1 // ignore-tidy-filelength
3 pub use self::Variance::*;
4 pub use self::AssocItemContainer::*;
5 pub use self::BorrowKind::*;
6 pub use self::IntVarValue::*;
7 pub use self::fold::TypeFoldable;
9 use crate::hir::{map as hir_map, GlobMap, TraitMap};
11 use crate::hir::def::{Res, DefKind, CtorOf, CtorKind, ExportMap};
12 use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
13 use rustc_data_structures::svh::Svh;
14 use rustc_macros::HashStable;
15 use crate::ich::Fingerprint;
16 use crate::ich::StableHashingContext;
17 use crate::infer::canonical::Canonical;
18 use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
19 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
21 use crate::mir::interpret::{GlobalId, ErrorHandled};
22 use crate::mir::GeneratorLayout;
23 use crate::session::CrateDisambiguator;
24 use crate::traits::{self, Reveal};
26 use crate::ty::layout::VariantIdx;
27 use crate::ty::subst::{Subst, InternalSubsts, SubstsRef};
28 use crate::ty::util::{IntTypeExt, Discr};
29 use crate::ty::walk::TypeWalker;
30 use crate::util::captures::Captures;
31 use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap};
32 use arena::SyncDroplessArena;
33 use crate::session::DataTypeKind;
35 use rustc_serialize::{self, Encodable, Encoder};
36 use rustc_target::abi::Align;
37 use std::cell::RefCell;
38 use std::cmp::{self, Ordering};
40 use std::hash::{Hash, Hasher};
42 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
46 use syntax::ast::{self, Name, Ident, NodeId};
48 use syntax::ext::hygiene::ExpnId;
49 use syntax::symbol::{kw, sym, Symbol, InternedString};
53 use rustc_data_structures::fx::FxIndexMap;
54 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
55 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
60 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
61 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
62 pub use self::sty::{InferTy, ParamTy, ParamConst, InferConst, ProjectionTy, ExistentialPredicate};
63 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
64 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
65 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
66 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
67 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
68 pub use self::sty::RegionKind;
69 pub use self::sty::{TyVid, IntVid, FloatVid, ConstVid, RegionVid};
70 pub use self::sty::BoundRegion::*;
71 pub use self::sty::InferTy::*;
72 pub use self::sty::RegionKind::*;
73 pub use self::sty::TyKind::*;
75 pub use self::binding::BindingMode;
76 pub use self::binding::BindingMode::*;
78 pub use self::context::{TyCtxt, FreeRegionInfo, AllArenas, tls, keep_local};
79 pub use self::context::{Lift, TypeckTables, CtxtInterners, GlobalCtxt};
80 pub use self::context::{
81 UserTypeAnnotationIndex, UserType, CanonicalUserType,
82 CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
85 pub use self::instance::{Instance, InstanceDef};
87 pub use self::trait_def::TraitDef;
89 pub use self::query::queries;
102 pub mod inhabitedness;
118 mod structural_impls;
124 pub struct Resolutions {
125 pub trait_map: TraitMap,
126 pub maybe_unused_trait_imports: NodeSet,
127 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
128 pub export_map: ExportMap<NodeId>,
129 pub glob_map: GlobMap,
130 /// Extern prelude entries. The value is `true` if the entry was introduced
131 /// via `extern crate` item and not `--extern` option or compiler built-in.
132 pub extern_prelude: FxHashMap<Name, bool>,
135 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
136 pub enum AssocItemContainer {
137 TraitContainer(DefId),
138 ImplContainer(DefId),
141 impl AssocItemContainer {
142 /// Asserts that this is the `DefId` of an associated item declared
143 /// in a trait, and returns the trait `DefId`.
144 pub fn assert_trait(&self) -> DefId {
146 TraitContainer(id) => id,
147 _ => bug!("associated item has wrong container type: {:?}", self)
151 pub fn id(&self) -> DefId {
153 TraitContainer(id) => id,
154 ImplContainer(id) => id,
159 /// The "header" of an impl is everything outside the body: a Self type, a trait
160 /// ref (in the case of a trait impl), and a set of predicates (from the
161 /// bounds / where-clauses).
162 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
163 pub struct ImplHeader<'tcx> {
164 pub impl_def_id: DefId,
165 pub self_ty: Ty<'tcx>,
166 pub trait_ref: Option<TraitRef<'tcx>>,
167 pub predicates: Vec<Predicate<'tcx>>,
170 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
171 pub enum ImplPolarity {
172 /// `impl Trait for Type`
174 /// `impl !Trait for Type`
176 /// `#[rustc_reservation_impl] impl Trait for Type`
178 /// This is a "stability hack", not a real Rust feature.
179 /// See #64631 for details.
183 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
184 pub struct AssocItem {
186 #[stable_hasher(project(name))]
190 pub defaultness: hir::Defaultness,
191 pub container: AssocItemContainer,
193 /// Whether this is a method with an explicit self
194 /// as its first argument, allowing method calls.
195 pub method_has_self_argument: bool,
198 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable, HashStable)]
207 pub fn def_kind(&self) -> DefKind {
209 AssocKind::Const => DefKind::AssocConst,
210 AssocKind::Method => DefKind::Method,
211 AssocKind::Type => DefKind::AssocTy,
212 AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
216 /// Tests whether the associated item admits a non-trivial implementation
218 pub fn relevant_for_never(&self) -> bool {
220 AssocKind::OpaqueTy |
222 AssocKind::Type => true,
223 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
224 AssocKind::Method => !self.method_has_self_argument,
228 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
230 ty::AssocKind::Method => {
231 // We skip the binder here because the binder would deanonymize all
232 // late-bound regions, and we don't want method signatures to show up
233 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
234 // regions just fine, showing `fn(&MyType)`.
235 tcx.fn_sig(self.def_id).skip_binder().to_string()
237 ty::AssocKind::Type => format!("type {};", self.ident),
238 // FIXME(type_alias_impl_trait): we should print bounds here too.
239 ty::AssocKind::OpaqueTy => format!("type {};", self.ident),
240 ty::AssocKind::Const => {
241 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
247 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
248 pub enum Visibility {
249 /// Visible everywhere (including in other crates).
251 /// Visible only in the given crate-local module.
253 /// Not visible anywhere in the local crate. This is the visibility of private external items.
257 pub trait DefIdTree: Copy {
258 fn parent(self, id: DefId) -> Option<DefId>;
260 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
261 if descendant.krate != ancestor.krate {
265 while descendant != ancestor {
266 match self.parent(descendant) {
267 Some(parent) => descendant = parent,
268 None => return false,
275 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
276 fn parent(self, id: DefId) -> Option<DefId> {
277 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
282 pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
283 match visibility.node {
284 hir::VisibilityKind::Public => Visibility::Public,
285 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
286 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
287 // If there is no resolution, `resolve` will have already reported an error, so
288 // assume that the visibility is public to avoid reporting more privacy errors.
289 Res::Err => Visibility::Public,
290 def => Visibility::Restricted(def.def_id()),
292 hir::VisibilityKind::Inherited => {
293 Visibility::Restricted(tcx.hir().get_module_parent(id))
298 /// Returns `true` if an item with this visibility is accessible from the given block.
299 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
300 let restriction = match self {
301 // Public items are visible everywhere.
302 Visibility::Public => return true,
303 // Private items from other crates are visible nowhere.
304 Visibility::Invisible => return false,
305 // Restricted items are visible in an arbitrary local module.
306 Visibility::Restricted(other) if other.krate != module.krate => return false,
307 Visibility::Restricted(module) => module,
310 tree.is_descendant_of(module, restriction)
313 /// Returns `true` if this visibility is at least as accessible as the given visibility
314 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
315 let vis_restriction = match vis {
316 Visibility::Public => return self == Visibility::Public,
317 Visibility::Invisible => return true,
318 Visibility::Restricted(module) => module,
321 self.is_accessible_from(vis_restriction, tree)
324 // Returns `true` if this item is visible anywhere in the local crate.
325 pub fn is_visible_locally(self) -> bool {
327 Visibility::Public => true,
328 Visibility::Restricted(def_id) => def_id.is_local(),
329 Visibility::Invisible => false,
334 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash, HashStable)]
336 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
337 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
338 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
339 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
342 /// The crate variances map is computed during typeck and contains the
343 /// variance of every item in the local crate. You should not use it
344 /// directly, because to do so will make your pass dependent on the
345 /// HIR of every item in the local crate. Instead, use
346 /// `tcx.variances_of()` to get the variance for a *particular*
348 #[derive(HashStable)]
349 pub struct CrateVariancesMap<'tcx> {
350 /// For each item with generics, maps to a vector of the variance
351 /// of its generics. If an item has no generics, it will have no
353 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
357 /// `a.xform(b)` combines the variance of a context with the
358 /// variance of a type with the following meaning. If we are in a
359 /// context with variance `a`, and we encounter a type argument in
360 /// a position with variance `b`, then `a.xform(b)` is the new
361 /// variance with which the argument appears.
367 /// Here, the "ambient" variance starts as covariant. `*mut T` is
368 /// invariant with respect to `T`, so the variance in which the
369 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
370 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
371 /// respect to its type argument `T`, and hence the variance of
372 /// the `i32` here is `Invariant.xform(Covariant)`, which results
373 /// (again) in `Invariant`.
377 /// fn(*const Vec<i32>, *mut Vec<i32)
379 /// The ambient variance is covariant. A `fn` type is
380 /// contravariant with respect to its parameters, so the variance
381 /// within which both pointer types appear is
382 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
383 /// T` is covariant with respect to `T`, so the variance within
384 /// which the first `Vec<i32>` appears is
385 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
386 /// is true for its `i32` argument. In the `*mut T` case, the
387 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
388 /// and hence the outermost type is `Invariant` with respect to
389 /// `Vec<i32>` (and its `i32` argument).
391 /// Source: Figure 1 of "Taming the Wildcards:
392 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
393 pub fn xform(self, v: ty::Variance) -> ty::Variance {
395 // Figure 1, column 1.
396 (ty::Covariant, ty::Covariant) => ty::Covariant,
397 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
398 (ty::Covariant, ty::Invariant) => ty::Invariant,
399 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
401 // Figure 1, column 2.
402 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
403 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
404 (ty::Contravariant, ty::Invariant) => ty::Invariant,
405 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
407 // Figure 1, column 3.
408 (ty::Invariant, _) => ty::Invariant,
410 // Figure 1, column 4.
411 (ty::Bivariant, _) => ty::Bivariant,
416 // Contains information needed to resolve types and (in the future) look up
417 // the types of AST nodes.
418 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
419 pub struct CReaderCacheKey {
424 // Flags that we track on types. These flags are propagated upwards
425 // through the type during type construction, so that we can quickly
426 // check whether the type has various kinds of types in it without
427 // recursing over the type itself.
429 pub struct TypeFlags: u32 {
430 const HAS_PARAMS = 1 << 0;
431 const HAS_TY_INFER = 1 << 1;
432 const HAS_RE_INFER = 1 << 2;
433 const HAS_RE_PLACEHOLDER = 1 << 3;
435 /// Does this have any `ReEarlyBound` regions? Used to
436 /// determine whether substitition is required, since those
437 /// represent regions that are bound in a `ty::Generics` and
438 /// hence may be substituted.
439 const HAS_RE_EARLY_BOUND = 1 << 4;
441 /// Does this have any region that "appears free" in the type?
442 /// Basically anything but `ReLateBound` and `ReErased`.
443 const HAS_FREE_REGIONS = 1 << 5;
445 /// Is an error type reachable?
446 const HAS_TY_ERR = 1 << 6;
447 const HAS_PROJECTION = 1 << 7;
449 // FIXME: Rename this to the actual property since it's used for generators too
450 const HAS_TY_CLOSURE = 1 << 8;
452 /// `true` if there are "names" of types and regions and so forth
453 /// that are local to a particular fn
454 const HAS_FREE_LOCAL_NAMES = 1 << 9;
456 /// Present if the type belongs in a local type context.
457 /// Only set for Infer other than Fresh.
458 const KEEP_IN_LOCAL_TCX = 1 << 10;
460 /// Does this have any `ReLateBound` regions? Used to check
461 /// if a global bound is safe to evaluate.
462 const HAS_RE_LATE_BOUND = 1 << 11;
464 const HAS_TY_PLACEHOLDER = 1 << 12;
466 const HAS_CT_INFER = 1 << 13;
467 const HAS_CT_PLACEHOLDER = 1 << 14;
469 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
470 TypeFlags::HAS_RE_EARLY_BOUND.bits;
472 /// Flags representing the nominal content of a type,
473 /// computed by FlagsComputation. If you add a new nominal
474 /// flag, it should be added here too.
475 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
476 TypeFlags::HAS_TY_INFER.bits |
477 TypeFlags::HAS_RE_INFER.bits |
478 TypeFlags::HAS_RE_PLACEHOLDER.bits |
479 TypeFlags::HAS_RE_EARLY_BOUND.bits |
480 TypeFlags::HAS_FREE_REGIONS.bits |
481 TypeFlags::HAS_TY_ERR.bits |
482 TypeFlags::HAS_PROJECTION.bits |
483 TypeFlags::HAS_TY_CLOSURE.bits |
484 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
485 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
486 TypeFlags::HAS_RE_LATE_BOUND.bits |
487 TypeFlags::HAS_TY_PLACEHOLDER.bits |
488 TypeFlags::HAS_CT_INFER.bits |
489 TypeFlags::HAS_CT_PLACEHOLDER.bits;
493 #[allow(rustc::usage_of_ty_tykind)]
494 pub struct TyS<'tcx> {
495 pub kind: TyKind<'tcx>,
496 pub flags: TypeFlags,
498 /// This is a kind of confusing thing: it stores the smallest
501 /// (a) the binder itself captures nothing but
502 /// (b) all the late-bound things within the type are captured
503 /// by some sub-binder.
505 /// So, for a type without any late-bound things, like `u32`, this
506 /// will be *innermost*, because that is the innermost binder that
507 /// captures nothing. But for a type `&'D u32`, where `'D` is a
508 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
509 /// -- the binder itself does not capture `D`, but `D` is captured
510 /// by an inner binder.
512 /// We call this concept an "exclusive" binder `D` because all
513 /// De Bruijn indices within the type are contained within `0..D`
515 outer_exclusive_binder: ty::DebruijnIndex,
518 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
519 #[cfg(target_arch = "x86_64")]
520 static_assert_size!(TyS<'_>, 32);
522 impl<'tcx> Ord for TyS<'tcx> {
523 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
524 self.kind.cmp(&other.kind)
528 impl<'tcx> PartialOrd for TyS<'tcx> {
529 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
530 Some(self.kind.cmp(&other.kind))
534 impl<'tcx> PartialEq for TyS<'tcx> {
536 fn eq(&self, other: &TyS<'tcx>) -> bool {
540 impl<'tcx> Eq for TyS<'tcx> {}
542 impl<'tcx> Hash for TyS<'tcx> {
543 fn hash<H: Hasher>(&self, s: &mut H) {
544 (self as *const TyS<'_>).hash(s)
548 impl<'tcx> TyS<'tcx> {
549 pub fn is_primitive_ty(&self) -> bool {
556 Infer(InferTy::IntVar(_)) |
557 Infer(InferTy::FloatVar(_)) |
558 Infer(InferTy::FreshIntTy(_)) |
559 Infer(InferTy::FreshFloatTy(_)) => true,
560 Ref(_, x, _) => x.is_primitive_ty(),
565 pub fn is_suggestable(&self) -> bool {
573 Projection(..) => false,
579 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
580 fn hash_stable<W: StableHasherResult>(&self,
581 hcx: &mut StableHashingContext<'a>,
582 hasher: &mut StableHasher<W>) {
586 // The other fields just provide fast access to information that is
587 // also contained in `kind`, so no need to hash them.
590 outer_exclusive_binder: _,
593 kind.hash_stable(hcx, hasher);
597 #[rustc_diagnostic_item = "Ty"]
598 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
600 impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {}
601 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {}
603 pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
606 /// A dummy type used to force `List` to by unsized without requiring fat pointers.
607 type OpaqueListContents;
610 /// A wrapper for slices with the additional invariant
611 /// that the slice is interned and no other slice with
612 /// the same contents can exist in the same context.
613 /// This means we can use pointer for both
614 /// equality comparisons and hashing.
615 /// Note: `Slice` was already taken by the `Ty`.
620 opaque: OpaqueListContents,
623 unsafe impl<T: Sync> Sync for List<T> {}
625 impl<T: Copy> List<T> {
627 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
628 assert!(!mem::needs_drop::<T>());
629 assert!(mem::size_of::<T>() != 0);
630 assert!(slice.len() != 0);
632 // Align up the size of the len (usize) field
633 let align = mem::align_of::<T>();
634 let align_mask = align - 1;
635 let offset = mem::size_of::<usize>();
636 let offset = (offset + align_mask) & !align_mask;
638 let size = offset + slice.len() * mem::size_of::<T>();
640 let mem = arena.alloc_raw(
642 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
644 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
646 result.len = slice.len();
648 // Write the elements
649 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
650 arena_slice.copy_from_slice(slice);
657 impl<T: fmt::Debug> fmt::Debug for List<T> {
658 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
663 impl<T: Encodable> Encodable for List<T> {
665 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
670 impl<T> Ord for List<T> where T: Ord {
671 fn cmp(&self, other: &List<T>) -> Ordering {
672 if self == other { Ordering::Equal } else {
673 <[T] as Ord>::cmp(&**self, &**other)
678 impl<T> PartialOrd for List<T> where T: PartialOrd {
679 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
680 if self == other { Some(Ordering::Equal) } else {
681 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
686 impl<T: PartialEq> PartialEq for List<T> {
688 fn eq(&self, other: &List<T>) -> bool {
692 impl<T: Eq> Eq for List<T> {}
694 impl<T> Hash for List<T> {
696 fn hash<H: Hasher>(&self, s: &mut H) {
697 (self as *const List<T>).hash(s)
701 impl<T> Deref for List<T> {
704 fn deref(&self) -> &[T] {
706 slice::from_raw_parts(self.data.as_ptr(), self.len)
711 impl<'a, T> IntoIterator for &'a List<T> {
713 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
715 fn into_iter(self) -> Self::IntoIter {
720 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
724 pub fn empty<'a>() -> &'a List<T> {
725 #[repr(align(64), C)]
726 struct EmptySlice([u8; 64]);
727 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
728 assert!(mem::align_of::<T>() <= 64);
730 &*(&EMPTY_SLICE as *const _ as *const List<T>)
735 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
736 pub struct UpvarPath {
737 pub hir_id: hir::HirId,
740 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
741 /// the original var ID (that is, the root variable that is referenced
742 /// by the upvar) and the ID of the closure expression.
743 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
745 pub var_path: UpvarPath,
746 pub closure_expr_id: LocalDefId,
749 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
750 pub enum BorrowKind {
751 /// Data must be immutable and is aliasable.
754 /// Data must be immutable but not aliasable. This kind of borrow
755 /// cannot currently be expressed by the user and is used only in
756 /// implicit closure bindings. It is needed when the closure
757 /// is borrowing or mutating a mutable referent, e.g.:
759 /// let x: &mut isize = ...;
760 /// let y = || *x += 5;
762 /// If we were to try to translate this closure into a more explicit
763 /// form, we'd encounter an error with the code as written:
765 /// struct Env { x: & &mut isize }
766 /// let x: &mut isize = ...;
767 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
768 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
770 /// This is then illegal because you cannot mutate a `&mut` found
771 /// in an aliasable location. To solve, you'd have to translate with
772 /// an `&mut` borrow:
774 /// struct Env { x: & &mut isize }
775 /// let x: &mut isize = ...;
776 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
777 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
779 /// Now the assignment to `**env.x` is legal, but creating a
780 /// mutable pointer to `x` is not because `x` is not mutable. We
781 /// could fix this by declaring `x` as `let mut x`. This is ok in
782 /// user code, if awkward, but extra weird for closures, since the
783 /// borrow is hidden.
785 /// So we introduce a "unique imm" borrow -- the referent is
786 /// immutable, but not aliasable. This solves the problem. For
787 /// simplicity, we don't give users the way to express this
788 /// borrow, it's just used when translating closures.
791 /// Data is mutable and not aliasable.
795 /// Information describing the capture of an upvar. This is computed
796 /// during `typeck`, specifically by `regionck`.
797 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
798 pub enum UpvarCapture<'tcx> {
799 /// Upvar is captured by value. This is always true when the
800 /// closure is labeled `move`, but can also be true in other cases
801 /// depending on inference.
804 /// Upvar is captured by reference.
805 ByRef(UpvarBorrow<'tcx>),
808 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
809 pub struct UpvarBorrow<'tcx> {
810 /// The kind of borrow: by-ref upvars have access to shared
811 /// immutable borrows, which are not part of the normal language
813 pub kind: BorrowKind,
815 /// Region of the resulting reference.
816 pub region: ty::Region<'tcx>,
819 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
820 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
822 #[derive(Copy, Clone)]
823 pub struct ClosureUpvar<'tcx> {
829 #[derive(Clone, Copy, PartialEq, Eq)]
830 pub enum IntVarValue {
832 UintType(ast::UintTy),
835 #[derive(Clone, Copy, PartialEq, Eq)]
836 pub struct FloatVarValue(pub ast::FloatTy);
838 impl ty::EarlyBoundRegion {
839 pub fn to_bound_region(&self) -> ty::BoundRegion {
840 ty::BoundRegion::BrNamed(self.def_id, self.name)
843 /// Does this early bound region have a name? Early bound regions normally
844 /// always have names except when using anonymous lifetimes (`'_`).
845 pub fn has_name(&self) -> bool {
846 self.name != kw::UnderscoreLifetime.as_interned_str()
850 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
851 pub enum GenericParamDefKind {
855 object_lifetime_default: ObjectLifetimeDefault,
856 synthetic: Option<hir::SyntheticTyParamKind>,
861 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
862 pub struct GenericParamDef {
863 pub name: InternedString,
867 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
868 /// on generic parameter `'a`/`T`, asserts data behind the parameter
869 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
870 pub pure_wrt_drop: bool,
872 pub kind: GenericParamDefKind,
875 impl GenericParamDef {
876 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
877 if let GenericParamDefKind::Lifetime = self.kind {
878 ty::EarlyBoundRegion {
884 bug!("cannot convert a non-lifetime parameter def to an early bound region")
888 pub fn to_bound_region(&self) -> ty::BoundRegion {
889 if let GenericParamDefKind::Lifetime = self.kind {
890 self.to_early_bound_region_data().to_bound_region()
892 bug!("cannot convert a non-lifetime parameter def to an early bound region")
898 pub struct GenericParamCount {
899 pub lifetimes: usize,
904 /// Information about the formal type/lifetime parameters associated
905 /// with an item or method. Analogous to `hir::Generics`.
907 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
908 /// `Self` (optionally), `Lifetime` params..., `Type` params...
909 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
910 pub struct Generics {
911 pub parent: Option<DefId>,
912 pub parent_count: usize,
913 pub params: Vec<GenericParamDef>,
915 /// Reverse map to the `index` field of each `GenericParamDef`.
916 #[stable_hasher(ignore)]
917 pub param_def_id_to_index: FxHashMap<DefId, u32>,
920 pub has_late_bound_regions: Option<Span>,
923 impl<'tcx> Generics {
924 pub fn count(&self) -> usize {
925 self.parent_count + self.params.len()
928 pub fn own_counts(&self) -> GenericParamCount {
929 // We could cache this as a property of `GenericParamCount`, but
930 // the aim is to refactor this away entirely eventually and the
931 // presence of this method will be a constant reminder.
932 let mut own_counts: GenericParamCount = Default::default();
934 for param in &self.params {
936 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
937 GenericParamDefKind::Type { .. } => own_counts.types += 1,
938 GenericParamDefKind::Const => own_counts.consts += 1,
945 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
946 if self.own_requires_monomorphization() {
950 if let Some(parent_def_id) = self.parent {
951 let parent = tcx.generics_of(parent_def_id);
952 parent.requires_monomorphization(tcx)
958 pub fn own_requires_monomorphization(&self) -> bool {
959 for param in &self.params {
961 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
962 GenericParamDefKind::Lifetime => {}
970 param: &EarlyBoundRegion,
972 ) -> &'tcx GenericParamDef {
973 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
974 let param = &self.params[index as usize];
976 GenericParamDefKind::Lifetime => param,
977 _ => bug!("expected lifetime parameter, but found another generic parameter")
980 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
981 .region_param(param, tcx)
985 /// Returns the `GenericParamDef` associated with this `ParamTy`.
986 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
987 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
988 let param = &self.params[index as usize];
990 GenericParamDefKind::Type { .. } => param,
991 _ => bug!("expected type parameter, but found another generic parameter")
994 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
995 .type_param(param, tcx)
999 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
1000 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
1001 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
1002 let param = &self.params[index as usize];
1004 GenericParamDefKind::Const => param,
1005 _ => bug!("expected const parameter, but found another generic parameter")
1008 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1009 .const_param(param, tcx)
1014 /// Bounds on generics.
1015 #[derive(Clone, Default, Debug, HashStable)]
1016 pub struct GenericPredicates<'tcx> {
1017 pub parent: Option<DefId>,
1018 pub predicates: Vec<(Predicate<'tcx>, Span)>,
1021 impl<'tcx> rustc_serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
1022 impl<'tcx> rustc_serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
1024 impl<'tcx> GenericPredicates<'tcx> {
1028 substs: SubstsRef<'tcx>,
1029 ) -> InstantiatedPredicates<'tcx> {
1030 let mut instantiated = InstantiatedPredicates::empty();
1031 self.instantiate_into(tcx, &mut instantiated, substs);
1035 pub fn instantiate_own(
1038 substs: SubstsRef<'tcx>,
1039 ) -> InstantiatedPredicates<'tcx> {
1040 InstantiatedPredicates {
1041 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1045 fn instantiate_into(
1048 instantiated: &mut InstantiatedPredicates<'tcx>,
1049 substs: SubstsRef<'tcx>,
1051 if let Some(def_id) = self.parent {
1052 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1054 instantiated.predicates.extend(
1055 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1059 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
1060 let mut instantiated = InstantiatedPredicates::empty();
1061 self.instantiate_identity_into(tcx, &mut instantiated);
1065 fn instantiate_identity_into(
1068 instantiated: &mut InstantiatedPredicates<'tcx>,
1070 if let Some(def_id) = self.parent {
1071 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1073 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1076 pub fn instantiate_supertrait(
1079 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1080 ) -> InstantiatedPredicates<'tcx> {
1081 assert_eq!(self.parent, None);
1082 InstantiatedPredicates {
1083 predicates: self.predicates.iter().map(|(pred, _)| {
1084 pred.subst_supertrait(tcx, poly_trait_ref)
1090 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1091 pub enum Predicate<'tcx> {
1092 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1093 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1094 /// would be the type parameters.
1095 Trait(PolyTraitPredicate<'tcx>),
1098 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1101 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1103 /// `where <T as TraitRef>::Name == X`, approximately.
1104 /// See the `ProjectionPredicate` struct for details.
1105 Projection(PolyProjectionPredicate<'tcx>),
1107 /// No syntax: `T` well-formed.
1108 WellFormed(Ty<'tcx>),
1110 /// Trait must be object-safe.
1113 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1114 /// for some substitutions `...` and `T` being a closure type.
1115 /// Satisfied (or refuted) once we know the closure's kind.
1116 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1119 Subtype(PolySubtypePredicate<'tcx>),
1121 /// Constant initializer must evaluate successfully.
1122 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1125 /// The crate outlives map is computed during typeck and contains the
1126 /// outlives of every item in the local crate. You should not use it
1127 /// directly, because to do so will make your pass dependent on the
1128 /// HIR of every item in the local crate. Instead, use
1129 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1131 #[derive(HashStable)]
1132 pub struct CratePredicatesMap<'tcx> {
1133 /// For each struct with outlive bounds, maps to a vector of the
1134 /// predicate of its outlive bounds. If an item has no outlives
1135 /// bounds, it will have no entry.
1136 pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
1139 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1140 fn as_ref(&self) -> &Predicate<'tcx> {
1145 impl<'tcx> Predicate<'tcx> {
1146 /// Performs a substitution suitable for going from a
1147 /// poly-trait-ref to supertraits that must hold if that
1148 /// poly-trait-ref holds. This is slightly different from a normal
1149 /// substitution in terms of what happens with bound regions. See
1150 /// lengthy comment below for details.
1151 pub fn subst_supertrait(
1154 trait_ref: &ty::PolyTraitRef<'tcx>,
1155 ) -> ty::Predicate<'tcx> {
1156 // The interaction between HRTB and supertraits is not entirely
1157 // obvious. Let me walk you (and myself) through an example.
1159 // Let's start with an easy case. Consider two traits:
1161 // trait Foo<'a>: Bar<'a,'a> { }
1162 // trait Bar<'b,'c> { }
1164 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1165 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1166 // knew that `Foo<'x>` (for any 'x) then we also know that
1167 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1168 // normal substitution.
1170 // In terms of why this is sound, the idea is that whenever there
1171 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1172 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1173 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1176 // Another example to be careful of is this:
1178 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1179 // trait Bar1<'b,'c> { }
1181 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1182 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1183 // reason is similar to the previous example: any impl of
1184 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1185 // basically we would want to collapse the bound lifetimes from
1186 // the input (`trait_ref`) and the supertraits.
1188 // To achieve this in practice is fairly straightforward. Let's
1189 // consider the more complicated scenario:
1191 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1192 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1193 // where both `'x` and `'b` would have a DB index of 1.
1194 // The substitution from the input trait-ref is therefore going to be
1195 // `'a => 'x` (where `'x` has a DB index of 1).
1196 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1197 // early-bound parameter and `'b' is a late-bound parameter with a
1199 // - If we replace `'a` with `'x` from the input, it too will have
1200 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1201 // just as we wanted.
1203 // There is only one catch. If we just apply the substitution `'a
1204 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1205 // adjust the DB index because we substituting into a binder (it
1206 // tries to be so smart...) resulting in `for<'x> for<'b>
1207 // Bar1<'x,'b>` (we have no syntax for this, so use your
1208 // imagination). Basically the 'x will have DB index of 2 and 'b
1209 // will have DB index of 1. Not quite what we want. So we apply
1210 // the substitution to the *contents* of the trait reference,
1211 // rather than the trait reference itself (put another way, the
1212 // substitution code expects equal binding levels in the values
1213 // from the substitution and the value being substituted into, and
1214 // this trick achieves that).
1216 let substs = &trait_ref.skip_binder().substs;
1218 Predicate::Trait(ref binder) =>
1219 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1220 Predicate::Subtype(ref binder) =>
1221 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1222 Predicate::RegionOutlives(ref binder) =>
1223 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1224 Predicate::TypeOutlives(ref binder) =>
1225 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1226 Predicate::Projection(ref binder) =>
1227 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1228 Predicate::WellFormed(data) =>
1229 Predicate::WellFormed(data.subst(tcx, substs)),
1230 Predicate::ObjectSafe(trait_def_id) =>
1231 Predicate::ObjectSafe(trait_def_id),
1232 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1233 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1234 Predicate::ConstEvaluatable(def_id, const_substs) =>
1235 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1240 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1241 pub struct TraitPredicate<'tcx> {
1242 pub trait_ref: TraitRef<'tcx>
1245 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1247 impl<'tcx> TraitPredicate<'tcx> {
1248 pub fn def_id(&self) -> DefId {
1249 self.trait_ref.def_id
1252 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
1253 self.trait_ref.input_types()
1256 pub fn self_ty(&self) -> Ty<'tcx> {
1257 self.trait_ref.self_ty()
1261 impl<'tcx> PolyTraitPredicate<'tcx> {
1262 pub fn def_id(&self) -> DefId {
1263 // Ok to skip binder since trait `DefId` does not care about regions.
1264 self.skip_binder().def_id()
1268 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1269 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1270 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1271 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1272 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1273 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1274 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1275 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1277 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1278 pub struct SubtypePredicate<'tcx> {
1279 pub a_is_expected: bool,
1283 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1285 /// This kind of predicate has no *direct* correspondent in the
1286 /// syntax, but it roughly corresponds to the syntactic forms:
1288 /// 1. `T: TraitRef<..., Item = Type>`
1289 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1291 /// In particular, form #1 is "desugared" to the combination of a
1292 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1293 /// predicates. Form #2 is a broader form in that it also permits
1294 /// equality between arbitrary types. Processing an instance of
1295 /// Form #2 eventually yields one of these `ProjectionPredicate`
1296 /// instances to normalize the LHS.
1297 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1298 pub struct ProjectionPredicate<'tcx> {
1299 pub projection_ty: ProjectionTy<'tcx>,
1303 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1305 impl<'tcx> PolyProjectionPredicate<'tcx> {
1306 /// Returns the `DefId` of the associated item being projected.
1307 pub fn item_def_id(&self) -> DefId {
1308 self.skip_binder().projection_ty.item_def_id
1312 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_>) -> PolyTraitRef<'tcx> {
1313 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1314 // `self.0.trait_ref` is permitted to have escaping regions.
1315 // This is because here `self` has a `Binder` and so does our
1316 // return value, so we are preserving the number of binding
1318 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1321 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1322 self.map_bound(|predicate| predicate.ty)
1325 /// The `DefId` of the `TraitItem` for the associated type.
1327 /// Note that this is not the `DefId` of the `TraitRef` containing this
1328 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1329 pub fn projection_def_id(&self) -> DefId {
1330 // Ok to skip binder since trait `DefId` does not care about regions.
1331 self.skip_binder().projection_ty.item_def_id
1335 pub trait ToPolyTraitRef<'tcx> {
1336 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1339 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1340 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1341 ty::Binder::dummy(self.clone())
1345 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1346 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1347 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1351 pub trait ToPredicate<'tcx> {
1352 fn to_predicate(&self) -> Predicate<'tcx>;
1355 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1356 fn to_predicate(&self) -> Predicate<'tcx> {
1357 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1358 trait_ref: self.clone()
1363 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1364 fn to_predicate(&self) -> Predicate<'tcx> {
1365 ty::Predicate::Trait(self.to_poly_trait_predicate())
1369 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1370 fn to_predicate(&self) -> Predicate<'tcx> {
1371 Predicate::RegionOutlives(self.clone())
1375 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1376 fn to_predicate(&self) -> Predicate<'tcx> {
1377 Predicate::TypeOutlives(self.clone())
1381 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1382 fn to_predicate(&self) -> Predicate<'tcx> {
1383 Predicate::Projection(self.clone())
1387 // A custom iterator used by `Predicate::walk_tys`.
1388 enum WalkTysIter<'tcx, I, J, K>
1389 where I: Iterator<Item = Ty<'tcx>>,
1390 J: Iterator<Item = Ty<'tcx>>,
1391 K: Iterator<Item = Ty<'tcx>>
1395 Two(Ty<'tcx>, Ty<'tcx>),
1401 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1402 where I: Iterator<Item = Ty<'tcx>>,
1403 J: Iterator<Item = Ty<'tcx>>,
1404 K: Iterator<Item = Ty<'tcx>>
1406 type Item = Ty<'tcx>;
1408 fn next(&mut self) -> Option<Ty<'tcx>> {
1410 WalkTysIter::None => None,
1411 WalkTysIter::One(item) => {
1412 *self = WalkTysIter::None;
1415 WalkTysIter::Two(item1, item2) => {
1416 *self = WalkTysIter::One(item2);
1419 WalkTysIter::Types(ref mut iter) => {
1422 WalkTysIter::InputTypes(ref mut iter) => {
1425 WalkTysIter::ProjectionTypes(ref mut iter) => {
1432 impl<'tcx> Predicate<'tcx> {
1433 /// Iterates over the types in this predicate. Note that in all
1434 /// cases this is skipping over a binder, so late-bound regions
1435 /// with depth 0 are bound by the predicate.
1436 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1438 ty::Predicate::Trait(ref data) => {
1439 WalkTysIter::InputTypes(data.skip_binder().input_types())
1441 ty::Predicate::Subtype(binder) => {
1442 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1443 WalkTysIter::Two(a, b)
1445 ty::Predicate::TypeOutlives(binder) => {
1446 WalkTysIter::One(binder.skip_binder().0)
1448 ty::Predicate::RegionOutlives(..) => {
1451 ty::Predicate::Projection(ref data) => {
1452 let inner = data.skip_binder();
1453 WalkTysIter::ProjectionTypes(
1454 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1456 ty::Predicate::WellFormed(data) => {
1457 WalkTysIter::One(data)
1459 ty::Predicate::ObjectSafe(_trait_def_id) => {
1462 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1463 WalkTysIter::Types(closure_substs.substs.types())
1465 ty::Predicate::ConstEvaluatable(_, substs) => {
1466 WalkTysIter::Types(substs.types())
1471 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1473 Predicate::Trait(ref t) => {
1474 Some(t.to_poly_trait_ref())
1476 Predicate::Projection(..) |
1477 Predicate::Subtype(..) |
1478 Predicate::RegionOutlives(..) |
1479 Predicate::WellFormed(..) |
1480 Predicate::ObjectSafe(..) |
1481 Predicate::ClosureKind(..) |
1482 Predicate::TypeOutlives(..) |
1483 Predicate::ConstEvaluatable(..) => {
1489 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1491 Predicate::TypeOutlives(data) => {
1494 Predicate::Trait(..) |
1495 Predicate::Projection(..) |
1496 Predicate::Subtype(..) |
1497 Predicate::RegionOutlives(..) |
1498 Predicate::WellFormed(..) |
1499 Predicate::ObjectSafe(..) |
1500 Predicate::ClosureKind(..) |
1501 Predicate::ConstEvaluatable(..) => {
1508 /// Represents the bounds declared on a particular set of type
1509 /// parameters. Should eventually be generalized into a flag list of
1510 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1511 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1512 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1513 /// the `GenericPredicates` are expressed in terms of the bound type
1514 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1515 /// represented a set of bounds for some particular instantiation,
1516 /// meaning that the generic parameters have been substituted with
1521 /// struct Foo<T, U: Bar<T>> { ... }
1523 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1524 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1525 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1526 /// [usize:Bar<isize>]]`.
1527 #[derive(Clone, Debug)]
1528 pub struct InstantiatedPredicates<'tcx> {
1529 pub predicates: Vec<Predicate<'tcx>>,
1532 impl<'tcx> InstantiatedPredicates<'tcx> {
1533 pub fn empty() -> InstantiatedPredicates<'tcx> {
1534 InstantiatedPredicates { predicates: vec![] }
1537 pub fn is_empty(&self) -> bool {
1538 self.predicates.is_empty()
1543 /// "Universes" are used during type- and trait-checking in the
1544 /// presence of `for<..>` binders to control what sets of names are
1545 /// visible. Universes are arranged into a tree: the root universe
1546 /// contains names that are always visible. Each child then adds a new
1547 /// set of names that are visible, in addition to those of its parent.
1548 /// We say that the child universe "extends" the parent universe with
1551 /// To make this more concrete, consider this program:
1555 /// fn bar<T>(x: T) {
1556 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1560 /// The struct name `Foo` is in the root universe U0. But the type
1561 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1562 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1563 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1564 /// region `'a` is in a universe U2 that extends U1, because we can
1565 /// name it inside the fn type but not outside.
1567 /// Universes are used to do type- and trait-checking around these
1568 /// "forall" binders (also called **universal quantification**). The
1569 /// idea is that when, in the body of `bar`, we refer to `T` as a
1570 /// type, we aren't referring to any type in particular, but rather a
1571 /// kind of "fresh" type that is distinct from all other types we have
1572 /// actually declared. This is called a **placeholder** type, and we
1573 /// use universes to talk about this. In other words, a type name in
1574 /// universe 0 always corresponds to some "ground" type that the user
1575 /// declared, but a type name in a non-zero universe is a placeholder
1576 /// type -- an idealized representative of "types in general" that we
1577 /// use for checking generic functions.
1578 pub struct UniverseIndex {
1579 DEBUG_FORMAT = "U{}",
1583 impl_stable_hash_for!(struct UniverseIndex { private });
1585 impl UniverseIndex {
1586 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1588 /// Returns the "next" universe index in order -- this new index
1589 /// is considered to extend all previous universes. This
1590 /// corresponds to entering a `forall` quantifier. So, for
1591 /// example, suppose we have this type in universe `U`:
1594 /// for<'a> fn(&'a u32)
1597 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1598 /// new universe that extends `U` -- in this new universe, we can
1599 /// name the region `'a`, but that region was not nameable from
1600 /// `U` because it was not in scope there.
1601 pub fn next_universe(self) -> UniverseIndex {
1602 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1605 /// Returns `true` if `self` can name a name from `other` -- in other words,
1606 /// if the set of names in `self` is a superset of those in
1607 /// `other` (`self >= other`).
1608 pub fn can_name(self, other: UniverseIndex) -> bool {
1609 self.private >= other.private
1612 /// Returns `true` if `self` cannot name some names from `other` -- in other
1613 /// words, if the set of names in `self` is a strict subset of
1614 /// those in `other` (`self < other`).
1615 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1616 self.private < other.private
1620 /// The "placeholder index" fully defines a placeholder region.
1621 /// Placeholder regions are identified by both a **universe** as well
1622 /// as a "bound-region" within that universe. The `bound_region` is
1623 /// basically a name -- distinct bound regions within the same
1624 /// universe are just two regions with an unknown relationship to one
1626 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1627 pub struct Placeholder<T> {
1628 pub universe: UniverseIndex,
1632 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1634 T: HashStable<StableHashingContext<'a>>,
1636 fn hash_stable<W: StableHasherResult>(
1638 hcx: &mut StableHashingContext<'a>,
1639 hasher: &mut StableHasher<W>
1641 self.universe.hash_stable(hcx, hasher);
1642 self.name.hash_stable(hcx, hasher);
1646 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1648 pub type PlaceholderType = Placeholder<BoundVar>;
1650 pub type PlaceholderConst = Placeholder<BoundVar>;
1652 /// When type checking, we use the `ParamEnv` to track
1653 /// details about the set of where-clauses that are in scope at this
1654 /// particular point.
1655 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1656 pub struct ParamEnv<'tcx> {
1657 /// `Obligation`s that the caller must satisfy. This is basically
1658 /// the set of bounds on the in-scope type parameters, translated
1659 /// into `Obligation`s, and elaborated and normalized.
1660 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1662 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1663 /// want `Reveal::All` -- note that this is always paired with an
1664 /// empty environment. To get that, use `ParamEnv::reveal()`.
1665 pub reveal: traits::Reveal,
1667 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1668 /// register that `def_id` (useful for transitioning to the chalk trait
1670 pub def_id: Option<DefId>,
1673 impl<'tcx> ParamEnv<'tcx> {
1674 /// Construct a trait environment suitable for contexts where
1675 /// there are no where-clauses in scope. Hidden types (like `impl
1676 /// Trait`) are left hidden, so this is suitable for ordinary
1679 pub fn empty() -> Self {
1680 Self::new(List::empty(), Reveal::UserFacing, None)
1683 /// Construct a trait environment with no where-clauses in scope
1684 /// where the values of all `impl Trait` and other hidden types
1685 /// are revealed. This is suitable for monomorphized, post-typeck
1686 /// environments like codegen or doing optimizations.
1688 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1689 /// or invoke `param_env.with_reveal_all()`.
1691 pub fn reveal_all() -> Self {
1692 Self::new(List::empty(), Reveal::All, None)
1695 /// Construct a trait environment with the given set of predicates.
1698 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1700 def_id: Option<DefId>
1702 ty::ParamEnv { caller_bounds, reveal, def_id }
1705 /// Returns a new parameter environment with the same clauses, but
1706 /// which "reveals" the true results of projections in all cases
1707 /// (even for associated types that are specializable). This is
1708 /// the desired behavior during codegen and certain other special
1709 /// contexts; normally though we want to use `Reveal::UserFacing`,
1710 /// which is the default.
1711 pub fn with_reveal_all(self) -> Self {
1712 ty::ParamEnv { reveal: Reveal::All, ..self }
1715 /// Returns this same environment but with no caller bounds.
1716 pub fn without_caller_bounds(self) -> Self {
1717 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1720 /// Creates a suitable environment in which to perform trait
1721 /// queries on the given value. When type-checking, this is simply
1722 /// the pair of the environment plus value. But when reveal is set to
1723 /// All, then if `value` does not reference any type parameters, we will
1724 /// pair it with the empty environment. This improves caching and is generally
1727 /// N.B., we preserve the environment when type-checking because it
1728 /// is possible for the user to have wacky where-clauses like
1729 /// `where Box<u32>: Copy`, which are clearly never
1730 /// satisfiable. We generally want to behave as if they were true,
1731 /// although the surrounding function is never reachable.
1732 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1734 Reveal::UserFacing => {
1742 if value.has_placeholders()
1743 || value.needs_infer()
1744 || value.has_param_types()
1752 param_env: self.without_caller_bounds(),
1761 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1762 pub struct ParamEnvAnd<'tcx, T> {
1763 pub param_env: ParamEnv<'tcx>,
1767 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1768 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1769 (self.param_env, self.value)
1773 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1775 T: HashStable<StableHashingContext<'a>>,
1777 fn hash_stable<W: StableHasherResult>(&self,
1778 hcx: &mut StableHashingContext<'a>,
1779 hasher: &mut StableHasher<W>) {
1785 param_env.hash_stable(hcx, hasher);
1786 value.hash_stable(hcx, hasher);
1790 #[derive(Copy, Clone, Debug, HashStable)]
1791 pub struct Destructor {
1792 /// The `DefId` of the destructor method
1797 #[derive(HashStable)]
1798 pub struct AdtFlags: u32 {
1799 const NO_ADT_FLAGS = 0;
1800 /// Indicates whether the ADT is an enum.
1801 const IS_ENUM = 1 << 0;
1802 /// Indicates whether the ADT is a union.
1803 const IS_UNION = 1 << 1;
1804 /// Indicates whether the ADT is a struct.
1805 const IS_STRUCT = 1 << 2;
1806 /// Indicates whether the ADT is a struct and has a constructor.
1807 const HAS_CTOR = 1 << 3;
1808 /// Indicates whether the type is a `PhantomData`.
1809 const IS_PHANTOM_DATA = 1 << 4;
1810 /// Indicates whether the type has a `#[fundamental]` attribute.
1811 const IS_FUNDAMENTAL = 1 << 5;
1812 /// Indicates whether the type is a `Box`.
1813 const IS_BOX = 1 << 6;
1814 /// Indicates whether the type is an `Arc`.
1815 const IS_ARC = 1 << 7;
1816 /// Indicates whether the type is an `Rc`.
1817 const IS_RC = 1 << 8;
1818 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1819 /// (i.e., this flag is never set unless this ADT is an enum).
1820 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1825 #[derive(HashStable)]
1826 pub struct VariantFlags: u32 {
1827 const NO_VARIANT_FLAGS = 0;
1828 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1829 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1833 /// Definition of a variant -- a struct's fields or a enum variant.
1835 pub struct VariantDef {
1836 /// `DefId` that identifies the variant itself.
1837 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1839 /// `DefId` that identifies the variant's constructor.
1840 /// If this variant is a struct variant, then this is `None`.
1841 pub ctor_def_id: Option<DefId>,
1842 /// Variant or struct name.
1844 /// Discriminant of this variant.
1845 pub discr: VariantDiscr,
1846 /// Fields of this variant.
1847 pub fields: Vec<FieldDef>,
1848 /// Type of constructor of variant.
1849 pub ctor_kind: CtorKind,
1850 /// Flags of the variant (e.g. is field list non-exhaustive)?
1851 flags: VariantFlags,
1852 /// Variant is obtained as part of recovering from a syntactic error.
1853 /// May be incomplete or bogus.
1854 pub recovered: bool,
1857 impl<'tcx> VariantDef {
1858 /// Creates a new `VariantDef`.
1860 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1861 /// represents an enum variant).
1863 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1864 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1866 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1867 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1868 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1869 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1870 /// built-in trait), and we do not want to load attributes twice.
1872 /// If someone speeds up attribute loading to not be a performance concern, they can
1873 /// remove this hack and use the constructor `DefId` everywhere.
1877 variant_did: Option<DefId>,
1878 ctor_def_id: Option<DefId>,
1879 discr: VariantDiscr,
1880 fields: Vec<FieldDef>,
1881 ctor_kind: CtorKind,
1887 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1888 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1889 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1892 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1893 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1894 debug!("found non-exhaustive field list for {:?}", parent_did);
1895 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1896 } else if let Some(variant_did) = variant_did {
1897 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1898 debug!("found non-exhaustive field list for {:?}", variant_did);
1899 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1904 def_id: variant_did.unwrap_or(parent_did),
1915 /// Is this field list non-exhaustive?
1917 pub fn is_field_list_non_exhaustive(&self) -> bool {
1918 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1922 impl_stable_hash_for!(struct VariantDef {
1925 ident -> (ident.name),
1933 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1934 pub enum VariantDiscr {
1935 /// Explicit value for this variant, i.e., `X = 123`.
1936 /// The `DefId` corresponds to the embedded constant.
1939 /// The previous variant's discriminant plus one.
1940 /// For efficiency reasons, the distance from the
1941 /// last `Explicit` discriminant is being stored,
1942 /// or `0` for the first variant, if it has none.
1946 #[derive(Debug, HashStable)]
1947 pub struct FieldDef {
1949 #[stable_hasher(project(name))]
1951 pub vis: Visibility,
1954 /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
1956 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1958 /// The initialism *"Adt"* stands for an [*algebraic data type (ADT)*][adt].
1959 /// This is slightly wrong because `union`s are not ADTs.
1960 /// Moreover, Rust only allows recursive data types through indirection.
1962 /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
1964 /// `DefId` of the struct, enum or union item.
1966 /// Variants of the ADT. If this is a struct or union, then there will be a single variant.
1967 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1968 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1970 /// Repr options provided by the user.
1971 pub repr: ReprOptions,
1974 impl PartialOrd for AdtDef {
1975 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1976 Some(self.cmp(&other))
1980 /// There should be only one AdtDef for each `did`, therefore
1981 /// it is fine to implement `Ord` only based on `did`.
1982 impl Ord for AdtDef {
1983 fn cmp(&self, other: &AdtDef) -> Ordering {
1984 self.did.cmp(&other.did)
1988 impl PartialEq for AdtDef {
1989 // AdtDef are always interned and this is part of TyS equality
1991 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1994 impl Eq for AdtDef {}
1996 impl Hash for AdtDef {
1998 fn hash<H: Hasher>(&self, s: &mut H) {
1999 (self as *const AdtDef).hash(s)
2003 impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef {
2004 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
2009 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {}
2012 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
2013 fn hash_stable<W: StableHasherResult>(&self,
2014 hcx: &mut StableHashingContext<'a>,
2015 hasher: &mut StableHasher<W>) {
2017 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
2020 let hash: Fingerprint = CACHE.with(|cache| {
2021 let addr = self as *const AdtDef as usize;
2022 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2030 let mut hasher = StableHasher::new();
2031 did.hash_stable(hcx, &mut hasher);
2032 variants.hash_stable(hcx, &mut hasher);
2033 flags.hash_stable(hcx, &mut hasher);
2034 repr.hash_stable(hcx, &mut hasher);
2040 hash.hash_stable(hcx, hasher);
2044 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2045 pub enum AdtKind { Struct, Union, Enum }
2047 impl Into<DataTypeKind> for AdtKind {
2048 fn into(self) -> DataTypeKind {
2050 AdtKind::Struct => DataTypeKind::Struct,
2051 AdtKind::Union => DataTypeKind::Union,
2052 AdtKind::Enum => DataTypeKind::Enum,
2058 #[derive(RustcEncodable, RustcDecodable, Default)]
2059 pub struct ReprFlags: u8 {
2060 const IS_C = 1 << 0;
2061 const IS_SIMD = 1 << 1;
2062 const IS_TRANSPARENT = 1 << 2;
2063 // Internal only for now. If true, don't reorder fields.
2064 const IS_LINEAR = 1 << 3;
2066 // Any of these flags being set prevent field reordering optimisation.
2067 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2068 ReprFlags::IS_SIMD.bits |
2069 ReprFlags::IS_LINEAR.bits;
2073 impl_stable_hash_for!(struct ReprFlags {
2077 /// Represents the repr options provided by the user,
2078 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2079 pub struct ReprOptions {
2080 pub int: Option<attr::IntType>,
2081 pub align: Option<Align>,
2082 pub pack: Option<Align>,
2083 pub flags: ReprFlags,
2086 impl_stable_hash_for!(struct ReprOptions {
2094 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2095 let mut flags = ReprFlags::empty();
2096 let mut size = None;
2097 let mut max_align: Option<Align> = None;
2098 let mut min_pack: Option<Align> = None;
2099 for attr in tcx.get_attrs(did).iter() {
2100 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2101 flags.insert(match r {
2102 attr::ReprC => ReprFlags::IS_C,
2103 attr::ReprPacked(pack) => {
2104 let pack = Align::from_bytes(pack as u64).unwrap();
2105 min_pack = Some(if let Some(min_pack) = min_pack {
2112 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2113 attr::ReprSimd => ReprFlags::IS_SIMD,
2114 attr::ReprInt(i) => {
2118 attr::ReprAlign(align) => {
2119 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2126 // This is here instead of layout because the choice must make it into metadata.
2127 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2128 flags.insert(ReprFlags::IS_LINEAR);
2130 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2134 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2136 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2138 pub fn packed(&self) -> bool { self.pack.is_some() }
2140 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2142 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2144 pub fn discr_type(&self) -> attr::IntType {
2145 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2148 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2149 /// layout" optimizations, such as representing `Foo<&T>` as a
2151 pub fn inhibit_enum_layout_opt(&self) -> bool {
2152 self.c() || self.int.is_some()
2155 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2156 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2157 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2158 if let Some(pack) = self.pack {
2159 if pack.bytes() == 1 {
2163 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2166 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2167 pub fn inhibit_union_abi_opt(&self) -> bool {
2173 /// Creates a new `AdtDef`.
2178 variants: IndexVec<VariantIdx, VariantDef>,
2181 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2182 let mut flags = AdtFlags::NO_ADT_FLAGS;
2184 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2185 debug!("found non-exhaustive variant list for {:?}", did);
2186 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2189 flags |= match kind {
2190 AdtKind::Enum => AdtFlags::IS_ENUM,
2191 AdtKind::Union => AdtFlags::IS_UNION,
2192 AdtKind::Struct => AdtFlags::IS_STRUCT,
2195 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2196 flags |= AdtFlags::HAS_CTOR;
2199 let attrs = tcx.get_attrs(did);
2200 if attr::contains_name(&attrs, sym::fundamental) {
2201 flags |= AdtFlags::IS_FUNDAMENTAL;
2203 if Some(did) == tcx.lang_items().phantom_data() {
2204 flags |= AdtFlags::IS_PHANTOM_DATA;
2206 if Some(did) == tcx.lang_items().owned_box() {
2207 flags |= AdtFlags::IS_BOX;
2209 if Some(did) == tcx.lang_items().arc() {
2210 flags |= AdtFlags::IS_ARC;
2212 if Some(did) == tcx.lang_items().rc() {
2213 flags |= AdtFlags::IS_RC;
2224 /// Returns `true` if this is a struct.
2226 pub fn is_struct(&self) -> bool {
2227 self.flags.contains(AdtFlags::IS_STRUCT)
2230 /// Returns `true` if this is a union.
2232 pub fn is_union(&self) -> bool {
2233 self.flags.contains(AdtFlags::IS_UNION)
2236 /// Returns `true` if this is a enum.
2238 pub fn is_enum(&self) -> bool {
2239 self.flags.contains(AdtFlags::IS_ENUM)
2242 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2244 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2245 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2248 /// Returns the kind of the ADT.
2250 pub fn adt_kind(&self) -> AdtKind {
2253 } else if self.is_union() {
2260 /// Returns a description of this abstract data type.
2261 pub fn descr(&self) -> &'static str {
2262 match self.adt_kind() {
2263 AdtKind::Struct => "struct",
2264 AdtKind::Union => "union",
2265 AdtKind::Enum => "enum",
2269 /// Returns a description of a variant of this abstract data type.
2271 pub fn variant_descr(&self) -> &'static str {
2272 match self.adt_kind() {
2273 AdtKind::Struct => "struct",
2274 AdtKind::Union => "union",
2275 AdtKind::Enum => "variant",
2279 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2281 pub fn has_ctor(&self) -> bool {
2282 self.flags.contains(AdtFlags::HAS_CTOR)
2285 /// Returns `true` if this type is `#[fundamental]` for the purposes
2286 /// of coherence checking.
2288 pub fn is_fundamental(&self) -> bool {
2289 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2292 /// Returns `true` if this is `PhantomData<T>`.
2294 pub fn is_phantom_data(&self) -> bool {
2295 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2298 /// Returns `true` if this is `Arc<T>`.
2299 pub fn is_arc(&self) -> bool {
2300 self.flags.contains(AdtFlags::IS_ARC)
2303 /// Returns `true` if this is `Rc<T>`.
2304 pub fn is_rc(&self) -> bool {
2305 self.flags.contains(AdtFlags::IS_RC)
2308 /// Returns `true` if this is Box<T>.
2310 pub fn is_box(&self) -> bool {
2311 self.flags.contains(AdtFlags::IS_BOX)
2314 /// Returns `true` if this type has a destructor.
2315 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2316 self.destructor(tcx).is_some()
2319 /// Asserts this is a struct or union and returns its unique variant.
2320 pub fn non_enum_variant(&self) -> &VariantDef {
2321 assert!(self.is_struct() || self.is_union());
2322 &self.variants[VariantIdx::new(0)]
2326 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> &'tcx GenericPredicates<'tcx> {
2327 tcx.predicates_of(self.did)
2330 /// Returns an iterator over all fields contained
2333 pub fn all_fields(&self) -> impl Iterator<Item=&FieldDef> + Clone {
2334 self.variants.iter().flat_map(|v| v.fields.iter())
2337 pub fn is_payloadfree(&self) -> bool {
2338 !self.variants.is_empty() &&
2339 self.variants.iter().all(|v| v.fields.is_empty())
2342 /// Return a `VariantDef` given a variant id.
2343 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2344 self.variants.iter().find(|v| v.def_id == vid)
2345 .expect("variant_with_id: unknown variant")
2348 /// Return a `VariantDef` given a constructor id.
2349 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2350 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2351 .expect("variant_with_ctor_id: unknown variant")
2354 /// Return the index of `VariantDef` given a variant id.
2355 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2356 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2357 .expect("variant_index_with_id: unknown variant").0
2360 /// Return the index of `VariantDef` given a constructor id.
2361 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2362 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2363 .expect("variant_index_with_ctor_id: unknown variant").0
2366 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2368 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2369 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2370 Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
2371 Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) |
2372 Res::SelfCtor(..) => self.non_enum_variant(),
2373 _ => bug!("unexpected res {:?} in variant_of_res", res)
2378 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2379 let param_env = tcx.param_env(expr_did);
2380 let repr_type = self.repr.discr_type();
2381 let substs = InternalSubsts::identity_for_item(tcx, expr_did);
2382 let instance = ty::Instance::new(expr_did, substs);
2383 let cid = GlobalId {
2387 match tcx.const_eval(param_env.and(cid)) {
2389 // FIXME: Find the right type and use it instead of `val.ty` here
2390 if let Some(b) = val.try_eval_bits(tcx, param_env, val.ty) {
2391 trace!("discriminants: {} ({:?})", b, repr_type);
2397 info!("invalid enum discriminant: {:#?}", val);
2398 crate::mir::interpret::struct_error(
2399 tcx.at(tcx.def_span(expr_did)),
2400 "constant evaluation of enum discriminant resulted in non-integer",
2405 Err(ErrorHandled::Reported) => {
2406 if !expr_did.is_local() {
2407 span_bug!(tcx.def_span(expr_did),
2408 "variant discriminant evaluation succeeded \
2409 in its crate but failed locally");
2413 Err(ErrorHandled::TooGeneric) => span_bug!(
2414 tcx.def_span(expr_did),
2415 "enum discriminant depends on generic arguments",
2421 pub fn discriminants(
2424 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2425 let repr_type = self.repr.discr_type();
2426 let initial = repr_type.initial_discriminant(tcx);
2427 let mut prev_discr = None::<Discr<'tcx>>;
2428 self.variants.iter_enumerated().map(move |(i, v)| {
2429 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2430 if let VariantDiscr::Explicit(expr_did) = v.discr {
2431 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2435 prev_discr = Some(discr);
2442 pub fn variant_range(&self) -> Range<VariantIdx> {
2443 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2446 /// Computes the discriminant value used by a specific variant.
2447 /// Unlike `discriminants`, this is (amortized) constant-time,
2448 /// only doing at most one query for evaluating an explicit
2449 /// discriminant (the last one before the requested variant),
2450 /// assuming there are no constant-evaluation errors there.
2452 pub fn discriminant_for_variant(
2455 variant_index: VariantIdx,
2457 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2458 let explicit_value = val
2459 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2460 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
2461 explicit_value.checked_add(tcx, offset as u128).0
2464 /// Yields a `DefId` for the discriminant and an offset to add to it
2465 /// Alternatively, if there is no explicit discriminant, returns the
2466 /// inferred discriminant directly.
2467 pub fn discriminant_def_for_variant(
2469 variant_index: VariantIdx,
2470 ) -> (Option<DefId>, u32) {
2471 let mut explicit_index = variant_index.as_u32();
2474 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2475 ty::VariantDiscr::Relative(0) => {
2479 ty::VariantDiscr::Relative(distance) => {
2480 explicit_index -= distance;
2482 ty::VariantDiscr::Explicit(did) => {
2483 expr_did = Some(did);
2488 (expr_did, variant_index.as_u32() - explicit_index)
2491 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2492 tcx.adt_destructor(self.did)
2495 /// Returns a list of types such that `Self: Sized` if and only
2496 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2498 /// Oddly enough, checking that the sized-constraint is `Sized` is
2499 /// actually more expressive than checking all members:
2500 /// the `Sized` trait is inductive, so an associated type that references
2501 /// `Self` would prevent its containing ADT from being `Sized`.
2503 /// Due to normalization being eager, this applies even if
2504 /// the associated type is behind a pointer (e.g., issue #31299).
2505 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2506 tcx.adt_sized_constraint(self.did).0
2509 fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> {
2510 let result = match ty.kind {
2511 Bool | Char | Int(..) | Uint(..) | Float(..) |
2512 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2513 Array(..) | Closure(..) | Generator(..) | Never => {
2522 GeneratorWitness(..) => {
2523 // these are never sized - return the target type
2530 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2534 Adt(adt, substs) => {
2536 let adt_tys = adt.sized_constraint(tcx);
2537 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2540 .map(|ty| ty.subst(tcx, substs))
2541 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2545 Projection(..) | Opaque(..) => {
2546 // must calculate explicitly.
2547 // FIXME: consider special-casing always-Sized projections
2551 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2554 // perf hack: if there is a `T: Sized` bound, then
2555 // we know that `T` is Sized and do not need to check
2558 let sized_trait = match tcx.lang_items().sized_trait() {
2560 _ => return vec![ty]
2562 let sized_predicate = Binder::dummy(TraitRef {
2563 def_id: sized_trait,
2564 substs: tcx.mk_substs_trait(ty, &[])
2566 let predicates = &tcx.predicates_of(self.did).predicates;
2567 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2577 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2581 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2586 impl<'tcx> FieldDef {
2587 /// Returns the type of this field. The `subst` is typically obtained
2588 /// via the second field of `TyKind::AdtDef`.
2589 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2590 tcx.type_of(self.did).subst(tcx, subst)
2594 /// Represents the various closure traits in the language. This
2595 /// will determine the type of the environment (`self`, in the
2596 /// desugaring) argument that the closure expects.
2598 /// You can get the environment type of a closure using
2599 /// `tcx.closure_env_ty()`.
2600 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2601 RustcEncodable, RustcDecodable, HashStable)]
2602 pub enum ClosureKind {
2603 // Warning: Ordering is significant here! The ordering is chosen
2604 // because the trait Fn is a subtrait of FnMut and so in turn, and
2605 // hence we order it so that Fn < FnMut < FnOnce.
2611 impl<'tcx> ClosureKind {
2612 // This is the initial value used when doing upvar inference.
2613 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2615 pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
2617 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem, None),
2618 ClosureKind::FnMut => {
2619 tcx.require_lang_item(FnMutTraitLangItem, None)
2621 ClosureKind::FnOnce => {
2622 tcx.require_lang_item(FnOnceTraitLangItem, None)
2627 /// Returns `true` if this a type that impls this closure kind
2628 /// must also implement `other`.
2629 pub fn extends(self, other: ty::ClosureKind) -> bool {
2630 match (self, other) {
2631 (ClosureKind::Fn, ClosureKind::Fn) => true,
2632 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2633 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2634 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2635 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2636 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2641 /// Returns the representative scalar type for this closure kind.
2642 /// See `TyS::to_opt_closure_kind` for more details.
2643 pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
2645 ty::ClosureKind::Fn => tcx.types.i8,
2646 ty::ClosureKind::FnMut => tcx.types.i16,
2647 ty::ClosureKind::FnOnce => tcx.types.i32,
2652 impl<'tcx> TyS<'tcx> {
2653 /// Iterator that walks `self` and any types reachable from
2654 /// `self`, in depth-first order. Note that just walks the types
2655 /// that appear in `self`, it does not descend into the fields of
2656 /// structs or variants. For example:
2659 /// isize => { isize }
2660 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2661 /// [isize] => { [isize], isize }
2663 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2664 TypeWalker::new(self)
2667 /// Iterator that walks the immediate children of `self`. Hence
2668 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2669 /// (but not `i32`, like `walk`).
2670 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2671 walk::walk_shallow(self)
2674 /// Walks `ty` and any types appearing within `ty`, invoking the
2675 /// callback `f` on each type. If the callback returns `false`, then the
2676 /// children of the current type are ignored.
2678 /// Note: prefer `ty.walk()` where possible.
2679 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2680 where F: FnMut(Ty<'tcx>) -> bool
2682 let mut walker = self.walk();
2683 while let Some(ty) = walker.next() {
2685 walker.skip_current_subtree();
2692 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2694 hir::MutMutable => MutBorrow,
2695 hir::MutImmutable => ImmBorrow,
2699 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2700 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2701 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2703 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2705 MutBorrow => hir::MutMutable,
2706 ImmBorrow => hir::MutImmutable,
2708 // We have no type corresponding to a unique imm borrow, so
2709 // use `&mut`. It gives all the capabilities of an `&uniq`
2710 // and hence is a safe "over approximation".
2711 UniqueImmBorrow => hir::MutMutable,
2715 pub fn to_user_str(&self) -> &'static str {
2717 MutBorrow => "mutable",
2718 ImmBorrow => "immutable",
2719 UniqueImmBorrow => "uniquely immutable",
2724 #[derive(Debug, Clone)]
2725 pub enum Attributes<'tcx> {
2726 Owned(Lrc<[ast::Attribute]>),
2727 Borrowed(&'tcx [ast::Attribute]),
2730 impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
2731 type Target = [ast::Attribute];
2733 fn deref(&self) -> &[ast::Attribute] {
2735 &Attributes::Owned(ref data) => &data,
2736 &Attributes::Borrowed(data) => data
2741 #[derive(Debug, PartialEq, Eq)]
2742 pub enum ImplOverlapKind {
2743 /// These impls are always allowed to overlap.
2745 /// These impls are allowed to overlap, but that raises
2746 /// an issue #33140 future-compatibility warning.
2748 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2749 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2751 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2752 /// that difference, making what reduces to the following set of impls:
2756 /// impl Trait for dyn Send + Sync {}
2757 /// impl Trait for dyn Sync + Send {}
2760 /// Obviously, once we made these types be identical, that code causes a coherence
2761 /// error and a fairly big headache for us. However, luckily for us, the trait
2762 /// `Trait` used in this case is basically a marker trait, and therefore having
2763 /// overlapping impls for it is sound.
2765 /// To handle this, we basically regard the trait as a marker trait, with an additional
2766 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2767 /// it has the following restrictions:
2769 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2771 /// 2. The trait-ref of both impls must be equal.
2772 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2774 /// 4. Neither of the impls can have any where-clauses.
2776 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2780 impl<'tcx> TyCtxt<'tcx> {
2781 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
2782 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2785 /// Returns an iterator of the `DefId`s for all body-owners in this
2786 /// crate. If you would prefer to iterate over the bodies
2787 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2788 pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
2792 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2795 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2796 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2797 f(self.hir().body_owner_def_id(body_id))
2801 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
2802 self.associated_items(id)
2803 .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
2807 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2808 self.associated_items(did).any(|item| {
2809 item.relevant_for_never()
2813 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
2814 self.hir().as_local_hir_id(def_id).and_then(|hir_id| self.hir().get(hir_id).ident())
2817 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
2818 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2819 match self.hir().get(hir_id) {
2820 Node::TraitItem(_) | Node::ImplItem(_) => true,
2824 match self.def_kind(def_id).expect("no def for `DefId`") {
2827 | DefKind::AssocTy => true,
2832 if is_associated_item {
2833 Some(self.associated_item(def_id))
2839 fn associated_item_from_trait_item_ref(self,
2840 parent_def_id: DefId,
2841 parent_vis: &hir::Visibility,
2842 trait_item_ref: &hir::TraitItemRef)
2844 let def_id = self.hir().local_def_id(trait_item_ref.id.hir_id);
2845 let (kind, has_self) = match trait_item_ref.kind {
2846 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2847 hir::AssocItemKind::Method { has_self } => {
2848 (ty::AssocKind::Method, has_self)
2850 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2851 hir::AssocItemKind::OpaqueTy => bug!("only impls can have opaque types"),
2855 ident: trait_item_ref.ident,
2857 // Visibility of trait items is inherited from their traits.
2858 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2859 defaultness: trait_item_ref.defaultness,
2861 container: TraitContainer(parent_def_id),
2862 method_has_self_argument: has_self
2866 fn associated_item_from_impl_item_ref(self,
2867 parent_def_id: DefId,
2868 impl_item_ref: &hir::ImplItemRef)
2870 let def_id = self.hir().local_def_id(impl_item_ref.id.hir_id);
2871 let (kind, has_self) = match impl_item_ref.kind {
2872 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2873 hir::AssocItemKind::Method { has_self } => {
2874 (ty::AssocKind::Method, has_self)
2876 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2877 hir::AssocItemKind::OpaqueTy => (ty::AssocKind::OpaqueTy, false),
2881 ident: impl_item_ref.ident,
2883 // Visibility of trait impl items doesn't matter.
2884 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2885 defaultness: impl_item_ref.defaultness,
2887 container: ImplContainer(parent_def_id),
2888 method_has_self_argument: has_self
2892 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2893 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2896 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2897 variant.fields.iter().position(|field| {
2898 self.hygienic_eq(ident, field.ident, variant.def_id)
2902 pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
2903 // Ideally, we would use `-> impl Iterator` here, but it falls
2904 // afoul of the conservative "capture [restrictions]" we put
2905 // in place, so we use a hand-written iterator.
2907 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2908 AssocItemsIterator {
2910 def_ids: self.associated_item_def_ids(def_id),
2915 /// Returns `true` if the impls are the same polarity and the trait either
2916 /// has no items or is annotated #[marker] and prevents item overrides.
2917 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2918 -> Option<ImplOverlapKind>
2920 // If either trait impl references an error, they're allowed to overlap,
2921 // as one of them essentially doesn't exist.
2922 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error()) ||
2923 self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error()) {
2924 return Some(ImplOverlapKind::Permitted);
2927 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2928 (ImplPolarity::Reservation, _) |
2929 (_, ImplPolarity::Reservation) => {
2930 // `#[rustc_reservation_impl]` impls don't overlap with anything
2931 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2933 return Some(ImplOverlapKind::Permitted);
2935 (ImplPolarity::Positive, ImplPolarity::Negative) |
2936 (ImplPolarity::Negative, ImplPolarity::Positive) => {
2937 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2938 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2942 (ImplPolarity::Positive, ImplPolarity::Positive) |
2943 (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2946 let is_marker_overlap = if self.features().overlapping_marker_traits {
2947 let trait1_is_empty = self.impl_trait_ref(def_id1)
2948 .map_or(false, |trait_ref| {
2949 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2951 let trait2_is_empty = self.impl_trait_ref(def_id2)
2952 .map_or(false, |trait_ref| {
2953 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2955 trait1_is_empty && trait2_is_empty
2957 let is_marker_impl = |def_id: DefId| -> bool {
2958 let trait_ref = self.impl_trait_ref(def_id);
2959 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2961 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2965 if is_marker_overlap {
2966 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2968 Some(ImplOverlapKind::Permitted)
2970 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2971 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2972 if self_ty1 == self_ty2 {
2973 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2975 return Some(ImplOverlapKind::Issue33140);
2977 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2978 def_id1, def_id2, self_ty1, self_ty2);
2983 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2989 /// Returns `ty::VariantDef` if `res` refers to a struct,
2990 /// or variant or their constructors, panics otherwise.
2991 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2993 Res::Def(DefKind::Variant, did) => {
2994 let enum_did = self.parent(did).unwrap();
2995 self.adt_def(enum_did).variant_with_id(did)
2997 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
2998 self.adt_def(did).non_enum_variant()
3000 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
3001 let variant_did = self.parent(variant_ctor_did).unwrap();
3002 let enum_did = self.parent(variant_did).unwrap();
3003 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
3005 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
3006 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
3007 self.adt_def(struct_did).non_enum_variant()
3009 _ => bug!("expect_variant_res used with unexpected res {:?}", res)
3013 pub fn item_name(self, id: DefId) -> Symbol {
3014 if id.index == CRATE_DEF_INDEX {
3015 self.original_crate_name(id.krate)
3017 let def_key = self.def_key(id);
3018 match def_key.disambiguated_data.data {
3019 // The name of a constructor is that of its parent.
3020 hir_map::DefPathData::Ctor =>
3021 self.item_name(DefId {
3023 index: def_key.parent.unwrap()
3025 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
3026 bug!("item_name: no name for {:?}", self.def_path(id));
3032 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
3033 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
3035 ty::InstanceDef::Item(did) => {
3036 self.optimized_mir(did)
3038 ty::InstanceDef::VtableShim(..) |
3039 ty::InstanceDef::Intrinsic(..) |
3040 ty::InstanceDef::FnPtrShim(..) |
3041 ty::InstanceDef::Virtual(..) |
3042 ty::InstanceDef::ClosureOnceShim { .. } |
3043 ty::InstanceDef::DropGlue(..) |
3044 ty::InstanceDef::CloneShim(..) => {
3045 self.mir_shims(instance)
3050 /// Gets the attributes of a definition.
3051 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
3052 if let Some(id) = self.hir().as_local_hir_id(did) {
3053 Attributes::Borrowed(self.hir().attrs(id))
3055 Attributes::Owned(self.item_attrs(did))
3059 /// Determines whether an item is annotated with an attribute.
3060 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
3061 attr::contains_name(&self.get_attrs(did), attr)
3064 /// Returns `true` if this is an `auto trait`.
3065 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3066 self.trait_def(trait_def_id).has_auto_impl
3069 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3070 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3073 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3074 /// If it implements no trait, returns `None`.
3075 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3076 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3079 /// If the given defid describes a method belonging to an impl, returns the
3080 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3081 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3082 let item = if def_id.krate != LOCAL_CRATE {
3083 if let Some(DefKind::Method) = self.def_kind(def_id) {
3084 Some(self.associated_item(def_id))
3089 self.opt_associated_item(def_id)
3092 item.and_then(|trait_item|
3093 match trait_item.container {
3094 TraitContainer(_) => None,
3095 ImplContainer(def_id) => Some(def_id),
3100 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3101 /// with the name of the crate containing the impl.
3102 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3103 if impl_did.is_local() {
3104 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3105 Ok(self.hir().span(hir_id))
3107 Err(self.crate_name(impl_did.krate))
3111 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3112 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3113 /// definition's parent/scope to perform comparison.
3114 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3115 // We could use `Ident::eq` here, but we deliberately don't. The name
3116 // comparison fails frequently, and we want to avoid the expensive
3117 // `modern()` calls required for the span comparison whenever possible.
3118 use_name.name == def_name.name &&
3119 use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
3120 self.expansion_that_defined(def_parent_def_id))
3123 fn expansion_that_defined(self, scope: DefId) -> ExpnId {
3125 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3126 _ => ExpnId::root(),
3130 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
3131 ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
3135 pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
3137 let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
3138 Some(actual_expansion) =>
3139 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3140 None => self.hir().get_module_parent(block),
3146 pub struct AssocItemsIterator<'tcx> {
3148 def_ids: &'tcx [DefId],
3152 impl Iterator for AssocItemsIterator<'_> {
3153 type Item = AssocItem;
3155 fn next(&mut self) -> Option<AssocItem> {
3156 let def_id = self.def_ids.get(self.next_index)?;
3157 self.next_index += 1;
3158 Some(self.tcx.associated_item(*def_id))
3162 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
3163 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3164 let parent_id = tcx.hir().get_parent_item(id);
3165 let parent_def_id = tcx.hir().local_def_id(parent_id);
3166 let parent_item = tcx.hir().expect_item(parent_id);
3167 match parent_item.kind {
3168 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3169 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3170 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3172 debug_assert_eq!(assoc_item.def_id, def_id);
3177 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3178 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3179 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3182 debug_assert_eq!(assoc_item.def_id, def_id);
3190 span_bug!(parent_item.span,
3191 "unexpected parent of trait or impl item or item not found: {:?}",
3195 #[derive(Clone, HashStable)]
3196 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3198 /// Calculates the `Sized` constraint.
3200 /// In fact, there are only a few options for the types in the constraint:
3201 /// - an obviously-unsized type
3202 /// - a type parameter or projection whose Sizedness can't be known
3203 /// - a tuple of type parameters or projections, if there are multiple
3205 /// - a Error, if a type contained itself. The representability
3206 /// check should catch this case.
3207 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
3208 let def = tcx.adt_def(def_id);
3210 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3213 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3216 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3218 AdtSizedConstraint(result)
3221 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
3222 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3223 let item = tcx.hir().expect_item(id);
3225 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3226 tcx.arena.alloc_from_iter(
3227 trait_item_refs.iter()
3228 .map(|trait_item_ref| trait_item_ref.id)
3229 .map(|id| tcx.hir().local_def_id(id.hir_id))
3232 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3233 tcx.arena.alloc_from_iter(
3234 impl_item_refs.iter()
3235 .map(|impl_item_ref| impl_item_ref.id)
3236 .map(|id| tcx.hir().local_def_id(id.hir_id))
3239 hir::ItemKind::TraitAlias(..) => &[],
3240 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3244 fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
3245 tcx.hir().span_if_local(def_id).unwrap()
3248 /// If the given `DefId` describes an item belonging to a trait,
3249 /// returns the `DefId` of the trait that the trait item belongs to;
3250 /// otherwise, returns `None`.
3251 fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3252 tcx.opt_associated_item(def_id)
3253 .and_then(|associated_item| {
3254 match associated_item.container {
3255 TraitContainer(def_id) => Some(def_id),
3256 ImplContainer(_) => None
3261 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3262 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3263 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3264 if let Node::Item(item) = tcx.hir().get(hir_id) {
3265 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
3266 return opaque_ty.impl_trait_fn;
3273 /// See `ParamEnv` struct definition for details.
3274 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
3275 // The param_env of an impl Trait type is its defining function's param_env
3276 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3277 return param_env(tcx, parent);
3279 // Compute the bounds on Self and the type parameters.
3281 let InstantiatedPredicates { predicates } =
3282 tcx.predicates_of(def_id).instantiate_identity(tcx);
3284 // Finally, we have to normalize the bounds in the environment, in
3285 // case they contain any associated type projections. This process
3286 // can yield errors if the put in illegal associated types, like
3287 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3288 // report these errors right here; this doesn't actually feel
3289 // right to me, because constructing the environment feels like a
3290 // kind of a "idempotent" action, but I'm not sure where would be
3291 // a better place. In practice, we construct environments for
3292 // every fn once during type checking, and we'll abort if there
3293 // are any errors at that point, so after type checking you can be
3294 // sure that this will succeed without errors anyway.
3296 let unnormalized_env = ty::ParamEnv::new(
3297 tcx.intern_predicates(&predicates),
3298 traits::Reveal::UserFacing,
3299 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3302 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3303 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
3305 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3306 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3309 fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
3310 assert_eq!(crate_num, LOCAL_CRATE);
3311 tcx.sess.local_crate_disambiguator()
3314 fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
3315 assert_eq!(crate_num, LOCAL_CRATE);
3316 tcx.crate_name.clone()
3319 fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
3320 assert_eq!(crate_num, LOCAL_CRATE);
3321 tcx.hir().crate_hash
3324 fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
3325 match instance_def {
3326 InstanceDef::Item(..) |
3327 InstanceDef::DropGlue(..) => {
3328 let mir = tcx.instance_mir(instance_def);
3329 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3331 // Estimate the size of other compiler-generated shims to be 1.
3336 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3338 /// See [`ImplOverlapKind::Issue33140`] for more details.
3339 fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
3340 debug!("issue33140_self_ty({:?})", def_id);
3342 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3343 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3346 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3348 let is_marker_like =
3349 tcx.impl_polarity(def_id) == ty::ImplPolarity::Positive &&
3350 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3352 // Check whether these impls would be ok for a marker trait.
3353 if !is_marker_like {
3354 debug!("issue33140_self_ty - not marker-like!");
3358 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3359 if trait_ref.substs.len() != 1 {
3360 debug!("issue33140_self_ty - impl has substs!");
3364 let predicates = tcx.predicates_of(def_id);
3365 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3366 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3370 let self_ty = trait_ref.self_ty();
3371 let self_ty_matches = match self_ty.kind {
3372 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3376 if self_ty_matches {
3377 debug!("issue33140_self_ty - MATCHES!");
3380 debug!("issue33140_self_ty - non-matching self type");
3385 /// Check if a function is async.
3386 fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
3387 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap_or_else(|| {
3388 bug!("asyncness: expected local `DefId`, got `{:?}`", def_id)
3391 let node = tcx.hir().get(hir_id);
3393 let fn_like = hir::map::blocks::FnLikeNode::from_node(node).unwrap_or_else(|| {
3394 bug!("asyncness: expected fn-like node but got `{:?}`", def_id);
3401 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3402 context::provide(providers);
3403 erase_regions::provide(providers);
3404 layout::provide(providers);
3405 util::provide(providers);
3406 constness::provide(providers);
3407 *providers = ty::query::Providers {
3410 associated_item_def_ids,
3411 adt_sized_constraint,
3415 crate_disambiguator,
3416 original_crate_name,
3418 trait_impls_of: trait_def::trait_impls_of_provider,
3419 instance_def_size_estimate,
3425 /// A map for the local crate mapping each type to a vector of its
3426 /// inherent impls. This is not meant to be used outside of coherence;
3427 /// rather, you should request the vector for a specific type via
3428 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3429 /// (constructing this map requires touching the entire crate).
3430 #[derive(Clone, Debug, Default, HashStable)]
3431 pub struct CrateInherentImpls {
3432 pub inherent_impls: DefIdMap<Vec<DefId>>,
3435 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3436 pub struct SymbolName {
3437 // FIXME: we don't rely on interning or equality here - better have
3438 // this be a `&'tcx str`.
3439 pub name: InternedString
3442 impl_stable_hash_for!(struct self::SymbolName {
3447 pub fn new(name: &str) -> SymbolName {
3449 name: InternedString::intern(name)
3454 impl fmt::Display for SymbolName {
3455 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3456 fmt::Display::fmt(&self.name, fmt)
3460 impl fmt::Debug for SymbolName {
3461 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3462 fmt::Display::fmt(&self.name, fmt)