1 //! Defines how the compiler represents types internally.
3 //! Two important entities in this module are:
5 //! - [`rustc_middle::ty::Ty`], used to represent the semantics of a type.
6 //! - [`rustc_middle::ty::TyCtxt`], the central data structure in the compiler.
8 //! For more information, see ["The `ty` module: representing types"] in the rustc-dev-guide.
10 //! ["The `ty` module: representing types"]: https://rustc-dev-guide.rust-lang.org/ty.html
12 #![allow(rustc::usage_of_ty_tykind)]
14 pub use self::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable};
15 pub use self::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
16 pub use self::AssocItemContainer::*;
17 pub use self::BorrowKind::*;
18 pub use self::IntVarValue::*;
19 pub use self::Variance::*;
20 use crate::error::{OpaqueHiddenTypeMismatch, TypeMismatchReason};
21 use crate::metadata::ModChild;
22 use crate::middle::privacy::EffectiveVisibilities;
23 use crate::mir::{Body, GeneratorLayout};
24 use crate::traits::{self, Reveal};
26 use crate::ty::fast_reject::SimplifiedType;
27 use crate::ty::util::Discr;
32 use rustc_ast::node_id::NodeMap;
33 use rustc_attr as attr;
34 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
35 use rustc_data_structures::intern::Interned;
36 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
37 use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
39 use rustc_hir::def::{CtorKind, CtorOf, DefKind, LifetimeRes, Res};
40 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LocalDefIdMap};
42 use rustc_index::vec::IndexVec;
43 use rustc_macros::HashStable;
44 use rustc_query_system::ich::StableHashingContext;
45 use rustc_serialize::{Decodable, Encodable};
46 use rustc_session::cstore::Untracked;
47 use rustc_span::hygiene::MacroKind;
48 use rustc_span::symbol::{kw, sym, Ident, Symbol};
49 use rustc_span::{ExpnId, Span};
50 use rustc_target::abi::{Align, Integer, IntegerType, VariantIdx};
51 pub use rustc_target::abi::{ReprFlags, ReprOptions};
52 use rustc_type_ir::WithCachedTypeInfo;
57 use std::hash::{Hash, Hasher};
58 use std::marker::PhantomData;
60 use std::num::NonZeroUsize;
61 use std::ops::ControlFlow;
64 pub use crate::ty::diagnostics::*;
65 pub use rustc_type_ir::AliasKind::*;
66 pub use rustc_type_ir::DynKind::*;
67 pub use rustc_type_ir::InferTy::*;
68 pub use rustc_type_ir::RegionKind::*;
69 pub use rustc_type_ir::TyKind::*;
70 pub use rustc_type_ir::*;
72 pub use self::binding::BindingMode;
73 pub use self::binding::BindingMode::*;
74 pub use self::closure::{
75 is_ancestor_or_same_capture, place_to_string_for_capture, BorrowKind, CaptureInfo,
76 CapturedPlace, ClosureKind, MinCaptureInformationMap, MinCaptureList,
77 RootVariableMinCaptureList, UpvarCapture, UpvarCaptureMap, UpvarId, UpvarListMap, UpvarPath,
80 pub use self::consts::{
81 Const, ConstData, ConstInt, ConstKind, Expr, InferConst, ScalarInt, UnevaluatedConst, ValTree,
83 pub use self::context::{
84 tls, CtxtInterners, DeducedParamAttrs, FreeRegionInfo, GlobalCtxt, Lift, OnDiskCache, TyCtxt,
87 pub use self::instance::{Instance, InstanceDef, ShortInstance, UnusedGenericParams};
88 pub use self::list::List;
89 pub use self::parameterized::ParameterizedOverTcx;
90 pub use self::rvalue_scopes::RvalueScopes;
91 pub use self::sty::BoundRegionKind::*;
93 AliasTy, Article, Binder, BoundRegion, BoundRegionKind, BoundTy, BoundTyKind, BoundVar,
94 BoundVariableKind, CanonicalPolyFnSig, ClosureSubsts, ClosureSubstsParts, ConstVid,
95 EarlyBoundRegion, ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FnSig,
96 FreeRegion, GenSig, GeneratorSubsts, GeneratorSubstsParts, InlineConstSubsts,
97 InlineConstSubstsParts, ParamConst, ParamTy, PolyExistentialPredicate,
98 PolyExistentialProjection, PolyExistentialTraitRef, PolyFnSig, PolyGenSig, PolyTraitRef,
99 Region, RegionKind, RegionVid, TraitRef, TyKind, TypeAndMut, UpvarSubsts, VarianceDiagInfo,
101 pub use self::trait_def::TraitDef;
102 pub use self::typeck_results::{
103 CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
104 GeneratorDiagnosticData, GeneratorInteriorTypeCause, TypeckResults, UserType,
105 UserTypeAnnotationIndex,
109 pub mod abstract_const;
118 pub mod inhabitedness;
120 pub mod normalize_erasing_regions;
145 mod structural_impls;
151 pub type RegisteredTools = FxHashSet<Ident>;
153 pub struct ResolverOutputs {
154 pub global_ctxt: ResolverGlobalCtxt,
155 pub ast_lowering: ResolverAstLowering,
156 pub untracked: Untracked,
160 pub struct ResolverGlobalCtxt {
161 pub visibilities: FxHashMap<LocalDefId, Visibility>,
162 /// This field is used to decide whether we should make `PRIVATE_IN_PUBLIC` a hard error.
163 pub has_pub_restricted: bool,
164 /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
165 pub expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
166 pub effective_visibilities: EffectiveVisibilities,
167 pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
168 pub maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
169 pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
170 pub reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
171 pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
172 /// Extern prelude entries. The value is `true` if the entry was introduced
173 /// via `extern crate` item and not `--extern` option or compiler built-in.
174 pub extern_prelude: FxHashMap<Symbol, bool>,
175 pub main_def: Option<MainDefinition>,
176 pub trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
177 /// A list of proc macro LocalDefIds, written out in the order in which
178 /// they are declared in the static array generated by proc_macro_harness.
179 pub proc_macros: Vec<LocalDefId>,
180 /// Mapping from ident span to path span for paths that don't exist as written, but that
181 /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
182 pub confused_type_with_std_module: FxHashMap<Span, Span>,
183 pub registered_tools: RegisteredTools,
186 /// Resolutions that should only be used for lowering.
187 /// This struct is meant to be consumed by lowering.
189 pub struct ResolverAstLowering {
190 pub legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
192 /// Resolutions for nodes that have a single resolution.
193 pub partial_res_map: NodeMap<hir::def::PartialRes>,
194 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
195 pub import_res_map: NodeMap<hir::def::PerNS<Option<Res<ast::NodeId>>>>,
196 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
197 pub label_res_map: NodeMap<ast::NodeId>,
198 /// Resolutions for lifetimes.
199 pub lifetimes_res_map: NodeMap<LifetimeRes>,
200 /// Lifetime parameters that lowering will have to introduce.
201 pub extra_lifetime_params_map: NodeMap<Vec<(Ident, ast::NodeId, LifetimeRes)>>,
203 pub next_node_id: ast::NodeId,
205 pub node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
206 pub def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
208 pub trait_map: NodeMap<Vec<hir::TraitCandidate>>,
209 /// A small map keeping true kinds of built-in macros that appear to be fn-like on
210 /// the surface (`macro` items in libcore), but are actually attributes or derives.
211 pub builtin_macro_kinds: FxHashMap<LocalDefId, MacroKind>,
212 /// List functions and methods for which lifetime elision was successful.
213 pub lifetime_elision_allowed: FxHashSet<ast::NodeId>,
216 #[derive(Clone, Copy, Debug)]
217 pub struct MainDefinition {
218 pub res: Res<ast::NodeId>,
223 impl MainDefinition {
224 pub fn opt_fn_def_id(self) -> Option<DefId> {
225 if let Res::Def(DefKind::Fn, def_id) = self.res { Some(def_id) } else { None }
229 /// The "header" of an impl is everything outside the body: a Self type, a trait
230 /// ref (in the case of a trait impl), and a set of predicates (from the
231 /// bounds / where-clauses).
232 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
233 pub struct ImplHeader<'tcx> {
234 pub impl_def_id: DefId,
235 pub self_ty: Ty<'tcx>,
236 pub trait_ref: Option<TraitRef<'tcx>>,
237 pub predicates: Vec<Predicate<'tcx>>,
240 #[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable)]
241 pub enum ImplSubject<'tcx> {
242 Trait(TraitRef<'tcx>),
246 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable, Debug)]
247 #[derive(TypeFoldable, TypeVisitable)]
248 pub enum ImplPolarity {
249 /// `impl Trait for Type`
251 /// `impl !Trait for Type`
253 /// `#[rustc_reservation_impl] impl Trait for Type`
255 /// This is a "stability hack", not a real Rust feature.
256 /// See #64631 for details.
261 /// Flips polarity by turning `Positive` into `Negative` and `Negative` into `Positive`.
262 pub fn flip(&self) -> Option<ImplPolarity> {
264 ImplPolarity::Positive => Some(ImplPolarity::Negative),
265 ImplPolarity::Negative => Some(ImplPolarity::Positive),
266 ImplPolarity::Reservation => None,
271 impl fmt::Display for ImplPolarity {
272 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
274 Self::Positive => f.write_str("positive"),
275 Self::Negative => f.write_str("negative"),
276 Self::Reservation => f.write_str("reservation"),
281 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, Encodable, Decodable, HashStable)]
282 pub enum Visibility<Id = LocalDefId> {
283 /// Visible everywhere (including in other crates).
285 /// Visible only in the given crate-local module.
289 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
290 pub enum BoundConstness {
293 /// `T: ~const Trait`
295 /// Requires resolving to const only when we are in a const context.
299 impl BoundConstness {
300 /// Reduce `self` and `constness` to two possible combined states instead of four.
301 pub fn and(&mut self, constness: hir::Constness) -> hir::Constness {
302 match (constness, self) {
303 (hir::Constness::Const, BoundConstness::ConstIfConst) => hir::Constness::Const,
305 *this = BoundConstness::NotConst;
306 hir::Constness::NotConst
312 impl fmt::Display for BoundConstness {
313 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
315 Self::NotConst => f.write_str("normal"),
316 Self::ConstIfConst => f.write_str("`~const`"),
321 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, TyEncodable, TyDecodable, HashStable)]
322 #[derive(TypeFoldable, TypeVisitable)]
323 pub struct ClosureSizeProfileData<'tcx> {
324 /// Tuple containing the types of closure captures before the feature `capture_disjoint_fields`
325 pub before_feature_tys: Ty<'tcx>,
326 /// Tuple containing the types of closure captures after the feature `capture_disjoint_fields`
327 pub after_feature_tys: Ty<'tcx>,
330 pub trait DefIdTree: Copy {
331 fn opt_parent(self, id: DefId) -> Option<DefId>;
335 fn parent(self, id: DefId) -> DefId {
336 match self.opt_parent(id) {
338 // not `unwrap_or_else` to avoid breaking caller tracking
339 None => bug!("{id:?} doesn't have a parent"),
345 fn opt_local_parent(self, id: LocalDefId) -> Option<LocalDefId> {
346 self.opt_parent(id.to_def_id()).map(DefId::expect_local)
351 fn local_parent(self, id: LocalDefId) -> LocalDefId {
352 self.parent(id.to_def_id()).expect_local()
355 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
356 if descendant.krate != ancestor.krate {
360 while descendant != ancestor {
361 match self.opt_parent(descendant) {
362 Some(parent) => descendant = parent,
363 None => return false,
370 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
372 fn opt_parent(self, id: DefId) -> Option<DefId> {
373 self.def_key(id).parent.map(|index| DefId { index, ..id })
377 impl<Id> Visibility<Id> {
378 pub fn is_public(self) -> bool {
379 matches!(self, Visibility::Public)
382 pub fn map_id<OutId>(self, f: impl FnOnce(Id) -> OutId) -> Visibility<OutId> {
384 Visibility::Public => Visibility::Public,
385 Visibility::Restricted(id) => Visibility::Restricted(f(id)),
390 impl<Id: Into<DefId>> Visibility<Id> {
391 pub fn to_def_id(self) -> Visibility<DefId> {
392 self.map_id(Into::into)
395 /// Returns `true` if an item with this visibility is accessible from the given module.
396 pub fn is_accessible_from(self, module: impl Into<DefId>, tree: impl DefIdTree) -> bool {
398 // Public items are visible everywhere.
399 Visibility::Public => true,
400 Visibility::Restricted(id) => tree.is_descendant_of(module.into(), id.into()),
404 /// Returns `true` if this visibility is at least as accessible as the given visibility
405 pub fn is_at_least(self, vis: Visibility<impl Into<DefId>>, tree: impl DefIdTree) -> bool {
407 Visibility::Public => self.is_public(),
408 Visibility::Restricted(id) => self.is_accessible_from(id, tree),
413 impl Visibility<DefId> {
414 pub fn expect_local(self) -> Visibility {
415 self.map_id(|id| id.expect_local())
418 /// Returns `true` if this item is visible anywhere in the local crate.
419 pub fn is_visible_locally(self) -> bool {
421 Visibility::Public => true,
422 Visibility::Restricted(def_id) => def_id.is_local(),
427 /// The crate variances map is computed during typeck and contains the
428 /// variance of every item in the local crate. You should not use it
429 /// directly, because to do so will make your pass dependent on the
430 /// HIR of every item in the local crate. Instead, use
431 /// `tcx.variances_of()` to get the variance for a *particular*
433 #[derive(HashStable, Debug)]
434 pub struct CrateVariancesMap<'tcx> {
435 /// For each item with generics, maps to a vector of the variance
436 /// of its generics. If an item has no generics, it will have no
438 pub variances: DefIdMap<&'tcx [ty::Variance]>,
441 // Contains information needed to resolve types and (in the future) look up
442 // the types of AST nodes.
443 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
444 pub struct CReaderCacheKey {
445 pub cnum: Option<CrateNum>,
449 /// Use this rather than `TyKind`, whenever possible.
450 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)]
451 #[rustc_diagnostic_item = "Ty"]
452 #[rustc_pass_by_value]
453 pub struct Ty<'tcx>(Interned<'tcx, WithCachedTypeInfo<TyKind<'tcx>>>);
455 impl ty::EarlyBoundRegion {
456 /// Does this early bound region have a name? Early bound regions normally
457 /// always have names except when using anonymous lifetimes (`'_`).
458 pub fn has_name(&self) -> bool {
459 self.name != kw::UnderscoreLifetime && self.name != kw::Empty
463 /// Use this rather than `PredicateKind`, whenever possible.
464 #[derive(Clone, Copy, PartialEq, Eq, Hash, HashStable)]
465 #[rustc_pass_by_value]
466 pub struct Predicate<'tcx>(
467 Interned<'tcx, WithCachedTypeInfo<ty::Binder<'tcx, PredicateKind<'tcx>>>>,
470 impl<'tcx> Predicate<'tcx> {
471 /// Gets the inner `Binder<'tcx, PredicateKind<'tcx>>`.
473 pub fn kind(self) -> Binder<'tcx, PredicateKind<'tcx>> {
478 pub fn flags(self) -> TypeFlags {
483 pub fn outer_exclusive_binder(self) -> DebruijnIndex {
484 self.0.outer_exclusive_binder
487 /// Flips the polarity of a Predicate.
489 /// Given `T: Trait` predicate it returns `T: !Trait` and given `T: !Trait` returns `T: Trait`.
490 pub fn flip_polarity(self, tcx: TyCtxt<'tcx>) -> Option<Predicate<'tcx>> {
493 .map_bound(|kind| match kind {
494 PredicateKind::Clause(Clause::Trait(TraitPredicate {
498 })) => Some(PredicateKind::Clause(Clause::Trait(TraitPredicate {
501 polarity: polarity.flip()?,
508 Some(tcx.mk_predicate(kind))
511 pub fn without_const(mut self, tcx: TyCtxt<'tcx>) -> Self {
512 if let PredicateKind::Clause(Clause::Trait(TraitPredicate { trait_ref, constness, polarity })) = self.kind().skip_binder()
513 && constness != BoundConstness::NotConst
515 self = tcx.mk_predicate(self.kind().rebind(PredicateKind::Clause(Clause::Trait(TraitPredicate {
517 constness: BoundConstness::NotConst,
524 #[instrument(level = "debug", skip(tcx), ret)]
525 pub fn is_coinductive(self, tcx: TyCtxt<'tcx>) -> bool {
526 match self.kind().skip_binder() {
527 ty::PredicateKind::Clause(ty::Clause::Trait(data)) => {
528 tcx.trait_is_coinductive(data.def_id())
530 ty::PredicateKind::WellFormed(_) => true,
535 /// Whether this projection can be soundly normalized.
537 /// Wf predicates must not be normalized, as normalization
538 /// can remove required bounds which would cause us to
539 /// unsoundly accept some programs. See #91068.
541 pub fn allow_normalization(self) -> bool {
542 match self.kind().skip_binder() {
543 PredicateKind::WellFormed(_) => false,
544 PredicateKind::Clause(Clause::Trait(_))
545 | PredicateKind::Clause(Clause::RegionOutlives(_))
546 | PredicateKind::Clause(Clause::TypeOutlives(_))
547 | PredicateKind::Clause(Clause::Projection(_))
548 | PredicateKind::ObjectSafe(_)
549 | PredicateKind::ClosureKind(_, _, _)
550 | PredicateKind::Subtype(_)
551 | PredicateKind::Coerce(_)
552 | PredicateKind::ConstEvaluatable(_)
553 | PredicateKind::ConstEquate(_, _)
554 | PredicateKind::Ambiguous
555 | PredicateKind::TypeWellFormedFromEnv(_) => true,
560 impl rustc_errors::IntoDiagnosticArg for Predicate<'_> {
561 fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
562 rustc_errors::DiagnosticArgValue::Str(std::borrow::Cow::Owned(self.to_string()))
566 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
567 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
568 /// A clause is something that can appear in where bounds or be inferred
569 /// by implied bounds.
570 pub enum Clause<'tcx> {
571 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
572 /// the `Self` type of the trait reference and `A`, `B`, and `C`
573 /// would be the type parameters.
574 Trait(TraitPredicate<'tcx>),
577 RegionOutlives(RegionOutlivesPredicate<'tcx>),
580 TypeOutlives(TypeOutlivesPredicate<'tcx>),
582 /// `where <T as TraitRef>::Name == X`, approximately.
583 /// See the `ProjectionPredicate` struct for details.
584 Projection(ProjectionPredicate<'tcx>),
587 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
588 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
589 pub enum PredicateKind<'tcx> {
591 Clause(Clause<'tcx>),
593 /// No syntax: `T` well-formed.
594 WellFormed(GenericArg<'tcx>),
596 /// Trait must be object-safe.
599 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
600 /// for some substitutions `...` and `T` being a closure type.
601 /// Satisfied (or refuted) once we know the closure's kind.
602 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
606 /// This obligation is created most often when we have two
607 /// unresolved type variables and hence don't have enough
608 /// information to process the subtyping obligation yet.
609 Subtype(SubtypePredicate<'tcx>),
611 /// `T1` coerced to `T2`
613 /// Like a subtyping obligation, this is created most often
614 /// when we have two unresolved type variables and hence
615 /// don't have enough information to process the coercion
616 /// obligation yet. At the moment, we actually process coercions
617 /// very much like subtyping and don't handle the full coercion
619 Coerce(CoercePredicate<'tcx>),
621 /// Constant initializer must evaluate successfully.
622 ConstEvaluatable(ty::Const<'tcx>),
624 /// Constants must be equal. The first component is the const that is expected.
625 ConstEquate(Const<'tcx>, Const<'tcx>),
627 /// Represents a type found in the environment that we can use for implied bounds.
629 /// Only used for Chalk.
630 TypeWellFormedFromEnv(Ty<'tcx>),
632 /// A marker predicate that is always ambiguous.
633 /// Used for coherence to mark opaque types as possibly equal to each other but ambiguous.
637 /// The crate outlives map is computed during typeck and contains the
638 /// outlives of every item in the local crate. You should not use it
639 /// directly, because to do so will make your pass dependent on the
640 /// HIR of every item in the local crate. Instead, use
641 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
643 #[derive(HashStable, Debug)]
644 pub struct CratePredicatesMap<'tcx> {
645 /// For each struct with outlive bounds, maps to a vector of the
646 /// predicate of its outlive bounds. If an item has no outlives
647 /// bounds, it will have no entry.
648 pub predicates: FxHashMap<DefId, &'tcx [(Clause<'tcx>, Span)]>,
651 impl<'tcx> Predicate<'tcx> {
652 /// Performs a substitution suitable for going from a
653 /// poly-trait-ref to supertraits that must hold if that
654 /// poly-trait-ref holds. This is slightly different from a normal
655 /// substitution in terms of what happens with bound regions. See
656 /// lengthy comment below for details.
657 pub fn subst_supertrait(
660 trait_ref: &ty::PolyTraitRef<'tcx>,
661 ) -> Predicate<'tcx> {
662 // The interaction between HRTB and supertraits is not entirely
663 // obvious. Let me walk you (and myself) through an example.
665 // Let's start with an easy case. Consider two traits:
667 // trait Foo<'a>: Bar<'a,'a> { }
668 // trait Bar<'b,'c> { }
670 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
671 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
672 // knew that `Foo<'x>` (for any 'x) then we also know that
673 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
674 // normal substitution.
676 // In terms of why this is sound, the idea is that whenever there
677 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
678 // holds. So if there is an impl of `T:Foo<'a>` that applies to
679 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
682 // Another example to be careful of is this:
684 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
685 // trait Bar1<'b,'c> { }
687 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
688 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
689 // reason is similar to the previous example: any impl of
690 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
691 // basically we would want to collapse the bound lifetimes from
692 // the input (`trait_ref`) and the supertraits.
694 // To achieve this in practice is fairly straightforward. Let's
695 // consider the more complicated scenario:
697 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
698 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
699 // where both `'x` and `'b` would have a DB index of 1.
700 // The substitution from the input trait-ref is therefore going to be
701 // `'a => 'x` (where `'x` has a DB index of 1).
702 // - The supertrait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
703 // early-bound parameter and `'b' is a late-bound parameter with a
705 // - If we replace `'a` with `'x` from the input, it too will have
706 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
707 // just as we wanted.
709 // There is only one catch. If we just apply the substitution `'a
710 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
711 // adjust the DB index because we substituting into a binder (it
712 // tries to be so smart...) resulting in `for<'x> for<'b>
713 // Bar1<'x,'b>` (we have no syntax for this, so use your
714 // imagination). Basically the 'x will have DB index of 2 and 'b
715 // will have DB index of 1. Not quite what we want. So we apply
716 // the substitution to the *contents* of the trait reference,
717 // rather than the trait reference itself (put another way, the
718 // substitution code expects equal binding levels in the values
719 // from the substitution and the value being substituted into, and
720 // this trick achieves that).
722 // Working through the second example:
723 // trait_ref: for<'x> T: Foo1<'^0.0>; substs: [T, '^0.0]
724 // predicate: for<'b> Self: Bar1<'a, '^0.0>; substs: [Self, 'a, '^0.0]
725 // We want to end up with:
726 // for<'x, 'b> T: Bar1<'^0.0, '^0.1>
728 // 1) We must shift all bound vars in predicate by the length
729 // of trait ref's bound vars. So, we would end up with predicate like
730 // Self: Bar1<'a, '^0.1>
731 // 2) We can then apply the trait substs to this, ending up with
732 // T: Bar1<'^0.0, '^0.1>
733 // 3) Finally, to create the final bound vars, we concatenate the bound
734 // vars of the trait ref with those of the predicate:
736 let bound_pred = self.kind();
737 let pred_bound_vars = bound_pred.bound_vars();
738 let trait_bound_vars = trait_ref.bound_vars();
739 // 1) Self: Bar1<'a, '^0.0> -> Self: Bar1<'a, '^0.1>
741 tcx.shift_bound_var_indices(trait_bound_vars.len(), bound_pred.skip_binder());
742 // 2) Self: Bar1<'a, '^0.1> -> T: Bar1<'^0.0, '^0.1>
743 let new = EarlyBinder(shifted_pred).subst(tcx, trait_ref.skip_binder().substs);
744 // 3) ['x] + ['b] -> ['x, 'b]
746 tcx.mk_bound_variable_kinds(trait_bound_vars.iter().chain(pred_bound_vars));
747 tcx.reuse_or_mk_predicate(self, ty::Binder::bind_with_vars(new, bound_vars))
751 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
752 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
753 pub struct TraitPredicate<'tcx> {
754 pub trait_ref: TraitRef<'tcx>,
756 pub constness: BoundConstness,
758 /// If polarity is Positive: we are proving that the trait is implemented.
760 /// If polarity is Negative: we are proving that a negative impl of this trait
761 /// exists. (Note that coherence also checks whether negative impls of supertraits
762 /// exist via a series of predicates.)
764 /// If polarity is Reserved: that's a bug.
765 pub polarity: ImplPolarity,
768 pub type PolyTraitPredicate<'tcx> = ty::Binder<'tcx, TraitPredicate<'tcx>>;
770 impl<'tcx> TraitPredicate<'tcx> {
771 pub fn remap_constness(&mut self, param_env: &mut ParamEnv<'tcx>) {
772 *param_env = param_env.with_constness(self.constness.and(param_env.constness()))
775 /// Remap the constness of this predicate before emitting it for diagnostics.
776 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
777 // this is different to `remap_constness` that callees want to print this predicate
778 // in case of selection errors. `T: ~const Drop` bounds cannot end up here when the
779 // param_env is not const because it is always satisfied in non-const contexts.
780 if let hir::Constness::NotConst = param_env.constness() {
781 self.constness = ty::BoundConstness::NotConst;
785 pub fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self {
786 Self { trait_ref: self.trait_ref.with_self_ty(tcx, self_ty), ..self }
789 pub fn def_id(self) -> DefId {
790 self.trait_ref.def_id
793 pub fn self_ty(self) -> Ty<'tcx> {
794 self.trait_ref.self_ty()
798 pub fn is_const_if_const(self) -> bool {
799 self.constness == BoundConstness::ConstIfConst
802 pub fn is_constness_satisfied_by(self, constness: hir::Constness) -> bool {
803 match (self.constness, constness) {
804 (BoundConstness::NotConst, _)
805 | (BoundConstness::ConstIfConst, hir::Constness::Const) => true,
806 (BoundConstness::ConstIfConst, hir::Constness::NotConst) => false,
810 pub fn without_const(mut self) -> Self {
811 self.constness = BoundConstness::NotConst;
816 impl<'tcx> PolyTraitPredicate<'tcx> {
817 pub fn def_id(self) -> DefId {
818 // Ok to skip binder since trait `DefId` does not care about regions.
819 self.skip_binder().def_id()
822 pub fn self_ty(self) -> ty::Binder<'tcx, Ty<'tcx>> {
823 self.map_bound(|trait_ref| trait_ref.self_ty())
826 /// Remap the constness of this predicate before emitting it for diagnostics.
827 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
828 *self = self.map_bound(|mut p| {
829 p.remap_constness_diag(param_env);
835 pub fn is_const_if_const(self) -> bool {
836 self.skip_binder().is_const_if_const()
841 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
842 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
843 pub struct OutlivesPredicate<A, B>(pub A, pub B);
844 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
845 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
846 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<'tcx, RegionOutlivesPredicate<'tcx>>;
847 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<'tcx, TypeOutlivesPredicate<'tcx>>;
849 /// Encodes that `a` must be a subtype of `b`. The `a_is_expected` flag indicates
850 /// whether the `a` type is the type that we should label as "expected" when
851 /// presenting user diagnostics.
852 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
853 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
854 pub struct SubtypePredicate<'tcx> {
855 pub a_is_expected: bool,
859 pub type PolySubtypePredicate<'tcx> = ty::Binder<'tcx, SubtypePredicate<'tcx>>;
861 /// Encodes that we have to coerce *from* the `a` type to the `b` type.
862 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
863 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
864 pub struct CoercePredicate<'tcx> {
868 pub type PolyCoercePredicate<'tcx> = ty::Binder<'tcx, CoercePredicate<'tcx>>;
870 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
871 pub struct Term<'tcx> {
873 marker: PhantomData<(Ty<'tcx>, Const<'tcx>)>,
876 impl Debug for Term<'_> {
877 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
878 let data = if let Some(ty) = self.ty() {
879 format!("Term::Ty({:?})", ty)
880 } else if let Some(ct) = self.ct() {
881 format!("Term::Ct({:?})", ct)
889 impl<'tcx> From<Ty<'tcx>> for Term<'tcx> {
890 fn from(ty: Ty<'tcx>) -> Self {
891 TermKind::Ty(ty).pack()
895 impl<'tcx> From<Const<'tcx>> for Term<'tcx> {
896 fn from(c: Const<'tcx>) -> Self {
897 TermKind::Const(c).pack()
901 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Term<'tcx> {
902 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
903 self.unpack().hash_stable(hcx, hasher);
907 impl<'tcx> TypeFoldable<'tcx> for Term<'tcx> {
908 fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
909 Ok(self.unpack().try_fold_with(folder)?.pack())
913 impl<'tcx> TypeVisitable<'tcx> for Term<'tcx> {
914 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
915 self.unpack().visit_with(visitor)
919 impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for Term<'tcx> {
920 fn encode(&self, e: &mut E) {
921 self.unpack().encode(e)
925 impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for Term<'tcx> {
926 fn decode(d: &mut D) -> Self {
927 let res: TermKind<'tcx> = Decodable::decode(d);
932 impl<'tcx> Term<'tcx> {
934 pub fn unpack(self) -> TermKind<'tcx> {
935 let ptr = self.ptr.get();
936 // SAFETY: use of `Interned::new_unchecked` here is ok because these
937 // pointers were originally created from `Interned` types in `pack()`,
938 // and this is just going in the other direction.
940 match ptr & TAG_MASK {
941 TYPE_TAG => TermKind::Ty(Ty(Interned::new_unchecked(
942 &*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyKind<'tcx>>),
944 CONST_TAG => TermKind::Const(ty::Const(Interned::new_unchecked(
945 &*((ptr & !TAG_MASK) as *const ty::ConstData<'tcx>),
947 _ => core::intrinsics::unreachable(),
952 pub fn ty(&self) -> Option<Ty<'tcx>> {
953 if let TermKind::Ty(ty) = self.unpack() { Some(ty) } else { None }
956 pub fn ct(&self) -> Option<Const<'tcx>> {
957 if let TermKind::Const(c) = self.unpack() { Some(c) } else { None }
960 pub fn into_arg(self) -> GenericArg<'tcx> {
961 match self.unpack() {
962 TermKind::Ty(ty) => ty.into(),
963 TermKind::Const(c) => c.into(),
968 const TAG_MASK: usize = 0b11;
969 const TYPE_TAG: usize = 0b00;
970 const CONST_TAG: usize = 0b01;
972 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
973 #[derive(HashStable, TypeFoldable, TypeVisitable)]
974 pub enum TermKind<'tcx> {
979 impl<'tcx> TermKind<'tcx> {
981 fn pack(self) -> Term<'tcx> {
982 let (tag, ptr) = match self {
983 TermKind::Ty(ty) => {
984 // Ensure we can use the tag bits.
985 assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
986 (TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyKind<'tcx>> as usize)
988 TermKind::Const(ct) => {
989 // Ensure we can use the tag bits.
990 assert_eq!(mem::align_of_val(&*ct.0.0) & TAG_MASK, 0);
991 (CONST_TAG, ct.0.0 as *const ty::ConstData<'tcx> as usize)
995 Term { ptr: unsafe { NonZeroUsize::new_unchecked(ptr | tag) }, marker: PhantomData }
999 /// This kind of predicate has no *direct* correspondent in the
1000 /// syntax, but it roughly corresponds to the syntactic forms:
1002 /// 1. `T: TraitRef<..., Item = Type>`
1003 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1005 /// In particular, form #1 is "desugared" to the combination of a
1006 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1007 /// predicates. Form #2 is a broader form in that it also permits
1008 /// equality between arbitrary types. Processing an instance of
1009 /// Form #2 eventually yields one of these `ProjectionPredicate`
1010 /// instances to normalize the LHS.
1011 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
1012 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
1013 pub struct ProjectionPredicate<'tcx> {
1014 pub projection_ty: AliasTy<'tcx>,
1015 pub term: Term<'tcx>,
1018 impl<'tcx> ProjectionPredicate<'tcx> {
1019 pub fn self_ty(self) -> Ty<'tcx> {
1020 self.projection_ty.self_ty()
1023 pub fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ProjectionPredicate<'tcx> {
1024 Self { projection_ty: self.projection_ty.with_self_ty(tcx, self_ty), ..self }
1027 pub fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId {
1028 self.projection_ty.trait_def_id(tcx)
1031 pub fn def_id(self) -> DefId {
1032 self.projection_ty.def_id
1036 pub type PolyProjectionPredicate<'tcx> = Binder<'tcx, ProjectionPredicate<'tcx>>;
1038 impl<'tcx> PolyProjectionPredicate<'tcx> {
1039 /// Returns the `DefId` of the trait of the associated item being projected.
1041 pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
1042 self.skip_binder().projection_ty.trait_def_id(tcx)
1045 /// Get the [PolyTraitRef] required for this projection to be well formed.
1046 /// Note that for generic associated types the predicates of the associated
1047 /// type also need to be checked.
1049 pub fn required_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
1050 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1051 // `self.0.trait_ref` is permitted to have escaping regions.
1052 // This is because here `self` has a `Binder` and so does our
1053 // return value, so we are preserving the number of binding
1055 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1058 pub fn term(&self) -> Binder<'tcx, Term<'tcx>> {
1059 self.map_bound(|predicate| predicate.term)
1062 /// The `DefId` of the `TraitItem` for the associated type.
1064 /// Note that this is not the `DefId` of the `TraitRef` containing this
1065 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1066 pub fn projection_def_id(&self) -> DefId {
1067 // Ok to skip binder since trait `DefId` does not care about regions.
1068 self.skip_binder().projection_ty.def_id
1072 pub trait ToPolyTraitRef<'tcx> {
1073 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1076 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1077 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1078 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1082 pub trait ToPredicate<'tcx, P = Predicate<'tcx>> {
1083 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> P;
1086 impl<'tcx, T> ToPredicate<'tcx, T> for T {
1087 fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T {
1092 impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, PredicateKind<'tcx>> {
1094 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1095 tcx.mk_predicate(self)
1099 impl<'tcx> ToPredicate<'tcx> for Clause<'tcx> {
1101 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1102 tcx.mk_predicate(ty::Binder::dummy(ty::PredicateKind::Clause(self)))
1106 impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, TraitRef<'tcx>> {
1108 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1109 let pred: PolyTraitPredicate<'tcx> = self.to_predicate(tcx);
1110 pred.to_predicate(tcx)
1114 impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for Binder<'tcx, TraitRef<'tcx>> {
1116 fn to_predicate(self, _: TyCtxt<'tcx>) -> PolyTraitPredicate<'tcx> {
1117 self.map_bound(|trait_ref| TraitPredicate {
1119 constness: ty::BoundConstness::NotConst,
1120 polarity: ty::ImplPolarity::Positive,
1125 impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
1126 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1127 self.map_bound(|p| PredicateKind::Clause(Clause::Trait(p))).to_predicate(tcx)
1131 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1132 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1133 self.map_bound(|p| PredicateKind::Clause(Clause::RegionOutlives(p))).to_predicate(tcx)
1137 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1138 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1139 self.map_bound(|p| PredicateKind::Clause(Clause::TypeOutlives(p))).to_predicate(tcx)
1143 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1144 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1145 self.map_bound(|p| PredicateKind::Clause(Clause::Projection(p))).to_predicate(tcx)
1149 impl<'tcx> Predicate<'tcx> {
1150 pub fn to_opt_poly_trait_pred(self) -> Option<PolyTraitPredicate<'tcx>> {
1151 let predicate = self.kind();
1152 match predicate.skip_binder() {
1153 PredicateKind::Clause(Clause::Trait(t)) => Some(predicate.rebind(t)),
1154 PredicateKind::Clause(Clause::Projection(..))
1155 | PredicateKind::Subtype(..)
1156 | PredicateKind::Coerce(..)
1157 | PredicateKind::Clause(Clause::RegionOutlives(..))
1158 | PredicateKind::WellFormed(..)
1159 | PredicateKind::ObjectSafe(..)
1160 | PredicateKind::ClosureKind(..)
1161 | PredicateKind::Clause(Clause::TypeOutlives(..))
1162 | PredicateKind::ConstEvaluatable(..)
1163 | PredicateKind::ConstEquate(..)
1164 | PredicateKind::Ambiguous
1165 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1169 pub fn to_opt_poly_projection_pred(self) -> Option<PolyProjectionPredicate<'tcx>> {
1170 let predicate = self.kind();
1171 match predicate.skip_binder() {
1172 PredicateKind::Clause(Clause::Projection(t)) => Some(predicate.rebind(t)),
1173 PredicateKind::Clause(Clause::Trait(..))
1174 | PredicateKind::Subtype(..)
1175 | PredicateKind::Coerce(..)
1176 | PredicateKind::Clause(Clause::RegionOutlives(..))
1177 | PredicateKind::WellFormed(..)
1178 | PredicateKind::ObjectSafe(..)
1179 | PredicateKind::ClosureKind(..)
1180 | PredicateKind::Clause(Clause::TypeOutlives(..))
1181 | PredicateKind::ConstEvaluatable(..)
1182 | PredicateKind::ConstEquate(..)
1183 | PredicateKind::Ambiguous
1184 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1188 pub fn to_opt_type_outlives(self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1189 let predicate = self.kind();
1190 match predicate.skip_binder() {
1191 PredicateKind::Clause(Clause::TypeOutlives(data)) => Some(predicate.rebind(data)),
1192 PredicateKind::Clause(Clause::Trait(..))
1193 | PredicateKind::Clause(Clause::Projection(..))
1194 | PredicateKind::Subtype(..)
1195 | PredicateKind::Coerce(..)
1196 | PredicateKind::Clause(Clause::RegionOutlives(..))
1197 | PredicateKind::WellFormed(..)
1198 | PredicateKind::ObjectSafe(..)
1199 | PredicateKind::ClosureKind(..)
1200 | PredicateKind::ConstEvaluatable(..)
1201 | PredicateKind::ConstEquate(..)
1202 | PredicateKind::Ambiguous
1203 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1208 /// Represents the bounds declared on a particular set of type
1209 /// parameters. Should eventually be generalized into a flag list of
1210 /// where-clauses. You can obtain an `InstantiatedPredicates` list from a
1211 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1212 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1213 /// the `GenericPredicates` are expressed in terms of the bound type
1214 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1215 /// represented a set of bounds for some particular instantiation,
1216 /// meaning that the generic parameters have been substituted with
1220 /// ```ignore (illustrative)
1221 /// struct Foo<T, U: Bar<T>> { ... }
1223 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1224 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1225 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1226 /// [usize:Bar<isize>]]`.
1227 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
1228 pub struct InstantiatedPredicates<'tcx> {
1229 pub predicates: Vec<Predicate<'tcx>>,
1230 pub spans: Vec<Span>,
1233 impl<'tcx> InstantiatedPredicates<'tcx> {
1234 pub fn empty() -> InstantiatedPredicates<'tcx> {
1235 InstantiatedPredicates { predicates: vec![], spans: vec![] }
1238 pub fn is_empty(&self) -> bool {
1239 self.predicates.is_empty()
1242 pub fn iter(&self) -> <&Self as IntoIterator>::IntoIter {
1247 impl<'tcx> IntoIterator for InstantiatedPredicates<'tcx> {
1248 type Item = (Predicate<'tcx>, Span);
1250 type IntoIter = std::iter::Zip<std::vec::IntoIter<Predicate<'tcx>>, std::vec::IntoIter<Span>>;
1252 fn into_iter(self) -> Self::IntoIter {
1253 debug_assert_eq!(self.predicates.len(), self.spans.len());
1254 std::iter::zip(self.predicates, self.spans)
1258 impl<'a, 'tcx> IntoIterator for &'a InstantiatedPredicates<'tcx> {
1259 type Item = (Predicate<'tcx>, Span);
1261 type IntoIter = std::iter::Zip<
1262 std::iter::Copied<std::slice::Iter<'a, Predicate<'tcx>>>,
1263 std::iter::Copied<std::slice::Iter<'a, Span>>,
1266 fn into_iter(self) -> Self::IntoIter {
1267 debug_assert_eq!(self.predicates.len(), self.spans.len());
1268 std::iter::zip(self.predicates.iter().copied(), self.spans.iter().copied())
1272 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable, Lift)]
1273 #[derive(TypeFoldable, TypeVisitable)]
1274 pub struct OpaqueTypeKey<'tcx> {
1275 pub def_id: LocalDefId,
1276 pub substs: SubstsRef<'tcx>,
1279 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
1280 pub struct OpaqueHiddenType<'tcx> {
1281 /// The span of this particular definition of the opaque type. So
1284 /// ```ignore (incomplete snippet)
1285 /// type Foo = impl Baz;
1286 /// fn bar() -> Foo {
1287 /// // ^^^ This is the span we are looking for!
1291 /// In cases where the fn returns `(impl Trait, impl Trait)` or
1292 /// other such combinations, the result is currently
1293 /// over-approximated, but better than nothing.
1296 /// The type variable that represents the value of the opaque type
1297 /// that we require. In other words, after we compile this function,
1298 /// we will be created a constraint like:
1299 /// ```ignore (pseudo-rust)
1302 /// where `?C` is the value of this type variable. =) It may
1303 /// naturally refer to the type and lifetime parameters in scope
1304 /// in this function, though ultimately it should only reference
1305 /// those that are arguments to `Foo` in the constraint above. (In
1306 /// other words, `?C` should not include `'b`, even though it's a
1307 /// lifetime parameter on `foo`.)
1311 impl<'tcx> OpaqueHiddenType<'tcx> {
1312 pub fn report_mismatch(&self, other: &Self, tcx: TyCtxt<'tcx>) {
1313 // Found different concrete types for the opaque type.
1314 let sub_diag = if self.span == other.span {
1315 TypeMismatchReason::ConflictType { span: self.span }
1317 TypeMismatchReason::PreviousUse { span: self.span }
1319 tcx.sess.emit_err(OpaqueHiddenTypeMismatch {
1322 other_span: other.span,
1327 #[instrument(level = "debug", skip(tcx), ret)]
1328 pub fn remap_generic_params_to_declaration_params(
1330 opaque_type_key: OpaqueTypeKey<'tcx>,
1332 // typeck errors have subpar spans for opaque types, so delay error reporting until borrowck.
1333 ignore_errors: bool,
1335 let OpaqueTypeKey { def_id, substs } = opaque_type_key;
1337 // Use substs to build up a reverse map from regions to their
1338 // identity mappings. This is necessary because of `impl
1339 // Trait` lifetimes are computed by replacing existing
1340 // lifetimes with 'static and remapping only those used in the
1341 // `impl Trait` return type, resulting in the parameters
1343 let id_substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
1346 // This zip may have several times the same lifetime in `substs` paired with a different
1347 // lifetime from `id_substs`. Simply `collect`ing the iterator is the correct behaviour:
1348 // it will pick the last one, which is the one we introduced in the impl-trait desugaring.
1349 let map = substs.iter().zip(id_substs).collect();
1350 debug!("map = {:#?}", map);
1352 // Convert the type from the function into a type valid outside
1353 // the function, by replacing invalid regions with 'static,
1354 // after producing an error for each of them.
1355 self.fold_with(&mut opaque_types::ReverseMapper::new(tcx, map, self.span, ignore_errors))
1359 /// The "placeholder index" fully defines a placeholder region, type, or const. Placeholders are
1360 /// identified by both a universe, as well as a name residing within that universe. Distinct bound
1361 /// regions/types/consts within the same universe simply have an unknown relationship to one
1363 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
1364 #[derive(HashStable, TyEncodable, TyDecodable)]
1365 pub struct Placeholder<T> {
1366 pub universe: UniverseIndex,
1370 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
1372 pub type PlaceholderType = Placeholder<BoundVar>;
1374 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1375 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]
1376 pub struct BoundConst<'tcx> {
1381 pub type PlaceholderConst<'tcx> = Placeholder<BoundVar>;
1383 /// A `DefId` which, in case it is a const argument, is potentially bundled with
1384 /// the `DefId` of the generic parameter it instantiates.
1386 /// This is used to avoid calls to `type_of` for const arguments during typeck
1387 /// which cause cycle errors.
1392 /// fn foo<const N: usize>(&self) -> [u8; N] { [0; N] }
1393 /// // ^ const parameter
1397 /// fn foo<const M: u8>(&self) -> usize { 42 }
1398 /// // ^ const parameter
1403 /// let _b = a.foo::<{ 3 + 7 }>();
1404 /// // ^^^^^^^^^ const argument
1408 /// Let's look at the call `a.foo::<{ 3 + 7 }>()` here. We do not know
1409 /// which `foo` is used until we know the type of `a`.
1411 /// We only know the type of `a` once we are inside of `typeck(main)`.
1412 /// We also end up normalizing the type of `_b` during `typeck(main)` which
1413 /// requires us to evaluate the const argument.
1415 /// To evaluate that const argument we need to know its type,
1416 /// which we would get using `type_of(const_arg)`. This requires us to
1417 /// resolve `foo` as it can be either `usize` or `u8` in this example.
1418 /// However, resolving `foo` once again requires `typeck(main)` to get the type of `a`,
1419 /// which results in a cycle.
1421 /// In short we must not call `type_of(const_arg)` during `typeck(main)`.
1423 /// When first creating the `ty::Const` of the const argument inside of `typeck` we have
1424 /// already resolved `foo` so we know which const parameter this argument instantiates.
1425 /// This means that we also know the expected result of `type_of(const_arg)` even if we
1426 /// aren't allowed to call that query: it is equal to `type_of(const_param)` which is
1427 /// trivial to compute.
1429 /// If we now want to use that constant in a place which potentially needs its type
1430 /// we also pass the type of its `const_param`. This is the point of `WithOptConstParam`,
1431 /// except that instead of a `Ty` we bundle the `DefId` of the const parameter.
1432 /// Meaning that we need to use `type_of(const_param_did)` if `const_param_did` is `Some`
1433 /// to get the type of `did`.
1434 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift, TyEncodable, TyDecodable)]
1435 #[derive(PartialEq, Eq, PartialOrd, Ord)]
1436 #[derive(Hash, HashStable)]
1437 pub struct WithOptConstParam<T> {
1439 /// The `DefId` of the corresponding generic parameter in case `did` is
1440 /// a const argument.
1442 /// Note that even if `did` is a const argument, this may still be `None`.
1443 /// All queries taking `WithOptConstParam` start by calling `tcx.opt_const_param_of(def.did)`
1444 /// to potentially update `param_did` in the case it is `None`.
1445 pub const_param_did: Option<DefId>,
1448 impl<T> WithOptConstParam<T> {
1449 /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`.
1451 pub fn unknown(did: T) -> WithOptConstParam<T> {
1452 WithOptConstParam { did, const_param_did: None }
1456 impl WithOptConstParam<LocalDefId> {
1457 /// Returns `Some((did, param_did))` if `def_id` is a const argument,
1458 /// `None` otherwise.
1460 pub fn try_lookup(did: LocalDefId, tcx: TyCtxt<'_>) -> Option<(LocalDefId, DefId)> {
1461 tcx.opt_const_param_of(did).map(|param_did| (did, param_did))
1464 /// In case `self` is unknown but `self.did` is a const argument, this returns
1465 /// a `WithOptConstParam` with the correct `const_param_did`.
1467 pub fn try_upgrade(self, tcx: TyCtxt<'_>) -> Option<WithOptConstParam<LocalDefId>> {
1468 if self.const_param_did.is_none() {
1469 if let const_param_did @ Some(_) = tcx.opt_const_param_of(self.did) {
1470 return Some(WithOptConstParam { did: self.did, const_param_did });
1477 pub fn to_global(self) -> WithOptConstParam<DefId> {
1478 WithOptConstParam { did: self.did.to_def_id(), const_param_did: self.const_param_did }
1481 pub fn def_id_for_type_of(self) -> DefId {
1482 if let Some(did) = self.const_param_did { did } else { self.did.to_def_id() }
1486 impl WithOptConstParam<DefId> {
1487 pub fn as_local(self) -> Option<WithOptConstParam<LocalDefId>> {
1490 .map(|did| WithOptConstParam { did, const_param_did: self.const_param_did })
1493 pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)> {
1494 if let Some(param_did) = self.const_param_did {
1495 if let Some(did) = self.did.as_local() {
1496 return Some((did, param_did));
1503 pub fn is_local(self) -> bool {
1507 pub fn def_id_for_type_of(self) -> DefId {
1508 self.const_param_did.unwrap_or(self.did)
1512 /// When type checking, we use the `ParamEnv` to track
1513 /// details about the set of where-clauses that are in scope at this
1514 /// particular point.
1515 #[derive(Copy, Clone, Hash, PartialEq, Eq)]
1516 pub struct ParamEnv<'tcx> {
1517 /// This packs both caller bounds and the reveal enum into one pointer.
1519 /// Caller bounds are `Obligation`s that the caller must satisfy. This is
1520 /// basically the set of bounds on the in-scope type parameters, translated
1521 /// into `Obligation`s, and elaborated and normalized.
1523 /// Use the `caller_bounds()` method to access.
1525 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1526 /// want `Reveal::All`.
1528 /// Note: This is packed, use the reveal() method to access it.
1529 packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, ParamTag, true>,
1532 #[derive(Copy, Clone)]
1534 reveal: traits::Reveal,
1535 constness: hir::Constness,
1538 unsafe impl rustc_data_structures::tagged_ptr::Tag for ParamTag {
1539 const BITS: usize = 2;
1541 fn into_usize(self) -> usize {
1543 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst } => 0,
1544 Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst } => 1,
1545 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const } => 2,
1546 Self { reveal: traits::Reveal::All, constness: hir::Constness::Const } => 3,
1550 unsafe fn from_usize(ptr: usize) -> Self {
1552 0 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst },
1553 1 => Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst },
1554 2 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const },
1555 3 => Self { reveal: traits::Reveal::All, constness: hir::Constness::Const },
1556 _ => std::hint::unreachable_unchecked(),
1561 impl<'tcx> fmt::Debug for ParamEnv<'tcx> {
1562 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1563 f.debug_struct("ParamEnv")
1564 .field("caller_bounds", &self.caller_bounds())
1565 .field("reveal", &self.reveal())
1566 .field("constness", &self.constness())
1571 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx> {
1572 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1573 self.caller_bounds().hash_stable(hcx, hasher);
1574 self.reveal().hash_stable(hcx, hasher);
1575 self.constness().hash_stable(hcx, hasher);
1579 impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
1580 fn try_fold_with<F: ty::fold::FallibleTypeFolder<'tcx>>(
1583 ) -> Result<Self, F::Error> {
1585 self.caller_bounds().try_fold_with(folder)?,
1586 self.reveal().try_fold_with(folder)?,
1592 impl<'tcx> TypeVisitable<'tcx> for ParamEnv<'tcx> {
1593 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
1594 self.caller_bounds().visit_with(visitor)?;
1595 self.reveal().visit_with(visitor)
1599 impl<'tcx> ParamEnv<'tcx> {
1600 /// Construct a trait environment suitable for contexts where
1601 /// there are no where-clauses in scope. Hidden types (like `impl
1602 /// Trait`) are left hidden, so this is suitable for ordinary
1605 pub fn empty() -> Self {
1606 Self::new(List::empty(), Reveal::UserFacing, hir::Constness::NotConst)
1610 pub fn caller_bounds(self) -> &'tcx List<Predicate<'tcx>> {
1611 self.packed.pointer()
1615 pub fn reveal(self) -> traits::Reveal {
1616 self.packed.tag().reveal
1620 pub fn constness(self) -> hir::Constness {
1621 self.packed.tag().constness
1625 pub fn is_const(self) -> bool {
1626 self.packed.tag().constness == hir::Constness::Const
1629 /// Construct a trait environment with no where-clauses in scope
1630 /// where the values of all `impl Trait` and other hidden types
1631 /// are revealed. This is suitable for monomorphized, post-typeck
1632 /// environments like codegen or doing optimizations.
1634 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1635 /// or invoke `param_env.with_reveal_all()`.
1637 pub fn reveal_all() -> Self {
1638 Self::new(List::empty(), Reveal::All, hir::Constness::NotConst)
1641 /// Construct a trait environment with the given set of predicates.
1644 caller_bounds: &'tcx List<Predicate<'tcx>>,
1646 constness: hir::Constness,
1648 ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, ParamTag { reveal, constness }) }
1651 pub fn with_user_facing(mut self) -> Self {
1652 self.packed.set_tag(ParamTag { reveal: Reveal::UserFacing, ..self.packed.tag() });
1657 pub fn with_constness(mut self, constness: hir::Constness) -> Self {
1658 self.packed.set_tag(ParamTag { constness, ..self.packed.tag() });
1663 pub fn with_const(mut self) -> Self {
1664 self.packed.set_tag(ParamTag { constness: hir::Constness::Const, ..self.packed.tag() });
1669 pub fn without_const(mut self) -> Self {
1670 self.packed.set_tag(ParamTag { constness: hir::Constness::NotConst, ..self.packed.tag() });
1675 pub fn remap_constness_with(&mut self, mut constness: ty::BoundConstness) {
1676 *self = self.with_constness(constness.and(self.constness()))
1679 /// Returns a new parameter environment with the same clauses, but
1680 /// which "reveals" the true results of projections in all cases
1681 /// (even for associated types that are specializable). This is
1682 /// the desired behavior during codegen and certain other special
1683 /// contexts; normally though we want to use `Reveal::UserFacing`,
1684 /// which is the default.
1685 /// All opaque types in the caller_bounds of the `ParamEnv`
1686 /// will be normalized to their underlying types.
1687 /// See PR #65989 and issue #65918 for more details
1688 pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self {
1689 if self.packed.tag().reveal == traits::Reveal::All {
1694 tcx.reveal_opaque_types_in_bounds(self.caller_bounds()),
1700 /// Returns this same environment but with no caller bounds.
1702 pub fn without_caller_bounds(self) -> Self {
1703 Self::new(List::empty(), self.reveal(), self.constness())
1706 /// Creates a suitable environment in which to perform trait
1707 /// queries on the given value. When type-checking, this is simply
1708 /// the pair of the environment plus value. But when reveal is set to
1709 /// All, then if `value` does not reference any type parameters, we will
1710 /// pair it with the empty environment. This improves caching and is generally
1713 /// N.B., we preserve the environment when type-checking because it
1714 /// is possible for the user to have wacky where-clauses like
1715 /// `where Box<u32>: Copy`, which are clearly never
1716 /// satisfiable. We generally want to behave as if they were true,
1717 /// although the surrounding function is never reachable.
1718 pub fn and<T: TypeVisitable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1719 match self.reveal() {
1720 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1723 if value.is_global() {
1724 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1726 ParamEnvAnd { param_env: self, value }
1733 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
1734 // the constness of trait bounds is being propagated correctly.
1735 impl<'tcx> PolyTraitRef<'tcx> {
1737 pub fn with_constness(self, constness: BoundConstness) -> PolyTraitPredicate<'tcx> {
1738 self.map_bound(|trait_ref| ty::TraitPredicate {
1741 polarity: ty::ImplPolarity::Positive,
1746 pub fn without_const(self) -> PolyTraitPredicate<'tcx> {
1747 self.with_constness(BoundConstness::NotConst)
1751 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
1752 #[derive(HashStable, Lift)]
1753 pub struct ParamEnvAnd<'tcx, T> {
1754 pub param_env: ParamEnv<'tcx>,
1758 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1759 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1760 (self.param_env, self.value)
1764 pub fn without_const(mut self) -> Self {
1765 self.param_env = self.param_env.without_const();
1770 #[derive(Copy, Clone, Debug, HashStable, Encodable, Decodable)]
1771 pub struct Destructor {
1772 /// The `DefId` of the destructor method
1774 /// The constness of the destructor method
1775 pub constness: hir::Constness,
1779 #[derive(HashStable, TyEncodable, TyDecodable)]
1780 pub struct VariantFlags: u32 {
1781 const NO_VARIANT_FLAGS = 0;
1782 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1783 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1784 /// Indicates whether this variant was obtained as part of recovering from
1785 /// a syntactic error. May be incomplete or bogus.
1786 const IS_RECOVERED = 1 << 1;
1790 /// Definition of a variant -- a struct's fields or an enum variant.
1791 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
1792 pub struct VariantDef {
1793 /// `DefId` that identifies the variant itself.
1794 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1796 /// `DefId` that identifies the variant's constructor.
1797 /// If this variant is a struct variant, then this is `None`.
1798 pub ctor: Option<(CtorKind, DefId)>,
1799 /// Variant or struct name.
1801 /// Discriminant of this variant.
1802 pub discr: VariantDiscr,
1803 /// Fields of this variant.
1804 pub fields: Vec<FieldDef>,
1805 /// Flags of the variant (e.g. is field list non-exhaustive)?
1806 flags: VariantFlags,
1810 /// Creates a new `VariantDef`.
1812 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1813 /// represents an enum variant).
1815 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1816 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1818 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1819 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1820 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1821 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1822 /// built-in trait), and we do not want to load attributes twice.
1824 /// If someone speeds up attribute loading to not be a performance concern, they can
1825 /// remove this hack and use the constructor `DefId` everywhere.
1828 variant_did: Option<DefId>,
1829 ctor: Option<(CtorKind, DefId)>,
1830 discr: VariantDiscr,
1831 fields: Vec<FieldDef>,
1835 is_field_list_non_exhaustive: bool,
1838 "VariantDef::new(name = {:?}, variant_did = {:?}, ctor = {:?}, discr = {:?},
1839 fields = {:?}, adt_kind = {:?}, parent_did = {:?})",
1840 name, variant_did, ctor, discr, fields, adt_kind, parent_did,
1843 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1844 if is_field_list_non_exhaustive {
1845 flags |= VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1849 flags |= VariantFlags::IS_RECOVERED;
1852 VariantDef { def_id: variant_did.unwrap_or(parent_did), ctor, name, discr, fields, flags }
1855 /// Is this field list non-exhaustive?
1857 pub fn is_field_list_non_exhaustive(&self) -> bool {
1858 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1861 /// Was this variant obtained as part of recovering from a syntactic error?
1863 pub fn is_recovered(&self) -> bool {
1864 self.flags.intersects(VariantFlags::IS_RECOVERED)
1867 /// Computes the `Ident` of this variant by looking up the `Span`
1868 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
1869 Ident::new(self.name, tcx.def_ident_span(self.def_id).unwrap())
1873 pub fn ctor_kind(&self) -> Option<CtorKind> {
1874 self.ctor.map(|(kind, _)| kind)
1878 pub fn ctor_def_id(&self) -> Option<DefId> {
1879 self.ctor.map(|(_, def_id)| def_id)
1883 impl PartialEq for VariantDef {
1885 fn eq(&self, other: &Self) -> bool {
1886 // There should be only one `VariantDef` for each `def_id`, therefore
1887 // it is fine to implement `PartialEq` only based on `def_id`.
1889 // Below, we exhaustively destructure `self` and `other` so that if the
1890 // definition of `VariantDef` changes, a compile-error will be produced,
1891 // reminding us to revisit this assumption.
1893 let Self { def_id: lhs_def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = &self;
1894 let Self { def_id: rhs_def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = other;
1895 lhs_def_id == rhs_def_id
1899 impl Eq for VariantDef {}
1901 impl Hash for VariantDef {
1903 fn hash<H: Hasher>(&self, s: &mut H) {
1904 // There should be only one `VariantDef` for each `def_id`, therefore
1905 // it is fine to implement `Hash` only based on `def_id`.
1907 // Below, we exhaustively destructure `self` so that if the definition
1908 // of `VariantDef` changes, a compile-error will be produced, reminding
1909 // us to revisit this assumption.
1911 let Self { def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = &self;
1916 #[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
1917 pub enum VariantDiscr {
1918 /// Explicit value for this variant, i.e., `X = 123`.
1919 /// The `DefId` corresponds to the embedded constant.
1922 /// The previous variant's discriminant plus one.
1923 /// For efficiency reasons, the distance from the
1924 /// last `Explicit` discriminant is being stored,
1925 /// or `0` for the first variant, if it has none.
1929 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
1930 pub struct FieldDef {
1933 pub vis: Visibility<DefId>,
1936 impl PartialEq for FieldDef {
1938 fn eq(&self, other: &Self) -> bool {
1939 // There should be only one `FieldDef` for each `did`, therefore it is
1940 // fine to implement `PartialEq` only based on `did`.
1942 // Below, we exhaustively destructure `self` so that if the definition
1943 // of `FieldDef` changes, a compile-error will be produced, reminding
1944 // us to revisit this assumption.
1946 let Self { did: lhs_did, name: _, vis: _ } = &self;
1948 let Self { did: rhs_did, name: _, vis: _ } = other;
1954 impl Eq for FieldDef {}
1956 impl Hash for FieldDef {
1958 fn hash<H: Hasher>(&self, s: &mut H) {
1959 // There should be only one `FieldDef` for each `did`, therefore it is
1960 // fine to implement `Hash` only based on `did`.
1962 // Below, we exhaustively destructure `self` so that if the definition
1963 // of `FieldDef` changes, a compile-error will be produced, reminding
1964 // us to revisit this assumption.
1966 let Self { did, name: _, vis: _ } = &self;
1972 impl<'tcx> FieldDef {
1973 /// Returns the type of this field. The resulting type is not normalized. The `subst` is
1974 /// typically obtained via the second field of [`TyKind::Adt`].
1975 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
1976 tcx.bound_type_of(self.did).subst(tcx, subst)
1979 /// Computes the `Ident` of this variant by looking up the `Span`
1980 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
1981 Ident::new(self.name, tcx.def_ident_span(self.did).unwrap())
1985 pub type Attributes<'tcx> = impl Iterator<Item = &'tcx ast::Attribute>;
1986 #[derive(Debug, PartialEq, Eq)]
1987 pub enum ImplOverlapKind {
1988 /// These impls are always allowed to overlap.
1990 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
1993 /// These impls are allowed to overlap, but that raises
1994 /// an issue #33140 future-compatibility warning.
1996 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
1997 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
1999 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2000 /// that difference, making what reduces to the following set of impls:
2002 /// ```compile_fail,(E0119)
2004 /// impl Trait for dyn Send + Sync {}
2005 /// impl Trait for dyn Sync + Send {}
2008 /// Obviously, once we made these types be identical, that code causes a coherence
2009 /// error and a fairly big headache for us. However, luckily for us, the trait
2010 /// `Trait` used in this case is basically a marker trait, and therefore having
2011 /// overlapping impls for it is sound.
2013 /// To handle this, we basically regard the trait as a marker trait, with an additional
2014 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2015 /// it has the following restrictions:
2017 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2019 /// 2. The trait-ref of both impls must be equal.
2020 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2022 /// 4. Neither of the impls can have any where-clauses.
2024 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2028 impl<'tcx> TyCtxt<'tcx> {
2029 pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> {
2030 self.typeck(self.hir().body_owner_def_id(body))
2033 pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
2034 self.associated_items(id)
2035 .in_definition_order()
2036 .filter(move |item| item.kind == AssocKind::Fn && item.defaultness(self).has_value())
2039 pub fn repr_options_of_def(self, did: DefId) -> ReprOptions {
2040 let mut flags = ReprFlags::empty();
2041 let mut size = None;
2042 let mut max_align: Option<Align> = None;
2043 let mut min_pack: Option<Align> = None;
2045 // Generate a deterministically-derived seed from the item's path hash
2046 // to allow for cross-crate compilation to actually work
2047 let mut field_shuffle_seed = self.def_path_hash(did).0.to_smaller_hash();
2049 // If the user defined a custom seed for layout randomization, xor the item's
2050 // path hash with the user defined seed, this will allowing determinism while
2051 // still allowing users to further randomize layout generation for e.g. fuzzing
2052 if let Some(user_seed) = self.sess.opts.unstable_opts.layout_seed {
2053 field_shuffle_seed ^= user_seed;
2056 for attr in self.get_attrs(did, sym::repr) {
2057 for r in attr::parse_repr_attr(&self.sess, attr) {
2058 flags.insert(match r {
2059 attr::ReprC => ReprFlags::IS_C,
2060 attr::ReprPacked(pack) => {
2061 let pack = Align::from_bytes(pack as u64).unwrap();
2062 min_pack = Some(if let Some(min_pack) = min_pack {
2069 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2070 attr::ReprSimd => ReprFlags::IS_SIMD,
2071 attr::ReprInt(i) => {
2072 size = Some(match i {
2073 attr::IntType::SignedInt(x) => match x {
2074 ast::IntTy::Isize => IntegerType::Pointer(true),
2075 ast::IntTy::I8 => IntegerType::Fixed(Integer::I8, true),
2076 ast::IntTy::I16 => IntegerType::Fixed(Integer::I16, true),
2077 ast::IntTy::I32 => IntegerType::Fixed(Integer::I32, true),
2078 ast::IntTy::I64 => IntegerType::Fixed(Integer::I64, true),
2079 ast::IntTy::I128 => IntegerType::Fixed(Integer::I128, true),
2081 attr::IntType::UnsignedInt(x) => match x {
2082 ast::UintTy::Usize => IntegerType::Pointer(false),
2083 ast::UintTy::U8 => IntegerType::Fixed(Integer::I8, false),
2084 ast::UintTy::U16 => IntegerType::Fixed(Integer::I16, false),
2085 ast::UintTy::U32 => IntegerType::Fixed(Integer::I32, false),
2086 ast::UintTy::U64 => IntegerType::Fixed(Integer::I64, false),
2087 ast::UintTy::U128 => IntegerType::Fixed(Integer::I128, false),
2092 attr::ReprAlign(align) => {
2093 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2100 // If `-Z randomize-layout` was enabled for the type definition then we can
2101 // consider performing layout randomization
2102 if self.sess.opts.unstable_opts.randomize_layout {
2103 flags.insert(ReprFlags::RANDOMIZE_LAYOUT);
2106 // This is here instead of layout because the choice must make it into metadata.
2107 if !self.consider_optimizing(|| format!("Reorder fields of {:?}", self.def_path_str(did))) {
2108 flags.insert(ReprFlags::IS_LINEAR);
2111 ReprOptions { int: size, align: max_align, pack: min_pack, flags, field_shuffle_seed }
2114 /// Look up the name of a definition across crates. This does not look at HIR.
2115 pub fn opt_item_name(self, def_id: DefId) -> Option<Symbol> {
2116 if let Some(cnum) = def_id.as_crate_root() {
2117 Some(self.crate_name(cnum))
2119 let def_key = self.def_key(def_id);
2120 match def_key.disambiguated_data.data {
2121 // The name of a constructor is that of its parent.
2122 rustc_hir::definitions::DefPathData::Ctor => self
2123 .opt_item_name(DefId { krate: def_id.krate, index: def_key.parent.unwrap() }),
2124 // The name of opaque types only exists in HIR.
2125 rustc_hir::definitions::DefPathData::ImplTrait
2126 if let Some(def_id) = def_id.as_local() =>
2127 self.hir().opt_name(self.hir().local_def_id_to_hir_id(def_id)),
2128 _ => def_key.get_opt_name(),
2133 /// Look up the name of a definition across crates. This does not look at HIR.
2135 /// This method will ICE if the corresponding item does not have a name. In these cases, use
2136 /// [`opt_item_name`] instead.
2138 /// [`opt_item_name`]: Self::opt_item_name
2139 pub fn item_name(self, id: DefId) -> Symbol {
2140 self.opt_item_name(id).unwrap_or_else(|| {
2141 bug!("item_name: no name for {:?}", self.def_path(id));
2145 /// Look up the name and span of a definition.
2147 /// See [`item_name`][Self::item_name] for more information.
2148 pub fn opt_item_ident(self, def_id: DefId) -> Option<Ident> {
2149 let def = self.opt_item_name(def_id)?;
2152 .and_then(|id| self.def_ident_span(id))
2153 .unwrap_or(rustc_span::DUMMY_SP);
2154 Some(Ident::new(def, span))
2157 pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> {
2158 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2159 Some(self.associated_item(def_id))
2165 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2169 .position(|field| self.hygienic_eq(ident, field.ident(self), variant.def_id))
2172 /// Returns `true` if the impls are the same polarity and the trait either
2173 /// has no items or is annotated `#[marker]` and prevents item overrides.
2174 pub fn impls_are_allowed_to_overlap(
2178 ) -> Option<ImplOverlapKind> {
2179 // If either trait impl references an error, they're allowed to overlap,
2180 // as one of them essentially doesn't exist.
2181 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.subst_identity().references_error())
2183 .impl_trait_ref(def_id2)
2184 .map_or(false, |tr| tr.subst_identity().references_error())
2186 return Some(ImplOverlapKind::Permitted { marker: false });
2189 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2190 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
2191 // `#[rustc_reservation_impl]` impls don't overlap with anything
2193 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2196 return Some(ImplOverlapKind::Permitted { marker: false });
2198 (ImplPolarity::Positive, ImplPolarity::Negative)
2199 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
2200 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2202 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2207 (ImplPolarity::Positive, ImplPolarity::Positive)
2208 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2211 let is_marker_overlap = {
2212 let is_marker_impl = |def_id: DefId| -> bool {
2213 let trait_ref = self.impl_trait_ref(def_id);
2214 trait_ref.map_or(false, |tr| self.trait_def(tr.skip_binder().def_id).is_marker)
2216 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2219 if is_marker_overlap {
2221 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2224 Some(ImplOverlapKind::Permitted { marker: true })
2226 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2227 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2228 if self_ty1 == self_ty2 {
2230 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2233 return Some(ImplOverlapKind::Issue33140);
2236 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2237 def_id1, def_id2, self_ty1, self_ty2
2243 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
2248 /// Returns `ty::VariantDef` if `res` refers to a struct,
2249 /// or variant or their constructors, panics otherwise.
2250 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2252 Res::Def(DefKind::Variant, did) => {
2253 let enum_did = self.parent(did);
2254 self.adt_def(enum_did).variant_with_id(did)
2256 Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(),
2257 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2258 let variant_did = self.parent(variant_ctor_did);
2259 let enum_did = self.parent(variant_did);
2260 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2262 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2263 let struct_did = self.parent(ctor_did);
2264 self.adt_def(struct_did).non_enum_variant()
2266 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
2270 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2271 #[instrument(skip(self), level = "debug")]
2272 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
2274 ty::InstanceDef::Item(def) => {
2275 debug!("calling def_kind on def: {:?}", def);
2276 let def_kind = self.def_kind(def.did);
2277 debug!("returned from def_kind: {:?}", def_kind);
2280 | DefKind::Static(..)
2281 | DefKind::AssocConst
2283 | DefKind::AnonConst
2284 | DefKind::InlineConst => self.mir_for_ctfe_opt_const_arg(def),
2285 // If the caller wants `mir_for_ctfe` of a function they should not be using
2286 // `instance_mir`, so we'll assume const fn also wants the optimized version.
2288 assert_eq!(def.const_param_did, None);
2289 self.optimized_mir(def.did)
2293 ty::InstanceDef::VTableShim(..)
2294 | ty::InstanceDef::ReifyShim(..)
2295 | ty::InstanceDef::Intrinsic(..)
2296 | ty::InstanceDef::FnPtrShim(..)
2297 | ty::InstanceDef::Virtual(..)
2298 | ty::InstanceDef::ClosureOnceShim { .. }
2299 | ty::InstanceDef::DropGlue(..)
2300 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance),
2304 // FIXME(@lcnr): Remove this function.
2305 pub fn get_attrs_unchecked(self, did: DefId) -> &'tcx [ast::Attribute] {
2306 if let Some(did) = did.as_local() {
2307 self.hir().attrs(self.hir().local_def_id_to_hir_id(did))
2309 self.item_attrs(did)
2313 /// Gets all attributes with the given name.
2314 pub fn get_attrs(self, did: DefId, attr: Symbol) -> ty::Attributes<'tcx> {
2315 let filter_fn = move |a: &&ast::Attribute| a.has_name(attr);
2316 if let Some(did) = did.as_local() {
2317 self.hir().attrs(self.hir().local_def_id_to_hir_id(did)).iter().filter(filter_fn)
2318 } else if cfg!(debug_assertions) && rustc_feature::is_builtin_only_local(attr) {
2319 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2321 self.item_attrs(did).iter().filter(filter_fn)
2325 pub fn get_attr(self, did: DefId, attr: Symbol) -> Option<&'tcx ast::Attribute> {
2326 if cfg!(debug_assertions) && !rustc_feature::is_valid_for_get_attr(attr) {
2327 bug!("get_attr: unexpected called with DefId `{:?}`, attr `{:?}`", did, attr);
2329 self.get_attrs(did, attr).next()
2333 /// Determines whether an item is annotated with an attribute.
2334 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
2335 if cfg!(debug_assertions) && !did.is_local() && rustc_feature::is_builtin_only_local(attr) {
2336 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2338 self.get_attrs(did, attr).next().is_some()
2342 /// Returns `true` if this is an `auto trait`.
2343 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2344 self.trait_def(trait_def_id).has_auto_impl
2347 /// Returns `true` if this is a trait alias.
2348 pub fn trait_is_alias(self, trait_def_id: DefId) -> bool {
2349 self.def_kind(trait_def_id) == DefKind::TraitAlias
2352 pub fn trait_is_coinductive(self, trait_def_id: DefId) -> bool {
2353 self.trait_is_auto(trait_def_id) || self.lang_items().sized_trait() == Some(trait_def_id)
2356 /// Returns layout of a generator. Layout might be unavailable if the
2357 /// generator is tainted by errors.
2358 pub fn generator_layout(self, def_id: DefId) -> Option<&'tcx GeneratorLayout<'tcx>> {
2359 self.optimized_mir(def_id).generator_layout()
2362 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
2363 /// If it implements no trait, returns `None`.
2364 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2365 self.impl_trait_ref(def_id).map(|tr| tr.skip_binder().def_id)
2368 /// If the given `DefId` describes an item belonging to a trait,
2369 /// returns the `DefId` of the trait that the trait item belongs to;
2370 /// otherwise, returns `None`.
2371 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2372 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2373 let parent = self.parent(def_id);
2374 if let DefKind::Trait | DefKind::TraitAlias = self.def_kind(parent) {
2375 return Some(parent);
2381 /// If the given `DefId` describes a method belonging to an impl, returns the
2382 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
2383 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2384 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2385 let parent = self.parent(def_id);
2386 if let DefKind::Impl = self.def_kind(parent) {
2387 return Some(parent);
2393 /// If the given `DefId` belongs to a trait that was automatically derived, returns `true`.
2394 pub fn is_builtin_derive(self, def_id: DefId) -> bool {
2395 self.has_attr(def_id, sym::automatically_derived)
2398 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2399 /// with the name of the crate containing the impl.
2400 pub fn span_of_impl(self, impl_def_id: DefId) -> Result<Span, Symbol> {
2401 if let Some(impl_def_id) = impl_def_id.as_local() {
2402 Ok(self.def_span(impl_def_id))
2404 Err(self.crate_name(impl_def_id.krate))
2408 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
2409 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2410 /// definition's parent/scope to perform comparison.
2411 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2412 // We could use `Ident::eq` here, but we deliberately don't. The name
2413 // comparison fails frequently, and we want to avoid the expensive
2414 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
2415 use_name.name == def_name.name
2419 .hygienic_eq(def_name.span.ctxt(), self.expn_that_defined(def_parent_def_id))
2422 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
2423 ident.span.normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope));
2427 // FIXME(vincenzoapalzzo): move the HirId to a LocalDefId
2428 pub fn adjust_ident_and_get_scope(
2433 ) -> (Ident, DefId) {
2436 .normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope))
2437 .and_then(|actual_expansion| actual_expansion.expn_data().parent_module)
2438 .unwrap_or_else(|| self.parent_module(block).to_def_id());
2442 /// Returns `true` if the debuginfo for `span` should be collapsed to the outermost expansion
2443 /// site. Only applies when `Span` is the result of macro expansion.
2445 /// - If the `collapse_debuginfo` feature is enabled then debuginfo is not collapsed by default
2446 /// and only when a macro definition is annotated with `#[collapse_debuginfo]`.
2447 /// - If `collapse_debuginfo` is not enabled, then debuginfo is collapsed by default.
2449 /// When `-Zdebug-macros` is provided then debuginfo will never be collapsed.
2450 pub fn should_collapse_debuginfo(self, span: Span) -> bool {
2451 !self.sess.opts.unstable_opts.debug_macros
2452 && if self.features().collapse_debuginfo {
2453 span.in_macro_expansion_with_collapse_debuginfo()
2455 // Inlined spans should not be collapsed as that leads to all of the
2456 // inlined code being attributed to the inline callsite.
2457 span.from_expansion() && !span.is_inlined()
2461 pub fn is_object_safe(self, key: DefId) -> bool {
2462 self.object_safety_violations(key).is_empty()
2466 pub fn is_const_fn_raw(self, def_id: DefId) -> bool {
2468 self.def_kind(def_id),
2469 DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(..) | DefKind::Closure
2470 ) && self.constness(def_id) == hir::Constness::Const
2474 pub fn is_const_default_method(self, def_id: DefId) -> bool {
2475 matches!(self.trait_of_item(def_id), Some(trait_id) if self.has_attr(trait_id, sym::const_trait))
2478 pub fn impl_trait_in_trait_parent(self, mut def_id: DefId) -> DefId {
2479 while let def_kind = self.def_kind(def_id) && def_kind != DefKind::AssocFn {
2480 debug_assert_eq!(def_kind, DefKind::ImplTraitPlaceholder);
2481 def_id = self.parent(def_id);
2487 /// Yields the parent function's `LocalDefId` if `def_id` is an `impl Trait` definition.
2488 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<LocalDefId> {
2489 let def_id = def_id.as_local()?;
2490 if let Node::Item(item) = tcx.hir().get_by_def_id(def_id) {
2491 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
2492 return match opaque_ty.origin {
2493 hir::OpaqueTyOrigin::FnReturn(parent) | hir::OpaqueTyOrigin::AsyncFn(parent) => {
2496 hir::OpaqueTyOrigin::TyAlias => None,
2503 pub fn int_ty(ity: ast::IntTy) -> IntTy {
2505 ast::IntTy::Isize => IntTy::Isize,
2506 ast::IntTy::I8 => IntTy::I8,
2507 ast::IntTy::I16 => IntTy::I16,
2508 ast::IntTy::I32 => IntTy::I32,
2509 ast::IntTy::I64 => IntTy::I64,
2510 ast::IntTy::I128 => IntTy::I128,
2514 pub fn uint_ty(uty: ast::UintTy) -> UintTy {
2516 ast::UintTy::Usize => UintTy::Usize,
2517 ast::UintTy::U8 => UintTy::U8,
2518 ast::UintTy::U16 => UintTy::U16,
2519 ast::UintTy::U32 => UintTy::U32,
2520 ast::UintTy::U64 => UintTy::U64,
2521 ast::UintTy::U128 => UintTy::U128,
2525 pub fn float_ty(fty: ast::FloatTy) -> FloatTy {
2527 ast::FloatTy::F32 => FloatTy::F32,
2528 ast::FloatTy::F64 => FloatTy::F64,
2532 pub fn ast_int_ty(ity: IntTy) -> ast::IntTy {
2534 IntTy::Isize => ast::IntTy::Isize,
2535 IntTy::I8 => ast::IntTy::I8,
2536 IntTy::I16 => ast::IntTy::I16,
2537 IntTy::I32 => ast::IntTy::I32,
2538 IntTy::I64 => ast::IntTy::I64,
2539 IntTy::I128 => ast::IntTy::I128,
2543 pub fn ast_uint_ty(uty: UintTy) -> ast::UintTy {
2545 UintTy::Usize => ast::UintTy::Usize,
2546 UintTy::U8 => ast::UintTy::U8,
2547 UintTy::U16 => ast::UintTy::U16,
2548 UintTy::U32 => ast::UintTy::U32,
2549 UintTy::U64 => ast::UintTy::U64,
2550 UintTy::U128 => ast::UintTy::U128,
2554 pub fn provide(providers: &mut ty::query::Providers) {
2555 closure::provide(providers);
2556 context::provide(providers);
2557 erase_regions::provide(providers);
2558 inhabitedness::provide(providers);
2559 util::provide(providers);
2560 print::provide(providers);
2561 super::util::bug::provide(providers);
2562 super::middle::provide(providers);
2563 *providers = ty::query::Providers {
2564 trait_impls_of: trait_def::trait_impls_of_provider,
2565 incoherent_impls: trait_def::incoherent_impls_provider,
2566 const_param_default: consts::const_param_default,
2567 vtable_allocation: vtable::vtable_allocation_provider,
2572 /// A map for the local crate mapping each type to a vector of its
2573 /// inherent impls. This is not meant to be used outside of coherence;
2574 /// rather, you should request the vector for a specific type via
2575 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2576 /// (constructing this map requires touching the entire crate).
2577 #[derive(Clone, Debug, Default, HashStable)]
2578 pub struct CrateInherentImpls {
2579 pub inherent_impls: LocalDefIdMap<Vec<DefId>>,
2580 pub incoherent_impls: FxHashMap<SimplifiedType, Vec<LocalDefId>>,
2583 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]
2584 pub struct SymbolName<'tcx> {
2585 /// `&str` gives a consistent ordering, which ensures reproducible builds.
2586 pub name: &'tcx str,
2589 impl<'tcx> SymbolName<'tcx> {
2590 pub fn new(tcx: TyCtxt<'tcx>, name: &str) -> SymbolName<'tcx> {
2592 name: unsafe { str::from_utf8_unchecked(tcx.arena.alloc_slice(name.as_bytes())) },
2597 impl<'tcx> fmt::Display for SymbolName<'tcx> {
2598 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2599 fmt::Display::fmt(&self.name, fmt)
2603 impl<'tcx> fmt::Debug for SymbolName<'tcx> {
2604 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2605 fmt::Display::fmt(&self.name, fmt)
2609 #[derive(Debug, Default, Copy, Clone)]
2610 pub struct InferVarInfo {
2611 /// This is true if we identified that this Ty (`?T`) is found in a `?T: Foo`
2612 /// obligation, where:
2614 /// * `Foo` is not `Sized`
2615 /// * `(): Foo` may be satisfied
2616 pub self_in_trait: bool,
2617 /// This is true if we identified that this Ty (`?T`) is found in a `<_ as
2618 /// _>::AssocType = ?T`
2622 /// The constituent parts of a type level constant of kind ADT or array.
2623 #[derive(Copy, Clone, Debug, HashStable)]
2624 pub struct DestructuredConst<'tcx> {
2625 pub variant: Option<VariantIdx>,
2626 pub fields: &'tcx [ty::Const<'tcx>],
2629 // Some types are used a lot. Make sure they don't unintentionally get bigger.
2630 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2633 use rustc_data_structures::static_assert_size;
2634 // tidy-alphabetical-start
2635 static_assert_size!(PredicateKind<'_>, 32);
2636 static_assert_size!(WithCachedTypeInfo<TyKind<'_>>, 56);
2637 // tidy-alphabetical-end