diff --git a/compiler/rustc_borrowck/src/dataflow.rs b/compiler/rustc_borrowck/src/dataflow.rs index 57db2e9fb574d..d3f6c01ab8c3a 100644 --- a/compiler/rustc_borrowck/src/dataflow.rs +++ b/compiler/rustc_borrowck/src/dataflow.rs @@ -1,7 +1,6 @@ use std::fmt; use rustc_data_structures::fx::FxIndexMap; -use rustc_data_structures::graph; use rustc_index::bit_set::{DenseBitSet, MixedBitSet}; use rustc_middle::mir::{ self, BasicBlock, Body, CallReturnPlaces, Location, Place, TerminatorEdges, @@ -317,9 +316,8 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> { loans_out_of_scope_at_location: FxIndexMap::default(), }; for (loan_idx, loan_data) in borrow_set.iter_enumerated() { - let issuing_region = loan_data.region; let loan_issued_at = loan_data.reserve_location; - prec.precompute_loans_out_of_scope(loan_idx, issuing_region, loan_issued_at); + prec.precompute_loans_out_of_scope(loan_idx, loan_issued_at); } prec.loans_out_of_scope_at_location @@ -328,45 +326,7 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> { /// Loans are in scope while they are live: whether they are contained within any live region. /// In the location-insensitive analysis, a loan will be contained in a region if the issuing /// region can reach it in the subset graph. So this is a reachability problem. - fn precompute_loans_out_of_scope( - &mut self, - loan_idx: BorrowIndex, - issuing_region: RegionVid, - loan_issued_at: Location, - ) { - let sccs = self.regioncx.constraint_sccs(); - let universal_regions = self.regioncx.universal_regions(); - - // The loop below was useful for the location-insensitive analysis but shouldn't be - // impactful in the location-sensitive case. It seems that it does, however, as without it a - // handful of tests fail. That likely means some liveness or outlives data related to choice - // regions is missing - // FIXME: investigate the impact of loans traversing applied member constraints and why some - // tests fail otherwise. - // - // We first handle the cases where the loan doesn't go out of scope, depending on the - // issuing region's successors. - for successor in graph::depth_first_search(&self.regioncx.region_graph(), issuing_region) { - // Via applied member constraints - // - // The issuing region can flow into the choice regions, and they are either: - // - placeholders or free regions themselves, - // - or also transitively outlive a free region. - // - // That is to say, if there are applied member constraints here, the loan escapes the - // function and cannot go out of scope. We could early return here. - // - // For additional insurance via fuzzing and crater, we verify that the constraint's min - // choice indeed escapes the function. In the future, we could e.g. turn this check into - // a debug assert and early return as an optimization. - let scc = sccs.scc(successor); - for constraint in self.regioncx.applied_member_constraints(scc) { - if universal_regions.is_universal_region(constraint.min_choice) { - return; - } - } - } - + fn precompute_loans_out_of_scope(&mut self, loan_idx: BorrowIndex, loan_issued_at: Location) { let first_block = loan_issued_at.block; let first_bb_data = &self.body.basic_blocks[first_block]; diff --git a/compiler/rustc_borrowck/src/diagnostics/opaque_types.rs b/compiler/rustc_borrowck/src/diagnostics/opaque_types.rs index 83fe4a9f98f49..e16af988f6987 100644 --- a/compiler/rustc_borrowck/src/diagnostics/opaque_types.rs +++ b/compiler/rustc_borrowck/src/diagnostics/opaque_types.rs @@ -13,6 +13,8 @@ use rustc_middle::mir::{self, ConstraintCategory, Location}; use rustc_middle::ty::{ self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor, }; +use rustc_span::Span; +use rustc_trait_selection::error_reporting::infer::region::unexpected_hidden_region_diagnostic; use rustc_trait_selection::errors::impl_trait_overcapture_suggestion; use crate::MirBorrowckCtxt; @@ -26,13 +28,61 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { if errors.is_empty() { return; } + + let infcx = self.infcx; let mut guar = None; + let mut last_unexpected_hidden_region: Option<(Span, Ty<'_>, ty::OpaqueTypeKey<'tcx>)> = + None; for error in errors { guar = Some(match error { - DeferredOpaqueTypeError::InvalidOpaqueTypeArgs(err) => err.report(self.infcx), + DeferredOpaqueTypeError::InvalidOpaqueTypeArgs(err) => err.report(infcx), DeferredOpaqueTypeError::LifetimeMismatchOpaqueParam(err) => { - self.infcx.dcx().emit_err(err) + infcx.dcx().emit_err(err) + } + DeferredOpaqueTypeError::UnexpectedHiddenRegion { + opaque_type_key, + hidden_type, + member_region, + } => { + let named_ty = + self.regioncx.name_regions_for_member_constraint(infcx.tcx, hidden_type.ty); + let named_key = self + .regioncx + .name_regions_for_member_constraint(infcx.tcx, opaque_type_key); + let named_region = + self.regioncx.name_regions_for_member_constraint(infcx.tcx, member_region); + let diag = unexpected_hidden_region_diagnostic( + infcx, + self.mir_def_id(), + hidden_type.span, + named_ty, + named_region, + named_key, + ); + if last_unexpected_hidden_region + != Some((hidden_type.span, named_ty, named_key)) + { + last_unexpected_hidden_region = + Some((hidden_type.span, named_ty, named_key)); + diag.emit() + } else { + diag.delay_as_bug() + } } + DeferredOpaqueTypeError::NonDefiningUseInDefiningScope { + span, + opaque_type_key, + } => infcx.dcx().span_err( + span, + format!( + "non-defining use of `{}` in the defining scope", + Ty::new_opaque( + infcx.tcx, + opaque_type_key.def_id.to_def_id(), + opaque_type_key.args + ) + ), + ), }); } let guar = guar.unwrap(); diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs index 2b74f1a48f731..127a9da39c2da 100644 --- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs @@ -23,7 +23,6 @@ use rustc_trait_selection::error_reporting::infer::nice_region_error::{ self, HirTraitObjectVisitor, NiceRegionError, TraitObjectVisitor, find_anon_type, find_param_with_region, suggest_adding_lifetime_params, }; -use rustc_trait_selection::error_reporting::infer::region::unexpected_hidden_region_diagnostic; use rustc_trait_selection::infer::InferCtxtExt; use rustc_trait_selection::traits::{Obligation, ObligationCtxt}; use tracing::{debug, instrument, trace}; @@ -105,18 +104,6 @@ pub(crate) enum RegionErrorKind<'tcx> { /// A generic bound failure for a type test (`T: 'a`). TypeTestError { type_test: TypeTest<'tcx> }, - /// An unexpected hidden region for an opaque type. - UnexpectedHiddenRegion { - /// The span for the member constraint. - span: Span, - /// The hidden type. - hidden_ty: Ty<'tcx>, - /// The opaque type. - key: ty::OpaqueTypeKey<'tcx>, - /// The unexpected region. - member_region: ty::Region<'tcx>, - }, - /// Higher-ranked subtyping error. BoundUniversalRegionError { /// The placeholder free region. @@ -307,11 +294,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { pub(crate) fn report_region_errors(&mut self, nll_errors: RegionErrors<'tcx>) { // Iterate through all the errors, producing a diagnostic for each one. The diagnostics are // buffered in the `MirBorrowckCtxt`. - let mut outlives_suggestion = OutlivesSuggestionBuilder::default(); - let mut last_unexpected_hidden_region: Option<(Span, Ty<'_>, ty::OpaqueTypeKey<'tcx>)> = - None; - for (nll_error, _) in nll_errors.into_iter() { match nll_error { RegionErrorKind::TypeTestError { type_test } => { @@ -362,30 +345,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { } } - RegionErrorKind::UnexpectedHiddenRegion { span, hidden_ty, key, member_region } => { - let named_ty = - self.regioncx.name_regions_for_member_constraint(self.infcx.tcx, hidden_ty); - let named_key = - self.regioncx.name_regions_for_member_constraint(self.infcx.tcx, key); - let named_region = self - .regioncx - .name_regions_for_member_constraint(self.infcx.tcx, member_region); - let diag = unexpected_hidden_region_diagnostic( - self.infcx, - self.mir_def_id(), - span, - named_ty, - named_region, - named_key, - ); - if last_unexpected_hidden_region != Some((span, named_ty, named_key)) { - self.buffer_error(diag); - last_unexpected_hidden_region = Some((span, named_ty, named_key)); - } else { - diag.delay_as_bug(); - } - } - RegionErrorKind::BoundUniversalRegionError { longer_fr, placeholder, diff --git a/compiler/rustc_borrowck/src/handle_placeholders.rs b/compiler/rustc_borrowck/src/handle_placeholders.rs index 34599ac55b85a..65ed9c04ea507 100644 --- a/compiler/rustc_borrowck/src/handle_placeholders.rs +++ b/compiler/rustc_borrowck/src/handle_placeholders.rs @@ -15,7 +15,6 @@ use tracing::debug; use crate::constraints::{ConstraintSccIndex, OutlivesConstraintSet}; use crate::consumers::OutlivesConstraint; use crate::diagnostics::UniverseInfo; -use crate::member_constraints::MemberConstraintSet; use crate::region_infer::values::{LivenessValues, PlaceholderIndices}; use crate::region_infer::{ConstraintSccs, RegionDefinition, Representative, TypeTest}; use crate::ty::VarianceDiagInfo; @@ -30,7 +29,6 @@ pub(crate) struct LoweredConstraints<'tcx> { pub(crate) constraint_sccs: Sccs, pub(crate) definitions: Frozen>>, pub(crate) scc_annotations: IndexVec, - pub(crate) member_constraints: MemberConstraintSet<'tcx, RegionVid>, pub(crate) outlives_constraints: Frozen>, pub(crate) type_tests: Vec>, pub(crate) liveness_constraints: LivenessValues, @@ -143,9 +141,10 @@ impl scc::Annotation for RegionTracker { /// Determines if the region variable definitions contain /// placeholders, and compute them for later use. -fn region_definitions<'tcx>( - universal_regions: &UniversalRegions<'tcx>, +// FIXME: This is also used by opaque type handling. Move it to a separate file. +pub(super) fn region_definitions<'tcx>( infcx: &BorrowckInferCtxt<'tcx>, + universal_regions: &UniversalRegions<'tcx>, ) -> (Frozen>>, bool) { let var_infos = infcx.get_region_var_infos(); // Create a RegionDefinition for each inference variable. This happens here because @@ -209,14 +208,13 @@ pub(crate) fn compute_sccs_applying_placeholder_outlives_constraints<'tcx>( infcx: &BorrowckInferCtxt<'tcx>, ) -> LoweredConstraints<'tcx> { let universal_regions = &universal_region_relations.universal_regions; - let (definitions, has_placeholders) = region_definitions(universal_regions, infcx); + let (definitions, has_placeholders) = region_definitions(infcx, universal_regions); let MirTypeckRegionConstraints { placeholder_indices, placeholder_index_to_region: _, liveness_constraints, mut outlives_constraints, - member_constraints, universe_causes, type_tests, } = constraints; @@ -242,7 +240,6 @@ pub(crate) fn compute_sccs_applying_placeholder_outlives_constraints<'tcx>( return LoweredConstraints { type_tests, - member_constraints, constraint_sccs, scc_annotations: scc_annotations.scc_to_annotation, definitions, @@ -279,7 +276,6 @@ pub(crate) fn compute_sccs_applying_placeholder_outlives_constraints<'tcx>( constraint_sccs, definitions, scc_annotations, - member_constraints, outlives_constraints: Frozen::freeze(outlives_constraints), type_tests, liveness_constraints, diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs index d76d6a04e6e03..a081e0dee5d43 100644 --- a/compiler/rustc_borrowck/src/lib.rs +++ b/compiler/rustc_borrowck/src/lib.rs @@ -78,7 +78,6 @@ mod dataflow; mod def_use; mod diagnostics; mod handle_placeholders; -mod member_constraints; mod nll; mod path_utils; mod place_ext; @@ -335,9 +334,10 @@ fn do_mir_borrowck<'tcx>( // Run the MIR type-checker. let MirTypeckResults { - constraints, + mut constraints, universal_region_relations, - opaque_type_values, + region_bound_pairs, + known_type_outlives_obligations, polonius_context, } = type_check::type_check( root_cx, @@ -352,6 +352,17 @@ fn do_mir_borrowck<'tcx>( Rc::clone(&location_map), ); + let opaque_type_errors = region_infer::opaque_types::handle_opaque_type_uses( + root_cx, + &infcx, + &body, + &universal_region_relations, + ®ion_bound_pairs, + &known_type_outlives_obligations, + &location_map, + &mut constraints, + ); + // Compute non-lexical lifetimes using the constraints computed // by typechecking the MIR body. let nll::NllOutput { @@ -375,8 +386,6 @@ fn do_mir_borrowck<'tcx>( polonius_context, ); - let opaque_type_errors = regioncx.infer_opaque_types(root_cx, &infcx, opaque_type_values); - // Dump MIR results into a file, if that is enabled. This lets us // write unit-tests, as well as helping with debugging. nll::dump_nll_mir(&infcx, body, ®ioncx, &opt_closure_req, &borrow_set); diff --git a/compiler/rustc_borrowck/src/member_constraints.rs b/compiler/rustc_borrowck/src/member_constraints.rs deleted file mode 100644 index bdd0f6fe11e0f..0000000000000 --- a/compiler/rustc_borrowck/src/member_constraints.rs +++ /dev/null @@ -1,226 +0,0 @@ -use std::hash::Hash; -use std::ops::Index; - -use rustc_data_structures::fx::FxIndexMap; -use rustc_index::{IndexSlice, IndexVec}; -use rustc_middle::ty::{self, Ty}; -use rustc_span::Span; -use tracing::instrument; - -/// Compactly stores a set of `R0 member of [R1...Rn]` constraints, -/// indexed by the region `R0`. -#[derive(Debug)] -pub(crate) struct MemberConstraintSet<'tcx, R> -where - R: Copy + Eq, -{ - /// Stores the first "member" constraint for a given `R0`. This is an - /// index into the `constraints` vector below. - first_constraints: FxIndexMap, - - /// Stores the data about each `R0 member of [R1..Rn]` constraint. - /// These are organized into a linked list, so each constraint - /// contains the index of the next constraint with the same `R0`. - constraints: IndexVec>, - - /// Stores the `R1..Rn` regions for *all* sets. For any given - /// constraint, we keep two indices so that we can pull out a - /// slice. - choice_regions: Vec, -} - -/// Represents a `R0 member of [R1..Rn]` constraint -#[derive(Debug)] -pub(crate) struct MemberConstraint<'tcx> { - next_constraint: Option, - - /// The span where the hidden type was instantiated. - pub(crate) definition_span: Span, - - /// The hidden type in which `R0` appears. (Used in error reporting.) - pub(crate) hidden_ty: Ty<'tcx>, - - pub(crate) key: ty::OpaqueTypeKey<'tcx>, - - /// The region `R0`. - pub(crate) member_region_vid: ty::RegionVid, - - /// Index of `R1` in `choice_regions` vector from `MemberConstraintSet`. - start_index: usize, - - /// Index of `Rn` in `choice_regions` vector from `MemberConstraintSet`. - end_index: usize, -} - -rustc_index::newtype_index! { - #[debug_format = "MemberConstraintIndex({})"] - pub(crate) struct NllMemberConstraintIndex {} -} - -impl Default for MemberConstraintSet<'_, ty::RegionVid> { - fn default() -> Self { - Self { - first_constraints: Default::default(), - constraints: Default::default(), - choice_regions: Default::default(), - } - } -} - -impl<'tcx> MemberConstraintSet<'tcx, ty::RegionVid> { - pub(crate) fn is_empty(&self) -> bool { - self.constraints.is_empty() - } - - /// Pushes a member constraint into the set. - #[instrument(level = "debug", skip(self))] - pub(crate) fn add_member_constraint( - &mut self, - key: ty::OpaqueTypeKey<'tcx>, - hidden_ty: Ty<'tcx>, - definition_span: Span, - member_region_vid: ty::RegionVid, - choice_regions: &[ty::RegionVid], - ) { - let next_constraint = self.first_constraints.get(&member_region_vid).cloned(); - let start_index = self.choice_regions.len(); - self.choice_regions.extend(choice_regions); - let end_index = self.choice_regions.len(); - let constraint_index = self.constraints.push(MemberConstraint { - next_constraint, - member_region_vid, - definition_span, - hidden_ty, - key, - start_index, - end_index, - }); - self.first_constraints.insert(member_region_vid, constraint_index); - } -} - -impl<'tcx, R1> MemberConstraintSet<'tcx, R1> -where - R1: Copy + Hash + Eq, -{ - /// Remap the "member region" key using `map_fn`, producing a new - /// member constraint set. This is used in the NLL code to map from - /// the original `RegionVid` to an scc index. In some cases, we - /// may have multiple `R1` values mapping to the same `R2` key -- that - /// is ok, the two sets will be merged. - pub(crate) fn into_mapped( - self, - mut map_fn: impl FnMut(R1) -> R2, - ) -> MemberConstraintSet<'tcx, R2> - where - R2: Copy + Hash + Eq, - { - // We can re-use most of the original data, just tweaking the - // linked list links a bit. - // - // For example if we had two keys `Ra` and `Rb` that both now - // wind up mapped to the same key `S`, we would append the - // linked list for `Ra` onto the end of the linked list for - // `Rb` (or vice versa) -- this basically just requires - // rewriting the final link from one list to point at the other - // other (see `append_list`). - - let MemberConstraintSet { first_constraints, mut constraints, choice_regions } = self; - - let mut first_constraints2 = FxIndexMap::default(); - first_constraints2.reserve(first_constraints.len()); - - for (r1, start1) in first_constraints { - let r2 = map_fn(r1); - if let Some(&start2) = first_constraints2.get(&r2) { - append_list(&mut constraints, start1, start2); - } - first_constraints2.insert(r2, start1); - } - - MemberConstraintSet { first_constraints: first_constraints2, constraints, choice_regions } - } -} - -impl<'tcx, R> MemberConstraintSet<'tcx, R> -where - R: Copy + Hash + Eq, -{ - pub(crate) fn all_indices(&self) -> impl Iterator { - self.constraints.indices() - } - - /// Iterate down the constraint indices associated with a given - /// peek-region. You can then use `choice_regions` and other - /// methods to access data. - pub(crate) fn indices( - &self, - member_region_vid: R, - ) -> impl Iterator { - let mut next = self.first_constraints.get(&member_region_vid).cloned(); - std::iter::from_fn(move || -> Option { - if let Some(current) = next { - next = self.constraints[current].next_constraint; - Some(current) - } else { - None - } - }) - } - - /// Returns the "choice regions" for a given member - /// constraint. This is the `R1..Rn` from a constraint like: - /// - /// ```text - /// R0 member of [R1..Rn] - /// ``` - pub(crate) fn choice_regions(&self, pci: NllMemberConstraintIndex) -> &[ty::RegionVid] { - let MemberConstraint { start_index, end_index, .. } = &self.constraints[pci]; - &self.choice_regions[*start_index..*end_index] - } -} - -impl<'tcx, R> Index for MemberConstraintSet<'tcx, R> -where - R: Copy + Eq, -{ - type Output = MemberConstraint<'tcx>; - - fn index(&self, i: NllMemberConstraintIndex) -> &MemberConstraint<'tcx> { - &self.constraints[i] - } -} - -/// Given a linked list starting at `source_list` and another linked -/// list starting at `target_list`, modify `target_list` so that it is -/// followed by `source_list`. -/// -/// Before: -/// -/// ```text -/// target_list: A -> B -> C -> (None) -/// source_list: D -> E -> F -> (None) -/// ``` -/// -/// After: -/// -/// ```text -/// target_list: A -> B -> C -> D -> E -> F -> (None) -/// ``` -fn append_list( - constraints: &mut IndexSlice>, - target_list: NllMemberConstraintIndex, - source_list: NllMemberConstraintIndex, -) { - let mut p = target_list; - loop { - let r = &mut constraints[p]; - match r.next_constraint { - Some(q) => p = q, - None => { - r.next_constraint = Some(source_list); - return; - } - } - } -} diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs index b0c31ac960109..d6d6b8a6bf2f7 100644 --- a/compiler/rustc_borrowck/src/region_infer/mod.rs +++ b/compiler/rustc_borrowck/src/region_infer/mod.rs @@ -1,8 +1,6 @@ -use std::cell::OnceCell; use std::collections::VecDeque; use std::rc::Rc; -use rustc_data_structures::binary_search_util; use rustc_data_structures::frozen::Frozen; use rustc_data_structures::fx::{FxIndexMap, FxIndexSet}; use rustc_data_structures::graph::scc::{self, Sccs}; @@ -24,15 +22,13 @@ use rustc_span::hygiene::DesugaringKind; use rustc_span::{DUMMY_SP, Span}; use tracing::{Level, debug, enabled, instrument, trace}; -use crate::constraints::graph::{self, NormalConstraintGraph, RegionGraph}; +use crate::constraints::graph::NormalConstraintGraph; use crate::constraints::{ConstraintSccIndex, OutlivesConstraint, OutlivesConstraintSet}; use crate::dataflow::BorrowIndex; use crate::diagnostics::{RegionErrorKind, RegionErrors, UniverseInfo}; use crate::handle_placeholders::{LoweredConstraints, RegionTracker}; -use crate::member_constraints::{MemberConstraintSet, NllMemberConstraintIndex}; use crate::polonius::LiveLoans; use crate::polonius::legacy::PoloniusOutput; -use crate::region_infer::reverse_sccs::ReverseSccGraph; use crate::region_infer::values::{LivenessValues, RegionElement, RegionValues, ToElementIndex}; use crate::type_check::Locations; use crate::type_check::free_region_relations::UniversalRegionRelations; @@ -120,20 +116,6 @@ pub struct RegionInferenceContext<'tcx> { scc_annotations: IndexVec, - /// Reverse of the SCC constraint graph -- i.e., an edge `A -> B` exists if - /// `B: A`. This is used to compute the universal regions that are required - /// to outlive a given SCC. - rev_scc_graph: OnceCell, - - /// The "R0 member of [R1..Rn]" constraints, indexed by SCC. - member_constraints: Rc>, - - /// Records the member constraints that we applied to each scc. - /// This is useful for error reporting. Once constraint - /// propagation is done, this vector is sorted according to - /// `member_region_scc`. - member_constraints_applied: Vec, - /// Map universe indexes to information on why we created it. universe_causes: FxIndexMap>, @@ -150,32 +132,6 @@ pub struct RegionInferenceContext<'tcx> { universal_region_relations: Frozen>, } -/// Each time that `apply_member_constraint` is successful, it appends -/// one of these structs to the `member_constraints_applied` field. -/// This is used in error reporting to trace out what happened. -/// -/// The way that `apply_member_constraint` works is that it effectively -/// adds a new lower bound to the SCC it is analyzing: so you wind up -/// with `'R: 'O` where `'R` is the pick-region and `'O` is the -/// minimal viable option. -#[derive(Debug)] -pub(crate) struct AppliedMemberConstraint { - /// The SCC that was affected. (The "member region".) - /// - /// The vector if `AppliedMemberConstraint` elements is kept sorted - /// by this field. - pub(crate) member_region_scc: ConstraintSccIndex, - - /// The "best option" that `apply_member_constraint` found -- this was - /// added as an "ad-hoc" lower-bound to `member_region_scc`. - pub(crate) min_choice: ty::RegionVid, - - /// The "member constraint index" -- we can find out details about - /// the constraint from - /// `set.member_constraints[member_constraint_index]`. - pub(crate) member_constraint_index: NllMemberConstraintIndex, -} - #[derive(Debug)] pub(crate) struct RegionDefinition<'tcx> { /// What kind of variable is this -- a free region? existential @@ -268,7 +224,6 @@ enum Trace<'a, 'tcx> { StartRegion, FromGraph(&'a OutlivesConstraint<'tcx>), FromStatic(RegionVid), - FromMember(RegionVid, RegionVid, Span), NotVisited, } @@ -363,7 +318,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { liveness_constraints, universe_causes, placeholder_indices, - member_constraints, } = lowered_constraints; debug!("universal_regions: {:#?}", universal_region_relations.universal_regions); @@ -385,9 +339,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { scc_values.merge_liveness(scc, region, &liveness_constraints); } - let member_constraints = - Rc::new(member_constraints.into_mapped(|r| constraint_sccs.scc(r))); - let mut result = Self { definitions, liveness_constraints, @@ -395,9 +346,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { constraint_graph, constraint_sccs, scc_annotations, - rev_scc_graph: OnceCell::new(), - member_constraints, - member_constraints_applied: Vec::new(), universe_causes, scc_values, type_tests, @@ -550,19 +498,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { self.scc_values.placeholders_contained_in(scc) } - /// Once region solving has completed, this function will return the member constraints that - /// were applied to the value of a given SCC `scc`. See `AppliedMemberConstraint`. - pub(crate) fn applied_member_constraints( - &self, - scc: ConstraintSccIndex, - ) -> &[AppliedMemberConstraint] { - binary_search_util::binary_search_slice( - &self.member_constraints_applied, - |applied| applied.member_region_scc, - &scc, - ) - } - /// Performs region inference and report errors if we see any /// unsatisfiable constraints. If this is a closure, returns the /// region requirements to propagate to our creator, if any. @@ -607,12 +542,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { debug!(?errors_buffer); - if errors_buffer.is_empty() { - self.check_member_constraints(infcx, &mut errors_buffer); - } - - debug!(?errors_buffer); - let outlives_requirements = outlives_requirements.unwrap_or_default(); if outlives_requirements.is_empty() { @@ -642,146 +571,15 @@ impl<'tcx> RegionInferenceContext<'tcx> { }); // To propagate constraints, we walk the DAG induced by the - // SCC. For each SCC, we visit its successors and compute + // SCC. For each SCC `A`, we visit its successors and compute // their values, then we union all those values to get our // own. - for scc in self.constraint_sccs.all_sccs() { - self.compute_value_for_scc(scc); - } - - // Sort the applied member constraints so we can binary search - // through them later. - self.member_constraints_applied.sort_by_key(|applied| applied.member_region_scc); - } - - /// Computes the value of the SCC `scc_a`, which has not yet been - /// computed, by unioning the values of its successors. - /// Assumes that all successors have been computed already - /// (which is assured by iterating over SCCs in dependency order). - #[instrument(skip(self), level = "debug")] - fn compute_value_for_scc(&mut self, scc_a: ConstraintSccIndex) { - // Walk each SCC `B` such that `A: B`... - for &scc_b in self.constraint_sccs.successors(scc_a) { - debug!(?scc_b); - self.scc_values.add_region(scc_a, scc_b); - } - - // Now take member constraints into account. - let member_constraints = Rc::clone(&self.member_constraints); - for m_c_i in member_constraints.indices(scc_a) { - self.apply_member_constraint(scc_a, m_c_i, member_constraints.choice_regions(m_c_i)); - } - - debug!(value = ?self.scc_values.region_value_str(scc_a)); - } - - /// Invoked for each `R0 member of [R1..Rn]` constraint. - /// - /// `scc` is the SCC containing R0, and `choice_regions` are the - /// `R1..Rn` regions -- they are always known to be universal - /// regions (and if that's not true, we just don't attempt to - /// enforce the constraint). - /// - /// The current value of `scc` at the time the method is invoked - /// is considered a *lower bound*. If possible, we will modify - /// the constraint to set it equal to one of the option regions. - /// If we make any changes, returns true, else false. - /// - /// This function only adds the member constraints to the region graph, - /// it does not check them. They are later checked in - /// `check_member_constraints` after the region graph has been computed. - #[instrument(skip(self, member_constraint_index), level = "debug")] - fn apply_member_constraint( - &mut self, - scc: ConstraintSccIndex, - member_constraint_index: NllMemberConstraintIndex, - choice_regions: &[ty::RegionVid], - ) { - // Create a mutable vector of the options. We'll try to winnow - // them down. - let mut choice_regions: Vec = choice_regions.to_vec(); - - // Convert to the SCC representative: sometimes we have inference - // variables in the member constraint that wind up equated with - // universal regions. The scc representative is the minimal numbered - // one from the corresponding scc so it will be the universal region - // if one exists. - for c_r in &mut choice_regions { - let scc = self.constraint_sccs.scc(*c_r); - *c_r = self.scc_representative(scc); - } - - // If the member region lives in a higher universe, we currently choose - // the most conservative option by leaving it unchanged. - if !self.max_nameable_universe(scc).is_root() { - return; - } - - // The existing value for `scc` is a lower-bound. This will - // consist of some set `{P} + {LB}` of points `{P}` and - // lower-bound free regions `{LB}`. As each choice region `O` - // is a free region, it will outlive the points. But we can - // only consider the option `O` if `O: LB`. - choice_regions.retain(|&o_r| { - self.scc_values - .universal_regions_outlived_by(scc) - .all(|lb| self.universal_region_relations.outlives(o_r, lb)) - }); - debug!(?choice_regions, "after lb"); - - // Now find all the *upper bounds* -- that is, each UB is a - // free region that must outlive the member region `R0` (`UB: - // R0`). Therefore, we need only keep an option `O` if `UB: O` - // for all UB. - let universal_region_relations = &self.universal_region_relations; - for ub in self.reverse_scc_graph().upper_bounds(scc) { - debug!(?ub); - choice_regions.retain(|&o_r| universal_region_relations.outlives(ub, o_r)); - } - debug!(?choice_regions, "after ub"); - - // At this point we can pick any member of `choice_regions` and would like to choose - // it to be a small as possible. To avoid potential non-determinism we will pick the - // smallest such choice. - // - // Because universal regions are only partially ordered (i.e, not every two regions are - // comparable), we will ignore any region that doesn't compare to all others when picking - // the minimum choice. - // - // For example, consider `choice_regions = ['static, 'a, 'b, 'c, 'd, 'e]`, where - // `'static: 'a, 'static: 'b, 'a: 'c, 'b: 'c, 'c: 'd, 'c: 'e`. - // `['d, 'e]` are ignored because they do not compare - the same goes for `['a, 'b]`. - let totally_ordered_subset = choice_regions.iter().copied().filter(|&r1| { - choice_regions.iter().all(|&r2| { - self.universal_region_relations.outlives(r1, r2) - || self.universal_region_relations.outlives(r2, r1) - }) - }); - // Now we're left with `['static, 'c]`. Pick `'c` as the minimum! - let Some(min_choice) = totally_ordered_subset.reduce(|r1, r2| { - let r1_outlives_r2 = self.universal_region_relations.outlives(r1, r2); - let r2_outlives_r1 = self.universal_region_relations.outlives(r2, r1); - match (r1_outlives_r2, r2_outlives_r1) { - (true, true) => r1.min(r2), - (true, false) => r2, - (false, true) => r1, - (false, false) => bug!("incomparable regions in total order"), + for scc_a in self.constraint_sccs.all_sccs() { + // Walk each SCC `B` such that `A: B`... + for &scc_b in self.constraint_sccs.successors(scc_a) { + debug!(?scc_b); + self.scc_values.add_region(scc_a, scc_b); } - }) else { - debug!("no unique minimum choice"); - return; - }; - - // As we require `'scc: 'min_choice`, we have definitely already computed - // its `scc_values` at this point. - let min_choice_scc = self.constraint_sccs.scc(min_choice); - debug!(?min_choice, ?min_choice_scc); - if self.scc_values.add_region(scc, min_choice_scc) { - self.member_constraints_applied.push(AppliedMemberConstraint { - member_region_scc: scc, - min_choice, - member_constraint_index, - }); } } @@ -1544,43 +1342,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { } } - #[instrument(level = "debug", skip(self, infcx, errors_buffer))] - fn check_member_constraints( - &self, - infcx: &InferCtxt<'tcx>, - errors_buffer: &mut RegionErrors<'tcx>, - ) { - let member_constraints = Rc::clone(&self.member_constraints); - for m_c_i in member_constraints.all_indices() { - debug!(?m_c_i); - let m_c = &member_constraints[m_c_i]; - let member_region_vid = m_c.member_region_vid; - debug!( - ?member_region_vid, - value = ?self.region_value_str(member_region_vid), - ); - let choice_regions = member_constraints.choice_regions(m_c_i); - debug!(?choice_regions); - - // Did the member region wind up equal to any of the option regions? - if let Some(o) = - choice_regions.iter().find(|&&o_r| self.eval_equal(o_r, m_c.member_region_vid)) - { - debug!("evaluated as equal to {:?}", o); - continue; - } - - // If not, report an error. - let member_region = ty::Region::new_var(infcx.tcx, member_region_vid); - errors_buffer.push(RegionErrorKind::UnexpectedHiddenRegion { - span: m_c.definition_span, - hidden_ty: m_c.hidden_ty, - key: m_c.key, - member_region, - }); - } - } - /// We have a constraint `fr1: fr2` that is not satisfied, where /// `fr2` represents some universal region. Here, `r` is some /// region where we know that `fr1: r` and this function has the @@ -1704,20 +1465,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { result.push(c); } - Trace::FromMember(sup, sub, span) => { - let c = OutlivesConstraint { - sup, - sub, - locations: Locations::All(span), - span, - category: ConstraintCategory::OpaqueType, - variance_info: ty::VarianceDiagInfo::default(), - from_closure: false, - }; - p = c.sup; - result.push(c); - } - Trace::StartRegion => { result.reverse(); return Some((result, r)); @@ -1764,15 +1511,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { handle_trace(constraint.sub, Trace::FromGraph(constraint)); } } - - // Member constraints can also give rise to `'r: 'x` edges that - // were not part of the graph initially, so watch out for those. - // (But they are extremely rare; this loop is very cold.) - for constraint in self.applied_member_constraints(self.constraint_sccs.scc(r)) { - let sub = constraint.min_choice; - let p_c = &self.member_constraints[constraint.member_constraint_index]; - handle_trace(sub, Trace::FromMember(r, sub, p_c.definition_span)); - } } None @@ -2104,11 +1842,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { &self.constraint_sccs } - /// Access to the region graph, built from the outlives constraints. - pub(crate) fn region_graph(&self) -> RegionGraph<'_, 'tcx, graph::Normal> { - self.constraint_graph.region_graph(&self.constraints, self.universal_regions().fr_static) - } - /// Returns the representative `RegionVid` for a given SCC. /// See `RegionTracker` for how a region variable ID is chosen. /// diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs deleted file mode 100644 index 23c4554aa155f..0000000000000 --- a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs +++ /dev/null @@ -1,299 +0,0 @@ -use rustc_data_structures::fx::FxIndexMap; -use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin}; -use rustc_macros::extension; -use rustc_middle::ty::{ - self, DefiningScopeKind, OpaqueHiddenType, OpaqueTypeKey, Ty, TyCtxt, TypeFoldable, - TypeVisitableExt, fold_regions, -}; -use rustc_span::Span; -use rustc_trait_selection::opaque_types::{ - InvalidOpaqueTypeArgs, check_opaque_type_parameter_valid, -}; -use tracing::{debug, instrument}; - -use super::RegionInferenceContext; -use crate::BorrowCheckRootCtxt; -use crate::session_diagnostics::LifetimeMismatchOpaqueParam; -use crate::universal_regions::RegionClassification; - -pub(crate) enum DeferredOpaqueTypeError<'tcx> { - InvalidOpaqueTypeArgs(InvalidOpaqueTypeArgs<'tcx>), - LifetimeMismatchOpaqueParam(LifetimeMismatchOpaqueParam<'tcx>), -} - -impl<'tcx> RegionInferenceContext<'tcx> { - /// Resolve any opaque types that were encountered while borrow checking - /// this item. This is then used to get the type in the `type_of` query. - /// - /// For example consider `fn f<'a>(x: &'a i32) -> impl Sized + 'a { x }`. - /// This is lowered to give HIR something like - /// - /// type f<'a>::_Return<'_x> = impl Sized + '_x; - /// fn f<'a>(x: &'a i32) -> f<'a>::_Return<'a> { x } - /// - /// When checking the return type record the type from the return and the - /// type used in the return value. In this case they might be `_Return<'1>` - /// and `&'2 i32` respectively. - /// - /// Once we to this method, we have completed region inference and want to - /// call `infer_opaque_definition_from_instantiation` to get the inferred - /// type of `_Return<'_x>`. `infer_opaque_definition_from_instantiation` - /// compares lifetimes directly, so we need to map the inference variables - /// back to concrete lifetimes: `'static`, `ReEarlyParam` or `ReLateParam`. - /// - /// First we map the regions in the generic parameters `_Return<'1>` to - /// their `external_name` giving `_Return<'a>`. This step is a bit involved. - /// See the [rustc-dev-guide chapter] for more info. - /// - /// Then we map all the lifetimes in the concrete type to an equal - /// universal region that occurs in the opaque type's args, in this case - /// this would result in `&'a i32`. We only consider regions in the args - /// in case there is an equal region that does not. For example, this should - /// be allowed: - /// `fn f<'a: 'b, 'b: 'a>(x: *mut &'b i32) -> impl Sized + 'a { x }` - /// - /// This will then allow `infer_opaque_definition_from_instantiation` to - /// determine that `_Return<'_x> = &'_x i32`. - /// - /// There's a slight complication around closures. Given - /// `fn f<'a: 'a>() { || {} }` the closure's type is something like - /// `f::<'a>::{{closure}}`. The region parameter from f is essentially - /// ignored by type checking so ends up being inferred to an empty region. - /// Calling `universal_upper_bound` for such a region gives `fr_fn_body`, - /// which has no `external_name` in which case we use `'{erased}` as the - /// region to pass to `infer_opaque_definition_from_instantiation`. - /// - /// [rustc-dev-guide chapter]: - /// https://rustc-dev-guide.rust-lang.org/opaque-types-region-infer-restrictions.html - #[instrument(level = "debug", skip(self, root_cx, infcx))] - pub(crate) fn infer_opaque_types( - &self, - root_cx: &mut BorrowCheckRootCtxt<'tcx>, - infcx: &InferCtxt<'tcx>, - opaque_ty_decls: FxIndexMap, OpaqueHiddenType<'tcx>>, - ) -> Vec> { - let mut errors = Vec::new(); - let mut decls_modulo_regions: FxIndexMap, (OpaqueTypeKey<'tcx>, Span)> = - FxIndexMap::default(); - - for (opaque_type_key, concrete_type) in opaque_ty_decls { - debug!(?opaque_type_key, ?concrete_type); - - let mut arg_regions: Vec<(ty::RegionVid, ty::Region<'_>)> = - vec![(self.universal_regions().fr_static, infcx.tcx.lifetimes.re_static)]; - - let opaque_type_key = - opaque_type_key.fold_captured_lifetime_args(infcx.tcx, |region| { - // Use the SCC representative instead of directly using `region`. - // See [rustc-dev-guide chapter] § "Strict lifetime equality". - let scc = self.constraint_sccs.scc(region.as_var()); - let vid = self.scc_representative(scc); - let named = match self.definitions[vid].origin { - // Iterate over all universal regions in a consistent order and find the - // *first* equal region. This makes sure that equal lifetimes will have - // the same name and simplifies subsequent handling. - // See [rustc-dev-guide chapter] § "Semantic lifetime equality". - NllRegionVariableOrigin::FreeRegion => self - .universal_regions() - .universal_regions_iter() - .filter(|&ur| { - // See [rustc-dev-guide chapter] § "Closure restrictions". - !matches!( - self.universal_regions().region_classification(ur), - Some(RegionClassification::External) - ) - }) - .find(|&ur| self.universal_region_relations.equal(vid, ur)) - .map(|ur| self.definitions[ur].external_name.unwrap()), - NllRegionVariableOrigin::Placeholder(placeholder) => { - Some(ty::Region::new_placeholder(infcx.tcx, placeholder)) - } - NllRegionVariableOrigin::Existential { .. } => None, - } - .unwrap_or_else(|| { - ty::Region::new_error_with_message( - infcx.tcx, - concrete_type.span, - "opaque type with non-universal region args", - ) - }); - - arg_regions.push((vid, named)); - named - }); - debug!(?opaque_type_key, ?arg_regions); - - let concrete_type = fold_regions(infcx.tcx, concrete_type, |region, _| { - arg_regions - .iter() - .find(|&&(arg_vid, _)| self.eval_equal(region.as_var(), arg_vid)) - .map(|&(_, arg_named)| arg_named) - .unwrap_or(infcx.tcx.lifetimes.re_erased) - }); - debug!(?concrete_type); - - let ty = match infcx - .infer_opaque_definition_from_instantiation(opaque_type_key, concrete_type) - { - Ok(ty) => ty, - Err(err) => { - errors.push(DeferredOpaqueTypeError::InvalidOpaqueTypeArgs(err)); - continue; - } - }; - - // Sometimes, when the hidden type is an inference variable, it can happen that - // the hidden type becomes the opaque type itself. In this case, this was an opaque - // usage of the opaque type and we can ignore it. This check is mirrored in typeck's - // writeback. - if !infcx.next_trait_solver() { - if let ty::Alias(ty::Opaque, alias_ty) = ty.kind() - && alias_ty.def_id == opaque_type_key.def_id.to_def_id() - && alias_ty.args == opaque_type_key.args - { - continue; - } - } - - root_cx.add_concrete_opaque_type( - opaque_type_key.def_id, - OpaqueHiddenType { span: concrete_type.span, ty }, - ); - - // Check that all opaque types have the same region parameters if they have the same - // non-region parameters. This is necessary because within the new solver we perform - // various query operations modulo regions, and thus could unsoundly select some impls - // that don't hold. - if let Some((prev_decl_key, prev_span)) = decls_modulo_regions.insert( - infcx.tcx.erase_regions(opaque_type_key), - (opaque_type_key, concrete_type.span), - ) && let Some((arg1, arg2)) = std::iter::zip( - prev_decl_key.iter_captured_args(infcx.tcx).map(|(_, arg)| arg), - opaque_type_key.iter_captured_args(infcx.tcx).map(|(_, arg)| arg), - ) - .find(|(arg1, arg2)| arg1 != arg2) - { - errors.push(DeferredOpaqueTypeError::LifetimeMismatchOpaqueParam( - LifetimeMismatchOpaqueParam { - arg: arg1, - prev: arg2, - span: prev_span, - prev_span: concrete_type.span, - }, - )); - } - } - - errors - } - - /// Map the regions in the type to named regions. This is similar to what - /// `infer_opaque_types` does, but can infer any universal region, not only - /// ones from the args for the opaque type. It also doesn't double check - /// that the regions produced are in fact equal to the named region they are - /// replaced with. This is fine because this function is only to improve the - /// region names in error messages. - /// - /// This differs from `MirBorrowckCtxt::name_regions` since it is particularly - /// lax with mapping region vids that are *shorter* than a universal region to - /// that universal region. This is useful for member region constraints since - /// we want to suggest a universal region name to capture even if it's technically - /// not equal to the error region. - pub(crate) fn name_regions_for_member_constraint(&self, tcx: TyCtxt<'tcx>, ty: T) -> T - where - T: TypeFoldable>, - { - fold_regions(tcx, ty, |region, _| match region.kind() { - ty::ReVar(vid) => { - let scc = self.constraint_sccs.scc(vid); - - // Special handling of higher-ranked regions. - if !self.max_nameable_universe(scc).is_root() { - match self.scc_values.placeholders_contained_in(scc).enumerate().last() { - // If the region contains a single placeholder then they're equal. - Some((0, placeholder)) => { - return ty::Region::new_placeholder(tcx, placeholder); - } - - // Fallback: this will produce a cryptic error message. - _ => return region, - } - } - - // Find something that we can name - let upper_bound = self.approx_universal_upper_bound(vid); - if let Some(universal_region) = self.definitions[upper_bound].external_name { - return universal_region; - } - - // Nothing exact found, so we pick a named upper bound, if there's only one. - // If there's >1 universal region, then we probably are dealing w/ an intersection - // region which cannot be mapped back to a universal. - // FIXME: We could probably compute the LUB if there is one. - let scc = self.constraint_sccs.scc(vid); - let upper_bounds: Vec<_> = self - .reverse_scc_graph() - .upper_bounds(scc) - .filter_map(|vid| self.definitions[vid].external_name) - .filter(|r| !r.is_static()) - .collect(); - match &upper_bounds[..] { - [universal_region] => *universal_region, - _ => region, - } - } - _ => region, - }) - } -} - -#[extension(pub trait InferCtxtExt<'tcx>)] -impl<'tcx> InferCtxt<'tcx> { - /// Given the fully resolved, instantiated type for an opaque - /// type, i.e., the value of an inference variable like C1 or C2 - /// (*), computes the "definition type" for an opaque type - /// definition -- that is, the inferred value of `Foo1<'x>` or - /// `Foo2<'x>` that we would conceptually use in its definition: - /// ```ignore (illustrative) - /// type Foo1<'x> = impl Bar<'x> = AAA; // <-- this type AAA - /// type Foo2<'x> = impl Bar<'x> = BBB; // <-- or this type BBB - /// fn foo<'a, 'b>(..) -> (Foo1<'a>, Foo2<'b>) { .. } - /// ``` - /// Note that these values are defined in terms of a distinct set of - /// generic parameters (`'x` instead of `'a`) from C1 or C2. The main - /// purpose of this function is to do that translation. - /// - /// (*) C1 and C2 were introduced in the comments on - /// `register_member_constraints`. Read that comment for more context. - /// - /// # Parameters - /// - /// - `def_id`, the `impl Trait` type - /// - `args`, the args used to instantiate this opaque type - /// - `instantiated_ty`, the inferred type C1 -- fully resolved, lifted version of - /// `opaque_defn.concrete_ty` - #[instrument(level = "debug", skip(self))] - fn infer_opaque_definition_from_instantiation( - &self, - opaque_type_key: OpaqueTypeKey<'tcx>, - instantiated_ty: OpaqueHiddenType<'tcx>, - ) -> Result, InvalidOpaqueTypeArgs<'tcx>> { - check_opaque_type_parameter_valid( - self, - opaque_type_key, - instantiated_ty.span, - DefiningScopeKind::MirBorrowck, - )?; - - let definition_ty = instantiated_ty - .remap_generic_params_to_declaration_params( - opaque_type_key, - self.tcx, - DefiningScopeKind::MirBorrowck, - ) - .ty; - - definition_ty.error_reported()?; - Ok(definition_ty) - } -} diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types/member_constraints.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types/member_constraints.rs new file mode 100644 index 0000000000000..e1ae51adf6174 --- /dev/null +++ b/compiler/rustc_borrowck/src/region_infer/opaque_types/member_constraints.rs @@ -0,0 +1,189 @@ +use rustc_data_structures::fx::FxHashMap; +use rustc_hir::def_id::DefId; +use rustc_middle::bug; +use rustc_middle::ty::{ + self, GenericArgsRef, Region, RegionVid, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, + TypeVisitor, +}; +use tracing::{debug, instrument}; + +use super::DefiningUse; +use super::region_ctxt::RegionCtxt; +use crate::constraints::ConstraintSccIndex; + +pub(super) fn apply_member_constraints<'tcx>( + rcx: &mut RegionCtxt<'_, 'tcx>, + defining_uses: &[DefiningUse<'tcx>], +) { + // Start by collecting the member constraints of all defining uses. + // + // Applying member constraints can influence other member constraints, + // so we first collect and then apply them. + let mut member_constraints = Default::default(); + for defining_use in defining_uses { + let mut visitor = CollectMemberConstraintsVisitor { + rcx, + defining_use, + member_constraints: &mut member_constraints, + }; + defining_use.hidden_type.ty.visit_with(&mut visitor); + } + + // Now walk over the region graph, visiting the smallest regions first and then all + // regions which have to outlive that one. + // + // Whenever we encounter a member region, we mutate the value of this SCC. This is + // as if we'd introduce new outlives constraints. However, we discard these region + // values after we've inferred the hidden types of opaques and apply the region + // constraints by simply equating the actual hidden type with the inferred one. + debug!(?member_constraints); + for scc_a in rcx.constraint_sccs.all_sccs() { + debug!(?scc_a); + for &scc_b in rcx.constraint_sccs.successors(scc_a) { + debug!(?scc_b); + rcx.scc_values.add_region(scc_a, scc_b); + } + + for defining_use in member_constraints.get(&scc_a).into_iter().flatten() { + apply_member_constraint(rcx, scc_a, &defining_use.arg_regions); + } + } +} + +#[instrument(level = "debug", skip(rcx))] +fn apply_member_constraint<'tcx>( + rcx: &mut RegionCtxt<'_, 'tcx>, + member: ConstraintSccIndex, + arg_regions: &[RegionVid], +) { + // If the member region lives in a higher universe, we currently choose + // the most conservative option by leaving it unchanged. + if !rcx.max_nameable_universe(member).is_root() { + return; + } + + // The existing value of `'member` is a lower-bound. If its is already larger than + // some universal region, we cannot equate it with that region. Said differently, we + // ignore choice regions which are smaller than this member region. + let mut choice_regions = arg_regions + .iter() + .copied() + .map(|r| rcx.representative(r).rvid()) + .filter(|&choice_region| { + rcx.scc_values.universal_regions_outlived_by(member).all(|lower_bound| { + rcx.universal_region_relations.outlives(choice_region, lower_bound) + }) + }) + .collect::>(); + debug!(?choice_regions, "after enforcing lower-bound"); + + // Now find all the *upper bounds* -- that is, each UB is a + // free region that must outlive the member region `R0` (`UB: + // R0`). Therefore, we need only keep an option `O` if `UB: O` + // for all UB. + // + // If we have a requirement `'upper_bound: 'member`, equating `'member` + // with some region `'choice` means we now also require `'upper_bound: 'choice`. + // Avoid choice regions for which this does not hold. + for ub in rcx.rev_scc_graph.upper_bounds(member) { + choice_regions + .retain(|&choice_region| rcx.universal_region_relations.outlives(ub, choice_region)); + } + debug!(?choice_regions, "after enforcing upper-bound"); + + // At this point we can pick any member of `choice_regions` and would like to choose + // it to be a small as possible. To avoid potential non-determinism we will pick the + // smallest such choice. + // + // Because universal regions are only partially ordered (i.e, not every two regions are + // comparable), we will ignore any region that doesn't compare to all others when picking + // the minimum choice. + // + // For example, consider `choice_regions = ['static, 'a, 'b, 'c, 'd, 'e]`, where + // `'static: 'a, 'static: 'b, 'a: 'c, 'b: 'c, 'c: 'd, 'c: 'e`. + // `['d, 'e]` are ignored because they do not compare - the same goes for `['a, 'b]`. + let totally_ordered_subset = choice_regions.iter().copied().filter(|&r1| { + choice_regions.iter().all(|&r2| { + rcx.universal_region_relations.outlives(r1, r2) + || rcx.universal_region_relations.outlives(r2, r1) + }) + }); + // Now we're left with `['static, 'c]`. Pick `'c` as the minimum! + let Some(min_choice) = totally_ordered_subset.reduce(|r1, r2| { + let r1_outlives_r2 = rcx.universal_region_relations.outlives(r1, r2); + let r2_outlives_r1 = rcx.universal_region_relations.outlives(r2, r1); + match (r1_outlives_r2, r2_outlives_r1) { + (true, true) => r1.min(r2), + (true, false) => r2, + (false, true) => r1, + (false, false) => bug!("incomparable regions in total order"), + } + }) else { + debug!("no unique minimum choice"); + return; + }; + + debug!(?min_choice); + // Lift the member region to be at least as large as this `min_choice` by directly + // mutating the `scc_values` as we compute it. This acts as if we've added a + // `'member: 'min_choice` while not recomputing sccs. This means different sccs + // may now actually be equal. + let min_choice_scc = rcx.constraint_sccs.scc(min_choice); + rcx.scc_values.add_region(member, min_choice_scc); +} + +struct CollectMemberConstraintsVisitor<'a, 'b, 'tcx> { + rcx: &'a RegionCtxt<'a, 'tcx>, + defining_use: &'b DefiningUse<'tcx>, + member_constraints: &'a mut FxHashMap>>, +} +impl<'tcx> CollectMemberConstraintsVisitor<'_, '_, 'tcx> { + fn cx(&self) -> TyCtxt<'tcx> { + self.rcx.infcx.tcx + } + fn visit_closure_args(&mut self, def_id: DefId, args: GenericArgsRef<'tcx>) { + let generics = self.cx().generics_of(def_id); + for arg in args.iter().skip(generics.parent_count) { + arg.visit_with(self); + } + } +} +impl<'tcx> TypeVisitor> for CollectMemberConstraintsVisitor<'_, '_, 'tcx> { + fn visit_region(&mut self, r: Region<'tcx>) { + match r.kind() { + ty::ReBound(..) => return, + ty::ReVar(vid) => { + let scc = self.rcx.constraint_sccs.scc(vid); + self.member_constraints.entry(scc).or_default().push(self.defining_use); + } + _ => unreachable!(), + } + } + + fn visit_ty(&mut self, ty: Ty<'tcx>) { + if !ty.flags().intersects(ty::TypeFlags::HAS_FREE_REGIONS) { + return; + } + + match *ty.kind() { + ty::Closure(def_id, args) + | ty::CoroutineClosure(def_id, args) + | ty::Coroutine(def_id, args) => self.visit_closure_args(def_id, args), + + ty::Alias(kind, ty::AliasTy { def_id, args, .. }) + if let Some(variances) = self.cx().opt_alias_variances(kind, def_id) => + { + // Skip lifetime parameters that are not captured, since they do + // not need member constraints registered for them; we'll erase + // them (and hopefully in the future replace them with placeholders). + for (&v, arg) in std::iter::zip(variances, args.iter()) { + if v != ty::Bivariant { + arg.visit_with(self) + } + } + } + + _ => ty.super_visit_with(self), + } + } +} diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs new file mode 100644 index 0000000000000..6f9798441dc56 --- /dev/null +++ b/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs @@ -0,0 +1,615 @@ +use std::iter; +use std::rc::Rc; + +use rustc_data_structures::frozen::Frozen; +use rustc_data_structures::fx::FxIndexMap; +use rustc_hir::def_id::DefId; +use rustc_infer::infer::outlives::env::RegionBoundPairs; +use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin}; +use rustc_infer::traits::ObligationCause; +use rustc_macros::extension; +use rustc_middle::mir::{Body, ConstraintCategory}; +use rustc_middle::ty::{ + self, DefiningScopeKind, FallibleTypeFolder, GenericArg, GenericArgsRef, OpaqueHiddenType, + OpaqueTypeKey, Region, RegionVid, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, + TypeVisitableExt, fold_regions, +}; +use rustc_mir_dataflow::points::DenseLocationMap; +use rustc_span::Span; +use rustc_trait_selection::opaque_types::{ + InvalidOpaqueTypeArgs, check_opaque_type_parameter_valid, +}; +use rustc_trait_selection::solve::NoSolution; +use rustc_trait_selection::traits::query::type_op::custom::CustomTypeOp; +use tracing::{debug, debug_span, instrument}; + +use super::reverse_sccs::ReverseSccGraph; +use crate::consumers::RegionInferenceContext; +use crate::session_diagnostics::LifetimeMismatchOpaqueParam; +use crate::type_check::canonical::fully_perform_op_raw; +use crate::type_check::free_region_relations::UniversalRegionRelations; +use crate::type_check::{Locations, MirTypeckRegionConstraints}; +use crate::universal_regions::{RegionClassification, UniversalRegions}; +use crate::{BorrowCheckRootCtxt, BorrowckInferCtxt}; + +mod member_constraints; +mod region_ctxt; + +use member_constraints::apply_member_constraints; +use region_ctxt::RegionCtxt; + +pub(crate) enum DeferredOpaqueTypeError<'tcx> { + InvalidOpaqueTypeArgs(InvalidOpaqueTypeArgs<'tcx>), + LifetimeMismatchOpaqueParam(LifetimeMismatchOpaqueParam<'tcx>), + UnexpectedHiddenRegion { + /// The opaque type. + opaque_type_key: OpaqueTypeKey<'tcx>, + /// The hidden type containing the member region. + hidden_type: OpaqueHiddenType<'tcx>, + /// The unexpected region. + member_region: Region<'tcx>, + }, + NonDefiningUseInDefiningScope { + span: Span, + opaque_type_key: OpaqueTypeKey<'tcx>, + }, +} + +pub(crate) fn handle_opaque_type_uses<'tcx>( + root_cx: &mut BorrowCheckRootCtxt<'tcx>, + infcx: &BorrowckInferCtxt<'tcx>, + body: &Body<'tcx>, + universal_region_relations: &Frozen>, + region_bound_pairs: &RegionBoundPairs<'tcx>, + known_type_outlives_obligations: &[ty::PolyTypeOutlivesPredicate<'tcx>], + location_map: &Rc, + constraints: &mut MirTypeckRegionConstraints<'tcx>, +) -> Vec> { + let tcx = infcx.tcx; + let opaque_types = infcx.clone_opaque_types(); + if opaque_types.is_empty() { + return Vec::new(); + } + + let opaque_types_storage_num_entries = infcx.inner.borrow_mut().opaque_types().num_entries(); + // We need to eagerly map all regions to NLL vars here, as we need to make sure we've + // introduced nll vars for all used placeholders. + let mut opaque_types = opaque_types + .into_iter() + .map(|entry| { + fold_regions(tcx, infcx.resolve_vars_if_possible(entry), |r, _| { + let vid = if let ty::RePlaceholder(placeholder) = r.kind() { + constraints.placeholder_region(infcx, placeholder).as_var() + } else { + universal_region_relations.universal_regions.to_region_vid(r) + }; + Region::new_var(tcx, vid) + }) + }) + .collect::>(); + + debug!(?opaque_types); + + let errors = collect_defining_uses( + root_cx, + infcx, + constraints, + universal_region_relations, + location_map, + &mut opaque_types, + ); + + if !errors.is_empty() { + return errors; + } + + let errors = apply_defining_uses( + root_cx, + infcx, + body, + &universal_region_relations.universal_regions, + region_bound_pairs, + known_type_outlives_obligations, + constraints, + &opaque_types, + ); + + for (key, hidden_type) in infcx + .inner + .borrow_mut() + .opaque_types() + .opaque_types_added_since(opaque_types_storage_num_entries) + { + let opaque_type_string = tcx.def_path_str(key.def_id); + let msg = format!("unexpected cyclic definition of `{opaque_type_string}`"); + infcx.dcx().span_delayed_bug(hidden_type.span, msg); + } + + let _ = infcx.take_opaque_types(); + + errors +} + +#[derive(Debug)] +struct DefiningUse<'tcx> { + opaque_type_key: OpaqueTypeKey<'tcx>, + arg_regions: Vec, + hidden_type: OpaqueHiddenType<'tcx>, +} + +fn collect_defining_uses<'tcx>( + root_cx: &mut BorrowCheckRootCtxt<'tcx>, + infcx: &BorrowckInferCtxt<'tcx>, + constraints: &MirTypeckRegionConstraints<'tcx>, + universal_region_relations: &Frozen>, + location_map: &Rc, + opaque_types: &[(OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>)], +) -> Vec> { + let tcx = infcx.tcx; + let mut rcx = + RegionCtxt::new(infcx, universal_region_relations, Rc::clone(location_map), constraints); + + let mut defining_uses = vec![]; + let mut errors = vec![]; + for &(opaque_type_key, hidden_type) in opaque_types { + let non_nll_opaque_type_key = opaque_type_key.fold_captured_lifetime_args(infcx.tcx, |r| { + nll_var_to_universal_region(&rcx, r.as_var()).unwrap_or(r) + }); + if let Err(err) = check_opaque_type_parameter_valid( + infcx, + non_nll_opaque_type_key, + hidden_type.span, + DefiningScopeKind::MirBorrowck, + ) { + if tcx.use_typing_mode_borrowck() { + match err { + InvalidOpaqueTypeArgs::AlreadyReported(guar) => root_cx + .add_concrete_opaque_type( + opaque_type_key.def_id, + OpaqueHiddenType::new_error(tcx, guar), + ), + _ => debug!(?non_nll_opaque_type_key, ?err, "ignoring non-defining use"), + } + } else { + errors.push(DeferredOpaqueTypeError::InvalidOpaqueTypeArgs(err)); + } + continue; + } + + let arg_regions = iter::once(rcx.universal_regions().fr_static) + .chain( + opaque_type_key + .iter_captured_args(tcx) + .filter_map(|(_, arg)| arg.as_region()) + .map(Region::as_var), + ) + .collect(); + defining_uses.push(DefiningUse { opaque_type_key, arg_regions, hidden_type }); + } + + debug!(?defining_uses); + + apply_member_constraints(&mut rcx, &defining_uses); + map_defining_uses_to_definition_site(root_cx, &rcx, &defining_uses, &mut errors); + errors +} + +fn nll_var_to_universal_region<'tcx>( + rcx: &RegionCtxt<'_, 'tcx>, + r: RegionVid, +) -> Option> { + // Use the SCC representative instead of directly using `region`. + // See [rustc-dev-guide chapter] § "Strict lifetime equality". + let vid = rcx.representative(r).rvid(); + match rcx.definitions[vid].origin { + // Iterate over all universal regions in a consistent order and find the + // *first* equal region. This makes sure that equal lifetimes will have + // the same name and simplifies subsequent handling. + // See [rustc-dev-guide chapter] § "Semantic lifetime equality". + NllRegionVariableOrigin::FreeRegion => rcx + .universal_regions() + .universal_regions_iter() + .filter(|&ur| { + // See [rustc-dev-guide chapter] § "Closure restrictions". + !matches!( + rcx.universal_regions().region_classification(ur), + Some(RegionClassification::External) + ) + }) + .find(|&ur| rcx.universal_region_relations.equal(vid, ur)) + .map(|ur| rcx.definitions[ur].external_name.unwrap()), + NllRegionVariableOrigin::Placeholder(placeholder) => { + Some(ty::Region::new_placeholder(rcx.infcx.tcx, placeholder)) + } + NllRegionVariableOrigin::Existential { .. } => None, + } +} + +fn map_defining_uses_to_definition_site<'tcx>( + root_cx: &mut BorrowCheckRootCtxt<'tcx>, + rcx: &RegionCtxt<'_, 'tcx>, + defining_uses: &[DefiningUse<'tcx>], + errors: &mut Vec>, +) { + let infcx = rcx.infcx; + let tcx = infcx.tcx; + let mut decls_modulo_regions: FxIndexMap, (OpaqueTypeKey<'tcx>, Span)> = + FxIndexMap::default(); + for &DefiningUse { opaque_type_key, ref arg_regions, hidden_type } in defining_uses { + let opaque_type_key = opaque_type_key.fold_captured_lifetime_args(infcx.tcx, |r| { + nll_var_to_universal_region(rcx, r.as_var()).unwrap_or_else(|| { + ty::Region::new_error_with_message( + infcx.tcx, + hidden_type.span, + "opaque type with non-universal region args", + ) + }) + }); + let _span = debug_span!( + "map_defining_uses_to_definition_site", + ?opaque_type_key, + ?arg_regions, + ?hidden_type + ); + // After applying member constraints, we now map all regions in the hidden type + // to the `arg_regions` of this defining use. In case a region in the hidden type + // ended up not being equal to any such region, we error. + let mut visitor = ToArgRegionsFolder::new(rcx, arg_regions); + let hidden_type = match hidden_type.try_fold_with(&mut visitor) { + Ok(hidden_type) => hidden_type, + Err(r) => { + errors.push(DeferredOpaqueTypeError::UnexpectedHiddenRegion { + hidden_type, + opaque_type_key, + member_region: ty::Region::new_var(tcx, r), + }); + let guar = tcx.dcx().span_delayed_bug( + hidden_type.span, + "opaque type with non-universal region args", + ); + ty::OpaqueHiddenType::new_error(tcx, guar) + } + }; + let ty = infcx + .infer_opaque_definition_from_instantiation(opaque_type_key, hidden_type) + .unwrap_or_else(|err| { + errors.push(DeferredOpaqueTypeError::InvalidOpaqueTypeArgs(err)); + Ty::new_error_with_message( + rcx.infcx.tcx, + hidden_type.span, + "deferred invalid opaque type args", + ) + }); + + // Sometimes, when the hidden type is an inference variable, it can happen that + // the hidden type becomes the opaque type itself. In this case, this was an opaque + // usage of the opaque type and we can ignore it. This check is mirrored in typeck's + // writeback. + if !rcx.infcx.tcx.use_typing_mode_borrowck() { + if let ty::Alias(ty::Opaque, alias_ty) = ty.kind() + && alias_ty.def_id == opaque_type_key.def_id.to_def_id() + && alias_ty.args == opaque_type_key.args + { + continue; + } + } + + // Check that all opaque types have the same region parameters if they have the same + // non-region parameters. This is necessary because within the new solver we perform + // various query operations modulo regions, and thus could unsoundly select some impls + // that don't hold. + if let Some((prev_decl_key, prev_span)) = decls_modulo_regions.insert( + rcx.infcx.tcx.erase_regions(opaque_type_key), + (opaque_type_key, hidden_type.span), + ) && let Some((arg1, arg2)) = std::iter::zip( + prev_decl_key.iter_captured_args(infcx.tcx).map(|(_, arg)| arg), + opaque_type_key.iter_captured_args(infcx.tcx).map(|(_, arg)| arg), + ) + .find(|(arg1, arg2)| arg1 != arg2) + { + errors.push(DeferredOpaqueTypeError::LifetimeMismatchOpaqueParam( + LifetimeMismatchOpaqueParam { + arg: arg1, + prev: arg2, + span: prev_span, + prev_span: hidden_type.span, + }, + )); + } + root_cx.add_concrete_opaque_type( + opaque_type_key.def_id, + OpaqueHiddenType { span: hidden_type.span, ty }, + ); + } +} +struct ToArgRegionsFolder<'a, 'tcx> { + rcx: &'a RegionCtxt<'a, 'tcx>, + // When folding closure args or bivariant alias arguments, we simply + // ignore non-member regions. However, we still need to map member + // regions to their arg region even if its in a closure argument. + // + // See tests/ui/type-alias-impl-trait/closure_wf_outlives.rs for an example. + erase_unknown_regions: bool, + arg_regions: &'a [RegionVid], +} + +impl<'a, 'tcx> ToArgRegionsFolder<'a, 'tcx> { + fn new( + rcx: &'a RegionCtxt<'a, 'tcx>, + arg_regions: &'a [RegionVid], + ) -> ToArgRegionsFolder<'a, 'tcx> { + ToArgRegionsFolder { rcx, erase_unknown_regions: false, arg_regions } + } + + fn fold_non_member_arg(&mut self, arg: GenericArg<'tcx>) -> GenericArg<'tcx> { + let prev = self.erase_unknown_regions; + self.erase_unknown_regions = true; + let res = arg.try_fold_with(self).unwrap(); + self.erase_unknown_regions = prev; + res + } + + fn fold_closure_args( + &mut self, + def_id: DefId, + args: GenericArgsRef<'tcx>, + ) -> Result, RegionVid> { + let generics = self.cx().generics_of(def_id); + self.cx().mk_args_from_iter(args.iter().enumerate().map(|(index, arg)| { + if index < generics.parent_count { + Ok(self.fold_non_member_arg(arg)) + } else { + arg.try_fold_with(self) + } + })) + } +} +impl<'tcx> FallibleTypeFolder> for ToArgRegionsFolder<'_, 'tcx> { + type Error = RegionVid; + fn cx(&self) -> TyCtxt<'tcx> { + self.rcx.infcx.tcx + } + + fn try_fold_region(&mut self, r: Region<'tcx>) -> Result, RegionVid> { + match r.kind() { + // ignore bound regions, keep visiting + ty::ReBound(_, _) => Ok(r), + _ => { + let r = r.as_var(); + if let Some(arg_region) = self + .arg_regions + .iter() + .copied() + .find(|&arg_vid| self.rcx.eval_equal(r, arg_vid)) + .and_then(|r| nll_var_to_universal_region(self.rcx, r)) + { + Ok(arg_region) + } else if self.erase_unknown_regions { + Ok(self.cx().lifetimes.re_erased) + } else { + Err(r) + } + } + } + } + + fn try_fold_ty(&mut self, ty: Ty<'tcx>) -> Result, RegionVid> { + if !ty.flags().intersects(ty::TypeFlags::HAS_FREE_REGIONS) { + return Ok(ty); + } + + let tcx = self.cx(); + Ok(match *ty.kind() { + ty::Closure(def_id, args) => { + Ty::new_closure(tcx, def_id, self.fold_closure_args(def_id, args)?) + } + + ty::CoroutineClosure(def_id, args) => { + Ty::new_coroutine_closure(tcx, def_id, self.fold_closure_args(def_id, args)?) + } + + ty::Coroutine(def_id, args) => { + Ty::new_coroutine(tcx, def_id, self.fold_closure_args(def_id, args)?) + } + + ty::Alias(kind, ty::AliasTy { def_id, args, .. }) + if let Some(variances) = tcx.opt_alias_variances(kind, def_id) => + { + let args = tcx.mk_args_from_iter(std::iter::zip(variances, args.iter()).map( + |(&v, s)| { + if v == ty::Bivariant { + Ok(self.fold_non_member_arg(s)) + } else { + s.try_fold_with(self) + } + }, + ))?; + ty::AliasTy::new_from_args(tcx, def_id, args).to_ty(tcx) + } + + _ => ty.try_super_fold_with(self)?, + }) + } +} + +fn apply_defining_uses<'tcx>( + root_cx: &mut BorrowCheckRootCtxt<'tcx>, + infcx: &BorrowckInferCtxt<'tcx>, + body: &Body<'tcx>, + universal_regions: &UniversalRegions<'tcx>, + region_bound_pairs: &RegionBoundPairs<'tcx>, + known_type_outlives_obligations: &[ty::PolyTypeOutlivesPredicate<'tcx>], + constraints: &mut MirTypeckRegionConstraints<'tcx>, + opaque_types: &[(OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>)], +) -> Vec> { + let tcx = infcx.tcx; + let mut errors = Vec::new(); + for &(key, hidden_type) in opaque_types { + let Some(expected) = root_cx.get_concrete_opaque_type(key.def_id) else { + if tcx.use_typing_mode_borrowck() { + errors.push(DeferredOpaqueTypeError::NonDefiningUseInDefiningScope { + span: hidden_type.span, + opaque_type_key: key, + }); + let guar = tcx + .dcx() + .span_delayed_bug(hidden_type.span, "non-defining use in the defining scope"); + root_cx + .add_concrete_opaque_type(key.def_id, OpaqueHiddenType::new_error(tcx, guar)); + continue; + } else { + unreachable!() + } + }; + + let expected = ty::fold_regions(tcx, expected.instantiate(tcx, key.args), |re, _dbi| { + match re.kind() { + ty::ReErased => infcx.next_nll_region_var( + NllRegionVariableOrigin::Existential { name: None }, + || crate::RegionCtxt::Existential(None), + ), + _ => re, + } + }); + + let locations = Locations::All(hidden_type.span); + if let Err(guar) = fully_perform_op_raw( + infcx, + body, + universal_regions, + region_bound_pairs, + known_type_outlives_obligations, + constraints, + locations, + ConstraintCategory::OpaqueType, + CustomTypeOp::new( + |ocx| { + let cause = ObligationCause::misc( + hidden_type.span, + body.source.def_id().expect_local(), + ); + let actual_ty = ocx.normalize(&cause, infcx.param_env, hidden_type.ty); + let expected_ty = ocx.normalize(&cause, infcx.param_env, expected.ty); + ocx.eq(&cause, infcx.param_env, actual_ty, expected_ty).map_err(|_| NoSolution) + }, + "equating opaque types", + ), + ) { + root_cx.add_concrete_opaque_type(key.def_id, OpaqueHiddenType::new_error(tcx, guar)); + } + } + errors +} + +impl<'tcx> RegionInferenceContext<'tcx> { + /// Map the regions in the type to named regions. This is similar to what + /// `infer_opaque_types` does, but can infer any universal region, not only + /// ones from the args for the opaque type. It also doesn't double check + /// that the regions produced are in fact equal to the named region they are + /// replaced with. This is fine because this function is only to improve the + /// region names in error messages. + /// + /// This differs from `MirBorrowckCtxt::name_regions` since it is particularly + /// lax with mapping region vids that are *shorter* than a universal region to + /// that universal region. This is useful for member region constraints since + /// we want to suggest a universal region name to capture even if it's technically + /// not equal to the error region. + pub(crate) fn name_regions_for_member_constraint(&self, tcx: TyCtxt<'tcx>, ty: T) -> T + where + T: TypeFoldable>, + { + fold_regions(tcx, ty, |region, _| match region.kind() { + ty::ReVar(vid) => { + let scc = self.constraint_sccs.scc(vid); + + // Special handling of higher-ranked regions. + if !self.max_nameable_universe(scc).is_root() { + match self.scc_values.placeholders_contained_in(scc).enumerate().last() { + // If the region contains a single placeholder then they're equal. + Some((0, placeholder)) => { + return ty::Region::new_placeholder(tcx, placeholder); + } + + // Fallback: this will produce a cryptic error message. + _ => return region, + } + } + + // Find something that we can name + let upper_bound = self.approx_universal_upper_bound(vid); + if let Some(universal_region) = self.definitions[upper_bound].external_name { + return universal_region; + } + + // Nothing exact found, so we pick a named upper bound, if there's only one. + // If there's >1 universal region, then we probably are dealing w/ an intersection + // region which cannot be mapped back to a universal. + // FIXME: We could probably compute the LUB if there is one. + let scc = self.constraint_sccs.scc(vid); + let rev_scc_graph = + ReverseSccGraph::compute(&self.constraint_sccs, self.universal_regions()); + let upper_bounds: Vec<_> = rev_scc_graph + .upper_bounds(scc) + .filter_map(|vid| self.definitions[vid].external_name) + .filter(|r| !r.is_static()) + .collect(); + match &upper_bounds[..] { + [universal_region] => *universal_region, + _ => region, + } + } + _ => region, + }) + } +} + +#[extension(pub trait InferCtxtExt<'tcx>)] +impl<'tcx> InferCtxt<'tcx> { + /// Given the fully resolved, instantiated type for an opaque + /// type, i.e., the value of an inference variable like C1 or C2 + /// (*), computes the "definition type" for an opaque type + /// definition -- that is, the inferred value of `Foo1<'x>` or + /// `Foo2<'x>` that we would conceptually use in its definition: + /// ```ignore (illustrative) + /// type Foo1<'x> = impl Bar<'x> = AAA; // <-- this type AAA + /// type Foo2<'x> = impl Bar<'x> = BBB; // <-- or this type BBB + /// fn foo<'a, 'b>(..) -> (Foo1<'a>, Foo2<'b>) { .. } + /// ``` + /// Note that these values are defined in terms of a distinct set of + /// generic parameters (`'x` instead of `'a`) from C1 or C2. The main + /// purpose of this function is to do that translation. + /// + /// (*) C1 and C2 were introduced in the comments on + /// `register_member_constraints`. Read that comment for more context. + /// + /// # Parameters + /// + /// - `def_id`, the `impl Trait` type + /// - `args`, the args used to instantiate this opaque type + /// - `instantiated_ty`, the inferred type C1 -- fully resolved, lifted version of + /// `opaque_defn.concrete_ty` + #[instrument(level = "debug", skip(self))] + fn infer_opaque_definition_from_instantiation( + &self, + opaque_type_key: OpaqueTypeKey<'tcx>, + instantiated_ty: OpaqueHiddenType<'tcx>, + ) -> Result, InvalidOpaqueTypeArgs<'tcx>> { + check_opaque_type_parameter_valid( + self, + opaque_type_key, + instantiated_ty.span, + DefiningScopeKind::MirBorrowck, + )?; + + let definition_ty = instantiated_ty + .remap_generic_params_to_declaration_params( + opaque_type_key, + self.tcx, + DefiningScopeKind::MirBorrowck, + ) + .ty; + + definition_ty.error_reported()?; + Ok(definition_ty) + } +} diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types/region_ctxt.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types/region_ctxt.rs new file mode 100644 index 0000000000000..26e3d4e39903c --- /dev/null +++ b/compiler/rustc_borrowck/src/region_infer/opaque_types/region_ctxt.rs @@ -0,0 +1,112 @@ +use std::rc::Rc; + +use rustc_data_structures::frozen::Frozen; +use rustc_index::IndexVec; +use rustc_infer::infer::NllRegionVariableOrigin; +use rustc_middle::ty::{RegionVid, UniverseIndex}; +use rustc_mir_dataflow::points::DenseLocationMap; + +use crate::BorrowckInferCtxt; +use crate::constraints::ConstraintSccIndex; +use crate::handle_placeholders::{SccAnnotations, region_definitions}; +use crate::region_infer::reverse_sccs::ReverseSccGraph; +use crate::region_infer::values::RegionValues; +use crate::region_infer::{ConstraintSccs, RegionDefinition, RegionTracker, Representative}; +use crate::type_check::MirTypeckRegionConstraints; +use crate::type_check::free_region_relations::UniversalRegionRelations; +use crate::universal_regions::UniversalRegions; + +/// A slimmed down version of [crate::region_infer::RegionInferenceContext] used +/// only by opaque type handling. +pub(super) struct RegionCtxt<'a, 'tcx> { + pub(super) infcx: &'a BorrowckInferCtxt<'tcx>, + pub(super) definitions: Frozen>>, + pub(super) universal_region_relations: &'a UniversalRegionRelations<'tcx>, + pub(super) constraint_sccs: ConstraintSccs, + pub(super) scc_annotations: IndexVec, + pub(super) rev_scc_graph: ReverseSccGraph, + pub(super) scc_values: RegionValues, +} + +impl<'a, 'tcx> RegionCtxt<'a, 'tcx> { + /// Creates a new `RegionCtxt` used to compute defining opaque type uses. + /// + /// This does not yet propagate region values. This is instead done lazily + /// when applying member constraints. + pub(super) fn new( + infcx: &'a BorrowckInferCtxt<'tcx>, + universal_region_relations: &'a Frozen>, + location_map: Rc, + constraints: &MirTypeckRegionConstraints<'tcx>, + ) -> RegionCtxt<'a, 'tcx> { + let universal_regions = &universal_region_relations.universal_regions; + let (definitions, _has_placeholders) = region_definitions(infcx, universal_regions); + let mut scc_annotations = SccAnnotations::init(&definitions); + let constraint_sccs = ConstraintSccs::new_with_annotation( + &constraints + .outlives_constraints + .graph(definitions.len()) + .region_graph(&constraints.outlives_constraints, universal_regions.fr_static), + &mut scc_annotations, + ); + let scc_annotations = scc_annotations.scc_to_annotation; + + // Unlike the `RegionInferenceContext`, we only care about free regions + // and fully ignore liveness and placeholders. + let placeholder_indices = Default::default(); + let mut scc_values = + RegionValues::new(location_map, universal_regions.len(), placeholder_indices); + for variable in definitions.indices() { + let scc = constraint_sccs.scc(variable); + match definitions[variable].origin { + NllRegionVariableOrigin::FreeRegion => { + scc_values.add_element(scc, variable); + } + _ => {} + } + } + + let rev_scc_graph = ReverseSccGraph::compute(&constraint_sccs, universal_regions); + RegionCtxt { + infcx, + definitions, + universal_region_relations, + constraint_sccs, + scc_annotations, + rev_scc_graph, + scc_values, + } + } + + pub(super) fn representative(&self, vid: RegionVid) -> Representative { + let scc = self.constraint_sccs.scc(vid); + self.scc_annotations[scc].representative + } + + /// The largest universe of any region nameable from this SCC. + pub(super) fn max_nameable_universe(&self, scc: ConstraintSccIndex) -> UniverseIndex { + self.scc_annotations[scc].max_nameable_universe() + } + + pub(super) fn universal_regions(&self) -> &UniversalRegions<'tcx> { + &self.universal_region_relations.universal_regions + } + + pub(super) fn eval_equal(&self, r1_vid: RegionVid, r2_vid: RegionVid) -> bool { + let r1 = self.constraint_sccs.scc(r1_vid); + let r2 = self.constraint_sccs.scc(r2_vid); + + if r1 == r2 { + return true; + } + + let universal_outlives = |sub, sup| { + self.scc_values.universal_regions_outlived_by(sub).all(|r1| { + self.scc_values + .universal_regions_outlived_by(sup) + .any(|r2| self.universal_region_relations.outlives(r2, r1)) + }) + }; + universal_outlives(r1, r2) && universal_outlives(r2, r1) + } +} diff --git a/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs b/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs index 604265f894081..e8da85eccef16 100644 --- a/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs +++ b/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs @@ -5,7 +5,6 @@ use rustc_data_structures::graph; use rustc_data_structures::graph::vec_graph::VecGraph; use rustc_middle::ty::RegionVid; -use crate::RegionInferenceContext; use crate::constraints::ConstraintSccIndex; use crate::region_infer::ConstraintSccs; use crate::universal_regions::UniversalRegions; @@ -57,12 +56,3 @@ impl ReverseSccGraph { .filter(move |r| duplicates.insert(*r)) } } - -impl RegionInferenceContext<'_> { - /// Return the reverse graph of the region SCCs, initialising it if needed. - pub(super) fn reverse_scc_graph(&self) -> &ReverseSccGraph { - self.rev_scc_graph.get_or_init(|| { - ReverseSccGraph::compute(&self.constraint_sccs, self.universal_regions()) - }) - } -} diff --git a/compiler/rustc_borrowck/src/root_cx.rs b/compiler/rustc_borrowck/src/root_cx.rs index 9b1d12aede513..40c0448cf0ba0 100644 --- a/compiler/rustc_borrowck/src/root_cx.rs +++ b/compiler/rustc_borrowck/src/root_cx.rs @@ -2,7 +2,7 @@ use rustc_abi::FieldIdx; use rustc_data_structures::fx::FxHashMap; use rustc_hir::def_id::LocalDefId; use rustc_middle::bug; -use rustc_middle::ty::{OpaqueHiddenType, Ty, TyCtxt, TypeVisitableExt}; +use rustc_middle::ty::{EarlyBinder, OpaqueHiddenType, Ty, TyCtxt, TypeVisitableExt}; use rustc_span::ErrorGuaranteed; use smallvec::SmallVec; @@ -19,7 +19,7 @@ pub(super) struct BorrowCheckRootCtxt<'tcx> { tainted_by_errors: Option, /// This should be `None` during normal compilation. See [`crate::consumers`] for more /// information on how this is used. - pub(crate) consumer: Option>, + pub consumer: Option>, } impl<'tcx> BorrowCheckRootCtxt<'tcx> { @@ -67,6 +67,13 @@ impl<'tcx> BorrowCheckRootCtxt<'tcx> { } } + pub(super) fn get_concrete_opaque_type( + &mut self, + def_id: LocalDefId, + ) -> Option>> { + self.concrete_opaque_types.0.get(&def_id).map(|ty| EarlyBinder::bind(*ty)) + } + pub(super) fn set_tainted_by_errors(&mut self, guar: ErrorGuaranteed) { self.tainted_by_errors = Some(guar); } diff --git a/compiler/rustc_borrowck/src/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs index b3fa786a5177c..a8a48248ffd87 100644 --- a/compiler/rustc_borrowck/src/type_check/canonical.rs +++ b/compiler/rustc_borrowck/src/type_check/canonical.rs @@ -2,8 +2,9 @@ use std::fmt; use rustc_errors::ErrorGuaranteed; use rustc_infer::infer::canonical::Canonical; +use rustc_infer::infer::outlives::env::RegionBoundPairs; use rustc_middle::bug; -use rustc_middle::mir::ConstraintCategory; +use rustc_middle::mir::{Body, ConstraintCategory}; use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, Upcast}; use rustc_span::Span; use rustc_span::def_id::DefId; @@ -14,7 +15,69 @@ use rustc_trait_selection::traits::query::type_op::{self, TypeOpOutput}; use tracing::{debug, instrument}; use super::{Locations, NormalizeLocation, TypeChecker}; +use crate::BorrowckInferCtxt; use crate::diagnostics::ToUniverseInfo; +use crate::type_check::{MirTypeckRegionConstraints, constraint_conversion}; +use crate::universal_regions::UniversalRegions; + +#[instrument(skip(infcx, constraints, op), level = "trace")] +pub(crate) fn fully_perform_op_raw<'tcx, R: fmt::Debug, Op>( + infcx: &BorrowckInferCtxt<'tcx>, + body: &Body<'tcx>, + universal_regions: &UniversalRegions<'tcx>, + region_bound_pairs: &RegionBoundPairs<'tcx>, + known_type_outlives_obligations: &[ty::PolyTypeOutlivesPredicate<'tcx>], + constraints: &mut MirTypeckRegionConstraints<'tcx>, + locations: Locations, + category: ConstraintCategory<'tcx>, + op: Op, +) -> Result +where + Op: type_op::TypeOp<'tcx, Output = R>, + Op::ErrorInfo: ToUniverseInfo<'tcx>, +{ + let old_universe = infcx.universe(); + + let TypeOpOutput { output, constraints: query_constraints, error_info } = + op.fully_perform(infcx, locations.span(body))?; + if cfg!(debug_assertions) { + let data = infcx.take_and_reset_region_constraints(); + if !data.is_empty() { + panic!("leftover region constraints: {data:#?}"); + } + } + + debug!(?output, ?query_constraints); + + if let Some(data) = query_constraints { + constraint_conversion::ConstraintConversion::new( + infcx, + universal_regions, + region_bound_pairs, + infcx.param_env, + known_type_outlives_obligations, + locations, + locations.span(body), + category, + constraints, + ) + .convert_all(data); + } + + // If the query has created new universes and errors are going to be emitted, register the + // cause of these new universes for improved diagnostics. + let universe = infcx.universe(); + if old_universe != universe + && let Some(error_info) = error_info + { + let universe_info = error_info.to_universe_info(old_universe); + for u in (old_universe + 1)..=universe { + constraints.universe_causes.insert(u, universe_info.clone()); + } + } + + Ok(output) +} impl<'a, 'tcx> TypeChecker<'a, 'tcx> { /// Given some operation `op` that manipulates types, proves @@ -38,36 +101,17 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { Op: type_op::TypeOp<'tcx, Output = R>, Op::ErrorInfo: ToUniverseInfo<'tcx>, { - let old_universe = self.infcx.universe(); - - let TypeOpOutput { output, constraints, error_info } = - op.fully_perform(self.infcx, locations.span(self.body))?; - if cfg!(debug_assertions) { - let data = self.infcx.take_and_reset_region_constraints(); - if !data.is_empty() { - panic!("leftover region constraints: {data:#?}"); - } - } - - debug!(?output, ?constraints); - - if let Some(data) = constraints { - self.push_region_constraints(locations, category, data); - } - - // If the query has created new universes and errors are going to be emitted, register the - // cause of these new universes for improved diagnostics. - let universe = self.infcx.universe(); - if old_universe != universe - && let Some(error_info) = error_info - { - let universe_info = error_info.to_universe_info(old_universe); - for u in (old_universe + 1)..=universe { - self.constraints.universe_causes.insert(u, universe_info.clone()); - } - } - - Ok(output) + fully_perform_op_raw( + self.infcx, + self.body, + self.universal_regions, + self.region_bound_pairs, + self.known_type_outlives_obligations, + self.constraints, + locations, + category, + op, + ) } pub(super) fn instantiate_canonical( diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs index c3aa205d5aab3..af8d2e128caca 100644 --- a/compiler/rustc_borrowck/src/type_check/mod.rs +++ b/compiler/rustc_borrowck/src/type_check/mod.rs @@ -26,8 +26,7 @@ use rustc_middle::ty::adjustment::PointerCoercion; use rustc_middle::ty::cast::CastTy; use rustc_middle::ty::{ self, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, CoroutineArgsExt, - GenericArgsRef, OpaqueHiddenType, OpaqueTypeKey, RegionVid, Ty, TyCtxt, TypeVisitableExt, - UserArgs, UserTypeAnnotationIndex, fold_regions, + GenericArgsRef, Ty, TyCtxt, TypeVisitableExt, UserArgs, UserTypeAnnotationIndex, fold_regions, }; use rustc_middle::{bug, span_bug}; use rustc_mir_dataflow::move_paths::MoveData; @@ -42,7 +41,6 @@ use tracing::{debug, instrument, trace}; use crate::borrow_set::BorrowSet; use crate::constraints::{OutlivesConstraint, OutlivesConstraintSet}; use crate::diagnostics::UniverseInfo; -use crate::member_constraints::MemberConstraintSet; use crate::polonius::legacy::{PoloniusFacts, PoloniusLocationTable}; use crate::polonius::{PoloniusContext, PoloniusLivenessContext}; use crate::region_infer::TypeTest; @@ -67,12 +65,11 @@ macro_rules! span_mirbug { }) } -mod canonical; +pub(crate) mod canonical; mod constraint_conversion; pub(crate) mod free_region_relations; mod input_output; pub(crate) mod liveness; -mod opaque_types; mod relate_tys; /// Type checks the given `mir` in the context of the inference @@ -114,7 +111,6 @@ pub(crate) fn type_check<'tcx>( placeholder_index_to_region: IndexVec::default(), liveness_constraints: LivenessValues::with_specific_points(Rc::clone(&location_map)), outlives_constraints: OutlivesConstraintSet::default(), - member_constraints: MemberConstraintSet::default(), type_tests: Vec::default(), universe_causes: FxIndexMap::default(), }; @@ -170,9 +166,6 @@ pub(crate) fn type_check<'tcx>( liveness::generate(&mut typeck, &location_map, move_data); - let opaque_type_values = - opaque_types::take_opaques_and_register_member_constraints(&mut typeck); - // We're done with typeck, we can finalize the polonius liveness context for region inference. let polonius_context = typeck.polonius_liveness.take().map(|liveness_context| { PoloniusContext::create_from_liveness( @@ -187,7 +180,6 @@ pub(crate) fn type_check<'tcx>( if let Some(guar) = universal_region_relations.universal_regions.encountered_re_error() { debug!("encountered an error region; removing constraints!"); constraints.outlives_constraints = Default::default(); - constraints.member_constraints = Default::default(); constraints.type_tests = Default::default(); root_cx.set_tainted_by_errors(guar); infcx.set_tainted_by_errors(guar); @@ -196,7 +188,8 @@ pub(crate) fn type_check<'tcx>( MirTypeckResults { constraints, universal_region_relations, - opaque_type_values, + region_bound_pairs, + known_type_outlives_obligations, polonius_context, } } @@ -245,7 +238,8 @@ struct TypeChecker<'a, 'tcx> { pub(crate) struct MirTypeckResults<'tcx> { pub(crate) constraints: MirTypeckRegionConstraints<'tcx>, pub(crate) universal_region_relations: Frozen>, - pub(crate) opaque_type_values: FxIndexMap, OpaqueHiddenType<'tcx>>, + pub(crate) region_bound_pairs: Frozen>, + pub(crate) known_type_outlives_obligations: Frozen>>, pub(crate) polonius_context: Option, } @@ -277,8 +271,6 @@ pub(crate) struct MirTypeckRegionConstraints<'tcx> { pub(crate) outlives_constraints: OutlivesConstraintSet<'tcx>, - pub(crate) member_constraints: MemberConstraintSet<'tcx, RegionVid>, - pub(crate) universe_causes: FxIndexMap>, pub(crate) type_tests: Vec>, @@ -287,7 +279,7 @@ pub(crate) struct MirTypeckRegionConstraints<'tcx> { impl<'tcx> MirTypeckRegionConstraints<'tcx> { /// Creates a `Region` for a given `PlaceholderRegion`, or returns the /// region that corresponds to a previously created one. - fn placeholder_region( + pub(crate) fn placeholder_region( &mut self, infcx: &InferCtxt<'tcx>, placeholder: ty::PlaceholderRegion, @@ -380,14 +372,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { self.body } - fn to_region_vid(&mut self, r: ty::Region<'tcx>) -> RegionVid { - if let ty::RePlaceholder(placeholder) = r.kind() { - self.constraints.placeholder_region(self.infcx, placeholder).as_var() - } else { - self.universal_regions.to_region_vid(r) - } - } - fn unsized_feature_enabled(&self) -> bool { self.tcx().features().unsized_fn_params() } diff --git a/compiler/rustc_borrowck/src/type_check/opaque_types.rs b/compiler/rustc_borrowck/src/type_check/opaque_types.rs deleted file mode 100644 index 5a422483eef41..0000000000000 --- a/compiler/rustc_borrowck/src/type_check/opaque_types.rs +++ /dev/null @@ -1,333 +0,0 @@ -use std::iter; - -use rustc_data_structures::fx::FxIndexMap; -use rustc_middle::span_bug; -use rustc_middle::ty::{ - self, GenericArgKind, OpaqueHiddenType, OpaqueTypeKey, Ty, TyCtxt, TypeSuperVisitable, - TypeVisitable, TypeVisitableExt, TypeVisitor, fold_regions, -}; -use tracing::{debug, trace}; - -use super::{MemberConstraintSet, TypeChecker}; - -/// Once we're done with typechecking the body, we take all the opaque types -/// defined by this function and add their 'member constraints'. -pub(super) fn take_opaques_and_register_member_constraints<'tcx>( - typeck: &mut TypeChecker<'_, 'tcx>, -) -> FxIndexMap, OpaqueHiddenType<'tcx>> { - let infcx = typeck.infcx; - // Annoying: to invoke `typeck.to_region_vid`, we need access to - // `typeck.constraints`, but we also want to be mutating - // `typeck.member_constraints`. For now, just swap out the value - // we want and replace at the end. - let mut member_constraints = std::mem::take(&mut typeck.constraints.member_constraints); - let opaque_types = infcx - .take_opaque_types() - .into_iter() - .map(|(opaque_type_key, hidden_type)| { - let hidden_type = infcx.resolve_vars_if_possible(hidden_type); - register_member_constraints( - typeck, - &mut member_constraints, - opaque_type_key, - hidden_type, - ); - trace!("finalized opaque type {:?} to {:#?}", opaque_type_key, hidden_type.ty.kind()); - if hidden_type.has_non_region_infer() { - span_bug!(hidden_type.span, "could not resolve {:?}", hidden_type.ty); - } - - // Convert all regions to nll vars. - let (opaque_type_key, hidden_type) = - fold_regions(infcx.tcx, (opaque_type_key, hidden_type), |r, _| { - ty::Region::new_var(infcx.tcx, typeck.to_region_vid(r)) - }); - - (opaque_type_key, hidden_type) - }) - .collect(); - assert!(typeck.constraints.member_constraints.is_empty()); - typeck.constraints.member_constraints = member_constraints; - opaque_types -} - -/// Given the map `opaque_types` containing the opaque -/// `impl Trait` types whose underlying, hidden types are being -/// inferred, this method adds constraints to the regions -/// appearing in those underlying hidden types to ensure that they -/// at least do not refer to random scopes within the current -/// function. These constraints are not (quite) sufficient to -/// guarantee that the regions are actually legal values; that -/// final condition is imposed after region inference is done. -/// -/// # The Problem -/// -/// Let's work through an example to explain how it works. Assume -/// the current function is as follows: -/// -/// ```text -/// fn foo<'a, 'b>(..) -> (impl Bar<'a>, impl Bar<'b>) -/// ``` -/// -/// Here, we have two `impl Trait` types whose values are being -/// inferred (the `impl Bar<'a>` and the `impl -/// Bar<'b>`). Conceptually, this is sugar for a setup where we -/// define underlying opaque types (`Foo1`, `Foo2`) and then, in -/// the return type of `foo`, we *reference* those definitions: -/// -/// ```text -/// type Foo1<'x> = impl Bar<'x>; -/// type Foo2<'x> = impl Bar<'x>; -/// fn foo<'a, 'b>(..) -> (Foo1<'a>, Foo2<'b>) { .. } -/// // ^^^^ ^^ -/// // | | -/// // | args -/// // def_id -/// ``` -/// -/// As indicating in the comments above, each of those references -/// is (in the compiler) basically generic parameters (`args`) -/// applied to the type of a suitable `def_id` (which identifies -/// `Foo1` or `Foo2`). -/// -/// Now, at this point in compilation, what we have done is to -/// replace each of the references (`Foo1<'a>`, `Foo2<'b>`) with -/// fresh inference variables C1 and C2. We wish to use the values -/// of these variables to infer the underlying types of `Foo1` and -/// `Foo2`. That is, this gives rise to higher-order (pattern) unification -/// constraints like: -/// -/// ```text -/// for<'a> (Foo1<'a> = C1) -/// for<'b> (Foo1<'b> = C2) -/// ``` -/// -/// For these equation to be satisfiable, the types `C1` and `C2` -/// can only refer to a limited set of regions. For example, `C1` -/// can only refer to `'static` and `'a`, and `C2` can only refer -/// to `'static` and `'b`. The job of this function is to impose that -/// constraint. -/// -/// Up to this point, C1 and C2 are basically just random type -/// inference variables, and hence they may contain arbitrary -/// regions. In fact, it is fairly likely that they do! Consider -/// this possible definition of `foo`: -/// -/// ```text -/// fn foo<'a, 'b>(x: &'a i32, y: &'b i32) -> (impl Bar<'a>, impl Bar<'b>) { -/// (&*x, &*y) -/// } -/// ``` -/// -/// Here, the values for the concrete types of the two impl -/// traits will include inference variables: -/// -/// ```text -/// &'0 i32 -/// &'1 i32 -/// ``` -/// -/// Ordinarily, the subtyping rules would ensure that these are -/// sufficiently large. But since `impl Bar<'a>` isn't a specific -/// type per se, we don't get such constraints by default. This -/// is where this function comes into play. It adds extra -/// constraints to ensure that all the regions which appear in the -/// inferred type are regions that could validly appear. -/// -/// This is actually a bit of a tricky constraint in general. We -/// want to say that each variable (e.g., `'0`) can only take on -/// values that were supplied as arguments to the opaque type -/// (e.g., `'a` for `Foo1<'a>`) or `'static`, which is always in -/// scope. We don't have a constraint quite of this kind in the current -/// region checker. -/// -/// # The Solution -/// -/// We generally prefer to make `<=` constraints, since they -/// integrate best into the region solver. To do that, we find the -/// "minimum" of all the arguments that appear in the args: that -/// is, some region which is less than all the others. In the case -/// of `Foo1<'a>`, that would be `'a` (it's the only choice, after -/// all). Then we apply that as a least bound to the variables -/// (e.g., `'a <= '0`). -/// -/// In some cases, there is no minimum. Consider this example: -/// -/// ```text -/// fn baz<'a, 'b>() -> impl Trait<'a, 'b> { ... } -/// ``` -/// -/// Here we would report a more complex "in constraint", like `'r -/// in ['a, 'b, 'static]` (where `'r` is some region appearing in -/// the hidden type). -/// -/// # Constrain regions, not the hidden concrete type -/// -/// Note that generating constraints on each region `Rc` is *not* -/// the same as generating an outlives constraint on `Tc` itself. -/// For example, if we had a function like this: -/// -/// ``` -/// # #![feature(type_alias_impl_trait)] -/// # fn main() {} -/// # trait Foo<'a> {} -/// # impl<'a, T> Foo<'a> for (&'a u32, T) {} -/// fn foo<'a, T>(x: &'a u32, y: T) -> impl Foo<'a> { -/// (x, y) -/// } -/// -/// // Equivalent to: -/// # mod dummy { use super::*; -/// type FooReturn<'a, T> = impl Foo<'a>; -/// #[define_opaque(FooReturn)] -/// fn foo<'a, T>(x: &'a u32, y: T) -> FooReturn<'a, T> { -/// (x, y) -/// } -/// # } -/// ``` -/// -/// then the hidden type `Tc` would be `(&'0 u32, T)` (where `'0` -/// is an inference variable). If we generated a constraint that -/// `Tc: 'a`, then this would incorrectly require that `T: 'a` -- -/// but this is not necessary, because the opaque type we -/// create will be allowed to reference `T`. So we only generate a -/// constraint that `'0: 'a`. -fn register_member_constraints<'tcx>( - typeck: &mut TypeChecker<'_, 'tcx>, - member_constraints: &mut MemberConstraintSet<'tcx, ty::RegionVid>, - opaque_type_key: OpaqueTypeKey<'tcx>, - OpaqueHiddenType { span, ty: hidden_ty }: OpaqueHiddenType<'tcx>, -) { - let tcx = typeck.tcx(); - let hidden_ty = typeck.infcx.resolve_vars_if_possible(hidden_ty); - debug!(?hidden_ty); - - let variances = tcx.variances_of(opaque_type_key.def_id); - debug!(?variances); - - // For a case like `impl Foo<'a, 'b>`, we would generate a constraint - // `'r in ['a, 'b, 'static]` for each region `'r` that appears in the - // hidden type (i.e., it must be equal to `'a`, `'b`, or `'static`). - // - // `conflict1` and `conflict2` are the two region bounds that we - // detected which were unrelated. They are used for diagnostics. - - // Create the set of choice regions: each region in the hidden - // type can be equal to any of the region parameters of the - // opaque type definition. - let fr_static = typeck.universal_regions.fr_static; - let choice_regions: Vec<_> = opaque_type_key - .args - .iter() - .enumerate() - .filter(|(i, _)| variances[*i] == ty::Invariant) - .filter_map(|(_, arg)| match arg.kind() { - GenericArgKind::Lifetime(r) => Some(typeck.to_region_vid(r)), - GenericArgKind::Type(_) | GenericArgKind::Const(_) => None, - }) - .chain(iter::once(fr_static)) - .collect(); - - // FIXME(#42940): This should use the `FreeRegionsVisitor`, but that's - // not currently sound until we have existential regions. - hidden_ty.visit_with(&mut ConstrainOpaqueTypeRegionVisitor { - tcx, - op: |r| { - member_constraints.add_member_constraint( - opaque_type_key, - hidden_ty, - span, - typeck.to_region_vid(r), - &choice_regions, - ) - }, - }); -} - -/// Visitor that requires that (almost) all regions in the type visited outlive -/// `least_region`. We cannot use `push_outlives_components` because regions in -/// closure signatures are not included in their outlives components. We need to -/// ensure all regions outlive the given bound so that we don't end up with, -/// say, `ReVar` appearing in a return type and causing ICEs when other -/// functions end up with region constraints involving regions from other -/// functions. -/// -/// We also cannot use `for_each_free_region` because for closures it includes -/// the regions parameters from the enclosing item. -/// -/// We ignore any type parameters because impl trait values are assumed to -/// capture all the in-scope type parameters. -struct ConstrainOpaqueTypeRegionVisitor<'tcx, OP: FnMut(ty::Region<'tcx>)> { - tcx: TyCtxt<'tcx>, - op: OP, -} - -impl<'tcx, OP> TypeVisitor> for ConstrainOpaqueTypeRegionVisitor<'tcx, OP> -where - OP: FnMut(ty::Region<'tcx>), -{ - fn visit_region(&mut self, r: ty::Region<'tcx>) { - match r.kind() { - // ignore bound regions, keep visiting - ty::ReBound(_, _) => {} - _ => (self.op)(r), - } - } - - fn visit_ty(&mut self, ty: Ty<'tcx>) { - // We're only interested in types involving regions - if !ty.flags().intersects(ty::TypeFlags::HAS_FREE_REGIONS) { - return; - } - - match *ty.kind() { - ty::Closure(_, args) => { - // Skip lifetime parameters of the enclosing item(s) - - for upvar in args.as_closure().upvar_tys() { - upvar.visit_with(self); - } - args.as_closure().sig_as_fn_ptr_ty().visit_with(self); - } - - ty::CoroutineClosure(_, args) => { - // Skip lifetime parameters of the enclosing item(s) - - for upvar in args.as_coroutine_closure().upvar_tys() { - upvar.visit_with(self); - } - - args.as_coroutine_closure().signature_parts_ty().visit_with(self); - } - - ty::Coroutine(_, args) => { - // Skip lifetime parameters of the enclosing item(s) - // Also skip the witness type, because that has no free regions. - - for upvar in args.as_coroutine().upvar_tys() { - upvar.visit_with(self); - } - args.as_coroutine().return_ty().visit_with(self); - args.as_coroutine().yield_ty().visit_with(self); - args.as_coroutine().resume_ty().visit_with(self); - } - - ty::Alias(kind, ty::AliasTy { def_id, args, .. }) - if let Some(variances) = self.tcx.opt_alias_variances(kind, def_id) => - { - // Skip lifetime parameters that are not captured, since they do - // not need member constraints registered for them; we'll erase - // them (and hopefully in the future replace them with placeholders). - for (v, s) in std::iter::zip(variances, args.iter()) { - if *v != ty::Bivariant { - s.visit_with(self); - } - } - } - - _ => { - ty.super_visit_with(self); - } - } - } -} diff --git a/compiler/rustc_trait_selection/src/opaque_types.rs b/compiler/rustc_trait_selection/src/opaque_types.rs index d5bde9192d5e2..70a08f34f336b 100644 --- a/compiler/rustc_trait_selection/src/opaque_types.rs +++ b/compiler/rustc_trait_selection/src/opaque_types.rs @@ -13,6 +13,7 @@ use crate::errors::NonGenericOpaqueTypeParam; use crate::regions::OutlivesEnvironmentBuildExt; use crate::traits::ObligationCtxt; +#[derive(Debug)] pub enum InvalidOpaqueTypeArgs<'tcx> { AlreadyReported(ErrorGuaranteed), NotAParam { opaque_type_key: OpaqueTypeKey<'tcx>, param_index: usize, span: Span }, diff --git a/tests/ui/async-await/async-borrowck-escaping-block-error.stderr b/tests/ui/async-await/async-borrowck-escaping-block-error.stderr index 8410e7eca5796..6ea03c99aa0e8 100644 --- a/tests/ui/async-await/async-borrowck-escaping-block-error.stderr +++ b/tests/ui/async-await/async-borrowck-escaping-block-error.stderr @@ -6,11 +6,7 @@ LL | Box::new(async { x } ) | | | may outlive borrowed value `x` | -note: async block is returned here - --> $DIR/async-borrowck-escaping-block-error.rs:6:5 - | -LL | Box::new(async { x } ) - | ^^^^^^^^^^^^^^^^^^^^^^ + = note: async blocks are not executed immediately and must either take a reference or ownership of outside variables they use help: to force the async block to take ownership of `x` (and any other referenced variables), use the `move` keyword | LL | Box::new(async move { x } ) diff --git a/tests/ui/async-await/issue-74072-lifetime-name-annotations.stderr b/tests/ui/async-await/issue-74072-lifetime-name-annotations.stderr index e1f268116fc54..96975f5ec72b2 100644 --- a/tests/ui/async-await/issue-74072-lifetime-name-annotations.stderr +++ b/tests/ui/async-await/issue-74072-lifetime-name-annotations.stderr @@ -53,7 +53,7 @@ LL | || let y = &*x; LL | || *x += 1; LL | || y LL | || })() - | ||______^_- argument requires that borrow lasts for `'1` + | ||______^_- opaque type requires that borrow lasts for `'1` | |_______| | creates a temporary value which is freed while still in use LL | } @@ -102,7 +102,7 @@ LL | || let y = &*x; LL | || *x += 1; LL | || y LL | || })() - | ||______^_- argument requires that borrow lasts for `'1` + | ||______^_- opaque type requires that borrow lasts for `'1` | |_______| | creates a temporary value which is freed while still in use LL | } diff --git a/tests/ui/async-await/issue-76547.rs b/tests/ui/async-await/issue-76547.rs index 30a39c8943789..24decf9b5f77e 100644 --- a/tests/ui/async-await/issue-76547.rs +++ b/tests/ui/async-await/issue-76547.rs @@ -17,8 +17,8 @@ impl<'a> Future for ListFut<'a> { } async fn fut(bufs: &mut [&mut [u8]]) { - ListFut(bufs).await //~^ ERROR lifetime may not live long enough + ListFut(bufs).await } pub struct ListFut2<'a>(&'a mut [&'a mut [u8]]); @@ -31,8 +31,8 @@ impl<'a> Future for ListFut2<'a> { } async fn fut2(bufs: &mut [&mut [u8]]) -> i32 { - ListFut2(bufs).await //~^ ERROR lifetime may not live long enough + ListFut2(bufs).await } fn main() {} diff --git a/tests/ui/async-await/issue-76547.stderr b/tests/ui/async-await/issue-76547.stderr index 4d96cce824b91..5131f05423413 100644 --- a/tests/ui/async-await/issue-76547.stderr +++ b/tests/ui/async-await/issue-76547.stderr @@ -1,12 +1,15 @@ error: lifetime may not live long enough - --> $DIR/issue-76547.rs:20:13 + --> $DIR/issue-76547.rs:19:38 | -LL | async fn fut(bufs: &mut [&mut [u8]]) { - | - - let's call the lifetime of this reference `'2` - | | - | let's call the lifetime of this reference `'1` -LL | ListFut(bufs).await - | ^^^^ this usage requires that `'1` must outlive `'2` +LL | async fn fut(bufs: &mut [&mut [u8]]) { + | ____________________-_____-___________^ + | | | | + | | | let's call the lifetime of this reference `'2` + | | let's call the lifetime of this reference `'1` +LL | | +LL | | ListFut(bufs).await +LL | | } + | |_^ opaque type requires that `'1` must outlive `'2` | help: consider introducing a named lifetime parameter | @@ -14,14 +17,17 @@ LL | async fn fut<'a>(bufs: &'a mut [&'a mut [u8]]) { | ++++ ++ ++ error: lifetime may not live long enough - --> $DIR/issue-76547.rs:34:14 + --> $DIR/issue-76547.rs:33:46 | -LL | async fn fut2(bufs: &mut [&mut [u8]]) -> i32 { - | - - let's call the lifetime of this reference `'2` - | | - | let's call the lifetime of this reference `'1` -LL | ListFut2(bufs).await - | ^^^^ this usage requires that `'1` must outlive `'2` +LL | async fn fut2(bufs: &mut [&mut [u8]]) -> i32 { + | _____________________-_____-__________________^ + | | | | + | | | let's call the lifetime of this reference `'2` + | | let's call the lifetime of this reference `'1` +LL | | +LL | | ListFut2(bufs).await +LL | | } + | |_^ opaque type requires that `'1` must outlive `'2` | help: consider introducing a named lifetime parameter | diff --git a/tests/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr b/tests/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr index 167b5ee4425f8..8fea6bf95806c 100644 --- a/tests/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr +++ b/tests/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr @@ -9,7 +9,7 @@ LL | async fn async_ret_impl_trait3<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trai LL | | LL | | (a, b) LL | | } - | |_^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a` + | |_^ opaque type requires that `'a` must outlive `'b` | = help: consider adding the following bound: `'a: 'b` diff --git a/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.rs b/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.rs index c7a37a8184854..123e23d610752 100644 --- a/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.rs +++ b/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.rs @@ -5,12 +5,12 @@ struct Point { x: i32, y: i32, } -fn foo () -> impl FnMut()->() { +fn foo () -> impl FnMut() { let mut p = Point {x: 1, y: 2 }; let mut c = || { - //~^ ERROR closure may outlive the current function, but it borrows `p` - p.x+=5; + p.x += 5; println!("{:?}", p); + //~^ ERROR `p` does not live long enough }; c } diff --git a/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.stderr b/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.stderr index d47f0539b84b2..96910375e09da 100644 --- a/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.stderr +++ b/tests/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.stderr @@ -1,22 +1,23 @@ -error[E0373]: closure may outlive the current function, but it borrows `p`, which is owned by the current function - --> $DIR/borrowck-4.rs:10:17 +error[E0597]: `p` does not live long enough + --> $DIR/borrowck-4.rs:12:25 | -LL | let mut c = || { - | ^^ may outlive borrowed value `p` -... -LL | println!("{:?}", p); - | - `p` is borrowed here - | -note: closure is returned here - --> $DIR/borrowck-4.rs:15:5 - | -LL | c - | ^ -help: to force the closure to take ownership of `p` (and any other referenced variables), use the `move` keyword - | -LL | let mut c = move || { - | ++++ +LL | let mut p = Point {x: 1, y: 2 }; + | ----- binding `p` declared here +LL | let mut c = || { + | -- + | | + | _________________value captured here + | | +LL | | p.x += 5; +LL | | println!("{:?}", p); + | | ^ borrowed value does not live long enough +LL | | +LL | | }; + | |_____- assignment requires that `p` is borrowed for `'static` +LL | c +LL | } + | - `p` dropped here while still borrowed error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0373`. +For more information about this error, try `rustc --explain E0597`. diff --git a/tests/ui/impl-trait/does-not-live-long-enough.stderr b/tests/ui/impl-trait/does-not-live-long-enough.stderr index cfc13298071a5..9f3918ce3e082 100644 --- a/tests/ui/impl-trait/does-not-live-long-enough.stderr +++ b/tests/ui/impl-trait/does-not-live-long-enough.stderr @@ -1,12 +1,14 @@ error[E0373]: closure may outlive the current function, but it borrows `prefix`, which is owned by the current function --> $DIR/does-not-live-long-enough.rs:6:33 | +LL | fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator { + | -- lifetime `'a` defined here LL | self.data.iter().filter(|s| s.starts_with(prefix)).map(|s| s.as_ref()) | ^^^ ------ `prefix` is borrowed here | | | may outlive borrowed value `prefix` | -note: closure is returned here +note: function requires argument type to outlive `'a` --> $DIR/does-not-live-long-enough.rs:6:9 | LL | self.data.iter().filter(|s| s.starts_with(prefix)).map(|s| s.as_ref()) diff --git a/tests/ui/impl-trait/member-constraints/apply_member_constraint-no-req-eq.rs b/tests/ui/impl-trait/member-constraints/apply_member_constraint-no-req-eq.rs index 3aa52fe264472..e9af42b30e9bb 100644 --- a/tests/ui/impl-trait/member-constraints/apply_member_constraint-no-req-eq.rs +++ b/tests/ui/impl-trait/member-constraints/apply_member_constraint-no-req-eq.rs @@ -1,5 +1,7 @@ //@ check-pass -// FIXME(-Znext-solver): enable this test +//@ revisions: current next +//@ ignore-compare-mode-next-solver (explicit revisions) +//@[next] compile-flags: -Znext-solver trait Id { type This; diff --git a/tests/ui/impl-trait/member-constraints/nested-impl-trait-pass.rs b/tests/ui/impl-trait/member-constraints/nested-impl-trait-pass.rs index 6860fc5e6a532..878b8746bfa5d 100644 --- a/tests/ui/impl-trait/member-constraints/nested-impl-trait-pass.rs +++ b/tests/ui/impl-trait/member-constraints/nested-impl-trait-pass.rs @@ -1,7 +1,9 @@ // Nested impl-traits can impose different member constraints on the same region variable. //@ check-pass -// FIXME(-Znext-solver): enable this test +//@ revisions: current next +//@ ignore-compare-mode-next-solver (explicit revisions) +//@[next] compile-flags: -Znext-solver trait Cap<'a> {} impl Cap<'_> for T {} diff --git a/tests/ui/impl-trait/nested-rpit-hrtb.rs b/tests/ui/impl-trait/nested-rpit-hrtb.rs index 11d79bcff7371..f4ff13d6c20f9 100644 --- a/tests/ui/impl-trait/nested-rpit-hrtb.rs +++ b/tests/ui/impl-trait/nested-rpit-hrtb.rs @@ -48,6 +48,7 @@ fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc = im // This should resolve. fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {} //~^ ERROR implementation of `Bar` is not general enough +//~| ERROR lifetime may not live long enough // This should resolve. fn two_htrb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Qux<'b>> {} diff --git a/tests/ui/impl-trait/nested-rpit-hrtb.stderr b/tests/ui/impl-trait/nested-rpit-hrtb.stderr index 2e95ef370c7fd..93cd7bd788f45 100644 --- a/tests/ui/impl-trait/nested-rpit-hrtb.stderr +++ b/tests/ui/impl-trait/nested-rpit-hrtb.stderr @@ -1,5 +1,5 @@ error[E0261]: use of undeclared lifetime name `'b` - --> $DIR/nested-rpit-hrtb.rs:56:77 + --> $DIR/nested-rpit-hrtb.rs:57:77 | LL | fn two_htrb_outlives() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {} | ^^ undeclared lifetime @@ -15,7 +15,7 @@ LL | fn two_htrb_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Siz | ++++ error[E0261]: use of undeclared lifetime name `'b` - --> $DIR/nested-rpit-hrtb.rs:64:82 + --> $DIR/nested-rpit-hrtb.rs:65:82 | LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {} | ^^ undeclared lifetime @@ -87,6 +87,12 @@ LL | fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc but trait `Qux<'_>` is implemented for `()` = help: for that trait implementation, expected `()`, found `&'a ()` +error: lifetime may not live long enough + --> $DIR/nested-rpit-hrtb.rs:49:93 + | +LL | fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {} + | -- lifetime `'b` defined here ^^ opaque type requires that `'b` must outlive `'static` + error: implementation of `Bar` is not general enough --> $DIR/nested-rpit-hrtb.rs:49:93 | @@ -97,7 +103,7 @@ LL | fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = = note: ...but it actually implements `Bar<'0>`, for some specific lifetime `'0` error[E0277]: the trait bound `for<'a, 'b> &'a (): Qux<'b>` is not satisfied - --> $DIR/nested-rpit-hrtb.rs:60:64 + --> $DIR/nested-rpit-hrtb.rs:61:64 | LL | fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Qux<'b>> {} | ^^^^^^^^^^^^^^^^^^^^ the trait `for<'a, 'b> Qux<'b>` is not implemented for `&'a ()` @@ -106,7 +112,7 @@ LL | fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> but trait `Qux<'_>` is implemented for `()` = help: for that trait implementation, expected `()`, found `&'a ()` -error: aborting due to 9 previous errors +error: aborting due to 10 previous errors Some errors have detailed explanations: E0261, E0277, E0657. For more information about an error, try `rustc --explain E0261`. diff --git a/tests/ui/impl-trait/no-anonymize-regions.rs b/tests/ui/impl-trait/no-anonymize-regions.rs index 4f7f7c0641c65..a89c9e05a34d5 100644 --- a/tests/ui/impl-trait/no-anonymize-regions.rs +++ b/tests/ui/impl-trait/no-anonymize-regions.rs @@ -1,5 +1,7 @@ //@ check-pass -// FIXME(-Znext-solver): enable this test +//@ revisions: current next +//@ ignore-compare-mode-next-solver (explicit revisions) +//@[next] compile-flags: -Znext-solver // A regression test for an error in `redis` while working on #139587. // diff --git a/tests/ui/impl-trait/non-defining-uses/as-projection-term.next.stderr b/tests/ui/impl-trait/non-defining-uses/as-projection-term.next.stderr index 08c8365b1805a..96e242d5d4851 100644 --- a/tests/ui/impl-trait/non-defining-uses/as-projection-term.next.stderr +++ b/tests/ui/impl-trait/non-defining-uses/as-projection-term.next.stderr @@ -1,12 +1,8 @@ -error[E0792]: expected generic lifetime parameter, found `'_` +error: non-defining use of `impl Sized + '_` in the defining scope --> $DIR/as-projection-term.rs:14:19 | -LL | fn recur<'a>() -> impl Sized + 'a { - | -- this generic parameter must be used with a generic lifetime parameter -... LL | prove_proj(|| recur()); | ^^^^^^^ error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/impl-trait/non-defining-uses/as-projection-term.rs b/tests/ui/impl-trait/non-defining-uses/as-projection-term.rs index 4c5adc7a00ab1..f0cf333b6a13b 100644 --- a/tests/ui/impl-trait/non-defining-uses/as-projection-term.rs +++ b/tests/ui/impl-trait/non-defining-uses/as-projection-term.rs @@ -12,6 +12,6 @@ fn recur<'a>() -> impl Sized + 'a { // inference variable at this point, we unify it with `opaque<'1>` and // end up ignoring that defining use as the hidden type is equal to its key. prove_proj(|| recur()); - //[next]~^ ERROR expected generic lifetime parameter, found `'_` + //[next]~^ ERROR non-defining use of `impl Sized + '_` in the defining scope } fn main() {} diff --git a/tests/ui/impl-trait/wf-check-hidden-type.stderr b/tests/ui/impl-trait/wf-check-hidden-type.stderr index 86ba7aff54ada..0cbfc50272029 100644 --- a/tests/ui/impl-trait/wf-check-hidden-type.stderr +++ b/tests/ui/impl-trait/wf-check-hidden-type.stderr @@ -6,7 +6,7 @@ LL | fn boom<'a, 'b>() -> impl Extend<'a, 'b> { | | | lifetime `'a` defined here LL | None::<&'_ &'_ ()> - | ^^^^^^^^^^^^^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a` + | ^^^^^^^^^^^^^^^^^^ opaque type requires that `'a` must outlive `'b` | = help: consider adding the following bound: `'a: 'b` diff --git a/tests/ui/nll/ice-106874.stderr b/tests/ui/nll/ice-106874.stderr index ead4d490a6248..006e5f64e5080 100644 --- a/tests/ui/nll/ice-106874.stderr +++ b/tests/ui/nll/ice-106874.stderr @@ -17,6 +17,12 @@ LL | A(B(C::new(D::new(move |st| f(st))))) = note: ...but it actually implements `FnOnce<(&'1 mut V,)>`, for some specific lifetime `'1` = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` +error: higher-ranked subtype error + --> $DIR/ice-106874.rs:8:5 + | +LL | A(B(C::new(D::new(move |st| f(st))))) + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + error: implementation of `Fn` is not general enough --> $DIR/ice-106874.rs:8:7 | @@ -78,13 +84,5 @@ error: higher-ranked subtype error LL | A(B(C::new(D::new(move |st| f(st))))) | ^ -error: higher-ranked subtype error - --> $DIR/ice-106874.rs:8:41 - | -LL | A(B(C::new(D::new(move |st| f(st))))) - | ^ - | - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - error: aborting due to 10 previous errors diff --git a/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.rs b/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.rs index 80a4ab35527a1..5fa13152653c5 100644 --- a/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.rs +++ b/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.rs @@ -31,6 +31,7 @@ mod capture_tait { #[define_opaque(Opq2)] fn test() -> Opq2 {} //~^ ERROR hidden type for `capture_tait::Opq0` captures lifetime that does not appear in bounds + //~| ERROR expected generic lifetime parameter, found `'a` } mod capture_tait_complex_pass { @@ -52,7 +53,8 @@ mod capture_tait_complex_fail { type Opq2 = impl for<'a> Trait<'a, Ty = Opq1<'a>>; #[define_opaque(Opq2)] fn test() -> Opq2 {} - //~^ ERROR hidden type for `capture_tait_complex_fail::Opq0<'a>` captures lifetime that does not appear in bounds + //~^ ERROR expected generic lifetime parameter, found `'a` + //~| ERROR expected generic lifetime parameter, found `'a` } // non-defining use because 'static is used. diff --git a/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.stderr b/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.stderr index 665b9a9169657..8e2c02f15c5d0 100644 --- a/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.stderr +++ b/tests/ui/rfcs/type-alias-impl-trait/higher-ranked-regions-basic.stderr @@ -16,6 +16,15 @@ LL | fn test() -> impl for<'a> Trait<'a, Ty = impl Sized> {} | | opaque type defined here | hidden type `&'a ()` captures the lifetime `'a` as defined here +error[E0792]: expected generic lifetime parameter, found `'a` + --> $DIR/higher-ranked-regions-basic.rs:32:23 + | +LL | type Opq1<'a> = impl for<'b> Trait<'b, Ty = Opq0>; + | -- this generic parameter must be used with a generic lifetime parameter +... +LL | fn test() -> Opq2 {} + | ^^ + error[E0700]: hidden type for `capture_tait::Opq0` captures lifetime that does not appear in bounds --> $DIR/higher-ranked-regions-basic.rs:32:23 | @@ -28,7 +37,7 @@ LL | fn test() -> Opq2 {} | ^^ error[E0792]: expected generic lifetime parameter, found `'a` - --> $DIR/higher-ranked-regions-basic.rs:42:23 + --> $DIR/higher-ranked-regions-basic.rs:43:23 | LL | type Opq1<'a> = impl for<'b> Trait<'b, Ty = Opq0<'b>>; // <- Note 'b | -- this generic parameter must be used with a generic lifetime parameter @@ -37,7 +46,7 @@ LL | fn test() -> Opq2 {} | ^^ error[E0792]: expected generic lifetime parameter, found `'b` - --> $DIR/higher-ranked-regions-basic.rs:42:23 + --> $DIR/higher-ranked-regions-basic.rs:43:23 | LL | type Opq0<'a> = impl Sized; | -- this generic parameter must be used with a generic lifetime parameter @@ -45,19 +54,26 @@ LL | type Opq0<'a> = impl Sized; LL | fn test() -> Opq2 {} | ^^ -error[E0700]: hidden type for `capture_tait_complex_fail::Opq0<'a>` captures lifetime that does not appear in bounds - --> $DIR/higher-ranked-regions-basic.rs:54:23 +error[E0792]: expected generic lifetime parameter, found `'a` + --> $DIR/higher-ranked-regions-basic.rs:55:23 | -LL | type Opq0<'a> = impl Sized; - | ---------- opaque type defined here LL | type Opq1<'a> = impl for<'b> Trait<'b, Ty = Opq0<'a>>; // <- Note 'a - | -- hidden type `&'b ()` captures the lifetime `'b` as defined here + | -- this generic parameter must be used with a generic lifetime parameter +... +LL | fn test() -> Opq2 {} + | ^^ + +error[E0792]: expected generic lifetime parameter, found `'a` + --> $DIR/higher-ranked-regions-basic.rs:55:23 + | +LL | type Opq0<'a> = impl Sized; + | -- this generic parameter must be used with a generic lifetime parameter ... LL | fn test() -> Opq2 {} | ^^ error[E0792]: expected generic lifetime parameter, found `'a` - --> $DIR/higher-ranked-regions-basic.rs:63:65 + --> $DIR/higher-ranked-regions-basic.rs:65:65 | LL | type Opq0<'a, 'b> = impl Sized; | -- this generic parameter must be used with a generic lifetime parameter @@ -66,7 +82,7 @@ LL | fn test() -> impl for<'a> Trait<'a, Ty = Opq0<'a, 'static>> {} | ^^ error[E0792]: expected generic lifetime parameter, found `'a` - --> $DIR/higher-ranked-regions-basic.rs:72:60 + --> $DIR/higher-ranked-regions-basic.rs:74:60 | LL | type Opq0<'a, 'b> = impl Sized; | -- this generic parameter must be used with a generic lifetime parameter @@ -75,7 +91,7 @@ LL | fn test() -> impl for<'a> Trait<'a, Ty = Opq0<'a, 'a>> {} | ^^ error[E0792]: expected generic lifetime parameter, found `'a` - --> $DIR/higher-ranked-regions-basic.rs:82:23 + --> $DIR/higher-ranked-regions-basic.rs:84:23 | LL | type Opq1<'a> = impl for<'b> Trait<'b, Ty = Opq0<'a, 'b>>; | -- this generic parameter must be used with a generic lifetime parameter @@ -84,7 +100,7 @@ LL | fn test() -> Opq2 {} | ^^ error[E0792]: expected generic lifetime parameter, found `'a` - --> $DIR/higher-ranked-regions-basic.rs:82:23 + --> $DIR/higher-ranked-regions-basic.rs:84:23 | LL | type Opq0<'a, 'b> = impl Sized; | -- this generic parameter must be used with a generic lifetime parameter @@ -92,7 +108,7 @@ LL | type Opq0<'a, 'b> = impl Sized; LL | fn test() -> Opq2 {} | ^^ -error: aborting due to 10 previous errors +error: aborting due to 12 previous errors Some errors have detailed explanations: E0700, E0792. For more information about an error, try `rustc --explain E0700`. diff --git a/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.rs b/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.rs index c24672816acdb..0f257a3cd2403 100644 --- a/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.rs +++ b/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.rs @@ -18,7 +18,7 @@ mod bav { impl Bar for i32 {} fn use_it<'a>(val: Box>) -> impl OtherTrait<'a> { - val.use_self() //~ ERROR cannot return value referencing function parameter + val.use_self() //~ ERROR `val` does not live long enough } } diff --git a/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr b/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr index 505765d2b41f6..6f33b33580b86 100644 --- a/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr +++ b/tests/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.stderr @@ -1,11 +1,17 @@ -error[E0515]: cannot return value referencing function parameter `val` +error[E0597]: `val` does not live long enough --> $DIR/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.rs:21:9 | +LL | fn use_it<'a>(val: Box>) -> impl OtherTrait<'a> { + | -- --- binding `val` declared here + | | + | lifetime `'a` defined here LL | val.use_self() - | ---^^^^^^^^^^^ + | ^^^----------- | | - | returns a value referencing data owned by the current function - | `val` is borrowed here + | borrowed value does not live long enough + | opaque type requires that `val` is borrowed for `'a` +LL | } + | - `val` dropped here while still borrowed error[E0515]: cannot return value referencing function parameter `val` --> $DIR/impl-on-dyn-trait-with-implicit-static-bound-needing-more-suggestions.rs:43:9 @@ -70,5 +76,5 @@ LL | val.use_self() error: aborting due to 6 previous errors -Some errors have detailed explanations: E0515, E0521. +Some errors have detailed explanations: E0515, E0521, E0597. For more information about an error, try `rustc --explain E0515`. diff --git a/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr b/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr index 3a1f685f16b79..9a3cfa9987ab1 100644 --- a/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr +++ b/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr @@ -8,7 +8,7 @@ LL | | LL | | .filter_map(|_| foo(src)) | |_________________________________^ | - = note: hidden type `FilterMap, {closure@$DIR/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs:9:21: 9:24}>` captures lifetime `'_` + = note: hidden type `FilterMap, {closure@$DIR/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs:9:21: 9:24}>` captures lifetime `'_` error: aborting due to 1 previous error diff --git a/tests/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr b/tests/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr index c77ef79e7ed18..62c591a0db630 100644 --- a/tests/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr +++ b/tests/ui/suggestions/lifetimes/trait-object-nested-in-impl-trait.stderr @@ -8,7 +8,7 @@ LL | | LL | | current: None, LL | | remaining: self.0.iter(), LL | | } - | |_________^ returning this value requires that `'1` must outlive `'static` + | |_________^ opaque type requires that `'1` must outlive `'static` | help: to declare that `impl Iterator>` captures data from argument `self`, you can add an explicit `'_` lifetime bound | @@ -63,7 +63,7 @@ LL | | LL | | current: None, LL | | remaining: self.0.iter(), LL | | } - | |_________^ returning this value requires that `'a` must outlive `'static` + | |_________^ opaque type requires that `'a` must outlive `'static` | help: to declare that `impl Iterator>` captures data from argument `self`, you can add an explicit `'a` lifetime bound | diff --git a/tests/ui/type-alias-impl-trait/different_args_considered_equal2.rs b/tests/ui/type-alias-impl-trait/different_args_considered_equal2.rs index 902d6ca57e6c9..5c6ad2cc7257f 100644 --- a/tests/ui/type-alias-impl-trait/different_args_considered_equal2.rs +++ b/tests/ui/type-alias-impl-trait/different_args_considered_equal2.rs @@ -8,7 +8,7 @@ fn get_one<'a>(a: *mut &'a str) -> impl IntoIterator> { Some(a) } else { None::> - //~^ ERROR hidden type for `Opaque<'static>` captures lifetime that does not appear in bounds + //~^ ERROR expected generic lifetime parameter, found `'static` } } diff --git a/tests/ui/type-alias-impl-trait/different_args_considered_equal2.stderr b/tests/ui/type-alias-impl-trait/different_args_considered_equal2.stderr index 562ab4168b536..2cb8f03235af2 100644 --- a/tests/ui/type-alias-impl-trait/different_args_considered_equal2.stderr +++ b/tests/ui/type-alias-impl-trait/different_args_considered_equal2.stderr @@ -1,15 +1,12 @@ -error[E0700]: hidden type for `Opaque<'static>` captures lifetime that does not appear in bounds +error[E0792]: expected generic lifetime parameter, found `'static` --> $DIR/different_args_considered_equal2.rs:10:9 | LL | pub type Opaque<'a> = impl Sized; - | ---------- opaque type defined here -... -LL | fn get_one<'a>(a: *mut &'a str) -> impl IntoIterator> { - | -- hidden type `*mut &'a str` captures the lifetime `'a` as defined here + | -- cannot use static lifetime; use a bound lifetime instead or remove the lifetime parameter from the opaque type ... LL | None::> | ^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0700`. +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.member_constraints.stderr b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.member_constraints.stderr index 4a5360c9922e9..43e887f36c5fe 100644 --- a/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.member_constraints.stderr +++ b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.member_constraints.stderr @@ -1,15 +1,12 @@ -error[E0700]: hidden type for `Opaque<'x>` captures lifetime that does not appear in bounds +error[E0792]: expected generic lifetime parameter, found `'_` --> $DIR/generic-not-strictly-equal.rs:34:5 | LL | type Opaque<'a> = impl Copy + Captures<'a>; - | ------------------------ opaque type defined here -... -LL | fn test<'x>(_: Opaque<'x>) { - | -- hidden type `&'x u8` captures the lifetime `'x` as defined here + | -- this generic parameter must be used with a generic lifetime parameter ... LL | relate(opaque, hidden); // defining use: Opaque<'?1> := u8 | ^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0700`. +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.rs b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.rs index c1059e3da3342..42f363d0e575b 100644 --- a/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.rs +++ b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.rs @@ -32,8 +32,7 @@ fn test<'x>(_: Opaque<'x>) { ensure_outlives::<'x>(opaque); // outlives constraint: '?1: 'x relate(opaque, hidden); // defining use: Opaque<'?1> := u8 - //[basic]~^ ERROR expected generic lifetime parameter, found `'_` - //[member_constraints]~^^ ERROR captures lifetime that does not appear in bounds + //~^ ERROR expected generic lifetime parameter, found `'_` } fn main() {} diff --git a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.rs b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.rs index baeba1d3de635..013651e87759e 100644 --- a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.rs +++ b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.rs @@ -9,7 +9,7 @@ impl Foo for () { type Assoc<'a, 'b> = impl Sized; fn bar<'a: 'a, 'b: 'b>(x: &'a ()) -> Self::Assoc<'a, 'b> { let closure = |x: &'a ()| -> Self::Assoc<'b, 'a> { x }; - //~^ ERROR `<() as Foo>::Assoc<'b, 'a>` captures lifetime that does not appear in bounds + //~^ ERROR expected generic lifetime parameter, found `'_` x } } diff --git a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.stderr b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.stderr index a7d3e7f0be403..f399520e7fd3f 100644 --- a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.stderr +++ b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound.stderr @@ -1,13 +1,12 @@ -error[E0700]: hidden type for `<() as Foo>::Assoc<'b, 'a>` captures lifetime that does not appear in bounds +error[E0792]: expected generic lifetime parameter, found `'_` --> $DIR/in-assoc-ty-early-bound.rs:11:60 | LL | type Assoc<'a, 'b> = impl Sized; - | ---------- opaque type defined here + | -- this generic parameter must be used with a generic lifetime parameter LL | fn bar<'a: 'a, 'b: 'b>(x: &'a ()) -> Self::Assoc<'a, 'b> { - | -- hidden type `&'a ()` captures the lifetime `'a` as defined here LL | let closure = |x: &'a ()| -> Self::Assoc<'b, 'a> { x }; | ^ error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0700`. +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.rs b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.rs index 92c8a8f321625..21df53c43d7ca 100644 --- a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.rs +++ b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.rs @@ -13,7 +13,7 @@ impl Foo for () { { let _ = |x: &'a ()| { let _: Self::Assoc<'a> = x; - //~^ ERROR `<() as Foo>::Assoc<'a>` captures lifetime that does not appear in bound + //~^ ERROR expected generic lifetime parameter, found `'_` }; } } diff --git a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.stderr b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.stderr index 7ce4517fb1e9a..aaed03e739b4c 100644 --- a/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.stderr +++ b/tests/ui/type-alias-impl-trait/in-assoc-ty-early-bound2.stderr @@ -1,14 +1,12 @@ -error[E0700]: hidden type for `<() as Foo>::Assoc<'a>` captures lifetime that does not appear in bounds +error[E0792]: expected generic lifetime parameter, found `'_` --> $DIR/in-assoc-ty-early-bound2.rs:15:20 | LL | type Assoc<'a> = impl Sized; - | ---------- opaque type defined here -LL | fn bar<'a: 'a>() - | -- hidden type `&'a ()` captures the lifetime `'a` as defined here + | -- this generic parameter must be used with a generic lifetime parameter ... LL | let _: Self::Assoc<'a> = x; | ^^^^^^^^^^^^^^^ error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0700`. +For more information about this error, try `rustc --explain E0792`.