |
| /// E0271, like `tests/ui/issues/issue-39970.stderr`. |
| #[instrument( |
| level = "debug", |
| skip(self, diag, secondary_span, swap_secondary_and_primary, prefer_label) |
| )] |
| pub fn note_type_err( |
| &self, |
| diag: &mut Diag<'_>, |
| cause: &ObligationCause<'tcx>, |
| secondary_span: Option<(Span, Cow<'static, str>)>, |
| mut values: Option<ValuePairs<'tcx>>, |
| terr: TypeError<'tcx>, |
| swap_secondary_and_primary: bool, |
| prefer_label: bool, |
| ) { |
| let span = cause.span(); |
| |
| // For some types of errors, expected-found does not make |
| // sense, so just ignore the values we were given. |
| if let TypeError::CyclicTy(_) = terr { |
| values = None; |
| } |
| struct OpaqueTypesVisitor<'tcx> { |
| types: FxIndexMap<TyCategory, FxIndexSet<Span>>, |
| expected: FxIndexMap<TyCategory, FxIndexSet<Span>>, |
| found: FxIndexMap<TyCategory, FxIndexSet<Span>>, |
| ignore_span: Span, |
| tcx: TyCtxt<'tcx>, |
| } |
| |
| impl<'tcx> OpaqueTypesVisitor<'tcx> { |
| fn visit_expected_found( |
| tcx: TyCtxt<'tcx>, |
| expected: impl TypeVisitable<TyCtxt<'tcx>>, |
| found: impl TypeVisitable<TyCtxt<'tcx>>, |
| ignore_span: Span, |
| ) -> Self { |
| let mut types_visitor = OpaqueTypesVisitor { |
| types: Default::default(), |
| expected: Default::default(), |
| found: Default::default(), |
| ignore_span, |
| tcx, |
| }; |
| // The visitor puts all the relevant encountered types in `self.types`, but in |
| // here we want to visit two separate types with no relation to each other, so we |
| // move the results from `types` to `expected` or `found` as appropriate. |
| expected.visit_with(&mut types_visitor); |
| std::mem::swap(&mut types_visitor.expected, &mut types_visitor.types); |
| found.visit_with(&mut types_visitor); |
| std::mem::swap(&mut types_visitor.found, &mut types_visitor.types); |
| types_visitor |
| } |
| |
| fn report(&self, err: &mut Diag<'_>) { |
| self.add_labels_for_types(err, "expected", &self.expected); |
| self.add_labels_for_types(err, "found", &self.found); |
| } |
| |
| fn add_labels_for_types( |
| &self, |
| err: &mut Diag<'_>, |
| target: &str, |
| types: &FxIndexMap<TyCategory, FxIndexSet<Span>>, |
| ) { |
| for (kind, values) in types.iter() { |
| let count = values.len(); |
| for &sp in values { |
| err.span_label( |
| sp, |
| format!( |
| "{}{} {:#}{}", |
| if count == 1 { "the " } else { "one of the " }, |
| target, |
| kind, |
| pluralize!(count), |
| ), |
| ); |
| } |
| } |
| } |
| } |
| |
| impl<'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for OpaqueTypesVisitor<'tcx> { |
| fn visit_ty(&mut self, t: Ty<'tcx>) { |
| if let Some((kind, def_id)) = TyCategory::from_ty(self.tcx, t) { |
| let span = self.tcx.def_span(def_id); |
| // Avoid cluttering the output when the "found" and error span overlap: |
| // |
| // error[E0308]: mismatched types |
| // --> $DIR/issue-20862.rs:2:5 |
| // | |
| // LL | |y| x + y |
| // | ^^^^^^^^^ |
| // | | |
| // | the found closure |
| // | expected `()`, found closure |
| // | |
| // = note: expected unit type `()` |
| // found closure `{closure@$DIR/issue-20862.rs:2:5: 2:14 x:_}` |
| // |
| // Also ignore opaque `Future`s that come from async fns. |
| if !self.ignore_span.overlaps(span) |
| && !span.is_desugaring(DesugaringKind::Async) |
| { |
| self.types.entry(kind).or_default().insert(span); |
| } |
| } |
| t.super_visit_with(self) |
| } |
| } |
| |
| debug!("note_type_err(diag={:?})", diag); |
| enum Mismatch<'a> { |
| Variable(ty::error::ExpectedFound<Ty<'a>>), |
| Fixed(&'static str), |
| } |
| let (expected_found, exp_found, is_simple_error, values) = match values { |
| None => (None, Mismatch::Fixed("type"), false, None), |
| Some(values) => { |
| let values = self.resolve_vars_if_possible(values); |
| let (is_simple_error, exp_found) = match values { |
| ValuePairs::Terms(infer::ExpectedFound { expected, found }) => { |
| match (expected.unpack(), found.unpack()) { |
| (ty::TermKind::Ty(expected), ty::TermKind::Ty(found)) => { |
| let is_simple_err = expected.is_simple_text(self.tcx) |
| && found.is_simple_text(self.tcx); |
| OpaqueTypesVisitor::visit_expected_found( |
| self.tcx, expected, found, span, |
| ) |
| .report(diag); |
| |
| ( |
| is_simple_err, |
| Mismatch::Variable(infer::ExpectedFound { expected, found }), |
| ) |
| } |
| (ty::TermKind::Const(_), ty::TermKind::Const(_)) => { |
| (false, Mismatch::Fixed("constant")) |
| } |
| _ => (false, Mismatch::Fixed("type")), |
| } |
| } |
| ValuePairs::PolySigs(infer::ExpectedFound { expected, found }) => { |
| OpaqueTypesVisitor::visit_expected_found(self.tcx, expected, found, span) |
| .report(diag); |
| (false, Mismatch::Fixed("signature")) |
| } |
| ValuePairs::TraitRefs(_) => (false, Mismatch::Fixed("trait")), |
| ValuePairs::Aliases(infer::ExpectedFound { expected, .. }) => { |
| (false, Mismatch::Fixed(self.tcx.def_descr(expected.def_id))) |
| } |
| ValuePairs::Regions(_) => (false, Mismatch::Fixed("lifetime")), |
| ValuePairs::ExistentialTraitRef(_) => { |
| (false, Mismatch::Fixed("existential trait ref")) |
| } |
| ValuePairs::ExistentialProjection(_) => { |
| (false, Mismatch::Fixed("existential projection")) |
| } |
| }; |
| let Some(vals) = self.values_str(values) else { |
| // Derived error. Cancel the emitter. |
| // NOTE(eddyb) this was `.cancel()`, but `diag` |
| // is borrowed, so we can't fully defuse it. |
| diag.downgrade_to_delayed_bug(); |
| return; |
| }; |
| (Some(vals), exp_found, is_simple_error, Some(values)) |
| } |
| }; |
| |
| let mut label_or_note = |span: Span, msg: Cow<'static, str>| { |
| if (prefer_label && is_simple_error) || &[span] == diag.span.primary_spans() { |
| diag.span_label(span, msg); |
| } else { |
| diag.span_note(span, msg); |
| } |
| }; |
| if let Some((sp, msg)) = secondary_span { |
| if swap_secondary_and_primary { |
| let terr = if let Some(infer::ValuePairs::Terms(infer::ExpectedFound { |
| expected, |
| .. |
| })) = values |
| { |
| Cow::from(format!("expected this to be `{expected}`")) |
| } else { |
| terr.to_string(self.tcx) |
| }; |
| label_or_note(sp, terr); |
| label_or_note(span, msg); |
| } else { |
| label_or_note(span, terr.to_string(self.tcx)); |
| label_or_note(sp, msg); |
| } |
| } else { |
| if let Some(values) = values |
| && let Some((e, f)) = values.ty() |
| && let TypeError::ArgumentSorts(..) | TypeError::Sorts(_) = terr |
| { |
| let e = self.tcx.erase_regions(e); |
| let f = self.tcx.erase_regions(f); |
| let expected = with_forced_trimmed_paths!(e.sort_string(self.tcx)); |
| let found = with_forced_trimmed_paths!(f.sort_string(self.tcx)); |
| if expected == found { |
| label_or_note(span, terr.to_string(self.tcx)); |
| } else { |
| label_or_note(span, Cow::from(format!("expected {expected}, found {found}"))); |
| } |
| } else { |
| label_or_note(span, terr.to_string(self.tcx)); |
| } |
| } |
| |
| if let Some((expected, found, path)) = expected_found { |
| let (expected_label, found_label, exp_found) = match exp_found { |
| Mismatch::Variable(ef) => ( |
| ef.expected.prefix_string(self.tcx), |
| ef.found.prefix_string(self.tcx), |
| Some(ef), |
| ), |
| Mismatch::Fixed(s) => (s.into(), s.into(), None), |
| }; |
| |
| enum Similar<'tcx> { |
| Adts { expected: ty::AdtDef<'tcx>, found: ty::AdtDef<'tcx> }, |
| PrimitiveFound { expected: ty::AdtDef<'tcx>, found: Ty<'tcx> }, |
| PrimitiveExpected { expected: Ty<'tcx>, found: ty::AdtDef<'tcx> }, |
| } |
| |
| let similarity = |ExpectedFound { expected, found }: ExpectedFound<Ty<'tcx>>| { |
| if let ty::Adt(expected, _) = expected.kind() |
| && let Some(primitive) = found.primitive_symbol() |
| { |
| let path = self.tcx.def_path(expected.did()).data; |
| let name = path.last().unwrap().data.get_opt_name(); |
| if name == Some(primitive) { |
| return Some(Similar::PrimitiveFound { expected: *expected, found }); |
| } |
| } else if let Some(primitive) = expected.primitive_symbol() |
| && let ty::Adt(found, _) = found.kind() |
| { |
| let path = self.tcx.def_path(found.did()).data; |
| let name = path.last().unwrap().data.get_opt_name(); |
| if name == Some(primitive) { |
| return Some(Similar::PrimitiveExpected { expected, found: *found }); |
| } |
| } else if let ty::Adt(expected, _) = expected.kind() |
| && let ty::Adt(found, _) = found.kind() |
| { |
| if !expected.did().is_local() && expected.did().krate == found.did().krate { |
| // Most likely types from different versions of the same crate |
| // are in play, in which case this message isn't so helpful. |
| // A "perhaps two different versions..." error is already emitted for that. |
| return None; |
| } |
| let f_path = self.tcx.def_path(found.did()).data; |
| let e_path = self.tcx.def_path(expected.did()).data; |
| |
| if let (Some(e_last), Some(f_last)) = (e_path.last(), f_path.last()) |
| && e_last == f_last |
| { |
| return Some(Similar::Adts { expected: *expected, found: *found }); |
| } |
| } |
| None |
| }; |
| |
| match terr { |
| // If two types mismatch but have similar names, mention that specifically. |
| TypeError::Sorts(values) if let Some(s) = similarity(values) => { |
| let diagnose_primitive = |
| |prim: Ty<'tcx>, shadow: Ty<'tcx>, defid: DefId, diag: &mut Diag<'_>| { |
| let name = shadow.sort_string(self.tcx); |
| diag.note(format!( |
| "{prim} and {name} have similar names, but are actually distinct types" |
| )); |
| diag.note(format!("{prim} is a primitive defined by the language")); |
| let def_span = self.tcx.def_span(defid); |
| let msg = if defid.is_local() { |
| format!("{name} is defined in the current crate") |
| } else { |
| let crate_name = self.tcx.crate_name(defid.krate); |
| format!("{name} is defined in crate `{crate_name}`") |
| }; |
| diag.span_note(def_span, msg); |
| }; |
| |
| let diagnose_adts = |
| |expected_adt: ty::AdtDef<'tcx>, |
| found_adt: ty::AdtDef<'tcx>, |
| diag: &mut Diag<'_>| { |
| let found_name = values.found.sort_string(self.tcx); |
| let expected_name = values.expected.sort_string(self.tcx); |
| |
| let found_defid = found_adt.did(); |
| let expected_defid = expected_adt.did(); |
| |
| diag.note(format!("{found_name} and {expected_name} have similar names, but are actually distinct types")); |
| for (defid, name) in |
| [(found_defid, found_name), (expected_defid, expected_name)] |
| { |
| let def_span = self.tcx.def_span(defid); |
| |
| let msg = if found_defid.is_local() && expected_defid.is_local() { |
| let module = self |
| .tcx |
| .parent_module_from_def_id(defid.expect_local()) |
| .to_def_id(); |
| let module_name = |
| self.tcx.def_path(module).to_string_no_crate_verbose(); |
| format!( |
| "{name} is defined in module `crate{module_name}` of the current crate" |
| ) |
| } else if defid.is_local() { |
| format!("{name} is defined in the current crate") |
| } else { |
| let crate_name = self.tcx.crate_name(defid.krate); |
| format!("{name} is defined in crate `{crate_name}`") |
| }; |
| diag.span_note(def_span, msg); |
| } |
| }; |
| |
| match s { |
| Similar::Adts { expected, found } => diagnose_adts(expected, found, diag), |
| Similar::PrimitiveFound { expected, found: prim } => { |
| diagnose_primitive(prim, values.expected, expected.did(), diag) |
| } |
| Similar::PrimitiveExpected { expected: prim, found } => { |
| diagnose_primitive(prim, values.found, found.did(), diag) |
| } |
| } |
| } |
| TypeError::Sorts(values) => { |
| let extra = expected == found; |
| let sort_string = |ty: Ty<'tcx>| match (extra, ty.kind()) { |
| (true, ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. })) => { |
| let sm = self.tcx.sess.source_map(); |
| let pos = sm.lookup_char_pos(self.tcx.def_span(*def_id).lo()); |
| format!( |
| " (opaque type at <{}:{}:{}>)", |
| sm.filename_for_diagnostics(&pos.file.name), |
| pos.line, |
| pos.col.to_usize() + 1, |
| ) |
| } |
| (true, ty::Alias(ty::Projection, proj)) |
| if self.tcx.is_impl_trait_in_trait(proj.def_id) => |
| { |
| let sm = self.tcx.sess.source_map(); |
| let pos = sm.lookup_char_pos(self.tcx.def_span(proj.def_id).lo()); |
| format!( |
| " (trait associated opaque type at <{}:{}:{}>)", |
| sm.filename_for_diagnostics(&pos.file.name), |
| pos.line, |
| pos.col.to_usize() + 1, |
| ) |
| } |
| (true, _) => format!(" ({})", ty.sort_string(self.tcx)), |
| (false, _) => "".to_string(), |
| }; |
| if !(values.expected.is_simple_text(self.tcx) |
| && values.found.is_simple_text(self.tcx)) |
| || (exp_found.is_some_and(|ef| { |
| // This happens when the type error is a subset of the expectation, |
| // like when you have two references but one is `usize` and the other |
| // is `f32`. In those cases we still want to show the `note`. If the |
| // value from `ef` is `Infer(_)`, then we ignore it. |
| if !ef.expected.is_ty_or_numeric_infer() { |
| ef.expected != values.expected |
| } else if !ef.found.is_ty_or_numeric_infer() { |
| ef.found != values.found |
| } else { |
| false |
| } |
| })) |
| { |
| if let Some(ExpectedFound { found: found_ty, .. }) = exp_found { |
| // `Future` is a special opaque type that the compiler |
| // will try to hide in some case such as `async fn`, so |
| // to make an error more use friendly we will |
| // avoid to suggest a mismatch type with a |
| // type that the user usually are not using |
| // directly such as `impl Future<Output = u8>`. |
| if !self.tcx.ty_is_opaque_future(found_ty) { |
| diag.note_expected_found_extra( |
| &expected_label, |
| expected, |
| &found_label, |
| found, |
| &sort_string(values.expected), |
| &sort_string(values.found), |
| ); |
| if let Some(path) = path { |
| diag.note(format!( |
| "the full type name has been written to '{}'", |
| path.display(), |
| )); |
| diag.note("consider using `--verbose` to print the full type name to the console"); |
| } |
| } |
| } |
| } |
| } |
| _ => { |
| debug!( |
| "note_type_err: exp_found={:?}, expected={:?} found={:?}", |
| exp_found, expected, found |
| ); |
| if !is_simple_error || terr.must_include_note() { |
| diag.note_expected_found(&expected_label, expected, &found_label, found); |
| |
| if let Some(ty::Closure(_, args)) = |
| exp_found.map(|expected_type_found| expected_type_found.found.kind()) |
| { |
| diag.highlighted_note(vec![ |
| StringPart::normal("closure has signature: `"), |
| StringPart::highlighted( |
| self.tcx |
| .signature_unclosure( |
| args.as_closure().sig(), |
| rustc_hir::Unsafety::Normal, |
| ) |
| .to_string(), |
| ), |
| StringPart::normal("`"), |
| ]); |
| } |
| } |
| } |
| } |
| } |
| let exp_found = match exp_found { |
| Mismatch::Variable(exp_found) => Some(exp_found), |
| Mismatch::Fixed(_) => None, |
| }; |
| let exp_found = match terr { |
| // `terr` has more accurate type information than `exp_found` in match expressions. |
| ty::error::TypeError::Sorts(terr) |
| if exp_found.is_some_and(|ef| terr.found == ef.found) => |
| { |
| Some(terr) |
| } |
| _ => exp_found, |
| }; |
| debug!("exp_found {:?} terr {:?} cause.code {:?}", exp_found, terr, cause.code()); |
| if let Some(exp_found) = exp_found { |
| let should_suggest_fixes = |
| if let ObligationCauseCode::Pattern { root_ty, .. } = cause.code() { |
| // Skip if the root_ty of the pattern is not the same as the expected_ty. |
| // If these types aren't equal then we've probably peeled off a layer of arrays. |
| self.same_type_modulo_infer(*root_ty, exp_found.expected) |
| } else { |
| true |
| }; |
| |
| // FIXME(#73154): For now, we do leak check when coercing function |
| // pointers in typeck, instead of only during borrowck. This can lead |
| // to these `RegionsInsufficientlyPolymorphic` errors that aren't helpful. |
| if should_suggest_fixes |
| && !matches!(terr, TypeError::RegionsInsufficientlyPolymorphic(..)) |
| { |
| self.suggest_tuple_pattern(cause, &exp_found, diag); |
| self.suggest_accessing_field_where_appropriate(cause, &exp_found, diag); |
| self.suggest_await_on_expect_found(cause, span, &exp_found, diag); |
| self.suggest_function_pointers(cause, span, &exp_found, diag); |
| self.suggest_turning_stmt_into_expr(cause, &exp_found, diag); |
| } |
| } |
| |
| self.check_and_note_conflicting_crates(diag, terr); |
| |
| self.note_and_explain_type_err(diag, terr, cause, span, cause.body_id.to_def_id()); |
| if let Some(exp_found) = exp_found |
| && let exp_found = TypeError::Sorts(exp_found) |
| && exp_found != terr |
| { |
| self.note_and_explain_type_err(diag, exp_found, cause, span, cause.body_id.to_def_id()); |
| } |
| |
| if let Some(ValuePairs::TraitRefs(exp_found)) = values |
| && let ty::Closure(def_id, _) = exp_found.expected.self_ty().kind() |
| && let Some(def_id) = def_id.as_local() |
| && terr.involves_regions() |
| { |
| let span = self.tcx.def_span(def_id); |
| diag.span_note(span, "this closure does not fulfill the lifetime requirements"); |
| self.suggest_for_all_lifetime_closure( |
| span, |
| self.tcx.hir_node_by_def_id(def_id), |
| &exp_found, |
| diag, |
| ); |
| } |
| |
| // It reads better to have the error origin as the final |
| // thing. |
| self.note_error_origin(diag, cause, exp_found, terr); |
| |
| debug!(?diag); |
| } |
| |
| pub fn type_error_additional_suggestions( |
| &self, |
| trace: &TypeTrace<'tcx>, |
| terr: TypeError<'tcx>, |
| ) -> Vec<TypeErrorAdditionalDiags> { |
| use crate::traits::ObligationCauseCode::{BlockTailExpression, MatchExpressionArm}; |
| let mut suggestions = Vec::new(); |
| let span = trace.cause.span(); |
| let values = self.resolve_vars_if_possible(trace.values); |
| if let Some((expected, found)) = values.ty() { |
| match (expected.kind(), found.kind()) { |
| (ty::Tuple(_), ty::Tuple(_)) => {} |
| // If a tuple of length one was expected and the found expression has |
| // parentheses around it, perhaps the user meant to write `(expr,)` to |
| // build a tuple (issue #86100) |
| (ty::Tuple(fields), _) => { |
| suggestions.extend(self.suggest_wrap_to_build_a_tuple(span, found, fields)) |
| } |
| // If a byte was expected and the found expression is a char literal |
| // containing a single ASCII character, perhaps the user meant to write `b'c'` to |
| // specify a byte literal |
| (ty::Uint(ty::UintTy::U8), ty::Char) => { |
| if let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span) |
| && let Some(code) = |
| code.strip_prefix('\'').and_then(|s| s.strip_suffix('\'')) |
| // forbid all Unicode escapes |
| && !code.starts_with("\\u") |
| // forbids literal Unicode characters beyond ASCII |
| && code.chars().next().is_some_and(|c| c.is_ascii()) |
| { |
| suggestions.push(TypeErrorAdditionalDiags::MeantByteLiteral { |
| span, |
| code: escape_literal(code), |
| }) |
| } |
| } |
| // If a character was expected and the found expression is a string literal |
| // containing a single character, perhaps the user meant to write `'c'` to |
| // specify a character literal (issue #92479) |
| (ty::Char, ty::Ref(_, r, _)) if r.is_str() => { |
| if let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span) |
| && let Some(code) = code.strip_prefix('"').and_then(|s| s.strip_suffix('"')) |
| && code.chars().count() == 1 |
| { |
| suggestions.push(TypeErrorAdditionalDiags::MeantCharLiteral { |
| span, |
| code: escape_literal(code), |
| }) |
| } |
| } |
| // If a string was expected and the found expression is a character literal, |
| // perhaps the user meant to write `"s"` to specify a string literal. |
| (ty::Ref(_, r, _), ty::Char) if r.is_str() => { |
| suggestions.push(TypeErrorAdditionalDiags::MeantStrLiteral { |
| start: span.with_hi(span.lo() + BytePos(1)), |
| end: span.with_lo(span.hi() - BytePos(1)), |
| }) |
| } |
| // For code `if Some(..) = expr `, the type mismatch may be expected `bool` but found `()`, |
| // we try to suggest to add the missing `let` for `if let Some(..) = expr` |
| (ty::Bool, ty::Tuple(list)) => { |
| if list.len() == 0 { |
| suggestions.extend(self.suggest_let_for_letchains(&trace.cause, span)); |
| } |
| } |
| (ty::Array(_, _), ty::Array(_, _)) => { |
| suggestions.extend(self.suggest_specify_actual_length(terr, trace, span)) |
| } |
| _ => {} |
| } |
| } |
| let code = trace.cause.code(); |
| if let &(MatchExpressionArm(box MatchExpressionArmCause { source, .. }) |
| | BlockTailExpression(.., source)) = code |
| && let hir::MatchSource::TryDesugar(_) = source |
| && let Some((expected_ty, found_ty, _)) = self.values_str(trace.values) |
| { |
| suggestions.push(TypeErrorAdditionalDiags::TryCannotConvert { |
| found: found_ty.content(), |
| expected: expected_ty.content(), |
| }); |
| } |
| suggestions |
| } |
| |
| fn suggest_specify_actual_length( |
| &self, |
| terr: TypeError<'_>, |
| trace: &TypeTrace<'_>, |
| span: Span, |
| ) -> Option<TypeErrorAdditionalDiags> { |
| let hir = self.tcx.hir(); |
| let TypeError::FixedArraySize(sz) = terr else { |
| return None; |
| }; |
| let tykind = match self.tcx.hir_node_by_def_id(trace.cause.body_id) { |
| hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. }) => { |
| let body = hir.body(*body_id); |
| struct LetVisitor { |
| span: Span, |
| } |
| impl<'v> Visitor<'v> for LetVisitor { |
| type Result = ControlFlow<&'v hir::TyKind<'v>>; |
| fn visit_stmt(&mut self, s: &'v hir::Stmt<'v>) -> Self::Result { |
| // Find a local statement where the initializer has |
| // the same span as the error and the type is specified. |
| if let hir::Stmt { |
| kind: |
| hir::StmtKind::Let(hir::LetStmt { |
| init: Some(hir::Expr { span: init_span, .. }), |
| ty: Some(array_ty), |
| .. |
| }), |
| .. |
| } = s |
| && init_span == &self.span |
| { |
| ControlFlow::Break(&array_ty.peel_refs().kind) |
| } else { |
| ControlFlow::Continue(()) |
| } |
| } |
| } |
| LetVisitor { span }.visit_body(body).break_value() |
| } |
| hir::Node::Item(hir::Item { kind: hir::ItemKind::Const(ty, _, _), .. }) => { |
| Some(&ty.peel_refs().kind) |
| } |
| _ => None, |
| }; |
| if let Some(tykind) = tykind |
| && let hir::TyKind::Array(_, length) = tykind |
| && let hir::ArrayLen::Body(hir::AnonConst { hir_id, .. }) = length |
| { |
| let span = self.tcx.hir().span(*hir_id); |
| Some(TypeErrorAdditionalDiags::ConsiderSpecifyingLength { span, length: sz.found }) |
| } else { |
| None |
| } |
| } |
| |
| pub fn report_and_explain_type_error( |
| &self, |
| trace: TypeTrace<'tcx>, |
| terr: TypeError<'tcx>, |
| ) -> Diag<'tcx> { |
| debug!("report_and_explain_type_error(trace={:?}, terr={:?})", trace, terr); |
| |
| let span = trace.cause.span(); |
| let failure_code = trace.cause.as_failure_code_diag( |
| terr, |
| span, |
| self.type_error_additional_suggestions(&trace, terr), |
| ); |
| let mut diag = self.tcx.dcx().create_err(failure_code); |
| self.note_type_err(&mut diag, &trace.cause, None, Some(trace.values), terr, false, false); |
| diag |
| } |
| |
| fn suggest_wrap_to_build_a_tuple( |
| &self, |
| span: Span, |
| found: Ty<'tcx>, |
| expected_fields: &List<Ty<'tcx>>, |
| ) -> Option<TypeErrorAdditionalDiags> { |
| let [expected_tup_elem] = expected_fields[..] else { return None }; |
| |
| if !self.same_type_modulo_infer(expected_tup_elem, found) { |
| return None; |
| } |
| |
| let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span) else { return None }; |
| |
| let sugg = if code.starts_with('(') && code.ends_with(')') { |
| let before_close = span.hi() - BytePos::from_u32(1); |
| TypeErrorAdditionalDiags::TupleOnlyComma { |
| span: span.with_hi(before_close).shrink_to_hi(), |
| } |
| } else { |
| TypeErrorAdditionalDiags::TupleAlsoParentheses { |
| span_low: span.shrink_to_lo(), |
| span_high: span.shrink_to_hi(), |
| } |
| }; |
| Some(sugg) |
| } |
| |
| fn values_str( |
| &self, |
| values: ValuePairs<'tcx>, |
| ) -> Option<(DiagStyledString, DiagStyledString, Option<PathBuf>)> { |
| match values { |
| infer::Regions(exp_found) => self.expected_found_str(exp_found), |
| infer::Terms(exp_found) => self.expected_found_str_term(exp_found), |
| infer::Aliases(exp_found) => self.expected_found_str(exp_found), |
| infer::ExistentialTraitRef(exp_found) => self.expected_found_str(exp_found), |
| infer::ExistentialProjection(exp_found) => self.expected_found_str(exp_found), |
| infer::TraitRefs(exp_found) => { |
| let pretty_exp_found = ty::error::ExpectedFound { |
| expected: exp_found.expected.print_trait_sugared(), |
| found: exp_found.found.print_trait_sugared(), |
| }; |
| match self.expected_found_str(pretty_exp_found) { |
| Some((expected, found, _)) if expected == found => { |
| self.expected_found_str(exp_found) |
| } |
| ret => ret, |
| } |
| } |
| infer::PolySigs(exp_found) => { |
| let exp_found = self.resolve_vars_if_possible(exp_found); |
| if exp_found.references_error() { |
| return None; |
| } |
| let (exp, fnd) = self.cmp_fn_sig(&exp_found.expected, &exp_found.found); |
| Some((exp, fnd, None)) |
| } |
| } |
| } |
| |
| fn expected_found_str_term( |
| &self, |
| exp_found: ty::error::ExpectedFound<ty::Term<'tcx>>, |
| ) -> Option<(DiagStyledString, DiagStyledString, Option<PathBuf>)> { |
| let exp_found = self.resolve_vars_if_possible(exp_found); |
| if exp_found.references_error() { |
| return None; |
| } |
| |
| Some(match (exp_found.expected.unpack(), exp_found.found.unpack()) { |
| (ty::TermKind::Ty(expected), ty::TermKind::Ty(found)) => { |
| let (mut exp, mut fnd) = self.cmp(expected, found); |
| // Use the terminal width as the basis to determine when to compress the printed |
| // out type, but give ourselves some leeway to avoid ending up creating a file for |
| // a type that is somewhat shorter than the path we'd write to. |
| let len = self.tcx.sess().diagnostic_width() + 40; |
| let exp_s = exp.content(); |
| let fnd_s = fnd.content(); |
| let mut path = None; |
| if exp_s.len() > len { |
| let exp_s = self.tcx.short_ty_string(expected, &mut path); |
| exp = DiagStyledString::highlighted(exp_s); |
| } |
| if fnd_s.len() > len { |
| let fnd_s = self.tcx.short_ty_string(found, &mut path); |
| fnd = DiagStyledString::highlighted(fnd_s); |
| } |
| (exp, fnd, path) |
| } |
| _ => ( |
| DiagStyledString::highlighted(exp_found.expected.to_string()), |
| DiagStyledString::highlighted(exp_found.found.to_string()), |
| None, |
| ), |
| }) |
| } |
| |
| /// Returns a string of the form "expected `{}`, found `{}`". |
| fn expected_found_str<T: fmt::Display + TypeFoldable<TyCtxt<'tcx>>>( |
| &self, |
| exp_found: ty::error::ExpectedFound<T>, |
| ) -> Option<(DiagStyledString, DiagStyledString, Option<PathBuf>)> { |
| let exp_found = self.resolve_vars_if_possible(exp_found); |
| if exp_found.references_error() { |
| return None; |
| } |
| |
| Some(( |
| DiagStyledString::highlighted(exp_found.expected.to_string()), |
| DiagStyledString::highlighted(exp_found.found.to_string()), |
| None, |
| )) |
| } |
| |
| pub fn report_generic_bound_failure( |
| &self, |
| generic_param_scope: LocalDefId, |
| span: Span, |
| origin: Option<SubregionOrigin<'tcx>>, |
| bound_kind: GenericKind<'tcx>, |
| sub: Region<'tcx>, |
| ) -> ErrorGuaranteed { |
| self.construct_generic_bound_failure(generic_param_scope, span, origin, bound_kind, sub) |
| .emit() |
| } |
| |
| pub fn construct_generic_bound_failure( |
| &self, |
| generic_param_scope: LocalDefId, |
| span: Span, |
| origin: Option<SubregionOrigin<'tcx>>, |
| bound_kind: GenericKind<'tcx>, |
| sub: Region<'tcx>, |
| ) -> Diag<'tcx> { |
| if let Some(SubregionOrigin::CompareImplItemObligation { |
| span, |
| impl_item_def_id, |
| trait_item_def_id, |
| }) = origin |
| { |
| return self.report_extra_impl_obligation( |
| span, |
| impl_item_def_id, |
| trait_item_def_id, |
| &format!("`{bound_kind}: {sub}`"), |
| ); |
| } |
| |
| let labeled_user_string = match bound_kind { |
| GenericKind::Param(ref p) => format!("the parameter type `{p}`"), |
| GenericKind::Placeholder(ref p) => format!("the placeholder type `{p:?}`"), |
| GenericKind::Alias(ref p) => match p.kind(self.tcx) { |
| ty::Projection | ty::Inherent => { |
| format!("the associated type `{p}`") |
| } |
| ty::Weak => format!("the type alias `{p}`"), |
| ty::Opaque => format!("the opaque type `{p}`"), |
| }, |
| }; |
| |
| let mut err = self |
| .tcx |
| .dcx() |
| .struct_span_err(span, format!("{labeled_user_string} may not live long enough")); |
| err.code(match sub.kind() { |
| ty::ReEarlyParam(_) | ty::ReLateParam(_) if sub.has_name() => E0309, |
| ty::ReStatic => E0310, |
| _ => E0311, |
| }); |
| |
| '_explain: { |
| let (description, span) = match sub.kind() { |
| ty::ReEarlyParam(_) | ty::ReLateParam(_) | ty::ReStatic => { |
| msg_span_from_named_region(self.tcx, sub, Some(span)) |
| } |
| _ => (format!("lifetime `{sub}`"), Some(span)), |
| }; |
| let prefix = format!("{labeled_user_string} must be valid for "); |
| label_msg_span(&mut err, &prefix, description, span, "..."); |
| if let Some(origin) = origin { |
| self.note_region_origin(&mut err, &origin); |
| } |
| } |
| |
| 'suggestion: { |
| let msg = "consider adding an explicit lifetime bound"; |
| |
| if (bound_kind, sub).has_infer_regions() |
| || (bound_kind, sub).has_placeholders() |
| || !bound_kind.is_suggestable(self.tcx, false) |
| { |
| let lt_name = sub.get_name_or_anon().to_string(); |
| err.help(format!("{msg} `{bound_kind}: {lt_name}`...")); |
| break 'suggestion; |
| } |
| |
| let mut generic_param_scope = generic_param_scope; |
| while self.tcx.def_kind(generic_param_scope) == DefKind::OpaqueTy { |
| generic_param_scope = self.tcx.local_parent(generic_param_scope); |
| } |
| |
| // type_param_sugg_span is (span, has_bounds, needs_parentheses) |
| let (type_scope, type_param_sugg_span) = match bound_kind { |
| GenericKind::Param(param) => { |
| let generics = self.tcx.generics_of(generic_param_scope); |
| let def_id = generics.type_param(param, self.tcx).def_id.expect_local(); |
| let scope = self.tcx.local_def_id_to_hir_id(def_id).owner.def_id; |
| // Get the `hir::Param` to verify whether it already has any bounds. |
| // We do this to avoid suggesting code that ends up as `T: 'a'b`, |
| // instead we suggest `T: 'a + 'b` in that case. |
| let hir_generics = self.tcx.hir().get_generics(scope).unwrap(); |
| let sugg_span = match hir_generics.bounds_span_for_suggestions(def_id) { |
| Some((span, open_paren_sp)) => Some((span, true, open_paren_sp)), |
| // If `param` corresponds to `Self`, no usable suggestion span. |
| None if generics.has_self && param.index == 0 => None, |
| None => Some((self.tcx.def_span(def_id).shrink_to_hi(), false, None)), |
| }; |
| (scope, sugg_span) |
| } |
| _ => (generic_param_scope, None), |
| }; |
| let suggestion_scope = { |
| let lifetime_scope = match sub.kind() { |
| ty::ReStatic => hir::def_id::CRATE_DEF_ID, |
| _ => match self.tcx.is_suitable_region(sub) { |
| Some(info) => info.def_id, |
| None => generic_param_scope, |
| }, |
| }; |
| match self.tcx.is_descendant_of(type_scope.into(), lifetime_scope.into()) { |
| true => type_scope, |
| false => lifetime_scope, |
| } |
| }; |
| |
| let mut suggs = vec![]; |
| let lt_name = self.suggest_name_region(sub, &mut suggs); |
| |
| if let Some((sp, has_lifetimes, open_paren_sp)) = type_param_sugg_span |
| && suggestion_scope == type_scope |
| { |
| let suggestion = |
| if has_lifetimes { format!(" + {lt_name}") } else { format!(": {lt_name}") }; |
| |
| if let Some(open_paren_sp) = open_paren_sp { |
| suggs.push((open_paren_sp, "(".to_string())); |
| suggs.push((sp, format!("){suggestion}"))); |
| } else { |
| suggs.push((sp, suggestion)) |
| } |
| } else if let GenericKind::Alias(ref p) = bound_kind |
| && let ty::Projection = p.kind(self.tcx) |
| && let DefKind::AssocTy = self.tcx.def_kind(p.def_id) |
| && let Some(ty::ImplTraitInTraitData::Trait { .. }) = |
| self.tcx.opt_rpitit_info(p.def_id) |
| { |
| // The lifetime found in the `impl` is longer than the one on the RPITIT. |
| // Do not suggest `<Type as Trait>::{opaque}: 'static`. |
| } else if let Some(generics) = self.tcx.hir().get_generics(suggestion_scope) { |
| let pred = format!("{bound_kind}: {lt_name}"); |
| let suggestion = format!("{} {}", generics.add_where_or_trailing_comma(), pred); |
| suggs.push((generics.tail_span_for_predicate_suggestion(), suggestion)) |
| } else { |
| let consider = format!("{msg} `{bound_kind}: {sub}`..."); |
| err.help(consider); |
| } |
| |
| if !suggs.is_empty() { |
| err.multipart_suggestion_verbose( |
| msg, |
| suggs, |
| Applicability::MaybeIncorrect, // Issue #41966 |
| ); |
| } |
| } |
| |
| err |
| } |
| |
| pub fn suggest_name_region( |
| &self, |
| lifetime: Region<'tcx>, |
| add_lt_suggs: &mut Vec<(Span, String)>, |
| ) -> String { |
| struct LifetimeReplaceVisitor<'tcx, 'a> { |
| tcx: TyCtxt<'tcx>, |
| needle: hir::LifetimeName, |
| new_lt: &'a str, |
| add_lt_suggs: &'a mut Vec<(Span, String)>, |
| } |
| |
| impl<'hir, 'tcx> hir::intravisit::Visitor<'hir> for LifetimeReplaceVisitor<'tcx, '_> { |
| fn visit_lifetime(&mut self, lt: &'hir hir::Lifetime) { |
| if lt.res == self.needle { |
| let (pos, span) = lt.suggestion_position(); |
| let new_lt = &self.new_lt; |
| let sugg = match pos { |
| hir::LifetimeSuggestionPosition::Normal => format!("{new_lt}"), |
| hir::LifetimeSuggestionPosition::Ampersand => format!("{new_lt} "), |
| hir::LifetimeSuggestionPosition::ElidedPath => format!("<{new_lt}>"), |
| hir::LifetimeSuggestionPosition::ElidedPathArgument => { |
| format!("{new_lt}, ") |
| } |
| hir::LifetimeSuggestionPosition::ObjectDefault => format!("+ {new_lt}"), |
| }; |
| self.add_lt_suggs.push((span, sugg)); |
| } |
| } |
| |
| fn visit_ty(&mut self, ty: &'hir hir::Ty<'hir>) { |
| let hir::TyKind::OpaqueDef(item_id, _, _) = ty.kind else { |
| return hir::intravisit::walk_ty(self, ty); |
| }; |
| let opaque_ty = self.tcx.hir().item(item_id).expect_opaque_ty(); |
| if let Some(&(_, b)) = |
| opaque_ty.lifetime_mapping.iter().find(|&(a, _)| a.res == self.needle) |
| { |
| let prev_needle = |
| std::mem::replace(&mut self.needle, hir::LifetimeName::Param(b)); |
| for bound in opaque_ty.bounds { |
| self.visit_param_bound(bound); |
| } |
| self.needle = prev_needle; |
| } |
| } |
| } |
| |
| let (lifetime_def_id, lifetime_scope) = match self.tcx.is_suitable_region(lifetime) { |
| Some(info) if !lifetime.has_name() => { |
| (info.bound_region.get_id().unwrap().expect_local(), info.def_id) |
| } |
| _ => return lifetime.get_name_or_anon().to_string(), |
| }; |
| |
| let new_lt = { |
| let generics = self.tcx.generics_of(lifetime_scope); |
| let mut used_names = |
| iter::successors(Some(generics), |g| g.parent.map(|p| self.tcx.generics_of(p))) |
| .flat_map(|g| &g.own_params) |
| .filter(|p| matches!(p.kind, ty::GenericParamDefKind::Lifetime)) |
| .map(|p| p.name) |
| .collect::<Vec<_>>(); |
| let hir_id = self.tcx.local_def_id_to_hir_id(lifetime_scope); |
| // consider late-bound lifetimes ... |
| used_names.extend(self.tcx.late_bound_vars(hir_id).into_iter().filter_map( |
| |p| match p { |
| ty::BoundVariableKind::Region(lt) => lt.get_name(), |
| _ => None, |
| }, |
| )); |
| (b'a'..=b'z') |
| .map(|c| format!("'{}", c as char)) |
| .find(|candidate| !used_names.iter().any(|e| e.as_str() == candidate)) |
| .unwrap_or("'lt".to_string()) |
| }; |
| |
| let mut visitor = LifetimeReplaceVisitor { |
| tcx: self.tcx, |
| needle: hir::LifetimeName::Param(lifetime_def_id), |
| add_lt_suggs, |
| new_lt: &new_lt, |
| }; |
| match self.tcx.expect_hir_owner_node(lifetime_scope) { |
| hir::OwnerNode::Item(i) => visitor.visit_item(i), |
| hir::OwnerNode::ForeignItem(i) => visitor.visit_foreign_item(i), |
| hir::OwnerNode::ImplItem(i) => visitor.visit_impl_item(i), |
| hir::OwnerNode::TraitItem(i) => visitor.visit_trait_item(i), |
| hir::OwnerNode::Crate(_) => bug!("OwnerNode::Crate doesn't not have generics"), |
| hir::OwnerNode::Synthetic => unreachable!(), |
| } |
| |
| let ast_generics = self.tcx.hir().get_generics(lifetime_scope).unwrap(); |
| let sugg = ast_generics |
| .span_for_lifetime_suggestion() |
| .map(|span| (span, format!("{new_lt}, "))) |
| .unwrap_or_else(|| (ast_generics.span, format!("<{new_lt}>"))); |
| add_lt_suggs.push(sugg); |
| |
| new_lt |
| } |
| |
| fn report_sub_sup_conflict( |
| &self, |
| var_origin: RegionVariableOrigin, |
| sub_origin: SubregionOrigin<'tcx>, |
| sub_region: Region<'tcx>, |
| sup_origin: SubregionOrigin<'tcx>, |
| sup_region: Region<'tcx>, |
| ) -> ErrorGuaranteed { |
| let mut err = self.report_inference_failure(var_origin); |
| |
| note_and_explain_region( |
| self.tcx, |
| &mut err, |
| "first, the lifetime cannot outlive ", |
| sup_region, |
| "...", |
| None, |
| ); |
| |
| debug!("report_sub_sup_conflict: var_origin={:?}", var_origin); |
| debug!("report_sub_sup_conflict: sub_region={:?}", sub_region); |
| debug!("report_sub_sup_conflict: sub_origin={:?}", sub_origin); |
| debug!("report_sub_sup_conflict: sup_region={:?}", sup_region); |
| debug!("report_sub_sup_conflict: sup_origin={:?}", sup_origin); |
| |
| if let infer::Subtype(ref sup_trace) = sup_origin |
| && let infer::Subtype(ref sub_trace) = sub_origin |
| && let Some((sup_expected, sup_found, _)) = self.values_str(sup_trace.values) |
| && let Some((sub_expected, sub_found, _)) = self.values_str(sub_trace.values) |
| && sub_expected == sup_expected |
| && sub_found == sup_found |
| { |
| note_and_explain_region( |
| self.tcx, |
| &mut err, |
| "...but the lifetime must also be valid for ", |
| sub_region, |
| "...", |
| None, |
| ); |
| err.span_note( |
| sup_trace.cause.span, |
| format!("...so that the {}", sup_trace.cause.as_requirement_str()), |
| ); |
| |
| err.note_expected_found(&"", sup_expected, &"", sup_found); |
| return if sub_region.is_error() | sup_region.is_error() { |
| err.delay_as_bug() |
| } else { |
| err.emit() |
| }; |
| } |
| |
| self.note_region_origin(&mut err, &sup_origin); |
| |
| note_and_explain_region( |
| self.tcx, |
| &mut err, |
| "but, the lifetime must be valid for ", |
| sub_region, |
| "...", |
| None, |
| ); |
| |
| self.note_region_origin(&mut err, &sub_origin); |
| if sub_region.is_error() | sup_region.is_error() { err.delay_as_bug() } else { err.emit() } |
| } |
| |
| /// Determine whether an error associated with the given span and definition |
| /// should be treated as being caused by the implicit `From` conversion |
| /// within `?` desugaring. |
| pub fn is_try_conversion(&self, span: Span, trait_def_id: DefId) -> bool { |
| span.is_desugaring(DesugaringKind::QuestionMark) |
| && self.tcx.is_diagnostic_item(sym::From, trait_def_id) |
| } |
| |
| /// Structurally compares two types, modulo any inference variables. |
| /// |
| /// Returns `true` if two types are equal, or if one type is an inference variable compatible |
| /// with the other type. A TyVar inference type is compatible with any type, and an IntVar or |
| /// FloatVar inference type are compatible with themselves or their concrete types (Int and |
| /// Float types, respectively). When comparing two ADTs, these rules apply recursively. |
| pub fn same_type_modulo_infer<T: relate::Relate<'tcx>>(&self, a: T, b: T) -> bool { |
| let (a, b) = self.resolve_vars_if_possible((a, b)); |
| SameTypeModuloInfer(self).relate(a, b).is_ok() |
| } |
| } |
| |
| struct SameTypeModuloInfer<'a, 'tcx>(&'a InferCtxt<'tcx>); |
| |
| impl<'tcx> TypeRelation<'tcx> for SameTypeModuloInfer<'_, 'tcx> { |
| fn tcx(&self) -> TyCtxt<'tcx> { |
| self.0.tcx |
| } |
| |
| fn tag(&self) -> &'static str { |
| "SameTypeModuloInfer" |
| } |
| |
| fn relate_with_variance<T: relate::Relate<'tcx>>( |
| &mut self, |
| _variance: ty::Variance, |
| _info: ty::VarianceDiagInfo<'tcx>, |
| a: T, |
| b: T, |
| ) -> relate::RelateResult<'tcx, T> { |
| self.relate(a, b) |
| } |
| |
| fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> { |
| match (a.kind(), b.kind()) { |
| (ty::Int(_) | ty::Uint(_), ty::Infer(ty::InferTy::IntVar(_))) |
| | ( |
| ty::Infer(ty::InferTy::IntVar(_)), |
| ty::Int(_) | ty::Uint(_) | ty::Infer(ty::InferTy::IntVar(_)), |
| ) |
| | (ty::Float(_), ty::Infer(ty::InferTy::FloatVar(_))) |
| | ( |
| ty::Infer(ty::InferTy::FloatVar(_)), |
| ty::Float(_) | ty::Infer(ty::InferTy::FloatVar(_)), |
| ) |
| | (ty::Infer(ty::InferTy::TyVar(_)), _) |
| | (_, ty::Infer(ty::InferTy::TyVar(_))) => Ok(a), |
| (ty::Infer(_), _) | (_, ty::Infer(_)) => Err(TypeError::Mismatch), |
| _ => relate::structurally_relate_tys(self, a, b), |
| } |
| } |
| |
| fn regions( |
| &mut self, |
| a: ty::Region<'tcx>, |
| b: ty::Region<'tcx>, |
| ) -> RelateResult<'tcx, ty::Region<'tcx>> { |
| if (a.is_var() && b.is_free()) |
| || (b.is_var() && a.is_free()) |
| || (a.is_var() && b.is_var()) |
| || a == b |
| { |
| Ok(a) |
| } else { |
| Err(TypeError::Mismatch) |
| } |
| } |
| |
| fn binders<T>( |
| &mut self, |
| a: ty::Binder<'tcx, T>, |
| b: ty::Binder<'tcx, T>, |
| ) -> relate::RelateResult<'tcx, ty::Binder<'tcx, T>> |
| where |
| T: relate::Relate<'tcx>, |
| { |
| Ok(a.rebind(self.relate(a.skip_binder(), b.skip_binder())?)) |
| } |
| |
| fn consts( |
| &mut self, |
| a: ty::Const<'tcx>, |
| _b: ty::Const<'tcx>, |
| ) -> relate::RelateResult<'tcx, ty::Const<'tcx>> { |
| // FIXME(compiler-errors): This could at least do some first-order |
| // relation |
| Ok(a) |
| } |
| } |
| |
| impl<'tcx> InferCtxt<'tcx> { |
| fn report_inference_failure(&self, var_origin: RegionVariableOrigin) -> Diag<'tcx> { |
| let br_string = |br: ty::BoundRegionKind| { |
| let mut s = match br { |
| ty::BrNamed(_, name) => name.to_string(), |
| _ => String::new(), |
| }; |
| if !s.is_empty() { |
| s.push(' '); |
| } |
| s |
| }; |
| let var_description = match var_origin { |
| infer::MiscVariable(_) => String::new(), |
| infer::PatternRegion(_) => " for pattern".to_string(), |
| infer::AddrOfRegion(_) => " for borrow expression".to_string(), |
| infer::Autoref(_) => " for autoref".to_string(), |
| infer::Coercion(_) => " for automatic coercion".to_string(), |
| infer::BoundRegion(_, br, infer::FnCall) => { |
| format!(" for lifetime parameter {}in function call", br_string(br)) |
| } |
| infer::BoundRegion(_, br, infer::HigherRankedType) => { |
| format!(" for lifetime parameter {}in generic type", br_string(br)) |
| } |
| infer::BoundRegion(_, br, infer::AssocTypeProjection(def_id)) => format!( |
| " for lifetime parameter {}in trait containing associated type `{}`", |
| br_string(br), |
| self.tcx.associated_item(def_id).name |
| ), |
| infer::RegionParameterDefinition(_, name) => { |
| format!(" for lifetime parameter `{name}`") |
| } |
| infer::UpvarRegion(ref upvar_id, _) => { |
| let var_name = self.tcx.hir().name(upvar_id.var_path.hir_id); |
| format!(" for capture of `{var_name}` by closure") |
| } |
| infer::Nll(..) => bug!("NLL variable found in lexical phase"), |
| }; |
| |
| struct_span_code_err!( |
| self.tcx.dcx(), |
| var_origin.span(), |
| E0495, |
| "cannot infer an appropriate lifetime{} due to conflicting requirements", |
| var_description |
| ) |
| } |
| } |
| |
| pub enum FailureCode { |
| Error0317, |
| Error0580, |
| Error0308, |
| Error0644, |
| } |
| |
| #[extension(pub trait ObligationCauseExt<'tcx>)] |
| impl<'tcx> ObligationCause<'tcx> { |
| fn as_failure_code(&self, terr: TypeError<'tcx>) -> FailureCode { |
| use self::FailureCode::*; |
| use crate::traits::ObligationCauseCode::*; |
| match self.code() { |
| IfExpressionWithNoElse => Error0317, |
| MainFunctionType => Error0580, |
| CompareImplItemObligation { .. } |
| | MatchExpressionArm(_) |
| | IfExpression { .. } |
| | LetElse |
| | StartFunctionType |
| | LangFunctionType(_) |
| | IntrinsicType |
| | MethodReceiver => Error0308, |
| |
| // In the case where we have no more specific thing to |
| // say, also take a look at the error code, maybe we can |
| // tailor to that. |
| _ => match terr { |
| TypeError::CyclicTy(ty) |
| if ty.is_closure() || ty.is_coroutine() || ty.is_coroutine_closure() => |
| { |
| Error0644 |
| } |
| TypeError::IntrinsicCast => Error0308, |
| _ => Error0308, |
| }, |
| } |
| } |
| fn as_failure_code_diag( |
| &self, |
| terr: TypeError<'tcx>, |
| span: Span, |
| subdiags: Vec<TypeErrorAdditionalDiags>, |
| ) -> ObligationCauseFailureCode { |
| use crate::traits::ObligationCauseCode::*; |
| match self.code() { |
| CompareImplItemObligation { kind: ty::AssocKind::Fn, .. } => { |
| ObligationCauseFailureCode::MethodCompat { span, subdiags } |
| } |
| CompareImplItemObligation { kind: ty::AssocKind::Type, .. } => { |
| ObligationCauseFailureCode::TypeCompat { span, subdiags } |
| } |
| CompareImplItemObligation { kind: ty::AssocKind::Const, .. } => { |
| ObligationCauseFailureCode::ConstCompat { span, subdiags } |
| } |
| BlockTailExpression(.., hir::MatchSource::TryDesugar(_)) => { |
| ObligationCauseFailureCode::TryCompat { span, subdiags } |
| } |
| MatchExpressionArm(box MatchExpressionArmCause { source, .. }) => match source { |
| hir::MatchSource::TryDesugar(_) => { |
| ObligationCauseFailureCode::TryCompat { span, subdiags } |
| } |
| _ => ObligationCauseFailureCode::MatchCompat { span, subdiags }, |
| }, |
| IfExpression { .. } => ObligationCauseFailureCode::IfElseDifferent { span, subdiags }, |
| IfExpressionWithNoElse => ObligationCauseFailureCode::NoElse { span }, |
| LetElse => ObligationCauseFailureCode::NoDiverge { span, subdiags }, |
| MainFunctionType => ObligationCauseFailureCode::FnMainCorrectType { span }, |
| StartFunctionType => ObligationCauseFailureCode::FnStartCorrectType { span, subdiags }, |
| &LangFunctionType(lang_item_name) => { |
| ObligationCauseFailureCode::FnLangCorrectType { span, subdiags, lang_item_name } |
| } |
| IntrinsicType => ObligationCauseFailureCode::IntrinsicCorrectType { span, subdiags }, |
| MethodReceiver => ObligationCauseFailureCode::MethodCorrectType { span, subdiags }, |
| |
| // In the case where we have no more specific thing to |
| // say, also take a look at the error code, maybe we can |
| // tailor to that. |
| _ => match terr { |
| TypeError::CyclicTy(ty) |
| if ty.is_closure() || ty.is_coroutine() || ty.is_coroutine_closure() => |
| { |
| ObligationCauseFailureCode::ClosureSelfref { span } |
| } |
| TypeError::IntrinsicCast => { |
| ObligationCauseFailureCode::CantCoerce { span, subdiags } |
| } |
| _ => ObligationCauseFailureCode::Generic { span, subdiags }, |
| }, |
| } |
| } |
| |
| fn as_requirement_str(&self) -> &'static str { |
| use crate::traits::ObligationCauseCode::*; |
| match self.code() { |
| CompareImplItemObligation { kind: ty::AssocKind::Fn, .. } => { |
| "method type is compatible with trait" |
| } |
| CompareImplItemObligation { kind: ty::AssocKind::Type, .. } => { |
| "associated type is compatible with trait" |
| } |
| CompareImplItemObligation { kind: ty::AssocKind::Const, .. } => { |
| "const is compatible with trait" |
| } |
| MainFunctionType => "`main` function has the correct type", |
| StartFunctionType => "`#[start]` function has the correct type", |
| LangFunctionType(_) => "lang item function has the correct type", |
| IntrinsicType => "intrinsic has the correct type", |
| MethodReceiver => "method receiver has the correct type", |
| _ => "types are compatible", |
| } |
| } |
| } |
| |
| /// Newtype to allow implementing IntoDiagArg |
| pub struct ObligationCauseAsDiagArg<'tcx>(pub ObligationCause<'tcx>); |
| |
| impl IntoDiagArg for ObligationCauseAsDiagArg<'_> { |
| fn into_diag_arg(self) -> rustc_errors::DiagArgValue { |
| use crate::traits::ObligationCauseCode::*; |
| let kind = match self.0.code() { |
| CompareImplItemObligation { kind: ty::AssocKind::Fn, .. } => "method_compat", |
| CompareImplItemObligation { kind: ty::AssocKind::Type, .. } => "type_compat", |
| CompareImplItemObligation { kind: ty::AssocKind::Const, .. } => "const_compat", |
| MainFunctionType => "fn_main_correct_type", |
| StartFunctionType => "fn_start_correct_type", |
| LangFunctionType(_) => "fn_lang_correct_type", |
| IntrinsicType => "intrinsic_correct_type", |
| MethodReceiver => "method_correct_type", |
| _ => "other", |
| } |
| .into(); |
| rustc_errors::DiagArgValue::Str(kind) |
| } |
| } |
| |
| /// This is a bare signal of what kind of type we're dealing with. `ty::TyKind` tracks |
| /// extra information about each type, but we only care about the category. |
| #[derive(Clone, Copy, PartialEq, Eq, Hash)] |
| pub enum TyCategory { |
| Closure, |
| Opaque, |
| OpaqueFuture, |
| Coroutine(hir::CoroutineKind), |
| Foreign, |
| } |
| |
| impl fmt::Display for TyCategory { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| match self { |
| Self::Closure => "closure".fmt(f), |
| Self::Opaque => "opaque type".fmt(f), |
| Self::OpaqueFuture => "future".fmt(f), |
| Self::Coroutine(gk) => gk.fmt(f), |
| Self::Foreign => "foreign type".fmt(f), |
| } |
| } |
| } |
| |
| impl TyCategory { |
| pub fn from_ty(tcx: TyCtxt<'_>, ty: Ty<'_>) -> Option<(Self, DefId)> { |
| match *ty.kind() { |
| ty::Closure(def_id, _) => Some((Self::Closure, def_id)), |
| ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) => { |
| let kind = |
| if tcx.ty_is_opaque_future(ty) { Self::OpaqueFuture } else { Self::Opaque }; |
| Some((kind, def_id)) |
| } |
| ty::Coroutine(def_id, ..) => { |
| Some((Self::Coroutine(tcx.coroutine_kind(def_id).unwrap()), def_id)) |
| } |
| ty::Foreign(def_id) => Some((Self::Foreign, def_id)), |
| _ => None, |
| } |
| } |
| } |
| |
| impl<'tcx> InferCtxt<'tcx> { |
| /// Given a [`hir::Block`], get the span of its last expression or |
| /// statement, peeling off any inner blocks. |
| pub fn find_block_span(&self, block: &'tcx hir::Block<'tcx>) -> Span { |
| let block = block.innermost_block(); |
| if let Some(expr) = &block.expr { |
| expr.span |
| } else if let Some(stmt) = block.stmts.last() { |
| // possibly incorrect trailing `;` in the else arm |
| stmt.span |
| } else { |
| // empty block; point at its entirety |
| block.span |
| } |
| } |
| |
| /// Given a [`hir::HirId`] for a block, get the span of its last expression |
| /// or statement, peeling off any inner blocks. |
| pub fn find_block_span_from_hir_id(&self, hir_id: hir::HirId) -> Span { |
| match self.tcx.hir_node(hir_id) { |
| hir::Node::Block(blk) => self.find_block_span(blk), |
| // The parser was in a weird state if either of these happen, but |
| // it's better not to panic. |
| hir::Node::Expr(e) => e.span, |
| _ => rustc_span::DUMMY_SP, |
| } |
| } |
| } |