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;
100 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;
459 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
460 TypeFlags::HAS_SELF.bits |
461 TypeFlags::HAS_RE_EARLY_BOUND.bits;
463 /// Flags representing the nominal content of a type,
464 /// computed by FlagsComputation. If you add a new nominal
465 /// flag, it should be added here too.
466 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
467 TypeFlags::HAS_SELF.bits |
468 TypeFlags::HAS_TY_INFER.bits |
469 TypeFlags::HAS_RE_INFER.bits |
470 TypeFlags::HAS_CT_INFER.bits |
471 TypeFlags::HAS_RE_PLACEHOLDER.bits |
472 TypeFlags::HAS_RE_EARLY_BOUND.bits |
473 TypeFlags::HAS_FREE_REGIONS.bits |
474 TypeFlags::HAS_TY_ERR.bits |
475 TypeFlags::HAS_PROJECTION.bits |
476 TypeFlags::HAS_TY_CLOSURE.bits |
477 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
478 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
479 TypeFlags::HAS_RE_LATE_BOUND.bits |
480 TypeFlags::HAS_TY_PLACEHOLDER.bits;
484 pub struct TyS<'tcx> {
485 pub sty: TyKind<'tcx>,
486 pub flags: TypeFlags,
488 /// This is a kind of confusing thing: it stores the smallest
491 /// (a) the binder itself captures nothing but
492 /// (b) all the late-bound things within the type are captured
493 /// by some sub-binder.
495 /// So, for a type without any late-bound things, like `u32`, this
496 /// will be *innermost*, because that is the innermost binder that
497 /// captures nothing. But for a type `&'D u32`, where `'D` is a
498 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
499 /// -- the binder itself does not capture `D`, but `D` is captured
500 /// by an inner binder.
502 /// We call this concept an "exclusive" binder `D` because all
503 /// De Bruijn indices within the type are contained within `0..D`
505 outer_exclusive_binder: ty::DebruijnIndex,
508 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
509 #[cfg(target_arch = "x86_64")]
510 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
512 impl<'tcx> Ord for TyS<'tcx> {
513 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
514 self.sty.cmp(&other.sty)
518 impl<'tcx> PartialOrd for TyS<'tcx> {
519 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
520 Some(self.sty.cmp(&other.sty))
524 impl<'tcx> PartialEq for TyS<'tcx> {
526 fn eq(&self, other: &TyS<'tcx>) -> bool {
530 impl<'tcx> Eq for TyS<'tcx> {}
532 impl<'tcx> Hash for TyS<'tcx> {
533 fn hash<H: Hasher>(&self, s: &mut H) {
534 (self as *const TyS<'_>).hash(s)
538 impl<'tcx> TyS<'tcx> {
539 pub fn is_primitive_ty(&self) -> bool {
546 TyKind::Infer(InferTy::IntVar(_)) |
547 TyKind::Infer(InferTy::FloatVar(_)) |
548 TyKind::Infer(InferTy::FreshIntTy(_)) |
549 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
550 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
555 pub fn is_suggestable(&self) -> bool {
560 TyKind::Dynamic(..) |
561 TyKind::Closure(..) |
563 TyKind::Projection(..) => false,
569 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
570 fn hash_stable<W: StableHasherResult>(&self,
571 hcx: &mut StableHashingContext<'a>,
572 hasher: &mut StableHasher<W>) {
576 // The other fields just provide fast access to information that is
577 // also contained in `sty`, so no need to hash them.
580 outer_exclusive_binder: _,
583 sty.hash_stable(hcx, hasher);
587 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
589 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
590 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
592 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
595 /// A dummy type used to force List to by unsized without requiring fat pointers
596 type OpaqueListContents;
599 /// A wrapper for slices with the additional invariant
600 /// that the slice is interned and no other slice with
601 /// the same contents can exist in the same context.
602 /// This means we can use pointer for both
603 /// equality comparisons and hashing.
604 /// Note: `Slice` was already taken by the `Ty`.
609 opaque: OpaqueListContents,
612 unsafe impl<T: Sync> Sync for List<T> {}
614 impl<T: Copy> List<T> {
616 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
617 assert!(!mem::needs_drop::<T>());
618 assert!(mem::size_of::<T>() != 0);
619 assert!(slice.len() != 0);
621 // Align up the size of the len (usize) field
622 let align = mem::align_of::<T>();
623 let align_mask = align - 1;
624 let offset = mem::size_of::<usize>();
625 let offset = (offset + align_mask) & !align_mask;
627 let size = offset + slice.len() * mem::size_of::<T>();
629 let mem = arena.alloc_raw(
631 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
633 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
635 result.len = slice.len();
637 // Write the elements
638 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
639 arena_slice.copy_from_slice(slice);
646 impl<T: fmt::Debug> fmt::Debug for List<T> {
647 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
652 impl<T: Encodable> Encodable for List<T> {
654 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
659 impl<T> Ord for List<T> where T: Ord {
660 fn cmp(&self, other: &List<T>) -> Ordering {
661 if self == other { Ordering::Equal } else {
662 <[T] as Ord>::cmp(&**self, &**other)
667 impl<T> PartialOrd for List<T> where T: PartialOrd {
668 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
669 if self == other { Some(Ordering::Equal) } else {
670 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
675 impl<T: PartialEq> PartialEq for List<T> {
677 fn eq(&self, other: &List<T>) -> bool {
681 impl<T: Eq> Eq for List<T> {}
683 impl<T> Hash for List<T> {
685 fn hash<H: Hasher>(&self, s: &mut H) {
686 (self as *const List<T>).hash(s)
690 impl<T> Deref for List<T> {
693 fn deref(&self) -> &[T] {
695 slice::from_raw_parts(self.data.as_ptr(), self.len)
700 impl<'a, T> IntoIterator for &'a List<T> {
702 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
704 fn into_iter(self) -> Self::IntoIter {
709 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
713 pub fn empty<'a>() -> &'a List<T> {
714 #[repr(align(64), C)]
715 struct EmptySlice([u8; 64]);
716 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
717 assert!(mem::align_of::<T>() <= 64);
719 &*(&EMPTY_SLICE as *const _ as *const List<T>)
724 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
725 pub struct UpvarPath {
726 pub hir_id: hir::HirId,
729 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
730 /// the original var ID (that is, the root variable that is referenced
731 /// by the upvar) and the ID of the closure expression.
732 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
734 pub var_path: UpvarPath,
735 pub closure_expr_id: LocalDefId,
738 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
739 pub enum BorrowKind {
740 /// Data must be immutable and is aliasable.
743 /// Data must be immutable but not aliasable. This kind of borrow
744 /// cannot currently be expressed by the user and is used only in
745 /// implicit closure bindings. It is needed when the closure
746 /// is borrowing or mutating a mutable referent, e.g.:
748 /// let x: &mut isize = ...;
749 /// let y = || *x += 5;
751 /// If we were to try to translate this closure into a more explicit
752 /// form, we'd encounter an error with the code as written:
754 /// struct Env { x: & &mut isize }
755 /// let x: &mut isize = ...;
756 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
757 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
759 /// This is then illegal because you cannot mutate a `&mut` found
760 /// in an aliasable location. To solve, you'd have to translate with
761 /// an `&mut` borrow:
763 /// struct Env { x: & &mut isize }
764 /// let x: &mut isize = ...;
765 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
766 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
768 /// Now the assignment to `**env.x` is legal, but creating a
769 /// mutable pointer to `x` is not because `x` is not mutable. We
770 /// could fix this by declaring `x` as `let mut x`. This is ok in
771 /// user code, if awkward, but extra weird for closures, since the
772 /// borrow is hidden.
774 /// So we introduce a "unique imm" borrow -- the referent is
775 /// immutable, but not aliasable. This solves the problem. For
776 /// simplicity, we don't give users the way to express this
777 /// borrow, it's just used when translating closures.
780 /// Data is mutable and not aliasable.
784 /// Information describing the capture of an upvar. This is computed
785 /// during `typeck`, specifically by `regionck`.
786 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
787 pub enum UpvarCapture<'tcx> {
788 /// Upvar is captured by value. This is always true when the
789 /// closure is labeled `move`, but can also be true in other cases
790 /// depending on inference.
793 /// Upvar is captured by reference.
794 ByRef(UpvarBorrow<'tcx>),
797 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
798 pub struct UpvarBorrow<'tcx> {
799 /// The kind of borrow: by-ref upvars have access to shared
800 /// immutable borrows, which are not part of the normal language
802 pub kind: BorrowKind,
804 /// Region of the resulting reference.
805 pub region: ty::Region<'tcx>,
808 pub type UpvarListMap = FxHashMap<DefId, Vec<UpvarId>>;
809 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
811 #[derive(Copy, Clone)]
812 pub struct ClosureUpvar<'tcx> {
818 #[derive(Clone, Copy, PartialEq, Eq)]
819 pub enum IntVarValue {
821 UintType(ast::UintTy),
824 #[derive(Clone, Copy, PartialEq, Eq)]
825 pub struct FloatVarValue(pub ast::FloatTy);
827 impl ty::EarlyBoundRegion {
828 pub fn to_bound_region(&self) -> ty::BoundRegion {
829 ty::BoundRegion::BrNamed(self.def_id, self.name)
832 /// Does this early bound region have a name? Early bound regions normally
833 /// always have names except when using anonymous lifetimes (`'_`).
834 pub fn has_name(&self) -> bool {
835 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
839 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
840 pub enum GenericParamDefKind {
844 object_lifetime_default: ObjectLifetimeDefault,
845 synthetic: Option<hir::SyntheticTyParamKind>,
850 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
851 pub struct GenericParamDef {
852 pub name: InternedString,
856 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
857 /// on generic parameter `'a`/`T`, asserts data behind the parameter
858 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
859 pub pure_wrt_drop: bool,
861 pub kind: GenericParamDefKind,
864 impl GenericParamDef {
865 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
866 if let GenericParamDefKind::Lifetime = self.kind {
867 ty::EarlyBoundRegion {
873 bug!("cannot convert a non-lifetime parameter def to an early bound region")
877 pub fn to_bound_region(&self) -> ty::BoundRegion {
878 if let GenericParamDefKind::Lifetime = self.kind {
879 self.to_early_bound_region_data().to_bound_region()
881 bug!("cannot convert a non-lifetime parameter def to an early bound region")
887 pub struct GenericParamCount {
888 pub lifetimes: usize,
893 /// Information about the formal type/lifetime parameters associated
894 /// with an item or method. Analogous to `hir::Generics`.
896 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
897 /// `Self` (optionally), `Lifetime` params..., `Type` params...
898 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
899 pub struct Generics {
900 pub parent: Option<DefId>,
901 pub parent_count: usize,
902 pub params: Vec<GenericParamDef>,
904 /// Reverse map to the `index` field of each `GenericParamDef`
905 #[stable_hasher(ignore)]
906 pub param_def_id_to_index: FxHashMap<DefId, u32>,
909 pub has_late_bound_regions: Option<Span>,
912 impl<'a, 'gcx, 'tcx> Generics {
913 pub fn count(&self) -> usize {
914 self.parent_count + self.params.len()
917 pub fn own_counts(&self) -> GenericParamCount {
918 // We could cache this as a property of `GenericParamCount`, but
919 // the aim is to refactor this away entirely eventually and the
920 // presence of this method will be a constant reminder.
921 let mut own_counts: GenericParamCount = Default::default();
923 for param in &self.params {
925 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
926 GenericParamDefKind::Type { .. } => own_counts.types += 1,
927 GenericParamDefKind::Const => own_counts.consts += 1,
934 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
935 if self.own_requires_monomorphization() {
939 if let Some(parent_def_id) = self.parent {
940 let parent = tcx.generics_of(parent_def_id);
941 parent.requires_monomorphization(tcx)
947 pub fn own_requires_monomorphization(&self) -> bool {
948 for param in &self.params {
950 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
951 GenericParamDefKind::Lifetime => {}
957 pub fn region_param(&'tcx self,
958 param: &EarlyBoundRegion,
959 tcx: TyCtxt<'a, 'gcx, 'tcx>)
960 -> &'tcx GenericParamDef
962 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
963 let param = &self.params[index as usize];
965 GenericParamDefKind::Lifetime => param,
966 _ => bug!("expected lifetime parameter, but found another generic parameter")
969 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
970 .region_param(param, tcx)
974 /// Returns the `GenericParamDef` associated with this `ParamTy`.
975 pub fn type_param(&'tcx self,
977 tcx: TyCtxt<'a, 'gcx, 'tcx>)
978 -> &'tcx GenericParamDef {
979 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
980 let param = &self.params[index as usize];
982 GenericParamDefKind::Type { .. } => param,
983 _ => bug!("expected type parameter, but found another generic parameter")
986 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
987 .type_param(param, tcx)
991 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
992 pub fn const_param(&'tcx self,
994 tcx: TyCtxt<'a, 'gcx, 'tcx>)
995 -> &GenericParamDef {
996 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
997 let param = &self.params[index as usize];
999 GenericParamDefKind::Const => param,
1000 _ => bug!("expected const parameter, but found another generic parameter")
1003 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1004 .const_param(param, tcx)
1009 /// Bounds on generics.
1010 #[derive(Clone, Default, Debug, HashStable)]
1011 pub struct GenericPredicates<'tcx> {
1012 pub parent: Option<DefId>,
1013 pub predicates: Vec<(Predicate<'tcx>, Span)>,
1016 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
1017 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
1019 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
1020 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: SubstsRef<'tcx>)
1021 -> InstantiatedPredicates<'tcx> {
1022 let mut instantiated = InstantiatedPredicates::empty();
1023 self.instantiate_into(tcx, &mut instantiated, substs);
1027 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: SubstsRef<'tcx>)
1028 -> InstantiatedPredicates<'tcx> {
1029 InstantiatedPredicates {
1030 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1034 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1035 instantiated: &mut InstantiatedPredicates<'tcx>,
1036 substs: SubstsRef<'tcx>) {
1037 if let Some(def_id) = self.parent {
1038 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1040 instantiated.predicates.extend(
1041 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1045 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1046 -> InstantiatedPredicates<'tcx> {
1047 let mut instantiated = InstantiatedPredicates::empty();
1048 self.instantiate_identity_into(tcx, &mut instantiated);
1052 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1053 instantiated: &mut InstantiatedPredicates<'tcx>) {
1054 if let Some(def_id) = self.parent {
1055 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1057 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1060 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1061 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1062 -> InstantiatedPredicates<'tcx>
1064 assert_eq!(self.parent, None);
1065 InstantiatedPredicates {
1066 predicates: self.predicates.iter().map(|(pred, _)| {
1067 pred.subst_supertrait(tcx, poly_trait_ref)
1073 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1074 pub enum Predicate<'tcx> {
1075 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1076 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1077 /// would be the type parameters.
1078 Trait(PolyTraitPredicate<'tcx>),
1081 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1084 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1086 /// where `<T as TraitRef>::Name == X`, approximately.
1087 /// See the `ProjectionPredicate` struct for details.
1088 Projection(PolyProjectionPredicate<'tcx>),
1090 /// no syntax: `T` well-formed
1091 WellFormed(Ty<'tcx>),
1093 /// trait must be object-safe
1096 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1097 /// for some substitutions `...` and `T` being a closure type.
1098 /// Satisfied (or refuted) once we know the closure's kind.
1099 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1102 Subtype(PolySubtypePredicate<'tcx>),
1104 /// Constant initializer must evaluate successfully.
1105 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1108 /// The crate outlives map is computed during typeck and contains the
1109 /// outlives of every item in the local crate. You should not use it
1110 /// directly, because to do so will make your pass dependent on the
1111 /// HIR of every item in the local crate. Instead, use
1112 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1114 #[derive(HashStable)]
1115 pub struct CratePredicatesMap<'tcx> {
1116 /// For each struct with outlive bounds, maps to a vector of the
1117 /// predicate of its outlive bounds. If an item has no outlives
1118 /// bounds, it will have no entry.
1119 pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
1122 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1123 fn as_ref(&self) -> &Predicate<'tcx> {
1128 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1129 /// Performs a substitution suitable for going from a
1130 /// poly-trait-ref to supertraits that must hold if that
1131 /// poly-trait-ref holds. This is slightly different from a normal
1132 /// substitution in terms of what happens with bound regions. See
1133 /// lengthy comment below for details.
1134 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1135 trait_ref: &ty::PolyTraitRef<'tcx>)
1136 -> ty::Predicate<'tcx>
1138 // The interaction between HRTB and supertraits is not entirely
1139 // obvious. Let me walk you (and myself) through an example.
1141 // Let's start with an easy case. Consider two traits:
1143 // trait Foo<'a>: Bar<'a,'a> { }
1144 // trait Bar<'b,'c> { }
1146 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1147 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1148 // knew that `Foo<'x>` (for any 'x) then we also know that
1149 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1150 // normal substitution.
1152 // In terms of why this is sound, the idea is that whenever there
1153 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1154 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1155 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1158 // Another example to be careful of is this:
1160 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1161 // trait Bar1<'b,'c> { }
1163 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1164 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1165 // reason is similar to the previous example: any impl of
1166 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1167 // basically we would want to collapse the bound lifetimes from
1168 // the input (`trait_ref`) and the supertraits.
1170 // To achieve this in practice is fairly straightforward. Let's
1171 // consider the more complicated scenario:
1173 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1174 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1175 // where both `'x` and `'b` would have a DB index of 1.
1176 // The substitution from the input trait-ref is therefore going to be
1177 // `'a => 'x` (where `'x` has a DB index of 1).
1178 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1179 // early-bound parameter and `'b' is a late-bound parameter with a
1181 // - If we replace `'a` with `'x` from the input, it too will have
1182 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1183 // just as we wanted.
1185 // There is only one catch. If we just apply the substitution `'a
1186 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1187 // adjust the DB index because we substituting into a binder (it
1188 // tries to be so smart...) resulting in `for<'x> for<'b>
1189 // Bar1<'x,'b>` (we have no syntax for this, so use your
1190 // imagination). Basically the 'x will have DB index of 2 and 'b
1191 // will have DB index of 1. Not quite what we want. So we apply
1192 // the substitution to the *contents* of the trait reference,
1193 // rather than the trait reference itself (put another way, the
1194 // substitution code expects equal binding levels in the values
1195 // from the substitution and the value being substituted into, and
1196 // this trick achieves that).
1198 let substs = &trait_ref.skip_binder().substs;
1200 Predicate::Trait(ref binder) =>
1201 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1202 Predicate::Subtype(ref binder) =>
1203 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1204 Predicate::RegionOutlives(ref binder) =>
1205 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1206 Predicate::TypeOutlives(ref binder) =>
1207 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1208 Predicate::Projection(ref binder) =>
1209 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1210 Predicate::WellFormed(data) =>
1211 Predicate::WellFormed(data.subst(tcx, substs)),
1212 Predicate::ObjectSafe(trait_def_id) =>
1213 Predicate::ObjectSafe(trait_def_id),
1214 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1215 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1216 Predicate::ConstEvaluatable(def_id, const_substs) =>
1217 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1222 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1223 pub struct TraitPredicate<'tcx> {
1224 pub trait_ref: TraitRef<'tcx>
1227 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1229 impl<'tcx> TraitPredicate<'tcx> {
1230 pub fn def_id(&self) -> DefId {
1231 self.trait_ref.def_id
1234 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1235 self.trait_ref.input_types()
1238 pub fn self_ty(&self) -> Ty<'tcx> {
1239 self.trait_ref.self_ty()
1243 impl<'tcx> PolyTraitPredicate<'tcx> {
1244 pub fn def_id(&self) -> DefId {
1245 // ok to skip binder since trait def-id does not care about regions
1246 self.skip_binder().def_id()
1250 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1251 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1252 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1253 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1254 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1256 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1258 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1259 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1261 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1262 pub struct SubtypePredicate<'tcx> {
1263 pub a_is_expected: bool,
1267 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1269 /// This kind of predicate has no *direct* correspondent in the
1270 /// syntax, but it roughly corresponds to the syntactic forms:
1272 /// 1. `T: TraitRef<..., Item = Type>`
1273 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1275 /// In particular, form #1 is "desugared" to the combination of a
1276 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1277 /// predicates. Form #2 is a broader form in that it also permits
1278 /// equality between arbitrary types. Processing an instance of
1279 /// Form #2 eventually yields one of these `ProjectionPredicate`
1280 /// instances to normalize the LHS.
1281 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1282 pub struct ProjectionPredicate<'tcx> {
1283 pub projection_ty: ProjectionTy<'tcx>,
1287 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1289 impl<'tcx> PolyProjectionPredicate<'tcx> {
1290 /// Returns the `DefId` of the associated item being projected.
1291 pub fn item_def_id(&self) -> DefId {
1292 self.skip_binder().projection_ty.item_def_id
1296 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1297 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1298 // `self.0.trait_ref` is permitted to have escaping regions.
1299 // This is because here `self` has a `Binder` and so does our
1300 // return value, so we are preserving the number of binding
1302 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1305 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1306 self.map_bound(|predicate| predicate.ty)
1309 /// The `DefId` of the `TraitItem` for the associated type.
1311 /// Note that this is not the `DefId` of the `TraitRef` containing this
1312 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1313 pub fn projection_def_id(&self) -> DefId {
1314 // okay to skip binder since trait def-id does not care about regions
1315 self.skip_binder().projection_ty.item_def_id
1319 pub trait ToPolyTraitRef<'tcx> {
1320 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1323 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1324 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1325 ty::Binder::dummy(self.clone())
1329 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1330 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1331 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1335 pub trait ToPredicate<'tcx> {
1336 fn to_predicate(&self) -> Predicate<'tcx>;
1339 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1340 fn to_predicate(&self) -> Predicate<'tcx> {
1341 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1342 trait_ref: self.clone()
1347 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1348 fn to_predicate(&self) -> Predicate<'tcx> {
1349 ty::Predicate::Trait(self.to_poly_trait_predicate())
1353 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1354 fn to_predicate(&self) -> Predicate<'tcx> {
1355 Predicate::RegionOutlives(self.clone())
1359 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1360 fn to_predicate(&self) -> Predicate<'tcx> {
1361 Predicate::TypeOutlives(self.clone())
1365 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1366 fn to_predicate(&self) -> Predicate<'tcx> {
1367 Predicate::Projection(self.clone())
1371 // A custom iterator used by Predicate::walk_tys.
1372 enum WalkTysIter<'tcx, I, J, K>
1373 where I: Iterator<Item = Ty<'tcx>>,
1374 J: Iterator<Item = Ty<'tcx>>,
1375 K: Iterator<Item = Ty<'tcx>>
1379 Two(Ty<'tcx>, Ty<'tcx>),
1385 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1386 where I: Iterator<Item = Ty<'tcx>>,
1387 J: Iterator<Item = Ty<'tcx>>,
1388 K: Iterator<Item = Ty<'tcx>>
1390 type Item = Ty<'tcx>;
1392 fn next(&mut self) -> Option<Ty<'tcx>> {
1394 WalkTysIter::None => None,
1395 WalkTysIter::One(item) => {
1396 *self = WalkTysIter::None;
1399 WalkTysIter::Two(item1, item2) => {
1400 *self = WalkTysIter::One(item2);
1403 WalkTysIter::Types(ref mut iter) => {
1406 WalkTysIter::InputTypes(ref mut iter) => {
1409 WalkTysIter::ProjectionTypes(ref mut iter) => {
1416 impl<'tcx> Predicate<'tcx> {
1417 /// Iterates over the types in this predicate. Note that in all
1418 /// cases this is skipping over a binder, so late-bound regions
1419 /// with depth 0 are bound by the predicate.
1420 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1422 ty::Predicate::Trait(ref data) => {
1423 WalkTysIter::InputTypes(data.skip_binder().input_types())
1425 ty::Predicate::Subtype(binder) => {
1426 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1427 WalkTysIter::Two(a, b)
1429 ty::Predicate::TypeOutlives(binder) => {
1430 WalkTysIter::One(binder.skip_binder().0)
1432 ty::Predicate::RegionOutlives(..) => {
1435 ty::Predicate::Projection(ref data) => {
1436 let inner = data.skip_binder();
1437 WalkTysIter::ProjectionTypes(
1438 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1440 ty::Predicate::WellFormed(data) => {
1441 WalkTysIter::One(data)
1443 ty::Predicate::ObjectSafe(_trait_def_id) => {
1446 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1447 WalkTysIter::Types(closure_substs.substs.types())
1449 ty::Predicate::ConstEvaluatable(_, substs) => {
1450 WalkTysIter::Types(substs.types())
1455 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1457 Predicate::Trait(ref t) => {
1458 Some(t.to_poly_trait_ref())
1460 Predicate::Projection(..) |
1461 Predicate::Subtype(..) |
1462 Predicate::RegionOutlives(..) |
1463 Predicate::WellFormed(..) |
1464 Predicate::ObjectSafe(..) |
1465 Predicate::ClosureKind(..) |
1466 Predicate::TypeOutlives(..) |
1467 Predicate::ConstEvaluatable(..) => {
1473 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1475 Predicate::TypeOutlives(data) => {
1478 Predicate::Trait(..) |
1479 Predicate::Projection(..) |
1480 Predicate::Subtype(..) |
1481 Predicate::RegionOutlives(..) |
1482 Predicate::WellFormed(..) |
1483 Predicate::ObjectSafe(..) |
1484 Predicate::ClosureKind(..) |
1485 Predicate::ConstEvaluatable(..) => {
1492 /// Represents the bounds declared on a particular set of type
1493 /// parameters. Should eventually be generalized into a flag list of
1494 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1495 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1496 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1497 /// the `GenericPredicates` are expressed in terms of the bound type
1498 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1499 /// represented a set of bounds for some particular instantiation,
1500 /// meaning that the generic parameters have been substituted with
1505 /// struct Foo<T,U:Bar<T>> { ... }
1507 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1508 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1509 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1510 /// [usize:Bar<isize>]]`.
1511 #[derive(Clone, Debug)]
1512 pub struct InstantiatedPredicates<'tcx> {
1513 pub predicates: Vec<Predicate<'tcx>>,
1516 impl<'tcx> InstantiatedPredicates<'tcx> {
1517 pub fn empty() -> InstantiatedPredicates<'tcx> {
1518 InstantiatedPredicates { predicates: vec![] }
1521 pub fn is_empty(&self) -> bool {
1522 self.predicates.is_empty()
1527 /// "Universes" are used during type- and trait-checking in the
1528 /// presence of `for<..>` binders to control what sets of names are
1529 /// visible. Universes are arranged into a tree: the root universe
1530 /// contains names that are always visible. Each child then adds a new
1531 /// set of names that are visible, in addition to those of its parent.
1532 /// We say that the child universe "extends" the parent universe with
1535 /// To make this more concrete, consider this program:
1539 /// fn bar<T>(x: T) {
1540 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1544 /// The struct name `Foo` is in the root universe U0. But the type
1545 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1546 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1547 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1548 /// region `'a` is in a universe U2 that extends U1, because we can
1549 /// name it inside the fn type but not outside.
1551 /// Universes are used to do type- and trait-checking around these
1552 /// "forall" binders (also called **universal quantification**). The
1553 /// idea is that when, in the body of `bar`, we refer to `T` as a
1554 /// type, we aren't referring to any type in particular, but rather a
1555 /// kind of "fresh" type that is distinct from all other types we have
1556 /// actually declared. This is called a **placeholder** type, and we
1557 /// use universes to talk about this. In other words, a type name in
1558 /// universe 0 always corresponds to some "ground" type that the user
1559 /// declared, but a type name in a non-zero universe is a placeholder
1560 /// type -- an idealized representative of "types in general" that we
1561 /// use for checking generic functions.
1562 pub struct UniverseIndex {
1563 DEBUG_FORMAT = "U{}",
1567 impl_stable_hash_for!(struct UniverseIndex { private });
1569 impl UniverseIndex {
1570 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1572 /// Returns the "next" universe index in order -- this new index
1573 /// is considered to extend all previous universes. This
1574 /// corresponds to entering a `forall` quantifier. So, for
1575 /// example, suppose we have this type in universe `U`:
1578 /// for<'a> fn(&'a u32)
1581 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1582 /// new universe that extends `U` -- in this new universe, we can
1583 /// name the region `'a`, but that region was not nameable from
1584 /// `U` because it was not in scope there.
1585 pub fn next_universe(self) -> UniverseIndex {
1586 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1589 /// Returns `true` if `self` can name a name from `other` -- in other words,
1590 /// if the set of names in `self` is a superset of those in
1591 /// `other` (`self >= other`).
1592 pub fn can_name(self, other: UniverseIndex) -> bool {
1593 self.private >= other.private
1596 /// Returns `true` if `self` cannot name some names from `other` -- in other
1597 /// words, if the set of names in `self` is a strict subset of
1598 /// those in `other` (`self < other`).
1599 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1600 self.private < other.private
1604 /// The "placeholder index" fully defines a placeholder region.
1605 /// Placeholder regions are identified by both a **universe** as well
1606 /// as a "bound-region" within that universe. The `bound_region` is
1607 /// basically a name -- distinct bound regions within the same
1608 /// universe are just two regions with an unknown relationship to one
1610 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1611 pub struct Placeholder<T> {
1612 pub universe: UniverseIndex,
1616 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1617 where T: HashStable<StableHashingContext<'a>>
1619 fn hash_stable<W: StableHasherResult>(
1621 hcx: &mut StableHashingContext<'a>,
1622 hasher: &mut StableHasher<W>
1624 self.universe.hash_stable(hcx, hasher);
1625 self.name.hash_stable(hcx, hasher);
1629 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1631 pub type PlaceholderType = Placeholder<BoundVar>;
1633 /// When type checking, we use the `ParamEnv` to track
1634 /// details about the set of where-clauses that are in scope at this
1635 /// particular point.
1636 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1637 pub struct ParamEnv<'tcx> {
1638 /// Obligations that the caller must satisfy. This is basically
1639 /// the set of bounds on the in-scope type parameters, translated
1640 /// into Obligations, and elaborated and normalized.
1641 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1643 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1644 /// want `Reveal::All` -- note that this is always paired with an
1645 /// empty environment. To get that, use `ParamEnv::reveal()`.
1646 pub reveal: traits::Reveal,
1648 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1649 /// register that `def_id` (useful for transitioning to the chalk trait
1651 pub def_id: Option<DefId>,
1654 impl<'tcx> ParamEnv<'tcx> {
1655 /// Construct a trait environment suitable for contexts where
1656 /// there are no where-clauses in scope. Hidden types (like `impl
1657 /// Trait`) are left hidden, so this is suitable for ordinary
1660 pub fn empty() -> Self {
1661 Self::new(List::empty(), Reveal::UserFacing, None)
1664 /// Construct a trait environment with no where-clauses in scope
1665 /// where the values of all `impl Trait` and other hidden types
1666 /// are revealed. This is suitable for monomorphized, post-typeck
1667 /// environments like codegen or doing optimizations.
1669 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1670 /// or invoke `param_env.with_reveal_all()`.
1672 pub fn reveal_all() -> Self {
1673 Self::new(List::empty(), Reveal::All, None)
1676 /// Construct a trait environment with the given set of predicates.
1679 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1681 def_id: Option<DefId>
1683 ty::ParamEnv { caller_bounds, reveal, def_id }
1686 /// Returns a new parameter environment with the same clauses, but
1687 /// which "reveals" the true results of projections in all cases
1688 /// (even for associated types that are specializable). This is
1689 /// the desired behavior during codegen and certain other special
1690 /// contexts; normally though we want to use `Reveal::UserFacing`,
1691 /// which is the default.
1692 pub fn with_reveal_all(self) -> Self {
1693 ty::ParamEnv { reveal: Reveal::All, ..self }
1696 /// Returns this same environment but with no caller bounds.
1697 pub fn without_caller_bounds(self) -> Self {
1698 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1701 /// Creates a suitable environment in which to perform trait
1702 /// queries on the given value. When type-checking, this is simply
1703 /// the pair of the environment plus value. But when reveal is set to
1704 /// All, then if `value` does not reference any type parameters, we will
1705 /// pair it with the empty environment. This improves caching and is generally
1708 /// N.B., we preserve the environment when type-checking because it
1709 /// is possible for the user to have wacky where-clauses like
1710 /// `where Box<u32>: Copy`, which are clearly never
1711 /// satisfiable. We generally want to behave as if they were true,
1712 /// although the surrounding function is never reachable.
1713 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1715 Reveal::UserFacing => {
1723 if value.has_placeholders()
1724 || value.needs_infer()
1725 || value.has_param_types()
1726 || value.has_self_ty()
1734 param_env: self.without_caller_bounds(),
1743 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1744 pub struct ParamEnvAnd<'tcx, T> {
1745 pub param_env: ParamEnv<'tcx>,
1749 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1750 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1751 (self.param_env, self.value)
1755 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1756 where T: HashStable<StableHashingContext<'a>>
1758 fn hash_stable<W: StableHasherResult>(&self,
1759 hcx: &mut StableHashingContext<'a>,
1760 hasher: &mut StableHasher<W>) {
1766 param_env.hash_stable(hcx, hasher);
1767 value.hash_stable(hcx, hasher);
1771 #[derive(Copy, Clone, Debug, HashStable)]
1772 pub struct Destructor {
1773 /// The `DefId` of the destructor method
1778 #[derive(HashStable)]
1779 pub struct AdtFlags: u32 {
1780 const NO_ADT_FLAGS = 0;
1781 /// Indicates whether the ADT is an enum.
1782 const IS_ENUM = 1 << 0;
1783 /// Indicates whether the ADT is a union.
1784 const IS_UNION = 1 << 1;
1785 /// Indicates whether the ADT is a struct.
1786 const IS_STRUCT = 1 << 2;
1787 /// Indicates whether the ADT is a struct and has a constructor.
1788 const HAS_CTOR = 1 << 3;
1789 /// Indicates whether the type is a `PhantomData`.
1790 const IS_PHANTOM_DATA = 1 << 4;
1791 /// Indicates whether the type has a `#[fundamental]` attribute.
1792 const IS_FUNDAMENTAL = 1 << 5;
1793 /// Indicates whether the type is a `Box`.
1794 const IS_BOX = 1 << 6;
1795 /// Indicates whether the type is an `Arc`.
1796 const IS_ARC = 1 << 7;
1797 /// Indicates whether the type is an `Rc`.
1798 const IS_RC = 1 << 8;
1799 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1800 /// (i.e., this flag is never set unless this ADT is an enum).
1801 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1806 #[derive(HashStable)]
1807 pub struct VariantFlags: u32 {
1808 const NO_VARIANT_FLAGS = 0;
1809 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1810 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1814 /// Definition of a variant -- a struct's fields or a enum variant.
1816 pub struct VariantDef {
1817 /// `DefId` that identifies the variant itself.
1818 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1820 /// `DefId` that identifies the variant's constructor.
1821 /// If this variant is a struct variant, then this is `None`.
1822 pub ctor_def_id: Option<DefId>,
1823 /// Variant or struct name.
1825 /// Discriminant of this variant.
1826 pub discr: VariantDiscr,
1827 /// Fields of this variant.
1828 pub fields: Vec<FieldDef>,
1829 /// Type of constructor of variant.
1830 pub ctor_kind: CtorKind,
1831 /// Flags of the variant (e.g. is field list non-exhaustive)?
1832 flags: VariantFlags,
1834 pub recovered: bool,
1837 impl<'a, 'gcx, 'tcx> VariantDef {
1838 /// Creates a new `VariantDef`.
1840 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1841 /// represents an enum variant).
1843 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1844 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1846 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1847 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1848 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1849 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1850 /// built-in trait), and we do not want to load attributes twice.
1852 /// If someone speeds up attribute loading to not be a performance concern, they can
1853 /// remove this hack and use the constructor `DefId` everywhere.
1855 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1857 variant_did: Option<DefId>,
1858 ctor_def_id: Option<DefId>,
1859 discr: VariantDiscr,
1860 fields: Vec<FieldDef>,
1861 ctor_kind: CtorKind,
1867 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1868 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1869 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1872 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1873 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, "non_exhaustive") {
1874 debug!("found non-exhaustive field list for {:?}", parent_did);
1875 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1876 } else if let Some(variant_did) = variant_did {
1877 if tcx.has_attr(variant_did, "non_exhaustive") {
1878 debug!("found non-exhaustive field list for {:?}", variant_did);
1879 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1884 def_id: variant_did.unwrap_or(parent_did),
1895 /// Is this field list non-exhaustive?
1897 pub fn is_field_list_non_exhaustive(&self) -> bool {
1898 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1902 impl_stable_hash_for!(struct VariantDef {
1905 ident -> (ident.name),
1913 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1914 pub enum VariantDiscr {
1915 /// Explicit value for this variant, i.e., `X = 123`.
1916 /// The `DefId` corresponds to the embedded constant.
1919 /// The previous variant's discriminant plus one.
1920 /// For efficiency reasons, the distance from the
1921 /// last `Explicit` discriminant is being stored,
1922 /// or `0` for the first variant, if it has none.
1926 #[derive(Debug, HashStable)]
1927 pub struct FieldDef {
1929 #[stable_hasher(project(name))]
1931 pub vis: Visibility,
1934 /// The definition of an abstract data type -- a struct or enum.
1936 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1938 /// `DefId` of the struct, enum or union item.
1940 /// Variants of the ADT. If this is a struct or enum, then there will be a single variant.
1941 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1942 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1944 /// Repr options provided by the user.
1945 pub repr: ReprOptions,
1948 impl PartialOrd for AdtDef {
1949 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1950 Some(self.cmp(&other))
1954 /// There should be only one AdtDef for each `did`, therefore
1955 /// it is fine to implement `Ord` only based on `did`.
1956 impl Ord for AdtDef {
1957 fn cmp(&self, other: &AdtDef) -> Ordering {
1958 self.did.cmp(&other.did)
1962 impl PartialEq for AdtDef {
1963 // AdtDef are always interned and this is part of TyS equality
1965 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1968 impl Eq for AdtDef {}
1970 impl Hash for AdtDef {
1972 fn hash<H: Hasher>(&self, s: &mut H) {
1973 (self as *const AdtDef).hash(s)
1977 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1978 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1983 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1986 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1987 fn hash_stable<W: StableHasherResult>(&self,
1988 hcx: &mut StableHashingContext<'a>,
1989 hasher: &mut StableHasher<W>) {
1991 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1994 let hash: Fingerprint = CACHE.with(|cache| {
1995 let addr = self as *const AdtDef as usize;
1996 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2004 let mut hasher = StableHasher::new();
2005 did.hash_stable(hcx, &mut hasher);
2006 variants.hash_stable(hcx, &mut hasher);
2007 flags.hash_stable(hcx, &mut hasher);
2008 repr.hash_stable(hcx, &mut hasher);
2014 hash.hash_stable(hcx, hasher);
2018 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2019 pub enum AdtKind { Struct, Union, Enum }
2021 impl Into<DataTypeKind> for AdtKind {
2022 fn into(self) -> DataTypeKind {
2024 AdtKind::Struct => DataTypeKind::Struct,
2025 AdtKind::Union => DataTypeKind::Union,
2026 AdtKind::Enum => DataTypeKind::Enum,
2032 #[derive(RustcEncodable, RustcDecodable, Default)]
2033 pub struct ReprFlags: u8 {
2034 const IS_C = 1 << 0;
2035 const IS_SIMD = 1 << 1;
2036 const IS_TRANSPARENT = 1 << 2;
2037 // Internal only for now. If true, don't reorder fields.
2038 const IS_LINEAR = 1 << 3;
2040 // Any of these flags being set prevent field reordering optimisation.
2041 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2042 ReprFlags::IS_SIMD.bits |
2043 ReprFlags::IS_LINEAR.bits;
2047 impl_stable_hash_for!(struct ReprFlags {
2051 /// Represents the repr options provided by the user,
2052 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2053 pub struct ReprOptions {
2054 pub int: Option<attr::IntType>,
2057 pub flags: ReprFlags,
2060 impl_stable_hash_for!(struct ReprOptions {
2068 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
2069 let mut flags = ReprFlags::empty();
2070 let mut size = None;
2071 let mut max_align = 0;
2072 let mut min_pack = 0;
2073 for attr in tcx.get_attrs(did).iter() {
2074 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2075 flags.insert(match r {
2076 attr::ReprC => ReprFlags::IS_C,
2077 attr::ReprPacked(pack) => {
2078 min_pack = if min_pack > 0 {
2079 cmp::min(pack, min_pack)
2085 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2086 attr::ReprSimd => ReprFlags::IS_SIMD,
2087 attr::ReprInt(i) => {
2091 attr::ReprAlign(align) => {
2092 max_align = cmp::max(align, max_align);
2099 // This is here instead of layout because the choice must make it into metadata.
2100 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2101 flags.insert(ReprFlags::IS_LINEAR);
2103 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2107 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2109 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2111 pub fn packed(&self) -> bool { self.pack > 0 }
2113 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2115 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2117 pub fn discr_type(&self) -> attr::IntType {
2118 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2121 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2122 /// layout" optimizations, such as representing `Foo<&T>` as a
2124 pub fn inhibit_enum_layout_opt(&self) -> bool {
2125 self.c() || self.int.is_some()
2128 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2129 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2130 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2131 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
2135 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2136 pub fn inhibit_union_abi_opt(&self) -> bool {
2142 impl<'a, 'gcx, 'tcx> AdtDef {
2143 /// Creates a new `AdtDef`.
2145 tcx: TyCtxt<'_, '_, '_>,
2148 variants: IndexVec<VariantIdx, VariantDef>,
2151 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2152 let mut flags = AdtFlags::NO_ADT_FLAGS;
2154 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2155 debug!("found non-exhaustive variant list for {:?}", did);
2156 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2159 flags |= match kind {
2160 AdtKind::Enum => AdtFlags::IS_ENUM,
2161 AdtKind::Union => AdtFlags::IS_UNION,
2162 AdtKind::Struct => AdtFlags::IS_STRUCT,
2165 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2166 flags |= AdtFlags::HAS_CTOR;
2169 let attrs = tcx.get_attrs(did);
2170 if attr::contains_name(&attrs, "fundamental") {
2171 flags |= AdtFlags::IS_FUNDAMENTAL;
2173 if Some(did) == tcx.lang_items().phantom_data() {
2174 flags |= AdtFlags::IS_PHANTOM_DATA;
2176 if Some(did) == tcx.lang_items().owned_box() {
2177 flags |= AdtFlags::IS_BOX;
2179 if Some(did) == tcx.lang_items().arc() {
2180 flags |= AdtFlags::IS_ARC;
2182 if Some(did) == tcx.lang_items().rc() {
2183 flags |= AdtFlags::IS_RC;
2194 /// Returns `true` if this is a struct.
2196 pub fn is_struct(&self) -> bool {
2197 self.flags.contains(AdtFlags::IS_STRUCT)
2200 /// Returns `true` if this is a union.
2202 pub fn is_union(&self) -> bool {
2203 self.flags.contains(AdtFlags::IS_UNION)
2206 /// Returns `true` if this is a enum.
2208 pub fn is_enum(&self) -> bool {
2209 self.flags.contains(AdtFlags::IS_ENUM)
2212 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2214 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2215 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2218 /// Returns the kind of the ADT.
2220 pub fn adt_kind(&self) -> AdtKind {
2223 } else if self.is_union() {
2230 /// Returns a description of this abstract data type.
2231 pub fn descr(&self) -> &'static str {
2232 match self.adt_kind() {
2233 AdtKind::Struct => "struct",
2234 AdtKind::Union => "union",
2235 AdtKind::Enum => "enum",
2239 /// Returns a description of a variant of this abstract data type.
2241 pub fn variant_descr(&self) -> &'static str {
2242 match self.adt_kind() {
2243 AdtKind::Struct => "struct",
2244 AdtKind::Union => "union",
2245 AdtKind::Enum => "variant",
2249 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2251 pub fn has_ctor(&self) -> bool {
2252 self.flags.contains(AdtFlags::HAS_CTOR)
2255 /// Returns `true` if this type is `#[fundamental]` for the purposes
2256 /// of coherence checking.
2258 pub fn is_fundamental(&self) -> bool {
2259 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2262 /// Returns `true` if this is `PhantomData<T>`.
2264 pub fn is_phantom_data(&self) -> bool {
2265 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2268 /// Returns `true` if this is `Arc<T>`.
2269 pub fn is_arc(&self) -> bool {
2270 self.flags.contains(AdtFlags::IS_ARC)
2273 /// Returns `true` if this is `Rc<T>`.
2274 pub fn is_rc(&self) -> bool {
2275 self.flags.contains(AdtFlags::IS_RC)
2278 /// Returns `true` if this is Box<T>.
2280 pub fn is_box(&self) -> bool {
2281 self.flags.contains(AdtFlags::IS_BOX)
2284 /// Returns `true` if this type has a destructor.
2285 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2286 self.destructor(tcx).is_some()
2289 /// Asserts this is a struct or union and returns its unique variant.
2290 pub fn non_enum_variant(&self) -> &VariantDef {
2291 assert!(self.is_struct() || self.is_union());
2292 &self.variants[VariantIdx::new(0)]
2296 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2297 tcx.predicates_of(self.did)
2300 /// Returns an iterator over all fields contained
2303 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2304 self.variants.iter().flat_map(|v| v.fields.iter())
2307 pub fn is_payloadfree(&self) -> bool {
2308 !self.variants.is_empty() &&
2309 self.variants.iter().all(|v| v.fields.is_empty())
2312 /// Return a `VariantDef` given a variant id.
2313 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2314 self.variants.iter().find(|v| v.def_id == vid)
2315 .expect("variant_with_id: unknown variant")
2318 /// Return a `VariantDef` given a constructor id.
2319 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2320 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2321 .expect("variant_with_ctor_id: unknown variant")
2324 /// Return the index of `VariantDef` given a variant id.
2325 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2326 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2327 .expect("variant_index_with_id: unknown variant").0
2330 /// Return the index of `VariantDef` given a constructor id.
2331 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2332 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2333 .expect("variant_index_with_ctor_id: unknown variant").0
2336 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2338 Def::Variant(vid) => self.variant_with_id(vid),
2339 Def::Ctor(cid, ..) => self.variant_with_ctor_id(cid),
2340 Def::Struct(..) | Def::Union(..) |
2341 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2342 Def::SelfCtor(..) => self.non_enum_variant(),
2343 _ => bug!("unexpected def {:?} in variant_of_def", def)
2348 pub fn eval_explicit_discr(
2350 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2352 ) -> Option<Discr<'tcx>> {
2353 let param_env = ParamEnv::empty();
2354 let repr_type = self.repr.discr_type();
2355 let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), expr_did);
2356 let instance = ty::Instance::new(expr_did, substs);
2357 let cid = GlobalId {
2361 match tcx.const_eval(param_env.and(cid)) {
2363 // FIXME: Find the right type and use it instead of `val.ty` here
2364 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2365 trace!("discriminants: {} ({:?})", b, repr_type);
2371 info!("invalid enum discriminant: {:#?}", val);
2372 crate::mir::interpret::struct_error(
2373 tcx.at(tcx.def_span(expr_did)),
2374 "constant evaluation of enum discriminant resulted in non-integer",
2379 Err(ErrorHandled::Reported) => {
2380 if !expr_did.is_local() {
2381 span_bug!(tcx.def_span(expr_did),
2382 "variant discriminant evaluation succeeded \
2383 in its crate but failed locally");
2387 Err(ErrorHandled::TooGeneric) => span_bug!(
2388 tcx.def_span(expr_did),
2389 "enum discriminant depends on generic arguments",
2395 pub fn discriminants(
2397 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2398 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2399 let repr_type = self.repr.discr_type();
2400 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2401 let mut prev_discr = None::<Discr<'tcx>>;
2402 self.variants.iter_enumerated().map(move |(i, v)| {
2403 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2404 if let VariantDiscr::Explicit(expr_did) = v.discr {
2405 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2409 prev_discr = Some(discr);
2415 /// Computes the discriminant value used by a specific variant.
2416 /// Unlike `discriminants`, this is (amortized) constant-time,
2417 /// only doing at most one query for evaluating an explicit
2418 /// discriminant (the last one before the requested variant),
2419 /// assuming there are no constant-evaluation errors there.
2420 pub fn discriminant_for_variant(&self,
2421 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2422 variant_index: VariantIdx)
2424 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2425 let explicit_value = val
2426 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2427 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2428 explicit_value.checked_add(tcx, offset as u128).0
2431 /// Yields a `DefId` for the discriminant and an offset to add to it
2432 /// Alternatively, if there is no explicit discriminant, returns the
2433 /// inferred discriminant directly.
2434 pub fn discriminant_def_for_variant(
2436 variant_index: VariantIdx,
2437 ) -> (Option<DefId>, u32) {
2438 let mut explicit_index = variant_index.as_u32();
2441 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2442 ty::VariantDiscr::Relative(0) => {
2446 ty::VariantDiscr::Relative(distance) => {
2447 explicit_index -= distance;
2449 ty::VariantDiscr::Explicit(did) => {
2450 expr_did = Some(did);
2455 (expr_did, variant_index.as_u32() - explicit_index)
2458 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2459 tcx.adt_destructor(self.did)
2462 /// Returns a list of types such that `Self: Sized` if and only
2463 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2465 /// Oddly enough, checking that the sized-constraint is `Sized` is
2466 /// actually more expressive than checking all members:
2467 /// the `Sized` trait is inductive, so an associated type that references
2468 /// `Self` would prevent its containing ADT from being `Sized`.
2470 /// Due to normalization being eager, this applies even if
2471 /// the associated type is behind a pointer (e.g., issue #31299).
2472 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2473 tcx.adt_sized_constraint(self.did).0
2476 fn sized_constraint_for_ty(&self,
2477 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2480 let result = match ty.sty {
2481 Bool | Char | Int(..) | Uint(..) | Float(..) |
2482 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2483 Array(..) | Closure(..) | Generator(..) | Never => {
2492 GeneratorWitness(..) => {
2493 // these are never sized - return the target type
2500 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2504 Adt(adt, substs) => {
2506 let adt_tys = adt.sized_constraint(tcx);
2507 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2510 .map(|ty| ty.subst(tcx, substs))
2511 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2515 Projection(..) | Opaque(..) => {
2516 // must calculate explicitly.
2517 // FIXME: consider special-casing always-Sized projections
2521 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2524 // perf hack: if there is a `T: Sized` bound, then
2525 // we know that `T` is Sized and do not need to check
2528 let sized_trait = match tcx.lang_items().sized_trait() {
2530 _ => return vec![ty]
2532 let sized_predicate = Binder::dummy(TraitRef {
2533 def_id: sized_trait,
2534 substs: tcx.mk_substs_trait(ty, &[])
2536 let predicates = &tcx.predicates_of(self.did).predicates;
2537 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2547 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2551 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2556 impl<'a, 'gcx, 'tcx> FieldDef {
2557 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2558 tcx.type_of(self.did).subst(tcx, subst)
2562 /// Represents the various closure traits in the language. This
2563 /// will determine the type of the environment (`self`, in the
2564 /// desugaring) argument that the closure expects.
2566 /// You can get the environment type of a closure using
2567 /// `tcx.closure_env_ty()`.
2568 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2569 RustcEncodable, RustcDecodable, HashStable)]
2570 pub enum ClosureKind {
2571 // Warning: Ordering is significant here! The ordering is chosen
2572 // because the trait Fn is a subtrait of FnMut and so in turn, and
2573 // hence we order it so that Fn < FnMut < FnOnce.
2579 impl<'a, 'tcx> ClosureKind {
2580 // This is the initial value used when doing upvar inference.
2581 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2583 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2585 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2586 ClosureKind::FnMut => {
2587 tcx.require_lang_item(FnMutTraitLangItem)
2589 ClosureKind::FnOnce => {
2590 tcx.require_lang_item(FnOnceTraitLangItem)
2595 /// Returns `true` if this a type that impls this closure kind
2596 /// must also implement `other`.
2597 pub fn extends(self, other: ty::ClosureKind) -> bool {
2598 match (self, other) {
2599 (ClosureKind::Fn, ClosureKind::Fn) => true,
2600 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2601 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2602 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2603 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2604 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2609 /// Returns the representative scalar type for this closure kind.
2610 /// See `TyS::to_opt_closure_kind` for more details.
2611 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2613 ty::ClosureKind::Fn => tcx.types.i8,
2614 ty::ClosureKind::FnMut => tcx.types.i16,
2615 ty::ClosureKind::FnOnce => tcx.types.i32,
2620 impl<'tcx> TyS<'tcx> {
2621 /// Iterator that walks `self` and any types reachable from
2622 /// `self`, in depth-first order. Note that just walks the types
2623 /// that appear in `self`, it does not descend into the fields of
2624 /// structs or variants. For example:
2627 /// isize => { isize }
2628 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2629 /// [isize] => { [isize], isize }
2631 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2632 TypeWalker::new(self)
2635 /// Iterator that walks the immediate children of `self`. Hence
2636 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2637 /// (but not `i32`, like `walk`).
2638 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2639 walk::walk_shallow(self)
2642 /// Walks `ty` and any types appearing within `ty`, invoking the
2643 /// callback `f` on each type. If the callback returns `false`, then the
2644 /// children of the current type are ignored.
2646 /// Note: prefer `ty.walk()` where possible.
2647 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2648 where F: FnMut(Ty<'tcx>) -> bool
2650 let mut walker = self.walk();
2651 while let Some(ty) = walker.next() {
2653 walker.skip_current_subtree();
2660 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2662 hir::MutMutable => MutBorrow,
2663 hir::MutImmutable => ImmBorrow,
2667 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2668 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2669 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2671 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2673 MutBorrow => hir::MutMutable,
2674 ImmBorrow => hir::MutImmutable,
2676 // We have no type corresponding to a unique imm borrow, so
2677 // use `&mut`. It gives all the capabilities of an `&uniq`
2678 // and hence is a safe "over approximation".
2679 UniqueImmBorrow => hir::MutMutable,
2683 pub fn to_user_str(&self) -> &'static str {
2685 MutBorrow => "mutable",
2686 ImmBorrow => "immutable",
2687 UniqueImmBorrow => "uniquely immutable",
2692 #[derive(Debug, Clone)]
2693 pub enum Attributes<'gcx> {
2694 Owned(Lrc<[ast::Attribute]>),
2695 Borrowed(&'gcx [ast::Attribute])
2698 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2699 type Target = [ast::Attribute];
2701 fn deref(&self) -> &[ast::Attribute] {
2703 &Attributes::Owned(ref data) => &data,
2704 &Attributes::Borrowed(data) => data
2709 #[derive(Debug, PartialEq, Eq)]
2710 pub enum ImplOverlapKind {
2711 /// These impls are always allowed to overlap.
2713 /// These impls are allowed to overlap, but that raises
2714 /// an issue #33140 future-compatibility warning.
2716 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2717 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2719 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2720 /// that difference, making what reduces to the following set of impls:
2724 /// impl Trait for dyn Send + Sync {}
2725 /// impl Trait for dyn Sync + Send {}
2728 /// Obviously, once we made these types be identical, that code causes a coherence
2729 /// error and a fairly big headache for us. However, luckily for us, the trait
2730 /// `Trait` used in this case is basically a marker trait, and therefore having
2731 /// overlapping impls for it is sound.
2733 /// To handle this, we basically regard the trait as a marker trait, with an additional
2734 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2735 /// it has the following restrictions:
2737 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2739 /// 2. The trait-ref of both impls must be equal.
2740 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2742 /// 4. Neither of the impls can have any where-clauses.
2744 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2748 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2749 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2750 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2753 /// Returns an iterator of the `DefId`s for all body-owners in this
2754 /// crate. If you would prefer to iterate over the bodies
2755 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2758 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2762 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2765 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2766 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2767 f(self.hir().body_owner_def_id(body_id))
2771 pub fn expr_span(self, id: NodeId) -> Span {
2772 match self.hir().find(id) {
2773 Some(Node::Expr(e)) => {
2777 bug!("Node id {} is not an expr: {:?}", id, f);
2780 bug!("Node id {} is not present in the node map", id);
2785 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2786 self.associated_items(id)
2787 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2791 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2792 self.associated_items(did).any(|item| {
2793 item.relevant_for_never()
2797 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2798 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2799 match self.hir().get_by_hir_id(hir_id) {
2800 Node::TraitItem(_) | Node::ImplItem(_) => true,
2804 match self.describe_def(def_id).expect("no def for def-id") {
2805 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2810 if is_associated_item {
2811 Some(self.associated_item(def_id))
2817 fn associated_item_from_trait_item_ref(self,
2818 parent_def_id: DefId,
2819 parent_vis: &hir::Visibility,
2820 trait_item_ref: &hir::TraitItemRef)
2822 let def_id = self.hir().local_def_id_from_hir_id(trait_item_ref.id.hir_id);
2823 let (kind, has_self) = match trait_item_ref.kind {
2824 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2825 hir::AssociatedItemKind::Method { has_self } => {
2826 (ty::AssociatedKind::Method, has_self)
2828 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2829 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2833 ident: trait_item_ref.ident,
2835 // Visibility of trait items is inherited from their traits.
2836 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2837 defaultness: trait_item_ref.defaultness,
2839 container: TraitContainer(parent_def_id),
2840 method_has_self_argument: has_self
2844 fn associated_item_from_impl_item_ref(self,
2845 parent_def_id: DefId,
2846 impl_item_ref: &hir::ImplItemRef)
2848 let def_id = self.hir().local_def_id_from_hir_id(impl_item_ref.id.hir_id);
2849 let (kind, has_self) = match impl_item_ref.kind {
2850 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2851 hir::AssociatedItemKind::Method { has_self } => {
2852 (ty::AssociatedKind::Method, has_self)
2854 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2855 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2859 ident: impl_item_ref.ident,
2861 // Visibility of trait impl items doesn't matter.
2862 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2863 defaultness: impl_item_ref.defaultness,
2865 container: ImplContainer(parent_def_id),
2866 method_has_self_argument: has_self
2870 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2871 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2874 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2875 variant.fields.iter().position(|field| {
2876 self.adjust_ident(ident, variant.def_id, hir::DUMMY_HIR_ID).0 == field.ident.modern()
2880 pub fn associated_items(
2883 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2884 // Ideally, we would use `-> impl Iterator` here, but it falls
2885 // afoul of the conservative "capture [restrictions]" we put
2886 // in place, so we use a hand-written iterator.
2888 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2889 AssociatedItemsIterator {
2891 def_ids: self.associated_item_def_ids(def_id),
2896 /// Returns `true` if the impls are the same polarity and the trait either
2897 /// has no items or is annotated #[marker] and prevents item overrides.
2898 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2899 -> Option<ImplOverlapKind>
2901 let is_legit = if self.features().overlapping_marker_traits {
2902 let trait1_is_empty = self.impl_trait_ref(def_id1)
2903 .map_or(false, |trait_ref| {
2904 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2906 let trait2_is_empty = self.impl_trait_ref(def_id2)
2907 .map_or(false, |trait_ref| {
2908 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2910 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2914 let is_marker_impl = |def_id: DefId| -> bool {
2915 let trait_ref = self.impl_trait_ref(def_id);
2916 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2918 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2919 && is_marker_impl(def_id1)
2920 && is_marker_impl(def_id2)
2924 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
2926 Some(ImplOverlapKind::Permitted)
2928 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2929 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2930 if self_ty1 == self_ty2 {
2931 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2933 return Some(ImplOverlapKind::Issue33140);
2935 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2936 def_id1, def_id2, self_ty1, self_ty2);
2941 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2947 /// Returns `ty::VariantDef` if `def` refers to a struct,
2948 /// or variant or their constructors, panics otherwise.
2949 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2951 Def::Variant(did) => {
2952 let enum_did = self.parent(did).unwrap();
2953 self.adt_def(enum_did).variant_with_id(did)
2955 Def::Struct(did) | Def::Union(did) => {
2956 self.adt_def(did).non_enum_variant()
2958 Def::Ctor(variant_ctor_did, CtorOf::Variant, ..) => {
2959 let variant_did = self.parent(variant_ctor_did).unwrap();
2960 let enum_did = self.parent(variant_did).unwrap();
2961 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2963 Def::Ctor(ctor_did, CtorOf::Struct, ..) => {
2964 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2965 self.adt_def(struct_did).non_enum_variant()
2967 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2971 pub fn item_name(self, id: DefId) -> InternedString {
2972 if id.index == CRATE_DEF_INDEX {
2973 self.original_crate_name(id.krate).as_interned_str()
2975 let def_key = self.def_key(id);
2976 match def_key.disambiguated_data.data {
2977 // The name of a constructor is that of its parent.
2978 hir_map::DefPathData::Ctor =>
2979 self.item_name(DefId {
2981 index: def_key.parent.unwrap()
2983 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2984 bug!("item_name: no name for {:?}", self.def_path(id));
2990 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2991 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2995 ty::InstanceDef::Item(did) => {
2996 self.optimized_mir(did)
2998 ty::InstanceDef::VtableShim(..) |
2999 ty::InstanceDef::Intrinsic(..) |
3000 ty::InstanceDef::FnPtrShim(..) |
3001 ty::InstanceDef::Virtual(..) |
3002 ty::InstanceDef::ClosureOnceShim { .. } |
3003 ty::InstanceDef::DropGlue(..) |
3004 ty::InstanceDef::CloneShim(..) => {
3005 self.mir_shims(instance)
3010 /// Gets the attributes of a definition.
3011 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
3012 if let Some(id) = self.hir().as_local_hir_id(did) {
3013 Attributes::Borrowed(self.hir().attrs_by_hir_id(id))
3015 Attributes::Owned(self.item_attrs(did))
3019 /// Determines whether an item is annotated with an attribute.
3020 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
3021 attr::contains_name(&self.get_attrs(did), attr)
3024 /// Returns `true` if this is an `auto trait`.
3025 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3026 self.trait_def(trait_def_id).has_auto_impl
3029 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3030 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3033 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3034 /// If it implements no trait, returns `None`.
3035 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3036 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3039 /// If the given defid describes a method belonging to an impl, returns the
3040 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3041 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3042 let item = if def_id.krate != LOCAL_CRATE {
3043 if let Some(Def::Method(_)) = self.describe_def(def_id) {
3044 Some(self.associated_item(def_id))
3049 self.opt_associated_item(def_id)
3052 item.and_then(|trait_item|
3053 match trait_item.container {
3054 TraitContainer(_) => None,
3055 ImplContainer(def_id) => Some(def_id),
3060 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3061 /// with the name of the crate containing the impl.
3062 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3063 if impl_did.is_local() {
3064 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3065 Ok(self.hir().span_by_hir_id(hir_id))
3067 Err(self.crate_name(impl_did.krate))
3071 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3072 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3073 /// definition's parent/scope to perform comparison.
3074 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3075 self.adjust_ident(use_name, def_parent_def_id, hir::DUMMY_HIR_ID).0 == def_name.modern()
3078 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: hir::HirId) -> (Ident, DefId) {
3079 ident = ident.modern();
3080 let target_expansion = match scope.krate {
3081 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3084 let scope = match ident.span.adjust(target_expansion) {
3085 Some(actual_expansion) =>
3086 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3087 None if block == hir::DUMMY_HIR_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
3088 None => self.hir().get_module_parent_by_hir_id(block),
3094 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
3095 tcx: TyCtxt<'a, 'gcx, 'tcx>,
3096 def_ids: Lrc<Vec<DefId>>,
3100 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
3101 type Item = AssociatedItem;
3103 fn next(&mut self) -> Option<AssociatedItem> {
3104 let def_id = self.def_ids.get(self.next_index)?;
3105 self.next_index += 1;
3106 Some(self.tcx.associated_item(*def_id))
3110 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
3111 pub fn with_freevars<T, F>(self, fid: HirId, f: F) -> T where
3112 F: FnOnce(&[hir::Freevar]) -> T,
3114 let def_id = self.hir().local_def_id_from_hir_id(fid);
3115 match self.freevars(def_id) {
3122 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
3123 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3124 let parent_id = tcx.hir().get_parent_item(id);
3125 let parent_def_id = tcx.hir().local_def_id_from_hir_id(parent_id);
3126 let parent_item = tcx.hir().expect_item_by_hir_id(parent_id);
3127 match parent_item.node {
3128 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3129 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3130 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3132 debug_assert_eq!(assoc_item.def_id, def_id);
3137 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3138 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3139 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3142 debug_assert_eq!(assoc_item.def_id, def_id);
3150 span_bug!(parent_item.span,
3151 "unexpected parent of trait or impl item or item not found: {:?}",
3155 #[derive(Clone, HashStable)]
3156 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3158 /// Calculates the `Sized` constraint.
3160 /// In fact, there are only a few options for the types in the constraint:
3161 /// - an obviously-unsized type
3162 /// - a type parameter or projection whose Sizedness can't be known
3163 /// - a tuple of type parameters or projections, if there are multiple
3165 /// - a Error, if a type contained itself. The representability
3166 /// check should catch this case.
3167 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3169 -> AdtSizedConstraint<'tcx> {
3170 let def = tcx.adt_def(def_id);
3172 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3175 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3178 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3180 AdtSizedConstraint(result)
3183 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3185 -> Lrc<Vec<DefId>> {
3186 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3187 let item = tcx.hir().expect_item_by_hir_id(id);
3188 let vec: Vec<_> = match item.node {
3189 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3190 trait_item_refs.iter()
3191 .map(|trait_item_ref| trait_item_ref.id)
3192 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3195 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3196 impl_item_refs.iter()
3197 .map(|impl_item_ref| impl_item_ref.id)
3198 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3201 hir::ItemKind::TraitAlias(..) => vec![],
3202 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3207 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3208 tcx.hir().span_if_local(def_id).unwrap()
3211 /// If the given `DefId` describes an item belonging to a trait,
3212 /// returns the `DefId` of the trait that the trait item belongs to;
3213 /// otherwise, returns `None`.
3214 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3215 tcx.opt_associated_item(def_id)
3216 .and_then(|associated_item| {
3217 match associated_item.container {
3218 TraitContainer(def_id) => Some(def_id),
3219 ImplContainer(_) => None
3224 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3225 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3226 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3227 if let Node::Item(item) = tcx.hir().get_by_hir_id(hir_id) {
3228 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3229 return exist_ty.impl_trait_fn;
3236 /// See `ParamEnv` struct definition for details.
3237 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3241 // The param_env of an impl Trait type is its defining function's param_env
3242 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3243 return param_env(tcx, parent);
3245 // Compute the bounds on Self and the type parameters.
3247 let InstantiatedPredicates { predicates } =
3248 tcx.predicates_of(def_id).instantiate_identity(tcx);
3250 // Finally, we have to normalize the bounds in the environment, in
3251 // case they contain any associated type projections. This process
3252 // can yield errors if the put in illegal associated types, like
3253 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3254 // report these errors right here; this doesn't actually feel
3255 // right to me, because constructing the environment feels like a
3256 // kind of a "idempotent" action, but I'm not sure where would be
3257 // a better place. In practice, we construct environments for
3258 // every fn once during type checking, and we'll abort if there
3259 // are any errors at that point, so after type checking you can be
3260 // sure that this will succeed without errors anyway.
3262 let unnormalized_env = ty::ParamEnv::new(
3263 tcx.intern_predicates(&predicates),
3264 traits::Reveal::UserFacing,
3265 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3268 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3269 tcx.hir().maybe_body_owned_by_by_hir_id(id).map_or(id, |body| body.hir_id)
3271 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3272 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3275 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3276 crate_num: CrateNum) -> CrateDisambiguator {
3277 assert_eq!(crate_num, LOCAL_CRATE);
3278 tcx.sess.local_crate_disambiguator()
3281 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3282 crate_num: CrateNum) -> Symbol {
3283 assert_eq!(crate_num, LOCAL_CRATE);
3284 tcx.crate_name.clone()
3287 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3288 crate_num: CrateNum)
3290 assert_eq!(crate_num, LOCAL_CRATE);
3291 tcx.hir().crate_hash
3294 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3295 instance_def: InstanceDef<'tcx>)
3297 match instance_def {
3298 InstanceDef::Item(..) |
3299 InstanceDef::DropGlue(..) => {
3300 let mir = tcx.instance_mir(instance_def);
3301 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3303 // Estimate the size of other compiler-generated shims to be 1.
3308 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3310 /// See [`ImplOverlapKind::Issue33140`] for more details.
3311 fn issue33140_self_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3315 debug!("issue33140_self_ty({:?})", def_id);
3317 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3318 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3321 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3323 let is_marker_like =
3324 tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
3325 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3327 // Check whether these impls would be ok for a marker trait.
3328 if !is_marker_like {
3329 debug!("issue33140_self_ty - not marker-like!");
3333 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3334 if trait_ref.substs.len() != 1 {
3335 debug!("issue33140_self_ty - impl has substs!");
3339 let predicates = tcx.predicates_of(def_id);
3340 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3341 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3345 let self_ty = trait_ref.self_ty();
3346 let self_ty_matches = match self_ty.sty {
3347 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3351 if self_ty_matches {
3352 debug!("issue33140_self_ty - MATCHES!");
3355 debug!("issue33140_self_ty - non-matching self type");
3360 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3361 context::provide(providers);
3362 erase_regions::provide(providers);
3363 layout::provide(providers);
3364 util::provide(providers);
3365 constness::provide(providers);
3366 *providers = ty::query::Providers {
3368 associated_item_def_ids,
3369 adt_sized_constraint,
3373 crate_disambiguator,
3374 original_crate_name,
3376 trait_impls_of: trait_def::trait_impls_of_provider,
3377 instance_def_size_estimate,
3383 /// A map for the local crate mapping each type to a vector of its
3384 /// inherent impls. This is not meant to be used outside of coherence;
3385 /// rather, you should request the vector for a specific type via
3386 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3387 /// (constructing this map requires touching the entire crate).
3388 #[derive(Clone, Debug, Default, HashStable)]
3389 pub struct CrateInherentImpls {
3390 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3393 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3394 pub struct SymbolName {
3395 // FIXME: we don't rely on interning or equality here - better have
3396 // this be a `&'tcx str`.
3397 pub name: InternedString
3400 impl_stable_hash_for!(struct self::SymbolName {
3405 pub fn new(name: &str) -> SymbolName {
3407 name: Symbol::intern(name).as_interned_str()
3411 pub fn as_str(&self) -> LocalInternedString {
3416 impl fmt::Display for SymbolName {
3417 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3418 fmt::Display::fmt(&self.name, fmt)
3422 impl fmt::Debug for SymbolName {
3423 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3424 fmt::Display::fmt(&self.name, fmt)