1 // ignore-tidy-filelength
3 pub use self::Variance::*;
4 pub use self::AssocItemContainer::*;
5 pub use self::BorrowKind::*;
6 pub use self::IntVarValue::*;
7 pub use self::fold::{TypeFoldable, TypeVisitor};
9 use crate::hir::{map as hir_map, GlobMap, TraitMap};
11 use crate::hir::def::{Res, DefKind, CtorOf, CtorKind, ExportMap};
12 use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
13 use rustc_data_structures::svh::Svh;
14 use rustc_macros::HashStable;
15 use crate::ich::Fingerprint;
16 use crate::ich::StableHashingContext;
17 use crate::infer::canonical::Canonical;
18 use crate::middle::cstore::CrateStoreDyn;
19 use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
20 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
21 use crate::mir::ReadOnlyBodyCache;
22 use crate::mir::interpret::{GlobalId, ErrorHandled};
23 use crate::mir::GeneratorLayout;
24 use crate::session::CrateDisambiguator;
25 use crate::traits::{self, Reveal};
27 use crate::ty::layout::VariantIdx;
28 use crate::ty::subst::{Subst, InternalSubsts, SubstsRef};
29 use crate::ty::util::{IntTypeExt, Discr};
30 use crate::ty::walk::TypeWalker;
31 use crate::util::captures::Captures;
32 use crate::util::nodemap::{NodeMap, NodeSet, DefIdMap, FxHashMap};
33 use arena::SyncDroplessArena;
34 use crate::session::DataTypeKind;
36 use rustc_serialize::{self, Encodable, Encoder};
37 use rustc_target::abi::Align;
38 use std::cell::RefCell;
39 use std::cmp::{self, Ordering};
41 use std::hash::{Hash, Hasher};
43 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
47 use syntax::ast::{self, Name, Ident, NodeId};
49 use syntax_pos::symbol::{kw, sym, Symbol};
50 use syntax_pos::hygiene::ExpnId;
54 use rustc_data_structures::fx::{FxIndexMap};
55 use rustc_data_structures::stable_hasher::{StableHasher, HashStable};
56 use rustc_index::vec::{Idx, IndexVec};
60 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
61 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
62 pub use self::sty::{InferTy, ParamTy, ParamConst, InferConst, ProjectionTy, ExistentialPredicate};
63 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
64 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
65 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
66 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const, ConstKind};
67 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
68 pub use self::sty::RegionKind;
69 pub use self::sty::{TyVid, IntVid, FloatVid, ConstVid, RegionVid};
70 pub use self::sty::BoundRegion::*;
71 pub use self::sty::InferTy::*;
72 pub use self::sty::RegionKind::*;
73 pub use self::sty::TyKind::*;
74 pub use crate::ty::diagnostics::*;
76 pub use self::binding::BindingMode;
77 pub use self::binding::BindingMode::*;
79 pub use self::context::{TyCtxt, FreeRegionInfo, AllArenas, tls, keep_local};
80 pub use self::context::{Lift, GeneratorInteriorTypeCause, TypeckTables, CtxtInterners, GlobalCtxt};
81 pub use self::context::{
82 UserTypeAnnotationIndex, UserType, CanonicalUserType,
83 CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
86 pub use self::instance::{Instance, InstanceDef};
88 pub use self::structural_match::search_for_structural_match_violation;
89 pub use self::structural_match::type_marked_structural;
90 pub use self::structural_match::NonStructuralMatchTy;
92 pub use self::trait_def::TraitDef;
94 pub use self::query::queries;
107 pub mod inhabitedness;
123 mod structural_impls;
124 mod structural_match;
130 pub struct ResolverOutputs {
131 pub definitions: hir_map::Definitions,
132 pub cstore: Box<CrateStoreDyn>,
133 pub extern_crate_map: NodeMap<CrateNum>,
134 pub trait_map: TraitMap,
135 pub maybe_unused_trait_imports: NodeSet,
136 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
137 pub export_map: ExportMap<NodeId>,
138 pub glob_map: GlobMap,
139 /// Extern prelude entries. The value is `true` if the entry was introduced
140 /// via `extern crate` item and not `--extern` option or compiler built-in.
141 pub extern_prelude: FxHashMap<Name, bool>,
144 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
145 pub enum AssocItemContainer {
146 TraitContainer(DefId),
147 ImplContainer(DefId),
150 impl AssocItemContainer {
151 /// Asserts that this is the `DefId` of an associated item declared
152 /// in a trait, and returns the trait `DefId`.
153 pub fn assert_trait(&self) -> DefId {
155 TraitContainer(id) => id,
156 _ => bug!("associated item has wrong container type: {:?}", self)
160 pub fn id(&self) -> DefId {
162 TraitContainer(id) => id,
163 ImplContainer(id) => id,
168 /// The "header" of an impl is everything outside the body: a Self type, a trait
169 /// ref (in the case of a trait impl), and a set of predicates (from the
170 /// bounds / where-clauses).
171 #[derive(Clone, Debug, TypeFoldable)]
172 pub struct ImplHeader<'tcx> {
173 pub impl_def_id: DefId,
174 pub self_ty: Ty<'tcx>,
175 pub trait_ref: Option<TraitRef<'tcx>>,
176 pub predicates: Vec<Predicate<'tcx>>,
179 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
180 pub enum ImplPolarity {
181 /// `impl Trait for Type`
183 /// `impl !Trait for Type`
185 /// `#[rustc_reservation_impl] impl Trait for Type`
187 /// This is a "stability hack", not a real Rust feature.
188 /// See #64631 for details.
192 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
193 pub struct AssocItem {
195 #[stable_hasher(project(name))]
199 pub defaultness: hir::Defaultness,
200 pub container: AssocItemContainer,
202 /// Whether this is a method with an explicit self
203 /// as its first argument, allowing method calls.
204 pub method_has_self_argument: bool,
207 #[derive(Copy, Clone, PartialEq, Debug, HashStable)]
216 pub fn def_kind(&self) -> DefKind {
218 AssocKind::Const => DefKind::AssocConst,
219 AssocKind::Method => DefKind::Method,
220 AssocKind::Type => DefKind::AssocTy,
221 AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
225 /// Tests whether the associated item admits a non-trivial implementation
227 pub fn relevant_for_never(&self) -> bool {
229 AssocKind::OpaqueTy |
231 AssocKind::Type => true,
232 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
233 AssocKind::Method => !self.method_has_self_argument,
237 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
239 ty::AssocKind::Method => {
240 // We skip the binder here because the binder would deanonymize all
241 // late-bound regions, and we don't want method signatures to show up
242 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
243 // regions just fine, showing `fn(&MyType)`.
244 tcx.fn_sig(self.def_id).skip_binder().to_string()
246 ty::AssocKind::Type => format!("type {};", self.ident),
247 // FIXME(type_alias_impl_trait): we should print bounds here too.
248 ty::AssocKind::OpaqueTy => format!("type {};", self.ident),
249 ty::AssocKind::Const => {
250 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
256 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
257 pub enum Visibility {
258 /// Visible everywhere (including in other crates).
260 /// Visible only in the given crate-local module.
262 /// Not visible anywhere in the local crate. This is the visibility of private external items.
266 pub trait DefIdTree: Copy {
267 fn parent(self, id: DefId) -> Option<DefId>;
269 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
270 if descendant.krate != ancestor.krate {
274 while descendant != ancestor {
275 match self.parent(descendant) {
276 Some(parent) => descendant = parent,
277 None => return false,
284 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
285 fn parent(self, id: DefId) -> Option<DefId> {
286 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
291 pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
292 match visibility.node {
293 hir::VisibilityKind::Public => Visibility::Public,
294 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
295 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
296 // If there is no resolution, `resolve` will have already reported an error, so
297 // assume that the visibility is public to avoid reporting more privacy errors.
298 Res::Err => Visibility::Public,
299 def => Visibility::Restricted(def.def_id()),
301 hir::VisibilityKind::Inherited => {
302 Visibility::Restricted(tcx.hir().get_module_parent(id))
307 /// Returns `true` if an item with this visibility is accessible from the given block.
308 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
309 let restriction = match self {
310 // Public items are visible everywhere.
311 Visibility::Public => return true,
312 // Private items from other crates are visible nowhere.
313 Visibility::Invisible => return false,
314 // Restricted items are visible in an arbitrary local module.
315 Visibility::Restricted(other) if other.krate != module.krate => return false,
316 Visibility::Restricted(module) => module,
319 tree.is_descendant_of(module, restriction)
322 /// Returns `true` if this visibility is at least as accessible as the given visibility
323 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
324 let vis_restriction = match vis {
325 Visibility::Public => return self == Visibility::Public,
326 Visibility::Invisible => return true,
327 Visibility::Restricted(module) => module,
330 self.is_accessible_from(vis_restriction, tree)
333 // Returns `true` if this item is visible anywhere in the local crate.
334 pub fn is_visible_locally(self) -> bool {
336 Visibility::Public => true,
337 Visibility::Restricted(def_id) => def_id.is_local(),
338 Visibility::Invisible => false,
343 #[derive(Copy, Clone, PartialEq, RustcDecodable, RustcEncodable, HashStable)]
345 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
346 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
347 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
348 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
351 /// The crate variances map is computed during typeck and contains the
352 /// variance of every item in the local crate. You should not use it
353 /// directly, because to do so will make your pass dependent on the
354 /// HIR of every item in the local crate. Instead, use
355 /// `tcx.variances_of()` to get the variance for a *particular*
357 #[derive(HashStable)]
358 pub struct CrateVariancesMap<'tcx> {
359 /// For each item with generics, maps to a vector of the variance
360 /// of its generics. If an item has no generics, it will have no
362 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
366 /// `a.xform(b)` combines the variance of a context with the
367 /// variance of a type with the following meaning. If we are in a
368 /// context with variance `a`, and we encounter a type argument in
369 /// a position with variance `b`, then `a.xform(b)` is the new
370 /// variance with which the argument appears.
376 /// Here, the "ambient" variance starts as covariant. `*mut T` is
377 /// invariant with respect to `T`, so the variance in which the
378 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
379 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
380 /// respect to its type argument `T`, and hence the variance of
381 /// the `i32` here is `Invariant.xform(Covariant)`, which results
382 /// (again) in `Invariant`.
386 /// fn(*const Vec<i32>, *mut Vec<i32)
388 /// The ambient variance is covariant. A `fn` type is
389 /// contravariant with respect to its parameters, so the variance
390 /// within which both pointer types appear is
391 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
392 /// T` is covariant with respect to `T`, so the variance within
393 /// which the first `Vec<i32>` appears is
394 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
395 /// is true for its `i32` argument. In the `*mut T` case, the
396 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
397 /// and hence the outermost type is `Invariant` with respect to
398 /// `Vec<i32>` (and its `i32` argument).
400 /// Source: Figure 1 of "Taming the Wildcards:
401 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
402 pub fn xform(self, v: ty::Variance) -> ty::Variance {
404 // Figure 1, column 1.
405 (ty::Covariant, ty::Covariant) => ty::Covariant,
406 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
407 (ty::Covariant, ty::Invariant) => ty::Invariant,
408 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
410 // Figure 1, column 2.
411 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
412 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
413 (ty::Contravariant, ty::Invariant) => ty::Invariant,
414 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
416 // Figure 1, column 3.
417 (ty::Invariant, _) => ty::Invariant,
419 // Figure 1, column 4.
420 (ty::Bivariant, _) => ty::Bivariant,
425 // Contains information needed to resolve types and (in the future) look up
426 // the types of AST nodes.
427 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
428 pub struct CReaderCacheKey {
433 // Flags that we track on types. These flags are propagated upwards
434 // through the type during type construction, so that we can quickly
435 // check whether the type has various kinds of types in it without
436 // recursing over the type itself.
438 pub struct TypeFlags: u32 {
439 const HAS_PARAMS = 1 << 0;
440 const HAS_TY_INFER = 1 << 1;
441 const HAS_RE_INFER = 1 << 2;
442 const HAS_RE_PLACEHOLDER = 1 << 3;
444 /// Does this have any `ReEarlyBound` regions? Used to
445 /// determine whether substitition is required, since those
446 /// represent regions that are bound in a `ty::Generics` and
447 /// hence may be substituted.
448 const HAS_RE_EARLY_BOUND = 1 << 4;
450 /// Does this have any region that "appears free" in the type?
451 /// Basically anything but `ReLateBound` and `ReErased`.
452 const HAS_FREE_REGIONS = 1 << 5;
454 /// Is an error type reachable?
455 const HAS_TY_ERR = 1 << 6;
456 const HAS_PROJECTION = 1 << 7;
458 // FIXME: Rename this to the actual property since it's used for generators too
459 const HAS_TY_CLOSURE = 1 << 8;
461 /// `true` if there are "names" of types and regions and so forth
462 /// that are local to a particular fn
463 const HAS_FREE_LOCAL_NAMES = 1 << 9;
465 /// Present if the type belongs in a local type context.
466 /// Only set for Infer other than Fresh.
467 const KEEP_IN_LOCAL_TCX = 1 << 10;
469 /// Does this have any `ReLateBound` regions? Used to check
470 /// if a global bound is safe to evaluate.
471 const HAS_RE_LATE_BOUND = 1 << 11;
473 const HAS_TY_PLACEHOLDER = 1 << 12;
475 const HAS_CT_INFER = 1 << 13;
476 const HAS_CT_PLACEHOLDER = 1 << 14;
478 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
479 TypeFlags::HAS_RE_EARLY_BOUND.bits;
481 /// Flags representing the nominal content of a type,
482 /// computed by FlagsComputation. If you add a new nominal
483 /// flag, it should be added here too.
484 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
485 TypeFlags::HAS_TY_INFER.bits |
486 TypeFlags::HAS_RE_INFER.bits |
487 TypeFlags::HAS_RE_PLACEHOLDER.bits |
488 TypeFlags::HAS_RE_EARLY_BOUND.bits |
489 TypeFlags::HAS_FREE_REGIONS.bits |
490 TypeFlags::HAS_TY_ERR.bits |
491 TypeFlags::HAS_PROJECTION.bits |
492 TypeFlags::HAS_TY_CLOSURE.bits |
493 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
494 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
495 TypeFlags::HAS_RE_LATE_BOUND.bits |
496 TypeFlags::HAS_TY_PLACEHOLDER.bits |
497 TypeFlags::HAS_CT_INFER.bits |
498 TypeFlags::HAS_CT_PLACEHOLDER.bits;
502 #[allow(rustc::usage_of_ty_tykind)]
503 pub struct TyS<'tcx> {
504 pub kind: TyKind<'tcx>,
505 pub flags: TypeFlags,
507 /// This is a kind of confusing thing: it stores the smallest
510 /// (a) the binder itself captures nothing but
511 /// (b) all the late-bound things within the type are captured
512 /// by some sub-binder.
514 /// So, for a type without any late-bound things, like `u32`, this
515 /// will be *innermost*, because that is the innermost binder that
516 /// captures nothing. But for a type `&'D u32`, where `'D` is a
517 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
518 /// -- the binder itself does not capture `D`, but `D` is captured
519 /// by an inner binder.
521 /// We call this concept an "exclusive" binder `D` because all
522 /// De Bruijn indices within the type are contained within `0..D`
524 outer_exclusive_binder: ty::DebruijnIndex,
527 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
528 #[cfg(target_arch = "x86_64")]
529 static_assert_size!(TyS<'_>, 32);
531 impl<'tcx> Ord for TyS<'tcx> {
532 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
533 self.kind.cmp(&other.kind)
537 impl<'tcx> PartialOrd for TyS<'tcx> {
538 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
539 Some(self.kind.cmp(&other.kind))
543 impl<'tcx> PartialEq for TyS<'tcx> {
545 fn eq(&self, other: &TyS<'tcx>) -> bool {
549 impl<'tcx> Eq for TyS<'tcx> {}
551 impl<'tcx> Hash for TyS<'tcx> {
552 fn hash<H: Hasher>(&self, s: &mut H) {
553 (self as *const TyS<'_>).hash(s)
557 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
558 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
562 // The other fields just provide fast access to information that is
563 // also contained in `kind`, so no need to hash them.
566 outer_exclusive_binder: _,
569 kind.hash_stable(hcx, hasher);
573 #[rustc_diagnostic_item = "Ty"]
574 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
576 impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {}
577 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {}
579 pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
582 /// A dummy type used to force `List` to be unsized while not requiring references to it be wide
584 type OpaqueListContents;
587 /// A wrapper for slices with the additional invariant
588 /// that the slice is interned and no other slice with
589 /// the same contents can exist in the same context.
590 /// This means we can use pointer for both
591 /// equality comparisons and hashing.
592 /// Note: `Slice` was already taken by the `Ty`.
597 opaque: OpaqueListContents,
600 unsafe impl<T: Sync> Sync for List<T> {}
602 impl<T: Copy> List<T> {
604 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
605 assert!(!mem::needs_drop::<T>());
606 assert!(mem::size_of::<T>() != 0);
607 assert!(slice.len() != 0);
609 // Align up the size of the len (usize) field
610 let align = mem::align_of::<T>();
611 let align_mask = align - 1;
612 let offset = mem::size_of::<usize>();
613 let offset = (offset + align_mask) & !align_mask;
615 let size = offset + slice.len() * mem::size_of::<T>();
617 let mem = arena.alloc_raw(
619 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
621 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
623 result.len = slice.len();
625 // Write the elements
626 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
627 arena_slice.copy_from_slice(slice);
634 impl<T: fmt::Debug> fmt::Debug for List<T> {
635 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
640 impl<T: Encodable> Encodable for List<T> {
642 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
647 impl<T> Ord for List<T> where T: Ord {
648 fn cmp(&self, other: &List<T>) -> Ordering {
649 if self == other { Ordering::Equal } else {
650 <[T] as Ord>::cmp(&**self, &**other)
655 impl<T> PartialOrd for List<T> where T: PartialOrd {
656 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
657 if self == other { Some(Ordering::Equal) } else {
658 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
663 impl<T: PartialEq> PartialEq for List<T> {
665 fn eq(&self, other: &List<T>) -> bool {
669 impl<T: Eq> Eq for List<T> {}
671 impl<T> Hash for List<T> {
673 fn hash<H: Hasher>(&self, s: &mut H) {
674 (self as *const List<T>).hash(s)
678 impl<T> Deref for List<T> {
681 fn deref(&self) -> &[T] {
686 impl<T> AsRef<[T]> for List<T> {
688 fn as_ref(&self) -> &[T] {
690 slice::from_raw_parts(self.data.as_ptr(), self.len)
695 impl<'a, T> IntoIterator for &'a List<T> {
697 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
699 fn into_iter(self) -> Self::IntoIter {
704 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
708 pub fn empty<'a>() -> &'a List<T> {
709 #[repr(align(64), C)]
710 struct EmptySlice([u8; 64]);
711 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
712 assert!(mem::align_of::<T>() <= 64);
714 &*(&EMPTY_SLICE as *const _ as *const List<T>)
719 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
720 pub struct UpvarPath {
721 pub hir_id: hir::HirId,
724 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
725 /// the original var ID (that is, the root variable that is referenced
726 /// by the upvar) and the ID of the closure expression.
727 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
729 pub var_path: UpvarPath,
730 pub closure_expr_id: LocalDefId,
733 #[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
734 pub enum BorrowKind {
735 /// Data must be immutable and is aliasable.
738 /// Data must be immutable but not aliasable. This kind of borrow
739 /// cannot currently be expressed by the user and is used only in
740 /// implicit closure bindings. It is needed when the closure
741 /// is borrowing or mutating a mutable referent, e.g.:
743 /// let x: &mut isize = ...;
744 /// let y = || *x += 5;
746 /// If we were to try to translate this closure into a more explicit
747 /// form, we'd encounter an error with the code as written:
749 /// struct Env { x: & &mut isize }
750 /// let x: &mut isize = ...;
751 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
752 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
754 /// This is then illegal because you cannot mutate a `&mut` found
755 /// in an aliasable location. To solve, you'd have to translate with
756 /// an `&mut` borrow:
758 /// struct Env { x: & &mut isize }
759 /// let x: &mut isize = ...;
760 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
761 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
763 /// Now the assignment to `**env.x` is legal, but creating a
764 /// mutable pointer to `x` is not because `x` is not mutable. We
765 /// could fix this by declaring `x` as `let mut x`. This is ok in
766 /// user code, if awkward, but extra weird for closures, since the
767 /// borrow is hidden.
769 /// So we introduce a "unique imm" borrow -- the referent is
770 /// immutable, but not aliasable. This solves the problem. For
771 /// simplicity, we don't give users the way to express this
772 /// borrow, it's just used when translating closures.
775 /// Data is mutable and not aliasable.
779 /// Information describing the capture of an upvar. This is computed
780 /// during `typeck`, specifically by `regionck`.
781 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
782 pub enum UpvarCapture<'tcx> {
783 /// Upvar is captured by value. This is always true when the
784 /// closure is labeled `move`, but can also be true in other cases
785 /// depending on inference.
788 /// Upvar is captured by reference.
789 ByRef(UpvarBorrow<'tcx>),
792 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
793 pub struct UpvarBorrow<'tcx> {
794 /// The kind of borrow: by-ref upvars have access to shared
795 /// immutable borrows, which are not part of the normal language
797 pub kind: BorrowKind,
799 /// Region of the resulting reference.
800 pub region: ty::Region<'tcx>,
803 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
804 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
806 #[derive(Copy, Clone, TypeFoldable)]
807 pub struct ClosureUpvar<'tcx> {
813 #[derive(Clone, Copy, PartialEq, Eq)]
814 pub enum IntVarValue {
816 UintType(ast::UintTy),
819 #[derive(Clone, Copy, PartialEq, Eq)]
820 pub struct FloatVarValue(pub ast::FloatTy);
822 impl ty::EarlyBoundRegion {
823 pub fn to_bound_region(&self) -> ty::BoundRegion {
824 ty::BoundRegion::BrNamed(self.def_id, self.name)
827 /// Does this early bound region have a name? Early bound regions normally
828 /// always have names except when using anonymous lifetimes (`'_`).
829 pub fn has_name(&self) -> bool {
830 self.name != kw::UnderscoreLifetime
834 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
835 pub enum GenericParamDefKind {
839 object_lifetime_default: ObjectLifetimeDefault,
840 synthetic: Option<hir::SyntheticTyParamKind>,
845 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
846 pub struct GenericParamDef {
851 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
852 /// on generic parameter `'a`/`T`, asserts data behind the parameter
853 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
854 pub pure_wrt_drop: bool,
856 pub kind: GenericParamDefKind,
859 impl GenericParamDef {
860 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
861 if let GenericParamDefKind::Lifetime = self.kind {
862 ty::EarlyBoundRegion {
868 bug!("cannot convert a non-lifetime parameter def to an early bound region")
872 pub fn to_bound_region(&self) -> ty::BoundRegion {
873 if let GenericParamDefKind::Lifetime = self.kind {
874 self.to_early_bound_region_data().to_bound_region()
876 bug!("cannot convert a non-lifetime parameter def to an early bound region")
882 pub struct GenericParamCount {
883 pub lifetimes: usize,
888 /// Information about the formal type/lifetime parameters associated
889 /// with an item or method. Analogous to `hir::Generics`.
891 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
892 /// `Self` (optionally), `Lifetime` params..., `Type` params...
893 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
894 pub struct Generics {
895 pub parent: Option<DefId>,
896 pub parent_count: usize,
897 pub params: Vec<GenericParamDef>,
899 /// Reverse map to the `index` field of each `GenericParamDef`.
900 #[stable_hasher(ignore)]
901 pub param_def_id_to_index: FxHashMap<DefId, u32>,
904 pub has_late_bound_regions: Option<Span>,
907 impl<'tcx> Generics {
908 pub fn count(&self) -> usize {
909 self.parent_count + self.params.len()
912 pub fn own_counts(&self) -> GenericParamCount {
913 // We could cache this as a property of `GenericParamCount`, but
914 // the aim is to refactor this away entirely eventually and the
915 // presence of this method will be a constant reminder.
916 let mut own_counts: GenericParamCount = Default::default();
918 for param in &self.params {
920 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
921 GenericParamDefKind::Type { .. } => own_counts.types += 1,
922 GenericParamDefKind::Const => own_counts.consts += 1,
929 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
930 if self.own_requires_monomorphization() {
934 if let Some(parent_def_id) = self.parent {
935 let parent = tcx.generics_of(parent_def_id);
936 parent.requires_monomorphization(tcx)
942 pub fn own_requires_monomorphization(&self) -> bool {
943 for param in &self.params {
945 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
946 GenericParamDefKind::Lifetime => {}
954 param: &EarlyBoundRegion,
956 ) -> &'tcx GenericParamDef {
957 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
958 let param = &self.params[index as usize];
960 GenericParamDefKind::Lifetime => param,
961 _ => bug!("expected lifetime parameter, but found another generic parameter")
964 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
965 .region_param(param, tcx)
969 /// Returns the `GenericParamDef` associated with this `ParamTy`.
970 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
971 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
972 let param = &self.params[index as usize];
974 GenericParamDefKind::Type { .. } => param,
975 _ => bug!("expected type parameter, but found another generic parameter")
978 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
979 .type_param(param, tcx)
983 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
984 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
985 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
986 let param = &self.params[index as usize];
988 GenericParamDefKind::Const => param,
989 _ => bug!("expected const parameter, but found another generic parameter")
992 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
993 .const_param(param, tcx)
998 /// Bounds on generics.
999 #[derive(Copy, Clone, Default, Debug, RustcEncodable, RustcDecodable, HashStable)]
1000 pub struct GenericPredicates<'tcx> {
1001 pub parent: Option<DefId>,
1002 pub predicates: &'tcx [(Predicate<'tcx>, Span)],
1005 impl<'tcx> GenericPredicates<'tcx> {
1009 substs: SubstsRef<'tcx>,
1010 ) -> InstantiatedPredicates<'tcx> {
1011 let mut instantiated = InstantiatedPredicates::empty();
1012 self.instantiate_into(tcx, &mut instantiated, substs);
1016 pub fn instantiate_own(
1019 substs: SubstsRef<'tcx>,
1020 ) -> InstantiatedPredicates<'tcx> {
1021 InstantiatedPredicates {
1022 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1026 fn instantiate_into(
1029 instantiated: &mut InstantiatedPredicates<'tcx>,
1030 substs: SubstsRef<'tcx>,
1032 if let Some(def_id) = self.parent {
1033 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1035 instantiated.predicates.extend(
1036 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1040 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
1041 let mut instantiated = InstantiatedPredicates::empty();
1042 self.instantiate_identity_into(tcx, &mut instantiated);
1046 fn instantiate_identity_into(
1049 instantiated: &mut InstantiatedPredicates<'tcx>,
1051 if let Some(def_id) = self.parent {
1052 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1054 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1057 pub fn instantiate_supertrait(
1060 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1061 ) -> InstantiatedPredicates<'tcx> {
1062 assert_eq!(self.parent, None);
1063 InstantiatedPredicates {
1064 predicates: self.predicates.iter().map(|(pred, _)| {
1065 pred.subst_supertrait(tcx, poly_trait_ref)
1071 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1072 #[derive(HashStable, TypeFoldable)]
1073 pub enum Predicate<'tcx> {
1074 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1075 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1076 /// would be the type parameters.
1077 Trait(PolyTraitPredicate<'tcx>),
1080 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1083 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1085 /// `where <T as TraitRef>::Name == X`, approximately.
1086 /// See the `ProjectionPredicate` struct for details.
1087 Projection(PolyProjectionPredicate<'tcx>),
1089 /// No syntax: `T` well-formed.
1090 WellFormed(Ty<'tcx>),
1092 /// Trait must be object-safe.
1095 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1096 /// for some substitutions `...` and `T` being a closure type.
1097 /// Satisfied (or refuted) once we know the closure's kind.
1098 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
1101 Subtype(PolySubtypePredicate<'tcx>),
1103 /// Constant initializer must evaluate successfully.
1104 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1107 /// The crate outlives map is computed during typeck and contains the
1108 /// outlives of every item in the local crate. You should not use it
1109 /// directly, because to do so will make your pass dependent on the
1110 /// HIR of every item in the local crate. Instead, use
1111 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1113 #[derive(HashStable)]
1114 pub struct CratePredicatesMap<'tcx> {
1115 /// For each struct with outlive bounds, maps to a vector of the
1116 /// predicate of its outlive bounds. If an item has no outlives
1117 /// bounds, it will have no entry.
1118 pub predicates: FxHashMap<DefId, &'tcx [(ty::Predicate<'tcx>, Span)]>,
1121 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1122 fn as_ref(&self) -> &Predicate<'tcx> {
1127 impl<'tcx> Predicate<'tcx> {
1128 /// Performs a substitution suitable for going from a
1129 /// poly-trait-ref to supertraits that must hold if that
1130 /// poly-trait-ref holds. This is slightly different from a normal
1131 /// substitution in terms of what happens with bound regions. See
1132 /// lengthy comment below for details.
1133 pub fn subst_supertrait(
1136 trait_ref: &ty::PolyTraitRef<'tcx>,
1137 ) -> ty::Predicate<'tcx> {
1138 // The interaction between HRTB and supertraits is not entirely
1139 // obvious. Let me walk you (and myself) through an example.
1141 // Let's start with an easy case. Consider two traits:
1143 // trait Foo<'a>: Bar<'a,'a> { }
1144 // trait Bar<'b,'c> { }
1146 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1147 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1148 // knew that `Foo<'x>` (for any 'x) then we also know that
1149 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1150 // normal substitution.
1152 // In terms of why this is sound, the idea is that whenever there
1153 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1154 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1155 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1158 // Another example to be careful of is this:
1160 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1161 // trait Bar1<'b,'c> { }
1163 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1164 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1165 // reason is similar to the previous example: any impl of
1166 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1167 // basically we would want to collapse the bound lifetimes from
1168 // the input (`trait_ref`) and the supertraits.
1170 // To achieve this in practice is fairly straightforward. Let's
1171 // consider the more complicated scenario:
1173 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1174 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1175 // where both `'x` and `'b` would have a DB index of 1.
1176 // The substitution from the input trait-ref is therefore going to be
1177 // `'a => 'x` (where `'x` has a DB index of 1).
1178 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1179 // early-bound parameter and `'b' is a late-bound parameter with a
1181 // - If we replace `'a` with `'x` from the input, it too will have
1182 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1183 // just as we wanted.
1185 // There is only one catch. If we just apply the substitution `'a
1186 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1187 // adjust the DB index because we substituting into a binder (it
1188 // tries to be so smart...) resulting in `for<'x> for<'b>
1189 // Bar1<'x,'b>` (we have no syntax for this, so use your
1190 // imagination). Basically the 'x will have DB index of 2 and 'b
1191 // will have DB index of 1. Not quite what we want. So we apply
1192 // the substitution to the *contents* of the trait reference,
1193 // rather than the trait reference itself (put another way, the
1194 // substitution code expects equal binding levels in the values
1195 // from the substitution and the value being substituted into, and
1196 // this trick achieves that).
1198 let substs = &trait_ref.skip_binder().substs;
1200 Predicate::Trait(ref binder) =>
1201 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1202 Predicate::Subtype(ref binder) =>
1203 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1204 Predicate::RegionOutlives(ref binder) =>
1205 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1206 Predicate::TypeOutlives(ref binder) =>
1207 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1208 Predicate::Projection(ref binder) =>
1209 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1210 Predicate::WellFormed(data) =>
1211 Predicate::WellFormed(data.subst(tcx, substs)),
1212 Predicate::ObjectSafe(trait_def_id) =>
1213 Predicate::ObjectSafe(trait_def_id),
1214 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1215 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1216 Predicate::ConstEvaluatable(def_id, const_substs) =>
1217 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1222 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1223 #[derive(HashStable, TypeFoldable)]
1224 pub struct TraitPredicate<'tcx> {
1225 pub trait_ref: TraitRef<'tcx>
1228 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1230 impl<'tcx> TraitPredicate<'tcx> {
1231 pub fn def_id(&self) -> DefId {
1232 self.trait_ref.def_id
1235 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
1236 self.trait_ref.input_types()
1239 pub fn self_ty(&self) -> Ty<'tcx> {
1240 self.trait_ref.self_ty()
1244 impl<'tcx> PolyTraitPredicate<'tcx> {
1245 pub fn def_id(&self) -> DefId {
1246 // Ok to skip binder since trait `DefId` does not care about regions.
1247 self.skip_binder().def_id()
1251 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1252 #[derive(HashStable, TypeFoldable)]
1253 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1254 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1255 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1256 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1257 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1258 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1260 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1261 #[derive(HashStable, TypeFoldable)]
1262 pub struct SubtypePredicate<'tcx> {
1263 pub a_is_expected: bool,
1267 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1269 /// This kind of predicate has no *direct* correspondent in the
1270 /// syntax, but it roughly corresponds to the syntactic forms:
1272 /// 1. `T: TraitRef<..., Item = Type>`
1273 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1275 /// In particular, form #1 is "desugared" to the combination of a
1276 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1277 /// predicates. Form #2 is a broader form in that it also permits
1278 /// equality between arbitrary types. Processing an instance of
1279 /// Form #2 eventually yields one of these `ProjectionPredicate`
1280 /// instances to normalize the LHS.
1281 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1282 #[derive(HashStable, TypeFoldable)]
1283 pub struct ProjectionPredicate<'tcx> {
1284 pub projection_ty: ProjectionTy<'tcx>,
1288 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1290 impl<'tcx> PolyProjectionPredicate<'tcx> {
1291 /// Returns the `DefId` of the associated item being projected.
1292 pub fn item_def_id(&self) -> DefId {
1293 self.skip_binder().projection_ty.item_def_id
1297 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_>) -> PolyTraitRef<'tcx> {
1298 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1299 // `self.0.trait_ref` is permitted to have escaping regions.
1300 // This is because here `self` has a `Binder` and so does our
1301 // return value, so we are preserving the number of binding
1303 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1306 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1307 self.map_bound(|predicate| predicate.ty)
1310 /// The `DefId` of the `TraitItem` for the associated type.
1312 /// Note that this is not the `DefId` of the `TraitRef` containing this
1313 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1314 pub fn projection_def_id(&self) -> DefId {
1315 // Ok to skip binder since trait `DefId` does not care about regions.
1316 self.skip_binder().projection_ty.item_def_id
1320 pub trait ToPolyTraitRef<'tcx> {
1321 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1324 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1325 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1326 ty::Binder::dummy(self.clone())
1330 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1331 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1332 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1336 pub trait ToPredicate<'tcx> {
1337 fn to_predicate(&self) -> Predicate<'tcx>;
1340 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1341 fn to_predicate(&self) -> Predicate<'tcx> {
1342 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1343 trait_ref: self.clone()
1348 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1349 fn to_predicate(&self) -> Predicate<'tcx> {
1350 ty::Predicate::Trait(self.to_poly_trait_predicate())
1354 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1355 fn to_predicate(&self) -> Predicate<'tcx> {
1356 Predicate::RegionOutlives(self.clone())
1360 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1361 fn to_predicate(&self) -> Predicate<'tcx> {
1362 Predicate::TypeOutlives(self.clone())
1366 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1367 fn to_predicate(&self) -> Predicate<'tcx> {
1368 Predicate::Projection(self.clone())
1372 // A custom iterator used by `Predicate::walk_tys`.
1373 enum WalkTysIter<'tcx, I, J, K>
1374 where I: Iterator<Item = Ty<'tcx>>,
1375 J: Iterator<Item = Ty<'tcx>>,
1376 K: Iterator<Item = Ty<'tcx>>
1380 Two(Ty<'tcx>, Ty<'tcx>),
1386 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1387 where I: Iterator<Item = Ty<'tcx>>,
1388 J: Iterator<Item = Ty<'tcx>>,
1389 K: Iterator<Item = Ty<'tcx>>
1391 type Item = Ty<'tcx>;
1393 fn next(&mut self) -> Option<Ty<'tcx>> {
1395 WalkTysIter::None => None,
1396 WalkTysIter::One(item) => {
1397 *self = WalkTysIter::None;
1400 WalkTysIter::Two(item1, item2) => {
1401 *self = WalkTysIter::One(item2);
1404 WalkTysIter::Types(ref mut iter) => {
1407 WalkTysIter::InputTypes(ref mut iter) => {
1410 WalkTysIter::ProjectionTypes(ref mut iter) => {
1417 impl<'tcx> Predicate<'tcx> {
1418 /// Iterates over the types in this predicate. Note that in all
1419 /// cases this is skipping over a binder, so late-bound regions
1420 /// with depth 0 are bound by the predicate.
1421 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1423 ty::Predicate::Trait(ref data) => {
1424 WalkTysIter::InputTypes(data.skip_binder().input_types())
1426 ty::Predicate::Subtype(binder) => {
1427 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1428 WalkTysIter::Two(a, b)
1430 ty::Predicate::TypeOutlives(binder) => {
1431 WalkTysIter::One(binder.skip_binder().0)
1433 ty::Predicate::RegionOutlives(..) => {
1436 ty::Predicate::Projection(ref data) => {
1437 let inner = data.skip_binder();
1438 WalkTysIter::ProjectionTypes(
1439 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1441 ty::Predicate::WellFormed(data) => {
1442 WalkTysIter::One(data)
1444 ty::Predicate::ObjectSafe(_trait_def_id) => {
1447 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1448 WalkTysIter::Types(closure_substs.types())
1450 ty::Predicate::ConstEvaluatable(_, substs) => {
1451 WalkTysIter::Types(substs.types())
1456 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1458 Predicate::Trait(ref t) => {
1459 Some(t.to_poly_trait_ref())
1461 Predicate::Projection(..) |
1462 Predicate::Subtype(..) |
1463 Predicate::RegionOutlives(..) |
1464 Predicate::WellFormed(..) |
1465 Predicate::ObjectSafe(..) |
1466 Predicate::ClosureKind(..) |
1467 Predicate::TypeOutlives(..) |
1468 Predicate::ConstEvaluatable(..) => {
1474 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1476 Predicate::TypeOutlives(data) => {
1479 Predicate::Trait(..) |
1480 Predicate::Projection(..) |
1481 Predicate::Subtype(..) |
1482 Predicate::RegionOutlives(..) |
1483 Predicate::WellFormed(..) |
1484 Predicate::ObjectSafe(..) |
1485 Predicate::ClosureKind(..) |
1486 Predicate::ConstEvaluatable(..) => {
1493 /// Represents the bounds declared on a particular set of type
1494 /// parameters. Should eventually be generalized into a flag list of
1495 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1496 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1497 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1498 /// the `GenericPredicates` are expressed in terms of the bound type
1499 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1500 /// represented a set of bounds for some particular instantiation,
1501 /// meaning that the generic parameters have been substituted with
1506 /// struct Foo<T, U: Bar<T>> { ... }
1508 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1509 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1510 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1511 /// [usize:Bar<isize>]]`.
1512 #[derive(Clone, Debug, TypeFoldable)]
1513 pub struct InstantiatedPredicates<'tcx> {
1514 pub predicates: Vec<Predicate<'tcx>>,
1517 impl<'tcx> InstantiatedPredicates<'tcx> {
1518 pub fn empty() -> InstantiatedPredicates<'tcx> {
1519 InstantiatedPredicates { predicates: vec![] }
1522 pub fn is_empty(&self) -> bool {
1523 self.predicates.is_empty()
1527 rustc_index::newtype_index! {
1528 /// "Universes" are used during type- and trait-checking in the
1529 /// presence of `for<..>` binders to control what sets of names are
1530 /// visible. Universes are arranged into a tree: the root universe
1531 /// contains names that are always visible. Each child then adds a new
1532 /// set of names that are visible, in addition to those of its parent.
1533 /// We say that the child universe "extends" the parent universe with
1536 /// To make this more concrete, consider this program:
1540 /// fn bar<T>(x: T) {
1541 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1545 /// The struct name `Foo` is in the root universe U0. But the type
1546 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1547 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1548 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1549 /// region `'a` is in a universe U2 that extends U1, because we can
1550 /// name it inside the fn type but not outside.
1552 /// Universes are used to do type- and trait-checking around these
1553 /// "forall" binders (also called **universal quantification**). The
1554 /// idea is that when, in the body of `bar`, we refer to `T` as a
1555 /// type, we aren't referring to any type in particular, but rather a
1556 /// kind of "fresh" type that is distinct from all other types we have
1557 /// actually declared. This is called a **placeholder** type, and we
1558 /// use universes to talk about this. In other words, a type name in
1559 /// universe 0 always corresponds to some "ground" type that the user
1560 /// declared, but a type name in a non-zero universe is a placeholder
1561 /// type -- an idealized representative of "types in general" that we
1562 /// use for checking generic functions.
1563 pub struct UniverseIndex {
1565 DEBUG_FORMAT = "U{}",
1569 impl UniverseIndex {
1570 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1572 /// Returns the "next" universe index in order -- this new index
1573 /// is considered to extend all previous universes. This
1574 /// corresponds to entering a `forall` quantifier. So, for
1575 /// example, suppose we have this type in universe `U`:
1578 /// for<'a> fn(&'a u32)
1581 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1582 /// new universe that extends `U` -- in this new universe, we can
1583 /// name the region `'a`, but that region was not nameable from
1584 /// `U` because it was not in scope there.
1585 pub fn next_universe(self) -> UniverseIndex {
1586 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1589 /// Returns `true` if `self` can name a name from `other` -- in other words,
1590 /// if the set of names in `self` is a superset of those in
1591 /// `other` (`self >= other`).
1592 pub fn can_name(self, other: UniverseIndex) -> bool {
1593 self.private >= other.private
1596 /// Returns `true` if `self` cannot name some names from `other` -- in other
1597 /// words, if the set of names in `self` is a strict subset of
1598 /// those in `other` (`self < other`).
1599 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1600 self.private < other.private
1604 /// The "placeholder index" fully defines a placeholder region.
1605 /// Placeholder regions are identified by both a **universe** as well
1606 /// as a "bound-region" within that universe. The `bound_region` is
1607 /// basically a name -- distinct bound regions within the same
1608 /// universe are just two regions with an unknown relationship to one
1610 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1611 pub struct Placeholder<T> {
1612 pub universe: UniverseIndex,
1616 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1618 T: HashStable<StableHashingContext<'a>>,
1620 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1621 self.universe.hash_stable(hcx, hasher);
1622 self.name.hash_stable(hcx, hasher);
1626 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1628 pub type PlaceholderType = Placeholder<BoundVar>;
1630 pub type PlaceholderConst = Placeholder<BoundVar>;
1632 /// When type checking, we use the `ParamEnv` to track
1633 /// details about the set of where-clauses that are in scope at this
1634 /// particular point.
1635 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TypeFoldable)]
1636 pub struct ParamEnv<'tcx> {
1637 /// `Obligation`s that the caller must satisfy. This is basically
1638 /// the set of bounds on the in-scope type parameters, translated
1639 /// into `Obligation`s, and elaborated and normalized.
1640 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1642 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1643 /// want `Reveal::All` -- note that this is always paired with an
1644 /// empty environment. To get that, use `ParamEnv::reveal()`.
1645 pub reveal: traits::Reveal,
1647 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1648 /// register that `def_id` (useful for transitioning to the chalk trait
1650 pub def_id: Option<DefId>,
1653 impl<'tcx> ParamEnv<'tcx> {
1654 /// Construct a trait environment suitable for contexts where
1655 /// there are no where-clauses in scope. Hidden types (like `impl
1656 /// Trait`) are left hidden, so this is suitable for ordinary
1659 pub fn empty() -> Self {
1660 Self::new(List::empty(), Reveal::UserFacing, None)
1663 /// Construct a trait environment with no where-clauses in scope
1664 /// where the values of all `impl Trait` and other hidden types
1665 /// are revealed. This is suitable for monomorphized, post-typeck
1666 /// environments like codegen or doing optimizations.
1668 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1669 /// or invoke `param_env.with_reveal_all()`.
1671 pub fn reveal_all() -> Self {
1672 Self::new(List::empty(), Reveal::All, None)
1675 /// Construct a trait environment with the given set of predicates.
1678 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1680 def_id: Option<DefId>
1682 ty::ParamEnv { caller_bounds, reveal, def_id }
1685 /// Returns a new parameter environment with the same clauses, but
1686 /// which "reveals" the true results of projections in all cases
1687 /// (even for associated types that are specializable). This is
1688 /// the desired behavior during codegen and certain other special
1689 /// contexts; normally though we want to use `Reveal::UserFacing`,
1690 /// which is the default.
1691 pub fn with_reveal_all(self) -> Self {
1692 ty::ParamEnv { reveal: Reveal::All, ..self }
1695 /// Returns this same environment but with no caller bounds.
1696 pub fn without_caller_bounds(self) -> Self {
1697 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1700 /// Creates a suitable environment in which to perform trait
1701 /// queries on the given value. When type-checking, this is simply
1702 /// the pair of the environment plus value. But when reveal is set to
1703 /// All, then if `value` does not reference any type parameters, we will
1704 /// pair it with the empty environment. This improves caching and is generally
1707 /// N.B., we preserve the environment when type-checking because it
1708 /// is possible for the user to have wacky where-clauses like
1709 /// `where Box<u32>: Copy`, which are clearly never
1710 /// satisfiable. We generally want to behave as if they were true,
1711 /// although the surrounding function is never reachable.
1712 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1714 Reveal::UserFacing => {
1722 if value.has_placeholders()
1723 || value.needs_infer()
1724 || value.has_param_types()
1732 param_env: self.without_caller_bounds(),
1741 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1742 pub struct ParamEnvAnd<'tcx, T> {
1743 pub param_env: ParamEnv<'tcx>,
1747 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1748 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1749 (self.param_env, self.value)
1753 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1755 T: HashStable<StableHashingContext<'a>>,
1757 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1763 param_env.hash_stable(hcx, hasher);
1764 value.hash_stable(hcx, hasher);
1768 #[derive(Copy, Clone, Debug, HashStable)]
1769 pub struct Destructor {
1770 /// The `DefId` of the destructor method
1775 #[derive(HashStable)]
1776 pub struct AdtFlags: u32 {
1777 const NO_ADT_FLAGS = 0;
1778 /// Indicates whether the ADT is an enum.
1779 const IS_ENUM = 1 << 0;
1780 /// Indicates whether the ADT is a union.
1781 const IS_UNION = 1 << 1;
1782 /// Indicates whether the ADT is a struct.
1783 const IS_STRUCT = 1 << 2;
1784 /// Indicates whether the ADT is a struct and has a constructor.
1785 const HAS_CTOR = 1 << 3;
1786 /// Indicates whether the type is a `PhantomData`.
1787 const IS_PHANTOM_DATA = 1 << 4;
1788 /// Indicates whether the type has a `#[fundamental]` attribute.
1789 const IS_FUNDAMENTAL = 1 << 5;
1790 /// Indicates whether the type is a `Box`.
1791 const IS_BOX = 1 << 6;
1792 /// Indicates whether the type is an `Arc`.
1793 const IS_ARC = 1 << 7;
1794 /// Indicates whether the type is an `Rc`.
1795 const IS_RC = 1 << 8;
1796 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1797 /// (i.e., this flag is never set unless this ADT is an enum).
1798 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1803 #[derive(HashStable)]
1804 pub struct VariantFlags: u32 {
1805 const NO_VARIANT_FLAGS = 0;
1806 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1807 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1811 /// Definition of a variant -- a struct's fields or a enum variant.
1812 #[derive(Debug, HashStable)]
1813 pub struct VariantDef {
1814 /// `DefId` that identifies the variant itself.
1815 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1817 /// `DefId` that identifies the variant's constructor.
1818 /// If this variant is a struct variant, then this is `None`.
1819 pub ctor_def_id: Option<DefId>,
1820 /// Variant or struct name.
1821 #[stable_hasher(project(name))]
1823 /// Discriminant of this variant.
1824 pub discr: VariantDiscr,
1825 /// Fields of this variant.
1826 pub fields: Vec<FieldDef>,
1827 /// Type of constructor of variant.
1828 pub ctor_kind: CtorKind,
1829 /// Flags of the variant (e.g. is field list non-exhaustive)?
1830 flags: VariantFlags,
1831 /// Variant is obtained as part of recovering from a syntactic error.
1832 /// May be incomplete or bogus.
1833 pub recovered: bool,
1836 impl<'tcx> VariantDef {
1837 /// Creates a new `VariantDef`.
1839 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1840 /// represents an enum variant).
1842 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1843 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1845 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1846 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1847 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1848 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1849 /// built-in trait), and we do not want to load attributes twice.
1851 /// If someone speeds up attribute loading to not be a performance concern, they can
1852 /// remove this hack and use the constructor `DefId` everywhere.
1856 variant_did: Option<DefId>,
1857 ctor_def_id: Option<DefId>,
1858 discr: VariantDiscr,
1859 fields: Vec<FieldDef>,
1860 ctor_kind: CtorKind,
1866 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1867 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1868 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1871 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1872 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1873 debug!("found non-exhaustive field list for {:?}", parent_did);
1874 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1875 } else if let Some(variant_did) = variant_did {
1876 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1877 debug!("found non-exhaustive field list for {:?}", variant_did);
1878 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1883 def_id: variant_did.unwrap_or(parent_did),
1894 /// Is this field list non-exhaustive?
1896 pub fn is_field_list_non_exhaustive(&self) -> bool {
1897 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1901 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1902 pub enum VariantDiscr {
1903 /// Explicit value for this variant, i.e., `X = 123`.
1904 /// The `DefId` corresponds to the embedded constant.
1907 /// The previous variant's discriminant plus one.
1908 /// For efficiency reasons, the distance from the
1909 /// last `Explicit` discriminant is being stored,
1910 /// or `0` for the first variant, if it has none.
1914 #[derive(Debug, HashStable)]
1915 pub struct FieldDef {
1917 #[stable_hasher(project(name))]
1919 pub vis: Visibility,
1922 /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
1924 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1926 /// The initialism *ADT* stands for an [*algebraic data type (ADT)*][adt].
1927 /// This is slightly wrong because `union`s are not ADTs.
1928 /// Moreover, Rust only allows recursive data types through indirection.
1930 /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
1932 /// The `DefId` of the struct, enum or union item.
1934 /// Variants of the ADT. If this is a struct or union, then there will be a single variant.
1935 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1936 /// Flags of the ADT (e.g., is this a struct? is this non-exhaustive?).
1938 /// Repr options provided by the user.
1939 pub repr: ReprOptions,
1942 impl PartialOrd for AdtDef {
1943 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1944 Some(self.cmp(&other))
1948 /// There should be only one AdtDef for each `did`, therefore
1949 /// it is fine to implement `Ord` only based on `did`.
1950 impl Ord for AdtDef {
1951 fn cmp(&self, other: &AdtDef) -> Ordering {
1952 self.did.cmp(&other.did)
1956 impl PartialEq for AdtDef {
1957 // `AdtDef`s are always interned, and this is part of `TyS` equality.
1959 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1962 impl Eq for AdtDef {}
1964 impl Hash for AdtDef {
1966 fn hash<H: Hasher>(&self, s: &mut H) {
1967 (self as *const AdtDef).hash(s)
1971 impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef {
1972 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1977 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1979 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1980 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1982 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1985 let hash: Fingerprint = CACHE.with(|cache| {
1986 let addr = self as *const AdtDef as usize;
1987 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1995 let mut hasher = StableHasher::new();
1996 did.hash_stable(hcx, &mut hasher);
1997 variants.hash_stable(hcx, &mut hasher);
1998 flags.hash_stable(hcx, &mut hasher);
1999 repr.hash_stable(hcx, &mut hasher);
2005 hash.hash_stable(hcx, hasher);
2009 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2010 pub enum AdtKind { Struct, Union, Enum }
2012 impl Into<DataTypeKind> for AdtKind {
2013 fn into(self) -> DataTypeKind {
2015 AdtKind::Struct => DataTypeKind::Struct,
2016 AdtKind::Union => DataTypeKind::Union,
2017 AdtKind::Enum => DataTypeKind::Enum,
2023 #[derive(RustcEncodable, RustcDecodable, Default, HashStable)]
2024 pub struct ReprFlags: u8 {
2025 const IS_C = 1 << 0;
2026 const IS_SIMD = 1 << 1;
2027 const IS_TRANSPARENT = 1 << 2;
2028 // Internal only for now. If true, don't reorder fields.
2029 const IS_LINEAR = 1 << 3;
2031 // Any of these flags being set prevent field reordering optimisation.
2032 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2033 ReprFlags::IS_SIMD.bits |
2034 ReprFlags::IS_LINEAR.bits;
2038 /// Represents the repr options provided by the user,
2039 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable,
2040 Default, HashStable)]
2041 pub struct ReprOptions {
2042 pub int: Option<attr::IntType>,
2043 pub align: Option<Align>,
2044 pub pack: Option<Align>,
2045 pub flags: ReprFlags,
2049 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2050 let mut flags = ReprFlags::empty();
2051 let mut size = None;
2052 let mut max_align: Option<Align> = None;
2053 let mut min_pack: Option<Align> = None;
2054 for attr in tcx.get_attrs(did).iter() {
2055 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2056 flags.insert(match r {
2057 attr::ReprC => ReprFlags::IS_C,
2058 attr::ReprPacked(pack) => {
2059 let pack = Align::from_bytes(pack as u64).unwrap();
2060 min_pack = Some(if let Some(min_pack) = min_pack {
2067 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2068 attr::ReprSimd => ReprFlags::IS_SIMD,
2069 attr::ReprInt(i) => {
2073 attr::ReprAlign(align) => {
2074 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2081 // This is here instead of layout because the choice must make it into metadata.
2082 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2083 flags.insert(ReprFlags::IS_LINEAR);
2085 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2089 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2091 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2093 pub fn packed(&self) -> bool { self.pack.is_some() }
2095 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2097 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2099 pub fn discr_type(&self) -> attr::IntType {
2100 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2103 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2104 /// layout" optimizations, such as representing `Foo<&T>` as a
2106 pub fn inhibit_enum_layout_opt(&self) -> bool {
2107 self.c() || self.int.is_some()
2110 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2111 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2112 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2113 if let Some(pack) = self.pack {
2114 if pack.bytes() == 1 {
2118 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2121 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2122 pub fn inhibit_union_abi_opt(&self) -> bool {
2128 /// Creates a new `AdtDef`.
2133 variants: IndexVec<VariantIdx, VariantDef>,
2136 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2137 let mut flags = AdtFlags::NO_ADT_FLAGS;
2139 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2140 debug!("found non-exhaustive variant list for {:?}", did);
2141 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2144 flags |= match kind {
2145 AdtKind::Enum => AdtFlags::IS_ENUM,
2146 AdtKind::Union => AdtFlags::IS_UNION,
2147 AdtKind::Struct => AdtFlags::IS_STRUCT,
2150 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2151 flags |= AdtFlags::HAS_CTOR;
2154 let attrs = tcx.get_attrs(did);
2155 if attr::contains_name(&attrs, sym::fundamental) {
2156 flags |= AdtFlags::IS_FUNDAMENTAL;
2158 if Some(did) == tcx.lang_items().phantom_data() {
2159 flags |= AdtFlags::IS_PHANTOM_DATA;
2161 if Some(did) == tcx.lang_items().owned_box() {
2162 flags |= AdtFlags::IS_BOX;
2164 if Some(did) == tcx.lang_items().arc() {
2165 flags |= AdtFlags::IS_ARC;
2167 if Some(did) == tcx.lang_items().rc() {
2168 flags |= AdtFlags::IS_RC;
2179 /// Returns `true` if this is a struct.
2181 pub fn is_struct(&self) -> bool {
2182 self.flags.contains(AdtFlags::IS_STRUCT)
2185 /// Returns `true` if this is a union.
2187 pub fn is_union(&self) -> bool {
2188 self.flags.contains(AdtFlags::IS_UNION)
2191 /// Returns `true` if this is a enum.
2193 pub fn is_enum(&self) -> bool {
2194 self.flags.contains(AdtFlags::IS_ENUM)
2197 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2199 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2200 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2203 /// Returns the kind of the ADT.
2205 pub fn adt_kind(&self) -> AdtKind {
2208 } else if self.is_union() {
2215 /// Returns a description of this abstract data type.
2216 pub fn descr(&self) -> &'static str {
2217 match self.adt_kind() {
2218 AdtKind::Struct => "struct",
2219 AdtKind::Union => "union",
2220 AdtKind::Enum => "enum",
2224 /// Returns a description of a variant of this abstract data type.
2226 pub fn variant_descr(&self) -> &'static str {
2227 match self.adt_kind() {
2228 AdtKind::Struct => "struct",
2229 AdtKind::Union => "union",
2230 AdtKind::Enum => "variant",
2234 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2236 pub fn has_ctor(&self) -> bool {
2237 self.flags.contains(AdtFlags::HAS_CTOR)
2240 /// Returns `true` if this type is `#[fundamental]` for the purposes
2241 /// of coherence checking.
2243 pub fn is_fundamental(&self) -> bool {
2244 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2247 /// Returns `true` if this is `PhantomData<T>`.
2249 pub fn is_phantom_data(&self) -> bool {
2250 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2253 /// Returns `true` if this is `Arc<T>`.
2254 pub fn is_arc(&self) -> bool {
2255 self.flags.contains(AdtFlags::IS_ARC)
2258 /// Returns `true` if this is `Rc<T>`.
2259 pub fn is_rc(&self) -> bool {
2260 self.flags.contains(AdtFlags::IS_RC)
2263 /// Returns `true` if this is Box<T>.
2265 pub fn is_box(&self) -> bool {
2266 self.flags.contains(AdtFlags::IS_BOX)
2269 /// Returns `true` if this type has a destructor.
2270 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2271 self.destructor(tcx).is_some()
2274 /// Asserts this is a struct or union and returns its unique variant.
2275 pub fn non_enum_variant(&self) -> &VariantDef {
2276 assert!(self.is_struct() || self.is_union());
2277 &self.variants[VariantIdx::new(0)]
2281 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> {
2282 tcx.predicates_of(self.did)
2285 /// Returns an iterator over all fields contained
2288 pub fn all_fields(&self) -> impl Iterator<Item=&FieldDef> + Clone {
2289 self.variants.iter().flat_map(|v| v.fields.iter())
2292 pub fn is_payloadfree(&self) -> bool {
2293 !self.variants.is_empty() &&
2294 self.variants.iter().all(|v| v.fields.is_empty())
2297 /// Return a `VariantDef` given a variant id.
2298 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2299 self.variants.iter().find(|v| v.def_id == vid)
2300 .expect("variant_with_id: unknown variant")
2303 /// Return a `VariantDef` given a constructor id.
2304 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2305 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2306 .expect("variant_with_ctor_id: unknown variant")
2309 /// Return the index of `VariantDef` given a variant id.
2310 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2311 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2312 .expect("variant_index_with_id: unknown variant").0
2315 /// Return the index of `VariantDef` given a constructor id.
2316 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2317 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2318 .expect("variant_index_with_ctor_id: unknown variant").0
2321 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2323 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2324 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2325 Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
2326 Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) |
2327 Res::SelfCtor(..) => self.non_enum_variant(),
2328 _ => bug!("unexpected res {:?} in variant_of_res", res)
2333 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2334 let param_env = tcx.param_env(expr_did);
2335 let repr_type = self.repr.discr_type();
2336 let substs = InternalSubsts::identity_for_item(tcx, expr_did);
2337 let instance = ty::Instance::new(expr_did, substs);
2338 let cid = GlobalId {
2342 match tcx.const_eval(param_env.and(cid)) {
2344 // FIXME: Find the right type and use it instead of `val.ty` here
2345 if let Some(b) = val.try_eval_bits(tcx, param_env, val.ty) {
2346 trace!("discriminants: {} ({:?})", b, repr_type);
2352 info!("invalid enum discriminant: {:#?}", val);
2353 crate::mir::interpret::struct_error(
2354 tcx.at(tcx.def_span(expr_did)),
2355 "constant evaluation of enum discriminant resulted in non-integer",
2360 Err(ErrorHandled::Reported) => {
2361 if !expr_did.is_local() {
2362 span_bug!(tcx.def_span(expr_did),
2363 "variant discriminant evaluation succeeded \
2364 in its crate but failed locally");
2368 Err(ErrorHandled::TooGeneric) => span_bug!(
2369 tcx.def_span(expr_did),
2370 "enum discriminant depends on generic arguments",
2376 pub fn discriminants(
2379 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2380 let repr_type = self.repr.discr_type();
2381 let initial = repr_type.initial_discriminant(tcx);
2382 let mut prev_discr = None::<Discr<'tcx>>;
2383 self.variants.iter_enumerated().map(move |(i, v)| {
2384 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2385 if let VariantDiscr::Explicit(expr_did) = v.discr {
2386 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2390 prev_discr = Some(discr);
2397 pub fn variant_range(&self) -> Range<VariantIdx> {
2398 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2401 /// Computes the discriminant value used by a specific variant.
2402 /// Unlike `discriminants`, this is (amortized) constant-time,
2403 /// only doing at most one query for evaluating an explicit
2404 /// discriminant (the last one before the requested variant),
2405 /// assuming there are no constant-evaluation errors there.
2407 pub fn discriminant_for_variant(
2410 variant_index: VariantIdx,
2412 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2413 let explicit_value = val
2414 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2415 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
2416 explicit_value.checked_add(tcx, offset as u128).0
2419 /// Yields a `DefId` for the discriminant and an offset to add to it
2420 /// Alternatively, if there is no explicit discriminant, returns the
2421 /// inferred discriminant directly.
2422 pub fn discriminant_def_for_variant(
2424 variant_index: VariantIdx,
2425 ) -> (Option<DefId>, u32) {
2426 let mut explicit_index = variant_index.as_u32();
2429 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2430 ty::VariantDiscr::Relative(0) => {
2434 ty::VariantDiscr::Relative(distance) => {
2435 explicit_index -= distance;
2437 ty::VariantDiscr::Explicit(did) => {
2438 expr_did = Some(did);
2443 (expr_did, variant_index.as_u32() - explicit_index)
2446 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2447 tcx.adt_destructor(self.did)
2450 /// Returns a list of types such that `Self: Sized` if and only
2451 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2453 /// Oddly enough, checking that the sized-constraint is `Sized` is
2454 /// actually more expressive than checking all members:
2455 /// the `Sized` trait is inductive, so an associated type that references
2456 /// `Self` would prevent its containing ADT from being `Sized`.
2458 /// Due to normalization being eager, this applies even if
2459 /// the associated type is behind a pointer (e.g., issue #31299).
2460 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2461 tcx.adt_sized_constraint(self.did).0
2464 fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> {
2465 let result = match ty.kind {
2466 Bool | Char | Int(..) | Uint(..) | Float(..) |
2467 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2468 Array(..) | Closure(..) | Generator(..) | Never => {
2477 GeneratorWitness(..) => {
2478 // these are never sized - return the target type
2485 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2489 Adt(adt, substs) => {
2491 let adt_tys = adt.sized_constraint(tcx);
2492 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2495 .map(|ty| ty.subst(tcx, substs))
2496 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2500 Projection(..) | Opaque(..) => {
2501 // must calculate explicitly.
2502 // FIXME: consider special-casing always-Sized projections
2506 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2509 // perf hack: if there is a `T: Sized` bound, then
2510 // we know that `T` is Sized and do not need to check
2513 let sized_trait = match tcx.lang_items().sized_trait() {
2515 _ => return vec![ty]
2517 let sized_predicate = Binder::dummy(TraitRef {
2518 def_id: sized_trait,
2519 substs: tcx.mk_substs_trait(ty, &[])
2521 let predicates = tcx.predicates_of(self.did).predicates;
2522 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2532 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2536 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2541 impl<'tcx> FieldDef {
2542 /// Returns the type of this field. The `subst` is typically obtained
2543 /// via the second field of `TyKind::AdtDef`.
2544 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2545 tcx.type_of(self.did).subst(tcx, subst)
2549 /// Represents the various closure traits in the language. This
2550 /// will determine the type of the environment (`self`, in the
2551 /// desugaring) argument that the closure expects.
2553 /// You can get the environment type of a closure using
2554 /// `tcx.closure_env_ty()`.
2555 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2556 RustcEncodable, RustcDecodable, HashStable)]
2557 pub enum ClosureKind {
2558 // Warning: Ordering is significant here! The ordering is chosen
2559 // because the trait Fn is a subtrait of FnMut and so in turn, and
2560 // hence we order it so that Fn < FnMut < FnOnce.
2566 impl<'tcx> ClosureKind {
2567 // This is the initial value used when doing upvar inference.
2568 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2570 pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
2572 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem, None),
2573 ClosureKind::FnMut => {
2574 tcx.require_lang_item(FnMutTraitLangItem, None)
2576 ClosureKind::FnOnce => {
2577 tcx.require_lang_item(FnOnceTraitLangItem, None)
2582 /// Returns `true` if this a type that impls this closure kind
2583 /// must also implement `other`.
2584 pub fn extends(self, other: ty::ClosureKind) -> bool {
2585 match (self, other) {
2586 (ClosureKind::Fn, ClosureKind::Fn) => true,
2587 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2588 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2589 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2590 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2591 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2596 /// Returns the representative scalar type for this closure kind.
2597 /// See `TyS::to_opt_closure_kind` for more details.
2598 pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
2600 ty::ClosureKind::Fn => tcx.types.i8,
2601 ty::ClosureKind::FnMut => tcx.types.i16,
2602 ty::ClosureKind::FnOnce => tcx.types.i32,
2607 impl<'tcx> TyS<'tcx> {
2608 /// Iterator that walks `self` and any types reachable from
2609 /// `self`, in depth-first order. Note that just walks the types
2610 /// that appear in `self`, it does not descend into the fields of
2611 /// structs or variants. For example:
2614 /// isize => { isize }
2615 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2616 /// [isize] => { [isize], isize }
2618 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2619 TypeWalker::new(self)
2622 /// Iterator that walks the immediate children of `self`. Hence
2623 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2624 /// (but not `i32`, like `walk`).
2625 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2626 walk::walk_shallow(self)
2629 /// Walks `ty` and any types appearing within `ty`, invoking the
2630 /// callback `f` on each type. If the callback returns `false`, then the
2631 /// children of the current type are ignored.
2633 /// Note: prefer `ty.walk()` where possible.
2634 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2635 where F: FnMut(Ty<'tcx>) -> bool
2637 let mut walker = self.walk();
2638 while let Some(ty) = walker.next() {
2640 walker.skip_current_subtree();
2647 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2649 hir::Mutability::Mutable => MutBorrow,
2650 hir::Mutability::Immutable => ImmBorrow,
2654 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2655 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2656 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2658 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2660 MutBorrow => hir::Mutability::Mutable,
2661 ImmBorrow => hir::Mutability::Immutable,
2663 // We have no type corresponding to a unique imm borrow, so
2664 // use `&mut`. It gives all the capabilities of an `&uniq`
2665 // and hence is a safe "over approximation".
2666 UniqueImmBorrow => hir::Mutability::Mutable,
2670 pub fn to_user_str(&self) -> &'static str {
2672 MutBorrow => "mutable",
2673 ImmBorrow => "immutable",
2674 UniqueImmBorrow => "uniquely immutable",
2679 #[derive(Debug, Clone)]
2680 pub enum Attributes<'tcx> {
2681 Owned(Lrc<[ast::Attribute]>),
2682 Borrowed(&'tcx [ast::Attribute]),
2685 impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
2686 type Target = [ast::Attribute];
2688 fn deref(&self) -> &[ast::Attribute] {
2690 &Attributes::Owned(ref data) => &data,
2691 &Attributes::Borrowed(data) => data
2696 #[derive(Debug, PartialEq, Eq)]
2697 pub enum ImplOverlapKind {
2698 /// These impls are always allowed to overlap.
2700 /// These impls are allowed to overlap, but that raises
2701 /// an issue #33140 future-compatibility warning.
2703 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2704 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2706 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2707 /// that difference, making what reduces to the following set of impls:
2711 /// impl Trait for dyn Send + Sync {}
2712 /// impl Trait for dyn Sync + Send {}
2715 /// Obviously, once we made these types be identical, that code causes a coherence
2716 /// error and a fairly big headache for us. However, luckily for us, the trait
2717 /// `Trait` used in this case is basically a marker trait, and therefore having
2718 /// overlapping impls for it is sound.
2720 /// To handle this, we basically regard the trait as a marker trait, with an additional
2721 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2722 /// it has the following restrictions:
2724 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2726 /// 2. The trait-ref of both impls must be equal.
2727 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2729 /// 4. Neither of the impls can have any where-clauses.
2731 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2735 impl<'tcx> TyCtxt<'tcx> {
2736 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
2737 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2740 /// Returns an iterator of the `DefId`s for all body-owners in this
2741 /// crate. If you would prefer to iterate over the bodies
2742 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2743 pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
2747 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2750 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2751 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2752 f(self.hir().body_owner_def_id(body_id))
2756 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
2757 self.associated_items(id)
2758 .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
2762 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2763 self.associated_items(did).any(|item| {
2764 item.relevant_for_never()
2768 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
2769 self.hir().as_local_hir_id(def_id).and_then(|hir_id| self.hir().get(hir_id).ident())
2772 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
2773 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2774 match self.hir().get(hir_id) {
2775 Node::TraitItem(_) | Node::ImplItem(_) => true,
2779 match self.def_kind(def_id).expect("no def for `DefId`") {
2782 | DefKind::AssocTy => true,
2787 if is_associated_item {
2788 Some(self.associated_item(def_id))
2794 fn associated_item_from_trait_item_ref(self,
2795 parent_def_id: DefId,
2796 parent_vis: &hir::Visibility,
2797 trait_item_ref: &hir::TraitItemRef)
2799 let def_id = self.hir().local_def_id(trait_item_ref.id.hir_id);
2800 let (kind, has_self) = match trait_item_ref.kind {
2801 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2802 hir::AssocItemKind::Method { has_self } => {
2803 (ty::AssocKind::Method, has_self)
2805 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2806 hir::AssocItemKind::OpaqueTy => bug!("only impls can have opaque types"),
2810 ident: trait_item_ref.ident,
2812 // Visibility of trait items is inherited from their traits.
2813 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2814 defaultness: trait_item_ref.defaultness,
2816 container: TraitContainer(parent_def_id),
2817 method_has_self_argument: has_self
2821 fn associated_item_from_impl_item_ref(self,
2822 parent_def_id: DefId,
2823 impl_item_ref: &hir::ImplItemRef)
2825 let def_id = self.hir().local_def_id(impl_item_ref.id.hir_id);
2826 let (kind, has_self) = match impl_item_ref.kind {
2827 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2828 hir::AssocItemKind::Method { has_self } => {
2829 (ty::AssocKind::Method, has_self)
2831 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2832 hir::AssocItemKind::OpaqueTy => (ty::AssocKind::OpaqueTy, false),
2836 ident: impl_item_ref.ident,
2838 // Visibility of trait impl items doesn't matter.
2839 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2840 defaultness: impl_item_ref.defaultness,
2842 container: ImplContainer(parent_def_id),
2843 method_has_self_argument: has_self
2847 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2848 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2851 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2852 variant.fields.iter().position(|field| {
2853 self.hygienic_eq(ident, field.ident, variant.def_id)
2857 pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
2858 // Ideally, we would use `-> impl Iterator` here, but it falls
2859 // afoul of the conservative "capture [restrictions]" we put
2860 // in place, so we use a hand-written iterator.
2862 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2863 AssocItemsIterator {
2865 def_ids: self.associated_item_def_ids(def_id),
2870 /// Returns `true` if the impls are the same polarity and the trait either
2871 /// has no items or is annotated #[marker] and prevents item overrides.
2872 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2873 -> Option<ImplOverlapKind>
2875 // If either trait impl references an error, they're allowed to overlap,
2876 // as one of them essentially doesn't exist.
2877 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error()) ||
2878 self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error()) {
2879 return Some(ImplOverlapKind::Permitted);
2882 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2883 (ImplPolarity::Reservation, _) |
2884 (_, ImplPolarity::Reservation) => {
2885 // `#[rustc_reservation_impl]` impls don't overlap with anything
2886 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2888 return Some(ImplOverlapKind::Permitted);
2890 (ImplPolarity::Positive, ImplPolarity::Negative) |
2891 (ImplPolarity::Negative, ImplPolarity::Positive) => {
2892 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2893 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2897 (ImplPolarity::Positive, ImplPolarity::Positive) |
2898 (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2901 let is_marker_overlap = if self.features().overlapping_marker_traits {
2902 let trait1_is_empty = self.impl_trait_ref(def_id1)
2903 .map_or(false, |trait_ref| {
2904 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2906 let trait2_is_empty = self.impl_trait_ref(def_id2)
2907 .map_or(false, |trait_ref| {
2908 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2910 trait1_is_empty && trait2_is_empty
2912 let is_marker_impl = |def_id: DefId| -> bool {
2913 let trait_ref = self.impl_trait_ref(def_id);
2914 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2916 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2920 if is_marker_overlap {
2921 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2923 Some(ImplOverlapKind::Permitted)
2925 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2926 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2927 if self_ty1 == self_ty2 {
2928 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2930 return Some(ImplOverlapKind::Issue33140);
2932 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2933 def_id1, def_id2, self_ty1, self_ty2);
2938 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2944 /// Returns `ty::VariantDef` if `res` refers to a struct,
2945 /// or variant or their constructors, panics otherwise.
2946 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2948 Res::Def(DefKind::Variant, did) => {
2949 let enum_did = self.parent(did).unwrap();
2950 self.adt_def(enum_did).variant_with_id(did)
2952 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
2953 self.adt_def(did).non_enum_variant()
2955 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2956 let variant_did = self.parent(variant_ctor_did).unwrap();
2957 let enum_did = self.parent(variant_did).unwrap();
2958 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2960 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2961 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2962 self.adt_def(struct_did).non_enum_variant()
2964 _ => bug!("expect_variant_res used with unexpected res {:?}", res)
2968 pub fn item_name(self, id: DefId) -> Symbol {
2969 if id.index == CRATE_DEF_INDEX {
2970 self.original_crate_name(id.krate)
2972 let def_key = self.def_key(id);
2973 match def_key.disambiguated_data.data {
2974 // The name of a constructor is that of its parent.
2975 hir_map::DefPathData::Ctor =>
2976 self.item_name(DefId {
2978 index: def_key.parent.unwrap()
2980 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2981 bug!("item_name: no name for {:?}", self.def_path(id));
2987 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2988 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> ReadOnlyBodyCache<'tcx, 'tcx> {
2990 ty::InstanceDef::Item(did) => {
2991 self.optimized_mir(did).unwrap_read_only()
2993 ty::InstanceDef::VtableShim(..) |
2994 ty::InstanceDef::ReifyShim(..) |
2995 ty::InstanceDef::Intrinsic(..) |
2996 ty::InstanceDef::FnPtrShim(..) |
2997 ty::InstanceDef::Virtual(..) |
2998 ty::InstanceDef::ClosureOnceShim { .. } |
2999 ty::InstanceDef::DropGlue(..) |
3000 ty::InstanceDef::CloneShim(..) => {
3001 self.mir_shims(instance).unwrap_read_only()
3006 /// Gets the attributes of a definition.
3007 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
3008 if let Some(id) = self.hir().as_local_hir_id(did) {
3009 Attributes::Borrowed(self.hir().attrs(id))
3011 Attributes::Owned(self.item_attrs(did))
3015 /// Determines whether an item is annotated with an attribute.
3016 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
3017 attr::contains_name(&self.get_attrs(did), attr)
3020 /// Returns `true` if this is an `auto trait`.
3021 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3022 self.trait_def(trait_def_id).has_auto_impl
3025 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3026 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3029 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3030 /// If it implements no trait, returns `None`.
3031 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3032 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3035 /// If the given defid describes a method belonging to an impl, returns the
3036 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3037 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3038 let item = if def_id.krate != LOCAL_CRATE {
3039 if let Some(DefKind::Method) = self.def_kind(def_id) {
3040 Some(self.associated_item(def_id))
3045 self.opt_associated_item(def_id)
3048 item.and_then(|trait_item|
3049 match trait_item.container {
3050 TraitContainer(_) => None,
3051 ImplContainer(def_id) => Some(def_id),
3056 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3057 /// with the name of the crate containing the impl.
3058 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3059 if impl_did.is_local() {
3060 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3061 Ok(self.hir().span(hir_id))
3063 Err(self.crate_name(impl_did.krate))
3067 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3068 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3069 /// definition's parent/scope to perform comparison.
3070 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3071 // We could use `Ident::eq` here, but we deliberately don't. The name
3072 // comparison fails frequently, and we want to avoid the expensive
3073 // `modern()` calls required for the span comparison whenever possible.
3074 use_name.name == def_name.name &&
3075 use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
3076 self.expansion_that_defined(def_parent_def_id))
3079 fn expansion_that_defined(self, scope: DefId) -> ExpnId {
3081 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3082 _ => ExpnId::root(),
3086 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
3087 ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
3091 pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
3093 let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
3094 Some(actual_expansion) =>
3095 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3096 None => self.hir().get_module_parent(block),
3103 pub struct AssocItemsIterator<'tcx> {
3105 def_ids: &'tcx [DefId],
3109 impl Iterator for AssocItemsIterator<'_> {
3110 type Item = AssocItem;
3112 fn next(&mut self) -> Option<AssocItem> {
3113 let def_id = self.def_ids.get(self.next_index)?;
3114 self.next_index += 1;
3115 Some(self.tcx.associated_item(*def_id))
3119 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
3120 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3121 let parent_id = tcx.hir().get_parent_item(id);
3122 let parent_def_id = tcx.hir().local_def_id(parent_id);
3123 let parent_item = tcx.hir().expect_item(parent_id);
3124 match parent_item.kind {
3125 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3126 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3127 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3129 debug_assert_eq!(assoc_item.def_id, def_id);
3134 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3135 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3136 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3139 debug_assert_eq!(assoc_item.def_id, def_id);
3147 span_bug!(parent_item.span,
3148 "unexpected parent of trait or impl item or item not found: {:?}",
3152 #[derive(Clone, HashStable)]
3153 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3155 /// Calculates the `Sized` constraint.
3157 /// In fact, there are only a few options for the types in the constraint:
3158 /// - an obviously-unsized type
3159 /// - a type parameter or projection whose Sizedness can't be known
3160 /// - a tuple of type parameters or projections, if there are multiple
3162 /// - a Error, if a type contained itself. The representability
3163 /// check should catch this case.
3164 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
3165 let def = tcx.adt_def(def_id);
3167 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3170 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3173 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3175 AdtSizedConstraint(result)
3178 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
3179 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3180 let item = tcx.hir().expect_item(id);
3182 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3183 tcx.arena.alloc_from_iter(
3184 trait_item_refs.iter()
3185 .map(|trait_item_ref| trait_item_ref.id)
3186 .map(|id| tcx.hir().local_def_id(id.hir_id))
3189 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3190 tcx.arena.alloc_from_iter(
3191 impl_item_refs.iter()
3192 .map(|impl_item_ref| impl_item_ref.id)
3193 .map(|id| tcx.hir().local_def_id(id.hir_id))
3196 hir::ItemKind::TraitAlias(..) => &[],
3197 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3201 fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
3202 tcx.hir().span_if_local(def_id).unwrap()
3205 /// If the given `DefId` describes an item belonging to a trait,
3206 /// returns the `DefId` of the trait that the trait item belongs to;
3207 /// otherwise, returns `None`.
3208 fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3209 tcx.opt_associated_item(def_id)
3210 .and_then(|associated_item| {
3211 match associated_item.container {
3212 TraitContainer(def_id) => Some(def_id),
3213 ImplContainer(_) => None
3218 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3219 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3220 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3221 if let Node::Item(item) = tcx.hir().get(hir_id) {
3222 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
3223 return opaque_ty.impl_trait_fn;
3230 /// See `ParamEnv` struct definition for details.
3231 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
3232 // The param_env of an impl Trait type is its defining function's param_env
3233 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3234 return param_env(tcx, parent);
3236 // Compute the bounds on Self and the type parameters.
3238 let InstantiatedPredicates { predicates } =
3239 tcx.predicates_of(def_id).instantiate_identity(tcx);
3241 // Finally, we have to normalize the bounds in the environment, in
3242 // case they contain any associated type projections. This process
3243 // can yield errors if the put in illegal associated types, like
3244 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3245 // report these errors right here; this doesn't actually feel
3246 // right to me, because constructing the environment feels like a
3247 // kind of a "idempotent" action, but I'm not sure where would be
3248 // a better place. In practice, we construct environments for
3249 // every fn once during type checking, and we'll abort if there
3250 // are any errors at that point, so after type checking you can be
3251 // sure that this will succeed without errors anyway.
3253 let unnormalized_env = ty::ParamEnv::new(
3254 tcx.intern_predicates(&predicates),
3255 traits::Reveal::UserFacing,
3256 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3259 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3260 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
3262 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3263 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3266 fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
3267 assert_eq!(crate_num, LOCAL_CRATE);
3268 tcx.sess.local_crate_disambiguator()
3271 fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
3272 assert_eq!(crate_num, LOCAL_CRATE);
3273 tcx.crate_name.clone()
3276 fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
3277 assert_eq!(crate_num, LOCAL_CRATE);
3278 tcx.hir().crate_hash
3281 fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
3282 match instance_def {
3283 InstanceDef::Item(..) |
3284 InstanceDef::DropGlue(..) => {
3285 let mir = tcx.instance_mir(instance_def);
3286 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3288 // Estimate the size of other compiler-generated shims to be 1.
3293 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3295 /// See [`ImplOverlapKind::Issue33140`] for more details.
3296 fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
3297 debug!("issue33140_self_ty({:?})", def_id);
3299 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3300 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3303 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3305 let is_marker_like =
3306 tcx.impl_polarity(def_id) == ty::ImplPolarity::Positive &&
3307 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3309 // Check whether these impls would be ok for a marker trait.
3310 if !is_marker_like {
3311 debug!("issue33140_self_ty - not marker-like!");
3315 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3316 if trait_ref.substs.len() != 1 {
3317 debug!("issue33140_self_ty - impl has substs!");
3321 let predicates = tcx.predicates_of(def_id);
3322 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3323 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3327 let self_ty = trait_ref.self_ty();
3328 let self_ty_matches = match self_ty.kind {
3329 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3333 if self_ty_matches {
3334 debug!("issue33140_self_ty - MATCHES!");
3337 debug!("issue33140_self_ty - non-matching self type");
3342 /// Check if a function is async.
3343 fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
3344 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap_or_else(|| {
3345 bug!("asyncness: expected local `DefId`, got `{:?}`", def_id)
3348 let node = tcx.hir().get(hir_id);
3350 let fn_like = hir::map::blocks::FnLikeNode::from_node(node).unwrap_or_else(|| {
3351 bug!("asyncness: expected fn-like node but got `{:?}`", def_id);
3357 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3358 context::provide(providers);
3359 erase_regions::provide(providers);
3360 layout::provide(providers);
3361 util::provide(providers);
3362 constness::provide(providers);
3363 *providers = ty::query::Providers {
3366 associated_item_def_ids,
3367 adt_sized_constraint,
3371 crate_disambiguator,
3372 original_crate_name,
3374 trait_impls_of: trait_def::trait_impls_of_provider,
3375 instance_def_size_estimate,
3381 /// A map for the local crate mapping each type to a vector of its
3382 /// inherent impls. This is not meant to be used outside of coherence;
3383 /// rather, you should request the vector for a specific type via
3384 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3385 /// (constructing this map requires touching the entire crate).
3386 #[derive(Clone, Debug, Default, HashStable)]
3387 pub struct CrateInherentImpls {
3388 pub inherent_impls: DefIdMap<Vec<DefId>>,
3391 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
3392 pub struct SymbolName {
3393 // FIXME: we don't rely on interning or equality here - better have
3394 // this be a `&'tcx str`.
3399 pub fn new(name: &str) -> SymbolName {
3401 name: Symbol::intern(name)
3406 impl PartialOrd for SymbolName {
3407 fn partial_cmp(&self, other: &SymbolName) -> Option<Ordering> {
3408 self.name.as_str().partial_cmp(&other.name.as_str())
3412 /// Ordering must use the chars to ensure reproducible builds.
3413 impl Ord for SymbolName {
3414 fn cmp(&self, other: &SymbolName) -> Ordering {
3415 self.name.as_str().cmp(&other.name.as_str())
3419 impl fmt::Display for SymbolName {
3420 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3421 fmt::Display::fmt(&self.name, fmt)
3425 impl fmt::Debug for SymbolName {
3426 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3427 fmt::Display::fmt(&self.name, fmt)