diff options
Diffstat (limited to 'compiler/rustc_hir_typeck/src/method/probe.rs')
| -rw-r--r-- | compiler/rustc_hir_typeck/src/method/probe.rs | 279 |
1 files changed, 188 insertions, 91 deletions
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs index ae299cc9d..a24814313 100644 --- a/compiler/rustc_hir_typeck/src/method/probe.rs +++ b/compiler/rustc_hir_typeck/src/method/probe.rs @@ -9,6 +9,7 @@ use rustc_data_structures::fx::FxHashSet; use rustc_errors::Applicability; use rustc_hir as hir; use rustc_hir::def::DefKind; +use rustc_hir_analysis::autoderef::{self, Autoderef}; use rustc_infer::infer::canonical::OriginalQueryValues; use rustc_infer::infer::canonical::{Canonical, QueryResponse}; use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; @@ -29,7 +30,6 @@ use rustc_span::lev_distance::{ }; use rustc_span::symbol::sym; use rustc_span::{symbol::Ident, Span, Symbol, DUMMY_SP}; -use rustc_trait_selection::autoderef::{self, Autoderef}; use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt; use rustc_trait_selection::traits::query::method_autoderef::MethodAutoderefBadTy; use rustc_trait_selection::traits::query::method_autoderef::{ @@ -38,9 +38,9 @@ use rustc_trait_selection::traits::query::method_autoderef::{ use rustc_trait_selection::traits::query::CanonicalTyGoal; use rustc_trait_selection::traits::NormalizeExt; use rustc_trait_selection::traits::{self, ObligationCause}; +use std::cell::RefCell; use std::cmp::max; use std::iter; -use std::mem; use std::ops::Deref; use smallvec::{smallvec, SmallVec}; @@ -62,28 +62,29 @@ struct ProbeContext<'a, 'tcx> { /// This is the OriginalQueryValues for the steps queries /// that are answered in steps. - orig_steps_var_values: OriginalQueryValues<'tcx>, + orig_steps_var_values: &'a OriginalQueryValues<'tcx>, steps: &'tcx [CandidateStep<'tcx>], inherent_candidates: Vec<Candidate<'tcx>>, extension_candidates: Vec<Candidate<'tcx>>, impl_dups: FxHashSet<DefId>, - /// Collects near misses when the candidate functions are missing a `self` keyword and is only - /// used for error reporting - static_candidates: Vec<CandidateSource>, - /// When probing for names, include names that are close to the - /// requested name (by Levensthein distance) + /// requested name (by Levenshtein distance) allow_similar_names: bool, /// Some(candidate) if there is a private candidate private_candidate: Option<(DefKind, DefId)>, + /// Collects near misses when the candidate functions are missing a `self` keyword and is only + /// used for error reporting + static_candidates: RefCell<Vec<CandidateSource>>, + /// Collects near misses when trait bounds for type parameters are unsatisfied and is only used /// for error reporting - unsatisfied_predicates: + unsatisfied_predicates: RefCell< Vec<(ty::Predicate<'tcx>, Option<ty::Predicate<'tcx>>, Option<ObligationCause<'tcx>>)>, + >, scope_expr_id: hir::HirId, } @@ -96,7 +97,7 @@ impl<'a, 'tcx> Deref for ProbeContext<'a, 'tcx> { } #[derive(Debug, Clone)] -struct Candidate<'tcx> { +pub(crate) struct Candidate<'tcx> { // Candidates are (I'm not quite sure, but they are mostly) basically // some metadata on top of a `ty::AssocItem` (without substs). // @@ -130,13 +131,13 @@ struct Candidate<'tcx> { // if `T: Sized`. xform_self_ty: Ty<'tcx>, xform_ret_ty: Option<Ty<'tcx>>, - item: ty::AssocItem, - kind: CandidateKind<'tcx>, - import_ids: SmallVec<[LocalDefId; 1]>, + pub(crate) item: ty::AssocItem, + pub(crate) kind: CandidateKind<'tcx>, + pub(crate) import_ids: SmallVec<[LocalDefId; 1]>, } #[derive(Debug, Clone)] -enum CandidateKind<'tcx> { +pub(crate) enum CandidateKind<'tcx> { InherentImplCandidate( SubstsRef<'tcx>, // Normalize obligations @@ -231,7 +232,7 @@ pub type PickResult<'tcx> = Result<Pick<'tcx>, MethodError<'tcx>>; pub enum Mode { // An expression of the form `receiver.method_name(...)`. // Autoderefs are performed on `receiver`, lookup is done based on the - // `self` argument of the method, and static methods aren't considered. + // `self` argument of the method, and static methods aren't considered. MethodCall, // An expression of the form `Type::item` or `<T>::item`. // No autoderefs are performed, lookup is done based on the type each @@ -303,6 +304,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { &self, mode: Mode, item_name: Ident, + return_type: Option<Ty<'tcx>>, is_suggestion: IsSuggestion, self_ty: Ty<'tcx>, scope_expr_id: hir::HirId, @@ -312,7 +314,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { item_name.span, mode, Some(item_name), - None, + return_type, is_suggestion, self_ty, scope_expr_id, @@ -321,6 +323,37 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { ) } + #[instrument(level = "debug", skip(self))] + pub(crate) fn probe_for_name_many( + &self, + mode: Mode, + item_name: Ident, + return_type: Option<Ty<'tcx>>, + is_suggestion: IsSuggestion, + self_ty: Ty<'tcx>, + scope_expr_id: hir::HirId, + scope: ProbeScope, + ) -> Vec<Candidate<'tcx>> { + self.probe_op( + item_name.span, + mode, + Some(item_name), + return_type, + is_suggestion, + self_ty, + scope_expr_id, + scope, + |probe_cx| { + Ok(probe_cx + .inherent_candidates + .into_iter() + .chain(probe_cx.extension_candidates) + .collect()) + }, + ) + .unwrap() + } + fn probe_op<OP, R>( &'a self, span: Span, @@ -334,7 +367,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { op: OP, ) -> Result<R, MethodError<'tcx>> where - OP: FnOnce(ProbeContext<'a, 'tcx>) -> Result<R, MethodError<'tcx>>, + OP: FnOnce(ProbeContext<'_, 'tcx>) -> Result<R, MethodError<'tcx>>, { let mut orig_values = OriginalQueryValues::default(); let param_env_and_self_ty = self.canonicalize_query( @@ -445,7 +478,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { mode, method_name, return_type, - orig_values, + &orig_values, steps.steps, scope_expr_id, ); @@ -453,7 +486,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { probe_cx.assemble_inherent_candidates(); match scope { ProbeScope::TraitsInScope => { - probe_cx.assemble_extension_candidates_for_traits_in_scope(scope_expr_id) + probe_cx.assemble_extension_candidates_for_traits_in_scope() } ProbeScope::AllTraits => probe_cx.assemble_extension_candidates_for_all_traits(), }; @@ -539,7 +572,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { mode: Mode, method_name: Option<Ident>, return_type: Option<Ty<'tcx>>, - orig_steps_var_values: OriginalQueryValues<'tcx>, + orig_steps_var_values: &'a OriginalQueryValues<'tcx>, steps: &'tcx [CandidateStep<'tcx>], scope_expr_id: hir::HirId, ) -> ProbeContext<'a, 'tcx> { @@ -554,10 +587,10 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { impl_dups: FxHashSet::default(), orig_steps_var_values, steps, - static_candidates: Vec::new(), allow_similar_names: false, private_candidate: None, - unsatisfied_predicates: Vec::new(), + static_candidates: RefCell::new(Vec::new()), + unsatisfied_predicates: RefCell::new(Vec::new()), scope_expr_id, } } @@ -566,8 +599,9 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { self.inherent_candidates.clear(); self.extension_candidates.clear(); self.impl_dups.clear(); - self.static_candidates.clear(); self.private_candidate = None; + self.static_candidates.borrow_mut().clear(); + self.unsatisfied_predicates.borrow_mut().clear(); } /////////////////////////////////////////////////////////////////////////// @@ -855,9 +889,9 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { } } - fn assemble_extension_candidates_for_traits_in_scope(&mut self, expr_hir_id: hir::HirId) { + fn assemble_extension_candidates_for_traits_in_scope(&mut self) { let mut duplicates = FxHashSet::default(); - let opt_applicable_traits = self.tcx.in_scope_traits(expr_hir_id); + let opt_applicable_traits = self.tcx.in_scope_traits(self.scope_expr_id); if let Some(applicable_traits) = opt_applicable_traits { for trait_candidate in applicable_traits.iter() { let trait_did = trait_candidate.def_id; @@ -918,7 +952,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { ) { debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})", trait_def_id); let trait_substs = self.fresh_item_substs(trait_def_id); - let trait_ref = ty::TraitRef::new(trait_def_id, trait_substs); + let trait_ref = self.tcx.mk_trait_ref(trait_def_id, trait_substs); if self.tcx.is_trait_alias(trait_def_id) { // For trait aliases, assume all supertraits are relevant. @@ -941,6 +975,9 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { }); } else { debug_assert!(self.tcx.is_trait(trait_def_id)); + if self.tcx.trait_is_auto(trait_def_id) { + return; + } for item in self.impl_or_trait_item(trait_def_id) { // Check whether `trait_def_id` defines a method with suitable name. if !self.has_applicable_self(&item) { @@ -1003,9 +1040,9 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { debug!("pick: actual search failed, assemble diagnostics"); - let static_candidates = mem::take(&mut self.static_candidates); + let static_candidates = std::mem::take(self.static_candidates.get_mut()); let private_candidate = self.private_candidate.take(); - let unsatisfied_predicates = mem::take(&mut self.unsatisfied_predicates); + let unsatisfied_predicates = std::mem::take(self.unsatisfied_predicates.get_mut()); // things failed, so lets look at all traits, for diagnostic purposes now: self.reset(); @@ -1050,7 +1087,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { })) } - fn pick_core(&mut self) -> Option<PickResult<'tcx>> { + fn pick_core(&self) -> Option<PickResult<'tcx>> { let pick = self.pick_all_method(Some(&mut vec![])); // In this case unstable picking is done by `pick_method`. @@ -1065,11 +1102,10 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { } fn pick_all_method( - &mut self, + &self, mut unstable_candidates: Option<&mut Vec<(Candidate<'tcx>, Symbol)>>, ) -> Option<PickResult<'tcx>> { - let steps = self.steps.clone(); - steps + self.steps .iter() .filter(|step| { debug!("pick_all_method: step={:?}", step); @@ -1077,7 +1113,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { // a raw pointer !step.self_ty.references_error() && !step.from_unsafe_deref }) - .flat_map(|step| { + .find_map(|step| { let InferOk { value: self_ty, obligations: _ } = self .fcx .probe_instantiate_query_response( @@ -1113,7 +1149,6 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { }) }) }) - .next() } /// For each type `T` in the step list, this attempts to find a method where @@ -1123,7 +1158,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { /// to transparently pass `&mut` pointers, in particular, without consuming /// them for their entire lifetime. fn pick_by_value_method( - &mut self, + &self, step: &CandidateStep<'tcx>, self_ty: Ty<'tcx>, unstable_candidates: Option<&mut Vec<(Candidate<'tcx>, Symbol)>>, @@ -1151,7 +1186,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { } fn pick_autorefd_method( - &mut self, + &self, step: &CandidateStep<'tcx>, self_ty: Ty<'tcx>, mutbl: hir::Mutability, @@ -1177,7 +1212,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { /// special case for this is because going from `*mut T` to `*const T` with autoderefs and /// autorefs would require dereferencing the pointer, which is not safe. fn pick_const_ptr_method( - &mut self, + &self, step: &CandidateStep<'tcx>, self_ty: Ty<'tcx>, unstable_candidates: Option<&mut Vec<(Candidate<'tcx>, Symbol)>>, @@ -1202,7 +1237,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { }) } - fn pick_method_with_unstable(&mut self, self_ty: Ty<'tcx>) -> Option<PickResult<'tcx>> { + fn pick_method_with_unstable(&self, self_ty: Ty<'tcx>) -> Option<PickResult<'tcx>> { debug!("pick_method_with_unstable(self_ty={})", self.ty_to_string(self_ty)); let mut possibly_unsatisfied_predicates = Vec::new(); @@ -1213,7 +1248,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { debug!("searching {} candidates", kind); let res = self.consider_candidates( self_ty, - candidates.iter(), + candidates, &mut possibly_unsatisfied_predicates, Some(&mut vec![]), ); @@ -1222,21 +1257,27 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { } } - debug!("searching unstable candidates"); - let res = self.consider_candidates( - self_ty, - self.inherent_candidates.iter().chain(&self.extension_candidates), - &mut possibly_unsatisfied_predicates, - None, - ); - if res.is_none() { - self.unsatisfied_predicates.extend(possibly_unsatisfied_predicates); + for (kind, candidates) in + &[("inherent", &self.inherent_candidates), ("extension", &self.extension_candidates)] + { + debug!("searching unstable {kind} candidates"); + let res = self.consider_candidates( + self_ty, + candidates, + &mut possibly_unsatisfied_predicates, + None, + ); + if res.is_some() { + return res; + } } - res + + self.unsatisfied_predicates.borrow_mut().extend(possibly_unsatisfied_predicates); + None } fn pick_method( - &mut self, + &self, self_ty: Ty<'tcx>, mut unstable_candidates: Option<&mut Vec<(Candidate<'tcx>, Symbol)>>, ) -> Option<PickResult<'tcx>> { @@ -1254,7 +1295,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { debug!("searching {} candidates", kind); let res = self.consider_candidates( self_ty, - candidates.iter(), + candidates, &mut possibly_unsatisfied_predicates, unstable_candidates.as_deref_mut(), ); @@ -1266,28 +1307,24 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { // `pick_method` may be called twice for the same self_ty if no stable methods // match. Only extend once. if unstable_candidates.is_some() { - self.unsatisfied_predicates.extend(possibly_unsatisfied_predicates); + self.unsatisfied_predicates.borrow_mut().extend(possibly_unsatisfied_predicates); } None } - fn consider_candidates<'b, ProbesIter>( + fn consider_candidates( &self, self_ty: Ty<'tcx>, - probes: ProbesIter, + candidates: &[Candidate<'tcx>], possibly_unsatisfied_predicates: &mut Vec<( ty::Predicate<'tcx>, Option<ty::Predicate<'tcx>>, Option<ObligationCause<'tcx>>, )>, mut unstable_candidates: Option<&mut Vec<(Candidate<'tcx>, Symbol)>>, - ) -> Option<PickResult<'tcx>> - where - ProbesIter: Iterator<Item = &'b Candidate<'tcx>> + Clone, - 'tcx: 'b, - { - let mut applicable_candidates: Vec<_> = probes - .clone() + ) -> Option<PickResult<'tcx>> { + let mut applicable_candidates: Vec<_> = candidates + .iter() .map(|probe| { (probe, self.consider_probe(self_ty, probe, possibly_unsatisfied_predicates)) }) @@ -1305,11 +1342,11 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { } if let Some(uc) = &mut unstable_candidates { - applicable_candidates.retain(|&(p, _)| { + applicable_candidates.retain(|&(candidate, _)| { if let stability::EvalResult::Deny { feature, .. } = - self.tcx.eval_stability(p.item.def_id, None, self.span, None) + self.tcx.eval_stability(candidate.item.def_id, None, self.span, None) { - uc.push((p.clone(), feature)); + uc.push((candidate.clone(), feature)); return false; } true @@ -1317,7 +1354,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { } if applicable_candidates.len() > 1 { - let sources = probes.map(|p| self.candidate_source(p, self_ty)).collect(); + let sources = candidates.iter().map(|p| self.candidate_source(p, self_ty)).collect(); return Some(Err(MethodError::Ambiguity(sources))); } @@ -1505,7 +1542,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { let InferOk { value: normalized_xform_ret_ty, obligations: normalization_obligations, - } = self.fcx.at(&cause, self.param_env).normalize(probe.xform_ret_ty); + } = self.fcx.at(&cause, self.param_env).normalize(xform_ret_ty); xform_ret_ty = normalized_xform_ret_ty; debug!("xform_ret_ty after normalization: {:?}", xform_ret_ty); @@ -1519,7 +1556,23 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { // Convert the bounds into obligations. let impl_obligations = traits::predicates_for_generics( - move |_, _| cause.clone(), + |_idx, span| { + let misc = traits::ObligationCause::misc(span, self.body_id); + let parent_trait_pred = ty::Binder::dummy(ty::TraitPredicate { + trait_ref: ty::TraitRef::from_method(self.tcx, impl_def_id, substs), + constness: ty::BoundConstness::NotConst, + polarity: ty::ImplPolarity::Positive, + }); + misc.derived_cause(parent_trait_pred, |derived| { + traits::ImplDerivedObligation(Box::new( + traits::ImplDerivedObligationCause { + derived, + impl_def_id, + span, + }, + )) + }) + }, self.param_env, impl_bounds, ); @@ -1534,11 +1587,29 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { let o = self.resolve_vars_if_possible(o); if !self.predicate_may_hold(&o) { result = ProbeResult::NoMatch; - possibly_unsatisfied_predicates.push(( - o.predicate, - None, - Some(o.cause), - )); + let parent_o = o.clone(); + let implied_obligations = + traits::elaborate_obligations(self.tcx, vec![o]); + for o in implied_obligations { + let parent = if o == parent_o { + None + } else { + if o.predicate.to_opt_poly_trait_pred().map(|p| p.def_id()) + == self.tcx.lang_items().sized_trait() + { + // We don't care to talk about implicit `Sized` bounds. + continue; + } + Some(parent_o.predicate) + }; + if !self.predicate_may_hold(&o) { + possibly_unsatisfied_predicates.push(( + o.predicate, + parent, + Some(o.cause), + )); + } + } } } } @@ -1562,7 +1633,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { ty::Binder::dummy(trait_ref).without_const().to_predicate(self.tcx); parent_pred = Some(predicate); let obligation = - traits::Obligation::new(self.tcx, cause, self.param_env, predicate); + traits::Obligation::new(self.tcx, cause.clone(), self.param_env, predicate); if !self.predicate_may_hold(&obligation) { result = ProbeResult::NoMatch; if self.probe(|_| { @@ -1621,22 +1692,48 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { } } - if let ProbeResult::Match = result { - if let (Some(return_ty), Some(xform_ret_ty)) = (self.return_type, xform_ret_ty) { - let xform_ret_ty = self.resolve_vars_if_possible(xform_ret_ty); - debug!( - "comparing return_ty {:?} with xform ret ty {:?}", - return_ty, probe.xform_ret_ty - ); - if self - .at(&ObligationCause::dummy(), self.param_env) - .define_opaque_types(false) - .sup(return_ty, xform_ret_ty) - .is_err() - { - return ProbeResult::BadReturnType; + if let ProbeResult::Match = result + && let Some(return_ty) = self.return_type + && let Some(mut xform_ret_ty) = xform_ret_ty + { + // `xform_ret_ty` has only been normalized for `InherentImplCandidate`. + // We don't normalize the other candidates for perf/backwards-compat reasons... + // but `self.return_type` is only set on the diagnostic-path, so we + // should be okay doing it here. + if !matches!(probe.kind, InherentImplCandidate(..)) { + let InferOk { + value: normalized_xform_ret_ty, + obligations: normalization_obligations, + } = self.fcx.at(&cause, self.param_env).normalize(xform_ret_ty); + xform_ret_ty = normalized_xform_ret_ty; + debug!("xform_ret_ty after normalization: {:?}", xform_ret_ty); + // Evaluate those obligations to see if they might possibly hold. + for o in normalization_obligations { + let o = self.resolve_vars_if_possible(o); + if !self.predicate_may_hold(&o) { + result = ProbeResult::NoMatch; + possibly_unsatisfied_predicates.push(( + o.predicate, + None, + Some(o.cause), + )); + } } } + + debug!( + "comparing return_ty {:?} with xform ret ty {:?}", + return_ty, xform_ret_ty + ); + if let ProbeResult::Match = result + && self + .at(&ObligationCause::dummy(), self.param_env) + .define_opaque_types(false) + .sup(return_ty, xform_ret_ty) + .is_err() + { + result = ProbeResult::BadReturnType; + } } result @@ -1650,7 +1747,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { /// probe. This will result in a pending obligation so when more type-info is available we can /// make the final decision. /// - /// Example (`src/test/ui/method-two-trait-defer-resolution-1.rs`): + /// Example (`tests/ui/method-two-trait-defer-resolution-1.rs`): /// /// ```ignore (illustrative) /// trait Foo { ... } @@ -1701,7 +1798,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { self.mode, self.method_name, self.return_type, - self.orig_steps_var_values.clone(), + &self.orig_steps_var_values, steps, self.scope_expr_id, ); @@ -1763,8 +1860,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { // -- but this could be overcome. } - fn record_static_candidate(&mut self, source: CandidateSource) { - self.static_candidates.push(source); + fn record_static_candidate(&self, source: CandidateSource) { + self.static_candidates.borrow_mut().push(source); } #[instrument(level = "debug", skip(self))] |