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::fingerprint::Fingerprint;
35 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
36 use rustc_data_structures::intern::Interned;
37 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
38 use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
40 use rustc_hir::def::{CtorKind, CtorOf, DefKind, LifetimeRes, Res};
41 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LocalDefIdMap};
43 use rustc_index::vec::IndexVec;
44 use rustc_macros::HashStable;
45 use rustc_query_system::ich::StableHashingContext;
46 use rustc_serialize::{Decodable, Encodable};
47 use rustc_session::cstore::Untracked;
48 use rustc_span::hygiene::MacroKind;
49 use rustc_span::symbol::{kw, sym, Ident, Symbol};
50 use rustc_span::{ExpnId, Span};
51 use rustc_target::abi::{Align, Integer, IntegerType, VariantIdx};
52 pub use rustc_target::abi::{ReprFlags, ReprOptions};
53 use rustc_type_ir::WithCachedTypeInfo;
58 use std::hash::{Hash, Hasher};
59 use std::marker::PhantomData;
61 use std::num::NonZeroUsize;
62 use std::ops::ControlFlow;
65 pub use crate::ty::diagnostics::*;
66 pub use rustc_type_ir::AliasKind::*;
67 pub use rustc_type_ir::DynKind::*;
68 pub use rustc_type_ir::InferTy::*;
69 pub use rustc_type_ir::RegionKind::*;
70 pub use rustc_type_ir::TyKind::*;
71 pub use rustc_type_ir::*;
73 pub use self::binding::BindingMode;
74 pub use self::binding::BindingMode::*;
75 pub use self::closure::{
76 is_ancestor_or_same_capture, place_to_string_for_capture, BorrowKind, CaptureInfo,
77 CapturedPlace, ClosureKind, MinCaptureInformationMap, MinCaptureList,
78 RootVariableMinCaptureList, UpvarCapture, UpvarCaptureMap, UpvarId, UpvarListMap, UpvarPath,
81 pub use self::consts::{
82 Const, ConstData, ConstInt, ConstKind, Expr, InferConst, ScalarInt, UnevaluatedConst, ValTree,
84 pub use self::context::{
85 tls, CtxtInterners, DeducedParamAttrs, FreeRegionInfo, GlobalCtxt, Lift, OnDiskCache, TyCtxt,
88 pub use self::instance::{Instance, InstanceDef, ShortInstance, UnusedGenericParams};
89 pub use self::list::List;
90 pub use self::parameterized::ParameterizedOverTcx;
91 pub use self::rvalue_scopes::RvalueScopes;
92 pub use self::sty::BoundRegionKind::*;
94 AliasTy, Article, Binder, BoundRegion, BoundRegionKind, BoundTy, BoundTyKind, BoundVar,
95 BoundVariableKind, CanonicalPolyFnSig, ClosureSubsts, ClosureSubstsParts, ConstVid,
96 EarlyBoundRegion, ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FnSig,
97 FreeRegion, GenSig, GeneratorSubsts, GeneratorSubstsParts, InlineConstSubsts,
98 InlineConstSubstsParts, ParamConst, ParamTy, PolyExistentialPredicate,
99 PolyExistentialProjection, PolyExistentialTraitRef, PolyFnSig, PolyGenSig, PolyTraitRef,
100 Region, RegionKind, RegionVid, TraitRef, TyKind, TypeAndMut, UpvarSubsts, VarianceDiagInfo,
102 pub use self::trait_def::TraitDef;
103 pub use self::typeck_results::{
104 CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
105 GeneratorDiagnosticData, GeneratorInteriorTypeCause, TypeckResults, UserType,
106 UserTypeAnnotationIndex,
110 pub mod abstract_const;
119 pub mod inhabitedness;
121 pub mod normalize_erasing_regions;
146 mod structural_impls;
152 pub type RegisteredTools = FxHashSet<Ident>;
154 pub struct ResolverOutputs {
155 pub global_ctxt: ResolverGlobalCtxt,
156 pub ast_lowering: ResolverAstLowering,
157 pub untracked: Untracked,
161 pub struct ResolverGlobalCtxt {
162 pub visibilities: FxHashMap<LocalDefId, Visibility>,
163 /// This field is used to decide whether we should make `PRIVATE_IN_PUBLIC` a hard error.
164 pub has_pub_restricted: bool,
165 /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
166 pub expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
167 pub effective_visibilities: EffectiveVisibilities,
168 pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
169 pub maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
170 pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
171 pub reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
172 pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
173 /// Extern prelude entries. The value is `true` if the entry was introduced
174 /// via `extern crate` item and not `--extern` option or compiler built-in.
175 pub extern_prelude: FxHashMap<Symbol, bool>,
176 pub main_def: Option<MainDefinition>,
177 pub trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
178 /// A list of proc macro LocalDefIds, written out in the order in which
179 /// they are declared in the static array generated by proc_macro_harness.
180 pub proc_macros: Vec<LocalDefId>,
181 /// Mapping from ident span to path span for paths that don't exist as written, but that
182 /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
183 pub confused_type_with_std_module: FxHashMap<Span, Span>,
184 pub registered_tools: RegisteredTools,
187 /// Resolutions that should only be used for lowering.
188 /// This struct is meant to be consumed by lowering.
190 pub struct ResolverAstLowering {
191 pub legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
193 /// Resolutions for nodes that have a single resolution.
194 pub partial_res_map: NodeMap<hir::def::PartialRes>,
195 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
196 pub import_res_map: NodeMap<hir::def::PerNS<Option<Res<ast::NodeId>>>>,
197 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
198 pub label_res_map: NodeMap<ast::NodeId>,
199 /// Resolutions for lifetimes.
200 pub lifetimes_res_map: NodeMap<LifetimeRes>,
201 /// Lifetime parameters that lowering will have to introduce.
202 pub extra_lifetime_params_map: NodeMap<Vec<(Ident, ast::NodeId, LifetimeRes)>>,
204 pub next_node_id: ast::NodeId,
206 pub node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
207 pub def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
209 pub trait_map: NodeMap<Vec<hir::TraitCandidate>>,
210 /// A small map keeping true kinds of built-in macros that appear to be fn-like on
211 /// the surface (`macro` items in libcore), but are actually attributes or derives.
212 pub builtin_macro_kinds: FxHashMap<LocalDefId, MacroKind>,
213 /// List functions and methods for which lifetime elision was successful.
214 pub lifetime_elision_allowed: FxHashSet<ast::NodeId>,
217 #[derive(Clone, Copy, Debug)]
218 pub struct MainDefinition {
219 pub res: Res<ast::NodeId>,
224 impl MainDefinition {
225 pub fn opt_fn_def_id(self) -> Option<DefId> {
226 if let Res::Def(DefKind::Fn, def_id) = self.res { Some(def_id) } else { None }
230 /// The "header" of an impl is everything outside the body: a Self type, a trait
231 /// ref (in the case of a trait impl), and a set of predicates (from the
232 /// bounds / where-clauses).
233 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
234 pub struct ImplHeader<'tcx> {
235 pub impl_def_id: DefId,
236 pub self_ty: Ty<'tcx>,
237 pub trait_ref: Option<TraitRef<'tcx>>,
238 pub predicates: Vec<Predicate<'tcx>>,
241 #[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable)]
242 pub enum ImplSubject<'tcx> {
243 Trait(TraitRef<'tcx>),
247 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable, Debug)]
248 #[derive(TypeFoldable, TypeVisitable)]
249 pub enum ImplPolarity {
250 /// `impl Trait for Type`
252 /// `impl !Trait for Type`
254 /// `#[rustc_reservation_impl] impl Trait for Type`
256 /// This is a "stability hack", not a real Rust feature.
257 /// See #64631 for details.
262 /// Flips polarity by turning `Positive` into `Negative` and `Negative` into `Positive`.
263 pub fn flip(&self) -> Option<ImplPolarity> {
265 ImplPolarity::Positive => Some(ImplPolarity::Negative),
266 ImplPolarity::Negative => Some(ImplPolarity::Positive),
267 ImplPolarity::Reservation => None,
272 impl fmt::Display for ImplPolarity {
273 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
275 Self::Positive => f.write_str("positive"),
276 Self::Negative => f.write_str("negative"),
277 Self::Reservation => f.write_str("reservation"),
282 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, Encodable, Decodable, HashStable)]
283 pub enum Visibility<Id = LocalDefId> {
284 /// Visible everywhere (including in other crates).
286 /// Visible only in the given crate-local module.
290 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
291 pub enum BoundConstness {
294 /// `T: ~const Trait`
296 /// Requires resolving to const only when we are in a const context.
300 impl BoundConstness {
301 /// Reduce `self` and `constness` to two possible combined states instead of four.
302 pub fn and(&mut self, constness: hir::Constness) -> hir::Constness {
303 match (constness, self) {
304 (hir::Constness::Const, BoundConstness::ConstIfConst) => hir::Constness::Const,
306 *this = BoundConstness::NotConst;
307 hir::Constness::NotConst
313 impl fmt::Display for BoundConstness {
314 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
316 Self::NotConst => f.write_str("normal"),
317 Self::ConstIfConst => f.write_str("`~const`"),
322 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, TyEncodable, TyDecodable, HashStable)]
323 #[derive(TypeFoldable, TypeVisitable)]
324 pub struct ClosureSizeProfileData<'tcx> {
325 /// Tuple containing the types of closure captures before the feature `capture_disjoint_fields`
326 pub before_feature_tys: Ty<'tcx>,
327 /// Tuple containing the types of closure captures after the feature `capture_disjoint_fields`
328 pub after_feature_tys: Ty<'tcx>,
331 pub trait DefIdTree: Copy {
332 fn opt_parent(self, id: DefId) -> Option<DefId>;
336 fn parent(self, id: DefId) -> DefId {
337 match self.opt_parent(id) {
339 // not `unwrap_or_else` to avoid breaking caller tracking
340 None => bug!("{id:?} doesn't have a parent"),
346 fn opt_local_parent(self, id: LocalDefId) -> Option<LocalDefId> {
347 self.opt_parent(id.to_def_id()).map(DefId::expect_local)
352 fn local_parent(self, id: LocalDefId) -> LocalDefId {
353 self.parent(id.to_def_id()).expect_local()
356 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
357 if descendant.krate != ancestor.krate {
361 while descendant != ancestor {
362 match self.opt_parent(descendant) {
363 Some(parent) => descendant = parent,
364 None => return false,
371 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
373 fn opt_parent(self, id: DefId) -> Option<DefId> {
374 self.def_key(id).parent.map(|index| DefId { index, ..id })
378 impl<Id> Visibility<Id> {
379 pub fn is_public(self) -> bool {
380 matches!(self, Visibility::Public)
383 pub fn map_id<OutId>(self, f: impl FnOnce(Id) -> OutId) -> Visibility<OutId> {
385 Visibility::Public => Visibility::Public,
386 Visibility::Restricted(id) => Visibility::Restricted(f(id)),
391 impl<Id: Into<DefId>> Visibility<Id> {
392 pub fn to_def_id(self) -> Visibility<DefId> {
393 self.map_id(Into::into)
396 /// Returns `true` if an item with this visibility is accessible from the given module.
397 pub fn is_accessible_from(self, module: impl Into<DefId>, tree: impl DefIdTree) -> bool {
399 // Public items are visible everywhere.
400 Visibility::Public => true,
401 Visibility::Restricted(id) => tree.is_descendant_of(module.into(), id.into()),
405 /// Returns `true` if this visibility is at least as accessible as the given visibility
406 pub fn is_at_least(self, vis: Visibility<impl Into<DefId>>, tree: impl DefIdTree) -> bool {
408 Visibility::Public => self.is_public(),
409 Visibility::Restricted(id) => self.is_accessible_from(id, tree),
414 impl Visibility<DefId> {
415 pub fn expect_local(self) -> Visibility {
416 self.map_id(|id| id.expect_local())
419 /// Returns `true` if this item is visible anywhere in the local crate.
420 pub fn is_visible_locally(self) -> bool {
422 Visibility::Public => true,
423 Visibility::Restricted(def_id) => def_id.is_local(),
428 /// The crate variances map is computed during typeck and contains the
429 /// variance of every item in the local crate. You should not use it
430 /// directly, because to do so will make your pass dependent on the
431 /// HIR of every item in the local crate. Instead, use
432 /// `tcx.variances_of()` to get the variance for a *particular*
434 #[derive(HashStable, Debug)]
435 pub struct CrateVariancesMap<'tcx> {
436 /// For each item with generics, maps to a vector of the variance
437 /// of its generics. If an item has no generics, it will have no
439 pub variances: DefIdMap<&'tcx [ty::Variance]>,
442 // Contains information needed to resolve types and (in the future) look up
443 // the types of AST nodes.
444 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
445 pub struct CReaderCacheKey {
446 pub cnum: Option<CrateNum>,
450 /// Use this rather than `TyKind`, whenever possible.
451 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)]
452 #[rustc_diagnostic_item = "Ty"]
453 #[rustc_pass_by_value]
454 pub struct Ty<'tcx>(Interned<'tcx, WithCachedTypeInfo<TyKind<'tcx>>>);
456 impl<'tcx> TyCtxt<'tcx> {
457 /// A "bool" type used in rustc_mir_transform unit tests when we
458 /// have not spun up a TyCtxt.
459 pub const BOOL_TY_FOR_UNIT_TESTING: Ty<'tcx> =
460 Ty(Interned::new_unchecked(&WithCachedTypeInfo {
462 stable_hash: Fingerprint::ZERO,
463 flags: TypeFlags::empty(),
464 outer_exclusive_binder: DebruijnIndex::from_usize(0),
468 impl ty::EarlyBoundRegion {
469 /// Does this early bound region have a name? Early bound regions normally
470 /// always have names except when using anonymous lifetimes (`'_`).
471 pub fn has_name(&self) -> bool {
472 self.name != kw::UnderscoreLifetime && self.name != kw::Empty
476 /// Use this rather than `PredicateKind`, whenever possible.
477 #[derive(Clone, Copy, PartialEq, Eq, Hash, HashStable)]
478 #[rustc_pass_by_value]
479 pub struct Predicate<'tcx>(
480 Interned<'tcx, WithCachedTypeInfo<ty::Binder<'tcx, PredicateKind<'tcx>>>>,
483 impl<'tcx> Predicate<'tcx> {
484 /// Gets the inner `Binder<'tcx, PredicateKind<'tcx>>`.
486 pub fn kind(self) -> Binder<'tcx, PredicateKind<'tcx>> {
491 pub fn flags(self) -> TypeFlags {
496 pub fn outer_exclusive_binder(self) -> DebruijnIndex {
497 self.0.outer_exclusive_binder
500 /// Flips the polarity of a Predicate.
502 /// Given `T: Trait` predicate it returns `T: !Trait` and given `T: !Trait` returns `T: Trait`.
503 pub fn flip_polarity(self, tcx: TyCtxt<'tcx>) -> Option<Predicate<'tcx>> {
506 .map_bound(|kind| match kind {
507 PredicateKind::Clause(Clause::Trait(TraitPredicate {
511 })) => Some(PredicateKind::Clause(Clause::Trait(TraitPredicate {
514 polarity: polarity.flip()?,
521 Some(tcx.mk_predicate(kind))
524 pub fn without_const(mut self, tcx: TyCtxt<'tcx>) -> Self {
525 if let PredicateKind::Clause(Clause::Trait(TraitPredicate { trait_ref, constness, polarity })) = self.kind().skip_binder()
526 && constness != BoundConstness::NotConst
528 self = tcx.mk_predicate(self.kind().rebind(PredicateKind::Clause(Clause::Trait(TraitPredicate {
530 constness: BoundConstness::NotConst,
537 #[instrument(level = "debug", skip(tcx), ret)]
538 pub fn is_coinductive(self, tcx: TyCtxt<'tcx>) -> bool {
539 match self.kind().skip_binder() {
540 ty::PredicateKind::Clause(ty::Clause::Trait(data)) => {
541 tcx.trait_is_coinductive(data.def_id())
543 ty::PredicateKind::WellFormed(_) => true,
548 /// Whether this projection can be soundly normalized.
550 /// Wf predicates must not be normalized, as normalization
551 /// can remove required bounds which would cause us to
552 /// unsoundly accept some programs. See #91068.
554 pub fn allow_normalization(self) -> bool {
555 match self.kind().skip_binder() {
556 PredicateKind::WellFormed(_) => false,
557 PredicateKind::Clause(Clause::Trait(_))
558 | PredicateKind::Clause(Clause::RegionOutlives(_))
559 | PredicateKind::Clause(Clause::TypeOutlives(_))
560 | PredicateKind::Clause(Clause::Projection(_))
561 | PredicateKind::ObjectSafe(_)
562 | PredicateKind::ClosureKind(_, _, _)
563 | PredicateKind::Subtype(_)
564 | PredicateKind::Coerce(_)
565 | PredicateKind::ConstEvaluatable(_)
566 | PredicateKind::ConstEquate(_, _)
567 | PredicateKind::Ambiguous
568 | PredicateKind::TypeWellFormedFromEnv(_) => true,
573 impl rustc_errors::IntoDiagnosticArg for Predicate<'_> {
574 fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
575 rustc_errors::DiagnosticArgValue::Str(std::borrow::Cow::Owned(self.to_string()))
579 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
580 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
581 /// A clause is something that can appear in where bounds or be inferred
582 /// by implied bounds.
583 pub enum Clause<'tcx> {
584 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
585 /// the `Self` type of the trait reference and `A`, `B`, and `C`
586 /// would be the type parameters.
587 Trait(TraitPredicate<'tcx>),
590 RegionOutlives(RegionOutlivesPredicate<'tcx>),
593 TypeOutlives(TypeOutlivesPredicate<'tcx>),
595 /// `where <T as TraitRef>::Name == X`, approximately.
596 /// See the `ProjectionPredicate` struct for details.
597 Projection(ProjectionPredicate<'tcx>),
600 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
601 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
602 pub enum PredicateKind<'tcx> {
604 Clause(Clause<'tcx>),
606 /// No syntax: `T` well-formed.
607 WellFormed(GenericArg<'tcx>),
609 /// Trait must be object-safe.
612 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
613 /// for some substitutions `...` and `T` being a closure type.
614 /// Satisfied (or refuted) once we know the closure's kind.
615 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
619 /// This obligation is created most often when we have two
620 /// unresolved type variables and hence don't have enough
621 /// information to process the subtyping obligation yet.
622 Subtype(SubtypePredicate<'tcx>),
624 /// `T1` coerced to `T2`
626 /// Like a subtyping obligation, this is created most often
627 /// when we have two unresolved type variables and hence
628 /// don't have enough information to process the coercion
629 /// obligation yet. At the moment, we actually process coercions
630 /// very much like subtyping and don't handle the full coercion
632 Coerce(CoercePredicate<'tcx>),
634 /// Constant initializer must evaluate successfully.
635 ConstEvaluatable(ty::Const<'tcx>),
637 /// Constants must be equal. The first component is the const that is expected.
638 ConstEquate(Const<'tcx>, Const<'tcx>),
640 /// Represents a type found in the environment that we can use for implied bounds.
642 /// Only used for Chalk.
643 TypeWellFormedFromEnv(Ty<'tcx>),
645 /// A marker predicate that is always ambiguous.
646 /// Used for coherence to mark opaque types as possibly equal to each other but ambiguous.
650 /// The crate outlives map is computed during typeck and contains the
651 /// outlives of every item in the local crate. You should not use it
652 /// directly, because to do so will make your pass dependent on the
653 /// HIR of every item in the local crate. Instead, use
654 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
656 #[derive(HashStable, Debug)]
657 pub struct CratePredicatesMap<'tcx> {
658 /// For each struct with outlive bounds, maps to a vector of the
659 /// predicate of its outlive bounds. If an item has no outlives
660 /// bounds, it will have no entry.
661 pub predicates: FxHashMap<DefId, &'tcx [(Clause<'tcx>, Span)]>,
664 impl<'tcx> Predicate<'tcx> {
665 /// Performs a substitution suitable for going from a
666 /// poly-trait-ref to supertraits that must hold if that
667 /// poly-trait-ref holds. This is slightly different from a normal
668 /// substitution in terms of what happens with bound regions. See
669 /// lengthy comment below for details.
670 pub fn subst_supertrait(
673 trait_ref: &ty::PolyTraitRef<'tcx>,
674 ) -> Predicate<'tcx> {
675 // The interaction between HRTB and supertraits is not entirely
676 // obvious. Let me walk you (and myself) through an example.
678 // Let's start with an easy case. Consider two traits:
680 // trait Foo<'a>: Bar<'a,'a> { }
681 // trait Bar<'b,'c> { }
683 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
684 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
685 // knew that `Foo<'x>` (for any 'x) then we also know that
686 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
687 // normal substitution.
689 // In terms of why this is sound, the idea is that whenever there
690 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
691 // holds. So if there is an impl of `T:Foo<'a>` that applies to
692 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
695 // Another example to be careful of is this:
697 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
698 // trait Bar1<'b,'c> { }
700 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
701 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
702 // reason is similar to the previous example: any impl of
703 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
704 // basically we would want to collapse the bound lifetimes from
705 // the input (`trait_ref`) and the supertraits.
707 // To achieve this in practice is fairly straightforward. Let's
708 // consider the more complicated scenario:
710 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
711 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
712 // where both `'x` and `'b` would have a DB index of 1.
713 // The substitution from the input trait-ref is therefore going to be
714 // `'a => 'x` (where `'x` has a DB index of 1).
715 // - The supertrait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
716 // early-bound parameter and `'b' is a late-bound parameter with a
718 // - If we replace `'a` with `'x` from the input, it too will have
719 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
720 // just as we wanted.
722 // There is only one catch. If we just apply the substitution `'a
723 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
724 // adjust the DB index because we substituting into a binder (it
725 // tries to be so smart...) resulting in `for<'x> for<'b>
726 // Bar1<'x,'b>` (we have no syntax for this, so use your
727 // imagination). Basically the 'x will have DB index of 2 and 'b
728 // will have DB index of 1. Not quite what we want. So we apply
729 // the substitution to the *contents* of the trait reference,
730 // rather than the trait reference itself (put another way, the
731 // substitution code expects equal binding levels in the values
732 // from the substitution and the value being substituted into, and
733 // this trick achieves that).
735 // Working through the second example:
736 // trait_ref: for<'x> T: Foo1<'^0.0>; substs: [T, '^0.0]
737 // predicate: for<'b> Self: Bar1<'a, '^0.0>; substs: [Self, 'a, '^0.0]
738 // We want to end up with:
739 // for<'x, 'b> T: Bar1<'^0.0, '^0.1>
741 // 1) We must shift all bound vars in predicate by the length
742 // of trait ref's bound vars. So, we would end up with predicate like
743 // Self: Bar1<'a, '^0.1>
744 // 2) We can then apply the trait substs to this, ending up with
745 // T: Bar1<'^0.0, '^0.1>
746 // 3) Finally, to create the final bound vars, we concatenate the bound
747 // vars of the trait ref with those of the predicate:
749 let bound_pred = self.kind();
750 let pred_bound_vars = bound_pred.bound_vars();
751 let trait_bound_vars = trait_ref.bound_vars();
752 // 1) Self: Bar1<'a, '^0.0> -> Self: Bar1<'a, '^0.1>
754 tcx.shift_bound_var_indices(trait_bound_vars.len(), bound_pred.skip_binder());
755 // 2) Self: Bar1<'a, '^0.1> -> T: Bar1<'^0.0, '^0.1>
756 let new = EarlyBinder(shifted_pred).subst(tcx, trait_ref.skip_binder().substs);
757 // 3) ['x] + ['b] -> ['x, 'b]
759 tcx.mk_bound_variable_kinds(trait_bound_vars.iter().chain(pred_bound_vars));
760 tcx.reuse_or_mk_predicate(self, ty::Binder::bind_with_vars(new, bound_vars))
764 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
765 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
766 pub struct TraitPredicate<'tcx> {
767 pub trait_ref: TraitRef<'tcx>,
769 pub constness: BoundConstness,
771 /// If polarity is Positive: we are proving that the trait is implemented.
773 /// If polarity is Negative: we are proving that a negative impl of this trait
774 /// exists. (Note that coherence also checks whether negative impls of supertraits
775 /// exist via a series of predicates.)
777 /// If polarity is Reserved: that's a bug.
778 pub polarity: ImplPolarity,
781 pub type PolyTraitPredicate<'tcx> = ty::Binder<'tcx, TraitPredicate<'tcx>>;
783 impl<'tcx> TraitPredicate<'tcx> {
784 pub fn remap_constness(&mut self, param_env: &mut ParamEnv<'tcx>) {
785 *param_env = param_env.with_constness(self.constness.and(param_env.constness()))
788 /// Remap the constness of this predicate before emitting it for diagnostics.
789 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
790 // this is different to `remap_constness` that callees want to print this predicate
791 // in case of selection errors. `T: ~const Drop` bounds cannot end up here when the
792 // param_env is not const because it is always satisfied in non-const contexts.
793 if let hir::Constness::NotConst = param_env.constness() {
794 self.constness = ty::BoundConstness::NotConst;
798 pub fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self {
799 Self { trait_ref: self.trait_ref.with_self_ty(tcx, self_ty), ..self }
802 pub fn def_id(self) -> DefId {
803 self.trait_ref.def_id
806 pub fn self_ty(self) -> Ty<'tcx> {
807 self.trait_ref.self_ty()
811 pub fn is_const_if_const(self) -> bool {
812 self.constness == BoundConstness::ConstIfConst
815 pub fn is_constness_satisfied_by(self, constness: hir::Constness) -> bool {
816 match (self.constness, constness) {
817 (BoundConstness::NotConst, _)
818 | (BoundConstness::ConstIfConst, hir::Constness::Const) => true,
819 (BoundConstness::ConstIfConst, hir::Constness::NotConst) => false,
823 pub fn without_const(mut self) -> Self {
824 self.constness = BoundConstness::NotConst;
829 impl<'tcx> PolyTraitPredicate<'tcx> {
830 pub fn def_id(self) -> DefId {
831 // Ok to skip binder since trait `DefId` does not care about regions.
832 self.skip_binder().def_id()
835 pub fn self_ty(self) -> ty::Binder<'tcx, Ty<'tcx>> {
836 self.map_bound(|trait_ref| trait_ref.self_ty())
839 /// Remap the constness of this predicate before emitting it for diagnostics.
840 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
841 *self = self.map_bound(|mut p| {
842 p.remap_constness_diag(param_env);
848 pub fn is_const_if_const(self) -> bool {
849 self.skip_binder().is_const_if_const()
854 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
855 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
856 pub struct OutlivesPredicate<A, B>(pub A, pub B);
857 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
858 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
859 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<'tcx, RegionOutlivesPredicate<'tcx>>;
860 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<'tcx, TypeOutlivesPredicate<'tcx>>;
862 /// Encodes that `a` must be a subtype of `b`. The `a_is_expected` flag indicates
863 /// whether the `a` type is the type that we should label as "expected" when
864 /// presenting user diagnostics.
865 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
866 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
867 pub struct SubtypePredicate<'tcx> {
868 pub a_is_expected: bool,
872 pub type PolySubtypePredicate<'tcx> = ty::Binder<'tcx, SubtypePredicate<'tcx>>;
874 /// Encodes that we have to coerce *from* the `a` type to the `b` type.
875 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
876 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
877 pub struct CoercePredicate<'tcx> {
881 pub type PolyCoercePredicate<'tcx> = ty::Binder<'tcx, CoercePredicate<'tcx>>;
883 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
884 pub struct Term<'tcx> {
886 marker: PhantomData<(Ty<'tcx>, Const<'tcx>)>,
889 impl Debug for Term<'_> {
890 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
891 let data = if let Some(ty) = self.ty() {
892 format!("Term::Ty({:?})", ty)
893 } else if let Some(ct) = self.ct() {
894 format!("Term::Ct({:?})", ct)
902 impl<'tcx> From<Ty<'tcx>> for Term<'tcx> {
903 fn from(ty: Ty<'tcx>) -> Self {
904 TermKind::Ty(ty).pack()
908 impl<'tcx> From<Const<'tcx>> for Term<'tcx> {
909 fn from(c: Const<'tcx>) -> Self {
910 TermKind::Const(c).pack()
914 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Term<'tcx> {
915 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
916 self.unpack().hash_stable(hcx, hasher);
920 impl<'tcx> TypeFoldable<'tcx> for Term<'tcx> {
921 fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
922 Ok(self.unpack().try_fold_with(folder)?.pack())
926 impl<'tcx> TypeVisitable<'tcx> for Term<'tcx> {
927 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
928 self.unpack().visit_with(visitor)
932 impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for Term<'tcx> {
933 fn encode(&self, e: &mut E) {
934 self.unpack().encode(e)
938 impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for Term<'tcx> {
939 fn decode(d: &mut D) -> Self {
940 let res: TermKind<'tcx> = Decodable::decode(d);
945 impl<'tcx> Term<'tcx> {
947 pub fn unpack(self) -> TermKind<'tcx> {
948 let ptr = self.ptr.get();
949 // SAFETY: use of `Interned::new_unchecked` here is ok because these
950 // pointers were originally created from `Interned` types in `pack()`,
951 // and this is just going in the other direction.
953 match ptr & TAG_MASK {
954 TYPE_TAG => TermKind::Ty(Ty(Interned::new_unchecked(
955 &*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyKind<'tcx>>),
957 CONST_TAG => TermKind::Const(ty::Const(Interned::new_unchecked(
958 &*((ptr & !TAG_MASK) as *const ty::ConstData<'tcx>),
960 _ => core::intrinsics::unreachable(),
965 pub fn ty(&self) -> Option<Ty<'tcx>> {
966 if let TermKind::Ty(ty) = self.unpack() { Some(ty) } else { None }
969 pub fn ct(&self) -> Option<Const<'tcx>> {
970 if let TermKind::Const(c) = self.unpack() { Some(c) } else { None }
973 pub fn into_arg(self) -> GenericArg<'tcx> {
974 match self.unpack() {
975 TermKind::Ty(ty) => ty.into(),
976 TermKind::Const(c) => c.into(),
981 const TAG_MASK: usize = 0b11;
982 const TYPE_TAG: usize = 0b00;
983 const CONST_TAG: usize = 0b01;
985 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
986 #[derive(HashStable, TypeFoldable, TypeVisitable)]
987 pub enum TermKind<'tcx> {
992 impl<'tcx> TermKind<'tcx> {
994 fn pack(self) -> Term<'tcx> {
995 let (tag, ptr) = match self {
996 TermKind::Ty(ty) => {
997 // Ensure we can use the tag bits.
998 assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
999 (TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyKind<'tcx>> as usize)
1001 TermKind::Const(ct) => {
1002 // Ensure we can use the tag bits.
1003 assert_eq!(mem::align_of_val(&*ct.0.0) & TAG_MASK, 0);
1004 (CONST_TAG, ct.0.0 as *const ty::ConstData<'tcx> as usize)
1008 Term { ptr: unsafe { NonZeroUsize::new_unchecked(ptr | tag) }, marker: PhantomData }
1012 /// This kind of predicate has no *direct* correspondent in the
1013 /// syntax, but it roughly corresponds to the syntactic forms:
1015 /// 1. `T: TraitRef<..., Item = Type>`
1016 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1018 /// In particular, form #1 is "desugared" to the combination of a
1019 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1020 /// predicates. Form #2 is a broader form in that it also permits
1021 /// equality between arbitrary types. Processing an instance of
1022 /// Form #2 eventually yields one of these `ProjectionPredicate`
1023 /// instances to normalize the LHS.
1024 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
1025 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
1026 pub struct ProjectionPredicate<'tcx> {
1027 pub projection_ty: AliasTy<'tcx>,
1028 pub term: Term<'tcx>,
1031 impl<'tcx> ProjectionPredicate<'tcx> {
1032 pub fn self_ty(self) -> Ty<'tcx> {
1033 self.projection_ty.self_ty()
1036 pub fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ProjectionPredicate<'tcx> {
1037 Self { projection_ty: self.projection_ty.with_self_ty(tcx, self_ty), ..self }
1040 pub fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId {
1041 self.projection_ty.trait_def_id(tcx)
1044 pub fn def_id(self) -> DefId {
1045 self.projection_ty.def_id
1049 pub type PolyProjectionPredicate<'tcx> = Binder<'tcx, ProjectionPredicate<'tcx>>;
1051 impl<'tcx> PolyProjectionPredicate<'tcx> {
1052 /// Returns the `DefId` of the trait of the associated item being projected.
1054 pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
1055 self.skip_binder().projection_ty.trait_def_id(tcx)
1058 /// Get the [PolyTraitRef] required for this projection to be well formed.
1059 /// Note that for generic associated types the predicates of the associated
1060 /// type also need to be checked.
1062 pub fn required_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
1063 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1064 // `self.0.trait_ref` is permitted to have escaping regions.
1065 // This is because here `self` has a `Binder` and so does our
1066 // return value, so we are preserving the number of binding
1068 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1071 pub fn term(&self) -> Binder<'tcx, Term<'tcx>> {
1072 self.map_bound(|predicate| predicate.term)
1075 /// The `DefId` of the `TraitItem` for the associated type.
1077 /// Note that this is not the `DefId` of the `TraitRef` containing this
1078 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1079 pub fn projection_def_id(&self) -> DefId {
1080 // Ok to skip binder since trait `DefId` does not care about regions.
1081 self.skip_binder().projection_ty.def_id
1085 pub trait ToPolyTraitRef<'tcx> {
1086 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1089 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1090 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1091 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1095 pub trait ToPredicate<'tcx, P = Predicate<'tcx>> {
1096 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> P;
1099 impl<'tcx, T> ToPredicate<'tcx, T> for T {
1100 fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T {
1105 impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, PredicateKind<'tcx>> {
1107 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1108 tcx.mk_predicate(self)
1112 impl<'tcx> ToPredicate<'tcx> for Clause<'tcx> {
1114 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1115 tcx.mk_predicate(ty::Binder::dummy(ty::PredicateKind::Clause(self)))
1119 impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, TraitRef<'tcx>> {
1121 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1122 let pred: PolyTraitPredicate<'tcx> = self.to_predicate(tcx);
1123 pred.to_predicate(tcx)
1127 impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for Binder<'tcx, TraitRef<'tcx>> {
1129 fn to_predicate(self, _: TyCtxt<'tcx>) -> PolyTraitPredicate<'tcx> {
1130 self.map_bound(|trait_ref| TraitPredicate {
1132 constness: ty::BoundConstness::NotConst,
1133 polarity: ty::ImplPolarity::Positive,
1138 impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
1139 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1140 self.map_bound(|p| PredicateKind::Clause(Clause::Trait(p))).to_predicate(tcx)
1144 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1145 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1146 self.map_bound(|p| PredicateKind::Clause(Clause::RegionOutlives(p))).to_predicate(tcx)
1150 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1151 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1152 self.map_bound(|p| PredicateKind::Clause(Clause::TypeOutlives(p))).to_predicate(tcx)
1156 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1157 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1158 self.map_bound(|p| PredicateKind::Clause(Clause::Projection(p))).to_predicate(tcx)
1162 impl<'tcx> Predicate<'tcx> {
1163 pub fn to_opt_poly_trait_pred(self) -> Option<PolyTraitPredicate<'tcx>> {
1164 let predicate = self.kind();
1165 match predicate.skip_binder() {
1166 PredicateKind::Clause(Clause::Trait(t)) => Some(predicate.rebind(t)),
1167 PredicateKind::Clause(Clause::Projection(..))
1168 | PredicateKind::Subtype(..)
1169 | PredicateKind::Coerce(..)
1170 | PredicateKind::Clause(Clause::RegionOutlives(..))
1171 | PredicateKind::WellFormed(..)
1172 | PredicateKind::ObjectSafe(..)
1173 | PredicateKind::ClosureKind(..)
1174 | PredicateKind::Clause(Clause::TypeOutlives(..))
1175 | PredicateKind::ConstEvaluatable(..)
1176 | PredicateKind::ConstEquate(..)
1177 | PredicateKind::Ambiguous
1178 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1182 pub fn to_opt_poly_projection_pred(self) -> Option<PolyProjectionPredicate<'tcx>> {
1183 let predicate = self.kind();
1184 match predicate.skip_binder() {
1185 PredicateKind::Clause(Clause::Projection(t)) => Some(predicate.rebind(t)),
1186 PredicateKind::Clause(Clause::Trait(..))
1187 | PredicateKind::Subtype(..)
1188 | PredicateKind::Coerce(..)
1189 | PredicateKind::Clause(Clause::RegionOutlives(..))
1190 | PredicateKind::WellFormed(..)
1191 | PredicateKind::ObjectSafe(..)
1192 | PredicateKind::ClosureKind(..)
1193 | PredicateKind::Clause(Clause::TypeOutlives(..))
1194 | PredicateKind::ConstEvaluatable(..)
1195 | PredicateKind::ConstEquate(..)
1196 | PredicateKind::Ambiguous
1197 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1201 pub fn to_opt_type_outlives(self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1202 let predicate = self.kind();
1203 match predicate.skip_binder() {
1204 PredicateKind::Clause(Clause::TypeOutlives(data)) => Some(predicate.rebind(data)),
1205 PredicateKind::Clause(Clause::Trait(..))
1206 | PredicateKind::Clause(Clause::Projection(..))
1207 | PredicateKind::Subtype(..)
1208 | PredicateKind::Coerce(..)
1209 | PredicateKind::Clause(Clause::RegionOutlives(..))
1210 | PredicateKind::WellFormed(..)
1211 | PredicateKind::ObjectSafe(..)
1212 | PredicateKind::ClosureKind(..)
1213 | PredicateKind::ConstEvaluatable(..)
1214 | PredicateKind::ConstEquate(..)
1215 | PredicateKind::Ambiguous
1216 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1221 /// Represents the bounds declared on a particular set of type
1222 /// parameters. Should eventually be generalized into a flag list of
1223 /// where-clauses. You can obtain an `InstantiatedPredicates` list from a
1224 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1225 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1226 /// the `GenericPredicates` are expressed in terms of the bound type
1227 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1228 /// represented a set of bounds for some particular instantiation,
1229 /// meaning that the generic parameters have been substituted with
1233 /// ```ignore (illustrative)
1234 /// struct Foo<T, U: Bar<T>> { ... }
1236 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1237 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1238 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1239 /// [usize:Bar<isize>]]`.
1240 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
1241 pub struct InstantiatedPredicates<'tcx> {
1242 pub predicates: Vec<Predicate<'tcx>>,
1243 pub spans: Vec<Span>,
1246 impl<'tcx> InstantiatedPredicates<'tcx> {
1247 pub fn empty() -> InstantiatedPredicates<'tcx> {
1248 InstantiatedPredicates { predicates: vec![], spans: vec![] }
1251 pub fn is_empty(&self) -> bool {
1252 self.predicates.is_empty()
1255 pub fn iter(&self) -> <&Self as IntoIterator>::IntoIter {
1260 impl<'tcx> IntoIterator for InstantiatedPredicates<'tcx> {
1261 type Item = (Predicate<'tcx>, Span);
1263 type IntoIter = std::iter::Zip<std::vec::IntoIter<Predicate<'tcx>>, std::vec::IntoIter<Span>>;
1265 fn into_iter(self) -> Self::IntoIter {
1266 debug_assert_eq!(self.predicates.len(), self.spans.len());
1267 std::iter::zip(self.predicates, self.spans)
1271 impl<'a, 'tcx> IntoIterator for &'a InstantiatedPredicates<'tcx> {
1272 type Item = (Predicate<'tcx>, Span);
1274 type IntoIter = std::iter::Zip<
1275 std::iter::Copied<std::slice::Iter<'a, Predicate<'tcx>>>,
1276 std::iter::Copied<std::slice::Iter<'a, Span>>,
1279 fn into_iter(self) -> Self::IntoIter {
1280 debug_assert_eq!(self.predicates.len(), self.spans.len());
1281 std::iter::zip(self.predicates.iter().copied(), self.spans.iter().copied())
1285 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable, Lift)]
1286 #[derive(TypeFoldable, TypeVisitable)]
1287 pub struct OpaqueTypeKey<'tcx> {
1288 pub def_id: LocalDefId,
1289 pub substs: SubstsRef<'tcx>,
1292 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
1293 pub struct OpaqueHiddenType<'tcx> {
1294 /// The span of this particular definition of the opaque type. So
1297 /// ```ignore (incomplete snippet)
1298 /// type Foo = impl Baz;
1299 /// fn bar() -> Foo {
1300 /// // ^^^ This is the span we are looking for!
1304 /// In cases where the fn returns `(impl Trait, impl Trait)` or
1305 /// other such combinations, the result is currently
1306 /// over-approximated, but better than nothing.
1309 /// The type variable that represents the value of the opaque type
1310 /// that we require. In other words, after we compile this function,
1311 /// we will be created a constraint like:
1312 /// ```ignore (pseudo-rust)
1315 /// where `?C` is the value of this type variable. =) It may
1316 /// naturally refer to the type and lifetime parameters in scope
1317 /// in this function, though ultimately it should only reference
1318 /// those that are arguments to `Foo` in the constraint above. (In
1319 /// other words, `?C` should not include `'b`, even though it's a
1320 /// lifetime parameter on `foo`.)
1324 impl<'tcx> OpaqueHiddenType<'tcx> {
1325 pub fn report_mismatch(&self, other: &Self, tcx: TyCtxt<'tcx>) {
1326 // Found different concrete types for the opaque type.
1327 let sub_diag = if self.span == other.span {
1328 TypeMismatchReason::ConflictType { span: self.span }
1330 TypeMismatchReason::PreviousUse { span: self.span }
1332 tcx.sess.emit_err(OpaqueHiddenTypeMismatch {
1335 other_span: other.span,
1340 #[instrument(level = "debug", skip(tcx), ret)]
1341 pub fn remap_generic_params_to_declaration_params(
1343 opaque_type_key: OpaqueTypeKey<'tcx>,
1345 // typeck errors have subpar spans for opaque types, so delay error reporting until borrowck.
1346 ignore_errors: bool,
1348 let OpaqueTypeKey { def_id, substs } = opaque_type_key;
1350 // Use substs to build up a reverse map from regions to their
1351 // identity mappings. This is necessary because of `impl
1352 // Trait` lifetimes are computed by replacing existing
1353 // lifetimes with 'static and remapping only those used in the
1354 // `impl Trait` return type, resulting in the parameters
1356 let id_substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
1359 // This zip may have several times the same lifetime in `substs` paired with a different
1360 // lifetime from `id_substs`. Simply `collect`ing the iterator is the correct behaviour:
1361 // it will pick the last one, which is the one we introduced in the impl-trait desugaring.
1362 let map = substs.iter().zip(id_substs).collect();
1363 debug!("map = {:#?}", map);
1365 // Convert the type from the function into a type valid outside
1366 // the function, by replacing invalid regions with 'static,
1367 // after producing an error for each of them.
1368 self.fold_with(&mut opaque_types::ReverseMapper::new(tcx, map, self.span, ignore_errors))
1372 /// The "placeholder index" fully defines a placeholder region, type, or const. Placeholders are
1373 /// identified by both a universe, as well as a name residing within that universe. Distinct bound
1374 /// regions/types/consts within the same universe simply have an unknown relationship to one
1376 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
1377 #[derive(HashStable, TyEncodable, TyDecodable)]
1378 pub struct Placeholder<T> {
1379 pub universe: UniverseIndex,
1383 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
1385 pub type PlaceholderType = Placeholder<BoundVar>;
1387 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1388 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]
1389 pub struct BoundConst<'tcx> {
1394 pub type PlaceholderConst<'tcx> = Placeholder<BoundVar>;
1396 /// A `DefId` which, in case it is a const argument, is potentially bundled with
1397 /// the `DefId` of the generic parameter it instantiates.
1399 /// This is used to avoid calls to `type_of` for const arguments during typeck
1400 /// which cause cycle errors.
1405 /// fn foo<const N: usize>(&self) -> [u8; N] { [0; N] }
1406 /// // ^ const parameter
1410 /// fn foo<const M: u8>(&self) -> usize { 42 }
1411 /// // ^ const parameter
1416 /// let _b = a.foo::<{ 3 + 7 }>();
1417 /// // ^^^^^^^^^ const argument
1421 /// Let's look at the call `a.foo::<{ 3 + 7 }>()` here. We do not know
1422 /// which `foo` is used until we know the type of `a`.
1424 /// We only know the type of `a` once we are inside of `typeck(main)`.
1425 /// We also end up normalizing the type of `_b` during `typeck(main)` which
1426 /// requires us to evaluate the const argument.
1428 /// To evaluate that const argument we need to know its type,
1429 /// which we would get using `type_of(const_arg)`. This requires us to
1430 /// resolve `foo` as it can be either `usize` or `u8` in this example.
1431 /// However, resolving `foo` once again requires `typeck(main)` to get the type of `a`,
1432 /// which results in a cycle.
1434 /// In short we must not call `type_of(const_arg)` during `typeck(main)`.
1436 /// When first creating the `ty::Const` of the const argument inside of `typeck` we have
1437 /// already resolved `foo` so we know which const parameter this argument instantiates.
1438 /// This means that we also know the expected result of `type_of(const_arg)` even if we
1439 /// aren't allowed to call that query: it is equal to `type_of(const_param)` which is
1440 /// trivial to compute.
1442 /// If we now want to use that constant in a place which potentially needs its type
1443 /// we also pass the type of its `const_param`. This is the point of `WithOptConstParam`,
1444 /// except that instead of a `Ty` we bundle the `DefId` of the const parameter.
1445 /// Meaning that we need to use `type_of(const_param_did)` if `const_param_did` is `Some`
1446 /// to get the type of `did`.
1447 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift, TyEncodable, TyDecodable)]
1448 #[derive(PartialEq, Eq, PartialOrd, Ord)]
1449 #[derive(Hash, HashStable)]
1450 pub struct WithOptConstParam<T> {
1452 /// The `DefId` of the corresponding generic parameter in case `did` is
1453 /// a const argument.
1455 /// Note that even if `did` is a const argument, this may still be `None`.
1456 /// All queries taking `WithOptConstParam` start by calling `tcx.opt_const_param_of(def.did)`
1457 /// to potentially update `param_did` in the case it is `None`.
1458 pub const_param_did: Option<DefId>,
1461 impl<T> WithOptConstParam<T> {
1462 /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`.
1464 pub fn unknown(did: T) -> WithOptConstParam<T> {
1465 WithOptConstParam { did, const_param_did: None }
1469 impl WithOptConstParam<LocalDefId> {
1470 /// Returns `Some((did, param_did))` if `def_id` is a const argument,
1471 /// `None` otherwise.
1473 pub fn try_lookup(did: LocalDefId, tcx: TyCtxt<'_>) -> Option<(LocalDefId, DefId)> {
1474 tcx.opt_const_param_of(did).map(|param_did| (did, param_did))
1477 /// In case `self` is unknown but `self.did` is a const argument, this returns
1478 /// a `WithOptConstParam` with the correct `const_param_did`.
1480 pub fn try_upgrade(self, tcx: TyCtxt<'_>) -> Option<WithOptConstParam<LocalDefId>> {
1481 if self.const_param_did.is_none() {
1482 if let const_param_did @ Some(_) = tcx.opt_const_param_of(self.did) {
1483 return Some(WithOptConstParam { did: self.did, const_param_did });
1490 pub fn to_global(self) -> WithOptConstParam<DefId> {
1491 WithOptConstParam { did: self.did.to_def_id(), const_param_did: self.const_param_did }
1494 pub fn def_id_for_type_of(self) -> DefId {
1495 if let Some(did) = self.const_param_did { did } else { self.did.to_def_id() }
1499 impl WithOptConstParam<DefId> {
1500 pub fn as_local(self) -> Option<WithOptConstParam<LocalDefId>> {
1503 .map(|did| WithOptConstParam { did, const_param_did: self.const_param_did })
1506 pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)> {
1507 if let Some(param_did) = self.const_param_did {
1508 if let Some(did) = self.did.as_local() {
1509 return Some((did, param_did));
1516 pub fn is_local(self) -> bool {
1520 pub fn def_id_for_type_of(self) -> DefId {
1521 self.const_param_did.unwrap_or(self.did)
1525 /// When type checking, we use the `ParamEnv` to track
1526 /// details about the set of where-clauses that are in scope at this
1527 /// particular point.
1528 #[derive(Copy, Clone, Hash, PartialEq, Eq)]
1529 pub struct ParamEnv<'tcx> {
1530 /// This packs both caller bounds and the reveal enum into one pointer.
1532 /// Caller bounds are `Obligation`s that the caller must satisfy. This is
1533 /// basically the set of bounds on the in-scope type parameters, translated
1534 /// into `Obligation`s, and elaborated and normalized.
1536 /// Use the `caller_bounds()` method to access.
1538 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1539 /// want `Reveal::All`.
1541 /// Note: This is packed, use the reveal() method to access it.
1542 packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, ParamTag, true>,
1545 #[derive(Copy, Clone)]
1547 reveal: traits::Reveal,
1548 constness: hir::Constness,
1551 unsafe impl rustc_data_structures::tagged_ptr::Tag for ParamTag {
1552 const BITS: usize = 2;
1554 fn into_usize(self) -> usize {
1556 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst } => 0,
1557 Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst } => 1,
1558 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const } => 2,
1559 Self { reveal: traits::Reveal::All, constness: hir::Constness::Const } => 3,
1563 unsafe fn from_usize(ptr: usize) -> Self {
1565 0 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst },
1566 1 => Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst },
1567 2 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const },
1568 3 => Self { reveal: traits::Reveal::All, constness: hir::Constness::Const },
1569 _ => std::hint::unreachable_unchecked(),
1574 impl<'tcx> fmt::Debug for ParamEnv<'tcx> {
1575 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1576 f.debug_struct("ParamEnv")
1577 .field("caller_bounds", &self.caller_bounds())
1578 .field("reveal", &self.reveal())
1579 .field("constness", &self.constness())
1584 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx> {
1585 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1586 self.caller_bounds().hash_stable(hcx, hasher);
1587 self.reveal().hash_stable(hcx, hasher);
1588 self.constness().hash_stable(hcx, hasher);
1592 impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
1593 fn try_fold_with<F: ty::fold::FallibleTypeFolder<'tcx>>(
1596 ) -> Result<Self, F::Error> {
1598 self.caller_bounds().try_fold_with(folder)?,
1599 self.reveal().try_fold_with(folder)?,
1605 impl<'tcx> TypeVisitable<'tcx> for ParamEnv<'tcx> {
1606 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
1607 self.caller_bounds().visit_with(visitor)?;
1608 self.reveal().visit_with(visitor)
1612 impl<'tcx> ParamEnv<'tcx> {
1613 /// Construct a trait environment suitable for contexts where
1614 /// there are no where-clauses in scope. Hidden types (like `impl
1615 /// Trait`) are left hidden, so this is suitable for ordinary
1618 pub fn empty() -> Self {
1619 Self::new(List::empty(), Reveal::UserFacing, hir::Constness::NotConst)
1623 pub fn caller_bounds(self) -> &'tcx List<Predicate<'tcx>> {
1624 self.packed.pointer()
1628 pub fn reveal(self) -> traits::Reveal {
1629 self.packed.tag().reveal
1633 pub fn constness(self) -> hir::Constness {
1634 self.packed.tag().constness
1638 pub fn is_const(self) -> bool {
1639 self.packed.tag().constness == hir::Constness::Const
1642 /// Construct a trait environment with no where-clauses in scope
1643 /// where the values of all `impl Trait` and other hidden types
1644 /// are revealed. This is suitable for monomorphized, post-typeck
1645 /// environments like codegen or doing optimizations.
1647 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1648 /// or invoke `param_env.with_reveal_all()`.
1650 pub fn reveal_all() -> Self {
1651 Self::new(List::empty(), Reveal::All, hir::Constness::NotConst)
1654 /// Construct a trait environment with the given set of predicates.
1657 caller_bounds: &'tcx List<Predicate<'tcx>>,
1659 constness: hir::Constness,
1661 ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, ParamTag { reveal, constness }) }
1664 pub fn with_user_facing(mut self) -> Self {
1665 self.packed.set_tag(ParamTag { reveal: Reveal::UserFacing, ..self.packed.tag() });
1670 pub fn with_constness(mut self, constness: hir::Constness) -> Self {
1671 self.packed.set_tag(ParamTag { constness, ..self.packed.tag() });
1676 pub fn with_const(mut self) -> Self {
1677 self.packed.set_tag(ParamTag { constness: hir::Constness::Const, ..self.packed.tag() });
1682 pub fn without_const(mut self) -> Self {
1683 self.packed.set_tag(ParamTag { constness: hir::Constness::NotConst, ..self.packed.tag() });
1688 pub fn remap_constness_with(&mut self, mut constness: ty::BoundConstness) {
1689 *self = self.with_constness(constness.and(self.constness()))
1692 /// Returns a new parameter environment with the same clauses, but
1693 /// which "reveals" the true results of projections in all cases
1694 /// (even for associated types that are specializable). This is
1695 /// the desired behavior during codegen and certain other special
1696 /// contexts; normally though we want to use `Reveal::UserFacing`,
1697 /// which is the default.
1698 /// All opaque types in the caller_bounds of the `ParamEnv`
1699 /// will be normalized to their underlying types.
1700 /// See PR #65989 and issue #65918 for more details
1701 pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self {
1702 if self.packed.tag().reveal == traits::Reveal::All {
1707 tcx.reveal_opaque_types_in_bounds(self.caller_bounds()),
1713 /// Returns this same environment but with no caller bounds.
1715 pub fn without_caller_bounds(self) -> Self {
1716 Self::new(List::empty(), self.reveal(), self.constness())
1719 /// Creates a suitable environment in which to perform trait
1720 /// queries on the given value. When type-checking, this is simply
1721 /// the pair of the environment plus value. But when reveal is set to
1722 /// All, then if `value` does not reference any type parameters, we will
1723 /// pair it with the empty environment. This improves caching and is generally
1726 /// N.B., we preserve the environment when type-checking because it
1727 /// is possible for the user to have wacky where-clauses like
1728 /// `where Box<u32>: Copy`, which are clearly never
1729 /// satisfiable. We generally want to behave as if they were true,
1730 /// although the surrounding function is never reachable.
1731 pub fn and<T: TypeVisitable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1732 match self.reveal() {
1733 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1736 if value.is_global() {
1737 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1739 ParamEnvAnd { param_env: self, value }
1746 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
1747 // the constness of trait bounds is being propagated correctly.
1748 impl<'tcx> PolyTraitRef<'tcx> {
1750 pub fn with_constness(self, constness: BoundConstness) -> PolyTraitPredicate<'tcx> {
1751 self.map_bound(|trait_ref| ty::TraitPredicate {
1754 polarity: ty::ImplPolarity::Positive,
1759 pub fn without_const(self) -> PolyTraitPredicate<'tcx> {
1760 self.with_constness(BoundConstness::NotConst)
1764 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
1765 #[derive(HashStable, Lift)]
1766 pub struct ParamEnvAnd<'tcx, T> {
1767 pub param_env: ParamEnv<'tcx>,
1771 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1772 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1773 (self.param_env, self.value)
1777 pub fn without_const(mut self) -> Self {
1778 self.param_env = self.param_env.without_const();
1783 #[derive(Copy, Clone, Debug, HashStable, Encodable, Decodable)]
1784 pub struct Destructor {
1785 /// The `DefId` of the destructor method
1787 /// The constness of the destructor method
1788 pub constness: hir::Constness,
1792 #[derive(HashStable, TyEncodable, TyDecodable)]
1793 pub struct VariantFlags: u32 {
1794 const NO_VARIANT_FLAGS = 0;
1795 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1796 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1797 /// Indicates whether this variant was obtained as part of recovering from
1798 /// a syntactic error. May be incomplete or bogus.
1799 const IS_RECOVERED = 1 << 1;
1803 /// Definition of a variant -- a struct's fields or an enum variant.
1804 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
1805 pub struct VariantDef {
1806 /// `DefId` that identifies the variant itself.
1807 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1809 /// `DefId` that identifies the variant's constructor.
1810 /// If this variant is a struct variant, then this is `None`.
1811 pub ctor: Option<(CtorKind, DefId)>,
1812 /// Variant or struct name.
1814 /// Discriminant of this variant.
1815 pub discr: VariantDiscr,
1816 /// Fields of this variant.
1817 pub fields: Vec<FieldDef>,
1818 /// Flags of the variant (e.g. is field list non-exhaustive)?
1819 flags: VariantFlags,
1823 /// Creates a new `VariantDef`.
1825 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1826 /// represents an enum variant).
1828 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1829 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1831 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1832 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1833 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1834 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1835 /// built-in trait), and we do not want to load attributes twice.
1837 /// If someone speeds up attribute loading to not be a performance concern, they can
1838 /// remove this hack and use the constructor `DefId` everywhere.
1841 variant_did: Option<DefId>,
1842 ctor: Option<(CtorKind, DefId)>,
1843 discr: VariantDiscr,
1844 fields: Vec<FieldDef>,
1848 is_field_list_non_exhaustive: bool,
1851 "VariantDef::new(name = {:?}, variant_did = {:?}, ctor = {:?}, discr = {:?},
1852 fields = {:?}, adt_kind = {:?}, parent_did = {:?})",
1853 name, variant_did, ctor, discr, fields, adt_kind, parent_did,
1856 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1857 if is_field_list_non_exhaustive {
1858 flags |= VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1862 flags |= VariantFlags::IS_RECOVERED;
1865 VariantDef { def_id: variant_did.unwrap_or(parent_did), ctor, name, discr, fields, flags }
1868 /// Is this field list non-exhaustive?
1870 pub fn is_field_list_non_exhaustive(&self) -> bool {
1871 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1874 /// Was this variant obtained as part of recovering from a syntactic error?
1876 pub fn is_recovered(&self) -> bool {
1877 self.flags.intersects(VariantFlags::IS_RECOVERED)
1880 /// Computes the `Ident` of this variant by looking up the `Span`
1881 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
1882 Ident::new(self.name, tcx.def_ident_span(self.def_id).unwrap())
1886 pub fn ctor_kind(&self) -> Option<CtorKind> {
1887 self.ctor.map(|(kind, _)| kind)
1891 pub fn ctor_def_id(&self) -> Option<DefId> {
1892 self.ctor.map(|(_, def_id)| def_id)
1896 impl PartialEq for VariantDef {
1898 fn eq(&self, other: &Self) -> bool {
1899 // There should be only one `VariantDef` for each `def_id`, therefore
1900 // it is fine to implement `PartialEq` only based on `def_id`.
1902 // Below, we exhaustively destructure `self` and `other` so that if the
1903 // definition of `VariantDef` changes, a compile-error will be produced,
1904 // reminding us to revisit this assumption.
1906 let Self { def_id: lhs_def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = &self;
1907 let Self { def_id: rhs_def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = other;
1908 lhs_def_id == rhs_def_id
1912 impl Eq for VariantDef {}
1914 impl Hash for VariantDef {
1916 fn hash<H: Hasher>(&self, s: &mut H) {
1917 // There should be only one `VariantDef` for each `def_id`, therefore
1918 // it is fine to implement `Hash` only based on `def_id`.
1920 // Below, we exhaustively destructure `self` so that if the definition
1921 // of `VariantDef` changes, a compile-error will be produced, reminding
1922 // us to revisit this assumption.
1924 let Self { def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = &self;
1929 #[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
1930 pub enum VariantDiscr {
1931 /// Explicit value for this variant, i.e., `X = 123`.
1932 /// The `DefId` corresponds to the embedded constant.
1935 /// The previous variant's discriminant plus one.
1936 /// For efficiency reasons, the distance from the
1937 /// last `Explicit` discriminant is being stored,
1938 /// or `0` for the first variant, if it has none.
1942 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
1943 pub struct FieldDef {
1946 pub vis: Visibility<DefId>,
1949 impl PartialEq for FieldDef {
1951 fn eq(&self, other: &Self) -> bool {
1952 // There should be only one `FieldDef` for each `did`, therefore it is
1953 // fine to implement `PartialEq` only based on `did`.
1955 // Below, we exhaustively destructure `self` so that if the definition
1956 // of `FieldDef` changes, a compile-error will be produced, reminding
1957 // us to revisit this assumption.
1959 let Self { did: lhs_did, name: _, vis: _ } = &self;
1961 let Self { did: rhs_did, name: _, vis: _ } = other;
1967 impl Eq for FieldDef {}
1969 impl Hash for FieldDef {
1971 fn hash<H: Hasher>(&self, s: &mut H) {
1972 // There should be only one `FieldDef` for each `did`, therefore it is
1973 // fine to implement `Hash` only based on `did`.
1975 // Below, we exhaustively destructure `self` so that if the definition
1976 // of `FieldDef` changes, a compile-error will be produced, reminding
1977 // us to revisit this assumption.
1979 let Self { did, name: _, vis: _ } = &self;
1985 impl<'tcx> FieldDef {
1986 /// Returns the type of this field. The resulting type is not normalized. The `subst` is
1987 /// typically obtained via the second field of [`TyKind::Adt`].
1988 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
1989 tcx.bound_type_of(self.did).subst(tcx, subst)
1992 /// Computes the `Ident` of this variant by looking up the `Span`
1993 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
1994 Ident::new(self.name, tcx.def_ident_span(self.did).unwrap())
1998 pub type Attributes<'tcx> = impl Iterator<Item = &'tcx ast::Attribute>;
1999 #[derive(Debug, PartialEq, Eq)]
2000 pub enum ImplOverlapKind {
2001 /// These impls are always allowed to overlap.
2003 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
2006 /// These impls are allowed to overlap, but that raises
2007 /// an issue #33140 future-compatibility warning.
2009 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2010 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2012 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2013 /// that difference, making what reduces to the following set of impls:
2015 /// ```compile_fail,(E0119)
2017 /// impl Trait for dyn Send + Sync {}
2018 /// impl Trait for dyn Sync + Send {}
2021 /// Obviously, once we made these types be identical, that code causes a coherence
2022 /// error and a fairly big headache for us. However, luckily for us, the trait
2023 /// `Trait` used in this case is basically a marker trait, and therefore having
2024 /// overlapping impls for it is sound.
2026 /// To handle this, we basically regard the trait as a marker trait, with an additional
2027 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2028 /// it has the following restrictions:
2030 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2032 /// 2. The trait-ref of both impls must be equal.
2033 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2035 /// 4. Neither of the impls can have any where-clauses.
2037 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2041 impl<'tcx> TyCtxt<'tcx> {
2042 pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> {
2043 self.typeck(self.hir().body_owner_def_id(body))
2046 pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
2047 self.associated_items(id)
2048 .in_definition_order()
2049 .filter(move |item| item.kind == AssocKind::Fn && item.defaultness(self).has_value())
2052 pub fn repr_options_of_def(self, did: DefId) -> ReprOptions {
2053 let mut flags = ReprFlags::empty();
2054 let mut size = None;
2055 let mut max_align: Option<Align> = None;
2056 let mut min_pack: Option<Align> = None;
2058 // Generate a deterministically-derived seed from the item's path hash
2059 // to allow for cross-crate compilation to actually work
2060 let mut field_shuffle_seed = self.def_path_hash(did).0.to_smaller_hash();
2062 // If the user defined a custom seed for layout randomization, xor the item's
2063 // path hash with the user defined seed, this will allowing determinism while
2064 // still allowing users to further randomize layout generation for e.g. fuzzing
2065 if let Some(user_seed) = self.sess.opts.unstable_opts.layout_seed {
2066 field_shuffle_seed ^= user_seed;
2069 for attr in self.get_attrs(did, sym::repr) {
2070 for r in attr::parse_repr_attr(&self.sess, attr) {
2071 flags.insert(match r {
2072 attr::ReprC => ReprFlags::IS_C,
2073 attr::ReprPacked(pack) => {
2074 let pack = Align::from_bytes(pack as u64).unwrap();
2075 min_pack = Some(if let Some(min_pack) = min_pack {
2082 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2083 attr::ReprSimd => ReprFlags::IS_SIMD,
2084 attr::ReprInt(i) => {
2085 size = Some(match i {
2086 attr::IntType::SignedInt(x) => match x {
2087 ast::IntTy::Isize => IntegerType::Pointer(true),
2088 ast::IntTy::I8 => IntegerType::Fixed(Integer::I8, true),
2089 ast::IntTy::I16 => IntegerType::Fixed(Integer::I16, true),
2090 ast::IntTy::I32 => IntegerType::Fixed(Integer::I32, true),
2091 ast::IntTy::I64 => IntegerType::Fixed(Integer::I64, true),
2092 ast::IntTy::I128 => IntegerType::Fixed(Integer::I128, true),
2094 attr::IntType::UnsignedInt(x) => match x {
2095 ast::UintTy::Usize => IntegerType::Pointer(false),
2096 ast::UintTy::U8 => IntegerType::Fixed(Integer::I8, false),
2097 ast::UintTy::U16 => IntegerType::Fixed(Integer::I16, false),
2098 ast::UintTy::U32 => IntegerType::Fixed(Integer::I32, false),
2099 ast::UintTy::U64 => IntegerType::Fixed(Integer::I64, false),
2100 ast::UintTy::U128 => IntegerType::Fixed(Integer::I128, false),
2105 attr::ReprAlign(align) => {
2106 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2113 // If `-Z randomize-layout` was enabled for the type definition then we can
2114 // consider performing layout randomization
2115 if self.sess.opts.unstable_opts.randomize_layout {
2116 flags.insert(ReprFlags::RANDOMIZE_LAYOUT);
2119 // This is here instead of layout because the choice must make it into metadata.
2120 if !self.consider_optimizing(|| format!("Reorder fields of {:?}", self.def_path_str(did))) {
2121 flags.insert(ReprFlags::IS_LINEAR);
2124 ReprOptions { int: size, align: max_align, pack: min_pack, flags, field_shuffle_seed }
2127 /// Look up the name of a definition across crates. This does not look at HIR.
2128 pub fn opt_item_name(self, def_id: DefId) -> Option<Symbol> {
2129 if let Some(cnum) = def_id.as_crate_root() {
2130 Some(self.crate_name(cnum))
2132 let def_key = self.def_key(def_id);
2133 match def_key.disambiguated_data.data {
2134 // The name of a constructor is that of its parent.
2135 rustc_hir::definitions::DefPathData::Ctor => self
2136 .opt_item_name(DefId { krate: def_id.krate, index: def_key.parent.unwrap() }),
2137 // The name of opaque types only exists in HIR.
2138 rustc_hir::definitions::DefPathData::ImplTrait
2139 if let Some(def_id) = def_id.as_local() =>
2140 self.hir().opt_name(self.hir().local_def_id_to_hir_id(def_id)),
2141 _ => def_key.get_opt_name(),
2146 /// Look up the name of a definition across crates. This does not look at HIR.
2148 /// This method will ICE if the corresponding item does not have a name. In these cases, use
2149 /// [`opt_item_name`] instead.
2151 /// [`opt_item_name`]: Self::opt_item_name
2152 pub fn item_name(self, id: DefId) -> Symbol {
2153 self.opt_item_name(id).unwrap_or_else(|| {
2154 bug!("item_name: no name for {:?}", self.def_path(id));
2158 /// Look up the name and span of a definition.
2160 /// See [`item_name`][Self::item_name] for more information.
2161 pub fn opt_item_ident(self, def_id: DefId) -> Option<Ident> {
2162 let def = self.opt_item_name(def_id)?;
2165 .and_then(|id| self.def_ident_span(id))
2166 .unwrap_or(rustc_span::DUMMY_SP);
2167 Some(Ident::new(def, span))
2170 pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> {
2171 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2172 Some(self.associated_item(def_id))
2178 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2182 .position(|field| self.hygienic_eq(ident, field.ident(self), variant.def_id))
2185 /// Returns `true` if the impls are the same polarity and the trait either
2186 /// has no items or is annotated `#[marker]` and prevents item overrides.
2187 pub fn impls_are_allowed_to_overlap(
2191 ) -> Option<ImplOverlapKind> {
2192 // If either trait impl references an error, they're allowed to overlap,
2193 // as one of them essentially doesn't exist.
2194 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.subst_identity().references_error())
2196 .impl_trait_ref(def_id2)
2197 .map_or(false, |tr| tr.subst_identity().references_error())
2199 return Some(ImplOverlapKind::Permitted { marker: false });
2202 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2203 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
2204 // `#[rustc_reservation_impl]` impls don't overlap with anything
2206 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2209 return Some(ImplOverlapKind::Permitted { marker: false });
2211 (ImplPolarity::Positive, ImplPolarity::Negative)
2212 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
2213 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2215 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2220 (ImplPolarity::Positive, ImplPolarity::Positive)
2221 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2224 let is_marker_overlap = {
2225 let is_marker_impl = |def_id: DefId| -> bool {
2226 let trait_ref = self.impl_trait_ref(def_id);
2227 trait_ref.map_or(false, |tr| self.trait_def(tr.skip_binder().def_id).is_marker)
2229 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2232 if is_marker_overlap {
2234 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2237 Some(ImplOverlapKind::Permitted { marker: true })
2239 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2240 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2241 if self_ty1 == self_ty2 {
2243 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2246 return Some(ImplOverlapKind::Issue33140);
2249 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2250 def_id1, def_id2, self_ty1, self_ty2
2256 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
2261 /// Returns `ty::VariantDef` if `res` refers to a struct,
2262 /// or variant or their constructors, panics otherwise.
2263 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2265 Res::Def(DefKind::Variant, did) => {
2266 let enum_did = self.parent(did);
2267 self.adt_def(enum_did).variant_with_id(did)
2269 Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(),
2270 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2271 let variant_did = self.parent(variant_ctor_did);
2272 let enum_did = self.parent(variant_did);
2273 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2275 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2276 let struct_did = self.parent(ctor_did);
2277 self.adt_def(struct_did).non_enum_variant()
2279 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
2283 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2284 #[instrument(skip(self), level = "debug")]
2285 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
2287 ty::InstanceDef::Item(def) => {
2288 debug!("calling def_kind on def: {:?}", def);
2289 let def_kind = self.def_kind(def.did);
2290 debug!("returned from def_kind: {:?}", def_kind);
2293 | DefKind::Static(..)
2294 | DefKind::AssocConst
2296 | DefKind::AnonConst
2297 | DefKind::InlineConst => self.mir_for_ctfe_opt_const_arg(def),
2298 // If the caller wants `mir_for_ctfe` of a function they should not be using
2299 // `instance_mir`, so we'll assume const fn also wants the optimized version.
2301 assert_eq!(def.const_param_did, None);
2302 self.optimized_mir(def.did)
2306 ty::InstanceDef::VTableShim(..)
2307 | ty::InstanceDef::ReifyShim(..)
2308 | ty::InstanceDef::Intrinsic(..)
2309 | ty::InstanceDef::FnPtrShim(..)
2310 | ty::InstanceDef::Virtual(..)
2311 | ty::InstanceDef::ClosureOnceShim { .. }
2312 | ty::InstanceDef::DropGlue(..)
2313 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance),
2317 // FIXME(@lcnr): Remove this function.
2318 pub fn get_attrs_unchecked(self, did: DefId) -> &'tcx [ast::Attribute] {
2319 if let Some(did) = did.as_local() {
2320 self.hir().attrs(self.hir().local_def_id_to_hir_id(did))
2322 self.item_attrs(did)
2326 /// Gets all attributes with the given name.
2327 pub fn get_attrs(self, did: DefId, attr: Symbol) -> ty::Attributes<'tcx> {
2328 let filter_fn = move |a: &&ast::Attribute| a.has_name(attr);
2329 if let Some(did) = did.as_local() {
2330 self.hir().attrs(self.hir().local_def_id_to_hir_id(did)).iter().filter(filter_fn)
2331 } else if cfg!(debug_assertions) && rustc_feature::is_builtin_only_local(attr) {
2332 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2334 self.item_attrs(did).iter().filter(filter_fn)
2338 pub fn get_attr(self, did: DefId, attr: Symbol) -> Option<&'tcx ast::Attribute> {
2339 if cfg!(debug_assertions) && !rustc_feature::is_valid_for_get_attr(attr) {
2340 bug!("get_attr: unexpected called with DefId `{:?}`, attr `{:?}`", did, attr);
2342 self.get_attrs(did, attr).next()
2346 /// Determines whether an item is annotated with an attribute.
2347 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
2348 if cfg!(debug_assertions) && !did.is_local() && rustc_feature::is_builtin_only_local(attr) {
2349 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2351 self.get_attrs(did, attr).next().is_some()
2355 /// Returns `true` if this is an `auto trait`.
2356 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2357 self.trait_def(trait_def_id).has_auto_impl
2360 /// Returns `true` if this is a trait alias.
2361 pub fn trait_is_alias(self, trait_def_id: DefId) -> bool {
2362 self.def_kind(trait_def_id) == DefKind::TraitAlias
2365 pub fn trait_is_coinductive(self, trait_def_id: DefId) -> bool {
2366 self.trait_is_auto(trait_def_id) || self.lang_items().sized_trait() == Some(trait_def_id)
2369 /// Returns layout of a generator. Layout might be unavailable if the
2370 /// generator is tainted by errors.
2371 pub fn generator_layout(self, def_id: DefId) -> Option<&'tcx GeneratorLayout<'tcx>> {
2372 self.optimized_mir(def_id).generator_layout()
2375 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
2376 /// If it implements no trait, returns `None`.
2377 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2378 self.impl_trait_ref(def_id).map(|tr| tr.skip_binder().def_id)
2381 /// If the given `DefId` describes an item belonging to a trait,
2382 /// returns the `DefId` of the trait that the trait item belongs to;
2383 /// otherwise, returns `None`.
2384 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2385 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2386 let parent = self.parent(def_id);
2387 if let DefKind::Trait | DefKind::TraitAlias = self.def_kind(parent) {
2388 return Some(parent);
2394 /// If the given `DefId` describes a method belonging to an impl, returns the
2395 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
2396 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2397 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2398 let parent = self.parent(def_id);
2399 if let DefKind::Impl = self.def_kind(parent) {
2400 return Some(parent);
2406 /// If the given `DefId` belongs to a trait that was automatically derived, returns `true`.
2407 pub fn is_builtin_derive(self, def_id: DefId) -> bool {
2408 self.has_attr(def_id, sym::automatically_derived)
2411 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2412 /// with the name of the crate containing the impl.
2413 pub fn span_of_impl(self, impl_def_id: DefId) -> Result<Span, Symbol> {
2414 if let Some(impl_def_id) = impl_def_id.as_local() {
2415 Ok(self.def_span(impl_def_id))
2417 Err(self.crate_name(impl_def_id.krate))
2421 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
2422 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2423 /// definition's parent/scope to perform comparison.
2424 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2425 // We could use `Ident::eq` here, but we deliberately don't. The name
2426 // comparison fails frequently, and we want to avoid the expensive
2427 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
2428 use_name.name == def_name.name
2432 .hygienic_eq(def_name.span.ctxt(), self.expn_that_defined(def_parent_def_id))
2435 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
2436 ident.span.normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope));
2440 // FIXME(vincenzoapalzzo): move the HirId to a LocalDefId
2441 pub fn adjust_ident_and_get_scope(
2446 ) -> (Ident, DefId) {
2449 .normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope))
2450 .and_then(|actual_expansion| actual_expansion.expn_data().parent_module)
2451 .unwrap_or_else(|| self.parent_module(block).to_def_id());
2455 /// Returns `true` if the debuginfo for `span` should be collapsed to the outermost expansion
2456 /// site. Only applies when `Span` is the result of macro expansion.
2458 /// - If the `collapse_debuginfo` feature is enabled then debuginfo is not collapsed by default
2459 /// and only when a macro definition is annotated with `#[collapse_debuginfo]`.
2460 /// - If `collapse_debuginfo` is not enabled, then debuginfo is collapsed by default.
2462 /// When `-Zdebug-macros` is provided then debuginfo will never be collapsed.
2463 pub fn should_collapse_debuginfo(self, span: Span) -> bool {
2464 !self.sess.opts.unstable_opts.debug_macros
2465 && if self.features().collapse_debuginfo {
2466 span.in_macro_expansion_with_collapse_debuginfo()
2468 // Inlined spans should not be collapsed as that leads to all of the
2469 // inlined code being attributed to the inline callsite.
2470 span.from_expansion() && !span.is_inlined()
2474 pub fn is_object_safe(self, key: DefId) -> bool {
2475 self.object_safety_violations(key).is_empty()
2479 pub fn is_const_fn_raw(self, def_id: DefId) -> bool {
2481 self.def_kind(def_id),
2482 DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(..) | DefKind::Closure
2483 ) && self.constness(def_id) == hir::Constness::Const
2487 pub fn is_const_default_method(self, def_id: DefId) -> bool {
2488 matches!(self.trait_of_item(def_id), Some(trait_id) if self.has_attr(trait_id, sym::const_trait))
2491 pub fn impl_trait_in_trait_parent(self, mut def_id: DefId) -> DefId {
2492 while let def_kind = self.def_kind(def_id) && def_kind != DefKind::AssocFn {
2493 debug_assert_eq!(def_kind, DefKind::ImplTraitPlaceholder);
2494 def_id = self.parent(def_id);
2500 /// Yields the parent function's `LocalDefId` if `def_id` is an `impl Trait` definition.
2501 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<LocalDefId> {
2502 let def_id = def_id.as_local()?;
2503 if let Node::Item(item) = tcx.hir().get_by_def_id(def_id) {
2504 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
2505 return match opaque_ty.origin {
2506 hir::OpaqueTyOrigin::FnReturn(parent) | hir::OpaqueTyOrigin::AsyncFn(parent) => {
2509 hir::OpaqueTyOrigin::TyAlias => None,
2516 pub fn int_ty(ity: ast::IntTy) -> IntTy {
2518 ast::IntTy::Isize => IntTy::Isize,
2519 ast::IntTy::I8 => IntTy::I8,
2520 ast::IntTy::I16 => IntTy::I16,
2521 ast::IntTy::I32 => IntTy::I32,
2522 ast::IntTy::I64 => IntTy::I64,
2523 ast::IntTy::I128 => IntTy::I128,
2527 pub fn uint_ty(uty: ast::UintTy) -> UintTy {
2529 ast::UintTy::Usize => UintTy::Usize,
2530 ast::UintTy::U8 => UintTy::U8,
2531 ast::UintTy::U16 => UintTy::U16,
2532 ast::UintTy::U32 => UintTy::U32,
2533 ast::UintTy::U64 => UintTy::U64,
2534 ast::UintTy::U128 => UintTy::U128,
2538 pub fn float_ty(fty: ast::FloatTy) -> FloatTy {
2540 ast::FloatTy::F32 => FloatTy::F32,
2541 ast::FloatTy::F64 => FloatTy::F64,
2545 pub fn ast_int_ty(ity: IntTy) -> ast::IntTy {
2547 IntTy::Isize => ast::IntTy::Isize,
2548 IntTy::I8 => ast::IntTy::I8,
2549 IntTy::I16 => ast::IntTy::I16,
2550 IntTy::I32 => ast::IntTy::I32,
2551 IntTy::I64 => ast::IntTy::I64,
2552 IntTy::I128 => ast::IntTy::I128,
2556 pub fn ast_uint_ty(uty: UintTy) -> ast::UintTy {
2558 UintTy::Usize => ast::UintTy::Usize,
2559 UintTy::U8 => ast::UintTy::U8,
2560 UintTy::U16 => ast::UintTy::U16,
2561 UintTy::U32 => ast::UintTy::U32,
2562 UintTy::U64 => ast::UintTy::U64,
2563 UintTy::U128 => ast::UintTy::U128,
2567 pub fn provide(providers: &mut ty::query::Providers) {
2568 closure::provide(providers);
2569 context::provide(providers);
2570 erase_regions::provide(providers);
2571 inhabitedness::provide(providers);
2572 util::provide(providers);
2573 print::provide(providers);
2574 super::util::bug::provide(providers);
2575 super::middle::provide(providers);
2576 *providers = ty::query::Providers {
2577 trait_impls_of: trait_def::trait_impls_of_provider,
2578 incoherent_impls: trait_def::incoherent_impls_provider,
2579 const_param_default: consts::const_param_default,
2580 vtable_allocation: vtable::vtable_allocation_provider,
2585 /// A map for the local crate mapping each type to a vector of its
2586 /// inherent impls. This is not meant to be used outside of coherence;
2587 /// rather, you should request the vector for a specific type via
2588 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2589 /// (constructing this map requires touching the entire crate).
2590 #[derive(Clone, Debug, Default, HashStable)]
2591 pub struct CrateInherentImpls {
2592 pub inherent_impls: LocalDefIdMap<Vec<DefId>>,
2593 pub incoherent_impls: FxHashMap<SimplifiedType, Vec<LocalDefId>>,
2596 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]
2597 pub struct SymbolName<'tcx> {
2598 /// `&str` gives a consistent ordering, which ensures reproducible builds.
2599 pub name: &'tcx str,
2602 impl<'tcx> SymbolName<'tcx> {
2603 pub fn new(tcx: TyCtxt<'tcx>, name: &str) -> SymbolName<'tcx> {
2605 name: unsafe { str::from_utf8_unchecked(tcx.arena.alloc_slice(name.as_bytes())) },
2610 impl<'tcx> fmt::Display for SymbolName<'tcx> {
2611 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2612 fmt::Display::fmt(&self.name, fmt)
2616 impl<'tcx> fmt::Debug for SymbolName<'tcx> {
2617 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2618 fmt::Display::fmt(&self.name, fmt)
2622 #[derive(Debug, Default, Copy, Clone)]
2623 pub struct InferVarInfo {
2624 /// This is true if we identified that this Ty (`?T`) is found in a `?T: Foo`
2625 /// obligation, where:
2627 /// * `Foo` is not `Sized`
2628 /// * `(): Foo` may be satisfied
2629 pub self_in_trait: bool,
2630 /// This is true if we identified that this Ty (`?T`) is found in a `<_ as
2631 /// _>::AssocType = ?T`
2635 /// The constituent parts of a type level constant of kind ADT or array.
2636 #[derive(Copy, Clone, Debug, HashStable)]
2637 pub struct DestructuredConst<'tcx> {
2638 pub variant: Option<VariantIdx>,
2639 pub fields: &'tcx [ty::Const<'tcx>],
2642 // Some types are used a lot. Make sure they don't unintentionally get bigger.
2643 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2646 use rustc_data_structures::static_assert_size;
2647 // tidy-alphabetical-start
2648 static_assert_size!(PredicateKind<'_>, 32);
2649 static_assert_size!(WithCachedTypeInfo<TyKind<'_>>, 56);
2650 // tidy-alphabetical-end