1 // ignore-tidy-filelength
3 #![allow(usage_of_ty_tykind)]
5 pub use self::Variance::*;
6 pub use self::AssociatedItemContainer::*;
7 pub use self::BorrowKind::*;
8 pub use self::IntVarValue::*;
9 pub use self::fold::TypeFoldable;
11 use crate::hir::{map as hir_map, FreevarMap, GlobMap, TraitMap};
12 use crate::hir::{HirId, Node};
13 use crate::hir::def::{Def, CtorOf, CtorKind, ExportMap};
14 use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
15 use rustc_data_structures::svh::Svh;
16 use rustc_macros::HashStable;
17 use crate::ich::Fingerprint;
18 use crate::ich::StableHashingContext;
19 use crate::infer::canonical::Canonical;
20 use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
21 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
23 use crate::mir::interpret::{GlobalId, ErrorHandled};
24 use crate::mir::GeneratorLayout;
25 use crate::session::CrateDisambiguator;
26 use crate::traits::{self, Reveal};
28 use crate::ty::layout::VariantIdx;
29 use crate::ty::subst::{Subst, InternalSubsts, SubstsRef};
30 use crate::ty::util::{IntTypeExt, Discr};
31 use crate::ty::walk::TypeWalker;
32 use crate::util::captures::Captures;
33 use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap};
34 use arena::SyncDroplessArena;
35 use crate::session::DataTypeKind;
37 use serialize::{self, Encodable, Encoder};
38 use std::cell::RefCell;
39 use std::cmp::{self, Ordering};
41 use std::hash::{Hash, Hasher};
43 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
46 use syntax::ast::{self, Name, Ident, NodeId};
48 use syntax::ext::hygiene::Mark;
49 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
53 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
54 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
59 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
60 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
61 pub use self::sty::{InferTy, ParamTy, ParamConst, InferConst, ProjectionTy, ExistentialPredicate};
62 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
63 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
64 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
65 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
66 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
67 pub use self::sty::RegionKind;
68 pub use self::sty::{TyVid, IntVid, FloatVid, ConstVid, RegionVid};
69 pub use self::sty::BoundRegion::*;
70 pub use self::sty::InferTy::*;
71 pub use self::sty::RegionKind::*;
72 pub use self::sty::TyKind::*;
74 pub use self::binding::BindingMode;
75 pub use self::binding::BindingMode::*;
77 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
78 pub use self::context::{Lift, TypeckTables, CtxtInterners, GlobalCtxt};
79 pub use self::context::{
80 UserTypeAnnotationIndex, UserType, CanonicalUserType,
81 CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
84 pub use self::instance::{Instance, InstanceDef};
86 pub use self::trait_def::TraitDef;
88 pub use self::query::queries;
101 pub mod inhabitedness;
117 mod structural_impls;
123 pub struct Resolutions {
124 pub freevars: FreevarMap,
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 AssociatedItemContainer {
137 TraitContainer(DefId),
138 ImplContainer(DefId),
141 impl AssociatedItemContainer {
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, Debug, PartialEq, HashStable)]
171 pub struct AssociatedItem {
173 #[stable_hasher(project(name))]
175 pub kind: AssociatedKind,
177 pub defaultness: hir::Defaultness,
178 pub container: AssociatedItemContainer,
180 /// Whether this is a method with an explicit self
181 /// as its first argument, allowing method calls.
182 pub method_has_self_argument: bool,
185 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable, HashStable)]
186 pub enum AssociatedKind {
193 impl AssociatedItem {
194 pub fn def(&self) -> Def {
196 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
197 AssociatedKind::Method => Def::Method(self.def_id),
198 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
199 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
203 /// Tests whether the associated item admits a non-trivial implementation
205 pub fn relevant_for_never<'tcx>(&self) -> bool {
207 AssociatedKind::Existential |
208 AssociatedKind::Const |
209 AssociatedKind::Type => true,
210 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
211 AssociatedKind::Method => !self.method_has_self_argument,
215 pub fn signature<'a, 'tcx>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String {
217 ty::AssociatedKind::Method => {
218 // We skip the binder here because the binder would deanonymize all
219 // late-bound regions, and we don't want method signatures to show up
220 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
221 // regions just fine, showing `fn(&MyType)`.
222 tcx.fn_sig(self.def_id).skip_binder().to_string()
224 ty::AssociatedKind::Type => format!("type {};", self.ident),
225 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
226 ty::AssociatedKind::Const => {
227 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
233 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
234 pub enum Visibility {
235 /// Visible everywhere (including in other crates).
237 /// Visible only in the given crate-local module.
239 /// Not visible anywhere in the local crate. This is the visibility of private external items.
243 pub trait DefIdTree: Copy {
244 fn parent(self, id: DefId) -> Option<DefId>;
246 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
247 if descendant.krate != ancestor.krate {
251 while descendant != ancestor {
252 match self.parent(descendant) {
253 Some(parent) => descendant = parent,
254 None => return false,
261 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
262 fn parent(self, id: DefId) -> Option<DefId> {
263 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
268 pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_, '_, '_>) -> Self {
269 match visibility.node {
270 hir::VisibilityKind::Public => Visibility::Public,
271 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
272 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
273 // If there is no resolution, `resolve` will have already reported an error, so
274 // assume that the visibility is public to avoid reporting more privacy errors.
275 Def::Err => Visibility::Public,
276 def => Visibility::Restricted(def.def_id()),
278 hir::VisibilityKind::Inherited => {
279 Visibility::Restricted(tcx.hir().get_module_parent_by_hir_id(id))
284 /// Returns `true` if an item with this visibility is accessible from the given block.
285 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
286 let restriction = match self {
287 // Public items are visible everywhere.
288 Visibility::Public => return true,
289 // Private items from other crates are visible nowhere.
290 Visibility::Invisible => return false,
291 // Restricted items are visible in an arbitrary local module.
292 Visibility::Restricted(other) if other.krate != module.krate => return false,
293 Visibility::Restricted(module) => module,
296 tree.is_descendant_of(module, restriction)
299 /// Returns `true` if this visibility is at least as accessible as the given visibility
300 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
301 let vis_restriction = match vis {
302 Visibility::Public => return self == Visibility::Public,
303 Visibility::Invisible => return true,
304 Visibility::Restricted(module) => module,
307 self.is_accessible_from(vis_restriction, tree)
310 // Returns `true` if this item is visible anywhere in the local crate.
311 pub fn is_visible_locally(self) -> bool {
313 Visibility::Public => true,
314 Visibility::Restricted(def_id) => def_id.is_local(),
315 Visibility::Invisible => false,
320 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash, HashStable)]
322 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
323 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
324 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
325 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
328 /// The crate variances map is computed during typeck and contains the
329 /// variance of every item in the local crate. You should not use it
330 /// directly, because to do so will make your pass dependent on the
331 /// HIR of every item in the local crate. Instead, use
332 /// `tcx.variances_of()` to get the variance for a *particular*
334 #[derive(HashStable)]
335 pub struct CrateVariancesMap<'tcx> {
336 /// For each item with generics, maps to a vector of the variance
337 /// of its generics. If an item has no generics, it will have no
339 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
343 /// `a.xform(b)` combines the variance of a context with the
344 /// variance of a type with the following meaning. If we are in a
345 /// context with variance `a`, and we encounter a type argument in
346 /// a position with variance `b`, then `a.xform(b)` is the new
347 /// variance with which the argument appears.
353 /// Here, the "ambient" variance starts as covariant. `*mut T` is
354 /// invariant with respect to `T`, so the variance in which the
355 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
356 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
357 /// respect to its type argument `T`, and hence the variance of
358 /// the `i32` here is `Invariant.xform(Covariant)`, which results
359 /// (again) in `Invariant`.
363 /// fn(*const Vec<i32>, *mut Vec<i32)
365 /// The ambient variance is covariant. A `fn` type is
366 /// contravariant with respect to its parameters, so the variance
367 /// within which both pointer types appear is
368 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
369 /// T` is covariant with respect to `T`, so the variance within
370 /// which the first `Vec<i32>` appears is
371 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
372 /// is true for its `i32` argument. In the `*mut T` case, the
373 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
374 /// and hence the outermost type is `Invariant` with respect to
375 /// `Vec<i32>` (and its `i32` argument).
377 /// Source: Figure 1 of "Taming the Wildcards:
378 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
379 pub fn xform(self, v: ty::Variance) -> ty::Variance {
381 // Figure 1, column 1.
382 (ty::Covariant, ty::Covariant) => ty::Covariant,
383 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
384 (ty::Covariant, ty::Invariant) => ty::Invariant,
385 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
387 // Figure 1, column 2.
388 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
389 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
390 (ty::Contravariant, ty::Invariant) => ty::Invariant,
391 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
393 // Figure 1, column 3.
394 (ty::Invariant, _) => ty::Invariant,
396 // Figure 1, column 4.
397 (ty::Bivariant, _) => ty::Bivariant,
402 // Contains information needed to resolve types and (in the future) look up
403 // the types of AST nodes.
404 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
405 pub struct CReaderCacheKey {
410 // Flags that we track on types. These flags are propagated upwards
411 // through the type during type construction, so that we can quickly
412 // check whether the type has various kinds of types in it without
413 // recursing over the type itself.
415 pub struct TypeFlags: u32 {
416 const HAS_PARAMS = 1 << 0;
417 const HAS_SELF = 1 << 1;
418 const HAS_TY_INFER = 1 << 2;
419 const HAS_RE_INFER = 1 << 3;
420 const HAS_RE_PLACEHOLDER = 1 << 4;
422 /// Does this have any `ReEarlyBound` regions? Used to
423 /// determine whether substitition is required, since those
424 /// represent regions that are bound in a `ty::Generics` and
425 /// hence may be substituted.
426 const HAS_RE_EARLY_BOUND = 1 << 5;
428 /// Does this have any region that "appears free" in the type?
429 /// Basically anything but `ReLateBound` and `ReErased`.
430 const HAS_FREE_REGIONS = 1 << 6;
432 /// Is an error type reachable?
433 const HAS_TY_ERR = 1 << 7;
434 const HAS_PROJECTION = 1 << 8;
436 // FIXME: Rename this to the actual property since it's used for generators too
437 const HAS_TY_CLOSURE = 1 << 9;
439 /// `true` if there are "names" of types and regions and so forth
440 /// that are local to a particular fn
441 const HAS_FREE_LOCAL_NAMES = 1 << 10;
443 /// Present if the type belongs in a local type context.
444 /// Only set for Infer other than Fresh.
445 const KEEP_IN_LOCAL_TCX = 1 << 11;
447 // Is there a projection that does not involve a bound region?
448 // Currently we can't normalize projections w/ bound regions.
449 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
451 /// Does this have any `ReLateBound` regions? Used to check
452 /// if a global bound is safe to evaluate.
453 const HAS_RE_LATE_BOUND = 1 << 13;
455 const HAS_TY_PLACEHOLDER = 1 << 14;
457 const HAS_CT_INFER = 1 << 15;
458 const HAS_CT_PLACEHOLDER = 1 << 16;
460 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
461 TypeFlags::HAS_SELF.bits |
462 TypeFlags::HAS_RE_EARLY_BOUND.bits;
464 /// Flags representing the nominal content of a type,
465 /// computed by FlagsComputation. If you add a new nominal
466 /// flag, it should be added here too.
467 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
468 TypeFlags::HAS_SELF.bits |
469 TypeFlags::HAS_TY_INFER.bits |
470 TypeFlags::HAS_RE_INFER.bits |
471 TypeFlags::HAS_CT_INFER.bits |
472 TypeFlags::HAS_RE_PLACEHOLDER.bits |
473 TypeFlags::HAS_RE_EARLY_BOUND.bits |
474 TypeFlags::HAS_FREE_REGIONS.bits |
475 TypeFlags::HAS_TY_ERR.bits |
476 TypeFlags::HAS_PROJECTION.bits |
477 TypeFlags::HAS_TY_CLOSURE.bits |
478 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
479 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
480 TypeFlags::HAS_RE_LATE_BOUND.bits |
481 TypeFlags::HAS_TY_PLACEHOLDER.bits |
482 TypeFlags::HAS_CT_PLACEHOLDER.bits;
486 pub struct TyS<'tcx> {
487 pub sty: TyKind<'tcx>,
488 pub flags: TypeFlags,
490 /// This is a kind of confusing thing: it stores the smallest
493 /// (a) the binder itself captures nothing but
494 /// (b) all the late-bound things within the type are captured
495 /// by some sub-binder.
497 /// So, for a type without any late-bound things, like `u32`, this
498 /// will be *innermost*, because that is the innermost binder that
499 /// captures nothing. But for a type `&'D u32`, where `'D` is a
500 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
501 /// -- the binder itself does not capture `D`, but `D` is captured
502 /// by an inner binder.
504 /// We call this concept an "exclusive" binder `D` because all
505 /// De Bruijn indices within the type are contained within `0..D`
507 outer_exclusive_binder: ty::DebruijnIndex,
510 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
511 #[cfg(target_arch = "x86_64")]
512 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
514 impl<'tcx> Ord for TyS<'tcx> {
515 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
516 self.sty.cmp(&other.sty)
520 impl<'tcx> PartialOrd for TyS<'tcx> {
521 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
522 Some(self.sty.cmp(&other.sty))
526 impl<'tcx> PartialEq for TyS<'tcx> {
528 fn eq(&self, other: &TyS<'tcx>) -> bool {
532 impl<'tcx> Eq for TyS<'tcx> {}
534 impl<'tcx> Hash for TyS<'tcx> {
535 fn hash<H: Hasher>(&self, s: &mut H) {
536 (self as *const TyS<'_>).hash(s)
540 impl<'tcx> TyS<'tcx> {
541 pub fn is_primitive_ty(&self) -> bool {
548 TyKind::Infer(InferTy::IntVar(_)) |
549 TyKind::Infer(InferTy::FloatVar(_)) |
550 TyKind::Infer(InferTy::FreshIntTy(_)) |
551 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
552 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
557 pub fn is_suggestable(&self) -> bool {
562 TyKind::Dynamic(..) |
563 TyKind::Closure(..) |
565 TyKind::Projection(..) => false,
571 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
572 fn hash_stable<W: StableHasherResult>(&self,
573 hcx: &mut StableHashingContext<'a>,
574 hasher: &mut StableHasher<W>) {
578 // The other fields just provide fast access to information that is
579 // also contained in `sty`, so no need to hash them.
582 outer_exclusive_binder: _,
585 sty.hash_stable(hcx, hasher);
589 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
591 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
592 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
594 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
597 /// A dummy type used to force List to by unsized without requiring fat pointers
598 type OpaqueListContents;
601 /// A wrapper for slices with the additional invariant
602 /// that the slice is interned and no other slice with
603 /// the same contents can exist in the same context.
604 /// This means we can use pointer for both
605 /// equality comparisons and hashing.
606 /// Note: `Slice` was already taken by the `Ty`.
611 opaque: OpaqueListContents,
614 unsafe impl<T: Sync> Sync for List<T> {}
616 impl<T: Copy> List<T> {
618 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
619 assert!(!mem::needs_drop::<T>());
620 assert!(mem::size_of::<T>() != 0);
621 assert!(slice.len() != 0);
623 // Align up the size of the len (usize) field
624 let align = mem::align_of::<T>();
625 let align_mask = align - 1;
626 let offset = mem::size_of::<usize>();
627 let offset = (offset + align_mask) & !align_mask;
629 let size = offset + slice.len() * mem::size_of::<T>();
631 let mem = arena.alloc_raw(
633 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
635 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
637 result.len = slice.len();
639 // Write the elements
640 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
641 arena_slice.copy_from_slice(slice);
648 impl<T: fmt::Debug> fmt::Debug for List<T> {
649 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
654 impl<T: Encodable> Encodable for List<T> {
656 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
661 impl<T> Ord for List<T> where T: Ord {
662 fn cmp(&self, other: &List<T>) -> Ordering {
663 if self == other { Ordering::Equal } else {
664 <[T] as Ord>::cmp(&**self, &**other)
669 impl<T> PartialOrd for List<T> where T: PartialOrd {
670 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
671 if self == other { Some(Ordering::Equal) } else {
672 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
677 impl<T: PartialEq> PartialEq for List<T> {
679 fn eq(&self, other: &List<T>) -> bool {
683 impl<T: Eq> Eq for List<T> {}
685 impl<T> Hash for List<T> {
687 fn hash<H: Hasher>(&self, s: &mut H) {
688 (self as *const List<T>).hash(s)
692 impl<T> Deref for List<T> {
695 fn deref(&self) -> &[T] {
697 slice::from_raw_parts(self.data.as_ptr(), self.len)
702 impl<'a, T> IntoIterator for &'a List<T> {
704 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
706 fn into_iter(self) -> Self::IntoIter {
711 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
715 pub fn empty<'a>() -> &'a List<T> {
716 #[repr(align(64), C)]
717 struct EmptySlice([u8; 64]);
718 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
719 assert!(mem::align_of::<T>() <= 64);
721 &*(&EMPTY_SLICE as *const _ as *const List<T>)
726 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
727 pub struct UpvarPath {
728 pub hir_id: hir::HirId,
731 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
732 /// the original var ID (that is, the root variable that is referenced
733 /// by the upvar) and the ID of the closure expression.
734 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
736 pub var_path: UpvarPath,
737 pub closure_expr_id: LocalDefId,
740 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
741 pub enum BorrowKind {
742 /// Data must be immutable and is aliasable.
745 /// Data must be immutable but not aliasable. This kind of borrow
746 /// cannot currently be expressed by the user and is used only in
747 /// implicit closure bindings. It is needed when the closure
748 /// is borrowing or mutating a mutable referent, e.g.:
750 /// let x: &mut isize = ...;
751 /// let y = || *x += 5;
753 /// If we were to try to translate this closure into a more explicit
754 /// form, we'd encounter an error with the code as written:
756 /// struct Env { x: & &mut isize }
757 /// let x: &mut isize = ...;
758 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
759 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
761 /// This is then illegal because you cannot mutate a `&mut` found
762 /// in an aliasable location. To solve, you'd have to translate with
763 /// an `&mut` borrow:
765 /// struct Env { x: & &mut isize }
766 /// let x: &mut isize = ...;
767 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
768 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
770 /// Now the assignment to `**env.x` is legal, but creating a
771 /// mutable pointer to `x` is not because `x` is not mutable. We
772 /// could fix this by declaring `x` as `let mut x`. This is ok in
773 /// user code, if awkward, but extra weird for closures, since the
774 /// borrow is hidden.
776 /// So we introduce a "unique imm" borrow -- the referent is
777 /// immutable, but not aliasable. This solves the problem. For
778 /// simplicity, we don't give users the way to express this
779 /// borrow, it's just used when translating closures.
782 /// Data is mutable and not aliasable.
786 /// Information describing the capture of an upvar. This is computed
787 /// during `typeck`, specifically by `regionck`.
788 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
789 pub enum UpvarCapture<'tcx> {
790 /// Upvar is captured by value. This is always true when the
791 /// closure is labeled `move`, but can also be true in other cases
792 /// depending on inference.
795 /// Upvar is captured by reference.
796 ByRef(UpvarBorrow<'tcx>),
799 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
800 pub struct UpvarBorrow<'tcx> {
801 /// The kind of borrow: by-ref upvars have access to shared
802 /// immutable borrows, which are not part of the normal language
804 pub kind: BorrowKind,
806 /// Region of the resulting reference.
807 pub region: ty::Region<'tcx>,
810 pub type UpvarListMap = FxHashMap<DefId, Vec<UpvarId>>;
811 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
813 #[derive(Copy, Clone)]
814 pub struct ClosureUpvar<'tcx> {
820 #[derive(Clone, Copy, PartialEq, Eq)]
821 pub enum IntVarValue {
823 UintType(ast::UintTy),
826 #[derive(Clone, Copy, PartialEq, Eq)]
827 pub struct FloatVarValue(pub ast::FloatTy);
829 impl ty::EarlyBoundRegion {
830 pub fn to_bound_region(&self) -> ty::BoundRegion {
831 ty::BoundRegion::BrNamed(self.def_id, self.name)
834 /// Does this early bound region have a name? Early bound regions normally
835 /// always have names except when using anonymous lifetimes (`'_`).
836 pub fn has_name(&self) -> bool {
837 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
841 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
842 pub enum GenericParamDefKind {
846 object_lifetime_default: ObjectLifetimeDefault,
847 synthetic: Option<hir::SyntheticTyParamKind>,
852 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
853 pub struct GenericParamDef {
854 pub name: InternedString,
858 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
859 /// on generic parameter `'a`/`T`, asserts data behind the parameter
860 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
861 pub pure_wrt_drop: bool,
863 pub kind: GenericParamDefKind,
866 impl GenericParamDef {
867 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
868 if let GenericParamDefKind::Lifetime = self.kind {
869 ty::EarlyBoundRegion {
875 bug!("cannot convert a non-lifetime parameter def to an early bound region")
879 pub fn to_bound_region(&self) -> ty::BoundRegion {
880 if let GenericParamDefKind::Lifetime = self.kind {
881 self.to_early_bound_region_data().to_bound_region()
883 bug!("cannot convert a non-lifetime parameter def to an early bound region")
889 pub struct GenericParamCount {
890 pub lifetimes: usize,
895 /// Information about the formal type/lifetime parameters associated
896 /// with an item or method. Analogous to `hir::Generics`.
898 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
899 /// `Self` (optionally), `Lifetime` params..., `Type` params...
900 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
901 pub struct Generics {
902 pub parent: Option<DefId>,
903 pub parent_count: usize,
904 pub params: Vec<GenericParamDef>,
906 /// Reverse map to the `index` field of each `GenericParamDef`
907 #[stable_hasher(ignore)]
908 pub param_def_id_to_index: FxHashMap<DefId, u32>,
911 pub has_late_bound_regions: Option<Span>,
914 impl<'a, 'gcx, 'tcx> Generics {
915 pub fn count(&self) -> usize {
916 self.parent_count + self.params.len()
919 pub fn own_counts(&self) -> GenericParamCount {
920 // We could cache this as a property of `GenericParamCount`, but
921 // the aim is to refactor this away entirely eventually and the
922 // presence of this method will be a constant reminder.
923 let mut own_counts: GenericParamCount = Default::default();
925 for param in &self.params {
927 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
928 GenericParamDefKind::Type { .. } => own_counts.types += 1,
929 GenericParamDefKind::Const => own_counts.consts += 1,
936 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
937 if self.own_requires_monomorphization() {
941 if let Some(parent_def_id) = self.parent {
942 let parent = tcx.generics_of(parent_def_id);
943 parent.requires_monomorphization(tcx)
949 pub fn own_requires_monomorphization(&self) -> bool {
950 for param in &self.params {
952 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
953 GenericParamDefKind::Lifetime => {}
959 pub fn region_param(&'tcx self,
960 param: &EarlyBoundRegion,
961 tcx: TyCtxt<'a, 'gcx, 'tcx>)
962 -> &'tcx GenericParamDef
964 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
965 let param = &self.params[index as usize];
967 GenericParamDefKind::Lifetime => param,
968 _ => bug!("expected lifetime parameter, but found another generic parameter")
971 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
972 .region_param(param, tcx)
976 /// Returns the `GenericParamDef` associated with this `ParamTy`.
977 pub fn type_param(&'tcx self,
979 tcx: TyCtxt<'a, 'gcx, 'tcx>)
980 -> &'tcx GenericParamDef {
981 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
982 let param = &self.params[index as usize];
984 GenericParamDefKind::Type { .. } => param,
985 _ => bug!("expected type parameter, but found another generic parameter")
988 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
989 .type_param(param, tcx)
993 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
994 pub fn const_param(&'tcx self,
996 tcx: TyCtxt<'a, 'gcx, 'tcx>)
997 -> &GenericParamDef {
998 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
999 let param = &self.params[index as usize];
1001 GenericParamDefKind::Const => param,
1002 _ => bug!("expected const parameter, but found another generic parameter")
1005 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1006 .const_param(param, tcx)
1011 /// Bounds on generics.
1012 #[derive(Clone, Default, Debug, HashStable)]
1013 pub struct GenericPredicates<'tcx> {
1014 pub parent: Option<DefId>,
1015 pub predicates: Vec<(Predicate<'tcx>, Span)>,
1018 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
1019 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
1021 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
1022 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: SubstsRef<'tcx>)
1023 -> InstantiatedPredicates<'tcx> {
1024 let mut instantiated = InstantiatedPredicates::empty();
1025 self.instantiate_into(tcx, &mut instantiated, substs);
1029 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: SubstsRef<'tcx>)
1030 -> InstantiatedPredicates<'tcx> {
1031 InstantiatedPredicates {
1032 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1036 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1037 instantiated: &mut InstantiatedPredicates<'tcx>,
1038 substs: SubstsRef<'tcx>) {
1039 if let Some(def_id) = self.parent {
1040 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1042 instantiated.predicates.extend(
1043 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1047 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1048 -> InstantiatedPredicates<'tcx> {
1049 let mut instantiated = InstantiatedPredicates::empty();
1050 self.instantiate_identity_into(tcx, &mut instantiated);
1054 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1055 instantiated: &mut InstantiatedPredicates<'tcx>) {
1056 if let Some(def_id) = self.parent {
1057 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1059 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1062 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1063 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1064 -> InstantiatedPredicates<'tcx>
1066 assert_eq!(self.parent, None);
1067 InstantiatedPredicates {
1068 predicates: self.predicates.iter().map(|(pred, _)| {
1069 pred.subst_supertrait(tcx, poly_trait_ref)
1075 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1076 pub enum Predicate<'tcx> {
1077 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1078 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1079 /// would be the type parameters.
1080 Trait(PolyTraitPredicate<'tcx>),
1083 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1086 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1088 /// where `<T as TraitRef>::Name == X`, approximately.
1089 /// See the `ProjectionPredicate` struct for details.
1090 Projection(PolyProjectionPredicate<'tcx>),
1092 /// no syntax: `T` well-formed
1093 WellFormed(Ty<'tcx>),
1095 /// trait must be object-safe
1098 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1099 /// for some substitutions `...` and `T` being a closure type.
1100 /// Satisfied (or refuted) once we know the closure's kind.
1101 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1104 Subtype(PolySubtypePredicate<'tcx>),
1106 /// Constant initializer must evaluate successfully.
1107 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1110 /// The crate outlives map is computed during typeck and contains the
1111 /// outlives of every item in the local crate. You should not use it
1112 /// directly, because to do so will make your pass dependent on the
1113 /// HIR of every item in the local crate. Instead, use
1114 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1116 #[derive(HashStable)]
1117 pub struct CratePredicatesMap<'tcx> {
1118 /// For each struct with outlive bounds, maps to a vector of the
1119 /// predicate of its outlive bounds. If an item has no outlives
1120 /// bounds, it will have no entry.
1121 pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
1124 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1125 fn as_ref(&self) -> &Predicate<'tcx> {
1130 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1131 /// Performs a substitution suitable for going from a
1132 /// poly-trait-ref to supertraits that must hold if that
1133 /// poly-trait-ref holds. This is slightly different from a normal
1134 /// substitution in terms of what happens with bound regions. See
1135 /// lengthy comment below for details.
1136 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1137 trait_ref: &ty::PolyTraitRef<'tcx>)
1138 -> ty::Predicate<'tcx>
1140 // The interaction between HRTB and supertraits is not entirely
1141 // obvious. Let me walk you (and myself) through an example.
1143 // Let's start with an easy case. Consider two traits:
1145 // trait Foo<'a>: Bar<'a,'a> { }
1146 // trait Bar<'b,'c> { }
1148 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1149 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1150 // knew that `Foo<'x>` (for any 'x) then we also know that
1151 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1152 // normal substitution.
1154 // In terms of why this is sound, the idea is that whenever there
1155 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1156 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1157 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1160 // Another example to be careful of is this:
1162 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1163 // trait Bar1<'b,'c> { }
1165 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1166 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1167 // reason is similar to the previous example: any impl of
1168 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1169 // basically we would want to collapse the bound lifetimes from
1170 // the input (`trait_ref`) and the supertraits.
1172 // To achieve this in practice is fairly straightforward. Let's
1173 // consider the more complicated scenario:
1175 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1176 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1177 // where both `'x` and `'b` would have a DB index of 1.
1178 // The substitution from the input trait-ref is therefore going to be
1179 // `'a => 'x` (where `'x` has a DB index of 1).
1180 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1181 // early-bound parameter and `'b' is a late-bound parameter with a
1183 // - If we replace `'a` with `'x` from the input, it too will have
1184 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1185 // just as we wanted.
1187 // There is only one catch. If we just apply the substitution `'a
1188 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1189 // adjust the DB index because we substituting into a binder (it
1190 // tries to be so smart...) resulting in `for<'x> for<'b>
1191 // Bar1<'x,'b>` (we have no syntax for this, so use your
1192 // imagination). Basically the 'x will have DB index of 2 and 'b
1193 // will have DB index of 1. Not quite what we want. So we apply
1194 // the substitution to the *contents* of the trait reference,
1195 // rather than the trait reference itself (put another way, the
1196 // substitution code expects equal binding levels in the values
1197 // from the substitution and the value being substituted into, and
1198 // this trick achieves that).
1200 let substs = &trait_ref.skip_binder().substs;
1202 Predicate::Trait(ref binder) =>
1203 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1204 Predicate::Subtype(ref binder) =>
1205 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1206 Predicate::RegionOutlives(ref binder) =>
1207 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1208 Predicate::TypeOutlives(ref binder) =>
1209 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1210 Predicate::Projection(ref binder) =>
1211 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1212 Predicate::WellFormed(data) =>
1213 Predicate::WellFormed(data.subst(tcx, substs)),
1214 Predicate::ObjectSafe(trait_def_id) =>
1215 Predicate::ObjectSafe(trait_def_id),
1216 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1217 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1218 Predicate::ConstEvaluatable(def_id, const_substs) =>
1219 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1224 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1225 pub struct TraitPredicate<'tcx> {
1226 pub trait_ref: TraitRef<'tcx>
1229 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1231 impl<'tcx> TraitPredicate<'tcx> {
1232 pub fn def_id(&self) -> DefId {
1233 self.trait_ref.def_id
1236 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1237 self.trait_ref.input_types()
1240 pub fn self_ty(&self) -> Ty<'tcx> {
1241 self.trait_ref.self_ty()
1245 impl<'tcx> PolyTraitPredicate<'tcx> {
1246 pub fn def_id(&self) -> DefId {
1247 // ok to skip binder since trait def-id does not care about regions
1248 self.skip_binder().def_id()
1252 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1253 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1254 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1255 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1256 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1258 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1260 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1261 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1263 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1264 pub struct SubtypePredicate<'tcx> {
1265 pub a_is_expected: bool,
1269 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1271 /// This kind of predicate has no *direct* correspondent in the
1272 /// syntax, but it roughly corresponds to the syntactic forms:
1274 /// 1. `T: TraitRef<..., Item = Type>`
1275 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1277 /// In particular, form #1 is "desugared" to the combination of a
1278 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1279 /// predicates. Form #2 is a broader form in that it also permits
1280 /// equality between arbitrary types. Processing an instance of
1281 /// Form #2 eventually yields one of these `ProjectionPredicate`
1282 /// instances to normalize the LHS.
1283 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1284 pub struct ProjectionPredicate<'tcx> {
1285 pub projection_ty: ProjectionTy<'tcx>,
1289 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1291 impl<'tcx> PolyProjectionPredicate<'tcx> {
1292 /// Returns the `DefId` of the associated item being projected.
1293 pub fn item_def_id(&self) -> DefId {
1294 self.skip_binder().projection_ty.item_def_id
1298 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1299 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1300 // `self.0.trait_ref` is permitted to have escaping regions.
1301 // This is because here `self` has a `Binder` and so does our
1302 // return value, so we are preserving the number of binding
1304 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1307 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1308 self.map_bound(|predicate| predicate.ty)
1311 /// The `DefId` of the `TraitItem` for the associated type.
1313 /// Note that this is not the `DefId` of the `TraitRef` containing this
1314 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1315 pub fn projection_def_id(&self) -> DefId {
1316 // okay to skip binder since trait def-id does not care about regions
1317 self.skip_binder().projection_ty.item_def_id
1321 pub trait ToPolyTraitRef<'tcx> {
1322 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1325 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1326 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1327 ty::Binder::dummy(self.clone())
1331 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1332 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1333 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1337 pub trait ToPredicate<'tcx> {
1338 fn to_predicate(&self) -> Predicate<'tcx>;
1341 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1342 fn to_predicate(&self) -> Predicate<'tcx> {
1343 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1344 trait_ref: self.clone()
1349 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1350 fn to_predicate(&self) -> Predicate<'tcx> {
1351 ty::Predicate::Trait(self.to_poly_trait_predicate())
1355 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1356 fn to_predicate(&self) -> Predicate<'tcx> {
1357 Predicate::RegionOutlives(self.clone())
1361 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1362 fn to_predicate(&self) -> Predicate<'tcx> {
1363 Predicate::TypeOutlives(self.clone())
1367 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1368 fn to_predicate(&self) -> Predicate<'tcx> {
1369 Predicate::Projection(self.clone())
1373 // A custom iterator used by Predicate::walk_tys.
1374 enum WalkTysIter<'tcx, I, J, K>
1375 where I: Iterator<Item = Ty<'tcx>>,
1376 J: Iterator<Item = Ty<'tcx>>,
1377 K: Iterator<Item = Ty<'tcx>>
1381 Two(Ty<'tcx>, Ty<'tcx>),
1387 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1388 where I: Iterator<Item = Ty<'tcx>>,
1389 J: Iterator<Item = Ty<'tcx>>,
1390 K: Iterator<Item = Ty<'tcx>>
1392 type Item = Ty<'tcx>;
1394 fn next(&mut self) -> Option<Ty<'tcx>> {
1396 WalkTysIter::None => None,
1397 WalkTysIter::One(item) => {
1398 *self = WalkTysIter::None;
1401 WalkTysIter::Two(item1, item2) => {
1402 *self = WalkTysIter::One(item2);
1405 WalkTysIter::Types(ref mut iter) => {
1408 WalkTysIter::InputTypes(ref mut iter) => {
1411 WalkTysIter::ProjectionTypes(ref mut iter) => {
1418 impl<'tcx> Predicate<'tcx> {
1419 /// Iterates over the types in this predicate. Note that in all
1420 /// cases this is skipping over a binder, so late-bound regions
1421 /// with depth 0 are bound by the predicate.
1422 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1424 ty::Predicate::Trait(ref data) => {
1425 WalkTysIter::InputTypes(data.skip_binder().input_types())
1427 ty::Predicate::Subtype(binder) => {
1428 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1429 WalkTysIter::Two(a, b)
1431 ty::Predicate::TypeOutlives(binder) => {
1432 WalkTysIter::One(binder.skip_binder().0)
1434 ty::Predicate::RegionOutlives(..) => {
1437 ty::Predicate::Projection(ref data) => {
1438 let inner = data.skip_binder();
1439 WalkTysIter::ProjectionTypes(
1440 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1442 ty::Predicate::WellFormed(data) => {
1443 WalkTysIter::One(data)
1445 ty::Predicate::ObjectSafe(_trait_def_id) => {
1448 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1449 WalkTysIter::Types(closure_substs.substs.types())
1451 ty::Predicate::ConstEvaluatable(_, substs) => {
1452 WalkTysIter::Types(substs.types())
1457 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1459 Predicate::Trait(ref t) => {
1460 Some(t.to_poly_trait_ref())
1462 Predicate::Projection(..) |
1463 Predicate::Subtype(..) |
1464 Predicate::RegionOutlives(..) |
1465 Predicate::WellFormed(..) |
1466 Predicate::ObjectSafe(..) |
1467 Predicate::ClosureKind(..) |
1468 Predicate::TypeOutlives(..) |
1469 Predicate::ConstEvaluatable(..) => {
1475 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1477 Predicate::TypeOutlives(data) => {
1480 Predicate::Trait(..) |
1481 Predicate::Projection(..) |
1482 Predicate::Subtype(..) |
1483 Predicate::RegionOutlives(..) |
1484 Predicate::WellFormed(..) |
1485 Predicate::ObjectSafe(..) |
1486 Predicate::ClosureKind(..) |
1487 Predicate::ConstEvaluatable(..) => {
1494 /// Represents the bounds declared on a particular set of type
1495 /// parameters. Should eventually be generalized into a flag list of
1496 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1497 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1498 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1499 /// the `GenericPredicates` are expressed in terms of the bound type
1500 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1501 /// represented a set of bounds for some particular instantiation,
1502 /// meaning that the generic parameters have been substituted with
1507 /// struct Foo<T,U:Bar<T>> { ... }
1509 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1510 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1511 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1512 /// [usize:Bar<isize>]]`.
1513 #[derive(Clone, Debug)]
1514 pub struct InstantiatedPredicates<'tcx> {
1515 pub predicates: Vec<Predicate<'tcx>>,
1518 impl<'tcx> InstantiatedPredicates<'tcx> {
1519 pub fn empty() -> InstantiatedPredicates<'tcx> {
1520 InstantiatedPredicates { predicates: vec![] }
1523 pub fn is_empty(&self) -> bool {
1524 self.predicates.is_empty()
1529 /// "Universes" are used during type- and trait-checking in the
1530 /// presence of `for<..>` binders to control what sets of names are
1531 /// visible. Universes are arranged into a tree: the root universe
1532 /// contains names that are always visible. Each child then adds a new
1533 /// set of names that are visible, in addition to those of its parent.
1534 /// We say that the child universe "extends" the parent universe with
1537 /// To make this more concrete, consider this program:
1541 /// fn bar<T>(x: T) {
1542 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1546 /// The struct name `Foo` is in the root universe U0. But the type
1547 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1548 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1549 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1550 /// region `'a` is in a universe U2 that extends U1, because we can
1551 /// name it inside the fn type but not outside.
1553 /// Universes are used to do type- and trait-checking around these
1554 /// "forall" binders (also called **universal quantification**). The
1555 /// idea is that when, in the body of `bar`, we refer to `T` as a
1556 /// type, we aren't referring to any type in particular, but rather a
1557 /// kind of "fresh" type that is distinct from all other types we have
1558 /// actually declared. This is called a **placeholder** type, and we
1559 /// use universes to talk about this. In other words, a type name in
1560 /// universe 0 always corresponds to some "ground" type that the user
1561 /// declared, but a type name in a non-zero universe is a placeholder
1562 /// type -- an idealized representative of "types in general" that we
1563 /// use for checking generic functions.
1564 pub struct UniverseIndex {
1565 DEBUG_FORMAT = "U{}",
1569 impl_stable_hash_for!(struct UniverseIndex { private });
1571 impl UniverseIndex {
1572 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1574 /// Returns the "next" universe index in order -- this new index
1575 /// is considered to extend all previous universes. This
1576 /// corresponds to entering a `forall` quantifier. So, for
1577 /// example, suppose we have this type in universe `U`:
1580 /// for<'a> fn(&'a u32)
1583 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1584 /// new universe that extends `U` -- in this new universe, we can
1585 /// name the region `'a`, but that region was not nameable from
1586 /// `U` because it was not in scope there.
1587 pub fn next_universe(self) -> UniverseIndex {
1588 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1591 /// Returns `true` if `self` can name a name from `other` -- in other words,
1592 /// if the set of names in `self` is a superset of those in
1593 /// `other` (`self >= other`).
1594 pub fn can_name(self, other: UniverseIndex) -> bool {
1595 self.private >= other.private
1598 /// Returns `true` if `self` cannot name some names from `other` -- in other
1599 /// words, if the set of names in `self` is a strict subset of
1600 /// those in `other` (`self < other`).
1601 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1602 self.private < other.private
1606 /// The "placeholder index" fully defines a placeholder region.
1607 /// Placeholder regions are identified by both a **universe** as well
1608 /// as a "bound-region" within that universe. The `bound_region` is
1609 /// basically a name -- distinct bound regions within the same
1610 /// universe are just two regions with an unknown relationship to one
1612 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1613 pub struct Placeholder<T> {
1614 pub universe: UniverseIndex,
1618 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1619 where T: HashStable<StableHashingContext<'a>>
1621 fn hash_stable<W: StableHasherResult>(
1623 hcx: &mut StableHashingContext<'a>,
1624 hasher: &mut StableHasher<W>
1626 self.universe.hash_stable(hcx, hasher);
1627 self.name.hash_stable(hcx, hasher);
1631 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1633 pub type PlaceholderType = Placeholder<BoundVar>;
1635 pub type PlaceholderConst = Placeholder<BoundVar>;
1637 /// When type checking, we use the `ParamEnv` to track
1638 /// details about the set of where-clauses that are in scope at this
1639 /// particular point.
1640 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1641 pub struct ParamEnv<'tcx> {
1642 /// Obligations that the caller must satisfy. This is basically
1643 /// the set of bounds on the in-scope type parameters, translated
1644 /// into Obligations, and elaborated and normalized.
1645 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1647 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1648 /// want `Reveal::All` -- note that this is always paired with an
1649 /// empty environment. To get that, use `ParamEnv::reveal()`.
1650 pub reveal: traits::Reveal,
1652 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1653 /// register that `def_id` (useful for transitioning to the chalk trait
1655 pub def_id: Option<DefId>,
1658 impl<'tcx> ParamEnv<'tcx> {
1659 /// Construct a trait environment suitable for contexts where
1660 /// there are no where-clauses in scope. Hidden types (like `impl
1661 /// Trait`) are left hidden, so this is suitable for ordinary
1664 pub fn empty() -> Self {
1665 Self::new(List::empty(), Reveal::UserFacing, None)
1668 /// Construct a trait environment with no where-clauses in scope
1669 /// where the values of all `impl Trait` and other hidden types
1670 /// are revealed. This is suitable for monomorphized, post-typeck
1671 /// environments like codegen or doing optimizations.
1673 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1674 /// or invoke `param_env.with_reveal_all()`.
1676 pub fn reveal_all() -> Self {
1677 Self::new(List::empty(), Reveal::All, None)
1680 /// Construct a trait environment with the given set of predicates.
1683 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1685 def_id: Option<DefId>
1687 ty::ParamEnv { caller_bounds, reveal, def_id }
1690 /// Returns a new parameter environment with the same clauses, but
1691 /// which "reveals" the true results of projections in all cases
1692 /// (even for associated types that are specializable). This is
1693 /// the desired behavior during codegen and certain other special
1694 /// contexts; normally though we want to use `Reveal::UserFacing`,
1695 /// which is the default.
1696 pub fn with_reveal_all(self) -> Self {
1697 ty::ParamEnv { reveal: Reveal::All, ..self }
1700 /// Returns this same environment but with no caller bounds.
1701 pub fn without_caller_bounds(self) -> Self {
1702 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1705 /// Creates a suitable environment in which to perform trait
1706 /// queries on the given value. When type-checking, this is simply
1707 /// the pair of the environment plus value. But when reveal is set to
1708 /// All, then if `value` does not reference any type parameters, we will
1709 /// pair it with the empty environment. This improves caching and is generally
1712 /// N.B., we preserve the environment when type-checking because it
1713 /// is possible for the user to have wacky where-clauses like
1714 /// `where Box<u32>: Copy`, which are clearly never
1715 /// satisfiable. We generally want to behave as if they were true,
1716 /// although the surrounding function is never reachable.
1717 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1719 Reveal::UserFacing => {
1727 if value.has_placeholders()
1728 || value.needs_infer()
1729 || value.has_param_types()
1730 || value.has_self_ty()
1738 param_env: self.without_caller_bounds(),
1747 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1748 pub struct ParamEnvAnd<'tcx, T> {
1749 pub param_env: ParamEnv<'tcx>,
1753 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1754 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1755 (self.param_env, self.value)
1759 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1760 where T: HashStable<StableHashingContext<'a>>
1762 fn hash_stable<W: StableHasherResult>(&self,
1763 hcx: &mut StableHashingContext<'a>,
1764 hasher: &mut StableHasher<W>) {
1770 param_env.hash_stable(hcx, hasher);
1771 value.hash_stable(hcx, hasher);
1775 #[derive(Copy, Clone, Debug, HashStable)]
1776 pub struct Destructor {
1777 /// The `DefId` of the destructor method
1782 #[derive(HashStable)]
1783 pub struct AdtFlags: u32 {
1784 const NO_ADT_FLAGS = 0;
1785 /// Indicates whether the ADT is an enum.
1786 const IS_ENUM = 1 << 0;
1787 /// Indicates whether the ADT is a union.
1788 const IS_UNION = 1 << 1;
1789 /// Indicates whether the ADT is a struct.
1790 const IS_STRUCT = 1 << 2;
1791 /// Indicates whether the ADT is a struct and has a constructor.
1792 const HAS_CTOR = 1 << 3;
1793 /// Indicates whether the type is a `PhantomData`.
1794 const IS_PHANTOM_DATA = 1 << 4;
1795 /// Indicates whether the type has a `#[fundamental]` attribute.
1796 const IS_FUNDAMENTAL = 1 << 5;
1797 /// Indicates whether the type is a `Box`.
1798 const IS_BOX = 1 << 6;
1799 /// Indicates whether the type is an `Arc`.
1800 const IS_ARC = 1 << 7;
1801 /// Indicates whether the type is an `Rc`.
1802 const IS_RC = 1 << 8;
1803 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1804 /// (i.e., this flag is never set unless this ADT is an enum).
1805 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1810 #[derive(HashStable)]
1811 pub struct VariantFlags: u32 {
1812 const NO_VARIANT_FLAGS = 0;
1813 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1814 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1818 /// Definition of a variant -- a struct's fields or a enum variant.
1820 pub struct VariantDef {
1821 /// `DefId` that identifies the variant itself.
1822 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1824 /// `DefId` that identifies the variant's constructor.
1825 /// If this variant is a struct variant, then this is `None`.
1826 pub ctor_def_id: Option<DefId>,
1827 /// Variant or struct name.
1829 /// Discriminant of this variant.
1830 pub discr: VariantDiscr,
1831 /// Fields of this variant.
1832 pub fields: Vec<FieldDef>,
1833 /// Type of constructor of variant.
1834 pub ctor_kind: CtorKind,
1835 /// Flags of the variant (e.g. is field list non-exhaustive)?
1836 flags: VariantFlags,
1838 pub recovered: bool,
1841 impl<'a, 'gcx, 'tcx> VariantDef {
1842 /// Creates a new `VariantDef`.
1844 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1845 /// represents an enum variant).
1847 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1848 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1850 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1851 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1852 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1853 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1854 /// built-in trait), and we do not want to load attributes twice.
1856 /// If someone speeds up attribute loading to not be a performance concern, they can
1857 /// remove this hack and use the constructor `DefId` everywhere.
1859 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1861 variant_did: Option<DefId>,
1862 ctor_def_id: Option<DefId>,
1863 discr: VariantDiscr,
1864 fields: Vec<FieldDef>,
1865 ctor_kind: CtorKind,
1871 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1872 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1873 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1876 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1877 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, "non_exhaustive") {
1878 debug!("found non-exhaustive field list for {:?}", parent_did);
1879 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1880 } else if let Some(variant_did) = variant_did {
1881 if tcx.has_attr(variant_did, "non_exhaustive") {
1882 debug!("found non-exhaustive field list for {:?}", variant_did);
1883 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1888 def_id: variant_did.unwrap_or(parent_did),
1899 /// Is this field list non-exhaustive?
1901 pub fn is_field_list_non_exhaustive(&self) -> bool {
1902 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1906 impl_stable_hash_for!(struct VariantDef {
1909 ident -> (ident.name),
1917 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1918 pub enum VariantDiscr {
1919 /// Explicit value for this variant, i.e., `X = 123`.
1920 /// The `DefId` corresponds to the embedded constant.
1923 /// The previous variant's discriminant plus one.
1924 /// For efficiency reasons, the distance from the
1925 /// last `Explicit` discriminant is being stored,
1926 /// or `0` for the first variant, if it has none.
1930 #[derive(Debug, HashStable)]
1931 pub struct FieldDef {
1933 #[stable_hasher(project(name))]
1935 pub vis: Visibility,
1938 /// The definition of an abstract data type -- a struct or enum.
1940 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1942 /// `DefId` of the struct, enum or union item.
1944 /// Variants of the ADT. If this is a struct or enum, then there will be a single variant.
1945 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1946 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1948 /// Repr options provided by the user.
1949 pub repr: ReprOptions,
1952 impl PartialOrd for AdtDef {
1953 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1954 Some(self.cmp(&other))
1958 /// There should be only one AdtDef for each `did`, therefore
1959 /// it is fine to implement `Ord` only based on `did`.
1960 impl Ord for AdtDef {
1961 fn cmp(&self, other: &AdtDef) -> Ordering {
1962 self.did.cmp(&other.did)
1966 impl PartialEq for AdtDef {
1967 // AdtDef are always interned and this is part of TyS equality
1969 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1972 impl Eq for AdtDef {}
1974 impl Hash for AdtDef {
1976 fn hash<H: Hasher>(&self, s: &mut H) {
1977 (self as *const AdtDef).hash(s)
1981 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1982 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1987 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1990 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1991 fn hash_stable<W: StableHasherResult>(&self,
1992 hcx: &mut StableHashingContext<'a>,
1993 hasher: &mut StableHasher<W>) {
1995 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1998 let hash: Fingerprint = CACHE.with(|cache| {
1999 let addr = self as *const AdtDef as usize;
2000 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2008 let mut hasher = StableHasher::new();
2009 did.hash_stable(hcx, &mut hasher);
2010 variants.hash_stable(hcx, &mut hasher);
2011 flags.hash_stable(hcx, &mut hasher);
2012 repr.hash_stable(hcx, &mut hasher);
2018 hash.hash_stable(hcx, hasher);
2022 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2023 pub enum AdtKind { Struct, Union, Enum }
2025 impl Into<DataTypeKind> for AdtKind {
2026 fn into(self) -> DataTypeKind {
2028 AdtKind::Struct => DataTypeKind::Struct,
2029 AdtKind::Union => DataTypeKind::Union,
2030 AdtKind::Enum => DataTypeKind::Enum,
2036 #[derive(RustcEncodable, RustcDecodable, Default)]
2037 pub struct ReprFlags: u8 {
2038 const IS_C = 1 << 0;
2039 const IS_SIMD = 1 << 1;
2040 const IS_TRANSPARENT = 1 << 2;
2041 // Internal only for now. If true, don't reorder fields.
2042 const IS_LINEAR = 1 << 3;
2044 // Any of these flags being set prevent field reordering optimisation.
2045 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2046 ReprFlags::IS_SIMD.bits |
2047 ReprFlags::IS_LINEAR.bits;
2051 impl_stable_hash_for!(struct ReprFlags {
2055 /// Represents the repr options provided by the user,
2056 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2057 pub struct ReprOptions {
2058 pub int: Option<attr::IntType>,
2061 pub flags: ReprFlags,
2064 impl_stable_hash_for!(struct ReprOptions {
2072 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
2073 let mut flags = ReprFlags::empty();
2074 let mut size = None;
2075 let mut max_align = 0;
2076 let mut min_pack = 0;
2077 for attr in tcx.get_attrs(did).iter() {
2078 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2079 flags.insert(match r {
2080 attr::ReprC => ReprFlags::IS_C,
2081 attr::ReprPacked(pack) => {
2082 min_pack = if min_pack > 0 {
2083 cmp::min(pack, min_pack)
2089 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2090 attr::ReprSimd => ReprFlags::IS_SIMD,
2091 attr::ReprInt(i) => {
2095 attr::ReprAlign(align) => {
2096 max_align = cmp::max(align, max_align);
2103 // This is here instead of layout because the choice must make it into metadata.
2104 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2105 flags.insert(ReprFlags::IS_LINEAR);
2107 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2111 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2113 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2115 pub fn packed(&self) -> bool { self.pack > 0 }
2117 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2119 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2121 pub fn discr_type(&self) -> attr::IntType {
2122 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2125 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2126 /// layout" optimizations, such as representing `Foo<&T>` as a
2128 pub fn inhibit_enum_layout_opt(&self) -> bool {
2129 self.c() || self.int.is_some()
2132 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2133 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2134 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2135 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
2139 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2140 pub fn inhibit_union_abi_opt(&self) -> bool {
2146 impl<'a, 'gcx, 'tcx> AdtDef {
2147 /// Creates a new `AdtDef`.
2149 tcx: TyCtxt<'_, '_, '_>,
2152 variants: IndexVec<VariantIdx, VariantDef>,
2155 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2156 let mut flags = AdtFlags::NO_ADT_FLAGS;
2158 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2159 debug!("found non-exhaustive variant list for {:?}", did);
2160 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2163 flags |= match kind {
2164 AdtKind::Enum => AdtFlags::IS_ENUM,
2165 AdtKind::Union => AdtFlags::IS_UNION,
2166 AdtKind::Struct => AdtFlags::IS_STRUCT,
2169 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2170 flags |= AdtFlags::HAS_CTOR;
2173 let attrs = tcx.get_attrs(did);
2174 if attr::contains_name(&attrs, "fundamental") {
2175 flags |= AdtFlags::IS_FUNDAMENTAL;
2177 if Some(did) == tcx.lang_items().phantom_data() {
2178 flags |= AdtFlags::IS_PHANTOM_DATA;
2180 if Some(did) == tcx.lang_items().owned_box() {
2181 flags |= AdtFlags::IS_BOX;
2183 if Some(did) == tcx.lang_items().arc() {
2184 flags |= AdtFlags::IS_ARC;
2186 if Some(did) == tcx.lang_items().rc() {
2187 flags |= AdtFlags::IS_RC;
2198 /// Returns `true` if this is a struct.
2200 pub fn is_struct(&self) -> bool {
2201 self.flags.contains(AdtFlags::IS_STRUCT)
2204 /// Returns `true` if this is a union.
2206 pub fn is_union(&self) -> bool {
2207 self.flags.contains(AdtFlags::IS_UNION)
2210 /// Returns `true` if this is a enum.
2212 pub fn is_enum(&self) -> bool {
2213 self.flags.contains(AdtFlags::IS_ENUM)
2216 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2218 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2219 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2222 /// Returns the kind of the ADT.
2224 pub fn adt_kind(&self) -> AdtKind {
2227 } else if self.is_union() {
2234 /// Returns a description of this abstract data type.
2235 pub fn descr(&self) -> &'static str {
2236 match self.adt_kind() {
2237 AdtKind::Struct => "struct",
2238 AdtKind::Union => "union",
2239 AdtKind::Enum => "enum",
2243 /// Returns a description of a variant of this abstract data type.
2245 pub fn variant_descr(&self) -> &'static str {
2246 match self.adt_kind() {
2247 AdtKind::Struct => "struct",
2248 AdtKind::Union => "union",
2249 AdtKind::Enum => "variant",
2253 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2255 pub fn has_ctor(&self) -> bool {
2256 self.flags.contains(AdtFlags::HAS_CTOR)
2259 /// Returns `true` if this type is `#[fundamental]` for the purposes
2260 /// of coherence checking.
2262 pub fn is_fundamental(&self) -> bool {
2263 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2266 /// Returns `true` if this is `PhantomData<T>`.
2268 pub fn is_phantom_data(&self) -> bool {
2269 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2272 /// Returns `true` if this is `Arc<T>`.
2273 pub fn is_arc(&self) -> bool {
2274 self.flags.contains(AdtFlags::IS_ARC)
2277 /// Returns `true` if this is `Rc<T>`.
2278 pub fn is_rc(&self) -> bool {
2279 self.flags.contains(AdtFlags::IS_RC)
2282 /// Returns `true` if this is Box<T>.
2284 pub fn is_box(&self) -> bool {
2285 self.flags.contains(AdtFlags::IS_BOX)
2288 /// Returns `true` if this type has a destructor.
2289 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2290 self.destructor(tcx).is_some()
2293 /// Asserts this is a struct or union and returns its unique variant.
2294 pub fn non_enum_variant(&self) -> &VariantDef {
2295 assert!(self.is_struct() || self.is_union());
2296 &self.variants[VariantIdx::new(0)]
2300 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2301 tcx.predicates_of(self.did)
2304 /// Returns an iterator over all fields contained
2307 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2308 self.variants.iter().flat_map(|v| v.fields.iter())
2311 pub fn is_payloadfree(&self) -> bool {
2312 !self.variants.is_empty() &&
2313 self.variants.iter().all(|v| v.fields.is_empty())
2316 /// Return a `VariantDef` given a variant id.
2317 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2318 self.variants.iter().find(|v| v.def_id == vid)
2319 .expect("variant_with_id: unknown variant")
2322 /// Return a `VariantDef` given a constructor id.
2323 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2324 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2325 .expect("variant_with_ctor_id: unknown variant")
2328 /// Return the index of `VariantDef` given a variant id.
2329 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2330 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2331 .expect("variant_index_with_id: unknown variant").0
2334 /// Return the index of `VariantDef` given a constructor id.
2335 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2336 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2337 .expect("variant_index_with_ctor_id: unknown variant").0
2340 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2342 Def::Variant(vid) => self.variant_with_id(vid),
2343 Def::Ctor(cid, ..) => self.variant_with_ctor_id(cid),
2344 Def::Struct(..) | Def::Union(..) |
2345 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2346 Def::SelfCtor(..) => self.non_enum_variant(),
2347 _ => bug!("unexpected def {:?} in variant_of_def", def)
2352 pub fn eval_explicit_discr(
2354 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2356 ) -> Option<Discr<'tcx>> {
2357 let param_env = ParamEnv::empty();
2358 let repr_type = self.repr.discr_type();
2359 let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), expr_did);
2360 let instance = ty::Instance::new(expr_did, substs);
2361 let cid = GlobalId {
2365 match tcx.const_eval(param_env.and(cid)) {
2367 // FIXME: Find the right type and use it instead of `val.ty` here
2368 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2369 trace!("discriminants: {} ({:?})", b, repr_type);
2375 info!("invalid enum discriminant: {:#?}", val);
2376 crate::mir::interpret::struct_error(
2377 tcx.at(tcx.def_span(expr_did)),
2378 "constant evaluation of enum discriminant resulted in non-integer",
2383 Err(ErrorHandled::Reported) => {
2384 if !expr_did.is_local() {
2385 span_bug!(tcx.def_span(expr_did),
2386 "variant discriminant evaluation succeeded \
2387 in its crate but failed locally");
2391 Err(ErrorHandled::TooGeneric) => span_bug!(
2392 tcx.def_span(expr_did),
2393 "enum discriminant depends on generic arguments",
2399 pub fn discriminants(
2401 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2402 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2403 let repr_type = self.repr.discr_type();
2404 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2405 let mut prev_discr = None::<Discr<'tcx>>;
2406 self.variants.iter_enumerated().map(move |(i, v)| {
2407 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2408 if let VariantDiscr::Explicit(expr_did) = v.discr {
2409 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2413 prev_discr = Some(discr);
2419 /// Computes the discriminant value used by a specific variant.
2420 /// Unlike `discriminants`, this is (amortized) constant-time,
2421 /// only doing at most one query for evaluating an explicit
2422 /// discriminant (the last one before the requested variant),
2423 /// assuming there are no constant-evaluation errors there.
2424 pub fn discriminant_for_variant(&self,
2425 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2426 variant_index: VariantIdx)
2428 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2429 let explicit_value = val
2430 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2431 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2432 explicit_value.checked_add(tcx, offset as u128).0
2435 /// Yields a `DefId` for the discriminant and an offset to add to it
2436 /// Alternatively, if there is no explicit discriminant, returns the
2437 /// inferred discriminant directly.
2438 pub fn discriminant_def_for_variant(
2440 variant_index: VariantIdx,
2441 ) -> (Option<DefId>, u32) {
2442 let mut explicit_index = variant_index.as_u32();
2445 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2446 ty::VariantDiscr::Relative(0) => {
2450 ty::VariantDiscr::Relative(distance) => {
2451 explicit_index -= distance;
2453 ty::VariantDiscr::Explicit(did) => {
2454 expr_did = Some(did);
2459 (expr_did, variant_index.as_u32() - explicit_index)
2462 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2463 tcx.adt_destructor(self.did)
2466 /// Returns a list of types such that `Self: Sized` if and only
2467 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2469 /// Oddly enough, checking that the sized-constraint is `Sized` is
2470 /// actually more expressive than checking all members:
2471 /// the `Sized` trait is inductive, so an associated type that references
2472 /// `Self` would prevent its containing ADT from being `Sized`.
2474 /// Due to normalization being eager, this applies even if
2475 /// the associated type is behind a pointer (e.g., issue #31299).
2476 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2477 tcx.adt_sized_constraint(self.did).0
2480 fn sized_constraint_for_ty(&self,
2481 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2484 let result = match ty.sty {
2485 Bool | Char | Int(..) | Uint(..) | Float(..) |
2486 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2487 Array(..) | Closure(..) | Generator(..) | Never => {
2496 GeneratorWitness(..) => {
2497 // these are never sized - return the target type
2504 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2508 Adt(adt, substs) => {
2510 let adt_tys = adt.sized_constraint(tcx);
2511 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2514 .map(|ty| ty.subst(tcx, substs))
2515 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2519 Projection(..) | Opaque(..) => {
2520 // must calculate explicitly.
2521 // FIXME: consider special-casing always-Sized projections
2525 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2528 // perf hack: if there is a `T: Sized` bound, then
2529 // we know that `T` is Sized and do not need to check
2532 let sized_trait = match tcx.lang_items().sized_trait() {
2534 _ => return vec![ty]
2536 let sized_predicate = Binder::dummy(TraitRef {
2537 def_id: sized_trait,
2538 substs: tcx.mk_substs_trait(ty, &[])
2540 let predicates = &tcx.predicates_of(self.did).predicates;
2541 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2551 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2555 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2560 impl<'a, 'gcx, 'tcx> FieldDef {
2561 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2562 tcx.type_of(self.did).subst(tcx, subst)
2566 /// Represents the various closure traits in the language. This
2567 /// will determine the type of the environment (`self`, in the
2568 /// desugaring) argument that the closure expects.
2570 /// You can get the environment type of a closure using
2571 /// `tcx.closure_env_ty()`.
2572 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2573 RustcEncodable, RustcDecodable, HashStable)]
2574 pub enum ClosureKind {
2575 // Warning: Ordering is significant here! The ordering is chosen
2576 // because the trait Fn is a subtrait of FnMut and so in turn, and
2577 // hence we order it so that Fn < FnMut < FnOnce.
2583 impl<'a, 'tcx> ClosureKind {
2584 // This is the initial value used when doing upvar inference.
2585 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2587 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2589 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2590 ClosureKind::FnMut => {
2591 tcx.require_lang_item(FnMutTraitLangItem)
2593 ClosureKind::FnOnce => {
2594 tcx.require_lang_item(FnOnceTraitLangItem)
2599 /// Returns `true` if this a type that impls this closure kind
2600 /// must also implement `other`.
2601 pub fn extends(self, other: ty::ClosureKind) -> bool {
2602 match (self, other) {
2603 (ClosureKind::Fn, ClosureKind::Fn) => true,
2604 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2605 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2606 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2607 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2608 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2613 /// Returns the representative scalar type for this closure kind.
2614 /// See `TyS::to_opt_closure_kind` for more details.
2615 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2617 ty::ClosureKind::Fn => tcx.types.i8,
2618 ty::ClosureKind::FnMut => tcx.types.i16,
2619 ty::ClosureKind::FnOnce => tcx.types.i32,
2624 impl<'tcx> TyS<'tcx> {
2625 /// Iterator that walks `self` and any types reachable from
2626 /// `self`, in depth-first order. Note that just walks the types
2627 /// that appear in `self`, it does not descend into the fields of
2628 /// structs or variants. For example:
2631 /// isize => { isize }
2632 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2633 /// [isize] => { [isize], isize }
2635 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2636 TypeWalker::new(self)
2639 /// Iterator that walks the immediate children of `self`. Hence
2640 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2641 /// (but not `i32`, like `walk`).
2642 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2643 walk::walk_shallow(self)
2646 /// Walks `ty` and any types appearing within `ty`, invoking the
2647 /// callback `f` on each type. If the callback returns `false`, then the
2648 /// children of the current type are ignored.
2650 /// Note: prefer `ty.walk()` where possible.
2651 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2652 where F: FnMut(Ty<'tcx>) -> bool
2654 let mut walker = self.walk();
2655 while let Some(ty) = walker.next() {
2657 walker.skip_current_subtree();
2664 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2666 hir::MutMutable => MutBorrow,
2667 hir::MutImmutable => ImmBorrow,
2671 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2672 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2673 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2675 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2677 MutBorrow => hir::MutMutable,
2678 ImmBorrow => hir::MutImmutable,
2680 // We have no type corresponding to a unique imm borrow, so
2681 // use `&mut`. It gives all the capabilities of an `&uniq`
2682 // and hence is a safe "over approximation".
2683 UniqueImmBorrow => hir::MutMutable,
2687 pub fn to_user_str(&self) -> &'static str {
2689 MutBorrow => "mutable",
2690 ImmBorrow => "immutable",
2691 UniqueImmBorrow => "uniquely immutable",
2696 #[derive(Debug, Clone)]
2697 pub enum Attributes<'gcx> {
2698 Owned(Lrc<[ast::Attribute]>),
2699 Borrowed(&'gcx [ast::Attribute])
2702 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2703 type Target = [ast::Attribute];
2705 fn deref(&self) -> &[ast::Attribute] {
2707 &Attributes::Owned(ref data) => &data,
2708 &Attributes::Borrowed(data) => data
2713 #[derive(Debug, PartialEq, Eq)]
2714 pub enum ImplOverlapKind {
2715 /// These impls are always allowed to overlap.
2717 /// These impls are allowed to overlap, but that raises
2718 /// an issue #33140 future-compatibility warning.
2720 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2721 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2723 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2724 /// that difference, making what reduces to the following set of impls:
2728 /// impl Trait for dyn Send + Sync {}
2729 /// impl Trait for dyn Sync + Send {}
2732 /// Obviously, once we made these types be identical, that code causes a coherence
2733 /// error and a fairly big headache for us. However, luckily for us, the trait
2734 /// `Trait` used in this case is basically a marker trait, and therefore having
2735 /// overlapping impls for it is sound.
2737 /// To handle this, we basically regard the trait as a marker trait, with an additional
2738 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2739 /// it has the following restrictions:
2741 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2743 /// 2. The trait-ref of both impls must be equal.
2744 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2746 /// 4. Neither of the impls can have any where-clauses.
2748 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2752 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2753 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2754 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2757 /// Returns an iterator of the `DefId`s for all body-owners in this
2758 /// crate. If you would prefer to iterate over the bodies
2759 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2762 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2766 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2769 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2770 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2771 f(self.hir().body_owner_def_id(body_id))
2775 pub fn expr_span(self, id: NodeId) -> Span {
2776 match self.hir().find(id) {
2777 Some(Node::Expr(e)) => {
2781 bug!("Node id {} is not an expr: {:?}", id, f);
2784 bug!("Node id {} is not present in the node map", id);
2789 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2790 self.associated_items(id)
2791 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2795 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2796 self.associated_items(did).any(|item| {
2797 item.relevant_for_never()
2801 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2802 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2803 match self.hir().get_by_hir_id(hir_id) {
2804 Node::TraitItem(_) | Node::ImplItem(_) => true,
2808 match self.describe_def(def_id).expect("no def for def-id") {
2809 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2814 if is_associated_item {
2815 Some(self.associated_item(def_id))
2821 fn associated_item_from_trait_item_ref(self,
2822 parent_def_id: DefId,
2823 parent_vis: &hir::Visibility,
2824 trait_item_ref: &hir::TraitItemRef)
2826 let def_id = self.hir().local_def_id_from_hir_id(trait_item_ref.id.hir_id);
2827 let (kind, has_self) = match trait_item_ref.kind {
2828 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2829 hir::AssociatedItemKind::Method { has_self } => {
2830 (ty::AssociatedKind::Method, has_self)
2832 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2833 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2837 ident: trait_item_ref.ident,
2839 // Visibility of trait items is inherited from their traits.
2840 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2841 defaultness: trait_item_ref.defaultness,
2843 container: TraitContainer(parent_def_id),
2844 method_has_self_argument: has_self
2848 fn associated_item_from_impl_item_ref(self,
2849 parent_def_id: DefId,
2850 impl_item_ref: &hir::ImplItemRef)
2852 let def_id = self.hir().local_def_id_from_hir_id(impl_item_ref.id.hir_id);
2853 let (kind, has_self) = match impl_item_ref.kind {
2854 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2855 hir::AssociatedItemKind::Method { has_self } => {
2856 (ty::AssociatedKind::Method, has_self)
2858 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2859 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2863 ident: impl_item_ref.ident,
2865 // Visibility of trait impl items doesn't matter.
2866 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2867 defaultness: impl_item_ref.defaultness,
2869 container: ImplContainer(parent_def_id),
2870 method_has_self_argument: has_self
2874 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2875 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2878 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2879 variant.fields.iter().position(|field| {
2880 self.adjust_ident(ident, variant.def_id, hir::DUMMY_HIR_ID).0 == field.ident.modern()
2884 pub fn associated_items(
2887 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2888 // Ideally, we would use `-> impl Iterator` here, but it falls
2889 // afoul of the conservative "capture [restrictions]" we put
2890 // in place, so we use a hand-written iterator.
2892 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2893 AssociatedItemsIterator {
2895 def_ids: self.associated_item_def_ids(def_id),
2900 /// Returns `true` if the impls are the same polarity and the trait either
2901 /// has no items or is annotated #[marker] and prevents item overrides.
2902 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2903 -> Option<ImplOverlapKind>
2905 let is_legit = if self.features().overlapping_marker_traits {
2906 let trait1_is_empty = self.impl_trait_ref(def_id1)
2907 .map_or(false, |trait_ref| {
2908 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2910 let trait2_is_empty = self.impl_trait_ref(def_id2)
2911 .map_or(false, |trait_ref| {
2912 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2914 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2918 let is_marker_impl = |def_id: DefId| -> bool {
2919 let trait_ref = self.impl_trait_ref(def_id);
2920 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2922 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2923 && is_marker_impl(def_id1)
2924 && is_marker_impl(def_id2)
2928 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
2930 Some(ImplOverlapKind::Permitted)
2932 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2933 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2934 if self_ty1 == self_ty2 {
2935 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2937 return Some(ImplOverlapKind::Issue33140);
2939 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2940 def_id1, def_id2, self_ty1, self_ty2);
2945 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2951 /// Returns `ty::VariantDef` if `def` refers to a struct,
2952 /// or variant or their constructors, panics otherwise.
2953 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2955 Def::Variant(did) => {
2956 let enum_did = self.parent(did).unwrap();
2957 self.adt_def(enum_did).variant_with_id(did)
2959 Def::Struct(did) | Def::Union(did) => {
2960 self.adt_def(did).non_enum_variant()
2962 Def::Ctor(variant_ctor_did, CtorOf::Variant, ..) => {
2963 let variant_did = self.parent(variant_ctor_did).unwrap();
2964 let enum_did = self.parent(variant_did).unwrap();
2965 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2967 Def::Ctor(ctor_did, CtorOf::Struct, ..) => {
2968 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2969 self.adt_def(struct_did).non_enum_variant()
2971 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2975 pub fn item_name(self, id: DefId) -> InternedString {
2976 if id.index == CRATE_DEF_INDEX {
2977 self.original_crate_name(id.krate).as_interned_str()
2979 let def_key = self.def_key(id);
2980 match def_key.disambiguated_data.data {
2981 // The name of a constructor is that of its parent.
2982 hir_map::DefPathData::Ctor =>
2983 self.item_name(DefId {
2985 index: def_key.parent.unwrap()
2987 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2988 bug!("item_name: no name for {:?}", self.def_path(id));
2994 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2995 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2999 ty::InstanceDef::Item(did) => {
3000 self.optimized_mir(did)
3002 ty::InstanceDef::VtableShim(..) |
3003 ty::InstanceDef::Intrinsic(..) |
3004 ty::InstanceDef::FnPtrShim(..) |
3005 ty::InstanceDef::Virtual(..) |
3006 ty::InstanceDef::ClosureOnceShim { .. } |
3007 ty::InstanceDef::DropGlue(..) |
3008 ty::InstanceDef::CloneShim(..) => {
3009 self.mir_shims(instance)
3014 /// Gets the attributes of a definition.
3015 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
3016 if let Some(id) = self.hir().as_local_hir_id(did) {
3017 Attributes::Borrowed(self.hir().attrs_by_hir_id(id))
3019 Attributes::Owned(self.item_attrs(did))
3023 /// Determines whether an item is annotated with an attribute.
3024 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
3025 attr::contains_name(&self.get_attrs(did), attr)
3028 /// Returns `true` if this is an `auto trait`.
3029 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3030 self.trait_def(trait_def_id).has_auto_impl
3033 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3034 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3037 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3038 /// If it implements no trait, returns `None`.
3039 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3040 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3043 /// If the given defid describes a method belonging to an impl, returns the
3044 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3045 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3046 let item = if def_id.krate != LOCAL_CRATE {
3047 if let Some(Def::Method(_)) = self.describe_def(def_id) {
3048 Some(self.associated_item(def_id))
3053 self.opt_associated_item(def_id)
3056 item.and_then(|trait_item|
3057 match trait_item.container {
3058 TraitContainer(_) => None,
3059 ImplContainer(def_id) => Some(def_id),
3064 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3065 /// with the name of the crate containing the impl.
3066 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3067 if impl_did.is_local() {
3068 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3069 Ok(self.hir().span_by_hir_id(hir_id))
3071 Err(self.crate_name(impl_did.krate))
3075 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3076 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3077 /// definition's parent/scope to perform comparison.
3078 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3079 self.adjust_ident(use_name, def_parent_def_id, hir::DUMMY_HIR_ID).0 == def_name.modern()
3082 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: hir::HirId) -> (Ident, DefId) {
3083 ident = ident.modern();
3084 let target_expansion = match scope.krate {
3085 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3088 let scope = match ident.span.adjust(target_expansion) {
3089 Some(actual_expansion) =>
3090 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3091 None if block == hir::DUMMY_HIR_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
3092 None => self.hir().get_module_parent_by_hir_id(block),
3098 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
3099 tcx: TyCtxt<'a, 'gcx, 'tcx>,
3100 def_ids: Lrc<Vec<DefId>>,
3104 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
3105 type Item = AssociatedItem;
3107 fn next(&mut self) -> Option<AssociatedItem> {
3108 let def_id = self.def_ids.get(self.next_index)?;
3109 self.next_index += 1;
3110 Some(self.tcx.associated_item(*def_id))
3114 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
3115 pub fn with_freevars<T, F>(self, fid: HirId, f: F) -> T where
3116 F: FnOnce(&[hir::Freevar]) -> T,
3118 let def_id = self.hir().local_def_id_from_hir_id(fid);
3119 match self.freevars(def_id) {
3126 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
3127 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3128 let parent_id = tcx.hir().get_parent_item(id);
3129 let parent_def_id = tcx.hir().local_def_id_from_hir_id(parent_id);
3130 let parent_item = tcx.hir().expect_item_by_hir_id(parent_id);
3131 match parent_item.node {
3132 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3133 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3134 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3136 debug_assert_eq!(assoc_item.def_id, def_id);
3141 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3142 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3143 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3146 debug_assert_eq!(assoc_item.def_id, def_id);
3154 span_bug!(parent_item.span,
3155 "unexpected parent of trait or impl item or item not found: {:?}",
3159 #[derive(Clone, HashStable)]
3160 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3162 /// Calculates the `Sized` constraint.
3164 /// In fact, there are only a few options for the types in the constraint:
3165 /// - an obviously-unsized type
3166 /// - a type parameter or projection whose Sizedness can't be known
3167 /// - a tuple of type parameters or projections, if there are multiple
3169 /// - a Error, if a type contained itself. The representability
3170 /// check should catch this case.
3171 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3173 -> AdtSizedConstraint<'tcx> {
3174 let def = tcx.adt_def(def_id);
3176 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3179 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3182 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3184 AdtSizedConstraint(result)
3187 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3189 -> Lrc<Vec<DefId>> {
3190 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3191 let item = tcx.hir().expect_item_by_hir_id(id);
3192 let vec: Vec<_> = match item.node {
3193 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3194 trait_item_refs.iter()
3195 .map(|trait_item_ref| trait_item_ref.id)
3196 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3199 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3200 impl_item_refs.iter()
3201 .map(|impl_item_ref| impl_item_ref.id)
3202 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3205 hir::ItemKind::TraitAlias(..) => vec![],
3206 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3211 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3212 tcx.hir().span_if_local(def_id).unwrap()
3215 /// If the given `DefId` describes an item belonging to a trait,
3216 /// returns the `DefId` of the trait that the trait item belongs to;
3217 /// otherwise, returns `None`.
3218 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3219 tcx.opt_associated_item(def_id)
3220 .and_then(|associated_item| {
3221 match associated_item.container {
3222 TraitContainer(def_id) => Some(def_id),
3223 ImplContainer(_) => None
3228 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3229 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3230 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3231 if let Node::Item(item) = tcx.hir().get_by_hir_id(hir_id) {
3232 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3233 return exist_ty.impl_trait_fn;
3240 /// See `ParamEnv` struct definition for details.
3241 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3245 // The param_env of an impl Trait type is its defining function's param_env
3246 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3247 return param_env(tcx, parent);
3249 // Compute the bounds on Self and the type parameters.
3251 let InstantiatedPredicates { predicates } =
3252 tcx.predicates_of(def_id).instantiate_identity(tcx);
3254 // Finally, we have to normalize the bounds in the environment, in
3255 // case they contain any associated type projections. This process
3256 // can yield errors if the put in illegal associated types, like
3257 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3258 // report these errors right here; this doesn't actually feel
3259 // right to me, because constructing the environment feels like a
3260 // kind of a "idempotent" action, but I'm not sure where would be
3261 // a better place. In practice, we construct environments for
3262 // every fn once during type checking, and we'll abort if there
3263 // are any errors at that point, so after type checking you can be
3264 // sure that this will succeed without errors anyway.
3266 let unnormalized_env = ty::ParamEnv::new(
3267 tcx.intern_predicates(&predicates),
3268 traits::Reveal::UserFacing,
3269 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3272 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3273 tcx.hir().maybe_body_owned_by_by_hir_id(id).map_or(id, |body| body.hir_id)
3275 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3276 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3279 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3280 crate_num: CrateNum) -> CrateDisambiguator {
3281 assert_eq!(crate_num, LOCAL_CRATE);
3282 tcx.sess.local_crate_disambiguator()
3285 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3286 crate_num: CrateNum) -> Symbol {
3287 assert_eq!(crate_num, LOCAL_CRATE);
3288 tcx.crate_name.clone()
3291 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3292 crate_num: CrateNum)
3294 assert_eq!(crate_num, LOCAL_CRATE);
3295 tcx.hir().crate_hash
3298 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3299 instance_def: InstanceDef<'tcx>)
3301 match instance_def {
3302 InstanceDef::Item(..) |
3303 InstanceDef::DropGlue(..) => {
3304 let mir = tcx.instance_mir(instance_def);
3305 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3307 // Estimate the size of other compiler-generated shims to be 1.
3312 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3314 /// See [`ImplOverlapKind::Issue33140`] for more details.
3315 fn issue33140_self_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3319 debug!("issue33140_self_ty({:?})", def_id);
3321 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3322 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3325 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3327 let is_marker_like =
3328 tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
3329 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3331 // Check whether these impls would be ok for a marker trait.
3332 if !is_marker_like {
3333 debug!("issue33140_self_ty - not marker-like!");
3337 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3338 if trait_ref.substs.len() != 1 {
3339 debug!("issue33140_self_ty - impl has substs!");
3343 let predicates = tcx.predicates_of(def_id);
3344 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3345 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3349 let self_ty = trait_ref.self_ty();
3350 let self_ty_matches = match self_ty.sty {
3351 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3355 if self_ty_matches {
3356 debug!("issue33140_self_ty - MATCHES!");
3359 debug!("issue33140_self_ty - non-matching self type");
3364 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3365 context::provide(providers);
3366 erase_regions::provide(providers);
3367 layout::provide(providers);
3368 util::provide(providers);
3369 constness::provide(providers);
3370 *providers = ty::query::Providers {
3372 associated_item_def_ids,
3373 adt_sized_constraint,
3377 crate_disambiguator,
3378 original_crate_name,
3380 trait_impls_of: trait_def::trait_impls_of_provider,
3381 instance_def_size_estimate,
3387 /// A map for the local crate mapping each type to a vector of its
3388 /// inherent impls. This is not meant to be used outside of coherence;
3389 /// rather, you should request the vector for a specific type via
3390 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3391 /// (constructing this map requires touching the entire crate).
3392 #[derive(Clone, Debug, Default, HashStable)]
3393 pub struct CrateInherentImpls {
3394 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3397 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3398 pub struct SymbolName {
3399 // FIXME: we don't rely on interning or equality here - better have
3400 // this be a `&'tcx str`.
3401 pub name: InternedString
3404 impl_stable_hash_for!(struct self::SymbolName {
3409 pub fn new(name: &str) -> SymbolName {
3411 name: Symbol::intern(name).as_interned_str()
3415 pub fn as_str(&self) -> LocalInternedString {
3420 impl fmt::Display for SymbolName {
3421 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3422 fmt::Display::fmt(&self.name, fmt)
3426 impl fmt::Debug for SymbolName {
3427 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3428 fmt::Display::fmt(&self.name, fmt)