| use std::cell::{Cell, RefCell}; | |
| use std::fmt; | |
| pub use at::DefineOpaqueTypes; | |
| use free_regions::RegionRelations; | |
| pub use freshen::TypeFreshener; | |
| use lexical_region_resolve::LexicalRegionResolutions; | |
| pub use lexical_region_resolve::RegionResolutionError; | |
| pub use opaque_types::{OpaqueTypeStorage, OpaqueTypeStorageEntries, OpaqueTypeTable}; | |
| use region_constraints::{ | |
| GenericKind, RegionConstraintCollector, RegionConstraintStorage, VarInfos, VerifyBound, | |
| }; | |
| pub use relate::StructurallyRelateAliases; | |
| pub use relate::combine::PredicateEmittingRelation; | |
| use rustc_data_structures::fx::{FxHashSet, FxIndexMap}; | |
| use rustc_data_structures::undo_log::{Rollback, UndoLogs}; | |
| use rustc_data_structures::unify as ut; | |
| use rustc_errors::{DiagCtxtHandle, ErrorGuaranteed}; | |
| use rustc_hir::def_id::{DefId, LocalDefId}; | |
| use rustc_hir::{self as hir, HirId}; | |
| use rustc_index::IndexVec; | |
| use rustc_macros::extension; | |
| pub use rustc_macros::{TypeFoldable, TypeVisitable}; | |
| use rustc_middle::bug; | |
| use rustc_middle::infer::canonical::{CanonicalQueryInput, CanonicalVarValues}; | |
| use rustc_middle::mir::ConstraintCategory; | |
| use rustc_middle::traits::select; | |
| use rustc_middle::traits::solve::Goal; | |
| use rustc_middle::ty::error::{ExpectedFound, TypeError}; | |
| use rustc_middle::ty::{ | |
| self, BoundVarReplacerDelegate, ConstVid, FloatVid, GenericArg, GenericArgKind, GenericArgs, | |
| GenericArgsRef, GenericParamDefKind, InferConst, IntVid, OpaqueTypeKey, ProvisionalHiddenType, | |
| PseudoCanonicalInput, Term, TermKind, Ty, TyCtxt, TyVid, TypeFoldable, TypeFolder, | |
| TypeSuperFoldable, TypeVisitable, TypeVisitableExt, TypingEnv, TypingMode, fold_regions, | |
| }; | |
| use rustc_span::{DUMMY_SP, Span, Symbol}; | |
| use rustc_type_ir::MayBeErased; | |
| use snapshot::undo_log::InferCtxtUndoLogs; | |
| use tracing::{debug, instrument}; | |
| use type_variable::TypeVariableOrigin; | |
| use crate::infer::snapshot::undo_log::UndoLog; | |
| use crate::infer::type_variable::FloatVariableOrigin; | |
| use crate::infer::unify_key::{ConstVariableOrigin, ConstVariableValue, ConstVidKey}; | |
| use crate::traits::{ | |
| self, ObligationCause, ObligationInspector, PredicateObligation, PredicateObligations, | |
| TraitEngine, | |
| }; | |
| pub mod at; | |
| pub mod canonical; | |
| mod context; | |
| mod free_regions; | |
| mod freshen; | |
| mod lexical_region_resolve; | |
| mod opaque_types; | |
| pub mod outlives; | |
| mod projection; | |
| pub mod region_constraints; | |
| pub mod relate; | |
| pub mod resolve; | |
| pub(crate) mod snapshot; | |
| mod type_variable; | |
| mod unify_key; | |
| /// `InferOk<'tcx, ()>` is used a lot. It may seem like a useless wrapper | |
| /// around `PredicateObligations<'tcx>`, but it has one important property: | |
| /// because `InferOk` is marked with `#[must_use]`, if you have a method | |
| /// `InferCtxt::f` that returns `InferResult<'tcx, ()>` and you call it with | |
| /// `infcx.f()?;` you'll get a warning about the obligations being discarded | |
| /// without use, which is probably unintentional and has been a source of bugs | |
| /// in the past. | |
| #[must_use] | |
| #[derive(Debug)] | |
| pub struct InferOk<'tcx, T> { | |
| pub value: T, | |
| pub obligations: PredicateObligations<'tcx>, | |
| } | |
| pub type InferResult<'tcx, T> = Result<InferOk<'tcx, T>, TypeError<'tcx>>; | |
| pub(crate) type FixupResult<T> = Result<T, FixupError>; // "fixup result" | |
| pub(crate) type UnificationTable<'a, 'tcx, T> = ut::UnificationTable< | |
| ut::InPlace<T, &'a mut ut::UnificationStorage<T>, &'a mut InferCtxtUndoLogs<'tcx>>, | |
| >; | |
| /// This type contains all the things within `InferCtxt` that sit within a | |
| /// `RefCell` and are involved with taking/rolling back snapshots. Snapshot | |
| /// operations are hot enough that we want only one call to `borrow_mut` per | |
| /// call to `start_snapshot` and `rollback_to`. | |
| #[derive(Clone)] | |
| pub struct InferCtxtInner<'tcx> { | |
| undo_log: InferCtxtUndoLogs<'tcx>, | |
| /// Cache for projections. | |
| /// | |
| /// This cache is snapshotted along with the infcx. | |
| projection_cache: traits::ProjectionCacheStorage<'tcx>, | |
| /// We instantiate `UnificationTable` with `bounds<Ty>` because the types | |
| /// that might instantiate a general type variable have an order, | |
| /// represented by its upper and lower bounds. | |
| type_variable_storage: type_variable::TypeVariableStorage<'tcx>, | |
| /// Map from const parameter variable to the kind of const it represents. | |
| const_unification_storage: ut::UnificationTableStorage<ConstVidKey<'tcx>>, | |
| /// Map from integral variable to the kind of integer it represents. | |
| int_unification_storage: ut::UnificationTableStorage<ty::IntVid>, | |
| /// Map from floating variable to the kind of float it represents. | |
| float_unification_storage: ut::UnificationTableStorage<ty::FloatVid>, | |
| /// Map from floating variable to the origin span it came from, and the HirId that should be | |
| /// used to lint at that location. This is only used for the FCW for the fallback to `f32`, | |
| /// so can be removed once the `f32` fallback is removed. | |
| float_origin_origin_storage: IndexVec<FloatVid, FloatVariableOrigin>, | |
| /// Tracks the set of region variables and the constraints between them. | |
| /// | |
| /// This is initially `Some(_)` but when | |
| /// `resolve_regions_and_report_errors` is invoked, this gets set to `None` | |
| /// -- further attempts to perform unification, etc., may fail if new | |
| /// region constraints would've been added. | |
| region_constraint_storage: Option<RegionConstraintStorage<'tcx>>, | |
| /// Used by the next solver when `-Zassumptions-on-binders` is set. | |
| solver_region_constraint_storage: SolverRegionConstraintStorage<'tcx>, | |
| /// A set of constraints that regionck must validate. | |
| /// | |
| /// Each constraint has the form `T:'a`, meaning "some type `T` must | |
| /// outlive the lifetime 'a". These constraints derive from | |
| /// instantiated type parameters. So if you had a struct defined | |
| /// like the following: | |
| /// ```ignore (illustrative) | |
| /// struct Foo<T: 'static> { ... } | |
| /// ``` | |
| /// In some expression `let x = Foo { ... }`, it will | |
| /// instantiate the type parameter `T` with a fresh type `$0`. At | |
| /// the same time, it will record a region obligation of | |
| /// `$0: 'static`. This will get checked later by regionck. (We | |
| /// can't generally check these things right away because we have | |
| /// to wait until types are resolved.) | |
| region_obligations: Vec<TypeOutlivesConstraint<'tcx>>, | |
| /// The outlives bounds that we assume must hold about placeholders that | |
| /// come from instantiating the binder of coroutine-witnesses. These bounds | |
| /// are deduced from the well-formedness of the witness's types, and are | |
| /// necessary because of the way we anonymize the regions in a coroutine, | |
| /// which may cause types to no longer be considered well-formed. | |
| region_assumptions: Vec<ty::ArgOutlivesPredicate<'tcx>>, | |
| /// `-Znext-solver`: Successfully proven goals during HIR typeck which | |
| /// reference inference variables and get reproven in case MIR type check | |
| /// fails to prove something. | |
| /// | |
| /// See the documentation of `InferCtxt::in_hir_typeck` for more details. | |
| hir_typeck_potentially_region_dependent_goals: Vec<PredicateObligation<'tcx>>, | |
| /// Caches for opaque type inference. | |
| opaque_type_storage: OpaqueTypeStorage<'tcx>, | |
| } | |
| impl<'tcx> InferCtxtInner<'tcx> { | |
| fn new() -> InferCtxtInner<'tcx> { | |
| InferCtxtInner { | |
| undo_log: InferCtxtUndoLogs::default(), | |
| projection_cache: Default::default(), | |
| type_variable_storage: Default::default(), | |
| const_unification_storage: Default::default(), | |
| int_unification_storage: Default::default(), | |
| float_unification_storage: Default::default(), | |
| float_origin_origin_storage: Default::default(), | |
| region_constraint_storage: Some(Default::default()), | |
| solver_region_constraint_storage: SolverRegionConstraintStorage::new(), | |
| region_obligations: Default::default(), | |
| region_assumptions: Default::default(), | |
| hir_typeck_potentially_region_dependent_goals: Default::default(), | |
| opaque_type_storage: Default::default(), | |
| } | |
| } | |
| #[inline] | |
| pub fn region_obligations(&self) -> &[TypeOutlivesConstraint<'tcx>] { | |
| &self.region_obligations | |
| } | |
| #[inline] | |
| pub fn region_assumptions(&self) -> &[ty::ArgOutlivesPredicate<'tcx>] { | |
| &self.region_assumptions | |
| } | |
| #[inline] | |
| pub fn projection_cache(&mut self) -> traits::ProjectionCache<'_, 'tcx> { | |
| self.projection_cache.with_log(&mut self.undo_log) | |
| } | |
| #[inline] | |
| fn try_type_variables_probe_ref( | |
| &self, | |
| vid: ty::TyVid, | |
| ) -> Option<&type_variable::TypeVariableValue<'tcx>> { | |
| // Uses a read-only view of the unification table, this way we don't | |
| // need an undo log. | |
| self.type_variable_storage.eq_relations_ref().try_probe_value(vid) | |
| } | |
| #[inline] | |
| fn type_variables(&mut self) -> type_variable::TypeVariableTable<'_, 'tcx> { | |
| self.type_variable_storage.with_log(&mut self.undo_log) | |
| } | |
| #[inline] | |
| pub fn opaque_types(&mut self) -> opaque_types::OpaqueTypeTable<'_, 'tcx> { | |
| self.opaque_type_storage.with_log(&mut self.undo_log) | |
| } | |
| #[inline] | |
| fn int_unification_table(&mut self) -> UnificationTable<'_, 'tcx, ty::IntVid> { | |
| self.int_unification_storage.with_log(&mut self.undo_log) | |
| } | |
| #[inline] | |
| fn float_unification_table(&mut self) -> UnificationTable<'_, 'tcx, ty::FloatVid> { | |
| self.float_unification_storage.with_log(&mut self.undo_log) | |
| } | |
| #[inline] | |
| fn const_unification_table(&mut self) -> UnificationTable<'_, 'tcx, ConstVidKey<'tcx>> { | |
| self.const_unification_storage.with_log(&mut self.undo_log) | |
| } | |
| #[inline] | |
| pub fn unwrap_region_constraints(&mut self) -> RegionConstraintCollector<'_, 'tcx> { | |
| self.region_constraint_storage | |
| .as_mut() | |
| .expect("region constraints already solved") | |
| .with_log(&mut self.undo_log) | |
| } | |
| } | |
| pub struct InferCtxt<'tcx> { | |
| pub tcx: TyCtxt<'tcx>, | |
| /// The mode of this inference context, see the struct documentation | |
| /// for more details. | |
| typing_mode: TypingMode<'tcx>, | |
| /// Whether this inference context should care about region obligations in | |
| /// the root universe. Most notably, this is used during HIR typeck as region | |
| /// solving is left to borrowck instead. | |
| /// | |
| /// This is used in the old solver to enable the generation of regions constraints. | |
| /// In the new solver its only used inside the InferCtxt's `Drop` implementation: | |
| /// if we're considering regions, and new opaques are registered, we panic. | |
| pub considering_regions: bool, | |
| /// `-Znext-solver`: Whether this inference context is used by HIR typeck. If so, we | |
| /// need to make sure we don't rely on region identity in the trait solver or when | |
| /// relating types. This is necessary as borrowck starts by replacing each occurrence of a | |
| /// free region with a unique inference variable. If HIR typeck ends up depending on two | |
| /// regions being equal we'd get unexpected mismatches between HIR typeck and MIR typeck, | |
| /// resulting in an ICE. | |
| /// | |
| /// The trait solver sometimes depends on regions being identical. As a concrete example | |
| /// the trait solver ignores other candidates if one candidate exists without any constraints. | |
| /// The goal `&'a u32: Equals<&'a u32>` has no constraints right now. If we replace each | |
| /// occurrence of `'a` with a unique region the goal now equates these regions. See | |
| /// the tests in trait-system-refactor-initiative#27 for concrete examples. | |
| /// | |
| /// We handle this by *uniquifying* region when canonicalizing root goals during HIR typeck. | |
| /// This is still insufficient as inference variables may *hide* region variables, so e.g. | |
| /// `dyn TwoSuper<?x, ?x>: Super<?x>` may hold but MIR typeck could end up having to prove | |
| /// `dyn TwoSuper<&'0 (), &'1 ()>: Super<&'2 ()>` which is now ambiguous. Because of this we | |
| /// stash all successfully proven goals which reference inference variables and then reprove | |
| /// them after writeback. | |
| pub in_hir_typeck: bool, | |
| /// If set, this flag causes us to skip the 'leak check' during | |
| /// higher-ranked subtyping operations. This flag is a temporary one used | |
| /// to manage the removal of the leak-check: for the time being, we still run the | |
| /// leak-check, but we issue warnings. | |
| skip_leak_check: bool, | |
| pub inner: RefCell<InferCtxtInner<'tcx>>, | |
| /// Once region inference is done, the values for each variable. | |
| lexical_region_resolutions: RefCell<Option<LexicalRegionResolutions<'tcx>>>, | |
| /// Caches the results of trait selection. This cache is used | |
| /// for things that depends on inference variables or placeholders. | |
| pub selection_cache: select::SelectionCache<'tcx, ty::ParamEnv<'tcx>>, | |
| /// Caches the results of trait evaluation. This cache is used | |
| /// for things that depends on inference variables or placeholders. | |
| pub evaluation_cache: select::EvaluationCache<'tcx, ty::ParamEnv<'tcx>>, | |
| /// The set of predicates on which errors have been reported, to | |
| /// avoid reporting the same error twice. | |
| pub reported_trait_errors: | |
| RefCell<FxIndexMap<Span, (Vec<Goal<'tcx, ty::Predicate<'tcx>>>, ErrorGuaranteed)>>, | |
| pub reported_signature_mismatch: RefCell<FxHashSet<(Span, Option<Span>)>>, | |
| /// When an error occurs, we want to avoid reporting "derived" | |
| /// errors that are due to this original failure. We have this | |
| /// flag that one can set whenever one creates a type-error that | |
| /// is due to an error in a prior pass. | |
| /// | |
| /// Don't read this flag directly, call `is_tainted_by_errors()` | |
| /// and `set_tainted_by_errors()`. | |
| tainted_by_errors: Cell<Option<ErrorGuaranteed>>, | |
| /// What is the innermost universe we have created? Starts out as | |
| /// `UniverseIndex::root()` but grows from there as we enter | |
| /// universal quantifiers. | |
| /// | |
| /// N.B., at present, we exclude the universal quantifiers on the | |
| /// item we are type-checking, and just consider those names as | |
| /// part of the root universe. So this would only get incremented | |
| /// when we enter into a higher-ranked (`for<..>`) type or trait | |
| /// bound. | |
| universe: Cell<ty::UniverseIndex>, | |
| /// List of assumed wellformed types which we can derive implied | |
| /// bounds on a `for<...>` from. Only used unstabley and by the | |
| /// new solver. | |
| // | |
| // FIXME(-Zassumptions-on-binders): This and `universe` should probably be | |
| // in `InferCtxtInner` so they can participate in rollbacks and whatnot | |
| placeholder_assumptions_for_next_solver: RefCell< | |
| FxIndexMap< | |
| ty::UniverseIndex, | |
| Option<rustc_type_ir::region_constraint::Assumptions<TyCtxt<'tcx>>>, | |
| >, | |
| >, | |
| next_trait_solver: bool, | |
| pub obligation_inspector: Cell<Option<ObligationInspector<'tcx>>>, | |
| } | |
| impl<'tcx> Drop for InferCtxt<'tcx> { | |
| fn drop(&mut self) { | |
| let mut inner = self.inner.borrow_mut(); | |
| let opaque_type_storage = &mut inner.opaque_type_storage; | |
| // No need for the drop bomb when we're in `TypingMode::PostTypeckUntilBorrowck`, and the `InferCtxt` | |
| // doesn't consider regions. This is okay since after typeck, the only reason we care about opaques is | |
| // in relation to regions. In some places *after* typeck that aren't borrowck, like in lints we use | |
| // `TypingMode::PostTypeckUntilBorrowck` to prevent defining opaque types and we simply don't care about regions. | |
| match self.typing_mode_raw() { | |
| TypingMode::Coherence | |
| | TypingMode::Typeck { .. } | |
| | TypingMode::PostBorrowck { .. } | |
| | TypingMode::PostAnalysis | |
| | TypingMode::Codegen => {} | |
| // In erased mode, the opaque type storage is always empty | |
| TypingMode::ErasedNotCoherence(..) => {} | |
| TypingMode::PostTypeckUntilBorrowck { .. } => { | |
| if !self.considering_regions { | |
| return; | |
| } | |
| } | |
| } | |
| if !opaque_type_storage.is_empty() { | |
| ty::tls::with(|tcx| tcx.dcx().delayed_bug(format!("{opaque_type_storage:?}"))); | |
| } | |
| } | |
| } | |
| /// See the `error_reporting` module for more details. | |
| #[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable)] | |
| pub enum ValuePairs<'tcx> { | |
| Regions(ExpectedFound<ty::Region<'tcx>>), | |
| Terms(ExpectedFound<ty::Term<'tcx>>), | |
| Aliases(ExpectedFound<ty::AliasTerm<'tcx>>), | |
| TraitRefs(ExpectedFound<ty::TraitRef<'tcx>>), | |
| PolySigs(ExpectedFound<ty::PolyFnSig<'tcx>>), | |
| ExistentialTraitRef(ExpectedFound<ty::PolyExistentialTraitRef<'tcx>>), | |
| ExistentialProjection(ExpectedFound<ty::PolyExistentialProjection<'tcx>>), | |
| } | |
| impl<'tcx> ValuePairs<'tcx> { | |
| pub fn ty(&self) -> Option<(Ty<'tcx>, Ty<'tcx>)> { | |
| if let ValuePairs::Terms(ExpectedFound { expected, found }) = self | |
| && let Some(expected) = expected.as_type() | |
| && let Some(found) = found.as_type() | |
| { | |
| Some((expected, found)) | |
| } else { | |
| None | |
| } | |
| } | |
| } | |
| /// The trace designates the path through inference that we took to | |
| /// encounter an error or subtyping constraint. | |
| /// | |
| /// See the `error_reporting` module for more details. | |
| #[derive(Clone, Debug)] | |
| pub struct TypeTrace<'tcx> { | |
| pub cause: ObligationCause<'tcx>, | |
| pub values: ValuePairs<'tcx>, | |
| } | |
| /// The origin of a `r1 <= r2` constraint. | |
| /// | |
| /// See `error_reporting` module for more details | |
| #[derive(Clone, Debug)] | |
| pub enum SubregionOrigin<'tcx> { | |
| /// Arose from a subtyping relation | |
| Subtype(Box<TypeTrace<'tcx>>), | |
| /// When casting `&'a T` to an `&'b Trait` object, | |
| /// relating `'a` to `'b`. | |
| RelateObjectBound(Span), | |
| /// Some type parameter was instantiated with the given type, | |
| /// and that type must outlive some region. | |
| RelateParamBound(Span, Ty<'tcx>, Option<Span>), | |
| /// The given region parameter was instantiated with a region | |
| /// that must outlive some other region. | |
| RelateRegionParamBound(Span, Option<Ty<'tcx>>), | |
| /// Creating a pointer `b` to contents of another reference. | |
| Reborrow(Span), | |
| /// (&'a &'b T) where a >= b | |
| ReferenceOutlivesReferent(Ty<'tcx>, Span), | |
| /// Comparing the signature and requirements of an impl method against | |
| /// the containing trait. | |
| CompareImplItemObligation { | |
| span: Span, | |
| impl_item_def_id: LocalDefId, | |
| trait_item_def_id: DefId, | |
| }, | |
| /// Checking that the bounds of a trait's associated type hold for a given impl. | |
| CheckAssociatedTypeBounds { | |
| parent: Box<SubregionOrigin<'tcx>>, | |
| impl_item_def_id: LocalDefId, | |
| trait_item_def_id: DefId, | |
| }, | |
| AscribeUserTypeProvePredicate(Span), | |
| // FIXME(-Zassumptions-on-binders): this is a temporary hack until we support | |
| // proper diagnostics for solver region constraints. | |
| SolverRegionConstraint(Span), | |
| } | |
| // `SubregionOrigin` is used a lot. Make sure it doesn't unintentionally get bigger. | |
| #[cfg(target_pointer_width = "64")] | |
| rustc_data_structures::static_assert_size!(SubregionOrigin<'_>, 32); | |
| impl<'tcx> SubregionOrigin<'tcx> { | |
| pub fn to_constraint_category(&self) -> ConstraintCategory<'tcx> { | |
| match self { | |
| Self::Subtype(type_trace) => type_trace.cause.to_constraint_category(), | |
| Self::AscribeUserTypeProvePredicate(span) => ConstraintCategory::Predicate(*span), | |
| Self::SolverRegionConstraint(span) => ConstraintCategory::SolverRegionConstraint(*span), | |
| _ => ConstraintCategory::BoringNoLocation, | |
| } | |
| } | |
| } | |
| /// Times when we replace bound regions with existentials: | |
| #[derive(Clone, Copy, Debug)] | |
| pub enum BoundRegionConversionTime { | |
| /// when a fn is called | |
| FnCall, | |
| /// when two higher-ranked types are compared | |
| HigherRankedType, | |
| /// when projecting an associated type | |
| AssocTypeProjection(DefId), | |
| } | |
| /// Reasons to create a region inference variable. | |
| /// | |
| /// See `error_reporting` module for more details. | |
| #[derive(Copy, Clone, Debug)] | |
| pub enum RegionVariableOrigin<'tcx> { | |
| /// Region variables created for ill-categorized reasons. | |
| /// | |
| /// They mostly indicate places in need of refactoring. | |
| Misc(Span), | |
| /// Regions created by a `&P` or `[...]` pattern. | |
| PatternRegion(Span), | |
| /// Regions created by `&` operator. | |
| BorrowRegion(Span), | |
| /// Regions created as part of an autoref of a method receiver. | |
| Autoref(Span), | |
| /// Regions created as part of an automatic coercion. | |
| Coercion(Span), | |
| /// Region variables created as the values for early-bound regions. | |
| /// | |
| /// FIXME(@lcnr): This should also store a `DefId`, similar to | |
| /// `TypeVariableOrigin`. | |
| RegionParameterDefinition(Span, Symbol), | |
| /// Region variables created when instantiating a binder with | |
| /// existential variables, e.g. when calling a function or method. | |
| BoundRegion(Span, ty::BoundRegionKind<'tcx>, BoundRegionConversionTime), | |
| UpvarRegion(ty::UpvarId, Span), | |
| /// This origin is used for the inference variables that we create | |
| /// during NLL region processing. | |
| Nll(NllRegionVariableOrigin<'tcx>), | |
| } | |
| #[derive(Copy, Clone, Debug)] | |
| pub enum NllRegionVariableOrigin<'tcx> { | |
| /// During NLL region processing, we create variables for free | |
| /// regions that we encounter in the function signature and | |
| /// elsewhere. This origin indices we've got one of those. | |
| FreeRegion, | |
| /// "Universal" instantiation of a higher-ranked region (e.g., | |
| /// from a `for<'a> T` binder). Meant to represent "any region". | |
| Placeholder(ty::PlaceholderRegion<'tcx>), | |
| Existential { | |
| name: Option<Symbol>, | |
| }, | |
| } | |
| #[derive(Copy, Clone, Debug)] | |
| pub struct FixupError { | |
| unresolved: TyOrConstInferVar, | |
| } | |
| impl fmt::Display for FixupError { | |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
| match self.unresolved { | |
| TyOrConstInferVar::TyInt(_) => write!( | |
| f, | |
| "cannot determine the type of this integer; \ | |
| add a suffix to specify the type explicitly" | |
| ), | |
| TyOrConstInferVar::TyFloat(_) => write!( | |
| f, | |
| "cannot determine the type of this number; \ | |
| add a suffix to specify the type explicitly" | |
| ), | |
| TyOrConstInferVar::Ty(_) => write!(f, "unconstrained type"), | |
| TyOrConstInferVar::Const(_) => write!(f, "unconstrained const value"), | |
| } | |
| } | |
| } | |
| /// See the `region_obligations` field for more information. | |
| #[derive(Clone, Debug)] | |
| pub struct TypeOutlivesConstraint<'tcx> { | |
| pub sub_region: ty::Region<'tcx>, | |
| pub sup_type: Ty<'tcx>, | |
| pub origin: SubregionOrigin<'tcx>, | |
| } | |
| /// Used to configure inference contexts before their creation. | |
| pub struct InferCtxtBuilder<'tcx> { | |
| tcx: TyCtxt<'tcx>, | |
| considering_regions: bool, | |
| in_hir_typeck: bool, | |
| skip_leak_check: bool, | |
| /// Whether we should use the new trait solver in the local inference context, | |
| /// which affects things like which solver is used in `predicate_may_hold`. | |
| next_trait_solver: bool, | |
| } | |
| #[extension(pub trait TyCtxtInferExt<'tcx>)] | |
| impl<'tcx> TyCtxt<'tcx> { | |
| fn infer_ctxt(self) -> InferCtxtBuilder<'tcx> { | |
| InferCtxtBuilder { | |
| tcx: self, | |
| considering_regions: true, | |
| in_hir_typeck: false, | |
| skip_leak_check: false, | |
| next_trait_solver: self.next_trait_solver_globally(), | |
| } | |
| } | |
| } | |
| impl<'tcx> InferCtxtBuilder<'tcx> { | |
| pub fn with_next_trait_solver(mut self, next_trait_solver: bool) -> Self { | |
| self.next_trait_solver = next_trait_solver; | |
| self | |
| } | |
| pub fn ignoring_regions(mut self) -> Self { | |
| self.considering_regions = false; | |
| self | |
| } | |
| pub fn in_hir_typeck(mut self) -> Self { | |
| self.in_hir_typeck = true; | |
| self | |
| } | |
| pub fn skip_leak_check(mut self, skip_leak_check: bool) -> Self { | |
| self.skip_leak_check = skip_leak_check; | |
| self | |
| } | |
| /// Given a canonical value `C` as a starting point, create an | |
| /// inference context that contains each of the bound values | |
| /// within instantiated as a fresh variable. The `f` closure is | |
| /// invoked with the new infcx, along with the instantiated value | |
| /// `V` and a instantiation `S`. This instantiation `S` maps from | |
| /// the bound values in `C` to their instantiated values in `V` | |
| /// (in other words, `S(C) = V`). | |
| pub fn build_with_canonical<T>( | |
| mut self, | |
| span: Span, | |
| input: &CanonicalQueryInput<'tcx, T>, | |
| ) -> (InferCtxt<'tcx>, T, CanonicalVarValues<'tcx>) | |
| where | |
| T: TypeFoldable<TyCtxt<'tcx>>, | |
| { | |
| let infcx = self.build(input.typing_mode.0); | |
| let (value, args) = infcx.instantiate_canonical(span, &input.canonical); | |
| (infcx, value, args) | |
| } | |
| pub fn build_with_typing_env( | |
| mut self, | |
| typing_env: TypingEnv<'tcx>, | |
| ) -> (InferCtxt<'tcx>, ty::ParamEnv<'tcx>) { | |
| (self.build(typing_env.typing_mode()), typing_env.param_env) | |
| } | |
| pub fn build(&mut self, typing_mode: TypingMode<'tcx>) -> InferCtxt<'tcx> { | |
| let InferCtxtBuilder { | |
| tcx, | |
| considering_regions, | |
| in_hir_typeck, | |
| skip_leak_check, | |
| next_trait_solver, | |
| } = *self; | |
| InferCtxt { | |
| tcx, | |
| typing_mode, | |
| considering_regions, | |
| in_hir_typeck, | |
| skip_leak_check, | |
| inner: RefCell::new(InferCtxtInner::new()), | |
| lexical_region_resolutions: RefCell::new(None), | |
| selection_cache: Default::default(), | |
| evaluation_cache: Default::default(), | |
| reported_trait_errors: Default::default(), | |
| reported_signature_mismatch: Default::default(), | |
| tainted_by_errors: Cell::new(None), | |
| universe: Cell::new(ty::UniverseIndex::ROOT), | |
| placeholder_assumptions_for_next_solver: RefCell::new(Default::default()), | |
| next_trait_solver, | |
| obligation_inspector: Cell::new(None), | |
| } | |
| } | |
| } | |
| impl<'tcx, T> InferOk<'tcx, T> { | |
| /// Extracts `value`, registering any obligations into `fulfill_cx`. | |
| pub fn into_value_registering_obligations<E: 'tcx>( | |
| self, | |
| infcx: &InferCtxt<'tcx>, | |
| fulfill_cx: &mut dyn TraitEngine<'tcx, E>, | |
| ) -> T { | |
| let InferOk { value, obligations } = self; | |
| fulfill_cx.register_predicate_obligations(infcx, obligations); | |
| value | |
| } | |
| } | |
| impl<'tcx> InferOk<'tcx, ()> { | |
| pub fn into_obligations(self) -> PredicateObligations<'tcx> { | |
| self.obligations | |
| } | |
| } | |
| impl<'tcx> InferCtxt<'tcx> { | |
| pub fn dcx(&self) -> DiagCtxtHandle<'_> { | |
| self.tcx.dcx().taintable_handle(&self.tainted_by_errors) | |
| } | |
| pub fn next_trait_solver(&self) -> bool { | |
| self.next_trait_solver | |
| } | |
| /// This method is deliberately called `..._raw`, | |
| /// since the output may possibly include [`TypingMode::ErasedNotCoherence`](TypingMode::ErasedNotCoherence). | |
| /// `ErasedNotCoherence` is an implementation detail of the next trait solver, see its docs for | |
| /// more information. | |
| /// | |
| /// `InferCtxt` has two uses: the trait solver calls some methods on it, because the `InferCtxt` | |
| /// works as a kind of store for for example type unification information. | |
| /// `InferCtxt` is also often used outside the trait solver during typeck. | |
| /// There, we don't care about the `ErasedNotCoherence` case and should never encounter it. | |
| /// To make sure these two uses are never confused, we want to statically encode this information. | |
| /// | |
| /// The `FnCtxt`, for example, is only used in the outside-trait-solver case. It has a non-raw | |
| /// version of the `typing_mode` method available that asserts `ErasedNotCoherence` is | |
| /// impossible, and returns a `TypingMode` where `ErasedNotCoherence` is made uninhabited using | |
| /// the [`CantBeErased`](rustc_type_ir::CantBeErased) enum. That way you don't even have to | |
| /// match on the variant and can safely ignore it. | |
| /// | |
| /// Prefer non-raw apis if available. e.g., | |
| /// - On the `FnCtxt` | |
| /// - on the `SelectionCtxt` | |
| #[inline(always)] | |
| pub fn typing_mode_raw(&self) -> TypingMode<'tcx> { | |
| self.typing_mode | |
| } | |
| #[inline(always)] | |
| pub fn disable_trait_solver_fast_paths(&self) -> bool { | |
| self.tcx.disable_trait_solver_fast_paths() | |
| } | |
| /// Returns the origin of the type variable identified by `vid`. | |
| /// | |
| /// No attempt is made to resolve `vid` to its root variable. | |
| pub fn type_var_origin(&self, vid: TyVid) -> TypeVariableOrigin { | |
| self.inner.borrow_mut().type_variables().var_origin(vid) | |
| } | |
| /// Returns the origin of the float type variable identified by `vid`. | |
| /// | |
| /// No attempt is made to resolve `vid` to its root variable. | |
| pub fn float_var_origin(&self, vid: FloatVid) -> FloatVariableOrigin { | |
| self.inner.borrow_mut().float_origin_origin_storage[vid] | |
| } | |
| /// Returns the origin of the const variable identified by `vid` | |
| // FIXME: We should store origins separately from the unification table | |
| // so this doesn't need to be optional. | |
| pub fn const_var_origin(&self, vid: ConstVid) -> Option<ConstVariableOrigin> { | |
| match self.inner.borrow_mut().const_unification_table().probe_value(vid) { | |
| ConstVariableValue::Known { .. } => None, | |
| ConstVariableValue::Unknown { origin, .. } => Some(origin), | |
| } | |
| } | |
| pub fn unresolved_variables(&self) -> Vec<Ty<'tcx>> { | |
| let mut inner = self.inner.borrow_mut(); | |
| let mut vars: Vec<Ty<'_>> = inner | |
| .type_variables() | |
| .unresolved_variables() | |
| .into_iter() | |
| .map(|t| Ty::new_var(self.tcx, t)) | |
| .collect(); | |
| vars.extend( | |
| (0..inner.int_unification_table().len()) | |
| .map(|i| ty::IntVid::from_usize(i)) | |
| .filter(|&vid| inner.int_unification_table().probe_value(vid).is_unknown()) | |
| .map(|v| Ty::new_int_var(self.tcx, v)), | |
| ); | |
| vars.extend( | |
| (0..inner.float_unification_table().len()) | |
| .map(|i| ty::FloatVid::from_usize(i)) | |
| .filter(|&vid| inner.float_unification_table().probe_value(vid).is_unknown()) | |
| .map(|v| Ty::new_float_var(self.tcx, v)), | |
| ); | |
| vars | |
| } | |
| #[instrument(skip(self), level = "debug")] | |
| pub fn sub_regions( | |
| &self, | |
| origin: SubregionOrigin<'tcx>, | |
| a: ty::Region<'tcx>, | |
| b: ty::Region<'tcx>, | |
| vis: ty::VisibleForLeakCheck, | |
| ) { | |
| self.inner.borrow_mut().unwrap_region_constraints().make_subregion(origin, a, b, vis); | |
| } | |
| #[instrument(skip(self), level = "debug")] | |
| pub fn equate_regions( | |
| &self, | |
| origin: SubregionOrigin<'tcx>, | |
| a: ty::Region<'tcx>, | |
| b: ty::Region<'tcx>, | |
| vis: ty::VisibleForLeakCheck, | |
| ) { | |
| self.inner.borrow_mut().unwrap_region_constraints().make_eqregion(origin, a, b, vis); | |
| } | |
| /// Processes a `Coerce` predicate from the fulfillment context. | |
| /// This is NOT the preferred way to handle coercion, which is to | |
| /// invoke `FnCtxt::coerce` or a similar method (see `coercion.rs`). | |
| /// | |
| /// This method here is actually a fallback that winds up being | |
| /// invoked when `FnCtxt::coerce` encounters unresolved type variables | |
| /// and records a coercion predicate. Presently, this method is equivalent | |
| /// to `subtype_predicate` -- that is, "coercing" `a` to `b` winds up | |
| /// actually requiring `a <: b`. This is of course a valid coercion, | |
| /// but it's not as flexible as `FnCtxt::coerce` would be. | |
| /// | |
| /// (We may refactor this in the future, but there are a number of | |
| /// practical obstacles. Among other things, `FnCtxt::coerce` presently | |
| /// records adjustments that are required on the HIR in order to perform | |
| /// the coercion, and we don't currently have a way to manage that.) | |
| pub fn coerce_predicate( | |
| &self, | |
| cause: &ObligationCause<'tcx>, | |
| param_env: ty::ParamEnv<'tcx>, | |
| predicate: ty::PolyCoercePredicate<'tcx>, | |
| ) -> Result<InferResult<'tcx, ()>, (TyVid, TyVid)> { | |
| let subtype_predicate = predicate.map_bound(|p| ty::SubtypePredicate { | |
| a_is_expected: false, // when coercing from `a` to `b`, `b` is expected | |
| a: p.a, | |
| b: p.b, | |
| }); | |
| self.subtype_predicate(cause, param_env, subtype_predicate) | |
| } | |
| pub fn subtype_predicate( | |
| &self, | |
| cause: &ObligationCause<'tcx>, | |
| param_env: ty::ParamEnv<'tcx>, | |
| predicate: ty::PolySubtypePredicate<'tcx>, | |
| ) -> Result<InferResult<'tcx, ()>, (TyVid, TyVid)> { | |
| // Check for two unresolved inference variables, in which case we can | |
| // make no progress. This is partly a micro-optimization, but it's | |
| // also an opportunity to "sub-unify" the variables. This isn't | |
| // *necessary* to prevent cycles, because they would eventually be sub-unified | |
| // anyhow during generalization, but it helps with diagnostics (we can detect | |
| // earlier that they are sub-unified). | |
| // | |
| // Note that we can just skip the binders here because | |
| // type variables can't (at present, at | |
| // least) capture any of the things bound by this binder. | |
| // | |
| // Note that this sub here is not just for diagnostics - it has semantic | |
| // effects as well. | |
| let r_a = self.shallow_resolve(predicate.skip_binder().a); | |
| let r_b = self.shallow_resolve(predicate.skip_binder().b); | |
| match (r_a.kind(), r_b.kind()) { | |
| (&ty::Infer(ty::TyVar(a_vid)), &ty::Infer(ty::TyVar(b_vid))) => { | |
| self.sub_unify_ty_vids_raw(a_vid, b_vid); | |
| return Err((a_vid, b_vid)); | |
| } | |
| _ => {} | |
| } | |
| self.enter_forall(predicate, |ty::SubtypePredicate { a_is_expected, a, b }| { | |
| if a_is_expected { | |
| Ok(self.at(cause, param_env).sub(DefineOpaqueTypes::Yes, a, b)) | |
| } else { | |
| Ok(self.at(cause, param_env).sup(DefineOpaqueTypes::Yes, b, a)) | |
| } | |
| }) | |
| } | |
| /// Number of type variables created so far. | |
| pub fn num_ty_vars(&self) -> usize { | |
| self.inner.borrow_mut().type_variables().num_vars() | |
| } | |
| pub fn next_ty_vid(&self, span: Span) -> TyVid { | |
| self.next_ty_vid_with_origin(TypeVariableOrigin { span, param_def_id: None }) | |
| } | |
| pub fn next_ty_vid_with_origin(&self, origin: TypeVariableOrigin) -> TyVid { | |
| self.inner.borrow_mut().type_variables().new_var(self.universe(), origin) | |
| } | |
| pub fn next_ty_vid_in_universe(&self, span: Span, universe: ty::UniverseIndex) -> TyVid { | |
| let origin = TypeVariableOrigin { span, param_def_id: None }; | |
| self.inner.borrow_mut().type_variables().new_var(universe, origin) | |
| } | |
| pub fn next_ty_var(&self, span: Span) -> Ty<'tcx> { | |
| self.next_ty_var_with_origin(TypeVariableOrigin { span, param_def_id: None }) | |
| } | |
| pub fn next_ty_var_with_origin(&self, origin: TypeVariableOrigin) -> Ty<'tcx> { | |
| let vid = self.next_ty_vid_with_origin(origin); | |
| Ty::new_var(self.tcx, vid) | |
| } | |
| pub fn next_ty_var_in_universe(&self, span: Span, universe: ty::UniverseIndex) -> Ty<'tcx> { | |
| let vid = self.next_ty_vid_in_universe(span, universe); | |
| Ty::new_var(self.tcx, vid) | |
| } | |
| pub fn next_const_var(&self, span: Span) -> ty::Const<'tcx> { | |
| self.next_const_var_with_origin(ConstVariableOrigin { span, param_def_id: None }) | |
| } | |
| pub fn next_const_var_with_origin(&self, origin: ConstVariableOrigin) -> ty::Const<'tcx> { | |
| let vid = self | |
| .inner | |
| .borrow_mut() | |
| .const_unification_table() | |
| .new_key(ConstVariableValue::Unknown { origin, universe: self.universe() }) | |
| .vid; | |
| ty::Const::new_var(self.tcx, vid) | |
| } | |
| pub fn next_const_var_in_universe( | |
| &self, | |
| span: Span, | |
| universe: ty::UniverseIndex, | |
| ) -> ty::Const<'tcx> { | |
| let origin = ConstVariableOrigin { span, param_def_id: None }; | |
| let vid = self | |
| .inner | |
| .borrow_mut() | |
| .const_unification_table() | |
| .new_key(ConstVariableValue::Unknown { origin, universe }) | |
| .vid; | |
| ty::Const::new_var(self.tcx, vid) | |
| } | |
| pub fn next_int_var(&self) -> Ty<'tcx> { | |
| let next_int_var_id = | |
| self.inner.borrow_mut().int_unification_table().new_key(ty::IntVarValue::Unknown); | |
| Ty::new_int_var(self.tcx, next_int_var_id) | |
| } | |
| pub fn next_float_var(&self, span: Span, lint_id: Option<HirId>) -> Ty<'tcx> { | |
| let mut inner = self.inner.borrow_mut(); | |
| let next_float_var_id = inner.float_unification_table().new_key(ty::FloatVarValue::Unknown); | |
| let origin = FloatVariableOrigin { span, lint_id }; | |
| let span_index = inner.float_origin_origin_storage.push(origin); | |
| debug_assert_eq!(next_float_var_id, span_index); | |
| Ty::new_float_var(self.tcx, next_float_var_id) | |
| } | |
| /// Creates a fresh region variable with the next available index. | |
| /// The variable will be created in the maximum universe created | |
| /// thus far, allowing it to name any region created thus far. | |
| pub fn next_region_var(&self, origin: RegionVariableOrigin<'tcx>) -> ty::Region<'tcx> { | |
| self.next_region_var_in_universe(origin, self.universe()) | |
| } | |
| /// Creates a fresh region variable with the next available index | |
| /// in the given universe; typically, you can use | |
| /// `next_region_var` and just use the maximal universe. | |
| pub fn next_region_var_in_universe( | |
| &self, | |
| origin: RegionVariableOrigin<'tcx>, | |
| universe: ty::UniverseIndex, | |
| ) -> ty::Region<'tcx> { | |
| let region_var = | |
| self.inner.borrow_mut().unwrap_region_constraints().new_region_var(universe, origin); | |
| ty::Region::new_var(self.tcx, region_var) | |
| } | |
| pub fn next_term_var_of_alias_kind( | |
| &self, | |
| alias_term: ty::AliasTerm<'tcx>, | |
| span: Span, | |
| ) -> ty::Term<'tcx> { | |
| match alias_term.kind { | |
| ty::AliasTermKind::ProjectionTy { .. } | |
| | ty::AliasTermKind::InherentTy { .. } | |
| | ty::AliasTermKind::OpaqueTy { .. } | |
| | ty::AliasTermKind::FreeTy { .. } => self.next_ty_var(span).into(), | |
| ty::AliasTermKind::FreeConst { .. } | |
| | ty::AliasTermKind::InherentConst { .. } | |
| | ty::AliasTermKind::AnonConst { .. } | |
| | ty::AliasTermKind::ProjectionConst { .. } => self.next_const_var(span).into(), | |
| } | |
| } | |
| /// Return the universe that the region `r` was created in. For | |
| /// most regions (e.g., `'static`, named regions from the user, | |
| /// etc) this is the root universe U0. For inference variables or | |
| /// placeholders, however, it will return the universe which they | |
| /// are associated. | |
| pub fn universe_of_region(&self, r: ty::Region<'tcx>) -> ty::UniverseIndex { | |
| self.inner.borrow_mut().unwrap_region_constraints().universe(r) | |
| } | |
| /// Number of region variables created so far. | |
| pub fn num_region_vars(&self) -> usize { | |
| self.inner.borrow_mut().unwrap_region_constraints().num_region_vars() | |
| } | |
| /// Just a convenient wrapper of `next_region_var` for using during NLL. | |
| #[instrument(skip(self), level = "debug")] | |
| pub fn next_nll_region_var(&self, origin: NllRegionVariableOrigin<'tcx>) -> ty::Region<'tcx> { | |
| self.next_region_var(RegionVariableOrigin::Nll(origin)) | |
| } | |
| /// Just a convenient wrapper of `next_region_var` for using during NLL. | |
| #[instrument(skip(self), level = "debug")] | |
| pub fn next_nll_region_var_in_universe( | |
| &self, | |
| origin: NllRegionVariableOrigin<'tcx>, | |
| universe: ty::UniverseIndex, | |
| ) -> ty::Region<'tcx> { | |
| self.next_region_var_in_universe(RegionVariableOrigin::Nll(origin), universe) | |
| } | |
| pub fn var_for_def(&self, span: Span, param: &ty::GenericParamDef) -> GenericArg<'tcx> { | |
| match param.kind { | |
| GenericParamDefKind::Lifetime => { | |
| // Create a region inference variable for the given | |
| // region parameter definition. | |
| self.next_region_var(RegionVariableOrigin::RegionParameterDefinition( | |
| span, param.name, | |
| )) | |
| .into() | |
| } | |
| GenericParamDefKind::Type { .. } => { | |
| // Create a type inference variable for the given | |
| // type parameter definition. The generic parameters are | |
| // for actual parameters that may be referred to by | |
| // the default of this type parameter, if it exists. | |
| // e.g., `struct Foo<A, B, C = (A, B)>(...);` when | |
| // used in a path such as `Foo::<T, U>::new()` will | |
| // use an inference variable for `C` with `[T, U]` | |
| // as the generic parameters for the default, `(T, U)`. | |
| let ty_var_id = self.inner.borrow_mut().type_variables().new_var( | |
| self.universe(), | |
| TypeVariableOrigin { param_def_id: Some(param.def_id), span }, | |
| ); | |
| Ty::new_var(self.tcx, ty_var_id).into() | |
| } | |
| GenericParamDefKind::Const { .. } => { | |
| let origin = ConstVariableOrigin { param_def_id: Some(param.def_id), span }; | |
| let const_var_id = self | |
| .inner | |
| .borrow_mut() | |
| .const_unification_table() | |
| .new_key(ConstVariableValue::Unknown { origin, universe: self.universe() }) | |
| .vid; | |
| ty::Const::new_var(self.tcx, const_var_id).into() | |
| } | |
| } | |
| } | |
| /// Given a set of generics defined on a type or impl, returns the generic parameters mapping | |
| /// each type/region parameter to a fresh inference variable. | |
| pub fn fresh_args_for_item(&self, span: Span, def_id: DefId) -> GenericArgsRef<'tcx> { | |
| GenericArgs::for_item(self.tcx, def_id, |param, _| self.var_for_def(span, param)) | |
| } | |
| /// Returns `true` if errors have been reported since this infcx was | |
| /// created. This is sometimes used as a heuristic to skip | |
| /// reporting errors that often occur as a result of earlier | |
| /// errors, but where it's hard to be 100% sure (e.g., unresolved | |
| /// inference variables, regionck errors). | |
| #[must_use = "this method does not have any side effects"] | |
| pub fn tainted_by_errors(&self) -> Option<ErrorGuaranteed> { | |
| self.tainted_by_errors.get() | |
| } | |
| /// Set the "tainted by errors" flag to true. We call this when we | |
| /// observe an error from a prior pass. | |
| pub fn set_tainted_by_errors(&self, e: ErrorGuaranteed) { | |
| debug!("set_tainted_by_errors(ErrorGuaranteed)"); | |
| self.tainted_by_errors.set(Some(e)); | |
| } | |
| pub fn region_var_origin(&self, vid: ty::RegionVid) -> RegionVariableOrigin<'tcx> { | |
| let mut inner = self.inner.borrow_mut(); | |
| let inner = &mut *inner; | |
| inner.unwrap_region_constraints().var_origin(vid) | |
| } | |
| /// Clone the list of variable regions. This is used only during NLL processing | |
| /// to put the set of region variables into the NLL region context. | |
| pub fn get_region_var_infos(&self) -> VarInfos<'tcx> { | |
| let inner = self.inner.borrow(); | |
| assert!(!UndoLogs::<UndoLog<'_>>::in_snapshot(&inner.undo_log)); | |
| let storage = inner.region_constraint_storage.as_ref().expect("regions already resolved"); | |
| assert!(storage.data.is_empty(), "{:#?}", storage.data); | |
| // We clone instead of taking because borrowck still wants to use the | |
| // inference context after calling this for diagnostics and the new | |
| // trait solver. | |
| storage.var_infos.clone() | |
| } | |
| pub fn has_opaque_types_in_storage(&self) -> bool { | |
| !self.inner.borrow().opaque_type_storage.is_empty() | |
| } | |
| #[instrument(level = "debug", skip(self), ret)] | |
| pub fn take_opaque_types(&self) -> Vec<(OpaqueTypeKey<'tcx>, ProvisionalHiddenType<'tcx>)> { | |
| self.inner.borrow_mut().opaque_type_storage.take_opaque_types().collect() | |
| } | |
| #[instrument(level = "debug", skip(self), ret)] | |
| pub fn clone_opaque_types(&self) -> Vec<(OpaqueTypeKey<'tcx>, ProvisionalHiddenType<'tcx>)> { | |
| self.inner.borrow_mut().opaque_type_storage.iter_opaque_types().collect() | |
| } | |
| pub fn has_opaques_with_sub_unified_hidden_type(&self, ty_vid: TyVid) -> bool { | |
| if !self.next_trait_solver() { | |
| return false; | |
| } | |
| let ty_sub_vid = self.sub_unification_table_root_var(ty_vid); | |
| let inner = &mut *self.inner.borrow_mut(); | |
| let mut type_variables = inner.type_variable_storage.with_log(&mut inner.undo_log); | |
| inner.opaque_type_storage.iter_opaque_types().any(|(_, hidden_ty)| { | |
| if let ty::Infer(ty::TyVar(hidden_vid)) = *hidden_ty.ty.kind() { | |
| let opaque_sub_vid = type_variables.sub_unification_table_root_var(hidden_vid); | |
| if opaque_sub_vid == ty_sub_vid { | |
| return true; | |
| } | |
| } | |
| false | |
| }) | |
| } | |
| /// Searches for an opaque type key whose hidden type is related to `ty_vid`. | |
| /// | |
| /// This only checks for a subtype relation, it does not require equality. | |
| pub fn opaques_with_sub_unified_hidden_type( | |
| &self, | |
| ty_vid: TyVid, | |
| ) -> Vec<ty::OpaqueAliasTy<'tcx>> { | |
| // Avoid accidentally allowing more code to compile with the old solver. | |
| if !self.next_trait_solver() { | |
| return vec![]; | |
| } | |
| let ty_sub_vid = self.sub_unification_table_root_var(ty_vid); | |
| let inner = &mut *self.inner.borrow_mut(); | |
| // This is iffy, can't call `type_variables()` as we're already | |
| // borrowing the `opaque_type_storage` here. | |
| let mut type_variables = inner.type_variable_storage.with_log(&mut inner.undo_log); | |
| inner | |
| .opaque_type_storage | |
| .iter_opaque_types() | |
| .filter_map(|(key, hidden_ty)| { | |
| if let ty::Infer(ty::TyVar(hidden_vid)) = *hidden_ty.ty.kind() { | |
| let opaque_sub_vid = type_variables.sub_unification_table_root_var(hidden_vid); | |
| if opaque_sub_vid == ty_sub_vid { | |
| return Some(ty::OpaqueAliasTy::new_opaque_from_args( | |
| self.tcx, | |
| key.def_id.into(), | |
| key.args, | |
| )); | |
| } | |
| } | |
| None | |
| }) | |
| .collect() | |
| } | |
| #[inline(always)] | |
| pub fn can_define_opaque_ty(&self, id: impl Into<DefId>) -> bool { | |
| debug_assert!(!self.next_trait_solver()); | |
| match self.typing_mode_raw().assert_not_erased() { | |
| TypingMode::Typeck { defining_opaque_types_and_generators: defining_opaque_types } | |
| | TypingMode::PostTypeckUntilBorrowck { defining_opaque_types } => { | |
| id.into().as_local().is_some_and(|def_id| defining_opaque_types.contains(&def_id)) | |
| } | |
| // FIXME(#132279): This function is quite weird in post-analysis | |
| // and post-borrowck analysis mode. We may need to modify its uses | |
| // to support PostBorrowck in the old solver as well. | |
| TypingMode::Coherence | |
| | TypingMode::PostBorrowck { .. } | |
| | TypingMode::PostAnalysis | |
| | TypingMode::Codegen => false, | |
| } | |
| } | |
| pub fn push_hir_typeck_potentially_region_dependent_goal( | |
| &self, | |
| goal: PredicateObligation<'tcx>, | |
| ) { | |
| let mut inner = self.inner.borrow_mut(); | |
| inner.undo_log.push(UndoLog::PushHirTypeckPotentiallyRegionDependentGoal); | |
| inner.hir_typeck_potentially_region_dependent_goals.push(goal); | |
| } | |
| pub fn take_hir_typeck_potentially_region_dependent_goals( | |
| &self, | |
| ) -> Vec<PredicateObligation<'tcx>> { | |
| assert!(!self.in_snapshot(), "cannot take goals in a snapshot"); | |
| std::mem::take(&mut self.inner.borrow_mut().hir_typeck_potentially_region_dependent_goals) | |
| } | |
| pub fn ty_to_string(&self, t: Ty<'tcx>) -> String { | |
| self.resolve_vars_if_possible(t).to_string() | |
| } | |
| /// If `TyVar(vid)` resolves to a type, return that type. Else, return the | |
| /// universe index of `TyVar(vid)`. | |
| pub fn try_resolve_ty_var(&self, vid: TyVid) -> Result<Ty<'tcx>, ty::UniverseIndex> { | |
| use self::type_variable::TypeVariableValue; | |
| match self.inner.borrow_mut().type_variables().probe(vid) { | |
| TypeVariableValue::Known { value } => Ok(value), | |
| TypeVariableValue::Unknown { universe } => Err(universe), | |
| } | |
| } | |
| pub fn shallow_resolve(&self, ty: Ty<'tcx>) -> Ty<'tcx> { | |
| if let ty::Infer(v) = *ty.kind() { | |
| match v { | |
| ty::TyVar(v) => { | |
| // Not entirely obvious: if `typ` is a type variable, | |
| // it can be resolved to an int/float variable, which | |
| // can then be recursively resolved, hence the | |
| // recursion. Note though that we prevent type | |
| // variables from unifying to other type variables | |
| // directly (though they may be embedded | |
| // structurally), and we prevent cycles in any case, | |
| // so this recursion should always be of very limited | |
| // depth. | |
| // | |
| // Note: if these two lines are combined into one we get | |
| // dynamic borrow errors on `self.inner`. | |
| let known = self.inner.borrow_mut().type_variables().probe(v).known(); | |
| known.map_or(ty, |t| self.shallow_resolve(t)) | |
| } | |
| ty::IntVar(v) => { | |
| match self.inner.borrow_mut().int_unification_table().probe_value(v) { | |
| ty::IntVarValue::IntType(ty) => Ty::new_int(self.tcx, ty), | |
| ty::IntVarValue::UintType(ty) => Ty::new_uint(self.tcx, ty), | |
| ty::IntVarValue::Unknown => ty, | |
| } | |
| } | |
| ty::FloatVar(v) => { | |
| match self.inner.borrow_mut().float_unification_table().probe_value(v) { | |
| ty::FloatVarValue::Known(ty) => Ty::new_float(self.tcx, ty), | |
| ty::FloatVarValue::Unknown => ty, | |
| } | |
| } | |
| ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_) => ty, | |
| } | |
| } else { | |
| ty | |
| } | |
| } | |
| pub fn shallow_resolve_const(&self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> { | |
| match ct.kind() { | |
| ty::ConstKind::Infer(infer_ct) => match infer_ct { | |
| InferConst::Var(vid) => self | |
| .inner | |
| .borrow_mut() | |
| .const_unification_table() | |
| .probe_value(vid) | |
| .known() | |
| .unwrap_or(ct), | |
| InferConst::Fresh(_) => ct, | |
| }, | |
| ty::ConstKind::Param(_) | |
| | ty::ConstKind::Bound(_, _) | |
| | ty::ConstKind::Placeholder(_) | |
| | ty::ConstKind::Alias(_, _) | |
| | ty::ConstKind::Value(_) | |
| | ty::ConstKind::Error(_) | |
| | ty::ConstKind::Expr(_) => ct, | |
| } | |
| } | |
| pub fn shallow_resolve_term(&self, term: ty::Term<'tcx>) -> ty::Term<'tcx> { | |
| match term.kind() { | |
| ty::TermKind::Ty(ty) => self.shallow_resolve(ty).into(), | |
| ty::TermKind::Const(ct) => self.shallow_resolve_const(ct).into(), | |
| } | |
| } | |
| pub fn root_var(&self, var: ty::TyVid) -> ty::TyVid { | |
| self.inner.borrow_mut().type_variables().root_var(var) | |
| } | |
| pub fn sub_unify_ty_vids_raw(&self, a: ty::TyVid, b: ty::TyVid) { | |
| self.inner.borrow_mut().type_variables().sub_unify(a, b); | |
| } | |
| pub fn sub_unification_table_root_var(&self, var: ty::TyVid) -> ty::TyVid { | |
| self.inner.borrow_mut().type_variables().sub_unification_table_root_var(var) | |
| } | |
| pub fn root_float_var(&self, var: ty::FloatVid) -> ty::FloatVid { | |
| self.inner.borrow_mut().float_unification_table().find(var) | |
| } | |
| pub fn root_const_var(&self, var: ty::ConstVid) -> ty::ConstVid { | |
| self.inner.borrow_mut().const_unification_table().find(var).vid | |
| } | |
| /// Resolves an int var to a rigid int type, if it was constrained to one, | |
| /// or else the root int var in the unification table. | |
| pub fn opportunistic_resolve_int_var(&self, vid: ty::IntVid) -> Ty<'tcx> { | |
| let mut inner = self.inner.borrow_mut(); | |
| let value = inner.int_unification_table().probe_value(vid); | |
| match value { | |
| ty::IntVarValue::IntType(ty) => Ty::new_int(self.tcx, ty), | |
| ty::IntVarValue::UintType(ty) => Ty::new_uint(self.tcx, ty), | |
| ty::IntVarValue::Unknown => { | |
| Ty::new_int_var(self.tcx, inner.int_unification_table().find(vid)) | |
| } | |
| } | |
| } | |
| /// Resolves a float var to a rigid int type, if it was constrained to one, | |
| /// or else the root float var in the unification table. | |
| pub fn opportunistic_resolve_float_var(&self, vid: ty::FloatVid) -> Ty<'tcx> { | |
| let mut inner = self.inner.borrow_mut(); | |
| let value = inner.float_unification_table().probe_value(vid); | |
| match value { | |
| ty::FloatVarValue::Known(ty) => Ty::new_float(self.tcx, ty), | |
| ty::FloatVarValue::Unknown => { | |
| Ty::new_float_var(self.tcx, inner.float_unification_table().find(vid)) | |
| } | |
| } | |
| } | |
| /// Where possible, replaces type/const variables in | |
| /// `value` with their final value. Note that region variables | |
| /// are unaffected. If a type/const variable has not been unified, it | |
| /// is left as is. This is an idempotent operation that does | |
| /// not affect inference state in any way and so you can do it | |
| /// at will. | |
| pub fn resolve_vars_if_possible<T>(&self, value: T) -> T | |
| where | |
| T: TypeFoldable<TyCtxt<'tcx>>, | |
| { | |
| if let Err(guar) = value.error_reported() { | |
| self.set_tainted_by_errors(guar); | |
| } | |
| if !value.has_non_region_infer() { | |
| return value; | |
| } | |
| let mut r = resolve::OpportunisticVarResolver::new(self); | |
| value.fold_with(&mut r) | |
| } | |
| pub fn resolve_numeric_literals_with_default<T>(&self, value: T) -> T | |
| where | |
| T: TypeFoldable<TyCtxt<'tcx>>, | |
| { | |
| if !value.has_infer() { | |
| return value; // Avoid duplicated type-folding. | |
| } | |
| let mut r = InferenceLiteralEraser { tcx: self.tcx }; | |
| value.fold_with(&mut r) | |
| } | |
| pub fn try_resolve_const_var( | |
| &self, | |
| vid: ty::ConstVid, | |
| ) -> Result<ty::Const<'tcx>, ty::UniverseIndex> { | |
| match self.inner.borrow_mut().const_unification_table().probe_value(vid) { | |
| ConstVariableValue::Known { value } => Ok(value), | |
| ConstVariableValue::Unknown { origin: _, universe } => Err(universe), | |
| } | |
| } | |
| /// Attempts to resolve all type/region/const variables in | |
| /// `value`. Region inference must have been run already (e.g., | |
| /// by calling `resolve_regions_and_report_errors`). If some | |
| /// variable was never unified, an `Err` results. | |
| /// | |
| /// This method is idempotent, but it not typically not invoked | |
| /// except during the writeback phase. | |
| pub fn fully_resolve<T: TypeFoldable<TyCtxt<'tcx>>>(&self, value: T) -> FixupResult<T> { | |
| match resolve::fully_resolve(self, value) { | |
| Ok(value) => { | |
| if value.has_non_region_infer() { | |
| bug!("`{value:?}` is not fully resolved"); | |
| } | |
| if value.has_infer_regions() { | |
| let guar = self.dcx().delayed_bug(format!("`{value:?}` is not fully resolved")); | |
| Ok(fold_regions(self.tcx, value, |re, _| { | |
| if re.is_var() { ty::Region::new_error(self.tcx, guar) } else { re } | |
| })) | |
| } else { | |
| Ok(value) | |
| } | |
| } | |
| Err(e) => Err(e), | |
| } | |
| } | |
| // Instantiates the bound variables in a given binder with fresh inference | |
| // variables in the current universe. | |
| // | |
| // Use this method if you'd like to find some generic parameters of the binder's | |
| // variables (e.g. during a method call). If there isn't a [`BoundRegionConversionTime`] | |
| // that corresponds to your use case, consider whether or not you should | |
| // use [`InferCtxt::enter_forall`] instead. | |
| pub fn instantiate_binder_with_fresh_vars<T>( | |
| &self, | |
| span: Span, | |
| lbrct: BoundRegionConversionTime, | |
| value: ty::Binder<'tcx, T>, | |
| ) -> T | |
| where | |
| T: TypeFoldable<TyCtxt<'tcx>> + Copy, | |
| { | |
| if let Some(inner) = value.no_bound_vars() { | |
| return inner; | |
| } | |
| let bound_vars = value.bound_vars(); | |
| let mut args = Vec::with_capacity(bound_vars.len()); | |
| for bound_var_kind in bound_vars { | |
| let arg: ty::GenericArg<'_> = match bound_var_kind { | |
| ty::BoundVariableKind::Ty(_) => self.next_ty_var(span).into(), | |
| ty::BoundVariableKind::Region(br) => { | |
| self.next_region_var(RegionVariableOrigin::BoundRegion(span, br, lbrct)).into() | |
| } | |
| ty::BoundVariableKind::Const => self.next_const_var(span).into(), | |
| }; | |
| args.push(arg); | |
| } | |
| struct ToFreshVars<'tcx> { | |
| args: Vec<ty::GenericArg<'tcx>>, | |
| } | |
| impl<'tcx> BoundVarReplacerDelegate<'tcx> for ToFreshVars<'tcx> { | |
| fn replace_region(&mut self, br: ty::BoundRegion<'tcx>) -> ty::Region<'tcx> { | |
| self.args[br.var.index()].expect_region() | |
| } | |
| fn replace_ty(&mut self, bt: ty::BoundTy<'tcx>) -> Ty<'tcx> { | |
| self.args[bt.var.index()].expect_ty() | |
| } | |
| fn replace_const(&mut self, bc: ty::BoundConst<'tcx>) -> ty::Const<'tcx> { | |
| self.args[bc.var.index()].expect_const() | |
| } | |
| } | |
| let delegate = ToFreshVars { args }; | |
| self.tcx.replace_bound_vars_uncached(value, delegate) | |
| } | |
| /// See the [`region_constraints::RegionConstraintCollector::verify_generic_bound`] method. | |
| pub(crate) fn verify_generic_bound( | |
| &self, | |
| origin: SubregionOrigin<'tcx>, | |
| kind: GenericKind<'tcx>, | |
| a: ty::Region<'tcx>, | |
| bound: VerifyBound<'tcx>, | |
| ) { | |
| debug!("verify_generic_bound({:?}, {:?} <: {:?})", kind, a, bound); | |
| self.inner | |
| .borrow_mut() | |
| .unwrap_region_constraints() | |
| .verify_generic_bound(origin, kind, a, bound); | |
| } | |
| /// Obtains the latest type of the given closure; this may be a | |
| /// closure in the current function, in which case its | |
| /// `ClosureKind` may not yet be known. | |
| pub fn closure_kind(&self, closure_ty: Ty<'tcx>) -> Option<ty::ClosureKind> { | |
| let unresolved_kind_ty = match *closure_ty.kind() { | |
| ty::Closure(_, args) => args.as_closure().kind_ty(), | |
| ty::CoroutineClosure(_, args) => args.as_coroutine_closure().kind_ty(), | |
| _ => bug!("unexpected type {closure_ty}"), | |
| }; | |
| let closure_kind_ty = self.shallow_resolve(unresolved_kind_ty); | |
| closure_kind_ty.to_opt_closure_kind() | |
| } | |
| pub fn universe(&self) -> ty::UniverseIndex { | |
| self.universe.get() | |
| } | |
| /// Creates and return a fresh universe that extends all previous | |
| /// universes. Updates `self.universe` to that new universe. | |
| pub fn create_next_universe(&self) -> ty::UniverseIndex { | |
| let u = self.universe.get().next_universe(); | |
| debug!("create_next_universe {u:?}"); | |
| self.universe.set(u); | |
| u | |
| } | |
| /// Extract [`ty::TypingMode`] of this inference context to get a `TypingEnv` | |
| /// which contains the necessary information to use the trait system without | |
| /// using canonicalization or carrying this inference context around. | |
| pub fn typing_env(&self, param_env: ty::ParamEnv<'tcx>) -> ty::TypingEnv<'tcx> { | |
| let typing_mode = match self.typing_mode_raw() { | |
| // FIXME(#132279): This erases the `defining_opaque_types` as it isn't possible | |
| // to handle them without proper canonicalization. This means we may cause cycle | |
| // errors and fail to reveal opaques while inside of bodies. We should rename this | |
| // function and require explicit comments on all use-sites in the future. | |
| ty::TypingMode::Typeck { defining_opaque_types_and_generators: _ } | |
| | ty::TypingMode::PostTypeckUntilBorrowck { defining_opaque_types: _ } => { | |
| TypingMode::non_body_analysis() | |
| } | |
| mode @ (ty::TypingMode::Coherence | |
| | ty::TypingMode::PostBorrowck { .. } | |
| | ty::TypingMode::PostAnalysis | |
| | ty::TypingMode::Codegen) => mode, | |
| ty::TypingMode::ErasedNotCoherence(MayBeErased) => unreachable!(), | |
| }; | |
| ty::TypingEnv::new(param_env, typing_mode) | |
| } | |
| /// Similar to [`Self::canonicalize_query`], except that it returns | |
| /// a [`PseudoCanonicalInput`] and requires both the `value` and the | |
| /// `param_env` to not contain any inference variables or placeholders. | |
| pub fn pseudo_canonicalize_query<V>( | |
| &self, | |
| param_env: ty::ParamEnv<'tcx>, | |
| value: V, | |
| ) -> PseudoCanonicalInput<'tcx, V> | |
| where | |
| V: TypeVisitable<TyCtxt<'tcx>>, | |
| { | |
| debug_assert!(!value.has_infer()); | |
| debug_assert!(!value.has_placeholders()); | |
| debug_assert!(!param_env.has_infer()); | |
| debug_assert!(!param_env.has_placeholders()); | |
| self.typing_env(param_env).as_query_input(value) | |
| } | |
| /// The returned function is used in a fast path. If it returns `true` the variable is | |
| /// unchanged, `false` indicates that the status is unknown. | |
| #[inline] | |
| pub fn is_ty_infer_var_definitely_unchanged(&self) -> impl Fn(TyOrConstInferVar) -> bool { | |
| // This hoists the borrow/release out of the loop body. | |
| let inner = self.inner.try_borrow(); | |
| move |infer_var: TyOrConstInferVar| match (infer_var, &inner) { | |
| (TyOrConstInferVar::Ty(ty_var), Ok(inner)) => { | |
| use self::type_variable::TypeVariableValue; | |
| matches!( | |
| inner.try_type_variables_probe_ref(ty_var), | |
| Some(TypeVariableValue::Unknown { .. }) | |
| ) | |
| } | |
| _ => false, | |
| } | |
| } | |
| /// `ty_or_const_infer_var_changed` is equivalent to one of these two: | |
| /// * `shallow_resolve(ty) != ty` (where `ty.kind = ty::Infer(_)`) | |
| /// * `shallow_resolve(ct) != ct` (where `ct.kind = ty::ConstKind::Infer(_)`) | |
| /// | |
| /// However, `ty_or_const_infer_var_changed` is more efficient. It's always | |
| /// inlined, despite being large, because it has only two call sites that | |
| /// are extremely hot (both in `traits::fulfill`'s checking of `stalled_on` | |
| /// inference variables), and it handles both `Ty` and `ty::Const` without | |
| /// having to resort to storing full `GenericArg`s in `stalled_on`. | |
| #[inline(always)] | |
| pub fn ty_or_const_infer_var_changed(&self, infer_var: TyOrConstInferVar) -> bool { | |
| match infer_var { | |
| TyOrConstInferVar::Ty(v) => { | |
| use self::type_variable::TypeVariableValue; | |
| // If `inlined_probe` returns a `Known` value, it never equals | |
| // `ty::Infer(ty::TyVar(v))`. | |
| match self.inner.borrow_mut().type_variables().inlined_probe(v) { | |
| TypeVariableValue::Unknown { .. } => false, | |
| TypeVariableValue::Known { .. } => true, | |
| } | |
| } | |
| TyOrConstInferVar::TyInt(v) => { | |
| // If `inlined_probe_value` returns a value it's always a | |
| // `ty::Int(_)` or `ty::UInt(_)`, which never matches a | |
| // `ty::Infer(_)`. | |
| self.inner.borrow_mut().int_unification_table().inlined_probe_value(v).is_known() | |
| } | |
| TyOrConstInferVar::TyFloat(v) => { | |
| // If `probe_value` returns a value it's always a | |
| // `ty::Float(_)`, which never matches a `ty::Infer(_)`. | |
| // | |
| // Not `inlined_probe_value(v)` because this call site is colder. | |
| self.inner.borrow_mut().float_unification_table().probe_value(v).is_known() | |
| } | |
| TyOrConstInferVar::Const(v) => { | |
| // If `probe_value` returns a `Known` value, it never equals | |
| // `ty::ConstKind::Infer(ty::InferConst::Var(v))`. | |
| // | |
| // Not `inlined_probe_value(v)` because this call site is colder. | |
| match self.inner.borrow_mut().const_unification_table().probe_value(v) { | |
| ConstVariableValue::Unknown { .. } => false, | |
| ConstVariableValue::Known { .. } => true, | |
| } | |
| } | |
| } | |
| } | |
| /// Attach a callback to be invoked on each root obligation evaluated in the new trait solver. | |
| pub fn attach_obligation_inspector(&self, inspector: ObligationInspector<'tcx>) { | |
| debug_assert!( | |
| self.obligation_inspector.get().is_none(), | |
| "shouldn't override a set obligation inspector" | |
| ); | |
| self.obligation_inspector.set(Some(inspector)); | |
| } | |
| } | |
| /// Helper for [InferCtxt::ty_or_const_infer_var_changed] (see comment on that), currently | |
| /// used only for `traits::fulfill`'s list of `stalled_on` inference variables. | |
| #[derive(Copy, Clone, Debug)] | |
| pub enum TyOrConstInferVar { | |
| /// Equivalent to `ty::Infer(ty::TyVar(_))`. | |
| Ty(TyVid), | |
| /// Equivalent to `ty::Infer(ty::IntVar(_))`. | |
| TyInt(IntVid), | |
| /// Equivalent to `ty::Infer(ty::FloatVar(_))`. | |
| TyFloat(FloatVid), | |
| /// Equivalent to `ty::ConstKind::Infer(ty::InferConst::Var(_))`. | |
| Const(ConstVid), | |
| } | |
| impl<'tcx> TyOrConstInferVar { | |
| /// Tries to extract an inference variable from a type or a constant, returns `None` | |
| /// for types other than `ty::Infer(_)` (or `InferTy::Fresh*`) and | |
| /// for constants other than `ty::ConstKind::Infer(_)` (or `InferConst::Fresh`). | |
| pub fn maybe_from_generic_arg(arg: GenericArg<'tcx>) -> Option<Self> { | |
| match arg.kind() { | |
| GenericArgKind::Type(ty) => Self::maybe_from_ty(ty), | |
| GenericArgKind::Const(ct) => Self::maybe_from_const(ct), | |
| GenericArgKind::Lifetime(_) => None, | |
| } | |
| } | |
| /// Tries to extract an inference variable from a type or a constant, returns `None` | |
| /// for types other than `ty::Infer(_)` (or `InferTy::Fresh*`) and | |
| /// for constants other than `ty::ConstKind::Infer(_)` (or `InferConst::Fresh`). | |
| pub fn maybe_from_term(term: Term<'tcx>) -> Option<Self> { | |
| match term.kind() { | |
| TermKind::Ty(ty) => Self::maybe_from_ty(ty), | |
| TermKind::Const(ct) => Self::maybe_from_const(ct), | |
| } | |
| } | |
| /// Tries to extract an inference variable from a type, returns `None` | |
| /// for types other than `ty::Infer(_)` (or `InferTy::Fresh*`). | |
| fn maybe_from_ty(ty: Ty<'tcx>) -> Option<Self> { | |
| match *ty.kind() { | |
| ty::Infer(ty::TyVar(v)) => Some(TyOrConstInferVar::Ty(v)), | |
| ty::Infer(ty::IntVar(v)) => Some(TyOrConstInferVar::TyInt(v)), | |
| ty::Infer(ty::FloatVar(v)) => Some(TyOrConstInferVar::TyFloat(v)), | |
| _ => None, | |
| } | |
| } | |
| /// Tries to extract an inference variable from a constant, returns `None` | |
| /// for constants other than `ty::ConstKind::Infer(_)` (or `InferConst::Fresh`). | |
| fn maybe_from_const(ct: ty::Const<'tcx>) -> Option<Self> { | |
| match ct.kind() { | |
| ty::ConstKind::Infer(InferConst::Var(v)) => Some(TyOrConstInferVar::Const(v)), | |
| _ => None, | |
| } | |
| } | |
| } | |
| /// Replace `{integer}` with `i32` and `{float}` with `f64`. | |
| /// Used only for diagnostics. | |
| struct InferenceLiteralEraser<'tcx> { | |
| tcx: TyCtxt<'tcx>, | |
| } | |
| impl<'tcx> TypeFolder<TyCtxt<'tcx>> for InferenceLiteralEraser<'tcx> { | |
| fn cx(&self) -> TyCtxt<'tcx> { | |
| self.tcx | |
| } | |
| fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { | |
| match ty.kind() { | |
| ty::Infer(ty::IntVar(_) | ty::FreshIntTy(_)) => self.tcx.types.i32, | |
| ty::Infer(ty::FloatVar(_) | ty::FreshFloatTy(_)) => self.tcx.types.f64, | |
| _ => ty.super_fold_with(self), | |
| } | |
| } | |
| } | |
| impl<'tcx> TypeTrace<'tcx> { | |
| pub fn span(&self) -> Span { | |
| self.cause.span | |
| } | |
| pub fn types(cause: &ObligationCause<'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> TypeTrace<'tcx> { | |
| TypeTrace { | |
| cause: cause.clone(), | |
| values: ValuePairs::Terms(ExpectedFound::new(a.into(), b.into())), | |
| } | |
| } | |
| pub fn trait_refs( | |
| cause: &ObligationCause<'tcx>, | |
| a: ty::TraitRef<'tcx>, | |
| b: ty::TraitRef<'tcx>, | |
| ) -> TypeTrace<'tcx> { | |
| TypeTrace { cause: cause.clone(), values: ValuePairs::TraitRefs(ExpectedFound::new(a, b)) } | |
| } | |
| pub fn consts( | |
| cause: &ObligationCause<'tcx>, | |
| a: ty::Const<'tcx>, | |
| b: ty::Const<'tcx>, | |
| ) -> TypeTrace<'tcx> { | |
| TypeTrace { | |
| cause: cause.clone(), | |
| values: ValuePairs::Terms(ExpectedFound::new(a.into(), b.into())), | |
| } | |
| } | |
| } | |
| impl<'tcx> SubregionOrigin<'tcx> { | |
| pub fn span(&self) -> Span { | |
| match *self { | |
| SubregionOrigin::Subtype(ref a) => a.span(), | |
| SubregionOrigin::RelateObjectBound(a) => a, | |
| SubregionOrigin::RelateParamBound(a, ..) => a, | |
| SubregionOrigin::RelateRegionParamBound(a, _) => a, | |
| SubregionOrigin::Reborrow(a) => a, | |
| SubregionOrigin::ReferenceOutlivesReferent(_, a) => a, | |
| SubregionOrigin::CompareImplItemObligation { span, .. } => span, | |
| SubregionOrigin::AscribeUserTypeProvePredicate(span) => span, | |
| SubregionOrigin::CheckAssociatedTypeBounds { ref parent, .. } => parent.span(), | |
| SubregionOrigin::SolverRegionConstraint(a) => a, | |
| } | |
| } | |
| pub fn from_obligation_cause<F>(cause: &traits::ObligationCause<'tcx>, default: F) -> Self | |
| where | |
| F: FnOnce() -> Self, | |
| { | |
| match *cause.code() { | |
| traits::ObligationCauseCode::ReferenceOutlivesReferent(ref_type) => { | |
| SubregionOrigin::ReferenceOutlivesReferent(ref_type, cause.span) | |
| } | |
| traits::ObligationCauseCode::CompareImplItem { | |
| impl_item_def_id, | |
| trait_item_def_id, | |
| kind: _, | |
| } => SubregionOrigin::CompareImplItemObligation { | |
| span: cause.span, | |
| impl_item_def_id, | |
| trait_item_def_id, | |
| }, | |
| traits::ObligationCauseCode::CheckAssociatedTypeBounds { | |
| impl_item_def_id, | |
| trait_item_def_id, | |
| } => SubregionOrigin::CheckAssociatedTypeBounds { | |
| impl_item_def_id, | |
| trait_item_def_id, | |
| parent: Box::new(default()), | |
| }, | |
| traits::ObligationCauseCode::AscribeUserTypeProvePredicate(span) => { | |
| SubregionOrigin::AscribeUserTypeProvePredicate(span) | |
| } | |
| traits::ObligationCauseCode::ObjectTypeBound(ty, _reg) => { | |
| SubregionOrigin::RelateRegionParamBound(cause.span, Some(ty)) | |
| } | |
| _ => default(), | |
| } | |
| } | |
| } | |
| impl<'tcx> RegionVariableOrigin<'tcx> { | |
| pub fn span(&self) -> Span { | |
| match *self { | |
| RegionVariableOrigin::Misc(a) | |
| | RegionVariableOrigin::PatternRegion(a) | |
| | RegionVariableOrigin::BorrowRegion(a) | |
| | RegionVariableOrigin::Autoref(a) | |
| | RegionVariableOrigin::Coercion(a) | |
| | RegionVariableOrigin::RegionParameterDefinition(a, ..) | |
| | RegionVariableOrigin::BoundRegion(a, ..) | |
| | RegionVariableOrigin::UpvarRegion(_, a) => a, | |
| RegionVariableOrigin::Nll(..) => bug!("NLL variable used with `span`"), | |
| } | |
| } | |
| } | |
| impl<'tcx> InferCtxt<'tcx> { | |
| /// Given a [`hir::Block`], get the span of its last expression or | |
| /// statement, peeling off any inner blocks. | |
| pub fn find_block_span(&self, block: &'tcx hir::Block<'tcx>) -> Span { | |
| let block = block.innermost_block(); | |
| if let Some(expr) = &block.expr { | |
| expr.span | |
| } else if let Some(stmt) = block.stmts.last() { | |
| // possibly incorrect trailing `;` in the else arm | |
| stmt.span | |
| } else { | |
| // empty block; point at its entirety | |
| block.span | |
| } | |
| } | |
| /// Given a [`hir::HirId`] for a block (or an expr of a block), get the span | |
| /// of its last expression or statement, peeling off any inner blocks. | |
| pub fn find_block_span_from_hir_id(&self, hir_id: hir::HirId) -> Span { | |
| match self.tcx.hir_node(hir_id) { | |
| hir::Node::Block(blk) | |
| | hir::Node::Expr(&hir::Expr { kind: hir::ExprKind::Block(blk, _), .. }) => { | |
| self.find_block_span(blk) | |
| } | |
| hir::Node::Expr(e) => e.span, | |
| _ => DUMMY_SP, | |
| } | |
| } | |
| } | |
| type SolverRegionConstraint<'tcx> = | |
| rustc_type_ir::region_constraint::RegionConstraint<TyCtxt<'tcx>>; | |
| #[derive(Clone, Debug)] | |
| struct SolverRegionConstraintStorage<'tcx>(SolverRegionConstraint<'tcx>); | |
| impl<'tcx> SolverRegionConstraintStorage<'tcx> { | |
| fn new() -> Self { | |
| SolverRegionConstraintStorage(SolverRegionConstraint::And(Box::new([]))) | |
| } | |
| fn get_constraint(&self) -> SolverRegionConstraint<'tcx> { | |
| self.0.clone() | |
| } | |
| fn pop(&mut self) -> Option<SolverRegionConstraint<'tcx>> { | |
| match &mut self.0 { | |
| SolverRegionConstraint::And(and) => { | |
| let mut and = core::mem::take(and).into_iter().collect::<Vec<_>>(); | |
| let popped = and.pop()?; | |
| self.0 = SolverRegionConstraint::And(and.into_boxed_slice()); | |
| Some(popped) | |
| } | |
| _ => unreachable!(), | |
| } | |
| } | |
| #[instrument(level = "debug")] | |
| fn push(&mut self, constraint: SolverRegionConstraint<'tcx>) { | |
| match &mut self.0 { | |
| SolverRegionConstraint::And(and) => { | |
| let and = core::mem::take(and) | |
| .into_iter() | |
| .chain([constraint]) | |
| .collect::<Vec<_>>() | |
| .into_boxed_slice(); | |
| self.0 = SolverRegionConstraint::And(and); | |
| } | |
| _ => unreachable!(), | |
| } | |
| } | |
| #[instrument(level = "debug", skip(self))] | |
| fn overwrite_solver_region_constraint(&mut self, constraint: SolverRegionConstraint<'tcx>) { | |
| if !constraint.is_and() { | |
| self.0 = SolverRegionConstraint::And(vec![constraint].into_boxed_slice()) | |
| } else { | |
| self.0 = constraint; | |
| } | |
| } | |
| } |