| //! Trait Resolution. See the [rustc guide] for more information on how this works. |
| //! |
| //! [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/resolution.html |
| |
| #[allow(dead_code)] |
| pub mod auto_trait; |
| mod chalk_fulfill; |
| mod coherence; |
| pub mod error_reporting; |
| mod engine; |
| mod fulfill; |
| mod project; |
| mod object_safety; |
| mod on_unimplemented; |
| mod select; |
| mod specialize; |
| mod structural_impls; |
| pub mod codegen; |
| mod util; |
| pub mod query; |
| |
| use chalk_engine; |
| use crate::hir; |
| use crate::hir::def_id::DefId; |
| use crate::infer::{InferCtxt, SuppressRegionErrors}; |
| use crate::infer::outlives::env::OutlivesEnvironment; |
| use crate::middle::region; |
| use crate::mir::interpret::ErrorHandled; |
| use rustc_macros::HashStable; |
| use syntax::ast; |
| use syntax_pos::{Span, DUMMY_SP}; |
| use crate::ty::subst::{InternalSubsts, SubstsRef}; |
| use crate::ty::{self, AdtKind, List, Ty, TyCtxt, GenericParamDefKind, ToPredicate}; |
| use crate::ty::error::{ExpectedFound, TypeError}; |
| use crate::ty::fold::{TypeFolder, TypeFoldable, TypeVisitor}; |
| use crate::util::common::ErrorReported; |
| |
| use std::fmt::Debug; |
| use std::rc::Rc; |
| |
| pub use self::SelectionError::*; |
| pub use self::FulfillmentErrorCode::*; |
| pub use self::Vtable::*; |
| pub use self::ObligationCauseCode::*; |
| |
| pub use self::coherence::{add_placeholder_note, orphan_check, overlapping_impls}; |
| pub use self::coherence::{OrphanCheckErr, OverlapResult}; |
| pub use self::fulfill::{FulfillmentContext, PendingPredicateObligation}; |
| pub use self::project::MismatchedProjectionTypes; |
| pub use self::project::{normalize, normalize_projection_type, poly_project_and_unify_type}; |
| pub use self::project::{ProjectionCache, ProjectionCacheSnapshot, Reveal, Normalized}; |
| pub use self::object_safety::ObjectSafetyViolation; |
| pub use self::object_safety::MethodViolationCode; |
| pub use self::on_unimplemented::{OnUnimplementedDirective, OnUnimplementedNote}; |
| pub use self::select::{EvaluationCache, SelectionContext, SelectionCache}; |
| pub use self::select::{EvaluationResult, IntercrateAmbiguityCause, OverflowError}; |
| pub use self::specialize::{OverlapError, specialization_graph, translate_substs}; |
| pub use self::specialize::find_associated_item; |
| pub use self::specialize::specialization_graph::FutureCompatOverlapError; |
| pub use self::specialize::specialization_graph::FutureCompatOverlapErrorKind; |
| pub use self::engine::{TraitEngine, TraitEngineExt}; |
| pub use self::util::{elaborate_predicates, elaborate_trait_ref, elaborate_trait_refs}; |
| pub use self::util::{ |
| supertraits, supertrait_def_ids, transitive_bounds, Supertraits, SupertraitDefIds, |
| }; |
| pub use self::util::{expand_trait_aliases, TraitAliasExpander}; |
| |
| pub use self::chalk_fulfill::{ |
| CanonicalGoal as ChalkCanonicalGoal, |
| FulfillmentContext as ChalkFulfillmentContext |
| }; |
| |
| pub use self::ObligationCauseCode::*; |
| pub use self::FulfillmentErrorCode::*; |
| pub use self::SelectionError::*; |
| pub use self::Vtable::*; |
| |
| /// Whether to enable bug compatibility with issue #43355. |
| #[derive(Copy, Clone, PartialEq, Eq, Debug)] |
| pub enum IntercrateMode { |
| Issue43355, |
| Fixed |
| } |
| |
| /// The mode that trait queries run in. |
| #[derive(Copy, Clone, PartialEq, Eq, Debug)] |
| pub enum TraitQueryMode { |
| // Standard/un-canonicalized queries get accurate |
| // spans etc. passed in and hence can do reasonable |
| // error reporting on their own. |
| Standard, |
| // Canonicalized queries get dummy spans and hence |
| // must generally propagate errors to |
| // pre-canonicalization callsites. |
| Canonical, |
| } |
| |
| /// An `Obligation` represents some trait reference (e.g., `int: Eq`) for |
| /// which the vtable must be found. The process of finding a vtable is |
| /// called "resolving" the `Obligation`. This process consists of |
| /// either identifying an `impl` (e.g., `impl Eq for int`) that |
| /// provides the required vtable, or else finding a bound that is in |
| /// scope. The eventual result is usually a `Selection` (defined below). |
| #[derive(Clone, PartialEq, Eq, Hash)] |
| pub struct Obligation<'tcx, T> { |
| /// The reason we have to prove this thing. |
| pub cause: ObligationCause<'tcx>, |
| |
| /// The environment in which we should prove this thing. |
| pub param_env: ty::ParamEnv<'tcx>, |
| |
| /// The thing we are trying to prove. |
| pub predicate: T, |
| |
| /// If we started proving this as a result of trying to prove |
| /// something else, track the total depth to ensure termination. |
| /// If this goes over a certain threshold, we abort compilation -- |
| /// in such cases, we can not say whether or not the predicate |
| /// holds for certain. Stupid halting problem; such a drag. |
| pub recursion_depth: usize, |
| } |
| |
| pub type PredicateObligation<'tcx> = Obligation<'tcx, ty::Predicate<'tcx>>; |
| pub type TraitObligation<'tcx> = Obligation<'tcx, ty::PolyTraitPredicate<'tcx>>; |
| |
| /// The reason why we incurred this obligation; used for error reporting. |
| #[derive(Clone, Debug, PartialEq, Eq, Hash)] |
| pub struct ObligationCause<'tcx> { |
| pub span: Span, |
| |
| /// The ID of the fn body that triggered this obligation. This is |
| /// used for region obligations to determine the precise |
| /// environment in which the region obligation should be evaluated |
| /// (in particular, closures can add new assumptions). See the |
| /// field `region_obligations` of the `FulfillmentContext` for more |
| /// information. |
| pub body_id: hir::HirId, |
| |
| pub code: ObligationCauseCode<'tcx> |
| } |
| |
| impl<'tcx> ObligationCause<'tcx> { |
| pub fn span(&self, tcx: TyCtxt<'tcx>) -> Span { |
| match self.code { |
| ObligationCauseCode::CompareImplMethodObligation { .. } | |
| ObligationCauseCode::MainFunctionType | |
| ObligationCauseCode::StartFunctionType => { |
| tcx.sess.source_map().def_span(self.span) |
| } |
| ObligationCauseCode::MatchExpressionArm { arm_span, .. } => arm_span, |
| _ => self.span, |
| } |
| } |
| } |
| |
| #[derive(Clone, Debug, PartialEq, Eq, Hash)] |
| pub enum ObligationCauseCode<'tcx> { |
| /// Not well classified or should be obvious from the span. |
| MiscObligation, |
| |
| /// A slice or array is WF only if `T: Sized`. |
| SliceOrArrayElem, |
| |
| /// A tuple is WF only if its middle elements are `Sized`. |
| TupleElem, |
| |
| /// This is the trait reference from the given projection. |
| ProjectionWf(ty::ProjectionTy<'tcx>), |
| |
| /// In an impl of trait `X` for type `Y`, type `Y` must |
| /// also implement all supertraits of `X`. |
| ItemObligation(DefId), |
| |
| /// A type like `&'a T` is WF only if `T: 'a`. |
| ReferenceOutlivesReferent(Ty<'tcx>), |
| |
| /// A type like `Box<Foo<'a> + 'b>` is WF only if `'b: 'a`. |
| ObjectTypeBound(Ty<'tcx>, ty::Region<'tcx>), |
| |
| /// Obligation incurred due to an object cast. |
| ObjectCastObligation(/* Object type */ Ty<'tcx>), |
| |
| // Various cases where expressions must be sized/copy/etc: |
| /// L = X implies that L is Sized |
| AssignmentLhsSized, |
| /// (x1, .., xn) must be Sized |
| TupleInitializerSized, |
| /// S { ... } must be Sized |
| StructInitializerSized, |
| /// Type of each variable must be Sized |
| VariableType(hir::HirId), |
| /// Argument type must be Sized |
| SizedArgumentType, |
| /// Return type must be Sized |
| SizedReturnType, |
| /// Yield type must be Sized |
| SizedYieldType, |
| /// [T,..n] --> T must be Copy |
| RepeatVec, |
| |
| /// Types of fields (other than the last, except for packed structs) in a struct must be sized. |
| FieldSized { adt_kind: AdtKind, last: bool }, |
| |
| /// Constant expressions must be sized. |
| ConstSized, |
| |
| /// static items must have `Sync` type |
| SharedStatic, |
| |
| BuiltinDerivedObligation(DerivedObligationCause<'tcx>), |
| |
| ImplDerivedObligation(DerivedObligationCause<'tcx>), |
| |
| /// error derived when matching traits/impls; see ObligationCause for more details |
| CompareImplMethodObligation { |
| item_name: ast::Name, |
| impl_item_def_id: DefId, |
| trait_item_def_id: DefId, |
| }, |
| |
| /// Checking that this expression can be assigned where it needs to be |
| // FIXME(eddyb) #11161 is the original Expr required? |
| ExprAssignable, |
| |
| /// Computing common supertype in the arms of a match expression |
| MatchExpressionArm { |
| arm_span: Span, |
| source: hir::MatchSource, |
| prior_arms: Vec<Span>, |
| last_ty: Ty<'tcx>, |
| discrim_hir_id: hir::HirId, |
| }, |
| |
| /// Computing common supertype in the pattern guard for the arms of a match expression |
| MatchExpressionArmPattern { span: Span, ty: Ty<'tcx> }, |
| |
| /// Computing common supertype in an if expression |
| IfExpression { |
| then: Span, |
| outer: Option<Span>, |
| semicolon: Option<Span>, |
| }, |
| |
| /// Computing common supertype of an if expression with no else counter-part |
| IfExpressionWithNoElse, |
| |
| /// `main` has wrong type |
| MainFunctionType, |
| |
| /// `start` has wrong type |
| StartFunctionType, |
| |
| /// intrinsic has wrong type |
| IntrinsicType, |
| |
| /// method receiver |
| MethodReceiver, |
| |
| /// `return` with no expression |
| ReturnNoExpression, |
| |
| /// `return` with an expression |
| ReturnType(hir::HirId), |
| |
| /// Block implicit return |
| BlockTailExpression(hir::HirId), |
| |
| /// #[feature(trivial_bounds)] is not enabled |
| TrivialBound, |
| } |
| |
| #[derive(Clone, Debug, PartialEq, Eq, Hash)] |
| pub struct DerivedObligationCause<'tcx> { |
| /// The trait reference of the parent obligation that led to the |
| /// current obligation. Note that only trait obligations lead to |
| /// derived obligations, so we just store the trait reference here |
| /// directly. |
| parent_trait_ref: ty::PolyTraitRef<'tcx>, |
| |
| /// The parent trait had this cause. |
| parent_code: Rc<ObligationCauseCode<'tcx>> |
| } |
| |
| pub type Obligations<'tcx, O> = Vec<Obligation<'tcx, O>>; |
| pub type PredicateObligations<'tcx> = Vec<PredicateObligation<'tcx>>; |
| pub type TraitObligations<'tcx> = Vec<TraitObligation<'tcx>>; |
| |
| /// The following types: |
| /// * `WhereClause`, |
| /// * `WellFormed`, |
| /// * `FromEnv`, |
| /// * `DomainGoal`, |
| /// * `Goal`, |
| /// * `Clause`, |
| /// * `Environment`, |
| /// * `InEnvironment`, |
| /// are used for representing the trait system in the form of |
| /// logic programming clauses. They are part of the interface |
| /// for the chalk SLG solver. |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum WhereClause<'tcx> { |
| Implemented(ty::TraitPredicate<'tcx>), |
| ProjectionEq(ty::ProjectionPredicate<'tcx>), |
| RegionOutlives(ty::RegionOutlivesPredicate<'tcx>), |
| TypeOutlives(ty::TypeOutlivesPredicate<'tcx>), |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum WellFormed<'tcx> { |
| Trait(ty::TraitPredicate<'tcx>), |
| Ty(Ty<'tcx>), |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum FromEnv<'tcx> { |
| Trait(ty::TraitPredicate<'tcx>), |
| Ty(Ty<'tcx>), |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum DomainGoal<'tcx> { |
| Holds(WhereClause<'tcx>), |
| WellFormed(WellFormed<'tcx>), |
| FromEnv(FromEnv<'tcx>), |
| Normalize(ty::ProjectionPredicate<'tcx>), |
| } |
| |
| pub type PolyDomainGoal<'tcx> = ty::Binder<DomainGoal<'tcx>>; |
| |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum QuantifierKind { |
| Universal, |
| Existential, |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum GoalKind<'tcx> { |
| Implies(Clauses<'tcx>, Goal<'tcx>), |
| And(Goal<'tcx>, Goal<'tcx>), |
| Not(Goal<'tcx>), |
| DomainGoal(DomainGoal<'tcx>), |
| Quantified(QuantifierKind, ty::Binder<Goal<'tcx>>), |
| Subtype(Ty<'tcx>, Ty<'tcx>), |
| CannotProve, |
| } |
| |
| pub type Goal<'tcx> = &'tcx GoalKind<'tcx>; |
| |
| pub type Goals<'tcx> = &'tcx List<Goal<'tcx>>; |
| |
| impl<'tcx> DomainGoal<'tcx> { |
| pub fn into_goal(self) -> GoalKind<'tcx> { |
| GoalKind::DomainGoal(self) |
| } |
| |
| pub fn into_program_clause(self) -> ProgramClause<'tcx> { |
| ProgramClause { |
| goal: self, |
| hypotheses: ty::List::empty(), |
| category: ProgramClauseCategory::Other, |
| } |
| } |
| } |
| |
| impl<'tcx> GoalKind<'tcx> { |
| pub fn from_poly_domain_goal( |
| domain_goal: PolyDomainGoal<'tcx>, |
| tcx: TyCtxt<'tcx>, |
| ) -> GoalKind<'tcx> { |
| match domain_goal.no_bound_vars() { |
| Some(p) => p.into_goal(), |
| None => GoalKind::Quantified( |
| QuantifierKind::Universal, |
| domain_goal.map_bound(|p| tcx.mk_goal(p.into_goal())) |
| ), |
| } |
| } |
| } |
| |
| /// This matches the definition from Page 7 of "A Proof Procedure for the Logic of Hereditary |
| /// Harrop Formulas". |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum Clause<'tcx> { |
| Implies(ProgramClause<'tcx>), |
| ForAll(ty::Binder<ProgramClause<'tcx>>), |
| } |
| |
| impl Clause<'tcx> { |
| pub fn category(self) -> ProgramClauseCategory { |
| match self { |
| Clause::Implies(clause) => clause.category, |
| Clause::ForAll(clause) => clause.skip_binder().category, |
| } |
| } |
| } |
| |
| /// Multiple clauses. |
| pub type Clauses<'tcx> = &'tcx List<Clause<'tcx>>; |
| |
| /// A "program clause" has the form `D :- G1, ..., Gn`. It is saying |
| /// that the domain goal `D` is true if `G1...Gn` are provable. This |
| /// is equivalent to the implication `G1..Gn => D`; we usually write |
| /// it with the reverse implication operator `:-` to emphasize the way |
| /// that programs are actually solved (via backchaining, which starts |
| /// with the goal to solve and proceeds from there). |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub struct ProgramClause<'tcx> { |
| /// This goal will be considered true ... |
| pub goal: DomainGoal<'tcx>, |
| |
| /// ... if we can prove these hypotheses (there may be no hypotheses at all): |
| pub hypotheses: Goals<'tcx>, |
| |
| /// Useful for filtering clauses. |
| pub category: ProgramClauseCategory, |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub enum ProgramClauseCategory { |
| ImpliedBound, |
| WellFormed, |
| Other, |
| } |
| |
| /// A set of clauses that we assume to be true. |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub struct Environment<'tcx> { |
| pub clauses: Clauses<'tcx>, |
| } |
| |
| impl Environment<'tcx> { |
| pub fn with<G>(self, goal: G) -> InEnvironment<'tcx, G> { |
| InEnvironment { |
| environment: self, |
| goal, |
| } |
| } |
| } |
| |
| /// Something (usually a goal), along with an environment. |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable)] |
| pub struct InEnvironment<'tcx, G> { |
| pub environment: Environment<'tcx>, |
| pub goal: G, |
| } |
| |
| pub type Selection<'tcx> = Vtable<'tcx, PredicateObligation<'tcx>>; |
| |
| #[derive(Clone,Debug)] |
| pub enum SelectionError<'tcx> { |
| Unimplemented, |
| OutputTypeParameterMismatch(ty::PolyTraitRef<'tcx>, |
| ty::PolyTraitRef<'tcx>, |
| ty::error::TypeError<'tcx>), |
| TraitNotObjectSafe(DefId), |
| ConstEvalFailure(ErrorHandled), |
| Overflow, |
| } |
| |
| EnumTypeFoldableImpl! { |
| impl<'tcx> TypeFoldable<'tcx> for SelectionError<'tcx> { |
| (SelectionError::Unimplemented), |
| (SelectionError::OutputTypeParameterMismatch)(a, b, c), |
| (SelectionError::TraitNotObjectSafe)(a), |
| (SelectionError::ConstEvalFailure)(a), |
| (SelectionError::Overflow), |
| } |
| } |
| |
| pub struct FulfillmentError<'tcx> { |
| pub obligation: PredicateObligation<'tcx>, |
| pub code: FulfillmentErrorCode<'tcx> |
| } |
| |
| #[derive(Clone)] |
| pub enum FulfillmentErrorCode<'tcx> { |
| CodeSelectionError(SelectionError<'tcx>), |
| CodeProjectionError(MismatchedProjectionTypes<'tcx>), |
| CodeSubtypeError(ExpectedFound<Ty<'tcx>>, |
| TypeError<'tcx>), // always comes from a SubtypePredicate |
| CodeAmbiguity, |
| } |
| |
| /// When performing resolution, it is typically the case that there |
| /// can be one of three outcomes: |
| /// |
| /// - `Ok(Some(r))`: success occurred with result `r` |
| /// - `Ok(None)`: could not definitely determine anything, usually due |
| /// to inconclusive type inference. |
| /// - `Err(e)`: error `e` occurred |
| pub type SelectionResult<'tcx, T> = Result<Option<T>, SelectionError<'tcx>>; |
| |
| /// Given the successful resolution of an obligation, the `Vtable` |
| /// indicates where the vtable comes from. Note that while we call this |
| /// a "vtable", it does not necessarily indicate dynamic dispatch at |
| /// runtime. `Vtable` instances just tell the compiler where to find |
| /// methods, but in generic code those methods are typically statically |
| /// dispatched -- only when an object is constructed is a `Vtable` |
| /// instance reified into an actual vtable. |
| /// |
| /// For example, the vtable may be tied to a specific impl (case A), |
| /// or it may be relative to some bound that is in scope (case B). |
| /// |
| /// ``` |
| /// impl<T:Clone> Clone<T> for Option<T> { ... } // Impl_1 |
| /// impl<T:Clone> Clone<T> for Box<T> { ... } // Impl_2 |
| /// impl Clone for int { ... } // Impl_3 |
| /// |
| /// fn foo<T:Clone>(concrete: Option<Box<int>>, |
| /// param: T, |
| /// mixed: Option<T>) { |
| /// |
| /// // Case A: Vtable points at a specific impl. Only possible when |
| /// // type is concretely known. If the impl itself has bounded |
| /// // type parameters, Vtable will carry resolutions for those as well: |
| /// concrete.clone(); // Vtable(Impl_1, [Vtable(Impl_2, [Vtable(Impl_3)])]) |
| /// |
| /// // Case B: Vtable must be provided by caller. This applies when |
| /// // type is a type parameter. |
| /// param.clone(); // VtableParam |
| /// |
| /// // Case C: A mix of cases A and B. |
| /// mixed.clone(); // Vtable(Impl_1, [VtableParam]) |
| /// } |
| /// ``` |
| /// |
| /// ### The type parameter `N` |
| /// |
| /// See explanation on `VtableImplData`. |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub enum Vtable<'tcx, N> { |
| /// Vtable identifying a particular impl. |
| VtableImpl(VtableImplData<'tcx, N>), |
| |
| /// Vtable for auto trait implementations. |
| /// This carries the information and nested obligations with regards |
| /// to an auto implementation for a trait `Trait`. The nested obligations |
| /// ensure the trait implementation holds for all the constituent types. |
| VtableAutoImpl(VtableAutoImplData<N>), |
| |
| /// Successful resolution to an obligation provided by the caller |
| /// for some type parameter. The `Vec<N>` represents the |
| /// obligations incurred from normalizing the where-clause (if |
| /// any). |
| VtableParam(Vec<N>), |
| |
| /// Virtual calls through an object. |
| VtableObject(VtableObjectData<'tcx, N>), |
| |
| /// Successful resolution for a builtin trait. |
| VtableBuiltin(VtableBuiltinData<N>), |
| |
| /// Vtable automatically generated for a closure. The `DefId` is the ID |
| /// of the closure expression. This is a `VtableImpl` in spirit, but the |
| /// impl is generated by the compiler and does not appear in the source. |
| VtableClosure(VtableClosureData<'tcx, N>), |
| |
| /// Same as above, but for a function pointer type with the given signature. |
| VtableFnPointer(VtableFnPointerData<'tcx, N>), |
| |
| /// Vtable automatically generated for a generator. |
| VtableGenerator(VtableGeneratorData<'tcx, N>), |
| |
| /// Vtable for a trait alias. |
| VtableTraitAlias(VtableTraitAliasData<'tcx, N>), |
| } |
| |
| /// Identifies a particular impl in the source, along with a set of |
| /// substitutions from the impl's type/lifetime parameters. The |
| /// `nested` vector corresponds to the nested obligations attached to |
| /// the impl's type parameters. |
| /// |
| /// The type parameter `N` indicates the type used for "nested |
| /// obligations" that are required by the impl. During type check, this |
| /// is `Obligation`, as one might expect. During codegen, however, this |
| /// is `()`, because codegen only requires a shallow resolution of an |
| /// impl, and nested obligations are satisfied later. |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableImplData<'tcx, N> { |
| pub impl_def_id: DefId, |
| pub substs: SubstsRef<'tcx>, |
| pub nested: Vec<N> |
| } |
| |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableGeneratorData<'tcx, N> { |
| pub generator_def_id: DefId, |
| pub substs: ty::GeneratorSubsts<'tcx>, |
| /// Nested obligations. This can be non-empty if the generator |
| /// signature contains associated types. |
| pub nested: Vec<N> |
| } |
| |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableClosureData<'tcx, N> { |
| pub closure_def_id: DefId, |
| pub substs: ty::ClosureSubsts<'tcx>, |
| /// Nested obligations. This can be non-empty if the closure |
| /// signature contains associated types. |
| pub nested: Vec<N> |
| } |
| |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableAutoImplData<N> { |
| pub trait_def_id: DefId, |
| pub nested: Vec<N> |
| } |
| |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableBuiltinData<N> { |
| pub nested: Vec<N> |
| } |
| |
| /// A vtable for some object-safe trait `Foo` automatically derived |
| /// for the object type `Foo`. |
| #[derive(PartialEq, Eq, Clone, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableObjectData<'tcx, N> { |
| /// `Foo` upcast to the obligation trait. This will be some supertrait of `Foo`. |
| pub upcast_trait_ref: ty::PolyTraitRef<'tcx>, |
| |
| /// The vtable is formed by concatenating together the method lists of |
| /// the base object trait and all supertraits; this is the start of |
| /// `upcast_trait_ref`'s methods in that vtable. |
| pub vtable_base: usize, |
| |
| pub nested: Vec<N>, |
| } |
| |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableFnPointerData<'tcx, N> { |
| pub fn_ty: Ty<'tcx>, |
| pub nested: Vec<N> |
| } |
| |
| #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)] |
| pub struct VtableTraitAliasData<'tcx, N> { |
| pub alias_def_id: DefId, |
| pub substs: SubstsRef<'tcx>, |
| pub nested: Vec<N>, |
| } |
| |
| /// Creates predicate obligations from the generic bounds. |
| pub fn predicates_for_generics<'tcx>(cause: ObligationCause<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| generic_bounds: &ty::InstantiatedPredicates<'tcx>) |
| -> PredicateObligations<'tcx> |
| { |
| util::predicates_for_generics(cause, 0, param_env, generic_bounds) |
| } |
| |
| /// Determines whether the type `ty` is known to meet `bound` and |
| /// returns true if so. Returns false if `ty` either does not meet |
| /// `bound` or is not known to meet bound (note that this is |
| /// conservative towards *no impl*, which is the opposite of the |
| /// `evaluate` methods). |
| pub fn type_known_to_meet_bound_modulo_regions<'a, 'tcx>( |
| infcx: &InferCtxt<'a, 'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| ty: Ty<'tcx>, |
| def_id: DefId, |
| span: Span, |
| ) -> bool { |
| debug!("type_known_to_meet_bound_modulo_regions(ty={:?}, bound={:?})", |
| ty, |
| infcx.tcx.def_path_str(def_id)); |
| |
| let trait_ref = ty::TraitRef { |
| def_id, |
| substs: infcx.tcx.mk_substs_trait(ty, &[]), |
| }; |
| let obligation = Obligation { |
| param_env, |
| cause: ObligationCause::misc(span, hir::DUMMY_HIR_ID), |
| recursion_depth: 0, |
| predicate: trait_ref.to_predicate(), |
| }; |
| |
| let result = infcx.predicate_must_hold_modulo_regions(&obligation); |
| debug!("type_known_to_meet_ty={:?} bound={} => {:?}", |
| ty, infcx.tcx.def_path_str(def_id), result); |
| |
| if result && (ty.has_infer_types() || ty.has_closure_types()) { |
| // Because of inference "guessing", selection can sometimes claim |
| // to succeed while the success requires a guess. To ensure |
| // this function's result remains infallible, we must confirm |
| // that guess. While imperfect, I believe this is sound. |
| |
| // The handling of regions in this area of the code is terrible, |
| // see issue #29149. We should be able to improve on this with |
| // NLL. |
| let mut fulfill_cx = FulfillmentContext::new_ignoring_regions(); |
| |
| // We can use a dummy node-id here because we won't pay any mind |
| // to region obligations that arise (there shouldn't really be any |
| // anyhow). |
| let cause = ObligationCause::misc(span, hir::DUMMY_HIR_ID); |
| |
| fulfill_cx.register_bound(infcx, param_env, ty, def_id, cause); |
| |
| // Note: we only assume something is `Copy` if we can |
| // *definitively* show that it implements `Copy`. Otherwise, |
| // assume it is move; linear is always ok. |
| match fulfill_cx.select_all_or_error(infcx) { |
| Ok(()) => { |
| debug!("type_known_to_meet_bound_modulo_regions: ty={:?} bound={} success", |
| ty, |
| infcx.tcx.def_path_str(def_id)); |
| true |
| } |
| Err(e) => { |
| debug!("type_known_to_meet_bound_modulo_regions: ty={:?} bound={} errors={:?}", |
| ty, |
| infcx.tcx.def_path_str(def_id), |
| e); |
| false |
| } |
| } |
| } else { |
| result |
| } |
| } |
| |
| fn do_normalize_predicates<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| region_context: DefId, |
| cause: ObligationCause<'tcx>, |
| elaborated_env: ty::ParamEnv<'tcx>, |
| predicates: Vec<ty::Predicate<'tcx>>, |
| ) -> Result<Vec<ty::Predicate<'tcx>>, ErrorReported> { |
| debug!( |
| "do_normalize_predicates(predicates={:?}, region_context={:?}, cause={:?})", |
| predicates, |
| region_context, |
| cause, |
| ); |
| let span = cause.span; |
| tcx.infer_ctxt().enter(|infcx| { |
| // FIXME. We should really... do something with these region |
| // obligations. But this call just continues the older |
| // behavior (i.e., doesn't cause any new bugs), and it would |
| // take some further refactoring to actually solve them. In |
| // particular, we would have to handle implied bounds |
| // properly, and that code is currently largely confined to |
| // regionck (though I made some efforts to extract it |
| // out). -nmatsakis |
| // |
| // @arielby: In any case, these obligations are checked |
| // by wfcheck anyway, so I'm not sure we have to check |
| // them here too, and we will remove this function when |
| // we move over to lazy normalization *anyway*. |
| let fulfill_cx = FulfillmentContext::new_ignoring_regions(); |
| let predicates = match fully_normalize( |
| &infcx, |
| fulfill_cx, |
| cause, |
| elaborated_env, |
| &predicates, |
| ) { |
| Ok(predicates) => predicates, |
| Err(errors) => { |
| infcx.report_fulfillment_errors(&errors, None, false); |
| return Err(ErrorReported) |
| } |
| }; |
| |
| debug!("do_normalize_predictes: normalized predicates = {:?}", predicates); |
| |
| let region_scope_tree = region::ScopeTree::default(); |
| |
| // We can use the `elaborated_env` here; the region code only |
| // cares about declarations like `'a: 'b`. |
| let outlives_env = OutlivesEnvironment::new(elaborated_env); |
| |
| infcx.resolve_regions_and_report_errors( |
| region_context, |
| ®ion_scope_tree, |
| &outlives_env, |
| SuppressRegionErrors::default(), |
| ); |
| |
| let predicates = match infcx.fully_resolve(&predicates) { |
| Ok(predicates) => predicates, |
| Err(fixup_err) => { |
| // If we encounter a fixup error, it means that some type |
| // variable wound up unconstrained. I actually don't know |
| // if this can happen, and I certainly don't expect it to |
| // happen often, but if it did happen it probably |
| // represents a legitimate failure due to some kind of |
| // unconstrained variable, and it seems better not to ICE, |
| // all things considered. |
| tcx.sess.span_err(span, &fixup_err.to_string()); |
| return Err(ErrorReported) |
| } |
| }; |
| if predicates.has_local_value() { |
| // FIXME: shouldn't we, you know, actually report an error here? or an ICE? |
| Err(ErrorReported) |
| } else { |
| Ok(predicates) |
| } |
| }) |
| } |
| |
| // FIXME: this is gonna need to be removed ... |
| /// Normalizes the parameter environment, reporting errors if they occur. |
| pub fn normalize_param_env_or_error<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| region_context: DefId, |
| unnormalized_env: ty::ParamEnv<'tcx>, |
| cause: ObligationCause<'tcx>, |
| ) -> ty::ParamEnv<'tcx> { |
| // I'm not wild about reporting errors here; I'd prefer to |
| // have the errors get reported at a defined place (e.g., |
| // during typeck). Instead I have all parameter |
| // environments, in effect, going through this function |
| // and hence potentially reporting errors. This ensures of |
| // course that we never forget to normalize (the |
| // alternative seemed like it would involve a lot of |
| // manual invocations of this fn -- and then we'd have to |
| // deal with the errors at each of those sites). |
| // |
| // In any case, in practice, typeck constructs all the |
| // parameter environments once for every fn as it goes, |
| // and errors will get reported then; so after typeck we |
| // can be sure that no errors should occur. |
| |
| debug!("normalize_param_env_or_error(region_context={:?}, unnormalized_env={:?}, cause={:?})", |
| region_context, unnormalized_env, cause); |
| |
| let mut predicates: Vec<_> = |
| util::elaborate_predicates(tcx, unnormalized_env.caller_bounds.to_vec()) |
| .collect(); |
| |
| debug!("normalize_param_env_or_error: elaborated-predicates={:?}", |
| predicates); |
| |
| let elaborated_env = ty::ParamEnv::new( |
| tcx.intern_predicates(&predicates), |
| unnormalized_env.reveal, |
| unnormalized_env.def_id |
| ); |
| |
| // HACK: we are trying to normalize the param-env inside *itself*. The problem is that |
| // normalization expects its param-env to be already normalized, which means we have |
| // a circularity. |
| // |
| // The way we handle this is by normalizing the param-env inside an unnormalized version |
| // of the param-env, which means that if the param-env contains unnormalized projections, |
| // we'll have some normalization failures. This is unfortunate. |
| // |
| // Lazy normalization would basically handle this by treating just the |
| // normalizing-a-trait-ref-requires-itself cycles as evaluation failures. |
| // |
| // Inferred outlives bounds can create a lot of `TypeOutlives` predicates for associated |
| // types, so to make the situation less bad, we normalize all the predicates *but* |
| // the `TypeOutlives` predicates first inside the unnormalized parameter environment, and |
| // then we normalize the `TypeOutlives` bounds inside the normalized parameter environment. |
| // |
| // This works fairly well because trait matching does not actually care about param-env |
| // TypeOutlives predicates - these are normally used by regionck. |
| let outlives_predicates: Vec<_> = predicates.drain_filter(|predicate| { |
| match predicate { |
| ty::Predicate::TypeOutlives(..) => true, |
| _ => false |
| } |
| }).collect(); |
| |
| debug!("normalize_param_env_or_error: predicates=(non-outlives={:?}, outlives={:?})", |
| predicates, outlives_predicates); |
| let non_outlives_predicates = |
| match do_normalize_predicates(tcx, region_context, cause.clone(), |
| elaborated_env, predicates) { |
| Ok(predicates) => predicates, |
| // An unnormalized env is better than nothing. |
| Err(ErrorReported) => { |
| debug!("normalize_param_env_or_error: errored resolving non-outlives predicates"); |
| return elaborated_env |
| } |
| }; |
| |
| debug!("normalize_param_env_or_error: non-outlives predicates={:?}", non_outlives_predicates); |
| |
| // Not sure whether it is better to include the unnormalized TypeOutlives predicates |
| // here. I believe they should not matter, because we are ignoring TypeOutlives param-env |
| // predicates here anyway. Keeping them here anyway because it seems safer. |
| let outlives_env: Vec<_> = |
| non_outlives_predicates.iter().chain(&outlives_predicates).cloned().collect(); |
| let outlives_env = ty::ParamEnv::new( |
| tcx.intern_predicates(&outlives_env), |
| unnormalized_env.reveal, |
| None |
| ); |
| let outlives_predicates = |
| match do_normalize_predicates(tcx, region_context, cause, |
| outlives_env, outlives_predicates) { |
| Ok(predicates) => predicates, |
| // An unnormalized env is better than nothing. |
| Err(ErrorReported) => { |
| debug!("normalize_param_env_or_error: errored resolving outlives predicates"); |
| return elaborated_env |
| } |
| }; |
| debug!("normalize_param_env_or_error: outlives predicates={:?}", outlives_predicates); |
| |
| let mut predicates = non_outlives_predicates; |
| predicates.extend(outlives_predicates); |
| debug!("normalize_param_env_or_error: final predicates={:?}", predicates); |
| ty::ParamEnv::new( |
| tcx.intern_predicates(&predicates), |
| unnormalized_env.reveal, |
| unnormalized_env.def_id |
| ) |
| } |
| |
| pub fn fully_normalize<'a, 'tcx, T>( |
| infcx: &InferCtxt<'a, 'tcx>, |
| mut fulfill_cx: FulfillmentContext<'tcx>, |
| cause: ObligationCause<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| value: &T, |
| ) -> Result<T, Vec<FulfillmentError<'tcx>>> |
| where |
| T: TypeFoldable<'tcx>, |
| { |
| debug!("fully_normalize_with_fulfillcx(value={:?})", value); |
| let selcx = &mut SelectionContext::new(infcx); |
| let Normalized { value: normalized_value, obligations } = |
| project::normalize(selcx, param_env, cause, value); |
| debug!("fully_normalize: normalized_value={:?} obligations={:?}", |
| normalized_value, |
| obligations); |
| for obligation in obligations { |
| fulfill_cx.register_predicate_obligation(selcx.infcx(), obligation); |
| } |
| |
| debug!("fully_normalize: select_all_or_error start"); |
| fulfill_cx.select_all_or_error(infcx)?; |
| debug!("fully_normalize: select_all_or_error complete"); |
| let resolved_value = infcx.resolve_vars_if_possible(&normalized_value); |
| debug!("fully_normalize: resolved_value={:?}", resolved_value); |
| Ok(resolved_value) |
| } |
| |
| /// Normalizes the predicates and checks whether they hold in an empty |
| /// environment. If this returns false, then either normalize |
| /// encountered an error or one of the predicates did not hold. Used |
| /// when creating vtables to check for unsatisfiable methods. |
| fn normalize_and_test_predicates<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| predicates: Vec<ty::Predicate<'tcx>>, |
| ) -> bool { |
| debug!("normalize_and_test_predicates(predicates={:?})", |
| predicates); |
| |
| let result = tcx.infer_ctxt().enter(|infcx| { |
| let param_env = ty::ParamEnv::reveal_all(); |
| let mut selcx = SelectionContext::new(&infcx); |
| let mut fulfill_cx = FulfillmentContext::new(); |
| let cause = ObligationCause::dummy(); |
| let Normalized { value: predicates, obligations } = |
| normalize(&mut selcx, param_env, cause.clone(), &predicates); |
| for obligation in obligations { |
| fulfill_cx.register_predicate_obligation(&infcx, obligation); |
| } |
| for predicate in predicates { |
| let obligation = Obligation::new(cause.clone(), param_env, predicate); |
| fulfill_cx.register_predicate_obligation(&infcx, obligation); |
| } |
| |
| fulfill_cx.select_all_or_error(&infcx).is_ok() |
| }); |
| debug!("normalize_and_test_predicates(predicates={:?}) = {:?}", |
| predicates, result); |
| result |
| } |
| |
| fn substitute_normalize_and_test_predicates<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| key: (DefId, SubstsRef<'tcx>), |
| ) -> bool { |
| debug!("substitute_normalize_and_test_predicates(key={:?})", |
| key); |
| |
| let predicates = tcx.predicates_of(key.0).instantiate(tcx, key.1).predicates; |
| let result = normalize_and_test_predicates(tcx, predicates); |
| |
| debug!("substitute_normalize_and_test_predicates(key={:?}) = {:?}", |
| key, result); |
| result |
| } |
| |
| /// Given a trait `trait_ref`, iterates the vtable entries |
| /// that come from `trait_ref`, including its supertraits. |
| #[inline] // FIXME(#35870): avoid closures being unexported due to `impl Trait`. |
| fn vtable_methods<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| trait_ref: ty::PolyTraitRef<'tcx>, |
| ) -> &'tcx [Option<(DefId, SubstsRef<'tcx>)>] { |
| debug!("vtable_methods({:?})", trait_ref); |
| |
| tcx.arena.alloc_from_iter( |
| supertraits(tcx, trait_ref).flat_map(move |trait_ref| { |
| let trait_methods = tcx.associated_items(trait_ref.def_id()) |
| .filter(|item| item.kind == ty::AssocKind::Method); |
| |
| // Now list each method's DefId and InternalSubsts (for within its trait). |
| // If the method can never be called from this object, produce None. |
| trait_methods.map(move |trait_method| { |
| debug!("vtable_methods: trait_method={:?}", trait_method); |
| let def_id = trait_method.def_id; |
| |
| // Some methods cannot be called on an object; skip those. |
| if !tcx.is_vtable_safe_method(trait_ref.def_id(), &trait_method) { |
| debug!("vtable_methods: not vtable safe"); |
| return None; |
| } |
| |
| // the method may have some early-bound lifetimes, add |
| // regions for those |
| let substs = trait_ref.map_bound(|trait_ref| |
| InternalSubsts::for_item(tcx, def_id, |param, _| |
| match param.kind { |
| GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(), |
| GenericParamDefKind::Type { .. } | |
| GenericParamDefKind::Const => { |
| trait_ref.substs[param.index as usize] |
| } |
| } |
| ) |
| ); |
| |
| // the trait type may have higher-ranked lifetimes in it; |
| // so erase them if they appear, so that we get the type |
| // at some particular call site |
| let substs = tcx.normalize_erasing_late_bound_regions( |
| ty::ParamEnv::reveal_all(), |
| &substs |
| ); |
| |
| // It's possible that the method relies on where clauses that |
| // do not hold for this particular set of type parameters. |
| // Note that this method could then never be called, so we |
| // do not want to try and codegen it, in that case (see #23435). |
| let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs); |
| if !normalize_and_test_predicates(tcx, predicates.predicates) { |
| debug!("vtable_methods: predicates do not hold"); |
| return None; |
| } |
| |
| Some((def_id, substs)) |
| }) |
| }) |
| ) |
| } |
| |
| impl<'tcx, O> Obligation<'tcx, O> { |
| pub fn new(cause: ObligationCause<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| predicate: O) |
| -> Obligation<'tcx, O> |
| { |
| Obligation { cause, param_env, recursion_depth: 0, predicate } |
| } |
| |
| fn with_depth(cause: ObligationCause<'tcx>, |
| recursion_depth: usize, |
| param_env: ty::ParamEnv<'tcx>, |
| predicate: O) |
| -> Obligation<'tcx, O> |
| { |
| Obligation { cause, param_env, recursion_depth, predicate } |
| } |
| |
| pub fn misc(span: Span, |
| body_id: hir::HirId, |
| param_env: ty::ParamEnv<'tcx>, |
| trait_ref: O) |
| -> Obligation<'tcx, O> { |
| Obligation::new(ObligationCause::misc(span, body_id), param_env, trait_ref) |
| } |
| |
| pub fn with<P>(&self, value: P) -> Obligation<'tcx,P> { |
| Obligation { cause: self.cause.clone(), |
| param_env: self.param_env, |
| recursion_depth: self.recursion_depth, |
| predicate: value } |
| } |
| } |
| |
| impl<'tcx> ObligationCause<'tcx> { |
| #[inline] |
| pub fn new(span: Span, |
| body_id: hir::HirId, |
| code: ObligationCauseCode<'tcx>) |
| -> ObligationCause<'tcx> { |
| ObligationCause { span, body_id, code } |
| } |
| |
| pub fn misc(span: Span, body_id: hir::HirId) -> ObligationCause<'tcx> { |
| ObligationCause { span, body_id, code: MiscObligation } |
| } |
| |
| pub fn dummy() -> ObligationCause<'tcx> { |
| ObligationCause { span: DUMMY_SP, body_id: hir::CRATE_HIR_ID, code: MiscObligation } |
| } |
| } |
| |
| impl<'tcx, N> Vtable<'tcx, N> { |
| pub fn nested_obligations(self) -> Vec<N> { |
| match self { |
| VtableImpl(i) => i.nested, |
| VtableParam(n) => n, |
| VtableBuiltin(i) => i.nested, |
| VtableAutoImpl(d) => d.nested, |
| VtableClosure(c) => c.nested, |
| VtableGenerator(c) => c.nested, |
| VtableObject(d) => d.nested, |
| VtableFnPointer(d) => d.nested, |
| VtableTraitAlias(d) => d.nested, |
| } |
| } |
| |
| pub fn map<M, F>(self, f: F) -> Vtable<'tcx, M> where F: FnMut(N) -> M { |
| match self { |
| VtableImpl(i) => VtableImpl(VtableImplData { |
| impl_def_id: i.impl_def_id, |
| substs: i.substs, |
| nested: i.nested.into_iter().map(f).collect(), |
| }), |
| VtableParam(n) => VtableParam(n.into_iter().map(f).collect()), |
| VtableBuiltin(i) => VtableBuiltin(VtableBuiltinData { |
| nested: i.nested.into_iter().map(f).collect(), |
| }), |
| VtableObject(o) => VtableObject(VtableObjectData { |
| upcast_trait_ref: o.upcast_trait_ref, |
| vtable_base: o.vtable_base, |
| nested: o.nested.into_iter().map(f).collect(), |
| }), |
| VtableAutoImpl(d) => VtableAutoImpl(VtableAutoImplData { |
| trait_def_id: d.trait_def_id, |
| nested: d.nested.into_iter().map(f).collect(), |
| }), |
| VtableClosure(c) => VtableClosure(VtableClosureData { |
| closure_def_id: c.closure_def_id, |
| substs: c.substs, |
| nested: c.nested.into_iter().map(f).collect(), |
| }), |
| VtableGenerator(c) => VtableGenerator(VtableGeneratorData { |
| generator_def_id: c.generator_def_id, |
| substs: c.substs, |
| nested: c.nested.into_iter().map(f).collect(), |
| }), |
| VtableFnPointer(p) => VtableFnPointer(VtableFnPointerData { |
| fn_ty: p.fn_ty, |
| nested: p.nested.into_iter().map(f).collect(), |
| }), |
| VtableTraitAlias(d) => VtableTraitAlias(VtableTraitAliasData { |
| alias_def_id: d.alias_def_id, |
| substs: d.substs, |
| nested: d.nested.into_iter().map(f).collect(), |
| }), |
| } |
| } |
| } |
| |
| impl<'tcx> FulfillmentError<'tcx> { |
| fn new(obligation: PredicateObligation<'tcx>, |
| code: FulfillmentErrorCode<'tcx>) |
| -> FulfillmentError<'tcx> |
| { |
| FulfillmentError { obligation: obligation, code: code } |
| } |
| } |
| |
| impl<'tcx> TraitObligation<'tcx> { |
| fn self_ty(&self) -> ty::Binder<Ty<'tcx>> { |
| self.predicate.map_bound(|p| p.self_ty()) |
| } |
| } |
| |
| pub fn provide(providers: &mut ty::query::Providers<'_>) { |
| *providers = ty::query::Providers { |
| is_object_safe: object_safety::is_object_safe_provider, |
| specialization_graph_of: specialize::specialization_graph_provider, |
| specializes: specialize::specializes, |
| codegen_fulfill_obligation: codegen::codegen_fulfill_obligation, |
| vtable_methods, |
| substitute_normalize_and_test_predicates, |
| ..*providers |
| }; |
| } |
| |
| pub trait ExClauseFold<'tcx> |
| where |
| Self: chalk_engine::context::Context + Clone, |
| { |
| fn fold_ex_clause_with<F: TypeFolder<'tcx>>( |
| ex_clause: &chalk_engine::ExClause<Self>, |
| folder: &mut F, |
| ) -> chalk_engine::ExClause<Self>; |
| |
| fn visit_ex_clause_with<V: TypeVisitor<'tcx>>( |
| ex_clause: &chalk_engine::ExClause<Self>, |
| visitor: &mut V, |
| ) -> bool; |
| } |
| |
| pub trait ChalkContextLift<'tcx> |
| where |
| Self: chalk_engine::context::Context + Clone, |
| { |
| type LiftedExClause: Debug + 'tcx; |
| type LiftedDelayedLiteral: Debug + 'tcx; |
| type LiftedLiteral: Debug + 'tcx; |
| |
| fn lift_ex_clause_to_tcx( |
| ex_clause: &chalk_engine::ExClause<Self>, |
| tcx: TyCtxt<'tcx>, |
| ) -> Option<Self::LiftedExClause>; |
| |
| fn lift_delayed_literal_to_tcx( |
| ex_clause: &chalk_engine::DelayedLiteral<Self>, |
| tcx: TyCtxt<'tcx>, |
| ) -> Option<Self::LiftedDelayedLiteral>; |
| |
| fn lift_literal_to_tcx( |
| ex_clause: &chalk_engine::Literal<Self>, |
| tcx: TyCtxt<'tcx>, |
| ) -> Option<Self::LiftedLiteral>; |
| } |
