1 // ignore-tidy-filelength
3 pub use self::Variance::*;
4 pub use self::AssocItemContainer::*;
5 pub use self::BorrowKind::*;
6 pub use self::IntVarValue::*;
7 pub use self::fold::TypeFoldable;
9 use crate::hir::{map as hir_map, GlobMap, TraitMap};
11 use crate::hir::def::{Res, DefKind, CtorOf, CtorKind, ExportMap};
12 use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
13 use rustc_data_structures::svh::Svh;
14 use rustc_macros::HashStable;
15 use crate::ich::Fingerprint;
16 use crate::ich::StableHashingContext;
17 use crate::infer::canonical::Canonical;
18 use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
19 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
21 use crate::mir::interpret::{GlobalId, ErrorHandled};
22 use crate::mir::GeneratorLayout;
23 use crate::session::CrateDisambiguator;
24 use crate::traits::{self, Reveal};
26 use crate::ty::layout::VariantIdx;
27 use crate::ty::subst::{Subst, InternalSubsts, SubstsRef};
28 use crate::ty::util::{IntTypeExt, Discr};
29 use crate::ty::walk::TypeWalker;
30 use crate::util::captures::Captures;
31 use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap};
32 use arena::SyncDroplessArena;
33 use crate::session::DataTypeKind;
35 use serialize::{self, Encodable, Encoder};
36 use std::cell::RefCell;
37 use std::cmp::{self, Ordering};
39 use std::hash::{Hash, Hasher};
41 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
45 use syntax::ast::{self, Name, Ident, NodeId};
47 use syntax::ext::hygiene::Mark;
48 use syntax::symbol::{kw, sym, Symbol, LocalInternedString, InternedString};
52 use rustc_data_structures::fx::FxIndexMap;
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, AllArenas, tls, keep_local};
78 pub use self::context::{Lift, TypeckTables, CtxtInterners, GlobalCtxt};
79 pub use self::context::{
80 UserTypeAnnotationIndex, UserType, CanonicalUserType,
81 CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
84 pub use self::instance::{Instance, InstanceDef};
86 pub use self::trait_def::TraitDef;
88 pub use self::query::queries;
101 pub mod inhabitedness;
117 mod structural_impls;
123 pub struct Resolutions {
124 pub trait_map: TraitMap,
125 pub maybe_unused_trait_imports: NodeSet,
126 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
127 pub export_map: ExportMap<NodeId>,
128 pub glob_map: GlobMap,
129 /// Extern prelude entries. The value is `true` if the entry was introduced
130 /// via `extern crate` item and not `--extern` option or compiler built-in.
131 pub extern_prelude: FxHashMap<Name, bool>,
134 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
135 pub enum AssocItemContainer {
136 TraitContainer(DefId),
137 ImplContainer(DefId),
140 impl AssocItemContainer {
141 /// Asserts that this is the `DefId` of an associated item declared
142 /// in a trait, and returns the trait `DefId`.
143 pub fn assert_trait(&self) -> DefId {
145 TraitContainer(id) => id,
146 _ => bug!("associated item has wrong container type: {:?}", self)
150 pub fn id(&self) -> DefId {
152 TraitContainer(id) => id,
153 ImplContainer(id) => id,
158 /// The "header" of an impl is everything outside the body: a Self type, a trait
159 /// ref (in the case of a trait impl), and a set of predicates (from the
160 /// bounds / where-clauses).
161 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
162 pub struct ImplHeader<'tcx> {
163 pub impl_def_id: DefId,
164 pub self_ty: Ty<'tcx>,
165 pub trait_ref: Option<TraitRef<'tcx>>,
166 pub predicates: Vec<Predicate<'tcx>>,
169 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
170 pub struct AssocItem {
172 #[stable_hasher(project(name))]
176 pub defaultness: hir::Defaultness,
177 pub container: AssocItemContainer,
179 /// Whether this is a method with an explicit self
180 /// as its first argument, allowing method calls.
181 pub method_has_self_argument: bool,
184 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable, HashStable)]
193 pub fn def_kind(&self) -> DefKind {
195 AssocKind::Const => DefKind::AssocConst,
196 AssocKind::Method => DefKind::Method,
197 AssocKind::Type => DefKind::AssocTy,
198 AssocKind::Existential => DefKind::AssocExistential,
202 /// Tests whether the associated item admits a non-trivial implementation
204 pub fn relevant_for_never(&self) -> bool {
206 AssocKind::Existential |
208 AssocKind::Type => true,
209 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
210 AssocKind::Method => !self.method_has_self_argument,
214 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
216 ty::AssocKind::Method => {
217 // We skip the binder here because the binder would deanonymize all
218 // late-bound regions, and we don't want method signatures to show up
219 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
220 // regions just fine, showing `fn(&MyType)`.
221 tcx.fn_sig(self.def_id).skip_binder().to_string()
223 ty::AssocKind::Type => format!("type {};", self.ident),
224 ty::AssocKind::Existential => format!("existential type {};", self.ident),
225 ty::AssocKind::Const => {
226 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
232 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
233 pub enum Visibility {
234 /// Visible everywhere (including in other crates).
236 /// Visible only in the given crate-local module.
238 /// Not visible anywhere in the local crate. This is the visibility of private external items.
242 pub trait DefIdTree: Copy {
243 fn parent(self, id: DefId) -> Option<DefId>;
245 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
246 if descendant.krate != ancestor.krate {
250 while descendant != ancestor {
251 match self.parent(descendant) {
252 Some(parent) => descendant = parent,
253 None => return false,
260 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
261 fn parent(self, id: DefId) -> Option<DefId> {
262 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
267 pub fn from_hir(visibility: &hir::Visibility, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
268 match visibility.node {
269 hir::VisibilityKind::Public => Visibility::Public,
270 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
271 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
272 // If there is no resolution, `resolve` will have already reported an error, so
273 // assume that the visibility is public to avoid reporting more privacy errors.
274 Res::Err => Visibility::Public,
275 def => Visibility::Restricted(def.def_id()),
277 hir::VisibilityKind::Inherited => {
278 Visibility::Restricted(tcx.hir().get_module_parent(id))
283 /// Returns `true` if an item with this visibility is accessible from the given block.
284 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
285 let restriction = match self {
286 // Public items are visible everywhere.
287 Visibility::Public => return true,
288 // Private items from other crates are visible nowhere.
289 Visibility::Invisible => return false,
290 // Restricted items are visible in an arbitrary local module.
291 Visibility::Restricted(other) if other.krate != module.krate => return false,
292 Visibility::Restricted(module) => module,
295 tree.is_descendant_of(module, restriction)
298 /// Returns `true` if this visibility is at least as accessible as the given visibility
299 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
300 let vis_restriction = match vis {
301 Visibility::Public => return self == Visibility::Public,
302 Visibility::Invisible => return true,
303 Visibility::Restricted(module) => module,
306 self.is_accessible_from(vis_restriction, tree)
309 // Returns `true` if this item is visible anywhere in the local crate.
310 pub fn is_visible_locally(self) -> bool {
312 Visibility::Public => true,
313 Visibility::Restricted(def_id) => def_id.is_local(),
314 Visibility::Invisible => false,
319 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash, HashStable)]
321 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
322 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
323 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
324 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
327 /// The crate variances map is computed during typeck and contains the
328 /// variance of every item in the local crate. You should not use it
329 /// directly, because to do so will make your pass dependent on the
330 /// HIR of every item in the local crate. Instead, use
331 /// `tcx.variances_of()` to get the variance for a *particular*
333 #[derive(HashStable)]
334 pub struct CrateVariancesMap<'tcx> {
335 /// For each item with generics, maps to a vector of the variance
336 /// of its generics. If an item has no generics, it will have no
338 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
342 /// `a.xform(b)` combines the variance of a context with the
343 /// variance of a type with the following meaning. If we are in a
344 /// context with variance `a`, and we encounter a type argument in
345 /// a position with variance `b`, then `a.xform(b)` is the new
346 /// variance with which the argument appears.
352 /// Here, the "ambient" variance starts as covariant. `*mut T` is
353 /// invariant with respect to `T`, so the variance in which the
354 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
355 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
356 /// respect to its type argument `T`, and hence the variance of
357 /// the `i32` here is `Invariant.xform(Covariant)`, which results
358 /// (again) in `Invariant`.
362 /// fn(*const Vec<i32>, *mut Vec<i32)
364 /// The ambient variance is covariant. A `fn` type is
365 /// contravariant with respect to its parameters, so the variance
366 /// within which both pointer types appear is
367 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
368 /// T` is covariant with respect to `T`, so the variance within
369 /// which the first `Vec<i32>` appears is
370 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
371 /// is true for its `i32` argument. In the `*mut T` case, the
372 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
373 /// and hence the outermost type is `Invariant` with respect to
374 /// `Vec<i32>` (and its `i32` argument).
376 /// Source: Figure 1 of "Taming the Wildcards:
377 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
378 pub fn xform(self, v: ty::Variance) -> ty::Variance {
380 // Figure 1, column 1.
381 (ty::Covariant, ty::Covariant) => ty::Covariant,
382 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
383 (ty::Covariant, ty::Invariant) => ty::Invariant,
384 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
386 // Figure 1, column 2.
387 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
388 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
389 (ty::Contravariant, ty::Invariant) => ty::Invariant,
390 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
392 // Figure 1, column 3.
393 (ty::Invariant, _) => ty::Invariant,
395 // Figure 1, column 4.
396 (ty::Bivariant, _) => ty::Bivariant,
401 // Contains information needed to resolve types and (in the future) look up
402 // the types of AST nodes.
403 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
404 pub struct CReaderCacheKey {
409 // Flags that we track on types. These flags are propagated upwards
410 // through the type during type construction, so that we can quickly
411 // check whether the type has various kinds of types in it without
412 // recursing over the type itself.
414 pub struct TypeFlags: u32 {
415 const HAS_PARAMS = 1 << 0;
416 const HAS_SELF = 1 << 1;
417 const HAS_TY_INFER = 1 << 2;
418 const HAS_RE_INFER = 1 << 3;
419 const HAS_RE_PLACEHOLDER = 1 << 4;
421 /// Does this have any `ReEarlyBound` regions? Used to
422 /// determine whether substitition is required, since those
423 /// represent regions that are bound in a `ty::Generics` and
424 /// hence may be substituted.
425 const HAS_RE_EARLY_BOUND = 1 << 5;
427 /// Does this have any region that "appears free" in the type?
428 /// Basically anything but `ReLateBound` and `ReErased`.
429 const HAS_FREE_REGIONS = 1 << 6;
431 /// Is an error type reachable?
432 const HAS_TY_ERR = 1 << 7;
433 const HAS_PROJECTION = 1 << 8;
435 // FIXME: Rename this to the actual property since it's used for generators too
436 const HAS_TY_CLOSURE = 1 << 9;
438 /// `true` if there are "names" of types and regions and so forth
439 /// that are local to a particular fn
440 const HAS_FREE_LOCAL_NAMES = 1 << 10;
442 /// Present if the type belongs in a local type context.
443 /// Only set for Infer other than Fresh.
444 const KEEP_IN_LOCAL_TCX = 1 << 11;
446 // Is there a projection that does not involve a bound region?
447 // Currently we can't normalize projections w/ bound regions.
448 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
450 /// Does this have any `ReLateBound` regions? Used to check
451 /// if a global bound is safe to evaluate.
452 const HAS_RE_LATE_BOUND = 1 << 13;
454 const HAS_TY_PLACEHOLDER = 1 << 14;
456 const HAS_CT_INFER = 1 << 15;
457 const HAS_CT_PLACEHOLDER = 1 << 16;
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 |
481 TypeFlags::HAS_CT_PLACEHOLDER.bits;
485 #[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
486 pub struct TyS<'tcx> {
487 pub sty: TyKind<'tcx>,
488 pub flags: TypeFlags,
490 /// This is a kind of confusing thing: it stores the smallest
493 /// (a) the binder itself captures nothing but
494 /// (b) all the late-bound things within the type are captured
495 /// by some sub-binder.
497 /// So, for a type without any late-bound things, like `u32`, this
498 /// will be *innermost*, because that is the innermost binder that
499 /// captures nothing. But for a type `&'D u32`, where `'D` is a
500 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
501 /// -- the binder itself does not capture `D`, but `D` is captured
502 /// by an inner binder.
504 /// We call this concept an "exclusive" binder `D` because all
505 /// De Bruijn indices within the type are contained within `0..D`
507 outer_exclusive_binder: ty::DebruijnIndex,
510 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
511 #[cfg(target_arch = "x86_64")]
512 static_assert_size!(TyS<'_>, 32);
514 impl<'tcx> Ord for TyS<'tcx> {
515 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
516 self.sty.cmp(&other.sty)
520 impl<'tcx> PartialOrd for TyS<'tcx> {
521 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
522 Some(self.sty.cmp(&other.sty))
526 impl<'tcx> PartialEq for TyS<'tcx> {
528 fn eq(&self, other: &TyS<'tcx>) -> bool {
532 impl<'tcx> Eq for TyS<'tcx> {}
534 impl<'tcx> Hash for TyS<'tcx> {
535 fn hash<H: Hasher>(&self, s: &mut H) {
536 (self as *const TyS<'_>).hash(s)
540 impl<'tcx> TyS<'tcx> {
541 pub fn is_primitive_ty(&self) -> bool {
548 Infer(InferTy::IntVar(_)) |
549 Infer(InferTy::FloatVar(_)) |
550 Infer(InferTy::FreshIntTy(_)) |
551 Infer(InferTy::FreshFloatTy(_)) => true,
552 Ref(_, x, _) => x.is_primitive_ty(),
557 pub fn is_suggestable(&self) -> bool {
565 Projection(..) => false,
571 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
572 fn hash_stable<W: StableHasherResult>(&self,
573 hcx: &mut StableHashingContext<'a>,
574 hasher: &mut StableHasher<W>) {
578 // The other fields just provide fast access to information that is
579 // also contained in `sty`, so no need to hash them.
582 outer_exclusive_binder: _,
585 sty.hash_stable(hcx, hasher);
589 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
591 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
592 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
594 pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
597 /// A dummy type used to force List to by unsized without requiring fat pointers
598 type OpaqueListContents;
601 /// A wrapper for slices with the additional invariant
602 /// that the slice is interned and no other slice with
603 /// the same contents can exist in the same context.
604 /// This means we can use pointer for both
605 /// equality comparisons and hashing.
606 /// Note: `Slice` was already taken by the `Ty`.
611 opaque: OpaqueListContents,
614 unsafe impl<T: Sync> Sync for List<T> {}
616 impl<T: Copy> List<T> {
618 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
619 assert!(!mem::needs_drop::<T>());
620 assert!(mem::size_of::<T>() != 0);
621 assert!(slice.len() != 0);
623 // Align up the size of the len (usize) field
624 let align = mem::align_of::<T>();
625 let align_mask = align - 1;
626 let offset = mem::size_of::<usize>();
627 let offset = (offset + align_mask) & !align_mask;
629 let size = offset + slice.len() * mem::size_of::<T>();
631 let mem = arena.alloc_raw(
633 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
635 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
637 result.len = slice.len();
639 // Write the elements
640 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
641 arena_slice.copy_from_slice(slice);
648 impl<T: fmt::Debug> fmt::Debug for List<T> {
649 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
654 impl<T: Encodable> Encodable for List<T> {
656 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
661 impl<T> Ord for List<T> where T: Ord {
662 fn cmp(&self, other: &List<T>) -> Ordering {
663 if self == other { Ordering::Equal } else {
664 <[T] as Ord>::cmp(&**self, &**other)
669 impl<T> PartialOrd for List<T> where T: PartialOrd {
670 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
671 if self == other { Some(Ordering::Equal) } else {
672 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
677 impl<T: PartialEq> PartialEq for List<T> {
679 fn eq(&self, other: &List<T>) -> bool {
683 impl<T: Eq> Eq for List<T> {}
685 impl<T> Hash for List<T> {
687 fn hash<H: Hasher>(&self, s: &mut H) {
688 (self as *const List<T>).hash(s)
692 impl<T> Deref for List<T> {
695 fn deref(&self) -> &[T] {
697 slice::from_raw_parts(self.data.as_ptr(), self.len)
702 impl<'a, T> IntoIterator for &'a List<T> {
704 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
706 fn into_iter(self) -> Self::IntoIter {
711 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
715 pub fn empty<'a>() -> &'a List<T> {
716 #[repr(align(64), C)]
717 struct EmptySlice([u8; 64]);
718 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
719 assert!(mem::align_of::<T>() <= 64);
721 &*(&EMPTY_SLICE as *const _ as *const List<T>)
726 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
727 pub struct UpvarPath {
728 pub hir_id: hir::HirId,
731 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
732 /// the original var ID (that is, the root variable that is referenced
733 /// by the upvar) and the ID of the closure expression.
734 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
736 pub var_path: UpvarPath,
737 pub closure_expr_id: LocalDefId,
740 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
741 pub enum BorrowKind {
742 /// Data must be immutable and is aliasable.
745 /// Data must be immutable but not aliasable. This kind of borrow
746 /// cannot currently be expressed by the user and is used only in
747 /// implicit closure bindings. It is needed when the closure
748 /// is borrowing or mutating a mutable referent, e.g.:
750 /// let x: &mut isize = ...;
751 /// let y = || *x += 5;
753 /// If we were to try to translate this closure into a more explicit
754 /// form, we'd encounter an error with the code as written:
756 /// struct Env { x: & &mut isize }
757 /// let x: &mut isize = ...;
758 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
759 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
761 /// This is then illegal because you cannot mutate a `&mut` found
762 /// in an aliasable location. To solve, you'd have to translate with
763 /// an `&mut` borrow:
765 /// struct Env { x: & &mut isize }
766 /// let x: &mut isize = ...;
767 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
768 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
770 /// Now the assignment to `**env.x` is legal, but creating a
771 /// mutable pointer to `x` is not because `x` is not mutable. We
772 /// could fix this by declaring `x` as `let mut x`. This is ok in
773 /// user code, if awkward, but extra weird for closures, since the
774 /// borrow is hidden.
776 /// So we introduce a "unique imm" borrow -- the referent is
777 /// immutable, but not aliasable. This solves the problem. For
778 /// simplicity, we don't give users the way to express this
779 /// borrow, it's just used when translating closures.
782 /// Data is mutable and not aliasable.
786 /// Information describing the capture of an upvar. This is computed
787 /// during `typeck`, specifically by `regionck`.
788 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
789 pub enum UpvarCapture<'tcx> {
790 /// Upvar is captured by value. This is always true when the
791 /// closure is labeled `move`, but can also be true in other cases
792 /// depending on inference.
795 /// Upvar is captured by reference.
796 ByRef(UpvarBorrow<'tcx>),
799 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
800 pub struct UpvarBorrow<'tcx> {
801 /// The kind of borrow: by-ref upvars have access to shared
802 /// immutable borrows, which are not part of the normal language
804 pub kind: BorrowKind,
806 /// Region of the resulting reference.
807 pub region: ty::Region<'tcx>,
810 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
811 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
813 #[derive(Copy, Clone)]
814 pub struct ClosureUpvar<'tcx> {
820 #[derive(Clone, Copy, PartialEq, Eq)]
821 pub enum IntVarValue {
823 UintType(ast::UintTy),
826 #[derive(Clone, Copy, PartialEq, Eq)]
827 pub struct FloatVarValue(pub ast::FloatTy);
829 impl ty::EarlyBoundRegion {
830 pub fn to_bound_region(&self) -> ty::BoundRegion {
831 ty::BoundRegion::BrNamed(self.def_id, self.name)
834 /// Does this early bound region have a name? Early bound regions normally
835 /// always have names except when using anonymous lifetimes (`'_`).
836 pub fn has_name(&self) -> bool {
837 self.name != kw::UnderscoreLifetime.as_interned_str()
841 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
842 pub enum GenericParamDefKind {
846 object_lifetime_default: ObjectLifetimeDefault,
847 synthetic: Option<hir::SyntheticTyParamKind>,
852 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
853 pub struct GenericParamDef {
854 pub name: InternedString,
858 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
859 /// on generic parameter `'a`/`T`, asserts data behind the parameter
860 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
861 pub pure_wrt_drop: bool,
863 pub kind: GenericParamDefKind,
866 impl GenericParamDef {
867 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
868 if let GenericParamDefKind::Lifetime = self.kind {
869 ty::EarlyBoundRegion {
875 bug!("cannot convert a non-lifetime parameter def to an early bound region")
879 pub fn to_bound_region(&self) -> ty::BoundRegion {
880 if let GenericParamDefKind::Lifetime = self.kind {
881 self.to_early_bound_region_data().to_bound_region()
883 bug!("cannot convert a non-lifetime parameter def to an early bound region")
889 pub struct GenericParamCount {
890 pub lifetimes: usize,
895 /// Information about the formal type/lifetime parameters associated
896 /// with an item or method. Analogous to `hir::Generics`.
898 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
899 /// `Self` (optionally), `Lifetime` params..., `Type` params...
900 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
901 pub struct Generics {
902 pub parent: Option<DefId>,
903 pub parent_count: usize,
904 pub params: Vec<GenericParamDef>,
906 /// Reverse map to the `index` field of each `GenericParamDef`
907 #[stable_hasher(ignore)]
908 pub param_def_id_to_index: FxHashMap<DefId, u32>,
911 pub has_late_bound_regions: Option<Span>,
914 impl<'tcx> Generics {
915 pub fn count(&self) -> usize {
916 self.parent_count + self.params.len()
919 pub fn own_counts(&self) -> GenericParamCount {
920 // We could cache this as a property of `GenericParamCount`, but
921 // the aim is to refactor this away entirely eventually and the
922 // presence of this method will be a constant reminder.
923 let mut own_counts: GenericParamCount = Default::default();
925 for param in &self.params {
927 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
928 GenericParamDefKind::Type { .. } => own_counts.types += 1,
929 GenericParamDefKind::Const => own_counts.consts += 1,
936 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
937 if self.own_requires_monomorphization() {
941 if let Some(parent_def_id) = self.parent {
942 let parent = tcx.generics_of(parent_def_id);
943 parent.requires_monomorphization(tcx)
949 pub fn own_requires_monomorphization(&self) -> bool {
950 for param in &self.params {
952 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
953 GenericParamDefKind::Lifetime => {}
961 param: &EarlyBoundRegion,
963 ) -> &'tcx GenericParamDef {
964 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
965 let param = &self.params[index as usize];
967 GenericParamDefKind::Lifetime => param,
968 _ => bug!("expected lifetime parameter, but found another generic parameter")
971 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
972 .region_param(param, tcx)
976 /// Returns the `GenericParamDef` associated with this `ParamTy`.
977 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
978 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
979 let param = &self.params[index as usize];
981 GenericParamDefKind::Type { .. } => param,
982 _ => bug!("expected type parameter, but found another generic parameter")
985 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
986 .type_param(param, tcx)
990 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
991 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
992 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
993 let param = &self.params[index as usize];
995 GenericParamDefKind::Const => param,
996 _ => bug!("expected const parameter, but found another generic parameter")
999 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
1000 .const_param(param, tcx)
1005 /// Bounds on generics.
1006 #[derive(Clone, Default, Debug, HashStable)]
1007 pub struct GenericPredicates<'tcx> {
1008 pub parent: Option<DefId>,
1009 pub predicates: Vec<(Predicate<'tcx>, Span)>,
1012 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
1013 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
1015 impl<'tcx> GenericPredicates<'tcx> {
1019 substs: SubstsRef<'tcx>,
1020 ) -> InstantiatedPredicates<'tcx> {
1021 let mut instantiated = InstantiatedPredicates::empty();
1022 self.instantiate_into(tcx, &mut instantiated, substs);
1026 pub fn instantiate_own(
1029 substs: SubstsRef<'tcx>,
1030 ) -> InstantiatedPredicates<'tcx> {
1031 InstantiatedPredicates {
1032 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1036 fn instantiate_into(
1039 instantiated: &mut InstantiatedPredicates<'tcx>,
1040 substs: SubstsRef<'tcx>,
1042 if let Some(def_id) = self.parent {
1043 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1045 instantiated.predicates.extend(
1046 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1050 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
1051 let mut instantiated = InstantiatedPredicates::empty();
1052 self.instantiate_identity_into(tcx, &mut instantiated);
1056 fn instantiate_identity_into(
1059 instantiated: &mut InstantiatedPredicates<'tcx>,
1061 if let Some(def_id) = self.parent {
1062 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1064 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1067 pub fn instantiate_supertrait(
1070 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1071 ) -> InstantiatedPredicates<'tcx> {
1072 assert_eq!(self.parent, None);
1073 InstantiatedPredicates {
1074 predicates: self.predicates.iter().map(|(pred, _)| {
1075 pred.subst_supertrait(tcx, poly_trait_ref)
1081 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1082 pub enum Predicate<'tcx> {
1083 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1084 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1085 /// would be the type parameters.
1086 Trait(PolyTraitPredicate<'tcx>),
1089 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1092 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1094 /// `where <T as TraitRef>::Name == X`, approximately.
1095 /// See the `ProjectionPredicate` struct for details.
1096 Projection(PolyProjectionPredicate<'tcx>),
1098 /// No syntax: `T` well-formed.
1099 WellFormed(Ty<'tcx>),
1101 /// Trait must be object-safe.
1104 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1105 /// for some substitutions `...` and `T` being a closure type.
1106 /// Satisfied (or refuted) once we know the closure's kind.
1107 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1110 Subtype(PolySubtypePredicate<'tcx>),
1112 /// Constant initializer must evaluate successfully.
1113 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1116 /// The crate outlives map is computed during typeck and contains the
1117 /// outlives of every item in the local crate. You should not use it
1118 /// directly, because to do so will make your pass dependent on the
1119 /// HIR of every item in the local crate. Instead, use
1120 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1122 #[derive(HashStable)]
1123 pub struct CratePredicatesMap<'tcx> {
1124 /// For each struct with outlive bounds, maps to a vector of the
1125 /// predicate of its outlive bounds. If an item has no outlives
1126 /// bounds, it will have no entry.
1127 pub predicates: FxHashMap<DefId, &'tcx [ty::Predicate<'tcx>]>,
1130 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1131 fn as_ref(&self) -> &Predicate<'tcx> {
1136 impl<'tcx> Predicate<'tcx> {
1137 /// Performs a substitution suitable for going from a
1138 /// poly-trait-ref to supertraits that must hold if that
1139 /// poly-trait-ref holds. This is slightly different from a normal
1140 /// substitution in terms of what happens with bound regions. See
1141 /// lengthy comment below for details.
1142 pub fn subst_supertrait(
1145 trait_ref: &ty::PolyTraitRef<'tcx>,
1146 ) -> ty::Predicate<'tcx> {
1147 // The interaction between HRTB and supertraits is not entirely
1148 // obvious. Let me walk you (and myself) through an example.
1150 // Let's start with an easy case. Consider two traits:
1152 // trait Foo<'a>: Bar<'a,'a> { }
1153 // trait Bar<'b,'c> { }
1155 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1156 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1157 // knew that `Foo<'x>` (for any 'x) then we also know that
1158 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1159 // normal substitution.
1161 // In terms of why this is sound, the idea is that whenever there
1162 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1163 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1164 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1167 // Another example to be careful of is this:
1169 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1170 // trait Bar1<'b,'c> { }
1172 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1173 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1174 // reason is similar to the previous example: any impl of
1175 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1176 // basically we would want to collapse the bound lifetimes from
1177 // the input (`trait_ref`) and the supertraits.
1179 // To achieve this in practice is fairly straightforward. Let's
1180 // consider the more complicated scenario:
1182 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1183 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1184 // where both `'x` and `'b` would have a DB index of 1.
1185 // The substitution from the input trait-ref is therefore going to be
1186 // `'a => 'x` (where `'x` has a DB index of 1).
1187 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1188 // early-bound parameter and `'b' is a late-bound parameter with a
1190 // - If we replace `'a` with `'x` from the input, it too will have
1191 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1192 // just as we wanted.
1194 // There is only one catch. If we just apply the substitution `'a
1195 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1196 // adjust the DB index because we substituting into a binder (it
1197 // tries to be so smart...) resulting in `for<'x> for<'b>
1198 // Bar1<'x,'b>` (we have no syntax for this, so use your
1199 // imagination). Basically the 'x will have DB index of 2 and 'b
1200 // will have DB index of 1. Not quite what we want. So we apply
1201 // the substitution to the *contents* of the trait reference,
1202 // rather than the trait reference itself (put another way, the
1203 // substitution code expects equal binding levels in the values
1204 // from the substitution and the value being substituted into, and
1205 // this trick achieves that).
1207 let substs = &trait_ref.skip_binder().substs;
1209 Predicate::Trait(ref binder) =>
1210 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1211 Predicate::Subtype(ref binder) =>
1212 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1213 Predicate::RegionOutlives(ref binder) =>
1214 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1215 Predicate::TypeOutlives(ref binder) =>
1216 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1217 Predicate::Projection(ref binder) =>
1218 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1219 Predicate::WellFormed(data) =>
1220 Predicate::WellFormed(data.subst(tcx, substs)),
1221 Predicate::ObjectSafe(trait_def_id) =>
1222 Predicate::ObjectSafe(trait_def_id),
1223 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1224 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1225 Predicate::ConstEvaluatable(def_id, const_substs) =>
1226 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1231 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1232 pub struct TraitPredicate<'tcx> {
1233 pub trait_ref: TraitRef<'tcx>
1236 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1238 impl<'tcx> TraitPredicate<'tcx> {
1239 pub fn def_id(&self) -> DefId {
1240 self.trait_ref.def_id
1243 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
1244 self.trait_ref.input_types()
1247 pub fn self_ty(&self) -> Ty<'tcx> {
1248 self.trait_ref.self_ty()
1252 impl<'tcx> PolyTraitPredicate<'tcx> {
1253 pub fn def_id(&self) -> DefId {
1254 // Ok to skip binder since trait def-ID does not care about regions.
1255 self.skip_binder().def_id()
1259 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord,
1260 Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1261 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1262 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1263 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1264 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1265 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1266 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1268 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, HashStable)]
1269 pub struct SubtypePredicate<'tcx> {
1270 pub a_is_expected: bool,
1274 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1276 /// This kind of predicate has no *direct* correspondent in the
1277 /// syntax, but it roughly corresponds to the syntactic forms:
1279 /// 1. `T: TraitRef<..., Item = Type>`
1280 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1282 /// In particular, form #1 is "desugared" to the combination of a
1283 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1284 /// predicates. Form #2 is a broader form in that it also permits
1285 /// equality between arbitrary types. Processing an instance of
1286 /// Form #2 eventually yields one of these `ProjectionPredicate`
1287 /// instances to normalize the LHS.
1288 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
1289 pub struct ProjectionPredicate<'tcx> {
1290 pub projection_ty: ProjectionTy<'tcx>,
1294 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1296 impl<'tcx> PolyProjectionPredicate<'tcx> {
1297 /// Returns the `DefId` of the associated item being projected.
1298 pub fn item_def_id(&self) -> DefId {
1299 self.skip_binder().projection_ty.item_def_id
1303 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_>) -> PolyTraitRef<'tcx> {
1304 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1305 // `self.0.trait_ref` is permitted to have escaping regions.
1306 // This is because here `self` has a `Binder` and so does our
1307 // return value, so we are preserving the number of binding
1309 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1312 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1313 self.map_bound(|predicate| predicate.ty)
1316 /// The `DefId` of the `TraitItem` for the associated type.
1318 /// Note that this is not the `DefId` of the `TraitRef` containing this
1319 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1320 pub fn projection_def_id(&self) -> DefId {
1321 // Ok to skip binder since trait def-ID does not care about regions.
1322 self.skip_binder().projection_ty.item_def_id
1326 pub trait ToPolyTraitRef<'tcx> {
1327 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1330 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1331 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1332 ty::Binder::dummy(self.clone())
1336 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1337 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1338 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1342 pub trait ToPredicate<'tcx> {
1343 fn to_predicate(&self) -> Predicate<'tcx>;
1346 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1347 fn to_predicate(&self) -> Predicate<'tcx> {
1348 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1349 trait_ref: self.clone()
1354 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1355 fn to_predicate(&self) -> Predicate<'tcx> {
1356 ty::Predicate::Trait(self.to_poly_trait_predicate())
1360 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1361 fn to_predicate(&self) -> Predicate<'tcx> {
1362 Predicate::RegionOutlives(self.clone())
1366 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1367 fn to_predicate(&self) -> Predicate<'tcx> {
1368 Predicate::TypeOutlives(self.clone())
1372 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1373 fn to_predicate(&self) -> Predicate<'tcx> {
1374 Predicate::Projection(self.clone())
1378 // A custom iterator used by `Predicate::walk_tys`.
1379 enum WalkTysIter<'tcx, I, J, K>
1380 where I: Iterator<Item = Ty<'tcx>>,
1381 J: Iterator<Item = Ty<'tcx>>,
1382 K: Iterator<Item = Ty<'tcx>>
1386 Two(Ty<'tcx>, Ty<'tcx>),
1392 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1393 where I: Iterator<Item = Ty<'tcx>>,
1394 J: Iterator<Item = Ty<'tcx>>,
1395 K: Iterator<Item = Ty<'tcx>>
1397 type Item = Ty<'tcx>;
1399 fn next(&mut self) -> Option<Ty<'tcx>> {
1401 WalkTysIter::None => None,
1402 WalkTysIter::One(item) => {
1403 *self = WalkTysIter::None;
1406 WalkTysIter::Two(item1, item2) => {
1407 *self = WalkTysIter::One(item2);
1410 WalkTysIter::Types(ref mut iter) => {
1413 WalkTysIter::InputTypes(ref mut iter) => {
1416 WalkTysIter::ProjectionTypes(ref mut iter) => {
1423 impl<'tcx> Predicate<'tcx> {
1424 /// Iterates over the types in this predicate. Note that in all
1425 /// cases this is skipping over a binder, so late-bound regions
1426 /// with depth 0 are bound by the predicate.
1427 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1429 ty::Predicate::Trait(ref data) => {
1430 WalkTysIter::InputTypes(data.skip_binder().input_types())
1432 ty::Predicate::Subtype(binder) => {
1433 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1434 WalkTysIter::Two(a, b)
1436 ty::Predicate::TypeOutlives(binder) => {
1437 WalkTysIter::One(binder.skip_binder().0)
1439 ty::Predicate::RegionOutlives(..) => {
1442 ty::Predicate::Projection(ref data) => {
1443 let inner = data.skip_binder();
1444 WalkTysIter::ProjectionTypes(
1445 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1447 ty::Predicate::WellFormed(data) => {
1448 WalkTysIter::One(data)
1450 ty::Predicate::ObjectSafe(_trait_def_id) => {
1453 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1454 WalkTysIter::Types(closure_substs.substs.types())
1456 ty::Predicate::ConstEvaluatable(_, substs) => {
1457 WalkTysIter::Types(substs.types())
1462 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1464 Predicate::Trait(ref t) => {
1465 Some(t.to_poly_trait_ref())
1467 Predicate::Projection(..) |
1468 Predicate::Subtype(..) |
1469 Predicate::RegionOutlives(..) |
1470 Predicate::WellFormed(..) |
1471 Predicate::ObjectSafe(..) |
1472 Predicate::ClosureKind(..) |
1473 Predicate::TypeOutlives(..) |
1474 Predicate::ConstEvaluatable(..) => {
1480 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1482 Predicate::TypeOutlives(data) => {
1485 Predicate::Trait(..) |
1486 Predicate::Projection(..) |
1487 Predicate::Subtype(..) |
1488 Predicate::RegionOutlives(..) |
1489 Predicate::WellFormed(..) |
1490 Predicate::ObjectSafe(..) |
1491 Predicate::ClosureKind(..) |
1492 Predicate::ConstEvaluatable(..) => {
1499 /// Represents the bounds declared on a particular set of type
1500 /// parameters. Should eventually be generalized into a flag list of
1501 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1502 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1503 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1504 /// the `GenericPredicates` are expressed in terms of the bound type
1505 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1506 /// represented a set of bounds for some particular instantiation,
1507 /// meaning that the generic parameters have been substituted with
1512 /// struct Foo<T, U: Bar<T>> { ... }
1514 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1515 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1516 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1517 /// [usize:Bar<isize>]]`.
1518 #[derive(Clone, Debug)]
1519 pub struct InstantiatedPredicates<'tcx> {
1520 pub predicates: Vec<Predicate<'tcx>>,
1523 impl<'tcx> InstantiatedPredicates<'tcx> {
1524 pub fn empty() -> InstantiatedPredicates<'tcx> {
1525 InstantiatedPredicates { predicates: vec![] }
1528 pub fn is_empty(&self) -> bool {
1529 self.predicates.is_empty()
1534 /// "Universes" are used during type- and trait-checking in the
1535 /// presence of `for<..>` binders to control what sets of names are
1536 /// visible. Universes are arranged into a tree: the root universe
1537 /// contains names that are always visible. Each child then adds a new
1538 /// set of names that are visible, in addition to those of its parent.
1539 /// We say that the child universe "extends" the parent universe with
1542 /// To make this more concrete, consider this program:
1546 /// fn bar<T>(x: T) {
1547 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1551 /// The struct name `Foo` is in the root universe U0. But the type
1552 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1553 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1554 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1555 /// region `'a` is in a universe U2 that extends U1, because we can
1556 /// name it inside the fn type but not outside.
1558 /// Universes are used to do type- and trait-checking around these
1559 /// "forall" binders (also called **universal quantification**). The
1560 /// idea is that when, in the body of `bar`, we refer to `T` as a
1561 /// type, we aren't referring to any type in particular, but rather a
1562 /// kind of "fresh" type that is distinct from all other types we have
1563 /// actually declared. This is called a **placeholder** type, and we
1564 /// use universes to talk about this. In other words, a type name in
1565 /// universe 0 always corresponds to some "ground" type that the user
1566 /// declared, but a type name in a non-zero universe is a placeholder
1567 /// type -- an idealized representative of "types in general" that we
1568 /// use for checking generic functions.
1569 pub struct UniverseIndex {
1570 DEBUG_FORMAT = "U{}",
1574 impl_stable_hash_for!(struct UniverseIndex { private });
1576 impl UniverseIndex {
1577 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1579 /// Returns the "next" universe index in order -- this new index
1580 /// is considered to extend all previous universes. This
1581 /// corresponds to entering a `forall` quantifier. So, for
1582 /// example, suppose we have this type in universe `U`:
1585 /// for<'a> fn(&'a u32)
1588 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1589 /// new universe that extends `U` -- in this new universe, we can
1590 /// name the region `'a`, but that region was not nameable from
1591 /// `U` because it was not in scope there.
1592 pub fn next_universe(self) -> UniverseIndex {
1593 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1596 /// Returns `true` if `self` can name a name from `other` -- in other words,
1597 /// if the set of names in `self` is a superset of those in
1598 /// `other` (`self >= other`).
1599 pub fn can_name(self, other: UniverseIndex) -> bool {
1600 self.private >= other.private
1603 /// Returns `true` if `self` cannot name some names from `other` -- in other
1604 /// words, if the set of names in `self` is a strict subset of
1605 /// those in `other` (`self < other`).
1606 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1607 self.private < other.private
1611 /// The "placeholder index" fully defines a placeholder region.
1612 /// Placeholder regions are identified by both a **universe** as well
1613 /// as a "bound-region" within that universe. The `bound_region` is
1614 /// basically a name -- distinct bound regions within the same
1615 /// universe are just two regions with an unknown relationship to one
1617 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1618 pub struct Placeholder<T> {
1619 pub universe: UniverseIndex,
1623 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1625 T: HashStable<StableHashingContext<'a>>,
1627 fn hash_stable<W: StableHasherResult>(
1629 hcx: &mut StableHashingContext<'a>,
1630 hasher: &mut StableHasher<W>
1632 self.universe.hash_stable(hcx, hasher);
1633 self.name.hash_stable(hcx, hasher);
1637 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1639 pub type PlaceholderType = Placeholder<BoundVar>;
1641 pub type PlaceholderConst = Placeholder<BoundVar>;
1643 /// When type checking, we use the `ParamEnv` to track
1644 /// details about the set of where-clauses that are in scope at this
1645 /// particular point.
1646 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
1647 pub struct ParamEnv<'tcx> {
1648 /// Obligations that the caller must satisfy. This is basically
1649 /// the set of bounds on the in-scope type parameters, translated
1650 /// into Obligations, and elaborated and normalized.
1651 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1653 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1654 /// want `Reveal::All` -- note that this is always paired with an
1655 /// empty environment. To get that, use `ParamEnv::reveal()`.
1656 pub reveal: traits::Reveal,
1658 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1659 /// register that `def_id` (useful for transitioning to the chalk trait
1661 pub def_id: Option<DefId>,
1664 impl<'tcx> ParamEnv<'tcx> {
1665 /// Construct a trait environment suitable for contexts where
1666 /// there are no where-clauses in scope. Hidden types (like `impl
1667 /// Trait`) are left hidden, so this is suitable for ordinary
1670 pub fn empty() -> Self {
1671 Self::new(List::empty(), Reveal::UserFacing, None)
1674 /// Construct a trait environment with no where-clauses in scope
1675 /// where the values of all `impl Trait` and other hidden types
1676 /// are revealed. This is suitable for monomorphized, post-typeck
1677 /// environments like codegen or doing optimizations.
1679 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1680 /// or invoke `param_env.with_reveal_all()`.
1682 pub fn reveal_all() -> Self {
1683 Self::new(List::empty(), Reveal::All, None)
1686 /// Construct a trait environment with the given set of predicates.
1689 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1691 def_id: Option<DefId>
1693 ty::ParamEnv { caller_bounds, reveal, def_id }
1696 /// Returns a new parameter environment with the same clauses, but
1697 /// which "reveals" the true results of projections in all cases
1698 /// (even for associated types that are specializable). This is
1699 /// the desired behavior during codegen and certain other special
1700 /// contexts; normally though we want to use `Reveal::UserFacing`,
1701 /// which is the default.
1702 pub fn with_reveal_all(self) -> Self {
1703 ty::ParamEnv { reveal: Reveal::All, ..self }
1706 /// Returns this same environment but with no caller bounds.
1707 pub fn without_caller_bounds(self) -> Self {
1708 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1711 /// Creates a suitable environment in which to perform trait
1712 /// queries on the given value. When type-checking, this is simply
1713 /// the pair of the environment plus value. But when reveal is set to
1714 /// All, then if `value` does not reference any type parameters, we will
1715 /// pair it with the empty environment. This improves caching and is generally
1718 /// N.B., we preserve the environment when type-checking because it
1719 /// is possible for the user to have wacky where-clauses like
1720 /// `where Box<u32>: Copy`, which are clearly never
1721 /// satisfiable. We generally want to behave as if they were true,
1722 /// although the surrounding function is never reachable.
1723 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1725 Reveal::UserFacing => {
1733 if value.has_placeholders()
1734 || value.needs_infer()
1735 || value.has_param_types()
1736 || value.has_self_ty()
1744 param_env: self.without_caller_bounds(),
1753 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1754 pub struct ParamEnvAnd<'tcx, T> {
1755 pub param_env: ParamEnv<'tcx>,
1759 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1760 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1761 (self.param_env, self.value)
1765 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1767 T: HashStable<StableHashingContext<'a>>,
1769 fn hash_stable<W: StableHasherResult>(&self,
1770 hcx: &mut StableHashingContext<'a>,
1771 hasher: &mut StableHasher<W>) {
1777 param_env.hash_stable(hcx, hasher);
1778 value.hash_stable(hcx, hasher);
1782 #[derive(Copy, Clone, Debug, HashStable)]
1783 pub struct Destructor {
1784 /// The `DefId` of the destructor method
1789 #[derive(HashStable)]
1790 pub struct AdtFlags: u32 {
1791 const NO_ADT_FLAGS = 0;
1792 /// Indicates whether the ADT is an enum.
1793 const IS_ENUM = 1 << 0;
1794 /// Indicates whether the ADT is a union.
1795 const IS_UNION = 1 << 1;
1796 /// Indicates whether the ADT is a struct.
1797 const IS_STRUCT = 1 << 2;
1798 /// Indicates whether the ADT is a struct and has a constructor.
1799 const HAS_CTOR = 1 << 3;
1800 /// Indicates whether the type is a `PhantomData`.
1801 const IS_PHANTOM_DATA = 1 << 4;
1802 /// Indicates whether the type has a `#[fundamental]` attribute.
1803 const IS_FUNDAMENTAL = 1 << 5;
1804 /// Indicates whether the type is a `Box`.
1805 const IS_BOX = 1 << 6;
1806 /// Indicates whether the type is an `Arc`.
1807 const IS_ARC = 1 << 7;
1808 /// Indicates whether the type is an `Rc`.
1809 const IS_RC = 1 << 8;
1810 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1811 /// (i.e., this flag is never set unless this ADT is an enum).
1812 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1817 #[derive(HashStable)]
1818 pub struct VariantFlags: u32 {
1819 const NO_VARIANT_FLAGS = 0;
1820 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1821 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1825 /// Definition of a variant -- a struct's fields or a enum variant.
1827 pub struct VariantDef {
1828 /// `DefId` that identifies the variant itself.
1829 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1831 /// `DefId` that identifies the variant's constructor.
1832 /// If this variant is a struct variant, then this is `None`.
1833 pub ctor_def_id: Option<DefId>,
1834 /// Variant or struct name.
1836 /// Discriminant of this variant.
1837 pub discr: VariantDiscr,
1838 /// Fields of this variant.
1839 pub fields: Vec<FieldDef>,
1840 /// Type of constructor of variant.
1841 pub ctor_kind: CtorKind,
1842 /// Flags of the variant (e.g. is field list non-exhaustive)?
1843 flags: VariantFlags,
1845 pub recovered: bool,
1848 impl<'tcx> VariantDef {
1849 /// Creates a new `VariantDef`.
1851 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1852 /// represents an enum variant).
1854 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1855 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1857 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1858 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1859 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1860 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1861 /// built-in trait), and we do not want to load attributes twice.
1863 /// If someone speeds up attribute loading to not be a performance concern, they can
1864 /// remove this hack and use the constructor `DefId` everywhere.
1868 variant_did: Option<DefId>,
1869 ctor_def_id: Option<DefId>,
1870 discr: VariantDiscr,
1871 fields: Vec<FieldDef>,
1872 ctor_kind: CtorKind,
1878 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1879 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1880 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1883 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1884 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1885 debug!("found non-exhaustive field list for {:?}", parent_did);
1886 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1887 } else if let Some(variant_did) = variant_did {
1888 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1889 debug!("found non-exhaustive field list for {:?}", variant_did);
1890 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1895 def_id: variant_did.unwrap_or(parent_did),
1906 /// Is this field list non-exhaustive?
1908 pub fn is_field_list_non_exhaustive(&self) -> bool {
1909 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1913 impl_stable_hash_for!(struct VariantDef {
1916 ident -> (ident.name),
1924 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1925 pub enum VariantDiscr {
1926 /// Explicit value for this variant, i.e., `X = 123`.
1927 /// The `DefId` corresponds to the embedded constant.
1930 /// The previous variant's discriminant plus one.
1931 /// For efficiency reasons, the distance from the
1932 /// last `Explicit` discriminant is being stored,
1933 /// or `0` for the first variant, if it has none.
1937 #[derive(Debug, HashStable)]
1938 pub struct FieldDef {
1940 #[stable_hasher(project(name))]
1942 pub vis: Visibility,
1945 /// The definition of an abstract data type -- a struct or enum.
1947 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1949 /// `DefId` of the struct, enum or union item.
1951 /// Variants of the ADT. If this is a struct or enum, then there will be a single variant.
1952 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1953 /// Flags of the ADT (e.g. is this a struct? is this non-exhaustive?)
1955 /// Repr options provided by the user.
1956 pub repr: ReprOptions,
1959 impl PartialOrd for AdtDef {
1960 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1961 Some(self.cmp(&other))
1965 /// There should be only one AdtDef for each `did`, therefore
1966 /// it is fine to implement `Ord` only based on `did`.
1967 impl Ord for AdtDef {
1968 fn cmp(&self, other: &AdtDef) -> Ordering {
1969 self.did.cmp(&other.did)
1973 impl PartialEq for AdtDef {
1974 // AdtDef are always interned and this is part of TyS equality
1976 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1979 impl Eq for AdtDef {}
1981 impl Hash for AdtDef {
1983 fn hash<H: Hasher>(&self, s: &mut H) {
1984 (self as *const AdtDef).hash(s)
1988 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1989 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1994 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1997 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1998 fn hash_stable<W: StableHasherResult>(&self,
1999 hcx: &mut StableHashingContext<'a>,
2000 hasher: &mut StableHasher<W>) {
2002 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
2005 let hash: Fingerprint = CACHE.with(|cache| {
2006 let addr = self as *const AdtDef as usize;
2007 *cache.borrow_mut().entry(addr).or_insert_with(|| {
2015 let mut hasher = StableHasher::new();
2016 did.hash_stable(hcx, &mut hasher);
2017 variants.hash_stable(hcx, &mut hasher);
2018 flags.hash_stable(hcx, &mut hasher);
2019 repr.hash_stable(hcx, &mut hasher);
2025 hash.hash_stable(hcx, hasher);
2029 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2030 pub enum AdtKind { Struct, Union, Enum }
2032 impl Into<DataTypeKind> for AdtKind {
2033 fn into(self) -> DataTypeKind {
2035 AdtKind::Struct => DataTypeKind::Struct,
2036 AdtKind::Union => DataTypeKind::Union,
2037 AdtKind::Enum => DataTypeKind::Enum,
2043 #[derive(RustcEncodable, RustcDecodable, Default)]
2044 pub struct ReprFlags: u8 {
2045 const IS_C = 1 << 0;
2046 const IS_SIMD = 1 << 1;
2047 const IS_TRANSPARENT = 1 << 2;
2048 // Internal only for now. If true, don't reorder fields.
2049 const IS_LINEAR = 1 << 3;
2051 // Any of these flags being set prevent field reordering optimisation.
2052 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2053 ReprFlags::IS_SIMD.bits |
2054 ReprFlags::IS_LINEAR.bits;
2058 impl_stable_hash_for!(struct ReprFlags {
2062 /// Represents the repr options provided by the user,
2063 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
2064 pub struct ReprOptions {
2065 pub int: Option<attr::IntType>,
2068 pub flags: ReprFlags,
2071 impl_stable_hash_for!(struct ReprOptions {
2079 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2080 let mut flags = ReprFlags::empty();
2081 let mut size = None;
2082 let mut max_align = 0;
2083 let mut min_pack = 0;
2084 for attr in tcx.get_attrs(did).iter() {
2085 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2086 flags.insert(match r {
2087 attr::ReprC => ReprFlags::IS_C,
2088 attr::ReprPacked(pack) => {
2089 min_pack = if min_pack > 0 {
2090 cmp::min(pack, min_pack)
2096 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2097 attr::ReprSimd => ReprFlags::IS_SIMD,
2098 attr::ReprInt(i) => {
2102 attr::ReprAlign(align) => {
2103 max_align = cmp::max(align, max_align);
2110 // This is here instead of layout because the choice must make it into metadata.
2111 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2112 flags.insert(ReprFlags::IS_LINEAR);
2114 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2118 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2120 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2122 pub fn packed(&self) -> bool { self.pack > 0 }
2124 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2126 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2128 pub fn discr_type(&self) -> attr::IntType {
2129 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2132 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2133 /// layout" optimizations, such as representing `Foo<&T>` as a
2135 pub fn inhibit_enum_layout_opt(&self) -> bool {
2136 self.c() || self.int.is_some()
2139 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2140 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2141 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2142 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
2146 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2147 pub fn inhibit_union_abi_opt(&self) -> bool {
2153 /// Creates a new `AdtDef`.
2158 variants: IndexVec<VariantIdx, VariantDef>,
2161 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2162 let mut flags = AdtFlags::NO_ADT_FLAGS;
2164 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2165 debug!("found non-exhaustive variant list for {:?}", did);
2166 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2169 flags |= match kind {
2170 AdtKind::Enum => AdtFlags::IS_ENUM,
2171 AdtKind::Union => AdtFlags::IS_UNION,
2172 AdtKind::Struct => AdtFlags::IS_STRUCT,
2175 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2176 flags |= AdtFlags::HAS_CTOR;
2179 let attrs = tcx.get_attrs(did);
2180 if attr::contains_name(&attrs, sym::fundamental) {
2181 flags |= AdtFlags::IS_FUNDAMENTAL;
2183 if Some(did) == tcx.lang_items().phantom_data() {
2184 flags |= AdtFlags::IS_PHANTOM_DATA;
2186 if Some(did) == tcx.lang_items().owned_box() {
2187 flags |= AdtFlags::IS_BOX;
2189 if Some(did) == tcx.lang_items().arc() {
2190 flags |= AdtFlags::IS_ARC;
2192 if Some(did) == tcx.lang_items().rc() {
2193 flags |= AdtFlags::IS_RC;
2204 /// Returns `true` if this is a struct.
2206 pub fn is_struct(&self) -> bool {
2207 self.flags.contains(AdtFlags::IS_STRUCT)
2210 /// Returns `true` if this is a union.
2212 pub fn is_union(&self) -> bool {
2213 self.flags.contains(AdtFlags::IS_UNION)
2216 /// Returns `true` if this is a enum.
2218 pub fn is_enum(&self) -> bool {
2219 self.flags.contains(AdtFlags::IS_ENUM)
2222 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2224 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2225 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2228 /// Returns the kind of the ADT.
2230 pub fn adt_kind(&self) -> AdtKind {
2233 } else if self.is_union() {
2240 /// Returns a description of this abstract data type.
2241 pub fn descr(&self) -> &'static str {
2242 match self.adt_kind() {
2243 AdtKind::Struct => "struct",
2244 AdtKind::Union => "union",
2245 AdtKind::Enum => "enum",
2249 /// Returns a description of a variant of this abstract data type.
2251 pub fn variant_descr(&self) -> &'static str {
2252 match self.adt_kind() {
2253 AdtKind::Struct => "struct",
2254 AdtKind::Union => "union",
2255 AdtKind::Enum => "variant",
2259 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2261 pub fn has_ctor(&self) -> bool {
2262 self.flags.contains(AdtFlags::HAS_CTOR)
2265 /// Returns `true` if this type is `#[fundamental]` for the purposes
2266 /// of coherence checking.
2268 pub fn is_fundamental(&self) -> bool {
2269 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2272 /// Returns `true` if this is `PhantomData<T>`.
2274 pub fn is_phantom_data(&self) -> bool {
2275 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2278 /// Returns `true` if this is `Arc<T>`.
2279 pub fn is_arc(&self) -> bool {
2280 self.flags.contains(AdtFlags::IS_ARC)
2283 /// Returns `true` if this is `Rc<T>`.
2284 pub fn is_rc(&self) -> bool {
2285 self.flags.contains(AdtFlags::IS_RC)
2288 /// Returns `true` if this is Box<T>.
2290 pub fn is_box(&self) -> bool {
2291 self.flags.contains(AdtFlags::IS_BOX)
2294 /// Returns `true` if this type has a destructor.
2295 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2296 self.destructor(tcx).is_some()
2299 /// Asserts this is a struct or union and returns its unique variant.
2300 pub fn non_enum_variant(&self) -> &VariantDef {
2301 assert!(self.is_struct() || self.is_union());
2302 &self.variants[VariantIdx::new(0)]
2306 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> &'tcx GenericPredicates<'tcx> {
2307 tcx.predicates_of(self.did)
2310 /// Returns an iterator over all fields contained
2313 pub fn all_fields(&self) -> impl Iterator<Item=&FieldDef> + Clone {
2314 self.variants.iter().flat_map(|v| v.fields.iter())
2317 pub fn is_payloadfree(&self) -> bool {
2318 !self.variants.is_empty() &&
2319 self.variants.iter().all(|v| v.fields.is_empty())
2322 /// Return a `VariantDef` given a variant id.
2323 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2324 self.variants.iter().find(|v| v.def_id == vid)
2325 .expect("variant_with_id: unknown variant")
2328 /// Return a `VariantDef` given a constructor id.
2329 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2330 self.variants.iter().find(|v| v.ctor_def_id == Some(cid))
2331 .expect("variant_with_ctor_id: unknown variant")
2334 /// Return the index of `VariantDef` given a variant id.
2335 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2336 self.variants.iter_enumerated().find(|(_, v)| v.def_id == vid)
2337 .expect("variant_index_with_id: unknown variant").0
2340 /// Return the index of `VariantDef` given a constructor id.
2341 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2342 self.variants.iter_enumerated().find(|(_, v)| v.ctor_def_id == Some(cid))
2343 .expect("variant_index_with_ctor_id: unknown variant").0
2346 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2348 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2349 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2350 Res::Def(DefKind::Struct, _) | Res::Def(DefKind::Union, _) |
2351 Res::Def(DefKind::TyAlias, _) | Res::Def(DefKind::AssocTy, _) | Res::SelfTy(..) |
2352 Res::SelfCtor(..) => self.non_enum_variant(),
2353 _ => bug!("unexpected res {:?} in variant_of_res", res)
2358 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2359 let param_env = ParamEnv::empty();
2360 let repr_type = self.repr.discr_type();
2361 let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), expr_did);
2362 let instance = ty::Instance::new(expr_did, substs);
2363 let cid = GlobalId {
2367 match tcx.const_eval(param_env.and(cid)) {
2369 // FIXME: Find the right type and use it instead of `val.ty` here
2370 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2371 trace!("discriminants: {} ({:?})", b, repr_type);
2377 info!("invalid enum discriminant: {:#?}", val);
2378 crate::mir::interpret::struct_error(
2379 tcx.at(tcx.def_span(expr_did)),
2380 "constant evaluation of enum discriminant resulted in non-integer",
2385 Err(ErrorHandled::Reported) => {
2386 if !expr_did.is_local() {
2387 span_bug!(tcx.def_span(expr_did),
2388 "variant discriminant evaluation succeeded \
2389 in its crate but failed locally");
2393 Err(ErrorHandled::TooGeneric) => span_bug!(
2394 tcx.def_span(expr_did),
2395 "enum discriminant depends on generic arguments",
2401 pub fn discriminants(
2404 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2405 let repr_type = self.repr.discr_type();
2406 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2407 let mut prev_discr = None::<Discr<'tcx>>;
2408 self.variants.iter_enumerated().map(move |(i, v)| {
2409 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2410 if let VariantDiscr::Explicit(expr_did) = v.discr {
2411 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2415 prev_discr = Some(discr);
2422 pub fn variant_range(&self) -> Range<VariantIdx> {
2423 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2426 /// Computes the discriminant value used by a specific variant.
2427 /// Unlike `discriminants`, this is (amortized) constant-time,
2428 /// only doing at most one query for evaluating an explicit
2429 /// discriminant (the last one before the requested variant),
2430 /// assuming there are no constant-evaluation errors there.
2432 pub fn discriminant_for_variant(
2435 variant_index: VariantIdx,
2437 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2438 let explicit_value = val
2439 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2440 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2441 explicit_value.checked_add(tcx, offset as u128).0
2444 /// Yields a `DefId` for the discriminant and an offset to add to it
2445 /// Alternatively, if there is no explicit discriminant, returns the
2446 /// inferred discriminant directly.
2447 pub fn discriminant_def_for_variant(
2449 variant_index: VariantIdx,
2450 ) -> (Option<DefId>, u32) {
2451 let mut explicit_index = variant_index.as_u32();
2454 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2455 ty::VariantDiscr::Relative(0) => {
2459 ty::VariantDiscr::Relative(distance) => {
2460 explicit_index -= distance;
2462 ty::VariantDiscr::Explicit(did) => {
2463 expr_did = Some(did);
2468 (expr_did, variant_index.as_u32() - explicit_index)
2471 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2472 tcx.adt_destructor(self.did)
2475 /// Returns a list of types such that `Self: Sized` if and only
2476 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2478 /// Oddly enough, checking that the sized-constraint is `Sized` is
2479 /// actually more expressive than checking all members:
2480 /// the `Sized` trait is inductive, so an associated type that references
2481 /// `Self` would prevent its containing ADT from being `Sized`.
2483 /// Due to normalization being eager, this applies even if
2484 /// the associated type is behind a pointer (e.g., issue #31299).
2485 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2486 tcx.adt_sized_constraint(self.did).0
2489 fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> {
2490 let result = match ty.sty {
2491 Bool | Char | Int(..) | Uint(..) | Float(..) |
2492 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2493 Array(..) | Closure(..) | Generator(..) | Never => {
2502 GeneratorWitness(..) => {
2503 // these are never sized - return the target type
2510 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2514 Adt(adt, substs) => {
2516 let adt_tys = adt.sized_constraint(tcx);
2517 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2520 .map(|ty| ty.subst(tcx, substs))
2521 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2525 Projection(..) | Opaque(..) => {
2526 // must calculate explicitly.
2527 // FIXME: consider special-casing always-Sized projections
2531 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2534 // perf hack: if there is a `T: Sized` bound, then
2535 // we know that `T` is Sized and do not need to check
2538 let sized_trait = match tcx.lang_items().sized_trait() {
2540 _ => return vec![ty]
2542 let sized_predicate = Binder::dummy(TraitRef {
2543 def_id: sized_trait,
2544 substs: tcx.mk_substs_trait(ty, &[])
2546 let predicates = &tcx.predicates_of(self.did).predicates;
2547 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2557 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2561 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2566 impl<'tcx> FieldDef {
2567 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2568 tcx.type_of(self.did).subst(tcx, subst)
2572 /// Represents the various closure traits in the language. This
2573 /// will determine the type of the environment (`self`, in the
2574 /// desugaring) argument that the closure expects.
2576 /// You can get the environment type of a closure using
2577 /// `tcx.closure_env_ty()`.
2578 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug,
2579 RustcEncodable, RustcDecodable, HashStable)]
2580 pub enum ClosureKind {
2581 // Warning: Ordering is significant here! The ordering is chosen
2582 // because the trait Fn is a subtrait of FnMut and so in turn, and
2583 // hence we order it so that Fn < FnMut < FnOnce.
2589 impl<'tcx> ClosureKind {
2590 // This is the initial value used when doing upvar inference.
2591 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2593 pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
2595 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2596 ClosureKind::FnMut => {
2597 tcx.require_lang_item(FnMutTraitLangItem)
2599 ClosureKind::FnOnce => {
2600 tcx.require_lang_item(FnOnceTraitLangItem)
2605 /// Returns `true` if this a type that impls this closure kind
2606 /// must also implement `other`.
2607 pub fn extends(self, other: ty::ClosureKind) -> bool {
2608 match (self, other) {
2609 (ClosureKind::Fn, ClosureKind::Fn) => true,
2610 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2611 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2612 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2613 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2614 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2619 /// Returns the representative scalar type for this closure kind.
2620 /// See `TyS::to_opt_closure_kind` for more details.
2621 pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
2623 ty::ClosureKind::Fn => tcx.types.i8,
2624 ty::ClosureKind::FnMut => tcx.types.i16,
2625 ty::ClosureKind::FnOnce => tcx.types.i32,
2630 impl<'tcx> TyS<'tcx> {
2631 /// Iterator that walks `self` and any types reachable from
2632 /// `self`, in depth-first order. Note that just walks the types
2633 /// that appear in `self`, it does not descend into the fields of
2634 /// structs or variants. For example:
2637 /// isize => { isize }
2638 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2639 /// [isize] => { [isize], isize }
2641 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2642 TypeWalker::new(self)
2645 /// Iterator that walks the immediate children of `self`. Hence
2646 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2647 /// (but not `i32`, like `walk`).
2648 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2649 walk::walk_shallow(self)
2652 /// Walks `ty` and any types appearing within `ty`, invoking the
2653 /// callback `f` on each type. If the callback returns `false`, then the
2654 /// children of the current type are ignored.
2656 /// Note: prefer `ty.walk()` where possible.
2657 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2658 where F: FnMut(Ty<'tcx>) -> bool
2660 let mut walker = self.walk();
2661 while let Some(ty) = walker.next() {
2663 walker.skip_current_subtree();
2670 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2672 hir::MutMutable => MutBorrow,
2673 hir::MutImmutable => ImmBorrow,
2677 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2678 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2679 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2681 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2683 MutBorrow => hir::MutMutable,
2684 ImmBorrow => hir::MutImmutable,
2686 // We have no type corresponding to a unique imm borrow, so
2687 // use `&mut`. It gives all the capabilities of an `&uniq`
2688 // and hence is a safe "over approximation".
2689 UniqueImmBorrow => hir::MutMutable,
2693 pub fn to_user_str(&self) -> &'static str {
2695 MutBorrow => "mutable",
2696 ImmBorrow => "immutable",
2697 UniqueImmBorrow => "uniquely immutable",
2702 #[derive(Debug, Clone)]
2703 pub enum Attributes<'tcx> {
2704 Owned(Lrc<[ast::Attribute]>),
2705 Borrowed(&'tcx [ast::Attribute]),
2708 impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
2709 type Target = [ast::Attribute];
2711 fn deref(&self) -> &[ast::Attribute] {
2713 &Attributes::Owned(ref data) => &data,
2714 &Attributes::Borrowed(data) => data
2719 #[derive(Debug, PartialEq, Eq)]
2720 pub enum ImplOverlapKind {
2721 /// These impls are always allowed to overlap.
2723 /// These impls are allowed to overlap, but that raises
2724 /// an issue #33140 future-compatibility warning.
2726 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2727 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2729 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2730 /// that difference, making what reduces to the following set of impls:
2734 /// impl Trait for dyn Send + Sync {}
2735 /// impl Trait for dyn Sync + Send {}
2738 /// Obviously, once we made these types be identical, that code causes a coherence
2739 /// error and a fairly big headache for us. However, luckily for us, the trait
2740 /// `Trait` used in this case is basically a marker trait, and therefore having
2741 /// overlapping impls for it is sound.
2743 /// To handle this, we basically regard the trait as a marker trait, with an additional
2744 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2745 /// it has the following restrictions:
2747 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2749 /// 2. The trait-ref of both impls must be equal.
2750 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2752 /// 4. Neither of the impls can have any where-clauses.
2754 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2758 impl<'tcx> TyCtxt<'tcx> {
2759 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
2760 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2763 /// Returns an iterator of the `DefId`s for all body-owners in this
2764 /// crate. If you would prefer to iterate over the bodies
2765 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2766 pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
2770 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2773 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2774 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2775 f(self.hir().body_owner_def_id(body_id))
2779 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
2780 self.associated_items(id)
2781 .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
2785 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2786 self.associated_items(did).any(|item| {
2787 item.relevant_for_never()
2791 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
2792 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2793 match self.hir().get(hir_id) {
2794 Node::TraitItem(_) | Node::ImplItem(_) => true,
2798 match self.def_kind(def_id).expect("no def for def-id") {
2801 | DefKind::AssocTy => true,
2806 if is_associated_item {
2807 Some(self.associated_item(def_id))
2813 fn associated_item_from_trait_item_ref(self,
2814 parent_def_id: DefId,
2815 parent_vis: &hir::Visibility,
2816 trait_item_ref: &hir::TraitItemRef)
2818 let def_id = self.hir().local_def_id_from_hir_id(trait_item_ref.id.hir_id);
2819 let (kind, has_self) = match trait_item_ref.kind {
2820 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2821 hir::AssocItemKind::Method { has_self } => {
2822 (ty::AssocKind::Method, has_self)
2824 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2825 hir::AssocItemKind::Existential => bug!("only impls can have existentials"),
2829 ident: trait_item_ref.ident,
2831 // Visibility of trait items is inherited from their traits.
2832 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2833 defaultness: trait_item_ref.defaultness,
2835 container: TraitContainer(parent_def_id),
2836 method_has_self_argument: has_self
2840 fn associated_item_from_impl_item_ref(self,
2841 parent_def_id: DefId,
2842 impl_item_ref: &hir::ImplItemRef)
2844 let def_id = self.hir().local_def_id_from_hir_id(impl_item_ref.id.hir_id);
2845 let (kind, has_self) = match impl_item_ref.kind {
2846 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2847 hir::AssocItemKind::Method { has_self } => {
2848 (ty::AssocKind::Method, has_self)
2850 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2851 hir::AssocItemKind::Existential => (ty::AssocKind::Existential, false),
2855 ident: impl_item_ref.ident,
2857 // Visibility of trait impl items doesn't matter.
2858 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2859 defaultness: impl_item_ref.defaultness,
2861 container: ImplContainer(parent_def_id),
2862 method_has_self_argument: has_self
2866 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2867 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2870 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2871 variant.fields.iter().position(|field| {
2872 self.hygienic_eq(ident, field.ident, variant.def_id)
2876 pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
2877 // Ideally, we would use `-> impl Iterator` here, but it falls
2878 // afoul of the conservative "capture [restrictions]" we put
2879 // in place, so we use a hand-written iterator.
2881 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2882 AssocItemsIterator {
2884 def_ids: self.associated_item_def_ids(def_id),
2889 /// Returns `true` if the impls are the same polarity and the trait either
2890 /// has no items or is annotated #[marker] and prevents item overrides.
2891 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2892 -> Option<ImplOverlapKind>
2894 let is_legit = if self.features().overlapping_marker_traits {
2895 let trait1_is_empty = self.impl_trait_ref(def_id1)
2896 .map_or(false, |trait_ref| {
2897 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2899 let trait2_is_empty = self.impl_trait_ref(def_id2)
2900 .map_or(false, |trait_ref| {
2901 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2903 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2907 let is_marker_impl = |def_id: DefId| -> bool {
2908 let trait_ref = self.impl_trait_ref(def_id);
2909 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2911 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2912 && is_marker_impl(def_id1)
2913 && is_marker_impl(def_id2)
2917 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
2919 Some(ImplOverlapKind::Permitted)
2921 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2922 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2923 if self_ty1 == self_ty2 {
2924 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2926 return Some(ImplOverlapKind::Issue33140);
2928 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2929 def_id1, def_id2, self_ty1, self_ty2);
2934 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2940 /// Returns `ty::VariantDef` if `res` refers to a struct,
2941 /// or variant or their constructors, panics otherwise.
2942 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2944 Res::Def(DefKind::Variant, did) => {
2945 let enum_did = self.parent(did).unwrap();
2946 self.adt_def(enum_did).variant_with_id(did)
2948 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
2949 self.adt_def(did).non_enum_variant()
2951 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2952 let variant_did = self.parent(variant_ctor_did).unwrap();
2953 let enum_did = self.parent(variant_did).unwrap();
2954 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2956 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2957 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2958 self.adt_def(struct_did).non_enum_variant()
2960 _ => bug!("expect_variant_res used with unexpected res {:?}", res)
2964 pub fn item_name(self, id: DefId) -> Symbol {
2965 if id.index == CRATE_DEF_INDEX {
2966 self.original_crate_name(id.krate)
2968 let def_key = self.def_key(id);
2969 match def_key.disambiguated_data.data {
2970 // The name of a constructor is that of its parent.
2971 hir_map::DefPathData::Ctor =>
2972 self.item_name(DefId {
2974 index: def_key.parent.unwrap()
2976 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2977 bug!("item_name: no name for {:?}", self.def_path(id));
2983 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2984 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> &'tcx Body<'tcx> {
2986 ty::InstanceDef::Item(did) => {
2987 self.optimized_mir(did)
2989 ty::InstanceDef::VtableShim(..) |
2990 ty::InstanceDef::Intrinsic(..) |
2991 ty::InstanceDef::FnPtrShim(..) |
2992 ty::InstanceDef::Virtual(..) |
2993 ty::InstanceDef::ClosureOnceShim { .. } |
2994 ty::InstanceDef::DropGlue(..) |
2995 ty::InstanceDef::CloneShim(..) => {
2996 self.mir_shims(instance)
3001 /// Gets the attributes of a definition.
3002 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
3003 if let Some(id) = self.hir().as_local_hir_id(did) {
3004 Attributes::Borrowed(self.hir().attrs(id))
3006 Attributes::Owned(self.item_attrs(did))
3010 /// Determines whether an item is annotated with an attribute.
3011 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
3012 attr::contains_name(&self.get_attrs(did), attr)
3015 /// Returns `true` if this is an `auto trait`.
3016 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
3017 self.trait_def(trait_def_id).has_auto_impl
3020 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
3021 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
3024 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
3025 /// If it implements no trait, returns `None`.
3026 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
3027 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
3030 /// If the given defid describes a method belonging to an impl, returns the
3031 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
3032 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
3033 let item = if def_id.krate != LOCAL_CRATE {
3034 if let Some(DefKind::Method) = self.def_kind(def_id) {
3035 Some(self.associated_item(def_id))
3040 self.opt_associated_item(def_id)
3043 item.and_then(|trait_item|
3044 match trait_item.container {
3045 TraitContainer(_) => None,
3046 ImplContainer(def_id) => Some(def_id),
3051 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3052 /// with the name of the crate containing the impl.
3053 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3054 if impl_did.is_local() {
3055 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3056 Ok(self.hir().span(hir_id))
3058 Err(self.crate_name(impl_did.krate))
3062 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3063 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3064 /// definition's parent/scope to perform comparison.
3065 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3066 // We could use `Ident::eq` here, but we deliberately don't. The name
3067 // comparison fails frequently, and we want to avoid the expensive
3068 // `modern()` calls required for the span comparison whenever possible.
3069 use_name.name == def_name.name &&
3070 use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
3071 self.expansion_that_defined(def_parent_def_id))
3074 fn expansion_that_defined(self, scope: DefId) -> Mark {
3076 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3081 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
3082 ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
3086 pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
3088 let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
3089 Some(actual_expansion) =>
3090 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3091 None => self.hir().get_module_parent(block),
3097 pub struct AssocItemsIterator<'tcx> {
3099 def_ids: &'tcx [DefId],
3103 impl Iterator for AssocItemsIterator<'_> {
3104 type Item = AssocItem;
3106 fn next(&mut self) -> Option<AssocItem> {
3107 let def_id = self.def_ids.get(self.next_index)?;
3108 self.next_index += 1;
3109 Some(self.tcx.associated_item(*def_id))
3113 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
3114 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3115 let parent_id = tcx.hir().get_parent_item(id);
3116 let parent_def_id = tcx.hir().local_def_id_from_hir_id(parent_id);
3117 let parent_item = tcx.hir().expect_item(parent_id);
3118 match parent_item.node {
3119 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3120 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3121 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3123 debug_assert_eq!(assoc_item.def_id, def_id);
3128 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3129 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3130 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3133 debug_assert_eq!(assoc_item.def_id, def_id);
3141 span_bug!(parent_item.span,
3142 "unexpected parent of trait or impl item or item not found: {:?}",
3146 #[derive(Clone, HashStable)]
3147 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3149 /// Calculates the `Sized` constraint.
3151 /// In fact, there are only a few options for the types in the constraint:
3152 /// - an obviously-unsized type
3153 /// - a type parameter or projection whose Sizedness can't be known
3154 /// - a tuple of type parameters or projections, if there are multiple
3156 /// - a Error, if a type contained itself. The representability
3157 /// check should catch this case.
3158 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
3159 let def = tcx.adt_def(def_id);
3161 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3164 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3167 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3169 AdtSizedConstraint(result)
3172 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
3173 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3174 let item = tcx.hir().expect_item(id);
3176 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3177 tcx.arena.alloc_from_iter(
3178 trait_item_refs.iter()
3179 .map(|trait_item_ref| trait_item_ref.id)
3180 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3183 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3184 tcx.arena.alloc_from_iter(
3185 impl_item_refs.iter()
3186 .map(|impl_item_ref| impl_item_ref.id)
3187 .map(|id| tcx.hir().local_def_id_from_hir_id(id.hir_id))
3190 hir::ItemKind::TraitAlias(..) => &[],
3191 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3195 fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
3196 tcx.hir().span_if_local(def_id).unwrap()
3199 /// If the given `DefId` describes an item belonging to a trait,
3200 /// returns the `DefId` of the trait that the trait item belongs to;
3201 /// otherwise, returns `None`.
3202 fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3203 tcx.opt_associated_item(def_id)
3204 .and_then(|associated_item| {
3205 match associated_item.container {
3206 TraitContainer(def_id) => Some(def_id),
3207 ImplContainer(_) => None
3212 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3213 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3214 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3215 if let Node::Item(item) = tcx.hir().get(hir_id) {
3216 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3217 return exist_ty.impl_trait_fn;
3224 /// See `ParamEnv` struct definition for details.
3225 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
3226 // The param_env of an impl Trait type is its defining function's param_env
3227 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3228 return param_env(tcx, parent);
3230 // Compute the bounds on Self and the type parameters.
3232 let InstantiatedPredicates { predicates } =
3233 tcx.predicates_of(def_id).instantiate_identity(tcx);
3235 // Finally, we have to normalize the bounds in the environment, in
3236 // case they contain any associated type projections. This process
3237 // can yield errors if the put in illegal associated types, like
3238 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3239 // report these errors right here; this doesn't actually feel
3240 // right to me, because constructing the environment feels like a
3241 // kind of a "idempotent" action, but I'm not sure where would be
3242 // a better place. In practice, we construct environments for
3243 // every fn once during type checking, and we'll abort if there
3244 // are any errors at that point, so after type checking you can be
3245 // sure that this will succeed without errors anyway.
3247 let unnormalized_env = ty::ParamEnv::new(
3248 tcx.intern_predicates(&predicates),
3249 traits::Reveal::UserFacing,
3250 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3253 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3254 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
3256 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3257 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3260 fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
3261 assert_eq!(crate_num, LOCAL_CRATE);
3262 tcx.sess.local_crate_disambiguator()
3265 fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
3266 assert_eq!(crate_num, LOCAL_CRATE);
3267 tcx.crate_name.clone()
3270 fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
3271 assert_eq!(crate_num, LOCAL_CRATE);
3272 tcx.hir().crate_hash
3275 fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
3276 match instance_def {
3277 InstanceDef::Item(..) |
3278 InstanceDef::DropGlue(..) => {
3279 let mir = tcx.instance_mir(instance_def);
3280 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3282 // Estimate the size of other compiler-generated shims to be 1.
3287 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3289 /// See [`ImplOverlapKind::Issue33140`] for more details.
3290 fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
3291 debug!("issue33140_self_ty({:?})", def_id);
3293 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3294 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3297 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3299 let is_marker_like =
3300 tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
3301 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3303 // Check whether these impls would be ok for a marker trait.
3304 if !is_marker_like {
3305 debug!("issue33140_self_ty - not marker-like!");
3309 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3310 if trait_ref.substs.len() != 1 {
3311 debug!("issue33140_self_ty - impl has substs!");
3315 let predicates = tcx.predicates_of(def_id);
3316 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3317 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3321 let self_ty = trait_ref.self_ty();
3322 let self_ty_matches = match self_ty.sty {
3323 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3327 if self_ty_matches {
3328 debug!("issue33140_self_ty - MATCHES!");
3331 debug!("issue33140_self_ty - non-matching self type");
3336 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3337 context::provide(providers);
3338 erase_regions::provide(providers);
3339 layout::provide(providers);
3340 util::provide(providers);
3341 constness::provide(providers);
3342 *providers = ty::query::Providers {
3344 associated_item_def_ids,
3345 adt_sized_constraint,
3349 crate_disambiguator,
3350 original_crate_name,
3352 trait_impls_of: trait_def::trait_impls_of_provider,
3353 instance_def_size_estimate,
3359 /// A map for the local crate mapping each type to a vector of its
3360 /// inherent impls. This is not meant to be used outside of coherence;
3361 /// rather, you should request the vector for a specific type via
3362 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3363 /// (constructing this map requires touching the entire crate).
3364 #[derive(Clone, Debug, Default, HashStable)]
3365 pub struct CrateInherentImpls {
3366 pub inherent_impls: DefIdMap<Vec<DefId>>,
3369 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3370 pub struct SymbolName {
3371 // FIXME: we don't rely on interning or equality here - better have
3372 // this be a `&'tcx str`.
3373 pub name: InternedString
3376 impl_stable_hash_for!(struct self::SymbolName {
3381 pub fn new(name: &str) -> SymbolName {
3383 name: InternedString::intern(name)
3387 pub fn as_str(&self) -> LocalInternedString {
3392 impl fmt::Display for SymbolName {
3393 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3394 fmt::Display::fmt(&self.name, fmt)
3398 impl fmt::Debug for SymbolName {
3399 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3400 fmt::Display::fmt(&self.name, fmt)