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 pub use self::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable};
13 pub use self::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
14 pub use self::AssocItemContainer::*;
15 pub use self::BorrowKind::*;
16 pub use self::IntVarValue::*;
17 pub use self::Variance::*;
18 use crate::error::{OpaqueHiddenTypeMismatch, TypeMismatchReason};
19 use crate::metadata::ModChild;
20 use crate::middle::privacy::EffectiveVisibilities;
21 use crate::mir::{Body, GeneratorLayout};
22 use crate::traits::{self, Reveal};
24 use crate::ty::fast_reject::SimplifiedType;
25 use crate::ty::util::Discr;
29 use hir::OpaqueTyOrigin;
31 use rustc_ast::node_id::NodeMap;
32 use rustc_attr as attr;
33 use rustc_data_structures::fingerprint::Fingerprint;
34 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
35 use rustc_data_structures::intern::{Interned, WithStableHash};
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, LocalDefId, LocalDefIdMap};
41 use rustc_hir::definitions::Definitions;
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::CrateStoreDyn;
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, VariantIdx};
56 use std::hash::{Hash, Hasher};
57 use std::marker::PhantomData;
59 use std::num::NonZeroUsize;
60 use std::ops::ControlFlow;
63 pub use crate::ty::diagnostics::*;
64 pub use rustc_type_ir::DynKind::*;
65 pub use rustc_type_ir::InferTy::*;
66 pub use rustc_type_ir::RegionKind::*;
67 pub use rustc_type_ir::TyKind::*;
68 pub use rustc_type_ir::*;
70 pub use self::binding::BindingMode;
71 pub use self::binding::BindingMode::*;
72 pub use self::closure::{
73 is_ancestor_or_same_capture, place_to_string_for_capture, BorrowKind, CaptureInfo,
74 CapturedPlace, ClosureKind, MinCaptureInformationMap, MinCaptureList,
75 RootVariableMinCaptureList, UpvarCapture, UpvarCaptureMap, UpvarId, UpvarListMap, UpvarPath,
78 pub use self::consts::{
79 Const, ConstInt, ConstKind, ConstS, InferConst, ScalarInt, UnevaluatedConst, ValTree,
81 pub use self::context::{
82 tls, CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
83 CtxtInterners, DeducedParamAttrs, FreeRegionInfo, GeneratorDiagnosticData,
84 GeneratorInteriorTypeCause, GlobalCtxt, Lift, OnDiskCache, TyCtxt, TypeckResults, UserType,
85 UserTypeAnnotationIndex,
87 pub use self::instance::{Instance, InstanceDef, ShortInstance};
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 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 ProjectionTy, Region, RegionKind, RegionVid, TraitRef, TyKind, TypeAndMut, UpvarSubsts,
102 pub use self::trait_def::TraitDef;
105 pub mod abstract_const;
114 pub mod inhabitedness;
116 pub mod normalize_erasing_regions;
141 mod structural_impls;
146 pub type RegisteredTools = FxHashSet<Ident>;
148 pub struct ResolverOutputs {
149 pub definitions: Definitions,
150 pub global_ctxt: ResolverGlobalCtxt,
151 pub ast_lowering: ResolverAstLowering,
155 pub struct ResolverGlobalCtxt {
156 pub cstore: Box<CrateStoreDyn>,
157 pub visibilities: FxHashMap<LocalDefId, Visibility>,
158 /// This field is used to decide whether we should make `PRIVATE_IN_PUBLIC` a hard error.
159 pub has_pub_restricted: bool,
160 /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
161 pub expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
162 /// Reference span for definitions.
163 pub source_span: IndexVec<LocalDefId, Span>,
164 pub effective_visibilities: EffectiveVisibilities,
165 pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
166 pub maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
167 pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
168 pub reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
169 pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
170 /// Extern prelude entries. The value is `true` if the entry was introduced
171 /// via `extern crate` item and not `--extern` option or compiler built-in.
172 pub extern_prelude: FxHashMap<Symbol, bool>,
173 pub main_def: Option<MainDefinition>,
174 pub trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
175 /// A list of proc macro LocalDefIds, written out in the order in which
176 /// they are declared in the static array generated by proc_macro_harness.
177 pub proc_macros: Vec<LocalDefId>,
178 /// Mapping from ident span to path span for paths that don't exist as written, but that
179 /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
180 pub confused_type_with_std_module: FxHashMap<Span, Span>,
181 pub registered_tools: RegisteredTools,
184 /// Resolutions that should only be used for lowering.
185 /// This struct is meant to be consumed by lowering.
187 pub struct ResolverAstLowering {
188 pub legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
190 /// Resolutions for nodes that have a single resolution.
191 pub partial_res_map: NodeMap<hir::def::PartialRes>,
192 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
193 pub import_res_map: NodeMap<hir::def::PerNS<Option<Res<ast::NodeId>>>>,
194 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
195 pub label_res_map: NodeMap<ast::NodeId>,
196 /// Resolutions for lifetimes.
197 pub lifetimes_res_map: NodeMap<LifetimeRes>,
198 /// Lifetime parameters that lowering will have to introduce.
199 pub extra_lifetime_params_map: NodeMap<Vec<(Ident, ast::NodeId, LifetimeRes)>>,
201 pub next_node_id: ast::NodeId,
203 pub node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
204 pub def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
206 pub trait_map: NodeMap<Vec<hir::TraitCandidate>>,
207 /// A small map keeping true kinds of built-in macros that appear to be fn-like on
208 /// the surface (`macro` items in libcore), but are actually attributes or derives.
209 pub builtin_macro_kinds: FxHashMap<LocalDefId, MacroKind>,
212 #[derive(Clone, Copy, Debug)]
213 pub struct MainDefinition {
214 pub res: Res<ast::NodeId>,
219 impl MainDefinition {
220 pub fn opt_fn_def_id(self) -> Option<DefId> {
221 if let Res::Def(DefKind::Fn, def_id) = self.res { Some(def_id) } else { None }
225 /// The "header" of an impl is everything outside the body: a Self type, a trait
226 /// ref (in the case of a trait impl), and a set of predicates (from the
227 /// bounds / where-clauses).
228 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
229 pub struct ImplHeader<'tcx> {
230 pub impl_def_id: DefId,
231 pub self_ty: Ty<'tcx>,
232 pub trait_ref: Option<TraitRef<'tcx>>,
233 pub predicates: Vec<Predicate<'tcx>>,
236 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
237 pub enum ImplSubject<'tcx> {
238 Trait(TraitRef<'tcx>),
242 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable, Debug)]
243 #[derive(TypeFoldable, TypeVisitable)]
244 pub enum ImplPolarity {
245 /// `impl Trait for Type`
247 /// `impl !Trait for Type`
249 /// `#[rustc_reservation_impl] impl Trait for Type`
251 /// This is a "stability hack", not a real Rust feature.
252 /// See #64631 for details.
257 /// Flips polarity by turning `Positive` into `Negative` and `Negative` into `Positive`.
258 pub fn flip(&self) -> Option<ImplPolarity> {
260 ImplPolarity::Positive => Some(ImplPolarity::Negative),
261 ImplPolarity::Negative => Some(ImplPolarity::Positive),
262 ImplPolarity::Reservation => None,
267 impl fmt::Display for ImplPolarity {
268 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
270 Self::Positive => f.write_str("positive"),
271 Self::Negative => f.write_str("negative"),
272 Self::Reservation => f.write_str("reservation"),
277 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, Encodable, Decodable, HashStable)]
278 pub enum Visibility<Id = LocalDefId> {
279 /// Visible everywhere (including in other crates).
281 /// Visible only in the given crate-local module.
285 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
286 pub enum BoundConstness {
289 /// `T: ~const Trait`
291 /// Requires resolving to const only when we are in a const context.
295 impl BoundConstness {
296 /// Reduce `self` and `constness` to two possible combined states instead of four.
297 pub fn and(&mut self, constness: hir::Constness) -> hir::Constness {
298 match (constness, self) {
299 (hir::Constness::Const, BoundConstness::ConstIfConst) => hir::Constness::Const,
301 *this = BoundConstness::NotConst;
302 hir::Constness::NotConst
308 impl fmt::Display for BoundConstness {
309 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
311 Self::NotConst => f.write_str("normal"),
312 Self::ConstIfConst => f.write_str("`~const`"),
317 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, TyEncodable, TyDecodable, HashStable)]
318 #[derive(TypeFoldable, TypeVisitable)]
319 pub struct ClosureSizeProfileData<'tcx> {
320 /// Tuple containing the types of closure captures before the feature `capture_disjoint_fields`
321 pub before_feature_tys: Ty<'tcx>,
322 /// Tuple containing the types of closure captures after the feature `capture_disjoint_fields`
323 pub after_feature_tys: Ty<'tcx>,
326 pub trait DefIdTree: Copy {
327 fn opt_parent(self, id: DefId) -> Option<DefId>;
331 fn parent(self, id: DefId) -> DefId {
332 match self.opt_parent(id) {
334 // not `unwrap_or_else` to avoid breaking caller tracking
335 None => bug!("{id:?} doesn't have a parent"),
341 fn opt_local_parent(self, id: LocalDefId) -> Option<LocalDefId> {
342 self.opt_parent(id.to_def_id()).map(DefId::expect_local)
347 fn local_parent(self, id: LocalDefId) -> LocalDefId {
348 self.parent(id.to_def_id()).expect_local()
351 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
352 if descendant.krate != ancestor.krate {
356 while descendant != ancestor {
357 match self.opt_parent(descendant) {
358 Some(parent) => descendant = parent,
359 None => return false,
366 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
368 fn opt_parent(self, id: DefId) -> Option<DefId> {
369 self.def_key(id).parent.map(|index| DefId { index, ..id })
373 impl<Id> Visibility<Id> {
374 pub fn is_public(self) -> bool {
375 matches!(self, Visibility::Public)
378 pub fn map_id<OutId>(self, f: impl FnOnce(Id) -> OutId) -> Visibility<OutId> {
380 Visibility::Public => Visibility::Public,
381 Visibility::Restricted(id) => Visibility::Restricted(f(id)),
386 impl<Id: Into<DefId>> Visibility<Id> {
387 pub fn to_def_id(self) -> Visibility<DefId> {
388 self.map_id(Into::into)
391 /// Returns `true` if an item with this visibility is accessible from the given module.
392 pub fn is_accessible_from(self, module: impl Into<DefId>, tree: impl DefIdTree) -> bool {
394 // Public items are visible everywhere.
395 Visibility::Public => true,
396 Visibility::Restricted(id) => tree.is_descendant_of(module.into(), id.into()),
400 /// Returns `true` if this visibility is at least as accessible as the given visibility
401 pub fn is_at_least(self, vis: Visibility<impl Into<DefId>>, tree: impl DefIdTree) -> bool {
403 Visibility::Public => self.is_public(),
404 Visibility::Restricted(id) => self.is_accessible_from(id, tree),
409 impl Visibility<DefId> {
410 pub fn expect_local(self) -> Visibility {
411 self.map_id(|id| id.expect_local())
414 // Returns `true` if this item is visible anywhere in the local crate.
415 pub fn is_visible_locally(self) -> bool {
417 Visibility::Public => true,
418 Visibility::Restricted(def_id) => def_id.is_local(),
423 /// The crate variances map is computed during typeck and contains the
424 /// variance of every item in the local crate. You should not use it
425 /// directly, because to do so will make your pass dependent on the
426 /// HIR of every item in the local crate. Instead, use
427 /// `tcx.variances_of()` to get the variance for a *particular*
429 #[derive(HashStable, Debug)]
430 pub struct CrateVariancesMap<'tcx> {
431 /// For each item with generics, maps to a vector of the variance
432 /// of its generics. If an item has no generics, it will have no
434 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
437 // Contains information needed to resolve types and (in the future) look up
438 // the types of AST nodes.
439 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
440 pub struct CReaderCacheKey {
441 pub cnum: Option<CrateNum>,
445 /// Represents a type.
448 /// - This is a very "dumb" struct (with no derives and no `impls`).
449 /// - Values of this type are always interned and thus unique, and are stored
450 /// as an `Interned<TyS>`.
451 /// - `Ty` (which contains a reference to a `Interned<TyS>`) or `Interned<TyS>`
452 /// should be used everywhere instead of `TyS`. In particular, `Ty` has most
453 /// of the relevant methods.
454 #[derive(PartialEq, Eq, PartialOrd, Ord)]
455 #[allow(rustc::usage_of_ty_tykind)]
456 pub(crate) struct TyS<'tcx> {
457 /// This field shouldn't be used directly and may be removed in the future.
458 /// Use `Ty::kind()` instead.
461 /// This field provides fast access to information that is also contained
464 /// This field shouldn't be used directly and may be removed in the future.
465 /// Use `Ty::flags()` instead.
468 /// This field provides fast access to information that is also contained
471 /// This is a kind of confusing thing: it stores the smallest
474 /// (a) the binder itself captures nothing but
475 /// (b) all the late-bound things within the type are captured
476 /// by some sub-binder.
478 /// So, for a type without any late-bound things, like `u32`, this
479 /// will be *innermost*, because that is the innermost binder that
480 /// captures nothing. But for a type `&'D u32`, where `'D` is a
481 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
482 /// -- the binder itself does not capture `D`, but `D` is captured
483 /// by an inner binder.
485 /// We call this concept an "exclusive" binder `D` because all
486 /// De Bruijn indices within the type are contained within `0..D`
488 outer_exclusive_binder: ty::DebruijnIndex,
491 /// Use this rather than `TyS`, whenever possible.
492 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)]
493 #[rustc_diagnostic_item = "Ty"]
494 #[rustc_pass_by_value]
495 pub struct Ty<'tcx>(Interned<'tcx, WithStableHash<TyS<'tcx>>>);
497 impl<'tcx> TyCtxt<'tcx> {
498 /// A "bool" type used in rustc_mir_transform unit tests when we
499 /// have not spun up a TyCtxt.
500 pub const BOOL_TY_FOR_UNIT_TESTING: Ty<'tcx> = Ty(Interned::new_unchecked(&WithStableHash {
503 flags: TypeFlags::empty(),
504 outer_exclusive_binder: DebruijnIndex::from_usize(0),
506 stable_hash: Fingerprint::ZERO,
510 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
512 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
516 // The other fields just provide fast access to information that is
517 // also contained in `kind`, so no need to hash them.
520 outer_exclusive_binder: _,
523 kind.hash_stable(hcx, hasher)
527 impl ty::EarlyBoundRegion {
528 /// Does this early bound region have a name? Early bound regions normally
529 /// always have names except when using anonymous lifetimes (`'_`).
530 pub fn has_name(&self) -> bool {
531 self.name != kw::UnderscoreLifetime
535 /// Represents a predicate.
537 /// See comments on `TyS`, which apply here too (albeit for
538 /// `PredicateS`/`Predicate` rather than `TyS`/`Ty`).
540 pub(crate) struct PredicateS<'tcx> {
541 kind: Binder<'tcx, PredicateKind<'tcx>>,
543 /// See the comment for the corresponding field of [TyS].
544 outer_exclusive_binder: ty::DebruijnIndex,
547 /// Use this rather than `PredicateS`, whenever possible.
548 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
549 #[rustc_pass_by_value]
550 pub struct Predicate<'tcx>(Interned<'tcx, PredicateS<'tcx>>);
552 impl<'tcx> Predicate<'tcx> {
553 /// Gets the inner `Binder<'tcx, PredicateKind<'tcx>>`.
555 pub fn kind(self) -> Binder<'tcx, PredicateKind<'tcx>> {
560 pub fn flags(self) -> TypeFlags {
565 pub fn outer_exclusive_binder(self) -> DebruijnIndex {
566 self.0.outer_exclusive_binder
569 /// Flips the polarity of a Predicate.
571 /// Given `T: Trait` predicate it returns `T: !Trait` and given `T: !Trait` returns `T: Trait`.
572 pub fn flip_polarity(self, tcx: TyCtxt<'tcx>) -> Option<Predicate<'tcx>> {
575 .map_bound(|kind| match kind {
576 PredicateKind::Trait(TraitPredicate { trait_ref, constness, polarity }) => {
577 Some(PredicateKind::Trait(TraitPredicate {
580 polarity: polarity.flip()?,
588 Some(tcx.mk_predicate(kind))
591 pub fn without_const(mut self, tcx: TyCtxt<'tcx>) -> Self {
592 if let PredicateKind::Trait(TraitPredicate { trait_ref, constness, polarity }) = self.kind().skip_binder()
593 && constness != BoundConstness::NotConst
595 self = tcx.mk_predicate(self.kind().rebind(PredicateKind::Trait(TraitPredicate {
597 constness: BoundConstness::NotConst,
604 /// Whether this projection can be soundly normalized.
606 /// Wf predicates must not be normalized, as normalization
607 /// can remove required bounds which would cause us to
608 /// unsoundly accept some programs. See #91068.
610 pub fn allow_normalization(self) -> bool {
611 match self.kind().skip_binder() {
612 PredicateKind::WellFormed(_) => false,
613 PredicateKind::Trait(_)
614 | PredicateKind::RegionOutlives(_)
615 | PredicateKind::TypeOutlives(_)
616 | PredicateKind::Projection(_)
617 | PredicateKind::ObjectSafe(_)
618 | PredicateKind::ClosureKind(_, _, _)
619 | PredicateKind::Subtype(_)
620 | PredicateKind::Coerce(_)
621 | PredicateKind::ConstEvaluatable(_)
622 | PredicateKind::ConstEquate(_, _)
623 | PredicateKind::Ambiguous
624 | PredicateKind::TypeWellFormedFromEnv(_) => true,
629 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {
630 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
634 // The other fields just provide fast access to information that is
635 // also contained in `kind`, so no need to hash them.
637 outer_exclusive_binder: _,
640 kind.hash_stable(hcx, hasher);
644 impl rustc_errors::IntoDiagnosticArg for Predicate<'_> {
645 fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
646 rustc_errors::DiagnosticArgValue::Str(std::borrow::Cow::Owned(self.to_string()))
650 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
651 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
652 pub enum PredicateKind<'tcx> {
653 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
654 /// the `Self` type of the trait reference and `A`, `B`, and `C`
655 /// would be the type parameters.
656 Trait(TraitPredicate<'tcx>),
659 RegionOutlives(RegionOutlivesPredicate<'tcx>),
662 TypeOutlives(TypeOutlivesPredicate<'tcx>),
664 /// `where <T as TraitRef>::Name == X`, approximately.
665 /// See the `ProjectionPredicate` struct for details.
666 Projection(ProjectionPredicate<'tcx>),
668 /// No syntax: `T` well-formed.
669 WellFormed(GenericArg<'tcx>),
671 /// Trait must be object-safe.
674 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
675 /// for some substitutions `...` and `T` being a closure type.
676 /// Satisfied (or refuted) once we know the closure's kind.
677 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
681 /// This obligation is created most often when we have two
682 /// unresolved type variables and hence don't have enough
683 /// information to process the subtyping obligation yet.
684 Subtype(SubtypePredicate<'tcx>),
686 /// `T1` coerced to `T2`
688 /// Like a subtyping obligation, this is created most often
689 /// when we have two unresolved type variables and hence
690 /// don't have enough information to process the coercion
691 /// obligation yet. At the moment, we actually process coercions
692 /// very much like subtyping and don't handle the full coercion
694 Coerce(CoercePredicate<'tcx>),
696 /// Constant initializer must evaluate successfully.
697 ConstEvaluatable(ty::Const<'tcx>),
699 /// Constants must be equal. The first component is the const that is expected.
700 ConstEquate(Const<'tcx>, Const<'tcx>),
702 /// Represents a type found in the environment that we can use for implied bounds.
704 /// Only used for Chalk.
705 TypeWellFormedFromEnv(Ty<'tcx>),
707 /// A marker predicate that is always ambiguous.
708 /// Used for coherence to mark opaque types as possibly equal to each other but ambiguous.
712 /// The crate outlives map is computed during typeck and contains the
713 /// outlives of every item in the local crate. You should not use it
714 /// directly, because to do so will make your pass dependent on the
715 /// HIR of every item in the local crate. Instead, use
716 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
718 #[derive(HashStable, Debug)]
719 pub struct CratePredicatesMap<'tcx> {
720 /// For each struct with outlive bounds, maps to a vector of the
721 /// predicate of its outlive bounds. If an item has no outlives
722 /// bounds, it will have no entry.
723 pub predicates: FxHashMap<DefId, &'tcx [(Predicate<'tcx>, Span)]>,
726 impl<'tcx> Predicate<'tcx> {
727 /// Performs a substitution suitable for going from a
728 /// poly-trait-ref to supertraits that must hold if that
729 /// poly-trait-ref holds. This is slightly different from a normal
730 /// substitution in terms of what happens with bound regions. See
731 /// lengthy comment below for details.
732 pub fn subst_supertrait(
735 trait_ref: &ty::PolyTraitRef<'tcx>,
736 ) -> Predicate<'tcx> {
737 // The interaction between HRTB and supertraits is not entirely
738 // obvious. Let me walk you (and myself) through an example.
740 // Let's start with an easy case. Consider two traits:
742 // trait Foo<'a>: Bar<'a,'a> { }
743 // trait Bar<'b,'c> { }
745 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
746 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
747 // knew that `Foo<'x>` (for any 'x) then we also know that
748 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
749 // normal substitution.
751 // In terms of why this is sound, the idea is that whenever there
752 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
753 // holds. So if there is an impl of `T:Foo<'a>` that applies to
754 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
757 // Another example to be careful of is this:
759 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
760 // trait Bar1<'b,'c> { }
762 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
763 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
764 // reason is similar to the previous example: any impl of
765 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
766 // basically we would want to collapse the bound lifetimes from
767 // the input (`trait_ref`) and the supertraits.
769 // To achieve this in practice is fairly straightforward. Let's
770 // consider the more complicated scenario:
772 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
773 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
774 // where both `'x` and `'b` would have a DB index of 1.
775 // The substitution from the input trait-ref is therefore going to be
776 // `'a => 'x` (where `'x` has a DB index of 1).
777 // - The supertrait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
778 // early-bound parameter and `'b' is a late-bound parameter with a
780 // - If we replace `'a` with `'x` from the input, it too will have
781 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
782 // just as we wanted.
784 // There is only one catch. If we just apply the substitution `'a
785 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
786 // adjust the DB index because we substituting into a binder (it
787 // tries to be so smart...) resulting in `for<'x> for<'b>
788 // Bar1<'x,'b>` (we have no syntax for this, so use your
789 // imagination). Basically the 'x will have DB index of 2 and 'b
790 // will have DB index of 1. Not quite what we want. So we apply
791 // the substitution to the *contents* of the trait reference,
792 // rather than the trait reference itself (put another way, the
793 // substitution code expects equal binding levels in the values
794 // from the substitution and the value being substituted into, and
795 // this trick achieves that).
797 // Working through the second example:
798 // trait_ref: for<'x> T: Foo1<'^0.0>; substs: [T, '^0.0]
799 // predicate: for<'b> Self: Bar1<'a, '^0.0>; substs: [Self, 'a, '^0.0]
800 // We want to end up with:
801 // for<'x, 'b> T: Bar1<'^0.0, '^0.1>
803 // 1) We must shift all bound vars in predicate by the length
804 // of trait ref's bound vars. So, we would end up with predicate like
805 // Self: Bar1<'a, '^0.1>
806 // 2) We can then apply the trait substs to this, ending up with
807 // T: Bar1<'^0.0, '^0.1>
808 // 3) Finally, to create the final bound vars, we concatenate the bound
809 // vars of the trait ref with those of the predicate:
811 let bound_pred = self.kind();
812 let pred_bound_vars = bound_pred.bound_vars();
813 let trait_bound_vars = trait_ref.bound_vars();
814 // 1) Self: Bar1<'a, '^0.0> -> Self: Bar1<'a, '^0.1>
816 tcx.shift_bound_var_indices(trait_bound_vars.len(), bound_pred.skip_binder());
817 // 2) Self: Bar1<'a, '^0.1> -> T: Bar1<'^0.0, '^0.1>
818 let new = EarlyBinder(shifted_pred).subst(tcx, trait_ref.skip_binder().substs);
819 // 3) ['x] + ['b] -> ['x, 'b]
821 tcx.mk_bound_variable_kinds(trait_bound_vars.iter().chain(pred_bound_vars));
822 tcx.reuse_or_mk_predicate(self, ty::Binder::bind_with_vars(new, bound_vars))
826 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
827 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
828 pub struct TraitPredicate<'tcx> {
829 pub trait_ref: TraitRef<'tcx>,
831 pub constness: BoundConstness,
833 /// If polarity is Positive: we are proving that the trait is implemented.
835 /// If polarity is Negative: we are proving that a negative impl of this trait
836 /// exists. (Note that coherence also checks whether negative impls of supertraits
837 /// exist via a series of predicates.)
839 /// If polarity is Reserved: that's a bug.
840 pub polarity: ImplPolarity,
843 pub type PolyTraitPredicate<'tcx> = ty::Binder<'tcx, TraitPredicate<'tcx>>;
845 impl<'tcx> TraitPredicate<'tcx> {
846 pub fn remap_constness(&mut self, param_env: &mut ParamEnv<'tcx>) {
847 *param_env = param_env.with_constness(self.constness.and(param_env.constness()))
850 /// Remap the constness of this predicate before emitting it for diagnostics.
851 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
852 // this is different to `remap_constness` that callees want to print this predicate
853 // in case of selection errors. `T: ~const Drop` bounds cannot end up here when the
854 // param_env is not const because it is always satisfied in non-const contexts.
855 if let hir::Constness::NotConst = param_env.constness() {
856 self.constness = ty::BoundConstness::NotConst;
860 pub fn with_self_type(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self {
861 Self { trait_ref: self.trait_ref.with_self_type(tcx, self_ty), ..self }
864 pub fn def_id(self) -> DefId {
865 self.trait_ref.def_id
868 pub fn self_ty(self) -> Ty<'tcx> {
869 self.trait_ref.self_ty()
873 pub fn is_const_if_const(self) -> bool {
874 self.constness == BoundConstness::ConstIfConst
877 pub fn is_constness_satisfied_by(self, constness: hir::Constness) -> bool {
878 match (self.constness, constness) {
879 (BoundConstness::NotConst, _)
880 | (BoundConstness::ConstIfConst, hir::Constness::Const) => true,
881 (BoundConstness::ConstIfConst, hir::Constness::NotConst) => false,
885 pub fn without_const(mut self) -> Self {
886 self.constness = BoundConstness::NotConst;
891 impl<'tcx> PolyTraitPredicate<'tcx> {
892 pub fn def_id(self) -> DefId {
893 // Ok to skip binder since trait `DefId` does not care about regions.
894 self.skip_binder().def_id()
897 pub fn self_ty(self) -> ty::Binder<'tcx, Ty<'tcx>> {
898 self.map_bound(|trait_ref| trait_ref.self_ty())
901 /// Remap the constness of this predicate before emitting it for diagnostics.
902 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
903 *self = self.map_bound(|mut p| {
904 p.remap_constness_diag(param_env);
910 pub fn is_const_if_const(self) -> bool {
911 self.skip_binder().is_const_if_const()
915 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
916 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
917 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
918 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
919 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
920 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<'tcx, RegionOutlivesPredicate<'tcx>>;
921 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<'tcx, TypeOutlivesPredicate<'tcx>>;
923 /// Encodes that `a` must be a subtype of `b`. The `a_is_expected` flag indicates
924 /// whether the `a` type is the type that we should label as "expected" when
925 /// presenting user diagnostics.
926 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
927 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
928 pub struct SubtypePredicate<'tcx> {
929 pub a_is_expected: bool,
933 pub type PolySubtypePredicate<'tcx> = ty::Binder<'tcx, SubtypePredicate<'tcx>>;
935 /// Encodes that we have to coerce *from* the `a` type to the `b` type.
936 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
937 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
938 pub struct CoercePredicate<'tcx> {
942 pub type PolyCoercePredicate<'tcx> = ty::Binder<'tcx, CoercePredicate<'tcx>>;
944 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
945 pub struct Term<'tcx> {
947 marker: PhantomData<(Ty<'tcx>, Const<'tcx>)>,
950 impl Debug for Term<'_> {
951 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
952 let data = if let Some(ty) = self.ty() {
953 format!("Term::Ty({:?})", ty)
954 } else if let Some(ct) = self.ct() {
955 format!("Term::Ct({:?})", ct)
963 impl<'tcx> From<Ty<'tcx>> for Term<'tcx> {
964 fn from(ty: Ty<'tcx>) -> Self {
965 TermKind::Ty(ty).pack()
969 impl<'tcx> From<Const<'tcx>> for Term<'tcx> {
970 fn from(c: Const<'tcx>) -> Self {
971 TermKind::Const(c).pack()
975 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Term<'tcx> {
976 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
977 self.unpack().hash_stable(hcx, hasher);
981 impl<'tcx> TypeFoldable<'tcx> for Term<'tcx> {
982 fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
983 Ok(self.unpack().try_fold_with(folder)?.pack())
987 impl<'tcx> TypeVisitable<'tcx> for Term<'tcx> {
988 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
989 self.unpack().visit_with(visitor)
993 impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for Term<'tcx> {
994 fn encode(&self, e: &mut E) {
995 self.unpack().encode(e)
999 impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for Term<'tcx> {
1000 fn decode(d: &mut D) -> Self {
1001 let res: TermKind<'tcx> = Decodable::decode(d);
1006 impl<'tcx> Term<'tcx> {
1008 pub fn unpack(self) -> TermKind<'tcx> {
1009 let ptr = self.ptr.get();
1010 // SAFETY: use of `Interned::new_unchecked` here is ok because these
1011 // pointers were originally created from `Interned` types in `pack()`,
1012 // and this is just going in the other direction.
1014 match ptr & TAG_MASK {
1015 TYPE_TAG => TermKind::Ty(Ty(Interned::new_unchecked(
1016 &*((ptr & !TAG_MASK) as *const WithStableHash<ty::TyS<'tcx>>),
1018 CONST_TAG => TermKind::Const(ty::Const(Interned::new_unchecked(
1019 &*((ptr & !TAG_MASK) as *const ty::ConstS<'tcx>),
1021 _ => core::intrinsics::unreachable(),
1026 pub fn ty(&self) -> Option<Ty<'tcx>> {
1027 if let TermKind::Ty(ty) = self.unpack() { Some(ty) } else { None }
1030 pub fn ct(&self) -> Option<Const<'tcx>> {
1031 if let TermKind::Const(c) = self.unpack() { Some(c) } else { None }
1034 pub fn into_arg(self) -> GenericArg<'tcx> {
1035 match self.unpack() {
1036 TermKind::Ty(ty) => ty.into(),
1037 TermKind::Const(c) => c.into(),
1042 const TAG_MASK: usize = 0b11;
1043 const TYPE_TAG: usize = 0b00;
1044 const CONST_TAG: usize = 0b01;
1046 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
1047 #[derive(HashStable, TypeFoldable, TypeVisitable)]
1048 pub enum TermKind<'tcx> {
1053 impl<'tcx> TermKind<'tcx> {
1055 fn pack(self) -> Term<'tcx> {
1056 let (tag, ptr) = match self {
1057 TermKind::Ty(ty) => {
1058 // Ensure we can use the tag bits.
1059 assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
1060 (TYPE_TAG, ty.0.0 as *const WithStableHash<ty::TyS<'tcx>> as usize)
1062 TermKind::Const(ct) => {
1063 // Ensure we can use the tag bits.
1064 assert_eq!(mem::align_of_val(&*ct.0.0) & TAG_MASK, 0);
1065 (CONST_TAG, ct.0.0 as *const ty::ConstS<'tcx> as usize)
1069 Term { ptr: unsafe { NonZeroUsize::new_unchecked(ptr | tag) }, marker: PhantomData }
1073 /// This kind of predicate has no *direct* correspondent in the
1074 /// syntax, but it roughly corresponds to the syntactic forms:
1076 /// 1. `T: TraitRef<..., Item = Type>`
1077 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1079 /// In particular, form #1 is "desugared" to the combination of a
1080 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1081 /// predicates. Form #2 is a broader form in that it also permits
1082 /// equality between arbitrary types. Processing an instance of
1083 /// Form #2 eventually yields one of these `ProjectionPredicate`
1084 /// instances to normalize the LHS.
1085 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
1086 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
1087 pub struct ProjectionPredicate<'tcx> {
1088 pub projection_ty: ProjectionTy<'tcx>,
1089 pub term: Term<'tcx>,
1092 pub type PolyProjectionPredicate<'tcx> = Binder<'tcx, ProjectionPredicate<'tcx>>;
1094 impl<'tcx> PolyProjectionPredicate<'tcx> {
1095 /// Returns the `DefId` of the trait of the associated item being projected.
1097 pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
1098 self.skip_binder().projection_ty.trait_def_id(tcx)
1101 /// Get the [PolyTraitRef] required for this projection to be well formed.
1102 /// Note that for generic associated types the predicates of the associated
1103 /// type also need to be checked.
1105 pub fn required_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
1106 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1107 // `self.0.trait_ref` is permitted to have escaping regions.
1108 // This is because here `self` has a `Binder` and so does our
1109 // return value, so we are preserving the number of binding
1111 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1114 pub fn term(&self) -> Binder<'tcx, Term<'tcx>> {
1115 self.map_bound(|predicate| predicate.term)
1118 /// The `DefId` of the `TraitItem` for the associated type.
1120 /// Note that this is not the `DefId` of the `TraitRef` containing this
1121 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1122 pub fn projection_def_id(&self) -> DefId {
1123 // Ok to skip binder since trait `DefId` does not care about regions.
1124 self.skip_binder().projection_ty.item_def_id
1128 pub trait ToPolyTraitRef<'tcx> {
1129 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1132 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1133 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1134 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1138 pub trait ToPredicate<'tcx, Predicate> {
1139 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate;
1142 impl<'tcx, T> ToPredicate<'tcx, T> for T {
1143 fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T {
1148 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for Binder<'tcx, PredicateKind<'tcx>> {
1150 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1151 tcx.mk_predicate(self)
1155 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyTraitPredicate<'tcx> {
1156 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1157 self.map_bound(PredicateKind::Trait).to_predicate(tcx)
1161 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyRegionOutlivesPredicate<'tcx> {
1162 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1163 self.map_bound(PredicateKind::RegionOutlives).to_predicate(tcx)
1167 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyTypeOutlivesPredicate<'tcx> {
1168 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1169 self.map_bound(PredicateKind::TypeOutlives).to_predicate(tcx)
1173 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyProjectionPredicate<'tcx> {
1174 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1175 self.map_bound(PredicateKind::Projection).to_predicate(tcx)
1179 impl<'tcx> Predicate<'tcx> {
1180 pub fn to_opt_poly_trait_pred(self) -> Option<PolyTraitPredicate<'tcx>> {
1181 let predicate = self.kind();
1182 match predicate.skip_binder() {
1183 PredicateKind::Trait(t) => Some(predicate.rebind(t)),
1184 PredicateKind::Projection(..)
1185 | PredicateKind::Subtype(..)
1186 | PredicateKind::Coerce(..)
1187 | PredicateKind::RegionOutlives(..)
1188 | PredicateKind::WellFormed(..)
1189 | PredicateKind::ObjectSafe(..)
1190 | PredicateKind::ClosureKind(..)
1191 | PredicateKind::TypeOutlives(..)
1192 | PredicateKind::ConstEvaluatable(..)
1193 | PredicateKind::ConstEquate(..)
1194 | PredicateKind::Ambiguous
1195 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1199 pub fn to_opt_poly_projection_pred(self) -> Option<PolyProjectionPredicate<'tcx>> {
1200 let predicate = self.kind();
1201 match predicate.skip_binder() {
1202 PredicateKind::Projection(t) => Some(predicate.rebind(t)),
1203 PredicateKind::Trait(..)
1204 | PredicateKind::Subtype(..)
1205 | PredicateKind::Coerce(..)
1206 | PredicateKind::RegionOutlives(..)
1207 | PredicateKind::WellFormed(..)
1208 | PredicateKind::ObjectSafe(..)
1209 | PredicateKind::ClosureKind(..)
1210 | PredicateKind::TypeOutlives(..)
1211 | PredicateKind::ConstEvaluatable(..)
1212 | PredicateKind::ConstEquate(..)
1213 | PredicateKind::Ambiguous
1214 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1218 pub fn to_opt_type_outlives(self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1219 let predicate = self.kind();
1220 match predicate.skip_binder() {
1221 PredicateKind::TypeOutlives(data) => Some(predicate.rebind(data)),
1222 PredicateKind::Trait(..)
1223 | PredicateKind::Projection(..)
1224 | PredicateKind::Subtype(..)
1225 | PredicateKind::Coerce(..)
1226 | PredicateKind::RegionOutlives(..)
1227 | PredicateKind::WellFormed(..)
1228 | PredicateKind::ObjectSafe(..)
1229 | PredicateKind::ClosureKind(..)
1230 | PredicateKind::ConstEvaluatable(..)
1231 | PredicateKind::ConstEquate(..)
1232 | PredicateKind::Ambiguous
1233 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1238 /// Represents the bounds declared on a particular set of type
1239 /// parameters. Should eventually be generalized into a flag list of
1240 /// where-clauses. You can obtain an `InstantiatedPredicates` list from a
1241 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1242 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1243 /// the `GenericPredicates` are expressed in terms of the bound type
1244 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1245 /// represented a set of bounds for some particular instantiation,
1246 /// meaning that the generic parameters have been substituted with
1250 /// ```ignore (illustrative)
1251 /// struct Foo<T, U: Bar<T>> { ... }
1253 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1254 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1255 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1256 /// [usize:Bar<isize>]]`.
1257 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
1258 pub struct InstantiatedPredicates<'tcx> {
1259 pub predicates: Vec<Predicate<'tcx>>,
1260 pub spans: Vec<Span>,
1263 impl<'tcx> InstantiatedPredicates<'tcx> {
1264 pub fn empty() -> InstantiatedPredicates<'tcx> {
1265 InstantiatedPredicates { predicates: vec![], spans: vec![] }
1268 pub fn is_empty(&self) -> bool {
1269 self.predicates.is_empty()
1273 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable, Lift)]
1274 #[derive(TypeFoldable, TypeVisitable)]
1275 pub struct OpaqueTypeKey<'tcx> {
1276 pub def_id: LocalDefId,
1277 pub substs: SubstsRef<'tcx>,
1280 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
1281 pub struct OpaqueHiddenType<'tcx> {
1282 /// The span of this particular definition of the opaque type. So
1285 /// ```ignore (incomplete snippet)
1286 /// type Foo = impl Baz;
1287 /// fn bar() -> Foo {
1288 /// // ^^^ This is the span we are looking for!
1292 /// In cases where the fn returns `(impl Trait, impl Trait)` or
1293 /// other such combinations, the result is currently
1294 /// over-approximated, but better than nothing.
1297 /// The type variable that represents the value of the opaque type
1298 /// that we require. In other words, after we compile this function,
1299 /// we will be created a constraint like:
1300 /// ```ignore (pseudo-rust)
1303 /// where `?C` is the value of this type variable. =) It may
1304 /// naturally refer to the type and lifetime parameters in scope
1305 /// in this function, though ultimately it should only reference
1306 /// those that are arguments to `Foo` in the constraint above. (In
1307 /// other words, `?C` should not include `'b`, even though it's a
1308 /// lifetime parameter on `foo`.)
1312 impl<'tcx> OpaqueHiddenType<'tcx> {
1313 pub fn report_mismatch(&self, other: &Self, tcx: TyCtxt<'tcx>) {
1314 // Found different concrete types for the opaque type.
1315 let sub_diag = if self.span == other.span {
1316 TypeMismatchReason::ConflictType { span: self.span }
1318 TypeMismatchReason::PreviousUse { span: self.span }
1320 tcx.sess.emit_err(OpaqueHiddenTypeMismatch {
1323 other_span: other.span,
1328 #[instrument(level = "debug", skip(tcx), ret)]
1329 pub fn remap_generic_params_to_declaration_params(
1331 opaque_type_key: OpaqueTypeKey<'tcx>,
1333 // typeck errors have subpar spans for opaque types, so delay error reporting until borrowck.
1334 ignore_errors: bool,
1335 origin: OpaqueTyOrigin,
1337 let OpaqueTypeKey { def_id, substs } = opaque_type_key;
1339 // Use substs to build up a reverse map from regions to their
1340 // identity mappings. This is necessary because of `impl
1341 // Trait` lifetimes are computed by replacing existing
1342 // lifetimes with 'static and remapping only those used in the
1343 // `impl Trait` return type, resulting in the parameters
1345 let id_substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
1348 // This zip may have several times the same lifetime in `substs` paired with a different
1349 // lifetime from `id_substs`. Simply `collect`ing the iterator is the correct behaviour:
1350 // it will pick the last one, which is the one we introduced in the impl-trait desugaring.
1351 let map = substs.iter().zip(id_substs);
1353 let map: FxHashMap<GenericArg<'tcx>, GenericArg<'tcx>> = match origin {
1354 // HACK: The HIR lowering for async fn does not generate
1355 // any `+ Captures<'x>` bounds for the `impl Future<...>`, so all async fns with lifetimes
1356 // would now fail to compile. We should probably just make hir lowering fill this in properly.
1357 OpaqueTyOrigin::AsyncFn(_) => map.collect(),
1358 OpaqueTyOrigin::FnReturn(_) | OpaqueTyOrigin::TyAlias => {
1359 // Opaque types may only use regions that are bound. So for
1361 // type Foo<'a, 'b, 'c> = impl Trait<'a> + 'b;
1363 // we may not use `'c` in the hidden type.
1364 let variances = tcx.variances_of(def_id);
1367 map.filter(|(_, v)| {
1368 let ty::GenericArgKind::Lifetime(lt) = v.unpack() else { return true };
1369 let ty::ReEarlyBound(ebr) = lt.kind() else { bug!() };
1370 variances[ebr.index as usize] == ty::Variance::Invariant
1375 debug!("map = {:#?}", map);
1377 // Convert the type from the function into a type valid outside
1378 // the function, by replacing invalid regions with 'static,
1379 // after producing an error for each of them.
1380 self.fold_with(&mut opaque_types::ReverseMapper::new(tcx, map, self.span, ignore_errors))
1384 /// The "placeholder index" fully defines a placeholder region, type, or const. Placeholders are
1385 /// identified by both a universe, as well as a name residing within that universe. Distinct bound
1386 /// regions/types/consts within the same universe simply have an unknown relationship to one
1388 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
1389 #[derive(HashStable, TyEncodable, TyDecodable)]
1390 pub struct Placeholder<T> {
1391 pub universe: UniverseIndex,
1395 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
1397 pub type PlaceholderType = Placeholder<BoundVar>;
1399 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1400 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]
1401 pub struct BoundConst<'tcx> {
1406 pub type PlaceholderConst<'tcx> = Placeholder<BoundVar>;
1408 /// A `DefId` which, in case it is a const argument, is potentially bundled with
1409 /// the `DefId` of the generic parameter it instantiates.
1411 /// This is used to avoid calls to `type_of` for const arguments during typeck
1412 /// which cause cycle errors.
1417 /// fn foo<const N: usize>(&self) -> [u8; N] { [0; N] }
1418 /// // ^ const parameter
1422 /// fn foo<const M: u8>(&self) -> usize { 42 }
1423 /// // ^ const parameter
1428 /// let _b = a.foo::<{ 3 + 7 }>();
1429 /// // ^^^^^^^^^ const argument
1433 /// Let's look at the call `a.foo::<{ 3 + 7 }>()` here. We do not know
1434 /// which `foo` is used until we know the type of `a`.
1436 /// We only know the type of `a` once we are inside of `typeck(main)`.
1437 /// We also end up normalizing the type of `_b` during `typeck(main)` which
1438 /// requires us to evaluate the const argument.
1440 /// To evaluate that const argument we need to know its type,
1441 /// which we would get using `type_of(const_arg)`. This requires us to
1442 /// resolve `foo` as it can be either `usize` or `u8` in this example.
1443 /// However, resolving `foo` once again requires `typeck(main)` to get the type of `a`,
1444 /// which results in a cycle.
1446 /// In short we must not call `type_of(const_arg)` during `typeck(main)`.
1448 /// When first creating the `ty::Const` of the const argument inside of `typeck` we have
1449 /// already resolved `foo` so we know which const parameter this argument instantiates.
1450 /// This means that we also know the expected result of `type_of(const_arg)` even if we
1451 /// aren't allowed to call that query: it is equal to `type_of(const_param)` which is
1452 /// trivial to compute.
1454 /// If we now want to use that constant in a place which potentially needs its type
1455 /// we also pass the type of its `const_param`. This is the point of `WithOptConstParam`,
1456 /// except that instead of a `Ty` we bundle the `DefId` of the const parameter.
1457 /// Meaning that we need to use `type_of(const_param_did)` if `const_param_did` is `Some`
1458 /// to get the type of `did`.
1459 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift, TyEncodable, TyDecodable)]
1460 #[derive(PartialEq, Eq, PartialOrd, Ord)]
1461 #[derive(Hash, HashStable)]
1462 pub struct WithOptConstParam<T> {
1464 /// The `DefId` of the corresponding generic parameter in case `did` is
1465 /// a const argument.
1467 /// Note that even if `did` is a const argument, this may still be `None`.
1468 /// All queries taking `WithOptConstParam` start by calling `tcx.opt_const_param_of(def.did)`
1469 /// to potentially update `param_did` in the case it is `None`.
1470 pub const_param_did: Option<DefId>,
1473 impl<T> WithOptConstParam<T> {
1474 /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`.
1476 pub fn unknown(did: T) -> WithOptConstParam<T> {
1477 WithOptConstParam { did, const_param_did: None }
1481 impl WithOptConstParam<LocalDefId> {
1482 /// Returns `Some((did, param_did))` if `def_id` is a const argument,
1483 /// `None` otherwise.
1485 pub fn try_lookup(did: LocalDefId, tcx: TyCtxt<'_>) -> Option<(LocalDefId, DefId)> {
1486 tcx.opt_const_param_of(did).map(|param_did| (did, param_did))
1489 /// In case `self` is unknown but `self.did` is a const argument, this returns
1490 /// a `WithOptConstParam` with the correct `const_param_did`.
1492 pub fn try_upgrade(self, tcx: TyCtxt<'_>) -> Option<WithOptConstParam<LocalDefId>> {
1493 if self.const_param_did.is_none() {
1494 if let const_param_did @ Some(_) = tcx.opt_const_param_of(self.did) {
1495 return Some(WithOptConstParam { did: self.did, const_param_did });
1502 pub fn to_global(self) -> WithOptConstParam<DefId> {
1503 WithOptConstParam { did: self.did.to_def_id(), const_param_did: self.const_param_did }
1506 pub fn def_id_for_type_of(self) -> DefId {
1507 if let Some(did) = self.const_param_did { did } else { self.did.to_def_id() }
1511 impl WithOptConstParam<DefId> {
1512 pub fn as_local(self) -> Option<WithOptConstParam<LocalDefId>> {
1515 .map(|did| WithOptConstParam { did, const_param_did: self.const_param_did })
1518 pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)> {
1519 if let Some(param_did) = self.const_param_did {
1520 if let Some(did) = self.did.as_local() {
1521 return Some((did, param_did));
1528 pub fn is_local(self) -> bool {
1532 pub fn def_id_for_type_of(self) -> DefId {
1533 self.const_param_did.unwrap_or(self.did)
1537 /// When type checking, we use the `ParamEnv` to track
1538 /// details about the set of where-clauses that are in scope at this
1539 /// particular point.
1540 #[derive(Copy, Clone, Hash, PartialEq, Eq)]
1541 pub struct ParamEnv<'tcx> {
1542 /// This packs both caller bounds and the reveal enum into one pointer.
1544 /// Caller bounds are `Obligation`s that the caller must satisfy. This is
1545 /// basically the set of bounds on the in-scope type parameters, translated
1546 /// into `Obligation`s, and elaborated and normalized.
1548 /// Use the `caller_bounds()` method to access.
1550 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1551 /// want `Reveal::All`.
1553 /// Note: This is packed, use the reveal() method to access it.
1554 packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, ParamTag, true>,
1557 #[derive(Copy, Clone)]
1559 reveal: traits::Reveal,
1560 constness: hir::Constness,
1563 unsafe impl rustc_data_structures::tagged_ptr::Tag for ParamTag {
1564 const BITS: usize = 2;
1566 fn into_usize(self) -> usize {
1568 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst } => 0,
1569 Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst } => 1,
1570 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const } => 2,
1571 Self { reveal: traits::Reveal::All, constness: hir::Constness::Const } => 3,
1575 unsafe fn from_usize(ptr: usize) -> Self {
1577 0 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst },
1578 1 => Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst },
1579 2 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const },
1580 3 => Self { reveal: traits::Reveal::All, constness: hir::Constness::Const },
1581 _ => std::hint::unreachable_unchecked(),
1586 impl<'tcx> fmt::Debug for ParamEnv<'tcx> {
1587 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1588 f.debug_struct("ParamEnv")
1589 .field("caller_bounds", &self.caller_bounds())
1590 .field("reveal", &self.reveal())
1591 .field("constness", &self.constness())
1596 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx> {
1597 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1598 self.caller_bounds().hash_stable(hcx, hasher);
1599 self.reveal().hash_stable(hcx, hasher);
1600 self.constness().hash_stable(hcx, hasher);
1604 impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
1605 fn try_fold_with<F: ty::fold::FallibleTypeFolder<'tcx>>(
1608 ) -> Result<Self, F::Error> {
1610 self.caller_bounds().try_fold_with(folder)?,
1611 self.reveal().try_fold_with(folder)?,
1617 impl<'tcx> TypeVisitable<'tcx> for ParamEnv<'tcx> {
1618 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
1619 self.caller_bounds().visit_with(visitor)?;
1620 self.reveal().visit_with(visitor)
1624 impl<'tcx> ParamEnv<'tcx> {
1625 /// Construct a trait environment suitable for contexts where
1626 /// there are no where-clauses in scope. Hidden types (like `impl
1627 /// Trait`) are left hidden, so this is suitable for ordinary
1630 pub fn empty() -> Self {
1631 Self::new(List::empty(), Reveal::UserFacing, hir::Constness::NotConst)
1635 pub fn caller_bounds(self) -> &'tcx List<Predicate<'tcx>> {
1636 self.packed.pointer()
1640 pub fn reveal(self) -> traits::Reveal {
1641 self.packed.tag().reveal
1645 pub fn constness(self) -> hir::Constness {
1646 self.packed.tag().constness
1650 pub fn is_const(self) -> bool {
1651 self.packed.tag().constness == hir::Constness::Const
1654 /// Construct a trait environment with no where-clauses in scope
1655 /// where the values of all `impl Trait` and other hidden types
1656 /// are revealed. This is suitable for monomorphized, post-typeck
1657 /// environments like codegen or doing optimizations.
1659 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1660 /// or invoke `param_env.with_reveal_all()`.
1662 pub fn reveal_all() -> Self {
1663 Self::new(List::empty(), Reveal::All, hir::Constness::NotConst)
1666 /// Construct a trait environment with the given set of predicates.
1669 caller_bounds: &'tcx List<Predicate<'tcx>>,
1671 constness: hir::Constness,
1673 ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, ParamTag { reveal, constness }) }
1676 pub fn with_user_facing(mut self) -> Self {
1677 self.packed.set_tag(ParamTag { reveal: Reveal::UserFacing, ..self.packed.tag() });
1682 pub fn with_constness(mut self, constness: hir::Constness) -> Self {
1683 self.packed.set_tag(ParamTag { constness, ..self.packed.tag() });
1688 pub fn with_const(mut self) -> Self {
1689 self.packed.set_tag(ParamTag { constness: hir::Constness::Const, ..self.packed.tag() });
1694 pub fn without_const(mut self) -> Self {
1695 self.packed.set_tag(ParamTag { constness: hir::Constness::NotConst, ..self.packed.tag() });
1700 pub fn remap_constness_with(&mut self, mut constness: ty::BoundConstness) {
1701 *self = self.with_constness(constness.and(self.constness()))
1704 /// Returns a new parameter environment with the same clauses, but
1705 /// which "reveals" the true results of projections in all cases
1706 /// (even for associated types that are specializable). This is
1707 /// the desired behavior during codegen and certain other special
1708 /// contexts; normally though we want to use `Reveal::UserFacing`,
1709 /// which is the default.
1710 /// All opaque types in the caller_bounds of the `ParamEnv`
1711 /// will be normalized to their underlying types.
1712 /// See PR #65989 and issue #65918 for more details
1713 pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self {
1714 if self.packed.tag().reveal == traits::Reveal::All {
1719 tcx.normalize_opaque_types(self.caller_bounds()),
1725 /// Returns this same environment but with no caller bounds.
1727 pub fn without_caller_bounds(self) -> Self {
1728 Self::new(List::empty(), self.reveal(), self.constness())
1731 /// Creates a suitable environment in which to perform trait
1732 /// queries on the given value. When type-checking, this is simply
1733 /// the pair of the environment plus value. But when reveal is set to
1734 /// All, then if `value` does not reference any type parameters, we will
1735 /// pair it with the empty environment. This improves caching and is generally
1738 /// N.B., we preserve the environment when type-checking because it
1739 /// is possible for the user to have wacky where-clauses like
1740 /// `where Box<u32>: Copy`, which are clearly never
1741 /// satisfiable. We generally want to behave as if they were true,
1742 /// although the surrounding function is never reachable.
1743 pub fn and<T: TypeVisitable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1744 match self.reveal() {
1745 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1748 if value.is_global() {
1749 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1751 ParamEnvAnd { param_env: self, value }
1758 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
1759 // the constness of trait bounds is being propagated correctly.
1760 impl<'tcx> PolyTraitRef<'tcx> {
1762 pub fn with_constness(self, constness: BoundConstness) -> PolyTraitPredicate<'tcx> {
1763 self.map_bound(|trait_ref| ty::TraitPredicate {
1766 polarity: ty::ImplPolarity::Positive,
1771 pub fn without_const(self) -> PolyTraitPredicate<'tcx> {
1772 self.with_constness(BoundConstness::NotConst)
1776 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
1777 #[derive(HashStable, Lift)]
1778 pub struct ParamEnvAnd<'tcx, T> {
1779 pub param_env: ParamEnv<'tcx>,
1783 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1784 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1785 (self.param_env, self.value)
1789 pub fn without_const(mut self) -> Self {
1790 self.param_env = self.param_env.without_const();
1795 #[derive(Copy, Clone, Debug, HashStable, Encodable, Decodable)]
1796 pub struct Destructor {
1797 /// The `DefId` of the destructor method
1799 /// The constness of the destructor method
1800 pub constness: hir::Constness,
1804 #[derive(HashStable, TyEncodable, TyDecodable)]
1805 pub struct VariantFlags: u32 {
1806 const NO_VARIANT_FLAGS = 0;
1807 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1808 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1809 /// Indicates whether this variant was obtained as part of recovering from
1810 /// a syntactic error. May be incomplete or bogus.
1811 const IS_RECOVERED = 1 << 1;
1815 /// Definition of a variant -- a struct's fields or an enum variant.
1816 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
1817 pub struct VariantDef {
1818 /// `DefId` that identifies the variant itself.
1819 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1821 /// `DefId` that identifies the variant's constructor.
1822 /// If this variant is a struct variant, then this is `None`.
1823 pub ctor: Option<(CtorKind, DefId)>,
1824 /// Variant or struct name.
1826 /// Discriminant of this variant.
1827 pub discr: VariantDiscr,
1828 /// Fields of this variant.
1829 pub fields: Vec<FieldDef>,
1830 /// Flags of the variant (e.g. is field list non-exhaustive)?
1831 flags: VariantFlags,
1835 /// Creates a new `VariantDef`.
1837 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1838 /// represents an enum variant).
1840 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1841 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1843 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1844 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1845 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1846 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1847 /// built-in trait), and we do not want to load attributes twice.
1849 /// If someone speeds up attribute loading to not be a performance concern, they can
1850 /// remove this hack and use the constructor `DefId` everywhere.
1853 variant_did: Option<DefId>,
1854 ctor: Option<(CtorKind, DefId)>,
1855 discr: VariantDiscr,
1856 fields: Vec<FieldDef>,
1860 is_field_list_non_exhaustive: bool,
1863 "VariantDef::new(name = {:?}, variant_did = {:?}, ctor = {:?}, discr = {:?},
1864 fields = {:?}, adt_kind = {:?}, parent_did = {:?})",
1865 name, variant_did, ctor, discr, fields, adt_kind, parent_did,
1868 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1869 if is_field_list_non_exhaustive {
1870 flags |= VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1874 flags |= VariantFlags::IS_RECOVERED;
1877 VariantDef { def_id: variant_did.unwrap_or(parent_did), ctor, name, discr, fields, flags }
1880 /// Is this field list non-exhaustive?
1882 pub fn is_field_list_non_exhaustive(&self) -> bool {
1883 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1886 /// Was this variant obtained as part of recovering from a syntactic error?
1888 pub fn is_recovered(&self) -> bool {
1889 self.flags.intersects(VariantFlags::IS_RECOVERED)
1892 /// Computes the `Ident` of this variant by looking up the `Span`
1893 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
1894 Ident::new(self.name, tcx.def_ident_span(self.def_id).unwrap())
1898 pub fn ctor_kind(&self) -> Option<CtorKind> {
1899 self.ctor.map(|(kind, _)| kind)
1903 pub fn ctor_def_id(&self) -> Option<DefId> {
1904 self.ctor.map(|(_, def_id)| def_id)
1908 impl PartialEq for VariantDef {
1910 fn eq(&self, other: &Self) -> bool {
1911 // There should be only one `VariantDef` for each `def_id`, therefore
1912 // it is fine to implement `PartialEq` only based on `def_id`.
1914 // Below, we exhaustively destructure `self` and `other` so that if the
1915 // definition of `VariantDef` changes, a compile-error will be produced,
1916 // reminding us to revisit this assumption.
1918 let Self { def_id: lhs_def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = &self;
1919 let Self { def_id: rhs_def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = other;
1920 lhs_def_id == rhs_def_id
1924 impl Eq for VariantDef {}
1926 impl Hash for VariantDef {
1928 fn hash<H: Hasher>(&self, s: &mut H) {
1929 // There should be only one `VariantDef` for each `def_id`, therefore
1930 // it is fine to implement `Hash` only based on `def_id`.
1932 // Below, we exhaustively destructure `self` so that if the definition
1933 // of `VariantDef` changes, a compile-error will be produced, reminding
1934 // us to revisit this assumption.
1936 let Self { def_id, ctor: _, name: _, discr: _, fields: _, flags: _ } = &self;
1941 #[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
1942 pub enum VariantDiscr {
1943 /// Explicit value for this variant, i.e., `X = 123`.
1944 /// The `DefId` corresponds to the embedded constant.
1947 /// The previous variant's discriminant plus one.
1948 /// For efficiency reasons, the distance from the
1949 /// last `Explicit` discriminant is being stored,
1950 /// or `0` for the first variant, if it has none.
1954 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
1955 pub struct FieldDef {
1958 pub vis: Visibility<DefId>,
1961 impl PartialEq for FieldDef {
1963 fn eq(&self, other: &Self) -> bool {
1964 // There should be only one `FieldDef` for each `did`, therefore it is
1965 // fine to implement `PartialEq` only based on `did`.
1967 // Below, we exhaustively destructure `self` so that if the definition
1968 // of `FieldDef` changes, a compile-error will be produced, reminding
1969 // us to revisit this assumption.
1971 let Self { did: lhs_did, name: _, vis: _ } = &self;
1973 let Self { did: rhs_did, name: _, vis: _ } = other;
1979 impl Eq for FieldDef {}
1981 impl Hash for FieldDef {
1983 fn hash<H: Hasher>(&self, s: &mut H) {
1984 // There should be only one `FieldDef` for each `did`, therefore it is
1985 // fine to implement `Hash` only based on `did`.
1987 // Below, we exhaustively destructure `self` so that if the definition
1988 // of `FieldDef` changes, a compile-error will be produced, reminding
1989 // us to revisit this assumption.
1991 let Self { did, name: _, vis: _ } = &self;
1998 #[derive(TyEncodable, TyDecodable, Default, HashStable)]
1999 pub struct ReprFlags: u8 {
2000 const IS_C = 1 << 0;
2001 const IS_SIMD = 1 << 1;
2002 const IS_TRANSPARENT = 1 << 2;
2003 // Internal only for now. If true, don't reorder fields.
2004 const IS_LINEAR = 1 << 3;
2005 // If true, the type's layout can be randomized using
2006 // the seed stored in `ReprOptions.layout_seed`
2007 const RANDOMIZE_LAYOUT = 1 << 4;
2008 // Any of these flags being set prevent field reordering optimisation.
2009 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits
2010 | ReprFlags::IS_SIMD.bits
2011 | ReprFlags::IS_LINEAR.bits;
2015 /// Represents the repr options provided by the user,
2016 #[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Default, HashStable)]
2017 pub struct ReprOptions {
2018 pub int: Option<attr::IntType>,
2019 pub align: Option<Align>,
2020 pub pack: Option<Align>,
2021 pub flags: ReprFlags,
2022 /// The seed to be used for randomizing a type's layout
2024 /// Note: This could technically be a `[u8; 16]` (a `u128`) which would
2025 /// be the "most accurate" hash as it'd encompass the item and crate
2026 /// hash without loss, but it does pay the price of being larger.
2027 /// Everything's a tradeoff, a `u64` seed should be sufficient for our
2028 /// purposes (primarily `-Z randomize-layout`)
2029 pub field_shuffle_seed: u64,
2033 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2034 let mut flags = ReprFlags::empty();
2035 let mut size = None;
2036 let mut max_align: Option<Align> = None;
2037 let mut min_pack: Option<Align> = None;
2039 // Generate a deterministically-derived seed from the item's path hash
2040 // to allow for cross-crate compilation to actually work
2041 let mut field_shuffle_seed = tcx.def_path_hash(did).0.to_smaller_hash();
2043 // If the user defined a custom seed for layout randomization, xor the item's
2044 // path hash with the user defined seed, this will allowing determinism while
2045 // still allowing users to further randomize layout generation for e.g. fuzzing
2046 if let Some(user_seed) = tcx.sess.opts.unstable_opts.layout_seed {
2047 field_shuffle_seed ^= user_seed;
2050 for attr in tcx.get_attrs(did, sym::repr) {
2051 for r in attr::parse_repr_attr(&tcx.sess, attr) {
2052 flags.insert(match r {
2053 attr::ReprC => ReprFlags::IS_C,
2054 attr::ReprPacked(pack) => {
2055 let pack = Align::from_bytes(pack as u64).unwrap();
2056 min_pack = Some(if let Some(min_pack) = min_pack {
2063 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2064 attr::ReprSimd => ReprFlags::IS_SIMD,
2065 attr::ReprInt(i) => {
2069 attr::ReprAlign(align) => {
2070 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2077 // If `-Z randomize-layout` was enabled for the type definition then we can
2078 // consider performing layout randomization
2079 if tcx.sess.opts.unstable_opts.randomize_layout {
2080 flags.insert(ReprFlags::RANDOMIZE_LAYOUT);
2083 // This is here instead of layout because the choice must make it into metadata.
2084 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2085 flags.insert(ReprFlags::IS_LINEAR);
2088 Self { int: size, align: max_align, pack: min_pack, flags, field_shuffle_seed }
2092 pub fn simd(&self) -> bool {
2093 self.flags.contains(ReprFlags::IS_SIMD)
2097 pub fn c(&self) -> bool {
2098 self.flags.contains(ReprFlags::IS_C)
2102 pub fn packed(&self) -> bool {
2107 pub fn transparent(&self) -> bool {
2108 self.flags.contains(ReprFlags::IS_TRANSPARENT)
2112 pub fn linear(&self) -> bool {
2113 self.flags.contains(ReprFlags::IS_LINEAR)
2116 /// Returns the discriminant type, given these `repr` options.
2117 /// This must only be called on enums!
2118 pub fn discr_type(&self) -> attr::IntType {
2119 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2122 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2123 /// layout" optimizations, such as representing `Foo<&T>` as a
2125 pub fn inhibit_enum_layout_opt(&self) -> bool {
2126 self.c() || self.int.is_some()
2129 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2130 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2131 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2132 if let Some(pack) = self.pack {
2133 if pack.bytes() == 1 {
2138 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2141 /// Returns `true` if this type is valid for reordering and `-Z randomize-layout`
2142 /// was enabled for its declaration crate
2143 pub fn can_randomize_type_layout(&self) -> bool {
2144 !self.inhibit_struct_field_reordering_opt()
2145 && self.flags.contains(ReprFlags::RANDOMIZE_LAYOUT)
2148 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2149 pub fn inhibit_union_abi_opt(&self) -> bool {
2154 impl<'tcx> FieldDef {
2155 /// Returns the type of this field. The resulting type is not normalized. The `subst` is
2156 /// typically obtained via the second field of [`TyKind::Adt`].
2157 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2158 tcx.bound_type_of(self.did).subst(tcx, subst)
2161 /// Computes the `Ident` of this variant by looking up the `Span`
2162 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
2163 Ident::new(self.name, tcx.def_ident_span(self.did).unwrap())
2167 pub type Attributes<'tcx> = impl Iterator<Item = &'tcx ast::Attribute>;
2168 #[derive(Debug, PartialEq, Eq)]
2169 pub enum ImplOverlapKind {
2170 /// These impls are always allowed to overlap.
2172 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
2175 /// These impls are allowed to overlap, but that raises
2176 /// an issue #33140 future-compatibility warning.
2178 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2179 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2181 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2182 /// that difference, making what reduces to the following set of impls:
2184 /// ```compile_fail,(E0119)
2186 /// impl Trait for dyn Send + Sync {}
2187 /// impl Trait for dyn Sync + Send {}
2190 /// Obviously, once we made these types be identical, that code causes a coherence
2191 /// error and a fairly big headache for us. However, luckily for us, the trait
2192 /// `Trait` used in this case is basically a marker trait, and therefore having
2193 /// overlapping impls for it is sound.
2195 /// To handle this, we basically regard the trait as a marker trait, with an additional
2196 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2197 /// it has the following restrictions:
2199 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2201 /// 2. The trait-ref of both impls must be equal.
2202 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2204 /// 4. Neither of the impls can have any where-clauses.
2206 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2210 impl<'tcx> TyCtxt<'tcx> {
2211 pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> {
2212 self.typeck(self.hir().body_owner_def_id(body))
2215 pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
2216 self.associated_items(id)
2217 .in_definition_order()
2218 .filter(move |item| item.kind == AssocKind::Fn && item.defaultness(self).has_value())
2221 /// Look up the name of a definition across crates. This does not look at HIR.
2222 pub fn opt_item_name(self, def_id: DefId) -> Option<Symbol> {
2223 if let Some(cnum) = def_id.as_crate_root() {
2224 Some(self.crate_name(cnum))
2226 let def_key = self.def_key(def_id);
2227 match def_key.disambiguated_data.data {
2228 // The name of a constructor is that of its parent.
2229 rustc_hir::definitions::DefPathData::Ctor => self
2230 .opt_item_name(DefId { krate: def_id.krate, index: def_key.parent.unwrap() }),
2231 // The name of opaque types only exists in HIR.
2232 rustc_hir::definitions::DefPathData::ImplTrait
2233 if let Some(def_id) = def_id.as_local() =>
2234 self.hir().opt_name(self.hir().local_def_id_to_hir_id(def_id)),
2235 _ => def_key.get_opt_name(),
2240 /// Look up the name of a definition across crates. This does not look at HIR.
2242 /// This method will ICE if the corresponding item does not have a name. In these cases, use
2243 /// [`opt_item_name`] instead.
2245 /// [`opt_item_name`]: Self::opt_item_name
2246 pub fn item_name(self, id: DefId) -> Symbol {
2247 self.opt_item_name(id).unwrap_or_else(|| {
2248 bug!("item_name: no name for {:?}", self.def_path(id));
2252 /// Look up the name and span of a definition.
2254 /// See [`item_name`][Self::item_name] for more information.
2255 pub fn opt_item_ident(self, def_id: DefId) -> Option<Ident> {
2256 let def = self.opt_item_name(def_id)?;
2259 .and_then(|id| self.def_ident_span(id))
2260 .unwrap_or(rustc_span::DUMMY_SP);
2261 Some(Ident::new(def, span))
2264 pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> {
2265 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2266 Some(self.associated_item(def_id))
2272 pub fn field_index(self, hir_id: hir::HirId, typeck_results: &TypeckResults<'_>) -> usize {
2273 typeck_results.field_indices().get(hir_id).cloned().expect("no index for a field")
2276 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2280 .position(|field| self.hygienic_eq(ident, field.ident(self), variant.def_id))
2283 /// Returns `true` if the impls are the same polarity and the trait either
2284 /// has no items or is annotated `#[marker]` and prevents item overrides.
2285 pub fn impls_are_allowed_to_overlap(
2289 ) -> Option<ImplOverlapKind> {
2290 // If either trait impl references an error, they're allowed to overlap,
2291 // as one of them essentially doesn't exist.
2292 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
2293 || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
2295 return Some(ImplOverlapKind::Permitted { marker: false });
2298 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2299 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
2300 // `#[rustc_reservation_impl]` impls don't overlap with anything
2302 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2305 return Some(ImplOverlapKind::Permitted { marker: false });
2307 (ImplPolarity::Positive, ImplPolarity::Negative)
2308 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
2309 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2311 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2316 (ImplPolarity::Positive, ImplPolarity::Positive)
2317 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2320 let is_marker_overlap = {
2321 let is_marker_impl = |def_id: DefId| -> bool {
2322 let trait_ref = self.impl_trait_ref(def_id);
2323 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2325 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2328 if is_marker_overlap {
2330 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2333 Some(ImplOverlapKind::Permitted { marker: true })
2335 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2336 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2337 if self_ty1 == self_ty2 {
2339 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2342 return Some(ImplOverlapKind::Issue33140);
2345 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2346 def_id1, def_id2, self_ty1, self_ty2
2352 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
2357 /// Returns `ty::VariantDef` if `res` refers to a struct,
2358 /// or variant or their constructors, panics otherwise.
2359 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2361 Res::Def(DefKind::Variant, did) => {
2362 let enum_did = self.parent(did);
2363 self.adt_def(enum_did).variant_with_id(did)
2365 Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(),
2366 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2367 let variant_did = self.parent(variant_ctor_did);
2368 let enum_did = self.parent(variant_did);
2369 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2371 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2372 let struct_did = self.parent(ctor_did);
2373 self.adt_def(struct_did).non_enum_variant()
2375 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
2379 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2380 #[instrument(skip(self), level = "debug")]
2381 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
2383 ty::InstanceDef::Item(def) => {
2384 debug!("calling def_kind on def: {:?}", def);
2385 let def_kind = self.def_kind(def.did);
2386 debug!("returned from def_kind: {:?}", def_kind);
2389 | DefKind::Static(..)
2390 | DefKind::AssocConst
2392 | DefKind::AnonConst
2393 | DefKind::InlineConst => self.mir_for_ctfe_opt_const_arg(def),
2394 // If the caller wants `mir_for_ctfe` of a function they should not be using
2395 // `instance_mir`, so we'll assume const fn also wants the optimized version.
2397 assert_eq!(def.const_param_did, None);
2398 self.optimized_mir(def.did)
2402 ty::InstanceDef::VTableShim(..)
2403 | ty::InstanceDef::ReifyShim(..)
2404 | ty::InstanceDef::Intrinsic(..)
2405 | ty::InstanceDef::FnPtrShim(..)
2406 | ty::InstanceDef::Virtual(..)
2407 | ty::InstanceDef::ClosureOnceShim { .. }
2408 | ty::InstanceDef::DropGlue(..)
2409 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance),
2413 // FIXME(@lcnr): Remove this function.
2414 pub fn get_attrs_unchecked(self, did: DefId) -> &'tcx [ast::Attribute] {
2415 if let Some(did) = did.as_local() {
2416 self.hir().attrs(self.hir().local_def_id_to_hir_id(did))
2418 self.item_attrs(did)
2422 /// Gets all attributes with the given name.
2423 pub fn get_attrs(self, did: DefId, attr: Symbol) -> ty::Attributes<'tcx> {
2424 let filter_fn = move |a: &&ast::Attribute| a.has_name(attr);
2425 if let Some(did) = did.as_local() {
2426 self.hir().attrs(self.hir().local_def_id_to_hir_id(did)).iter().filter(filter_fn)
2427 } else if cfg!(debug_assertions) && rustc_feature::is_builtin_only_local(attr) {
2428 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2430 self.item_attrs(did).iter().filter(filter_fn)
2434 pub fn get_attr(self, did: DefId, attr: Symbol) -> Option<&'tcx ast::Attribute> {
2435 if cfg!(debug_assertions) && !rustc_feature::is_valid_for_get_attr(attr) {
2436 bug!("get_attr: unexpected called with DefId `{:?}`, attr `{:?}`", did, attr);
2438 self.get_attrs(did, attr).next()
2442 /// Determines whether an item is annotated with an attribute.
2443 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
2444 if cfg!(debug_assertions) && !did.is_local() && rustc_feature::is_builtin_only_local(attr) {
2445 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2447 self.get_attrs(did, attr).next().is_some()
2451 /// Returns `true` if this is an `auto trait`.
2452 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2453 self.trait_def(trait_def_id).has_auto_impl
2456 pub fn trait_is_coinductive(self, trait_def_id: DefId) -> bool {
2457 self.trait_is_auto(trait_def_id) || self.lang_items().sized_trait() == Some(trait_def_id)
2460 /// Returns layout of a generator. Layout might be unavailable if the
2461 /// generator is tainted by errors.
2462 pub fn generator_layout(self, def_id: DefId) -> Option<&'tcx GeneratorLayout<'tcx>> {
2463 self.optimized_mir(def_id).generator_layout()
2466 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
2467 /// If it implements no trait, returns `None`.
2468 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2469 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2472 /// If the given `DefId` describes an item belonging to a trait,
2473 /// returns the `DefId` of the trait that the trait item belongs to;
2474 /// otherwise, returns `None`.
2475 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2476 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2477 let parent = self.parent(def_id);
2478 if let DefKind::Trait | DefKind::TraitAlias = self.def_kind(parent) {
2479 return Some(parent);
2485 /// If the given `DefId` describes a method belonging to an impl, returns the
2486 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
2487 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2488 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2489 let parent = self.parent(def_id);
2490 if let DefKind::Impl = self.def_kind(parent) {
2491 return Some(parent);
2497 /// If the given `DefId` belongs to a trait that was automatically derived, returns `true`.
2498 pub fn is_builtin_derive(self, def_id: DefId) -> bool {
2499 self.has_attr(def_id, sym::automatically_derived)
2502 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2503 /// with the name of the crate containing the impl.
2504 pub fn span_of_impl(self, impl_def_id: DefId) -> Result<Span, Symbol> {
2505 if let Some(impl_def_id) = impl_def_id.as_local() {
2506 Ok(self.def_span(impl_def_id))
2508 Err(self.crate_name(impl_def_id.krate))
2512 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
2513 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2514 /// definition's parent/scope to perform comparison.
2515 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2516 // We could use `Ident::eq` here, but we deliberately don't. The name
2517 // comparison fails frequently, and we want to avoid the expensive
2518 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
2519 use_name.name == def_name.name
2523 .hygienic_eq(def_name.span.ctxt(), self.expn_that_defined(def_parent_def_id))
2526 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
2527 ident.span.normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope));
2531 pub fn adjust_ident_and_get_scope(
2536 ) -> (Ident, DefId) {
2539 .normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope))
2540 .and_then(|actual_expansion| actual_expansion.expn_data().parent_module)
2541 .unwrap_or_else(|| self.parent_module(block).to_def_id());
2545 /// Returns `true` if the debuginfo for `span` should be collapsed to the outermost expansion
2546 /// site. Only applies when `Span` is the result of macro expansion.
2548 /// - If the `collapse_debuginfo` feature is enabled then debuginfo is not collapsed by default
2549 /// and only when a macro definition is annotated with `#[collapse_debuginfo]`.
2550 /// - If `collapse_debuginfo` is not enabled, then debuginfo is collapsed by default.
2552 /// When `-Zdebug-macros` is provided then debuginfo will never be collapsed.
2553 pub fn should_collapse_debuginfo(self, span: Span) -> bool {
2554 !self.sess.opts.unstable_opts.debug_macros
2555 && if self.features().collapse_debuginfo {
2556 span.in_macro_expansion_with_collapse_debuginfo()
2558 // Inlined spans should not be collapsed as that leads to all of the
2559 // inlined code being attributed to the inline callsite.
2560 span.from_expansion() && !span.is_inlined()
2564 pub fn is_object_safe(self, key: DefId) -> bool {
2565 self.object_safety_violations(key).is_empty()
2569 pub fn is_const_fn_raw(self, def_id: DefId) -> bool {
2570 matches!(self.def_kind(def_id), DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(..))
2571 && self.constness(def_id) == hir::Constness::Const
2575 pub fn is_const_default_method(self, def_id: DefId) -> bool {
2576 matches!(self.trait_of_item(def_id), Some(trait_id) if self.has_attr(trait_id, sym::const_trait))
2579 pub fn impl_trait_in_trait_parent(self, mut def_id: DefId) -> DefId {
2580 while let def_kind = self.def_kind(def_id) && def_kind != DefKind::AssocFn {
2581 debug_assert_eq!(def_kind, DefKind::ImplTraitPlaceholder);
2582 def_id = self.parent(def_id);
2588 /// Yields the parent function's `LocalDefId` if `def_id` is an `impl Trait` definition.
2589 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<LocalDefId> {
2590 let def_id = def_id.as_local()?;
2591 if let Node::Item(item) = tcx.hir().get_by_def_id(def_id) {
2592 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
2593 return match opaque_ty.origin {
2594 hir::OpaqueTyOrigin::FnReturn(parent) | hir::OpaqueTyOrigin::AsyncFn(parent) => {
2597 hir::OpaqueTyOrigin::TyAlias => None,
2604 pub fn int_ty(ity: ast::IntTy) -> IntTy {
2606 ast::IntTy::Isize => IntTy::Isize,
2607 ast::IntTy::I8 => IntTy::I8,
2608 ast::IntTy::I16 => IntTy::I16,
2609 ast::IntTy::I32 => IntTy::I32,
2610 ast::IntTy::I64 => IntTy::I64,
2611 ast::IntTy::I128 => IntTy::I128,
2615 pub fn uint_ty(uty: ast::UintTy) -> UintTy {
2617 ast::UintTy::Usize => UintTy::Usize,
2618 ast::UintTy::U8 => UintTy::U8,
2619 ast::UintTy::U16 => UintTy::U16,
2620 ast::UintTy::U32 => UintTy::U32,
2621 ast::UintTy::U64 => UintTy::U64,
2622 ast::UintTy::U128 => UintTy::U128,
2626 pub fn float_ty(fty: ast::FloatTy) -> FloatTy {
2628 ast::FloatTy::F32 => FloatTy::F32,
2629 ast::FloatTy::F64 => FloatTy::F64,
2633 pub fn ast_int_ty(ity: IntTy) -> ast::IntTy {
2635 IntTy::Isize => ast::IntTy::Isize,
2636 IntTy::I8 => ast::IntTy::I8,
2637 IntTy::I16 => ast::IntTy::I16,
2638 IntTy::I32 => ast::IntTy::I32,
2639 IntTy::I64 => ast::IntTy::I64,
2640 IntTy::I128 => ast::IntTy::I128,
2644 pub fn ast_uint_ty(uty: UintTy) -> ast::UintTy {
2646 UintTy::Usize => ast::UintTy::Usize,
2647 UintTy::U8 => ast::UintTy::U8,
2648 UintTy::U16 => ast::UintTy::U16,
2649 UintTy::U32 => ast::UintTy::U32,
2650 UintTy::U64 => ast::UintTy::U64,
2651 UintTy::U128 => ast::UintTy::U128,
2655 pub fn provide(providers: &mut ty::query::Providers) {
2656 closure::provide(providers);
2657 context::provide(providers);
2658 erase_regions::provide(providers);
2659 inhabitedness::provide(providers);
2660 util::provide(providers);
2661 print::provide(providers);
2662 super::util::bug::provide(providers);
2663 super::middle::provide(providers);
2664 *providers = ty::query::Providers {
2665 trait_impls_of: trait_def::trait_impls_of_provider,
2666 incoherent_impls: trait_def::incoherent_impls_provider,
2667 const_param_default: consts::const_param_default,
2668 vtable_allocation: vtable::vtable_allocation_provider,
2673 /// A map for the local crate mapping each type to a vector of its
2674 /// inherent impls. This is not meant to be used outside of coherence;
2675 /// rather, you should request the vector for a specific type via
2676 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2677 /// (constructing this map requires touching the entire crate).
2678 #[derive(Clone, Debug, Default, HashStable)]
2679 pub struct CrateInherentImpls {
2680 pub inherent_impls: LocalDefIdMap<Vec<DefId>>,
2681 pub incoherent_impls: FxHashMap<SimplifiedType, Vec<LocalDefId>>,
2684 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]
2685 pub struct SymbolName<'tcx> {
2686 /// `&str` gives a consistent ordering, which ensures reproducible builds.
2687 pub name: &'tcx str,
2690 impl<'tcx> SymbolName<'tcx> {
2691 pub fn new(tcx: TyCtxt<'tcx>, name: &str) -> SymbolName<'tcx> {
2693 name: unsafe { str::from_utf8_unchecked(tcx.arena.alloc_slice(name.as_bytes())) },
2698 impl<'tcx> fmt::Display for SymbolName<'tcx> {
2699 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2700 fmt::Display::fmt(&self.name, fmt)
2704 impl<'tcx> fmt::Debug for SymbolName<'tcx> {
2705 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2706 fmt::Display::fmt(&self.name, fmt)
2710 #[derive(Debug, Default, Copy, Clone)]
2711 pub struct FoundRelationships {
2712 /// This is true if we identified that this Ty (`?T`) is found in a `?T: Foo`
2713 /// obligation, where:
2715 /// * `Foo` is not `Sized`
2716 /// * `(): Foo` may be satisfied
2717 pub self_in_trait: bool,
2718 /// This is true if we identified that this Ty (`?T`) is found in a `<_ as
2719 /// _>::AssocType = ?T`
2723 /// The constituent parts of a type level constant of kind ADT or array.
2724 #[derive(Copy, Clone, Debug, HashStable)]
2725 pub struct DestructuredConst<'tcx> {
2726 pub variant: Option<VariantIdx>,
2727 pub fields: &'tcx [ty::Const<'tcx>],
2730 // Some types are used a lot. Make sure they don't unintentionally get bigger.
2731 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2734 use rustc_data_structures::static_assert_size;
2735 // tidy-alphabetical-start
2736 static_assert_size!(PredicateS<'_>, 48);
2737 static_assert_size!(TyS<'_>, 40);
2738 static_assert_size!(WithStableHash<TyS<'_>>, 56);
2739 // tidy-alphabetical-end