1 // ignore-tidy-filelength
3 pub use self::fold::{TypeFoldable, TypeVisitor};
4 pub use self::AssocItemContainer::*;
5 pub use self::BorrowKind::*;
6 pub use self::IntVarValue::*;
7 pub use self::Variance::*;
9 use crate::hir::def::{CtorKind, CtorOf, DefKind, ExportMap, Res};
10 use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
12 use crate::hir::{map as hir_map, GlobMap, TraitMap};
13 use crate::ich::Fingerprint;
14 use crate::ich::StableHashingContext;
15 use crate::infer::canonical::Canonical;
16 use crate::middle::cstore::CrateStoreDyn;
17 use crate::middle::lang_items::{FnMutTraitLangItem, FnOnceTraitLangItem, FnTraitLangItem};
18 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
19 use crate::mir::interpret::ErrorHandled;
20 use crate::mir::GeneratorLayout;
21 use crate::mir::ReadOnlyBodyAndCache;
22 use crate::session::CrateDisambiguator;
23 use crate::session::DataTypeKind;
24 use crate::traits::{self, Reveal};
26 use crate::ty::layout::VariantIdx;
27 use crate::ty::subst::{InternalSubsts, Subst, SubstsRef};
28 use crate::ty::util::{Discr, IntTypeExt};
29 use crate::ty::walk::TypeWalker;
30 use crate::util::captures::Captures;
31 use crate::util::nodemap::{DefIdMap, FxHashMap, NodeMap, NodeSet};
32 use arena::SyncDroplessArena;
33 use rustc_data_structures::svh::Svh;
34 use rustc_macros::HashStable;
36 use rustc_data_structures::sync::{self, par_iter, Lrc, ParallelIterator};
37 use rustc_serialize::{self, Encodable, Encoder};
38 use rustc_target::abi::Align;
39 use std::cell::RefCell;
40 use std::cmp::{self, Ordering};
42 use std::hash::{Hash, Hasher};
47 use syntax::ast::{self, Ident, Name, NodeId};
49 use syntax_pos::hygiene::ExpnId;
50 use syntax_pos::symbol::{kw, sym, Symbol};
53 use rustc_data_structures::fx::FxIndexMap;
54 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
55 use rustc_index::vec::{Idx, IndexVec};
60 pub use self::sty::BoundRegion::*;
61 pub use self::sty::InferTy::*;
62 pub use self::sty::RegionKind;
63 pub use self::sty::RegionKind::*;
64 pub use self::sty::TyKind::*;
65 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
66 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
67 pub use self::sty::{CanonicalPolyFnSig, FnSig, GenSig, PolyFnSig, PolyGenSig};
68 pub use self::sty::{ClosureSubsts, GeneratorSubsts, TypeAndMut, UpvarSubsts};
69 pub use self::sty::{Const, ConstKind, ExistentialProjection, PolyExistentialProjection};
70 pub use self::sty::{ConstVid, FloatVid, IntVid, RegionVid, TyVid};
71 pub use self::sty::{ExistentialPredicate, InferConst, InferTy, ParamConst, ParamTy, ProjectionTy};
72 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
73 pub use self::sty::{PolyTraitRef, TraitRef, TyKind};
74 pub use crate::ty::diagnostics::*;
76 pub use self::binding::BindingMode;
77 pub use self::binding::BindingMode::*;
79 pub use self::context::{keep_local, tls, AllArenas, FreeRegionInfo, TyCtxt};
80 pub use self::context::{
81 CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
82 UserType, UserTypeAnnotationIndex,
84 pub use self::context::{
85 CtxtInterners, GeneratorInteriorTypeCause, GlobalCtxt, Lift, TypeckTables,
88 pub use self::instance::{Instance, InstanceDef};
90 pub use self::structural_match::search_for_structural_match_violation;
91 pub use self::structural_match::type_marked_structural;
92 pub use self::structural_match::NonStructuralMatchTy;
94 pub use self::trait_def::TraitDef;
96 pub use self::query::queries;
110 pub mod inhabitedness;
126 mod structural_impls;
127 mod structural_match;
132 pub struct ResolverOutputs {
133 pub definitions: hir_map::Definitions,
134 pub cstore: Box<CrateStoreDyn>,
135 pub extern_crate_map: NodeMap<CrateNum>,
136 pub trait_map: TraitMap,
137 pub maybe_unused_trait_imports: NodeSet,
138 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
139 pub export_map: ExportMap<NodeId>,
140 pub glob_map: GlobMap,
141 /// Extern prelude entries. The value is `true` if the entry was introduced
142 /// via `extern crate` item and not `--extern` option or compiler built-in.
143 pub extern_prelude: FxHashMap<Name, bool>,
146 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
147 pub enum AssocItemContainer {
148 TraitContainer(DefId),
149 ImplContainer(DefId),
152 impl AssocItemContainer {
153 /// Asserts that this is the `DefId` of an associated item declared
154 /// in a trait, and returns the trait `DefId`.
155 pub fn assert_trait(&self) -> DefId {
157 TraitContainer(id) => id,
158 _ => bug!("associated item has wrong container type: {:?}", self),
162 pub fn id(&self) -> DefId {
164 TraitContainer(id) => id,
165 ImplContainer(id) => id,
170 /// The "header" of an impl is everything outside the body: a Self type, a trait
171 /// ref (in the case of a trait impl), and a set of predicates (from the
172 /// bounds / where-clauses).
173 #[derive(Clone, Debug, TypeFoldable)]
174 pub struct ImplHeader<'tcx> {
175 pub impl_def_id: DefId,
176 pub self_ty: Ty<'tcx>,
177 pub trait_ref: Option<TraitRef<'tcx>>,
178 pub predicates: Vec<Predicate<'tcx>>,
181 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
182 pub enum ImplPolarity {
183 /// `impl Trait for Type`
185 /// `impl !Trait for Type`
187 /// `#[rustc_reservation_impl] impl Trait for Type`
189 /// This is a "stability hack", not a real Rust feature.
190 /// See #64631 for details.
194 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
195 pub struct AssocItem {
197 #[stable_hasher(project(name))]
201 pub defaultness: hir::Defaultness,
202 pub container: AssocItemContainer,
204 /// Whether this is a method with an explicit self
205 /// as its first argument, allowing method calls.
206 pub method_has_self_argument: bool,
209 #[derive(Copy, Clone, PartialEq, Debug, HashStable)]
218 pub fn suggestion_descr(&self) -> &'static str {
220 ty::AssocKind::Method => "method call",
221 ty::AssocKind::Type | ty::AssocKind::OpaqueTy => "associated type",
222 ty::AssocKind::Const => "associated constant",
228 pub fn def_kind(&self) -> DefKind {
230 AssocKind::Const => DefKind::AssocConst,
231 AssocKind::Method => DefKind::Method,
232 AssocKind::Type => DefKind::AssocTy,
233 AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
237 /// Tests whether the associated item admits a non-trivial implementation
239 pub fn relevant_for_never(&self) -> bool {
241 AssocKind::OpaqueTy | AssocKind::Const | AssocKind::Type => true,
242 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
243 AssocKind::Method => !self.method_has_self_argument,
247 pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
249 ty::AssocKind::Method => {
250 // We skip the binder here because the binder would deanonymize all
251 // late-bound regions, and we don't want method signatures to show up
252 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
253 // regions just fine, showing `fn(&MyType)`.
254 tcx.fn_sig(self.def_id).skip_binder().to_string()
256 ty::AssocKind::Type => format!("type {};", self.ident),
257 // FIXME(type_alias_impl_trait): we should print bounds here too.
258 ty::AssocKind::OpaqueTy => format!("type {};", self.ident),
259 ty::AssocKind::Const => {
260 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
266 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
267 pub enum Visibility {
268 /// Visible everywhere (including in other crates).
270 /// Visible only in the given crate-local module.
272 /// Not visible anywhere in the local crate. This is the visibility of private external items.
276 pub trait DefIdTree: Copy {
277 fn parent(self, id: DefId) -> Option<DefId>;
279 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
280 if descendant.krate != ancestor.krate {
284 while descendant != ancestor {
285 match self.parent(descendant) {
286 Some(parent) => descendant = parent,
287 None => return false,
294 impl<'tcx> DefIdTree for TyCtxt<'tcx> {
295 fn parent(self, id: DefId) -> Option<DefId> {
296 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
301 pub fn from_hir(visibility: &hir::Visibility<'_>, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
302 match visibility.node {
303 hir::VisibilityKind::Public => Visibility::Public,
304 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
305 hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
306 // If there is no resolution, `resolve` will have already reported an error, so
307 // assume that the visibility is public to avoid reporting more privacy errors.
308 Res::Err => Visibility::Public,
309 def => Visibility::Restricted(def.def_id()),
311 hir::VisibilityKind::Inherited => {
312 Visibility::Restricted(tcx.hir().get_module_parent(id))
317 /// Returns `true` if an item with this visibility is accessible from the given block.
318 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
319 let restriction = match self {
320 // Public items are visible everywhere.
321 Visibility::Public => return true,
322 // Private items from other crates are visible nowhere.
323 Visibility::Invisible => return false,
324 // Restricted items are visible in an arbitrary local module.
325 Visibility::Restricted(other) if other.krate != module.krate => return false,
326 Visibility::Restricted(module) => module,
329 tree.is_descendant_of(module, restriction)
332 /// Returns `true` if this visibility is at least as accessible as the given visibility
333 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
334 let vis_restriction = match vis {
335 Visibility::Public => return self == Visibility::Public,
336 Visibility::Invisible => return true,
337 Visibility::Restricted(module) => module,
340 self.is_accessible_from(vis_restriction, tree)
343 // Returns `true` if this item is visible anywhere in the local crate.
344 pub fn is_visible_locally(self) -> bool {
346 Visibility::Public => true,
347 Visibility::Restricted(def_id) => def_id.is_local(),
348 Visibility::Invisible => false,
353 #[derive(Copy, Clone, PartialEq, RustcDecodable, RustcEncodable, HashStable)]
355 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
356 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
357 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
358 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
361 /// The crate variances map is computed during typeck and contains the
362 /// variance of every item in the local crate. You should not use it
363 /// directly, because to do so will make your pass dependent on the
364 /// HIR of every item in the local crate. Instead, use
365 /// `tcx.variances_of()` to get the variance for a *particular*
367 #[derive(HashStable)]
368 pub struct CrateVariancesMap<'tcx> {
369 /// For each item with generics, maps to a vector of the variance
370 /// of its generics. If an item has no generics, it will have no
372 pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
376 /// `a.xform(b)` combines the variance of a context with the
377 /// variance of a type with the following meaning. If we are in a
378 /// context with variance `a`, and we encounter a type argument in
379 /// a position with variance `b`, then `a.xform(b)` is the new
380 /// variance with which the argument appears.
386 /// Here, the "ambient" variance starts as covariant. `*mut T` is
387 /// invariant with respect to `T`, so the variance in which the
388 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
389 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
390 /// respect to its type argument `T`, and hence the variance of
391 /// the `i32` here is `Invariant.xform(Covariant)`, which results
392 /// (again) in `Invariant`.
396 /// fn(*const Vec<i32>, *mut Vec<i32)
398 /// The ambient variance is covariant. A `fn` type is
399 /// contravariant with respect to its parameters, so the variance
400 /// within which both pointer types appear is
401 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
402 /// T` is covariant with respect to `T`, so the variance within
403 /// which the first `Vec<i32>` appears is
404 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
405 /// is true for its `i32` argument. In the `*mut T` case, the
406 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
407 /// and hence the outermost type is `Invariant` with respect to
408 /// `Vec<i32>` (and its `i32` argument).
410 /// Source: Figure 1 of "Taming the Wildcards:
411 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
412 pub fn xform(self, v: ty::Variance) -> ty::Variance {
414 // Figure 1, column 1.
415 (ty::Covariant, ty::Covariant) => ty::Covariant,
416 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
417 (ty::Covariant, ty::Invariant) => ty::Invariant,
418 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
420 // Figure 1, column 2.
421 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
422 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
423 (ty::Contravariant, ty::Invariant) => ty::Invariant,
424 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
426 // Figure 1, column 3.
427 (ty::Invariant, _) => ty::Invariant,
429 // Figure 1, column 4.
430 (ty::Bivariant, _) => ty::Bivariant,
435 // Contains information needed to resolve types and (in the future) look up
436 // the types of AST nodes.
437 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
438 pub struct CReaderCacheKey {
443 // Flags that we track on types. These flags are propagated upwards
444 // through the type during type construction, so that we can quickly
445 // check whether the type has various kinds of types in it without
446 // recursing over the type itself.
448 pub struct TypeFlags: u32 {
449 const HAS_PARAMS = 1 << 0;
450 const HAS_TY_INFER = 1 << 1;
451 const HAS_RE_INFER = 1 << 2;
452 const HAS_RE_PLACEHOLDER = 1 << 3;
454 /// Does this have any `ReEarlyBound` regions? Used to
455 /// determine whether substitition is required, since those
456 /// represent regions that are bound in a `ty::Generics` and
457 /// hence may be substituted.
458 const HAS_RE_EARLY_BOUND = 1 << 4;
460 /// Does this have any region that "appears free" in the type?
461 /// Basically anything but `ReLateBound` and `ReErased`.
462 const HAS_FREE_REGIONS = 1 << 5;
464 /// Is an error type reachable?
465 const HAS_TY_ERR = 1 << 6;
466 const HAS_PROJECTION = 1 << 7;
468 // FIXME: Rename this to the actual property since it's used for generators too
469 const HAS_TY_CLOSURE = 1 << 8;
471 /// `true` if there are "names" of types and regions and so forth
472 /// that are local to a particular fn
473 const HAS_FREE_LOCAL_NAMES = 1 << 9;
475 /// Present if the type belongs in a local type context.
476 /// Only set for Infer other than Fresh.
477 const KEEP_IN_LOCAL_TCX = 1 << 10;
479 /// Does this have any `ReLateBound` regions? Used to check
480 /// if a global bound is safe to evaluate.
481 const HAS_RE_LATE_BOUND = 1 << 11;
483 const HAS_TY_PLACEHOLDER = 1 << 12;
485 const HAS_CT_INFER = 1 << 13;
486 const HAS_CT_PLACEHOLDER = 1 << 14;
488 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
489 TypeFlags::HAS_RE_EARLY_BOUND.bits;
491 /// Flags representing the nominal content of a type,
492 /// computed by FlagsComputation. If you add a new nominal
493 /// flag, it should be added here too.
494 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
495 TypeFlags::HAS_TY_INFER.bits |
496 TypeFlags::HAS_RE_INFER.bits |
497 TypeFlags::HAS_RE_PLACEHOLDER.bits |
498 TypeFlags::HAS_RE_EARLY_BOUND.bits |
499 TypeFlags::HAS_FREE_REGIONS.bits |
500 TypeFlags::HAS_TY_ERR.bits |
501 TypeFlags::HAS_PROJECTION.bits |
502 TypeFlags::HAS_TY_CLOSURE.bits |
503 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
504 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
505 TypeFlags::HAS_RE_LATE_BOUND.bits |
506 TypeFlags::HAS_TY_PLACEHOLDER.bits |
507 TypeFlags::HAS_CT_INFER.bits |
508 TypeFlags::HAS_CT_PLACEHOLDER.bits;
512 #[allow(rustc::usage_of_ty_tykind)]
513 pub struct TyS<'tcx> {
514 pub kind: TyKind<'tcx>,
515 pub flags: TypeFlags,
517 /// This is a kind of confusing thing: it stores the smallest
520 /// (a) the binder itself captures nothing but
521 /// (b) all the late-bound things within the type are captured
522 /// by some sub-binder.
524 /// So, for a type without any late-bound things, like `u32`, this
525 /// will be *innermost*, because that is the innermost binder that
526 /// captures nothing. But for a type `&'D u32`, where `'D` is a
527 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
528 /// -- the binder itself does not capture `D`, but `D` is captured
529 /// by an inner binder.
531 /// We call this concept an "exclusive" binder `D` because all
532 /// De Bruijn indices within the type are contained within `0..D`
534 outer_exclusive_binder: ty::DebruijnIndex,
537 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
538 #[cfg(target_arch = "x86_64")]
539 static_assert_size!(TyS<'_>, 32);
541 impl<'tcx> Ord for TyS<'tcx> {
542 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
543 self.kind.cmp(&other.kind)
547 impl<'tcx> PartialOrd for TyS<'tcx> {
548 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
549 Some(self.kind.cmp(&other.kind))
553 impl<'tcx> PartialEq for TyS<'tcx> {
555 fn eq(&self, other: &TyS<'tcx>) -> bool {
559 impl<'tcx> Eq for TyS<'tcx> {}
561 impl<'tcx> Hash for TyS<'tcx> {
562 fn hash<H: Hasher>(&self, s: &mut H) {
563 (self as *const TyS<'_>).hash(s)
567 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
568 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
572 // The other fields just provide fast access to information that is
573 // also contained in `kind`, so no need to hash them.
576 outer_exclusive_binder: _,
579 kind.hash_stable(hcx, hasher);
583 #[rustc_diagnostic_item = "Ty"]
584 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
586 impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {}
587 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {}
589 pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
592 /// A dummy type used to force `List` to be unsized while not requiring references to it be wide
594 type OpaqueListContents;
597 /// A wrapper for slices with the additional invariant
598 /// that the slice is interned and no other slice with
599 /// the same contents can exist in the same context.
600 /// This means we can use pointer for both
601 /// equality comparisons and hashing.
602 /// Note: `Slice` was already taken by the `Ty`.
607 opaque: OpaqueListContents,
610 unsafe impl<T: Sync> Sync for List<T> {}
612 impl<T: Copy> List<T> {
614 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
615 assert!(!mem::needs_drop::<T>());
616 assert!(mem::size_of::<T>() != 0);
617 assert!(slice.len() != 0);
619 // Align up the size of the len (usize) field
620 let align = mem::align_of::<T>();
621 let align_mask = align - 1;
622 let offset = mem::size_of::<usize>();
623 let offset = (offset + align_mask) & !align_mask;
625 let size = offset + slice.len() * mem::size_of::<T>();
627 let mem = arena.alloc_raw(size, cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
629 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
631 result.len = slice.len();
633 // Write the elements
634 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
635 arena_slice.copy_from_slice(slice);
642 impl<T: fmt::Debug> fmt::Debug for List<T> {
643 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
648 impl<T: Encodable> Encodable for List<T> {
650 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
655 impl<T> Ord for List<T>
659 fn cmp(&self, other: &List<T>) -> Ordering {
660 if self == other { Ordering::Equal } else { <[T] as Ord>::cmp(&**self, &**other) }
664 impl<T> PartialOrd for List<T>
668 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
670 Some(Ordering::Equal)
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] {
700 impl<T> AsRef<[T]> for List<T> {
702 fn as_ref(&self) -> &[T] {
703 unsafe { slice::from_raw_parts(self.data.as_ptr(), self.len) }
707 impl<'a, T> IntoIterator for &'a List<T> {
709 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
711 fn into_iter(self) -> Self::IntoIter {
716 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
720 pub fn empty<'a>() -> &'a List<T> {
721 #[repr(align(64), C)]
722 struct EmptySlice([u8; 64]);
723 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
724 assert!(mem::align_of::<T>() <= 64);
725 unsafe { &*(&EMPTY_SLICE as *const _ as *const List<T>) }
729 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
730 pub struct UpvarPath {
731 pub hir_id: hir::HirId,
734 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
735 /// the original var ID (that is, the root variable that is referenced
736 /// by the upvar) and the ID of the closure expression.
737 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
739 pub var_path: UpvarPath,
740 pub closure_expr_id: LocalDefId,
743 #[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
744 pub enum BorrowKind {
745 /// Data must be immutable and is aliasable.
748 /// Data must be immutable but not aliasable. This kind of borrow
749 /// cannot currently be expressed by the user and is used only in
750 /// implicit closure bindings. It is needed when the closure
751 /// is borrowing or mutating a mutable referent, e.g.:
753 /// let x: &mut isize = ...;
754 /// let y = || *x += 5;
756 /// If we were to try to translate this closure into a more explicit
757 /// form, we'd encounter an error with the code as written:
759 /// struct Env { x: & &mut isize }
760 /// let x: &mut isize = ...;
761 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
762 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
764 /// This is then illegal because you cannot mutate a `&mut` found
765 /// in an aliasable location. To solve, you'd have to translate with
766 /// an `&mut` borrow:
768 /// struct Env { x: & &mut isize }
769 /// let x: &mut isize = ...;
770 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
771 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
773 /// Now the assignment to `**env.x` is legal, but creating a
774 /// mutable pointer to `x` is not because `x` is not mutable. We
775 /// could fix this by declaring `x` as `let mut x`. This is ok in
776 /// user code, if awkward, but extra weird for closures, since the
777 /// borrow is hidden.
779 /// So we introduce a "unique imm" borrow -- the referent is
780 /// immutable, but not aliasable. This solves the problem. For
781 /// simplicity, we don't give users the way to express this
782 /// borrow, it's just used when translating closures.
785 /// Data is mutable and not aliasable.
789 /// Information describing the capture of an upvar. This is computed
790 /// during `typeck`, specifically by `regionck`.
791 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
792 pub enum UpvarCapture<'tcx> {
793 /// Upvar is captured by value. This is always true when the
794 /// closure is labeled `move`, but can also be true in other cases
795 /// depending on inference.
798 /// Upvar is captured by reference.
799 ByRef(UpvarBorrow<'tcx>),
802 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
803 pub struct UpvarBorrow<'tcx> {
804 /// The kind of borrow: by-ref upvars have access to shared
805 /// immutable borrows, which are not part of the normal language
807 pub kind: BorrowKind,
809 /// Region of the resulting reference.
810 pub region: ty::Region<'tcx>,
813 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
814 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
816 #[derive(Copy, Clone, TypeFoldable)]
817 pub struct ClosureUpvar<'tcx> {
823 #[derive(Clone, Copy, PartialEq, Eq)]
824 pub enum IntVarValue {
826 UintType(ast::UintTy),
829 #[derive(Clone, Copy, PartialEq, Eq)]
830 pub struct FloatVarValue(pub ast::FloatTy);
832 impl ty::EarlyBoundRegion {
833 pub fn to_bound_region(&self) -> ty::BoundRegion {
834 ty::BoundRegion::BrNamed(self.def_id, self.name)
837 /// Does this early bound region have a name? Early bound regions normally
838 /// always have names except when using anonymous lifetimes (`'_`).
839 pub fn has_name(&self) -> bool {
840 self.name != kw::UnderscoreLifetime
844 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
845 pub enum GenericParamDefKind {
849 object_lifetime_default: ObjectLifetimeDefault,
850 synthetic: Option<hir::SyntheticTyParamKind>,
855 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
856 pub struct GenericParamDef {
861 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
862 /// on generic parameter `'a`/`T`, asserts data behind the parameter
863 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
864 pub pure_wrt_drop: bool,
866 pub kind: GenericParamDefKind,
869 impl GenericParamDef {
870 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
871 if let GenericParamDefKind::Lifetime = self.kind {
872 ty::EarlyBoundRegion { def_id: self.def_id, index: self.index, name: self.name }
874 bug!("cannot convert a non-lifetime parameter def to an early bound region")
878 pub fn to_bound_region(&self) -> ty::BoundRegion {
879 if let GenericParamDefKind::Lifetime = self.kind {
880 self.to_early_bound_region_data().to_bound_region()
882 bug!("cannot convert a non-lifetime parameter def to an early bound region")
888 pub struct GenericParamCount {
889 pub lifetimes: usize,
894 /// Information about the formal type/lifetime parameters associated
895 /// with an item or method. Analogous to `hir::Generics`.
897 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
898 /// `Self` (optionally), `Lifetime` params..., `Type` params...
899 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
900 pub struct Generics {
901 pub parent: Option<DefId>,
902 pub parent_count: usize,
903 pub params: Vec<GenericParamDef>,
905 /// Reverse map to the `index` field of each `GenericParamDef`.
906 #[stable_hasher(ignore)]
907 pub param_def_id_to_index: FxHashMap<DefId, u32>,
910 pub has_late_bound_regions: Option<Span>,
913 impl<'tcx> Generics {
914 pub fn count(&self) -> usize {
915 self.parent_count + self.params.len()
918 pub fn own_counts(&self) -> GenericParamCount {
919 // We could cache this as a property of `GenericParamCount`, but
920 // the aim is to refactor this away entirely eventually and the
921 // presence of this method will be a constant reminder.
922 let mut own_counts: GenericParamCount = Default::default();
924 for param in &self.params {
926 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
927 GenericParamDefKind::Type { .. } => own_counts.types += 1,
928 GenericParamDefKind::Const => own_counts.consts += 1,
935 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
936 if self.own_requires_monomorphization() {
940 if let Some(parent_def_id) = self.parent {
941 let parent = tcx.generics_of(parent_def_id);
942 parent.requires_monomorphization(tcx)
948 pub fn own_requires_monomorphization(&self) -> bool {
949 for param in &self.params {
951 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
952 GenericParamDefKind::Lifetime => {}
960 param: &EarlyBoundRegion,
962 ) -> &'tcx GenericParamDef {
963 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
964 let param = &self.params[index as usize];
966 GenericParamDefKind::Lifetime => param,
967 _ => bug!("expected lifetime parameter, but found another generic parameter"),
970 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
971 .region_param(param, tcx)
975 /// Returns the `GenericParamDef` associated with this `ParamTy`.
976 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
977 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
978 let param = &self.params[index as usize];
980 GenericParamDefKind::Type { .. } => param,
981 _ => bug!("expected type parameter, but found another generic parameter"),
984 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
985 .type_param(param, tcx)
989 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
990 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
991 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
992 let param = &self.params[index as usize];
994 GenericParamDefKind::Const => param,
995 _ => bug!("expected const parameter, but found another generic parameter"),
998 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
999 .const_param(param, tcx)
1004 /// Bounds on generics.
1005 #[derive(Copy, Clone, Default, Debug, RustcEncodable, RustcDecodable, HashStable)]
1006 pub struct GenericPredicates<'tcx> {
1007 pub parent: Option<DefId>,
1008 pub predicates: &'tcx [(Predicate<'tcx>, Span)],
1011 impl<'tcx> GenericPredicates<'tcx> {
1015 substs: SubstsRef<'tcx>,
1016 ) -> InstantiatedPredicates<'tcx> {
1017 let mut instantiated = InstantiatedPredicates::empty();
1018 self.instantiate_into(tcx, &mut instantiated, substs);
1022 pub fn instantiate_own(
1025 substs: SubstsRef<'tcx>,
1026 ) -> InstantiatedPredicates<'tcx> {
1027 InstantiatedPredicates {
1028 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1032 fn instantiate_into(
1035 instantiated: &mut InstantiatedPredicates<'tcx>,
1036 substs: SubstsRef<'tcx>,
1038 if let Some(def_id) = self.parent {
1039 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1041 instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)));
1044 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
1045 let mut instantiated = InstantiatedPredicates::empty();
1046 self.instantiate_identity_into(tcx, &mut instantiated);
1050 fn instantiate_identity_into(
1053 instantiated: &mut InstantiatedPredicates<'tcx>,
1055 if let Some(def_id) = self.parent {
1056 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1058 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1061 pub fn instantiate_supertrait(
1064 poly_trait_ref: &ty::PolyTraitRef<'tcx>,
1065 ) -> InstantiatedPredicates<'tcx> {
1066 assert_eq!(self.parent, None);
1067 InstantiatedPredicates {
1071 .map(|(pred, _)| pred.subst_supertrait(tcx, poly_trait_ref))
1077 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1078 #[derive(HashStable, TypeFoldable)]
1079 pub enum Predicate<'tcx> {
1080 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1081 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1082 /// would be the type parameters.
1083 Trait(PolyTraitPredicate<'tcx>),
1086 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1089 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1091 /// `where <T as TraitRef>::Name == X`, approximately.
1092 /// See the `ProjectionPredicate` struct for details.
1093 Projection(PolyProjectionPredicate<'tcx>),
1095 /// No syntax: `T` well-formed.
1096 WellFormed(Ty<'tcx>),
1098 /// Trait must be object-safe.
1101 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1102 /// for some substitutions `...` and `T` being a closure type.
1103 /// Satisfied (or refuted) once we know the closure's kind.
1104 ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
1107 Subtype(PolySubtypePredicate<'tcx>),
1109 /// Constant initializer must evaluate successfully.
1110 ConstEvaluatable(DefId, SubstsRef<'tcx>),
1113 /// The crate outlives map is computed during typeck and contains the
1114 /// outlives of every item in the local crate. You should not use it
1115 /// directly, because to do so will make your pass dependent on the
1116 /// HIR of every item in the local crate. Instead, use
1117 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1119 #[derive(HashStable)]
1120 pub struct CratePredicatesMap<'tcx> {
1121 /// For each struct with outlive bounds, maps to a vector of the
1122 /// predicate of its outlive bounds. If an item has no outlives
1123 /// bounds, it will have no entry.
1124 pub predicates: FxHashMap<DefId, &'tcx [(ty::Predicate<'tcx>, Span)]>,
1127 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1128 fn as_ref(&self) -> &Predicate<'tcx> {
1133 impl<'tcx> Predicate<'tcx> {
1134 /// Performs a substitution suitable for going from a
1135 /// poly-trait-ref to supertraits that must hold if that
1136 /// poly-trait-ref holds. This is slightly different from a normal
1137 /// substitution in terms of what happens with bound regions. See
1138 /// lengthy comment below for details.
1139 pub fn subst_supertrait(
1142 trait_ref: &ty::PolyTraitRef<'tcx>,
1143 ) -> ty::Predicate<'tcx> {
1144 // The interaction between HRTB and supertraits is not entirely
1145 // obvious. Let me walk you (and myself) through an example.
1147 // Let's start with an easy case. Consider two traits:
1149 // trait Foo<'a>: Bar<'a,'a> { }
1150 // trait Bar<'b,'c> { }
1152 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1153 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1154 // knew that `Foo<'x>` (for any 'x) then we also know that
1155 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1156 // normal substitution.
1158 // In terms of why this is sound, the idea is that whenever there
1159 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1160 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1161 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1164 // Another example to be careful of is this:
1166 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1167 // trait Bar1<'b,'c> { }
1169 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1170 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1171 // reason is similar to the previous example: any impl of
1172 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1173 // basically we would want to collapse the bound lifetimes from
1174 // the input (`trait_ref`) and the supertraits.
1176 // To achieve this in practice is fairly straightforward. Let's
1177 // consider the more complicated scenario:
1179 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1180 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1181 // where both `'x` and `'b` would have a DB index of 1.
1182 // The substitution from the input trait-ref is therefore going to be
1183 // `'a => 'x` (where `'x` has a DB index of 1).
1184 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1185 // early-bound parameter and `'b' is a late-bound parameter with a
1187 // - If we replace `'a` with `'x` from the input, it too will have
1188 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1189 // just as we wanted.
1191 // There is only one catch. If we just apply the substitution `'a
1192 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1193 // adjust the DB index because we substituting into a binder (it
1194 // tries to be so smart...) resulting in `for<'x> for<'b>
1195 // Bar1<'x,'b>` (we have no syntax for this, so use your
1196 // imagination). Basically the 'x will have DB index of 2 and 'b
1197 // will have DB index of 1. Not quite what we want. So we apply
1198 // the substitution to the *contents* of the trait reference,
1199 // rather than the trait reference itself (put another way, the
1200 // substitution code expects equal binding levels in the values
1201 // from the substitution and the value being substituted into, and
1202 // this trick achieves that).
1204 let substs = &trait_ref.skip_binder().substs;
1206 Predicate::Trait(ref binder) => {
1207 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs)))
1209 Predicate::Subtype(ref binder) => {
1210 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs)))
1212 Predicate::RegionOutlives(ref binder) => {
1213 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)))
1218 Predicate::Projection(ref binder) => {
1219 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs)))
1221 Predicate::WellFormed(data) => Predicate::WellFormed(data.subst(tcx, substs)),
1222 Predicate::ObjectSafe(trait_def_id) => 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)
1226 Predicate::ConstEvaluatable(def_id, const_substs) => {
1227 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs))
1233 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1234 #[derive(HashStable, TypeFoldable)]
1235 pub struct TraitPredicate<'tcx> {
1236 pub trait_ref: TraitRef<'tcx>,
1239 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1241 impl<'tcx> TraitPredicate<'tcx> {
1242 pub fn def_id(&self) -> DefId {
1243 self.trait_ref.def_id
1246 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
1247 self.trait_ref.input_types()
1250 pub fn self_ty(&self) -> Ty<'tcx> {
1251 self.trait_ref.self_ty()
1255 impl<'tcx> PolyTraitPredicate<'tcx> {
1256 pub fn def_id(&self) -> DefId {
1257 // Ok to skip binder since trait `DefId` does not care about regions.
1258 self.skip_binder().def_id()
1262 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1263 #[derive(HashStable, TypeFoldable)]
1264 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
1265 pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
1266 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
1267 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
1268 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1269 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1271 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1272 #[derive(HashStable, TypeFoldable)]
1273 pub struct SubtypePredicate<'tcx> {
1274 pub a_is_expected: bool,
1278 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1280 /// This kind of predicate has no *direct* correspondent in the
1281 /// syntax, but it roughly corresponds to the syntactic forms:
1283 /// 1. `T: TraitRef<..., Item = Type>`
1284 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1286 /// In particular, form #1 is "desugared" to the combination of a
1287 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1288 /// predicates. Form #2 is a broader form in that it also permits
1289 /// equality between arbitrary types. Processing an instance of
1290 /// Form #2 eventually yields one of these `ProjectionPredicate`
1291 /// instances to normalize the LHS.
1292 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1293 #[derive(HashStable, TypeFoldable)]
1294 pub struct ProjectionPredicate<'tcx> {
1295 pub projection_ty: ProjectionTy<'tcx>,
1299 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1301 impl<'tcx> PolyProjectionPredicate<'tcx> {
1302 /// Returns the `DefId` of the associated item being projected.
1303 pub fn item_def_id(&self) -> DefId {
1304 self.skip_binder().projection_ty.item_def_id
1308 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
1309 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1310 // `self.0.trait_ref` is permitted to have escaping regions.
1311 // This is because here `self` has a `Binder` and so does our
1312 // return value, so we are preserving the number of binding
1314 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1317 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1318 self.map_bound(|predicate| predicate.ty)
1321 /// The `DefId` of the `TraitItem` for the associated type.
1323 /// Note that this is not the `DefId` of the `TraitRef` containing this
1324 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1325 pub fn projection_def_id(&self) -> DefId {
1326 // Ok to skip binder since trait `DefId` does not care about regions.
1327 self.skip_binder().projection_ty.item_def_id
1331 pub trait ToPolyTraitRef<'tcx> {
1332 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1335 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1336 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1337 ty::Binder::dummy(self.clone())
1341 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1342 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1343 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1347 pub trait ToPredicate<'tcx> {
1348 fn to_predicate(&self) -> Predicate<'tcx>;
1351 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1352 fn to_predicate(&self) -> Predicate<'tcx> {
1353 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate { trait_ref: self.clone() }))
1357 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1358 fn to_predicate(&self) -> Predicate<'tcx> {
1359 ty::Predicate::Trait(self.to_poly_trait_predicate())
1363 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1364 fn to_predicate(&self) -> Predicate<'tcx> {
1365 Predicate::RegionOutlives(self.clone())
1369 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1370 fn to_predicate(&self) -> Predicate<'tcx> {
1371 Predicate::TypeOutlives(self.clone())
1375 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1376 fn to_predicate(&self) -> Predicate<'tcx> {
1377 Predicate::Projection(self.clone())
1381 // A custom iterator used by `Predicate::walk_tys`.
1382 enum WalkTysIter<'tcx, I, J, K>
1384 I: Iterator<Item = Ty<'tcx>>,
1385 J: Iterator<Item = Ty<'tcx>>,
1386 K: Iterator<Item = Ty<'tcx>>,
1390 Two(Ty<'tcx>, Ty<'tcx>),
1396 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1398 I: Iterator<Item = Ty<'tcx>>,
1399 J: Iterator<Item = Ty<'tcx>>,
1400 K: Iterator<Item = Ty<'tcx>>,
1402 type Item = Ty<'tcx>;
1404 fn next(&mut self) -> Option<Ty<'tcx>> {
1406 WalkTysIter::None => None,
1407 WalkTysIter::One(item) => {
1408 *self = WalkTysIter::None;
1411 WalkTysIter::Two(item1, item2) => {
1412 *self = WalkTysIter::One(item2);
1415 WalkTysIter::Types(ref mut iter) => iter.next(),
1416 WalkTysIter::InputTypes(ref mut iter) => iter.next(),
1417 WalkTysIter::ProjectionTypes(ref mut iter) => iter.next(),
1422 impl<'tcx> Predicate<'tcx> {
1423 /// Iterates over the types in this predicate. Note that in all
1424 /// cases this is skipping over a binder, so late-bound regions
1425 /// with depth 0 are bound by the predicate.
1426 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1428 ty::Predicate::Trait(ref data) => {
1429 WalkTysIter::InputTypes(data.skip_binder().input_types())
1431 ty::Predicate::Subtype(binder) => {
1432 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1433 WalkTysIter::Two(a, b)
1435 ty::Predicate::TypeOutlives(binder) => WalkTysIter::One(binder.skip_binder().0),
1436 ty::Predicate::RegionOutlives(..) => WalkTysIter::None,
1437 ty::Predicate::Projection(ref data) => {
1438 let inner = data.skip_binder();
1439 WalkTysIter::ProjectionTypes(
1440 inner.projection_ty.substs.types().chain(Some(inner.ty)),
1443 ty::Predicate::WellFormed(data) => WalkTysIter::One(data),
1444 ty::Predicate::ObjectSafe(_trait_def_id) => WalkTysIter::None,
1445 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1446 WalkTysIter::Types(closure_substs.types())
1448 ty::Predicate::ConstEvaluatable(_, substs) => WalkTysIter::Types(substs.types()),
1452 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1454 Predicate::Trait(ref t) => Some(t.to_poly_trait_ref()),
1455 Predicate::Projection(..)
1456 | Predicate::Subtype(..)
1457 | Predicate::RegionOutlives(..)
1458 | Predicate::WellFormed(..)
1459 | Predicate::ObjectSafe(..)
1460 | Predicate::ClosureKind(..)
1461 | Predicate::TypeOutlives(..)
1462 | Predicate::ConstEvaluatable(..) => None,
1466 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1468 Predicate::TypeOutlives(data) => Some(data),
1469 Predicate::Trait(..)
1470 | Predicate::Projection(..)
1471 | Predicate::Subtype(..)
1472 | Predicate::RegionOutlives(..)
1473 | Predicate::WellFormed(..)
1474 | Predicate::ObjectSafe(..)
1475 | Predicate::ClosureKind(..)
1476 | Predicate::ConstEvaluatable(..) => None,
1481 /// Represents the bounds declared on a particular set of type
1482 /// parameters. Should eventually be generalized into a flag list of
1483 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1484 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1485 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1486 /// the `GenericPredicates` are expressed in terms of the bound type
1487 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1488 /// represented a set of bounds for some particular instantiation,
1489 /// meaning that the generic parameters have been substituted with
1494 /// struct Foo<T, U: Bar<T>> { ... }
1496 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1497 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1498 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1499 /// [usize:Bar<isize>]]`.
1500 #[derive(Clone, Debug, TypeFoldable)]
1501 pub struct InstantiatedPredicates<'tcx> {
1502 pub predicates: Vec<Predicate<'tcx>>,
1505 impl<'tcx> InstantiatedPredicates<'tcx> {
1506 pub fn empty() -> InstantiatedPredicates<'tcx> {
1507 InstantiatedPredicates { predicates: vec![] }
1510 pub fn is_empty(&self) -> bool {
1511 self.predicates.is_empty()
1515 rustc_index::newtype_index! {
1516 /// "Universes" are used during type- and trait-checking in the
1517 /// presence of `for<..>` binders to control what sets of names are
1518 /// visible. Universes are arranged into a tree: the root universe
1519 /// contains names that are always visible. Each child then adds a new
1520 /// set of names that are visible, in addition to those of its parent.
1521 /// We say that the child universe "extends" the parent universe with
1524 /// To make this more concrete, consider this program:
1528 /// fn bar<T>(x: T) {
1529 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1533 /// The struct name `Foo` is in the root universe U0. But the type
1534 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1535 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1536 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1537 /// region `'a` is in a universe U2 that extends U1, because we can
1538 /// name it inside the fn type but not outside.
1540 /// Universes are used to do type- and trait-checking around these
1541 /// "forall" binders (also called **universal quantification**). The
1542 /// idea is that when, in the body of `bar`, we refer to `T` as a
1543 /// type, we aren't referring to any type in particular, but rather a
1544 /// kind of "fresh" type that is distinct from all other types we have
1545 /// actually declared. This is called a **placeholder** type, and we
1546 /// use universes to talk about this. In other words, a type name in
1547 /// universe 0 always corresponds to some "ground" type that the user
1548 /// declared, but a type name in a non-zero universe is a placeholder
1549 /// type -- an idealized representative of "types in general" that we
1550 /// use for checking generic functions.
1551 pub struct UniverseIndex {
1553 DEBUG_FORMAT = "U{}",
1557 impl UniverseIndex {
1558 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1560 /// Returns the "next" universe index in order -- this new index
1561 /// is considered to extend all previous universes. This
1562 /// corresponds to entering a `forall` quantifier. So, for
1563 /// example, suppose we have this type in universe `U`:
1566 /// for<'a> fn(&'a u32)
1569 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1570 /// new universe that extends `U` -- in this new universe, we can
1571 /// name the region `'a`, but that region was not nameable from
1572 /// `U` because it was not in scope there.
1573 pub fn next_universe(self) -> UniverseIndex {
1574 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1577 /// Returns `true` if `self` can name a name from `other` -- in other words,
1578 /// if the set of names in `self` is a superset of those in
1579 /// `other` (`self >= other`).
1580 pub fn can_name(self, other: UniverseIndex) -> bool {
1581 self.private >= other.private
1584 /// Returns `true` if `self` cannot name some names from `other` -- in other
1585 /// words, if the set of names in `self` is a strict subset of
1586 /// those in `other` (`self < other`).
1587 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1588 self.private < other.private
1592 /// The "placeholder index" fully defines a placeholder region.
1593 /// Placeholder regions are identified by both a **universe** as well
1594 /// as a "bound-region" within that universe. The `bound_region` is
1595 /// basically a name -- distinct bound regions within the same
1596 /// universe are just two regions with an unknown relationship to one
1598 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1599 pub struct Placeholder<T> {
1600 pub universe: UniverseIndex,
1604 impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1606 T: HashStable<StableHashingContext<'a>>,
1608 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1609 self.universe.hash_stable(hcx, hasher);
1610 self.name.hash_stable(hcx, hasher);
1614 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1616 pub type PlaceholderType = Placeholder<BoundVar>;
1618 pub type PlaceholderConst = Placeholder<BoundVar>;
1620 /// When type checking, we use the `ParamEnv` to track
1621 /// details about the set of where-clauses that are in scope at this
1622 /// particular point.
1623 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TypeFoldable)]
1624 pub struct ParamEnv<'tcx> {
1625 /// `Obligation`s that the caller must satisfy. This is basically
1626 /// the set of bounds on the in-scope type parameters, translated
1627 /// into `Obligation`s, and elaborated and normalized.
1628 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1630 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1631 /// want `Reveal::All` -- note that this is always paired with an
1632 /// empty environment. To get that, use `ParamEnv::reveal()`.
1633 pub reveal: traits::Reveal,
1635 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1636 /// register that `def_id` (useful for transitioning to the chalk trait
1638 pub def_id: Option<DefId>,
1641 impl<'tcx> ParamEnv<'tcx> {
1642 /// Construct a trait environment suitable for contexts where
1643 /// there are no where-clauses in scope. Hidden types (like `impl
1644 /// Trait`) are left hidden, so this is suitable for ordinary
1647 pub fn empty() -> Self {
1648 Self::new(List::empty(), Reveal::UserFacing, None)
1651 /// Construct a trait environment with no where-clauses in scope
1652 /// where the values of all `impl Trait` and other hidden types
1653 /// are revealed. This is suitable for monomorphized, post-typeck
1654 /// environments like codegen or doing optimizations.
1656 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1657 /// or invoke `param_env.with_reveal_all()`.
1659 pub fn reveal_all() -> Self {
1660 Self::new(List::empty(), Reveal::All, None)
1663 /// Construct a trait environment with the given set of predicates.
1666 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1668 def_id: Option<DefId>,
1670 ty::ParamEnv { caller_bounds, reveal, def_id }
1673 /// Returns a new parameter environment with the same clauses, but
1674 /// which "reveals" the true results of projections in all cases
1675 /// (even for associated types that are specializable). This is
1676 /// the desired behavior during codegen and certain other special
1677 /// contexts; normally though we want to use `Reveal::UserFacing`,
1678 /// which is the default.
1679 pub fn with_reveal_all(self) -> Self {
1680 ty::ParamEnv { reveal: Reveal::All, ..self }
1683 /// Returns this same environment but with no caller bounds.
1684 pub fn without_caller_bounds(self) -> Self {
1685 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1688 /// Creates a suitable environment in which to perform trait
1689 /// queries on the given value. When type-checking, this is simply
1690 /// the pair of the environment plus value. But when reveal is set to
1691 /// All, then if `value` does not reference any type parameters, we will
1692 /// pair it with the empty environment. This improves caching and is generally
1695 /// N.B., we preserve the environment when type-checking because it
1696 /// is possible for the user to have wacky where-clauses like
1697 /// `where Box<u32>: Copy`, which are clearly never
1698 /// satisfiable. We generally want to behave as if they were true,
1699 /// although the surrounding function is never reachable.
1700 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1702 Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
1705 if value.has_placeholders() || value.needs_infer() || value.has_param_types() {
1706 ParamEnvAnd { param_env: self, value }
1708 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1715 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1716 pub struct ParamEnvAnd<'tcx, T> {
1717 pub param_env: ParamEnv<'tcx>,
1721 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1722 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1723 (self.param_env, self.value)
1727 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
1729 T: HashStable<StableHashingContext<'a>>,
1731 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1732 let ParamEnvAnd { ref param_env, ref value } = *self;
1734 param_env.hash_stable(hcx, hasher);
1735 value.hash_stable(hcx, hasher);
1739 #[derive(Copy, Clone, Debug, HashStable)]
1740 pub struct Destructor {
1741 /// The `DefId` of the destructor method
1746 #[derive(HashStable)]
1747 pub struct AdtFlags: u32 {
1748 const NO_ADT_FLAGS = 0;
1749 /// Indicates whether the ADT is an enum.
1750 const IS_ENUM = 1 << 0;
1751 /// Indicates whether the ADT is a union.
1752 const IS_UNION = 1 << 1;
1753 /// Indicates whether the ADT is a struct.
1754 const IS_STRUCT = 1 << 2;
1755 /// Indicates whether the ADT is a struct and has a constructor.
1756 const HAS_CTOR = 1 << 3;
1757 /// Indicates whether the type is a `PhantomData`.
1758 const IS_PHANTOM_DATA = 1 << 4;
1759 /// Indicates whether the type has a `#[fundamental]` attribute.
1760 const IS_FUNDAMENTAL = 1 << 5;
1761 /// Indicates whether the type is a `Box`.
1762 const IS_BOX = 1 << 6;
1763 /// Indicates whether the type is an `Arc`.
1764 const IS_ARC = 1 << 7;
1765 /// Indicates whether the type is an `Rc`.
1766 const IS_RC = 1 << 8;
1767 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1768 /// (i.e., this flag is never set unless this ADT is an enum).
1769 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1774 #[derive(HashStable)]
1775 pub struct VariantFlags: u32 {
1776 const NO_VARIANT_FLAGS = 0;
1777 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1778 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1782 /// Definition of a variant -- a struct's fields or a enum variant.
1783 #[derive(Debug, HashStable)]
1784 pub struct VariantDef {
1785 /// `DefId` that identifies the variant itself.
1786 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1788 /// `DefId` that identifies the variant's constructor.
1789 /// If this variant is a struct variant, then this is `None`.
1790 pub ctor_def_id: Option<DefId>,
1791 /// Variant or struct name.
1792 #[stable_hasher(project(name))]
1794 /// Discriminant of this variant.
1795 pub discr: VariantDiscr,
1796 /// Fields of this variant.
1797 pub fields: Vec<FieldDef>,
1798 /// Type of constructor of variant.
1799 pub ctor_kind: CtorKind,
1800 /// Flags of the variant (e.g. is field list non-exhaustive)?
1801 flags: VariantFlags,
1802 /// Variant is obtained as part of recovering from a syntactic error.
1803 /// May be incomplete or bogus.
1804 pub recovered: bool,
1807 impl<'tcx> VariantDef {
1808 /// Creates a new `VariantDef`.
1810 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1811 /// represents an enum variant).
1813 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1814 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1816 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1817 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1818 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1819 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1820 /// built-in trait), and we do not want to load attributes twice.
1822 /// If someone speeds up attribute loading to not be a performance concern, they can
1823 /// remove this hack and use the constructor `DefId` everywhere.
1827 variant_did: Option<DefId>,
1828 ctor_def_id: Option<DefId>,
1829 discr: VariantDiscr,
1830 fields: Vec<FieldDef>,
1831 ctor_kind: CtorKind,
1837 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1838 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1839 ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
1842 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1843 if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
1844 debug!("found non-exhaustive field list for {:?}", parent_did);
1845 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1846 } else if let Some(variant_did) = variant_did {
1847 if tcx.has_attr(variant_did, sym::non_exhaustive) {
1848 debug!("found non-exhaustive field list for {:?}", variant_did);
1849 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1854 def_id: variant_did.unwrap_or(parent_did),
1865 /// Is this field list non-exhaustive?
1867 pub fn is_field_list_non_exhaustive(&self) -> bool {
1868 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1872 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1873 pub enum VariantDiscr {
1874 /// Explicit value for this variant, i.e., `X = 123`.
1875 /// The `DefId` corresponds to the embedded constant.
1878 /// The previous variant's discriminant plus one.
1879 /// For efficiency reasons, the distance from the
1880 /// last `Explicit` discriminant is being stored,
1881 /// or `0` for the first variant, if it has none.
1885 #[derive(Debug, HashStable)]
1886 pub struct FieldDef {
1888 #[stable_hasher(project(name))]
1890 pub vis: Visibility,
1893 /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
1895 /// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
1897 /// The initialism *ADT* stands for an [*algebraic data type (ADT)*][adt].
1898 /// This is slightly wrong because `union`s are not ADTs.
1899 /// Moreover, Rust only allows recursive data types through indirection.
1901 /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
1903 /// The `DefId` of the struct, enum or union item.
1905 /// Variants of the ADT. If this is a struct or union, then there will be a single variant.
1906 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1907 /// Flags of the ADT (e.g., is this a struct? is this non-exhaustive?).
1909 /// Repr options provided by the user.
1910 pub repr: ReprOptions,
1913 impl PartialOrd for AdtDef {
1914 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1915 Some(self.cmp(&other))
1919 /// There should be only one AdtDef for each `did`, therefore
1920 /// it is fine to implement `Ord` only based on `did`.
1921 impl Ord for AdtDef {
1922 fn cmp(&self, other: &AdtDef) -> Ordering {
1923 self.did.cmp(&other.did)
1927 impl PartialEq for AdtDef {
1928 // `AdtDef`s are always interned, and this is part of `TyS` equality.
1930 fn eq(&self, other: &Self) -> bool {
1931 ptr::eq(self, other)
1935 impl Eq for AdtDef {}
1937 impl Hash for AdtDef {
1939 fn hash<H: Hasher>(&self, s: &mut H) {
1940 (self as *const AdtDef).hash(s)
1944 impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef {
1945 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1950 impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1952 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1953 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
1955 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1958 let hash: Fingerprint = CACHE.with(|cache| {
1959 let addr = self as *const AdtDef as usize;
1960 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1961 let ty::AdtDef { did, ref variants, ref flags, ref repr } = *self;
1963 let mut hasher = StableHasher::new();
1964 did.hash_stable(hcx, &mut hasher);
1965 variants.hash_stable(hcx, &mut hasher);
1966 flags.hash_stable(hcx, &mut hasher);
1967 repr.hash_stable(hcx, &mut hasher);
1973 hash.hash_stable(hcx, hasher);
1977 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1984 impl Into<DataTypeKind> for AdtKind {
1985 fn into(self) -> DataTypeKind {
1987 AdtKind::Struct => DataTypeKind::Struct,
1988 AdtKind::Union => DataTypeKind::Union,
1989 AdtKind::Enum => DataTypeKind::Enum,
1995 #[derive(RustcEncodable, RustcDecodable, Default, HashStable)]
1996 pub struct ReprFlags: u8 {
1997 const IS_C = 1 << 0;
1998 const IS_SIMD = 1 << 1;
1999 const IS_TRANSPARENT = 1 << 2;
2000 // Internal only for now. If true, don't reorder fields.
2001 const IS_LINEAR = 1 << 3;
2003 // Any of these flags being set prevent field reordering optimisation.
2004 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
2005 ReprFlags::IS_SIMD.bits |
2006 ReprFlags::IS_LINEAR.bits;
2010 /// Represents the repr options provided by the user,
2011 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default, HashStable)]
2012 pub struct ReprOptions {
2013 pub int: Option<attr::IntType>,
2014 pub align: Option<Align>,
2015 pub pack: Option<Align>,
2016 pub flags: ReprFlags,
2020 pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
2021 let mut flags = ReprFlags::empty();
2022 let mut size = None;
2023 let mut max_align: Option<Align> = None;
2024 let mut min_pack: Option<Align> = None;
2025 for attr in tcx.get_attrs(did).iter() {
2026 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2027 flags.insert(match r {
2028 attr::ReprC => ReprFlags::IS_C,
2029 attr::ReprPacked(pack) => {
2030 let pack = Align::from_bytes(pack as u64).unwrap();
2031 min_pack = Some(if let Some(min_pack) = min_pack {
2038 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2039 attr::ReprSimd => ReprFlags::IS_SIMD,
2040 attr::ReprInt(i) => {
2044 attr::ReprAlign(align) => {
2045 max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
2052 // This is here instead of layout because the choice must make it into metadata.
2053 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
2054 flags.insert(ReprFlags::IS_LINEAR);
2056 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2060 pub fn simd(&self) -> bool {
2061 self.flags.contains(ReprFlags::IS_SIMD)
2064 pub fn c(&self) -> bool {
2065 self.flags.contains(ReprFlags::IS_C)
2068 pub fn packed(&self) -> bool {
2072 pub fn transparent(&self) -> bool {
2073 self.flags.contains(ReprFlags::IS_TRANSPARENT)
2076 pub fn linear(&self) -> bool {
2077 self.flags.contains(ReprFlags::IS_LINEAR)
2080 pub fn discr_type(&self) -> attr::IntType {
2081 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2084 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2085 /// layout" optimizations, such as representing `Foo<&T>` as a
2087 pub fn inhibit_enum_layout_opt(&self) -> bool {
2088 self.c() || self.int.is_some()
2091 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2092 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2093 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2094 if let Some(pack) = self.pack {
2095 if pack.bytes() == 1 {
2099 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
2102 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2103 pub fn inhibit_union_abi_opt(&self) -> bool {
2109 /// Creates a new `AdtDef`.
2114 variants: IndexVec<VariantIdx, VariantDef>,
2117 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2118 let mut flags = AdtFlags::NO_ADT_FLAGS;
2120 if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
2121 debug!("found non-exhaustive variant list for {:?}", did);
2122 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2125 flags |= match kind {
2126 AdtKind::Enum => AdtFlags::IS_ENUM,
2127 AdtKind::Union => AdtFlags::IS_UNION,
2128 AdtKind::Struct => AdtFlags::IS_STRUCT,
2131 if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
2132 flags |= AdtFlags::HAS_CTOR;
2135 let attrs = tcx.get_attrs(did);
2136 if attr::contains_name(&attrs, sym::fundamental) {
2137 flags |= AdtFlags::IS_FUNDAMENTAL;
2139 if Some(did) == tcx.lang_items().phantom_data() {
2140 flags |= AdtFlags::IS_PHANTOM_DATA;
2142 if Some(did) == tcx.lang_items().owned_box() {
2143 flags |= AdtFlags::IS_BOX;
2145 if Some(did) == tcx.lang_items().arc() {
2146 flags |= AdtFlags::IS_ARC;
2148 if Some(did) == tcx.lang_items().rc() {
2149 flags |= AdtFlags::IS_RC;
2152 AdtDef { did, variants, flags, repr }
2155 /// Returns `true` if this is a struct.
2157 pub fn is_struct(&self) -> bool {
2158 self.flags.contains(AdtFlags::IS_STRUCT)
2161 /// Returns `true` if this is a union.
2163 pub fn is_union(&self) -> bool {
2164 self.flags.contains(AdtFlags::IS_UNION)
2167 /// Returns `true` if this is a enum.
2169 pub fn is_enum(&self) -> bool {
2170 self.flags.contains(AdtFlags::IS_ENUM)
2173 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2175 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2176 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2179 /// Returns the kind of the ADT.
2181 pub fn adt_kind(&self) -> AdtKind {
2184 } else if self.is_union() {
2191 /// Returns a description of this abstract data type.
2192 pub fn descr(&self) -> &'static str {
2193 match self.adt_kind() {
2194 AdtKind::Struct => "struct",
2195 AdtKind::Union => "union",
2196 AdtKind::Enum => "enum",
2200 /// Returns a description of a variant of this abstract data type.
2202 pub fn variant_descr(&self) -> &'static str {
2203 match self.adt_kind() {
2204 AdtKind::Struct => "struct",
2205 AdtKind::Union => "union",
2206 AdtKind::Enum => "variant",
2210 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2212 pub fn has_ctor(&self) -> bool {
2213 self.flags.contains(AdtFlags::HAS_CTOR)
2216 /// Returns `true` if this type is `#[fundamental]` for the purposes
2217 /// of coherence checking.
2219 pub fn is_fundamental(&self) -> bool {
2220 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2223 /// Returns `true` if this is `PhantomData<T>`.
2225 pub fn is_phantom_data(&self) -> bool {
2226 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2229 /// Returns `true` if this is `Arc<T>`.
2230 pub fn is_arc(&self) -> bool {
2231 self.flags.contains(AdtFlags::IS_ARC)
2234 /// Returns `true` if this is `Rc<T>`.
2235 pub fn is_rc(&self) -> bool {
2236 self.flags.contains(AdtFlags::IS_RC)
2239 /// Returns `true` if this is Box<T>.
2241 pub fn is_box(&self) -> bool {
2242 self.flags.contains(AdtFlags::IS_BOX)
2245 /// Returns `true` if this type has a destructor.
2246 pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
2247 self.destructor(tcx).is_some()
2250 /// Asserts this is a struct or union and returns its unique variant.
2251 pub fn non_enum_variant(&self) -> &VariantDef {
2252 assert!(self.is_struct() || self.is_union());
2253 &self.variants[VariantIdx::new(0)]
2257 pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> {
2258 tcx.predicates_of(self.did)
2261 /// Returns an iterator over all fields contained
2264 pub fn all_fields(&self) -> impl Iterator<Item = &FieldDef> + Clone {
2265 self.variants.iter().flat_map(|v| v.fields.iter())
2268 pub fn is_payloadfree(&self) -> bool {
2269 !self.variants.is_empty() && self.variants.iter().all(|v| v.fields.is_empty())
2272 /// Return a `VariantDef` given a variant id.
2273 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2274 self.variants.iter().find(|v| v.def_id == vid).expect("variant_with_id: unknown variant")
2277 /// Return a `VariantDef` given a constructor id.
2278 pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
2281 .find(|v| v.ctor_def_id == Some(cid))
2282 .expect("variant_with_ctor_id: unknown variant")
2285 /// Return the index of `VariantDef` given a variant id.
2286 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2289 .find(|(_, v)| v.def_id == vid)
2290 .expect("variant_index_with_id: unknown variant")
2294 /// Return the index of `VariantDef` given a constructor id.
2295 pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
2298 .find(|(_, v)| v.ctor_def_id == Some(cid))
2299 .expect("variant_index_with_ctor_id: unknown variant")
2303 pub fn variant_of_res(&self, res: Res) -> &VariantDef {
2305 Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
2306 Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
2307 Res::Def(DefKind::Struct, _)
2308 | Res::Def(DefKind::Union, _)
2309 | Res::Def(DefKind::TyAlias, _)
2310 | Res::Def(DefKind::AssocTy, _)
2312 | Res::SelfCtor(..) => self.non_enum_variant(),
2313 _ => bug!("unexpected res {:?} in variant_of_res", res),
2318 pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
2319 let param_env = tcx.param_env(expr_did);
2320 let repr_type = self.repr.discr_type();
2321 match tcx.const_eval_poly(expr_did) {
2323 // FIXME: Find the right type and use it instead of `val.ty` here
2324 if let Some(b) = val.try_eval_bits(tcx, param_env, val.ty) {
2325 trace!("discriminants: {} ({:?})", b, repr_type);
2326 Some(Discr { val: b, ty: val.ty })
2328 info!("invalid enum discriminant: {:#?}", val);
2329 crate::mir::interpret::struct_error(
2330 tcx.at(tcx.def_span(expr_did)),
2331 "constant evaluation of enum discriminant resulted in non-integer",
2337 Err(ErrorHandled::Reported) => {
2338 if !expr_did.is_local() {
2340 tcx.def_span(expr_did),
2341 "variant discriminant evaluation succeeded \
2342 in its crate but failed locally"
2347 Err(ErrorHandled::TooGeneric) => {
2348 span_bug!(tcx.def_span(expr_did), "enum discriminant depends on generic arguments",)
2354 pub fn discriminants(
2357 ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
2358 let repr_type = self.repr.discr_type();
2359 let initial = repr_type.initial_discriminant(tcx);
2360 let mut prev_discr = None::<Discr<'tcx>>;
2361 self.variants.iter_enumerated().map(move |(i, v)| {
2362 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2363 if let VariantDiscr::Explicit(expr_did) = v.discr {
2364 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2368 prev_discr = Some(discr);
2375 pub fn variant_range(&self) -> Range<VariantIdx> {
2376 (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
2379 /// Computes the discriminant value used by a specific variant.
2380 /// Unlike `discriminants`, this is (amortized) constant-time,
2381 /// only doing at most one query for evaluating an explicit
2382 /// discriminant (the last one before the requested variant),
2383 /// assuming there are no constant-evaluation errors there.
2385 pub fn discriminant_for_variant(
2388 variant_index: VariantIdx,
2390 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2391 let explicit_value = val
2392 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2393 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
2394 explicit_value.checked_add(tcx, offset as u128).0
2397 /// Yields a `DefId` for the discriminant and an offset to add to it
2398 /// Alternatively, if there is no explicit discriminant, returns the
2399 /// inferred discriminant directly.
2400 pub fn discriminant_def_for_variant(&self, variant_index: VariantIdx) -> (Option<DefId>, u32) {
2401 let mut explicit_index = variant_index.as_u32();
2404 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2405 ty::VariantDiscr::Relative(0) => {
2409 ty::VariantDiscr::Relative(distance) => {
2410 explicit_index -= distance;
2412 ty::VariantDiscr::Explicit(did) => {
2413 expr_did = Some(did);
2418 (expr_did, variant_index.as_u32() - explicit_index)
2421 pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
2422 tcx.adt_destructor(self.did)
2425 /// Returns a list of types such that `Self: Sized` if and only
2426 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2428 /// Oddly enough, checking that the sized-constraint is `Sized` is
2429 /// actually more expressive than checking all members:
2430 /// the `Sized` trait is inductive, so an associated type that references
2431 /// `Self` would prevent its containing ADT from being `Sized`.
2433 /// Due to normalization being eager, this applies even if
2434 /// the associated type is behind a pointer (e.g., issue #31299).
2435 pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
2436 tcx.adt_sized_constraint(self.did).0
2439 fn sized_constraint_for_ty(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Vec<Ty<'tcx>> {
2440 let result = match ty.kind {
2441 Bool | Char | Int(..) | Uint(..) | Float(..) | RawPtr(..) | Ref(..) | FnDef(..)
2442 | FnPtr(_) | Array(..) | Closure(..) | Generator(..) | Never => vec![],
2444 Str | Dynamic(..) | Slice(_) | Foreign(..) | Error | GeneratorWitness(..) => {
2445 // these are never sized - return the target type
2449 Tuple(ref tys) => match tys.last() {
2451 Some(ty) => self.sized_constraint_for_ty(tcx, ty.expect_ty()),
2454 Adt(adt, substs) => {
2456 let adt_tys = adt.sized_constraint(tcx);
2457 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}", ty, adt_tys);
2460 .map(|ty| ty.subst(tcx, substs))
2461 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2465 Projection(..) | Opaque(..) => {
2466 // must calculate explicitly.
2467 // FIXME: consider special-casing always-Sized projections
2471 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2474 // perf hack: if there is a `T: Sized` bound, then
2475 // we know that `T` is Sized and do not need to check
2478 let sized_trait = match tcx.lang_items().sized_trait() {
2480 _ => return vec![ty],
2482 let sized_predicate = Binder::dummy(TraitRef {
2483 def_id: sized_trait,
2484 substs: tcx.mk_substs_trait(ty, &[]),
2487 let predicates = tcx.predicates_of(self.did).predicates;
2488 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2495 Placeholder(..) | Bound(..) | Infer(..) => {
2496 bug!("unexpected type `{:?}` in sized_constraint_for_ty", ty)
2499 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2504 impl<'tcx> FieldDef {
2505 /// Returns the type of this field. The `subst` is typically obtained
2506 /// via the second field of `TyKind::AdtDef`.
2507 pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
2508 tcx.type_of(self.did).subst(tcx, subst)
2512 /// Represents the various closure traits in the language. This
2513 /// will determine the type of the environment (`self`, in the
2514 /// desugaring) argument that the closure expects.
2516 /// You can get the environment type of a closure using
2517 /// `tcx.closure_env_ty()`.
2531 pub enum ClosureKind {
2532 // Warning: Ordering is significant here! The ordering is chosen
2533 // because the trait Fn is a subtrait of FnMut and so in turn, and
2534 // hence we order it so that Fn < FnMut < FnOnce.
2540 impl<'tcx> ClosureKind {
2541 // This is the initial value used when doing upvar inference.
2542 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2544 pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
2546 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem, None),
2547 ClosureKind::FnMut => tcx.require_lang_item(FnMutTraitLangItem, None),
2548 ClosureKind::FnOnce => tcx.require_lang_item(FnOnceTraitLangItem, None),
2552 /// Returns `true` if this a type that impls this closure kind
2553 /// must also implement `other`.
2554 pub fn extends(self, other: ty::ClosureKind) -> bool {
2555 match (self, other) {
2556 (ClosureKind::Fn, ClosureKind::Fn) => true,
2557 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2558 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2559 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2560 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2561 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2566 /// Returns the representative scalar type for this closure kind.
2567 /// See `TyS::to_opt_closure_kind` for more details.
2568 pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
2570 ty::ClosureKind::Fn => tcx.types.i8,
2571 ty::ClosureKind::FnMut => tcx.types.i16,
2572 ty::ClosureKind::FnOnce => tcx.types.i32,
2577 impl<'tcx> TyS<'tcx> {
2578 /// Iterator that walks `self` and any types reachable from
2579 /// `self`, in depth-first order. Note that just walks the types
2580 /// that appear in `self`, it does not descend into the fields of
2581 /// structs or variants. For example:
2584 /// isize => { isize }
2585 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2586 /// [isize] => { [isize], isize }
2588 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2589 TypeWalker::new(self)
2592 /// Iterator that walks the immediate children of `self`. Hence
2593 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2594 /// (but not `i32`, like `walk`).
2595 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2596 walk::walk_shallow(self)
2599 /// Walks `ty` and any types appearing within `ty`, invoking the
2600 /// callback `f` on each type. If the callback returns `false`, then the
2601 /// children of the current type are ignored.
2603 /// Note: prefer `ty.walk()` where possible.
2604 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2606 F: FnMut(Ty<'tcx>) -> bool,
2608 let mut walker = self.walk();
2609 while let Some(ty) = walker.next() {
2611 walker.skip_current_subtree();
2618 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2620 hir::Mutability::Mut => MutBorrow,
2621 hir::Mutability::Not => ImmBorrow,
2625 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2626 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2627 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2629 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2631 MutBorrow => hir::Mutability::Mut,
2632 ImmBorrow => hir::Mutability::Not,
2634 // We have no type corresponding to a unique imm borrow, so
2635 // use `&mut`. It gives all the capabilities of an `&uniq`
2636 // and hence is a safe "over approximation".
2637 UniqueImmBorrow => hir::Mutability::Mut,
2641 pub fn to_user_str(&self) -> &'static str {
2643 MutBorrow => "mutable",
2644 ImmBorrow => "immutable",
2645 UniqueImmBorrow => "uniquely immutable",
2650 #[derive(Debug, Clone)]
2651 pub enum Attributes<'tcx> {
2652 Owned(Lrc<[ast::Attribute]>),
2653 Borrowed(&'tcx [ast::Attribute]),
2656 impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
2657 type Target = [ast::Attribute];
2659 fn deref(&self) -> &[ast::Attribute] {
2661 &Attributes::Owned(ref data) => &data,
2662 &Attributes::Borrowed(data) => data,
2667 #[derive(Debug, PartialEq, Eq)]
2668 pub enum ImplOverlapKind {
2669 /// These impls are always allowed to overlap.
2671 /// These impls are allowed to overlap, but that raises
2672 /// an issue #33140 future-compatibility warning.
2674 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2675 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2677 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2678 /// that difference, making what reduces to the following set of impls:
2682 /// impl Trait for dyn Send + Sync {}
2683 /// impl Trait for dyn Sync + Send {}
2686 /// Obviously, once we made these types be identical, that code causes a coherence
2687 /// error and a fairly big headache for us. However, luckily for us, the trait
2688 /// `Trait` used in this case is basically a marker trait, and therefore having
2689 /// overlapping impls for it is sound.
2691 /// To handle this, we basically regard the trait as a marker trait, with an additional
2692 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2693 /// it has the following restrictions:
2695 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2697 /// 2. The trait-ref of both impls must be equal.
2698 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2700 /// 4. Neither of the impls can have any where-clauses.
2702 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2706 impl<'tcx> TyCtxt<'tcx> {
2707 pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
2708 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2711 /// Returns an iterator of the `DefId`s for all body-owners in this
2712 /// crate. If you would prefer to iterate over the bodies
2713 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2714 pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
2719 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2722 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2723 par_iter(&self.hir().krate().body_ids)
2724 .for_each(|&body_id| f(self.hir().body_owner_def_id(body_id)));
2727 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssocItem> {
2728 self.associated_items(id)
2729 .filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
2733 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2734 self.associated_items(did).any(|item| item.relevant_for_never())
2737 pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
2738 self.hir().as_local_hir_id(def_id).and_then(|hir_id| self.hir().get(hir_id).ident())
2741 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
2742 let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
2743 match self.hir().get(hir_id) {
2744 Node::TraitItem(_) | Node::ImplItem(_) => true,
2748 match self.def_kind(def_id).expect("no def for `DefId`") {
2749 DefKind::AssocConst | DefKind::Method | DefKind::AssocTy => true,
2754 is_associated_item.then(|| self.associated_item(def_id))
2757 fn associated_item_from_trait_item_ref(
2759 parent_def_id: DefId,
2760 parent_vis: &hir::Visibility<'_>,
2761 trait_item_ref: &hir::TraitItemRef,
2763 let def_id = self.hir().local_def_id(trait_item_ref.id.hir_id);
2764 let (kind, has_self) = match trait_item_ref.kind {
2765 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2766 hir::AssocItemKind::Method { has_self } => (ty::AssocKind::Method, has_self),
2767 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2768 hir::AssocItemKind::OpaqueTy => bug!("only impls can have opaque types"),
2772 ident: trait_item_ref.ident,
2774 // Visibility of trait items is inherited from their traits.
2775 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.hir_id, self),
2776 defaultness: trait_item_ref.defaultness,
2778 container: TraitContainer(parent_def_id),
2779 method_has_self_argument: has_self,
2783 fn associated_item_from_impl_item_ref(
2785 parent_def_id: DefId,
2786 impl_item_ref: &hir::ImplItemRef<'_>,
2788 let def_id = self.hir().local_def_id(impl_item_ref.id.hir_id);
2789 let (kind, has_self) = match impl_item_ref.kind {
2790 hir::AssocItemKind::Const => (ty::AssocKind::Const, false),
2791 hir::AssocItemKind::Method { has_self } => (ty::AssocKind::Method, has_self),
2792 hir::AssocItemKind::Type => (ty::AssocKind::Type, false),
2793 hir::AssocItemKind::OpaqueTy => (ty::AssocKind::OpaqueTy, false),
2797 ident: impl_item_ref.ident,
2799 // Visibility of trait impl items doesn't matter.
2800 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.hir_id, self),
2801 defaultness: impl_item_ref.defaultness,
2803 container: ImplContainer(parent_def_id),
2804 method_has_self_argument: has_self,
2808 pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
2809 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2812 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2813 variant.fields.iter().position(|field| self.hygienic_eq(ident, field.ident, variant.def_id))
2816 pub fn associated_items(self, def_id: DefId) -> AssocItemsIterator<'tcx> {
2817 // Ideally, we would use `-> impl Iterator` here, but it falls
2818 // afoul of the conservative "capture [restrictions]" we put
2819 // in place, so we use a hand-written iterator.
2821 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2822 AssocItemsIterator {
2824 def_ids: self.associated_item_def_ids(def_id),
2829 /// Returns `true` if the impls are the same polarity and the trait either
2830 /// has no items or is annotated #[marker] and prevents item overrides.
2831 pub fn impls_are_allowed_to_overlap(
2835 ) -> Option<ImplOverlapKind> {
2836 // If either trait impl references an error, they're allowed to overlap,
2837 // as one of them essentially doesn't exist.
2838 if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
2839 || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
2841 return Some(ImplOverlapKind::Permitted);
2844 match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
2845 (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
2846 // `#[rustc_reservation_impl]` impls don't overlap with anything
2848 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2851 return Some(ImplOverlapKind::Permitted);
2853 (ImplPolarity::Positive, ImplPolarity::Negative)
2854 | (ImplPolarity::Negative, ImplPolarity::Positive) => {
2855 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2857 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2862 (ImplPolarity::Positive, ImplPolarity::Positive)
2863 | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
2866 let is_marker_overlap = if self.features().overlapping_marker_traits {
2867 let trait1_is_empty = self.impl_trait_ref(def_id1).map_or(false, |trait_ref| {
2868 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2870 let trait2_is_empty = self.impl_trait_ref(def_id2).map_or(false, |trait_ref| {
2871 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2873 trait1_is_empty && trait2_is_empty
2875 let is_marker_impl = |def_id: DefId| -> bool {
2876 let trait_ref = self.impl_trait_ref(def_id);
2877 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2879 is_marker_impl(def_id1) && is_marker_impl(def_id2)
2882 if is_marker_overlap {
2884 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2887 Some(ImplOverlapKind::Permitted)
2889 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2890 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2891 if self_ty1 == self_ty2 {
2893 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2896 return Some(ImplOverlapKind::Issue33140);
2899 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2900 def_id1, def_id2, self_ty1, self_ty2
2906 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
2911 /// Returns `ty::VariantDef` if `res` refers to a struct,
2912 /// or variant or their constructors, panics otherwise.
2913 pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
2915 Res::Def(DefKind::Variant, did) => {
2916 let enum_did = self.parent(did).unwrap();
2917 self.adt_def(enum_did).variant_with_id(did)
2919 Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
2920 self.adt_def(did).non_enum_variant()
2922 Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
2923 let variant_did = self.parent(variant_ctor_did).unwrap();
2924 let enum_did = self.parent(variant_did).unwrap();
2925 self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
2927 Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
2928 let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
2929 self.adt_def(struct_did).non_enum_variant()
2931 _ => bug!("expect_variant_res used with unexpected res {:?}", res),
2935 pub fn item_name(self, id: DefId) -> Symbol {
2936 if id.index == CRATE_DEF_INDEX {
2937 self.original_crate_name(id.krate)
2939 let def_key = self.def_key(id);
2940 match def_key.disambiguated_data.data {
2941 // The name of a constructor is that of its parent.
2942 hir_map::DefPathData::Ctor => {
2943 self.item_name(DefId { krate: id.krate, index: def_key.parent.unwrap() })
2945 _ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2946 bug!("item_name: no name for {:?}", self.def_path(id));
2952 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2953 pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> ReadOnlyBodyAndCache<'tcx, 'tcx> {
2955 ty::InstanceDef::Item(did) => self.optimized_mir(did).unwrap_read_only(),
2956 ty::InstanceDef::VtableShim(..)
2957 | ty::InstanceDef::ReifyShim(..)
2958 | ty::InstanceDef::Intrinsic(..)
2959 | ty::InstanceDef::FnPtrShim(..)
2960 | ty::InstanceDef::Virtual(..)
2961 | ty::InstanceDef::ClosureOnceShim { .. }
2962 | ty::InstanceDef::DropGlue(..)
2963 | ty::InstanceDef::CloneShim(..) => self.mir_shims(instance).unwrap_read_only(),
2967 /// Gets the attributes of a definition.
2968 pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
2969 if let Some(id) = self.hir().as_local_hir_id(did) {
2970 Attributes::Borrowed(self.hir().attrs(id))
2972 Attributes::Owned(self.item_attrs(did))
2976 /// Determines whether an item is annotated with an attribute.
2977 pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
2978 attr::contains_name(&self.get_attrs(did), attr)
2981 /// Returns `true` if this is an `auto trait`.
2982 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2983 self.trait_def(trait_def_id).has_auto_impl
2986 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2987 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2990 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
2991 /// If it implements no trait, returns `None`.
2992 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2993 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2996 /// If the given defid describes a method belonging to an impl, returns the
2997 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
2998 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2999 let item = if def_id.krate != LOCAL_CRATE {
3000 if let Some(DefKind::Method) = self.def_kind(def_id) {
3001 Some(self.associated_item(def_id))
3006 self.opt_associated_item(def_id)
3009 item.and_then(|trait_item| match trait_item.container {
3010 TraitContainer(_) => None,
3011 ImplContainer(def_id) => Some(def_id),
3015 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3016 /// with the name of the crate containing the impl.
3017 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3018 if impl_did.is_local() {
3019 let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
3020 Ok(self.hir().span(hir_id))
3022 Err(self.crate_name(impl_did.krate))
3026 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
3027 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3028 /// definition's parent/scope to perform comparison.
3029 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3030 // We could use `Ident::eq` here, but we deliberately don't. The name
3031 // comparison fails frequently, and we want to avoid the expensive
3032 // `modern()` calls required for the span comparison whenever possible.
3033 use_name.name == def_name.name
3037 .hygienic_eq(def_name.span.ctxt(), self.expansion_that_defined(def_parent_def_id))
3040 fn expansion_that_defined(self, scope: DefId) -> ExpnId {
3042 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3043 _ => ExpnId::root(),
3047 pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
3048 ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
3052 pub fn adjust_ident_and_get_scope(
3057 ) -> (Ident, DefId) {
3058 let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
3059 Some(actual_expansion) => {
3060 self.hir().definitions().parent_module_of_macro_def(actual_expansion)
3062 None => self.hir().get_module_parent(block),
3069 pub struct AssocItemsIterator<'tcx> {
3071 def_ids: &'tcx [DefId],
3075 impl Iterator for AssocItemsIterator<'_> {
3076 type Item = AssocItem;
3078 fn next(&mut self) -> Option<AssocItem> {
3079 let def_id = self.def_ids.get(self.next_index)?;
3080 self.next_index += 1;
3081 Some(self.tcx.associated_item(*def_id))
3085 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> AssocItem {
3086 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3087 let parent_id = tcx.hir().get_parent_item(id);
3088 let parent_def_id = tcx.hir().local_def_id(parent_id);
3089 let parent_item = tcx.hir().expect_item(parent_id);
3090 match parent_item.kind {
3091 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3092 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.hir_id == id) {
3094 tcx.associated_item_from_impl_item_ref(parent_def_id, impl_item_ref);
3095 debug_assert_eq!(assoc_item.def_id, def_id);
3100 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3101 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.hir_id == id) {
3102 let assoc_item = tcx.associated_item_from_trait_item_ref(
3107 debug_assert_eq!(assoc_item.def_id, def_id);
3117 "unexpected parent of trait or impl item or item not found: {:?}",
3122 #[derive(Clone, HashStable)]
3123 pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
3125 /// Calculates the `Sized` constraint.
3127 /// In fact, there are only a few options for the types in the constraint:
3128 /// - an obviously-unsized type
3129 /// - a type parameter or projection whose Sizedness can't be known
3130 /// - a tuple of type parameters or projections, if there are multiple
3132 /// - a Error, if a type contained itself. The representability
3133 /// check should catch this case.
3134 fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> AdtSizedConstraint<'_> {
3135 let def = tcx.adt_def(def_id);
3137 let result = tcx.mk_type_list(
3140 .flat_map(|v| v.fields.last())
3141 .flat_map(|f| def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))),
3144 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3146 AdtSizedConstraint(result)
3149 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
3150 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
3151 let item = tcx.hir().expect_item(id);
3153 hir::ItemKind::Trait(.., ref trait_item_refs) => tcx.arena.alloc_from_iter(
3156 .map(|trait_item_ref| trait_item_ref.id)
3157 .map(|id| tcx.hir().local_def_id(id.hir_id)),
3159 hir::ItemKind::Impl(.., ref impl_item_refs) => tcx.arena.alloc_from_iter(
3162 .map(|impl_item_ref| impl_item_ref.id)
3163 .map(|id| tcx.hir().local_def_id(id.hir_id)),
3165 hir::ItemKind::TraitAlias(..) => &[],
3166 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait"),
3170 fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
3171 tcx.hir().span_if_local(def_id).unwrap()
3174 /// If the given `DefId` describes an item belonging to a trait,
3175 /// returns the `DefId` of the trait that the trait item belongs to;
3176 /// otherwise, returns `None`.
3177 fn trait_of_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3178 tcx.opt_associated_item(def_id).and_then(|associated_item| match associated_item.container {
3179 TraitContainer(def_id) => Some(def_id),
3180 ImplContainer(_) => None,
3184 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3185 pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
3186 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
3187 if let Node::Item(item) = tcx.hir().get(hir_id) {
3188 if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
3189 return opaque_ty.impl_trait_fn;
3196 /// See `ParamEnv` struct definition for details.
3197 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ParamEnv<'_> {
3198 // The param_env of an impl Trait type is its defining function's param_env
3199 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3200 return param_env(tcx, parent);
3202 // Compute the bounds on Self and the type parameters.
3204 let InstantiatedPredicates { predicates } = tcx.predicates_of(def_id).instantiate_identity(tcx);
3206 // Finally, we have to normalize the bounds in the environment, in
3207 // case they contain any associated type projections. This process
3208 // can yield errors if the put in illegal associated types, like
3209 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3210 // report these errors right here; this doesn't actually feel
3211 // right to me, because constructing the environment feels like a
3212 // kind of a "idempotent" action, but I'm not sure where would be
3213 // a better place. In practice, we construct environments for
3214 // every fn once during type checking, and we'll abort if there
3215 // are any errors at that point, so after type checking you can be
3216 // sure that this will succeed without errors anyway.
3218 let unnormalized_env = ty::ParamEnv::new(
3219 tcx.intern_predicates(&predicates),
3220 traits::Reveal::UserFacing,
3221 tcx.sess.opts.debugging_opts.chalk.then_some(def_id),
3224 let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
3225 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
3227 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3228 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3231 fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
3232 assert_eq!(crate_num, LOCAL_CRATE);
3233 tcx.sess.local_crate_disambiguator()
3236 fn original_crate_name(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Symbol {
3237 assert_eq!(crate_num, LOCAL_CRATE);
3238 tcx.crate_name.clone()
3241 fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
3242 assert_eq!(crate_num, LOCAL_CRATE);
3243 tcx.hir().crate_hash
3246 fn instance_def_size_estimate<'tcx>(tcx: TyCtxt<'tcx>, instance_def: InstanceDef<'tcx>) -> usize {
3247 match instance_def {
3248 InstanceDef::Item(..) | InstanceDef::DropGlue(..) => {
3249 let mir = tcx.instance_mir(instance_def);
3250 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3252 // Estimate the size of other compiler-generated shims to be 1.
3257 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
3259 /// See [`ImplOverlapKind::Issue33140`] for more details.
3260 fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
3261 debug!("issue33140_self_ty({:?})", def_id);
3264 .impl_trait_ref(def_id)
3265 .unwrap_or_else(|| bug!("issue33140_self_ty called on inherent impl {:?}", def_id));
3267 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3269 let is_marker_like = tcx.impl_polarity(def_id) == ty::ImplPolarity::Positive
3270 && tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3272 // Check whether these impls would be ok for a marker trait.
3273 if !is_marker_like {
3274 debug!("issue33140_self_ty - not marker-like!");
3278 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3279 if trait_ref.substs.len() != 1 {
3280 debug!("issue33140_self_ty - impl has substs!");
3284 let predicates = tcx.predicates_of(def_id);
3285 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3286 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3290 let self_ty = trait_ref.self_ty();
3291 let self_ty_matches = match self_ty.kind {
3292 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3296 if self_ty_matches {
3297 debug!("issue33140_self_ty - MATCHES!");
3300 debug!("issue33140_self_ty - non-matching self type");
3305 /// Check if a function is async.
3306 fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
3309 .as_local_hir_id(def_id)
3310 .unwrap_or_else(|| bug!("asyncness: expected local `DefId`, got `{:?}`", def_id));
3312 let node = tcx.hir().get(hir_id);
3314 let fn_like = hir::map::blocks::FnLikeNode::from_node(node).unwrap_or_else(|| {
3315 bug!("asyncness: expected fn-like node but got `{:?}`", def_id);
3321 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3322 context::provide(providers);
3323 erase_regions::provide(providers);
3324 layout::provide(providers);
3325 util::provide(providers);
3326 constness::provide(providers);
3327 *providers = ty::query::Providers {
3330 associated_item_def_ids,
3331 adt_sized_constraint,
3335 crate_disambiguator,
3336 original_crate_name,
3338 trait_impls_of: trait_def::trait_impls_of_provider,
3339 instance_def_size_estimate,
3345 /// A map for the local crate mapping each type to a vector of its
3346 /// inherent impls. This is not meant to be used outside of coherence;
3347 /// rather, you should request the vector for a specific type via
3348 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3349 /// (constructing this map requires touching the entire crate).
3350 #[derive(Clone, Debug, Default, HashStable)]
3351 pub struct CrateInherentImpls {
3352 pub inherent_impls: DefIdMap<Vec<DefId>>,
3355 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
3356 pub struct SymbolName {
3357 // FIXME: we don't rely on interning or equality here - better have
3358 // this be a `&'tcx str`.
3363 pub fn new(name: &str) -> SymbolName {
3364 SymbolName { name: Symbol::intern(name) }
3368 impl PartialOrd for SymbolName {
3369 fn partial_cmp(&self, other: &SymbolName) -> Option<Ordering> {
3370 self.name.as_str().partial_cmp(&other.name.as_str())
3374 /// Ordering must use the chars to ensure reproducible builds.
3375 impl Ord for SymbolName {
3376 fn cmp(&self, other: &SymbolName) -> Ordering {
3377 self.name.as_str().cmp(&other.name.as_str())
3381 impl fmt::Display for SymbolName {
3382 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3383 fmt::Display::fmt(&self.name, fmt)
3387 impl fmt::Debug for SymbolName {
3388 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3389 fmt::Display::fmt(&self.name, fmt)