1 // ignore-tidy-filelength
3 #![allow(usage_of_ty_tykind)]
5 pub use self::Variance::*;
6 pub use self::AssociatedItemContainer::*;
7 pub use self::BorrowKind::*;
8 pub use self::IntVarValue::*;
9 pub use self::fold::TypeFoldable;
11 use crate::hir::{map as hir_map, UpvarMap, GlobMap, TraitMap};
13 use crate::hir::def::{Res, DefKind, CtorOf, CtorKind, ExportMap};
14 use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
15 use rustc_data_structures::svh::Svh;
16 use rustc_macros::HashStable;
17 use crate::ich::Fingerprint;
18 use crate::ich::StableHashingContext;
19 use crate::infer::canonical::Canonical;
20 use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
21 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
23 use crate::mir::interpret::{GlobalId, ErrorHandled};
24 use crate::mir::GeneratorLayout;
25 use crate::session::CrateDisambiguator;
26 use crate::traits::{self, Reveal};
28 use crate::ty::layout::VariantIdx;
29 use crate::ty::subst::{Subst, InternalSubsts, SubstsRef};
30 use crate::ty::util::{IntTypeExt, Discr};
31 use crate::ty::walk::TypeWalker;
32 use crate::util::captures::Captures;
33 use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap};
34 use arena::SyncDroplessArena;
35 use crate::session::DataTypeKind;
37 use serialize::{self, Encodable, Encoder};
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::ext::hygiene::Mark;
50 use syntax::symbol::{keywords, sym, Symbol, LocalInternedString, InternedString};
54 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
55 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
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, GlobalArenas, AllArenas, tls, keep_local};
79 pub use self::context::{Lift, 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;
124 pub struct Resolutions {
125 pub upvars: UpvarMap,
126 pub trait_map: TraitMap,
127 pub maybe_unused_trait_imports: NodeSet,
128 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
129 pub export_map: ExportMap<NodeId>,
130 pub glob_map: GlobMap,
131 /// Extern prelude entries. The value is `true` if the entry was introduced
132 /// via `extern crate` item and not `--extern` option or compiler built-in.
133 pub extern_prelude: FxHashMap<Name, bool>,
136 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
137 pub enum AssociatedItemContainer {
138 TraitContainer(DefId),
139 ImplContainer(DefId),
142 impl AssociatedItemContainer {
143 /// Asserts that this is the `DefId` of an associated item declared
144 /// in a trait, and returns the trait `DefId`.
145 pub fn assert_trait(&self) -> DefId {
147 TraitContainer(id) => id,
148 _ => bug!("associated item has wrong container type: {:?}", self)
152 pub fn id(&self) -> DefId {
154 TraitContainer(id) => id,
155 ImplContainer(id) => id,
160 /// The "header" of an impl is everything outside the body: a Self type, a trait
161 /// ref (in the case of a trait impl), and a set of predicates (from the
162 /// bounds / where-clauses).
163 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
164 pub struct ImplHeader<'tcx> {
165 pub impl_def_id: DefId,
166 pub self_ty: Ty<'tcx>,
167 pub trait_ref: Option<TraitRef<'tcx>>,
168 pub predicates: Vec<Predicate<'tcx>>,
171 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
172 pub struct AssociatedItem {
174 #[stable_hasher(project(name))]
176 pub kind: AssociatedKind,
178 pub defaultness: hir::Defaultness,
179 pub container: AssociatedItemContainer,
181 /// Whether this is a method with an explicit self
182 /// as its first argument, allowing method calls.
183 pub method_has_self_argument: bool,
186 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable, HashStable)]
187 pub enum AssociatedKind {
194 impl AssociatedItem {
195 pub fn def_kind(&self) -> DefKind {
197 AssociatedKind::Const => DefKind::AssociatedConst,
198 AssociatedKind::Method => DefKind::Method,
199 AssociatedKind::Type => DefKind::AssociatedTy,
200 AssociatedKind::Existential => DefKind::AssociatedExistential,
204 /// Tests whether the associated item admits a non-trivial implementation
206 pub fn relevant_for_never<'tcx>(&self) -> bool {
208 AssociatedKind::Existential |
209 AssociatedKind::Const |
210 AssociatedKind::Type => true,
211 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
212 AssociatedKind::Method => !self.method_has_self_argument,
216 pub fn signature<'a, 'tcx>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String {
218 ty::AssociatedKind::Method => {
219 // We skip the binder here because the binder would deanonymize all
220 // late-bound regions, and we don't want method signatures to show up
221 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
222 // regions just fine, showing `fn(&MyType)`.
223 tcx.fn_sig(self.def_id).skip_binder().to_string()
225 ty::AssociatedKind::Type => format!("type {};", self.ident),
226 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
227 ty::AssociatedKind::Const => {
228 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
234 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
235 pub enum Visibility {
236 /// Visible everywhere (including in other crates).
238 /// Visible only in the given crate-local module.
240 /// Not visible anywhere in the local crate. This is the visibility of private external items.
244 pub trait DefIdTree: Copy {
245 fn parent(self, id: DefId) -> Option<DefId>;
247 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
248 if descendant.krate != ancestor.krate {
252 while descendant != ancestor {
253 match self.parent(descendant) {
254 Some(parent) => descendant = parent,
255 None => return false,
262 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
263 fn parent(self, id: DefId) -> Option<DefId> {
264 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
269 pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_, '_, '_>) -> Self {
270 match visibility.node {
271 hir::VisibilityKind::Public => Visibility::Public,
272 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
273 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
274 // If there is no resolution, `resolve` will have already reported an error, so
275 // assume that the visibility is public to avoid reporting more privacy errors.
276 Res::Err => Visibility::Public,
277 def => Visibility::Restricted(def.def_id()),
279 hir::VisibilityKind::Inherited => {
280 Visibility::Restricted(tcx.hir().get_module_parent_by_hir_id(id))
285 /// Returns `true` if an item with this visibility is accessible from the given block.
286 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
287 let restriction = match self {
288 // Public items are visible everywhere.
289 Visibility::Public => return true,
290 // Private items from other crates are visible nowhere.
291 Visibility::Invisible => return false,
292 // Restricted items are visible in an arbitrary local module.
293 Visibility::Restricted(other) if other.krate != module.krate => return false,
294 Visibility::Restricted(module) => module,
297 tree.is_descendant_of(module, restriction)
300 /// Returns `true` if this visibility is at least as accessible as the given visibility
301 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
302 let vis_restriction = match vis {
303 Visibility::Public => return self == Visibility::Public,
304 Visibility::Invisible => return true,
305 Visibility::Restricted(module) => module,
308 self.is_accessible_from(vis_restriction, tree)
311 // Returns `true` if this item is visible anywhere in the local crate.
312 pub fn is_visible_locally(self) -> bool {
314 Visibility::Public => true,
315 Visibility::Restricted(def_id) => def_id.is_local(),
316 Visibility::Invisible => false,
321 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash, HashStable)]
323 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
324 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
325 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
326 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
329 /// The crate variances map is computed during typeck and contains the
330 /// variance of every item in the local crate. You should not use it
331 /// directly, because to do so will make your pass dependent on the
332 /// HIR of every item in the local crate. Instead, use
333 /// `tcx.variances_of()` to get the variance for a *particular*
335 #[derive(HashStable)]
336 pub struct CrateVariancesMap<'tcx> {
337 /// For each item with generics, maps to a vector of the variance
338 /// of its generics. If an item has no generics, it will have no
340 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
344 /// `a.xform(b)` combines the variance of a context with the
345 /// variance of a type with the following meaning. If we are in a
346 /// context with variance `a`, and we encounter a type argument in
347 /// a position with variance `b`, then `a.xform(b)` is the new
348 /// variance with which the argument appears.
354 /// Here, the "ambient" variance starts as covariant. `*mut T` is
355 /// invariant with respect to `T`, so the variance in which the
356 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
357 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
358 /// respect to its type argument `T`, and hence the variance of
359 /// the `i32` here is `Invariant.xform(Covariant)`, which results
360 /// (again) in `Invariant`.
364 /// fn(*const Vec<i32>, *mut Vec<i32)
366 /// The ambient variance is covariant. A `fn` type is
367 /// contravariant with respect to its parameters, so the variance
368 /// within which both pointer types appear is
369 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
370 /// T` is covariant with respect to `T`, so the variance within
371 /// which the first `Vec<i32>` appears is
372 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
373 /// is true for its `i32` argument. In the `*mut T` case, the
374 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
375 /// and hence the outermost type is `Invariant` with respect to
376 /// `Vec<i32>` (and its `i32` argument).
378 /// Source: Figure 1 of "Taming the Wildcards:
379 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
380 pub fn xform(self, v: ty::Variance) -> ty::Variance {
382 // Figure 1, column 1.
383 (ty::Covariant, ty::Covariant) => ty::Covariant,
384 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
385 (ty::Covariant, ty::Invariant) => ty::Invariant,
386 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
388 // Figure 1, column 2.
389 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
390 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
391 (ty::Contravariant, ty::Invariant) => ty::Invariant,
392 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
394 // Figure 1, column 3.
395 (ty::Invariant, _) => ty::Invariant,
397 // Figure 1, column 4.
398 (ty::Bivariant, _) => ty::Bivariant,
403 // Contains information needed to resolve types and (in the future) look up
404 // the types of AST nodes.
405 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
406 pub struct CReaderCacheKey {
411 // Flags that we track on types. These flags are propagated upwards
412 // through the type during type construction, so that we can quickly
413 // check whether the type has various kinds of types in it without
414 // recursing over the type itself.
416 pub struct TypeFlags: u32 {
417 const HAS_PARAMS = 1 << 0;
418 const HAS_SELF = 1 << 1;
419 const HAS_TY_INFER = 1 << 2;
420 const HAS_RE_INFER = 1 << 3;
421 const HAS_RE_PLACEHOLDER = 1 << 4;
423 /// Does this have any `ReEarlyBound` regions? Used to
424 /// determine whether substitition is required, since those
425 /// represent regions that are bound in a `ty::Generics` and
426 /// hence may be substituted.
427 const HAS_RE_EARLY_BOUND = 1 << 5;
429 /// Does this have any region that "appears free" in the type?
430 /// Basically anything but `ReLateBound` and `ReErased`.
431 const HAS_FREE_REGIONS = 1 << 6;
433 /// Is an error type reachable?
434 const HAS_TY_ERR = 1 << 7;
435 const HAS_PROJECTION = 1 << 8;
437 // FIXME: Rename this to the actual property since it's used for generators too
438 const HAS_TY_CLOSURE = 1 << 9;
440 /// `true` if there are "names" of types and regions and so forth
441 /// that are local to a particular fn
442 const HAS_FREE_LOCAL_NAMES = 1 << 10;
444 /// Present if the type belongs in a local type context.
445 /// Only set for Infer other than Fresh.
446 const KEEP_IN_LOCAL_TCX = 1 << 11;
448 // Is there a projection that does not involve a bound region?
449 // Currently we can't normalize projections w/ bound regions.
450 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
452 /// Does this have any `ReLateBound` regions? Used to check
453 /// if a global bound is safe to evaluate.
454 const HAS_RE_LATE_BOUND = 1 << 13;
456 const HAS_TY_PLACEHOLDER = 1 << 14;
458 const HAS_CT_INFER = 1 << 15;
459 const HAS_CT_PLACEHOLDER = 1 << 16;
461 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
462 TypeFlags::HAS_SELF.bits |
463 TypeFlags::HAS_RE_EARLY_BOUND.bits;
465 /// Flags representing the nominal content of a type,
466 /// computed by FlagsComputation. If you add a new nominal
467 /// flag, it should be added here too.
468 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
469 TypeFlags::HAS_SELF.bits |
470 TypeFlags::HAS_TY_INFER.bits |
471 TypeFlags::HAS_RE_INFER.bits |
472 TypeFlags::HAS_CT_INFER.bits |
473 TypeFlags::HAS_RE_PLACEHOLDER.bits |
474 TypeFlags::HAS_RE_EARLY_BOUND.bits |
475 TypeFlags::HAS_FREE_REGIONS.bits |
476 TypeFlags::HAS_TY_ERR.bits |
477 TypeFlags::HAS_PROJECTION.bits |
478 TypeFlags::HAS_TY_CLOSURE.bits |
479 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
480 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
481 TypeFlags::HAS_RE_LATE_BOUND.bits |
482 TypeFlags::HAS_TY_PLACEHOLDER.bits |
483 TypeFlags::HAS_CT_PLACEHOLDER.bits;
487 pub struct TyS<'tcx> {
488 pub sty: TyKind<'tcx>,
489 pub flags: TypeFlags,
491 /// This is a kind of confusing thing: it stores the smallest
494 /// (a) the binder itself captures nothing but
495 /// (b) all the late-bound things within the type are captured
496 /// by some sub-binder.
498 /// So, for a type without any late-bound things, like `u32`, this
499 /// will be *innermost*, because that is the innermost binder that
500 /// captures nothing. But for a type `&'D u32`, where `'D` is a
501 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
502 /// -- the binder itself does not capture `D`, but `D` is captured
503 /// by an inner binder.
505 /// We call this concept an "exclusive" binder `D` because all
506 /// De Bruijn indices within the type are contained within `0..D`
508 outer_exclusive_binder: ty::DebruijnIndex,
511 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
512 #[cfg(target_arch = "x86_64")]
513 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
515 impl<'tcx> Ord for TyS<'tcx> {
516 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
517 self.sty.cmp(&other.sty)
521 impl<'tcx> PartialOrd for TyS<'tcx> {
522 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
523 Some(self.sty.cmp(&other.sty))
527 impl<'tcx> PartialEq for TyS<'tcx> {
529 fn eq(&self, other: &TyS<'tcx>) -> bool {
533 impl<'tcx> Eq for TyS<'tcx> {}
535 impl<'tcx> Hash for TyS<'tcx> {
536 fn hash<H: Hasher>(&self, s: &mut H) {
537 (self as *const TyS<'_>).hash(s)
541 impl<'tcx> TyS<'tcx> {
542 pub fn is_primitive_ty(&self) -> bool {
549 TyKind::Infer(InferTy::IntVar(_)) |
550 TyKind::Infer(InferTy::FloatVar(_)) |
551 TyKind::Infer(InferTy::FreshIntTy(_)) |
552 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
553 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
558 pub fn is_suggestable(&self) -> bool {
563 TyKind::Dynamic(..) |
564 TyKind::Closure(..) |
566 TyKind::Projection(..) => false,
572 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
573 fn hash_stable<W: StableHasherResult>(&self,
574 hcx: &mut StableHashingContext<'a>,
575 hasher: &mut StableHasher<W>) {
579 // The other fields just provide fast access to information that is
580 // also contained in `sty`, so no need to hash them.
583 outer_exclusive_binder: _,
586 sty.hash_stable(hcx, hasher);
590 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
592 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
593 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
595 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
598 /// A dummy type used to force List to by unsized without requiring fat pointers
599 type OpaqueListContents;
602 /// A wrapper for slices with the additional invariant
603 /// that the slice is interned and no other slice with
604 /// the same contents can exist in the same context.
605 /// This means we can use pointer for both
606 /// equality comparisons and hashing.
607 /// Note: `Slice` was already taken by the `Ty`.
612 opaque: OpaqueListContents,
615 unsafe impl<T: Sync> Sync for List<T> {}
617 impl<T: Copy> List<T> {
619 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
620 assert!(!mem::needs_drop::<T>());
621 assert!(mem::size_of::<T>() != 0);
622 assert!(slice.len() != 0);
624 // Align up the size of the len (usize) field
625 let align = mem::align_of::<T>();
626 let align_mask = align - 1;
627 let offset = mem::size_of::<usize>();
628 let offset = (offset + align_mask) & !align_mask;
630 let size = offset + slice.len() * mem::size_of::<T>();
632 let mem = arena.alloc_raw(
634 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
636 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
638 result.len = slice.len();
640 // Write the elements
641 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
642 arena_slice.copy_from_slice(slice);
649 impl<T: fmt::Debug> fmt::Debug for List<T> {
650 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
655 impl<T: Encodable> Encodable for List<T> {
657 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
662 impl<T> Ord for List<T> where T: Ord {
663 fn cmp(&self, other: &List<T>) -> Ordering {
664 if self == other { Ordering::Equal } else {
665 <[T] as Ord>::cmp(&**self, &**other)
670 impl<T> PartialOrd for List<T> where T: PartialOrd {
671 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
672 if self == other { Some(Ordering::Equal) } else {
673 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
678 impl<T: PartialEq> PartialEq for List<T> {
680 fn eq(&self, other: &List<T>) -> bool {
684 impl<T: Eq> Eq for List<T> {}
686 impl<T> Hash for List<T> {
688 fn hash<H: Hasher>(&self, s: &mut H) {
689 (self as *const List<T>).hash(s)
693 impl<T> Deref for List<T> {
696 fn deref(&self) -> &[T] {
698 slice::from_raw_parts(self.data.as_ptr(), self.len)
703 impl<'a, T> IntoIterator for &'a List<T> {
705 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
707 fn into_iter(self) -> Self::IntoIter {
712 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
716 pub fn empty<'a>() -> &'a List<T> {
717 #[repr(align(64), C)]
718 struct EmptySlice([u8; 64]);
719 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
720 assert!(mem::align_of::<T>() <= 64);
722 &*(&EMPTY_SLICE as *const _ as *const List<T>)
727 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
728 pub struct UpvarPath {
729 pub hir_id: hir::HirId,
732 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
733 /// the original var ID (that is, the root variable that is referenced
734 /// by the upvar) and the ID of the closure expression.
735 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
737 pub var_path: UpvarPath,
738 pub closure_expr_id: LocalDefId,
741 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
742 pub enum BorrowKind {
743 /// Data must be immutable and is aliasable.
746 /// Data must be immutable but not aliasable. This kind of borrow
747 /// cannot currently be expressed by the user and is used only in
748 /// implicit closure bindings. It is needed when the closure
749 /// is borrowing or mutating a mutable referent, e.g.:
751 /// let x: &mut isize = ...;
752 /// let y = || *x += 5;
754 /// If we were to try to translate this closure into a more explicit
755 /// form, we'd encounter an error with the code as written:
757 /// struct Env { x: & &mut isize }
758 /// let x: &mut isize = ...;
759 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
760 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
762 /// This is then illegal because you cannot mutate a `&mut` found
763 /// in an aliasable location. To solve, you'd have to translate with
764 /// an `&mut` borrow:
766 /// struct Env { x: & &mut isize }
767 /// let x: &mut isize = ...;
768 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
769 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
771 /// Now the assignment to `**env.x` is legal, but creating a
772 /// mutable pointer to `x` is not because `x` is not mutable. We
773 /// could fix this by declaring `x` as `let mut x`. This is ok in
774 /// user code, if awkward, but extra weird for closures, since the
775 /// borrow is hidden.
777 /// So we introduce a "unique imm" borrow -- the referent is
778 /// immutable, but not aliasable. This solves the problem. For
779 /// simplicity, we don't give users the way to express this
780 /// borrow, it's just used when translating closures.
783 /// Data is mutable and not aliasable.
787 /// Information describing the capture of an upvar. This is computed
788 /// during `typeck`, specifically by `regionck`.
789 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
790 pub enum UpvarCapture<'tcx> {
791 /// Upvar is captured by value. This is always true when the
792 /// closure is labeled `move`, but can also be true in other cases
793 /// depending on inference.
796 /// Upvar is captured by reference.
797 ByRef(UpvarBorrow<'tcx>),
800 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
801 pub struct UpvarBorrow<'tcx> {
802 /// The kind of borrow: by-ref upvars have access to shared
803 /// immutable borrows, which are not part of the normal language
805 pub kind: BorrowKind,
807 /// Region of the resulting reference.
808 pub region: ty::Region<'tcx>,
811 pub type UpvarListMap = FxHashMap<DefId, Vec<UpvarId>>;
812 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
814 #[derive(Copy, Clone)]
815 pub struct ClosureUpvar<'tcx> {
821 #[derive(Clone, Copy, PartialEq, Eq)]
822 pub enum IntVarValue {
824 UintType(ast::UintTy),
827 #[derive(Clone, Copy, PartialEq, Eq)]
828 pub struct FloatVarValue(pub ast::FloatTy);
830 impl ty::EarlyBoundRegion {
831 pub fn to_bound_region(&self) -> ty::BoundRegion {
832 ty::BoundRegion::BrNamed(self.def_id, self.name)
835 /// Does this early bound region have a name? Early bound regions normally
836 /// always have names except when using anonymous lifetimes (`'_`).
837 pub fn has_name(&self) -> bool {
838 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
842 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
843 pub enum GenericParamDefKind {
847 object_lifetime_default: ObjectLifetimeDefault,
848 synthetic: Option<hir::SyntheticTyParamKind>,
853 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
854 pub struct GenericParamDef {
855 pub name: InternedString,
859 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
860 /// on generic parameter `'a`/`T`, asserts data behind the parameter
861 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
862 pub pure_wrt_drop: bool,
864 pub kind: GenericParamDefKind,
867 impl GenericParamDef {
868 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
869 if let GenericParamDefKind::Lifetime = self.kind {
870 ty::EarlyBoundRegion {
876 bug!("cannot convert a non-lifetime parameter def to an early bound region")
880 pub fn to_bound_region(&self) -> ty::BoundRegion {
881 if let GenericParamDefKind::Lifetime = self.kind {
882 self.to_early_bound_region_data().to_bound_region()
884 bug!("cannot convert a non-lifetime parameter def to an early bound region")
890 pub struct GenericParamCount {
891 pub lifetimes: usize,
896 /// Information about the formal type/lifetime parameters associated
897 /// with an item or method. Analogous to `hir::Generics`.
899 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
900 /// `Self` (optionally), `Lifetime` params..., `Type` params...
901 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
902 pub struct Generics {
903 pub parent: Option<DefId>,
904 pub parent_count: usize,
905 pub params: Vec<GenericParamDef>,
907 /// Reverse map to the `index` field of each `GenericParamDef`
908 #[stable_hasher(ignore)]
909 pub param_def_id_to_index: FxHashMap<DefId, u32>,
912 pub has_late_bound_regions: Option<Span>,
915 impl<'a, 'gcx, 'tcx> Generics {
916 pub fn count(&self) -> usize {
917 self.parent_count + self.params.len()
920 pub fn own_counts(&self) -> GenericParamCount {
921 // We could cache this as a property of `GenericParamCount`, but
922 // the aim is to refactor this away entirely eventually and the
923 // presence of this method will be a constant reminder.
924 let mut own_counts: GenericParamCount = Default::default();
926 for param in &self.params {
928 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
929 GenericParamDefKind::Type { .. } => own_counts.types += 1,
930 GenericParamDefKind::Const => own_counts.consts += 1,
937 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
938 if self.own_requires_monomorphization() {
942 if let Some(parent_def_id) = self.parent {
943 let parent = tcx.generics_of(parent_def_id);
944 parent.requires_monomorphization(tcx)
950 pub fn own_requires_monomorphization(&self) -> bool {
951 for param in &self.params {
953 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
954 GenericParamDefKind::Lifetime => {}
960 pub fn region_param(&'tcx self,
961 param: &EarlyBoundRegion,
962 tcx: TyCtxt<'a, 'gcx, 'tcx>)
963 -> &'tcx GenericParamDef
965 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
966 let param = &self.params[index as usize];
968 GenericParamDefKind::Lifetime => param,
969 _ => bug!("expected lifetime parameter, but found another generic parameter")
972 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
973 .region_param(param, tcx)
977 /// Returns the `GenericParamDef` associated with this `ParamTy`.
978 pub fn type_param(&'tcx self,
980 tcx: TyCtxt<'a, 'gcx, 'tcx>)
981 -> &'tcx GenericParamDef {
982 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
983 let param = &self.params[index as usize];
985 GenericParamDefKind::Type { .. } => param,
986 _ => bug!("expected type parameter, but found another generic parameter")
989 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
990 .type_param(param, tcx)
994 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
995 pub fn const_param(&'tcx self,
997 tcx: TyCtxt<'a, 'gcx, 'tcx>)
998 -> &GenericParamDef {
999 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
1000 let param = &self.params[index as usize];
1002 GenericParamDefKind::Const => param,
1003 _ => bug!("expected const parameter, but found another generic parameter")
1006 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1007 .const_param(param, tcx)
1012 /// Bounds on generics.
1013 #[derive(Clone, Default, Debug, HashStable)]
1014 pub struct GenericPredicates<'tcx> {
1015 pub parent: Option<DefId>,
1016 pub predicates: Vec<(Predicate<'tcx>, Span)>,
1019 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
1020 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
1022 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
1023 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: SubstsRef<'tcx>)
1024 -> InstantiatedPredicates<'tcx> {
1025 let mut instantiated = InstantiatedPredicates::empty();
1026 self.instantiate_into(tcx, &mut instantiated, substs);
1030 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: SubstsRef<'tcx>)
1031 -> InstantiatedPredicates<'tcx> {
1032 InstantiatedPredicates {
1033 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1037 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1038 instantiated: &mut InstantiatedPredicates<'tcx>,
1039 substs: SubstsRef<'tcx>) {
1040 if let Some(def_id) = self.parent {
1041 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1043 instantiated.predicates.extend(
1044 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1048 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1049 -> InstantiatedPredicates<'tcx> {
1050 let mut instantiated = InstantiatedPredicates::empty();
1051 self.instantiate_identity_into(tcx, &mut instantiated);
1055 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1056 instantiated: &mut InstantiatedPredicates<'tcx>) {
1057 if let Some(def_id) = self.parent {
1058 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1060 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1063 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1064 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1065 -> InstantiatedPredicates<'tcx>
1067 assert_eq!(self.parent, None);
1068 InstantiatedPredicates {
1069 predicates: self.predicates.iter().map(|(pred, _)| {
1070 pred.subst_supertrait(tcx, poly_trait_ref)
1076 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1077 pub enum Predicate<'tcx> {
1078 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1079 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1080 /// would be the type parameters.
1081 Trait(PolyTraitPredicate<'tcx>),
1084 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1087 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1089 /// where `<T as TraitRef>::Name == X`, approximately.
1090 /// See the `ProjectionPredicate` struct for details.
1091 Projection(PolyProjectionPredicate<'tcx>),
1093 /// no syntax: `T` well-formed
1094 WellFormed(Ty<'tcx>),
1096 /// trait must be object-safe
1099 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1100 /// for some substitutions `...` and `T` being a closure type.
1101 /// Satisfied (or refuted) once we know the closure's kind.
1102 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1105 Subtype(PolySubtypePredicate<'tcx>),
1107 /// Constant initializer must evaluate successfully.
1108 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1111 /// The crate outlives map is computed during typeck and contains the
1112 /// outlives of every item in the local crate. You should not use it
1113 /// directly, because to do so will make your pass dependent on the
1114 /// HIR of every item in the local crate. Instead, use
1115 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1117 #[derive(HashStable)]
1118 pub struct CratePredicatesMap<'tcx> {
1119 /// For each struct with outlive bounds, maps to a vector of the
1120 /// predicate of its outlive bounds. If an item has no outlives
1121 /// bounds, it will have no entry.
1122 pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
1125 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1126 fn as_ref(&self) -> &Predicate<'tcx> {
1131 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1132 /// Performs a substitution suitable for going from a
1133 /// poly-trait-ref to supertraits that must hold if that
1134 /// poly-trait-ref holds. This is slightly different from a normal
1135 /// substitution in terms of what happens with bound regions. See
1136 /// lengthy comment below for details.
1137 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1138 trait_ref: &ty::PolyTraitRef<'tcx>)
1139 -> ty::Predicate<'tcx>
1141 // The interaction between HRTB and supertraits is not entirely
1142 // obvious. Let me walk you (and myself) through an example.
1144 // Let's start with an easy case. Consider two traits:
1146 // trait Foo<'a>: Bar<'a,'a> { }
1147 // trait Bar<'b,'c> { }
1149 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1150 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1151 // knew that `Foo<'x>` (for any 'x) then we also know that
1152 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1153 // normal substitution.
1155 // In terms of why this is sound, the idea is that whenever there
1156 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1157 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1158 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1161 // Another example to be careful of is this:
1163 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1164 // trait Bar1<'b,'c> { }
1166 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1167 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1168 // reason is similar to the previous example: any impl of
1169 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1170 // basically we would want to collapse the bound lifetimes from
1171 // the input (`trait_ref`) and the supertraits.
1173 // To achieve this in practice is fairly straightforward. Let's
1174 // consider the more complicated scenario:
1176 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1177 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1178 // where both `'x` and `'b` would have a DB index of 1.
1179 // The substitution from the input trait-ref is therefore going to be
1180 // `'a => 'x` (where `'x` has a DB index of 1).
1181 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1182 // early-bound parameter and `'b' is a late-bound parameter with a
1184 // - If we replace `'a` with `'x` from the input, it too will have
1185 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1186 // just as we wanted.
1188 // There is only one catch. If we just apply the substitution `'a
1189 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1190 // adjust the DB index because we substituting into a binder (it
1191 // tries to be so smart...) resulting in `for<'x> for<'b>
1192 // Bar1<'x,'b>` (we have no syntax for this, so use your
1193 // imagination). Basically the 'x will have DB index of 2 and 'b
1194 // will have DB index of 1. Not quite what we want. So we apply
1195 // the substitution to the *contents* of the trait reference,
1196 // rather than the trait reference itself (put another way, the
1197 // substitution code expects equal binding levels in the values
1198 // from the substitution and the value being substituted into, and
1199 // this trick achieves that).
1201 let substs = &trait_ref.skip_binder().substs;
1203 Predicate::Trait(ref binder) =>
1204 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1205 Predicate::Subtype(ref binder) =>
1206 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1207 Predicate::RegionOutlives(ref binder) =>
1208 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1209 Predicate::TypeOutlives(ref binder) =>
1210 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1211 Predicate::Projection(ref binder) =>
1212 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1213 Predicate::WellFormed(data) =>
1214 Predicate::WellFormed(data.subst(tcx, substs)),
1215 Predicate::ObjectSafe(trait_def_id) =>
1216 Predicate::ObjectSafe(trait_def_id),
1217 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1218 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1219 Predicate::ConstEvaluatable(def_id, const_substs) =>
1220 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1225 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1226 pub struct TraitPredicate<'tcx> {
1227 pub trait_ref: TraitRef<'tcx>
1230 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1232 impl<'tcx> TraitPredicate<'tcx> {
1233 pub fn def_id(&self) -> DefId {
1234 self.trait_ref.def_id
1237 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1238 self.trait_ref.input_types()
1241 pub fn self_ty(&self) -> Ty<'tcx> {
1242 self.trait_ref.self_ty()
1246 impl<'tcx> PolyTraitPredicate<'tcx> {
1247 pub fn def_id(&self) -> DefId {
1248 // ok to skip binder since trait def-id does not care about regions
1249 self.skip_binder().def_id()
1253 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1254 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1255 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1256 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1257 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1259 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1261 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1262 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1264 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1265 pub struct SubtypePredicate<'tcx> {
1266 pub a_is_expected: bool,
1270 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1272 /// This kind of predicate has no *direct* correspondent in the
1273 /// syntax, but it roughly corresponds to the syntactic forms:
1275 /// 1. `T: TraitRef<..., Item = Type>`
1276 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1278 /// In particular, form #1 is "desugared" to the combination of a
1279 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1280 /// predicates. Form #2 is a broader form in that it also permits
1281 /// equality between arbitrary types. Processing an instance of
1282 /// Form #2 eventually yields one of these `ProjectionPredicate`
1283 /// instances to normalize the LHS.
1284 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1285 pub struct ProjectionPredicate<'tcx> {
1286 pub projection_ty: ProjectionTy<'tcx>,
1290 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1292 impl<'tcx> PolyProjectionPredicate<'tcx> {
1293 /// Returns the `DefId` of the associated item being projected.
1294 pub fn item_def_id(&self) -> DefId {
1295 self.skip_binder().projection_ty.item_def_id
1299 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1300 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1301 // `self.0.trait_ref` is permitted to have escaping regions.
1302 // This is because here `self` has a `Binder` and so does our
1303 // return value, so we are preserving the number of binding
1305 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1308 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1309 self.map_bound(|predicate| predicate.ty)
1312 /// The `DefId` of the `TraitItem` for the associated type.
1314 /// Note that this is not the `DefId` of the `TraitRef` containing this
1315 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1316 pub fn projection_def_id(&self) -> DefId {
1317 // okay to skip binder since trait def-id does not care about regions
1318 self.skip_binder().projection_ty.item_def_id
1322 pub trait ToPolyTraitRef<'tcx> {
1323 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1326 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1327 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1328 ty::Binder::dummy(self.clone())
1332 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1333 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1334 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1338 pub trait ToPredicate<'tcx> {
1339 fn to_predicate(&self) -> Predicate<'tcx>;
1342 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1343 fn to_predicate(&self) -> Predicate<'tcx> {
1344 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1345 trait_ref: self.clone()
1350 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1351 fn to_predicate(&self) -> Predicate<'tcx> {
1352 ty::Predicate::Trait(self.to_poly_trait_predicate())
1356 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1357 fn to_predicate(&self) -> Predicate<'tcx> {
1358 Predicate::RegionOutlives(self.clone())
1362 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1363 fn to_predicate(&self) -> Predicate<'tcx> {
1364 Predicate::TypeOutlives(self.clone())
1368 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1369 fn to_predicate(&self) -> Predicate<'tcx> {
1370 Predicate::Projection(self.clone())
1374 // A custom iterator used by Predicate::walk_tys.
1375 enum WalkTysIter<'tcx, I, J, K>
1376 where I: Iterator<Item = Ty<'tcx>>,
1377 J: Iterator<Item = Ty<'tcx>>,
1378 K: Iterator<Item = Ty<'tcx>>
1382 Two(Ty<'tcx>, Ty<'tcx>),
1388 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1389 where I: Iterator<Item = Ty<'tcx>>,
1390 J: Iterator<Item = Ty<'tcx>>,
1391 K: Iterator<Item = Ty<'tcx>>
1393 type Item = Ty<'tcx>;
1395 fn next(&mut self) -> Option<Ty<'tcx>> {
1397 WalkTysIter::None => None,
1398 WalkTysIter::One(item) => {
1399 *self = WalkTysIter::None;
1402 WalkTysIter::Two(item1, item2) => {
1403 *self = WalkTysIter::One(item2);
1406 WalkTysIter::Types(ref mut iter) => {
1409 WalkTysIter::InputTypes(ref mut iter) => {
1412 WalkTysIter::ProjectionTypes(ref mut iter) => {
1419 impl<'tcx> Predicate<'tcx> {
1420 /// Iterates over the types in this predicate. Note that in all
1421 /// cases this is skipping over a binder, so late-bound regions
1422 /// with depth 0 are bound by the predicate.
1423 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1425 ty::Predicate::Trait(ref data) => {
1426 WalkTysIter::InputTypes(data.skip_binder().input_types())
1428 ty::Predicate::Subtype(binder) => {
1429 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1430 WalkTysIter::Two(a, b)
1432 ty::Predicate::TypeOutlives(binder) => {
1433 WalkTysIter::One(binder.skip_binder().0)
1435 ty::Predicate::RegionOutlives(..) => {
1438 ty::Predicate::Projection(ref data) => {
1439 let inner = data.skip_binder();
1440 WalkTysIter::ProjectionTypes(
1441 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1443 ty::Predicate::WellFormed(data) => {
1444 WalkTysIter::One(data)
1446 ty::Predicate::ObjectSafe(_trait_def_id) => {
1449 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1450 WalkTysIter::Types(closure_substs.substs.types())
1452 ty::Predicate::ConstEvaluatable(_, substs) => {
1453 WalkTysIter::Types(substs.types())
1458 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1460 Predicate::Trait(ref t) => {
1461 Some(t.to_poly_trait_ref())
1463 Predicate::Projection(..) |
1464 Predicate::Subtype(..) |
1465 Predicate::RegionOutlives(..) |
1466 Predicate::WellFormed(..) |
1467 Predicate::ObjectSafe(..) |
1468 Predicate::ClosureKind(..) |
1469 Predicate::TypeOutlives(..) |
1470 Predicate::ConstEvaluatable(..) => {
1476 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1478 Predicate::TypeOutlives(data) => {
1481 Predicate::Trait(..) |
1482 Predicate::Projection(..) |
1483 Predicate::Subtype(..) |
1484 Predicate::RegionOutlives(..) |
1485 Predicate::WellFormed(..) |
1486 Predicate::ObjectSafe(..) |
1487 Predicate::ClosureKind(..) |
1488 Predicate::ConstEvaluatable(..) => {
1495 /// Represents the bounds declared on a particular set of type
1496 /// parameters. Should eventually be generalized into a flag list of
1497 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1498 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1499 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1500 /// the `GenericPredicates` are expressed in terms of the bound type
1501 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1502 /// represented a set of bounds for some particular instantiation,
1503 /// meaning that the generic parameters have been substituted with
1508 /// struct Foo<T,U:Bar<T>> { ... }
1510 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1511 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1512 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1513 /// [usize:Bar<isize>]]`.
1514 #[derive(Clone, Debug)]
1515 pub struct InstantiatedPredicates<'tcx> {
1516 pub predicates: Vec<Predicate<'tcx>>,
1519 impl<'tcx> InstantiatedPredicates<'tcx> {
1520 pub fn empty() -> InstantiatedPredicates<'tcx> {
1521 InstantiatedPredicates { predicates: vec![] }
1524 pub fn is_empty(&self) -> bool {
1525 self.predicates.is_empty()
1530 /// "Universes" are used during type- and trait-checking in the
1531 /// presence of `for<..>` binders to control what sets of names are
1532 /// visible. Universes are arranged into a tree: the root universe
1533 /// contains names that are always visible. Each child then adds a new
1534 /// set of names that are visible, in addition to those of its parent.
1535 /// We say that the child universe "extends" the parent universe with
1538 /// To make this more concrete, consider this program:
1542 /// fn bar<T>(x: T) {
1543 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1547 /// The struct name `Foo` is in the root universe U0. But the type
1548 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1549 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1550 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1551 /// region `'a` is in a universe U2 that extends U1, because we can
1552 /// name it inside the fn type but not outside.
1554 /// Universes are used to do type- and trait-checking around these
1555 /// "forall" binders (also called **universal quantification**). The
1556 /// idea is that when, in the body of `bar`, we refer to `T` as a
1557 /// type, we aren't referring to any type in particular, but rather a
1558 /// kind of "fresh" type that is distinct from all other types we have
1559 /// actually declared. This is called a **placeholder** type, and we
1560 /// use universes to talk about this. In other words, a type name in
1561 /// universe 0 always corresponds to some "ground" type that the user
1562 /// declared, but a type name in a non-zero universe is a placeholder
1563 /// type -- an idealized representative of "types in general" that we
1564 /// use for checking generic functions.
1565 pub struct UniverseIndex {
1566 DEBUG_FORMAT = "U{}",
1570 impl_stable_hash_for!(struct UniverseIndex { private });
1572 impl UniverseIndex {
1573 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1575 /// Returns the "next" universe index in order -- this new index
1576 /// is considered to extend all previous universes. This
1577 /// corresponds to entering a `forall` quantifier. So, for
1578 /// example, suppose we have this type in universe `U`:
1581 /// for<'a> fn(&'a u32)
1584 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1585 /// new universe that extends `U` -- in this new universe, we can
1586 /// name the region `'a`, but that region was not nameable from
1587 /// `U` because it was not in scope there.
1588 pub fn next_universe(self) -> UniverseIndex {
1589 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1592 /// Returns `true` if `self` can name a name from `other` -- in other words,
1593 /// if the set of names in `self` is a superset of those in
1594 /// `other` (`self >= other`).
1595 pub fn can_name(self, other: UniverseIndex) -> bool {
1596 self.private >= other.private
1599 /// Returns `true` if `self` cannot name some names from `other` -- in other
1600 /// words, if the set of names in `self` is a strict subset of
1601 /// those in `other` (`self < other`).
1602 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1603 self.private < other.private
1607 /// The "placeholder index" fully defines a placeholder region.
1608 /// Placeholder regions are identified by both a **universe** as well
1609 /// as a "bound-region" within that universe. The `bound_region` is
1610 /// basically a name -- distinct bound regions within the same
1611 /// universe are just two regions with an unknown relationship to one
1613 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1614 pub struct Placeholder<T> {
1615 pub universe: UniverseIndex,
1619 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1620 where T: HashStable<StableHashingContext<'a>>
1622 fn hash_stable<W: StableHasherResult>(
1624 hcx: &mut StableHashingContext<'a>,
1625 hasher: &mut StableHasher<W>
1627 self.universe.hash_stable(hcx, hasher);
1628 self.name.hash_stable(hcx, hasher);
1632 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1634 pub type PlaceholderType = Placeholder<BoundVar>;
1636 pub type PlaceholderConst = Placeholder<BoundVar>;
1638 /// When type checking, we use the `ParamEnv` to track
1639 /// details about the set of where-clauses that are in scope at this
1640 /// particular point.
1641 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1642 pub struct ParamEnv<'tcx> {
1643 /// Obligations that the caller must satisfy. This is basically
1644 /// the set of bounds on the in-scope type parameters, translated
1645 /// into Obligations, and elaborated and normalized.
1646 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1648 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1649 /// want `Reveal::All` -- note that this is always paired with an
1650 /// empty environment. To get that, use `ParamEnv::reveal()`.
1651 pub reveal: traits::Reveal,
1653 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1654 /// register that `def_id` (useful for transitioning to the chalk trait
1656 pub def_id: Option<DefId>,
1659 impl<'tcx> ParamEnv<'tcx> {
1660 /// Construct a trait environment suitable for contexts where
1661 /// there are no where-clauses in scope. Hidden types (like `impl
1662 /// Trait`) are left hidden, so this is suitable for ordinary
1665 pub fn empty() -> Self {
1666 Self::new(List::empty(), Reveal::UserFacing, None)
1669 /// Construct a trait environment with no where-clauses in scope
1670 /// where the values of all `impl Trait` and other hidden types
1671 /// are revealed. This is suitable for monomorphized, post-typeck
1672 /// environments like codegen or doing optimizations.
1674 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1675 /// or invoke `param_env.with_reveal_all()`.
1677 pub fn reveal_all() -> Self {
1678 Self::new(List::empty(), Reveal::All, None)
1681 /// Construct a trait environment with the given set of predicates.
1684 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1686 def_id: Option<DefId>
1688 ty::ParamEnv { caller_bounds, reveal, def_id }
1691 /// Returns a new parameter environment with the same clauses, but
1692 /// which "reveals" the true results of projections in all cases
1693 /// (even for associated types that are specializable). This is
1694 /// the desired behavior during codegen and certain other special
1695 /// contexts; normally though we want to use `Reveal::UserFacing`,
1696 /// which is the default.
1697 pub fn with_reveal_all(self) -> Self {
1698 ty::ParamEnv { reveal: Reveal::All, ..self }
1701 /// Returns this same environment but with no caller bounds.
1702 pub fn without_caller_bounds(self) -> Self {
1703 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1706 /// Creates a suitable environment in which to perform trait
1707 /// queries on the given value. When type-checking, this is simply
1708 /// the pair of the environment plus value. But when reveal is set to
1709 /// All, then if `value` does not reference any type parameters, we will
1710 /// pair it with the empty environment. This improves caching and is generally
1713 /// N.B., we preserve the environment when type-checking because it
1714 /// is possible for the user to have wacky where-clauses like
1715 /// `where Box<u32>: Copy`, which are clearly never
1716 /// satisfiable. We generally want to behave as if they were true,
1717 /// although the surrounding function is never reachable.
1718 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1720 Reveal::UserFacing => {
1728 if value.has_placeholders()
1729 || value.needs_infer()
1730 || value.has_param_types()
1731 || value.has_self_ty()
1739 param_env: self.without_caller_bounds(),
1748 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1749 pub struct ParamEnvAnd<'tcx, T> {
1750 pub param_env: ParamEnv<'tcx>,
1754 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1755 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1756 (self.param_env, self.value)
1760 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1761 where T: HashStable<StableHashingContext<'a>>
1763 fn hash_stable<W: StableHasherResult>(&self,
1764 hcx: &mut StableHashingContext<'a>,
1765 hasher: &mut StableHasher<W>) {
1771 param_env.hash_stable(hcx, hasher);
1772 value.hash_stable(hcx, hasher);
1776 #[derive(Copy, Clone, Debug, HashStable)]
1777 pub struct Destructor {
1778 /// The `DefId` of the destructor method
1783 #[derive(HashStable)]
1784 pub struct AdtFlags: u32 {
1785 const NO_ADT_FLAGS = 0;
1786 /// Indicates whether the ADT is an enum.
1787 const IS_ENUM = 1 << 0;
1788 /// Indicates whether the ADT is a union.
1789 const IS_UNION = 1 << 1;
1790 /// Indicates whether the ADT is a struct.
1791 const IS_STRUCT = 1 << 2;
1792 /// Indicates whether the ADT is a struct and has a constructor.
1793 const HAS_CTOR = 1 << 3;
1794 /// Indicates whether the type is a `PhantomData`.
1795 const IS_PHANTOM_DATA = 1 << 4;
1796 /// Indicates whether the type has a `#[fundamental]` attribute.
1797 const IS_FUNDAMENTAL = 1 << 5;
1798 /// Indicates whether the type is a `Box`.
1799 const IS_BOX = 1 << 6;
1800 /// Indicates whether the type is an `Arc`.
1801 const IS_ARC = 1 << 7;
1802 /// Indicates whether the type is an `Rc`.
1803 const IS_RC = 1 << 8;
1804 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1805 /// (i.e., this flag is never set unless this ADT is an enum).
1806 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1811 #[derive(HashStable)]
1812 pub struct VariantFlags: u32 {
1813 const NO_VARIANT_FLAGS = 0;
1814 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1815 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1819 /// Definition of a variant -- a struct's fields or a enum variant.
1821 pub struct VariantDef {
1822 /// `DefId` that identifies the variant itself.
1823 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1825 /// `DefId` that identifies the variant's constructor.
1826 /// If this variant is a struct variant, then this is `None`.
1827 pub ctor_def_id: Option<DefId>,
1828 /// Variant or struct name.
1830 /// Discriminant of this variant.
1831 pub discr: VariantDiscr,
1832 /// Fields of this variant.
1833 pub fields: Vec<FieldDef>,
1834 /// Type of constructor of variant.
1835 pub ctor_kind: CtorKind,
1836 /// Flags of the variant (e.g. is field list non-exhaustive)?
1837 flags: VariantFlags,
1839 pub recovered: bool,
1842 impl<'a, 'gcx, 'tcx> VariantDef {
1843 /// Creates a new `VariantDef`.
1845 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1846 /// represents an enum variant).
1848 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1849 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1851 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1852 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1853 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1854 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1855 /// built-in trait), and we do not want to load attributes twice.
1857 /// If someone speeds up attribute loading to not be a performance concern, they can
1858 /// remove this hack and use the constructor `DefId` everywhere.
1860 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1862 variant_did: Option<DefId>,
1863 ctor_def_id: Option<DefId>,
1864 discr: VariantDiscr,
1865 fields: Vec<FieldDef>,
1866 ctor_kind: CtorKind,
1872 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1873 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1874 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1877 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1878 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1879 debug!("found non-exhaustive field list for {:?}", parent_did);
1880 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1881 } else if let Some(variant_did) = variant_did {
1882 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1883 debug!("found non-exhaustive field list for {:?}", variant_did);
1884 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1889 def_id: variant_did.unwrap_or(parent_did),
1900 /// Is this field list non-exhaustive?
1902 pub fn is_field_list_non_exhaustive(&self) -> bool {
1903 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1907 impl_stable_hash_for!(struct VariantDef {
1910 ident -> (ident.name),
1918 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1919 pub enum VariantDiscr {
1920 /// Explicit value for this variant, i.e., `X = 123`.
1921 /// The `DefId` corresponds to the embedded constant.
1924 /// The previous variant's discriminant plus one.
1925 /// For efficiency reasons, the distance from the
1926 /// last `Explicit` discriminant is being stored,
1927 /// or `0` for the first variant, if it has none.
1931 #[derive(Debug, HashStable)]
1932 pub struct FieldDef {
1934 #[stable_hasher(project(name))]
1936 pub vis: Visibility,
1939 /// The definition of an abstract data type -- a struct or enum.
1941 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1943 /// `DefId` of the struct, enum or union item.
1945 /// Variants of the ADT. If this is a struct or enum, then there will be a single variant.
1946 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1947 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1949 /// Repr options provided by the user.
1950 pub repr: ReprOptions,
1953 impl PartialOrd for AdtDef {
1954 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1955 Some(self.cmp(&other))
1959 /// There should be only one AdtDef for each `did`, therefore
1960 /// it is fine to implement `Ord` only based on `did`.
1961 impl Ord for AdtDef {
1962 fn cmp(&self, other: &AdtDef) -> Ordering {
1963 self.did.cmp(&other.did)
1967 impl PartialEq for AdtDef {
1968 // AdtDef are always interned and this is part of TyS equality
1970 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1973 impl Eq for AdtDef {}
1975 impl Hash for AdtDef {
1977 fn hash<H: Hasher>(&self, s: &mut H) {
1978 (self as *const AdtDef).hash(s)
1982 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1983 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1988 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1991 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1992 fn hash_stable<W: StableHasherResult>(&self,
1993 hcx: &mut StableHashingContext<'a>,
1994 hasher: &mut StableHasher<W>) {
1996 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1999 let hash: Fingerprint = CACHE.with(|cache| {
2000 let addr = self as *const AdtDef as usize;
2001 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2009 let mut hasher = StableHasher::new();
2010 did.hash_stable(hcx, &mut hasher);
2011 variants.hash_stable(hcx, &mut hasher);
2012 flags.hash_stable(hcx, &mut hasher);
2013 repr.hash_stable(hcx, &mut hasher);
2019 hash.hash_stable(hcx, hasher);
2023 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2024 pub enum AdtKind { Struct, Union, Enum }
2026 impl Into<DataTypeKind> for AdtKind {
2027 fn into(self) -> DataTypeKind {
2029 AdtKind::Struct => DataTypeKind::Struct,
2030 AdtKind::Union => DataTypeKind::Union,
2031 AdtKind::Enum => DataTypeKind::Enum,
2037 #[derive(RustcEncodable, RustcDecodable, Default)]
2038 pub struct ReprFlags: u8 {
2039 const IS_C = 1 << 0;
2040 const IS_SIMD = 1 << 1;
2041 const IS_TRANSPARENT = 1 << 2;
2042 // Internal only for now. If true, don't reorder fields.
2043 const IS_LINEAR = 1 << 3;
2045 // Any of these flags being set prevent field reordering optimisation.
2046 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2047 ReprFlags::IS_SIMD.bits |
2048 ReprFlags::IS_LINEAR.bits;
2052 impl_stable_hash_for!(struct ReprFlags {
2056 /// Represents the repr options provided by the user,
2057 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2058 pub struct ReprOptions {
2059 pub int: Option<attr::IntType>,
2062 pub flags: ReprFlags,
2065 impl_stable_hash_for!(struct ReprOptions {
2073 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
2074 let mut flags = ReprFlags::empty();
2075 let mut size = None;
2076 let mut max_align = 0;
2077 let mut min_pack = 0;
2078 for attr in tcx.get_attrs(did).iter() {
2079 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2080 flags.insert(match r {
2081 attr::ReprC => ReprFlags::IS_C,
2082 attr::ReprPacked(pack) => {
2083 min_pack = if min_pack > 0 {
2084 cmp::min(pack, min_pack)
2090 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2091 attr::ReprSimd => ReprFlags::IS_SIMD,
2092 attr::ReprInt(i) => {
2096 attr::ReprAlign(align) => {
2097 max_align = cmp::max(align, max_align);
2104 // This is here instead of layout because the choice must make it into metadata.
2105 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2106 flags.insert(ReprFlags::IS_LINEAR);
2108 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2112 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2114 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2116 pub fn packed(&self) -> bool { self.pack > 0 }
2118 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2120 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2122 pub fn discr_type(&self) -> attr::IntType {
2123 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2126 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2127 /// layout" optimizations, such as representing `Foo<&T>` as a
2129 pub fn inhibit_enum_layout_opt(&self) -> bool {
2130 self.c() || self.int.is_some()
2133 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2134 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2135 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2136 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
2140 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2141 pub fn inhibit_union_abi_opt(&self) -> bool {
2147 impl<'a, 'gcx, 'tcx> AdtDef {
2148 /// Creates a new `AdtDef`.
2150 tcx: TyCtxt<'_, '_, '_>,
2153 variants: IndexVec<VariantIdx, VariantDef>,
2156 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2157 let mut flags = AdtFlags::NO_ADT_FLAGS;
2159 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2160 debug!("found non-exhaustive variant list for {:?}", did);
2161 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2164 flags |= match kind {
2165 AdtKind::Enum => AdtFlags::IS_ENUM,
2166 AdtKind::Union => AdtFlags::IS_UNION,
2167 AdtKind::Struct => AdtFlags::IS_STRUCT,
2170 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2171 flags |= AdtFlags::HAS_CTOR;
2174 let attrs = tcx.get_attrs(did);
2175 if attr::contains_name(&attrs, sym::fundamental) {
2176 flags |= AdtFlags::IS_FUNDAMENTAL;
2178 if Some(did) == tcx.lang_items().phantom_data() {
2179 flags |= AdtFlags::IS_PHANTOM_DATA;
2181 if Some(did) == tcx.lang_items().owned_box() {
2182 flags |= AdtFlags::IS_BOX;
2184 if Some(did) == tcx.lang_items().arc() {
2185 flags |= AdtFlags::IS_ARC;
2187 if Some(did) == tcx.lang_items().rc() {
2188 flags |= AdtFlags::IS_RC;
2199 /// Returns `true` if this is a struct.
2201 pub fn is_struct(&self) -> bool {
2202 self.flags.contains(AdtFlags::IS_STRUCT)
2205 /// Returns `true` if this is a union.
2207 pub fn is_union(&self) -> bool {
2208 self.flags.contains(AdtFlags::IS_UNION)
2211 /// Returns `true` if this is a enum.
2213 pub fn is_enum(&self) -> bool {
2214 self.flags.contains(AdtFlags::IS_ENUM)
2217 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2219 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2220 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2223 /// Returns the kind of the ADT.
2225 pub fn adt_kind(&self) -> AdtKind {
2228 } else if self.is_union() {
2235 /// Returns a description of this abstract data type.
2236 pub fn descr(&self) -> &'static str {
2237 match self.adt_kind() {
2238 AdtKind::Struct => "struct",
2239 AdtKind::Union => "union",
2240 AdtKind::Enum => "enum",
2244 /// Returns a description of a variant of this abstract data type.
2246 pub fn variant_descr(&self) -> &'static str {
2247 match self.adt_kind() {
2248 AdtKind::Struct => "struct",
2249 AdtKind::Union => "union",
2250 AdtKind::Enum => "variant",
2254 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2256 pub fn has_ctor(&self) -> bool {
2257 self.flags.contains(AdtFlags::HAS_CTOR)
2260 /// Returns `true` if this type is `#[fundamental]` for the purposes
2261 /// of coherence checking.
2263 pub fn is_fundamental(&self) -> bool {
2264 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2267 /// Returns `true` if this is `PhantomData<T>`.
2269 pub fn is_phantom_data(&self) -> bool {
2270 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2273 /// Returns `true` if this is `Arc<T>`.
2274 pub fn is_arc(&self) -> bool {
2275 self.flags.contains(AdtFlags::IS_ARC)
2278 /// Returns `true` if this is `Rc<T>`.
2279 pub fn is_rc(&self) -> bool {
2280 self.flags.contains(AdtFlags::IS_RC)
2283 /// Returns `true` if this is Box<T>.
2285 pub fn is_box(&self) -> bool {
2286 self.flags.contains(AdtFlags::IS_BOX)
2289 /// Returns `true` if this type has a destructor.
2290 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2291 self.destructor(tcx).is_some()
2294 /// Asserts this is a struct or union and returns its unique variant.
2295 pub fn non_enum_variant(&self) -> &VariantDef {
2296 assert!(self.is_struct() || self.is_union());
2297 &self.variants[VariantIdx::new(0)]
2301 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2302 tcx.predicates_of(self.did)
2305 /// Returns an iterator over all fields contained
2308 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2309 self.variants.iter().flat_map(|v| v.fields.iter())
2312 pub fn is_payloadfree(&self) -> bool {
2313 !self.variants.is_empty() &&
2314 self.variants.iter().all(|v| v.fields.is_empty())
2317 /// Return a `VariantDef` given a variant id.
2318 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2319 self.variants.iter().find(|v| v.def_id == vid)
2320 .expect("variant_with_id: unknown variant")
2323 /// Return a `VariantDef` given a constructor id.
2324 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2325 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2326 .expect("variant_with_ctor_id: unknown variant")
2329 /// Return the index of `VariantDef` given a variant id.
2330 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2331 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2332 .expect("variant_index_with_id: unknown variant").0
2335 /// Return the index of `VariantDef` given a constructor id.
2336 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2337 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2338 .expect("variant_index_with_ctor_id: unknown variant").0
2341 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2343 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2344 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2345 Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
2346 Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssociatedTy, _) | Res::SelfTy(..) |
2347 Res::SelfCtor(..) => self.non_enum_variant(),
2348 _ => bug!("unexpected res {:?} in variant_of_res", res)
2353 pub fn eval_explicit_discr(
2355 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2357 ) -> Option<Discr<'tcx>> {
2358 let param_env = ParamEnv::empty();
2359 let repr_type = self.repr.discr_type();
2360 let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), expr_did);
2361 let instance = ty::Instance::new(expr_did, substs);
2362 let cid = GlobalId {
2366 match tcx.const_eval(param_env.and(cid)) {
2368 // FIXME: Find the right type and use it instead of `val.ty` here
2369 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2370 trace!("discriminants: {} ({:?})", b, repr_type);
2376 info!("invalid enum discriminant: {:#?}", val);
2377 crate::mir::interpret::struct_error(
2378 tcx.at(tcx.def_span(expr_did)),
2379 "constant evaluation of enum discriminant resulted in non-integer",
2384 Err(ErrorHandled::Reported) => {
2385 if !expr_did.is_local() {
2386 span_bug!(tcx.def_span(expr_did),
2387 "variant discriminant evaluation succeeded \
2388 in its crate but failed locally");
2392 Err(ErrorHandled::TooGeneric) => span_bug!(
2393 tcx.def_span(expr_did),
2394 "enum discriminant depends on generic arguments",
2400 pub fn discriminants(
2402 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2403 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2404 let repr_type = self.repr.discr_type();
2405 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2406 let mut prev_discr = None::<Discr<'tcx>>;
2407 self.variants.iter_enumerated().map(move |(i, v)| {
2408 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2409 if let VariantDiscr::Explicit(expr_did) = v.discr {
2410 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2414 prev_discr = Some(discr);
2421 pub fn variant_range(&self) -> Range<VariantIdx> {
2422 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2425 /// Computes the discriminant value used by a specific variant.
2426 /// Unlike `discriminants`, this is (amortized) constant-time,
2427 /// only doing at most one query for evaluating an explicit
2428 /// discriminant (the last one before the requested variant),
2429 /// assuming there are no constant-evaluation errors there.
2431 pub fn discriminant_for_variant(&self,
2432 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2433 variant_index: VariantIdx)
2435 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2436 let explicit_value = val
2437 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2438 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2439 explicit_value.checked_add(tcx, offset as u128).0
2442 /// Yields a `DefId` for the discriminant and an offset to add to it
2443 /// Alternatively, if there is no explicit discriminant, returns the
2444 /// inferred discriminant directly.
2445 pub fn discriminant_def_for_variant(
2447 variant_index: VariantIdx,
2448 ) -> (Option<DefId>, u32) {
2449 let mut explicit_index = variant_index.as_u32();
2452 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2453 ty::VariantDiscr::Relative(0) => {
2457 ty::VariantDiscr::Relative(distance) => {
2458 explicit_index -= distance;
2460 ty::VariantDiscr::Explicit(did) => {
2461 expr_did = Some(did);
2466 (expr_did, variant_index.as_u32() - explicit_index)
2469 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2470 tcx.adt_destructor(self.did)
2473 /// Returns a list of types such that `Self: Sized` if and only
2474 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2476 /// Oddly enough, checking that the sized-constraint is `Sized` is
2477 /// actually more expressive than checking all members:
2478 /// the `Sized` trait is inductive, so an associated type that references
2479 /// `Self` would prevent its containing ADT from being `Sized`.
2481 /// Due to normalization being eager, this applies even if
2482 /// the associated type is behind a pointer (e.g., issue #31299).
2483 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2484 tcx.adt_sized_constraint(self.did).0
2487 fn sized_constraint_for_ty(&self,
2488 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2491 let result = match ty.sty {
2492 Bool | Char | Int(..) | Uint(..) | Float(..) |
2493 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2494 Array(..) | Closure(..) | Generator(..) | Never => {
2503 GeneratorWitness(..) => {
2504 // these are never sized - return the target type
2511 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2515 Adt(adt, substs) => {
2517 let adt_tys = adt.sized_constraint(tcx);
2518 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2521 .map(|ty| ty.subst(tcx, substs))
2522 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2526 Projection(..) | Opaque(..) => {
2527 // must calculate explicitly.
2528 // FIXME: consider special-casing always-Sized projections
2532 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2535 // perf hack: if there is a `T: Sized` bound, then
2536 // we know that `T` is Sized and do not need to check
2539 let sized_trait = match tcx.lang_items().sized_trait() {
2541 _ => return vec![ty]
2543 let sized_predicate = Binder::dummy(TraitRef {
2544 def_id: sized_trait,
2545 substs: tcx.mk_substs_trait(ty, &[])
2547 let predicates = &tcx.predicates_of(self.did).predicates;
2548 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2558 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2562 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2567 impl<'a, 'gcx, 'tcx> FieldDef {
2568 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2569 tcx.type_of(self.did).subst(tcx, subst)
2573 /// Represents the various closure traits in the language. This
2574 /// will determine the type of the environment (`self`, in the
2575 /// desugaring) argument that the closure expects.
2577 /// You can get the environment type of a closure using
2578 /// `tcx.closure_env_ty()`.
2579 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2580 RustcEncodable, RustcDecodable, HashStable)]
2581 pub enum ClosureKind {
2582 // Warning: Ordering is significant here! The ordering is chosen
2583 // because the trait Fn is a subtrait of FnMut and so in turn, and
2584 // hence we order it so that Fn < FnMut < FnOnce.
2590 impl<'a, 'tcx> ClosureKind {
2591 // This is the initial value used when doing upvar inference.
2592 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2594 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2596 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2597 ClosureKind::FnMut => {
2598 tcx.require_lang_item(FnMutTraitLangItem)
2600 ClosureKind::FnOnce => {
2601 tcx.require_lang_item(FnOnceTraitLangItem)
2606 /// Returns `true` if this a type that impls this closure kind
2607 /// must also implement `other`.
2608 pub fn extends(self, other: ty::ClosureKind) -> bool {
2609 match (self, other) {
2610 (ClosureKind::Fn, ClosureKind::Fn) => true,
2611 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2612 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2613 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2614 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2615 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2620 /// Returns the representative scalar type for this closure kind.
2621 /// See `TyS::to_opt_closure_kind` for more details.
2622 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2624 ty::ClosureKind::Fn => tcx.types.i8,
2625 ty::ClosureKind::FnMut => tcx.types.i16,
2626 ty::ClosureKind::FnOnce => tcx.types.i32,
2631 impl<'tcx> TyS<'tcx> {
2632 /// Iterator that walks `self` and any types reachable from
2633 /// `self`, in depth-first order. Note that just walks the types
2634 /// that appear in `self`, it does not descend into the fields of
2635 /// structs or variants. For example:
2638 /// isize => { isize }
2639 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2640 /// [isize] => { [isize], isize }
2642 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2643 TypeWalker::new(self)
2646 /// Iterator that walks the immediate children of `self`. Hence
2647 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2648 /// (but not `i32`, like `walk`).
2649 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2650 walk::walk_shallow(self)
2653 /// Walks `ty` and any types appearing within `ty`, invoking the
2654 /// callback `f` on each type. If the callback returns `false`, then the
2655 /// children of the current type are ignored.
2657 /// Note: prefer `ty.walk()` where possible.
2658 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2659 where F: FnMut(Ty<'tcx>) -> bool
2661 let mut walker = self.walk();
2662 while let Some(ty) = walker.next() {
2664 walker.skip_current_subtree();
2671 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2673 hir::MutMutable => MutBorrow,
2674 hir::MutImmutable => ImmBorrow,
2678 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2679 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2680 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2682 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2684 MutBorrow => hir::MutMutable,
2685 ImmBorrow => hir::MutImmutable,
2687 // We have no type corresponding to a unique imm borrow, so
2688 // use `&mut`. It gives all the capabilities of an `&uniq`
2689 // and hence is a safe "over approximation".
2690 UniqueImmBorrow => hir::MutMutable,
2694 pub fn to_user_str(&self) -> &'static str {
2696 MutBorrow => "mutable",
2697 ImmBorrow => "immutable",
2698 UniqueImmBorrow => "uniquely immutable",
2703 #[derive(Debug, Clone)]
2704 pub enum Attributes<'gcx> {
2705 Owned(Lrc<[ast::Attribute]>),
2706 Borrowed(&'gcx [ast::Attribute])
2709 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2710 type Target = [ast::Attribute];
2712 fn deref(&self) -> &[ast::Attribute] {
2714 &Attributes::Owned(ref data) => &data,
2715 &Attributes::Borrowed(data) => data
2720 #[derive(Debug, PartialEq, Eq)]
2721 pub enum ImplOverlapKind {
2722 /// These impls are always allowed to overlap.
2724 /// These impls are allowed to overlap, but that raises
2725 /// an issue #33140 future-compatibility warning.
2727 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2728 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2730 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2731 /// that difference, making what reduces to the following set of impls:
2735 /// impl Trait for dyn Send + Sync {}
2736 /// impl Trait for dyn Sync + Send {}
2739 /// Obviously, once we made these types be identical, that code causes a coherence
2740 /// error and a fairly big headache for us. However, luckily for us, the trait
2741 /// `Trait` used in this case is basically a marker trait, and therefore having
2742 /// overlapping impls for it is sound.
2744 /// To handle this, we basically regard the trait as a marker trait, with an additional
2745 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2746 /// it has the following restrictions:
2748 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2750 /// 2. The trait-ref of both impls must be equal.
2751 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2753 /// 4. Neither of the impls can have any where-clauses.
2755 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2759 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2760 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2761 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2764 /// Returns an iterator of the `DefId`s for all body-owners in this
2765 /// crate. If you would prefer to iterate over the bodies
2766 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2769 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2773 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2776 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2777 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2778 f(self.hir().body_owner_def_id(body_id))
2782 pub fn expr_span(self, id: NodeId) -> Span {
2783 match self.hir().find(id) {
2784 Some(Node::Expr(e)) => {
2788 bug!("Node id {} is not an expr: {:?}", id, f);
2791 bug!("Node id {} is not present in the node map", id);
2796 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2797 self.associated_items(id)
2798 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2802 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2803 self.associated_items(did).any(|item| {
2804 item.relevant_for_never()
2808 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2809 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2810 match self.hir().get_by_hir_id(hir_id) {
2811 Node::TraitItem(_) | Node::ImplItem(_) => true,
2815 match self.def_kind(def_id).expect("no def for def-id") {
2816 DefKind::AssociatedConst
2818 | DefKind::AssociatedTy => true,
2823 if is_associated_item {
2824 Some(self.associated_item(def_id))
2830 fn associated_item_from_trait_item_ref(self,
2831 parent_def_id: DefId,
2832 parent_vis: &hir::Visibility,
2833 trait_item_ref: &hir::TraitItemRef)
2835 let def_id = self.hir().local_def_id_from_hir_id(trait_item_ref.id.hir_id);
2836 let (kind, has_self) = match trait_item_ref.kind {
2837 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2838 hir::AssociatedItemKind::Method { has_self } => {
2839 (ty::AssociatedKind::Method, has_self)
2841 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2842 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2846 ident: trait_item_ref.ident,
2848 // Visibility of trait items is inherited from their traits.
2849 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2850 defaultness: trait_item_ref.defaultness,
2852 container: TraitContainer(parent_def_id),
2853 method_has_self_argument: has_self
2857 fn associated_item_from_impl_item_ref(self,
2858 parent_def_id: DefId,
2859 impl_item_ref: &hir::ImplItemRef)
2861 let def_id = self.hir().local_def_id_from_hir_id(impl_item_ref.id.hir_id);
2862 let (kind, has_self) = match impl_item_ref.kind {
2863 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2864 hir::AssociatedItemKind::Method { has_self } => {
2865 (ty::AssociatedKind::Method, has_self)
2867 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2868 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2872 ident: impl_item_ref.ident,
2874 // Visibility of trait impl items doesn't matter.
2875 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2876 defaultness: impl_item_ref.defaultness,
2878 container: ImplContainer(parent_def_id),
2879 method_has_self_argument: has_self
2883 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2884 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2887 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2888 variant.fields.iter().position(|field| {
2889 self.adjust_ident(ident, variant.def_id, hir::DUMMY_HIR_ID).0 == field.ident.modern()
2893 pub fn associated_items(
2896 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2897 // Ideally, we would use `-> impl Iterator` here, but it falls
2898 // afoul of the conservative "capture [restrictions]" we put
2899 // in place, so we use a hand-written iterator.
2901 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2902 AssociatedItemsIterator {
2904 def_ids: self.associated_item_def_ids(def_id),
2909 /// Returns `true` if the impls are the same polarity and the trait either
2910 /// has no items or is annotated #[marker] and prevents item overrides.
2911 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2912 -> Option<ImplOverlapKind>
2914 let is_legit = if self.features().overlapping_marker_traits {
2915 let trait1_is_empty = self.impl_trait_ref(def_id1)
2916 .map_or(false, |trait_ref| {
2917 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2919 let trait2_is_empty = self.impl_trait_ref(def_id2)
2920 .map_or(false, |trait_ref| {
2921 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2923 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2927 let is_marker_impl = |def_id: DefId| -> bool {
2928 let trait_ref = self.impl_trait_ref(def_id);
2929 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2931 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2932 && is_marker_impl(def_id1)
2933 && is_marker_impl(def_id2)
2937 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
2939 Some(ImplOverlapKind::Permitted)
2941 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2942 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2943 if self_ty1 == self_ty2 {
2944 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2946 return Some(ImplOverlapKind::Issue33140);
2948 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2949 def_id1, def_id2, self_ty1, self_ty2);
2954 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2960 /// Returns `ty::VariantDef` if `res` refers to a struct,
2961 /// or variant or their constructors, panics otherwise.
2962 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2964 Res::Def(DefKind::Variant, did) => {
2965 let enum_did = self.parent(did).unwrap();
2966 self.adt_def(enum_did).variant_with_id(did)
2968 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
2969 self.adt_def(did).non_enum_variant()
2971 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2972 let variant_did = self.parent(variant_ctor_did).unwrap();
2973 let enum_did = self.parent(variant_did).unwrap();
2974 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2976 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2977 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2978 self.adt_def(struct_did).non_enum_variant()
2980 _ => bug!("expect_variant_res used with unexpected res {:?}", res)
2984 pub fn item_name(self, id: DefId) -> InternedString {
2985 if id.index == CRATE_DEF_INDEX {
2986 self.original_crate_name(id.krate).as_interned_str()
2988 let def_key = self.def_key(id);
2989 match def_key.disambiguated_data.data {
2990 // The name of a constructor is that of its parent.
2991 hir_map::DefPathData::Ctor =>
2992 self.item_name(DefId {
2994 index: def_key.parent.unwrap()
2996 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2997 bug!("item_name: no name for {:?}", self.def_path(id));
3003 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
3004 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
3008 ty::InstanceDef::Item(did) => {
3009 self.optimized_mir(did)
3011 ty::InstanceDef::VtableShim(..) |
3012 ty::InstanceDef::Intrinsic(..) |
3013 ty::InstanceDef::FnPtrShim(..) |
3014 ty::InstanceDef::Virtual(..) |
3015 ty::InstanceDef::ClosureOnceShim { .. } |
3016 ty::InstanceDef::DropGlue(..) |
3017 ty::InstanceDef::CloneShim(..) => {
3018 self.mir_shims(instance)
3023 /// Gets the attributes of a definition.
3024 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
3025 if let Some(id) = self.hir().as_local_hir_id(did) {
3026 Attributes::Borrowed(self.hir().attrs_by_hir_id(id))
3028 Attributes::Owned(self.item_attrs(did))
3032 /// Determines whether an item is annotated with an attribute.
3033 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
3034 attr::contains_name(&self.get_attrs(did), attr)
3037 /// Returns `true` if this is an `auto trait`.
3038 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3039 self.trait_def(trait_def_id).has_auto_impl
3042 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3043 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3046 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3047 /// If it implements no trait, returns `None`.
3048 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3049 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3052 /// If the given defid describes a method belonging to an impl, returns the
3053 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3054 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3055 let item = if def_id.krate != LOCAL_CRATE {
3056 if let Some(DefKind::Method) = self.def_kind(def_id) {
3057 Some(self.associated_item(def_id))
3062 self.opt_associated_item(def_id)
3065 item.and_then(|trait_item|
3066 match trait_item.container {
3067 TraitContainer(_) => None,
3068 ImplContainer(def_id) => Some(def_id),
3073 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3074 /// with the name of the crate containing the impl.
3075 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3076 if impl_did.is_local() {
3077 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3078 Ok(self.hir().span_by_hir_id(hir_id))
3080 Err(self.crate_name(impl_did.krate))
3084 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3085 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3086 /// definition's parent/scope to perform comparison.
3087 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3088 self.adjust_ident(use_name, def_parent_def_id, hir::DUMMY_HIR_ID).0 == def_name.modern()
3091 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: hir::HirId) -> (Ident, DefId) {
3092 ident = ident.modern();
3093 let target_expansion = match scope.krate {
3094 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3097 let scope = match ident.span.adjust(target_expansion) {
3098 Some(actual_expansion) =>
3099 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3100 None if block == hir::DUMMY_HIR_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
3101 None => self.hir().get_module_parent_by_hir_id(block),
3107 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
3108 tcx: TyCtxt<'a, 'gcx, 'tcx>,
3109 def_ids: Lrc<Vec<DefId>>,
3113 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
3114 type Item = AssociatedItem;
3116 fn next(&mut self) -> Option<AssociatedItem> {
3117 let def_id = self.def_ids.get(self.next_index)?;
3118 self.next_index += 1;
3119 Some(self.tcx.associated_item(*def_id))
3123 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
3124 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3125 let parent_id = tcx.hir().get_parent_item(id);
3126 let parent_def_id = tcx.hir().local_def_id_from_hir_id(parent_id);
3127 let parent_item = tcx.hir().expect_item_by_hir_id(parent_id);
3128 match parent_item.node {
3129 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3130 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3131 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3133 debug_assert_eq!(assoc_item.def_id, def_id);
3138 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3139 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3140 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3143 debug_assert_eq!(assoc_item.def_id, def_id);
3151 span_bug!(parent_item.span,
3152 "unexpected parent of trait or impl item or item not found: {:?}",
3156 #[derive(Clone, HashStable)]
3157 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3159 /// Calculates the `Sized` constraint.
3161 /// In fact, there are only a few options for the types in the constraint:
3162 /// - an obviously-unsized type
3163 /// - a type parameter or projection whose Sizedness can't be known
3164 /// - a tuple of type parameters or projections, if there are multiple
3166 /// - a Error, if a type contained itself. The representability
3167 /// check should catch this case.
3168 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3170 -> AdtSizedConstraint<'tcx> {
3171 let def = tcx.adt_def(def_id);
3173 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3176 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3179 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3181 AdtSizedConstraint(result)
3184 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3186 -> Lrc<Vec<DefId>> {
3187 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3188 let item = tcx.hir().expect_item_by_hir_id(id);
3189 let vec: Vec<_> = match item.node {
3190 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3191 trait_item_refs.iter()
3192 .map(|trait_item_ref| trait_item_ref.id)
3193 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3196 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3197 impl_item_refs.iter()
3198 .map(|impl_item_ref| impl_item_ref.id)
3199 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3202 hir::ItemKind::TraitAlias(..) => vec![],
3203 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3208 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3209 tcx.hir().span_if_local(def_id).unwrap()
3212 /// If the given `DefId` describes an item belonging to a trait,
3213 /// returns the `DefId` of the trait that the trait item belongs to;
3214 /// otherwise, returns `None`.
3215 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3216 tcx.opt_associated_item(def_id)
3217 .and_then(|associated_item| {
3218 match associated_item.container {
3219 TraitContainer(def_id) => Some(def_id),
3220 ImplContainer(_) => None
3225 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3226 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3227 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3228 if let Node::Item(item) = tcx.hir().get_by_hir_id(hir_id) {
3229 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3230 return exist_ty.impl_trait_fn;
3237 /// See `ParamEnv` struct definition for details.
3238 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3242 // The param_env of an impl Trait type is its defining function's param_env
3243 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3244 return param_env(tcx, parent);
3246 // Compute the bounds on Self and the type parameters.
3248 let InstantiatedPredicates { predicates } =
3249 tcx.predicates_of(def_id).instantiate_identity(tcx);
3251 // Finally, we have to normalize the bounds in the environment, in
3252 // case they contain any associated type projections. This process
3253 // can yield errors if the put in illegal associated types, like
3254 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3255 // report these errors right here; this doesn't actually feel
3256 // right to me, because constructing the environment feels like a
3257 // kind of a "idempotent" action, but I'm not sure where would be
3258 // a better place. In practice, we construct environments for
3259 // every fn once during type checking, and we'll abort if there
3260 // are any errors at that point, so after type checking you can be
3261 // sure that this will succeed without errors anyway.
3263 let unnormalized_env = ty::ParamEnv::new(
3264 tcx.intern_predicates(&predicates),
3265 traits::Reveal::UserFacing,
3266 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3269 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3270 tcx.hir().maybe_body_owned_by_by_hir_id(id).map_or(id, |body| body.hir_id)
3272 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3273 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3276 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3277 crate_num: CrateNum) -> CrateDisambiguator {
3278 assert_eq!(crate_num, LOCAL_CRATE);
3279 tcx.sess.local_crate_disambiguator()
3282 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3283 crate_num: CrateNum) -> Symbol {
3284 assert_eq!(crate_num, LOCAL_CRATE);
3285 tcx.crate_name.clone()
3288 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3289 crate_num: CrateNum)
3291 assert_eq!(crate_num, LOCAL_CRATE);
3292 tcx.hir().crate_hash
3295 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3296 instance_def: InstanceDef<'tcx>)
3298 match instance_def {
3299 InstanceDef::Item(..) |
3300 InstanceDef::DropGlue(..) => {
3301 let mir = tcx.instance_mir(instance_def);
3302 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3304 // Estimate the size of other compiler-generated shims to be 1.
3309 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3311 /// See [`ImplOverlapKind::Issue33140`] for more details.
3312 fn issue33140_self_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3316 debug!("issue33140_self_ty({:?})", def_id);
3318 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3319 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3322 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3324 let is_marker_like =
3325 tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
3326 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3328 // Check whether these impls would be ok for a marker trait.
3329 if !is_marker_like {
3330 debug!("issue33140_self_ty - not marker-like!");
3334 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3335 if trait_ref.substs.len() != 1 {
3336 debug!("issue33140_self_ty - impl has substs!");
3340 let predicates = tcx.predicates_of(def_id);
3341 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3342 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3346 let self_ty = trait_ref.self_ty();
3347 let self_ty_matches = match self_ty.sty {
3348 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3352 if self_ty_matches {
3353 debug!("issue33140_self_ty - MATCHES!");
3356 debug!("issue33140_self_ty - non-matching self type");
3361 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3362 context::provide(providers);
3363 erase_regions::provide(providers);
3364 layout::provide(providers);
3365 util::provide(providers);
3366 constness::provide(providers);
3367 *providers = ty::query::Providers {
3369 associated_item_def_ids,
3370 adt_sized_constraint,
3374 crate_disambiguator,
3375 original_crate_name,
3377 trait_impls_of: trait_def::trait_impls_of_provider,
3378 instance_def_size_estimate,
3384 /// A map for the local crate mapping each type to a vector of its
3385 /// inherent impls. This is not meant to be used outside of coherence;
3386 /// rather, you should request the vector for a specific type via
3387 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3388 /// (constructing this map requires touching the entire crate).
3389 #[derive(Clone, Debug, Default, HashStable)]
3390 pub struct CrateInherentImpls {
3391 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3394 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3395 pub struct SymbolName {
3396 // FIXME: we don't rely on interning or equality here - better have
3397 // this be a `&'tcx str`.
3398 pub name: InternedString
3401 impl_stable_hash_for!(struct self::SymbolName {
3406 pub fn new(name: &str) -> SymbolName {
3408 name: InternedString::intern(name)
3412 pub fn as_str(&self) -> LocalInternedString {
3417 impl fmt::Display for SymbolName {
3418 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3419 fmt::Display::fmt(&self.name, fmt)
3423 impl fmt::Debug for SymbolName {
3424 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3425 fmt::Display::fmt(&self.name, fmt)