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 ructc-dev-guide.
10 //! ["The `ty` module: representing types"]: https://rustc-dev-guide.rust-lang.org/ty.html
12 pub use self::fold::{TypeFoldable, TypeFolder, TypeVisitor};
13 pub use self::AssocItemContainer::*;
14 pub use self::BorrowKind::*;
15 pub use self::IntVarValue::*;
16 pub use self::Variance::*;
22 use crate::hir::exports::ExportMap;
23 use crate::ich::StableHashingContext;
24 use crate::middle::cstore::CrateStoreDyn;
25 use crate::mir::{Body, GeneratorLayout};
26 use crate::traits::{self, Reveal};
28 use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
29 use crate::ty::util::Discr;
31 use rustc_attr as attr;
32 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
33 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
34 use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
36 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
37 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalDefIdMap, CRATE_DEF_INDEX};
39 use rustc_macros::HashStable;
40 use rustc_span::symbol::{kw, Ident, Symbol};
42 use rustc_target::abi::Align;
44 use std::cmp::Ordering;
45 use std::collections::BTreeMap;
46 use std::hash::{Hash, Hasher};
47 use std::ops::ControlFlow;
48 use std::{fmt, ptr, str};
50 pub use crate::ty::diagnostics::*;
51 pub use rustc_type_ir::InferTy::*;
52 pub use rustc_type_ir::*;
54 pub use self::binding::BindingMode;
55 pub use self::binding::BindingMode::*;
56 pub use self::closure::{
57 is_ancestor_or_same_capture, place_to_string_for_capture, BorrowKind, CaptureInfo,
58 CapturedPlace, ClosureKind, MinCaptureInformationMap, MinCaptureList,
59 RootVariableMinCaptureList, UpvarBorrow, UpvarCapture, UpvarCaptureMap, UpvarId, UpvarListMap,
60 UpvarPath, CAPTURE_STRUCT_LOCAL,
62 pub use self::consts::{Const, ConstInt, ConstKind, InferConst, ScalarInt, Unevaluated, ValTree};
63 pub use self::context::{
64 tls, CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
65 CtxtInterners, DelaySpanBugEmitted, FreeRegionInfo, GeneratorInteriorTypeCause, GlobalCtxt,
66 Lift, OnDiskCache, TyCtxt, TypeckResults, UserType, UserTypeAnnotationIndex,
68 pub use self::instance::{Instance, InstanceDef};
69 pub use self::list::List;
70 pub use self::sty::BoundRegionKind::*;
71 pub use self::sty::RegionKind::*;
72 pub use self::sty::TyKind::*;
74 Binder, BoundRegion, BoundRegionKind, BoundTy, BoundTyKind, BoundVar, BoundVariableKind,
75 CanonicalPolyFnSig, ClosureSubsts, ClosureSubstsParts, ConstVid, EarlyBoundRegion,
76 ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FnSig, FreeRegion, GenSig,
77 GeneratorSubsts, GeneratorSubstsParts, ParamConst, ParamTy, PolyExistentialProjection,
78 PolyExistentialTraitRef, PolyFnSig, PolyGenSig, PolyTraitRef, ProjectionTy, Region, RegionKind,
79 RegionVid, TraitRef, TyKind, TypeAndMut, UpvarSubsts, VarianceDiagInfo, VarianceDiagMutKind,
81 pub use self::trait_def::TraitDef;
92 pub mod inhabitedness;
94 pub mod normalize_erasing_regions;
115 mod structural_impls;
121 pub struct ResolverOutputs {
122 pub definitions: rustc_hir::definitions::Definitions,
123 pub cstore: Box<CrateStoreDyn>,
124 pub visibilities: FxHashMap<LocalDefId, Visibility>,
125 pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
126 pub maybe_unused_trait_imports: FxHashSet<LocalDefId>,
127 pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
128 pub export_map: ExportMap,
129 pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
130 /// Extern prelude entries. The value is `true` if the entry was introduced
131 /// via `extern crate` item and not `--extern` option or compiler built-in.
132 pub extern_prelude: FxHashMap<Symbol, bool>,
133 pub main_def: Option<MainDefinition>,
134 pub trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
135 /// A list of proc macro LocalDefIds, written out in the order in which
136 /// they are declared in the static array generated by proc_macro_harness.
137 pub proc_macros: Vec<LocalDefId>,
138 /// Mapping from ident span to path span for paths that don't exist as written, but that
139 /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
140 pub confused_type_with_std_module: FxHashMap<Span, Span>,
143 #[derive(Clone, Copy, Debug)]
144 pub struct MainDefinition {
145 pub res: Res<ast::NodeId>,
150 impl MainDefinition {
151 pub fn opt_fn_def_id(self) -> Option<DefId> {
152 if let Res::Def(DefKind::Fn, def_id) = self.res { Some(def_id) } else { None }
156 /// The "header" of an impl is everything outside the body: a Self type, a trait
157 /// ref (in the case of a trait impl), and a set of predicates (from the
158 /// bounds / where-clauses).
159 #[derive(Clone, Debug, TypeFoldable)]
160 pub struct ImplHeader<'tcx> {
161 pub impl_def_id: DefId,
162 pub self_ty: Ty<'tcx>,
163 pub trait_ref: Option<TraitRef<'tcx>>,
164 pub predicates: Vec<Predicate<'tcx>>,
167 #[derive(Copy, Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
168 pub enum ImplPolarity {
169 /// `impl Trait for Type`
171 /// `impl !Trait for Type`
173 /// `#[rustc_reservation_impl] impl Trait for Type`
175 /// This is a "stability hack", not a real Rust feature.
176 /// See #64631 for details.
180 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, TyEncodable, TyDecodable, HashStable)]
181 pub enum Visibility {
182 /// Visible everywhere (including in other crates).
184 /// Visible only in the given crate-local module.
186 /// Not visible anywhere in the local crate. This is the visibility of private external items.
190 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
191 pub enum BoundConstness {
194 /// `T: ~const Trait`
196 /// Requires resolving to const only when we are in a const context.
200 impl fmt::Display for BoundConstness {
201 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
203 Self::NotConst => f.write_str("normal"),
204 Self::ConstIfConst => f.write_str("`~const`"),
221 pub struct ClosureSizeProfileData<'tcx> {
222 /// Tuple containing the types of closure captures before the feature `capture_disjoint_fields`
223 pub before_feature_tys: Ty<'tcx>,
224 /// Tuple containing the types of closure captures after the feature `capture_disjoint_fields`
225 pub after_feature_tys: Ty<'tcx>,
228 pub trait DefIdTree: Copy {
229 fn parent(self, id: DefId) -> Option<DefId>;
231 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
232 if descendant.krate != ancestor.krate {
236 while descendant != ancestor {
237 match self.parent(descendant) {
238 Some(parent) => descendant = parent,
239 None => return false,
246 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
247 fn parent(self, id: DefId) -> Option<DefId> {
248 self.def_key(id).parent.map(|index| DefId { index, ..id })
253 pub fn from_hir(visibility: &hir::Visibility<'_>, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
254 match visibility.node {
255 hir::VisibilityKind::Public => Visibility::Public,
256 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
257 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
258 // If there is no resolution, `resolve` will have already reported an error, so
259 // assume that the visibility is public to avoid reporting more privacy errors.
260 Res::Err => Visibility::Public,
261 def => Visibility::Restricted(def.def_id()),
263 hir::VisibilityKind::Inherited => {
264 Visibility::Restricted(tcx.parent_module(id).to_def_id())
269 /// Returns `true` if an item with this visibility is accessible from the given block.
270 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
271 let restriction = match self {
272 // Public items are visible everywhere.
273 Visibility::Public => return true,
274 // Private items from other crates are visible nowhere.
275 Visibility::Invisible => return false,
276 // Restricted items are visible in an arbitrary local module.
277 Visibility::Restricted(other) if other.krate != module.krate => return false,
278 Visibility::Restricted(module) => module,
281 tree.is_descendant_of(module, restriction)
284 /// Returns `true` if this visibility is at least as accessible as the given visibility
285 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
286 let vis_restriction = match vis {
287 Visibility::Public => return self == Visibility::Public,
288 Visibility::Invisible => return true,
289 Visibility::Restricted(module) => module,
292 self.is_accessible_from(vis_restriction, tree)
295 // Returns `true` if this item is visible anywhere in the local crate.
296 pub fn is_visible_locally(self) -> bool {
298 Visibility::Public => true,
299 Visibility::Restricted(def_id) => def_id.is_local(),
300 Visibility::Invisible => false,
305 /// The crate variances map is computed during typeck and contains the
306 /// variance of every item in the local crate. You should not use it
307 /// directly, because to do so will make your pass dependent on the
308 /// HIR of every item in the local crate. Instead, use
309 /// `tcx.variances_of()` to get the variance for a *particular*
311 #[derive(HashStable, Debug)]
312 pub struct CrateVariancesMap<'tcx> {
313 /// For each item with generics, maps to a vector of the variance
314 /// of its generics. If an item has no generics, it will have no
316 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
319 // Contains information needed to resolve types and (in the future) look up
320 // the types of AST nodes.
321 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
322 pub struct CReaderCacheKey {
323 pub cnum: Option<CrateNum>,
327 #[allow(rustc::usage_of_ty_tykind)]
328 pub struct TyS<'tcx> {
329 /// This field shouldn't be used directly and may be removed in the future.
330 /// Use `TyS::kind()` instead.
332 /// This field shouldn't be used directly and may be removed in the future.
333 /// Use `TyS::flags()` instead.
336 /// This is a kind of confusing thing: it stores the smallest
339 /// (a) the binder itself captures nothing but
340 /// (b) all the late-bound things within the type are captured
341 /// by some sub-binder.
343 /// So, for a type without any late-bound things, like `u32`, this
344 /// will be *innermost*, because that is the innermost binder that
345 /// captures nothing. But for a type `&'D u32`, where `'D` is a
346 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
347 /// -- the binder itself does not capture `D`, but `D` is captured
348 /// by an inner binder.
350 /// We call this concept an "exclusive" binder `D` because all
351 /// De Bruijn indices within the type are contained within `0..D`
353 outer_exclusive_binder: ty::DebruijnIndex,
356 impl<'tcx> TyS<'tcx> {
357 /// A constructor used only for internal testing.
358 #[allow(rustc::usage_of_ty_tykind)]
359 pub fn make_for_test(
362 outer_exclusive_binder: ty::DebruijnIndex,
364 TyS { kind, flags, outer_exclusive_binder }
368 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
369 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
370 static_assert_size!(TyS<'_>, 40);
372 impl<'tcx> Ord for TyS<'tcx> {
373 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
374 self.kind().cmp(other.kind())
378 impl<'tcx> PartialOrd for TyS<'tcx> {
379 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
380 Some(self.kind().cmp(other.kind()))
384 impl<'tcx> PartialEq for TyS<'tcx> {
386 fn eq(&self, other: &TyS<'tcx>) -> bool {
390 impl<'tcx> Eq for TyS<'tcx> {}
392 impl<'tcx> Hash for TyS<'tcx> {
393 fn hash<H: Hasher>(&self, s: &mut H) {
394 (self as *const TyS<'_>).hash(s)
398 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
399 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
403 // The other fields just provide fast access to information that is
404 // also contained in `kind`, so no need to hash them.
407 outer_exclusive_binder: _,
410 kind.hash_stable(hcx, hasher);
414 #[rustc_diagnostic_item = "Ty"]
415 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
417 impl ty::EarlyBoundRegion {
418 /// Does this early bound region have a name? Early bound regions normally
419 /// always have names except when using anonymous lifetimes (`'_`).
420 pub fn has_name(&self) -> bool {
421 self.name != kw::UnderscoreLifetime
426 crate struct PredicateInner<'tcx> {
427 kind: Binder<'tcx, PredicateKind<'tcx>>,
429 /// See the comment for the corresponding field of [TyS].
430 outer_exclusive_binder: ty::DebruijnIndex,
433 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
434 static_assert_size!(PredicateInner<'_>, 48);
436 #[derive(Clone, Copy, Lift)]
437 pub struct Predicate<'tcx> {
438 inner: &'tcx PredicateInner<'tcx>,
441 impl<'tcx> PartialEq for Predicate<'tcx> {
442 fn eq(&self, other: &Self) -> bool {
443 // `self.kind` is always interned.
444 ptr::eq(self.inner, other.inner)
448 impl Hash for Predicate<'_> {
449 fn hash<H: Hasher>(&self, s: &mut H) {
450 (self.inner as *const PredicateInner<'_>).hash(s)
454 impl<'tcx> Eq for Predicate<'tcx> {}
456 impl<'tcx> Predicate<'tcx> {
457 /// Gets the inner `Binder<'tcx, PredicateKind<'tcx>>`.
459 pub fn kind(self) -> Binder<'tcx, PredicateKind<'tcx>> {
464 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {
465 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
469 // The other fields just provide fast access to information that is
470 // also contained in `kind`, so no need to hash them.
472 outer_exclusive_binder: _,
475 kind.hash_stable(hcx, hasher);
479 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
480 #[derive(HashStable, TypeFoldable)]
481 pub enum PredicateKind<'tcx> {
482 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
483 /// the `Self` type of the trait reference and `A`, `B`, and `C`
484 /// would be the type parameters.
485 Trait(TraitPredicate<'tcx>),
488 RegionOutlives(RegionOutlivesPredicate<'tcx>),
491 TypeOutlives(TypeOutlivesPredicate<'tcx>),
493 /// `where <T as TraitRef>::Name == X`, approximately.
494 /// See the `ProjectionPredicate` struct for details.
495 Projection(ProjectionPredicate<'tcx>),
497 /// No syntax: `T` well-formed.
498 WellFormed(GenericArg<'tcx>),
500 /// Trait must be object-safe.
503 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
504 /// for some substitutions `...` and `T` being a closure type.
505 /// Satisfied (or refuted) once we know the closure's kind.
506 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
510 /// This obligation is created most often when we have two
511 /// unresolved type variables and hence don't have enough
512 /// information to process the subtyping obligation yet.
513 Subtype(SubtypePredicate<'tcx>),
515 /// `T1` coerced to `T2`
517 /// Like a subtyping obligation, this is created most often
518 /// when we have two unresolved type variables and hence
519 /// don't have enough information to process the coercion
520 /// obligation yet. At the moment, we actually process coercions
521 /// very much like subtyping and don't handle the full coercion
523 Coerce(CoercePredicate<'tcx>),
525 /// Constant initializer must evaluate successfully.
526 ConstEvaluatable(ty::Unevaluated<'tcx, ()>),
528 /// Constants must be equal. The first component is the const that is expected.
529 ConstEquate(&'tcx Const<'tcx>, &'tcx Const<'tcx>),
531 /// Represents a type found in the environment that we can use for implied bounds.
533 /// Only used for Chalk.
534 TypeWellFormedFromEnv(Ty<'tcx>),
537 /// The crate outlives map is computed during typeck and contains the
538 /// outlives of every item in the local crate. You should not use it
539 /// directly, because to do so will make your pass dependent on the
540 /// HIR of every item in the local crate. Instead, use
541 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
543 #[derive(HashStable, Debug)]
544 pub struct CratePredicatesMap<'tcx> {
545 /// For each struct with outlive bounds, maps to a vector of the
546 /// predicate of its outlive bounds. If an item has no outlives
547 /// bounds, it will have no entry.
548 pub predicates: FxHashMap<DefId, &'tcx [(Predicate<'tcx>, Span)]>,
551 impl<'tcx> Predicate<'tcx> {
552 /// Performs a substitution suitable for going from a
553 /// poly-trait-ref to supertraits that must hold if that
554 /// poly-trait-ref holds. This is slightly different from a normal
555 /// substitution in terms of what happens with bound regions. See
556 /// lengthy comment below for details.
557 pub fn subst_supertrait(
560 trait_ref: &ty::PolyTraitRef<'tcx>,
561 ) -> Predicate<'tcx> {
562 // The interaction between HRTB and supertraits is not entirely
563 // obvious. Let me walk you (and myself) through an example.
565 // Let's start with an easy case. Consider two traits:
567 // trait Foo<'a>: Bar<'a,'a> { }
568 // trait Bar<'b,'c> { }
570 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
571 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
572 // knew that `Foo<'x>` (for any 'x) then we also know that
573 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
574 // normal substitution.
576 // In terms of why this is sound, the idea is that whenever there
577 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
578 // holds. So if there is an impl of `T:Foo<'a>` that applies to
579 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
582 // Another example to be careful of is this:
584 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
585 // trait Bar1<'b,'c> { }
587 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
588 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
589 // reason is similar to the previous example: any impl of
590 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
591 // basically we would want to collapse the bound lifetimes from
592 // the input (`trait_ref`) and the supertraits.
594 // To achieve this in practice is fairly straightforward. Let's
595 // consider the more complicated scenario:
597 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
598 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
599 // where both `'x` and `'b` would have a DB index of 1.
600 // The substitution from the input trait-ref is therefore going to be
601 // `'a => 'x` (where `'x` has a DB index of 1).
602 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
603 // early-bound parameter and `'b' is a late-bound parameter with a
605 // - If we replace `'a` with `'x` from the input, it too will have
606 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
607 // just as we wanted.
609 // There is only one catch. If we just apply the substitution `'a
610 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
611 // adjust the DB index because we substituting into a binder (it
612 // tries to be so smart...) resulting in `for<'x> for<'b>
613 // Bar1<'x,'b>` (we have no syntax for this, so use your
614 // imagination). Basically the 'x will have DB index of 2 and 'b
615 // will have DB index of 1. Not quite what we want. So we apply
616 // the substitution to the *contents* of the trait reference,
617 // rather than the trait reference itself (put another way, the
618 // substitution code expects equal binding levels in the values
619 // from the substitution and the value being substituted into, and
620 // this trick achieves that).
622 // Working through the second example:
623 // trait_ref: for<'x> T: Foo1<'^0.0>; substs: [T, '^0.0]
624 // predicate: for<'b> Self: Bar1<'a, '^0.0>; substs: [Self, 'a, '^0.0]
625 // We want to end up with:
626 // for<'x, 'b> T: Bar1<'^0.0, '^0.1>
628 // 1) We must shift all bound vars in predicate by the length
629 // of trait ref's bound vars. So, we would end up with predicate like
630 // Self: Bar1<'a, '^0.1>
631 // 2) We can then apply the trait substs to this, ending up with
632 // T: Bar1<'^0.0, '^0.1>
633 // 3) Finally, to create the final bound vars, we concatenate the bound
634 // vars of the trait ref with those of the predicate:
636 let bound_pred = self.kind();
637 let pred_bound_vars = bound_pred.bound_vars();
638 let trait_bound_vars = trait_ref.bound_vars();
639 // 1) Self: Bar1<'a, '^0.0> -> Self: Bar1<'a, '^0.1>
641 tcx.shift_bound_var_indices(trait_bound_vars.len(), bound_pred.skip_binder());
642 // 2) Self: Bar1<'a, '^0.1> -> T: Bar1<'^0.0, '^0.1>
643 let new = shifted_pred.subst(tcx, trait_ref.skip_binder().substs);
644 // 3) ['x] + ['b] -> ['x, 'b]
646 tcx.mk_bound_variable_kinds(trait_bound_vars.iter().chain(pred_bound_vars));
647 tcx.reuse_or_mk_predicate(self, ty::Binder::bind_with_vars(new, bound_vars))
651 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
652 #[derive(HashStable, TypeFoldable)]
653 pub struct TraitPredicate<'tcx> {
654 pub trait_ref: TraitRef<'tcx>,
656 pub constness: BoundConstness,
659 pub type PolyTraitPredicate<'tcx> = ty::Binder<'tcx, TraitPredicate<'tcx>>;
661 impl<'tcx> TraitPredicate<'tcx> {
662 pub fn def_id(self) -> DefId {
663 self.trait_ref.def_id
666 pub fn self_ty(self) -> Ty<'tcx> {
667 self.trait_ref.self_ty()
671 impl<'tcx> PolyTraitPredicate<'tcx> {
672 pub fn def_id(self) -> DefId {
673 // Ok to skip binder since trait `DefId` does not care about regions.
674 self.skip_binder().def_id()
677 pub fn self_ty(self) -> ty::Binder<'tcx, Ty<'tcx>> {
678 self.map_bound(|trait_ref| trait_ref.self_ty())
682 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
683 #[derive(HashStable, TypeFoldable)]
684 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
685 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
686 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
687 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<'tcx, RegionOutlivesPredicate<'tcx>>;
688 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<'tcx, TypeOutlivesPredicate<'tcx>>;
690 /// Encodes that `a` must be a subtype of `b`. The `a_is_expected` flag indicates
691 /// whether the `a` type is the type that we should label as "expected" when
692 /// presenting user diagnostics.
693 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
694 #[derive(HashStable, TypeFoldable)]
695 pub struct SubtypePredicate<'tcx> {
696 pub a_is_expected: bool,
700 pub type PolySubtypePredicate<'tcx> = ty::Binder<'tcx, SubtypePredicate<'tcx>>;
702 /// Encodes that we have to coerce *from* the `a` type to the `b` type.
703 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
704 #[derive(HashStable, TypeFoldable)]
705 pub struct CoercePredicate<'tcx> {
709 pub type PolyCoercePredicate<'tcx> = ty::Binder<'tcx, CoercePredicate<'tcx>>;
711 /// This kind of predicate has no *direct* correspondent in the
712 /// syntax, but it roughly corresponds to the syntactic forms:
714 /// 1. `T: TraitRef<..., Item = Type>`
715 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
717 /// In particular, form #1 is "desugared" to the combination of a
718 /// normal trait predicate (`T: TraitRef<...>`) and one of these
719 /// predicates. Form #2 is a broader form in that it also permits
720 /// equality between arbitrary types. Processing an instance of
721 /// Form #2 eventually yields one of these `ProjectionPredicate`
722 /// instances to normalize the LHS.
723 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
724 #[derive(HashStable, TypeFoldable)]
725 pub struct ProjectionPredicate<'tcx> {
726 pub projection_ty: ProjectionTy<'tcx>,
730 pub type PolyProjectionPredicate<'tcx> = Binder<'tcx, ProjectionPredicate<'tcx>>;
732 impl<'tcx> PolyProjectionPredicate<'tcx> {
733 /// Returns the `DefId` of the trait of the associated item being projected.
735 pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
736 self.skip_binder().projection_ty.trait_def_id(tcx)
739 /// Get the [PolyTraitRef] required for this projection to be well formed.
740 /// Note that for generic associated types the predicates of the associated
741 /// type also need to be checked.
743 pub fn required_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
744 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
745 // `self.0.trait_ref` is permitted to have escaping regions.
746 // This is because here `self` has a `Binder` and so does our
747 // return value, so we are preserving the number of binding
749 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
752 pub fn ty(&self) -> Binder<'tcx, Ty<'tcx>> {
753 self.map_bound(|predicate| predicate.ty)
756 /// The `DefId` of the `TraitItem` for the associated type.
758 /// Note that this is not the `DefId` of the `TraitRef` containing this
759 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
760 pub fn projection_def_id(&self) -> DefId {
761 // Ok to skip binder since trait `DefId` does not care about regions.
762 self.skip_binder().projection_ty.item_def_id
766 pub trait ToPolyTraitRef<'tcx> {
767 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
770 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
771 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
772 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
776 pub trait ToPredicate<'tcx> {
777 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx>;
780 impl ToPredicate<'tcx> for Binder<'tcx, PredicateKind<'tcx>> {
782 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
783 tcx.mk_predicate(self)
787 impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<PolyTraitRef<'tcx>> {
788 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
790 .map_bound(|trait_ref| {
791 PredicateKind::Trait(ty::TraitPredicate { trait_ref, constness: self.constness })
797 impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
798 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
799 self.map_bound(PredicateKind::Trait).to_predicate(tcx)
803 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
804 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
805 self.map_bound(PredicateKind::RegionOutlives).to_predicate(tcx)
809 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
810 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
811 self.map_bound(PredicateKind::TypeOutlives).to_predicate(tcx)
815 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
816 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
817 self.map_bound(PredicateKind::Projection).to_predicate(tcx)
821 impl<'tcx> Predicate<'tcx> {
822 pub fn to_opt_poly_trait_ref(self) -> Option<ConstnessAnd<PolyTraitRef<'tcx>>> {
823 let predicate = self.kind();
824 match predicate.skip_binder() {
825 PredicateKind::Trait(t) => {
826 Some(ConstnessAnd { constness: t.constness, value: predicate.rebind(t.trait_ref) })
828 PredicateKind::Projection(..)
829 | PredicateKind::Subtype(..)
830 | PredicateKind::Coerce(..)
831 | PredicateKind::RegionOutlives(..)
832 | PredicateKind::WellFormed(..)
833 | PredicateKind::ObjectSafe(..)
834 | PredicateKind::ClosureKind(..)
835 | PredicateKind::TypeOutlives(..)
836 | PredicateKind::ConstEvaluatable(..)
837 | PredicateKind::ConstEquate(..)
838 | PredicateKind::TypeWellFormedFromEnv(..) => None,
842 pub fn to_opt_type_outlives(self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
843 let predicate = self.kind();
844 match predicate.skip_binder() {
845 PredicateKind::TypeOutlives(data) => Some(predicate.rebind(data)),
846 PredicateKind::Trait(..)
847 | PredicateKind::Projection(..)
848 | PredicateKind::Subtype(..)
849 | PredicateKind::Coerce(..)
850 | PredicateKind::RegionOutlives(..)
851 | PredicateKind::WellFormed(..)
852 | PredicateKind::ObjectSafe(..)
853 | PredicateKind::ClosureKind(..)
854 | PredicateKind::ConstEvaluatable(..)
855 | PredicateKind::ConstEquate(..)
856 | PredicateKind::TypeWellFormedFromEnv(..) => None,
861 /// Represents the bounds declared on a particular set of type
862 /// parameters. Should eventually be generalized into a flag list of
863 /// where-clauses. You can obtain an `InstantiatedPredicates` list from a
864 /// `GenericPredicates` by using the `instantiate` method. Note that this method
865 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
866 /// the `GenericPredicates` are expressed in terms of the bound type
867 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
868 /// represented a set of bounds for some particular instantiation,
869 /// meaning that the generic parameters have been substituted with
874 /// struct Foo<T, U: Bar<T>> { ... }
876 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
877 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
878 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
879 /// [usize:Bar<isize>]]`.
880 #[derive(Clone, Debug, TypeFoldable)]
881 pub struct InstantiatedPredicates<'tcx> {
882 pub predicates: Vec<Predicate<'tcx>>,
883 pub spans: Vec<Span>,
886 impl<'tcx> InstantiatedPredicates<'tcx> {
887 pub fn empty() -> InstantiatedPredicates<'tcx> {
888 InstantiatedPredicates { predicates: vec![], spans: vec![] }
891 pub fn is_empty(&self) -> bool {
892 self.predicates.is_empty()
896 #[derive(Copy, Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable, TypeFoldable)]
897 pub struct OpaqueTypeKey<'tcx> {
899 pub substs: SubstsRef<'tcx>,
902 rustc_index::newtype_index! {
903 /// "Universes" are used during type- and trait-checking in the
904 /// presence of `for<..>` binders to control what sets of names are
905 /// visible. Universes are arranged into a tree: the root universe
906 /// contains names that are always visible. Each child then adds a new
907 /// set of names that are visible, in addition to those of its parent.
908 /// We say that the child universe "extends" the parent universe with
911 /// To make this more concrete, consider this program:
915 /// fn bar<T>(x: T) {
916 /// let y: for<'a> fn(&'a u8, Foo) = ...;
920 /// The struct name `Foo` is in the root universe U0. But the type
921 /// parameter `T`, introduced on `bar`, is in an extended universe U1
922 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
923 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
924 /// region `'a` is in a universe U2 that extends U1, because we can
925 /// name it inside the fn type but not outside.
927 /// Universes are used to do type- and trait-checking around these
928 /// "forall" binders (also called **universal quantification**). The
929 /// idea is that when, in the body of `bar`, we refer to `T` as a
930 /// type, we aren't referring to any type in particular, but rather a
931 /// kind of "fresh" type that is distinct from all other types we have
932 /// actually declared. This is called a **placeholder** type, and we
933 /// use universes to talk about this. In other words, a type name in
934 /// universe 0 always corresponds to some "ground" type that the user
935 /// declared, but a type name in a non-zero universe is a placeholder
936 /// type -- an idealized representative of "types in general" that we
937 /// use for checking generic functions.
938 pub struct UniverseIndex {
940 DEBUG_FORMAT = "U{}",
945 pub const ROOT: UniverseIndex = UniverseIndex::from_u32(0);
947 /// Returns the "next" universe index in order -- this new index
948 /// is considered to extend all previous universes. This
949 /// corresponds to entering a `forall` quantifier. So, for
950 /// example, suppose we have this type in universe `U`:
953 /// for<'a> fn(&'a u32)
956 /// Once we "enter" into this `for<'a>` quantifier, we are in a
957 /// new universe that extends `U` -- in this new universe, we can
958 /// name the region `'a`, but that region was not nameable from
959 /// `U` because it was not in scope there.
960 pub fn next_universe(self) -> UniverseIndex {
961 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
964 /// Returns `true` if `self` can name a name from `other` -- in other words,
965 /// if the set of names in `self` is a superset of those in
966 /// `other` (`self >= other`).
967 pub fn can_name(self, other: UniverseIndex) -> bool {
968 self.private >= other.private
971 /// Returns `true` if `self` cannot name some names from `other` -- in other
972 /// words, if the set of names in `self` is a strict subset of
973 /// those in `other` (`self < other`).
974 pub fn cannot_name(self, other: UniverseIndex) -> bool {
975 self.private < other.private
979 /// The "placeholder index" fully defines a placeholder region, type, or const. Placeholders are
980 /// identified by both a universe, as well as a name residing within that universe. Distinct bound
981 /// regions/types/consts within the same universe simply have an unknown relationship to one
983 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, PartialOrd, Ord)]
984 pub struct Placeholder<T> {
985 pub universe: UniverseIndex,
989 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
991 T: HashStable<StableHashingContext<'a>>,
993 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
994 self.universe.hash_stable(hcx, hasher);
995 self.name.hash_stable(hcx, hasher);
999 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
1001 pub type PlaceholderType = Placeholder<BoundVar>;
1003 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1004 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]
1005 pub struct BoundConst<'tcx> {
1010 pub type PlaceholderConst<'tcx> = Placeholder<BoundConst<'tcx>>;
1012 /// A `DefId` which, in case it is a const argument, is potentially bundled with
1013 /// the `DefId` of the generic parameter it instantiates.
1015 /// This is used to avoid calls to `type_of` for const arguments during typeck
1016 /// which cause cycle errors.
1021 /// fn foo<const N: usize>(&self) -> [u8; N] { [0; N] }
1022 /// // ^ const parameter
1026 /// fn foo<const M: u8>(&self) -> usize { 42 }
1027 /// // ^ const parameter
1032 /// let _b = a.foo::<{ 3 + 7 }>();
1033 /// // ^^^^^^^^^ const argument
1037 /// Let's look at the call `a.foo::<{ 3 + 7 }>()` here. We do not know
1038 /// which `foo` is used until we know the type of `a`.
1040 /// We only know the type of `a` once we are inside of `typeck(main)`.
1041 /// We also end up normalizing the type of `_b` during `typeck(main)` which
1042 /// requires us to evaluate the const argument.
1044 /// To evaluate that const argument we need to know its type,
1045 /// which we would get using `type_of(const_arg)`. This requires us to
1046 /// resolve `foo` as it can be either `usize` or `u8` in this example.
1047 /// However, resolving `foo` once again requires `typeck(main)` to get the type of `a`,
1048 /// which results in a cycle.
1050 /// In short we must not call `type_of(const_arg)` during `typeck(main)`.
1052 /// When first creating the `ty::Const` of the const argument inside of `typeck` we have
1053 /// already resolved `foo` so we know which const parameter this argument instantiates.
1054 /// This means that we also know the expected result of `type_of(const_arg)` even if we
1055 /// aren't allowed to call that query: it is equal to `type_of(const_param)` which is
1056 /// trivial to compute.
1058 /// If we now want to use that constant in a place which potentionally needs its type
1059 /// we also pass the type of its `const_param`. This is the point of `WithOptConstParam`,
1060 /// except that instead of a `Ty` we bundle the `DefId` of the const parameter.
1061 /// Meaning that we need to use `type_of(const_param_did)` if `const_param_did` is `Some`
1062 /// to get the type of `did`.
1063 #[derive(Copy, Clone, Debug, TypeFoldable, Lift, TyEncodable, TyDecodable)]
1064 #[derive(PartialEq, Eq, PartialOrd, Ord)]
1065 #[derive(Hash, HashStable)]
1066 pub struct WithOptConstParam<T> {
1068 /// The `DefId` of the corresponding generic parameter in case `did` is
1069 /// a const argument.
1071 /// Note that even if `did` is a const argument, this may still be `None`.
1072 /// All queries taking `WithOptConstParam` start by calling `tcx.opt_const_param_of(def.did)`
1073 /// to potentially update `param_did` in the case it is `None`.
1074 pub const_param_did: Option<DefId>,
1077 impl<T> WithOptConstParam<T> {
1078 /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`.
1080 pub fn unknown(did: T) -> WithOptConstParam<T> {
1081 WithOptConstParam { did, const_param_did: None }
1085 impl WithOptConstParam<LocalDefId> {
1086 /// Returns `Some((did, param_did))` if `def_id` is a const argument,
1087 /// `None` otherwise.
1089 pub fn try_lookup(did: LocalDefId, tcx: TyCtxt<'_>) -> Option<(LocalDefId, DefId)> {
1090 tcx.opt_const_param_of(did).map(|param_did| (did, param_did))
1093 /// In case `self` is unknown but `self.did` is a const argument, this returns
1094 /// a `WithOptConstParam` with the correct `const_param_did`.
1096 pub fn try_upgrade(self, tcx: TyCtxt<'_>) -> Option<WithOptConstParam<LocalDefId>> {
1097 if self.const_param_did.is_none() {
1098 if let const_param_did @ Some(_) = tcx.opt_const_param_of(self.did) {
1099 return Some(WithOptConstParam { did: self.did, const_param_did });
1106 pub fn to_global(self) -> WithOptConstParam<DefId> {
1107 WithOptConstParam { did: self.did.to_def_id(), const_param_did: self.const_param_did }
1110 pub fn def_id_for_type_of(self) -> DefId {
1111 if let Some(did) = self.const_param_did { did } else { self.did.to_def_id() }
1115 impl WithOptConstParam<DefId> {
1116 pub fn as_local(self) -> Option<WithOptConstParam<LocalDefId>> {
1119 .map(|did| WithOptConstParam { did, const_param_did: self.const_param_did })
1122 pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)> {
1123 if let Some(param_did) = self.const_param_did {
1124 if let Some(did) = self.did.as_local() {
1125 return Some((did, param_did));
1132 pub fn is_local(self) -> bool {
1136 pub fn def_id_for_type_of(self) -> DefId {
1137 self.const_param_did.unwrap_or(self.did)
1141 /// When type checking, we use the `ParamEnv` to track
1142 /// details about the set of where-clauses that are in scope at this
1143 /// particular point.
1144 #[derive(Copy, Clone, Hash, PartialEq, Eq)]
1145 pub struct ParamEnv<'tcx> {
1146 /// This packs both caller bounds and the reveal enum into one pointer.
1148 /// Caller bounds are `Obligation`s that the caller must satisfy. This is
1149 /// basically the set of bounds on the in-scope type parameters, translated
1150 /// into `Obligation`s, and elaborated and normalized.
1152 /// Use the `caller_bounds()` method to access.
1154 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1155 /// want `Reveal::All`.
1157 /// Note: This is packed, use the reveal() method to access it.
1158 packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, traits::Reveal, true>,
1161 unsafe impl rustc_data_structures::tagged_ptr::Tag for traits::Reveal {
1162 const BITS: usize = 1;
1164 fn into_usize(self) -> usize {
1166 traits::Reveal::UserFacing => 0,
1167 traits::Reveal::All => 1,
1171 unsafe fn from_usize(ptr: usize) -> Self {
1173 0 => traits::Reveal::UserFacing,
1174 1 => traits::Reveal::All,
1175 _ => std::hint::unreachable_unchecked(),
1180 impl<'tcx> fmt::Debug for ParamEnv<'tcx> {
1181 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1182 f.debug_struct("ParamEnv")
1183 .field("caller_bounds", &self.caller_bounds())
1184 .field("reveal", &self.reveal())
1189 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx> {
1190 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1191 self.caller_bounds().hash_stable(hcx, hasher);
1192 self.reveal().hash_stable(hcx, hasher);
1196 impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
1197 fn super_fold_with<F: ty::fold::TypeFolder<'tcx>>(self, folder: &mut F) -> Self {
1198 ParamEnv::new(self.caller_bounds().fold_with(folder), self.reveal().fold_with(folder))
1201 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
1202 self.caller_bounds().visit_with(visitor)?;
1203 self.reveal().visit_with(visitor)
1207 impl<'tcx> ParamEnv<'tcx> {
1208 /// Construct a trait environment suitable for contexts where
1209 /// there are no where-clauses in scope. Hidden types (like `impl
1210 /// Trait`) are left hidden, so this is suitable for ordinary
1213 pub fn empty() -> Self {
1214 Self::new(List::empty(), Reveal::UserFacing)
1218 pub fn caller_bounds(self) -> &'tcx List<Predicate<'tcx>> {
1219 self.packed.pointer()
1223 pub fn reveal(self) -> traits::Reveal {
1227 /// Construct a trait environment with no where-clauses in scope
1228 /// where the values of all `impl Trait` and other hidden types
1229 /// are revealed. This is suitable for monomorphized, post-typeck
1230 /// environments like codegen or doing optimizations.
1232 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1233 /// or invoke `param_env.with_reveal_all()`.
1235 pub fn reveal_all() -> Self {
1236 Self::new(List::empty(), Reveal::All)
1239 /// Construct a trait environment with the given set of predicates.
1241 pub fn new(caller_bounds: &'tcx List<Predicate<'tcx>>, reveal: Reveal) -> Self {
1242 ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, reveal) }
1245 pub fn with_user_facing(mut self) -> Self {
1246 self.packed.set_tag(Reveal::UserFacing);
1250 /// Returns a new parameter environment with the same clauses, but
1251 /// which "reveals" the true results of projections in all cases
1252 /// (even for associated types that are specializable). This is
1253 /// the desired behavior during codegen and certain other special
1254 /// contexts; normally though we want to use `Reveal::UserFacing`,
1255 /// which is the default.
1256 /// All opaque types in the caller_bounds of the `ParamEnv`
1257 /// will be normalized to their underlying types.
1258 /// See PR #65989 and issue #65918 for more details
1259 pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self {
1260 if self.packed.tag() == traits::Reveal::All {
1264 ParamEnv::new(tcx.normalize_opaque_types(self.caller_bounds()), Reveal::All)
1267 /// Returns this same environment but with no caller bounds.
1269 pub fn without_caller_bounds(self) -> Self {
1270 Self::new(List::empty(), self.reveal())
1273 /// Creates a suitable environment in which to perform trait
1274 /// queries on the given value. When type-checking, this is simply
1275 /// the pair of the environment plus value. But when reveal is set to
1276 /// All, then if `value` does not reference any type parameters, we will
1277 /// pair it with the empty environment. This improves caching and is generally
1280 /// N.B., we preserve the environment when type-checking because it
1281 /// is possible for the user to have wacky where-clauses like
1282 /// `where Box<u32>: Copy`, which are clearly never
1283 /// satisfiable. We generally want to behave as if they were true,
1284 /// although the surrounding function is never reachable.
1285 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1286 match self.reveal() {
1287 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1290 if value.is_known_global() {
1291 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1293 ParamEnvAnd { param_env: self, value }
1300 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1301 pub struct ConstnessAnd<T> {
1302 pub constness: BoundConstness,
1306 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
1307 // the constness of trait bounds is being propagated correctly.
1308 pub trait WithConstness: Sized {
1310 fn with_constness(self, constness: BoundConstness) -> ConstnessAnd<Self> {
1311 ConstnessAnd { constness, value: self }
1315 fn with_const_if_const(self) -> ConstnessAnd<Self> {
1316 self.with_constness(BoundConstness::ConstIfConst)
1320 fn without_const(self) -> ConstnessAnd<Self> {
1321 self.with_constness(BoundConstness::NotConst)
1325 impl<T> WithConstness for T {}
1327 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1328 pub struct ParamEnvAnd<'tcx, T> {
1329 pub param_env: ParamEnv<'tcx>,
1333 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1334 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1335 (self.param_env, self.value)
1339 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1341 T: HashStable<StableHashingContext<'a>>,
1343 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1344 let ParamEnvAnd { ref param_env, ref value } = *self;
1346 param_env.hash_stable(hcx, hasher);
1347 value.hash_stable(hcx, hasher);
1351 #[derive(Copy, Clone, Debug, HashStable)]
1352 pub struct Destructor {
1353 /// The `DefId` of the destructor method
1355 /// The constness of the destructor method
1356 pub constness: hir::Constness,
1360 #[derive(HashStable)]
1361 pub struct VariantFlags: u32 {
1362 const NO_VARIANT_FLAGS = 0;
1363 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1364 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1365 /// Indicates whether this variant was obtained as part of recovering from
1366 /// a syntactic error. May be incomplete or bogus.
1367 const IS_RECOVERED = 1 << 1;
1371 /// Definition of a variant -- a struct's fields or an enum variant.
1372 #[derive(Debug, HashStable)]
1373 pub struct VariantDef {
1374 /// `DefId` that identifies the variant itself.
1375 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1377 /// `DefId` that identifies the variant's constructor.
1378 /// If this variant is a struct variant, then this is `None`.
1379 pub ctor_def_id: Option<DefId>,
1380 /// Variant or struct name.
1381 #[stable_hasher(project(name))]
1383 /// Discriminant of this variant.
1384 pub discr: VariantDiscr,
1385 /// Fields of this variant.
1386 pub fields: Vec<FieldDef>,
1387 /// Type of constructor of variant.
1388 pub ctor_kind: CtorKind,
1389 /// Flags of the variant (e.g. is field list non-exhaustive)?
1390 flags: VariantFlags,
1394 /// Creates a new `VariantDef`.
1396 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1397 /// represents an enum variant).
1399 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1400 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1402 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1403 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1404 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1405 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1406 /// built-in trait), and we do not want to load attributes twice.
1408 /// If someone speeds up attribute loading to not be a performance concern, they can
1409 /// remove this hack and use the constructor `DefId` everywhere.
1412 variant_did: Option<DefId>,
1413 ctor_def_id: Option<DefId>,
1414 discr: VariantDiscr,
1415 fields: Vec<FieldDef>,
1416 ctor_kind: CtorKind,
1420 is_field_list_non_exhaustive: bool,
1423 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1424 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1425 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1428 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1429 if is_field_list_non_exhaustive {
1430 flags |= VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1434 flags |= VariantFlags::IS_RECOVERED;
1438 def_id: variant_did.unwrap_or(parent_did),
1448 /// Is this field list non-exhaustive?
1450 pub fn is_field_list_non_exhaustive(&self) -> bool {
1451 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1454 /// Was this variant obtained as part of recovering from a syntactic error?
1456 pub fn is_recovered(&self) -> bool {
1457 self.flags.intersects(VariantFlags::IS_RECOVERED)
1461 #[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
1462 pub enum VariantDiscr {
1463 /// Explicit value for this variant, i.e., `X = 123`.
1464 /// The `DefId` corresponds to the embedded constant.
1467 /// The previous variant's discriminant plus one.
1468 /// For efficiency reasons, the distance from the
1469 /// last `Explicit` discriminant is being stored,
1470 /// or `0` for the first variant, if it has none.
1474 #[derive(Debug, HashStable)]
1475 pub struct FieldDef {
1477 #[stable_hasher(project(name))]
1479 pub vis: Visibility,
1483 #[derive(TyEncodable, TyDecodable, Default, HashStable)]
1484 pub struct ReprFlags: u8 {
1485 const IS_C = 1 << 0;
1486 const IS_SIMD = 1 << 1;
1487 const IS_TRANSPARENT = 1 << 2;
1488 // Internal only for now. If true, don't reorder fields.
1489 const IS_LINEAR = 1 << 3;
1490 // If true, don't expose any niche to type's context.
1491 const HIDE_NICHE = 1 << 4;
1492 // If true, the type's layout can be randomized using
1493 // the seed stored in `ReprOptions.layout_seed`
1494 const RANDOMIZE_LAYOUT = 1 << 5;
1495 // Any of these flags being set prevent field reordering optimisation.
1496 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1497 ReprFlags::IS_SIMD.bits |
1498 ReprFlags::IS_LINEAR.bits;
1502 /// Represents the repr options provided by the user,
1503 #[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Default, HashStable)]
1504 pub struct ReprOptions {
1505 pub int: Option<attr::IntType>,
1506 pub align: Option<Align>,
1507 pub pack: Option<Align>,
1508 pub flags: ReprFlags,
1509 /// The seed to be used for randomizing a type's layout
1511 /// Note: This could technically be a `[u8; 16]` (a `u128`) which would
1512 /// be the "most accurate" hash as it'd encompass the item and crate
1513 /// hash without loss, but it does pay the price of being larger.
1514 /// Everything's a tradeoff, a `u64` seed should be sufficient for our
1515 /// purposes (primarily `-Z randomize-layout`)
1516 pub field_shuffle_seed: u64,
1520 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
1521 let mut flags = ReprFlags::empty();
1522 let mut size = None;
1523 let mut max_align: Option<Align> = None;
1524 let mut min_pack: Option<Align> = None;
1526 // Generate a deterministically-derived seed from the item's path hash
1527 // to allow for cross-crate compilation to actually work
1528 let field_shuffle_seed = tcx.def_path_hash(did).0.to_smaller_hash();
1530 for attr in tcx.get_attrs(did).iter() {
1531 for r in attr::find_repr_attrs(&tcx.sess, attr) {
1532 flags.insert(match r {
1533 attr::ReprC => ReprFlags::IS_C,
1534 attr::ReprPacked(pack) => {
1535 let pack = Align::from_bytes(pack as u64).unwrap();
1536 min_pack = Some(if let Some(min_pack) = min_pack {
1543 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1544 attr::ReprNoNiche => ReprFlags::HIDE_NICHE,
1545 attr::ReprSimd => ReprFlags::IS_SIMD,
1546 attr::ReprInt(i) => {
1550 attr::ReprAlign(align) => {
1551 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
1558 // If `-Z randomize-layout` was enabled for the type definition then we can
1559 // consider performing layout randomization
1560 if tcx.sess.opts.debugging_opts.randomize_layout {
1561 flags.insert(ReprFlags::RANDOMIZE_LAYOUT);
1564 // This is here instead of layout because the choice must make it into metadata.
1565 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
1566 flags.insert(ReprFlags::IS_LINEAR);
1569 Self { int: size, align: max_align, pack: min_pack, flags, field_shuffle_seed }
1573 pub fn simd(&self) -> bool {
1574 self.flags.contains(ReprFlags::IS_SIMD)
1578 pub fn c(&self) -> bool {
1579 self.flags.contains(ReprFlags::IS_C)
1583 pub fn packed(&self) -> bool {
1588 pub fn transparent(&self) -> bool {
1589 self.flags.contains(ReprFlags::IS_TRANSPARENT)
1593 pub fn linear(&self) -> bool {
1594 self.flags.contains(ReprFlags::IS_LINEAR)
1598 pub fn hide_niche(&self) -> bool {
1599 self.flags.contains(ReprFlags::HIDE_NICHE)
1602 /// Returns the discriminant type, given these `repr` options.
1603 /// This must only be called on enums!
1604 pub fn discr_type(&self) -> attr::IntType {
1605 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1608 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
1609 /// layout" optimizations, such as representing `Foo<&T>` as a
1611 pub fn inhibit_enum_layout_opt(&self) -> bool {
1612 self.c() || self.int.is_some()
1615 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
1616 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
1617 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1618 if let Some(pack) = self.pack {
1619 if pack.bytes() == 1 {
1624 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
1627 /// Returns `true` if this type is valid for reordering and `-Z randomize-layout`
1628 /// was enabled for its declaration crate
1629 pub fn can_randomize_type_layout(&self) -> bool {
1630 !self.inhibit_struct_field_reordering_opt()
1631 && self.flags.contains(ReprFlags::RANDOMIZE_LAYOUT)
1634 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
1635 pub fn inhibit_union_abi_opt(&self) -> bool {
1640 impl<'tcx> FieldDef {
1641 /// Returns the type of this field. The `subst` is typically obtained
1642 /// via the second field of `TyKind::AdtDef`.
1643 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
1644 tcx.type_of(self.did).subst(tcx, subst)
1648 pub type Attributes<'tcx> = &'tcx [ast::Attribute];
1650 #[derive(Debug, PartialEq, Eq)]
1651 pub enum ImplOverlapKind {
1652 /// These impls are always allowed to overlap.
1654 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
1657 /// These impls are allowed to overlap, but that raises
1658 /// an issue #33140 future-compatibility warning.
1660 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
1661 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
1663 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
1664 /// that difference, making what reduces to the following set of impls:
1668 /// impl Trait for dyn Send + Sync {}
1669 /// impl Trait for dyn Sync + Send {}
1672 /// Obviously, once we made these types be identical, that code causes a coherence
1673 /// error and a fairly big headache for us. However, luckily for us, the trait
1674 /// `Trait` used in this case is basically a marker trait, and therefore having
1675 /// overlapping impls for it is sound.
1677 /// To handle this, we basically regard the trait as a marker trait, with an additional
1678 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
1679 /// it has the following restrictions:
1681 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
1683 /// 2. The trait-ref of both impls must be equal.
1684 /// 3. The trait-ref of both impls must be a trait object type consisting only of
1686 /// 4. Neither of the impls can have any where-clauses.
1688 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
1692 impl<'tcx> TyCtxt<'tcx> {
1693 pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> {
1694 self.typeck(self.hir().body_owner_def_id(body))
1697 pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
1698 self.associated_items(id)
1699 .in_definition_order()
1700 .filter(|item| item.kind == AssocKind::Fn && item.defaultness.has_value())
1703 fn item_name_from_hir(self, def_id: DefId) -> Option<Ident> {
1704 self.hir().get_if_local(def_id).and_then(|node| node.ident())
1707 fn item_name_from_def_id(self, def_id: DefId) -> Option<Symbol> {
1708 if def_id.index == CRATE_DEF_INDEX {
1709 Some(self.crate_name(def_id.krate))
1711 let def_key = self.def_key(def_id);
1712 match def_key.disambiguated_data.data {
1713 // The name of a constructor is that of its parent.
1714 rustc_hir::definitions::DefPathData::Ctor => self.item_name_from_def_id(DefId {
1715 krate: def_id.krate,
1716 index: def_key.parent.unwrap(),
1718 _ => def_key.disambiguated_data.data.get_opt_name(),
1723 /// Look up the name of an item across crates. This does not look at HIR.
1725 /// When possible, this function should be used for cross-crate lookups over
1726 /// [`opt_item_name`] to avoid invalidating the incremental cache. If you
1727 /// need to handle items without a name, or HIR items that will not be
1728 /// serialized cross-crate, or if you need the span of the item, use
1729 /// [`opt_item_name`] instead.
1731 /// [`opt_item_name`]: Self::opt_item_name
1732 pub fn item_name(self, id: DefId) -> Symbol {
1733 // Look at cross-crate items first to avoid invalidating the incremental cache
1734 // unless we have to.
1735 self.item_name_from_def_id(id).unwrap_or_else(|| {
1736 bug!("item_name: no name for {:?}", self.def_path(id));
1740 /// Look up the name and span of an item or [`Node`].
1742 /// See [`item_name`][Self::item_name] for more information.
1743 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
1744 // Look at the HIR first so the span will be correct if this is a local item.
1745 self.item_name_from_hir(def_id)
1746 .or_else(|| self.item_name_from_def_id(def_id).map(Ident::with_dummy_span))
1749 pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> {
1750 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
1751 Some(self.associated_item(def_id))
1757 pub fn field_index(self, hir_id: hir::HirId, typeck_results: &TypeckResults<'_>) -> usize {
1758 typeck_results.field_indices().get(hir_id).cloned().expect("no index for a field")
1761 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
1762 variant.fields.iter().position(|field| self.hygienic_eq(ident, field.ident, variant.def_id))
1765 /// Returns `true` if the impls are the same polarity and the trait either
1766 /// has no items or is annotated `#[marker]` and prevents item overrides.
1767 pub fn impls_are_allowed_to_overlap(
1771 ) -> Option<ImplOverlapKind> {
1772 // If either trait impl references an error, they're allowed to overlap,
1773 // as one of them essentially doesn't exist.
1774 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
1775 || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
1777 return Some(ImplOverlapKind::Permitted { marker: false });
1780 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
1781 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
1782 // `#[rustc_reservation_impl]` impls don't overlap with anything
1784 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
1787 return Some(ImplOverlapKind::Permitted { marker: false });
1789 (ImplPolarity::Positive, ImplPolarity::Negative)
1790 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
1791 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
1793 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
1798 (ImplPolarity::Positive, ImplPolarity::Positive)
1799 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
1802 let is_marker_overlap = {
1803 let is_marker_impl = |def_id: DefId| -> bool {
1804 let trait_ref = self.impl_trait_ref(def_id);
1805 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
1807 is_marker_impl(def_id1) && is_marker_impl(def_id2)
1810 if is_marker_overlap {
1812 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
1815 Some(ImplOverlapKind::Permitted { marker: true })
1817 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
1818 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
1819 if self_ty1 == self_ty2 {
1821 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
1824 return Some(ImplOverlapKind::Issue33140);
1827 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
1828 def_id1, def_id2, self_ty1, self_ty2
1834 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
1839 /// Returns `ty::VariantDef` if `res` refers to a struct,
1840 /// or variant or their constructors, panics otherwise.
1841 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
1843 Res::Def(DefKind::Variant, did) => {
1844 let enum_did = self.parent(did).unwrap();
1845 self.adt_def(enum_did).variant_with_id(did)
1847 Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(),
1848 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
1849 let variant_did = self.parent(variant_ctor_did).unwrap();
1850 let enum_did = self.parent(variant_did).unwrap();
1851 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
1853 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
1854 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
1855 self.adt_def(struct_did).non_enum_variant()
1857 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
1861 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
1862 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
1864 ty::InstanceDef::Item(def) => match self.def_kind(def.did) {
1867 | DefKind::AssocConst
1869 | DefKind::AnonConst => self.mir_for_ctfe_opt_const_arg(def),
1870 // If the caller wants `mir_for_ctfe` of a function they should not be using
1871 // `instance_mir`, so we'll assume const fn also wants the optimized version.
1873 assert_eq!(def.const_param_did, None);
1874 self.optimized_mir(def.did)
1877 ty::InstanceDef::VtableShim(..)
1878 | ty::InstanceDef::ReifyShim(..)
1879 | ty::InstanceDef::Intrinsic(..)
1880 | ty::InstanceDef::FnPtrShim(..)
1881 | ty::InstanceDef::Virtual(..)
1882 | ty::InstanceDef::ClosureOnceShim { .. }
1883 | ty::InstanceDef::DropGlue(..)
1884 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance),
1888 /// Gets the attributes of a definition.
1889 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
1890 if let Some(did) = did.as_local() {
1891 self.hir().attrs(self.hir().local_def_id_to_hir_id(did))
1893 self.item_attrs(did)
1897 /// Determines whether an item is annotated with an attribute.
1898 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
1899 self.sess.contains_name(&self.get_attrs(did), attr)
1902 /// Returns `true` if this is an `auto trait`.
1903 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
1904 self.trait_def(trait_def_id).has_auto_impl
1907 /// Returns layout of a generator. Layout might be unavailable if the
1908 /// generator is tainted by errors.
1909 pub fn generator_layout(self, def_id: DefId) -> Option<&'tcx GeneratorLayout<'tcx>> {
1910 self.optimized_mir(def_id).generator_layout()
1913 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
1914 /// If it implements no trait, returns `None`.
1915 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
1916 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
1919 /// If the given defid describes a method belonging to an impl, returns the
1920 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
1921 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
1922 self.opt_associated_item(def_id).and_then(|trait_item| match trait_item.container {
1923 TraitContainer(_) => None,
1924 ImplContainer(def_id) => Some(def_id),
1928 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
1929 /// with the name of the crate containing the impl.
1930 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
1931 if let Some(impl_did) = impl_did.as_local() {
1932 let hir_id = self.hir().local_def_id_to_hir_id(impl_did);
1933 Ok(self.hir().span(hir_id))
1935 Err(self.crate_name(impl_did.krate))
1939 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
1940 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
1941 /// definition's parent/scope to perform comparison.
1942 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
1943 // We could use `Ident::eq` here, but we deliberately don't. The name
1944 // comparison fails frequently, and we want to avoid the expensive
1945 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
1946 use_name.name == def_name.name
1950 .hygienic_eq(def_name.span.ctxt(), self.expn_that_defined(def_parent_def_id))
1953 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
1954 ident.span.normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope));
1958 pub fn adjust_ident_and_get_scope(
1963 ) -> (Ident, DefId) {
1966 .normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope))
1967 .and_then(|actual_expansion| actual_expansion.expn_data().parent_module)
1968 .unwrap_or_else(|| self.parent_module(block).to_def_id());
1972 pub fn is_object_safe(self, key: DefId) -> bool {
1973 self.object_safety_violations(key).is_empty()
1977 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
1978 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
1979 if let Some(def_id) = def_id.as_local() {
1980 if let Node::Item(item) = tcx.hir().get(tcx.hir().local_def_id_to_hir_id(def_id)) {
1981 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
1982 return opaque_ty.impl_trait_fn;
1989 pub fn int_ty(ity: ast::IntTy) -> IntTy {
1991 ast::IntTy::Isize => IntTy::Isize,
1992 ast::IntTy::I8 => IntTy::I8,
1993 ast::IntTy::I16 => IntTy::I16,
1994 ast::IntTy::I32 => IntTy::I32,
1995 ast::IntTy::I64 => IntTy::I64,
1996 ast::IntTy::I128 => IntTy::I128,
2000 pub fn uint_ty(uty: ast::UintTy) -> UintTy {
2002 ast::UintTy::Usize => UintTy::Usize,
2003 ast::UintTy::U8 => UintTy::U8,
2004 ast::UintTy::U16 => UintTy::U16,
2005 ast::UintTy::U32 => UintTy::U32,
2006 ast::UintTy::U64 => UintTy::U64,
2007 ast::UintTy::U128 => UintTy::U128,
2011 pub fn float_ty(fty: ast::FloatTy) -> FloatTy {
2013 ast::FloatTy::F32 => FloatTy::F32,
2014 ast::FloatTy::F64 => FloatTy::F64,
2018 pub fn ast_int_ty(ity: IntTy) -> ast::IntTy {
2020 IntTy::Isize => ast::IntTy::Isize,
2021 IntTy::I8 => ast::IntTy::I8,
2022 IntTy::I16 => ast::IntTy::I16,
2023 IntTy::I32 => ast::IntTy::I32,
2024 IntTy::I64 => ast::IntTy::I64,
2025 IntTy::I128 => ast::IntTy::I128,
2029 pub fn ast_uint_ty(uty: UintTy) -> ast::UintTy {
2031 UintTy::Usize => ast::UintTy::Usize,
2032 UintTy::U8 => ast::UintTy::U8,
2033 UintTy::U16 => ast::UintTy::U16,
2034 UintTy::U32 => ast::UintTy::U32,
2035 UintTy::U64 => ast::UintTy::U64,
2036 UintTy::U128 => ast::UintTy::U128,
2040 pub fn provide(providers: &mut ty::query::Providers) {
2041 closure::provide(providers);
2042 context::provide(providers);
2043 erase_regions::provide(providers);
2044 layout::provide(providers);
2045 util::provide(providers);
2046 print::provide(providers);
2047 super::util::bug::provide(providers);
2048 super::middle::provide(providers);
2049 *providers = ty::query::Providers {
2050 trait_impls_of: trait_def::trait_impls_of_provider,
2051 type_uninhabited_from: inhabitedness::type_uninhabited_from,
2052 const_param_default: consts::const_param_default,
2057 /// A map for the local crate mapping each type to a vector of its
2058 /// inherent impls. This is not meant to be used outside of coherence;
2059 /// rather, you should request the vector for a specific type via
2060 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2061 /// (constructing this map requires touching the entire crate).
2062 #[derive(Clone, Debug, Default, HashStable)]
2063 pub struct CrateInherentImpls {
2064 pub inherent_impls: LocalDefIdMap<Vec<DefId>>,
2067 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]
2068 pub struct SymbolName<'tcx> {
2069 /// `&str` gives a consistent ordering, which ensures reproducible builds.
2070 pub name: &'tcx str,
2073 impl<'tcx> SymbolName<'tcx> {
2074 pub fn new(tcx: TyCtxt<'tcx>, name: &str) -> SymbolName<'tcx> {
2076 name: unsafe { str::from_utf8_unchecked(tcx.arena.alloc_slice(name.as_bytes())) },
2081 impl<'tcx> fmt::Display for SymbolName<'tcx> {
2082 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2083 fmt::Display::fmt(&self.name, fmt)
2087 impl<'tcx> fmt::Debug for SymbolName<'tcx> {
2088 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2089 fmt::Display::fmt(&self.name, fmt)
2093 #[derive(Debug, Default, Copy, Clone)]
2094 pub struct FoundRelationships {
2095 /// This is true if we identified that this Ty (`?T`) is found in a `?T: Foo`
2096 /// obligation, where:
2098 /// * `Foo` is not `Sized`
2099 /// * `(): Foo` may be satisfied
2100 pub self_in_trait: bool,
2101 /// This is true if we identified that this Ty (`?T`) is found in a `<_ as
2102 /// _>::AssocType = ?T`