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, PolyExistentialProjection,
98 PolyExistentialTraitRef, PolyFnSig, PolyGenSig, PolyTraitRef, ProjectionTy, Region, RegionKind,
99 RegionVid, TraitRef, TyKind, TypeAndMut, UpvarSubsts, VarianceDiagInfo,
101 pub use self::trait_def::TraitDef;
104 pub mod abstract_const;
113 pub mod inhabitedness;
115 pub mod normalize_erasing_regions;
140 mod structural_impls;
145 pub type RegisteredTools = FxHashSet<Ident>;
147 pub struct ResolverOutputs {
148 pub definitions: Definitions,
149 pub global_ctxt: ResolverGlobalCtxt,
150 pub ast_lowering: ResolverAstLowering,
154 pub struct ResolverGlobalCtxt {
155 pub cstore: Box<CrateStoreDyn>,
156 pub visibilities: FxHashMap<LocalDefId, Visibility>,
157 /// This field is used to decide whether we should make `PRIVATE_IN_PUBLIC` a hard error.
158 pub has_pub_restricted: bool,
159 /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
160 pub expn_that_defined: FxHashMap<LocalDefId, ExpnId>,
161 /// Reference span for definitions.
162 pub source_span: IndexVec<LocalDefId, Span>,
163 pub effective_visibilities: EffectiveVisibilities,
164 pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
165 pub maybe_unused_trait_imports: FxIndexSet<LocalDefId>,
166 pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
167 pub reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
168 pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
169 /// Extern prelude entries. The value is `true` if the entry was introduced
170 /// via `extern crate` item and not `--extern` option or compiler built-in.
171 pub extern_prelude: FxHashMap<Symbol, bool>,
172 pub main_def: Option<MainDefinition>,
173 pub trait_impls: FxIndexMap<DefId, Vec<LocalDefId>>,
174 /// A list of proc macro LocalDefIds, written out in the order in which
175 /// they are declared in the static array generated by proc_macro_harness.
176 pub proc_macros: Vec<LocalDefId>,
177 /// Mapping from ident span to path span for paths that don't exist as written, but that
178 /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
179 pub confused_type_with_std_module: FxHashMap<Span, Span>,
180 pub registered_tools: RegisteredTools,
183 /// Resolutions that should only be used for lowering.
184 /// This struct is meant to be consumed by lowering.
186 pub struct ResolverAstLowering {
187 pub legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
189 /// Resolutions for nodes that have a single resolution.
190 pub partial_res_map: NodeMap<hir::def::PartialRes>,
191 /// Resolutions for import nodes, which have multiple resolutions in different namespaces.
192 pub import_res_map: NodeMap<hir::def::PerNS<Option<Res<ast::NodeId>>>>,
193 /// Resolutions for labels (node IDs of their corresponding blocks or loops).
194 pub label_res_map: NodeMap<ast::NodeId>,
195 /// Resolutions for lifetimes.
196 pub lifetimes_res_map: NodeMap<LifetimeRes>,
197 /// Lifetime parameters that lowering will have to introduce.
198 pub extra_lifetime_params_map: NodeMap<Vec<(Ident, ast::NodeId, LifetimeRes)>>,
200 pub next_node_id: ast::NodeId,
202 pub node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
203 pub def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
205 pub trait_map: NodeMap<Vec<hir::TraitCandidate>>,
206 /// A small map keeping true kinds of built-in macros that appear to be fn-like on
207 /// the surface (`macro` items in libcore), but are actually attributes or derives.
208 pub builtin_macro_kinds: FxHashMap<LocalDefId, MacroKind>,
211 #[derive(Clone, Copy, Debug)]
212 pub struct MainDefinition {
213 pub res: Res<ast::NodeId>,
218 impl MainDefinition {
219 pub fn opt_fn_def_id(self) -> Option<DefId> {
220 if let Res::Def(DefKind::Fn, def_id) = self.res { Some(def_id) } else { None }
224 /// The "header" of an impl is everything outside the body: a Self type, a trait
225 /// ref (in the case of a trait impl), and a set of predicates (from the
226 /// bounds / where-clauses).
227 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
228 pub struct ImplHeader<'tcx> {
229 pub impl_def_id: DefId,
230 pub self_ty: Ty<'tcx>,
231 pub trait_ref: Option<TraitRef<'tcx>>,
232 pub predicates: Vec<Predicate<'tcx>>,
235 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
236 pub enum ImplSubject<'tcx> {
237 Trait(TraitRef<'tcx>),
241 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable, Debug)]
242 #[derive(TypeFoldable, TypeVisitable)]
243 pub enum ImplPolarity {
244 /// `impl Trait for Type`
246 /// `impl !Trait for Type`
248 /// `#[rustc_reservation_impl] impl Trait for Type`
250 /// This is a "stability hack", not a real Rust feature.
251 /// See #64631 for details.
256 /// Flips polarity by turning `Positive` into `Negative` and `Negative` into `Positive`.
257 pub fn flip(&self) -> Option<ImplPolarity> {
259 ImplPolarity::Positive => Some(ImplPolarity::Negative),
260 ImplPolarity::Negative => Some(ImplPolarity::Positive),
261 ImplPolarity::Reservation => None,
266 impl fmt::Display for ImplPolarity {
267 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
269 Self::Positive => f.write_str("positive"),
270 Self::Negative => f.write_str("negative"),
271 Self::Reservation => f.write_str("reservation"),
276 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, Encodable, Decodable, HashStable)]
277 pub enum Visibility<Id = LocalDefId> {
278 /// Visible everywhere (including in other crates).
280 /// Visible only in the given crate-local module.
284 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
285 pub enum BoundConstness {
288 /// `T: ~const Trait`
290 /// Requires resolving to const only when we are in a const context.
294 impl BoundConstness {
295 /// Reduce `self` and `constness` to two possible combined states instead of four.
296 pub fn and(&mut self, constness: hir::Constness) -> hir::Constness {
297 match (constness, self) {
298 (hir::Constness::Const, BoundConstness::ConstIfConst) => hir::Constness::Const,
300 *this = BoundConstness::NotConst;
301 hir::Constness::NotConst
307 impl fmt::Display for BoundConstness {
308 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
310 Self::NotConst => f.write_str("normal"),
311 Self::ConstIfConst => f.write_str("`~const`"),
316 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, TyEncodable, TyDecodable, HashStable)]
317 #[derive(TypeFoldable, TypeVisitable)]
318 pub struct ClosureSizeProfileData<'tcx> {
319 /// Tuple containing the types of closure captures before the feature `capture_disjoint_fields`
320 pub before_feature_tys: Ty<'tcx>,
321 /// Tuple containing the types of closure captures after the feature `capture_disjoint_fields`
322 pub after_feature_tys: Ty<'tcx>,
325 pub trait DefIdTree: Copy {
326 fn opt_parent(self, id: DefId) -> Option<DefId>;
330 fn parent(self, id: DefId) -> DefId {
331 match self.opt_parent(id) {
333 // not `unwrap_or_else` to avoid breaking caller tracking
334 None => bug!("{id:?} doesn't have a parent"),
340 fn opt_local_parent(self, id: LocalDefId) -> Option<LocalDefId> {
341 self.opt_parent(id.to_def_id()).map(DefId::expect_local)
346 fn local_parent(self, id: LocalDefId) -> LocalDefId {
347 self.parent(id.to_def_id()).expect_local()
350 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
351 if descendant.krate != ancestor.krate {
355 while descendant != ancestor {
356 match self.opt_parent(descendant) {
357 Some(parent) => descendant = parent,
358 None => return false,
365 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
367 fn opt_parent(self, id: DefId) -> Option<DefId> {
368 self.def_key(id).parent.map(|index| DefId { index, ..id })
372 impl<Id> Visibility<Id> {
373 pub fn is_public(self) -> bool {
374 matches!(self, Visibility::Public)
377 pub fn map_id<OutId>(self, f: impl FnOnce(Id) -> OutId) -> Visibility<OutId> {
379 Visibility::Public => Visibility::Public,
380 Visibility::Restricted(id) => Visibility::Restricted(f(id)),
385 impl<Id: Into<DefId>> Visibility<Id> {
386 pub fn to_def_id(self) -> Visibility<DefId> {
387 self.map_id(Into::into)
390 /// Returns `true` if an item with this visibility is accessible from the given module.
391 pub fn is_accessible_from(self, module: impl Into<DefId>, tree: impl DefIdTree) -> bool {
393 // Public items are visible everywhere.
394 Visibility::Public => true,
395 Visibility::Restricted(id) => tree.is_descendant_of(module.into(), id.into()),
399 /// Returns `true` if this visibility is at least as accessible as the given visibility
400 pub fn is_at_least(self, vis: Visibility<impl Into<DefId>>, tree: impl DefIdTree) -> bool {
402 Visibility::Public => self.is_public(),
403 Visibility::Restricted(id) => self.is_accessible_from(id, tree),
408 impl Visibility<DefId> {
409 pub fn expect_local(self) -> Visibility {
410 self.map_id(|id| id.expect_local())
413 // Returns `true` if this item is visible anywhere in the local crate.
414 pub fn is_visible_locally(self) -> bool {
416 Visibility::Public => true,
417 Visibility::Restricted(def_id) => def_id.is_local(),
422 /// The crate variances map is computed during typeck and contains the
423 /// variance of every item in the local crate. You should not use it
424 /// directly, because to do so will make your pass dependent on the
425 /// HIR of every item in the local crate. Instead, use
426 /// `tcx.variances_of()` to get the variance for a *particular*
428 #[derive(HashStable, Debug)]
429 pub struct CrateVariancesMap<'tcx> {
430 /// For each item with generics, maps to a vector of the variance
431 /// of its generics. If an item has no generics, it will have no
433 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
436 // Contains information needed to resolve types and (in the future) look up
437 // the types of AST nodes.
438 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
439 pub struct CReaderCacheKey {
440 pub cnum: Option<CrateNum>,
444 /// Represents a type.
447 /// - This is a very "dumb" struct (with no derives and no `impls`).
448 /// - Values of this type are always interned and thus unique, and are stored
449 /// as an `Interned<TyS>`.
450 /// - `Ty` (which contains a reference to a `Interned<TyS>`) or `Interned<TyS>`
451 /// should be used everywhere instead of `TyS`. In particular, `Ty` has most
452 /// of the relevant methods.
453 #[derive(PartialEq, Eq, PartialOrd, Ord)]
454 #[allow(rustc::usage_of_ty_tykind)]
455 pub(crate) struct TyS<'tcx> {
456 /// This field shouldn't be used directly and may be removed in the future.
457 /// Use `Ty::kind()` instead.
460 /// This field provides fast access to information that is also contained
463 /// This field shouldn't be used directly and may be removed in the future.
464 /// Use `Ty::flags()` instead.
467 /// This field provides fast access to information that is also contained
470 /// This is a kind of confusing thing: it stores the smallest
473 /// (a) the binder itself captures nothing but
474 /// (b) all the late-bound things within the type are captured
475 /// by some sub-binder.
477 /// So, for a type without any late-bound things, like `u32`, this
478 /// will be *innermost*, because that is the innermost binder that
479 /// captures nothing. But for a type `&'D u32`, where `'D` is a
480 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
481 /// -- the binder itself does not capture `D`, but `D` is captured
482 /// by an inner binder.
484 /// We call this concept an "exclusive" binder `D` because all
485 /// De Bruijn indices within the type are contained within `0..D`
487 outer_exclusive_binder: ty::DebruijnIndex,
490 /// Use this rather than `TyS`, whenever possible.
491 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)]
492 #[rustc_diagnostic_item = "Ty"]
493 #[rustc_pass_by_value]
494 pub struct Ty<'tcx>(Interned<'tcx, WithStableHash<TyS<'tcx>>>);
496 impl<'tcx> TyCtxt<'tcx> {
497 /// A "bool" type used in rustc_mir_transform unit tests when we
498 /// have not spun up a TyCtxt.
499 pub const BOOL_TY_FOR_UNIT_TESTING: Ty<'tcx> = Ty(Interned::new_unchecked(&WithStableHash {
502 flags: TypeFlags::empty(),
503 outer_exclusive_binder: DebruijnIndex::from_usize(0),
505 stable_hash: Fingerprint::ZERO,
509 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
511 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
515 // The other fields just provide fast access to information that is
516 // also contained in `kind`, so no need to hash them.
519 outer_exclusive_binder: _,
522 kind.hash_stable(hcx, hasher)
526 impl ty::EarlyBoundRegion {
527 /// Does this early bound region have a name? Early bound regions normally
528 /// always have names except when using anonymous lifetimes (`'_`).
529 pub fn has_name(&self) -> bool {
530 self.name != kw::UnderscoreLifetime
534 /// Represents a predicate.
536 /// See comments on `TyS`, which apply here too (albeit for
537 /// `PredicateS`/`Predicate` rather than `TyS`/`Ty`).
539 pub(crate) struct PredicateS<'tcx> {
540 kind: Binder<'tcx, PredicateKind<'tcx>>,
542 /// See the comment for the corresponding field of [TyS].
543 outer_exclusive_binder: ty::DebruijnIndex,
546 /// Use this rather than `PredicateS`, whenever possible.
547 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
548 #[rustc_pass_by_value]
549 pub struct Predicate<'tcx>(Interned<'tcx, PredicateS<'tcx>>);
551 impl<'tcx> Predicate<'tcx> {
552 /// Gets the inner `Binder<'tcx, PredicateKind<'tcx>>`.
554 pub fn kind(self) -> Binder<'tcx, PredicateKind<'tcx>> {
559 pub fn flags(self) -> TypeFlags {
564 pub fn outer_exclusive_binder(self) -> DebruijnIndex {
565 self.0.outer_exclusive_binder
568 /// Flips the polarity of a Predicate.
570 /// Given `T: Trait` predicate it returns `T: !Trait` and given `T: !Trait` returns `T: Trait`.
571 pub fn flip_polarity(self, tcx: TyCtxt<'tcx>) -> Option<Predicate<'tcx>> {
574 .map_bound(|kind| match kind {
575 PredicateKind::Trait(TraitPredicate { trait_ref, constness, polarity }) => {
576 Some(PredicateKind::Trait(TraitPredicate {
579 polarity: polarity.flip()?,
587 Some(tcx.mk_predicate(kind))
590 pub fn without_const(mut self, tcx: TyCtxt<'tcx>) -> Self {
591 if let PredicateKind::Trait(TraitPredicate { trait_ref, constness, polarity }) = self.kind().skip_binder()
592 && constness != BoundConstness::NotConst
594 self = tcx.mk_predicate(self.kind().rebind(PredicateKind::Trait(TraitPredicate {
596 constness: BoundConstness::NotConst,
603 /// Whether this projection can be soundly normalized.
605 /// Wf predicates must not be normalized, as normalization
606 /// can remove required bounds which would cause us to
607 /// unsoundly accept some programs. See #91068.
609 pub fn allow_normalization(self) -> bool {
610 match self.kind().skip_binder() {
611 PredicateKind::WellFormed(_) => false,
612 PredicateKind::Trait(_)
613 | PredicateKind::RegionOutlives(_)
614 | PredicateKind::TypeOutlives(_)
615 | PredicateKind::Projection(_)
616 | PredicateKind::ObjectSafe(_)
617 | PredicateKind::ClosureKind(_, _, _)
618 | PredicateKind::Subtype(_)
619 | PredicateKind::Coerce(_)
620 | PredicateKind::ConstEvaluatable(_)
621 | PredicateKind::ConstEquate(_, _)
622 | PredicateKind::TypeWellFormedFromEnv(_) => true,
627 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {
628 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
632 // The other fields just provide fast access to information that is
633 // also contained in `kind`, so no need to hash them.
635 outer_exclusive_binder: _,
638 kind.hash_stable(hcx, hasher);
642 impl rustc_errors::IntoDiagnosticArg for Predicate<'_> {
643 fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
644 rustc_errors::DiagnosticArgValue::Str(std::borrow::Cow::Owned(self.to_string()))
648 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
649 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
650 pub enum PredicateKind<'tcx> {
651 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
652 /// the `Self` type of the trait reference and `A`, `B`, and `C`
653 /// would be the type parameters.
654 Trait(TraitPredicate<'tcx>),
657 RegionOutlives(RegionOutlivesPredicate<'tcx>),
660 TypeOutlives(TypeOutlivesPredicate<'tcx>),
662 /// `where <T as TraitRef>::Name == X`, approximately.
663 /// See the `ProjectionPredicate` struct for details.
664 Projection(ProjectionPredicate<'tcx>),
666 /// No syntax: `T` well-formed.
667 WellFormed(GenericArg<'tcx>),
669 /// Trait must be object-safe.
672 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
673 /// for some substitutions `...` and `T` being a closure type.
674 /// Satisfied (or refuted) once we know the closure's kind.
675 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
679 /// This obligation is created most often when we have two
680 /// unresolved type variables and hence don't have enough
681 /// information to process the subtyping obligation yet.
682 Subtype(SubtypePredicate<'tcx>),
684 /// `T1` coerced to `T2`
686 /// Like a subtyping obligation, this is created most often
687 /// when we have two unresolved type variables and hence
688 /// don't have enough information to process the coercion
689 /// obligation yet. At the moment, we actually process coercions
690 /// very much like subtyping and don't handle the full coercion
692 Coerce(CoercePredicate<'tcx>),
694 /// Constant initializer must evaluate successfully.
695 ConstEvaluatable(ty::Const<'tcx>),
697 /// Constants must be equal. The first component is the const that is expected.
698 ConstEquate(Const<'tcx>, Const<'tcx>),
700 /// Represents a type found in the environment that we can use for implied bounds.
702 /// Only used for Chalk.
703 TypeWellFormedFromEnv(Ty<'tcx>),
706 /// The crate outlives map is computed during typeck and contains the
707 /// outlives of every item in the local crate. You should not use it
708 /// directly, because to do so will make your pass dependent on the
709 /// HIR of every item in the local crate. Instead, use
710 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
712 #[derive(HashStable, Debug)]
713 pub struct CratePredicatesMap<'tcx> {
714 /// For each struct with outlive bounds, maps to a vector of the
715 /// predicate of its outlive bounds. If an item has no outlives
716 /// bounds, it will have no entry.
717 pub predicates: FxHashMap<DefId, &'tcx [(Predicate<'tcx>, Span)]>,
720 impl<'tcx> Predicate<'tcx> {
721 /// Performs a substitution suitable for going from a
722 /// poly-trait-ref to supertraits that must hold if that
723 /// poly-trait-ref holds. This is slightly different from a normal
724 /// substitution in terms of what happens with bound regions. See
725 /// lengthy comment below for details.
726 pub fn subst_supertrait(
729 trait_ref: &ty::PolyTraitRef<'tcx>,
730 ) -> Predicate<'tcx> {
731 // The interaction between HRTB and supertraits is not entirely
732 // obvious. Let me walk you (and myself) through an example.
734 // Let's start with an easy case. Consider two traits:
736 // trait Foo<'a>: Bar<'a,'a> { }
737 // trait Bar<'b,'c> { }
739 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
740 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
741 // knew that `Foo<'x>` (for any 'x) then we also know that
742 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
743 // normal substitution.
745 // In terms of why this is sound, the idea is that whenever there
746 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
747 // holds. So if there is an impl of `T:Foo<'a>` that applies to
748 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
751 // Another example to be careful of is this:
753 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
754 // trait Bar1<'b,'c> { }
756 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
757 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
758 // reason is similar to the previous example: any impl of
759 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
760 // basically we would want to collapse the bound lifetimes from
761 // the input (`trait_ref`) and the supertraits.
763 // To achieve this in practice is fairly straightforward. Let's
764 // consider the more complicated scenario:
766 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
767 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
768 // where both `'x` and `'b` would have a DB index of 1.
769 // The substitution from the input trait-ref is therefore going to be
770 // `'a => 'x` (where `'x` has a DB index of 1).
771 // - The supertrait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
772 // early-bound parameter and `'b' is a late-bound parameter with a
774 // - If we replace `'a` with `'x` from the input, it too will have
775 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
776 // just as we wanted.
778 // There is only one catch. If we just apply the substitution `'a
779 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
780 // adjust the DB index because we substituting into a binder (it
781 // tries to be so smart...) resulting in `for<'x> for<'b>
782 // Bar1<'x,'b>` (we have no syntax for this, so use your
783 // imagination). Basically the 'x will have DB index of 2 and 'b
784 // will have DB index of 1. Not quite what we want. So we apply
785 // the substitution to the *contents* of the trait reference,
786 // rather than the trait reference itself (put another way, the
787 // substitution code expects equal binding levels in the values
788 // from the substitution and the value being substituted into, and
789 // this trick achieves that).
791 // Working through the second example:
792 // trait_ref: for<'x> T: Foo1<'^0.0>; substs: [T, '^0.0]
793 // predicate: for<'b> Self: Bar1<'a, '^0.0>; substs: [Self, 'a, '^0.0]
794 // We want to end up with:
795 // for<'x, 'b> T: Bar1<'^0.0, '^0.1>
797 // 1) We must shift all bound vars in predicate by the length
798 // of trait ref's bound vars. So, we would end up with predicate like
799 // Self: Bar1<'a, '^0.1>
800 // 2) We can then apply the trait substs to this, ending up with
801 // T: Bar1<'^0.0, '^0.1>
802 // 3) Finally, to create the final bound vars, we concatenate the bound
803 // vars of the trait ref with those of the predicate:
805 let bound_pred = self.kind();
806 let pred_bound_vars = bound_pred.bound_vars();
807 let trait_bound_vars = trait_ref.bound_vars();
808 // 1) Self: Bar1<'a, '^0.0> -> Self: Bar1<'a, '^0.1>
810 tcx.shift_bound_var_indices(trait_bound_vars.len(), bound_pred.skip_binder());
811 // 2) Self: Bar1<'a, '^0.1> -> T: Bar1<'^0.0, '^0.1>
812 let new = EarlyBinder(shifted_pred).subst(tcx, trait_ref.skip_binder().substs);
813 // 3) ['x] + ['b] -> ['x, 'b]
815 tcx.mk_bound_variable_kinds(trait_bound_vars.iter().chain(pred_bound_vars));
816 tcx.reuse_or_mk_predicate(self, ty::Binder::bind_with_vars(new, bound_vars))
820 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
821 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
822 pub struct TraitPredicate<'tcx> {
823 pub trait_ref: TraitRef<'tcx>,
825 pub constness: BoundConstness,
827 /// If polarity is Positive: we are proving that the trait is implemented.
829 /// If polarity is Negative: we are proving that a negative impl of this trait
830 /// exists. (Note that coherence also checks whether negative impls of supertraits
831 /// exist via a series of predicates.)
833 /// If polarity is Reserved: that's a bug.
834 pub polarity: ImplPolarity,
837 pub type PolyTraitPredicate<'tcx> = ty::Binder<'tcx, TraitPredicate<'tcx>>;
839 impl<'tcx> TraitPredicate<'tcx> {
840 pub fn remap_constness(&mut self, param_env: &mut ParamEnv<'tcx>) {
841 *param_env = param_env.with_constness(self.constness.and(param_env.constness()))
844 /// Remap the constness of this predicate before emitting it for diagnostics.
845 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
846 // this is different to `remap_constness` that callees want to print this predicate
847 // in case of selection errors. `T: ~const Drop` bounds cannot end up here when the
848 // param_env is not const because it is always satisfied in non-const contexts.
849 if let hir::Constness::NotConst = param_env.constness() {
850 self.constness = ty::BoundConstness::NotConst;
854 pub fn def_id(self) -> DefId {
855 self.trait_ref.def_id
858 pub fn self_ty(self) -> Ty<'tcx> {
859 self.trait_ref.self_ty()
863 pub fn is_const_if_const(self) -> bool {
864 self.constness == BoundConstness::ConstIfConst
867 pub fn is_constness_satisfied_by(self, constness: hir::Constness) -> bool {
868 match (self.constness, constness) {
869 (BoundConstness::NotConst, _)
870 | (BoundConstness::ConstIfConst, hir::Constness::Const) => true,
871 (BoundConstness::ConstIfConst, hir::Constness::NotConst) => false,
875 pub fn without_const(mut self) -> Self {
876 self.constness = BoundConstness::NotConst;
881 impl<'tcx> PolyTraitPredicate<'tcx> {
882 pub fn def_id(self) -> DefId {
883 // Ok to skip binder since trait `DefId` does not care about regions.
884 self.skip_binder().def_id()
887 pub fn self_ty(self) -> ty::Binder<'tcx, Ty<'tcx>> {
888 self.map_bound(|trait_ref| trait_ref.self_ty())
891 /// Remap the constness of this predicate before emitting it for diagnostics.
892 pub fn remap_constness_diag(&mut self, param_env: ParamEnv<'tcx>) {
893 *self = self.map_bound(|mut p| {
894 p.remap_constness_diag(param_env);
900 pub fn is_const_if_const(self) -> bool {
901 self.skip_binder().is_const_if_const()
905 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
906 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
907 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
908 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
909 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
910 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<'tcx, RegionOutlivesPredicate<'tcx>>;
911 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<'tcx, TypeOutlivesPredicate<'tcx>>;
913 /// Encodes that `a` must be a subtype of `b`. The `a_is_expected` flag indicates
914 /// whether the `a` type is the type that we should label as "expected" when
915 /// presenting user diagnostics.
916 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
917 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
918 pub struct SubtypePredicate<'tcx> {
919 pub a_is_expected: bool,
923 pub type PolySubtypePredicate<'tcx> = ty::Binder<'tcx, SubtypePredicate<'tcx>>;
925 /// Encodes that we have to coerce *from* the `a` type to the `b` type.
926 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
927 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
928 pub struct CoercePredicate<'tcx> {
932 pub type PolyCoercePredicate<'tcx> = ty::Binder<'tcx, CoercePredicate<'tcx>>;
934 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
935 pub struct Term<'tcx> {
937 marker: PhantomData<(Ty<'tcx>, Const<'tcx>)>,
940 impl Debug for Term<'_> {
941 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
942 let data = if let Some(ty) = self.ty() {
943 format!("Term::Ty({:?})", ty)
944 } else if let Some(ct) = self.ct() {
945 format!("Term::Ct({:?})", ct)
953 impl<'tcx> From<Ty<'tcx>> for Term<'tcx> {
954 fn from(ty: Ty<'tcx>) -> Self {
955 TermKind::Ty(ty).pack()
959 impl<'tcx> From<Const<'tcx>> for Term<'tcx> {
960 fn from(c: Const<'tcx>) -> Self {
961 TermKind::Const(c).pack()
965 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Term<'tcx> {
966 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
967 self.unpack().hash_stable(hcx, hasher);
971 impl<'tcx> TypeFoldable<'tcx> for Term<'tcx> {
972 fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
973 Ok(self.unpack().try_fold_with(folder)?.pack())
977 impl<'tcx> TypeVisitable<'tcx> for Term<'tcx> {
978 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
979 self.unpack().visit_with(visitor)
983 impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for Term<'tcx> {
984 fn encode(&self, e: &mut E) {
985 self.unpack().encode(e)
989 impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for Term<'tcx> {
990 fn decode(d: &mut D) -> Self {
991 let res: TermKind<'tcx> = Decodable::decode(d);
996 impl<'tcx> Term<'tcx> {
998 pub fn unpack(self) -> TermKind<'tcx> {
999 let ptr = self.ptr.get();
1000 // SAFETY: use of `Interned::new_unchecked` here is ok because these
1001 // pointers were originally created from `Interned` types in `pack()`,
1002 // and this is just going in the other direction.
1004 match ptr & TAG_MASK {
1005 TYPE_TAG => TermKind::Ty(Ty(Interned::new_unchecked(
1006 &*((ptr & !TAG_MASK) as *const WithStableHash<ty::TyS<'tcx>>),
1008 CONST_TAG => TermKind::Const(ty::Const(Interned::new_unchecked(
1009 &*((ptr & !TAG_MASK) as *const ty::ConstS<'tcx>),
1011 _ => core::intrinsics::unreachable(),
1016 pub fn ty(&self) -> Option<Ty<'tcx>> {
1017 if let TermKind::Ty(ty) = self.unpack() { Some(ty) } else { None }
1020 pub fn ct(&self) -> Option<Const<'tcx>> {
1021 if let TermKind::Const(c) = self.unpack() { Some(c) } else { None }
1024 pub fn into_arg(self) -> GenericArg<'tcx> {
1025 match self.unpack() {
1026 TermKind::Ty(ty) => ty.into(),
1027 TermKind::Const(c) => c.into(),
1032 const TAG_MASK: usize = 0b11;
1033 const TYPE_TAG: usize = 0b00;
1034 const CONST_TAG: usize = 0b01;
1036 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
1037 #[derive(HashStable, TypeFoldable, TypeVisitable)]
1038 pub enum TermKind<'tcx> {
1043 impl<'tcx> TermKind<'tcx> {
1045 fn pack(self) -> Term<'tcx> {
1046 let (tag, ptr) = match self {
1047 TermKind::Ty(ty) => {
1048 // Ensure we can use the tag bits.
1049 assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
1050 (TYPE_TAG, ty.0.0 as *const WithStableHash<ty::TyS<'tcx>> as usize)
1052 TermKind::Const(ct) => {
1053 // Ensure we can use the tag bits.
1054 assert_eq!(mem::align_of_val(&*ct.0.0) & TAG_MASK, 0);
1055 (CONST_TAG, ct.0.0 as *const ty::ConstS<'tcx> as usize)
1059 Term { ptr: unsafe { NonZeroUsize::new_unchecked(ptr | tag) }, marker: PhantomData }
1063 /// This kind of predicate has no *direct* correspondent in the
1064 /// syntax, but it roughly corresponds to the syntactic forms:
1066 /// 1. `T: TraitRef<..., Item = Type>`
1067 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1069 /// In particular, form #1 is "desugared" to the combination of a
1070 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1071 /// predicates. Form #2 is a broader form in that it also permits
1072 /// equality between arbitrary types. Processing an instance of
1073 /// Form #2 eventually yields one of these `ProjectionPredicate`
1074 /// instances to normalize the LHS.
1075 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
1076 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
1077 pub struct ProjectionPredicate<'tcx> {
1078 pub projection_ty: ProjectionTy<'tcx>,
1079 pub term: Term<'tcx>,
1082 pub type PolyProjectionPredicate<'tcx> = Binder<'tcx, ProjectionPredicate<'tcx>>;
1084 impl<'tcx> PolyProjectionPredicate<'tcx> {
1085 /// Returns the `DefId` of the trait of the associated item being projected.
1087 pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
1088 self.skip_binder().projection_ty.trait_def_id(tcx)
1091 /// Get the [PolyTraitRef] required for this projection to be well formed.
1092 /// Note that for generic associated types the predicates of the associated
1093 /// type also need to be checked.
1095 pub fn required_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
1096 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1097 // `self.0.trait_ref` is permitted to have escaping regions.
1098 // This is because here `self` has a `Binder` and so does our
1099 // return value, so we are preserving the number of binding
1101 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1104 pub fn term(&self) -> Binder<'tcx, Term<'tcx>> {
1105 self.map_bound(|predicate| predicate.term)
1108 /// The `DefId` of the `TraitItem` for the associated type.
1110 /// Note that this is not the `DefId` of the `TraitRef` containing this
1111 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1112 pub fn projection_def_id(&self) -> DefId {
1113 // Ok to skip binder since trait `DefId` does not care about regions.
1114 self.skip_binder().projection_ty.item_def_id
1118 pub trait ToPolyTraitRef<'tcx> {
1119 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1122 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1123 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1124 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1128 pub trait ToPredicate<'tcx, Predicate> {
1129 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate;
1132 impl<'tcx, T> ToPredicate<'tcx, T> for T {
1133 fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T {
1138 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for Binder<'tcx, PredicateKind<'tcx>> {
1140 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1141 tcx.mk_predicate(self)
1145 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyTraitPredicate<'tcx> {
1146 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1147 self.map_bound(PredicateKind::Trait).to_predicate(tcx)
1151 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyRegionOutlivesPredicate<'tcx> {
1152 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1153 self.map_bound(PredicateKind::RegionOutlives).to_predicate(tcx)
1157 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyTypeOutlivesPredicate<'tcx> {
1158 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1159 self.map_bound(PredicateKind::TypeOutlives).to_predicate(tcx)
1163 impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyProjectionPredicate<'tcx> {
1164 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
1165 self.map_bound(PredicateKind::Projection).to_predicate(tcx)
1169 impl<'tcx> Predicate<'tcx> {
1170 pub fn to_opt_poly_trait_pred(self) -> Option<PolyTraitPredicate<'tcx>> {
1171 let predicate = self.kind();
1172 match predicate.skip_binder() {
1173 PredicateKind::Trait(t) => Some(predicate.rebind(t)),
1174 PredicateKind::Projection(..)
1175 | PredicateKind::Subtype(..)
1176 | PredicateKind::Coerce(..)
1177 | PredicateKind::RegionOutlives(..)
1178 | PredicateKind::WellFormed(..)
1179 | PredicateKind::ObjectSafe(..)
1180 | PredicateKind::ClosureKind(..)
1181 | PredicateKind::TypeOutlives(..)
1182 | PredicateKind::ConstEvaluatable(..)
1183 | PredicateKind::ConstEquate(..)
1184 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1188 pub fn to_opt_poly_projection_pred(self) -> Option<PolyProjectionPredicate<'tcx>> {
1189 let predicate = self.kind();
1190 match predicate.skip_binder() {
1191 PredicateKind::Projection(t) => Some(predicate.rebind(t)),
1192 PredicateKind::Trait(..)
1193 | PredicateKind::Subtype(..)
1194 | PredicateKind::Coerce(..)
1195 | PredicateKind::RegionOutlives(..)
1196 | PredicateKind::WellFormed(..)
1197 | PredicateKind::ObjectSafe(..)
1198 | PredicateKind::ClosureKind(..)
1199 | PredicateKind::TypeOutlives(..)
1200 | PredicateKind::ConstEvaluatable(..)
1201 | PredicateKind::ConstEquate(..)
1202 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1206 pub fn to_opt_type_outlives(self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1207 let predicate = self.kind();
1208 match predicate.skip_binder() {
1209 PredicateKind::TypeOutlives(data) => Some(predicate.rebind(data)),
1210 PredicateKind::Trait(..)
1211 | PredicateKind::Projection(..)
1212 | PredicateKind::Subtype(..)
1213 | PredicateKind::Coerce(..)
1214 | PredicateKind::RegionOutlives(..)
1215 | PredicateKind::WellFormed(..)
1216 | PredicateKind::ObjectSafe(..)
1217 | PredicateKind::ClosureKind(..)
1218 | PredicateKind::ConstEvaluatable(..)
1219 | PredicateKind::ConstEquate(..)
1220 | PredicateKind::TypeWellFormedFromEnv(..) => None,
1225 /// Represents the bounds declared on a particular set of type
1226 /// parameters. Should eventually be generalized into a flag list of
1227 /// where-clauses. You can obtain an `InstantiatedPredicates` list from a
1228 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1229 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1230 /// the `GenericPredicates` are expressed in terms of the bound type
1231 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1232 /// represented a set of bounds for some particular instantiation,
1233 /// meaning that the generic parameters have been substituted with
1237 /// ```ignore (illustrative)
1238 /// struct Foo<T, U: Bar<T>> { ... }
1240 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1241 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1242 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1243 /// [usize:Bar<isize>]]`.
1244 #[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
1245 pub struct InstantiatedPredicates<'tcx> {
1246 pub predicates: Vec<Predicate<'tcx>>,
1247 pub spans: Vec<Span>,
1250 impl<'tcx> InstantiatedPredicates<'tcx> {
1251 pub fn empty() -> InstantiatedPredicates<'tcx> {
1252 InstantiatedPredicates { predicates: vec![], spans: vec![] }
1255 pub fn is_empty(&self) -> bool {
1256 self.predicates.is_empty()
1260 #[derive(Copy, Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable, Lift)]
1261 #[derive(TypeFoldable, TypeVisitable)]
1262 pub struct OpaqueTypeKey<'tcx> {
1263 pub def_id: LocalDefId,
1264 pub substs: SubstsRef<'tcx>,
1267 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)]
1268 pub struct OpaqueHiddenType<'tcx> {
1269 /// The span of this particular definition of the opaque type. So
1272 /// ```ignore (incomplete snippet)
1273 /// type Foo = impl Baz;
1274 /// fn bar() -> Foo {
1275 /// // ^^^ This is the span we are looking for!
1279 /// In cases where the fn returns `(impl Trait, impl Trait)` or
1280 /// other such combinations, the result is currently
1281 /// over-approximated, but better than nothing.
1284 /// The type variable that represents the value of the opaque type
1285 /// that we require. In other words, after we compile this function,
1286 /// we will be created a constraint like:
1287 /// ```ignore (pseudo-rust)
1290 /// where `?C` is the value of this type variable. =) It may
1291 /// naturally refer to the type and lifetime parameters in scope
1292 /// in this function, though ultimately it should only reference
1293 /// those that are arguments to `Foo` in the constraint above. (In
1294 /// other words, `?C` should not include `'b`, even though it's a
1295 /// lifetime parameter on `foo`.)
1299 impl<'tcx> OpaqueHiddenType<'tcx> {
1300 pub fn report_mismatch(&self, other: &Self, tcx: TyCtxt<'tcx>) {
1301 // Found different concrete types for the opaque type.
1302 let sub_diag = if self.span == other.span {
1303 TypeMismatchReason::ConflictType { span: self.span }
1305 TypeMismatchReason::PreviousUse { span: self.span }
1307 tcx.sess.emit_err(OpaqueHiddenTypeMismatch {
1310 other_span: other.span,
1315 #[instrument(level = "debug", skip(tcx), ret)]
1316 pub fn remap_generic_params_to_declaration_params(
1318 opaque_type_key: OpaqueTypeKey<'tcx>,
1320 // typeck errors have subpar spans for opaque types, so delay error reporting until borrowck.
1321 ignore_errors: bool,
1322 origin: OpaqueTyOrigin,
1324 let OpaqueTypeKey { def_id, substs } = opaque_type_key;
1326 // Use substs to build up a reverse map from regions to their
1327 // identity mappings. This is necessary because of `impl
1328 // Trait` lifetimes are computed by replacing existing
1329 // lifetimes with 'static and remapping only those used in the
1330 // `impl Trait` return type, resulting in the parameters
1332 let id_substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
1335 let map = substs.iter().zip(id_substs);
1337 let map: FxHashMap<GenericArg<'tcx>, GenericArg<'tcx>> = match origin {
1338 // HACK: The HIR lowering for async fn does not generate
1339 // any `+ Captures<'x>` bounds for the `impl Future<...>`, so all async fns with lifetimes
1340 // would now fail to compile. We should probably just make hir lowering fill this in properly.
1341 OpaqueTyOrigin::AsyncFn(_) => map.collect(),
1342 OpaqueTyOrigin::FnReturn(_) | OpaqueTyOrigin::TyAlias => {
1343 // Opaque types may only use regions that are bound. So for
1345 // type Foo<'a, 'b, 'c> = impl Trait<'a> + 'b;
1347 // we may not use `'c` in the hidden type.
1348 struct OpaqueTypeLifetimeCollector<'tcx> {
1349 lifetimes: FxHashSet<ty::Region<'tcx>>,
1352 impl<'tcx> ty::TypeVisitor<'tcx> for OpaqueTypeLifetimeCollector<'tcx> {
1353 fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
1354 self.lifetimes.insert(r);
1355 r.super_visit_with(self)
1359 let mut collector = OpaqueTypeLifetimeCollector { lifetimes: Default::default() };
1361 for pred in tcx.bound_explicit_item_bounds(def_id.to_def_id()).transpose_iter() {
1362 let pred = pred.map_bound(|(pred, _)| *pred).subst(tcx, id_substs);
1364 trace!(pred=?pred.kind());
1366 // We only ignore opaque type substs if the opaque type is the outermost type.
1367 // The opaque type may be nested within itself via recursion in e.g.
1368 // type Foo<'a> = impl PartialEq<Foo<'a>>;
1369 // which thus mentions `'a` and should thus accept hidden types that borrow 'a
1370 // instead of requiring an additional `+ 'a`.
1371 match pred.kind().skip_binder() {
1372 ty::PredicateKind::Trait(TraitPredicate {
1373 trait_ref: ty::TraitRef { def_id: _, substs },
1378 for subst in &substs[1..] {
1379 subst.visit_with(&mut collector);
1382 ty::PredicateKind::Projection(ty::ProjectionPredicate {
1383 projection_ty: ty::ProjectionTy { substs, item_def_id: _ },
1386 for subst in &substs[1..] {
1387 subst.visit_with(&mut collector);
1389 term.visit_with(&mut collector);
1392 pred.visit_with(&mut collector);
1396 let lifetimes = collector.lifetimes;
1398 map.filter(|(_, v)| {
1399 let ty::GenericArgKind::Lifetime(lt) = v.unpack() else {
1402 lifetimes.contains(<)
1407 debug!("map = {:#?}", map);
1409 // Convert the type from the function into a type valid outside
1410 // the function, by replacing invalid regions with 'static,
1411 // after producing an error for each of them.
1412 self.fold_with(&mut opaque_types::ReverseMapper::new(tcx, map, self.span, ignore_errors))
1416 /// The "placeholder index" fully defines a placeholder region, type, or const. Placeholders are
1417 /// identified by both a universe, as well as a name residing within that universe. Distinct bound
1418 /// regions/types/consts within the same universe simply have an unknown relationship to one
1420 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
1421 #[derive(HashStable, TyEncodable, TyDecodable)]
1422 pub struct Placeholder<T> {
1423 pub universe: UniverseIndex,
1427 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
1429 pub type PlaceholderType = Placeholder<BoundVar>;
1431 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1432 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]
1433 pub struct BoundConst<'tcx> {
1438 pub type PlaceholderConst<'tcx> = Placeholder<BoundVar>;
1440 /// A `DefId` which, in case it is a const argument, is potentially bundled with
1441 /// the `DefId` of the generic parameter it instantiates.
1443 /// This is used to avoid calls to `type_of` for const arguments during typeck
1444 /// which cause cycle errors.
1449 /// fn foo<const N: usize>(&self) -> [u8; N] { [0; N] }
1450 /// // ^ const parameter
1454 /// fn foo<const M: u8>(&self) -> usize { 42 }
1455 /// // ^ const parameter
1460 /// let _b = a.foo::<{ 3 + 7 }>();
1461 /// // ^^^^^^^^^ const argument
1465 /// Let's look at the call `a.foo::<{ 3 + 7 }>()` here. We do not know
1466 /// which `foo` is used until we know the type of `a`.
1468 /// We only know the type of `a` once we are inside of `typeck(main)`.
1469 /// We also end up normalizing the type of `_b` during `typeck(main)` which
1470 /// requires us to evaluate the const argument.
1472 /// To evaluate that const argument we need to know its type,
1473 /// which we would get using `type_of(const_arg)`. This requires us to
1474 /// resolve `foo` as it can be either `usize` or `u8` in this example.
1475 /// However, resolving `foo` once again requires `typeck(main)` to get the type of `a`,
1476 /// which results in a cycle.
1478 /// In short we must not call `type_of(const_arg)` during `typeck(main)`.
1480 /// When first creating the `ty::Const` of the const argument inside of `typeck` we have
1481 /// already resolved `foo` so we know which const parameter this argument instantiates.
1482 /// This means that we also know the expected result of `type_of(const_arg)` even if we
1483 /// aren't allowed to call that query: it is equal to `type_of(const_param)` which is
1484 /// trivial to compute.
1486 /// If we now want to use that constant in a place which potentially needs its type
1487 /// we also pass the type of its `const_param`. This is the point of `WithOptConstParam`,
1488 /// except that instead of a `Ty` we bundle the `DefId` of the const parameter.
1489 /// Meaning that we need to use `type_of(const_param_did)` if `const_param_did` is `Some`
1490 /// to get the type of `did`.
1491 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift, TyEncodable, TyDecodable)]
1492 #[derive(PartialEq, Eq, PartialOrd, Ord)]
1493 #[derive(Hash, HashStable)]
1494 pub struct WithOptConstParam<T> {
1496 /// The `DefId` of the corresponding generic parameter in case `did` is
1497 /// a const argument.
1499 /// Note that even if `did` is a const argument, this may still be `None`.
1500 /// All queries taking `WithOptConstParam` start by calling `tcx.opt_const_param_of(def.did)`
1501 /// to potentially update `param_did` in the case it is `None`.
1502 pub const_param_did: Option<DefId>,
1505 impl<T> WithOptConstParam<T> {
1506 /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`.
1508 pub fn unknown(did: T) -> WithOptConstParam<T> {
1509 WithOptConstParam { did, const_param_did: None }
1513 impl WithOptConstParam<LocalDefId> {
1514 /// Returns `Some((did, param_did))` if `def_id` is a const argument,
1515 /// `None` otherwise.
1517 pub fn try_lookup(did: LocalDefId, tcx: TyCtxt<'_>) -> Option<(LocalDefId, DefId)> {
1518 tcx.opt_const_param_of(did).map(|param_did| (did, param_did))
1521 /// In case `self` is unknown but `self.did` is a const argument, this returns
1522 /// a `WithOptConstParam` with the correct `const_param_did`.
1524 pub fn try_upgrade(self, tcx: TyCtxt<'_>) -> Option<WithOptConstParam<LocalDefId>> {
1525 if self.const_param_did.is_none() {
1526 if let const_param_did @ Some(_) = tcx.opt_const_param_of(self.did) {
1527 return Some(WithOptConstParam { did: self.did, const_param_did });
1534 pub fn to_global(self) -> WithOptConstParam<DefId> {
1535 WithOptConstParam { did: self.did.to_def_id(), const_param_did: self.const_param_did }
1538 pub fn def_id_for_type_of(self) -> DefId {
1539 if let Some(did) = self.const_param_did { did } else { self.did.to_def_id() }
1543 impl WithOptConstParam<DefId> {
1544 pub fn as_local(self) -> Option<WithOptConstParam<LocalDefId>> {
1547 .map(|did| WithOptConstParam { did, const_param_did: self.const_param_did })
1550 pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)> {
1551 if let Some(param_did) = self.const_param_did {
1552 if let Some(did) = self.did.as_local() {
1553 return Some((did, param_did));
1560 pub fn is_local(self) -> bool {
1564 pub fn def_id_for_type_of(self) -> DefId {
1565 self.const_param_did.unwrap_or(self.did)
1569 /// When type checking, we use the `ParamEnv` to track
1570 /// details about the set of where-clauses that are in scope at this
1571 /// particular point.
1572 #[derive(Copy, Clone, Hash, PartialEq, Eq)]
1573 pub struct ParamEnv<'tcx> {
1574 /// This packs both caller bounds and the reveal enum into one pointer.
1576 /// Caller bounds are `Obligation`s that the caller must satisfy. This is
1577 /// basically the set of bounds on the in-scope type parameters, translated
1578 /// into `Obligation`s, and elaborated and normalized.
1580 /// Use the `caller_bounds()` method to access.
1582 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1583 /// want `Reveal::All`.
1585 /// Note: This is packed, use the reveal() method to access it.
1586 packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, ParamTag, true>,
1589 #[derive(Copy, Clone)]
1591 reveal: traits::Reveal,
1592 constness: hir::Constness,
1595 unsafe impl rustc_data_structures::tagged_ptr::Tag for ParamTag {
1596 const BITS: usize = 2;
1598 fn into_usize(self) -> usize {
1600 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst } => 0,
1601 Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst } => 1,
1602 Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const } => 2,
1603 Self { reveal: traits::Reveal::All, constness: hir::Constness::Const } => 3,
1607 unsafe fn from_usize(ptr: usize) -> Self {
1609 0 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst },
1610 1 => Self { reveal: traits::Reveal::All, constness: hir::Constness::NotConst },
1611 2 => Self { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const },
1612 3 => Self { reveal: traits::Reveal::All, constness: hir::Constness::Const },
1613 _ => std::hint::unreachable_unchecked(),
1618 impl<'tcx> fmt::Debug for ParamEnv<'tcx> {
1619 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1620 f.debug_struct("ParamEnv")
1621 .field("caller_bounds", &self.caller_bounds())
1622 .field("reveal", &self.reveal())
1623 .field("constness", &self.constness())
1628 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx> {
1629 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1630 self.caller_bounds().hash_stable(hcx, hasher);
1631 self.reveal().hash_stable(hcx, hasher);
1632 self.constness().hash_stable(hcx, hasher);
1636 impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
1637 fn try_fold_with<F: ty::fold::FallibleTypeFolder<'tcx>>(
1640 ) -> Result<Self, F::Error> {
1642 self.caller_bounds().try_fold_with(folder)?,
1643 self.reveal().try_fold_with(folder)?,
1649 impl<'tcx> TypeVisitable<'tcx> for ParamEnv<'tcx> {
1650 fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
1651 self.caller_bounds().visit_with(visitor)?;
1652 self.reveal().visit_with(visitor)
1656 impl<'tcx> ParamEnv<'tcx> {
1657 /// Construct a trait environment suitable for contexts where
1658 /// there are no where-clauses in scope. Hidden types (like `impl
1659 /// Trait`) are left hidden, so this is suitable for ordinary
1662 pub fn empty() -> Self {
1663 Self::new(List::empty(), Reveal::UserFacing, hir::Constness::NotConst)
1667 pub fn caller_bounds(self) -> &'tcx List<Predicate<'tcx>> {
1668 self.packed.pointer()
1672 pub fn reveal(self) -> traits::Reveal {
1673 self.packed.tag().reveal
1677 pub fn constness(self) -> hir::Constness {
1678 self.packed.tag().constness
1682 pub fn is_const(self) -> bool {
1683 self.packed.tag().constness == hir::Constness::Const
1686 /// Construct a trait environment with no where-clauses in scope
1687 /// where the values of all `impl Trait` and other hidden types
1688 /// are revealed. This is suitable for monomorphized, post-typeck
1689 /// environments like codegen or doing optimizations.
1691 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1692 /// or invoke `param_env.with_reveal_all()`.
1694 pub fn reveal_all() -> Self {
1695 Self::new(List::empty(), Reveal::All, hir::Constness::NotConst)
1698 /// Construct a trait environment with the given set of predicates.
1701 caller_bounds: &'tcx List<Predicate<'tcx>>,
1703 constness: hir::Constness,
1705 ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, ParamTag { reveal, constness }) }
1708 pub fn with_user_facing(mut self) -> Self {
1709 self.packed.set_tag(ParamTag { reveal: Reveal::UserFacing, ..self.packed.tag() });
1714 pub fn with_constness(mut self, constness: hir::Constness) -> Self {
1715 self.packed.set_tag(ParamTag { constness, ..self.packed.tag() });
1720 pub fn with_const(mut self) -> Self {
1721 self.packed.set_tag(ParamTag { constness: hir::Constness::Const, ..self.packed.tag() });
1726 pub fn without_const(mut self) -> Self {
1727 self.packed.set_tag(ParamTag { constness: hir::Constness::NotConst, ..self.packed.tag() });
1732 pub fn remap_constness_with(&mut self, mut constness: ty::BoundConstness) {
1733 *self = self.with_constness(constness.and(self.constness()))
1736 /// Returns a new parameter environment with the same clauses, but
1737 /// which "reveals" the true results of projections in all cases
1738 /// (even for associated types that are specializable). This is
1739 /// the desired behavior during codegen and certain other special
1740 /// contexts; normally though we want to use `Reveal::UserFacing`,
1741 /// which is the default.
1742 /// All opaque types in the caller_bounds of the `ParamEnv`
1743 /// will be normalized to their underlying types.
1744 /// See PR #65989 and issue #65918 for more details
1745 pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self {
1746 if self.packed.tag().reveal == traits::Reveal::All {
1751 tcx.normalize_opaque_types(self.caller_bounds()),
1757 /// Returns this same environment but with no caller bounds.
1759 pub fn without_caller_bounds(self) -> Self {
1760 Self::new(List::empty(), self.reveal(), self.constness())
1763 /// Creates a suitable environment in which to perform trait
1764 /// queries on the given value. When type-checking, this is simply
1765 /// the pair of the environment plus value. But when reveal is set to
1766 /// All, then if `value` does not reference any type parameters, we will
1767 /// pair it with the empty environment. This improves caching and is generally
1770 /// N.B., we preserve the environment when type-checking because it
1771 /// is possible for the user to have wacky where-clauses like
1772 /// `where Box<u32>: Copy`, which are clearly never
1773 /// satisfiable. We generally want to behave as if they were true,
1774 /// although the surrounding function is never reachable.
1775 pub fn and<T: TypeVisitable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1776 match self.reveal() {
1777 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1780 if value.is_global() {
1781 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1783 ParamEnvAnd { param_env: self, value }
1790 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
1791 // the constness of trait bounds is being propagated correctly.
1792 impl<'tcx> PolyTraitRef<'tcx> {
1794 pub fn with_constness(self, constness: BoundConstness) -> PolyTraitPredicate<'tcx> {
1795 self.map_bound(|trait_ref| ty::TraitPredicate {
1798 polarity: ty::ImplPolarity::Positive,
1803 pub fn without_const(self) -> PolyTraitPredicate<'tcx> {
1804 self.with_constness(BoundConstness::NotConst)
1808 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
1809 #[derive(HashStable, Lift)]
1810 pub struct ParamEnvAnd<'tcx, T> {
1811 pub param_env: ParamEnv<'tcx>,
1815 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1816 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1817 (self.param_env, self.value)
1821 pub fn without_const(mut self) -> Self {
1822 self.param_env = self.param_env.without_const();
1827 #[derive(Copy, Clone, Debug, HashStable, Encodable, Decodable)]
1828 pub struct Destructor {
1829 /// The `DefId` of the destructor method
1831 /// The constness of the destructor method
1832 pub constness: hir::Constness,
1836 #[derive(HashStable, TyEncodable, TyDecodable)]
1837 pub struct VariantFlags: u32 {
1838 const NO_VARIANT_FLAGS = 0;
1839 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1840 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1841 /// Indicates whether this variant was obtained as part of recovering from
1842 /// a syntactic error. May be incomplete or bogus.
1843 const IS_RECOVERED = 1 << 1;
1847 /// Definition of a variant -- a struct's fields or an enum variant.
1848 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
1849 pub struct VariantDef {
1850 /// `DefId` that identifies the variant itself.
1851 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1853 /// `DefId` that identifies the variant's constructor.
1854 /// If this variant is a struct variant, then this is `None`.
1855 pub ctor_def_id: Option<DefId>,
1856 /// Variant or struct name.
1858 /// Discriminant of this variant.
1859 pub discr: VariantDiscr,
1860 /// Fields of this variant.
1861 pub fields: Vec<FieldDef>,
1862 /// Type of constructor of variant.
1863 pub ctor_kind: CtorKind,
1864 /// Flags of the variant (e.g. is field list non-exhaustive)?
1865 flags: VariantFlags,
1869 /// Creates a new `VariantDef`.
1871 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1872 /// represents an enum variant).
1874 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1875 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1877 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1878 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1879 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1880 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1881 /// built-in trait), and we do not want to load attributes twice.
1883 /// If someone speeds up attribute loading to not be a performance concern, they can
1884 /// remove this hack and use the constructor `DefId` everywhere.
1887 variant_did: Option<DefId>,
1888 ctor_def_id: Option<DefId>,
1889 discr: VariantDiscr,
1890 fields: Vec<FieldDef>,
1891 ctor_kind: CtorKind,
1895 is_field_list_non_exhaustive: bool,
1898 "VariantDef::new(name = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1899 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1900 name, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1903 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1904 if is_field_list_non_exhaustive {
1905 flags |= VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1909 flags |= VariantFlags::IS_RECOVERED;
1913 def_id: variant_did.unwrap_or(parent_did),
1923 /// Is this field list non-exhaustive?
1925 pub fn is_field_list_non_exhaustive(&self) -> bool {
1926 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1929 /// Was this variant obtained as part of recovering from a syntactic error?
1931 pub fn is_recovered(&self) -> bool {
1932 self.flags.intersects(VariantFlags::IS_RECOVERED)
1935 /// Computes the `Ident` of this variant by looking up the `Span`
1936 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
1937 Ident::new(self.name, tcx.def_ident_span(self.def_id).unwrap())
1941 impl PartialEq for VariantDef {
1943 fn eq(&self, other: &Self) -> bool {
1944 // There should be only one `VariantDef` for each `def_id`, therefore
1945 // it is fine to implement `PartialEq` only based on `def_id`.
1947 // Below, we exhaustively destructure `self` and `other` so that if the
1948 // definition of `VariantDef` changes, a compile-error will be produced,
1949 // reminding us to revisit this assumption.
1971 lhs_def_id == rhs_def_id
1975 impl Eq for VariantDef {}
1977 impl Hash for VariantDef {
1979 fn hash<H: Hasher>(&self, s: &mut H) {
1980 // There should be only one `VariantDef` for each `def_id`, therefore
1981 // it is fine to implement `Hash` only based on `def_id`.
1983 // Below, we exhaustively destructure `self` so that if the definition
1984 // of `VariantDef` changes, a compile-error will be produced, reminding
1985 // us to revisit this assumption.
1987 let Self { def_id, ctor_def_id: _, name: _, discr: _, fields: _, ctor_kind: _, flags: _ } =
1994 #[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
1995 pub enum VariantDiscr {
1996 /// Explicit value for this variant, i.e., `X = 123`.
1997 /// The `DefId` corresponds to the embedded constant.
2000 /// The previous variant's discriminant plus one.
2001 /// For efficiency reasons, the distance from the
2002 /// last `Explicit` discriminant is being stored,
2003 /// or `0` for the first variant, if it has none.
2007 #[derive(Debug, HashStable, TyEncodable, TyDecodable)]
2008 pub struct FieldDef {
2011 pub vis: Visibility<DefId>,
2014 impl PartialEq for FieldDef {
2016 fn eq(&self, other: &Self) -> bool {
2017 // There should be only one `FieldDef` for each `did`, therefore it is
2018 // fine to implement `PartialEq` only based on `did`.
2020 // Below, we exhaustively destructure `self` so that if the definition
2021 // of `FieldDef` changes, a compile-error will be produced, reminding
2022 // us to revisit this assumption.
2024 let Self { did: lhs_did, name: _, vis: _ } = &self;
2026 let Self { did: rhs_did, name: _, vis: _ } = other;
2032 impl Eq for FieldDef {}
2034 impl Hash for FieldDef {
2036 fn hash<H: Hasher>(&self, s: &mut H) {
2037 // There should be only one `FieldDef` for each `did`, therefore it is
2038 // fine to implement `Hash` only based on `did`.
2040 // Below, we exhaustively destructure `self` so that if the definition
2041 // of `FieldDef` changes, a compile-error will be produced, reminding
2042 // us to revisit this assumption.
2044 let Self { did, name: _, vis: _ } = &self;
2051 #[derive(TyEncodable, TyDecodable, Default, HashStable)]
2052 pub struct ReprFlags: u8 {
2053 const IS_C = 1 << 0;
2054 const IS_SIMD = 1 << 1;
2055 const IS_TRANSPARENT = 1 << 2;
2056 // Internal only for now. If true, don't reorder fields.
2057 const IS_LINEAR = 1 << 3;
2058 // If true, the type's layout can be randomized using
2059 // the seed stored in `ReprOptions.layout_seed`
2060 const RANDOMIZE_LAYOUT = 1 << 4;
2061 // Any of these flags being set prevent field reordering optimisation.
2062 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits
2063 | ReprFlags::IS_SIMD.bits
2064 | ReprFlags::IS_LINEAR.bits;
2068 /// Represents the repr options provided by the user,
2069 #[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Default, HashStable)]
2070 pub struct ReprOptions {
2071 pub int: Option<attr::IntType>,
2072 pub align: Option<Align>,
2073 pub pack: Option<Align>,
2074 pub flags: ReprFlags,
2075 /// The seed to be used for randomizing a type's layout
2077 /// Note: This could technically be a `[u8; 16]` (a `u128`) which would
2078 /// be the "most accurate" hash as it'd encompass the item and crate
2079 /// hash without loss, but it does pay the price of being larger.
2080 /// Everything's a tradeoff, a `u64` seed should be sufficient for our
2081 /// purposes (primarily `-Z randomize-layout`)
2082 pub field_shuffle_seed: u64,
2086 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2087 let mut flags = ReprFlags::empty();
2088 let mut size = None;
2089 let mut max_align: Option<Align> = None;
2090 let mut min_pack: Option<Align> = None;
2092 // Generate a deterministically-derived seed from the item's path hash
2093 // to allow for cross-crate compilation to actually work
2094 let mut field_shuffle_seed = tcx.def_path_hash(did).0.to_smaller_hash();
2096 // If the user defined a custom seed for layout randomization, xor the item's
2097 // path hash with the user defined seed, this will allowing determinism while
2098 // still allowing users to further randomize layout generation for e.g. fuzzing
2099 if let Some(user_seed) = tcx.sess.opts.unstable_opts.layout_seed {
2100 field_shuffle_seed ^= user_seed;
2103 for attr in tcx.get_attrs(did, sym::repr) {
2104 for r in attr::parse_repr_attr(&tcx.sess, attr) {
2105 flags.insert(match r {
2106 attr::ReprC => ReprFlags::IS_C,
2107 attr::ReprPacked(pack) => {
2108 let pack = Align::from_bytes(pack as u64).unwrap();
2109 min_pack = Some(if let Some(min_pack) = min_pack {
2116 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2117 attr::ReprSimd => ReprFlags::IS_SIMD,
2118 attr::ReprInt(i) => {
2122 attr::ReprAlign(align) => {
2123 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2130 // If `-Z randomize-layout` was enabled for the type definition then we can
2131 // consider performing layout randomization
2132 if tcx.sess.opts.unstable_opts.randomize_layout {
2133 flags.insert(ReprFlags::RANDOMIZE_LAYOUT);
2136 // This is here instead of layout because the choice must make it into metadata.
2137 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2138 flags.insert(ReprFlags::IS_LINEAR);
2141 Self { int: size, align: max_align, pack: min_pack, flags, field_shuffle_seed }
2145 pub fn simd(&self) -> bool {
2146 self.flags.contains(ReprFlags::IS_SIMD)
2150 pub fn c(&self) -> bool {
2151 self.flags.contains(ReprFlags::IS_C)
2155 pub fn packed(&self) -> bool {
2160 pub fn transparent(&self) -> bool {
2161 self.flags.contains(ReprFlags::IS_TRANSPARENT)
2165 pub fn linear(&self) -> bool {
2166 self.flags.contains(ReprFlags::IS_LINEAR)
2169 /// Returns the discriminant type, given these `repr` options.
2170 /// This must only be called on enums!
2171 pub fn discr_type(&self) -> attr::IntType {
2172 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2175 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2176 /// layout" optimizations, such as representing `Foo<&T>` as a
2178 pub fn inhibit_enum_layout_opt(&self) -> bool {
2179 self.c() || self.int.is_some()
2182 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2183 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2184 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2185 if let Some(pack) = self.pack {
2186 if pack.bytes() == 1 {
2191 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2194 /// Returns `true` if this type is valid for reordering and `-Z randomize-layout`
2195 /// was enabled for its declaration crate
2196 pub fn can_randomize_type_layout(&self) -> bool {
2197 !self.inhibit_struct_field_reordering_opt()
2198 && self.flags.contains(ReprFlags::RANDOMIZE_LAYOUT)
2201 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2202 pub fn inhibit_union_abi_opt(&self) -> bool {
2207 impl<'tcx> FieldDef {
2208 /// Returns the type of this field. The resulting type is not normalized. The `subst` is
2209 /// typically obtained via the second field of [`TyKind::Adt`].
2210 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2211 tcx.bound_type_of(self.did).subst(tcx, subst)
2214 /// Computes the `Ident` of this variant by looking up the `Span`
2215 pub fn ident(&self, tcx: TyCtxt<'_>) -> Ident {
2216 Ident::new(self.name, tcx.def_ident_span(self.did).unwrap())
2220 pub type Attributes<'tcx> = impl Iterator<Item = &'tcx ast::Attribute>;
2221 #[derive(Debug, PartialEq, Eq)]
2222 pub enum ImplOverlapKind {
2223 /// These impls are always allowed to overlap.
2225 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
2228 /// These impls are allowed to overlap, but that raises
2229 /// an issue #33140 future-compatibility warning.
2231 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2232 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2234 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2235 /// that difference, making what reduces to the following set of impls:
2237 /// ```compile_fail,(E0119)
2239 /// impl Trait for dyn Send + Sync {}
2240 /// impl Trait for dyn Sync + Send {}
2243 /// Obviously, once we made these types be identical, that code causes a coherence
2244 /// error and a fairly big headache for us. However, luckily for us, the trait
2245 /// `Trait` used in this case is basically a marker trait, and therefore having
2246 /// overlapping impls for it is sound.
2248 /// To handle this, we basically regard the trait as a marker trait, with an additional
2249 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2250 /// it has the following restrictions:
2252 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2254 /// 2. The trait-ref of both impls must be equal.
2255 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2257 /// 4. Neither of the impls can have any where-clauses.
2259 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2263 impl<'tcx> TyCtxt<'tcx> {
2264 pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> {
2265 self.typeck(self.hir().body_owner_def_id(body))
2268 pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
2269 self.associated_items(id)
2270 .in_definition_order()
2271 .filter(move |item| item.kind == AssocKind::Fn && item.defaultness(self).has_value())
2274 /// Look up the name of a definition across crates. This does not look at HIR.
2275 pub fn opt_item_name(self, def_id: DefId) -> Option<Symbol> {
2276 if let Some(cnum) = def_id.as_crate_root() {
2277 Some(self.crate_name(cnum))
2279 let def_key = self.def_key(def_id);
2280 match def_key.disambiguated_data.data {
2281 // The name of a constructor is that of its parent.
2282 rustc_hir::definitions::DefPathData::Ctor => self
2283 .opt_item_name(DefId { krate: def_id.krate, index: def_key.parent.unwrap() }),
2284 // The name of opaque types only exists in HIR.
2285 rustc_hir::definitions::DefPathData::ImplTrait
2286 if let Some(def_id) = def_id.as_local() =>
2287 self.hir().opt_name(self.hir().local_def_id_to_hir_id(def_id)),
2288 _ => def_key.get_opt_name(),
2293 /// Look up the name of a definition across crates. This does not look at HIR.
2295 /// This method will ICE if the corresponding item does not have a name. In these cases, use
2296 /// [`opt_item_name`] instead.
2298 /// [`opt_item_name`]: Self::opt_item_name
2299 pub fn item_name(self, id: DefId) -> Symbol {
2300 self.opt_item_name(id).unwrap_or_else(|| {
2301 bug!("item_name: no name for {:?}", self.def_path(id));
2305 /// Look up the name and span of a definition.
2307 /// See [`item_name`][Self::item_name] for more information.
2308 pub fn opt_item_ident(self, def_id: DefId) -> Option<Ident> {
2309 let def = self.opt_item_name(def_id)?;
2312 .and_then(|id| self.def_ident_span(id))
2313 .unwrap_or(rustc_span::DUMMY_SP);
2314 Some(Ident::new(def, span))
2317 pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> {
2318 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2319 Some(self.associated_item(def_id))
2325 pub fn field_index(self, hir_id: hir::HirId, typeck_results: &TypeckResults<'_>) -> usize {
2326 typeck_results.field_indices().get(hir_id).cloned().expect("no index for a field")
2329 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2333 .position(|field| self.hygienic_eq(ident, field.ident(self), variant.def_id))
2336 /// Returns `true` if the impls are the same polarity and the trait either
2337 /// has no items or is annotated `#[marker]` and prevents item overrides.
2338 pub fn impls_are_allowed_to_overlap(
2342 ) -> Option<ImplOverlapKind> {
2343 // If either trait impl references an error, they're allowed to overlap,
2344 // as one of them essentially doesn't exist.
2345 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
2346 || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
2348 return Some(ImplOverlapKind::Permitted { marker: false });
2351 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2352 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
2353 // `#[rustc_reservation_impl]` impls don't overlap with anything
2355 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2358 return Some(ImplOverlapKind::Permitted { marker: false });
2360 (ImplPolarity::Positive, ImplPolarity::Negative)
2361 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
2362 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2364 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2369 (ImplPolarity::Positive, ImplPolarity::Positive)
2370 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2373 let is_marker_overlap = {
2374 let is_marker_impl = |def_id: DefId| -> bool {
2375 let trait_ref = self.impl_trait_ref(def_id);
2376 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2378 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2381 if is_marker_overlap {
2383 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2386 Some(ImplOverlapKind::Permitted { marker: true })
2388 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2389 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2390 if self_ty1 == self_ty2 {
2392 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2395 return Some(ImplOverlapKind::Issue33140);
2398 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2399 def_id1, def_id2, self_ty1, self_ty2
2405 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
2410 /// Returns `ty::VariantDef` if `res` refers to a struct,
2411 /// or variant or their constructors, panics otherwise.
2412 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2414 Res::Def(DefKind::Variant, did) => {
2415 let enum_did = self.parent(did);
2416 self.adt_def(enum_did).variant_with_id(did)
2418 Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(),
2419 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2420 let variant_did = self.parent(variant_ctor_did);
2421 let enum_did = self.parent(variant_did);
2422 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2424 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2425 let struct_did = self.parent(ctor_did);
2426 self.adt_def(struct_did).non_enum_variant()
2428 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
2432 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2433 #[instrument(skip(self), level = "debug")]
2434 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
2436 ty::InstanceDef::Item(def) => {
2437 debug!("calling def_kind on def: {:?}", def);
2438 let def_kind = self.def_kind(def.did);
2439 debug!("returned from def_kind: {:?}", def_kind);
2442 | DefKind::Static(..)
2443 | DefKind::AssocConst
2445 | DefKind::AnonConst
2446 | DefKind::InlineConst => self.mir_for_ctfe_opt_const_arg(def),
2447 // If the caller wants `mir_for_ctfe` of a function they should not be using
2448 // `instance_mir`, so we'll assume const fn also wants the optimized version.
2450 assert_eq!(def.const_param_did, None);
2451 self.optimized_mir(def.did)
2455 ty::InstanceDef::VTableShim(..)
2456 | ty::InstanceDef::ReifyShim(..)
2457 | ty::InstanceDef::Intrinsic(..)
2458 | ty::InstanceDef::FnPtrShim(..)
2459 | ty::InstanceDef::Virtual(..)
2460 | ty::InstanceDef::ClosureOnceShim { .. }
2461 | ty::InstanceDef::DropGlue(..)
2462 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance),
2466 // FIXME(@lcnr): Remove this function.
2467 pub fn get_attrs_unchecked(self, did: DefId) -> &'tcx [ast::Attribute] {
2468 if let Some(did) = did.as_local() {
2469 self.hir().attrs(self.hir().local_def_id_to_hir_id(did))
2471 self.item_attrs(did)
2475 /// Gets all attributes with the given name.
2476 pub fn get_attrs(self, did: DefId, attr: Symbol) -> ty::Attributes<'tcx> {
2477 let filter_fn = move |a: &&ast::Attribute| a.has_name(attr);
2478 if let Some(did) = did.as_local() {
2479 self.hir().attrs(self.hir().local_def_id_to_hir_id(did)).iter().filter(filter_fn)
2480 } else if cfg!(debug_assertions) && rustc_feature::is_builtin_only_local(attr) {
2481 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2483 self.item_attrs(did).iter().filter(filter_fn)
2487 pub fn get_attr(self, did: DefId, attr: Symbol) -> Option<&'tcx ast::Attribute> {
2488 if cfg!(debug_assertions) && !rustc_feature::is_valid_for_get_attr(attr) {
2489 bug!("get_attr: unexpected called with DefId `{:?}`, attr `{:?}`", did, attr);
2491 self.get_attrs(did, attr).next()
2495 /// Determines whether an item is annotated with an attribute.
2496 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
2497 if cfg!(debug_assertions) && !did.is_local() && rustc_feature::is_builtin_only_local(attr) {
2498 bug!("tried to access the `only_local` attribute `{}` from an extern crate", attr);
2500 self.get_attrs(did, attr).next().is_some()
2504 /// Returns `true` if this is an `auto trait`.
2505 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2506 self.trait_def(trait_def_id).has_auto_impl
2509 pub fn trait_is_coinductive(self, trait_def_id: DefId) -> bool {
2510 self.trait_is_auto(trait_def_id) || self.lang_items().sized_trait() == Some(trait_def_id)
2513 /// Returns layout of a generator. Layout might be unavailable if the
2514 /// generator is tainted by errors.
2515 pub fn generator_layout(self, def_id: DefId) -> Option<&'tcx GeneratorLayout<'tcx>> {
2516 self.optimized_mir(def_id).generator_layout()
2519 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
2520 /// If it implements no trait, returns `None`.
2521 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2522 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2525 /// If the given `DefId` describes an item belonging to a trait,
2526 /// returns the `DefId` of the trait that the trait item belongs to;
2527 /// otherwise, returns `None`.
2528 pub fn trait_of_item(self, def_id: DefId) -> Option<DefId> {
2529 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2530 let parent = self.parent(def_id);
2531 if let DefKind::Trait | DefKind::TraitAlias = self.def_kind(parent) {
2532 return Some(parent);
2538 /// If the given `DefId` describes a method belonging to an impl, returns the
2539 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
2540 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2541 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
2542 let parent = self.parent(def_id);
2543 if let DefKind::Impl = self.def_kind(parent) {
2544 return Some(parent);
2550 /// If the given `DefId` belongs to a trait that was automatically derived, returns `true`.
2551 pub fn is_builtin_derive(self, def_id: DefId) -> bool {
2552 self.has_attr(def_id, sym::automatically_derived)
2555 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2556 /// with the name of the crate containing the impl.
2557 pub fn span_of_impl(self, impl_def_id: DefId) -> Result<Span, Symbol> {
2558 if let Some(impl_def_id) = impl_def_id.as_local() {
2559 Ok(self.def_span(impl_def_id))
2561 Err(self.crate_name(impl_def_id.krate))
2565 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
2566 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2567 /// definition's parent/scope to perform comparison.
2568 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2569 // We could use `Ident::eq` here, but we deliberately don't. The name
2570 // comparison fails frequently, and we want to avoid the expensive
2571 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
2572 use_name.name == def_name.name
2576 .hygienic_eq(def_name.span.ctxt(), self.expn_that_defined(def_parent_def_id))
2579 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
2580 ident.span.normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope));
2584 pub fn adjust_ident_and_get_scope(
2589 ) -> (Ident, DefId) {
2592 .normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope))
2593 .and_then(|actual_expansion| actual_expansion.expn_data().parent_module)
2594 .unwrap_or_else(|| self.parent_module(block).to_def_id());
2598 /// Returns `true` if the debuginfo for `span` should be collapsed to the outermost expansion
2599 /// site. Only applies when `Span` is the result of macro expansion.
2601 /// - If the `collapse_debuginfo` feature is enabled then debuginfo is not collapsed by default
2602 /// and only when a macro definition is annotated with `#[collapse_debuginfo]`.
2603 /// - If `collapse_debuginfo` is not enabled, then debuginfo is collapsed by default.
2605 /// When `-Zdebug-macros` is provided then debuginfo will never be collapsed.
2606 pub fn should_collapse_debuginfo(self, span: Span) -> bool {
2607 !self.sess.opts.unstable_opts.debug_macros
2608 && if self.features().collapse_debuginfo {
2609 span.in_macro_expansion_with_collapse_debuginfo()
2611 // Inlined spans should not be collapsed as that leads to all of the
2612 // inlined code being attributed to the inline callsite.
2613 span.from_expansion() && !span.is_inlined()
2617 pub fn is_object_safe(self, key: DefId) -> bool {
2618 self.object_safety_violations(key).is_empty()
2622 pub fn is_const_fn_raw(self, def_id: DefId) -> bool {
2623 matches!(self.def_kind(def_id), DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(..))
2624 && self.constness(def_id) == hir::Constness::Const
2628 pub fn is_const_default_method(self, def_id: DefId) -> bool {
2629 matches!(self.trait_of_item(def_id), Some(trait_id) if self.has_attr(trait_id, sym::const_trait))
2632 pub fn impl_trait_in_trait_parent(self, mut def_id: DefId) -> DefId {
2633 while let def_kind = self.def_kind(def_id) && def_kind != DefKind::AssocFn {
2634 debug_assert_eq!(def_kind, DefKind::ImplTraitPlaceholder);
2635 def_id = self.parent(def_id);
2641 /// Yields the parent function's `LocalDefId` if `def_id` is an `impl Trait` definition.
2642 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<LocalDefId> {
2643 let def_id = def_id.as_local()?;
2644 if let Node::Item(item) = tcx.hir().get_by_def_id(def_id) {
2645 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
2646 return match opaque_ty.origin {
2647 hir::OpaqueTyOrigin::FnReturn(parent) | hir::OpaqueTyOrigin::AsyncFn(parent) => {
2650 hir::OpaqueTyOrigin::TyAlias => None,
2657 pub fn int_ty(ity: ast::IntTy) -> IntTy {
2659 ast::IntTy::Isize => IntTy::Isize,
2660 ast::IntTy::I8 => IntTy::I8,
2661 ast::IntTy::I16 => IntTy::I16,
2662 ast::IntTy::I32 => IntTy::I32,
2663 ast::IntTy::I64 => IntTy::I64,
2664 ast::IntTy::I128 => IntTy::I128,
2668 pub fn uint_ty(uty: ast::UintTy) -> UintTy {
2670 ast::UintTy::Usize => UintTy::Usize,
2671 ast::UintTy::U8 => UintTy::U8,
2672 ast::UintTy::U16 => UintTy::U16,
2673 ast::UintTy::U32 => UintTy::U32,
2674 ast::UintTy::U64 => UintTy::U64,
2675 ast::UintTy::U128 => UintTy::U128,
2679 pub fn float_ty(fty: ast::FloatTy) -> FloatTy {
2681 ast::FloatTy::F32 => FloatTy::F32,
2682 ast::FloatTy::F64 => FloatTy::F64,
2686 pub fn ast_int_ty(ity: IntTy) -> ast::IntTy {
2688 IntTy::Isize => ast::IntTy::Isize,
2689 IntTy::I8 => ast::IntTy::I8,
2690 IntTy::I16 => ast::IntTy::I16,
2691 IntTy::I32 => ast::IntTy::I32,
2692 IntTy::I64 => ast::IntTy::I64,
2693 IntTy::I128 => ast::IntTy::I128,
2697 pub fn ast_uint_ty(uty: UintTy) -> ast::UintTy {
2699 UintTy::Usize => ast::UintTy::Usize,
2700 UintTy::U8 => ast::UintTy::U8,
2701 UintTy::U16 => ast::UintTy::U16,
2702 UintTy::U32 => ast::UintTy::U32,
2703 UintTy::U64 => ast::UintTy::U64,
2704 UintTy::U128 => ast::UintTy::U128,
2708 pub fn provide(providers: &mut ty::query::Providers) {
2709 closure::provide(providers);
2710 context::provide(providers);
2711 erase_regions::provide(providers);
2712 inhabitedness::provide(providers);
2713 util::provide(providers);
2714 print::provide(providers);
2715 super::util::bug::provide(providers);
2716 super::middle::provide(providers);
2717 *providers = ty::query::Providers {
2718 trait_impls_of: trait_def::trait_impls_of_provider,
2719 incoherent_impls: trait_def::incoherent_impls_provider,
2720 const_param_default: consts::const_param_default,
2721 vtable_allocation: vtable::vtable_allocation_provider,
2726 /// A map for the local crate mapping each type to a vector of its
2727 /// inherent impls. This is not meant to be used outside of coherence;
2728 /// rather, you should request the vector for a specific type via
2729 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2730 /// (constructing this map requires touching the entire crate).
2731 #[derive(Clone, Debug, Default, HashStable)]
2732 pub struct CrateInherentImpls {
2733 pub inherent_impls: LocalDefIdMap<Vec<DefId>>,
2734 pub incoherent_impls: FxHashMap<SimplifiedType, Vec<LocalDefId>>,
2737 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]
2738 pub struct SymbolName<'tcx> {
2739 /// `&str` gives a consistent ordering, which ensures reproducible builds.
2740 pub name: &'tcx str,
2743 impl<'tcx> SymbolName<'tcx> {
2744 pub fn new(tcx: TyCtxt<'tcx>, name: &str) -> SymbolName<'tcx> {
2746 name: unsafe { str::from_utf8_unchecked(tcx.arena.alloc_slice(name.as_bytes())) },
2751 impl<'tcx> fmt::Display for SymbolName<'tcx> {
2752 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2753 fmt::Display::fmt(&self.name, fmt)
2757 impl<'tcx> fmt::Debug for SymbolName<'tcx> {
2758 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2759 fmt::Display::fmt(&self.name, fmt)
2763 #[derive(Debug, Default, Copy, Clone)]
2764 pub struct FoundRelationships {
2765 /// This is true if we identified that this Ty (`?T`) is found in a `?T: Foo`
2766 /// obligation, where:
2768 /// * `Foo` is not `Sized`
2769 /// * `(): Foo` may be satisfied
2770 pub self_in_trait: bool,
2771 /// This is true if we identified that this Ty (`?T`) is found in a `<_ as
2772 /// _>::AssocType = ?T`
2776 /// The constituent parts of a type level constant of kind ADT or array.
2777 #[derive(Copy, Clone, Debug, HashStable)]
2778 pub struct DestructuredConst<'tcx> {
2779 pub variant: Option<VariantIdx>,
2780 pub fields: &'tcx [ty::Const<'tcx>],
2783 // Some types are used a lot. Make sure they don't unintentionally get bigger.
2784 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2787 use rustc_data_structures::static_assert_size;
2788 // tidy-alphabetical-start
2789 static_assert_size!(PredicateS<'_>, 48);
2790 static_assert_size!(TyS<'_>, 40);
2791 static_assert_size!(WithStableHash<TyS<'_>>, 56);
2792 // tidy-alphabetical-end