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;
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};
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::*;
75 pub use self::binding::BindingMode;
76 pub use self::binding::BindingMode::*;
78 pub use self::context::{TyCtxt, FreeRegionInfo, AllArenas, tls, keep_local};
79 pub use self::context::{Lift, GeneratorInteriorTypeCause, TypeckTables, CtxtInterners, GlobalCtxt};
80 pub use self::context::{
81 UserTypeAnnotationIndex, UserType, CanonicalUserType,
82 CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
85 pub use self::instance::{Instance, InstanceDef};
87 pub use self::structural_match::search_for_structural_match_violation;
88 pub use self::structural_match::type_marked_structural;
89 pub use self::structural_match::NonStructuralMatchTy;
91 pub use self::trait_def::TraitDef;
93 pub use self::query::queries;
106 pub mod inhabitedness;
122 mod structural_impls;
123 mod structural_match;
128 pub struct ResolverOutputs {
129 pub definitions: hir_map::Definitions,
130 pub cstore: Box<CrateStoreDyn>,
131 pub extern_crate_map: NodeMap<CrateNum>,
132 pub trait_map: TraitMap,
133 pub maybe_unused_trait_imports: NodeSet,
134 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
135 pub export_map: ExportMap<NodeId>,
136 pub glob_map: GlobMap,
137 /// Extern prelude entries. The value is `true` if the entry was introduced
138 /// via `extern crate` item and not `--extern` option or compiler built-in.
139 pub extern_prelude: FxHashMap<Name, bool>,
142 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
143 pub enum AssocItemContainer {
144 TraitContainer(DefId),
145 ImplContainer(DefId),
148 impl AssocItemContainer {
149 /// Asserts that this is the `DefId` of an associated item declared
150 /// in a trait, and returns the trait `DefId`.
151 pub fn assert_trait(&self) -> DefId {
153 TraitContainer(id) => id,
154 _ => bug!("associated item has wrong container type: {:?}", self)
158 pub fn id(&self) -> DefId {
160 TraitContainer(id) => id,
161 ImplContainer(id) => id,
166 /// The "header" of an impl is everything outside the body: a Self type, a trait
167 /// ref (in the case of a trait impl), and a set of predicates (from the
168 /// bounds / where-clauses).
169 #[derive(Clone, Debug)]
170 pub struct ImplHeader<'tcx> {
171 pub impl_def_id: DefId,
172 pub self_ty: Ty<'tcx>,
173 pub trait_ref: Option<TraitRef<'tcx>>,
174 pub predicates: Vec<Predicate<'tcx>>,
177 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
178 pub enum ImplPolarity {
179 /// `impl Trait for Type`
181 /// `impl !Trait for Type`
183 /// `#[rustc_reservation_impl] impl Trait for Type`
185 /// This is a "stability hack", not a real Rust feature.
186 /// See #64631 for details.
190 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
191 pub struct AssocItem {
193 #[stable_hasher(project(name))]
197 pub defaultness: hir::Defaultness,
198 pub container: AssocItemContainer,
200 /// Whether this is a method with an explicit self
201 /// as its first argument, allowing method calls.
202 pub method_has_self_argument: bool,
205 #[derive(Copy, Clone, PartialEq, Debug, HashStable)]
214 pub fn def_kind(&self) -> DefKind {
216 AssocKind::Const => DefKind::AssocConst,
217 AssocKind::Method => DefKind::Method,
218 AssocKind::Type => DefKind::AssocTy,
219 AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
223 /// Tests whether the associated item admits a non-trivial implementation
225 pub fn relevant_for_never(&self) -> bool {
227 AssocKind::OpaqueTy |
229 AssocKind::Type => true,
230 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
231 AssocKind::Method => !self.method_has_self_argument,
235 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
237 ty::AssocKind::Method => {
238 // We skip the binder here because the binder would deanonymize all
239 // late-bound regions, and we don't want method signatures to show up
240 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
241 // regions just fine, showing `fn(&MyType)`.
242 tcx.fn_sig(self.def_id).skip_binder().to_string()
244 ty::AssocKind::Type => format!("type {};", self.ident),
245 // FIXME(type_alias_impl_trait): we should print bounds here too.
246 ty::AssocKind::OpaqueTy => format!("type {};", self.ident),
247 ty::AssocKind::Const => {
248 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
254 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
255 pub enum Visibility {
256 /// Visible everywhere (including in other crates).
258 /// Visible only in the given crate-local module.
260 /// Not visible anywhere in the local crate. This is the visibility of private external items.
264 pub trait DefIdTree: Copy {
265 fn parent(self, id: DefId) -> Option<DefId>;
267 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
268 if descendant.krate != ancestor.krate {
272 while descendant != ancestor {
273 match self.parent(descendant) {
274 Some(parent) => descendant = parent,
275 None => return false,
282 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
283 fn parent(self, id: DefId) -> Option<DefId> {
284 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
289 pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
290 match visibility.node {
291 hir::VisibilityKind::Public => Visibility::Public,
292 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
293 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
294 // If there is no resolution, `resolve` will have already reported an error, so
295 // assume that the visibility is public to avoid reporting more privacy errors.
296 Res::Err => Visibility::Public,
297 def => Visibility::Restricted(def.def_id()),
299 hir::VisibilityKind::Inherited => {
300 Visibility::Restricted(tcx.hir().get_module_parent(id))
305 /// Returns `true` if an item with this visibility is accessible from the given block.
306 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
307 let restriction = match self {
308 // Public items are visible everywhere.
309 Visibility::Public => return true,
310 // Private items from other crates are visible nowhere.
311 Visibility::Invisible => return false,
312 // Restricted items are visible in an arbitrary local module.
313 Visibility::Restricted(other) if other.krate != module.krate => return false,
314 Visibility::Restricted(module) => module,
317 tree.is_descendant_of(module, restriction)
320 /// Returns `true` if this visibility is at least as accessible as the given visibility
321 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
322 let vis_restriction = match vis {
323 Visibility::Public => return self == Visibility::Public,
324 Visibility::Invisible => return true,
325 Visibility::Restricted(module) => module,
328 self.is_accessible_from(vis_restriction, tree)
331 // Returns `true` if this item is visible anywhere in the local crate.
332 pub fn is_visible_locally(self) -> bool {
334 Visibility::Public => true,
335 Visibility::Restricted(def_id) => def_id.is_local(),
336 Visibility::Invisible => false,
341 #[derive(Copy, Clone, PartialEq, RustcDecodable, RustcEncodable, HashStable)]
343 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
344 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
345 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
346 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
349 /// The crate variances map is computed during typeck and contains the
350 /// variance of every item in the local crate. You should not use it
351 /// directly, because to do so will make your pass dependent on the
352 /// HIR of every item in the local crate. Instead, use
353 /// `tcx.variances_of()` to get the variance for a *particular*
355 #[derive(HashStable)]
356 pub struct CrateVariancesMap<'tcx> {
357 /// For each item with generics, maps to a vector of the variance
358 /// of its generics. If an item has no generics, it will have no
360 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
364 /// `a.xform(b)` combines the variance of a context with the
365 /// variance of a type with the following meaning. If we are in a
366 /// context with variance `a`, and we encounter a type argument in
367 /// a position with variance `b`, then `a.xform(b)` is the new
368 /// variance with which the argument appears.
374 /// Here, the "ambient" variance starts as covariant. `*mut T` is
375 /// invariant with respect to `T`, so the variance in which the
376 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
377 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
378 /// respect to its type argument `T`, and hence the variance of
379 /// the `i32` here is `Invariant.xform(Covariant)`, which results
380 /// (again) in `Invariant`.
384 /// fn(*const Vec<i32>, *mut Vec<i32)
386 /// The ambient variance is covariant. A `fn` type is
387 /// contravariant with respect to its parameters, so the variance
388 /// within which both pointer types appear is
389 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
390 /// T` is covariant with respect to `T`, so the variance within
391 /// which the first `Vec<i32>` appears is
392 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
393 /// is true for its `i32` argument. In the `*mut T` case, the
394 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
395 /// and hence the outermost type is `Invariant` with respect to
396 /// `Vec<i32>` (and its `i32` argument).
398 /// Source: Figure 1 of "Taming the Wildcards:
399 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
400 pub fn xform(self, v: ty::Variance) -> ty::Variance {
402 // Figure 1, column 1.
403 (ty::Covariant, ty::Covariant) => ty::Covariant,
404 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
405 (ty::Covariant, ty::Invariant) => ty::Invariant,
406 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
408 // Figure 1, column 2.
409 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
410 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
411 (ty::Contravariant, ty::Invariant) => ty::Invariant,
412 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
414 // Figure 1, column 3.
415 (ty::Invariant, _) => ty::Invariant,
417 // Figure 1, column 4.
418 (ty::Bivariant, _) => ty::Bivariant,
423 // Contains information needed to resolve types and (in the future) look up
424 // the types of AST nodes.
425 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
426 pub struct CReaderCacheKey {
431 // Flags that we track on types. These flags are propagated upwards
432 // through the type during type construction, so that we can quickly
433 // check whether the type has various kinds of types in it without
434 // recursing over the type itself.
436 pub struct TypeFlags: u32 {
437 const HAS_PARAMS = 1 << 0;
438 const HAS_TY_INFER = 1 << 1;
439 const HAS_RE_INFER = 1 << 2;
440 const HAS_RE_PLACEHOLDER = 1 << 3;
442 /// Does this have any `ReEarlyBound` regions? Used to
443 /// determine whether substitition is required, since those
444 /// represent regions that are bound in a `ty::Generics` and
445 /// hence may be substituted.
446 const HAS_RE_EARLY_BOUND = 1 << 4;
448 /// Does this have any region that "appears free" in the type?
449 /// Basically anything but `ReLateBound` and `ReErased`.
450 const HAS_FREE_REGIONS = 1 << 5;
452 /// Is an error type reachable?
453 const HAS_TY_ERR = 1 << 6;
454 const HAS_PROJECTION = 1 << 7;
456 // FIXME: Rename this to the actual property since it's used for generators too
457 const HAS_TY_CLOSURE = 1 << 8;
459 /// `true` if there are "names" of types and regions and so forth
460 /// that are local to a particular fn
461 const HAS_FREE_LOCAL_NAMES = 1 << 9;
463 /// Present if the type belongs in a local type context.
464 /// Only set for Infer other than Fresh.
465 const KEEP_IN_LOCAL_TCX = 1 << 10;
467 /// Does this have any `ReLateBound` regions? Used to check
468 /// if a global bound is safe to evaluate.
469 const HAS_RE_LATE_BOUND = 1 << 11;
471 const HAS_TY_PLACEHOLDER = 1 << 12;
473 const HAS_CT_INFER = 1 << 13;
474 const HAS_CT_PLACEHOLDER = 1 << 14;
476 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
477 TypeFlags::HAS_RE_EARLY_BOUND.bits;
479 /// Flags representing the nominal content of a type,
480 /// computed by FlagsComputation. If you add a new nominal
481 /// flag, it should be added here too.
482 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
483 TypeFlags::HAS_TY_INFER.bits |
484 TypeFlags::HAS_RE_INFER.bits |
485 TypeFlags::HAS_RE_PLACEHOLDER.bits |
486 TypeFlags::HAS_RE_EARLY_BOUND.bits |
487 TypeFlags::HAS_FREE_REGIONS.bits |
488 TypeFlags::HAS_TY_ERR.bits |
489 TypeFlags::HAS_PROJECTION.bits |
490 TypeFlags::HAS_TY_CLOSURE.bits |
491 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
492 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
493 TypeFlags::HAS_RE_LATE_BOUND.bits |
494 TypeFlags::HAS_TY_PLACEHOLDER.bits |
495 TypeFlags::HAS_CT_INFER.bits |
496 TypeFlags::HAS_CT_PLACEHOLDER.bits;
500 #[allow(rustc::usage_of_ty_tykind)]
501 pub struct TyS<'tcx> {
502 pub kind: TyKind<'tcx>,
503 pub flags: TypeFlags,
505 /// This is a kind of confusing thing: it stores the smallest
508 /// (a) the binder itself captures nothing but
509 /// (b) all the late-bound things within the type are captured
510 /// by some sub-binder.
512 /// So, for a type without any late-bound things, like `u32`, this
513 /// will be *innermost*, because that is the innermost binder that
514 /// captures nothing. But for a type `&'D u32`, where `'D` is a
515 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
516 /// -- the binder itself does not capture `D`, but `D` is captured
517 /// by an inner binder.
519 /// We call this concept an "exclusive" binder `D` because all
520 /// De Bruijn indices within the type are contained within `0..D`
522 outer_exclusive_binder: ty::DebruijnIndex,
525 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
526 #[cfg(target_arch = "x86_64")]
527 static_assert_size!(TyS<'_>, 32);
529 impl<'tcx> Ord for TyS<'tcx> {
530 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
531 self.kind.cmp(&other.kind)
535 impl<'tcx> PartialOrd for TyS<'tcx> {
536 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
537 Some(self.kind.cmp(&other.kind))
541 impl<'tcx> PartialEq for TyS<'tcx> {
543 fn eq(&self, other: &TyS<'tcx>) -> bool {
547 impl<'tcx> Eq for TyS<'tcx> {}
549 impl<'tcx> Hash for TyS<'tcx> {
550 fn hash<H: Hasher>(&self, s: &mut H) {
551 (self as *const TyS<'_>).hash(s)
555 impl<'tcx> TyS<'tcx> {
556 pub fn is_primitive_ty(&self) -> bool {
563 Infer(InferTy::IntVar(_)) |
564 Infer(InferTy::FloatVar(_)) |
565 Infer(InferTy::FreshIntTy(_)) |
566 Infer(InferTy::FreshFloatTy(_)) => true,
567 Ref(_, x, _) => x.is_primitive_ty(),
572 pub fn is_suggestable(&self) -> bool {
580 Projection(..) => false,
586 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
587 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
591 // The other fields just provide fast access to information that is
592 // also contained in `kind`, so no need to hash them.
595 outer_exclusive_binder: _,
598 kind.hash_stable(hcx, hasher);
602 #[rustc_diagnostic_item = "Ty"]
603 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
605 impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {}
606 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {}
608 pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
611 /// A dummy type used to force `List` to be unsized while not requiring references to it be wide
613 type OpaqueListContents;
616 /// A wrapper for slices with the additional invariant
617 /// that the slice is interned and no other slice with
618 /// the same contents can exist in the same context.
619 /// This means we can use pointer for both
620 /// equality comparisons and hashing.
621 /// Note: `Slice` was already taken by the `Ty`.
626 opaque: OpaqueListContents,
629 unsafe impl<T: Sync> Sync for List<T> {}
631 impl<T: Copy> List<T> {
633 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
634 assert!(!mem::needs_drop::<T>());
635 assert!(mem::size_of::<T>() != 0);
636 assert!(slice.len() != 0);
638 // Align up the size of the len (usize) field
639 let align = mem::align_of::<T>();
640 let align_mask = align - 1;
641 let offset = mem::size_of::<usize>();
642 let offset = (offset + align_mask) & !align_mask;
644 let size = offset + slice.len() * mem::size_of::<T>();
646 let mem = arena.alloc_raw(
648 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
650 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
652 result.len = slice.len();
654 // Write the elements
655 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
656 arena_slice.copy_from_slice(slice);
663 impl<T: fmt::Debug> fmt::Debug for List<T> {
664 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
669 impl<T: Encodable> Encodable for List<T> {
671 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
676 impl<T> Ord for List<T> where T: Ord {
677 fn cmp(&self, other: &List<T>) -> Ordering {
678 if self == other { Ordering::Equal } else {
679 <[T] as Ord>::cmp(&**self, &**other)
684 impl<T> PartialOrd for List<T> where T: PartialOrd {
685 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
686 if self == other { Some(Ordering::Equal) } else {
687 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
692 impl<T: PartialEq> PartialEq for List<T> {
694 fn eq(&self, other: &List<T>) -> bool {
698 impl<T: Eq> Eq for List<T> {}
700 impl<T> Hash for List<T> {
702 fn hash<H: Hasher>(&self, s: &mut H) {
703 (self as *const List<T>).hash(s)
707 impl<T> Deref for List<T> {
710 fn deref(&self) -> &[T] {
715 impl<T> AsRef<[T]> for List<T> {
717 fn as_ref(&self) -> &[T] {
719 slice::from_raw_parts(self.data.as_ptr(), self.len)
724 impl<'a, T> IntoIterator for &'a List<T> {
726 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
728 fn into_iter(self) -> Self::IntoIter {
733 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
737 pub fn empty<'a>() -> &'a List<T> {
738 #[repr(align(64), C)]
739 struct EmptySlice([u8; 64]);
740 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
741 assert!(mem::align_of::<T>() <= 64);
743 &*(&EMPTY_SLICE as *const _ as *const List<T>)
748 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
749 pub struct UpvarPath {
750 pub hir_id: hir::HirId,
753 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
754 /// the original var ID (that is, the root variable that is referenced
755 /// by the upvar) and the ID of the closure expression.
756 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
758 pub var_path: UpvarPath,
759 pub closure_expr_id: LocalDefId,
762 #[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
763 pub enum BorrowKind {
764 /// Data must be immutable and is aliasable.
767 /// Data must be immutable but not aliasable. This kind of borrow
768 /// cannot currently be expressed by the user and is used only in
769 /// implicit closure bindings. It is needed when the closure
770 /// is borrowing or mutating a mutable referent, e.g.:
772 /// let x: &mut isize = ...;
773 /// let y = || *x += 5;
775 /// If we were to try to translate this closure into a more explicit
776 /// form, we'd encounter an error with the code as written:
778 /// struct Env { x: & &mut isize }
779 /// let x: &mut isize = ...;
780 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
781 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
783 /// This is then illegal because you cannot mutate a `&mut` found
784 /// in an aliasable location. To solve, you'd have to translate with
785 /// an `&mut` borrow:
787 /// struct Env { x: & &mut isize }
788 /// let x: &mut isize = ...;
789 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
790 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
792 /// Now the assignment to `**env.x` is legal, but creating a
793 /// mutable pointer to `x` is not because `x` is not mutable. We
794 /// could fix this by declaring `x` as `let mut x`. This is ok in
795 /// user code, if awkward, but extra weird for closures, since the
796 /// borrow is hidden.
798 /// So we introduce a "unique imm" borrow -- the referent is
799 /// immutable, but not aliasable. This solves the problem. For
800 /// simplicity, we don't give users the way to express this
801 /// borrow, it's just used when translating closures.
804 /// Data is mutable and not aliasable.
808 /// Information describing the capture of an upvar. This is computed
809 /// during `typeck`, specifically by `regionck`.
810 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
811 pub enum UpvarCapture<'tcx> {
812 /// Upvar is captured by value. This is always true when the
813 /// closure is labeled `move`, but can also be true in other cases
814 /// depending on inference.
817 /// Upvar is captured by reference.
818 ByRef(UpvarBorrow<'tcx>),
821 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
822 pub struct UpvarBorrow<'tcx> {
823 /// The kind of borrow: by-ref upvars have access to shared
824 /// immutable borrows, which are not part of the normal language
826 pub kind: BorrowKind,
828 /// Region of the resulting reference.
829 pub region: ty::Region<'tcx>,
832 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
833 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
835 #[derive(Copy, Clone)]
836 pub struct ClosureUpvar<'tcx> {
842 #[derive(Clone, Copy, PartialEq, Eq)]
843 pub enum IntVarValue {
845 UintType(ast::UintTy),
848 #[derive(Clone, Copy, PartialEq, Eq)]
849 pub struct FloatVarValue(pub ast::FloatTy);
851 impl ty::EarlyBoundRegion {
852 pub fn to_bound_region(&self) -> ty::BoundRegion {
853 ty::BoundRegion::BrNamed(self.def_id, self.name)
856 /// Does this early bound region have a name? Early bound regions normally
857 /// always have names except when using anonymous lifetimes (`'_`).
858 pub fn has_name(&self) -> bool {
859 self.name != kw::UnderscoreLifetime
863 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
864 pub enum GenericParamDefKind {
868 object_lifetime_default: ObjectLifetimeDefault,
869 synthetic: Option<hir::SyntheticTyParamKind>,
874 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
875 pub struct GenericParamDef {
880 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
881 /// on generic parameter `'a`/`T`, asserts data behind the parameter
882 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
883 pub pure_wrt_drop: bool,
885 pub kind: GenericParamDefKind,
888 impl GenericParamDef {
889 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
890 if let GenericParamDefKind::Lifetime = self.kind {
891 ty::EarlyBoundRegion {
897 bug!("cannot convert a non-lifetime parameter def to an early bound region")
901 pub fn to_bound_region(&self) -> ty::BoundRegion {
902 if let GenericParamDefKind::Lifetime = self.kind {
903 self.to_early_bound_region_data().to_bound_region()
905 bug!("cannot convert a non-lifetime parameter def to an early bound region")
911 pub struct GenericParamCount {
912 pub lifetimes: usize,
917 /// Information about the formal type/lifetime parameters associated
918 /// with an item or method. Analogous to `hir::Generics`.
920 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
921 /// `Self` (optionally), `Lifetime` params..., `Type` params...
922 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
923 pub struct Generics {
924 pub parent: Option<DefId>,
925 pub parent_count: usize,
926 pub params: Vec<GenericParamDef>,
928 /// Reverse map to the `index` field of each `GenericParamDef`.
929 #[stable_hasher(ignore)]
930 pub param_def_id_to_index: FxHashMap<DefId, u32>,
933 pub has_late_bound_regions: Option<Span>,
936 impl<'tcx> Generics {
937 pub fn count(&self) -> usize {
938 self.parent_count + self.params.len()
941 pub fn own_counts(&self) -> GenericParamCount {
942 // We could cache this as a property of `GenericParamCount`, but
943 // the aim is to refactor this away entirely eventually and the
944 // presence of this method will be a constant reminder.
945 let mut own_counts: GenericParamCount = Default::default();
947 for param in &self.params {
949 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
950 GenericParamDefKind::Type { .. } => own_counts.types += 1,
951 GenericParamDefKind::Const => own_counts.consts += 1,
958 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
959 if self.own_requires_monomorphization() {
963 if let Some(parent_def_id) = self.parent {
964 let parent = tcx.generics_of(parent_def_id);
965 parent.requires_monomorphization(tcx)
971 pub fn own_requires_monomorphization(&self) -> bool {
972 for param in &self.params {
974 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
975 GenericParamDefKind::Lifetime => {}
983 param: &EarlyBoundRegion,
985 ) -> &'tcx GenericParamDef {
986 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
987 let param = &self.params[index as usize];
989 GenericParamDefKind::Lifetime => param,
990 _ => bug!("expected lifetime parameter, but found another generic parameter")
993 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
994 .region_param(param, tcx)
998 /// Returns the `GenericParamDef` associated with this `ParamTy`.
999 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
1000 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
1001 let param = &self.params[index as usize];
1003 GenericParamDefKind::Type { .. } => param,
1004 _ => bug!("expected type parameter, but found another generic parameter")
1007 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
1008 .type_param(param, tcx)
1012 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
1013 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
1014 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
1015 let param = &self.params[index as usize];
1017 GenericParamDefKind::Const => param,
1018 _ => bug!("expected const parameter, but found another generic parameter")
1021 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1022 .const_param(param, tcx)
1027 /// Bounds on generics.
1028 #[derive(Copy, Clone, Default, Debug, RustcEncodable, RustcDecodable, HashStable)]
1029 pub struct GenericPredicates<'tcx> {
1030 pub parent: Option<DefId>,
1031 pub predicates: &'tcx [(Predicate<'tcx>, Span)],
1034 impl<'tcx> GenericPredicates<'tcx> {
1038 substs: SubstsRef<'tcx>,
1039 ) -> InstantiatedPredicates<'tcx> {
1040 let mut instantiated = InstantiatedPredicates::empty();
1041 self.instantiate_into(tcx, &mut instantiated, substs);
1045 pub fn instantiate_own(
1048 substs: SubstsRef<'tcx>,
1049 ) -> InstantiatedPredicates<'tcx> {
1050 InstantiatedPredicates {
1051 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1055 fn instantiate_into(
1058 instantiated: &mut InstantiatedPredicates<'tcx>,
1059 substs: SubstsRef<'tcx>,
1061 if let Some(def_id) = self.parent {
1062 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1064 instantiated.predicates.extend(
1065 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1069 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
1070 let mut instantiated = InstantiatedPredicates::empty();
1071 self.instantiate_identity_into(tcx, &mut instantiated);
1075 fn instantiate_identity_into(
1078 instantiated: &mut InstantiatedPredicates<'tcx>,
1080 if let Some(def_id) = self.parent {
1081 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1083 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1086 pub fn instantiate_supertrait(
1089 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1090 ) -> InstantiatedPredicates<'tcx> {
1091 assert_eq!(self.parent, None);
1092 InstantiatedPredicates {
1093 predicates: self.predicates.iter().map(|(pred, _)| {
1094 pred.subst_supertrait(tcx, poly_trait_ref)
1100 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1101 pub enum Predicate<'tcx> {
1102 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1103 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1104 /// would be the type parameters.
1105 Trait(PolyTraitPredicate<'tcx>),
1108 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1111 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1113 /// `where <T as TraitRef>::Name == X`, approximately.
1114 /// See the `ProjectionPredicate` struct for details.
1115 Projection(PolyProjectionPredicate<'tcx>),
1117 /// No syntax: `T` well-formed.
1118 WellFormed(Ty<'tcx>),
1120 /// Trait must be object-safe.
1123 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1124 /// for some substitutions `...` and `T` being a closure type.
1125 /// Satisfied (or refuted) once we know the closure's kind.
1126 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
1129 Subtype(PolySubtypePredicate<'tcx>),
1131 /// Constant initializer must evaluate successfully.
1132 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1135 /// The crate outlives map is computed during typeck and contains the
1136 /// outlives of every item in the local crate. You should not use it
1137 /// directly, because to do so will make your pass dependent on the
1138 /// HIR of every item in the local crate. Instead, use
1139 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1141 #[derive(HashStable)]
1142 pub struct CratePredicatesMap<'tcx> {
1143 /// For each struct with outlive bounds, maps to a vector of the
1144 /// predicate of its outlive bounds. If an item has no outlives
1145 /// bounds, it will have no entry.
1146 pub predicates: FxHashMap<DefId, &'tcx [(ty::Predicate<'tcx>, Span)]>,
1149 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1150 fn as_ref(&self) -> &Predicate<'tcx> {
1155 impl<'tcx> Predicate<'tcx> {
1156 /// Performs a substitution suitable for going from a
1157 /// poly-trait-ref to supertraits that must hold if that
1158 /// poly-trait-ref holds. This is slightly different from a normal
1159 /// substitution in terms of what happens with bound regions. See
1160 /// lengthy comment below for details.
1161 pub fn subst_supertrait(
1164 trait_ref: &ty::PolyTraitRef<'tcx>,
1165 ) -> ty::Predicate<'tcx> {
1166 // The interaction between HRTB and supertraits is not entirely
1167 // obvious. Let me walk you (and myself) through an example.
1169 // Let's start with an easy case. Consider two traits:
1171 // trait Foo<'a>: Bar<'a,'a> { }
1172 // trait Bar<'b,'c> { }
1174 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1175 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1176 // knew that `Foo<'x>` (for any 'x) then we also know that
1177 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1178 // normal substitution.
1180 // In terms of why this is sound, the idea is that whenever there
1181 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1182 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1183 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1186 // Another example to be careful of is this:
1188 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1189 // trait Bar1<'b,'c> { }
1191 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1192 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1193 // reason is similar to the previous example: any impl of
1194 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1195 // basically we would want to collapse the bound lifetimes from
1196 // the input (`trait_ref`) and the supertraits.
1198 // To achieve this in practice is fairly straightforward. Let's
1199 // consider the more complicated scenario:
1201 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1202 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1203 // where both `'x` and `'b` would have a DB index of 1.
1204 // The substitution from the input trait-ref is therefore going to be
1205 // `'a => 'x` (where `'x` has a DB index of 1).
1206 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1207 // early-bound parameter and `'b' is a late-bound parameter with a
1209 // - If we replace `'a` with `'x` from the input, it too will have
1210 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1211 // just as we wanted.
1213 // There is only one catch. If we just apply the substitution `'a
1214 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1215 // adjust the DB index because we substituting into a binder (it
1216 // tries to be so smart...) resulting in `for<'x> for<'b>
1217 // Bar1<'x,'b>` (we have no syntax for this, so use your
1218 // imagination). Basically the 'x will have DB index of 2 and 'b
1219 // will have DB index of 1. Not quite what we want. So we apply
1220 // the substitution to the *contents* of the trait reference,
1221 // rather than the trait reference itself (put another way, the
1222 // substitution code expects equal binding levels in the values
1223 // from the substitution and the value being substituted into, and
1224 // this trick achieves that).
1226 let substs = &trait_ref.skip_binder().substs;
1228 Predicate::Trait(ref binder) =>
1229 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1230 Predicate::Subtype(ref binder) =>
1231 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1232 Predicate::RegionOutlives(ref binder) =>
1233 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1234 Predicate::TypeOutlives(ref binder) =>
1235 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1236 Predicate::Projection(ref binder) =>
1237 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1238 Predicate::WellFormed(data) =>
1239 Predicate::WellFormed(data.subst(tcx, substs)),
1240 Predicate::ObjectSafe(trait_def_id) =>
1241 Predicate::ObjectSafe(trait_def_id),
1242 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1243 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1244 Predicate::ConstEvaluatable(def_id, const_substs) =>
1245 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1250 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1251 pub struct TraitPredicate<'tcx> {
1252 pub trait_ref: TraitRef<'tcx>
1255 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1257 impl<'tcx> TraitPredicate<'tcx> {
1258 pub fn def_id(&self) -> DefId {
1259 self.trait_ref.def_id
1262 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
1263 self.trait_ref.input_types()
1266 pub fn self_ty(&self) -> Ty<'tcx> {
1267 self.trait_ref.self_ty()
1271 impl<'tcx> PolyTraitPredicate<'tcx> {
1272 pub fn def_id(&self) -> DefId {
1273 // Ok to skip binder since trait `DefId` does not care about regions.
1274 self.skip_binder().def_id()
1278 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1279 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1280 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1281 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1282 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1283 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1284 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1285 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1287 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1288 pub struct SubtypePredicate<'tcx> {
1289 pub a_is_expected: bool,
1293 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1295 /// This kind of predicate has no *direct* correspondent in the
1296 /// syntax, but it roughly corresponds to the syntactic forms:
1298 /// 1. `T: TraitRef<..., Item = Type>`
1299 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1301 /// In particular, form #1 is "desugared" to the combination of a
1302 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1303 /// predicates. Form #2 is a broader form in that it also permits
1304 /// equality between arbitrary types. Processing an instance of
1305 /// Form #2 eventually yields one of these `ProjectionPredicate`
1306 /// instances to normalize the LHS.
1307 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1308 pub struct ProjectionPredicate<'tcx> {
1309 pub projection_ty: ProjectionTy<'tcx>,
1313 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1315 impl<'tcx> PolyProjectionPredicate<'tcx> {
1316 /// Returns the `DefId` of the associated item being projected.
1317 pub fn item_def_id(&self) -> DefId {
1318 self.skip_binder().projection_ty.item_def_id
1322 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_>) -> PolyTraitRef<'tcx> {
1323 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1324 // `self.0.trait_ref` is permitted to have escaping regions.
1325 // This is because here `self` has a `Binder` and so does our
1326 // return value, so we are preserving the number of binding
1328 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1331 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1332 self.map_bound(|predicate| predicate.ty)
1335 /// The `DefId` of the `TraitItem` for the associated type.
1337 /// Note that this is not the `DefId` of the `TraitRef` containing this
1338 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1339 pub fn projection_def_id(&self) -> DefId {
1340 // Ok to skip binder since trait `DefId` does not care about regions.
1341 self.skip_binder().projection_ty.item_def_id
1345 pub trait ToPolyTraitRef<'tcx> {
1346 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1349 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1350 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1351 ty::Binder::dummy(self.clone())
1355 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1356 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1357 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1361 pub trait ToPredicate<'tcx> {
1362 fn to_predicate(&self) -> Predicate<'tcx>;
1365 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1366 fn to_predicate(&self) -> Predicate<'tcx> {
1367 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1368 trait_ref: self.clone()
1373 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1374 fn to_predicate(&self) -> Predicate<'tcx> {
1375 ty::Predicate::Trait(self.to_poly_trait_predicate())
1379 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1380 fn to_predicate(&self) -> Predicate<'tcx> {
1381 Predicate::RegionOutlives(self.clone())
1385 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1386 fn to_predicate(&self) -> Predicate<'tcx> {
1387 Predicate::TypeOutlives(self.clone())
1391 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1392 fn to_predicate(&self) -> Predicate<'tcx> {
1393 Predicate::Projection(self.clone())
1397 // A custom iterator used by `Predicate::walk_tys`.
1398 enum WalkTysIter<'tcx, I, J, K>
1399 where I: Iterator<Item = Ty<'tcx>>,
1400 J: Iterator<Item = Ty<'tcx>>,
1401 K: Iterator<Item = Ty<'tcx>>
1405 Two(Ty<'tcx>, Ty<'tcx>),
1411 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1412 where I: Iterator<Item = Ty<'tcx>>,
1413 J: Iterator<Item = Ty<'tcx>>,
1414 K: Iterator<Item = Ty<'tcx>>
1416 type Item = Ty<'tcx>;
1418 fn next(&mut self) -> Option<Ty<'tcx>> {
1420 WalkTysIter::None => None,
1421 WalkTysIter::One(item) => {
1422 *self = WalkTysIter::None;
1425 WalkTysIter::Two(item1, item2) => {
1426 *self = WalkTysIter::One(item2);
1429 WalkTysIter::Types(ref mut iter) => {
1432 WalkTysIter::InputTypes(ref mut iter) => {
1435 WalkTysIter::ProjectionTypes(ref mut iter) => {
1442 impl<'tcx> Predicate<'tcx> {
1443 /// Iterates over the types in this predicate. Note that in all
1444 /// cases this is skipping over a binder, so late-bound regions
1445 /// with depth 0 are bound by the predicate.
1446 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1448 ty::Predicate::Trait(ref data) => {
1449 WalkTysIter::InputTypes(data.skip_binder().input_types())
1451 ty::Predicate::Subtype(binder) => {
1452 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1453 WalkTysIter::Two(a, b)
1455 ty::Predicate::TypeOutlives(binder) => {
1456 WalkTysIter::One(binder.skip_binder().0)
1458 ty::Predicate::RegionOutlives(..) => {
1461 ty::Predicate::Projection(ref data) => {
1462 let inner = data.skip_binder();
1463 WalkTysIter::ProjectionTypes(
1464 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1466 ty::Predicate::WellFormed(data) => {
1467 WalkTysIter::One(data)
1469 ty::Predicate::ObjectSafe(_trait_def_id) => {
1472 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1473 WalkTysIter::Types(closure_substs.types())
1475 ty::Predicate::ConstEvaluatable(_, substs) => {
1476 WalkTysIter::Types(substs.types())
1481 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1483 Predicate::Trait(ref t) => {
1484 Some(t.to_poly_trait_ref())
1486 Predicate::Projection(..) |
1487 Predicate::Subtype(..) |
1488 Predicate::RegionOutlives(..) |
1489 Predicate::WellFormed(..) |
1490 Predicate::ObjectSafe(..) |
1491 Predicate::ClosureKind(..) |
1492 Predicate::TypeOutlives(..) |
1493 Predicate::ConstEvaluatable(..) => {
1499 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1501 Predicate::TypeOutlives(data) => {
1504 Predicate::Trait(..) |
1505 Predicate::Projection(..) |
1506 Predicate::Subtype(..) |
1507 Predicate::RegionOutlives(..) |
1508 Predicate::WellFormed(..) |
1509 Predicate::ObjectSafe(..) |
1510 Predicate::ClosureKind(..) |
1511 Predicate::ConstEvaluatable(..) => {
1518 /// Represents the bounds declared on a particular set of type
1519 /// parameters. Should eventually be generalized into a flag list of
1520 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1521 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1522 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1523 /// the `GenericPredicates` are expressed in terms of the bound type
1524 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1525 /// represented a set of bounds for some particular instantiation,
1526 /// meaning that the generic parameters have been substituted with
1531 /// struct Foo<T, U: Bar<T>> { ... }
1533 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1534 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1535 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1536 /// [usize:Bar<isize>]]`.
1537 #[derive(Clone, Debug)]
1538 pub struct InstantiatedPredicates<'tcx> {
1539 pub predicates: Vec<Predicate<'tcx>>,
1542 impl<'tcx> InstantiatedPredicates<'tcx> {
1543 pub fn empty() -> InstantiatedPredicates<'tcx> {
1544 InstantiatedPredicates { predicates: vec![] }
1547 pub fn is_empty(&self) -> bool {
1548 self.predicates.is_empty()
1552 rustc_index::newtype_index! {
1553 /// "Universes" are used during type- and trait-checking in the
1554 /// presence of `for<..>` binders to control what sets of names are
1555 /// visible. Universes are arranged into a tree: the root universe
1556 /// contains names that are always visible. Each child then adds a new
1557 /// set of names that are visible, in addition to those of its parent.
1558 /// We say that the child universe "extends" the parent universe with
1561 /// To make this more concrete, consider this program:
1565 /// fn bar<T>(x: T) {
1566 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1570 /// The struct name `Foo` is in the root universe U0. But the type
1571 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1572 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1573 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1574 /// region `'a` is in a universe U2 that extends U1, because we can
1575 /// name it inside the fn type but not outside.
1577 /// Universes are used to do type- and trait-checking around these
1578 /// "forall" binders (also called **universal quantification**). The
1579 /// idea is that when, in the body of `bar`, we refer to `T` as a
1580 /// type, we aren't referring to any type in particular, but rather a
1581 /// kind of "fresh" type that is distinct from all other types we have
1582 /// actually declared. This is called a **placeholder** type, and we
1583 /// use universes to talk about this. In other words, a type name in
1584 /// universe 0 always corresponds to some "ground" type that the user
1585 /// declared, but a type name in a non-zero universe is a placeholder
1586 /// type -- an idealized representative of "types in general" that we
1587 /// use for checking generic functions.
1588 pub struct UniverseIndex {
1589 DEBUG_FORMAT = "U{}",
1593 impl_stable_hash_for!(struct UniverseIndex { private });
1595 impl UniverseIndex {
1596 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1598 /// Returns the "next" universe index in order -- this new index
1599 /// is considered to extend all previous universes. This
1600 /// corresponds to entering a `forall` quantifier. So, for
1601 /// example, suppose we have this type in universe `U`:
1604 /// for<'a> fn(&'a u32)
1607 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1608 /// new universe that extends `U` -- in this new universe, we can
1609 /// name the region `'a`, but that region was not nameable from
1610 /// `U` because it was not in scope there.
1611 pub fn next_universe(self) -> UniverseIndex {
1612 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1615 /// Returns `true` if `self` can name a name from `other` -- in other words,
1616 /// if the set of names in `self` is a superset of those in
1617 /// `other` (`self >= other`).
1618 pub fn can_name(self, other: UniverseIndex) -> bool {
1619 self.private >= other.private
1622 /// Returns `true` if `self` cannot name some names from `other` -- in other
1623 /// words, if the set of names in `self` is a strict subset of
1624 /// those in `other` (`self < other`).
1625 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1626 self.private < other.private
1630 /// The "placeholder index" fully defines a placeholder region.
1631 /// Placeholder regions are identified by both a **universe** as well
1632 /// as a "bound-region" within that universe. The `bound_region` is
1633 /// basically a name -- distinct bound regions within the same
1634 /// universe are just two regions with an unknown relationship to one
1636 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1637 pub struct Placeholder<T> {
1638 pub universe: UniverseIndex,
1642 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1644 T: HashStable<StableHashingContext<'a>>,
1646 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1647 self.universe.hash_stable(hcx, hasher);
1648 self.name.hash_stable(hcx, hasher);
1652 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1654 pub type PlaceholderType = Placeholder<BoundVar>;
1656 pub type PlaceholderConst = Placeholder<BoundVar>;
1658 /// When type checking, we use the `ParamEnv` to track
1659 /// details about the set of where-clauses that are in scope at this
1660 /// particular point.
1661 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1662 pub struct ParamEnv<'tcx> {
1663 /// `Obligation`s that the caller must satisfy. This is basically
1664 /// the set of bounds on the in-scope type parameters, translated
1665 /// into `Obligation`s, and elaborated and normalized.
1666 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1668 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1669 /// want `Reveal::All` -- note that this is always paired with an
1670 /// empty environment. To get that, use `ParamEnv::reveal()`.
1671 pub reveal: traits::Reveal,
1673 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1674 /// register that `def_id` (useful for transitioning to the chalk trait
1676 pub def_id: Option<DefId>,
1679 impl<'tcx> ParamEnv<'tcx> {
1680 /// Construct a trait environment suitable for contexts where
1681 /// there are no where-clauses in scope. Hidden types (like `impl
1682 /// Trait`) are left hidden, so this is suitable for ordinary
1685 pub fn empty() -> Self {
1686 Self::new(List::empty(), Reveal::UserFacing, None)
1689 /// Construct a trait environment with no where-clauses in scope
1690 /// where the values of all `impl Trait` and other hidden types
1691 /// are revealed. This is suitable for monomorphized, post-typeck
1692 /// environments like codegen or doing optimizations.
1694 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1695 /// or invoke `param_env.with_reveal_all()`.
1697 pub fn reveal_all() -> Self {
1698 Self::new(List::empty(), Reveal::All, None)
1701 /// Construct a trait environment with the given set of predicates.
1704 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1706 def_id: Option<DefId>
1708 ty::ParamEnv { caller_bounds, reveal, def_id }
1711 /// Returns a new parameter environment with the same clauses, but
1712 /// which "reveals" the true results of projections in all cases
1713 /// (even for associated types that are specializable). This is
1714 /// the desired behavior during codegen and certain other special
1715 /// contexts; normally though we want to use `Reveal::UserFacing`,
1716 /// which is the default.
1717 pub fn with_reveal_all(self) -> Self {
1718 ty::ParamEnv { reveal: Reveal::All, ..self }
1721 /// Returns this same environment but with no caller bounds.
1722 pub fn without_caller_bounds(self) -> Self {
1723 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1726 /// Creates a suitable environment in which to perform trait
1727 /// queries on the given value. When type-checking, this is simply
1728 /// the pair of the environment plus value. But when reveal is set to
1729 /// All, then if `value` does not reference any type parameters, we will
1730 /// pair it with the empty environment. This improves caching and is generally
1733 /// N.B., we preserve the environment when type-checking because it
1734 /// is possible for the user to have wacky where-clauses like
1735 /// `where Box<u32>: Copy`, which are clearly never
1736 /// satisfiable. We generally want to behave as if they were true,
1737 /// although the surrounding function is never reachable.
1738 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1740 Reveal::UserFacing => {
1748 if value.has_placeholders()
1749 || value.needs_infer()
1750 || value.has_param_types()
1758 param_env: self.without_caller_bounds(),
1767 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1768 pub struct ParamEnvAnd<'tcx, T> {
1769 pub param_env: ParamEnv<'tcx>,
1773 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1774 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1775 (self.param_env, self.value)
1779 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1781 T: HashStable<StableHashingContext<'a>>,
1783 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1789 param_env.hash_stable(hcx, hasher);
1790 value.hash_stable(hcx, hasher);
1794 #[derive(Copy, Clone, Debug, HashStable)]
1795 pub struct Destructor {
1796 /// The `DefId` of the destructor method
1801 #[derive(HashStable)]
1802 pub struct AdtFlags: u32 {
1803 const NO_ADT_FLAGS = 0;
1804 /// Indicates whether the ADT is an enum.
1805 const IS_ENUM = 1 << 0;
1806 /// Indicates whether the ADT is a union.
1807 const IS_UNION = 1 << 1;
1808 /// Indicates whether the ADT is a struct.
1809 const IS_STRUCT = 1 << 2;
1810 /// Indicates whether the ADT is a struct and has a constructor.
1811 const HAS_CTOR = 1 << 3;
1812 /// Indicates whether the type is a `PhantomData`.
1813 const IS_PHANTOM_DATA = 1 << 4;
1814 /// Indicates whether the type has a `#[fundamental]` attribute.
1815 const IS_FUNDAMENTAL = 1 << 5;
1816 /// Indicates whether the type is a `Box`.
1817 const IS_BOX = 1 << 6;
1818 /// Indicates whether the type is an `Arc`.
1819 const IS_ARC = 1 << 7;
1820 /// Indicates whether the type is an `Rc`.
1821 const IS_RC = 1 << 8;
1822 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1823 /// (i.e., this flag is never set unless this ADT is an enum).
1824 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1829 #[derive(HashStable)]
1830 pub struct VariantFlags: u32 {
1831 const NO_VARIANT_FLAGS = 0;
1832 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1833 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1837 /// Definition of a variant -- a struct's fields or a enum variant.
1839 pub struct VariantDef {
1840 /// `DefId` that identifies the variant itself.
1841 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1843 /// `DefId` that identifies the variant's constructor.
1844 /// If this variant is a struct variant, then this is `None`.
1845 pub ctor_def_id: Option<DefId>,
1846 /// Variant or struct name.
1848 /// Discriminant of this variant.
1849 pub discr: VariantDiscr,
1850 /// Fields of this variant.
1851 pub fields: Vec<FieldDef>,
1852 /// Type of constructor of variant.
1853 pub ctor_kind: CtorKind,
1854 /// Flags of the variant (e.g. is field list non-exhaustive)?
1855 flags: VariantFlags,
1856 /// Variant is obtained as part of recovering from a syntactic error.
1857 /// May be incomplete or bogus.
1858 pub recovered: bool,
1861 impl<'tcx> VariantDef {
1862 /// Creates a new `VariantDef`.
1864 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1865 /// represents an enum variant).
1867 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1868 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1870 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1871 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1872 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1873 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1874 /// built-in trait), and we do not want to load attributes twice.
1876 /// If someone speeds up attribute loading to not be a performance concern, they can
1877 /// remove this hack and use the constructor `DefId` everywhere.
1881 variant_did: Option<DefId>,
1882 ctor_def_id: Option<DefId>,
1883 discr: VariantDiscr,
1884 fields: Vec<FieldDef>,
1885 ctor_kind: CtorKind,
1891 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1892 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1893 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1896 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1897 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1898 debug!("found non-exhaustive field list for {:?}", parent_did);
1899 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1900 } else if let Some(variant_did) = variant_did {
1901 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1902 debug!("found non-exhaustive field list for {:?}", variant_did);
1903 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1908 def_id: variant_did.unwrap_or(parent_did),
1919 /// Is this field list non-exhaustive?
1921 pub fn is_field_list_non_exhaustive(&self) -> bool {
1922 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1926 impl_stable_hash_for!(struct VariantDef {
1929 ident -> (ident.name),
1937 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1938 pub enum VariantDiscr {
1939 /// Explicit value for this variant, i.e., `X = 123`.
1940 /// The `DefId` corresponds to the embedded constant.
1943 /// The previous variant's discriminant plus one.
1944 /// For efficiency reasons, the distance from the
1945 /// last `Explicit` discriminant is being stored,
1946 /// or `0` for the first variant, if it has none.
1950 #[derive(Debug, HashStable)]
1951 pub struct FieldDef {
1953 #[stable_hasher(project(name))]
1955 pub vis: Visibility,
1958 /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
1960 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1962 /// The initialism *"Adt"* stands for an [*algebraic data type (ADT)*][adt].
1963 /// This is slightly wrong because `union`s are not ADTs.
1964 /// Moreover, Rust only allows recursive data types through indirection.
1966 /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
1968 /// `DefId` of the struct, enum or union item.
1970 /// Variants of the ADT. If this is a struct or union, then there will be a single variant.
1971 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1972 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1974 /// Repr options provided by the user.
1975 pub repr: ReprOptions,
1978 impl PartialOrd for AdtDef {
1979 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1980 Some(self.cmp(&other))
1984 /// There should be only one AdtDef for each `did`, therefore
1985 /// it is fine to implement `Ord` only based on `did`.
1986 impl Ord for AdtDef {
1987 fn cmp(&self, other: &AdtDef) -> Ordering {
1988 self.did.cmp(&other.did)
1992 impl PartialEq for AdtDef {
1993 // AdtDef are always interned and this is part of TyS equality
1995 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1998 impl Eq for AdtDef {}
2000 impl Hash for AdtDef {
2002 fn hash<H: Hasher>(&self, s: &mut H) {
2003 (self as *const AdtDef).hash(s)
2007 impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef {
2008 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
2013 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {}
2016 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
2017 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
2019 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
2022 let hash: Fingerprint = CACHE.with(|cache| {
2023 let addr = self as *const AdtDef as usize;
2024 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2032 let mut hasher = StableHasher::new();
2033 did.hash_stable(hcx, &mut hasher);
2034 variants.hash_stable(hcx, &mut hasher);
2035 flags.hash_stable(hcx, &mut hasher);
2036 repr.hash_stable(hcx, &mut hasher);
2042 hash.hash_stable(hcx, hasher);
2046 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2047 pub enum AdtKind { Struct, Union, Enum }
2049 impl Into<DataTypeKind> for AdtKind {
2050 fn into(self) -> DataTypeKind {
2052 AdtKind::Struct => DataTypeKind::Struct,
2053 AdtKind::Union => DataTypeKind::Union,
2054 AdtKind::Enum => DataTypeKind::Enum,
2060 #[derive(RustcEncodable, RustcDecodable, Default)]
2061 pub struct ReprFlags: u8 {
2062 const IS_C = 1 << 0;
2063 const IS_SIMD = 1 << 1;
2064 const IS_TRANSPARENT = 1 << 2;
2065 // Internal only for now. If true, don't reorder fields.
2066 const IS_LINEAR = 1 << 3;
2068 // Any of these flags being set prevent field reordering optimisation.
2069 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2070 ReprFlags::IS_SIMD.bits |
2071 ReprFlags::IS_LINEAR.bits;
2075 impl_stable_hash_for!(struct ReprFlags {
2079 /// Represents the repr options provided by the user,
2080 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2081 pub struct ReprOptions {
2082 pub int: Option<attr::IntType>,
2083 pub align: Option<Align>,
2084 pub pack: Option<Align>,
2085 pub flags: ReprFlags,
2088 impl_stable_hash_for!(struct ReprOptions {
2096 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2097 let mut flags = ReprFlags::empty();
2098 let mut size = None;
2099 let mut max_align: Option<Align> = None;
2100 let mut min_pack: Option<Align> = None;
2101 for attr in tcx.get_attrs(did).iter() {
2102 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2103 flags.insert(match r {
2104 attr::ReprC => ReprFlags::IS_C,
2105 attr::ReprPacked(pack) => {
2106 let pack = Align::from_bytes(pack as u64).unwrap();
2107 min_pack = Some(if let Some(min_pack) = min_pack {
2114 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2115 attr::ReprSimd => ReprFlags::IS_SIMD,
2116 attr::ReprInt(i) => {
2120 attr::ReprAlign(align) => {
2121 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2128 // This is here instead of layout because the choice must make it into metadata.
2129 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2130 flags.insert(ReprFlags::IS_LINEAR);
2132 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2136 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2138 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2140 pub fn packed(&self) -> bool { self.pack.is_some() }
2142 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2144 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2146 pub fn discr_type(&self) -> attr::IntType {
2147 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2150 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2151 /// layout" optimizations, such as representing `Foo<&T>` as a
2153 pub fn inhibit_enum_layout_opt(&self) -> bool {
2154 self.c() || self.int.is_some()
2157 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2158 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2159 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2160 if let Some(pack) = self.pack {
2161 if pack.bytes() == 1 {
2165 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2168 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2169 pub fn inhibit_union_abi_opt(&self) -> bool {
2175 /// Creates a new `AdtDef`.
2180 variants: IndexVec<VariantIdx, VariantDef>,
2183 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2184 let mut flags = AdtFlags::NO_ADT_FLAGS;
2186 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2187 debug!("found non-exhaustive variant list for {:?}", did);
2188 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2191 flags |= match kind {
2192 AdtKind::Enum => AdtFlags::IS_ENUM,
2193 AdtKind::Union => AdtFlags::IS_UNION,
2194 AdtKind::Struct => AdtFlags::IS_STRUCT,
2197 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2198 flags |= AdtFlags::HAS_CTOR;
2201 let attrs = tcx.get_attrs(did);
2202 if attr::contains_name(&attrs, sym::fundamental) {
2203 flags |= AdtFlags::IS_FUNDAMENTAL;
2205 if Some(did) == tcx.lang_items().phantom_data() {
2206 flags |= AdtFlags::IS_PHANTOM_DATA;
2208 if Some(did) == tcx.lang_items().owned_box() {
2209 flags |= AdtFlags::IS_BOX;
2211 if Some(did) == tcx.lang_items().arc() {
2212 flags |= AdtFlags::IS_ARC;
2214 if Some(did) == tcx.lang_items().rc() {
2215 flags |= AdtFlags::IS_RC;
2226 /// Returns `true` if this is a struct.
2228 pub fn is_struct(&self) -> bool {
2229 self.flags.contains(AdtFlags::IS_STRUCT)
2232 /// Returns `true` if this is a union.
2234 pub fn is_union(&self) -> bool {
2235 self.flags.contains(AdtFlags::IS_UNION)
2238 /// Returns `true` if this is a enum.
2240 pub fn is_enum(&self) -> bool {
2241 self.flags.contains(AdtFlags::IS_ENUM)
2244 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2246 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2247 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2250 /// Returns the kind of the ADT.
2252 pub fn adt_kind(&self) -> AdtKind {
2255 } else if self.is_union() {
2262 /// Returns a description of this abstract data type.
2263 pub fn descr(&self) -> &'static str {
2264 match self.adt_kind() {
2265 AdtKind::Struct => "struct",
2266 AdtKind::Union => "union",
2267 AdtKind::Enum => "enum",
2271 /// Returns a description of a variant of this abstract data type.
2273 pub fn variant_descr(&self) -> &'static str {
2274 match self.adt_kind() {
2275 AdtKind::Struct => "struct",
2276 AdtKind::Union => "union",
2277 AdtKind::Enum => "variant",
2281 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2283 pub fn has_ctor(&self) -> bool {
2284 self.flags.contains(AdtFlags::HAS_CTOR)
2287 /// Returns `true` if this type is `#[fundamental]` for the purposes
2288 /// of coherence checking.
2290 pub fn is_fundamental(&self) -> bool {
2291 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2294 /// Returns `true` if this is `PhantomData<T>`.
2296 pub fn is_phantom_data(&self) -> bool {
2297 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2300 /// Returns `true` if this is `Arc<T>`.
2301 pub fn is_arc(&self) -> bool {
2302 self.flags.contains(AdtFlags::IS_ARC)
2305 /// Returns `true` if this is `Rc<T>`.
2306 pub fn is_rc(&self) -> bool {
2307 self.flags.contains(AdtFlags::IS_RC)
2310 /// Returns `true` if this is Box<T>.
2312 pub fn is_box(&self) -> bool {
2313 self.flags.contains(AdtFlags::IS_BOX)
2316 /// Returns `true` if this type has a destructor.
2317 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2318 self.destructor(tcx).is_some()
2321 /// Asserts this is a struct or union and returns its unique variant.
2322 pub fn non_enum_variant(&self) -> &VariantDef {
2323 assert!(self.is_struct() || self.is_union());
2324 &self.variants[VariantIdx::new(0)]
2328 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> {
2329 tcx.predicates_of(self.did)
2332 /// Returns an iterator over all fields contained
2335 pub fn all_fields(&self) -> impl Iterator<Item=&FieldDef> + Clone {
2336 self.variants.iter().flat_map(|v| v.fields.iter())
2339 pub fn is_payloadfree(&self) -> bool {
2340 !self.variants.is_empty() &&
2341 self.variants.iter().all(|v| v.fields.is_empty())
2344 /// Return a `VariantDef` given a variant id.
2345 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2346 self.variants.iter().find(|v| v.def_id == vid)
2347 .expect("variant_with_id: unknown variant")
2350 /// Return a `VariantDef` given a constructor id.
2351 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2352 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2353 .expect("variant_with_ctor_id: unknown variant")
2356 /// Return the index of `VariantDef` given a variant id.
2357 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2358 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2359 .expect("variant_index_with_id: unknown variant").0
2362 /// Return the index of `VariantDef` given a constructor id.
2363 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2364 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2365 .expect("variant_index_with_ctor_id: unknown variant").0
2368 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2370 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2371 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2372 Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
2373 Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) |
2374 Res::SelfCtor(..) => self.non_enum_variant(),
2375 _ => bug!("unexpected res {:?} in variant_of_res", res)
2380 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2381 let param_env = tcx.param_env(expr_did);
2382 let repr_type = self.repr.discr_type();
2383 let substs = InternalSubsts::identity_for_item(tcx, expr_did);
2384 let instance = ty::Instance::new(expr_did, substs);
2385 let cid = GlobalId {
2389 match tcx.const_eval(param_env.and(cid)) {
2391 // FIXME: Find the right type and use it instead of `val.ty` here
2392 if let Some(b) = val.try_eval_bits(tcx, param_env, val.ty) {
2393 trace!("discriminants: {} ({:?})", b, repr_type);
2399 info!("invalid enum discriminant: {:#?}", val);
2400 crate::mir::interpret::struct_error(
2401 tcx.at(tcx.def_span(expr_did)),
2402 "constant evaluation of enum discriminant resulted in non-integer",
2407 Err(ErrorHandled::Reported) => {
2408 if !expr_did.is_local() {
2409 span_bug!(tcx.def_span(expr_did),
2410 "variant discriminant evaluation succeeded \
2411 in its crate but failed locally");
2415 Err(ErrorHandled::TooGeneric) => span_bug!(
2416 tcx.def_span(expr_did),
2417 "enum discriminant depends on generic arguments",
2423 pub fn discriminants(
2426 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2427 let repr_type = self.repr.discr_type();
2428 let initial = repr_type.initial_discriminant(tcx);
2429 let mut prev_discr = None::<Discr<'tcx>>;
2430 self.variants.iter_enumerated().map(move |(i, v)| {
2431 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2432 if let VariantDiscr::Explicit(expr_did) = v.discr {
2433 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2437 prev_discr = Some(discr);
2444 pub fn variant_range(&self) -> Range<VariantIdx> {
2445 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2448 /// Computes the discriminant value used by a specific variant.
2449 /// Unlike `discriminants`, this is (amortized) constant-time,
2450 /// only doing at most one query for evaluating an explicit
2451 /// discriminant (the last one before the requested variant),
2452 /// assuming there are no constant-evaluation errors there.
2454 pub fn discriminant_for_variant(
2457 variant_index: VariantIdx,
2459 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2460 let explicit_value = val
2461 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2462 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
2463 explicit_value.checked_add(tcx, offset as u128).0
2466 /// Yields a `DefId` for the discriminant and an offset to add to it
2467 /// Alternatively, if there is no explicit discriminant, returns the
2468 /// inferred discriminant directly.
2469 pub fn discriminant_def_for_variant(
2471 variant_index: VariantIdx,
2472 ) -> (Option<DefId>, u32) {
2473 let mut explicit_index = variant_index.as_u32();
2476 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2477 ty::VariantDiscr::Relative(0) => {
2481 ty::VariantDiscr::Relative(distance) => {
2482 explicit_index -= distance;
2484 ty::VariantDiscr::Explicit(did) => {
2485 expr_did = Some(did);
2490 (expr_did, variant_index.as_u32() - explicit_index)
2493 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2494 tcx.adt_destructor(self.did)
2497 /// Returns a list of types such that `Self: Sized` if and only
2498 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2500 /// Oddly enough, checking that the sized-constraint is `Sized` is
2501 /// actually more expressive than checking all members:
2502 /// the `Sized` trait is inductive, so an associated type that references
2503 /// `Self` would prevent its containing ADT from being `Sized`.
2505 /// Due to normalization being eager, this applies even if
2506 /// the associated type is behind a pointer (e.g., issue #31299).
2507 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2508 tcx.adt_sized_constraint(self.did).0
2511 fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> {
2512 let result = match ty.kind {
2513 Bool | Char | Int(..) | Uint(..) | Float(..) |
2514 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2515 Array(..) | Closure(..) | Generator(..) | Never => {
2524 GeneratorWitness(..) => {
2525 // these are never sized - return the target type
2532 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2536 Adt(adt, substs) => {
2538 let adt_tys = adt.sized_constraint(tcx);
2539 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2542 .map(|ty| ty.subst(tcx, substs))
2543 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2547 Projection(..) | Opaque(..) => {
2548 // must calculate explicitly.
2549 // FIXME: consider special-casing always-Sized projections
2553 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2556 // perf hack: if there is a `T: Sized` bound, then
2557 // we know that `T` is Sized and do not need to check
2560 let sized_trait = match tcx.lang_items().sized_trait() {
2562 _ => return vec![ty]
2564 let sized_predicate = Binder::dummy(TraitRef {
2565 def_id: sized_trait,
2566 substs: tcx.mk_substs_trait(ty, &[])
2568 let predicates = tcx.predicates_of(self.did).predicates;
2569 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2579 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2583 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2588 impl<'tcx> FieldDef {
2589 /// Returns the type of this field. The `subst` is typically obtained
2590 /// via the second field of `TyKind::AdtDef`.
2591 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2592 tcx.type_of(self.did).subst(tcx, subst)
2596 /// Represents the various closure traits in the language. This
2597 /// will determine the type of the environment (`self`, in the
2598 /// desugaring) argument that the closure expects.
2600 /// You can get the environment type of a closure using
2601 /// `tcx.closure_env_ty()`.
2602 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2603 RustcEncodable, RustcDecodable, HashStable)]
2604 pub enum ClosureKind {
2605 // Warning: Ordering is significant here! The ordering is chosen
2606 // because the trait Fn is a subtrait of FnMut and so in turn, and
2607 // hence we order it so that Fn < FnMut < FnOnce.
2613 impl<'tcx> ClosureKind {
2614 // This is the initial value used when doing upvar inference.
2615 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2617 pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
2619 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem, None),
2620 ClosureKind::FnMut => {
2621 tcx.require_lang_item(FnMutTraitLangItem, None)
2623 ClosureKind::FnOnce => {
2624 tcx.require_lang_item(FnOnceTraitLangItem, None)
2629 /// Returns `true` if this a type that impls this closure kind
2630 /// must also implement `other`.
2631 pub fn extends(self, other: ty::ClosureKind) -> bool {
2632 match (self, other) {
2633 (ClosureKind::Fn, ClosureKind::Fn) => true,
2634 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2635 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2636 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2637 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2638 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2643 /// Returns the representative scalar type for this closure kind.
2644 /// See `TyS::to_opt_closure_kind` for more details.
2645 pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
2647 ty::ClosureKind::Fn => tcx.types.i8,
2648 ty::ClosureKind::FnMut => tcx.types.i16,
2649 ty::ClosureKind::FnOnce => tcx.types.i32,
2654 impl<'tcx> TyS<'tcx> {
2655 /// Iterator that walks `self` and any types reachable from
2656 /// `self`, in depth-first order. Note that just walks the types
2657 /// that appear in `self`, it does not descend into the fields of
2658 /// structs or variants. For example:
2661 /// isize => { isize }
2662 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2663 /// [isize] => { [isize], isize }
2665 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2666 TypeWalker::new(self)
2669 /// Iterator that walks the immediate children of `self`. Hence
2670 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2671 /// (but not `i32`, like `walk`).
2672 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2673 walk::walk_shallow(self)
2676 /// Walks `ty` and any types appearing within `ty`, invoking the
2677 /// callback `f` on each type. If the callback returns `false`, then the
2678 /// children of the current type are ignored.
2680 /// Note: prefer `ty.walk()` where possible.
2681 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2682 where F: FnMut(Ty<'tcx>) -> bool
2684 let mut walker = self.walk();
2685 while let Some(ty) = walker.next() {
2687 walker.skip_current_subtree();
2694 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2696 hir::Mutability::Mutable => MutBorrow,
2697 hir::Mutability::Immutable => ImmBorrow,
2701 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2702 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2703 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2705 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2707 MutBorrow => hir::Mutability::Mutable,
2708 ImmBorrow => hir::Mutability::Immutable,
2710 // We have no type corresponding to a unique imm borrow, so
2711 // use `&mut`. It gives all the capabilities of an `&uniq`
2712 // and hence is a safe "over approximation".
2713 UniqueImmBorrow => hir::Mutability::Mutable,
2717 pub fn to_user_str(&self) -> &'static str {
2719 MutBorrow => "mutable",
2720 ImmBorrow => "immutable",
2721 UniqueImmBorrow => "uniquely immutable",
2726 #[derive(Debug, Clone)]
2727 pub enum Attributes<'tcx> {
2728 Owned(Lrc<[ast::Attribute]>),
2729 Borrowed(&'tcx [ast::Attribute]),
2732 impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
2733 type Target = [ast::Attribute];
2735 fn deref(&self) -> &[ast::Attribute] {
2737 &Attributes::Owned(ref data) => &data,
2738 &Attributes::Borrowed(data) => data
2743 #[derive(Debug, PartialEq, Eq)]
2744 pub enum ImplOverlapKind {
2745 /// These impls are always allowed to overlap.
2747 /// These impls are allowed to overlap, but that raises
2748 /// an issue #33140 future-compatibility warning.
2750 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2751 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2753 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2754 /// that difference, making what reduces to the following set of impls:
2758 /// impl Trait for dyn Send + Sync {}
2759 /// impl Trait for dyn Sync + Send {}
2762 /// Obviously, once we made these types be identical, that code causes a coherence
2763 /// error and a fairly big headache for us. However, luckily for us, the trait
2764 /// `Trait` used in this case is basically a marker trait, and therefore having
2765 /// overlapping impls for it is sound.
2767 /// To handle this, we basically regard the trait as a marker trait, with an additional
2768 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2769 /// it has the following restrictions:
2771 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2773 /// 2. The trait-ref of both impls must be equal.
2774 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2776 /// 4. Neither of the impls can have any where-clauses.
2778 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2782 impl<'tcx> TyCtxt<'tcx> {
2783 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
2784 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2787 /// Returns an iterator of the `DefId`s for all body-owners in this
2788 /// crate. If you would prefer to iterate over the bodies
2789 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2790 pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
2794 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2797 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2798 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2799 f(self.hir().body_owner_def_id(body_id))
2803 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
2804 self.associated_items(id)
2805 .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
2809 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2810 self.associated_items(did).any(|item| {
2811 item.relevant_for_never()
2815 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
2816 self.hir().as_local_hir_id(def_id).and_then(|hir_id| self.hir().get(hir_id).ident())
2819 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
2820 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2821 match self.hir().get(hir_id) {
2822 Node::TraitItem(_) | Node::ImplItem(_) => true,
2826 match self.def_kind(def_id).expect("no def for `DefId`") {
2829 | DefKind::AssocTy => true,
2834 if is_associated_item {
2835 Some(self.associated_item(def_id))
2841 fn associated_item_from_trait_item_ref(self,
2842 parent_def_id: DefId,
2843 parent_vis: &hir::Visibility,
2844 trait_item_ref: &hir::TraitItemRef)
2846 let def_id = self.hir().local_def_id(trait_item_ref.id.hir_id);
2847 let (kind, has_self) = match trait_item_ref.kind {
2848 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2849 hir::AssocItemKind::Method { has_self } => {
2850 (ty::AssocKind::Method, has_self)
2852 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2853 hir::AssocItemKind::OpaqueTy => bug!("only impls can have opaque types"),
2857 ident: trait_item_ref.ident,
2859 // Visibility of trait items is inherited from their traits.
2860 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2861 defaultness: trait_item_ref.defaultness,
2863 container: TraitContainer(parent_def_id),
2864 method_has_self_argument: has_self
2868 fn associated_item_from_impl_item_ref(self,
2869 parent_def_id: DefId,
2870 impl_item_ref: &hir::ImplItemRef)
2872 let def_id = self.hir().local_def_id(impl_item_ref.id.hir_id);
2873 let (kind, has_self) = match impl_item_ref.kind {
2874 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2875 hir::AssocItemKind::Method { has_self } => {
2876 (ty::AssocKind::Method, has_self)
2878 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2879 hir::AssocItemKind::OpaqueTy => (ty::AssocKind::OpaqueTy, false),
2883 ident: impl_item_ref.ident,
2885 // Visibility of trait impl items doesn't matter.
2886 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2887 defaultness: impl_item_ref.defaultness,
2889 container: ImplContainer(parent_def_id),
2890 method_has_self_argument: has_self
2894 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2895 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2898 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2899 variant.fields.iter().position(|field| {
2900 self.hygienic_eq(ident, field.ident, variant.def_id)
2904 pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
2905 // Ideally, we would use `-> impl Iterator` here, but it falls
2906 // afoul of the conservative "capture [restrictions]" we put
2907 // in place, so we use a hand-written iterator.
2909 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2910 AssocItemsIterator {
2912 def_ids: self.associated_item_def_ids(def_id),
2917 /// Returns `true` if the impls are the same polarity and the trait either
2918 /// has no items or is annotated #[marker] and prevents item overrides.
2919 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2920 -> Option<ImplOverlapKind>
2922 // If either trait impl references an error, they're allowed to overlap,
2923 // as one of them essentially doesn't exist.
2924 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error()) ||
2925 self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error()) {
2926 return Some(ImplOverlapKind::Permitted);
2929 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2930 (ImplPolarity::Reservation, _) |
2931 (_, ImplPolarity::Reservation) => {
2932 // `#[rustc_reservation_impl]` impls don't overlap with anything
2933 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2935 return Some(ImplOverlapKind::Permitted);
2937 (ImplPolarity::Positive, ImplPolarity::Negative) |
2938 (ImplPolarity::Negative, ImplPolarity::Positive) => {
2939 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2940 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2944 (ImplPolarity::Positive, ImplPolarity::Positive) |
2945 (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2948 let is_marker_overlap = if self.features().overlapping_marker_traits {
2949 let trait1_is_empty = self.impl_trait_ref(def_id1)
2950 .map_or(false, |trait_ref| {
2951 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2953 let trait2_is_empty = self.impl_trait_ref(def_id2)
2954 .map_or(false, |trait_ref| {
2955 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2957 trait1_is_empty && trait2_is_empty
2959 let is_marker_impl = |def_id: DefId| -> bool {
2960 let trait_ref = self.impl_trait_ref(def_id);
2961 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2963 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2967 if is_marker_overlap {
2968 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2970 Some(ImplOverlapKind::Permitted)
2972 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2973 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2974 if self_ty1 == self_ty2 {
2975 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2977 return Some(ImplOverlapKind::Issue33140);
2979 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2980 def_id1, def_id2, self_ty1, self_ty2);
2985 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2991 /// Returns `ty::VariantDef` if `res` refers to a struct,
2992 /// or variant or their constructors, panics otherwise.
2993 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2995 Res::Def(DefKind::Variant, did) => {
2996 let enum_did = self.parent(did).unwrap();
2997 self.adt_def(enum_did).variant_with_id(did)
2999 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
3000 self.adt_def(did).non_enum_variant()
3002 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
3003 let variant_did = self.parent(variant_ctor_did).unwrap();
3004 let enum_did = self.parent(variant_did).unwrap();
3005 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
3007 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
3008 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
3009 self.adt_def(struct_did).non_enum_variant()
3011 _ => bug!("expect_variant_res used with unexpected res {:?}", res)
3015 pub fn item_name(self, id: DefId) -> Symbol {
3016 if id.index == CRATE_DEF_INDEX {
3017 self.original_crate_name(id.krate)
3019 let def_key = self.def_key(id);
3020 match def_key.disambiguated_data.data {
3021 // The name of a constructor is that of its parent.
3022 hir_map::DefPathData::Ctor =>
3023 self.item_name(DefId {
3025 index: def_key.parent.unwrap()
3027 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
3028 bug!("item_name: no name for {:?}", self.def_path(id));
3034 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
3035 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
3037 ty::InstanceDef::Item(did) => {
3038 self.optimized_mir(did)
3040 ty::InstanceDef::VtableShim(..) |
3041 ty::InstanceDef::ReifyShim(..) |
3042 ty::InstanceDef::Intrinsic(..) |
3043 ty::InstanceDef::FnPtrShim(..) |
3044 ty::InstanceDef::Virtual(..) |
3045 ty::InstanceDef::ClosureOnceShim { .. } |
3046 ty::InstanceDef::DropGlue(..) |
3047 ty::InstanceDef::CloneShim(..) => {
3048 self.mir_shims(instance)
3053 /// Gets the attributes of a definition.
3054 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
3055 if let Some(id) = self.hir().as_local_hir_id(did) {
3056 Attributes::Borrowed(self.hir().attrs(id))
3058 Attributes::Owned(self.item_attrs(did))
3062 /// Determines whether an item is annotated with an attribute.
3063 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
3064 attr::contains_name(&self.get_attrs(did), attr)
3067 /// Returns `true` if this is an `auto trait`.
3068 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3069 self.trait_def(trait_def_id).has_auto_impl
3072 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3073 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3076 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3077 /// If it implements no trait, returns `None`.
3078 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3079 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3082 /// If the given defid describes a method belonging to an impl, returns the
3083 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3084 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3085 let item = if def_id.krate != LOCAL_CRATE {
3086 if let Some(DefKind::Method) = self.def_kind(def_id) {
3087 Some(self.associated_item(def_id))
3092 self.opt_associated_item(def_id)
3095 item.and_then(|trait_item|
3096 match trait_item.container {
3097 TraitContainer(_) => None,
3098 ImplContainer(def_id) => Some(def_id),
3103 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3104 /// with the name of the crate containing the impl.
3105 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3106 if impl_did.is_local() {
3107 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3108 Ok(self.hir().span(hir_id))
3110 Err(self.crate_name(impl_did.krate))
3114 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3115 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3116 /// definition's parent/scope to perform comparison.
3117 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3118 // We could use `Ident::eq` here, but we deliberately don't. The name
3119 // comparison fails frequently, and we want to avoid the expensive
3120 // `modern()` calls required for the span comparison whenever possible.
3121 use_name.name == def_name.name &&
3122 use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
3123 self.expansion_that_defined(def_parent_def_id))
3126 fn expansion_that_defined(self, scope: DefId) -> ExpnId {
3128 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3129 _ => ExpnId::root(),
3133 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
3134 ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
3138 pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
3140 let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
3141 Some(actual_expansion) =>
3142 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3143 None => self.hir().get_module_parent(block),
3150 pub struct AssocItemsIterator<'tcx> {
3152 def_ids: &'tcx [DefId],
3156 impl Iterator for AssocItemsIterator<'_> {
3157 type Item = AssocItem;
3159 fn next(&mut self) -> Option<AssocItem> {
3160 let def_id = self.def_ids.get(self.next_index)?;
3161 self.next_index += 1;
3162 Some(self.tcx.associated_item(*def_id))
3166 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
3167 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3168 let parent_id = tcx.hir().get_parent_item(id);
3169 let parent_def_id = tcx.hir().local_def_id(parent_id);
3170 let parent_item = tcx.hir().expect_item(parent_id);
3171 match parent_item.kind {
3172 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3173 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3174 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3176 debug_assert_eq!(assoc_item.def_id, def_id);
3181 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3182 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3183 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3186 debug_assert_eq!(assoc_item.def_id, def_id);
3194 span_bug!(parent_item.span,
3195 "unexpected parent of trait or impl item or item not found: {:?}",
3199 #[derive(Clone, HashStable)]
3200 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3202 /// Calculates the `Sized` constraint.
3204 /// In fact, there are only a few options for the types in the constraint:
3205 /// - an obviously-unsized type
3206 /// - a type parameter or projection whose Sizedness can't be known
3207 /// - a tuple of type parameters or projections, if there are multiple
3209 /// - a Error, if a type contained itself. The representability
3210 /// check should catch this case.
3211 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
3212 let def = tcx.adt_def(def_id);
3214 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3217 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3220 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3222 AdtSizedConstraint(result)
3225 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
3226 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3227 let item = tcx.hir().expect_item(id);
3229 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3230 tcx.arena.alloc_from_iter(
3231 trait_item_refs.iter()
3232 .map(|trait_item_ref| trait_item_ref.id)
3233 .map(|id| tcx.hir().local_def_id(id.hir_id))
3236 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3237 tcx.arena.alloc_from_iter(
3238 impl_item_refs.iter()
3239 .map(|impl_item_ref| impl_item_ref.id)
3240 .map(|id| tcx.hir().local_def_id(id.hir_id))
3243 hir::ItemKind::TraitAlias(..) => &[],
3244 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3248 fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
3249 tcx.hir().span_if_local(def_id).unwrap()
3252 /// If the given `DefId` describes an item belonging to a trait,
3253 /// returns the `DefId` of the trait that the trait item belongs to;
3254 /// otherwise, returns `None`.
3255 fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3256 tcx.opt_associated_item(def_id)
3257 .and_then(|associated_item| {
3258 match associated_item.container {
3259 TraitContainer(def_id) => Some(def_id),
3260 ImplContainer(_) => None
3265 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3266 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3267 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3268 if let Node::Item(item) = tcx.hir().get(hir_id) {
3269 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
3270 return opaque_ty.impl_trait_fn;
3277 /// See `ParamEnv` struct definition for details.
3278 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
3279 // The param_env of an impl Trait type is its defining function's param_env
3280 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3281 return param_env(tcx, parent);
3283 // Compute the bounds on Self and the type parameters.
3285 let InstantiatedPredicates { predicates } =
3286 tcx.predicates_of(def_id).instantiate_identity(tcx);
3288 // Finally, we have to normalize the bounds in the environment, in
3289 // case they contain any associated type projections. This process
3290 // can yield errors if the put in illegal associated types, like
3291 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3292 // report these errors right here; this doesn't actually feel
3293 // right to me, because constructing the environment feels like a
3294 // kind of a "idempotent" action, but I'm not sure where would be
3295 // a better place. In practice, we construct environments for
3296 // every fn once during type checking, and we'll abort if there
3297 // are any errors at that point, so after type checking you can be
3298 // sure that this will succeed without errors anyway.
3300 let unnormalized_env = ty::ParamEnv::new(
3301 tcx.intern_predicates(&predicates),
3302 traits::Reveal::UserFacing,
3303 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3306 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3307 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
3309 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3310 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3313 fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
3314 assert_eq!(crate_num, LOCAL_CRATE);
3315 tcx.sess.local_crate_disambiguator()
3318 fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
3319 assert_eq!(crate_num, LOCAL_CRATE);
3320 tcx.crate_name.clone()
3323 fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
3324 assert_eq!(crate_num, LOCAL_CRATE);
3325 tcx.hir().crate_hash
3328 fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
3329 match instance_def {
3330 InstanceDef::Item(..) |
3331 InstanceDef::DropGlue(..) => {
3332 let mir = tcx.instance_mir(instance_def);
3333 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3335 // Estimate the size of other compiler-generated shims to be 1.
3340 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3342 /// See [`ImplOverlapKind::Issue33140`] for more details.
3343 fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
3344 debug!("issue33140_self_ty({:?})", def_id);
3346 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3347 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3350 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3352 let is_marker_like =
3353 tcx.impl_polarity(def_id) == ty::ImplPolarity::Positive &&
3354 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3356 // Check whether these impls would be ok for a marker trait.
3357 if !is_marker_like {
3358 debug!("issue33140_self_ty - not marker-like!");
3362 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3363 if trait_ref.substs.len() != 1 {
3364 debug!("issue33140_self_ty - impl has substs!");
3368 let predicates = tcx.predicates_of(def_id);
3369 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3370 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3374 let self_ty = trait_ref.self_ty();
3375 let self_ty_matches = match self_ty.kind {
3376 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3380 if self_ty_matches {
3381 debug!("issue33140_self_ty - MATCHES!");
3384 debug!("issue33140_self_ty - non-matching self type");
3389 /// Check if a function is async.
3390 fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
3391 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap_or_else(|| {
3392 bug!("asyncness: expected local `DefId`, got `{:?}`", def_id)
3395 let node = tcx.hir().get(hir_id);
3397 let fn_like = hir::map::blocks::FnLikeNode::from_node(node).unwrap_or_else(|| {
3398 bug!("asyncness: expected fn-like node but got `{:?}`", def_id);
3404 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3405 context::provide(providers);
3406 erase_regions::provide(providers);
3407 layout::provide(providers);
3408 util::provide(providers);
3409 constness::provide(providers);
3410 *providers = ty::query::Providers {
3413 associated_item_def_ids,
3414 adt_sized_constraint,
3418 crate_disambiguator,
3419 original_crate_name,
3421 trait_impls_of: trait_def::trait_impls_of_provider,
3422 instance_def_size_estimate,
3428 /// A map for the local crate mapping each type to a vector of its
3429 /// inherent impls. This is not meant to be used outside of coherence;
3430 /// rather, you should request the vector for a specific type via
3431 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3432 /// (constructing this map requires touching the entire crate).
3433 #[derive(Clone, Debug, Default, HashStable)]
3434 pub struct CrateInherentImpls {
3435 pub inherent_impls: DefIdMap<Vec<DefId>>,
3438 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable)]
3439 pub struct SymbolName {
3440 // FIXME: we don't rely on interning or equality here - better have
3441 // this be a `&'tcx str`.
3445 impl_stable_hash_for!(struct self::SymbolName {
3450 pub fn new(name: &str) -> SymbolName {
3452 name: Symbol::intern(name)
3457 impl PartialOrd for SymbolName {
3458 fn partial_cmp(&self, other: &SymbolName) -> Option<Ordering> {
3459 self.name.as_str().partial_cmp(&other.name.as_str())
3463 /// Ordering must use the chars to ensure reproducible builds.
3464 impl Ord for SymbolName {
3465 fn cmp(&self, other: &SymbolName) -> Ordering {
3466 self.name.as_str().cmp(&other.name.as_str())
3470 impl fmt::Display for SymbolName {
3471 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3472 fmt::Display::fmt(&self.name, fmt)
3476 impl fmt::Debug for SymbolName {
3477 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3478 fmt::Display::fmt(&self.name, fmt)