1 // ignore-tidy-filelength
3 #![allow(usage_of_ty_tykind)]
5 pub use self::Variance::*;
6 pub use self::AssocItemContainer::*;
7 pub use self::BorrowKind::*;
8 pub use self::IntVarValue::*;
9 pub use self::fold::TypeFoldable;
11 use crate::hir::{map as hir_map, 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::{kw, sym, Symbol, LocalInternedString, InternedString};
54 use rustc_data_structures::fx::FxIndexMap;
55 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
56 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
61 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
62 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
63 pub use self::sty::{InferTy, ParamTy, ParamConst, InferConst, ProjectionTy, ExistentialPredicate};
64 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
65 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
66 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
67 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
68 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
69 pub use self::sty::RegionKind;
70 pub use self::sty::{TyVid, IntVid, FloatVid, ConstVid, RegionVid};
71 pub use self::sty::BoundRegion::*;
72 pub use self::sty::InferTy::*;
73 pub use self::sty::RegionKind::*;
74 pub use self::sty::TyKind::*;
76 pub use self::binding::BindingMode;
77 pub use self::binding::BindingMode::*;
79 pub use self::context::{TyCtxt, FreeRegionInfo, AllArenas, tls, keep_local};
80 pub use self::context::{Lift, TypeckTables, CtxtInterners, GlobalCtxt};
81 pub use self::context::{
82 UserTypeAnnotationIndex, UserType, CanonicalUserType,
83 CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
86 pub use self::instance::{Instance, InstanceDef};
88 pub use self::trait_def::TraitDef;
90 pub use self::query::queries;
103 pub mod inhabitedness;
119 mod structural_impls;
125 pub struct Resolutions {
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 AssocItemContainer {
138 TraitContainer(DefId),
139 ImplContainer(DefId),
142 impl AssocItemContainer {
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 AssocItem {
174 #[stable_hasher(project(name))]
178 pub defaultness: hir::Defaultness,
179 pub container: AssocItemContainer,
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)]
195 pub fn def_kind(&self) -> DefKind {
197 AssocKind::Const => DefKind::AssocConst,
198 AssocKind::Method => DefKind::Method,
199 AssocKind::Type => DefKind::AssocTy,
200 AssocKind::Existential => DefKind::AssocExistential,
204 /// Tests whether the associated item admits a non-trivial implementation
206 pub fn relevant_for_never(&self) -> bool {
208 AssocKind::Existential |
210 AssocKind::Type => true,
211 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
212 AssocKind::Method => !self.method_has_self_argument,
216 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
218 ty::AssocKind::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::AssocKind::Type => format!("type {};", self.ident),
226 ty::AssocKind::Existential => format!("existential type {};", self.ident),
227 ty::AssocKind::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<'tcx> DefIdTree for TyCtxt<'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(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_size!(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, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
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<'tcx> = Canonical<'tcx, Ty<'tcx>>;
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, FxIndexMap<hir::HirId, 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 != kw::UnderscoreLifetime.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<'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<'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 => {}
962 param: &EarlyBoundRegion,
964 ) -> &'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, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
979 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
980 let param = &self.params[index as usize];
982 GenericParamDefKind::Type { .. } => param,
983 _ => bug!("expected type parameter, but found another generic parameter")
986 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
987 .type_param(param, tcx)
991 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
992 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
993 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
994 let param = &self.params[index as usize];
996 GenericParamDefKind::Const => param,
997 _ => bug!("expected const parameter, but found another generic parameter")
1000 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1001 .const_param(param, tcx)
1006 /// Bounds on generics.
1007 #[derive(Clone, Default, Debug, HashStable)]
1008 pub struct GenericPredicates<'tcx> {
1009 pub parent: Option<DefId>,
1010 pub predicates: Vec<(Predicate<'tcx>, Span)>,
1013 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
1014 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
1016 impl<'tcx> GenericPredicates<'tcx> {
1020 substs: SubstsRef<'tcx>,
1021 ) -> InstantiatedPredicates<'tcx> {
1022 let mut instantiated = InstantiatedPredicates::empty();
1023 self.instantiate_into(tcx, &mut instantiated, substs);
1027 pub fn instantiate_own(
1030 substs: SubstsRef<'tcx>,
1031 ) -> InstantiatedPredicates<'tcx> {
1032 InstantiatedPredicates {
1033 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1037 fn instantiate_into(
1040 instantiated: &mut InstantiatedPredicates<'tcx>,
1041 substs: SubstsRef<'tcx>,
1043 if let Some(def_id) = self.parent {
1044 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1046 instantiated.predicates.extend(
1047 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1051 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
1052 let mut instantiated = InstantiatedPredicates::empty();
1053 self.instantiate_identity_into(tcx, &mut instantiated);
1057 fn instantiate_identity_into(
1060 instantiated: &mut InstantiatedPredicates<'tcx>,
1062 if let Some(def_id) = self.parent {
1063 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1065 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1068 pub fn instantiate_supertrait(
1071 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1072 ) -> InstantiatedPredicates<'tcx> {
1073 assert_eq!(self.parent, None);
1074 InstantiatedPredicates {
1075 predicates: self.predicates.iter().map(|(pred, _)| {
1076 pred.subst_supertrait(tcx, poly_trait_ref)
1082 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1083 pub enum Predicate<'tcx> {
1084 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1085 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1086 /// would be the type parameters.
1087 Trait(PolyTraitPredicate<'tcx>),
1090 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1093 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1095 /// `where <T as TraitRef>::Name == X`, approximately.
1096 /// See the `ProjectionPredicate` struct for details.
1097 Projection(PolyProjectionPredicate<'tcx>),
1099 /// No syntax: `T` well-formed.
1100 WellFormed(Ty<'tcx>),
1102 /// Trait must be object-safe.
1105 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1106 /// for some substitutions `...` and `T` being a closure type.
1107 /// Satisfied (or refuted) once we know the closure's kind.
1108 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1111 Subtype(PolySubtypePredicate<'tcx>),
1113 /// Constant initializer must evaluate successfully.
1114 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1117 /// The crate outlives map is computed during typeck and contains the
1118 /// outlives of every item in the local crate. You should not use it
1119 /// directly, because to do so will make your pass dependent on the
1120 /// HIR of every item in the local crate. Instead, use
1121 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1123 #[derive(HashStable)]
1124 pub struct CratePredicatesMap<'tcx> {
1125 /// For each struct with outlive bounds, maps to a vector of the
1126 /// predicate of its outlive bounds. If an item has no outlives
1127 /// bounds, it will have no entry.
1128 pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
1131 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1132 fn as_ref(&self) -> &Predicate<'tcx> {
1137 impl<'tcx> Predicate<'tcx> {
1138 /// Performs a substitution suitable for going from a
1139 /// poly-trait-ref to supertraits that must hold if that
1140 /// poly-trait-ref holds. This is slightly different from a normal
1141 /// substitution in terms of what happens with bound regions. See
1142 /// lengthy comment below for details.
1143 pub fn subst_supertrait(
1146 trait_ref: &ty::PolyTraitRef<'tcx>,
1147 ) -> ty::Predicate<'tcx> {
1148 // The interaction between HRTB and supertraits is not entirely
1149 // obvious. Let me walk you (and myself) through an example.
1151 // Let's start with an easy case. Consider two traits:
1153 // trait Foo<'a>: Bar<'a,'a> { }
1154 // trait Bar<'b,'c> { }
1156 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1157 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1158 // knew that `Foo<'x>` (for any 'x) then we also know that
1159 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1160 // normal substitution.
1162 // In terms of why this is sound, the idea is that whenever there
1163 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1164 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1165 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1168 // Another example to be careful of is this:
1170 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1171 // trait Bar1<'b,'c> { }
1173 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1174 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1175 // reason is similar to the previous example: any impl of
1176 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1177 // basically we would want to collapse the bound lifetimes from
1178 // the input (`trait_ref`) and the supertraits.
1180 // To achieve this in practice is fairly straightforward. Let's
1181 // consider the more complicated scenario:
1183 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1184 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1185 // where both `'x` and `'b` would have a DB index of 1.
1186 // The substitution from the input trait-ref is therefore going to be
1187 // `'a => 'x` (where `'x` has a DB index of 1).
1188 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1189 // early-bound parameter and `'b' is a late-bound parameter with a
1191 // - If we replace `'a` with `'x` from the input, it too will have
1192 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1193 // just as we wanted.
1195 // There is only one catch. If we just apply the substitution `'a
1196 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1197 // adjust the DB index because we substituting into a binder (it
1198 // tries to be so smart...) resulting in `for<'x> for<'b>
1199 // Bar1<'x,'b>` (we have no syntax for this, so use your
1200 // imagination). Basically the 'x will have DB index of 2 and 'b
1201 // will have DB index of 1. Not quite what we want. So we apply
1202 // the substitution to the *contents* of the trait reference,
1203 // rather than the trait reference itself (put another way, the
1204 // substitution code expects equal binding levels in the values
1205 // from the substitution and the value being substituted into, and
1206 // this trick achieves that).
1208 let substs = &trait_ref.skip_binder().substs;
1210 Predicate::Trait(ref binder) =>
1211 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1212 Predicate::Subtype(ref binder) =>
1213 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1214 Predicate::RegionOutlives(ref binder) =>
1215 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1216 Predicate::TypeOutlives(ref binder) =>
1217 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1218 Predicate::Projection(ref binder) =>
1219 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1220 Predicate::WellFormed(data) =>
1221 Predicate::WellFormed(data.subst(tcx, substs)),
1222 Predicate::ObjectSafe(trait_def_id) =>
1223 Predicate::ObjectSafe(trait_def_id),
1224 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1225 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1226 Predicate::ConstEvaluatable(def_id, const_substs) =>
1227 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1232 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1233 pub struct TraitPredicate<'tcx> {
1234 pub trait_ref: TraitRef<'tcx>
1237 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1239 impl<'tcx> TraitPredicate<'tcx> {
1240 pub fn def_id(&self) -> DefId {
1241 self.trait_ref.def_id
1244 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
1245 self.trait_ref.input_types()
1248 pub fn self_ty(&self) -> Ty<'tcx> {
1249 self.trait_ref.self_ty()
1253 impl<'tcx> PolyTraitPredicate<'tcx> {
1254 pub fn def_id(&self) -> DefId {
1255 // Ok to skip binder since trait def-ID does not care about regions.
1256 self.skip_binder().def_id()
1260 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1261 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1262 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1263 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1264 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1265 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1266 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1267 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1269 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1270 pub struct SubtypePredicate<'tcx> {
1271 pub a_is_expected: bool,
1275 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1277 /// This kind of predicate has no *direct* correspondent in the
1278 /// syntax, but it roughly corresponds to the syntactic forms:
1280 /// 1. `T: TraitRef<..., Item = Type>`
1281 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1283 /// In particular, form #1 is "desugared" to the combination of a
1284 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1285 /// predicates. Form #2 is a broader form in that it also permits
1286 /// equality between arbitrary types. Processing an instance of
1287 /// Form #2 eventually yields one of these `ProjectionPredicate`
1288 /// instances to normalize the LHS.
1289 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1290 pub struct ProjectionPredicate<'tcx> {
1291 pub projection_ty: ProjectionTy<'tcx>,
1295 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1297 impl<'tcx> PolyProjectionPredicate<'tcx> {
1298 /// Returns the `DefId` of the associated item being projected.
1299 pub fn item_def_id(&self) -> DefId {
1300 self.skip_binder().projection_ty.item_def_id
1304 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_>) -> PolyTraitRef<'tcx> {
1305 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1306 // `self.0.trait_ref` is permitted to have escaping regions.
1307 // This is because here `self` has a `Binder` and so does our
1308 // return value, so we are preserving the number of binding
1310 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1313 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1314 self.map_bound(|predicate| predicate.ty)
1317 /// The `DefId` of the `TraitItem` for the associated type.
1319 /// Note that this is not the `DefId` of the `TraitRef` containing this
1320 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1321 pub fn projection_def_id(&self) -> DefId {
1322 // Ok to skip binder since trait def-ID does not care about regions.
1323 self.skip_binder().projection_ty.item_def_id
1327 pub trait ToPolyTraitRef<'tcx> {
1328 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1331 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1332 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1333 ty::Binder::dummy(self.clone())
1337 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1338 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1339 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1343 pub trait ToPredicate<'tcx> {
1344 fn to_predicate(&self) -> Predicate<'tcx>;
1347 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1348 fn to_predicate(&self) -> Predicate<'tcx> {
1349 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1350 trait_ref: self.clone()
1355 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1356 fn to_predicate(&self) -> Predicate<'tcx> {
1357 ty::Predicate::Trait(self.to_poly_trait_predicate())
1361 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1362 fn to_predicate(&self) -> Predicate<'tcx> {
1363 Predicate::RegionOutlives(self.clone())
1367 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1368 fn to_predicate(&self) -> Predicate<'tcx> {
1369 Predicate::TypeOutlives(self.clone())
1373 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1374 fn to_predicate(&self) -> Predicate<'tcx> {
1375 Predicate::Projection(self.clone())
1379 // A custom iterator used by `Predicate::walk_tys`.
1380 enum WalkTysIter<'tcx, I, J, K>
1381 where I: Iterator<Item = Ty<'tcx>>,
1382 J: Iterator<Item = Ty<'tcx>>,
1383 K: Iterator<Item = Ty<'tcx>>
1387 Two(Ty<'tcx>, Ty<'tcx>),
1393 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1394 where I: Iterator<Item = Ty<'tcx>>,
1395 J: Iterator<Item = Ty<'tcx>>,
1396 K: Iterator<Item = Ty<'tcx>>
1398 type Item = Ty<'tcx>;
1400 fn next(&mut self) -> Option<Ty<'tcx>> {
1402 WalkTysIter::None => None,
1403 WalkTysIter::One(item) => {
1404 *self = WalkTysIter::None;
1407 WalkTysIter::Two(item1, item2) => {
1408 *self = WalkTysIter::One(item2);
1411 WalkTysIter::Types(ref mut iter) => {
1414 WalkTysIter::InputTypes(ref mut iter) => {
1417 WalkTysIter::ProjectionTypes(ref mut iter) => {
1424 impl<'tcx> Predicate<'tcx> {
1425 /// Iterates over the types in this predicate. Note that in all
1426 /// cases this is skipping over a binder, so late-bound regions
1427 /// with depth 0 are bound by the predicate.
1428 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1430 ty::Predicate::Trait(ref data) => {
1431 WalkTysIter::InputTypes(data.skip_binder().input_types())
1433 ty::Predicate::Subtype(binder) => {
1434 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1435 WalkTysIter::Two(a, b)
1437 ty::Predicate::TypeOutlives(binder) => {
1438 WalkTysIter::One(binder.skip_binder().0)
1440 ty::Predicate::RegionOutlives(..) => {
1443 ty::Predicate::Projection(ref data) => {
1444 let inner = data.skip_binder();
1445 WalkTysIter::ProjectionTypes(
1446 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1448 ty::Predicate::WellFormed(data) => {
1449 WalkTysIter::One(data)
1451 ty::Predicate::ObjectSafe(_trait_def_id) => {
1454 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1455 WalkTysIter::Types(closure_substs.substs.types())
1457 ty::Predicate::ConstEvaluatable(_, substs) => {
1458 WalkTysIter::Types(substs.types())
1463 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1465 Predicate::Trait(ref t) => {
1466 Some(t.to_poly_trait_ref())
1468 Predicate::Projection(..) |
1469 Predicate::Subtype(..) |
1470 Predicate::RegionOutlives(..) |
1471 Predicate::WellFormed(..) |
1472 Predicate::ObjectSafe(..) |
1473 Predicate::ClosureKind(..) |
1474 Predicate::TypeOutlives(..) |
1475 Predicate::ConstEvaluatable(..) => {
1481 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1483 Predicate::TypeOutlives(data) => {
1486 Predicate::Trait(..) |
1487 Predicate::Projection(..) |
1488 Predicate::Subtype(..) |
1489 Predicate::RegionOutlives(..) |
1490 Predicate::WellFormed(..) |
1491 Predicate::ObjectSafe(..) |
1492 Predicate::ClosureKind(..) |
1493 Predicate::ConstEvaluatable(..) => {
1500 /// Represents the bounds declared on a particular set of type
1501 /// parameters. Should eventually be generalized into a flag list of
1502 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1503 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1504 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1505 /// the `GenericPredicates` are expressed in terms of the bound type
1506 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1507 /// represented a set of bounds for some particular instantiation,
1508 /// meaning that the generic parameters have been substituted with
1513 /// struct Foo<T, U: Bar<T>> { ... }
1515 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1516 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1517 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1518 /// [usize:Bar<isize>]]`.
1519 #[derive(Clone, Debug)]
1520 pub struct InstantiatedPredicates<'tcx> {
1521 pub predicates: Vec<Predicate<'tcx>>,
1524 impl<'tcx> InstantiatedPredicates<'tcx> {
1525 pub fn empty() -> InstantiatedPredicates<'tcx> {
1526 InstantiatedPredicates { predicates: vec![] }
1529 pub fn is_empty(&self) -> bool {
1530 self.predicates.is_empty()
1535 /// "Universes" are used during type- and trait-checking in the
1536 /// presence of `for<..>` binders to control what sets of names are
1537 /// visible. Universes are arranged into a tree: the root universe
1538 /// contains names that are always visible. Each child then adds a new
1539 /// set of names that are visible, in addition to those of its parent.
1540 /// We say that the child universe "extends" the parent universe with
1543 /// To make this more concrete, consider this program:
1547 /// fn bar<T>(x: T) {
1548 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1552 /// The struct name `Foo` is in the root universe U0. But the type
1553 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1554 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1555 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1556 /// region `'a` is in a universe U2 that extends U1, because we can
1557 /// name it inside the fn type but not outside.
1559 /// Universes are used to do type- and trait-checking around these
1560 /// "forall" binders (also called **universal quantification**). The
1561 /// idea is that when, in the body of `bar`, we refer to `T` as a
1562 /// type, we aren't referring to any type in particular, but rather a
1563 /// kind of "fresh" type that is distinct from all other types we have
1564 /// actually declared. This is called a **placeholder** type, and we
1565 /// use universes to talk about this. In other words, a type name in
1566 /// universe 0 always corresponds to some "ground" type that the user
1567 /// declared, but a type name in a non-zero universe is a placeholder
1568 /// type -- an idealized representative of "types in general" that we
1569 /// use for checking generic functions.
1570 pub struct UniverseIndex {
1571 DEBUG_FORMAT = "U{}",
1575 impl_stable_hash_for!(struct UniverseIndex { private });
1577 impl UniverseIndex {
1578 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1580 /// Returns the "next" universe index in order -- this new index
1581 /// is considered to extend all previous universes. This
1582 /// corresponds to entering a `forall` quantifier. So, for
1583 /// example, suppose we have this type in universe `U`:
1586 /// for<'a> fn(&'a u32)
1589 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1590 /// new universe that extends `U` -- in this new universe, we can
1591 /// name the region `'a`, but that region was not nameable from
1592 /// `U` because it was not in scope there.
1593 pub fn next_universe(self) -> UniverseIndex {
1594 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1597 /// Returns `true` if `self` can name a name from `other` -- in other words,
1598 /// if the set of names in `self` is a superset of those in
1599 /// `other` (`self >= other`).
1600 pub fn can_name(self, other: UniverseIndex) -> bool {
1601 self.private >= other.private
1604 /// Returns `true` if `self` cannot name some names from `other` -- in other
1605 /// words, if the set of names in `self` is a strict subset of
1606 /// those in `other` (`self < other`).
1607 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1608 self.private < other.private
1612 /// The "placeholder index" fully defines a placeholder region.
1613 /// Placeholder regions are identified by both a **universe** as well
1614 /// as a "bound-region" within that universe. The `bound_region` is
1615 /// basically a name -- distinct bound regions within the same
1616 /// universe are just two regions with an unknown relationship to one
1618 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1619 pub struct Placeholder<T> {
1620 pub universe: UniverseIndex,
1624 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1626 T: HashStable<StableHashingContext<'a>>,
1628 fn hash_stable<W: StableHasherResult>(
1630 hcx: &mut StableHashingContext<'a>,
1631 hasher: &mut StableHasher<W>
1633 self.universe.hash_stable(hcx, hasher);
1634 self.name.hash_stable(hcx, hasher);
1638 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1640 pub type PlaceholderType = Placeholder<BoundVar>;
1642 pub type PlaceholderConst = Placeholder<BoundVar>;
1644 /// When type checking, we use the `ParamEnv` to track
1645 /// details about the set of where-clauses that are in scope at this
1646 /// particular point.
1647 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1648 pub struct ParamEnv<'tcx> {
1649 /// Obligations that the caller must satisfy. This is basically
1650 /// the set of bounds on the in-scope type parameters, translated
1651 /// into Obligations, and elaborated and normalized.
1652 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1654 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1655 /// want `Reveal::All` -- note that this is always paired with an
1656 /// empty environment. To get that, use `ParamEnv::reveal()`.
1657 pub reveal: traits::Reveal,
1659 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1660 /// register that `def_id` (useful for transitioning to the chalk trait
1662 pub def_id: Option<DefId>,
1665 impl<'tcx> ParamEnv<'tcx> {
1666 /// Construct a trait environment suitable for contexts where
1667 /// there are no where-clauses in scope. Hidden types (like `impl
1668 /// Trait`) are left hidden, so this is suitable for ordinary
1671 pub fn empty() -> Self {
1672 Self::new(List::empty(), Reveal::UserFacing, None)
1675 /// Construct a trait environment with no where-clauses in scope
1676 /// where the values of all `impl Trait` and other hidden types
1677 /// are revealed. This is suitable for monomorphized, post-typeck
1678 /// environments like codegen or doing optimizations.
1680 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1681 /// or invoke `param_env.with_reveal_all()`.
1683 pub fn reveal_all() -> Self {
1684 Self::new(List::empty(), Reveal::All, None)
1687 /// Construct a trait environment with the given set of predicates.
1690 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1692 def_id: Option<DefId>
1694 ty::ParamEnv { caller_bounds, reveal, def_id }
1697 /// Returns a new parameter environment with the same clauses, but
1698 /// which "reveals" the true results of projections in all cases
1699 /// (even for associated types that are specializable). This is
1700 /// the desired behavior during codegen and certain other special
1701 /// contexts; normally though we want to use `Reveal::UserFacing`,
1702 /// which is the default.
1703 pub fn with_reveal_all(self) -> Self {
1704 ty::ParamEnv { reveal: Reveal::All, ..self }
1707 /// Returns this same environment but with no caller bounds.
1708 pub fn without_caller_bounds(self) -> Self {
1709 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1712 /// Creates a suitable environment in which to perform trait
1713 /// queries on the given value. When type-checking, this is simply
1714 /// the pair of the environment plus value. But when reveal is set to
1715 /// All, then if `value` does not reference any type parameters, we will
1716 /// pair it with the empty environment. This improves caching and is generally
1719 /// N.B., we preserve the environment when type-checking because it
1720 /// is possible for the user to have wacky where-clauses like
1721 /// `where Box<u32>: Copy`, which are clearly never
1722 /// satisfiable. We generally want to behave as if they were true,
1723 /// although the surrounding function is never reachable.
1724 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1726 Reveal::UserFacing => {
1734 if value.has_placeholders()
1735 || value.needs_infer()
1736 || value.has_param_types()
1737 || value.has_self_ty()
1745 param_env: self.without_caller_bounds(),
1754 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1755 pub struct ParamEnvAnd<'tcx, T> {
1756 pub param_env: ParamEnv<'tcx>,
1760 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1761 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1762 (self.param_env, self.value)
1766 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1768 T: HashStable<StableHashingContext<'a>>,
1770 fn hash_stable<W: StableHasherResult>(&self,
1771 hcx: &mut StableHashingContext<'a>,
1772 hasher: &mut StableHasher<W>) {
1778 param_env.hash_stable(hcx, hasher);
1779 value.hash_stable(hcx, hasher);
1783 #[derive(Copy, Clone, Debug, HashStable)]
1784 pub struct Destructor {
1785 /// The `DefId` of the destructor method
1790 #[derive(HashStable)]
1791 pub struct AdtFlags: u32 {
1792 const NO_ADT_FLAGS = 0;
1793 /// Indicates whether the ADT is an enum.
1794 const IS_ENUM = 1 << 0;
1795 /// Indicates whether the ADT is a union.
1796 const IS_UNION = 1 << 1;
1797 /// Indicates whether the ADT is a struct.
1798 const IS_STRUCT = 1 << 2;
1799 /// Indicates whether the ADT is a struct and has a constructor.
1800 const HAS_CTOR = 1 << 3;
1801 /// Indicates whether the type is a `PhantomData`.
1802 const IS_PHANTOM_DATA = 1 << 4;
1803 /// Indicates whether the type has a `#[fundamental]` attribute.
1804 const IS_FUNDAMENTAL = 1 << 5;
1805 /// Indicates whether the type is a `Box`.
1806 const IS_BOX = 1 << 6;
1807 /// Indicates whether the type is an `Arc`.
1808 const IS_ARC = 1 << 7;
1809 /// Indicates whether the type is an `Rc`.
1810 const IS_RC = 1 << 8;
1811 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1812 /// (i.e., this flag is never set unless this ADT is an enum).
1813 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1818 #[derive(HashStable)]
1819 pub struct VariantFlags: u32 {
1820 const NO_VARIANT_FLAGS = 0;
1821 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1822 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1826 /// Definition of a variant -- a struct's fields or a enum variant.
1828 pub struct VariantDef {
1829 /// `DefId` that identifies the variant itself.
1830 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1832 /// `DefId` that identifies the variant's constructor.
1833 /// If this variant is a struct variant, then this is `None`.
1834 pub ctor_def_id: Option<DefId>,
1835 /// Variant or struct name.
1837 /// Discriminant of this variant.
1838 pub discr: VariantDiscr,
1839 /// Fields of this variant.
1840 pub fields: Vec<FieldDef>,
1841 /// Type of constructor of variant.
1842 pub ctor_kind: CtorKind,
1843 /// Flags of the variant (e.g. is field list non-exhaustive)?
1844 flags: VariantFlags,
1846 pub recovered: bool,
1849 impl<'tcx> VariantDef {
1850 /// Creates a new `VariantDef`.
1852 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1853 /// represents an enum variant).
1855 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1856 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1858 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1859 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1860 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1861 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1862 /// built-in trait), and we do not want to load attributes twice.
1864 /// If someone speeds up attribute loading to not be a performance concern, they can
1865 /// remove this hack and use the constructor `DefId` everywhere.
1869 variant_did: Option<DefId>,
1870 ctor_def_id: Option<DefId>,
1871 discr: VariantDiscr,
1872 fields: Vec<FieldDef>,
1873 ctor_kind: CtorKind,
1879 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1880 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1881 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1884 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1885 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1886 debug!("found non-exhaustive field list for {:?}", parent_did);
1887 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1888 } else if let Some(variant_did) = variant_did {
1889 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1890 debug!("found non-exhaustive field list for {:?}", variant_did);
1891 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1896 def_id: variant_did.unwrap_or(parent_did),
1907 /// Is this field list non-exhaustive?
1909 pub fn is_field_list_non_exhaustive(&self) -> bool {
1910 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1914 impl_stable_hash_for!(struct VariantDef {
1917 ident -> (ident.name),
1925 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1926 pub enum VariantDiscr {
1927 /// Explicit value for this variant, i.e., `X = 123`.
1928 /// The `DefId` corresponds to the embedded constant.
1931 /// The previous variant's discriminant plus one.
1932 /// For efficiency reasons, the distance from the
1933 /// last `Explicit` discriminant is being stored,
1934 /// or `0` for the first variant, if it has none.
1938 #[derive(Debug, HashStable)]
1939 pub struct FieldDef {
1941 #[stable_hasher(project(name))]
1943 pub vis: Visibility,
1946 /// The definition of an abstract data type -- a struct or enum.
1948 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1950 /// `DefId` of the struct, enum or union item.
1952 /// Variants of the ADT. If this is a struct or enum, then there will be a single variant.
1953 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1954 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1956 /// Repr options provided by the user.
1957 pub repr: ReprOptions,
1960 impl PartialOrd for AdtDef {
1961 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1962 Some(self.cmp(&other))
1966 /// There should be only one AdtDef for each `did`, therefore
1967 /// it is fine to implement `Ord` only based on `did`.
1968 impl Ord for AdtDef {
1969 fn cmp(&self, other: &AdtDef) -> Ordering {
1970 self.did.cmp(&other.did)
1974 impl PartialEq for AdtDef {
1975 // AdtDef are always interned and this is part of TyS equality
1977 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1980 impl Eq for AdtDef {}
1982 impl Hash for AdtDef {
1984 fn hash<H: Hasher>(&self, s: &mut H) {
1985 (self as *const AdtDef).hash(s)
1989 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1990 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1995 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1998 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1999 fn hash_stable<W: StableHasherResult>(&self,
2000 hcx: &mut StableHashingContext<'a>,
2001 hasher: &mut StableHasher<W>) {
2003 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
2006 let hash: Fingerprint = CACHE.with(|cache| {
2007 let addr = self as *const AdtDef as usize;
2008 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2016 let mut hasher = StableHasher::new();
2017 did.hash_stable(hcx, &mut hasher);
2018 variants.hash_stable(hcx, &mut hasher);
2019 flags.hash_stable(hcx, &mut hasher);
2020 repr.hash_stable(hcx, &mut hasher);
2026 hash.hash_stable(hcx, hasher);
2030 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2031 pub enum AdtKind { Struct, Union, Enum }
2033 impl Into<DataTypeKind> for AdtKind {
2034 fn into(self) -> DataTypeKind {
2036 AdtKind::Struct => DataTypeKind::Struct,
2037 AdtKind::Union => DataTypeKind::Union,
2038 AdtKind::Enum => DataTypeKind::Enum,
2044 #[derive(RustcEncodable, RustcDecodable, Default)]
2045 pub struct ReprFlags: u8 {
2046 const IS_C = 1 << 0;
2047 const IS_SIMD = 1 << 1;
2048 const IS_TRANSPARENT = 1 << 2;
2049 // Internal only for now. If true, don't reorder fields.
2050 const IS_LINEAR = 1 << 3;
2052 // Any of these flags being set prevent field reordering optimisation.
2053 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2054 ReprFlags::IS_SIMD.bits |
2055 ReprFlags::IS_LINEAR.bits;
2059 impl_stable_hash_for!(struct ReprFlags {
2063 /// Represents the repr options provided by the user,
2064 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2065 pub struct ReprOptions {
2066 pub int: Option<attr::IntType>,
2069 pub flags: ReprFlags,
2072 impl_stable_hash_for!(struct ReprOptions {
2080 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2081 let mut flags = ReprFlags::empty();
2082 let mut size = None;
2083 let mut max_align = 0;
2084 let mut min_pack = 0;
2085 for attr in tcx.get_attrs(did).iter() {
2086 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2087 flags.insert(match r {
2088 attr::ReprC => ReprFlags::IS_C,
2089 attr::ReprPacked(pack) => {
2090 min_pack = if min_pack > 0 {
2091 cmp::min(pack, min_pack)
2097 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2098 attr::ReprSimd => ReprFlags::IS_SIMD,
2099 attr::ReprInt(i) => {
2103 attr::ReprAlign(align) => {
2104 max_align = cmp::max(align, max_align);
2111 // This is here instead of layout because the choice must make it into metadata.
2112 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2113 flags.insert(ReprFlags::IS_LINEAR);
2115 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2119 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2121 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2123 pub fn packed(&self) -> bool { self.pack > 0 }
2125 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2127 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2129 pub fn discr_type(&self) -> attr::IntType {
2130 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2133 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2134 /// layout" optimizations, such as representing `Foo<&T>` as a
2136 pub fn inhibit_enum_layout_opt(&self) -> bool {
2137 self.c() || self.int.is_some()
2140 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2141 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2142 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2143 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
2147 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2148 pub fn inhibit_union_abi_opt(&self) -> bool {
2154 /// Creates a new `AdtDef`.
2159 variants: IndexVec<VariantIdx, VariantDef>,
2162 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2163 let mut flags = AdtFlags::NO_ADT_FLAGS;
2165 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2166 debug!("found non-exhaustive variant list for {:?}", did);
2167 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2170 flags |= match kind {
2171 AdtKind::Enum => AdtFlags::IS_ENUM,
2172 AdtKind::Union => AdtFlags::IS_UNION,
2173 AdtKind::Struct => AdtFlags::IS_STRUCT,
2176 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2177 flags |= AdtFlags::HAS_CTOR;
2180 let attrs = tcx.get_attrs(did);
2181 if attr::contains_name(&attrs, sym::fundamental) {
2182 flags |= AdtFlags::IS_FUNDAMENTAL;
2184 if Some(did) == tcx.lang_items().phantom_data() {
2185 flags |= AdtFlags::IS_PHANTOM_DATA;
2187 if Some(did) == tcx.lang_items().owned_box() {
2188 flags |= AdtFlags::IS_BOX;
2190 if Some(did) == tcx.lang_items().arc() {
2191 flags |= AdtFlags::IS_ARC;
2193 if Some(did) == tcx.lang_items().rc() {
2194 flags |= AdtFlags::IS_RC;
2205 /// Returns `true` if this is a struct.
2207 pub fn is_struct(&self) -> bool {
2208 self.flags.contains(AdtFlags::IS_STRUCT)
2211 /// Returns `true` if this is a union.
2213 pub fn is_union(&self) -> bool {
2214 self.flags.contains(AdtFlags::IS_UNION)
2217 /// Returns `true` if this is a enum.
2219 pub fn is_enum(&self) -> bool {
2220 self.flags.contains(AdtFlags::IS_ENUM)
2223 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2225 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2226 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2229 /// Returns the kind of the ADT.
2231 pub fn adt_kind(&self) -> AdtKind {
2234 } else if self.is_union() {
2241 /// Returns a description of this abstract data type.
2242 pub fn descr(&self) -> &'static str {
2243 match self.adt_kind() {
2244 AdtKind::Struct => "struct",
2245 AdtKind::Union => "union",
2246 AdtKind::Enum => "enum",
2250 /// Returns a description of a variant of this abstract data type.
2252 pub fn variant_descr(&self) -> &'static str {
2253 match self.adt_kind() {
2254 AdtKind::Struct => "struct",
2255 AdtKind::Union => "union",
2256 AdtKind::Enum => "variant",
2260 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2262 pub fn has_ctor(&self) -> bool {
2263 self.flags.contains(AdtFlags::HAS_CTOR)
2266 /// Returns `true` if this type is `#[fundamental]` for the purposes
2267 /// of coherence checking.
2269 pub fn is_fundamental(&self) -> bool {
2270 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2273 /// Returns `true` if this is `PhantomData<T>`.
2275 pub fn is_phantom_data(&self) -> bool {
2276 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2279 /// Returns `true` if this is `Arc<T>`.
2280 pub fn is_arc(&self) -> bool {
2281 self.flags.contains(AdtFlags::IS_ARC)
2284 /// Returns `true` if this is `Rc<T>`.
2285 pub fn is_rc(&self) -> bool {
2286 self.flags.contains(AdtFlags::IS_RC)
2289 /// Returns `true` if this is Box<T>.
2291 pub fn is_box(&self) -> bool {
2292 self.flags.contains(AdtFlags::IS_BOX)
2295 /// Returns `true` if this type has a destructor.
2296 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2297 self.destructor(tcx).is_some()
2300 /// Asserts this is a struct or union and returns its unique variant.
2301 pub fn non_enum_variant(&self) -> &VariantDef {
2302 assert!(self.is_struct() || self.is_union());
2303 &self.variants[VariantIdx::new(0)]
2307 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> &'tcx GenericPredicates<'tcx> {
2308 tcx.predicates_of(self.did)
2311 /// Returns an iterator over all fields contained
2314 pub fn all_fields(&self) -> impl Iterator<Item=&FieldDef> + Clone {
2315 self.variants.iter().flat_map(|v| v.fields.iter())
2318 pub fn is_payloadfree(&self) -> bool {
2319 !self.variants.is_empty() &&
2320 self.variants.iter().all(|v| v.fields.is_empty())
2323 /// Return a `VariantDef` given a variant id.
2324 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2325 self.variants.iter().find(|v| v.def_id == vid)
2326 .expect("variant_with_id: unknown variant")
2329 /// Return a `VariantDef` given a constructor id.
2330 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2331 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2332 .expect("variant_with_ctor_id: unknown variant")
2335 /// Return the index of `VariantDef` given a variant id.
2336 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2337 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2338 .expect("variant_index_with_id: unknown variant").0
2341 /// Return the index of `VariantDef` given a constructor id.
2342 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2343 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2344 .expect("variant_index_with_ctor_id: unknown variant").0
2347 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2349 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2350 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2351 Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
2352 Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) |
2353 Res::SelfCtor(..) => self.non_enum_variant(),
2354 _ => bug!("unexpected res {:?} in variant_of_res", res)
2359 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2360 let param_env = ParamEnv::empty();
2361 let repr_type = self.repr.discr_type();
2362 let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), expr_did);
2363 let instance = ty::Instance::new(expr_did, substs);
2364 let cid = GlobalId {
2368 match tcx.const_eval(param_env.and(cid)) {
2370 // FIXME: Find the right type and use it instead of `val.ty` here
2371 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2372 trace!("discriminants: {} ({:?})", b, repr_type);
2378 info!("invalid enum discriminant: {:#?}", val);
2379 crate::mir::interpret::struct_error(
2380 tcx.at(tcx.def_span(expr_did)),
2381 "constant evaluation of enum discriminant resulted in non-integer",
2386 Err(ErrorHandled::Reported) => {
2387 if !expr_did.is_local() {
2388 span_bug!(tcx.def_span(expr_did),
2389 "variant discriminant evaluation succeeded \
2390 in its crate but failed locally");
2394 Err(ErrorHandled::TooGeneric) => span_bug!(
2395 tcx.def_span(expr_did),
2396 "enum discriminant depends on generic arguments",
2402 pub fn discriminants(
2405 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2406 let repr_type = self.repr.discr_type();
2407 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2408 let mut prev_discr = None::<Discr<'tcx>>;
2409 self.variants.iter_enumerated().map(move |(i, v)| {
2410 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2411 if let VariantDiscr::Explicit(expr_did) = v.discr {
2412 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2416 prev_discr = Some(discr);
2423 pub fn variant_range(&self) -> Range<VariantIdx> {
2424 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2427 /// Computes the discriminant value used by a specific variant.
2428 /// Unlike `discriminants`, this is (amortized) constant-time,
2429 /// only doing at most one query for evaluating an explicit
2430 /// discriminant (the last one before the requested variant),
2431 /// assuming there are no constant-evaluation errors there.
2433 pub fn discriminant_for_variant(
2436 variant_index: VariantIdx,
2438 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2439 let explicit_value = val
2440 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2441 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2442 explicit_value.checked_add(tcx, offset as u128).0
2445 /// Yields a `DefId` for the discriminant and an offset to add to it
2446 /// Alternatively, if there is no explicit discriminant, returns the
2447 /// inferred discriminant directly.
2448 pub fn discriminant_def_for_variant(
2450 variant_index: VariantIdx,
2451 ) -> (Option<DefId>, u32) {
2452 let mut explicit_index = variant_index.as_u32();
2455 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2456 ty::VariantDiscr::Relative(0) => {
2460 ty::VariantDiscr::Relative(distance) => {
2461 explicit_index -= distance;
2463 ty::VariantDiscr::Explicit(did) => {
2464 expr_did = Some(did);
2469 (expr_did, variant_index.as_u32() - explicit_index)
2472 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2473 tcx.adt_destructor(self.did)
2476 /// Returns a list of types such that `Self: Sized` if and only
2477 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2479 /// Oddly enough, checking that the sized-constraint is `Sized` is
2480 /// actually more expressive than checking all members:
2481 /// the `Sized` trait is inductive, so an associated type that references
2482 /// `Self` would prevent its containing ADT from being `Sized`.
2484 /// Due to normalization being eager, this applies even if
2485 /// the associated type is behind a pointer (e.g., issue #31299).
2486 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2487 tcx.adt_sized_constraint(self.did).0
2490 fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'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<'tcx> FieldDef {
2568 pub fn ty(&self, tcx: TyCtxt<'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<'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<'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<'tcx> {
2705 Owned(Lrc<[ast::Attribute]>),
2706 Borrowed(&'tcx [ast::Attribute]),
2709 impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
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<'tcx> TyCtxt<'tcx> {
2760 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
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()`.
2767 pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
2771 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2774 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2775 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2776 f(self.hir().body_owner_def_id(body_id))
2780 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
2781 self.associated_items(id)
2782 .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
2786 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2787 self.associated_items(did).any(|item| {
2788 item.relevant_for_never()
2792 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
2793 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2794 match self.hir().get(hir_id) {
2795 Node::TraitItem(_) | Node::ImplItem(_) => true,
2799 match self.def_kind(def_id).expect("no def for def-id") {
2802 | DefKind::AssocTy => true,
2807 if is_associated_item {
2808 Some(self.associated_item(def_id))
2814 fn associated_item_from_trait_item_ref(self,
2815 parent_def_id: DefId,
2816 parent_vis: &hir::Visibility,
2817 trait_item_ref: &hir::TraitItemRef)
2819 let def_id = self.hir().local_def_id_from_hir_id(trait_item_ref.id.hir_id);
2820 let (kind, has_self) = match trait_item_ref.kind {
2821 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2822 hir::AssocItemKind::Method { has_self } => {
2823 (ty::AssocKind::Method, has_self)
2825 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2826 hir::AssocItemKind::Existential => bug!("only impls can have existentials"),
2830 ident: trait_item_ref.ident,
2832 // Visibility of trait items is inherited from their traits.
2833 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2834 defaultness: trait_item_ref.defaultness,
2836 container: TraitContainer(parent_def_id),
2837 method_has_self_argument: has_self
2841 fn associated_item_from_impl_item_ref(self,
2842 parent_def_id: DefId,
2843 impl_item_ref: &hir::ImplItemRef)
2845 let def_id = self.hir().local_def_id_from_hir_id(impl_item_ref.id.hir_id);
2846 let (kind, has_self) = match impl_item_ref.kind {
2847 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2848 hir::AssocItemKind::Method { has_self } => {
2849 (ty::AssocKind::Method, has_self)
2851 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2852 hir::AssocItemKind::Existential => (ty::AssocKind::Existential, false),
2856 ident: impl_item_ref.ident,
2858 // Visibility of trait impl items doesn't matter.
2859 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2860 defaultness: impl_item_ref.defaultness,
2862 container: ImplContainer(parent_def_id),
2863 method_has_self_argument: has_self
2867 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2868 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2871 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2872 variant.fields.iter().position(|field| {
2873 self.hygienic_eq(ident, field.ident, variant.def_id)
2877 pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
2878 // Ideally, we would use `-> impl Iterator` here, but it falls
2879 // afoul of the conservative "capture [restrictions]" we put
2880 // in place, so we use a hand-written iterator.
2882 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2883 AssocItemsIterator {
2885 def_ids: self.associated_item_def_ids(def_id),
2890 /// Returns `true` if the impls are the same polarity and the trait either
2891 /// has no items or is annotated #[marker] and prevents item overrides.
2892 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2893 -> Option<ImplOverlapKind>
2895 let is_legit = if self.features().overlapping_marker_traits {
2896 let trait1_is_empty = self.impl_trait_ref(def_id1)
2897 .map_or(false, |trait_ref| {
2898 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2900 let trait2_is_empty = self.impl_trait_ref(def_id2)
2901 .map_or(false, |trait_ref| {
2902 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2904 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2908 let is_marker_impl = |def_id: DefId| -> bool {
2909 let trait_ref = self.impl_trait_ref(def_id);
2910 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2912 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2913 && is_marker_impl(def_id1)
2914 && is_marker_impl(def_id2)
2918 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
2920 Some(ImplOverlapKind::Permitted)
2922 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2923 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2924 if self_ty1 == self_ty2 {
2925 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2927 return Some(ImplOverlapKind::Issue33140);
2929 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2930 def_id1, def_id2, self_ty1, self_ty2);
2935 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2941 /// Returns `ty::VariantDef` if `res` refers to a struct,
2942 /// or variant or their constructors, panics otherwise.
2943 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2945 Res::Def(DefKind::Variant, did) => {
2946 let enum_did = self.parent(did).unwrap();
2947 self.adt_def(enum_did).variant_with_id(did)
2949 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
2950 self.adt_def(did).non_enum_variant()
2952 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2953 let variant_did = self.parent(variant_ctor_did).unwrap();
2954 let enum_did = self.parent(variant_did).unwrap();
2955 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2957 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2958 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2959 self.adt_def(struct_did).non_enum_variant()
2961 _ => bug!("expect_variant_res used with unexpected res {:?}", res)
2965 pub fn item_name(self, id: DefId) -> Symbol {
2966 if id.index == CRATE_DEF_INDEX {
2967 self.original_crate_name(id.krate)
2969 let def_key = self.def_key(id);
2970 match def_key.disambiguated_data.data {
2971 // The name of a constructor is that of its parent.
2972 hir_map::DefPathData::Ctor =>
2973 self.item_name(DefId {
2975 index: def_key.parent.unwrap()
2977 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2978 bug!("item_name: no name for {:?}", self.def_path(id));
2984 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2985 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
2987 ty::InstanceDef::Item(did) => {
2988 self.optimized_mir(did)
2990 ty::InstanceDef::VtableShim(..) |
2991 ty::InstanceDef::Intrinsic(..) |
2992 ty::InstanceDef::FnPtrShim(..) |
2993 ty::InstanceDef::Virtual(..) |
2994 ty::InstanceDef::ClosureOnceShim { .. } |
2995 ty::InstanceDef::DropGlue(..) |
2996 ty::InstanceDef::CloneShim(..) => {
2997 self.mir_shims(instance)
3002 /// Gets the attributes of a definition.
3003 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
3004 if let Some(id) = self.hir().as_local_hir_id(did) {
3005 Attributes::Borrowed(self.hir().attrs(id))
3007 Attributes::Owned(self.item_attrs(did))
3011 /// Determines whether an item is annotated with an attribute.
3012 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
3013 attr::contains_name(&self.get_attrs(did), attr)
3016 /// Returns `true` if this is an `auto trait`.
3017 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3018 self.trait_def(trait_def_id).has_auto_impl
3021 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3022 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3025 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3026 /// If it implements no trait, returns `None`.
3027 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3028 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3031 /// If the given defid describes a method belonging to an impl, returns the
3032 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3033 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3034 let item = if def_id.krate != LOCAL_CRATE {
3035 if let Some(DefKind::Method) = self.def_kind(def_id) {
3036 Some(self.associated_item(def_id))
3041 self.opt_associated_item(def_id)
3044 item.and_then(|trait_item|
3045 match trait_item.container {
3046 TraitContainer(_) => None,
3047 ImplContainer(def_id) => Some(def_id),
3052 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3053 /// with the name of the crate containing the impl.
3054 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3055 if impl_did.is_local() {
3056 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3057 Ok(self.hir().span(hir_id))
3059 Err(self.crate_name(impl_did.krate))
3063 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3064 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3065 /// definition's parent/scope to perform comparison.
3066 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3067 // We could use `Ident::eq` here, but we deliberately don't. The name
3068 // comparison fails frequently, and we want to avoid the expensive
3069 // `modern()` calls required for the span comparison whenever possible.
3070 use_name.name == def_name.name &&
3071 use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
3072 self.expansion_that_defined(def_parent_def_id))
3075 fn expansion_that_defined(self, scope: DefId) -> Mark {
3077 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3082 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
3083 ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
3087 pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
3089 let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
3090 Some(actual_expansion) =>
3091 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3092 None => self.hir().get_module_parent(block),
3098 pub struct AssocItemsIterator<'tcx> {
3100 def_ids: &'tcx [DefId],
3104 impl Iterator for AssocItemsIterator<'_> {
3105 type Item = AssocItem;
3107 fn next(&mut self) -> Option<AssocItem> {
3108 let def_id = self.def_ids.get(self.next_index)?;
3109 self.next_index += 1;
3110 Some(self.tcx.associated_item(*def_id))
3114 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
3115 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3116 let parent_id = tcx.hir().get_parent_item(id);
3117 let parent_def_id = tcx.hir().local_def_id_from_hir_id(parent_id);
3118 let parent_item = tcx.hir().expect_item(parent_id);
3119 match parent_item.node {
3120 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3121 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3122 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3124 debug_assert_eq!(assoc_item.def_id, def_id);
3129 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3130 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3131 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3134 debug_assert_eq!(assoc_item.def_id, def_id);
3142 span_bug!(parent_item.span,
3143 "unexpected parent of trait or impl item or item not found: {:?}",
3147 #[derive(Clone, HashStable)]
3148 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3150 /// Calculates the `Sized` constraint.
3152 /// In fact, there are only a few options for the types in the constraint:
3153 /// - an obviously-unsized type
3154 /// - a type parameter or projection whose Sizedness can't be known
3155 /// - a tuple of type parameters or projections, if there are multiple
3157 /// - a Error, if a type contained itself. The representability
3158 /// check should catch this case.
3159 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
3160 let def = tcx.adt_def(def_id);
3162 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3165 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3168 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3170 AdtSizedConstraint(result)
3173 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
3174 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3175 let item = tcx.hir().expect_item(id);
3177 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3178 tcx.arena.alloc_from_iter(
3179 trait_item_refs.iter()
3180 .map(|trait_item_ref| trait_item_ref.id)
3181 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3184 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3185 tcx.arena.alloc_from_iter(
3186 impl_item_refs.iter()
3187 .map(|impl_item_ref| impl_item_ref.id)
3188 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3191 hir::ItemKind::TraitAlias(..) => &[],
3192 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3196 fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
3197 tcx.hir().span_if_local(def_id).unwrap()
3200 /// If the given `DefId` describes an item belonging to a trait,
3201 /// returns the `DefId` of the trait that the trait item belongs to;
3202 /// otherwise, returns `None`.
3203 fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3204 tcx.opt_associated_item(def_id)
3205 .and_then(|associated_item| {
3206 match associated_item.container {
3207 TraitContainer(def_id) => Some(def_id),
3208 ImplContainer(_) => None
3213 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3214 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3215 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3216 if let Node::Item(item) = tcx.hir().get(hir_id) {
3217 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3218 return exist_ty.impl_trait_fn;
3225 /// See `ParamEnv` struct definition for details.
3226 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
3227 // The param_env of an impl Trait type is its defining function's param_env
3228 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3229 return param_env(tcx, parent);
3231 // Compute the bounds on Self and the type parameters.
3233 let InstantiatedPredicates { predicates } =
3234 tcx.predicates_of(def_id).instantiate_identity(tcx);
3236 // Finally, we have to normalize the bounds in the environment, in
3237 // case they contain any associated type projections. This process
3238 // can yield errors if the put in illegal associated types, like
3239 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3240 // report these errors right here; this doesn't actually feel
3241 // right to me, because constructing the environment feels like a
3242 // kind of a "idempotent" action, but I'm not sure where would be
3243 // a better place. In practice, we construct environments for
3244 // every fn once during type checking, and we'll abort if there
3245 // are any errors at that point, so after type checking you can be
3246 // sure that this will succeed without errors anyway.
3248 let unnormalized_env = ty::ParamEnv::new(
3249 tcx.intern_predicates(&predicates),
3250 traits::Reveal::UserFacing,
3251 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3254 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3255 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
3257 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3258 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3261 fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
3262 assert_eq!(crate_num, LOCAL_CRATE);
3263 tcx.sess.local_crate_disambiguator()
3266 fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
3267 assert_eq!(crate_num, LOCAL_CRATE);
3268 tcx.crate_name.clone()
3271 fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
3272 assert_eq!(crate_num, LOCAL_CRATE);
3273 tcx.hir().crate_hash
3276 fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
3277 match instance_def {
3278 InstanceDef::Item(..) |
3279 InstanceDef::DropGlue(..) => {
3280 let mir = tcx.instance_mir(instance_def);
3281 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3283 // Estimate the size of other compiler-generated shims to be 1.
3288 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3290 /// See [`ImplOverlapKind::Issue33140`] for more details.
3291 fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
3292 debug!("issue33140_self_ty({:?})", def_id);
3294 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3295 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3298 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3300 let is_marker_like =
3301 tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
3302 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3304 // Check whether these impls would be ok for a marker trait.
3305 if !is_marker_like {
3306 debug!("issue33140_self_ty - not marker-like!");
3310 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3311 if trait_ref.substs.len() != 1 {
3312 debug!("issue33140_self_ty - impl has substs!");
3316 let predicates = tcx.predicates_of(def_id);
3317 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3318 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3322 let self_ty = trait_ref.self_ty();
3323 let self_ty_matches = match self_ty.sty {
3324 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3328 if self_ty_matches {
3329 debug!("issue33140_self_ty - MATCHES!");
3332 debug!("issue33140_self_ty - non-matching self type");
3337 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3338 context::provide(providers);
3339 erase_regions::provide(providers);
3340 layout::provide(providers);
3341 util::provide(providers);
3342 constness::provide(providers);
3343 *providers = ty::query::Providers {
3345 associated_item_def_ids,
3346 adt_sized_constraint,
3350 crate_disambiguator,
3351 original_crate_name,
3353 trait_impls_of: trait_def::trait_impls_of_provider,
3354 instance_def_size_estimate,
3360 /// A map for the local crate mapping each type to a vector of its
3361 /// inherent impls. This is not meant to be used outside of coherence;
3362 /// rather, you should request the vector for a specific type via
3363 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3364 /// (constructing this map requires touching the entire crate).
3365 #[derive(Clone, Debug, Default, HashStable)]
3366 pub struct CrateInherentImpls {
3367 pub inherent_impls: DefIdMap<Vec<DefId>>,
3370 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3371 pub struct SymbolName {
3372 // FIXME: we don't rely on interning or equality here - better have
3373 // this be a `&'tcx str`.
3374 pub name: InternedString
3377 impl_stable_hash_for!(struct self::SymbolName {
3382 pub fn new(name: &str) -> SymbolName {
3384 name: InternedString::intern(name)
3388 pub fn as_str(&self) -> LocalInternedString {
3393 impl fmt::Display for SymbolName {
3394 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3395 fmt::Display::fmt(&self.name, fmt)
3399 impl fmt::Debug for SymbolName {
3400 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3401 fmt::Display::fmt(&self.name, fmt)