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::mir::{Body, GeneratorLayout};
24 use crate::traits::{self, Reveal};
26 use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
27 use crate::ty::util::Discr;
29 use rustc_attr as attr;
30 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
31 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
32 use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
34 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
35 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalDefIdMap, CRATE_DEF_INDEX};
37 use rustc_macros::HashStable;
38 use rustc_query_system::ich::StableHashingContext;
39 use rustc_session::cstore::CrateStoreDyn;
40 use rustc_span::symbol::{kw, Ident, Symbol};
41 use rustc_span::{sym, Span};
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;
116 mod structural_impls;
122 pub struct ResolverOutputs {
123 pub definitions: rustc_hir::definitions::Definitions,
124 pub cstore: Box<CrateStoreDyn>,
125 pub visibilities: FxHashMap<LocalDefId, Visibility>,
126 pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
127 pub maybe_unused_trait_imports: FxHashSet<LocalDefId>,
128 pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
129 pub export_map: ExportMap,
130 pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
131 /// Extern prelude entries. The value is `true` if the entry was introduced
132 /// via `extern crate` item and not `--extern` option or compiler built-in.
133 pub extern_prelude: FxHashMap<Symbol, bool>,
134 pub main_def: Option<MainDefinition>,
135 pub trait_impls: BTreeMap<DefId, Vec<LocalDefId>>,
136 /// A list of proc macro LocalDefIds, written out in the order in which
137 /// they are declared in the static array generated by proc_macro_harness.
138 pub proc_macros: Vec<LocalDefId>,
139 /// Mapping from ident span to path span for paths that don't exist as written, but that
140 /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
141 pub confused_type_with_std_module: FxHashMap<Span, Span>,
144 #[derive(Clone, Copy, Debug)]
145 pub struct MainDefinition {
146 pub res: Res<ast::NodeId>,
151 impl MainDefinition {
152 pub fn opt_fn_def_id(self) -> Option<DefId> {
153 if let Res::Def(DefKind::Fn, def_id) = self.res { Some(def_id) } else { None }
157 /// The "header" of an impl is everything outside the body: a Self type, a trait
158 /// ref (in the case of a trait impl), and a set of predicates (from the
159 /// bounds / where-clauses).
160 #[derive(Clone, Debug, TypeFoldable)]
161 pub struct ImplHeader<'tcx> {
162 pub impl_def_id: DefId,
163 pub self_ty: Ty<'tcx>,
164 pub trait_ref: Option<TraitRef<'tcx>>,
165 pub predicates: Vec<Predicate<'tcx>>,
168 #[derive(Copy, Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
169 pub enum ImplPolarity {
170 /// `impl Trait for Type`
172 /// `impl !Trait for Type`
174 /// `#[rustc_reservation_impl] impl Trait for Type`
176 /// This is a "stability hack", not a real Rust feature.
177 /// See #64631 for details.
181 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, TyEncodable, TyDecodable, HashStable)]
182 pub enum Visibility {
183 /// Visible everywhere (including in other crates).
185 /// Visible only in the given crate-local module.
187 /// Not visible anywhere in the local crate. This is the visibility of private external items.
191 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
192 pub enum BoundConstness {
195 /// `T: ~const Trait`
197 /// Requires resolving to const only when we are in a const context.
201 impl fmt::Display for BoundConstness {
202 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
204 Self::NotConst => f.write_str("normal"),
205 Self::ConstIfConst => f.write_str("`~const`"),
222 pub struct ClosureSizeProfileData<'tcx> {
223 /// Tuple containing the types of closure captures before the feature `capture_disjoint_fields`
224 pub before_feature_tys: Ty<'tcx>,
225 /// Tuple containing the types of closure captures after the feature `capture_disjoint_fields`
226 pub after_feature_tys: Ty<'tcx>,
229 pub trait DefIdTree: Copy {
230 fn parent(self, id: DefId) -> Option<DefId>;
232 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
233 if descendant.krate != ancestor.krate {
237 while descendant != ancestor {
238 match self.parent(descendant) {
239 Some(parent) => descendant = parent,
240 None => return false,
247 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
248 fn parent(self, id: DefId) -> Option<DefId> {
249 self.def_key(id).parent.map(|index| DefId { index, ..id })
254 pub fn from_hir(visibility: &hir::Visibility<'_>, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
255 match visibility.node {
256 hir::VisibilityKind::Public => Visibility::Public,
257 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
258 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
259 // If there is no resolution, `resolve` will have already reported an error, so
260 // assume that the visibility is public to avoid reporting more privacy errors.
261 Res::Err => Visibility::Public,
262 def => Visibility::Restricted(def.def_id()),
264 hir::VisibilityKind::Inherited => {
265 Visibility::Restricted(tcx.parent_module(id).to_def_id())
270 /// Returns `true` if an item with this visibility is accessible from the given block.
271 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
272 let restriction = match self {
273 // Public items are visible everywhere.
274 Visibility::Public => return true,
275 // Private items from other crates are visible nowhere.
276 Visibility::Invisible => return false,
277 // Restricted items are visible in an arbitrary local module.
278 Visibility::Restricted(other) if other.krate != module.krate => return false,
279 Visibility::Restricted(module) => module,
282 tree.is_descendant_of(module, restriction)
285 /// Returns `true` if this visibility is at least as accessible as the given visibility
286 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
287 let vis_restriction = match vis {
288 Visibility::Public => return self == Visibility::Public,
289 Visibility::Invisible => return true,
290 Visibility::Restricted(module) => module,
293 self.is_accessible_from(vis_restriction, tree)
296 // Returns `true` if this item is visible anywhere in the local crate.
297 pub fn is_visible_locally(self) -> bool {
299 Visibility::Public => true,
300 Visibility::Restricted(def_id) => def_id.is_local(),
301 Visibility::Invisible => false,
306 /// The crate variances map is computed during typeck and contains the
307 /// variance of every item in the local crate. You should not use it
308 /// directly, because to do so will make your pass dependent on the
309 /// HIR of every item in the local crate. Instead, use
310 /// `tcx.variances_of()` to get the variance for a *particular*
312 #[derive(HashStable, Debug)]
313 pub struct CrateVariancesMap<'tcx> {
314 /// For each item with generics, maps to a vector of the variance
315 /// of its generics. If an item has no generics, it will have no
317 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
320 // Contains information needed to resolve types and (in the future) look up
321 // the types of AST nodes.
322 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
323 pub struct CReaderCacheKey {
324 pub cnum: Option<CrateNum>,
328 #[allow(rustc::usage_of_ty_tykind)]
329 pub struct TyS<'tcx> {
330 /// This field shouldn't be used directly and may be removed in the future.
331 /// Use `TyS::kind()` instead.
333 /// This field shouldn't be used directly and may be removed in the future.
334 /// Use `TyS::flags()` instead.
337 /// This is a kind of confusing thing: it stores the smallest
340 /// (a) the binder itself captures nothing but
341 /// (b) all the late-bound things within the type are captured
342 /// by some sub-binder.
344 /// So, for a type without any late-bound things, like `u32`, this
345 /// will be *innermost*, because that is the innermost binder that
346 /// captures nothing. But for a type `&'D u32`, where `'D` is a
347 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
348 /// -- the binder itself does not capture `D`, but `D` is captured
349 /// by an inner binder.
351 /// We call this concept an "exclusive" binder `D` because all
352 /// De Bruijn indices within the type are contained within `0..D`
354 outer_exclusive_binder: ty::DebruijnIndex,
357 impl<'tcx> TyS<'tcx> {
358 /// A constructor used only for internal testing.
359 #[allow(rustc::usage_of_ty_tykind)]
360 pub fn make_for_test(
363 outer_exclusive_binder: ty::DebruijnIndex,
365 TyS { kind, flags, outer_exclusive_binder }
369 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
370 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
371 static_assert_size!(TyS<'_>, 40);
373 impl<'tcx> Ord for TyS<'tcx> {
374 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
375 self.kind().cmp(other.kind())
379 impl<'tcx> PartialOrd for TyS<'tcx> {
380 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
381 Some(self.kind().cmp(other.kind()))
385 impl<'tcx> PartialEq for TyS<'tcx> {
387 fn eq(&self, other: &TyS<'tcx>) -> bool {
391 impl<'tcx> Eq for TyS<'tcx> {}
393 impl<'tcx> Hash for TyS<'tcx> {
394 fn hash<H: Hasher>(&self, s: &mut H) {
395 (self as *const TyS<'_>).hash(s)
399 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
400 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
404 // The other fields just provide fast access to information that is
405 // also contained in `kind`, so no need to hash them.
408 outer_exclusive_binder: _,
411 kind.hash_stable(hcx, hasher);
415 #[rustc_diagnostic_item = "Ty"]
416 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
418 impl ty::EarlyBoundRegion {
419 /// Does this early bound region have a name? Early bound regions normally
420 /// always have names except when using anonymous lifetimes (`'_`).
421 pub fn has_name(&self) -> bool {
422 self.name != kw::UnderscoreLifetime
427 crate struct PredicateInner<'tcx> {
428 kind: Binder<'tcx, PredicateKind<'tcx>>,
430 /// See the comment for the corresponding field of [TyS].
431 outer_exclusive_binder: ty::DebruijnIndex,
434 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
435 static_assert_size!(PredicateInner<'_>, 48);
437 #[derive(Clone, Copy, Lift)]
438 pub struct Predicate<'tcx> {
439 inner: &'tcx PredicateInner<'tcx>,
442 impl<'tcx> PartialEq for Predicate<'tcx> {
443 fn eq(&self, other: &Self) -> bool {
444 // `self.kind` is always interned.
445 ptr::eq(self.inner, other.inner)
449 impl Hash for Predicate<'_> {
450 fn hash<H: Hasher>(&self, s: &mut H) {
451 (self.inner as *const PredicateInner<'_>).hash(s)
455 impl<'tcx> Eq for Predicate<'tcx> {}
457 impl<'tcx> Predicate<'tcx> {
458 /// Gets the inner `Binder<'tcx, PredicateKind<'tcx>>`.
460 pub fn kind(self) -> Binder<'tcx, PredicateKind<'tcx>> {
465 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {
466 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
470 // The other fields just provide fast access to information that is
471 // also contained in `kind`, so no need to hash them.
473 outer_exclusive_binder: _,
476 kind.hash_stable(hcx, hasher);
480 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
481 #[derive(HashStable, TypeFoldable)]
482 pub enum PredicateKind<'tcx> {
483 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
484 /// the `Self` type of the trait reference and `A`, `B`, and `C`
485 /// would be the type parameters.
486 Trait(TraitPredicate<'tcx>),
489 RegionOutlives(RegionOutlivesPredicate<'tcx>),
492 TypeOutlives(TypeOutlivesPredicate<'tcx>),
494 /// `where <T as TraitRef>::Name == X`, approximately.
495 /// See the `ProjectionPredicate` struct for details.
496 Projection(ProjectionPredicate<'tcx>),
498 /// No syntax: `T` well-formed.
499 WellFormed(GenericArg<'tcx>),
501 /// Trait must be object-safe.
504 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
505 /// for some substitutions `...` and `T` being a closure type.
506 /// Satisfied (or refuted) once we know the closure's kind.
507 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
511 /// This obligation is created most often when we have two
512 /// unresolved type variables and hence don't have enough
513 /// information to process the subtyping obligation yet.
514 Subtype(SubtypePredicate<'tcx>),
516 /// `T1` coerced to `T2`
518 /// Like a subtyping obligation, this is created most often
519 /// when we have two unresolved type variables and hence
520 /// don't have enough information to process the coercion
521 /// obligation yet. At the moment, we actually process coercions
522 /// very much like subtyping and don't handle the full coercion
524 Coerce(CoercePredicate<'tcx>),
526 /// Constant initializer must evaluate successfully.
527 ConstEvaluatable(ty::Unevaluated<'tcx, ()>),
529 /// Constants must be equal. The first component is the const that is expected.
530 ConstEquate(&'tcx Const<'tcx>, &'tcx Const<'tcx>),
532 /// Represents a type found in the environment that we can use for implied bounds.
534 /// Only used for Chalk.
535 TypeWellFormedFromEnv(Ty<'tcx>),
538 /// The crate outlives map is computed during typeck and contains the
539 /// outlives of every item in the local crate. You should not use it
540 /// directly, because to do so will make your pass dependent on the
541 /// HIR of every item in the local crate. Instead, use
542 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
544 #[derive(HashStable, Debug)]
545 pub struct CratePredicatesMap<'tcx> {
546 /// For each struct with outlive bounds, maps to a vector of the
547 /// predicate of its outlive bounds. If an item has no outlives
548 /// bounds, it will have no entry.
549 pub predicates: FxHashMap<DefId, &'tcx [(Predicate<'tcx>, Span)]>,
552 impl<'tcx> Predicate<'tcx> {
553 /// Performs a substitution suitable for going from a
554 /// poly-trait-ref to supertraits that must hold if that
555 /// poly-trait-ref holds. This is slightly different from a normal
556 /// substitution in terms of what happens with bound regions. See
557 /// lengthy comment below for details.
558 pub fn subst_supertrait(
561 trait_ref: &ty::PolyTraitRef<'tcx>,
562 ) -> Predicate<'tcx> {
563 // The interaction between HRTB and supertraits is not entirely
564 // obvious. Let me walk you (and myself) through an example.
566 // Let's start with an easy case. Consider two traits:
568 // trait Foo<'a>: Bar<'a,'a> { }
569 // trait Bar<'b,'c> { }
571 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
572 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
573 // knew that `Foo<'x>` (for any 'x) then we also know that
574 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
575 // normal substitution.
577 // In terms of why this is sound, the idea is that whenever there
578 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
579 // holds. So if there is an impl of `T:Foo<'a>` that applies to
580 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
583 // Another example to be careful of is this:
585 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
586 // trait Bar1<'b,'c> { }
588 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
589 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
590 // reason is similar to the previous example: any impl of
591 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
592 // basically we would want to collapse the bound lifetimes from
593 // the input (`trait_ref`) and the supertraits.
595 // To achieve this in practice is fairly straightforward. Let's
596 // consider the more complicated scenario:
598 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
599 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
600 // where both `'x` and `'b` would have a DB index of 1.
601 // The substitution from the input trait-ref is therefore going to be
602 // `'a => 'x` (where `'x` has a DB index of 1).
603 // - The supertrait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
604 // early-bound parameter and `'b' is a late-bound parameter with a
606 // - If we replace `'a` with `'x` from the input, it too will have
607 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
608 // just as we wanted.
610 // There is only one catch. If we just apply the substitution `'a
611 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
612 // adjust the DB index because we substituting into a binder (it
613 // tries to be so smart...) resulting in `for<'x> for<'b>
614 // Bar1<'x,'b>` (we have no syntax for this, so use your
615 // imagination). Basically the 'x will have DB index of 2 and 'b
616 // will have DB index of 1. Not quite what we want. So we apply
617 // the substitution to the *contents* of the trait reference,
618 // rather than the trait reference itself (put another way, the
619 // substitution code expects equal binding levels in the values
620 // from the substitution and the value being substituted into, and
621 // this trick achieves that).
623 // Working through the second example:
624 // trait_ref: for<'x> T: Foo1<'^0.0>; substs: [T, '^0.0]
625 // predicate: for<'b> Self: Bar1<'a, '^0.0>; substs: [Self, 'a, '^0.0]
626 // We want to end up with:
627 // for<'x, 'b> T: Bar1<'^0.0, '^0.1>
629 // 1) We must shift all bound vars in predicate by the length
630 // of trait ref's bound vars. So, we would end up with predicate like
631 // Self: Bar1<'a, '^0.1>
632 // 2) We can then apply the trait substs to this, ending up with
633 // T: Bar1<'^0.0, '^0.1>
634 // 3) Finally, to create the final bound vars, we concatenate the bound
635 // vars of the trait ref with those of the predicate:
637 let bound_pred = self.kind();
638 let pred_bound_vars = bound_pred.bound_vars();
639 let trait_bound_vars = trait_ref.bound_vars();
640 // 1) Self: Bar1<'a, '^0.0> -> Self: Bar1<'a, '^0.1>
642 tcx.shift_bound_var_indices(trait_bound_vars.len(), bound_pred.skip_binder());
643 // 2) Self: Bar1<'a, '^0.1> -> T: Bar1<'^0.0, '^0.1>
644 let new = shifted_pred.subst(tcx, trait_ref.skip_binder().substs);
645 // 3) ['x] + ['b] -> ['x, 'b]
647 tcx.mk_bound_variable_kinds(trait_bound_vars.iter().chain(pred_bound_vars));
648 tcx.reuse_or_mk_predicate(self, ty::Binder::bind_with_vars(new, bound_vars))
652 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
653 #[derive(HashStable, TypeFoldable)]
654 pub struct TraitPredicate<'tcx> {
655 pub trait_ref: TraitRef<'tcx>,
657 pub constness: BoundConstness,
660 pub type PolyTraitPredicate<'tcx> = ty::Binder<'tcx, TraitPredicate<'tcx>>;
662 impl<'tcx> TraitPredicate<'tcx> {
663 pub fn def_id(self) -> DefId {
664 self.trait_ref.def_id
667 pub fn self_ty(self) -> Ty<'tcx> {
668 self.trait_ref.self_ty()
672 impl<'tcx> PolyTraitPredicate<'tcx> {
673 pub fn def_id(self) -> DefId {
674 // Ok to skip binder since trait `DefId` does not care about regions.
675 self.skip_binder().def_id()
678 pub fn self_ty(self) -> ty::Binder<'tcx, Ty<'tcx>> {
679 self.map_bound(|trait_ref| trait_ref.self_ty())
683 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
684 #[derive(HashStable, TypeFoldable)]
685 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
686 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
687 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
688 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<'tcx, RegionOutlivesPredicate<'tcx>>;
689 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<'tcx, TypeOutlivesPredicate<'tcx>>;
691 /// Encodes that `a` must be a subtype of `b`. The `a_is_expected` flag indicates
692 /// whether the `a` type is the type that we should label as "expected" when
693 /// presenting user diagnostics.
694 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
695 #[derive(HashStable, TypeFoldable)]
696 pub struct SubtypePredicate<'tcx> {
697 pub a_is_expected: bool,
701 pub type PolySubtypePredicate<'tcx> = ty::Binder<'tcx, SubtypePredicate<'tcx>>;
703 /// Encodes that we have to coerce *from* the `a` type to the `b` type.
704 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
705 #[derive(HashStable, TypeFoldable)]
706 pub struct CoercePredicate<'tcx> {
710 pub type PolyCoercePredicate<'tcx> = ty::Binder<'tcx, CoercePredicate<'tcx>>;
712 /// This kind of predicate has no *direct* correspondent in the
713 /// syntax, but it roughly corresponds to the syntactic forms:
715 /// 1. `T: TraitRef<..., Item = Type>`
716 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
718 /// In particular, form #1 is "desugared" to the combination of a
719 /// normal trait predicate (`T: TraitRef<...>`) and one of these
720 /// predicates. Form #2 is a broader form in that it also permits
721 /// equality between arbitrary types. Processing an instance of
722 /// Form #2 eventually yields one of these `ProjectionPredicate`
723 /// instances to normalize the LHS.
724 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
725 #[derive(HashStable, TypeFoldable)]
726 pub struct ProjectionPredicate<'tcx> {
727 pub projection_ty: ProjectionTy<'tcx>,
731 pub type PolyProjectionPredicate<'tcx> = Binder<'tcx, ProjectionPredicate<'tcx>>;
733 impl<'tcx> PolyProjectionPredicate<'tcx> {
734 /// Returns the `DefId` of the trait of the associated item being projected.
736 pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
737 self.skip_binder().projection_ty.trait_def_id(tcx)
740 /// Get the [PolyTraitRef] required for this projection to be well formed.
741 /// Note that for generic associated types the predicates of the associated
742 /// type also need to be checked.
744 pub fn required_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
745 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
746 // `self.0.trait_ref` is permitted to have escaping regions.
747 // This is because here `self` has a `Binder` and so does our
748 // return value, so we are preserving the number of binding
750 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
753 pub fn ty(&self) -> Binder<'tcx, Ty<'tcx>> {
754 self.map_bound(|predicate| predicate.ty)
757 /// The `DefId` of the `TraitItem` for the associated type.
759 /// Note that this is not the `DefId` of the `TraitRef` containing this
760 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
761 pub fn projection_def_id(&self) -> DefId {
762 // Ok to skip binder since trait `DefId` does not care about regions.
763 self.skip_binder().projection_ty.item_def_id
767 pub trait ToPolyTraitRef<'tcx> {
768 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
771 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
772 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
773 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
777 pub trait ToPredicate<'tcx> {
778 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx>;
781 impl ToPredicate<'tcx> for Binder<'tcx, PredicateKind<'tcx>> {
783 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
784 tcx.mk_predicate(self)
788 impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<PolyTraitRef<'tcx>> {
789 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
791 .map_bound(|trait_ref| {
792 PredicateKind::Trait(ty::TraitPredicate { trait_ref, constness: self.constness })
798 impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
799 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
800 self.map_bound(PredicateKind::Trait).to_predicate(tcx)
804 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
805 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
806 self.map_bound(PredicateKind::RegionOutlives).to_predicate(tcx)
810 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
811 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
812 self.map_bound(PredicateKind::TypeOutlives).to_predicate(tcx)
816 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
817 fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
818 self.map_bound(PredicateKind::Projection).to_predicate(tcx)
822 impl<'tcx> Predicate<'tcx> {
823 pub fn to_opt_poly_trait_ref(self) -> Option<ConstnessAnd<PolyTraitRef<'tcx>>> {
824 let predicate = self.kind();
825 match predicate.skip_binder() {
826 PredicateKind::Trait(t) => {
827 Some(ConstnessAnd { constness: t.constness, value: predicate.rebind(t.trait_ref) })
829 PredicateKind::Projection(..)
830 | PredicateKind::Subtype(..)
831 | PredicateKind::Coerce(..)
832 | PredicateKind::RegionOutlives(..)
833 | PredicateKind::WellFormed(..)
834 | PredicateKind::ObjectSafe(..)
835 | PredicateKind::ClosureKind(..)
836 | PredicateKind::TypeOutlives(..)
837 | PredicateKind::ConstEvaluatable(..)
838 | PredicateKind::ConstEquate(..)
839 | PredicateKind::TypeWellFormedFromEnv(..) => None,
843 pub fn to_opt_type_outlives(self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
844 let predicate = self.kind();
845 match predicate.skip_binder() {
846 PredicateKind::TypeOutlives(data) => Some(predicate.rebind(data)),
847 PredicateKind::Trait(..)
848 | PredicateKind::Projection(..)
849 | PredicateKind::Subtype(..)
850 | PredicateKind::Coerce(..)
851 | PredicateKind::RegionOutlives(..)
852 | PredicateKind::WellFormed(..)
853 | PredicateKind::ObjectSafe(..)
854 | PredicateKind::ClosureKind(..)
855 | PredicateKind::ConstEvaluatable(..)
856 | PredicateKind::ConstEquate(..)
857 | PredicateKind::TypeWellFormedFromEnv(..) => None,
862 /// Represents the bounds declared on a particular set of type
863 /// parameters. Should eventually be generalized into a flag list of
864 /// where-clauses. You can obtain an `InstantiatedPredicates` list from a
865 /// `GenericPredicates` by using the `instantiate` method. Note that this method
866 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
867 /// the `GenericPredicates` are expressed in terms of the bound type
868 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
869 /// represented a set of bounds for some particular instantiation,
870 /// meaning that the generic parameters have been substituted with
875 /// struct Foo<T, U: Bar<T>> { ... }
877 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
878 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
879 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
880 /// [usize:Bar<isize>]]`.
881 #[derive(Clone, Debug, TypeFoldable)]
882 pub struct InstantiatedPredicates<'tcx> {
883 pub predicates: Vec<Predicate<'tcx>>,
884 pub spans: Vec<Span>,
887 impl<'tcx> InstantiatedPredicates<'tcx> {
888 pub fn empty() -> InstantiatedPredicates<'tcx> {
889 InstantiatedPredicates { predicates: vec![], spans: vec![] }
892 pub fn is_empty(&self) -> bool {
893 self.predicates.is_empty()
897 #[derive(Copy, Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable, TypeFoldable)]
898 pub struct OpaqueTypeKey<'tcx> {
900 pub substs: SubstsRef<'tcx>,
903 rustc_index::newtype_index! {
904 /// "Universes" are used during type- and trait-checking in the
905 /// presence of `for<..>` binders to control what sets of names are
906 /// visible. Universes are arranged into a tree: the root universe
907 /// contains names that are always visible. Each child then adds a new
908 /// set of names that are visible, in addition to those of its parent.
909 /// We say that the child universe "extends" the parent universe with
912 /// To make this more concrete, consider this program:
916 /// fn bar<T>(x: T) {
917 /// let y: for<'a> fn(&'a u8, Foo) = ...;
921 /// The struct name `Foo` is in the root universe U0. But the type
922 /// parameter `T`, introduced on `bar`, is in an extended universe U1
923 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
924 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
925 /// region `'a` is in a universe U2 that extends U1, because we can
926 /// name it inside the fn type but not outside.
928 /// Universes are used to do type- and trait-checking around these
929 /// "forall" binders (also called **universal quantification**). The
930 /// idea is that when, in the body of `bar`, we refer to `T` as a
931 /// type, we aren't referring to any type in particular, but rather a
932 /// kind of "fresh" type that is distinct from all other types we have
933 /// actually declared. This is called a **placeholder** type, and we
934 /// use universes to talk about this. In other words, a type name in
935 /// universe 0 always corresponds to some "ground" type that the user
936 /// declared, but a type name in a non-zero universe is a placeholder
937 /// type -- an idealized representative of "types in general" that we
938 /// use for checking generic functions.
939 pub struct UniverseIndex {
941 DEBUG_FORMAT = "U{}",
946 pub const ROOT: UniverseIndex = UniverseIndex::from_u32(0);
948 /// Returns the "next" universe index in order -- this new index
949 /// is considered to extend all previous universes. This
950 /// corresponds to entering a `forall` quantifier. So, for
951 /// example, suppose we have this type in universe `U`:
954 /// for<'a> fn(&'a u32)
957 /// Once we "enter" into this `for<'a>` quantifier, we are in a
958 /// new universe that extends `U` -- in this new universe, we can
959 /// name the region `'a`, but that region was not nameable from
960 /// `U` because it was not in scope there.
961 pub fn next_universe(self) -> UniverseIndex {
962 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
965 /// Returns `true` if `self` can name a name from `other` -- in other words,
966 /// if the set of names in `self` is a superset of those in
967 /// `other` (`self >= other`).
968 pub fn can_name(self, other: UniverseIndex) -> bool {
969 self.private >= other.private
972 /// Returns `true` if `self` cannot name some names from `other` -- in other
973 /// words, if the set of names in `self` is a strict subset of
974 /// those in `other` (`self < other`).
975 pub fn cannot_name(self, other: UniverseIndex) -> bool {
976 self.private < other.private
980 /// The "placeholder index" fully defines a placeholder region, type, or const. Placeholders are
981 /// identified by both a universe, as well as a name residing within that universe. Distinct bound
982 /// regions/types/consts within the same universe simply have an unknown relationship to one
984 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, PartialOrd, Ord)]
985 pub struct Placeholder<T> {
986 pub universe: UniverseIndex,
990 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
992 T: HashStable<StableHashingContext<'a>>,
994 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
995 self.universe.hash_stable(hcx, hasher);
996 self.name.hash_stable(hcx, hasher);
1000 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
1002 pub type PlaceholderType = Placeholder<BoundVar>;
1004 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1005 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]
1006 pub struct BoundConst<'tcx> {
1011 pub type PlaceholderConst<'tcx> = Placeholder<BoundConst<'tcx>>;
1013 /// A `DefId` which, in case it is a const argument, is potentially bundled with
1014 /// the `DefId` of the generic parameter it instantiates.
1016 /// This is used to avoid calls to `type_of` for const arguments during typeck
1017 /// which cause cycle errors.
1022 /// fn foo<const N: usize>(&self) -> [u8; N] { [0; N] }
1023 /// // ^ const parameter
1027 /// fn foo<const M: u8>(&self) -> usize { 42 }
1028 /// // ^ const parameter
1033 /// let _b = a.foo::<{ 3 + 7 }>();
1034 /// // ^^^^^^^^^ const argument
1038 /// Let's look at the call `a.foo::<{ 3 + 7 }>()` here. We do not know
1039 /// which `foo` is used until we know the type of `a`.
1041 /// We only know the type of `a` once we are inside of `typeck(main)`.
1042 /// We also end up normalizing the type of `_b` during `typeck(main)` which
1043 /// requires us to evaluate the const argument.
1045 /// To evaluate that const argument we need to know its type,
1046 /// which we would get using `type_of(const_arg)`. This requires us to
1047 /// resolve `foo` as it can be either `usize` or `u8` in this example.
1048 /// However, resolving `foo` once again requires `typeck(main)` to get the type of `a`,
1049 /// which results in a cycle.
1051 /// In short we must not call `type_of(const_arg)` during `typeck(main)`.
1053 /// When first creating the `ty::Const` of the const argument inside of `typeck` we have
1054 /// already resolved `foo` so we know which const parameter this argument instantiates.
1055 /// This means that we also know the expected result of `type_of(const_arg)` even if we
1056 /// aren't allowed to call that query: it is equal to `type_of(const_param)` which is
1057 /// trivial to compute.
1059 /// If we now want to use that constant in a place which potentionally needs its type
1060 /// we also pass the type of its `const_param`. This is the point of `WithOptConstParam`,
1061 /// except that instead of a `Ty` we bundle the `DefId` of the const parameter.
1062 /// Meaning that we need to use `type_of(const_param_did)` if `const_param_did` is `Some`
1063 /// to get the type of `did`.
1064 #[derive(Copy, Clone, Debug, TypeFoldable, Lift, TyEncodable, TyDecodable)]
1065 #[derive(PartialEq, Eq, PartialOrd, Ord)]
1066 #[derive(Hash, HashStable)]
1067 pub struct WithOptConstParam<T> {
1069 /// The `DefId` of the corresponding generic parameter in case `did` is
1070 /// a const argument.
1072 /// Note that even if `did` is a const argument, this may still be `None`.
1073 /// All queries taking `WithOptConstParam` start by calling `tcx.opt_const_param_of(def.did)`
1074 /// to potentially update `param_did` in the case it is `None`.
1075 pub const_param_did: Option<DefId>,
1078 impl<T> WithOptConstParam<T> {
1079 /// Creates a new `WithOptConstParam` setting `const_param_did` to `None`.
1081 pub fn unknown(did: T) -> WithOptConstParam<T> {
1082 WithOptConstParam { did, const_param_did: None }
1086 impl WithOptConstParam<LocalDefId> {
1087 /// Returns `Some((did, param_did))` if `def_id` is a const argument,
1088 /// `None` otherwise.
1090 pub fn try_lookup(did: LocalDefId, tcx: TyCtxt<'_>) -> Option<(LocalDefId, DefId)> {
1091 tcx.opt_const_param_of(did).map(|param_did| (did, param_did))
1094 /// In case `self` is unknown but `self.did` is a const argument, this returns
1095 /// a `WithOptConstParam` with the correct `const_param_did`.
1097 pub fn try_upgrade(self, tcx: TyCtxt<'_>) -> Option<WithOptConstParam<LocalDefId>> {
1098 if self.const_param_did.is_none() {
1099 if let const_param_did @ Some(_) = tcx.opt_const_param_of(self.did) {
1100 return Some(WithOptConstParam { did: self.did, const_param_did });
1107 pub fn to_global(self) -> WithOptConstParam<DefId> {
1108 WithOptConstParam { did: self.did.to_def_id(), const_param_did: self.const_param_did }
1111 pub fn def_id_for_type_of(self) -> DefId {
1112 if let Some(did) = self.const_param_did { did } else { self.did.to_def_id() }
1116 impl WithOptConstParam<DefId> {
1117 pub fn as_local(self) -> Option<WithOptConstParam<LocalDefId>> {
1120 .map(|did| WithOptConstParam { did, const_param_did: self.const_param_did })
1123 pub fn as_const_arg(self) -> Option<(LocalDefId, DefId)> {
1124 if let Some(param_did) = self.const_param_did {
1125 if let Some(did) = self.did.as_local() {
1126 return Some((did, param_did));
1133 pub fn is_local(self) -> bool {
1137 pub fn def_id_for_type_of(self) -> DefId {
1138 self.const_param_did.unwrap_or(self.did)
1142 /// When type checking, we use the `ParamEnv` to track
1143 /// details about the set of where-clauses that are in scope at this
1144 /// particular point.
1145 #[derive(Copy, Clone, Hash, PartialEq, Eq)]
1146 pub struct ParamEnv<'tcx> {
1147 /// This packs both caller bounds and the reveal enum into one pointer.
1149 /// Caller bounds are `Obligation`s that the caller must satisfy. This is
1150 /// basically the set of bounds on the in-scope type parameters, translated
1151 /// into `Obligation`s, and elaborated and normalized.
1153 /// Use the `caller_bounds()` method to access.
1155 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1156 /// want `Reveal::All`.
1158 /// Note: This is packed, use the reveal() method to access it.
1159 packed: CopyTaggedPtr<&'tcx List<Predicate<'tcx>>, traits::Reveal, true>,
1162 unsafe impl rustc_data_structures::tagged_ptr::Tag for traits::Reveal {
1163 const BITS: usize = 1;
1165 fn into_usize(self) -> usize {
1167 traits::Reveal::UserFacing => 0,
1168 traits::Reveal::All => 1,
1172 unsafe fn from_usize(ptr: usize) -> Self {
1174 0 => traits::Reveal::UserFacing,
1175 1 => traits::Reveal::All,
1176 _ => std::hint::unreachable_unchecked(),
1181 impl<'tcx> fmt::Debug for ParamEnv<'tcx> {
1182 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1183 f.debug_struct("ParamEnv")
1184 .field("caller_bounds", &self.caller_bounds())
1185 .field("reveal", &self.reveal())
1190 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ParamEnv<'tcx> {
1191 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1192 self.caller_bounds().hash_stable(hcx, hasher);
1193 self.reveal().hash_stable(hcx, hasher);
1197 impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
1198 fn super_fold_with<F: ty::fold::TypeFolder<'tcx>>(self, folder: &mut F) -> Self {
1199 ParamEnv::new(self.caller_bounds().fold_with(folder), self.reveal().fold_with(folder))
1202 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
1203 self.caller_bounds().visit_with(visitor)?;
1204 self.reveal().visit_with(visitor)
1208 impl<'tcx> ParamEnv<'tcx> {
1209 /// Construct a trait environment suitable for contexts where
1210 /// there are no where-clauses in scope. Hidden types (like `impl
1211 /// Trait`) are left hidden, so this is suitable for ordinary
1214 pub fn empty() -> Self {
1215 Self::new(List::empty(), Reveal::UserFacing)
1219 pub fn caller_bounds(self) -> &'tcx List<Predicate<'tcx>> {
1220 self.packed.pointer()
1224 pub fn reveal(self) -> traits::Reveal {
1228 /// Construct a trait environment with no where-clauses in scope
1229 /// where the values of all `impl Trait` and other hidden types
1230 /// are revealed. This is suitable for monomorphized, post-typeck
1231 /// environments like codegen or doing optimizations.
1233 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1234 /// or invoke `param_env.with_reveal_all()`.
1236 pub fn reveal_all() -> Self {
1237 Self::new(List::empty(), Reveal::All)
1240 /// Construct a trait environment with the given set of predicates.
1242 pub fn new(caller_bounds: &'tcx List<Predicate<'tcx>>, reveal: Reveal) -> Self {
1243 ty::ParamEnv { packed: CopyTaggedPtr::new(caller_bounds, reveal) }
1246 pub fn with_user_facing(mut self) -> Self {
1247 self.packed.set_tag(Reveal::UserFacing);
1251 /// Returns a new parameter environment with the same clauses, but
1252 /// which "reveals" the true results of projections in all cases
1253 /// (even for associated types that are specializable). This is
1254 /// the desired behavior during codegen and certain other special
1255 /// contexts; normally though we want to use `Reveal::UserFacing`,
1256 /// which is the default.
1257 /// All opaque types in the caller_bounds of the `ParamEnv`
1258 /// will be normalized to their underlying types.
1259 /// See PR #65989 and issue #65918 for more details
1260 pub fn with_reveal_all_normalized(self, tcx: TyCtxt<'tcx>) -> Self {
1261 if self.packed.tag() == traits::Reveal::All {
1265 ParamEnv::new(tcx.normalize_opaque_types(self.caller_bounds()), Reveal::All)
1268 /// Returns this same environment but with no caller bounds.
1270 pub fn without_caller_bounds(self) -> Self {
1271 Self::new(List::empty(), self.reveal())
1274 /// Creates a suitable environment in which to perform trait
1275 /// queries on the given value. When type-checking, this is simply
1276 /// the pair of the environment plus value. But when reveal is set to
1277 /// All, then if `value` does not reference any type parameters, we will
1278 /// pair it with the empty environment. This improves caching and is generally
1281 /// N.B., we preserve the environment when type-checking because it
1282 /// is possible for the user to have wacky where-clauses like
1283 /// `where Box<u32>: Copy`, which are clearly never
1284 /// satisfiable. We generally want to behave as if they were true,
1285 /// although the surrounding function is never reachable.
1286 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1287 match self.reveal() {
1288 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1291 if value.is_known_global() {
1292 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1294 ParamEnvAnd { param_env: self, value }
1301 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1302 pub struct ConstnessAnd<T> {
1303 pub constness: BoundConstness,
1307 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
1308 // the constness of trait bounds is being propagated correctly.
1309 pub trait WithConstness: Sized {
1311 fn with_constness(self, constness: BoundConstness) -> ConstnessAnd<Self> {
1312 ConstnessAnd { constness, value: self }
1316 fn with_const_if_const(self) -> ConstnessAnd<Self> {
1317 self.with_constness(BoundConstness::ConstIfConst)
1321 fn without_const(self) -> ConstnessAnd<Self> {
1322 self.with_constness(BoundConstness::NotConst)
1326 impl<T> WithConstness for T {}
1328 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1329 pub struct ParamEnvAnd<'tcx, T> {
1330 pub param_env: ParamEnv<'tcx>,
1334 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1335 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1336 (self.param_env, self.value)
1340 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1342 T: HashStable<StableHashingContext<'a>>,
1344 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1345 let ParamEnvAnd { ref param_env, ref value } = *self;
1347 param_env.hash_stable(hcx, hasher);
1348 value.hash_stable(hcx, hasher);
1352 #[derive(Copy, Clone, Debug, HashStable)]
1353 pub struct Destructor {
1354 /// The `DefId` of the destructor method
1356 /// The constness of the destructor method
1357 pub constness: hir::Constness,
1361 #[derive(HashStable)]
1362 pub struct VariantFlags: u32 {
1363 const NO_VARIANT_FLAGS = 0;
1364 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1365 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1366 /// Indicates whether this variant was obtained as part of recovering from
1367 /// a syntactic error. May be incomplete or bogus.
1368 const IS_RECOVERED = 1 << 1;
1372 /// Definition of a variant -- a struct's fields or an enum variant.
1373 #[derive(Debug, HashStable)]
1374 pub struct VariantDef {
1375 /// `DefId` that identifies the variant itself.
1376 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1378 /// `DefId` that identifies the variant's constructor.
1379 /// If this variant is a struct variant, then this is `None`.
1380 pub ctor_def_id: Option<DefId>,
1381 /// Variant or struct name.
1382 #[stable_hasher(project(name))]
1384 /// Discriminant of this variant.
1385 pub discr: VariantDiscr,
1386 /// Fields of this variant.
1387 pub fields: Vec<FieldDef>,
1388 /// Type of constructor of variant.
1389 pub ctor_kind: CtorKind,
1390 /// Flags of the variant (e.g. is field list non-exhaustive)?
1391 flags: VariantFlags,
1395 /// Creates a new `VariantDef`.
1397 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1398 /// represents an enum variant).
1400 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1401 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1403 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1404 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1405 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1406 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1407 /// built-in trait), and we do not want to load attributes twice.
1409 /// If someone speeds up attribute loading to not be a performance concern, they can
1410 /// remove this hack and use the constructor `DefId` everywhere.
1413 variant_did: Option<DefId>,
1414 ctor_def_id: Option<DefId>,
1415 discr: VariantDiscr,
1416 fields: Vec<FieldDef>,
1417 ctor_kind: CtorKind,
1421 is_field_list_non_exhaustive: bool,
1424 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1425 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1426 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1429 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1430 if is_field_list_non_exhaustive {
1431 flags |= VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1435 flags |= VariantFlags::IS_RECOVERED;
1439 def_id: variant_did.unwrap_or(parent_did),
1449 /// Is this field list non-exhaustive?
1451 pub fn is_field_list_non_exhaustive(&self) -> bool {
1452 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1455 /// Was this variant obtained as part of recovering from a syntactic error?
1457 pub fn is_recovered(&self) -> bool {
1458 self.flags.intersects(VariantFlags::IS_RECOVERED)
1462 #[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, HashStable)]
1463 pub enum VariantDiscr {
1464 /// Explicit value for this variant, i.e., `X = 123`.
1465 /// The `DefId` corresponds to the embedded constant.
1468 /// The previous variant's discriminant plus one.
1469 /// For efficiency reasons, the distance from the
1470 /// last `Explicit` discriminant is being stored,
1471 /// or `0` for the first variant, if it has none.
1475 #[derive(Debug, HashStable)]
1476 pub struct FieldDef {
1478 #[stable_hasher(project(name))]
1480 pub vis: Visibility,
1484 #[derive(TyEncodable, TyDecodable, Default, HashStable)]
1485 pub struct ReprFlags: u8 {
1486 const IS_C = 1 << 0;
1487 const IS_SIMD = 1 << 1;
1488 const IS_TRANSPARENT = 1 << 2;
1489 // Internal only for now. If true, don't reorder fields.
1490 const IS_LINEAR = 1 << 3;
1491 // If true, don't expose any niche to type's context.
1492 const HIDE_NICHE = 1 << 4;
1493 // If true, the type's layout can be randomized using
1494 // the seed stored in `ReprOptions.layout_seed`
1495 const RANDOMIZE_LAYOUT = 1 << 5;
1496 // Any of these flags being set prevent field reordering optimisation.
1497 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1498 ReprFlags::IS_SIMD.bits |
1499 ReprFlags::IS_LINEAR.bits;
1503 /// Represents the repr options provided by the user,
1504 #[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Default, HashStable)]
1505 pub struct ReprOptions {
1506 pub int: Option<attr::IntType>,
1507 pub align: Option<Align>,
1508 pub pack: Option<Align>,
1509 pub flags: ReprFlags,
1510 /// The seed to be used for randomizing a type's layout
1512 /// Note: This could technically be a `[u8; 16]` (a `u128`) which would
1513 /// be the "most accurate" hash as it'd encompass the item and crate
1514 /// hash without loss, but it does pay the price of being larger.
1515 /// Everything's a tradeoff, a `u64` seed should be sufficient for our
1516 /// purposes (primarily `-Z randomize-layout`)
1517 pub field_shuffle_seed: u64,
1521 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
1522 let mut flags = ReprFlags::empty();
1523 let mut size = None;
1524 let mut max_align: Option<Align> = None;
1525 let mut min_pack: Option<Align> = None;
1527 // Generate a deterministically-derived seed from the item's path hash
1528 // to allow for cross-crate compilation to actually work
1529 let field_shuffle_seed = tcx.def_path_hash(did).0.to_smaller_hash();
1531 for attr in tcx.get_attrs(did).iter() {
1532 for r in attr::find_repr_attrs(&tcx.sess, attr) {
1533 flags.insert(match r {
1534 attr::ReprC => ReprFlags::IS_C,
1535 attr::ReprPacked(pack) => {
1536 let pack = Align::from_bytes(pack as u64).unwrap();
1537 min_pack = Some(if let Some(min_pack) = min_pack {
1544 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1545 attr::ReprNoNiche => ReprFlags::HIDE_NICHE,
1546 attr::ReprSimd => ReprFlags::IS_SIMD,
1547 attr::ReprInt(i) => {
1551 attr::ReprAlign(align) => {
1552 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
1559 // If `-Z randomize-layout` was enabled for the type definition then we can
1560 // consider performing layout randomization
1561 if tcx.sess.opts.debugging_opts.randomize_layout {
1562 flags.insert(ReprFlags::RANDOMIZE_LAYOUT);
1565 // This is here instead of layout because the choice must make it into metadata.
1566 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
1567 flags.insert(ReprFlags::IS_LINEAR);
1570 Self { int: size, align: max_align, pack: min_pack, flags, field_shuffle_seed }
1574 pub fn simd(&self) -> bool {
1575 self.flags.contains(ReprFlags::IS_SIMD)
1579 pub fn c(&self) -> bool {
1580 self.flags.contains(ReprFlags::IS_C)
1584 pub fn packed(&self) -> bool {
1589 pub fn transparent(&self) -> bool {
1590 self.flags.contains(ReprFlags::IS_TRANSPARENT)
1594 pub fn linear(&self) -> bool {
1595 self.flags.contains(ReprFlags::IS_LINEAR)
1599 pub fn hide_niche(&self) -> bool {
1600 self.flags.contains(ReprFlags::HIDE_NICHE)
1603 /// Returns the discriminant type, given these `repr` options.
1604 /// This must only be called on enums!
1605 pub fn discr_type(&self) -> attr::IntType {
1606 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1609 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
1610 /// layout" optimizations, such as representing `Foo<&T>` as a
1612 pub fn inhibit_enum_layout_opt(&self) -> bool {
1613 self.c() || self.int.is_some()
1616 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
1617 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
1618 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1619 if let Some(pack) = self.pack {
1620 if pack.bytes() == 1 {
1625 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
1628 /// Returns `true` if this type is valid for reordering and `-Z randomize-layout`
1629 /// was enabled for its declaration crate
1630 pub fn can_randomize_type_layout(&self) -> bool {
1631 !self.inhibit_struct_field_reordering_opt()
1632 && self.flags.contains(ReprFlags::RANDOMIZE_LAYOUT)
1635 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
1636 pub fn inhibit_union_abi_opt(&self) -> bool {
1641 impl<'tcx> FieldDef {
1642 /// Returns the type of this field. The resulting type is not normalized. The `subst` is
1643 /// typically obtained via the second field of `TyKind::AdtDef`.
1644 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
1645 tcx.type_of(self.did).subst(tcx, subst)
1649 pub type Attributes<'tcx> = &'tcx [ast::Attribute];
1651 #[derive(Debug, PartialEq, Eq)]
1652 pub enum ImplOverlapKind {
1653 /// These impls are always allowed to overlap.
1655 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
1658 /// These impls are allowed to overlap, but that raises
1659 /// an issue #33140 future-compatibility warning.
1661 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
1662 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
1664 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
1665 /// that difference, making what reduces to the following set of impls:
1669 /// impl Trait for dyn Send + Sync {}
1670 /// impl Trait for dyn Sync + Send {}
1673 /// Obviously, once we made these types be identical, that code causes a coherence
1674 /// error and a fairly big headache for us. However, luckily for us, the trait
1675 /// `Trait` used in this case is basically a marker trait, and therefore having
1676 /// overlapping impls for it is sound.
1678 /// To handle this, we basically regard the trait as a marker trait, with an additional
1679 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
1680 /// it has the following restrictions:
1682 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
1684 /// 2. The trait-ref of both impls must be equal.
1685 /// 3. The trait-ref of both impls must be a trait object type consisting only of
1687 /// 4. Neither of the impls can have any where-clauses.
1689 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
1693 impl<'tcx> TyCtxt<'tcx> {
1694 pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> {
1695 self.typeck(self.hir().body_owner_def_id(body))
1698 pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
1699 self.associated_items(id)
1700 .in_definition_order()
1701 .filter(|item| item.kind == AssocKind::Fn && item.defaultness.has_value())
1704 fn item_name_from_hir(self, def_id: DefId) -> Option<Ident> {
1705 self.hir().get_if_local(def_id).and_then(|node| node.ident())
1708 fn item_name_from_def_id(self, def_id: DefId) -> Option<Symbol> {
1709 if def_id.index == CRATE_DEF_INDEX {
1710 Some(self.crate_name(def_id.krate))
1712 let def_key = self.def_key(def_id);
1713 match def_key.disambiguated_data.data {
1714 // The name of a constructor is that of its parent.
1715 rustc_hir::definitions::DefPathData::Ctor => self.item_name_from_def_id(DefId {
1716 krate: def_id.krate,
1717 index: def_key.parent.unwrap(),
1719 _ => def_key.disambiguated_data.data.get_opt_name(),
1724 /// Look up the name of an item across crates. This does not look at HIR.
1726 /// When possible, this function should be used for cross-crate lookups over
1727 /// [`opt_item_name`] to avoid invalidating the incremental cache. If you
1728 /// need to handle items without a name, or HIR items that will not be
1729 /// serialized cross-crate, or if you need the span of the item, use
1730 /// [`opt_item_name`] instead.
1732 /// [`opt_item_name`]: Self::opt_item_name
1733 pub fn item_name(self, id: DefId) -> Symbol {
1734 // Look at cross-crate items first to avoid invalidating the incremental cache
1735 // unless we have to.
1736 self.item_name_from_def_id(id).unwrap_or_else(|| {
1737 bug!("item_name: no name for {:?}", self.def_path(id));
1741 /// Look up the name and span of an item or [`Node`].
1743 /// See [`item_name`][Self::item_name] for more information.
1744 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
1745 // Look at the HIR first so the span will be correct if this is a local item.
1746 self.item_name_from_hir(def_id)
1747 .or_else(|| self.item_name_from_def_id(def_id).map(Ident::with_dummy_span))
1750 pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> {
1751 if let DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy = self.def_kind(def_id) {
1752 Some(self.associated_item(def_id))
1758 pub fn field_index(self, hir_id: hir::HirId, typeck_results: &TypeckResults<'_>) -> usize {
1759 typeck_results.field_indices().get(hir_id).cloned().expect("no index for a field")
1762 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
1763 variant.fields.iter().position(|field| self.hygienic_eq(ident, field.ident, variant.def_id))
1766 /// Returns `true` if the impls are the same polarity and the trait either
1767 /// has no items or is annotated `#[marker]` and prevents item overrides.
1768 pub fn impls_are_allowed_to_overlap(
1772 ) -> Option<ImplOverlapKind> {
1773 // If either trait impl references an error, they're allowed to overlap,
1774 // as one of them essentially doesn't exist.
1775 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
1776 || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
1778 return Some(ImplOverlapKind::Permitted { marker: false });
1781 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
1782 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
1783 // `#[rustc_reservation_impl]` impls don't overlap with anything
1785 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
1788 return Some(ImplOverlapKind::Permitted { marker: false });
1790 (ImplPolarity::Positive, ImplPolarity::Negative)
1791 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
1792 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
1794 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
1799 (ImplPolarity::Positive, ImplPolarity::Positive)
1800 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
1803 let is_marker_overlap = {
1804 let is_marker_impl = |def_id: DefId| -> bool {
1805 let trait_ref = self.impl_trait_ref(def_id);
1806 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
1808 is_marker_impl(def_id1) && is_marker_impl(def_id2)
1811 if is_marker_overlap {
1813 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
1816 Some(ImplOverlapKind::Permitted { marker: true })
1818 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
1819 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
1820 if self_ty1 == self_ty2 {
1822 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
1825 return Some(ImplOverlapKind::Issue33140);
1828 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
1829 def_id1, def_id2, self_ty1, self_ty2
1835 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
1840 /// Returns `ty::VariantDef` if `res` refers to a struct,
1841 /// or variant or their constructors, panics otherwise.
1842 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
1844 Res::Def(DefKind::Variant, did) => {
1845 let enum_did = self.parent(did).unwrap();
1846 self.adt_def(enum_did).variant_with_id(did)
1848 Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(),
1849 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
1850 let variant_did = self.parent(variant_ctor_did).unwrap();
1851 let enum_did = self.parent(variant_did).unwrap();
1852 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
1854 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
1855 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
1856 self.adt_def(struct_did).non_enum_variant()
1858 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
1862 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
1863 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
1865 ty::InstanceDef::Item(def) => match self.def_kind(def.did) {
1868 | DefKind::AssocConst
1870 | DefKind::AnonConst => self.mir_for_ctfe_opt_const_arg(def),
1871 // If the caller wants `mir_for_ctfe` of a function they should not be using
1872 // `instance_mir`, so we'll assume const fn also wants the optimized version.
1874 assert_eq!(def.const_param_did, None);
1875 self.optimized_mir(def.did)
1878 ty::InstanceDef::VtableShim(..)
1879 | ty::InstanceDef::ReifyShim(..)
1880 | ty::InstanceDef::Intrinsic(..)
1881 | ty::InstanceDef::FnPtrShim(..)
1882 | ty::InstanceDef::Virtual(..)
1883 | ty::InstanceDef::ClosureOnceShim { .. }
1884 | ty::InstanceDef::DropGlue(..)
1885 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance),
1889 /// Gets the attributes of a definition.
1890 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
1891 if let Some(did) = did.as_local() {
1892 self.hir().attrs(self.hir().local_def_id_to_hir_id(did))
1894 self.item_attrs(did)
1898 /// Determines whether an item is annotated with an attribute.
1899 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
1900 self.sess.contains_name(&self.get_attrs(did), attr)
1903 /// Determines whether an item is annotated with `doc(hidden)`.
1904 pub fn is_doc_hidden(self, did: DefId) -> bool {
1907 .filter_map(|attr| if attr.has_name(sym::doc) { attr.meta_item_list() } else { None })
1908 .any(|items| items.iter().any(|item| item.has_name(sym::hidden)))
1911 /// Returns `true` if this is an `auto trait`.
1912 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
1913 self.trait_def(trait_def_id).has_auto_impl
1916 /// Returns layout of a generator. Layout might be unavailable if the
1917 /// generator is tainted by errors.
1918 pub fn generator_layout(self, def_id: DefId) -> Option<&'tcx GeneratorLayout<'tcx>> {
1919 self.optimized_mir(def_id).generator_layout()
1922 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
1923 /// If it implements no trait, returns `None`.
1924 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
1925 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
1928 /// If the given defid describes a method belonging to an impl, returns the
1929 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
1930 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
1931 self.opt_associated_item(def_id).and_then(|trait_item| match trait_item.container {
1932 TraitContainer(_) => None,
1933 ImplContainer(def_id) => Some(def_id),
1937 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
1938 /// with the name of the crate containing the impl.
1939 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
1940 if let Some(impl_did) = impl_did.as_local() {
1941 let hir_id = self.hir().local_def_id_to_hir_id(impl_did);
1942 Ok(self.hir().span(hir_id))
1944 Err(self.crate_name(impl_did.krate))
1948 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
1949 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
1950 /// definition's parent/scope to perform comparison.
1951 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
1952 // We could use `Ident::eq` here, but we deliberately don't. The name
1953 // comparison fails frequently, and we want to avoid the expensive
1954 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
1955 use_name.name == def_name.name
1959 .hygienic_eq(def_name.span.ctxt(), self.expn_that_defined(def_parent_def_id))
1962 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
1963 ident.span.normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope));
1967 pub fn adjust_ident_and_get_scope(
1972 ) -> (Ident, DefId) {
1975 .normalize_to_macros_2_0_and_adjust(self.expn_that_defined(scope))
1976 .and_then(|actual_expansion| actual_expansion.expn_data().parent_module)
1977 .unwrap_or_else(|| self.parent_module(block).to_def_id());
1981 pub fn is_object_safe(self, key: DefId) -> bool {
1982 self.object_safety_violations(key).is_empty()
1986 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
1987 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
1988 if let Some(def_id) = def_id.as_local() {
1989 if let Node::Item(item) = tcx.hir().get(tcx.hir().local_def_id_to_hir_id(def_id)) {
1990 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
1991 return opaque_ty.impl_trait_fn;
1998 pub fn int_ty(ity: ast::IntTy) -> IntTy {
2000 ast::IntTy::Isize => IntTy::Isize,
2001 ast::IntTy::I8 => IntTy::I8,
2002 ast::IntTy::I16 => IntTy::I16,
2003 ast::IntTy::I32 => IntTy::I32,
2004 ast::IntTy::I64 => IntTy::I64,
2005 ast::IntTy::I128 => IntTy::I128,
2009 pub fn uint_ty(uty: ast::UintTy) -> UintTy {
2011 ast::UintTy::Usize => UintTy::Usize,
2012 ast::UintTy::U8 => UintTy::U8,
2013 ast::UintTy::U16 => UintTy::U16,
2014 ast::UintTy::U32 => UintTy::U32,
2015 ast::UintTy::U64 => UintTy::U64,
2016 ast::UintTy::U128 => UintTy::U128,
2020 pub fn float_ty(fty: ast::FloatTy) -> FloatTy {
2022 ast::FloatTy::F32 => FloatTy::F32,
2023 ast::FloatTy::F64 => FloatTy::F64,
2027 pub fn ast_int_ty(ity: IntTy) -> ast::IntTy {
2029 IntTy::Isize => ast::IntTy::Isize,
2030 IntTy::I8 => ast::IntTy::I8,
2031 IntTy::I16 => ast::IntTy::I16,
2032 IntTy::I32 => ast::IntTy::I32,
2033 IntTy::I64 => ast::IntTy::I64,
2034 IntTy::I128 => ast::IntTy::I128,
2038 pub fn ast_uint_ty(uty: UintTy) -> ast::UintTy {
2040 UintTy::Usize => ast::UintTy::Usize,
2041 UintTy::U8 => ast::UintTy::U8,
2042 UintTy::U16 => ast::UintTy::U16,
2043 UintTy::U32 => ast::UintTy::U32,
2044 UintTy::U64 => ast::UintTy::U64,
2045 UintTy::U128 => ast::UintTy::U128,
2049 pub fn provide(providers: &mut ty::query::Providers) {
2050 closure::provide(providers);
2051 context::provide(providers);
2052 erase_regions::provide(providers);
2053 layout::provide(providers);
2054 util::provide(providers);
2055 print::provide(providers);
2056 super::util::bug::provide(providers);
2057 super::middle::provide(providers);
2058 *providers = ty::query::Providers {
2059 trait_impls_of: trait_def::trait_impls_of_provider,
2060 type_uninhabited_from: inhabitedness::type_uninhabited_from,
2061 const_param_default: consts::const_param_default,
2062 vtable_allocation: vtable::vtable_allocation_provider,
2067 /// A map for the local crate mapping each type to a vector of its
2068 /// inherent impls. This is not meant to be used outside of coherence;
2069 /// rather, you should request the vector for a specific type via
2070 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2071 /// (constructing this map requires touching the entire crate).
2072 #[derive(Clone, Debug, Default, HashStable)]
2073 pub struct CrateInherentImpls {
2074 pub inherent_impls: LocalDefIdMap<Vec<DefId>>,
2077 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]
2078 pub struct SymbolName<'tcx> {
2079 /// `&str` gives a consistent ordering, which ensures reproducible builds.
2080 pub name: &'tcx str,
2083 impl<'tcx> SymbolName<'tcx> {
2084 pub fn new(tcx: TyCtxt<'tcx>, name: &str) -> SymbolName<'tcx> {
2086 name: unsafe { str::from_utf8_unchecked(tcx.arena.alloc_slice(name.as_bytes())) },
2091 impl<'tcx> fmt::Display for SymbolName<'tcx> {
2092 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2093 fmt::Display::fmt(&self.name, fmt)
2097 impl<'tcx> fmt::Debug for SymbolName<'tcx> {
2098 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2099 fmt::Display::fmt(&self.name, fmt)
2103 #[derive(Debug, Default, Copy, Clone)]
2104 pub struct FoundRelationships {
2105 /// This is true if we identified that this Ty (`?T`) is found in a `?T: Foo`
2106 /// obligation, where:
2108 /// * `Foo` is not `Sized`
2109 /// * `(): Foo` may be satisfied
2110 pub self_in_trait: bool,
2111 /// This is true if we identified that this Ty (`?T`) is found in a `<_ as
2112 /// _>::AssocType = ?T`