1 pub use self::fold::{TypeFoldable, TypeVisitor};
2 pub use self::AssocItemContainer::*;
3 pub use self::BorrowKind::*;
4 pub use self::IntVarValue::*;
5 pub use self::Variance::*;
7 use crate::hir::exports::ExportMap;
8 use crate::ich::StableHashingContext;
9 use crate::infer::canonical::Canonical;
10 use crate::middle::cstore::CrateStoreDyn;
11 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
12 use crate::mir::interpret::ErrorHandled;
14 use crate::mir::GeneratorLayout;
15 use crate::traits::{self, Reveal};
17 use crate::ty::subst::{InternalSubsts, Subst, SubstsRef};
18 use crate::ty::util::{Discr, IntTypeExt};
20 use rustc_ast::node_id::{NodeId, NodeMap, NodeSet};
21 use rustc_attr as attr;
22 use rustc_data_structures::captures::Captures;
23 use rustc_data_structures::fingerprint::Fingerprint;
24 use rustc_data_structures::fx::FxHashMap;
25 use rustc_data_structures::fx::FxIndexMap;
26 use rustc_data_structures::sorted_map::SortedIndexMultiMap;
27 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
28 use rustc_data_structures::sync::{self, par_iter, ParallelIterator};
29 use rustc_errors::ErrorReported;
31 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Namespace, Res};
32 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
33 use rustc_hir::lang_items::{FnMutTraitLangItem, FnOnceTraitLangItem, FnTraitLangItem};
34 use rustc_hir::{Constness, GlobMap, Node, TraitMap};
35 use rustc_index::vec::{Idx, IndexVec};
36 use rustc_macros::HashStable;
37 use rustc_serialize::{self, Encodable, Encoder};
38 use rustc_session::DataTypeKind;
39 use rustc_span::hygiene::ExpnId;
40 use rustc_span::symbol::{kw, sym, Ident, Symbol};
42 use rustc_target::abi::{Align, VariantIdx};
44 use std::cell::RefCell;
45 use std::cmp::Ordering;
47 use std::hash::{Hash, Hasher};
51 pub use self::sty::BoundRegion::*;
52 pub use self::sty::InferTy::*;
53 pub use self::sty::RegionKind;
54 pub use self::sty::RegionKind::*;
55 pub use self::sty::TyKind::*;
56 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
57 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
58 pub use self::sty::{CanonicalPolyFnSig, FnSig, GenSig, PolyFnSig, PolyGenSig};
59 pub use self::sty::{ClosureSubsts, GeneratorSubsts, TypeAndMut, UpvarSubsts};
60 pub use self::sty::{Const, ConstKind, ExistentialProjection, PolyExistentialProjection};
61 pub use self::sty::{ConstVid, FloatVid, IntVid, RegionVid, TyVid};
62 pub use self::sty::{ExistentialPredicate, InferConst, InferTy, ParamConst, ParamTy, ProjectionTy};
63 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
64 pub use self::sty::{PolyTraitRef, TraitRef, TyKind};
65 pub use crate::ty::diagnostics::*;
67 pub use self::binding::BindingMode;
68 pub use self::binding::BindingMode::*;
70 pub use self::context::{tls, FreeRegionInfo, TyCtxt};
71 pub use self::context::{
72 CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
73 UserType, UserTypeAnnotationIndex,
75 pub use self::context::{
76 CtxtInterners, GeneratorInteriorTypeCause, GlobalCtxt, Lift, TypeckTables,
79 pub use self::instance::{Instance, InstanceDef};
81 pub use self::list::List;
83 pub use self::trait_def::TraitDef;
85 pub use self::query::queries;
98 pub mod inhabitedness;
100 pub mod normalize_erasing_regions;
115 mod structural_impls;
120 pub struct ResolverOutputs {
121 pub definitions: rustc_hir::definitions::Definitions,
122 pub cstore: Box<CrateStoreDyn>,
123 pub extern_crate_map: NodeMap<CrateNum>,
124 pub trait_map: TraitMap<NodeId>,
125 pub maybe_unused_trait_imports: NodeSet,
126 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
127 pub export_map: ExportMap<NodeId>,
128 pub glob_map: GlobMap,
129 /// Extern prelude entries. The value is `true` if the entry was introduced
130 /// via `extern crate` item and not `--extern` option or compiler built-in.
131 pub extern_prelude: FxHashMap<Symbol, bool>,
134 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
135 pub enum AssocItemContainer {
136 TraitContainer(DefId),
137 ImplContainer(DefId),
140 impl AssocItemContainer {
141 /// Asserts that this is the `DefId` of an associated item declared
142 /// in a trait, and returns the trait `DefId`.
143 pub fn assert_trait(&self) -> DefId {
145 TraitContainer(id) => id,
146 _ => bug!("associated item has wrong container type: {:?}", self),
150 pub fn id(&self) -> DefId {
152 TraitContainer(id) => id,
153 ImplContainer(id) => id,
158 /// The "header" of an impl is everything outside the body: a Self type, a trait
159 /// ref (in the case of a trait impl), and a set of predicates (from the
160 /// bounds / where-clauses).
161 #[derive(Clone, Debug, TypeFoldable)]
162 pub struct ImplHeader<'tcx> {
163 pub impl_def_id: DefId,
164 pub self_ty: Ty<'tcx>,
165 pub trait_ref: Option<TraitRef<'tcx>>,
166 pub predicates: Vec<Predicate<'tcx>>,
169 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
170 pub enum ImplPolarity {
171 /// `impl Trait for Type`
173 /// `impl !Trait for Type`
175 /// `#[rustc_reservation_impl] impl Trait for Type`
177 /// This is a "stability hack", not a real Rust feature.
178 /// See #64631 for details.
182 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
183 pub struct AssocItem {
185 #[stable_hasher(project(name))]
189 pub defaultness: hir::Defaultness,
190 pub container: AssocItemContainer,
192 /// Whether this is a method with an explicit self
193 /// as its first parameter, allowing method calls.
194 pub fn_has_self_parameter: bool,
197 #[derive(Copy, Clone, PartialEq, Debug, HashStable)]
206 pub fn namespace(&self) -> Namespace {
208 ty::AssocKind::OpaqueTy | ty::AssocKind::Type => Namespace::TypeNS,
209 ty::AssocKind::Const | ty::AssocKind::Fn => Namespace::ValueNS,
213 pub fn as_def_kind(&self) -> DefKind {
215 AssocKind::Const => DefKind::AssocConst,
216 AssocKind::Fn => DefKind::AssocFn,
217 AssocKind::Type => DefKind::AssocTy,
218 AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
224 /// Tests whether the associated item admits a non-trivial implementation
226 pub fn relevant_for_never(&self) -> bool {
228 AssocKind::OpaqueTy | AssocKind::Const | AssocKind::Type => true,
229 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
230 AssocKind::Fn => !self.fn_has_self_parameter,
234 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
236 ty::AssocKind::Fn => {
237 // We skip the binder here because the binder would deanonymize all
238 // late-bound regions, and we don't want method signatures to show up
239 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
240 // regions just fine, showing `fn(&MyType)`.
241 tcx.fn_sig(self.def_id).skip_binder().to_string()
243 ty::AssocKind::Type => format!("type {};", self.ident),
244 // FIXME(type_alias_impl_trait): we should print bounds here too.
245 ty::AssocKind::OpaqueTy => format!("type {};", self.ident),
246 ty::AssocKind::Const => {
247 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
253 /// A list of `ty::AssocItem`s in definition order that allows for efficient lookup by name.
255 /// When doing lookup by name, we try to postpone hygienic comparison for as long as possible since
256 /// it is relatively expensive. Instead, items are indexed by `Symbol` and hygienic comparison is
257 /// done only on items with the same name.
258 #[derive(Debug, Clone, PartialEq, HashStable)]
259 pub struct AssociatedItems<'tcx> {
260 items: SortedIndexMultiMap<u32, Symbol, &'tcx ty::AssocItem>,
263 impl<'tcx> AssociatedItems<'tcx> {
264 /// Constructs an `AssociatedItems` map from a series of `ty::AssocItem`s in definition order.
265 pub fn new(items_in_def_order: impl IntoIterator<Item = &'tcx ty::AssocItem>) -> Self {
266 let items = items_in_def_order.into_iter().map(|item| (item.ident.name, item)).collect();
267 AssociatedItems { items }
270 /// Returns a slice of associated items in the order they were defined.
272 /// New code should avoid relying on definition order. If you need a particular associated item
273 /// for a known trait, make that trait a lang item instead of indexing this array.
274 pub fn in_definition_order(&self) -> impl '_ + Iterator<Item = &ty::AssocItem> {
275 self.items.iter().map(|(_, v)| *v)
278 /// Returns an iterator over all associated items with the given name, ignoring hygiene.
279 pub fn filter_by_name_unhygienic(
282 ) -> impl '_ + Iterator<Item = &ty::AssocItem> {
283 self.items.get_by_key(&name).copied()
286 /// Returns an iterator over all associated items with the given name.
288 /// Multiple items may have the same name if they are in different `Namespace`s. For example,
289 /// an associated type can have the same name as a method. Use one of the `find_by_name_and_*`
290 /// methods below if you know which item you are looking for.
291 pub fn filter_by_name(
295 parent_def_id: DefId,
296 ) -> impl 'a + Iterator<Item = &'a ty::AssocItem> {
297 self.filter_by_name_unhygienic(ident.name)
298 .filter(move |item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
301 /// Returns the associated item with the given name and `AssocKind`, if one exists.
302 pub fn find_by_name_and_kind(
307 parent_def_id: DefId,
308 ) -> Option<&ty::AssocItem> {
309 self.filter_by_name_unhygienic(ident.name)
310 .filter(|item| item.kind == kind)
311 .find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
314 /// Returns the associated item with the given name in the given `Namespace`, if one exists.
315 pub fn find_by_name_and_namespace(
320 parent_def_id: DefId,
321 ) -> Option<&ty::AssocItem> {
322 self.filter_by_name_unhygienic(ident.name)
323 .filter(|item| item.kind.namespace() == ns)
324 .find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
328 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
329 pub enum Visibility {
330 /// Visible everywhere (including in other crates).
332 /// Visible only in the given crate-local module.
334 /// Not visible anywhere in the local crate. This is the visibility of private external items.
338 pub trait DefIdTree: Copy {
339 fn parent(self, id: DefId) -> Option<DefId>;
341 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
342 if descendant.krate != ancestor.krate {
346 while descendant != ancestor {
347 match self.parent(descendant) {
348 Some(parent) => descendant = parent,
349 None => return false,
356 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
357 fn parent(self, id: DefId) -> Option<DefId> {
358 self.def_key(id).parent.map(|index| DefId { index, ..id })
363 pub fn from_hir(visibility: &hir::Visibility<'_>, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
364 match visibility.node {
365 hir::VisibilityKind::Public => Visibility::Public,
366 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
367 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
368 // If there is no resolution, `resolve` will have already reported an error, so
369 // assume that the visibility is public to avoid reporting more privacy errors.
370 Res::Err => Visibility::Public,
371 def => Visibility::Restricted(def.def_id()),
373 hir::VisibilityKind::Inherited => {
374 Visibility::Restricted(tcx.parent_module(id).to_def_id())
379 /// Returns `true` if an item with this visibility is accessible from the given block.
380 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
381 let restriction = match self {
382 // Public items are visible everywhere.
383 Visibility::Public => return true,
384 // Private items from other crates are visible nowhere.
385 Visibility::Invisible => return false,
386 // Restricted items are visible in an arbitrary local module.
387 Visibility::Restricted(other) if other.krate != module.krate => return false,
388 Visibility::Restricted(module) => module,
391 tree.is_descendant_of(module, restriction)
394 /// Returns `true` if this visibility is at least as accessible as the given visibility
395 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
396 let vis_restriction = match vis {
397 Visibility::Public => return self == Visibility::Public,
398 Visibility::Invisible => return true,
399 Visibility::Restricted(module) => module,
402 self.is_accessible_from(vis_restriction, tree)
405 // Returns `true` if this item is visible anywhere in the local crate.
406 pub fn is_visible_locally(self) -> bool {
408 Visibility::Public => true,
409 Visibility::Restricted(def_id) => def_id.is_local(),
410 Visibility::Invisible => false,
415 #[derive(Copy, Clone, PartialEq, RustcDecodable, RustcEncodable, HashStable)]
417 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
418 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
419 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
420 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
423 /// The crate variances map is computed during typeck and contains the
424 /// variance of every item in the local crate. You should not use it
425 /// directly, because to do so will make your pass dependent on the
426 /// HIR of every item in the local crate. Instead, use
427 /// `tcx.variances_of()` to get the variance for a *particular*
429 #[derive(HashStable)]
430 pub struct CrateVariancesMap<'tcx> {
431 /// For each item with generics, maps to a vector of the variance
432 /// of its generics. If an item has no generics, it will have no
434 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
438 /// `a.xform(b)` combines the variance of a context with the
439 /// variance of a type with the following meaning. If we are in a
440 /// context with variance `a`, and we encounter a type argument in
441 /// a position with variance `b`, then `a.xform(b)` is the new
442 /// variance with which the argument appears.
448 /// Here, the "ambient" variance starts as covariant. `*mut T` is
449 /// invariant with respect to `T`, so the variance in which the
450 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
451 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
452 /// respect to its type argument `T`, and hence the variance of
453 /// the `i32` here is `Invariant.xform(Covariant)`, which results
454 /// (again) in `Invariant`.
458 /// fn(*const Vec<i32>, *mut Vec<i32)
460 /// The ambient variance is covariant. A `fn` type is
461 /// contravariant with respect to its parameters, so the variance
462 /// within which both pointer types appear is
463 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
464 /// T` is covariant with respect to `T`, so the variance within
465 /// which the first `Vec<i32>` appears is
466 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
467 /// is true for its `i32` argument. In the `*mut T` case, the
468 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
469 /// and hence the outermost type is `Invariant` with respect to
470 /// `Vec<i32>` (and its `i32` argument).
472 /// Source: Figure 1 of "Taming the Wildcards:
473 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
474 pub fn xform(self, v: ty::Variance) -> ty::Variance {
476 // Figure 1, column 1.
477 (ty::Covariant, ty::Covariant) => ty::Covariant,
478 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
479 (ty::Covariant, ty::Invariant) => ty::Invariant,
480 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
482 // Figure 1, column 2.
483 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
484 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
485 (ty::Contravariant, ty::Invariant) => ty::Invariant,
486 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
488 // Figure 1, column 3.
489 (ty::Invariant, _) => ty::Invariant,
491 // Figure 1, column 4.
492 (ty::Bivariant, _) => ty::Bivariant,
497 // Contains information needed to resolve types and (in the future) look up
498 // the types of AST nodes.
499 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
500 pub struct CReaderCacheKey {
506 /// Flags that we track on types. These flags are propagated upwards
507 /// through the type during type construction, so that we can quickly check
508 /// whether the type has various kinds of types in it without recursing
509 /// over the type itself.
510 pub struct TypeFlags: u32 {
511 // Does this have parameters? Used to determine whether substitution is
513 /// Does this have [Param]?
514 const HAS_TY_PARAM = 1 << 0;
515 /// Does this have [ReEarlyBound]?
516 const HAS_RE_PARAM = 1 << 1;
517 /// Does this have [ConstKind::Param]?
518 const HAS_CT_PARAM = 1 << 2;
520 const NEEDS_SUBST = TypeFlags::HAS_TY_PARAM.bits
521 | TypeFlags::HAS_RE_PARAM.bits
522 | TypeFlags::HAS_CT_PARAM.bits;
524 /// Does this have [Infer]?
525 const HAS_TY_INFER = 1 << 3;
526 /// Does this have [ReVar]?
527 const HAS_RE_INFER = 1 << 4;
528 /// Does this have [ConstKind::Infer]?
529 const HAS_CT_INFER = 1 << 5;
531 /// Does this have inference variables? Used to determine whether
532 /// inference is required.
533 const NEEDS_INFER = TypeFlags::HAS_TY_INFER.bits
534 | TypeFlags::HAS_RE_INFER.bits
535 | TypeFlags::HAS_CT_INFER.bits;
537 /// Does this have [Placeholder]?
538 const HAS_TY_PLACEHOLDER = 1 << 6;
539 /// Does this have [RePlaceholder]?
540 const HAS_RE_PLACEHOLDER = 1 << 7;
541 /// Does this have [ConstKind::Placeholder]?
542 const HAS_CT_PLACEHOLDER = 1 << 8;
544 /// `true` if there are "names" of regions and so forth
545 /// that are local to a particular fn/inferctxt
546 const HAS_FREE_LOCAL_REGIONS = 1 << 9;
548 /// `true` if there are "names" of types and regions and so forth
549 /// that are local to a particular fn
550 const HAS_FREE_LOCAL_NAMES = TypeFlags::HAS_TY_PARAM.bits
551 | TypeFlags::HAS_CT_PARAM.bits
552 | TypeFlags::HAS_TY_INFER.bits
553 | TypeFlags::HAS_CT_INFER.bits
554 | TypeFlags::HAS_TY_PLACEHOLDER.bits
555 | TypeFlags::HAS_CT_PLACEHOLDER.bits
556 | TypeFlags::HAS_FREE_LOCAL_REGIONS.bits;
558 /// Does this have [Projection]?
559 const HAS_TY_PROJECTION = 1 << 10;
560 /// Does this have [Opaque]?
561 const HAS_TY_OPAQUE = 1 << 11;
562 /// Does this have [ConstKind::Unevaluated]?
563 const HAS_CT_PROJECTION = 1 << 12;
565 /// Could this type be normalized further?
566 const HAS_PROJECTION = TypeFlags::HAS_TY_PROJECTION.bits
567 | TypeFlags::HAS_TY_OPAQUE.bits
568 | TypeFlags::HAS_CT_PROJECTION.bits;
570 /// Is an error type/const reachable?
571 const HAS_ERROR = 1 << 13;
573 /// Does this have any region that "appears free" in the type?
574 /// Basically anything but [ReLateBound] and [ReErased].
575 const HAS_FREE_REGIONS = 1 << 14;
577 /// Does this have any [ReLateBound] regions? Used to check
578 /// if a global bound is safe to evaluate.
579 const HAS_RE_LATE_BOUND = 1 << 15;
581 /// Does this have any [ReErased] regions?
582 const HAS_RE_ERASED = 1 << 16;
584 /// Does this value have parameters/placeholders/inference variables which could be
585 /// replaced later, in a way that would change the results of `impl` specialization?
586 const STILL_FURTHER_SPECIALIZABLE = 1 << 17;
590 #[allow(rustc::usage_of_ty_tykind)]
591 pub struct TyS<'tcx> {
592 pub kind: TyKind<'tcx>,
593 pub flags: TypeFlags,
595 /// This is a kind of confusing thing: it stores the smallest
598 /// (a) the binder itself captures nothing but
599 /// (b) all the late-bound things within the type are captured
600 /// by some sub-binder.
602 /// So, for a type without any late-bound things, like `u32`, this
603 /// will be *innermost*, because that is the innermost binder that
604 /// captures nothing. But for a type `&'D u32`, where `'D` is a
605 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
606 /// -- the binder itself does not capture `D`, but `D` is captured
607 /// by an inner binder.
609 /// We call this concept an "exclusive" binder `D` because all
610 /// De Bruijn indices within the type are contained within `0..D`
612 outer_exclusive_binder: ty::DebruijnIndex,
615 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
616 #[cfg(target_arch = "x86_64")]
617 static_assert_size!(TyS<'_>, 32);
619 impl<'tcx> Ord for TyS<'tcx> {
620 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
621 self.kind.cmp(&other.kind)
625 impl<'tcx> PartialOrd for TyS<'tcx> {
626 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
627 Some(self.kind.cmp(&other.kind))
631 impl<'tcx> PartialEq for TyS<'tcx> {
633 fn eq(&self, other: &TyS<'tcx>) -> bool {
637 impl<'tcx> Eq for TyS<'tcx> {}
639 impl<'tcx> Hash for TyS<'tcx> {
640 fn hash<H: Hasher>(&self, s: &mut H) {
641 (self as *const TyS<'_>).hash(s)
645 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
646 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
650 // The other fields just provide fast access to information that is
651 // also contained in `kind`, so no need to hash them.
654 outer_exclusive_binder: _,
657 kind.hash_stable(hcx, hasher);
661 #[rustc_diagnostic_item = "Ty"]
662 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
664 impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {}
665 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {}
666 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
668 pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
670 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
671 pub struct UpvarPath {
672 pub hir_id: hir::HirId,
675 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
676 /// the original var ID (that is, the root variable that is referenced
677 /// by the upvar) and the ID of the closure expression.
678 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
680 pub var_path: UpvarPath,
681 pub closure_expr_id: LocalDefId,
684 #[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
685 pub enum BorrowKind {
686 /// Data must be immutable and is aliasable.
689 /// Data must be immutable but not aliasable. This kind of borrow
690 /// cannot currently be expressed by the user and is used only in
691 /// implicit closure bindings. It is needed when the closure
692 /// is borrowing or mutating a mutable referent, e.g.:
694 /// let x: &mut isize = ...;
695 /// let y = || *x += 5;
697 /// If we were to try to translate this closure into a more explicit
698 /// form, we'd encounter an error with the code as written:
700 /// struct Env { x: & &mut isize }
701 /// let x: &mut isize = ...;
702 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
703 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
705 /// This is then illegal because you cannot mutate a `&mut` found
706 /// in an aliasable location. To solve, you'd have to translate with
707 /// an `&mut` borrow:
709 /// struct Env { x: & &mut isize }
710 /// let x: &mut isize = ...;
711 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
712 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
714 /// Now the assignment to `**env.x` is legal, but creating a
715 /// mutable pointer to `x` is not because `x` is not mutable. We
716 /// could fix this by declaring `x` as `let mut x`. This is ok in
717 /// user code, if awkward, but extra weird for closures, since the
718 /// borrow is hidden.
720 /// So we introduce a "unique imm" borrow -- the referent is
721 /// immutable, but not aliasable. This solves the problem. For
722 /// simplicity, we don't give users the way to express this
723 /// borrow, it's just used when translating closures.
726 /// Data is mutable and not aliasable.
730 /// Information describing the capture of an upvar. This is computed
731 /// during `typeck`, specifically by `regionck`.
732 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
733 pub enum UpvarCapture<'tcx> {
734 /// Upvar is captured by value. This is always true when the
735 /// closure is labeled `move`, but can also be true in other cases
736 /// depending on inference.
739 /// Upvar is captured by reference.
740 ByRef(UpvarBorrow<'tcx>),
743 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
744 pub struct UpvarBorrow<'tcx> {
745 /// The kind of borrow: by-ref upvars have access to shared
746 /// immutable borrows, which are not part of the normal language
748 pub kind: BorrowKind,
750 /// Region of the resulting reference.
751 pub region: ty::Region<'tcx>,
754 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
755 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
757 #[derive(Clone, Copy, PartialEq, Eq)]
758 pub enum IntVarValue {
760 UintType(ast::UintTy),
763 #[derive(Clone, Copy, PartialEq, Eq)]
764 pub struct FloatVarValue(pub ast::FloatTy);
766 impl ty::EarlyBoundRegion {
767 pub fn to_bound_region(&self) -> ty::BoundRegion {
768 ty::BoundRegion::BrNamed(self.def_id, self.name)
771 /// Does this early bound region have a name? Early bound regions normally
772 /// always have names except when using anonymous lifetimes (`'_`).
773 pub fn has_name(&self) -> bool {
774 self.name != kw::UnderscoreLifetime
778 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
779 pub enum GenericParamDefKind {
783 object_lifetime_default: ObjectLifetimeDefault,
784 synthetic: Option<hir::SyntheticTyParamKind>,
789 impl GenericParamDefKind {
790 pub fn descr(&self) -> &'static str {
792 GenericParamDefKind::Lifetime => "lifetime",
793 GenericParamDefKind::Type { .. } => "type",
794 GenericParamDefKind::Const => "constant",
799 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
800 pub struct GenericParamDef {
805 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
806 /// on generic parameter `'a`/`T`, asserts data behind the parameter
807 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
808 pub pure_wrt_drop: bool,
810 pub kind: GenericParamDefKind,
813 impl GenericParamDef {
814 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
815 if let GenericParamDefKind::Lifetime = self.kind {
816 ty::EarlyBoundRegion { def_id: self.def_id, index: self.index, name: self.name }
818 bug!("cannot convert a non-lifetime parameter def to an early bound region")
822 pub fn to_bound_region(&self) -> ty::BoundRegion {
823 if let GenericParamDefKind::Lifetime = self.kind {
824 self.to_early_bound_region_data().to_bound_region()
826 bug!("cannot convert a non-lifetime parameter def to an early bound region")
832 pub struct GenericParamCount {
833 pub lifetimes: usize,
838 /// Information about the formal type/lifetime parameters associated
839 /// with an item or method. Analogous to `hir::Generics`.
841 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
842 /// `Self` (optionally), `Lifetime` params..., `Type` params...
843 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
844 pub struct Generics {
845 pub parent: Option<DefId>,
846 pub parent_count: usize,
847 pub params: Vec<GenericParamDef>,
849 /// Reverse map to the `index` field of each `GenericParamDef`.
850 #[stable_hasher(ignore)]
851 pub param_def_id_to_index: FxHashMap<DefId, u32>,
854 pub has_late_bound_regions: Option<Span>,
857 impl<'tcx> Generics {
858 pub fn count(&self) -> usize {
859 self.parent_count + self.params.len()
862 pub fn own_counts(&self) -> GenericParamCount {
863 // We could cache this as a property of `GenericParamCount`, but
864 // the aim is to refactor this away entirely eventually and the
865 // presence of this method will be a constant reminder.
866 let mut own_counts: GenericParamCount = Default::default();
868 for param in &self.params {
870 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
871 GenericParamDefKind::Type { .. } => own_counts.types += 1,
872 GenericParamDefKind::Const => own_counts.consts += 1,
879 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
880 if self.own_requires_monomorphization() {
884 if let Some(parent_def_id) = self.parent {
885 let parent = tcx.generics_of(parent_def_id);
886 parent.requires_monomorphization(tcx)
892 pub fn own_requires_monomorphization(&self) -> bool {
893 for param in &self.params {
895 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
896 GenericParamDefKind::Lifetime => {}
902 pub fn param_at(&'tcx self, param_index: usize, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
903 if let Some(index) = param_index.checked_sub(self.parent_count) {
906 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
907 .param_at(param_index, tcx)
913 param: &EarlyBoundRegion,
915 ) -> &'tcx GenericParamDef {
916 let param = self.param_at(param.index as usize, tcx);
918 GenericParamDefKind::Lifetime => param,
919 _ => bug!("expected lifetime parameter, but found another generic parameter"),
923 /// Returns the `GenericParamDef` associated with this `ParamTy`.
924 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
925 let param = self.param_at(param.index as usize, tcx);
927 GenericParamDefKind::Type { .. } => param,
928 _ => bug!("expected type parameter, but found another generic parameter"),
932 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
933 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
934 let param = self.param_at(param.index as usize, tcx);
936 GenericParamDefKind::Const => param,
937 _ => bug!("expected const parameter, but found another generic parameter"),
942 /// Bounds on generics.
943 #[derive(Copy, Clone, Default, Debug, RustcEncodable, RustcDecodable, HashStable)]
944 pub struct GenericPredicates<'tcx> {
945 pub parent: Option<DefId>,
946 pub predicates: &'tcx [(Predicate<'tcx>, Span)],
949 impl<'tcx> GenericPredicates<'tcx> {
953 substs: SubstsRef<'tcx>,
954 ) -> InstantiatedPredicates<'tcx> {
955 let mut instantiated = InstantiatedPredicates::empty();
956 self.instantiate_into(tcx, &mut instantiated, substs);
960 pub fn instantiate_own(
963 substs: SubstsRef<'tcx>,
964 ) -> InstantiatedPredicates<'tcx> {
965 InstantiatedPredicates {
966 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
967 spans: self.predicates.iter().map(|(_, sp)| *sp).collect(),
974 instantiated: &mut InstantiatedPredicates<'tcx>,
975 substs: SubstsRef<'tcx>,
977 if let Some(def_id) = self.parent {
978 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
980 instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)));
981 instantiated.spans.extend(self.predicates.iter().map(|(_, sp)| *sp));
984 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
985 let mut instantiated = InstantiatedPredicates::empty();
986 self.instantiate_identity_into(tcx, &mut instantiated);
990 fn instantiate_identity_into(
993 instantiated: &mut InstantiatedPredicates<'tcx>,
995 if let Some(def_id) = self.parent {
996 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
998 instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p));
999 instantiated.spans.extend(self.predicates.iter().map(|(_, s)| s));
1002 pub fn instantiate_supertrait(
1005 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1006 ) -> InstantiatedPredicates<'tcx> {
1007 assert_eq!(self.parent, None);
1008 InstantiatedPredicates {
1012 .map(|(pred, _)| pred.subst_supertrait(tcx, poly_trait_ref))
1014 spans: self.predicates.iter().map(|(_, sp)| *sp).collect(),
1019 pub type Predicate<'tcx> = PredicateKind<'tcx>;
1021 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1022 #[derive(HashStable, TypeFoldable)]
1023 pub enum PredicateKind<'tcx> {
1024 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1025 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1026 /// would be the type parameters.
1028 /// A trait predicate will have `Constness::Const` if it originates
1029 /// from a bound on a `const fn` without the `?const` opt-out (e.g.,
1030 /// `const fn foobar<Foo: Bar>() {}`).
1031 Trait(PolyTraitPredicate<'tcx>, Constness),
1034 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1037 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1039 /// `where <T as TraitRef>::Name == X`, approximately.
1040 /// See the `ProjectionPredicate` struct for details.
1041 Projection(PolyProjectionPredicate<'tcx>),
1043 /// No syntax: `T` well-formed.
1044 WellFormed(Ty<'tcx>),
1046 /// Trait must be object-safe.
1049 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1050 /// for some substitutions `...` and `T` being a closure type.
1051 /// Satisfied (or refuted) once we know the closure's kind.
1052 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
1055 Subtype(PolySubtypePredicate<'tcx>),
1057 /// Constant initializer must evaluate successfully.
1058 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1060 /// Constants must be equal. The first component is the const that is expected.
1061 ConstEquate(&'tcx Const<'tcx>, &'tcx Const<'tcx>),
1064 /// The crate outlives map is computed during typeck and contains the
1065 /// outlives of every item in the local crate. You should not use it
1066 /// directly, because to do so will make your pass dependent on the
1067 /// HIR of every item in the local crate. Instead, use
1068 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1070 #[derive(HashStable)]
1071 pub struct CratePredicatesMap<'tcx> {
1072 /// For each struct with outlive bounds, maps to a vector of the
1073 /// predicate of its outlive bounds. If an item has no outlives
1074 /// bounds, it will have no entry.
1075 pub predicates: FxHashMap<DefId, &'tcx [(ty::Predicate<'tcx>, Span)]>,
1078 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1079 fn as_ref(&self) -> &Predicate<'tcx> {
1084 impl<'tcx> PredicateKind<'tcx> {
1085 /// Performs a substitution suitable for going from a
1086 /// poly-trait-ref to supertraits that must hold if that
1087 /// poly-trait-ref holds. This is slightly different from a normal
1088 /// substitution in terms of what happens with bound regions. See
1089 /// lengthy comment below for details.
1090 pub fn subst_supertrait(
1093 trait_ref: &ty::PolyTraitRef<'tcx>,
1094 ) -> ty::Predicate<'tcx> {
1095 // The interaction between HRTB and supertraits is not entirely
1096 // obvious. Let me walk you (and myself) through an example.
1098 // Let's start with an easy case. Consider two traits:
1100 // trait Foo<'a>: Bar<'a,'a> { }
1101 // trait Bar<'b,'c> { }
1103 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1104 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1105 // knew that `Foo<'x>` (for any 'x) then we also know that
1106 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1107 // normal substitution.
1109 // In terms of why this is sound, the idea is that whenever there
1110 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1111 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1112 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1115 // Another example to be careful of is this:
1117 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1118 // trait Bar1<'b,'c> { }
1120 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1121 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1122 // reason is similar to the previous example: any impl of
1123 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1124 // basically we would want to collapse the bound lifetimes from
1125 // the input (`trait_ref`) and the supertraits.
1127 // To achieve this in practice is fairly straightforward. Let's
1128 // consider the more complicated scenario:
1130 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1131 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1132 // where both `'x` and `'b` would have a DB index of 1.
1133 // The substitution from the input trait-ref is therefore going to be
1134 // `'a => 'x` (where `'x` has a DB index of 1).
1135 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1136 // early-bound parameter and `'b' is a late-bound parameter with a
1138 // - If we replace `'a` with `'x` from the input, it too will have
1139 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1140 // just as we wanted.
1142 // There is only one catch. If we just apply the substitution `'a
1143 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1144 // adjust the DB index because we substituting into a binder (it
1145 // tries to be so smart...) resulting in `for<'x> for<'b>
1146 // Bar1<'x,'b>` (we have no syntax for this, so use your
1147 // imagination). Basically the 'x will have DB index of 2 and 'b
1148 // will have DB index of 1. Not quite what we want. So we apply
1149 // the substitution to the *contents* of the trait reference,
1150 // rather than the trait reference itself (put another way, the
1151 // substitution code expects equal binding levels in the values
1152 // from the substitution and the value being substituted into, and
1153 // this trick achieves that).
1155 let substs = &trait_ref.skip_binder().substs;
1157 PredicateKind::Trait(ref binder, constness) => {
1158 PredicateKind::Trait(binder.map_bound(|data| data.subst(tcx, substs)), constness)
1160 PredicateKind::Subtype(ref binder) => {
1161 PredicateKind::Subtype(binder.map_bound(|data| data.subst(tcx, substs)))
1163 PredicateKind::RegionOutlives(ref binder) => {
1164 PredicateKind::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs)))
1166 PredicateKind::TypeOutlives(ref binder) => {
1167 PredicateKind::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs)))
1169 PredicateKind::Projection(ref binder) => {
1170 PredicateKind::Projection(binder.map_bound(|data| data.subst(tcx, substs)))
1172 PredicateKind::WellFormed(data) => PredicateKind::WellFormed(data.subst(tcx, substs)),
1173 PredicateKind::ObjectSafe(trait_def_id) => PredicateKind::ObjectSafe(trait_def_id),
1174 PredicateKind::ClosureKind(closure_def_id, closure_substs, kind) => {
1175 PredicateKind::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind)
1177 PredicateKind::ConstEvaluatable(def_id, const_substs) => {
1178 PredicateKind::ConstEvaluatable(def_id, const_substs.subst(tcx, substs))
1180 PredicateKind::ConstEquate(c1, c2) => {
1181 PredicateKind::ConstEquate(c1.subst(tcx, substs), c2.subst(tcx, substs))
1187 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1188 #[derive(HashStable, TypeFoldable)]
1189 pub struct TraitPredicate<'tcx> {
1190 pub trait_ref: TraitRef<'tcx>,
1193 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1195 impl<'tcx> TraitPredicate<'tcx> {
1196 pub fn def_id(&self) -> DefId {
1197 self.trait_ref.def_id
1200 pub fn self_ty(&self) -> Ty<'tcx> {
1201 self.trait_ref.self_ty()
1205 impl<'tcx> PolyTraitPredicate<'tcx> {
1206 pub fn def_id(&self) -> DefId {
1207 // Ok to skip binder since trait `DefId` does not care about regions.
1208 self.skip_binder().def_id()
1212 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1213 #[derive(HashStable, TypeFoldable)]
1214 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1215 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1216 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1217 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1218 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1219 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1221 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1222 #[derive(HashStable, TypeFoldable)]
1223 pub struct SubtypePredicate<'tcx> {
1224 pub a_is_expected: bool,
1228 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1230 /// This kind of predicate has no *direct* correspondent in the
1231 /// syntax, but it roughly corresponds to the syntactic forms:
1233 /// 1. `T: TraitRef<..., Item = Type>`
1234 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1236 /// In particular, form #1 is "desugared" to the combination of a
1237 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1238 /// predicates. Form #2 is a broader form in that it also permits
1239 /// equality between arbitrary types. Processing an instance of
1240 /// Form #2 eventually yields one of these `ProjectionPredicate`
1241 /// instances to normalize the LHS.
1242 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1243 #[derive(HashStable, TypeFoldable)]
1244 pub struct ProjectionPredicate<'tcx> {
1245 pub projection_ty: ProjectionTy<'tcx>,
1249 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1251 impl<'tcx> PolyProjectionPredicate<'tcx> {
1252 /// Returns the `DefId` of the associated item being projected.
1253 pub fn item_def_id(&self) -> DefId {
1254 self.skip_binder().projection_ty.item_def_id
1258 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
1259 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1260 // `self.0.trait_ref` is permitted to have escaping regions.
1261 // This is because here `self` has a `Binder` and so does our
1262 // return value, so we are preserving the number of binding
1264 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1267 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1268 self.map_bound(|predicate| predicate.ty)
1271 /// The `DefId` of the `TraitItem` for the associated type.
1273 /// Note that this is not the `DefId` of the `TraitRef` containing this
1274 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1275 pub fn projection_def_id(&self) -> DefId {
1276 // Ok to skip binder since trait `DefId` does not care about regions.
1277 self.skip_binder().projection_ty.item_def_id
1281 pub trait ToPolyTraitRef<'tcx> {
1282 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1285 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1286 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1287 ty::Binder::dummy(*self)
1291 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1292 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1293 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1297 pub trait ToPredicate<'tcx> {
1298 fn to_predicate(&self) -> Predicate<'tcx>;
1301 impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<TraitRef<'tcx>> {
1302 fn to_predicate(&self) -> Predicate<'tcx> {
1303 ty::PredicateKind::Trait(
1304 ty::Binder::dummy(ty::TraitPredicate { trait_ref: self.value }),
1310 impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<&TraitRef<'tcx>> {
1311 fn to_predicate(&self) -> Predicate<'tcx> {
1312 ty::PredicateKind::Trait(
1313 ty::Binder::dummy(ty::TraitPredicate { trait_ref: *self.value }),
1319 impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<PolyTraitRef<'tcx>> {
1320 fn to_predicate(&self) -> Predicate<'tcx> {
1321 ty::PredicateKind::Trait(self.value.to_poly_trait_predicate(), self.constness)
1325 impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<&PolyTraitRef<'tcx>> {
1326 fn to_predicate(&self) -> Predicate<'tcx> {
1327 ty::PredicateKind::Trait(self.value.to_poly_trait_predicate(), self.constness)
1331 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1332 fn to_predicate(&self) -> Predicate<'tcx> {
1333 PredicateKind::RegionOutlives(*self)
1337 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1338 fn to_predicate(&self) -> Predicate<'tcx> {
1339 PredicateKind::TypeOutlives(*self)
1343 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1344 fn to_predicate(&self) -> Predicate<'tcx> {
1345 PredicateKind::Projection(*self)
1349 impl<'tcx> PredicateKind<'tcx> {
1350 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1352 PredicateKind::Trait(ref t, _) => Some(t.to_poly_trait_ref()),
1353 PredicateKind::Projection(..)
1354 | PredicateKind::Subtype(..)
1355 | PredicateKind::RegionOutlives(..)
1356 | PredicateKind::WellFormed(..)
1357 | PredicateKind::ObjectSafe(..)
1358 | PredicateKind::ClosureKind(..)
1359 | PredicateKind::TypeOutlives(..)
1360 | PredicateKind::ConstEvaluatable(..)
1361 | PredicateKind::ConstEquate(..) => None,
1365 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1367 PredicateKind::TypeOutlives(data) => Some(data),
1368 PredicateKind::Trait(..)
1369 | PredicateKind::Projection(..)
1370 | PredicateKind::Subtype(..)
1371 | PredicateKind::RegionOutlives(..)
1372 | PredicateKind::WellFormed(..)
1373 | PredicateKind::ObjectSafe(..)
1374 | PredicateKind::ClosureKind(..)
1375 | PredicateKind::ConstEvaluatable(..)
1376 | PredicateKind::ConstEquate(..) => None,
1381 /// Represents the bounds declared on a particular set of type
1382 /// parameters. Should eventually be generalized into a flag list of
1383 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1384 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1385 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1386 /// the `GenericPredicates` are expressed in terms of the bound type
1387 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1388 /// represented a set of bounds for some particular instantiation,
1389 /// meaning that the generic parameters have been substituted with
1394 /// struct Foo<T, U: Bar<T>> { ... }
1396 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1397 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1398 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1399 /// [usize:Bar<isize>]]`.
1400 #[derive(Clone, Debug, TypeFoldable)]
1401 pub struct InstantiatedPredicates<'tcx> {
1402 pub predicates: Vec<Predicate<'tcx>>,
1403 pub spans: Vec<Span>,
1406 impl<'tcx> InstantiatedPredicates<'tcx> {
1407 pub fn empty() -> InstantiatedPredicates<'tcx> {
1408 InstantiatedPredicates { predicates: vec![], spans: vec![] }
1411 pub fn is_empty(&self) -> bool {
1412 self.predicates.is_empty()
1416 rustc_index::newtype_index! {
1417 /// "Universes" are used during type- and trait-checking in the
1418 /// presence of `for<..>` binders to control what sets of names are
1419 /// visible. Universes are arranged into a tree: the root universe
1420 /// contains names that are always visible. Each child then adds a new
1421 /// set of names that are visible, in addition to those of its parent.
1422 /// We say that the child universe "extends" the parent universe with
1425 /// To make this more concrete, consider this program:
1429 /// fn bar<T>(x: T) {
1430 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1434 /// The struct name `Foo` is in the root universe U0. But the type
1435 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1436 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1437 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1438 /// region `'a` is in a universe U2 that extends U1, because we can
1439 /// name it inside the fn type but not outside.
1441 /// Universes are used to do type- and trait-checking around these
1442 /// "forall" binders (also called **universal quantification**). The
1443 /// idea is that when, in the body of `bar`, we refer to `T` as a
1444 /// type, we aren't referring to any type in particular, but rather a
1445 /// kind of "fresh" type that is distinct from all other types we have
1446 /// actually declared. This is called a **placeholder** type, and we
1447 /// use universes to talk about this. In other words, a type name in
1448 /// universe 0 always corresponds to some "ground" type that the user
1449 /// declared, but a type name in a non-zero universe is a placeholder
1450 /// type -- an idealized representative of "types in general" that we
1451 /// use for checking generic functions.
1452 pub struct UniverseIndex {
1454 DEBUG_FORMAT = "U{}",
1458 impl UniverseIndex {
1459 pub const ROOT: UniverseIndex = UniverseIndex::from_u32(0);
1461 /// Returns the "next" universe index in order -- this new index
1462 /// is considered to extend all previous universes. This
1463 /// corresponds to entering a `forall` quantifier. So, for
1464 /// example, suppose we have this type in universe `U`:
1467 /// for<'a> fn(&'a u32)
1470 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1471 /// new universe that extends `U` -- in this new universe, we can
1472 /// name the region `'a`, but that region was not nameable from
1473 /// `U` because it was not in scope there.
1474 pub fn next_universe(self) -> UniverseIndex {
1475 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1478 /// Returns `true` if `self` can name a name from `other` -- in other words,
1479 /// if the set of names in `self` is a superset of those in
1480 /// `other` (`self >= other`).
1481 pub fn can_name(self, other: UniverseIndex) -> bool {
1482 self.private >= other.private
1485 /// Returns `true` if `self` cannot name some names from `other` -- in other
1486 /// words, if the set of names in `self` is a strict subset of
1487 /// those in `other` (`self < other`).
1488 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1489 self.private < other.private
1493 /// The "placeholder index" fully defines a placeholder region.
1494 /// Placeholder regions are identified by both a **universe** as well
1495 /// as a "bound-region" within that universe. The `bound_region` is
1496 /// basically a name -- distinct bound regions within the same
1497 /// universe are just two regions with an unknown relationship to one
1499 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1500 pub struct Placeholder<T> {
1501 pub universe: UniverseIndex,
1505 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1507 T: HashStable<StableHashingContext<'a>>,
1509 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1510 self.universe.hash_stable(hcx, hasher);
1511 self.name.hash_stable(hcx, hasher);
1515 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1517 pub type PlaceholderType = Placeholder<BoundVar>;
1519 pub type PlaceholderConst = Placeholder<BoundVar>;
1521 /// When type checking, we use the `ParamEnv` to track
1522 /// details about the set of where-clauses that are in scope at this
1523 /// particular point.
1524 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TypeFoldable)]
1525 pub struct ParamEnv<'tcx> {
1526 /// `Obligation`s that the caller must satisfy. This is basically
1527 /// the set of bounds on the in-scope type parameters, translated
1528 /// into `Obligation`s, and elaborated and normalized.
1529 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1531 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1532 /// want `Reveal::All` -- note that this is always paired with an
1533 /// empty environment. To get that, use `ParamEnv::reveal()`.
1534 pub reveal: traits::Reveal,
1536 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1537 /// register that `def_id` (useful for transitioning to the chalk trait
1539 pub def_id: Option<DefId>,
1542 impl<'tcx> ParamEnv<'tcx> {
1543 /// Construct a trait environment suitable for contexts where
1544 /// there are no where-clauses in scope. Hidden types (like `impl
1545 /// Trait`) are left hidden, so this is suitable for ordinary
1548 pub fn empty() -> Self {
1549 Self::new(List::empty(), Reveal::UserFacing, None)
1552 /// Construct a trait environment with no where-clauses in scope
1553 /// where the values of all `impl Trait` and other hidden types
1554 /// are revealed. This is suitable for monomorphized, post-typeck
1555 /// environments like codegen or doing optimizations.
1557 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1558 /// or invoke `param_env.with_reveal_all()`.
1560 pub fn reveal_all() -> Self {
1561 Self::new(List::empty(), Reveal::All, None)
1564 /// Construct a trait environment with the given set of predicates.
1567 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1569 def_id: Option<DefId>,
1571 ty::ParamEnv { caller_bounds, reveal, def_id }
1574 /// Returns a new parameter environment with the same clauses, but
1575 /// which "reveals" the true results of projections in all cases
1576 /// (even for associated types that are specializable). This is
1577 /// the desired behavior during codegen and certain other special
1578 /// contexts; normally though we want to use `Reveal::UserFacing`,
1579 /// which is the default.
1580 pub fn with_reveal_all(self) -> Self {
1581 ty::ParamEnv { reveal: Reveal::All, ..self }
1584 /// Returns this same environment but with no caller bounds.
1585 pub fn without_caller_bounds(self) -> Self {
1586 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1589 /// Creates a suitable environment in which to perform trait
1590 /// queries on the given value. When type-checking, this is simply
1591 /// the pair of the environment plus value. But when reveal is set to
1592 /// All, then if `value` does not reference any type parameters, we will
1593 /// pair it with the empty environment. This improves caching and is generally
1596 /// N.B., we preserve the environment when type-checking because it
1597 /// is possible for the user to have wacky where-clauses like
1598 /// `where Box<u32>: Copy`, which are clearly never
1599 /// satisfiable. We generally want to behave as if they were true,
1600 /// although the surrounding function is never reachable.
1601 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1603 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1606 if value.is_global() {
1607 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1609 ParamEnvAnd { param_env: self, value }
1616 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1617 pub struct ConstnessAnd<T> {
1618 pub constness: Constness,
1622 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate()` to ensure that
1623 // the constness of trait bounds is being propagated correctly.
1624 pub trait WithConstness: Sized {
1626 fn with_constness(self, constness: Constness) -> ConstnessAnd<Self> {
1627 ConstnessAnd { constness, value: self }
1631 fn with_const(self) -> ConstnessAnd<Self> {
1632 self.with_constness(Constness::Const)
1636 fn without_const(self) -> ConstnessAnd<Self> {
1637 self.with_constness(Constness::NotConst)
1641 impl<T> WithConstness for T {}
1643 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1644 pub struct ParamEnvAnd<'tcx, T> {
1645 pub param_env: ParamEnv<'tcx>,
1649 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1650 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1651 (self.param_env, self.value)
1655 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1657 T: HashStable<StableHashingContext<'a>>,
1659 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1660 let ParamEnvAnd { ref param_env, ref value } = *self;
1662 param_env.hash_stable(hcx, hasher);
1663 value.hash_stable(hcx, hasher);
1667 #[derive(Copy, Clone, Debug, HashStable)]
1668 pub struct Destructor {
1669 /// The `DefId` of the destructor method
1674 #[derive(HashStable)]
1675 pub struct AdtFlags: u32 {
1676 const NO_ADT_FLAGS = 0;
1677 /// Indicates whether the ADT is an enum.
1678 const IS_ENUM = 1 << 0;
1679 /// Indicates whether the ADT is a union.
1680 const IS_UNION = 1 << 1;
1681 /// Indicates whether the ADT is a struct.
1682 const IS_STRUCT = 1 << 2;
1683 /// Indicates whether the ADT is a struct and has a constructor.
1684 const HAS_CTOR = 1 << 3;
1685 /// Indicates whether the type is `PhantomData`.
1686 const IS_PHANTOM_DATA = 1 << 4;
1687 /// Indicates whether the type has a `#[fundamental]` attribute.
1688 const IS_FUNDAMENTAL = 1 << 5;
1689 /// Indicates whether the type is `Box`.
1690 const IS_BOX = 1 << 6;
1691 /// Indicates whether the type is `ManuallyDrop`.
1692 const IS_MANUALLY_DROP = 1 << 7;
1693 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1694 /// (i.e., this flag is never set unless this ADT is an enum).
1695 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 8;
1700 #[derive(HashStable)]
1701 pub struct VariantFlags: u32 {
1702 const NO_VARIANT_FLAGS = 0;
1703 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1704 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1708 /// Definition of a variant -- a struct's fields or a enum variant.
1709 #[derive(Debug, HashStable)]
1710 pub struct VariantDef {
1711 /// `DefId` that identifies the variant itself.
1712 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1714 /// `DefId` that identifies the variant's constructor.
1715 /// If this variant is a struct variant, then this is `None`.
1716 pub ctor_def_id: Option<DefId>,
1717 /// Variant or struct name.
1718 #[stable_hasher(project(name))]
1720 /// Discriminant of this variant.
1721 pub discr: VariantDiscr,
1722 /// Fields of this variant.
1723 pub fields: Vec<FieldDef>,
1724 /// Type of constructor of variant.
1725 pub ctor_kind: CtorKind,
1726 /// Flags of the variant (e.g. is field list non-exhaustive)?
1727 flags: VariantFlags,
1728 /// Variant is obtained as part of recovering from a syntactic error.
1729 /// May be incomplete or bogus.
1730 pub recovered: bool,
1733 impl<'tcx> VariantDef {
1734 /// Creates a new `VariantDef`.
1736 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1737 /// represents an enum variant).
1739 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1740 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1742 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1743 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1744 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1745 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1746 /// built-in trait), and we do not want to load attributes twice.
1748 /// If someone speeds up attribute loading to not be a performance concern, they can
1749 /// remove this hack and use the constructor `DefId` everywhere.
1753 variant_did: Option<DefId>,
1754 ctor_def_id: Option<DefId>,
1755 discr: VariantDiscr,
1756 fields: Vec<FieldDef>,
1757 ctor_kind: CtorKind,
1763 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1764 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1765 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1768 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1769 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1770 debug!("found non-exhaustive field list for {:?}", parent_did);
1771 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1772 } else if let Some(variant_did) = variant_did {
1773 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1774 debug!("found non-exhaustive field list for {:?}", variant_did);
1775 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1780 def_id: variant_did.unwrap_or(parent_did),
1791 /// Is this field list non-exhaustive?
1793 pub fn is_field_list_non_exhaustive(&self) -> bool {
1794 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1798 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1799 pub enum VariantDiscr {
1800 /// Explicit value for this variant, i.e., `X = 123`.
1801 /// The `DefId` corresponds to the embedded constant.
1804 /// The previous variant's discriminant plus one.
1805 /// For efficiency reasons, the distance from the
1806 /// last `Explicit` discriminant is being stored,
1807 /// or `0` for the first variant, if it has none.
1811 #[derive(Debug, HashStable)]
1812 pub struct FieldDef {
1814 #[stable_hasher(project(name))]
1816 pub vis: Visibility,
1819 /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
1821 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1823 /// The initialism *ADT* stands for an [*algebraic data type (ADT)*][adt].
1824 /// This is slightly wrong because `union`s are not ADTs.
1825 /// Moreover, Rust only allows recursive data types through indirection.
1827 /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
1829 /// The `DefId` of the struct, enum or union item.
1831 /// Variants of the ADT. If this is a struct or union, then there will be a single variant.
1832 pub variants: IndexVec<VariantIdx, VariantDef>,
1833 /// Flags of the ADT (e.g., is this a struct? is this non-exhaustive?).
1835 /// Repr options provided by the user.
1836 pub repr: ReprOptions,
1839 impl PartialOrd for AdtDef {
1840 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1841 Some(self.cmp(&other))
1845 /// There should be only one AdtDef for each `did`, therefore
1846 /// it is fine to implement `Ord` only based on `did`.
1847 impl Ord for AdtDef {
1848 fn cmp(&self, other: &AdtDef) -> Ordering {
1849 self.did.cmp(&other.did)
1853 impl PartialEq for AdtDef {
1854 // `AdtDef`s are always interned, and this is part of `TyS` equality.
1856 fn eq(&self, other: &Self) -> bool {
1857 ptr::eq(self, other)
1861 impl Eq for AdtDef {}
1863 impl Hash for AdtDef {
1865 fn hash<H: Hasher>(&self, s: &mut H) {
1866 (self as *const AdtDef).hash(s)
1870 impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef {
1871 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1876 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1878 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1879 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1881 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1884 let hash: Fingerprint = CACHE.with(|cache| {
1885 let addr = self as *const AdtDef as usize;
1886 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1887 let ty::AdtDef { did, ref variants, ref flags, ref repr } = *self;
1889 let mut hasher = StableHasher::new();
1890 did.hash_stable(hcx, &mut hasher);
1891 variants.hash_stable(hcx, &mut hasher);
1892 flags.hash_stable(hcx, &mut hasher);
1893 repr.hash_stable(hcx, &mut hasher);
1899 hash.hash_stable(hcx, hasher);
1903 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1910 impl Into<DataTypeKind> for AdtKind {
1911 fn into(self) -> DataTypeKind {
1913 AdtKind::Struct => DataTypeKind::Struct,
1914 AdtKind::Union => DataTypeKind::Union,
1915 AdtKind::Enum => DataTypeKind::Enum,
1921 #[derive(RustcEncodable, RustcDecodable, Default, HashStable)]
1922 pub struct ReprFlags: u8 {
1923 const IS_C = 1 << 0;
1924 const IS_SIMD = 1 << 1;
1925 const IS_TRANSPARENT = 1 << 2;
1926 // Internal only for now. If true, don't reorder fields.
1927 const IS_LINEAR = 1 << 3;
1928 // If true, don't expose any niche to type's context.
1929 const HIDE_NICHE = 1 << 4;
1930 // Any of these flags being set prevent field reordering optimisation.
1931 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1932 ReprFlags::IS_SIMD.bits |
1933 ReprFlags::IS_LINEAR.bits;
1937 /// Represents the repr options provided by the user,
1938 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default, HashStable)]
1939 pub struct ReprOptions {
1940 pub int: Option<attr::IntType>,
1941 pub align: Option<Align>,
1942 pub pack: Option<Align>,
1943 pub flags: ReprFlags,
1947 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
1948 let mut flags = ReprFlags::empty();
1949 let mut size = None;
1950 let mut max_align: Option<Align> = None;
1951 let mut min_pack: Option<Align> = None;
1952 for attr in tcx.get_attrs(did).iter() {
1953 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
1954 flags.insert(match r {
1955 attr::ReprC => ReprFlags::IS_C,
1956 attr::ReprPacked(pack) => {
1957 let pack = Align::from_bytes(pack as u64).unwrap();
1958 min_pack = Some(if let Some(min_pack) = min_pack {
1965 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1966 attr::ReprNoNiche => ReprFlags::HIDE_NICHE,
1967 attr::ReprSimd => ReprFlags::IS_SIMD,
1968 attr::ReprInt(i) => {
1972 attr::ReprAlign(align) => {
1973 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
1980 // This is here instead of layout because the choice must make it into metadata.
1981 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
1982 flags.insert(ReprFlags::IS_LINEAR);
1984 ReprOptions { int: size, align: max_align, pack: min_pack, flags }
1988 pub fn simd(&self) -> bool {
1989 self.flags.contains(ReprFlags::IS_SIMD)
1992 pub fn c(&self) -> bool {
1993 self.flags.contains(ReprFlags::IS_C)
1996 pub fn packed(&self) -> bool {
2000 pub fn transparent(&self) -> bool {
2001 self.flags.contains(ReprFlags::IS_TRANSPARENT)
2004 pub fn linear(&self) -> bool {
2005 self.flags.contains(ReprFlags::IS_LINEAR)
2008 pub fn hide_niche(&self) -> bool {
2009 self.flags.contains(ReprFlags::HIDE_NICHE)
2012 pub fn discr_type(&self) -> attr::IntType {
2013 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2016 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2017 /// layout" optimizations, such as representing `Foo<&T>` as a
2019 pub fn inhibit_enum_layout_opt(&self) -> bool {
2020 self.c() || self.int.is_some()
2023 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2024 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2025 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2026 if let Some(pack) = self.pack {
2027 if pack.bytes() == 1 {
2031 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2034 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2035 pub fn inhibit_union_abi_opt(&self) -> bool {
2041 /// Creates a new `AdtDef`.
2046 variants: IndexVec<VariantIdx, VariantDef>,
2049 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2050 let mut flags = AdtFlags::NO_ADT_FLAGS;
2052 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2053 debug!("found non-exhaustive variant list for {:?}", did);
2054 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2057 flags |= match kind {
2058 AdtKind::Enum => AdtFlags::IS_ENUM,
2059 AdtKind::Union => AdtFlags::IS_UNION,
2060 AdtKind::Struct => AdtFlags::IS_STRUCT,
2063 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2064 flags |= AdtFlags::HAS_CTOR;
2067 let attrs = tcx.get_attrs(did);
2068 if attr::contains_name(&attrs, sym::fundamental) {
2069 flags |= AdtFlags::IS_FUNDAMENTAL;
2071 if Some(did) == tcx.lang_items().phantom_data() {
2072 flags |= AdtFlags::IS_PHANTOM_DATA;
2074 if Some(did) == tcx.lang_items().owned_box() {
2075 flags |= AdtFlags::IS_BOX;
2077 if Some(did) == tcx.lang_items().manually_drop() {
2078 flags |= AdtFlags::IS_MANUALLY_DROP;
2081 AdtDef { did, variants, flags, repr }
2084 /// Returns `true` if this is a struct.
2086 pub fn is_struct(&self) -> bool {
2087 self.flags.contains(AdtFlags::IS_STRUCT)
2090 /// Returns `true` if this is a union.
2092 pub fn is_union(&self) -> bool {
2093 self.flags.contains(AdtFlags::IS_UNION)
2096 /// Returns `true` if this is a enum.
2098 pub fn is_enum(&self) -> bool {
2099 self.flags.contains(AdtFlags::IS_ENUM)
2102 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2104 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2105 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2108 /// Returns the kind of the ADT.
2110 pub fn adt_kind(&self) -> AdtKind {
2113 } else if self.is_union() {
2120 /// Returns a description of this abstract data type.
2121 pub fn descr(&self) -> &'static str {
2122 match self.adt_kind() {
2123 AdtKind::Struct => "struct",
2124 AdtKind::Union => "union",
2125 AdtKind::Enum => "enum",
2129 /// Returns a description of a variant of this abstract data type.
2131 pub fn variant_descr(&self) -> &'static str {
2132 match self.adt_kind() {
2133 AdtKind::Struct => "struct",
2134 AdtKind::Union => "union",
2135 AdtKind::Enum => "variant",
2139 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2141 pub fn has_ctor(&self) -> bool {
2142 self.flags.contains(AdtFlags::HAS_CTOR)
2145 /// Returns `true` if this type is `#[fundamental]` for the purposes
2146 /// of coherence checking.
2148 pub fn is_fundamental(&self) -> bool {
2149 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2152 /// Returns `true` if this is `PhantomData<T>`.
2154 pub fn is_phantom_data(&self) -> bool {
2155 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2158 /// Returns `true` if this is Box<T>.
2160 pub fn is_box(&self) -> bool {
2161 self.flags.contains(AdtFlags::IS_BOX)
2164 /// Returns `true` if this is `ManuallyDrop<T>`.
2166 pub fn is_manually_drop(&self) -> bool {
2167 self.flags.contains(AdtFlags::IS_MANUALLY_DROP)
2170 /// Returns `true` if this type has a destructor.
2171 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2172 self.destructor(tcx).is_some()
2175 /// Asserts this is a struct or union and returns its unique variant.
2176 pub fn non_enum_variant(&self) -> &VariantDef {
2177 assert!(self.is_struct() || self.is_union());
2178 &self.variants[VariantIdx::new(0)]
2182 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> {
2183 tcx.predicates_of(self.did)
2186 /// Returns an iterator over all fields contained
2189 pub fn all_fields(&self) -> impl Iterator<Item = &FieldDef> + Clone {
2190 self.variants.iter().flat_map(|v| v.fields.iter())
2193 pub fn is_payloadfree(&self) -> bool {
2194 !self.variants.is_empty() && self.variants.iter().all(|v| v.fields.is_empty())
2197 /// Return a `VariantDef` given a variant id.
2198 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2199 self.variants.iter().find(|v| v.def_id == vid).expect("variant_with_id: unknown variant")
2202 /// Return a `VariantDef` given a constructor id.
2203 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2206 .find(|v| v.ctor_def_id == Some(cid))
2207 .expect("variant_with_ctor_id: unknown variant")
2210 /// Return the index of `VariantDef` given a variant id.
2211 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2214 .find(|(_, v)| v.def_id == vid)
2215 .expect("variant_index_with_id: unknown variant")
2219 /// Return the index of `VariantDef` given a constructor id.
2220 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2223 .find(|(_, v)| v.ctor_def_id == Some(cid))
2224 .expect("variant_index_with_ctor_id: unknown variant")
2228 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2230 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2231 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2232 Res::Def(DefKind::Struct, _)
2233 | Res::Def(DefKind::Union, _)
2234 | Res::Def(DefKind::TyAlias, _)
2235 | Res::Def(DefKind::AssocTy, _)
2237 | Res::SelfCtor(..) => self.non_enum_variant(),
2238 _ => bug!("unexpected res {:?} in variant_of_res", res),
2243 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2244 let param_env = tcx.param_env(expr_did);
2245 let repr_type = self.repr.discr_type();
2246 match tcx.const_eval_poly(expr_did) {
2248 let ty = repr_type.to_ty(tcx);
2249 if let Some(b) = val.try_to_bits_for_ty(tcx, param_env, ty) {
2250 trace!("discriminants: {} ({:?})", b, repr_type);
2251 Some(Discr { val: b, ty })
2253 info!("invalid enum discriminant: {:#?}", val);
2254 crate::mir::interpret::struct_error(
2255 tcx.at(tcx.def_span(expr_did)),
2256 "constant evaluation of enum discriminant resulted in non-integer",
2263 let msg = match err {
2264 ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted => {
2265 "enum discriminant evaluation failed"
2267 ErrorHandled::TooGeneric => "enum discriminant depends on generics",
2269 tcx.sess.delay_span_bug(tcx.def_span(expr_did), msg);
2276 pub fn discriminants(
2279 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2280 let repr_type = self.repr.discr_type();
2281 let initial = repr_type.initial_discriminant(tcx);
2282 let mut prev_discr = None::<Discr<'tcx>>;
2283 self.variants.iter_enumerated().map(move |(i, v)| {
2284 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2285 if let VariantDiscr::Explicit(expr_did) = v.discr {
2286 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2290 prev_discr = Some(discr);
2297 pub fn variant_range(&self) -> Range<VariantIdx> {
2298 VariantIdx::new(0)..VariantIdx::new(self.variants.len())
2301 /// Computes the discriminant value used by a specific variant.
2302 /// Unlike `discriminants`, this is (amortized) constant-time,
2303 /// only doing at most one query for evaluating an explicit
2304 /// discriminant (the last one before the requested variant),
2305 /// assuming there are no constant-evaluation errors there.
2307 pub fn discriminant_for_variant(
2310 variant_index: VariantIdx,
2312 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2313 let explicit_value = val
2314 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2315 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
2316 explicit_value.checked_add(tcx, offset as u128).0
2319 /// Yields a `DefId` for the discriminant and an offset to add to it
2320 /// Alternatively, if there is no explicit discriminant, returns the
2321 /// inferred discriminant directly.
2322 pub fn discriminant_def_for_variant(&self, variant_index: VariantIdx) -> (Option<DefId>, u32) {
2323 let mut explicit_index = variant_index.as_u32();
2326 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2327 ty::VariantDiscr::Relative(0) => {
2331 ty::VariantDiscr::Relative(distance) => {
2332 explicit_index -= distance;
2334 ty::VariantDiscr::Explicit(did) => {
2335 expr_did = Some(did);
2340 (expr_did, variant_index.as_u32() - explicit_index)
2343 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2344 tcx.adt_destructor(self.did)
2347 /// Returns a list of types such that `Self: Sized` if and only
2348 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2350 /// Oddly enough, checking that the sized-constraint is `Sized` is
2351 /// actually more expressive than checking all members:
2352 /// the `Sized` trait is inductive, so an associated type that references
2353 /// `Self` would prevent its containing ADT from being `Sized`.
2355 /// Due to normalization being eager, this applies even if
2356 /// the associated type is behind a pointer (e.g., issue #31299).
2357 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2358 tcx.adt_sized_constraint(self.did).0
2362 impl<'tcx> FieldDef {
2363 /// Returns the type of this field. The `subst` is typically obtained
2364 /// via the second field of `TyKind::AdtDef`.
2365 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2366 tcx.type_of(self.did).subst(tcx, subst)
2370 /// Represents the various closure traits in the language. This
2371 /// will determine the type of the environment (`self`, in the
2372 /// desugaring) argument that the closure expects.
2374 /// You can get the environment type of a closure using
2375 /// `tcx.closure_env_ty()`.
2376 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2377 #[derive(HashStable)]
2378 pub enum ClosureKind {
2379 // Warning: Ordering is significant here! The ordering is chosen
2380 // because the trait Fn is a subtrait of FnMut and so in turn, and
2381 // hence we order it so that Fn < FnMut < FnOnce.
2387 impl<'tcx> ClosureKind {
2388 // This is the initial value used when doing upvar inference.
2389 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2391 pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
2393 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem, None),
2394 ClosureKind::FnMut => tcx.require_lang_item(FnMutTraitLangItem, None),
2395 ClosureKind::FnOnce => tcx.require_lang_item(FnOnceTraitLangItem, None),
2399 /// Returns `true` if this a type that impls this closure kind
2400 /// must also implement `other`.
2401 pub fn extends(self, other: ty::ClosureKind) -> bool {
2402 match (self, other) {
2403 (ClosureKind::Fn, ClosureKind::Fn) => true,
2404 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2405 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2406 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2407 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2408 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2413 /// Returns the representative scalar type for this closure kind.
2414 /// See `TyS::to_opt_closure_kind` for more details.
2415 pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
2417 ty::ClosureKind::Fn => tcx.types.i8,
2418 ty::ClosureKind::FnMut => tcx.types.i16,
2419 ty::ClosureKind::FnOnce => tcx.types.i32,
2425 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2427 hir::Mutability::Mut => MutBorrow,
2428 hir::Mutability::Not => ImmBorrow,
2432 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2433 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2434 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2436 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2438 MutBorrow => hir::Mutability::Mut,
2439 ImmBorrow => hir::Mutability::Not,
2441 // We have no type corresponding to a unique imm borrow, so
2442 // use `&mut`. It gives all the capabilities of an `&uniq`
2443 // and hence is a safe "over approximation".
2444 UniqueImmBorrow => hir::Mutability::Mut,
2448 pub fn to_user_str(&self) -> &'static str {
2450 MutBorrow => "mutable",
2451 ImmBorrow => "immutable",
2452 UniqueImmBorrow => "uniquely immutable",
2457 pub type Attributes<'tcx> = &'tcx [ast::Attribute];
2459 #[derive(Debug, PartialEq, Eq)]
2460 pub enum ImplOverlapKind {
2461 /// These impls are always allowed to overlap.
2463 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
2466 /// These impls are allowed to overlap, but that raises
2467 /// an issue #33140 future-compatibility warning.
2469 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2470 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2472 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2473 /// that difference, making what reduces to the following set of impls:
2477 /// impl Trait for dyn Send + Sync {}
2478 /// impl Trait for dyn Sync + Send {}
2481 /// Obviously, once we made these types be identical, that code causes a coherence
2482 /// error and a fairly big headache for us. However, luckily for us, the trait
2483 /// `Trait` used in this case is basically a marker trait, and therefore having
2484 /// overlapping impls for it is sound.
2486 /// To handle this, we basically regard the trait as a marker trait, with an additional
2487 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2488 /// it has the following restrictions:
2490 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2492 /// 2. The trait-ref of both impls must be equal.
2493 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2495 /// 4. Neither of the impls can have any where-clauses.
2497 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2501 impl<'tcx> TyCtxt<'tcx> {
2502 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
2503 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2506 /// Returns an iterator of the `DefId`s for all body-owners in this
2507 /// crate. If you would prefer to iterate over the bodies
2508 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2509 pub fn body_owners(self) -> impl Iterator<Item = LocalDefId> + Captures<'tcx> + 'tcx {
2514 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2517 pub fn par_body_owners<F: Fn(LocalDefId) + sync::Sync + sync::Send>(self, f: F) {
2518 par_iter(&self.hir().krate().body_ids)
2519 .for_each(|&body_id| f(self.hir().body_owner_def_id(body_id)));
2522 pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
2523 self.associated_items(id)
2524 .in_definition_order()
2525 .filter(|item| item.kind == AssocKind::Fn && item.defaultness.has_value())
2528 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2529 self.associated_items(did).in_definition_order().any(|item| item.relevant_for_never())
2532 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
2535 .and_then(|def_id| self.hir().get(self.hir().as_local_hir_id(def_id)).ident())
2538 pub fn opt_associated_item(self, def_id: DefId) -> Option<&'tcx AssocItem> {
2539 let is_associated_item = if let Some(def_id) = def_id.as_local() {
2540 match self.hir().get(self.hir().as_local_hir_id(def_id)) {
2541 Node::TraitItem(_) | Node::ImplItem(_) => true,
2545 match self.def_kind(def_id) {
2546 DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy => true,
2551 is_associated_item.then(|| self.associated_item(def_id))
2554 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2555 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2558 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2559 variant.fields.iter().position(|field| self.hygienic_eq(ident, field.ident, variant.def_id))
2562 /// Returns `true` if the impls are the same polarity and the trait either
2563 /// has no items or is annotated `#[marker]` and prevents item overrides.
2564 pub fn impls_are_allowed_to_overlap(
2568 ) -> Option<ImplOverlapKind> {
2569 // If either trait impl references an error, they're allowed to overlap,
2570 // as one of them essentially doesn't exist.
2571 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
2572 || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
2574 return Some(ImplOverlapKind::Permitted { marker: false });
2577 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2578 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
2579 // `#[rustc_reservation_impl]` impls don't overlap with anything
2581 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2584 return Some(ImplOverlapKind::Permitted { marker: false });
2586 (ImplPolarity::Positive, ImplPolarity::Negative)
2587 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
2588 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2590 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2595 (ImplPolarity::Positive, ImplPolarity::Positive)
2596 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2599 let is_marker_overlap = {
2600 let is_marker_impl = |def_id: DefId| -> bool {
2601 let trait_ref = self.impl_trait_ref(def_id);
2602 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2604 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2607 if is_marker_overlap {
2609 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2612 Some(ImplOverlapKind::Permitted { marker: true })
2614 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2615 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2616 if self_ty1 == self_ty2 {
2618 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2621 return Some(ImplOverlapKind::Issue33140);
2624 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2625 def_id1, def_id2, self_ty1, self_ty2
2631 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
2636 /// Returns `ty::VariantDef` if `res` refers to a struct,
2637 /// or variant or their constructors, panics otherwise.
2638 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2640 Res::Def(DefKind::Variant, did) => {
2641 let enum_did = self.parent(did).unwrap();
2642 self.adt_def(enum_did).variant_with_id(did)
2644 Res::Def(DefKind::Struct | DefKind::Union, did) => self.adt_def(did).non_enum_variant(),
2645 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2646 let variant_did = self.parent(variant_ctor_did).unwrap();
2647 let enum_did = self.parent(variant_did).unwrap();
2648 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2650 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2651 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2652 self.adt_def(struct_did).non_enum_variant()
2654 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
2658 pub fn item_name(self, id: DefId) -> Symbol {
2659 if id.index == CRATE_DEF_INDEX {
2660 self.original_crate_name(id.krate)
2662 let def_key = self.def_key(id);
2663 match def_key.disambiguated_data.data {
2664 // The name of a constructor is that of its parent.
2665 rustc_hir::definitions::DefPathData::Ctor => {
2666 self.item_name(DefId { krate: id.krate, index: def_key.parent.unwrap() })
2668 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2669 bug!("item_name: no name for {:?}", self.def_path(id));
2675 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2676 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
2678 ty::InstanceDef::Item(did) => self.optimized_mir(did),
2679 ty::InstanceDef::VtableShim(..)
2680 | ty::InstanceDef::ReifyShim(..)
2681 | ty::InstanceDef::Intrinsic(..)
2682 | ty::InstanceDef::FnPtrShim(..)
2683 | ty::InstanceDef::Virtual(..)
2684 | ty::InstanceDef::ClosureOnceShim { .. }
2685 | ty::InstanceDef::DropGlue(..)
2686 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance),
2690 /// Gets the attributes of a definition.
2691 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
2692 if let Some(did) = did.as_local() {
2693 self.hir().attrs(self.hir().as_local_hir_id(did))
2695 self.item_attrs(did)
2699 /// Determines whether an item is annotated with an attribute.
2700 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
2701 attr::contains_name(&self.get_attrs(did), attr)
2704 /// Returns `true` if this is an `auto trait`.
2705 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2706 self.trait_def(trait_def_id).has_auto_impl
2709 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2710 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2713 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
2714 /// If it implements no trait, returns `None`.
2715 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2716 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2719 /// If the given defid describes a method belonging to an impl, returns the
2720 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
2721 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2722 self.opt_associated_item(def_id).and_then(|trait_item| match trait_item.container {
2723 TraitContainer(_) => None,
2724 ImplContainer(def_id) => Some(def_id),
2728 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2729 /// with the name of the crate containing the impl.
2730 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2731 if let Some(impl_did) = impl_did.as_local() {
2732 let hir_id = self.hir().as_local_hir_id(impl_did);
2733 Ok(self.hir().span(hir_id))
2735 Err(self.crate_name(impl_did.krate))
2739 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
2740 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2741 /// definition's parent/scope to perform comparison.
2742 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2743 // We could use `Ident::eq` here, but we deliberately don't. The name
2744 // comparison fails frequently, and we want to avoid the expensive
2745 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
2746 use_name.name == def_name.name
2750 .hygienic_eq(def_name.span.ctxt(), self.expansion_that_defined(def_parent_def_id))
2753 fn expansion_that_defined(self, scope: DefId) -> ExpnId {
2754 match scope.as_local() {
2755 Some(scope) => self.hir().definitions().expansion_that_defined(scope),
2756 None => ExpnId::root(),
2760 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
2761 ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope));
2765 pub fn adjust_ident_and_get_scope(
2770 ) -> (Ident, DefId) {
2772 match ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope))
2774 Some(actual_expansion) => {
2775 self.hir().definitions().parent_module_of_macro_def(actual_expansion)
2777 None => self.parent_module(block).to_def_id(),
2782 pub fn is_object_safe(self, key: DefId) -> bool {
2783 self.object_safety_violations(key).is_empty()
2787 #[derive(Clone, HashStable)]
2788 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
2790 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
2791 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
2792 if let Some(def_id) = def_id.as_local() {
2793 if let Node::Item(item) = tcx.hir().get(tcx.hir().as_local_hir_id(def_id)) {
2794 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
2795 return opaque_ty.impl_trait_fn;
2802 pub fn provide(providers: &mut ty::query::Providers<'_>) {
2803 context::provide(providers);
2804 erase_regions::provide(providers);
2805 layout::provide(providers);
2806 super::util::bug::provide(providers);
2807 *providers = ty::query::Providers {
2808 trait_impls_of: trait_def::trait_impls_of_provider,
2809 all_local_trait_impls: trait_def::all_local_trait_impls,
2814 /// A map for the local crate mapping each type to a vector of its
2815 /// inherent impls. This is not meant to be used outside of coherence;
2816 /// rather, you should request the vector for a specific type via
2817 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2818 /// (constructing this map requires touching the entire crate).
2819 #[derive(Clone, Debug, Default, HashStable)]
2820 pub struct CrateInherentImpls {
2821 pub inherent_impls: DefIdMap<Vec<DefId>>,
2824 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2825 pub struct SymbolName {
2826 // FIXME: we don't rely on interning or equality here - better have
2827 // this be a `&'tcx str`.
2832 pub fn new(name: &str) -> SymbolName {
2833 SymbolName { name: Symbol::intern(name) }
2837 impl PartialOrd for SymbolName {
2838 fn partial_cmp(&self, other: &SymbolName) -> Option<Ordering> {
2839 self.name.as_str().partial_cmp(&other.name.as_str())
2843 /// Ordering must use the chars to ensure reproducible builds.
2844 impl Ord for SymbolName {
2845 fn cmp(&self, other: &SymbolName) -> Ordering {
2846 self.name.as_str().cmp(&other.name.as_str())
2850 impl fmt::Display for SymbolName {
2851 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2852 fmt::Display::fmt(&self.name, fmt)
2856 impl fmt::Debug for SymbolName {
2857 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2858 fmt::Display::fmt(&self.name, fmt)