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_expand::hygiene::ExpnId;
50 use syntax::symbol::{kw, sym, Symbol};
54 use rustc_data_structures::fx::{FxHashSet, 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::trait_def::TraitDef;
89 pub use self::query::queries;
102 pub mod inhabitedness;
118 mod structural_impls;
123 pub struct ResolverOutputs {
124 pub definitions: hir_map::Definitions,
125 pub cstore: Box<CrateStoreDyn>,
126 pub extern_crate_map: NodeMap<CrateNum>,
127 pub trait_map: TraitMap,
128 pub maybe_unused_trait_imports: NodeSet,
129 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
130 pub export_map: ExportMap<NodeId>,
131 pub glob_map: GlobMap,
132 /// Extern prelude entries. The value is `true` if the entry was introduced
133 /// via `extern crate` item and not `--extern` option or compiler built-in.
134 pub extern_prelude: FxHashMap<Name, bool>,
137 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
138 pub enum AssocItemContainer {
139 TraitContainer(DefId),
140 ImplContainer(DefId),
143 impl AssocItemContainer {
144 /// Asserts that this is the `DefId` of an associated item declared
145 /// in a trait, and returns the trait `DefId`.
146 pub fn assert_trait(&self) -> DefId {
148 TraitContainer(id) => id,
149 _ => bug!("associated item has wrong container type: {:?}", self)
153 pub fn id(&self) -> DefId {
155 TraitContainer(id) => id,
156 ImplContainer(id) => id,
161 /// The "header" of an impl is everything outside the body: a Self type, a trait
162 /// ref (in the case of a trait impl), and a set of predicates (from the
163 /// bounds / where-clauses).
164 #[derive(Clone, Debug)]
165 pub struct ImplHeader<'tcx> {
166 pub impl_def_id: DefId,
167 pub self_ty: Ty<'tcx>,
168 pub trait_ref: Option<TraitRef<'tcx>>,
169 pub predicates: Vec<Predicate<'tcx>>,
172 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
173 pub enum ImplPolarity {
174 /// `impl Trait for Type`
176 /// `impl !Trait for Type`
178 /// `#[rustc_reservation_impl] impl Trait for Type`
180 /// This is a "stability hack", not a real Rust feature.
181 /// See #64631 for details.
185 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
186 pub struct AssocItem {
188 #[stable_hasher(project(name))]
192 pub defaultness: hir::Defaultness,
193 pub container: AssocItemContainer,
195 /// Whether this is a method with an explicit self
196 /// as its first argument, allowing method calls.
197 pub method_has_self_argument: bool,
200 #[derive(Copy, Clone, PartialEq, Debug, HashStable)]
209 pub fn def_kind(&self) -> DefKind {
211 AssocKind::Const => DefKind::AssocConst,
212 AssocKind::Method => DefKind::Method,
213 AssocKind::Type => DefKind::AssocTy,
214 AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
218 /// Tests whether the associated item admits a non-trivial implementation
220 pub fn relevant_for_never(&self) -> bool {
222 AssocKind::OpaqueTy |
224 AssocKind::Type => true,
225 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
226 AssocKind::Method => !self.method_has_self_argument,
230 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
232 ty::AssocKind::Method => {
233 // We skip the binder here because the binder would deanonymize all
234 // late-bound regions, and we don't want method signatures to show up
235 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
236 // regions just fine, showing `fn(&MyType)`.
237 tcx.fn_sig(self.def_id).skip_binder().to_string()
239 ty::AssocKind::Type => format!("type {};", self.ident),
240 // FIXME(type_alias_impl_trait): we should print bounds here too.
241 ty::AssocKind::OpaqueTy => format!("type {};", self.ident),
242 ty::AssocKind::Const => {
243 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
249 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
250 pub enum Visibility {
251 /// Visible everywhere (including in other crates).
253 /// Visible only in the given crate-local module.
255 /// Not visible anywhere in the local crate. This is the visibility of private external items.
259 pub trait DefIdTree: Copy {
260 fn parent(self, id: DefId) -> Option<DefId>;
262 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
263 if descendant.krate != ancestor.krate {
267 while descendant != ancestor {
268 match self.parent(descendant) {
269 Some(parent) => descendant = parent,
270 None => return false,
277 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
278 fn parent(self, id: DefId) -> Option<DefId> {
279 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
284 pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
285 match visibility.node {
286 hir::VisibilityKind::Public => Visibility::Public,
287 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
288 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
289 // If there is no resolution, `resolve` will have already reported an error, so
290 // assume that the visibility is public to avoid reporting more privacy errors.
291 Res::Err => Visibility::Public,
292 def => Visibility::Restricted(def.def_id()),
294 hir::VisibilityKind::Inherited => {
295 Visibility::Restricted(tcx.hir().get_module_parent(id))
300 /// Returns `true` if an item with this visibility is accessible from the given block.
301 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
302 let restriction = match self {
303 // Public items are visible everywhere.
304 Visibility::Public => return true,
305 // Private items from other crates are visible nowhere.
306 Visibility::Invisible => return false,
307 // Restricted items are visible in an arbitrary local module.
308 Visibility::Restricted(other) if other.krate != module.krate => return false,
309 Visibility::Restricted(module) => module,
312 tree.is_descendant_of(module, restriction)
315 /// Returns `true` if this visibility is at least as accessible as the given visibility
316 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
317 let vis_restriction = match vis {
318 Visibility::Public => return self == Visibility::Public,
319 Visibility::Invisible => return true,
320 Visibility::Restricted(module) => module,
323 self.is_accessible_from(vis_restriction, tree)
326 // Returns `true` if this item is visible anywhere in the local crate.
327 pub fn is_visible_locally(self) -> bool {
329 Visibility::Public => true,
330 Visibility::Restricted(def_id) => def_id.is_local(),
331 Visibility::Invisible => false,
336 #[derive(Copy, Clone, PartialEq, RustcDecodable, RustcEncodable, HashStable)]
338 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
339 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
340 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
341 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
344 /// The crate variances map is computed during typeck and contains the
345 /// variance of every item in the local crate. You should not use it
346 /// directly, because to do so will make your pass dependent on the
347 /// HIR of every item in the local crate. Instead, use
348 /// `tcx.variances_of()` to get the variance for a *particular*
350 #[derive(HashStable)]
351 pub struct CrateVariancesMap<'tcx> {
352 /// For each item with generics, maps to a vector of the variance
353 /// of its generics. If an item has no generics, it will have no
355 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
359 /// `a.xform(b)` combines the variance of a context with the
360 /// variance of a type with the following meaning. If we are in a
361 /// context with variance `a`, and we encounter a type argument in
362 /// a position with variance `b`, then `a.xform(b)` is the new
363 /// variance with which the argument appears.
369 /// Here, the "ambient" variance starts as covariant. `*mut T` is
370 /// invariant with respect to `T`, so the variance in which the
371 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
372 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
373 /// respect to its type argument `T`, and hence the variance of
374 /// the `i32` here is `Invariant.xform(Covariant)`, which results
375 /// (again) in `Invariant`.
379 /// fn(*const Vec<i32>, *mut Vec<i32)
381 /// The ambient variance is covariant. A `fn` type is
382 /// contravariant with respect to its parameters, so the variance
383 /// within which both pointer types appear is
384 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
385 /// T` is covariant with respect to `T`, so the variance within
386 /// which the first `Vec<i32>` appears is
387 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
388 /// is true for its `i32` argument. In the `*mut T` case, the
389 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
390 /// and hence the outermost type is `Invariant` with respect to
391 /// `Vec<i32>` (and its `i32` argument).
393 /// Source: Figure 1 of "Taming the Wildcards:
394 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
395 pub fn xform(self, v: ty::Variance) -> ty::Variance {
397 // Figure 1, column 1.
398 (ty::Covariant, ty::Covariant) => ty::Covariant,
399 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
400 (ty::Covariant, ty::Invariant) => ty::Invariant,
401 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
403 // Figure 1, column 2.
404 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
405 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
406 (ty::Contravariant, ty::Invariant) => ty::Invariant,
407 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
409 // Figure 1, column 3.
410 (ty::Invariant, _) => ty::Invariant,
412 // Figure 1, column 4.
413 (ty::Bivariant, _) => ty::Bivariant,
418 // Contains information needed to resolve types and (in the future) look up
419 // the types of AST nodes.
420 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
421 pub struct CReaderCacheKey {
426 // Flags that we track on types. These flags are propagated upwards
427 // through the type during type construction, so that we can quickly
428 // check whether the type has various kinds of types in it without
429 // recursing over the type itself.
431 pub struct TypeFlags: u32 {
432 const HAS_PARAMS = 1 << 0;
433 const HAS_TY_INFER = 1 << 1;
434 const HAS_RE_INFER = 1 << 2;
435 const HAS_RE_PLACEHOLDER = 1 << 3;
437 /// Does this have any `ReEarlyBound` regions? Used to
438 /// determine whether substitition is required, since those
439 /// represent regions that are bound in a `ty::Generics` and
440 /// hence may be substituted.
441 const HAS_RE_EARLY_BOUND = 1 << 4;
443 /// Does this have any region that "appears free" in the type?
444 /// Basically anything but `ReLateBound` and `ReErased`.
445 const HAS_FREE_REGIONS = 1 << 5;
447 /// Is an error type reachable?
448 const HAS_TY_ERR = 1 << 6;
449 const HAS_PROJECTION = 1 << 7;
451 // FIXME: Rename this to the actual property since it's used for generators too
452 const HAS_TY_CLOSURE = 1 << 8;
454 /// `true` if there are "names" of types and regions and so forth
455 /// that are local to a particular fn
456 const HAS_FREE_LOCAL_NAMES = 1 << 9;
458 /// Present if the type belongs in a local type context.
459 /// Only set for Infer other than Fresh.
460 const KEEP_IN_LOCAL_TCX = 1 << 10;
462 /// Does this have any `ReLateBound` regions? Used to check
463 /// if a global bound is safe to evaluate.
464 const HAS_RE_LATE_BOUND = 1 << 11;
466 const HAS_TY_PLACEHOLDER = 1 << 12;
468 const HAS_CT_INFER = 1 << 13;
469 const HAS_CT_PLACEHOLDER = 1 << 14;
471 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
472 TypeFlags::HAS_RE_EARLY_BOUND.bits;
474 /// Flags representing the nominal content of a type,
475 /// computed by FlagsComputation. If you add a new nominal
476 /// flag, it should be added here too.
477 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
478 TypeFlags::HAS_TY_INFER.bits |
479 TypeFlags::HAS_RE_INFER.bits |
480 TypeFlags::HAS_RE_PLACEHOLDER.bits |
481 TypeFlags::HAS_RE_EARLY_BOUND.bits |
482 TypeFlags::HAS_FREE_REGIONS.bits |
483 TypeFlags::HAS_TY_ERR.bits |
484 TypeFlags::HAS_PROJECTION.bits |
485 TypeFlags::HAS_TY_CLOSURE.bits |
486 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
487 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
488 TypeFlags::HAS_RE_LATE_BOUND.bits |
489 TypeFlags::HAS_TY_PLACEHOLDER.bits |
490 TypeFlags::HAS_CT_INFER.bits |
491 TypeFlags::HAS_CT_PLACEHOLDER.bits;
495 #[allow(rustc::usage_of_ty_tykind)]
496 pub struct TyS<'tcx> {
497 pub kind: TyKind<'tcx>,
498 pub flags: TypeFlags,
500 /// This is a kind of confusing thing: it stores the smallest
503 /// (a) the binder itself captures nothing but
504 /// (b) all the late-bound things within the type are captured
505 /// by some sub-binder.
507 /// So, for a type without any late-bound things, like `u32`, this
508 /// will be *innermost*, because that is the innermost binder that
509 /// captures nothing. But for a type `&'D u32`, where `'D` is a
510 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
511 /// -- the binder itself does not capture `D`, but `D` is captured
512 /// by an inner binder.
514 /// We call this concept an "exclusive" binder `D` because all
515 /// De Bruijn indices within the type are contained within `0..D`
517 outer_exclusive_binder: ty::DebruijnIndex,
520 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
521 #[cfg(target_arch = "x86_64")]
522 static_assert_size!(TyS<'_>, 32);
524 impl<'tcx> Ord for TyS<'tcx> {
525 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
526 self.kind.cmp(&other.kind)
530 impl<'tcx> PartialOrd for TyS<'tcx> {
531 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
532 Some(self.kind.cmp(&other.kind))
536 impl<'tcx> PartialEq for TyS<'tcx> {
538 fn eq(&self, other: &TyS<'tcx>) -> bool {
542 impl<'tcx> Eq for TyS<'tcx> {}
544 impl<'tcx> Hash for TyS<'tcx> {
545 fn hash<H: Hasher>(&self, s: &mut H) {
546 (self as *const TyS<'_>).hash(s)
550 impl<'tcx> TyS<'tcx> {
551 pub fn is_primitive_ty(&self) -> bool {
558 Infer(InferTy::IntVar(_)) |
559 Infer(InferTy::FloatVar(_)) |
560 Infer(InferTy::FreshIntTy(_)) |
561 Infer(InferTy::FreshFloatTy(_)) => true,
562 Ref(_, x, _) => x.is_primitive_ty(),
567 pub fn is_suggestable(&self) -> bool {
575 Projection(..) => false,
581 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
582 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
586 // The other fields just provide fast access to information that is
587 // also contained in `kind`, so no need to hash them.
590 outer_exclusive_binder: _,
593 kind.hash_stable(hcx, hasher);
597 #[rustc_diagnostic_item = "Ty"]
598 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
600 impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {}
601 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {}
603 pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
606 /// A dummy type used to force `List` to be unsized while not requiring references to it be wide
608 type OpaqueListContents;
611 /// A wrapper for slices with the additional invariant
612 /// that the slice is interned and no other slice with
613 /// the same contents can exist in the same context.
614 /// This means we can use pointer for both
615 /// equality comparisons and hashing.
616 /// Note: `Slice` was already taken by the `Ty`.
621 opaque: OpaqueListContents,
624 unsafe impl<T: Sync> Sync for List<T> {}
626 impl<T: Copy> List<T> {
628 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
629 assert!(!mem::needs_drop::<T>());
630 assert!(mem::size_of::<T>() != 0);
631 assert!(slice.len() != 0);
633 // Align up the size of the len (usize) field
634 let align = mem::align_of::<T>();
635 let align_mask = align - 1;
636 let offset = mem::size_of::<usize>();
637 let offset = (offset + align_mask) & !align_mask;
639 let size = offset + slice.len() * mem::size_of::<T>();
641 let mem = arena.alloc_raw(
643 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
645 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
647 result.len = slice.len();
649 // Write the elements
650 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
651 arena_slice.copy_from_slice(slice);
658 impl<T: fmt::Debug> fmt::Debug for List<T> {
659 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
664 impl<T: Encodable> Encodable for List<T> {
666 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
671 impl<T> Ord for List<T> where T: Ord {
672 fn cmp(&self, other: &List<T>) -> Ordering {
673 if self == other { Ordering::Equal } else {
674 <[T] as Ord>::cmp(&**self, &**other)
679 impl<T> PartialOrd for List<T> where T: PartialOrd {
680 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
681 if self == other { Some(Ordering::Equal) } else {
682 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
687 impl<T: PartialEq> PartialEq for List<T> {
689 fn eq(&self, other: &List<T>) -> bool {
693 impl<T: Eq> Eq for List<T> {}
695 impl<T> Hash for List<T> {
697 fn hash<H: Hasher>(&self, s: &mut H) {
698 (self as *const List<T>).hash(s)
702 impl<T> Deref for List<T> {
705 fn deref(&self) -> &[T] {
710 impl<T> AsRef<[T]> for List<T> {
712 fn as_ref(&self) -> &[T] {
714 slice::from_raw_parts(self.data.as_ptr(), self.len)
719 impl<'a, T> IntoIterator for &'a List<T> {
721 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
723 fn into_iter(self) -> Self::IntoIter {
728 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
732 pub fn empty<'a>() -> &'a List<T> {
733 #[repr(align(64), C)]
734 struct EmptySlice([u8; 64]);
735 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
736 assert!(mem::align_of::<T>() <= 64);
738 &*(&EMPTY_SLICE as *const _ as *const List<T>)
743 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
744 pub struct UpvarPath {
745 pub hir_id: hir::HirId,
748 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
749 /// the original var ID (that is, the root variable that is referenced
750 /// by the upvar) and the ID of the closure expression.
751 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
753 pub var_path: UpvarPath,
754 pub closure_expr_id: LocalDefId,
757 #[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
758 pub enum BorrowKind {
759 /// Data must be immutable and is aliasable.
762 /// Data must be immutable but not aliasable. This kind of borrow
763 /// cannot currently be expressed by the user and is used only in
764 /// implicit closure bindings. It is needed when the closure
765 /// is borrowing or mutating a mutable referent, e.g.:
767 /// let x: &mut isize = ...;
768 /// let y = || *x += 5;
770 /// If we were to try to translate this closure into a more explicit
771 /// form, we'd encounter an error with the code as written:
773 /// struct Env { x: & &mut isize }
774 /// let x: &mut isize = ...;
775 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
776 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
778 /// This is then illegal because you cannot mutate a `&mut` found
779 /// in an aliasable location. To solve, you'd have to translate with
780 /// an `&mut` borrow:
782 /// struct Env { x: & &mut isize }
783 /// let x: &mut isize = ...;
784 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
785 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
787 /// Now the assignment to `**env.x` is legal, but creating a
788 /// mutable pointer to `x` is not because `x` is not mutable. We
789 /// could fix this by declaring `x` as `let mut x`. This is ok in
790 /// user code, if awkward, but extra weird for closures, since the
791 /// borrow is hidden.
793 /// So we introduce a "unique imm" borrow -- the referent is
794 /// immutable, but not aliasable. This solves the problem. For
795 /// simplicity, we don't give users the way to express this
796 /// borrow, it's just used when translating closures.
799 /// Data is mutable and not aliasable.
803 /// Information describing the capture of an upvar. This is computed
804 /// during `typeck`, specifically by `regionck`.
805 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
806 pub enum UpvarCapture<'tcx> {
807 /// Upvar is captured by value. This is always true when the
808 /// closure is labeled `move`, but can also be true in other cases
809 /// depending on inference.
812 /// Upvar is captured by reference.
813 ByRef(UpvarBorrow<'tcx>),
816 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
817 pub struct UpvarBorrow<'tcx> {
818 /// The kind of borrow: by-ref upvars have access to shared
819 /// immutable borrows, which are not part of the normal language
821 pub kind: BorrowKind,
823 /// Region of the resulting reference.
824 pub region: ty::Region<'tcx>,
827 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
828 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
830 #[derive(Copy, Clone)]
831 pub struct ClosureUpvar<'tcx> {
837 #[derive(Clone, Copy, PartialEq, Eq)]
838 pub enum IntVarValue {
840 UintType(ast::UintTy),
843 #[derive(Clone, Copy, PartialEq, Eq)]
844 pub struct FloatVarValue(pub ast::FloatTy);
846 impl ty::EarlyBoundRegion {
847 pub fn to_bound_region(&self) -> ty::BoundRegion {
848 ty::BoundRegion::BrNamed(self.def_id, self.name)
851 /// Does this early bound region have a name? Early bound regions normally
852 /// always have names except when using anonymous lifetimes (`'_`).
853 pub fn has_name(&self) -> bool {
854 self.name != kw::UnderscoreLifetime
858 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
859 pub enum GenericParamDefKind {
863 object_lifetime_default: ObjectLifetimeDefault,
864 synthetic: Option<hir::SyntheticTyParamKind>,
869 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
870 pub struct GenericParamDef {
875 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
876 /// on generic parameter `'a`/`T`, asserts data behind the parameter
877 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
878 pub pure_wrt_drop: bool,
880 pub kind: GenericParamDefKind,
883 impl GenericParamDef {
884 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
885 if let GenericParamDefKind::Lifetime = self.kind {
886 ty::EarlyBoundRegion {
892 bug!("cannot convert a non-lifetime parameter def to an early bound region")
896 pub fn to_bound_region(&self) -> ty::BoundRegion {
897 if let GenericParamDefKind::Lifetime = self.kind {
898 self.to_early_bound_region_data().to_bound_region()
900 bug!("cannot convert a non-lifetime parameter def to an early bound region")
906 pub struct GenericParamCount {
907 pub lifetimes: usize,
912 /// Information about the formal type/lifetime parameters associated
913 /// with an item or method. Analogous to `hir::Generics`.
915 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
916 /// `Self` (optionally), `Lifetime` params..., `Type` params...
917 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
918 pub struct Generics {
919 pub parent: Option<DefId>,
920 pub parent_count: usize,
921 pub params: Vec<GenericParamDef>,
923 /// Reverse map to the `index` field of each `GenericParamDef`.
924 #[stable_hasher(ignore)]
925 pub param_def_id_to_index: FxHashMap<DefId, u32>,
928 pub has_late_bound_regions: Option<Span>,
931 impl<'tcx> Generics {
932 pub fn count(&self) -> usize {
933 self.parent_count + self.params.len()
936 pub fn own_counts(&self) -> GenericParamCount {
937 // We could cache this as a property of `GenericParamCount`, but
938 // the aim is to refactor this away entirely eventually and the
939 // presence of this method will be a constant reminder.
940 let mut own_counts: GenericParamCount = Default::default();
942 for param in &self.params {
944 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
945 GenericParamDefKind::Type { .. } => own_counts.types += 1,
946 GenericParamDefKind::Const => own_counts.consts += 1,
953 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
954 if self.own_requires_monomorphization() {
958 if let Some(parent_def_id) = self.parent {
959 let parent = tcx.generics_of(parent_def_id);
960 parent.requires_monomorphization(tcx)
966 pub fn own_requires_monomorphization(&self) -> bool {
967 for param in &self.params {
969 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
970 GenericParamDefKind::Lifetime => {}
978 param: &EarlyBoundRegion,
980 ) -> &'tcx GenericParamDef {
981 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
982 let param = &self.params[index as usize];
984 GenericParamDefKind::Lifetime => param,
985 _ => bug!("expected lifetime parameter, but found another generic parameter")
988 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
989 .region_param(param, tcx)
993 /// Returns the `GenericParamDef` associated with this `ParamTy`.
994 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
995 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
996 let param = &self.params[index as usize];
998 GenericParamDefKind::Type { .. } => param,
999 _ => bug!("expected type parameter, but found another generic parameter")
1002 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
1003 .type_param(param, tcx)
1007 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
1008 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
1009 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
1010 let param = &self.params[index as usize];
1012 GenericParamDefKind::Const => param,
1013 _ => bug!("expected const parameter, but found another generic parameter")
1016 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1017 .const_param(param, tcx)
1022 /// Bounds on generics.
1023 #[derive(Copy, Clone, Default, Debug, RustcEncodable, RustcDecodable, HashStable)]
1024 pub struct GenericPredicates<'tcx> {
1025 pub parent: Option<DefId>,
1026 pub predicates: &'tcx [(Predicate<'tcx>, Span)],
1029 impl<'tcx> GenericPredicates<'tcx> {
1033 substs: SubstsRef<'tcx>,
1034 ) -> InstantiatedPredicates<'tcx> {
1035 let mut instantiated = InstantiatedPredicates::empty();
1036 self.instantiate_into(tcx, &mut instantiated, substs);
1040 pub fn instantiate_own(
1043 substs: SubstsRef<'tcx>,
1044 ) -> InstantiatedPredicates<'tcx> {
1045 InstantiatedPredicates {
1046 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1050 fn instantiate_into(
1053 instantiated: &mut InstantiatedPredicates<'tcx>,
1054 substs: SubstsRef<'tcx>,
1056 if let Some(def_id) = self.parent {
1057 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1059 instantiated.predicates.extend(
1060 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1064 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
1065 let mut instantiated = InstantiatedPredicates::empty();
1066 self.instantiate_identity_into(tcx, &mut instantiated);
1070 fn instantiate_identity_into(
1073 instantiated: &mut InstantiatedPredicates<'tcx>,
1075 if let Some(def_id) = self.parent {
1076 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1078 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1081 pub fn instantiate_supertrait(
1084 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1085 ) -> InstantiatedPredicates<'tcx> {
1086 assert_eq!(self.parent, None);
1087 InstantiatedPredicates {
1088 predicates: self.predicates.iter().map(|(pred, _)| {
1089 pred.subst_supertrait(tcx, poly_trait_ref)
1095 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1096 pub enum Predicate<'tcx> {
1097 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1098 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1099 /// would be the type parameters.
1100 Trait(PolyTraitPredicate<'tcx>),
1103 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1106 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1108 /// `where <T as TraitRef>::Name == X`, approximately.
1109 /// See the `ProjectionPredicate` struct for details.
1110 Projection(PolyProjectionPredicate<'tcx>),
1112 /// No syntax: `T` well-formed.
1113 WellFormed(Ty<'tcx>),
1115 /// Trait must be object-safe.
1118 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1119 /// for some substitutions `...` and `T` being a closure type.
1120 /// Satisfied (or refuted) once we know the closure's kind.
1121 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
1124 Subtype(PolySubtypePredicate<'tcx>),
1126 /// Constant initializer must evaluate successfully.
1127 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1130 /// The crate outlives map is computed during typeck and contains the
1131 /// outlives of every item in the local crate. You should not use it
1132 /// directly, because to do so will make your pass dependent on the
1133 /// HIR of every item in the local crate. Instead, use
1134 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1136 #[derive(HashStable)]
1137 pub struct CratePredicatesMap<'tcx> {
1138 /// For each struct with outlive bounds, maps to a vector of the
1139 /// predicate of its outlive bounds. If an item has no outlives
1140 /// bounds, it will have no entry.
1141 pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
1144 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1145 fn as_ref(&self) -> &Predicate<'tcx> {
1150 impl<'tcx> Predicate<'tcx> {
1151 /// Performs a substitution suitable for going from a
1152 /// poly-trait-ref to supertraits that must hold if that
1153 /// poly-trait-ref holds. This is slightly different from a normal
1154 /// substitution in terms of what happens with bound regions. See
1155 /// lengthy comment below for details.
1156 pub fn subst_supertrait(
1159 trait_ref: &ty::PolyTraitRef<'tcx>,
1160 ) -> ty::Predicate<'tcx> {
1161 // The interaction between HRTB and supertraits is not entirely
1162 // obvious. Let me walk you (and myself) through an example.
1164 // Let's start with an easy case. Consider two traits:
1166 // trait Foo<'a>: Bar<'a,'a> { }
1167 // trait Bar<'b,'c> { }
1169 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1170 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1171 // knew that `Foo<'x>` (for any 'x) then we also know that
1172 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1173 // normal substitution.
1175 // In terms of why this is sound, the idea is that whenever there
1176 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1177 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1178 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1181 // Another example to be careful of is this:
1183 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1184 // trait Bar1<'b,'c> { }
1186 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1187 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1188 // reason is similar to the previous example: any impl of
1189 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1190 // basically we would want to collapse the bound lifetimes from
1191 // the input (`trait_ref`) and the supertraits.
1193 // To achieve this in practice is fairly straightforward. Let's
1194 // consider the more complicated scenario:
1196 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1197 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1198 // where both `'x` and `'b` would have a DB index of 1.
1199 // The substitution from the input trait-ref is therefore going to be
1200 // `'a => 'x` (where `'x` has a DB index of 1).
1201 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1202 // early-bound parameter and `'b' is a late-bound parameter with a
1204 // - If we replace `'a` with `'x` from the input, it too will have
1205 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1206 // just as we wanted.
1208 // There is only one catch. If we just apply the substitution `'a
1209 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1210 // adjust the DB index because we substituting into a binder (it
1211 // tries to be so smart...) resulting in `for<'x> for<'b>
1212 // Bar1<'x,'b>` (we have no syntax for this, so use your
1213 // imagination). Basically the 'x will have DB index of 2 and 'b
1214 // will have DB index of 1. Not quite what we want. So we apply
1215 // the substitution to the *contents* of the trait reference,
1216 // rather than the trait reference itself (put another way, the
1217 // substitution code expects equal binding levels in the values
1218 // from the substitution and the value being substituted into, and
1219 // this trick achieves that).
1221 let substs = &trait_ref.skip_binder().substs;
1223 Predicate::Trait(ref binder) =>
1224 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1225 Predicate::Subtype(ref binder) =>
1226 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1227 Predicate::RegionOutlives(ref binder) =>
1228 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1229 Predicate::TypeOutlives(ref binder) =>
1230 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1231 Predicate::Projection(ref binder) =>
1232 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1233 Predicate::WellFormed(data) =>
1234 Predicate::WellFormed(data.subst(tcx, substs)),
1235 Predicate::ObjectSafe(trait_def_id) =>
1236 Predicate::ObjectSafe(trait_def_id),
1237 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1238 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1239 Predicate::ConstEvaluatable(def_id, const_substs) =>
1240 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1245 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1246 pub struct TraitPredicate<'tcx> {
1247 pub trait_ref: TraitRef<'tcx>
1250 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1252 impl<'tcx> TraitPredicate<'tcx> {
1253 pub fn def_id(&self) -> DefId {
1254 self.trait_ref.def_id
1257 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
1258 self.trait_ref.input_types()
1261 pub fn self_ty(&self) -> Ty<'tcx> {
1262 self.trait_ref.self_ty()
1266 impl<'tcx> PolyTraitPredicate<'tcx> {
1267 pub fn def_id(&self) -> DefId {
1268 // Ok to skip binder since trait `DefId` does not care about regions.
1269 self.skip_binder().def_id()
1273 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1274 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1275 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1276 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1277 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1278 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1279 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1280 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1282 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1283 pub struct SubtypePredicate<'tcx> {
1284 pub a_is_expected: bool,
1288 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1290 /// This kind of predicate has no *direct* correspondent in the
1291 /// syntax, but it roughly corresponds to the syntactic forms:
1293 /// 1. `T: TraitRef<..., Item = Type>`
1294 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1296 /// In particular, form #1 is "desugared" to the combination of a
1297 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1298 /// predicates. Form #2 is a broader form in that it also permits
1299 /// equality between arbitrary types. Processing an instance of
1300 /// Form #2 eventually yields one of these `ProjectionPredicate`
1301 /// instances to normalize the LHS.
1302 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1303 pub struct ProjectionPredicate<'tcx> {
1304 pub projection_ty: ProjectionTy<'tcx>,
1308 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1310 impl<'tcx> PolyProjectionPredicate<'tcx> {
1311 /// Returns the `DefId` of the associated item being projected.
1312 pub fn item_def_id(&self) -> DefId {
1313 self.skip_binder().projection_ty.item_def_id
1317 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_>) -> PolyTraitRef<'tcx> {
1318 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1319 // `self.0.trait_ref` is permitted to have escaping regions.
1320 // This is because here `self` has a `Binder` and so does our
1321 // return value, so we are preserving the number of binding
1323 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1326 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1327 self.map_bound(|predicate| predicate.ty)
1330 /// The `DefId` of the `TraitItem` for the associated type.
1332 /// Note that this is not the `DefId` of the `TraitRef` containing this
1333 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1334 pub fn projection_def_id(&self) -> DefId {
1335 // Ok to skip binder since trait `DefId` does not care about regions.
1336 self.skip_binder().projection_ty.item_def_id
1340 pub trait ToPolyTraitRef<'tcx> {
1341 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1344 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1345 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1346 ty::Binder::dummy(self.clone())
1350 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1351 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1352 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1356 pub trait ToPredicate<'tcx> {
1357 fn to_predicate(&self) -> Predicate<'tcx>;
1360 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1361 fn to_predicate(&self) -> Predicate<'tcx> {
1362 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1363 trait_ref: self.clone()
1368 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1369 fn to_predicate(&self) -> Predicate<'tcx> {
1370 ty::Predicate::Trait(self.to_poly_trait_predicate())
1374 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1375 fn to_predicate(&self) -> Predicate<'tcx> {
1376 Predicate::RegionOutlives(self.clone())
1380 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1381 fn to_predicate(&self) -> Predicate<'tcx> {
1382 Predicate::TypeOutlives(self.clone())
1386 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1387 fn to_predicate(&self) -> Predicate<'tcx> {
1388 Predicate::Projection(self.clone())
1392 // A custom iterator used by `Predicate::walk_tys`.
1393 enum WalkTysIter<'tcx, I, J, K>
1394 where I: Iterator<Item = Ty<'tcx>>,
1395 J: Iterator<Item = Ty<'tcx>>,
1396 K: Iterator<Item = Ty<'tcx>>
1400 Two(Ty<'tcx>, Ty<'tcx>),
1406 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1407 where I: Iterator<Item = Ty<'tcx>>,
1408 J: Iterator<Item = Ty<'tcx>>,
1409 K: Iterator<Item = Ty<'tcx>>
1411 type Item = Ty<'tcx>;
1413 fn next(&mut self) -> Option<Ty<'tcx>> {
1415 WalkTysIter::None => None,
1416 WalkTysIter::One(item) => {
1417 *self = WalkTysIter::None;
1420 WalkTysIter::Two(item1, item2) => {
1421 *self = WalkTysIter::One(item2);
1424 WalkTysIter::Types(ref mut iter) => {
1427 WalkTysIter::InputTypes(ref mut iter) => {
1430 WalkTysIter::ProjectionTypes(ref mut iter) => {
1437 impl<'tcx> Predicate<'tcx> {
1438 /// Iterates over the types in this predicate. Note that in all
1439 /// cases this is skipping over a binder, so late-bound regions
1440 /// with depth 0 are bound by the predicate.
1441 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1443 ty::Predicate::Trait(ref data) => {
1444 WalkTysIter::InputTypes(data.skip_binder().input_types())
1446 ty::Predicate::Subtype(binder) => {
1447 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1448 WalkTysIter::Two(a, b)
1450 ty::Predicate::TypeOutlives(binder) => {
1451 WalkTysIter::One(binder.skip_binder().0)
1453 ty::Predicate::RegionOutlives(..) => {
1456 ty::Predicate::Projection(ref data) => {
1457 let inner = data.skip_binder();
1458 WalkTysIter::ProjectionTypes(
1459 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1461 ty::Predicate::WellFormed(data) => {
1462 WalkTysIter::One(data)
1464 ty::Predicate::ObjectSafe(_trait_def_id) => {
1467 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1468 WalkTysIter::Types(closure_substs.types())
1470 ty::Predicate::ConstEvaluatable(_, substs) => {
1471 WalkTysIter::Types(substs.types())
1476 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1478 Predicate::Trait(ref t) => {
1479 Some(t.to_poly_trait_ref())
1481 Predicate::Projection(..) |
1482 Predicate::Subtype(..) |
1483 Predicate::RegionOutlives(..) |
1484 Predicate::WellFormed(..) |
1485 Predicate::ObjectSafe(..) |
1486 Predicate::ClosureKind(..) |
1487 Predicate::TypeOutlives(..) |
1488 Predicate::ConstEvaluatable(..) => {
1494 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1496 Predicate::TypeOutlives(data) => {
1499 Predicate::Trait(..) |
1500 Predicate::Projection(..) |
1501 Predicate::Subtype(..) |
1502 Predicate::RegionOutlives(..) |
1503 Predicate::WellFormed(..) |
1504 Predicate::ObjectSafe(..) |
1505 Predicate::ClosureKind(..) |
1506 Predicate::ConstEvaluatable(..) => {
1513 /// Represents the bounds declared on a particular set of type
1514 /// parameters. Should eventually be generalized into a flag list of
1515 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1516 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1517 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1518 /// the `GenericPredicates` are expressed in terms of the bound type
1519 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1520 /// represented a set of bounds for some particular instantiation,
1521 /// meaning that the generic parameters have been substituted with
1526 /// struct Foo<T, U: Bar<T>> { ... }
1528 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1529 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1530 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1531 /// [usize:Bar<isize>]]`.
1532 #[derive(Clone, Debug)]
1533 pub struct InstantiatedPredicates<'tcx> {
1534 pub predicates: Vec<Predicate<'tcx>>,
1537 impl<'tcx> InstantiatedPredicates<'tcx> {
1538 pub fn empty() -> InstantiatedPredicates<'tcx> {
1539 InstantiatedPredicates { predicates: vec![] }
1542 pub fn is_empty(&self) -> bool {
1543 self.predicates.is_empty()
1547 rustc_index::newtype_index! {
1548 /// "Universes" are used during type- and trait-checking in the
1549 /// presence of `for<..>` binders to control what sets of names are
1550 /// visible. Universes are arranged into a tree: the root universe
1551 /// contains names that are always visible. Each child then adds a new
1552 /// set of names that are visible, in addition to those of its parent.
1553 /// We say that the child universe "extends" the parent universe with
1556 /// To make this more concrete, consider this program:
1560 /// fn bar<T>(x: T) {
1561 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1565 /// The struct name `Foo` is in the root universe U0. But the type
1566 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1567 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1568 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1569 /// region `'a` is in a universe U2 that extends U1, because we can
1570 /// name it inside the fn type but not outside.
1572 /// Universes are used to do type- and trait-checking around these
1573 /// "forall" binders (also called **universal quantification**). The
1574 /// idea is that when, in the body of `bar`, we refer to `T` as a
1575 /// type, we aren't referring to any type in particular, but rather a
1576 /// kind of "fresh" type that is distinct from all other types we have
1577 /// actually declared. This is called a **placeholder** type, and we
1578 /// use universes to talk about this. In other words, a type name in
1579 /// universe 0 always corresponds to some "ground" type that the user
1580 /// declared, but a type name in a non-zero universe is a placeholder
1581 /// type -- an idealized representative of "types in general" that we
1582 /// use for checking generic functions.
1583 pub struct UniverseIndex {
1584 DEBUG_FORMAT = "U{}",
1588 impl_stable_hash_for!(struct UniverseIndex { private });
1590 impl UniverseIndex {
1591 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1593 /// Returns the "next" universe index in order -- this new index
1594 /// is considered to extend all previous universes. This
1595 /// corresponds to entering a `forall` quantifier. So, for
1596 /// example, suppose we have this type in universe `U`:
1599 /// for<'a> fn(&'a u32)
1602 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1603 /// new universe that extends `U` -- in this new universe, we can
1604 /// name the region `'a`, but that region was not nameable from
1605 /// `U` because it was not in scope there.
1606 pub fn next_universe(self) -> UniverseIndex {
1607 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1610 /// Returns `true` if `self` can name a name from `other` -- in other words,
1611 /// if the set of names in `self` is a superset of those in
1612 /// `other` (`self >= other`).
1613 pub fn can_name(self, other: UniverseIndex) -> bool {
1614 self.private >= other.private
1617 /// Returns `true` if `self` cannot name some names from `other` -- in other
1618 /// words, if the set of names in `self` is a strict subset of
1619 /// those in `other` (`self < other`).
1620 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1621 self.private < other.private
1625 /// The "placeholder index" fully defines a placeholder region.
1626 /// Placeholder regions are identified by both a **universe** as well
1627 /// as a "bound-region" within that universe. The `bound_region` is
1628 /// basically a name -- distinct bound regions within the same
1629 /// universe are just two regions with an unknown relationship to one
1631 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1632 pub struct Placeholder<T> {
1633 pub universe: UniverseIndex,
1637 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1639 T: HashStable<StableHashingContext<'a>>,
1641 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1642 self.universe.hash_stable(hcx, hasher);
1643 self.name.hash_stable(hcx, hasher);
1647 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1649 pub type PlaceholderType = Placeholder<BoundVar>;
1651 pub type PlaceholderConst = Placeholder<BoundVar>;
1653 /// When type checking, we use the `ParamEnv` to track
1654 /// details about the set of where-clauses that are in scope at this
1655 /// particular point.
1656 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1657 pub struct ParamEnv<'tcx> {
1658 /// `Obligation`s that the caller must satisfy. This is basically
1659 /// the set of bounds on the in-scope type parameters, translated
1660 /// into `Obligation`s, and elaborated and normalized.
1661 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1663 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1664 /// want `Reveal::All` -- note that this is always paired with an
1665 /// empty environment. To get that, use `ParamEnv::reveal()`.
1666 pub reveal: traits::Reveal,
1668 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1669 /// register that `def_id` (useful for transitioning to the chalk trait
1671 pub def_id: Option<DefId>,
1674 impl<'tcx> ParamEnv<'tcx> {
1675 /// Construct a trait environment suitable for contexts where
1676 /// there are no where-clauses in scope. Hidden types (like `impl
1677 /// Trait`) are left hidden, so this is suitable for ordinary
1680 pub fn empty() -> Self {
1681 Self::new(List::empty(), Reveal::UserFacing, None)
1684 /// Construct a trait environment with no where-clauses in scope
1685 /// where the values of all `impl Trait` and other hidden types
1686 /// are revealed. This is suitable for monomorphized, post-typeck
1687 /// environments like codegen or doing optimizations.
1689 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1690 /// or invoke `param_env.with_reveal_all()`.
1692 pub fn reveal_all() -> Self {
1693 Self::new(List::empty(), Reveal::All, None)
1696 /// Construct a trait environment with the given set of predicates.
1699 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1701 def_id: Option<DefId>
1703 ty::ParamEnv { caller_bounds, reveal, def_id }
1706 /// Returns a new parameter environment with the same clauses, but
1707 /// which "reveals" the true results of projections in all cases
1708 /// (even for associated types that are specializable). This is
1709 /// the desired behavior during codegen and certain other special
1710 /// contexts; normally though we want to use `Reveal::UserFacing`,
1711 /// which is the default.
1712 pub fn with_reveal_all(self) -> Self {
1713 ty::ParamEnv { reveal: Reveal::All, ..self }
1716 /// Returns this same environment but with no caller bounds.
1717 pub fn without_caller_bounds(self) -> Self {
1718 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1721 /// Creates a suitable environment in which to perform trait
1722 /// queries on the given value. When type-checking, this is simply
1723 /// the pair of the environment plus value. But when reveal is set to
1724 /// All, then if `value` does not reference any type parameters, we will
1725 /// pair it with the empty environment. This improves caching and is generally
1728 /// N.B., we preserve the environment when type-checking because it
1729 /// is possible for the user to have wacky where-clauses like
1730 /// `where Box<u32>: Copy`, which are clearly never
1731 /// satisfiable. We generally want to behave as if they were true,
1732 /// although the surrounding function is never reachable.
1733 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1735 Reveal::UserFacing => {
1743 if value.has_placeholders()
1744 || value.needs_infer()
1745 || value.has_param_types()
1753 param_env: self.without_caller_bounds(),
1762 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1763 pub struct ParamEnvAnd<'tcx, T> {
1764 pub param_env: ParamEnv<'tcx>,
1768 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1769 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1770 (self.param_env, self.value)
1774 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1776 T: HashStable<StableHashingContext<'a>>,
1778 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1784 param_env.hash_stable(hcx, hasher);
1785 value.hash_stable(hcx, hasher);
1789 #[derive(Copy, Clone, Debug, HashStable)]
1790 pub struct Destructor {
1791 /// The `DefId` of the destructor method
1796 #[derive(HashStable)]
1797 pub struct AdtFlags: u32 {
1798 const NO_ADT_FLAGS = 0;
1799 /// Indicates whether the ADT is an enum.
1800 const IS_ENUM = 1 << 0;
1801 /// Indicates whether the ADT is a union.
1802 const IS_UNION = 1 << 1;
1803 /// Indicates whether the ADT is a struct.
1804 const IS_STRUCT = 1 << 2;
1805 /// Indicates whether the ADT is a struct and has a constructor.
1806 const HAS_CTOR = 1 << 3;
1807 /// Indicates whether the type is a `PhantomData`.
1808 const IS_PHANTOM_DATA = 1 << 4;
1809 /// Indicates whether the type has a `#[fundamental]` attribute.
1810 const IS_FUNDAMENTAL = 1 << 5;
1811 /// Indicates whether the type is a `Box`.
1812 const IS_BOX = 1 << 6;
1813 /// Indicates whether the type is an `Arc`.
1814 const IS_ARC = 1 << 7;
1815 /// Indicates whether the type is an `Rc`.
1816 const IS_RC = 1 << 8;
1817 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1818 /// (i.e., this flag is never set unless this ADT is an enum).
1819 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1824 #[derive(HashStable)]
1825 pub struct VariantFlags: u32 {
1826 const NO_VARIANT_FLAGS = 0;
1827 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1828 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1832 /// Definition of a variant -- a struct's fields or a enum variant.
1834 pub struct VariantDef {
1835 /// `DefId` that identifies the variant itself.
1836 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1838 /// `DefId` that identifies the variant's constructor.
1839 /// If this variant is a struct variant, then this is `None`.
1840 pub ctor_def_id: Option<DefId>,
1841 /// Variant or struct name.
1843 /// Discriminant of this variant.
1844 pub discr: VariantDiscr,
1845 /// Fields of this variant.
1846 pub fields: Vec<FieldDef>,
1847 /// Type of constructor of variant.
1848 pub ctor_kind: CtorKind,
1849 /// Flags of the variant (e.g. is field list non-exhaustive)?
1850 flags: VariantFlags,
1851 /// Variant is obtained as part of recovering from a syntactic error.
1852 /// May be incomplete or bogus.
1853 pub recovered: bool,
1856 impl<'tcx> VariantDef {
1857 /// Creates a new `VariantDef`.
1859 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1860 /// represents an enum variant).
1862 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1863 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1865 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1866 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1867 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1868 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1869 /// built-in trait), and we do not want to load attributes twice.
1871 /// If someone speeds up attribute loading to not be a performance concern, they can
1872 /// remove this hack and use the constructor `DefId` everywhere.
1876 variant_did: Option<DefId>,
1877 ctor_def_id: Option<DefId>,
1878 discr: VariantDiscr,
1879 fields: Vec<FieldDef>,
1880 ctor_kind: CtorKind,
1886 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1887 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1888 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1891 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1892 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1893 debug!("found non-exhaustive field list for {:?}", parent_did);
1894 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1895 } else if let Some(variant_did) = variant_did {
1896 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1897 debug!("found non-exhaustive field list for {:?}", variant_did);
1898 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1903 def_id: variant_did.unwrap_or(parent_did),
1914 /// Is this field list non-exhaustive?
1916 pub fn is_field_list_non_exhaustive(&self) -> bool {
1917 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1921 impl_stable_hash_for!(struct VariantDef {
1924 ident -> (ident.name),
1932 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1933 pub enum VariantDiscr {
1934 /// Explicit value for this variant, i.e., `X = 123`.
1935 /// The `DefId` corresponds to the embedded constant.
1938 /// The previous variant's discriminant plus one.
1939 /// For efficiency reasons, the distance from the
1940 /// last `Explicit` discriminant is being stored,
1941 /// or `0` for the first variant, if it has none.
1945 #[derive(Debug, HashStable)]
1946 pub struct FieldDef {
1948 #[stable_hasher(project(name))]
1950 pub vis: Visibility,
1953 /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
1955 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1957 /// The initialism *"Adt"* stands for an [*algebraic data type (ADT)*][adt].
1958 /// This is slightly wrong because `union`s are not ADTs.
1959 /// Moreover, Rust only allows recursive data types through indirection.
1961 /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
1963 /// `DefId` of the struct, enum or union item.
1965 /// Variants of the ADT. If this is a struct or union, then there will be a single variant.
1966 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1967 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1969 /// Repr options provided by the user.
1970 pub repr: ReprOptions,
1973 impl PartialOrd for AdtDef {
1974 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1975 Some(self.cmp(&other))
1979 /// There should be only one AdtDef for each `did`, therefore
1980 /// it is fine to implement `Ord` only based on `did`.
1981 impl Ord for AdtDef {
1982 fn cmp(&self, other: &AdtDef) -> Ordering {
1983 self.did.cmp(&other.did)
1987 impl PartialEq for AdtDef {
1988 // AdtDef are always interned and this is part of TyS equality
1990 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1993 impl Eq for AdtDef {}
1995 impl Hash for AdtDef {
1997 fn hash<H: Hasher>(&self, s: &mut H) {
1998 (self as *const AdtDef).hash(s)
2002 impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef {
2003 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
2008 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {}
2011 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
2012 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
2014 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
2017 let hash: Fingerprint = CACHE.with(|cache| {
2018 let addr = self as *const AdtDef as usize;
2019 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2027 let mut hasher = StableHasher::new();
2028 did.hash_stable(hcx, &mut hasher);
2029 variants.hash_stable(hcx, &mut hasher);
2030 flags.hash_stable(hcx, &mut hasher);
2031 repr.hash_stable(hcx, &mut hasher);
2037 hash.hash_stable(hcx, hasher);
2041 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2042 pub enum AdtKind { Struct, Union, Enum }
2044 impl Into<DataTypeKind> for AdtKind {
2045 fn into(self) -> DataTypeKind {
2047 AdtKind::Struct => DataTypeKind::Struct,
2048 AdtKind::Union => DataTypeKind::Union,
2049 AdtKind::Enum => DataTypeKind::Enum,
2055 #[derive(RustcEncodable, RustcDecodable, Default)]
2056 pub struct ReprFlags: u8 {
2057 const IS_C = 1 << 0;
2058 const IS_SIMD = 1 << 1;
2059 const IS_TRANSPARENT = 1 << 2;
2060 // Internal only for now. If true, don't reorder fields.
2061 const IS_LINEAR = 1 << 3;
2063 // Any of these flags being set prevent field reordering optimisation.
2064 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2065 ReprFlags::IS_SIMD.bits |
2066 ReprFlags::IS_LINEAR.bits;
2070 impl_stable_hash_for!(struct ReprFlags {
2074 /// Represents the repr options provided by the user,
2075 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2076 pub struct ReprOptions {
2077 pub int: Option<attr::IntType>,
2078 pub align: Option<Align>,
2079 pub pack: Option<Align>,
2080 pub flags: ReprFlags,
2083 impl_stable_hash_for!(struct ReprOptions {
2091 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2092 let mut flags = ReprFlags::empty();
2093 let mut size = None;
2094 let mut max_align: Option<Align> = None;
2095 let mut min_pack: Option<Align> = None;
2096 for attr in tcx.get_attrs(did).iter() {
2097 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2098 flags.insert(match r {
2099 attr::ReprC => ReprFlags::IS_C,
2100 attr::ReprPacked(pack) => {
2101 let pack = Align::from_bytes(pack as u64).unwrap();
2102 min_pack = Some(if let Some(min_pack) = min_pack {
2109 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2110 attr::ReprSimd => ReprFlags::IS_SIMD,
2111 attr::ReprInt(i) => {
2115 attr::ReprAlign(align) => {
2116 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2123 // This is here instead of layout because the choice must make it into metadata.
2124 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2125 flags.insert(ReprFlags::IS_LINEAR);
2127 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2131 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2133 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2135 pub fn packed(&self) -> bool { self.pack.is_some() }
2137 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2139 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2141 pub fn discr_type(&self) -> attr::IntType {
2142 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2145 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2146 /// layout" optimizations, such as representing `Foo<&T>` as a
2148 pub fn inhibit_enum_layout_opt(&self) -> bool {
2149 self.c() || self.int.is_some()
2152 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2153 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2154 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2155 if let Some(pack) = self.pack {
2156 if pack.bytes() == 1 {
2160 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2163 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2164 pub fn inhibit_union_abi_opt(&self) -> bool {
2170 /// Creates a new `AdtDef`.
2175 variants: IndexVec<VariantIdx, VariantDef>,
2178 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2179 let mut flags = AdtFlags::NO_ADT_FLAGS;
2181 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2182 debug!("found non-exhaustive variant list for {:?}", did);
2183 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2186 flags |= match kind {
2187 AdtKind::Enum => AdtFlags::IS_ENUM,
2188 AdtKind::Union => AdtFlags::IS_UNION,
2189 AdtKind::Struct => AdtFlags::IS_STRUCT,
2192 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2193 flags |= AdtFlags::HAS_CTOR;
2196 let attrs = tcx.get_attrs(did);
2197 if attr::contains_name(&attrs, sym::fundamental) {
2198 flags |= AdtFlags::IS_FUNDAMENTAL;
2200 if Some(did) == tcx.lang_items().phantom_data() {
2201 flags |= AdtFlags::IS_PHANTOM_DATA;
2203 if Some(did) == tcx.lang_items().owned_box() {
2204 flags |= AdtFlags::IS_BOX;
2206 if Some(did) == tcx.lang_items().arc() {
2207 flags |= AdtFlags::IS_ARC;
2209 if Some(did) == tcx.lang_items().rc() {
2210 flags |= AdtFlags::IS_RC;
2221 /// Returns `true` if this is a struct.
2223 pub fn is_struct(&self) -> bool {
2224 self.flags.contains(AdtFlags::IS_STRUCT)
2227 /// Returns `true` if this is a union.
2229 pub fn is_union(&self) -> bool {
2230 self.flags.contains(AdtFlags::IS_UNION)
2233 /// Returns `true` if this is a enum.
2235 pub fn is_enum(&self) -> bool {
2236 self.flags.contains(AdtFlags::IS_ENUM)
2239 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2241 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2242 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2245 /// Returns the kind of the ADT.
2247 pub fn adt_kind(&self) -> AdtKind {
2250 } else if self.is_union() {
2257 /// Returns a description of this abstract data type.
2258 pub fn descr(&self) -> &'static str {
2259 match self.adt_kind() {
2260 AdtKind::Struct => "struct",
2261 AdtKind::Union => "union",
2262 AdtKind::Enum => "enum",
2266 /// Returns a description of a variant of this abstract data type.
2268 pub fn variant_descr(&self) -> &'static str {
2269 match self.adt_kind() {
2270 AdtKind::Struct => "struct",
2271 AdtKind::Union => "union",
2272 AdtKind::Enum => "variant",
2276 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2278 pub fn has_ctor(&self) -> bool {
2279 self.flags.contains(AdtFlags::HAS_CTOR)
2282 /// Returns `true` if this type is `#[fundamental]` for the purposes
2283 /// of coherence checking.
2285 pub fn is_fundamental(&self) -> bool {
2286 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2289 /// Returns `true` if this is `PhantomData<T>`.
2291 pub fn is_phantom_data(&self) -> bool {
2292 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2295 /// Returns `true` if this is `Arc<T>`.
2296 pub fn is_arc(&self) -> bool {
2297 self.flags.contains(AdtFlags::IS_ARC)
2300 /// Returns `true` if this is `Rc<T>`.
2301 pub fn is_rc(&self) -> bool {
2302 self.flags.contains(AdtFlags::IS_RC)
2305 /// Returns `true` if this is Box<T>.
2307 pub fn is_box(&self) -> bool {
2308 self.flags.contains(AdtFlags::IS_BOX)
2311 /// Returns `true` if this type has a destructor.
2312 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2313 self.destructor(tcx).is_some()
2316 /// Asserts this is a struct or union and returns its unique variant.
2317 pub fn non_enum_variant(&self) -> &VariantDef {
2318 assert!(self.is_struct() || self.is_union());
2319 &self.variants[VariantIdx::new(0)]
2323 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> {
2324 tcx.predicates_of(self.did)
2327 /// Returns an iterator over all fields contained
2330 pub fn all_fields(&self) -> impl Iterator<Item=&FieldDef> + Clone {
2331 self.variants.iter().flat_map(|v| v.fields.iter())
2334 pub fn is_payloadfree(&self) -> bool {
2335 !self.variants.is_empty() &&
2336 self.variants.iter().all(|v| v.fields.is_empty())
2339 /// Return a `VariantDef` given a variant id.
2340 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2341 self.variants.iter().find(|v| v.def_id == vid)
2342 .expect("variant_with_id: unknown variant")
2345 /// Return a `VariantDef` given a constructor id.
2346 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2347 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2348 .expect("variant_with_ctor_id: unknown variant")
2351 /// Return the index of `VariantDef` given a variant id.
2352 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2353 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2354 .expect("variant_index_with_id: unknown variant").0
2357 /// Return the index of `VariantDef` given a constructor id.
2358 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2359 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2360 .expect("variant_index_with_ctor_id: unknown variant").0
2363 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2365 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2366 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2367 Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
2368 Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) |
2369 Res::SelfCtor(..) => self.non_enum_variant(),
2370 _ => bug!("unexpected res {:?} in variant_of_res", res)
2375 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2376 let param_env = tcx.param_env(expr_did);
2377 let repr_type = self.repr.discr_type();
2378 let substs = InternalSubsts::identity_for_item(tcx, expr_did);
2379 let instance = ty::Instance::new(expr_did, substs);
2380 let cid = GlobalId {
2384 match tcx.const_eval(param_env.and(cid)) {
2386 // FIXME: Find the right type and use it instead of `val.ty` here
2387 if let Some(b) = val.try_eval_bits(tcx, param_env, val.ty) {
2388 trace!("discriminants: {} ({:?})", b, repr_type);
2394 info!("invalid enum discriminant: {:#?}", val);
2395 crate::mir::interpret::struct_error(
2396 tcx.at(tcx.def_span(expr_did)),
2397 "constant evaluation of enum discriminant resulted in non-integer",
2402 Err(ErrorHandled::Reported) => {
2403 if !expr_did.is_local() {
2404 span_bug!(tcx.def_span(expr_did),
2405 "variant discriminant evaluation succeeded \
2406 in its crate but failed locally");
2410 Err(ErrorHandled::TooGeneric) => span_bug!(
2411 tcx.def_span(expr_did),
2412 "enum discriminant depends on generic arguments",
2418 pub fn discriminants(
2421 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2422 let repr_type = self.repr.discr_type();
2423 let initial = repr_type.initial_discriminant(tcx);
2424 let mut prev_discr = None::<Discr<'tcx>>;
2425 self.variants.iter_enumerated().map(move |(i, v)| {
2426 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2427 if let VariantDiscr::Explicit(expr_did) = v.discr {
2428 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2432 prev_discr = Some(discr);
2439 pub fn variant_range(&self) -> Range<VariantIdx> {
2440 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2443 /// Computes the discriminant value used by a specific variant.
2444 /// Unlike `discriminants`, this is (amortized) constant-time,
2445 /// only doing at most one query for evaluating an explicit
2446 /// discriminant (the last one before the requested variant),
2447 /// assuming there are no constant-evaluation errors there.
2449 pub fn discriminant_for_variant(
2452 variant_index: VariantIdx,
2454 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2455 let explicit_value = val
2456 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2457 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
2458 explicit_value.checked_add(tcx, offset as u128).0
2461 /// Yields a `DefId` for the discriminant and an offset to add to it
2462 /// Alternatively, if there is no explicit discriminant, returns the
2463 /// inferred discriminant directly.
2464 pub fn discriminant_def_for_variant(
2466 variant_index: VariantIdx,
2467 ) -> (Option<DefId>, u32) {
2468 let mut explicit_index = variant_index.as_u32();
2471 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2472 ty::VariantDiscr::Relative(0) => {
2476 ty::VariantDiscr::Relative(distance) => {
2477 explicit_index -= distance;
2479 ty::VariantDiscr::Explicit(did) => {
2480 expr_did = Some(did);
2485 (expr_did, variant_index.as_u32() - explicit_index)
2488 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2489 tcx.adt_destructor(self.did)
2492 /// Returns a list of types such that `Self: Sized` if and only
2493 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2495 /// Oddly enough, checking that the sized-constraint is `Sized` is
2496 /// actually more expressive than checking all members:
2497 /// the `Sized` trait is inductive, so an associated type that references
2498 /// `Self` would prevent its containing ADT from being `Sized`.
2500 /// Due to normalization being eager, this applies even if
2501 /// the associated type is behind a pointer (e.g., issue #31299).
2502 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2503 tcx.adt_sized_constraint(self.did).0
2506 fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> {
2507 let result = match ty.kind {
2508 Bool | Char | Int(..) | Uint(..) | Float(..) |
2509 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2510 Array(..) | Closure(..) | Generator(..) | Never => {
2519 GeneratorWitness(..) => {
2520 // these are never sized - return the target type
2527 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2531 Adt(adt, substs) => {
2533 let adt_tys = adt.sized_constraint(tcx);
2534 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2537 .map(|ty| ty.subst(tcx, substs))
2538 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2542 Projection(..) | Opaque(..) => {
2543 // must calculate explicitly.
2544 // FIXME: consider special-casing always-Sized projections
2548 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2551 // perf hack: if there is a `T: Sized` bound, then
2552 // we know that `T` is Sized and do not need to check
2555 let sized_trait = match tcx.lang_items().sized_trait() {
2557 _ => return vec![ty]
2559 let sized_predicate = Binder::dummy(TraitRef {
2560 def_id: sized_trait,
2561 substs: tcx.mk_substs_trait(ty, &[])
2563 let predicates = tcx.predicates_of(self.did).predicates;
2564 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2574 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2578 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2583 impl<'tcx> FieldDef {
2584 /// Returns the type of this field. The `subst` is typically obtained
2585 /// via the second field of `TyKind::AdtDef`.
2586 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2587 tcx.type_of(self.did).subst(tcx, subst)
2591 /// Represents the various closure traits in the language. This
2592 /// will determine the type of the environment (`self`, in the
2593 /// desugaring) argument that the closure expects.
2595 /// You can get the environment type of a closure using
2596 /// `tcx.closure_env_ty()`.
2597 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2598 RustcEncodable, RustcDecodable, HashStable)]
2599 pub enum ClosureKind {
2600 // Warning: Ordering is significant here! The ordering is chosen
2601 // because the trait Fn is a subtrait of FnMut and so in turn, and
2602 // hence we order it so that Fn < FnMut < FnOnce.
2608 impl<'tcx> ClosureKind {
2609 // This is the initial value used when doing upvar inference.
2610 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2612 pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
2614 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem, None),
2615 ClosureKind::FnMut => {
2616 tcx.require_lang_item(FnMutTraitLangItem, None)
2618 ClosureKind::FnOnce => {
2619 tcx.require_lang_item(FnOnceTraitLangItem, None)
2624 /// Returns `true` if this a type that impls this closure kind
2625 /// must also implement `other`.
2626 pub fn extends(self, other: ty::ClosureKind) -> bool {
2627 match (self, other) {
2628 (ClosureKind::Fn, ClosureKind::Fn) => true,
2629 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2630 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2631 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2632 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2633 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2638 /// Returns the representative scalar type for this closure kind.
2639 /// See `TyS::to_opt_closure_kind` for more details.
2640 pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
2642 ty::ClosureKind::Fn => tcx.types.i8,
2643 ty::ClosureKind::FnMut => tcx.types.i16,
2644 ty::ClosureKind::FnOnce => tcx.types.i32,
2649 impl<'tcx> TyS<'tcx> {
2650 /// Iterator that walks `self` and any types reachable from
2651 /// `self`, in depth-first order. Note that just walks the types
2652 /// that appear in `self`, it does not descend into the fields of
2653 /// structs or variants. For example:
2656 /// isize => { isize }
2657 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2658 /// [isize] => { [isize], isize }
2660 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2661 TypeWalker::new(self)
2664 /// Iterator that walks the immediate children of `self`. Hence
2665 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2666 /// (but not `i32`, like `walk`).
2667 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2668 walk::walk_shallow(self)
2671 /// Walks `ty` and any types appearing within `ty`, invoking the
2672 /// callback `f` on each type. If the callback returns `false`, then the
2673 /// children of the current type are ignored.
2675 /// Note: prefer `ty.walk()` where possible.
2676 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2677 where F: FnMut(Ty<'tcx>) -> bool
2679 let mut walker = self.walk();
2680 while let Some(ty) = walker.next() {
2682 walker.skip_current_subtree();
2689 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2691 hir::MutMutable => MutBorrow,
2692 hir::MutImmutable => ImmBorrow,
2696 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2697 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2698 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2700 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2702 MutBorrow => hir::MutMutable,
2703 ImmBorrow => hir::MutImmutable,
2705 // We have no type corresponding to a unique imm borrow, so
2706 // use `&mut`. It gives all the capabilities of an `&uniq`
2707 // and hence is a safe "over approximation".
2708 UniqueImmBorrow => hir::MutMutable,
2712 pub fn to_user_str(&self) -> &'static str {
2714 MutBorrow => "mutable",
2715 ImmBorrow => "immutable",
2716 UniqueImmBorrow => "uniquely immutable",
2721 #[derive(Debug, Clone)]
2722 pub enum Attributes<'tcx> {
2723 Owned(Lrc<[ast::Attribute]>),
2724 Borrowed(&'tcx [ast::Attribute]),
2727 impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
2728 type Target = [ast::Attribute];
2730 fn deref(&self) -> &[ast::Attribute] {
2732 &Attributes::Owned(ref data) => &data,
2733 &Attributes::Borrowed(data) => data
2738 #[derive(Debug, PartialEq, Eq)]
2739 pub enum ImplOverlapKind {
2740 /// These impls are always allowed to overlap.
2742 /// These impls are allowed to overlap, but that raises
2743 /// an issue #33140 future-compatibility warning.
2745 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2746 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2748 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2749 /// that difference, making what reduces to the following set of impls:
2753 /// impl Trait for dyn Send + Sync {}
2754 /// impl Trait for dyn Sync + Send {}
2757 /// Obviously, once we made these types be identical, that code causes a coherence
2758 /// error and a fairly big headache for us. However, luckily for us, the trait
2759 /// `Trait` used in this case is basically a marker trait, and therefore having
2760 /// overlapping impls for it is sound.
2762 /// To handle this, we basically regard the trait as a marker trait, with an additional
2763 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2764 /// it has the following restrictions:
2766 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2768 /// 2. The trait-ref of both impls must be equal.
2769 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2771 /// 4. Neither of the impls can have any where-clauses.
2773 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2777 impl<'tcx> TyCtxt<'tcx> {
2778 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
2779 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2782 /// Returns an iterator of the `DefId`s for all body-owners in this
2783 /// crate. If you would prefer to iterate over the bodies
2784 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2785 pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
2789 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2792 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2793 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2794 f(self.hir().body_owner_def_id(body_id))
2798 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
2799 self.associated_items(id)
2800 .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
2804 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2805 self.associated_items(did).any(|item| {
2806 item.relevant_for_never()
2810 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
2811 self.hir().as_local_hir_id(def_id).and_then(|hir_id| self.hir().get(hir_id).ident())
2814 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
2815 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2816 match self.hir().get(hir_id) {
2817 Node::TraitItem(_) | Node::ImplItem(_) => true,
2821 match self.def_kind(def_id).expect("no def for `DefId`") {
2824 | DefKind::AssocTy => true,
2829 if is_associated_item {
2830 Some(self.associated_item(def_id))
2836 fn associated_item_from_trait_item_ref(self,
2837 parent_def_id: DefId,
2838 parent_vis: &hir::Visibility,
2839 trait_item_ref: &hir::TraitItemRef)
2841 let def_id = self.hir().local_def_id(trait_item_ref.id.hir_id);
2842 let (kind, has_self) = match trait_item_ref.kind {
2843 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2844 hir::AssocItemKind::Method { has_self } => {
2845 (ty::AssocKind::Method, has_self)
2847 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2848 hir::AssocItemKind::OpaqueTy => bug!("only impls can have opaque types"),
2852 ident: trait_item_ref.ident,
2854 // Visibility of trait items is inherited from their traits.
2855 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2856 defaultness: trait_item_ref.defaultness,
2858 container: TraitContainer(parent_def_id),
2859 method_has_self_argument: has_self
2863 fn associated_item_from_impl_item_ref(self,
2864 parent_def_id: DefId,
2865 impl_item_ref: &hir::ImplItemRef)
2867 let def_id = self.hir().local_def_id(impl_item_ref.id.hir_id);
2868 let (kind, has_self) = match impl_item_ref.kind {
2869 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2870 hir::AssocItemKind::Method { has_self } => {
2871 (ty::AssocKind::Method, has_self)
2873 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2874 hir::AssocItemKind::OpaqueTy => (ty::AssocKind::OpaqueTy, false),
2878 ident: impl_item_ref.ident,
2880 // Visibility of trait impl items doesn't matter.
2881 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2882 defaultness: impl_item_ref.defaultness,
2884 container: ImplContainer(parent_def_id),
2885 method_has_self_argument: has_self
2889 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2890 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2893 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2894 variant.fields.iter().position(|field| {
2895 self.hygienic_eq(ident, field.ident, variant.def_id)
2899 pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
2900 // Ideally, we would use `-> impl Iterator` here, but it falls
2901 // afoul of the conservative "capture [restrictions]" we put
2902 // in place, so we use a hand-written iterator.
2904 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2905 AssocItemsIterator {
2907 def_ids: self.associated_item_def_ids(def_id),
2912 /// Returns `true` if the impls are the same polarity and the trait either
2913 /// has no items or is annotated #[marker] and prevents item overrides.
2914 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2915 -> Option<ImplOverlapKind>
2917 // If either trait impl references an error, they're allowed to overlap,
2918 // as one of them essentially doesn't exist.
2919 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error()) ||
2920 self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error()) {
2921 return Some(ImplOverlapKind::Permitted);
2924 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2925 (ImplPolarity::Reservation, _) |
2926 (_, ImplPolarity::Reservation) => {
2927 // `#[rustc_reservation_impl]` impls don't overlap with anything
2928 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2930 return Some(ImplOverlapKind::Permitted);
2932 (ImplPolarity::Positive, ImplPolarity::Negative) |
2933 (ImplPolarity::Negative, ImplPolarity::Positive) => {
2934 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2935 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2939 (ImplPolarity::Positive, ImplPolarity::Positive) |
2940 (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2943 let is_marker_overlap = if self.features().overlapping_marker_traits {
2944 let trait1_is_empty = self.impl_trait_ref(def_id1)
2945 .map_or(false, |trait_ref| {
2946 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2948 let trait2_is_empty = self.impl_trait_ref(def_id2)
2949 .map_or(false, |trait_ref| {
2950 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2952 trait1_is_empty && trait2_is_empty
2954 let is_marker_impl = |def_id: DefId| -> bool {
2955 let trait_ref = self.impl_trait_ref(def_id);
2956 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2958 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2962 if is_marker_overlap {
2963 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2965 Some(ImplOverlapKind::Permitted)
2967 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2968 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2969 if self_ty1 == self_ty2 {
2970 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2972 return Some(ImplOverlapKind::Issue33140);
2974 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2975 def_id1, def_id2, self_ty1, self_ty2);
2980 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2986 /// Returns `ty::VariantDef` if `res` refers to a struct,
2987 /// or variant or their constructors, panics otherwise.
2988 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2990 Res::Def(DefKind::Variant, did) => {
2991 let enum_did = self.parent(did).unwrap();
2992 self.adt_def(enum_did).variant_with_id(did)
2994 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
2995 self.adt_def(did).non_enum_variant()
2997 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2998 let variant_did = self.parent(variant_ctor_did).unwrap();
2999 let enum_did = self.parent(variant_did).unwrap();
3000 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
3002 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
3003 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
3004 self.adt_def(struct_did).non_enum_variant()
3006 _ => bug!("expect_variant_res used with unexpected res {:?}", res)
3010 pub fn item_name(self, id: DefId) -> Symbol {
3011 if id.index == CRATE_DEF_INDEX {
3012 self.original_crate_name(id.krate)
3014 let def_key = self.def_key(id);
3015 match def_key.disambiguated_data.data {
3016 // The name of a constructor is that of its parent.
3017 hir_map::DefPathData::Ctor =>
3018 self.item_name(DefId {
3020 index: def_key.parent.unwrap()
3022 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
3023 bug!("item_name: no name for {:?}", self.def_path(id));
3029 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
3030 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
3032 ty::InstanceDef::Item(did) => {
3033 self.optimized_mir(did)
3035 ty::InstanceDef::VtableShim(..) |
3036 ty::InstanceDef::ReifyShim(..) |
3037 ty::InstanceDef::Intrinsic(..) |
3038 ty::InstanceDef::FnPtrShim(..) |
3039 ty::InstanceDef::Virtual(..) |
3040 ty::InstanceDef::ClosureOnceShim { .. } |
3041 ty::InstanceDef::DropGlue(..) |
3042 ty::InstanceDef::CloneShim(..) => {
3043 self.mir_shims(instance)
3048 /// Gets the attributes of a definition.
3049 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
3050 if let Some(id) = self.hir().as_local_hir_id(did) {
3051 Attributes::Borrowed(self.hir().attrs(id))
3053 Attributes::Owned(self.item_attrs(did))
3057 /// Determines whether an item is annotated with an attribute.
3058 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
3059 attr::contains_name(&self.get_attrs(did), attr)
3062 /// Returns `true` if this is an `auto trait`.
3063 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3064 self.trait_def(trait_def_id).has_auto_impl
3067 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3068 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3071 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3072 /// If it implements no trait, returns `None`.
3073 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3074 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3077 /// If the given defid describes a method belonging to an impl, returns the
3078 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3079 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3080 let item = if def_id.krate != LOCAL_CRATE {
3081 if let Some(DefKind::Method) = self.def_kind(def_id) {
3082 Some(self.associated_item(def_id))
3087 self.opt_associated_item(def_id)
3090 item.and_then(|trait_item|
3091 match trait_item.container {
3092 TraitContainer(_) => None,
3093 ImplContainer(def_id) => Some(def_id),
3098 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3099 /// with the name of the crate containing the impl.
3100 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3101 if impl_did.is_local() {
3102 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3103 Ok(self.hir().span(hir_id))
3105 Err(self.crate_name(impl_did.krate))
3109 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3110 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3111 /// definition's parent/scope to perform comparison.
3112 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3113 // We could use `Ident::eq` here, but we deliberately don't. The name
3114 // comparison fails frequently, and we want to avoid the expensive
3115 // `modern()` calls required for the span comparison whenever possible.
3116 use_name.name == def_name.name &&
3117 use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
3118 self.expansion_that_defined(def_parent_def_id))
3121 fn expansion_that_defined(self, scope: DefId) -> ExpnId {
3123 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3124 _ => ExpnId::root(),
3128 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
3129 ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
3133 pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
3135 let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
3136 Some(actual_expansion) =>
3137 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3138 None => self.hir().get_module_parent(block),
3144 pub struct AssocItemsIterator<'tcx> {
3146 def_ids: &'tcx [DefId],
3150 impl Iterator for AssocItemsIterator<'_> {
3151 type Item = AssocItem;
3153 fn next(&mut self) -> Option<AssocItem> {
3154 let def_id = self.def_ids.get(self.next_index)?;
3155 self.next_index += 1;
3156 Some(self.tcx.associated_item(*def_id))
3160 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
3161 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3162 let parent_id = tcx.hir().get_parent_item(id);
3163 let parent_def_id = tcx.hir().local_def_id(parent_id);
3164 let parent_item = tcx.hir().expect_item(parent_id);
3165 match parent_item.kind {
3166 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3167 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3168 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3170 debug_assert_eq!(assoc_item.def_id, def_id);
3175 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3176 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3177 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3180 debug_assert_eq!(assoc_item.def_id, def_id);
3188 span_bug!(parent_item.span,
3189 "unexpected parent of trait or impl item or item not found: {:?}",
3193 #[derive(Clone, HashStable)]
3194 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3196 /// Calculates the `Sized` constraint.
3198 /// In fact, there are only a few options for the types in the constraint:
3199 /// - an obviously-unsized type
3200 /// - a type parameter or projection whose Sizedness can't be known
3201 /// - a tuple of type parameters or projections, if there are multiple
3203 /// - a Error, if a type contained itself. The representability
3204 /// check should catch this case.
3205 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
3206 let def = tcx.adt_def(def_id);
3208 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3211 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3214 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3216 AdtSizedConstraint(result)
3219 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
3220 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3221 let item = tcx.hir().expect_item(id);
3223 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3224 tcx.arena.alloc_from_iter(
3225 trait_item_refs.iter()
3226 .map(|trait_item_ref| trait_item_ref.id)
3227 .map(|id| tcx.hir().local_def_id(id.hir_id))
3230 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3231 tcx.arena.alloc_from_iter(
3232 impl_item_refs.iter()
3233 .map(|impl_item_ref| impl_item_ref.id)
3234 .map(|id| tcx.hir().local_def_id(id.hir_id))
3237 hir::ItemKind::TraitAlias(..) => &[],
3238 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3242 fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
3243 tcx.hir().span_if_local(def_id).unwrap()
3246 /// If the given `DefId` describes an item belonging to a trait,
3247 /// returns the `DefId` of the trait that the trait item belongs to;
3248 /// otherwise, returns `None`.
3249 fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3250 tcx.opt_associated_item(def_id)
3251 .and_then(|associated_item| {
3252 match associated_item.container {
3253 TraitContainer(def_id) => Some(def_id),
3254 ImplContainer(_) => None
3259 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3260 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3261 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3262 if let Node::Item(item) = tcx.hir().get(hir_id) {
3263 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
3264 return opaque_ty.impl_trait_fn;
3271 /// See `ParamEnv` struct definition for details.
3272 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
3273 // The param_env of an impl Trait type is its defining function's param_env
3274 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3275 return param_env(tcx, parent);
3277 // Compute the bounds on Self and the type parameters.
3279 let InstantiatedPredicates { predicates } =
3280 tcx.predicates_of(def_id).instantiate_identity(tcx);
3282 // Finally, we have to normalize the bounds in the environment, in
3283 // case they contain any associated type projections. This process
3284 // can yield errors if the put in illegal associated types, like
3285 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3286 // report these errors right here; this doesn't actually feel
3287 // right to me, because constructing the environment feels like a
3288 // kind of a "idempotent" action, but I'm not sure where would be
3289 // a better place. In practice, we construct environments for
3290 // every fn once during type checking, and we'll abort if there
3291 // are any errors at that point, so after type checking you can be
3292 // sure that this will succeed without errors anyway.
3294 let unnormalized_env = ty::ParamEnv::new(
3295 tcx.intern_predicates(&predicates),
3296 traits::Reveal::UserFacing,
3297 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3300 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3301 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
3303 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3304 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3307 fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
3308 assert_eq!(crate_num, LOCAL_CRATE);
3309 tcx.sess.local_crate_disambiguator()
3312 fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
3313 assert_eq!(crate_num, LOCAL_CRATE);
3314 tcx.crate_name.clone()
3317 fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
3318 assert_eq!(crate_num, LOCAL_CRATE);
3319 tcx.hir().crate_hash
3322 fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
3323 match instance_def {
3324 InstanceDef::Item(..) |
3325 InstanceDef::DropGlue(..) => {
3326 let mir = tcx.instance_mir(instance_def);
3327 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3329 // Estimate the size of other compiler-generated shims to be 1.
3334 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3336 /// See [`ImplOverlapKind::Issue33140`] for more details.
3337 fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
3338 debug!("issue33140_self_ty({:?})", def_id);
3340 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3341 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3344 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3346 let is_marker_like =
3347 tcx.impl_polarity(def_id) == ty::ImplPolarity::Positive &&
3348 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3350 // Check whether these impls would be ok for a marker trait.
3351 if !is_marker_like {
3352 debug!("issue33140_self_ty - not marker-like!");
3356 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3357 if trait_ref.substs.len() != 1 {
3358 debug!("issue33140_self_ty - impl has substs!");
3362 let predicates = tcx.predicates_of(def_id);
3363 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3364 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3368 let self_ty = trait_ref.self_ty();
3369 let self_ty_matches = match self_ty.kind {
3370 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3374 if self_ty_matches {
3375 debug!("issue33140_self_ty - MATCHES!");
3378 debug!("issue33140_self_ty - non-matching self type");
3383 /// Check if a function is async.
3384 fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
3385 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap_or_else(|| {
3386 bug!("asyncness: expected local `DefId`, got `{:?}`", def_id)
3389 let node = tcx.hir().get(hir_id);
3391 let fn_like = hir::map::blocks::FnLikeNode::from_node(node).unwrap_or_else(|| {
3392 bug!("asyncness: expected fn-like node but got `{:?}`", def_id);
3398 pub enum NonStructuralMatchTy<'tcx> {
3403 /// This method traverses the structure of `ty`, trying to find an
3404 /// instance of an ADT (i.e. struct or enum) that was declared without
3405 /// the `#[structural_match]` attribute, or a generic type parameter
3406 /// (which cannot be determined to be `structural_match`).
3408 /// The "structure of a type" includes all components that would be
3409 /// considered when doing a pattern match on a constant of that
3412 /// * This means this method descends into fields of structs/enums,
3413 /// and also descends into the inner type `T` of `&T` and `&mut T`
3415 /// * The traversal doesn't dereference unsafe pointers (`*const T`,
3416 /// `*mut T`), and it does not visit the type arguments of an
3417 /// instantiated generic like `PhantomData<T>`.
3419 /// The reason we do this search is Rust currently require all ADTs
3420 /// reachable from a constant's type to be annotated with
3421 /// `#[structural_match]`, an attribute which essentially says that
3422 /// the implementation of `PartialEq::eq` behaves *equivalently* to a
3423 /// comparison against the unfolded structure.
3425 /// For more background on why Rust has this requirement, and issues
3426 /// that arose when the requirement was not enforced completely, see
3427 /// Rust RFC 1445, rust-lang/rust#61188, and rust-lang/rust#62307.
3428 pub fn search_for_structural_match_violation<'tcx>(
3431 ) -> Option<NonStructuralMatchTy<'tcx>> {
3432 let mut search = Search { tcx, found: None, seen: FxHashSet::default() };
3433 ty.visit_with(&mut search);
3434 return search.found;
3436 struct Search<'tcx> {
3439 // Records the first ADT or type parameter we find without `#[structural_match`.
3440 found: Option<NonStructuralMatchTy<'tcx>>,
3442 // Tracks ADTs previously encountered during search, so that
3443 // we will not recurse on them again.
3444 seen: FxHashSet<hir::def_id::DefId>,
3447 impl<'tcx> TypeVisitor<'tcx> for Search<'tcx> {
3448 fn visit_ty(&mut self, ty: Ty<'tcx>) -> bool {
3449 debug!("Search visiting ty: {:?}", ty);
3451 let (adt_def, substs) = match ty.kind {
3452 ty::Adt(adt_def, substs) => (adt_def, substs),
3454 self.found = Some(NonStructuralMatchTy::Param);
3455 return true; // Stop visiting.
3458 // `#[structural_match]` ignores substructure of
3459 // `*const _`/`*mut _`, so skip super_visit_with
3461 // (But still tell caller to continue search.)
3464 ty::FnDef(..) | ty::FnPtr(..) => {
3465 // types of formals and return in `fn(_) -> _` are also irrelevant
3467 // (But still tell caller to continue search.)
3470 ty::Array(_, n) if n.try_eval_usize(self.tcx, ty::ParamEnv::reveal_all()) == Some(0)
3472 // rust-lang/rust#62336: ignore type of contents
3477 ty.super_visit_with(self);
3482 if !self.tcx.has_attr(adt_def.did, sym::structural_match) {
3483 self.found = Some(NonStructuralMatchTy::Adt(&adt_def));
3484 debug!("Search found adt_def: {:?}", adt_def);
3485 return true; // Stop visiting.
3488 if !self.seen.insert(adt_def.did) {
3489 debug!("Search already seen adt_def: {:?}", adt_def);
3490 // let caller continue its search
3494 // `#[structural_match]` does not care about the
3495 // instantiation of the generics in an ADT (it
3496 // instead looks directly at its fields outside
3497 // this match), so we skip super_visit_with.
3499 // (Must not recur on substs for `PhantomData<T>` cf
3500 // rust-lang/rust#55028 and rust-lang/rust#55837; but also
3501 // want to skip substs when only uses of generic are
3502 // behind unsafe pointers `*const T`/`*mut T`.)
3504 // even though we skip super_visit_with, we must recur on
3507 for field_ty in adt_def.all_fields().map(|field| field.ty(tcx, substs)) {
3508 if field_ty.visit_with(self) {
3509 // found an ADT without `#[structural_match]`; halt visiting!
3510 assert!(self.found.is_some());
3515 // Even though we do not want to recur on substs, we do
3516 // want our caller to continue its own search.
3522 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3523 context::provide(providers);
3524 erase_regions::provide(providers);
3525 layout::provide(providers);
3526 util::provide(providers);
3527 constness::provide(providers);
3528 crate::traits::query::dropck_outlives::provide(providers);
3529 *providers = ty::query::Providers {
3532 associated_item_def_ids,
3533 adt_sized_constraint,
3537 crate_disambiguator,
3538 original_crate_name,
3540 trait_impls_of: trait_def::trait_impls_of_provider,
3541 instance_def_size_estimate,
3547 /// A map for the local crate mapping each type to a vector of its
3548 /// inherent impls. This is not meant to be used outside of coherence;
3549 /// rather, you should request the vector for a specific type via
3550 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3551 /// (constructing this map requires touching the entire crate).
3552 #[derive(Clone, Debug, Default, HashStable)]
3553 pub struct CrateInherentImpls {
3554 pub inherent_impls: DefIdMap<Vec<DefId>>,
3557 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable)]
3558 pub struct SymbolName {
3559 // FIXME: we don't rely on interning or equality here - better have
3560 // this be a `&'tcx str`.
3564 impl_stable_hash_for!(struct self::SymbolName {
3569 pub fn new(name: &str) -> SymbolName {
3571 name: Symbol::intern(name)
3576 impl PartialOrd for SymbolName {
3577 fn partial_cmp(&self, other: &SymbolName) -> Option<Ordering> {
3578 self.name.as_str().partial_cmp(&other.name.as_str())
3582 /// Ordering must use the chars to ensure reproducible builds.
3583 impl Ord for SymbolName {
3584 fn cmp(&self, other: &SymbolName) -> Ordering {
3585 self.name.as_str().cmp(&other.name.as_str())
3589 impl fmt::Display for SymbolName {
3590 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3591 fmt::Display::fmt(&self.name, fmt)
3595 impl fmt::Debug for SymbolName {
3596 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3597 fmt::Display::fmt(&self.name, fmt)