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
::exports
::ExportMap
;
10 use crate::ich
::StableHashingContext
;
11 use crate::infer
::canonical
::Canonical
;
12 use crate::middle
::cstore
::CrateStoreDyn
;
13 use crate::middle
::resolve_lifetime
::ObjectLifetimeDefault
;
14 use crate::mir
::interpret
::ErrorHandled
;
16 use crate::mir
::GeneratorLayout
;
17 use crate::traits
::{self, Reveal}
;
19 use crate::ty
::subst
::{GenericArg, InternalSubsts, Subst, SubstsRef}
;
20 use crate::ty
::util
::{Discr, IntTypeExt}
;
22 use rustc_attr
as attr
;
23 use rustc_data_structures
::captures
::Captures
;
24 use rustc_data_structures
::fingerprint
::Fingerprint
;
25 use rustc_data_structures
::fx
::FxHashMap
;
26 use rustc_data_structures
::fx
::FxHashSet
;
27 use rustc_data_structures
::fx
::FxIndexMap
;
28 use rustc_data_structures
::sorted_map
::SortedIndexMultiMap
;
29 use rustc_data_structures
::stable_hasher
::{HashStable, StableHasher}
;
30 use rustc_data_structures
::sync
::{self, par_iter, ParallelIterator}
;
31 use rustc_errors
::ErrorReported
;
33 use rustc_hir
::def
::{CtorKind, CtorOf, DefKind, Namespace, Res}
;
34 use rustc_hir
::def_id
::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX}
;
35 use rustc_hir
::lang_items
::{FnMutTraitLangItem, FnOnceTraitLangItem, FnTraitLangItem}
;
36 use rustc_hir
::{Constness, Node}
;
37 use rustc_index
::vec
::{Idx, IndexVec}
;
38 use rustc_macros
::HashStable
;
39 use rustc_serialize
::{self, Encodable, Encoder}
;
40 use rustc_session
::DataTypeKind
;
41 use rustc_span
::hygiene
::ExpnId
;
42 use rustc_span
::symbol
::{kw, sym, Ident, Symbol}
;
44 use rustc_target
::abi
::{Align, VariantIdx}
;
46 use std
::cell
::RefCell
;
47 use std
::cmp
::Ordering
;
49 use std
::hash
::{Hash, Hasher}
;
50 use std
::marker
::PhantomData
;
54 pub use self::sty
::BoundRegion
::*;
55 pub use self::sty
::InferTy
::*;
56 pub use self::sty
::RegionKind
;
57 pub use self::sty
::RegionKind
::*;
58 pub use self::sty
::TyKind
::*;
59 pub use self::sty
::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST}
;
60 pub use self::sty
::{BoundRegion, EarlyBoundRegion, FreeRegion, Region}
;
61 pub use self::sty
::{CanonicalPolyFnSig, FnSig, GenSig, PolyFnSig, PolyGenSig}
;
62 pub use self::sty
::{ClosureSubsts, GeneratorSubsts, TypeAndMut, UpvarSubsts}
;
63 pub use self::sty
::{Const, ConstKind, ExistentialProjection, PolyExistentialProjection}
;
64 pub use self::sty
::{ConstVid, FloatVid, IntVid, RegionVid, TyVid}
;
65 pub use self::sty
::{ExistentialPredicate, InferConst, InferTy, ParamConst, ParamTy, ProjectionTy}
;
66 pub use self::sty
::{ExistentialTraitRef, PolyExistentialTraitRef}
;
67 pub use self::sty
::{PolyTraitRef, TraitRef, TyKind}
;
68 pub use crate::ty
::diagnostics
::*;
70 pub use self::binding
::BindingMode
;
71 pub use self::binding
::BindingMode
::*;
73 pub use self::context
::{tls, FreeRegionInfo, TyCtxt}
;
74 pub use self::context
::{
75 CanonicalUserType
, CanonicalUserTypeAnnotation
, CanonicalUserTypeAnnotations
, ResolvedOpaqueTy
,
76 UserType
, UserTypeAnnotationIndex
,
78 pub use self::context
::{
79 CtxtInterners
, GeneratorInteriorTypeCause
, GlobalCtxt
, Lift
, TypeckTables
,
82 pub use self::instance
::{Instance, InstanceDef}
;
84 pub use self::list
::List
;
86 pub use self::trait_def
::TraitDef
;
88 pub use self::query
::queries
;
90 pub use self::consts
::ConstInt
;
103 pub mod inhabitedness
;
105 pub mod normalize_erasing_regions
;
121 mod structural_impls
;
126 pub struct ResolverOutputs
{
127 pub definitions
: rustc_hir
::definitions
::Definitions
,
128 pub cstore
: Box
<CrateStoreDyn
>,
129 pub extern_crate_map
: FxHashMap
<LocalDefId
, CrateNum
>,
130 pub maybe_unused_trait_imports
: FxHashSet
<LocalDefId
>,
131 pub maybe_unused_extern_crates
: Vec
<(LocalDefId
, Span
)>,
132 pub export_map
: ExportMap
<LocalDefId
>,
133 pub glob_map
: FxHashMap
<LocalDefId
, FxHashSet
<Symbol
>>,
134 /// Extern prelude entries. The value is `true` if the entry was introduced
135 /// via `extern crate` item and not `--extern` option or compiler built-in.
136 pub extern_prelude
: FxHashMap
<Symbol
, bool
>,
139 #[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
140 pub enum AssocItemContainer
{
141 TraitContainer(DefId
),
142 ImplContainer(DefId
),
145 impl AssocItemContainer
{
146 /// Asserts that this is the `DefId` of an associated item declared
147 /// in a trait, and returns the trait `DefId`.
148 pub fn assert_trait(&self) -> DefId
{
150 TraitContainer(id
) => id
,
151 _
=> bug
!("associated item has wrong container type: {:?}", self),
155 pub fn id(&self) -> DefId
{
157 TraitContainer(id
) => id
,
158 ImplContainer(id
) => id
,
163 /// The "header" of an impl is everything outside the body: a Self type, a trait
164 /// ref (in the case of a trait impl), and a set of predicates (from the
165 /// bounds / where-clauses).
166 #[derive(Clone, Debug, TypeFoldable)]
167 pub struct ImplHeader
<'tcx
> {
168 pub impl_def_id
: DefId
,
169 pub self_ty
: Ty
<'tcx
>,
170 pub trait_ref
: Option
<TraitRef
<'tcx
>>,
171 pub predicates
: Vec
<Predicate
<'tcx
>>,
174 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
175 pub enum ImplPolarity
{
176 /// `impl Trait for Type`
178 /// `impl !Trait for Type`
180 /// `#[rustc_reservation_impl] impl Trait for Type`
182 /// This is a "stability hack", not a real Rust feature.
183 /// See #64631 for details.
187 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
188 pub struct AssocItem
{
190 #[stable_hasher(project(name))]
194 pub defaultness
: hir
::Defaultness
,
195 pub container
: AssocItemContainer
,
197 /// Whether this is a method with an explicit self
198 /// as its first parameter, allowing method calls.
199 pub fn_has_self_parameter
: bool
,
202 #[derive(Copy, Clone, PartialEq, Debug, HashStable)]
210 pub fn namespace(&self) -> Namespace
{
212 ty
::AssocKind
::Type
=> Namespace
::TypeNS
,
213 ty
::AssocKind
::Const
| ty
::AssocKind
::Fn
=> Namespace
::ValueNS
,
217 pub fn as_def_kind(&self) -> DefKind
{
219 AssocKind
::Const
=> DefKind
::AssocConst
,
220 AssocKind
::Fn
=> DefKind
::AssocFn
,
221 AssocKind
::Type
=> DefKind
::AssocTy
,
227 pub fn signature(&self, tcx
: TyCtxt
<'_
>) -> String
{
229 ty
::AssocKind
::Fn
=> {
230 // We skip the binder here because the binder would deanonymize all
231 // late-bound regions, and we don't want method signatures to show up
232 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
233 // regions just fine, showing `fn(&MyType)`.
234 tcx
.fn_sig(self.def_id
).skip_binder().to_string()
236 ty
::AssocKind
::Type
=> format
!("type {};", self.ident
),
237 ty
::AssocKind
::Const
=> {
238 format
!("const {}: {:?};", self.ident
, tcx
.type_of(self.def_id
))
244 /// A list of `ty::AssocItem`s in definition order that allows for efficient lookup by name.
246 /// When doing lookup by name, we try to postpone hygienic comparison for as long as possible since
247 /// it is relatively expensive. Instead, items are indexed by `Symbol` and hygienic comparison is
248 /// done only on items with the same name.
249 #[derive(Debug, Clone, PartialEq, HashStable)]
250 pub struct AssociatedItems
<'tcx
> {
251 items
: SortedIndexMultiMap
<u32, Symbol
, &'tcx ty
::AssocItem
>,
254 impl<'tcx
> AssociatedItems
<'tcx
> {
255 /// Constructs an `AssociatedItems` map from a series of `ty::AssocItem`s in definition order.
256 pub fn new(items_in_def_order
: impl IntoIterator
<Item
= &'tcx ty
::AssocItem
>) -> Self {
257 let items
= items_in_def_order
.into_iter().map(|item
| (item
.ident
.name
, item
)).collect();
258 AssociatedItems { items }
261 /// Returns a slice of associated items in the order they were defined.
263 /// New code should avoid relying on definition order. If you need a particular associated item
264 /// for a known trait, make that trait a lang item instead of indexing this array.
265 pub fn in_definition_order(&self) -> impl '_
+ Iterator
<Item
= &ty
::AssocItem
> {
266 self.items
.iter().map(|(_
, v
)| *v
)
269 /// Returns an iterator over all associated items with the given name, ignoring hygiene.
270 pub fn filter_by_name_unhygienic(
273 ) -> impl '_
+ Iterator
<Item
= &ty
::AssocItem
> {
274 self.items
.get_by_key(&name
).copied()
277 /// Returns an iterator over all associated items with the given name.
279 /// Multiple items may have the same name if they are in different `Namespace`s. For example,
280 /// an associated type can have the same name as a method. Use one of the `find_by_name_and_*`
281 /// methods below if you know which item you are looking for.
282 pub fn filter_by_name(
286 parent_def_id
: DefId
,
287 ) -> impl 'a
+ Iterator
<Item
= &'a ty
::AssocItem
> {
288 self.filter_by_name_unhygienic(ident
.name
)
289 .filter(move |item
| tcx
.hygienic_eq(ident
, item
.ident
, parent_def_id
))
292 /// Returns the associated item with the given name and `AssocKind`, if one exists.
293 pub fn find_by_name_and_kind(
298 parent_def_id
: DefId
,
299 ) -> Option
<&ty
::AssocItem
> {
300 self.filter_by_name_unhygienic(ident
.name
)
301 .filter(|item
| item
.kind
== kind
)
302 .find(|item
| tcx
.hygienic_eq(ident
, item
.ident
, parent_def_id
))
305 /// Returns the associated item with the given name in the given `Namespace`, if one exists.
306 pub fn find_by_name_and_namespace(
311 parent_def_id
: DefId
,
312 ) -> Option
<&ty
::AssocItem
> {
313 self.filter_by_name_unhygienic(ident
.name
)
314 .filter(|item
| item
.kind
.namespace() == ns
)
315 .find(|item
| tcx
.hygienic_eq(ident
, item
.ident
, parent_def_id
))
319 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
320 pub enum Visibility
{
321 /// Visible everywhere (including in other crates).
323 /// Visible only in the given crate-local module.
325 /// Not visible anywhere in the local crate. This is the visibility of private external items.
329 pub trait DefIdTree
: Copy
{
330 fn parent(self, id
: DefId
) -> Option
<DefId
>;
332 fn is_descendant_of(self, mut descendant
: DefId
, ancestor
: DefId
) -> bool
{
333 if descendant
.krate
!= ancestor
.krate
{
337 while descendant
!= ancestor
{
338 match self.parent(descendant
) {
339 Some(parent
) => descendant
= parent
,
340 None
=> return false,
347 impl<'tcx
> DefIdTree
for TyCtxt
<'tcx
> {
348 fn parent(self, id
: DefId
) -> Option
<DefId
> {
349 self.def_key(id
).parent
.map(|index
| DefId { index, ..id }
)
354 pub fn from_hir(visibility
: &hir
::Visibility
<'_
>, id
: hir
::HirId
, tcx
: TyCtxt
<'_
>) -> Self {
355 match visibility
.node
{
356 hir
::VisibilityKind
::Public
=> Visibility
::Public
,
357 hir
::VisibilityKind
::Crate(_
) => Visibility
::Restricted(DefId
::local(CRATE_DEF_INDEX
)),
358 hir
::VisibilityKind
::Restricted { ref path, .. }
=> match path
.res
{
359 // If there is no resolution, `resolve` will have already reported an error, so
360 // assume that the visibility is public to avoid reporting more privacy errors.
361 Res
::Err
=> Visibility
::Public
,
362 def
=> Visibility
::Restricted(def
.def_id()),
364 hir
::VisibilityKind
::Inherited
=> {
365 Visibility
::Restricted(tcx
.parent_module(id
).to_def_id())
370 /// Returns `true` if an item with this visibility is accessible from the given block.
371 pub fn is_accessible_from
<T
: DefIdTree
>(self, module
: DefId
, tree
: T
) -> bool
{
372 let restriction
= match self {
373 // Public items are visible everywhere.
374 Visibility
::Public
=> return true,
375 // Private items from other crates are visible nowhere.
376 Visibility
::Invisible
=> return false,
377 // Restricted items are visible in an arbitrary local module.
378 Visibility
::Restricted(other
) if other
.krate
!= module
.krate
=> return false,
379 Visibility
::Restricted(module
) => module
,
382 tree
.is_descendant_of(module
, restriction
)
385 /// Returns `true` if this visibility is at least as accessible as the given visibility
386 pub fn is_at_least
<T
: DefIdTree
>(self, vis
: Visibility
, tree
: T
) -> bool
{
387 let vis_restriction
= match vis
{
388 Visibility
::Public
=> return self == Visibility
::Public
,
389 Visibility
::Invisible
=> return true,
390 Visibility
::Restricted(module
) => module
,
393 self.is_accessible_from(vis_restriction
, tree
)
396 // Returns `true` if this item is visible anywhere in the local crate.
397 pub fn is_visible_locally(self) -> bool
{
399 Visibility
::Public
=> true,
400 Visibility
::Restricted(def_id
) => def_id
.is_local(),
401 Visibility
::Invisible
=> false,
406 #[derive(Copy, Clone, PartialEq, RustcDecodable, RustcEncodable, HashStable)]
408 Covariant
, // T<A> <: T<B> iff A <: B -- e.g., function return type
409 Invariant
, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
410 Contravariant
, // T<A> <: T<B> iff B <: A -- e.g., function param type
411 Bivariant
, // T<A> <: T<B> -- e.g., unused type parameter
414 /// The crate variances map is computed during typeck and contains the
415 /// variance of every item in the local crate. You should not use it
416 /// directly, because to do so will make your pass dependent on the
417 /// HIR of every item in the local crate. Instead, use
418 /// `tcx.variances_of()` to get the variance for a *particular*
420 #[derive(HashStable)]
421 pub struct CrateVariancesMap
<'tcx
> {
422 /// For each item with generics, maps to a vector of the variance
423 /// of its generics. If an item has no generics, it will have no
425 pub variances
: FxHashMap
<DefId
, &'tcx
[ty
::Variance
]>,
429 /// `a.xform(b)` combines the variance of a context with the
430 /// variance of a type with the following meaning. If we are in a
431 /// context with variance `a`, and we encounter a type argument in
432 /// a position with variance `b`, then `a.xform(b)` is the new
433 /// variance with which the argument appears.
439 /// Here, the "ambient" variance starts as covariant. `*mut T` is
440 /// invariant with respect to `T`, so the variance in which the
441 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
442 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
443 /// respect to its type argument `T`, and hence the variance of
444 /// the `i32` here is `Invariant.xform(Covariant)`, which results
445 /// (again) in `Invariant`.
449 /// fn(*const Vec<i32>, *mut Vec<i32)
451 /// The ambient variance is covariant. A `fn` type is
452 /// contravariant with respect to its parameters, so the variance
453 /// within which both pointer types appear is
454 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
455 /// T` is covariant with respect to `T`, so the variance within
456 /// which the first `Vec<i32>` appears is
457 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
458 /// is true for its `i32` argument. In the `*mut T` case, the
459 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
460 /// and hence the outermost type is `Invariant` with respect to
461 /// `Vec<i32>` (and its `i32` argument).
463 /// Source: Figure 1 of "Taming the Wildcards:
464 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
465 pub fn xform(self, v
: ty
::Variance
) -> ty
::Variance
{
467 // Figure 1, column 1.
468 (ty
::Covariant
, ty
::Covariant
) => ty
::Covariant
,
469 (ty
::Covariant
, ty
::Contravariant
) => ty
::Contravariant
,
470 (ty
::Covariant
, ty
::Invariant
) => ty
::Invariant
,
471 (ty
::Covariant
, ty
::Bivariant
) => ty
::Bivariant
,
473 // Figure 1, column 2.
474 (ty
::Contravariant
, ty
::Covariant
) => ty
::Contravariant
,
475 (ty
::Contravariant
, ty
::Contravariant
) => ty
::Covariant
,
476 (ty
::Contravariant
, ty
::Invariant
) => ty
::Invariant
,
477 (ty
::Contravariant
, ty
::Bivariant
) => ty
::Bivariant
,
479 // Figure 1, column 3.
480 (ty
::Invariant
, _
) => ty
::Invariant
,
482 // Figure 1, column 4.
483 (ty
::Bivariant
, _
) => ty
::Bivariant
,
488 // Contains information needed to resolve types and (in the future) look up
489 // the types of AST nodes.
490 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
491 pub struct CReaderCacheKey
{
497 /// Flags that we track on types. These flags are propagated upwards
498 /// through the type during type construction, so that we can quickly check
499 /// whether the type has various kinds of types in it without recursing
500 /// over the type itself.
501 pub struct TypeFlags
: u32 {
502 // Does this have parameters? Used to determine whether substitution is
504 /// Does this have [Param]?
505 const HAS_TY_PARAM
= 1 << 0;
506 /// Does this have [ReEarlyBound]?
507 const HAS_RE_PARAM
= 1 << 1;
508 /// Does this have [ConstKind::Param]?
509 const HAS_CT_PARAM
= 1 << 2;
511 const NEEDS_SUBST
= TypeFlags
::HAS_TY_PARAM
.bits
512 | TypeFlags
::HAS_RE_PARAM
.bits
513 | TypeFlags
::HAS_CT_PARAM
.bits
;
515 /// Does this have [Infer]?
516 const HAS_TY_INFER
= 1 << 3;
517 /// Does this have [ReVar]?
518 const HAS_RE_INFER
= 1 << 4;
519 /// Does this have [ConstKind::Infer]?
520 const HAS_CT_INFER
= 1 << 5;
522 /// Does this have inference variables? Used to determine whether
523 /// inference is required.
524 const NEEDS_INFER
= TypeFlags
::HAS_TY_INFER
.bits
525 | TypeFlags
::HAS_RE_INFER
.bits
526 | TypeFlags
::HAS_CT_INFER
.bits
;
528 /// Does this have [Placeholder]?
529 const HAS_TY_PLACEHOLDER
= 1 << 6;
530 /// Does this have [RePlaceholder]?
531 const HAS_RE_PLACEHOLDER
= 1 << 7;
532 /// Does this have [ConstKind::Placeholder]?
533 const HAS_CT_PLACEHOLDER
= 1 << 8;
535 /// `true` if there are "names" of regions and so forth
536 /// that are local to a particular fn/inferctxt
537 const HAS_FREE_LOCAL_REGIONS
= 1 << 9;
539 /// `true` if there are "names" of types and regions and so forth
540 /// that are local to a particular fn
541 const HAS_FREE_LOCAL_NAMES
= TypeFlags
::HAS_TY_PARAM
.bits
542 | TypeFlags
::HAS_CT_PARAM
.bits
543 | TypeFlags
::HAS_TY_INFER
.bits
544 | TypeFlags
::HAS_CT_INFER
.bits
545 | TypeFlags
::HAS_TY_PLACEHOLDER
.bits
546 | TypeFlags
::HAS_CT_PLACEHOLDER
.bits
547 | TypeFlags
::HAS_FREE_LOCAL_REGIONS
.bits
;
549 /// Does this have [Projection]?
550 const HAS_TY_PROJECTION
= 1 << 10;
551 /// Does this have [Opaque]?
552 const HAS_TY_OPAQUE
= 1 << 11;
553 /// Does this have [ConstKind::Unevaluated]?
554 const HAS_CT_PROJECTION
= 1 << 12;
556 /// Could this type be normalized further?
557 const HAS_PROJECTION
= TypeFlags
::HAS_TY_PROJECTION
.bits
558 | TypeFlags
::HAS_TY_OPAQUE
.bits
559 | TypeFlags
::HAS_CT_PROJECTION
.bits
;
561 /// Is an error type/const reachable?
562 const HAS_ERROR
= 1 << 13;
564 /// Does this have any region that "appears free" in the type?
565 /// Basically anything but [ReLateBound] and [ReErased].
566 const HAS_FREE_REGIONS
= 1 << 14;
568 /// Does this have any [ReLateBound] regions? Used to check
569 /// if a global bound is safe to evaluate.
570 const HAS_RE_LATE_BOUND
= 1 << 15;
572 /// Does this have any [ReErased] regions?
573 const HAS_RE_ERASED
= 1 << 16;
575 /// Does this value have parameters/placeholders/inference variables which could be
576 /// replaced later, in a way that would change the results of `impl` specialization?
577 const STILL_FURTHER_SPECIALIZABLE
= 1 << 17;
581 #[allow(rustc::usage_of_ty_tykind)]
582 pub struct TyS
<'tcx
> {
583 pub kind
: TyKind
<'tcx
>,
584 pub flags
: TypeFlags
,
586 /// This is a kind of confusing thing: it stores the smallest
589 /// (a) the binder itself captures nothing but
590 /// (b) all the late-bound things within the type are captured
591 /// by some sub-binder.
593 /// So, for a type without any late-bound things, like `u32`, this
594 /// will be *innermost*, because that is the innermost binder that
595 /// captures nothing. But for a type `&'D u32`, where `'D` is a
596 /// late-bound region with De Bruijn index `D`, this would be `D + 1`
597 /// -- the binder itself does not capture `D`, but `D` is captured
598 /// by an inner binder.
600 /// We call this concept an "exclusive" binder `D` because all
601 /// De Bruijn indices within the type are contained within `0..D`
603 outer_exclusive_binder
: ty
::DebruijnIndex
,
606 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
607 #[cfg(target_arch = "x86_64")]
608 static_assert_size
!(TyS
<'_
>, 32);
610 impl<'tcx
> Ord
for TyS
<'tcx
> {
611 fn cmp(&self, other
: &TyS
<'tcx
>) -> Ordering
{
612 self.kind
.cmp(&other
.kind
)
616 impl<'tcx
> PartialOrd
for TyS
<'tcx
> {
617 fn partial_cmp(&self, other
: &TyS
<'tcx
>) -> Option
<Ordering
> {
618 Some(self.kind
.cmp(&other
.kind
))
622 impl<'tcx
> PartialEq
for TyS
<'tcx
> {
624 fn eq(&self, other
: &TyS
<'tcx
>) -> bool
{
628 impl<'tcx
> Eq
for TyS
<'tcx
> {}
630 impl<'tcx
> Hash
for TyS
<'tcx
> {
631 fn hash
<H
: Hasher
>(&self, s
: &mut H
) {
632 (self as *const TyS
<'_
>).hash(s
)
636 impl<'a
, 'tcx
> HashStable
<StableHashingContext
<'a
>> for TyS
<'tcx
> {
637 fn hash_stable(&self, hcx
: &mut StableHashingContext
<'a
>, hasher
: &mut StableHasher
) {
641 // The other fields just provide fast access to information that is
642 // also contained in `kind`, so no need to hash them.
645 outer_exclusive_binder
: _
,
648 kind
.hash_stable(hcx
, hasher
);
652 #[rustc_diagnostic_item = "Ty"]
653 pub type Ty
<'tcx
> = &'tcx TyS
<'tcx
>;
655 impl<'tcx
> rustc_serialize
::UseSpecializedEncodable
for Ty
<'tcx
> {}
656 impl<'tcx
> rustc_serialize
::UseSpecializedDecodable
for Ty
<'tcx
> {}
657 impl<'tcx
> rustc_serialize
::UseSpecializedDecodable
for &'tcx List
<Ty
<'tcx
>> {}
659 pub type CanonicalTy
<'tcx
> = Canonical
<'tcx
, Ty
<'tcx
>>;
661 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
662 pub struct UpvarPath
{
663 pub hir_id
: hir
::HirId
,
666 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
667 /// the original var ID (that is, the root variable that is referenced
668 /// by the upvar) and the ID of the closure expression.
669 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
671 pub var_path
: UpvarPath
,
672 pub closure_expr_id
: LocalDefId
,
675 #[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
676 pub enum BorrowKind
{
677 /// Data must be immutable and is aliasable.
680 /// Data must be immutable but not aliasable. This kind of borrow
681 /// cannot currently be expressed by the user and is used only in
682 /// implicit closure bindings. It is needed when the closure
683 /// is borrowing or mutating a mutable referent, e.g.:
685 /// let x: &mut isize = ...;
686 /// let y = || *x += 5;
688 /// If we were to try to translate this closure into a more explicit
689 /// form, we'd encounter an error with the code as written:
691 /// struct Env { x: & &mut isize }
692 /// let x: &mut isize = ...;
693 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
694 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
696 /// This is then illegal because you cannot mutate a `&mut` found
697 /// in an aliasable location. To solve, you'd have to translate with
698 /// an `&mut` borrow:
700 /// struct Env { x: & &mut isize }
701 /// let x: &mut isize = ...;
702 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
703 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
705 /// Now the assignment to `**env.x` is legal, but creating a
706 /// mutable pointer to `x` is not because `x` is not mutable. We
707 /// could fix this by declaring `x` as `let mut x`. This is ok in
708 /// user code, if awkward, but extra weird for closures, since the
709 /// borrow is hidden.
711 /// So we introduce a "unique imm" borrow -- the referent is
712 /// immutable, but not aliasable. This solves the problem. For
713 /// simplicity, we don't give users the way to express this
714 /// borrow, it's just used when translating closures.
717 /// Data is mutable and not aliasable.
721 /// Information describing the capture of an upvar. This is computed
722 /// during `typeck`, specifically by `regionck`.
723 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
724 pub enum UpvarCapture
<'tcx
> {
725 /// Upvar is captured by value. This is always true when the
726 /// closure is labeled `move`, but can also be true in other cases
727 /// depending on inference.
730 /// Upvar is captured by reference.
731 ByRef(UpvarBorrow
<'tcx
>),
734 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
735 pub struct UpvarBorrow
<'tcx
> {
736 /// The kind of borrow: by-ref upvars have access to shared
737 /// immutable borrows, which are not part of the normal language
739 pub kind
: BorrowKind
,
741 /// Region of the resulting reference.
742 pub region
: ty
::Region
<'tcx
>,
745 pub type UpvarListMap
= FxHashMap
<DefId
, FxIndexMap
<hir
::HirId
, UpvarId
>>;
746 pub type UpvarCaptureMap
<'tcx
> = FxHashMap
<UpvarId
, UpvarCapture
<'tcx
>>;
748 #[derive(Clone, Copy, PartialEq, Eq)]
749 pub enum IntVarValue
{
751 UintType(ast
::UintTy
),
754 #[derive(Clone, Copy, PartialEq, Eq)]
755 pub struct FloatVarValue(pub ast
::FloatTy
);
757 impl ty
::EarlyBoundRegion
{
758 pub fn to_bound_region(&self) -> ty
::BoundRegion
{
759 ty
::BoundRegion
::BrNamed(self.def_id
, self.name
)
762 /// Does this early bound region have a name? Early bound regions normally
763 /// always have names except when using anonymous lifetimes (`'_`).
764 pub fn has_name(&self) -> bool
{
765 self.name
!= kw
::UnderscoreLifetime
769 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
770 pub enum GenericParamDefKind
{
774 object_lifetime_default
: ObjectLifetimeDefault
,
775 synthetic
: Option
<hir
::SyntheticTyParamKind
>,
780 impl GenericParamDefKind
{
781 pub fn descr(&self) -> &'
static str {
783 GenericParamDefKind
::Lifetime
=> "lifetime",
784 GenericParamDefKind
::Type { .. }
=> "type",
785 GenericParamDefKind
::Const
=> "constant",
790 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
791 pub struct GenericParamDef
{
796 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
797 /// on generic parameter `'a`/`T`, asserts data behind the parameter
798 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
799 pub pure_wrt_drop
: bool
,
801 pub kind
: GenericParamDefKind
,
804 impl GenericParamDef
{
805 pub fn to_early_bound_region_data(&self) -> ty
::EarlyBoundRegion
{
806 if let GenericParamDefKind
::Lifetime
= self.kind
{
807 ty
::EarlyBoundRegion { def_id: self.def_id, index: self.index, name: self.name }
809 bug
!("cannot convert a non-lifetime parameter def to an early bound region")
813 pub fn to_bound_region(&self) -> ty
::BoundRegion
{
814 if let GenericParamDefKind
::Lifetime
= self.kind
{
815 self.to_early_bound_region_data().to_bound_region()
817 bug
!("cannot convert a non-lifetime parameter def to an early bound region")
823 pub struct GenericParamCount
{
824 pub lifetimes
: usize,
829 /// Information about the formal type/lifetime parameters associated
830 /// with an item or method. Analogous to `hir::Generics`.
832 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
833 /// `Self` (optionally), `Lifetime` params..., `Type` params...
834 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
835 pub struct Generics
{
836 pub parent
: Option
<DefId
>,
837 pub parent_count
: usize,
838 pub params
: Vec
<GenericParamDef
>,
840 /// Reverse map to the `index` field of each `GenericParamDef`.
841 #[stable_hasher(ignore)]
842 pub param_def_id_to_index
: FxHashMap
<DefId
, u32>,
845 pub has_late_bound_regions
: Option
<Span
>,
848 impl<'tcx
> Generics
{
849 pub fn count(&self) -> usize {
850 self.parent_count
+ self.params
.len()
853 pub fn own_counts(&self) -> GenericParamCount
{
854 // We could cache this as a property of `GenericParamCount`, but
855 // the aim is to refactor this away entirely eventually and the
856 // presence of this method will be a constant reminder.
857 let mut own_counts
: GenericParamCount
= Default
::default();
859 for param
in &self.params
{
861 GenericParamDefKind
::Lifetime
=> own_counts
.lifetimes
+= 1,
862 GenericParamDefKind
::Type { .. }
=> own_counts
.types
+= 1,
863 GenericParamDefKind
::Const
=> own_counts
.consts
+= 1,
870 pub fn requires_monomorphization(&self, tcx
: TyCtxt
<'tcx
>) -> bool
{
871 if self.own_requires_monomorphization() {
875 if let Some(parent_def_id
) = self.parent
{
876 let parent
= tcx
.generics_of(parent_def_id
);
877 parent
.requires_monomorphization(tcx
)
883 pub fn own_requires_monomorphization(&self) -> bool
{
884 for param
in &self.params
{
886 GenericParamDefKind
::Type { .. }
| GenericParamDefKind
::Const
=> return true,
887 GenericParamDefKind
::Lifetime
=> {}
893 pub fn param_at(&'tcx
self, param_index
: usize, tcx
: TyCtxt
<'tcx
>) -> &'tcx GenericParamDef
{
894 if let Some(index
) = param_index
.checked_sub(self.parent_count
) {
897 tcx
.generics_of(self.parent
.expect("parent_count > 0 but no parent?"))
898 .param_at(param_index
, tcx
)
904 param
: &EarlyBoundRegion
,
906 ) -> &'tcx GenericParamDef
{
907 let param
= self.param_at(param
.index
as usize, tcx
);
909 GenericParamDefKind
::Lifetime
=> param
,
910 _
=> bug
!("expected lifetime parameter, but found another generic parameter"),
914 /// Returns the `GenericParamDef` associated with this `ParamTy`.
915 pub fn type_param(&'tcx
self, param
: &ParamTy
, tcx
: TyCtxt
<'tcx
>) -> &'tcx GenericParamDef
{
916 let param
= self.param_at(param
.index
as usize, tcx
);
918 GenericParamDefKind
::Type { .. }
=> param
,
919 _
=> bug
!("expected type parameter, but found another generic parameter"),
923 /// Returns the `ConstParameterDef` associated with this `ParamConst`.
924 pub fn const_param(&'tcx
self, param
: &ParamConst
, tcx
: TyCtxt
<'tcx
>) -> &GenericParamDef
{
925 let param
= self.param_at(param
.index
as usize, tcx
);
927 GenericParamDefKind
::Const
=> param
,
928 _
=> bug
!("expected const parameter, but found another generic parameter"),
933 /// Bounds on generics.
934 #[derive(Copy, Clone, Default, Debug, RustcEncodable, RustcDecodable, HashStable)]
935 pub struct GenericPredicates
<'tcx
> {
936 pub parent
: Option
<DefId
>,
937 pub predicates
: &'tcx
[(Predicate
<'tcx
>, Span
)],
940 impl<'tcx
> GenericPredicates
<'tcx
> {
944 substs
: SubstsRef
<'tcx
>,
945 ) -> InstantiatedPredicates
<'tcx
> {
946 let mut instantiated
= InstantiatedPredicates
::empty();
947 self.instantiate_into(tcx
, &mut instantiated
, substs
);
951 pub fn instantiate_own(
954 substs
: SubstsRef
<'tcx
>,
955 ) -> InstantiatedPredicates
<'tcx
> {
956 InstantiatedPredicates
{
957 predicates
: self.predicates
.iter().map(|(p
, _
)| p
.subst(tcx
, substs
)).collect(),
958 spans
: self.predicates
.iter().map(|(_
, sp
)| *sp
).collect(),
965 instantiated
: &mut InstantiatedPredicates
<'tcx
>,
966 substs
: SubstsRef
<'tcx
>,
968 if let Some(def_id
) = self.parent
{
969 tcx
.predicates_of(def_id
).instantiate_into(tcx
, instantiated
, substs
);
971 instantiated
.predicates
.extend(self.predicates
.iter().map(|(p
, _
)| p
.subst(tcx
, substs
)));
972 instantiated
.spans
.extend(self.predicates
.iter().map(|(_
, sp
)| *sp
));
975 pub fn instantiate_identity(&self, tcx
: TyCtxt
<'tcx
>) -> InstantiatedPredicates
<'tcx
> {
976 let mut instantiated
= InstantiatedPredicates
::empty();
977 self.instantiate_identity_into(tcx
, &mut instantiated
);
981 fn instantiate_identity_into(
984 instantiated
: &mut InstantiatedPredicates
<'tcx
>,
986 if let Some(def_id
) = self.parent
{
987 tcx
.predicates_of(def_id
).instantiate_identity_into(tcx
, instantiated
);
989 instantiated
.predicates
.extend(self.predicates
.iter().map(|(p
, _
)| p
));
990 instantiated
.spans
.extend(self.predicates
.iter().map(|(_
, s
)| s
));
993 pub fn instantiate_supertrait(
996 poly_trait_ref
: &ty
::PolyTraitRef
<'tcx
>,
997 ) -> InstantiatedPredicates
<'tcx
> {
998 assert_eq
!(self.parent
, None
);
999 InstantiatedPredicates
{
1003 .map(|(pred
, _
)| pred
.subst_supertrait(tcx
, poly_trait_ref
))
1005 spans
: self.predicates
.iter().map(|(_
, sp
)| *sp
).collect(),
1011 crate struct PredicateInner
<'tcx
> {
1012 kind
: PredicateKind
<'tcx
>,
1014 /// See the comment for the corresponding field of [TyS].
1015 outer_exclusive_binder
: ty
::DebruijnIndex
,
1018 #[cfg(target_arch = "x86_64")]
1019 static_assert_size
!(PredicateInner
<'_
>, 40);
1021 #[derive(Clone, Copy, Lift)]
1022 pub struct Predicate
<'tcx
> {
1023 inner
: &'tcx PredicateInner
<'tcx
>,
1026 impl rustc_serialize
::UseSpecializedEncodable
for Predicate
<'_
> {}
1027 impl rustc_serialize
::UseSpecializedDecodable
for Predicate
<'_
> {}
1029 impl<'tcx
> PartialEq
for Predicate
<'tcx
> {
1030 fn eq(&self, other
: &Self) -> bool
{
1031 // `self.kind` is always interned.
1032 ptr
::eq(self.inner
, other
.inner
)
1036 impl Hash
for Predicate
<'_
> {
1037 fn hash
<H
: Hasher
>(&self, s
: &mut H
) {
1038 (self.inner
as *const PredicateInner
<'_
>).hash(s
)
1042 impl<'tcx
> Eq
for Predicate
<'tcx
> {}
1044 impl<'tcx
> Predicate
<'tcx
> {
1046 pub fn kind(self) -> &'tcx PredicateKind
<'tcx
> {
1051 impl<'a
, 'tcx
> HashStable
<StableHashingContext
<'a
>> for Predicate
<'tcx
> {
1052 fn hash_stable(&self, hcx
: &mut StableHashingContext
<'a
>, hasher
: &mut StableHasher
) {
1053 let PredicateInner
{
1056 // The other fields just provide fast access to information that is
1057 // also contained in `kind`, so no need to hash them.
1059 outer_exclusive_binder
: _
,
1062 kind
.hash_stable(hcx
, hasher
);
1066 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1067 #[derive(HashStable, TypeFoldable)]
1068 pub enum PredicateKind
<'tcx
> {
1069 /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
1070 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1071 /// would be the type parameters.
1073 /// A trait predicate will have `Constness::Const` if it originates
1074 /// from a bound on a `const fn` without the `?const` opt-out (e.g.,
1075 /// `const fn foobar<Foo: Bar>() {}`).
1076 Trait(PolyTraitPredicate
<'tcx
>, Constness
),
1079 RegionOutlives(PolyRegionOutlivesPredicate
<'tcx
>),
1082 TypeOutlives(PolyTypeOutlivesPredicate
<'tcx
>),
1084 /// `where <T as TraitRef>::Name == X`, approximately.
1085 /// See the `ProjectionPredicate` struct for details.
1086 Projection(PolyProjectionPredicate
<'tcx
>),
1088 /// No syntax: `T` well-formed.
1089 WellFormed(GenericArg
<'tcx
>),
1091 /// Trait must be object-safe.
1094 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1095 /// for some substitutions `...` and `T` being a closure type.
1096 /// Satisfied (or refuted) once we know the closure's kind.
1097 ClosureKind(DefId
, SubstsRef
<'tcx
>, ClosureKind
),
1100 Subtype(PolySubtypePredicate
<'tcx
>),
1102 /// Constant initializer must evaluate successfully.
1103 ConstEvaluatable(DefId
, SubstsRef
<'tcx
>),
1105 /// Constants must be equal. The first component is the const that is expected.
1106 ConstEquate(&'tcx Const
<'tcx
>, &'tcx Const
<'tcx
>),
1109 /// The crate outlives map is computed during typeck and contains the
1110 /// outlives of every item in the local crate. You should not use it
1111 /// directly, because to do so will make your pass dependent on the
1112 /// HIR of every item in the local crate. Instead, use
1113 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1115 #[derive(HashStable)]
1116 pub struct CratePredicatesMap
<'tcx
> {
1117 /// For each struct with outlive bounds, maps to a vector of the
1118 /// predicate of its outlive bounds. If an item has no outlives
1119 /// bounds, it will have no entry.
1120 pub predicates
: FxHashMap
<DefId
, &'tcx
[(ty
::Predicate
<'tcx
>, Span
)]>,
1123 impl<'tcx
> Predicate
<'tcx
> {
1124 /// Performs a substitution suitable for going from a
1125 /// poly-trait-ref to supertraits that must hold if that
1126 /// poly-trait-ref holds. This is slightly different from a normal
1127 /// substitution in terms of what happens with bound regions. See
1128 /// lengthy comment below for details.
1129 pub fn subst_supertrait(
1132 trait_ref
: &ty
::PolyTraitRef
<'tcx
>,
1133 ) -> ty
::Predicate
<'tcx
> {
1134 // The interaction between HRTB and supertraits is not entirely
1135 // obvious. Let me walk you (and myself) through an example.
1137 // Let's start with an easy case. Consider two traits:
1139 // trait Foo<'a>: Bar<'a,'a> { }
1140 // trait Bar<'b,'c> { }
1142 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1143 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1144 // knew that `Foo<'x>` (for any 'x) then we also know that
1145 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1146 // normal substitution.
1148 // In terms of why this is sound, the idea is that whenever there
1149 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1150 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1151 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1154 // Another example to be careful of is this:
1156 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1157 // trait Bar1<'b,'c> { }
1159 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1160 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1161 // reason is similar to the previous example: any impl of
1162 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1163 // basically we would want to collapse the bound lifetimes from
1164 // the input (`trait_ref`) and the supertraits.
1166 // To achieve this in practice is fairly straightforward. Let's
1167 // consider the more complicated scenario:
1169 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1170 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1171 // where both `'x` and `'b` would have a DB index of 1.
1172 // The substitution from the input trait-ref is therefore going to be
1173 // `'a => 'x` (where `'x` has a DB index of 1).
1174 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1175 // early-bound parameter and `'b' is a late-bound parameter with a
1177 // - If we replace `'a` with `'x` from the input, it too will have
1178 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1179 // just as we wanted.
1181 // There is only one catch. If we just apply the substitution `'a
1182 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1183 // adjust the DB index because we substituting into a binder (it
1184 // tries to be so smart...) resulting in `for<'x> for<'b>
1185 // Bar1<'x,'b>` (we have no syntax for this, so use your
1186 // imagination). Basically the 'x will have DB index of 2 and 'b
1187 // will have DB index of 1. Not quite what we want. So we apply
1188 // the substitution to the *contents* of the trait reference,
1189 // rather than the trait reference itself (put another way, the
1190 // substitution code expects equal binding levels in the values
1191 // from the substitution and the value being substituted into, and
1192 // this trick achieves that).
1194 let substs
= &trait_ref
.skip_binder().substs
;
1195 let kind
= self.kind();
1196 let new
= match kind
{
1197 &PredicateKind
::Trait(ref binder
, constness
) => {
1198 PredicateKind
::Trait(binder
.map_bound(|data
| data
.subst(tcx
, substs
)), constness
)
1200 PredicateKind
::Subtype(binder
) => {
1201 PredicateKind
::Subtype(binder
.map_bound(|data
| data
.subst(tcx
, substs
)))
1203 PredicateKind
::RegionOutlives(binder
) => {
1204 PredicateKind
::RegionOutlives(binder
.map_bound(|data
| data
.subst(tcx
, substs
)))
1206 PredicateKind
::TypeOutlives(binder
) => {
1207 PredicateKind
::TypeOutlives(binder
.map_bound(|data
| data
.subst(tcx
, substs
)))
1209 PredicateKind
::Projection(binder
) => {
1210 PredicateKind
::Projection(binder
.map_bound(|data
| data
.subst(tcx
, substs
)))
1212 &PredicateKind
::WellFormed(data
) => PredicateKind
::WellFormed(data
.subst(tcx
, substs
)),
1213 &PredicateKind
::ObjectSafe(trait_def_id
) => PredicateKind
::ObjectSafe(trait_def_id
),
1214 &PredicateKind
::ClosureKind(closure_def_id
, closure_substs
, kind
) => {
1215 PredicateKind
::ClosureKind(closure_def_id
, closure_substs
.subst(tcx
, substs
), kind
)
1217 &PredicateKind
::ConstEvaluatable(def_id
, const_substs
) => {
1218 PredicateKind
::ConstEvaluatable(def_id
, const_substs
.subst(tcx
, substs
))
1220 PredicateKind
::ConstEquate(c1
, c2
) => {
1221 PredicateKind
::ConstEquate(c1
.subst(tcx
, substs
), c2
.subst(tcx
, substs
))
1225 if new
!= *kind { new.to_predicate(tcx) }
else { self }
1229 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1230 #[derive(HashStable, TypeFoldable)]
1231 pub struct TraitPredicate
<'tcx
> {
1232 pub trait_ref
: TraitRef
<'tcx
>,
1235 pub type PolyTraitPredicate
<'tcx
> = ty
::Binder
<TraitPredicate
<'tcx
>>;
1237 impl<'tcx
> TraitPredicate
<'tcx
> {
1238 pub fn def_id(self) -> DefId
{
1239 self.trait_ref
.def_id
1242 pub fn self_ty(self) -> Ty
<'tcx
> {
1243 self.trait_ref
.self_ty()
1247 impl<'tcx
> PolyTraitPredicate
<'tcx
> {
1248 pub fn def_id(self) -> DefId
{
1249 // Ok to skip binder since trait `DefId` does not care about regions.
1250 self.skip_binder().def_id()
1254 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1255 #[derive(HashStable, TypeFoldable)]
1256 pub struct OutlivesPredicate
<A
, B
>(pub A
, pub B
); // `A: B`
1257 pub type PolyOutlivesPredicate
<A
, B
> = ty
::Binder
<OutlivesPredicate
<A
, B
>>;
1258 pub type RegionOutlivesPredicate
<'tcx
> = OutlivesPredicate
<ty
::Region
<'tcx
>, ty
::Region
<'tcx
>>;
1259 pub type TypeOutlivesPredicate
<'tcx
> = OutlivesPredicate
<Ty
<'tcx
>, ty
::Region
<'tcx
>>;
1260 pub type PolyRegionOutlivesPredicate
<'tcx
> = ty
::Binder
<RegionOutlivesPredicate
<'tcx
>>;
1261 pub type PolyTypeOutlivesPredicate
<'tcx
> = ty
::Binder
<TypeOutlivesPredicate
<'tcx
>>;
1263 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1264 #[derive(HashStable, TypeFoldable)]
1265 pub struct SubtypePredicate
<'tcx
> {
1266 pub a_is_expected
: bool
,
1270 pub type PolySubtypePredicate
<'tcx
> = ty
::Binder
<SubtypePredicate
<'tcx
>>;
1272 /// This kind of predicate has no *direct* correspondent in the
1273 /// syntax, but it roughly corresponds to the syntactic forms:
1275 /// 1. `T: TraitRef<..., Item = Type>`
1276 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1278 /// In particular, form #1 is "desugared" to the combination of a
1279 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1280 /// predicates. Form #2 is a broader form in that it also permits
1281 /// equality between arbitrary types. Processing an instance of
1282 /// Form #2 eventually yields one of these `ProjectionPredicate`
1283 /// instances to normalize the LHS.
1284 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1285 #[derive(HashStable, TypeFoldable)]
1286 pub struct ProjectionPredicate
<'tcx
> {
1287 pub projection_ty
: ProjectionTy
<'tcx
>,
1291 pub type PolyProjectionPredicate
<'tcx
> = Binder
<ProjectionPredicate
<'tcx
>>;
1293 impl<'tcx
> PolyProjectionPredicate
<'tcx
> {
1294 /// Returns the `DefId` of the associated item being projected.
1295 pub fn item_def_id(&self) -> DefId
{
1296 self.skip_binder().projection_ty
.item_def_id
1300 pub fn to_poly_trait_ref(&self, tcx
: TyCtxt
<'tcx
>) -> PolyTraitRef
<'tcx
> {
1301 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1302 // `self.0.trait_ref` is permitted to have escaping regions.
1303 // This is because here `self` has a `Binder` and so does our
1304 // return value, so we are preserving the number of binding
1306 self.map_bound(|predicate
| predicate
.projection_ty
.trait_ref(tcx
))
1309 pub fn ty(&self) -> Binder
<Ty
<'tcx
>> {
1310 self.map_bound(|predicate
| predicate
.ty
)
1313 /// The `DefId` of the `TraitItem` for the associated type.
1315 /// Note that this is not the `DefId` of the `TraitRef` containing this
1316 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1317 pub fn projection_def_id(&self) -> DefId
{
1318 // Ok to skip binder since trait `DefId` does not care about regions.
1319 self.skip_binder().projection_ty
.item_def_id
1323 pub trait ToPolyTraitRef
<'tcx
> {
1324 fn to_poly_trait_ref(&self) -> PolyTraitRef
<'tcx
>;
1327 impl<'tcx
> ToPolyTraitRef
<'tcx
> for TraitRef
<'tcx
> {
1328 fn to_poly_trait_ref(&self) -> PolyTraitRef
<'tcx
> {
1329 ty
::Binder
::dummy(*self)
1333 impl<'tcx
> ToPolyTraitRef
<'tcx
> for PolyTraitPredicate
<'tcx
> {
1334 fn to_poly_trait_ref(&self) -> PolyTraitRef
<'tcx
> {
1335 self.map_bound_ref(|trait_pred
| trait_pred
.trait_ref
)
1339 pub trait ToPredicate
<'tcx
> {
1340 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
>;
1343 impl ToPredicate
<'tcx
> for PredicateKind
<'tcx
> {
1345 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1346 tcx
.mk_predicate(self)
1350 impl<'tcx
> ToPredicate
<'tcx
> for ConstnessAnd
<TraitRef
<'tcx
>> {
1351 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1352 ty
::PredicateKind
::Trait(
1353 ty
::Binder
::dummy(ty
::TraitPredicate { trait_ref: self.value }
),
1360 impl<'tcx
> ToPredicate
<'tcx
> for ConstnessAnd
<&TraitRef
<'tcx
>> {
1361 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1362 ty
::PredicateKind
::Trait(
1363 ty
::Binder
::dummy(ty
::TraitPredicate { trait_ref: *self.value }
),
1370 impl<'tcx
> ToPredicate
<'tcx
> for ConstnessAnd
<PolyTraitRef
<'tcx
>> {
1371 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1372 ty
::PredicateKind
::Trait(self.value
.to_poly_trait_predicate(), self.constness
)
1377 impl<'tcx
> ToPredicate
<'tcx
> for ConstnessAnd
<&PolyTraitRef
<'tcx
>> {
1378 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1379 ty
::PredicateKind
::Trait(self.value
.to_poly_trait_predicate(), self.constness
)
1384 impl<'tcx
> ToPredicate
<'tcx
> for PolyRegionOutlivesPredicate
<'tcx
> {
1385 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1386 PredicateKind
::RegionOutlives(self).to_predicate(tcx
)
1390 impl<'tcx
> ToPredicate
<'tcx
> for PolyTypeOutlivesPredicate
<'tcx
> {
1391 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1392 PredicateKind
::TypeOutlives(self).to_predicate(tcx
)
1396 impl<'tcx
> ToPredicate
<'tcx
> for PolyProjectionPredicate
<'tcx
> {
1397 fn to_predicate(self, tcx
: TyCtxt
<'tcx
>) -> Predicate
<'tcx
> {
1398 PredicateKind
::Projection(self).to_predicate(tcx
)
1402 impl<'tcx
> Predicate
<'tcx
> {
1403 pub fn to_opt_poly_trait_ref(self) -> Option
<PolyTraitRef
<'tcx
>> {
1405 &PredicateKind
::Trait(ref t
, _
) => Some(t
.to_poly_trait_ref()),
1406 PredicateKind
::Projection(..)
1407 | PredicateKind
::Subtype(..)
1408 | PredicateKind
::RegionOutlives(..)
1409 | PredicateKind
::WellFormed(..)
1410 | PredicateKind
::ObjectSafe(..)
1411 | PredicateKind
::ClosureKind(..)
1412 | PredicateKind
::TypeOutlives(..)
1413 | PredicateKind
::ConstEvaluatable(..)
1414 | PredicateKind
::ConstEquate(..) => None
,
1418 pub fn to_opt_type_outlives(self) -> Option
<PolyTypeOutlivesPredicate
<'tcx
>> {
1420 &PredicateKind
::TypeOutlives(data
) => Some(data
),
1421 PredicateKind
::Trait(..)
1422 | PredicateKind
::Projection(..)
1423 | PredicateKind
::Subtype(..)
1424 | PredicateKind
::RegionOutlives(..)
1425 | PredicateKind
::WellFormed(..)
1426 | PredicateKind
::ObjectSafe(..)
1427 | PredicateKind
::ClosureKind(..)
1428 | PredicateKind
::ConstEvaluatable(..)
1429 | PredicateKind
::ConstEquate(..) => None
,
1434 /// Represents the bounds declared on a particular set of type
1435 /// parameters. Should eventually be generalized into a flag list of
1436 /// where-clauses. You can obtain a `InstantiatedPredicates` list from a
1437 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1438 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1439 /// the `GenericPredicates` are expressed in terms of the bound type
1440 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1441 /// represented a set of bounds for some particular instantiation,
1442 /// meaning that the generic parameters have been substituted with
1447 /// struct Foo<T, U: Bar<T>> { ... }
1449 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1450 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1451 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1452 /// [usize:Bar<isize>]]`.
1453 #[derive(Clone, Debug, TypeFoldable)]
1454 pub struct InstantiatedPredicates
<'tcx
> {
1455 pub predicates
: Vec
<Predicate
<'tcx
>>,
1456 pub spans
: Vec
<Span
>,
1459 impl<'tcx
> InstantiatedPredicates
<'tcx
> {
1460 pub fn empty() -> InstantiatedPredicates
<'tcx
> {
1461 InstantiatedPredicates { predicates: vec![], spans: vec![] }
1464 pub fn is_empty(&self) -> bool
{
1465 self.predicates
.is_empty()
1469 rustc_index
::newtype_index
! {
1470 /// "Universes" are used during type- and trait-checking in the
1471 /// presence of `for<..>` binders to control what sets of names are
1472 /// visible. Universes are arranged into a tree: the root universe
1473 /// contains names that are always visible. Each child then adds a new
1474 /// set of names that are visible, in addition to those of its parent.
1475 /// We say that the child universe "extends" the parent universe with
1478 /// To make this more concrete, consider this program:
1482 /// fn bar<T>(x: T) {
1483 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1487 /// The struct name `Foo` is in the root universe U0. But the type
1488 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1489 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1490 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1491 /// region `'a` is in a universe U2 that extends U1, because we can
1492 /// name it inside the fn type but not outside.
1494 /// Universes are used to do type- and trait-checking around these
1495 /// "forall" binders (also called **universal quantification**). The
1496 /// idea is that when, in the body of `bar`, we refer to `T` as a
1497 /// type, we aren't referring to any type in particular, but rather a
1498 /// kind of "fresh" type that is distinct from all other types we have
1499 /// actually declared. This is called a **placeholder** type, and we
1500 /// use universes to talk about this. In other words, a type name in
1501 /// universe 0 always corresponds to some "ground" type that the user
1502 /// declared, but a type name in a non-zero universe is a placeholder
1503 /// type -- an idealized representative of "types in general" that we
1504 /// use for checking generic functions.
1505 pub struct UniverseIndex
{
1507 DEBUG_FORMAT
= "U{}",
1511 impl UniverseIndex
{
1512 pub const ROOT
: UniverseIndex
= UniverseIndex
::from_u32(0);
1514 /// Returns the "next" universe index in order -- this new index
1515 /// is considered to extend all previous universes. This
1516 /// corresponds to entering a `forall` quantifier. So, for
1517 /// example, suppose we have this type in universe `U`:
1520 /// for<'a> fn(&'a u32)
1523 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1524 /// new universe that extends `U` -- in this new universe, we can
1525 /// name the region `'a`, but that region was not nameable from
1526 /// `U` because it was not in scope there.
1527 pub fn next_universe(self) -> UniverseIndex
{
1528 UniverseIndex
::from_u32(self.private
.checked_add(1).unwrap())
1531 /// Returns `true` if `self` can name a name from `other` -- in other words,
1532 /// if the set of names in `self` is a superset of those in
1533 /// `other` (`self >= other`).
1534 pub fn can_name(self, other
: UniverseIndex
) -> bool
{
1535 self.private
>= other
.private
1538 /// Returns `true` if `self` cannot name some names from `other` -- in other
1539 /// words, if the set of names in `self` is a strict subset of
1540 /// those in `other` (`self < other`).
1541 pub fn cannot_name(self, other
: UniverseIndex
) -> bool
{
1542 self.private
< other
.private
1546 /// The "placeholder index" fully defines a placeholder region.
1547 /// Placeholder regions are identified by both a **universe** as well
1548 /// as a "bound-region" within that universe. The `bound_region` is
1549 /// basically a name -- distinct bound regions within the same
1550 /// universe are just two regions with an unknown relationship to one
1552 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1553 pub struct Placeholder
<T
> {
1554 pub universe
: UniverseIndex
,
1558 impl<'a
, T
> HashStable
<StableHashingContext
<'a
>> for Placeholder
<T
>
1560 T
: HashStable
<StableHashingContext
<'a
>>,
1562 fn hash_stable(&self, hcx
: &mut StableHashingContext
<'a
>, hasher
: &mut StableHasher
) {
1563 self.universe
.hash_stable(hcx
, hasher
);
1564 self.name
.hash_stable(hcx
, hasher
);
1568 pub type PlaceholderRegion
= Placeholder
<BoundRegion
>;
1570 pub type PlaceholderType
= Placeholder
<BoundVar
>;
1572 pub type PlaceholderConst
= Placeholder
<BoundVar
>;
1574 /// When type checking, we use the `ParamEnv` to track
1575 /// details about the set of where-clauses that are in scope at this
1576 /// particular point.
1577 #[derive(Copy, Clone)]
1578 pub struct ParamEnv
<'tcx
> {
1579 // We pack the caller_bounds List pointer and a Reveal enum into this usize.
1580 // Specifically, the low bit represents Reveal, with 0 meaning `UserFacing`
1581 // and 1 meaning `All`. The rest is the pointer.
1583 // This relies on the List<ty::Predicate<'tcx>> type having at least 2-byte
1584 // alignment. Lists start with a usize and are repr(C) so this should be
1585 // fine; there is a debug_assert in the constructor as well.
1587 // Note that the choice of 0 for UserFacing is intentional -- since it is the
1588 // first variant in Reveal this means that joining the pointer is a simple `or`.
1591 /// `Obligation`s that the caller must satisfy. This is basically
1592 /// the set of bounds on the in-scope type parameters, translated
1593 /// into `Obligation`s, and elaborated and normalized.
1595 /// Note: This is packed into the `packed_data` usize above, use the
1596 /// `caller_bounds()` method to access it.
1597 caller_bounds
: PhantomData
<&'tcx List
<ty
::Predicate
<'tcx
>>>,
1599 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1600 /// want `Reveal::All`.
1602 /// Note: This is packed into the caller_bounds usize above, use the reveal()
1603 /// method to access it.
1604 reveal
: PhantomData
<traits
::Reveal
>,
1606 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1607 /// register that `def_id` (useful for transitioning to the chalk trait
1609 pub def_id
: Option
<DefId
>,
1612 impl<'tcx
> fmt
::Debug
for ParamEnv
<'tcx
> {
1613 fn fmt(&self, f
: &mut fmt
::Formatter
<'_
>) -> fmt
::Result
{
1614 f
.debug_struct("ParamEnv")
1615 .field("caller_bounds", &self.caller_bounds())
1616 .field("reveal", &self.reveal())
1617 .field("def_id", &self.def_id
)
1622 impl<'tcx
> Hash
for ParamEnv
<'tcx
> {
1623 fn hash
<H
: Hasher
>(&self, state
: &mut H
) {
1624 // List hashes as the raw pointer, so we can skip splitting into the
1625 // pointer and the enum.
1626 self.packed_data
.hash(state
);
1627 self.def_id
.hash(state
);
1631 impl<'tcx
> PartialEq
for ParamEnv
<'tcx
> {
1632 fn eq(&self, other
: &Self) -> bool
{
1633 self.caller_bounds() == other
.caller_bounds()
1634 && self.reveal() == other
.reveal()
1635 && self.def_id
== other
.def_id
1638 impl<'tcx
> Eq
for ParamEnv
<'tcx
> {}
1640 impl<'a
, 'tcx
> HashStable
<StableHashingContext
<'a
>> for ParamEnv
<'tcx
> {
1641 fn hash_stable(&self, hcx
: &mut StableHashingContext
<'a
>, hasher
: &mut StableHasher
) {
1642 self.caller_bounds().hash_stable(hcx
, hasher
);
1643 self.reveal().hash_stable(hcx
, hasher
);
1644 self.def_id
.hash_stable(hcx
, hasher
);
1648 impl<'tcx
> TypeFoldable
<'tcx
> for ParamEnv
<'tcx
> {
1649 fn super_fold_with
<F
: ty
::fold
::TypeFolder
<'tcx
>>(&self, folder
: &mut F
) -> Self {
1651 self.caller_bounds().fold_with(folder
),
1652 self.reveal().fold_with(folder
),
1653 self.def_id
.fold_with(folder
),
1657 fn super_visit_with
<V
: TypeVisitor
<'tcx
>>(&self, visitor
: &mut V
) -> bool
{
1658 self.caller_bounds().visit_with(visitor
)
1659 || self.reveal().visit_with(visitor
)
1660 || self.def_id
.visit_with(visitor
)
1664 impl<'tcx
> ParamEnv
<'tcx
> {
1665 /// Construct a trait environment suitable for contexts where
1666 /// there are no where-clauses in scope. Hidden types (like `impl
1667 /// Trait`) are left hidden, so this is suitable for ordinary
1670 pub fn empty() -> Self {
1671 Self::new(List
::empty(), Reveal
::UserFacing
, None
)
1675 pub fn caller_bounds(self) -> &'tcx List
<ty
::Predicate
<'tcx
>> {
1676 // mask out bottom bit
1677 unsafe { &*((self.packed_data & (!1)) as *const _) }
1681 pub fn reveal(self) -> traits
::Reveal
{
1682 if self.packed_data
& 1 == 0 { traits::Reveal::UserFacing }
else { traits::Reveal::All }
1685 /// Construct a trait environment with no where-clauses in scope
1686 /// where the values of all `impl Trait` and other hidden types
1687 /// are revealed. This is suitable for monomorphized, post-typeck
1688 /// environments like codegen or doing optimizations.
1690 /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
1691 /// or invoke `param_env.with_reveal_all()`.
1693 pub fn reveal_all() -> Self {
1694 Self::new(List
::empty(), Reveal
::All
, None
)
1697 /// Construct a trait environment with the given set of predicates.
1700 caller_bounds
: &'tcx List
<ty
::Predicate
<'tcx
>>,
1702 def_id
: Option
<DefId
>,
1704 let packed_data
= caller_bounds
as *const _
as usize;
1705 // Check that we can pack the reveal data into the pointer.
1706 debug_assert
!(packed_data
& 1 == 0);
1708 packed_data
: packed_data
1710 Reveal
::UserFacing
=> 0,
1713 caller_bounds
: PhantomData
,
1714 reveal
: PhantomData
,
1719 pub fn with_user_facing(mut self) -> Self {
1721 self.packed_data
&= !1;
1725 /// Returns a new parameter environment with the same clauses, but
1726 /// which "reveals" the true results of projections in all cases
1727 /// (even for associated types that are specializable). This is
1728 /// the desired behavior during codegen and certain other special
1729 /// contexts; normally though we want to use `Reveal::UserFacing`,
1730 /// which is the default.
1731 pub fn with_reveal_all(mut self) -> Self {
1732 self.packed_data
|= 1;
1736 /// Returns this same environment but with no caller bounds.
1737 pub fn without_caller_bounds(self) -> Self {
1738 Self::new(List
::empty(), self.reveal(), self.def_id
)
1741 /// Creates a suitable environment in which to perform trait
1742 /// queries on the given value. When type-checking, this is simply
1743 /// the pair of the environment plus value. But when reveal is set to
1744 /// All, then if `value` does not reference any type parameters, we will
1745 /// pair it with the empty environment. This improves caching and is generally
1748 /// N.B., we preserve the environment when type-checking because it
1749 /// is possible for the user to have wacky where-clauses like
1750 /// `where Box<u32>: Copy`, which are clearly never
1751 /// satisfiable. We generally want to behave as if they were true,
1752 /// although the surrounding function is never reachable.
1753 pub fn and
<T
: TypeFoldable
<'tcx
>>(self, value
: T
) -> ParamEnvAnd
<'tcx
, T
> {
1754 match self.reveal() {
1755 Reveal
::UserFacing
=> ParamEnvAnd { param_env: self, value }
,
1758 if value
.is_global() {
1759 ParamEnvAnd { param_env: self.without_caller_bounds(), value }
1761 ParamEnvAnd { param_env: self, value }
1768 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1769 pub struct ConstnessAnd
<T
> {
1770 pub constness
: Constness
,
1774 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
1775 // the constness of trait bounds is being propagated correctly.
1776 pub trait WithConstness
: Sized
{
1778 fn with_constness(self, constness
: Constness
) -> ConstnessAnd
<Self> {
1779 ConstnessAnd { constness, value: self }
1783 fn with_const(self) -> ConstnessAnd
<Self> {
1784 self.with_constness(Constness
::Const
)
1788 fn without_const(self) -> ConstnessAnd
<Self> {
1789 self.with_constness(Constness
::NotConst
)
1793 impl<T
> WithConstness
for T {}
1795 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
1796 pub struct ParamEnvAnd
<'tcx
, T
> {
1797 pub param_env
: ParamEnv
<'tcx
>,
1801 impl<'tcx
, T
> ParamEnvAnd
<'tcx
, T
> {
1802 pub fn into_parts(self) -> (ParamEnv
<'tcx
>, T
) {
1803 (self.param_env
, self.value
)
1807 impl<'a
, 'tcx
, T
> HashStable
<StableHashingContext
<'a
>> for ParamEnvAnd
<'tcx
, T
>
1809 T
: HashStable
<StableHashingContext
<'a
>>,
1811 fn hash_stable(&self, hcx
: &mut StableHashingContext
<'a
>, hasher
: &mut StableHasher
) {
1812 let ParamEnvAnd { ref param_env, ref value }
= *self;
1814 param_env
.hash_stable(hcx
, hasher
);
1815 value
.hash_stable(hcx
, hasher
);
1819 #[derive(Copy, Clone, Debug, HashStable)]
1820 pub struct Destructor
{
1821 /// The `DefId` of the destructor method
1826 #[derive(HashStable)]
1827 pub struct AdtFlags
: u32 {
1828 const NO_ADT_FLAGS
= 0;
1829 /// Indicates whether the ADT is an enum.
1830 const IS_ENUM
= 1 << 0;
1831 /// Indicates whether the ADT is a union.
1832 const IS_UNION
= 1 << 1;
1833 /// Indicates whether the ADT is a struct.
1834 const IS_STRUCT
= 1 << 2;
1835 /// Indicates whether the ADT is a struct and has a constructor.
1836 const HAS_CTOR
= 1 << 3;
1837 /// Indicates whether the type is `PhantomData`.
1838 const IS_PHANTOM_DATA
= 1 << 4;
1839 /// Indicates whether the type has a `#[fundamental]` attribute.
1840 const IS_FUNDAMENTAL
= 1 << 5;
1841 /// Indicates whether the type is `Box`.
1842 const IS_BOX
= 1 << 6;
1843 /// Indicates whether the type is `ManuallyDrop`.
1844 const IS_MANUALLY_DROP
= 1 << 7;
1845 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1846 /// (i.e., this flag is never set unless this ADT is an enum).
1847 const IS_VARIANT_LIST_NON_EXHAUSTIVE
= 1 << 8;
1852 #[derive(HashStable)]
1853 pub struct VariantFlags
: u32 {
1854 const NO_VARIANT_FLAGS
= 0;
1855 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1856 const IS_FIELD_LIST_NON_EXHAUSTIVE
= 1 << 0;
1860 /// Definition of a variant -- a struct's fields or a enum variant.
1861 #[derive(Debug, HashStable)]
1862 pub struct VariantDef
{
1863 /// `DefId` that identifies the variant itself.
1864 /// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
1866 /// `DefId` that identifies the variant's constructor.
1867 /// If this variant is a struct variant, then this is `None`.
1868 pub ctor_def_id
: Option
<DefId
>,
1869 /// Variant or struct name.
1870 #[stable_hasher(project(name))]
1872 /// Discriminant of this variant.
1873 pub discr
: VariantDiscr
,
1874 /// Fields of this variant.
1875 pub fields
: Vec
<FieldDef
>,
1876 /// Type of constructor of variant.
1877 pub ctor_kind
: CtorKind
,
1878 /// Flags of the variant (e.g. is field list non-exhaustive)?
1879 flags
: VariantFlags
,
1880 /// Variant is obtained as part of recovering from a syntactic error.
1881 /// May be incomplete or bogus.
1882 pub recovered
: bool
,
1885 impl<'tcx
> VariantDef
{
1886 /// Creates a new `VariantDef`.
1888 /// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
1889 /// represents an enum variant).
1891 /// `ctor_did` is the `DefId` that identifies the constructor of unit or
1892 /// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
1894 /// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
1895 /// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
1896 /// to go through the redirect of checking the ctor's attributes - but compiling a small crate
1897 /// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
1898 /// built-in trait), and we do not want to load attributes twice.
1900 /// If someone speeds up attribute loading to not be a performance concern, they can
1901 /// remove this hack and use the constructor `DefId` everywhere.
1905 variant_did
: Option
<DefId
>,
1906 ctor_def_id
: Option
<DefId
>,
1907 discr
: VariantDiscr
,
1908 fields
: Vec
<FieldDef
>,
1909 ctor_kind
: CtorKind
,
1915 "VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
1916 fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
1917 ident
, variant_did
, ctor_def_id
, discr
, fields
, ctor_kind
, adt_kind
, parent_did
,
1920 let mut flags
= VariantFlags
::NO_VARIANT_FLAGS
;
1921 if adt_kind
== AdtKind
::Struct
&& tcx
.has_attr(parent_did
, sym
::non_exhaustive
) {
1922 debug
!("found non-exhaustive field list for {:?}", parent_did
);
1923 flags
= flags
| VariantFlags
::IS_FIELD_LIST_NON_EXHAUSTIVE
;
1924 } else if let Some(variant_did
) = variant_did
{
1925 if tcx
.has_attr(variant_did
, sym
::non_exhaustive
) {
1926 debug
!("found non-exhaustive field list for {:?}", variant_did
);
1927 flags
= flags
| VariantFlags
::IS_FIELD_LIST_NON_EXHAUSTIVE
;
1932 def_id
: variant_did
.unwrap_or(parent_did
),
1943 /// Is this field list non-exhaustive?
1945 pub fn is_field_list_non_exhaustive(&self) -> bool
{
1946 self.flags
.intersects(VariantFlags
::IS_FIELD_LIST_NON_EXHAUSTIVE
)
1949 /// `repr(transparent)` structs can have a single non-ZST field, this function returns that
1951 pub fn transparent_newtype_field(&self, tcx
: TyCtxt
<'tcx
>) -> Option
<&FieldDef
> {
1952 for field
in &self.fields
{
1953 let field_ty
= field
.ty(tcx
, InternalSubsts
::identity_for_item(tcx
, self.def_id
));
1954 if !field_ty
.is_zst(tcx
, self.def_id
) {
1963 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
1964 pub enum VariantDiscr
{
1965 /// Explicit value for this variant, i.e., `X = 123`.
1966 /// The `DefId` corresponds to the embedded constant.
1969 /// The previous variant's discriminant plus one.
1970 /// For efficiency reasons, the distance from the
1971 /// last `Explicit` discriminant is being stored,
1972 /// or `0` for the first variant, if it has none.
1976 #[derive(Debug, HashStable)]
1977 pub struct FieldDef
{
1979 #[stable_hasher(project(name))]
1981 pub vis
: Visibility
,
1984 /// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
1986 /// These are all interned (by `alloc_adt_def`) into the global arena.
1988 /// The initialism *ADT* stands for an [*algebraic data type (ADT)*][adt].
1989 /// This is slightly wrong because `union`s are not ADTs.
1990 /// Moreover, Rust only allows recursive data types through indirection.
1992 /// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
1994 /// The `DefId` of the struct, enum or union item.
1996 /// Variants of the ADT. If this is a struct or union, then there will be a single variant.
1997 pub variants
: IndexVec
<VariantIdx
, VariantDef
>,
1998 /// Flags of the ADT (e.g., is this a struct? is this non-exhaustive?).
2000 /// Repr options provided by the user.
2001 pub repr
: ReprOptions
,
2004 impl PartialOrd
for AdtDef
{
2005 fn partial_cmp(&self, other
: &AdtDef
) -> Option
<Ordering
> {
2006 Some(self.cmp(&other
))
2010 /// There should be only one AdtDef for each `did`, therefore
2011 /// it is fine to implement `Ord` only based on `did`.
2012 impl Ord
for AdtDef
{
2013 fn cmp(&self, other
: &AdtDef
) -> Ordering
{
2014 self.did
.cmp(&other
.did
)
2018 impl PartialEq
for AdtDef
{
2019 // `AdtDef`s are always interned, and this is part of `TyS` equality.
2021 fn eq(&self, other
: &Self) -> bool
{
2022 ptr
::eq(self, other
)
2026 impl Eq
for AdtDef {}
2028 impl Hash
for AdtDef
{
2030 fn hash
<H
: Hasher
>(&self, s
: &mut H
) {
2031 (self as *const AdtDef
).hash(s
)
2035 impl<'tcx
> rustc_serialize
::UseSpecializedEncodable
for &'tcx AdtDef
{
2036 fn default_encode
<S
: Encoder
>(&self, s
: &mut S
) -> Result
<(), S
::Error
> {
2041 impl<'tcx
> rustc_serialize
::UseSpecializedDecodable
for &'tcx AdtDef {}
2043 impl<'a
> HashStable
<StableHashingContext
<'a
>> for AdtDef
{
2044 fn hash_stable(&self, hcx
: &mut StableHashingContext
<'a
>, hasher
: &mut StableHasher
) {
2046 static CACHE
: RefCell
<FxHashMap
<usize, Fingerprint
>> = Default
::default();
2049 let hash
: Fingerprint
= CACHE
.with(|cache
| {
2050 let addr
= self as *const AdtDef
as usize;
2051 *cache
.borrow_mut().entry(addr
).or_insert_with(|| {
2052 let ty
::AdtDef { did, ref variants, ref flags, ref repr }
= *self;
2054 let mut hasher
= StableHasher
::new();
2055 did
.hash_stable(hcx
, &mut hasher
);
2056 variants
.hash_stable(hcx
, &mut hasher
);
2057 flags
.hash_stable(hcx
, &mut hasher
);
2058 repr
.hash_stable(hcx
, &mut hasher
);
2064 hash
.hash_stable(hcx
, hasher
);
2068 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
2075 impl Into
<DataTypeKind
> for AdtKind
{
2076 fn into(self) -> DataTypeKind
{
2078 AdtKind
::Struct
=> DataTypeKind
::Struct
,
2079 AdtKind
::Union
=> DataTypeKind
::Union
,
2080 AdtKind
::Enum
=> DataTypeKind
::Enum
,
2086 #[derive(RustcEncodable, RustcDecodable, Default, HashStable)]
2087 pub struct ReprFlags
: u8 {
2088 const IS_C
= 1 << 0;
2089 const IS_SIMD
= 1 << 1;
2090 const IS_TRANSPARENT
= 1 << 2;
2091 // Internal only for now. If true, don't reorder fields.
2092 const IS_LINEAR
= 1 << 3;
2093 // If true, don't expose any niche to type's context.
2094 const HIDE_NICHE
= 1 << 4;
2095 // Any of these flags being set prevent field reordering optimisation.
2096 const IS_UNOPTIMISABLE
= ReprFlags
::IS_C
.bits
|
2097 ReprFlags
::IS_SIMD
.bits
|
2098 ReprFlags
::IS_LINEAR
.bits
;
2102 /// Represents the repr options provided by the user,
2103 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default, HashStable)]
2104 pub struct ReprOptions
{
2105 pub int
: Option
<attr
::IntType
>,
2106 pub align
: Option
<Align
>,
2107 pub pack
: Option
<Align
>,
2108 pub flags
: ReprFlags
,
2112 pub fn new(tcx
: TyCtxt
<'_
>, did
: DefId
) -> ReprOptions
{
2113 let mut flags
= ReprFlags
::empty();
2114 let mut size
= None
;
2115 let mut max_align
: Option
<Align
> = None
;
2116 let mut min_pack
: Option
<Align
> = None
;
2117 for attr
in tcx
.get_attrs(did
).iter() {
2118 for r
in attr
::find_repr_attrs(&tcx
.sess
.parse_sess
, attr
) {
2119 flags
.insert(match r
{
2120 attr
::ReprC
=> ReprFlags
::IS_C
,
2121 attr
::ReprPacked(pack
) => {
2122 let pack
= Align
::from_bytes(pack
as u64).unwrap();
2123 min_pack
= Some(if let Some(min_pack
) = min_pack
{
2130 attr
::ReprTransparent
=> ReprFlags
::IS_TRANSPARENT
,
2131 attr
::ReprNoNiche
=> ReprFlags
::HIDE_NICHE
,
2132 attr
::ReprSimd
=> ReprFlags
::IS_SIMD
,
2133 attr
::ReprInt(i
) => {
2137 attr
::ReprAlign(align
) => {
2138 max_align
= max_align
.max(Some(Align
::from_bytes(align
as u64).unwrap()));
2145 // This is here instead of layout because the choice must make it into metadata.
2146 if !tcx
.consider_optimizing(|| format
!("Reorder fields of {:?}", tcx
.def_path_str(did
))) {
2147 flags
.insert(ReprFlags
::IS_LINEAR
);
2149 ReprOptions { int: size, align: max_align, pack: min_pack, flags }
2153 pub fn simd(&self) -> bool
{
2154 self.flags
.contains(ReprFlags
::IS_SIMD
)
2157 pub fn c(&self) -> bool
{
2158 self.flags
.contains(ReprFlags
::IS_C
)
2161 pub fn packed(&self) -> bool
{
2165 pub fn transparent(&self) -> bool
{
2166 self.flags
.contains(ReprFlags
::IS_TRANSPARENT
)
2169 pub fn linear(&self) -> bool
{
2170 self.flags
.contains(ReprFlags
::IS_LINEAR
)
2173 pub fn hide_niche(&self) -> bool
{
2174 self.flags
.contains(ReprFlags
::HIDE_NICHE
)
2177 /// Returns the discriminant type, given these `repr` options.
2178 /// This must only be called on enums!
2179 pub fn discr_type(&self) -> attr
::IntType
{
2180 self.int
.unwrap_or(attr
::SignedInt(ast
::IntTy
::Isize
))
2183 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2184 /// layout" optimizations, such as representing `Foo<&T>` as a
2186 pub fn inhibit_enum_layout_opt(&self) -> bool
{
2187 self.c() || self.int
.is_some()
2190 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2191 /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
2192 pub fn inhibit_struct_field_reordering_opt(&self) -> bool
{
2193 if let Some(pack
) = self.pack
{
2194 if pack
.bytes() == 1 {
2198 self.flags
.intersects(ReprFlags
::IS_UNOPTIMISABLE
) || self.int
.is_some()
2201 /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
2202 pub fn inhibit_union_abi_opt(&self) -> bool
{
2208 /// Creates a new `AdtDef`.
2213 variants
: IndexVec
<VariantIdx
, VariantDef
>,
2216 debug
!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did
, kind
, variants
, repr
);
2217 let mut flags
= AdtFlags
::NO_ADT_FLAGS
;
2219 if kind
== AdtKind
::Enum
&& tcx
.has_attr(did
, sym
::non_exhaustive
) {
2220 debug
!("found non-exhaustive variant list for {:?}", did
);
2221 flags
= flags
| AdtFlags
::IS_VARIANT_LIST_NON_EXHAUSTIVE
;
2224 flags
|= match kind
{
2225 AdtKind
::Enum
=> AdtFlags
::IS_ENUM
,
2226 AdtKind
::Union
=> AdtFlags
::IS_UNION
,
2227 AdtKind
::Struct
=> AdtFlags
::IS_STRUCT
,
2230 if kind
== AdtKind
::Struct
&& variants
[VariantIdx
::new(0)].ctor_def_id
.is_some() {
2231 flags
|= AdtFlags
::HAS_CTOR
;
2234 let attrs
= tcx
.get_attrs(did
);
2235 if attr
::contains_name(&attrs
, sym
::fundamental
) {
2236 flags
|= AdtFlags
::IS_FUNDAMENTAL
;
2238 if Some(did
) == tcx
.lang_items().phantom_data() {
2239 flags
|= AdtFlags
::IS_PHANTOM_DATA
;
2241 if Some(did
) == tcx
.lang_items().owned_box() {
2242 flags
|= AdtFlags
::IS_BOX
;
2244 if Some(did
) == tcx
.lang_items().manually_drop() {
2245 flags
|= AdtFlags
::IS_MANUALLY_DROP
;
2248 AdtDef { did, variants, flags, repr }
2251 /// Returns `true` if this is a struct.
2253 pub fn is_struct(&self) -> bool
{
2254 self.flags
.contains(AdtFlags
::IS_STRUCT
)
2257 /// Returns `true` if this is a union.
2259 pub fn is_union(&self) -> bool
{
2260 self.flags
.contains(AdtFlags
::IS_UNION
)
2263 /// Returns `true` if this is a enum.
2265 pub fn is_enum(&self) -> bool
{
2266 self.flags
.contains(AdtFlags
::IS_ENUM
)
2269 /// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
2271 pub fn is_variant_list_non_exhaustive(&self) -> bool
{
2272 self.flags
.contains(AdtFlags
::IS_VARIANT_LIST_NON_EXHAUSTIVE
)
2275 /// Returns the kind of the ADT.
2277 pub fn adt_kind(&self) -> AdtKind
{
2280 } else if self.is_union() {
2287 /// Returns a description of this abstract data type.
2288 pub fn descr(&self) -> &'
static str {
2289 match self.adt_kind() {
2290 AdtKind
::Struct
=> "struct",
2291 AdtKind
::Union
=> "union",
2292 AdtKind
::Enum
=> "enum",
2296 /// Returns a description of a variant of this abstract data type.
2298 pub fn variant_descr(&self) -> &'
static str {
2299 match self.adt_kind() {
2300 AdtKind
::Struct
=> "struct",
2301 AdtKind
::Union
=> "union",
2302 AdtKind
::Enum
=> "variant",
2306 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2308 pub fn has_ctor(&self) -> bool
{
2309 self.flags
.contains(AdtFlags
::HAS_CTOR
)
2312 /// Returns `true` if this type is `#[fundamental]` for the purposes
2313 /// of coherence checking.
2315 pub fn is_fundamental(&self) -> bool
{
2316 self.flags
.contains(AdtFlags
::IS_FUNDAMENTAL
)
2319 /// Returns `true` if this is `PhantomData<T>`.
2321 pub fn is_phantom_data(&self) -> bool
{
2322 self.flags
.contains(AdtFlags
::IS_PHANTOM_DATA
)
2325 /// Returns `true` if this is Box<T>.
2327 pub fn is_box(&self) -> bool
{
2328 self.flags
.contains(AdtFlags
::IS_BOX
)
2331 /// Returns `true` if this is `ManuallyDrop<T>`.
2333 pub fn is_manually_drop(&self) -> bool
{
2334 self.flags
.contains(AdtFlags
::IS_MANUALLY_DROP
)
2337 /// Returns `true` if this type has a destructor.
2338 pub fn has_dtor(&self, tcx
: TyCtxt
<'tcx
>) -> bool
{
2339 self.destructor(tcx
).is_some()
2342 /// Asserts this is a struct or union and returns its unique variant.
2343 pub fn non_enum_variant(&self) -> &VariantDef
{
2344 assert
!(self.is_struct() || self.is_union());
2345 &self.variants
[VariantIdx
::new(0)]
2349 pub fn predicates(&self, tcx
: TyCtxt
<'tcx
>) -> GenericPredicates
<'tcx
> {
2350 tcx
.predicates_of(self.did
)
2353 /// Returns an iterator over all fields contained
2356 pub fn all_fields(&self) -> impl Iterator
<Item
= &FieldDef
> + Clone
{
2357 self.variants
.iter().flat_map(|v
| v
.fields
.iter())
2360 pub fn is_payloadfree(&self) -> bool
{
2361 !self.variants
.is_empty() && self.variants
.iter().all(|v
| v
.fields
.is_empty())
2364 /// Return a `VariantDef` given a variant id.
2365 pub fn variant_with_id(&self, vid
: DefId
) -> &VariantDef
{
2366 self.variants
.iter().find(|v
| v
.def_id
== vid
).expect("variant_with_id: unknown variant")
2369 /// Return a `VariantDef` given a constructor id.
2370 pub fn variant_with_ctor_id(&self, cid
: DefId
) -> &VariantDef
{
2373 .find(|v
| v
.ctor_def_id
== Some(cid
))
2374 .expect("variant_with_ctor_id: unknown variant")
2377 /// Return the index of `VariantDef` given a variant id.
2378 pub fn variant_index_with_id(&self, vid
: DefId
) -> VariantIdx
{
2381 .find(|(_
, v
)| v
.def_id
== vid
)
2382 .expect("variant_index_with_id: unknown variant")
2386 /// Return the index of `VariantDef` given a constructor id.
2387 pub fn variant_index_with_ctor_id(&self, cid
: DefId
) -> VariantIdx
{
2390 .find(|(_
, v
)| v
.ctor_def_id
== Some(cid
))
2391 .expect("variant_index_with_ctor_id: unknown variant")
2395 pub fn variant_of_res(&self, res
: Res
) -> &VariantDef
{
2397 Res
::Def(DefKind
::Variant
, vid
) => self.variant_with_id(vid
),
2398 Res
::Def(DefKind
::Ctor(..), cid
) => self.variant_with_ctor_id(cid
),
2399 Res
::Def(DefKind
::Struct
, _
)
2400 | Res
::Def(DefKind
::Union
, _
)
2401 | Res
::Def(DefKind
::TyAlias
, _
)
2402 | Res
::Def(DefKind
::AssocTy
, _
)
2404 | Res
::SelfCtor(..) => self.non_enum_variant(),
2405 _
=> bug
!("unexpected res {:?} in variant_of_res", res
),
2410 pub fn eval_explicit_discr(&self, tcx
: TyCtxt
<'tcx
>, expr_did
: DefId
) -> Option
<Discr
<'tcx
>> {
2411 assert
!(self.is_enum());
2412 let param_env
= tcx
.param_env(expr_did
);
2413 let repr_type
= self.repr
.discr_type();
2414 match tcx
.const_eval_poly(expr_did
) {
2416 let ty
= repr_type
.to_ty(tcx
);
2417 if let Some(b
) = val
.try_to_bits_for_ty(tcx
, param_env
, ty
) {
2418 trace
!("discriminants: {} ({:?})", b
, repr_type
);
2419 Some(Discr { val: b, ty }
)
2421 info
!("invalid enum discriminant: {:#?}", val
);
2422 crate::mir
::interpret
::struct_error(
2423 tcx
.at(tcx
.def_span(expr_did
)),
2424 "constant evaluation of enum discriminant resulted in non-integer",
2431 let msg
= match err
{
2432 ErrorHandled
::Reported(ErrorReported
) | ErrorHandled
::Linted
=> {
2433 "enum discriminant evaluation failed"
2435 ErrorHandled
::TooGeneric
=> "enum discriminant depends on generics",
2437 tcx
.sess
.delay_span_bug(tcx
.def_span(expr_did
), msg
);
2444 pub fn discriminants(
2447 ) -> impl Iterator
<Item
= (VariantIdx
, Discr
<'tcx
>)> + Captures
<'tcx
> {
2448 assert
!(self.is_enum());
2449 let repr_type
= self.repr
.discr_type();
2450 let initial
= repr_type
.initial_discriminant(tcx
);
2451 let mut prev_discr
= None
::<Discr
<'tcx
>>;
2452 self.variants
.iter_enumerated().map(move |(i
, v
)| {
2453 let mut discr
= prev_discr
.map_or(initial
, |d
| d
.wrap_incr(tcx
));
2454 if let VariantDiscr
::Explicit(expr_did
) = v
.discr
{
2455 if let Some(new_discr
) = self.eval_explicit_discr(tcx
, expr_did
) {
2459 prev_discr
= Some(discr
);
2466 pub fn variant_range(&self) -> Range
<VariantIdx
> {
2467 VariantIdx
::new(0)..VariantIdx
::new(self.variants
.len())
2470 /// Computes the discriminant value used by a specific variant.
2471 /// Unlike `discriminants`, this is (amortized) constant-time,
2472 /// only doing at most one query for evaluating an explicit
2473 /// discriminant (the last one before the requested variant),
2474 /// assuming there are no constant-evaluation errors there.
2476 pub fn discriminant_for_variant(
2479 variant_index
: VariantIdx
,
2481 assert
!(self.is_enum());
2482 let (val
, offset
) = self.discriminant_def_for_variant(variant_index
);
2483 let explicit_value
= val
2484 .and_then(|expr_did
| self.eval_explicit_discr(tcx
, expr_did
))
2485 .unwrap_or_else(|| self.repr
.discr_type().initial_discriminant(tcx
));
2486 explicit_value
.checked_add(tcx
, offset
as u128
).0
2489 /// Yields a `DefId` for the discriminant and an offset to add to it
2490 /// Alternatively, if there is no explicit discriminant, returns the
2491 /// inferred discriminant directly.
2492 pub fn discriminant_def_for_variant(&self, variant_index
: VariantIdx
) -> (Option
<DefId
>, u32) {
2493 assert
!(!self.variants
.is_empty());
2494 let mut explicit_index
= variant_index
.as_u32();
2497 match self.variants
[VariantIdx
::from_u32(explicit_index
)].discr
{
2498 ty
::VariantDiscr
::Relative(0) => {
2502 ty
::VariantDiscr
::Relative(distance
) => {
2503 explicit_index
-= distance
;
2505 ty
::VariantDiscr
::Explicit(did
) => {
2506 expr_did
= Some(did
);
2511 (expr_did
, variant_index
.as_u32() - explicit_index
)
2514 pub fn destructor(&self, tcx
: TyCtxt
<'tcx
>) -> Option
<Destructor
> {
2515 tcx
.adt_destructor(self.did
)
2518 /// Returns a list of types such that `Self: Sized` if and only
2519 /// if that type is `Sized`, or `TyErr` if this type is recursive.
2521 /// Oddly enough, checking that the sized-constraint is `Sized` is
2522 /// actually more expressive than checking all members:
2523 /// the `Sized` trait is inductive, so an associated type that references
2524 /// `Self` would prevent its containing ADT from being `Sized`.
2526 /// Due to normalization being eager, this applies even if
2527 /// the associated type is behind a pointer (e.g., issue #31299).
2528 pub fn sized_constraint(&self, tcx
: TyCtxt
<'tcx
>) -> &'tcx
[Ty
<'tcx
>] {
2529 tcx
.adt_sized_constraint(self.did
).0
2533 impl<'tcx
> FieldDef
{
2534 /// Returns the type of this field. The `subst` is typically obtained
2535 /// via the second field of `TyKind::AdtDef`.
2536 pub fn ty(&self, tcx
: TyCtxt
<'tcx
>, subst
: SubstsRef
<'tcx
>) -> Ty
<'tcx
> {
2537 tcx
.type_of(self.did
).subst(tcx
, subst
)
2541 /// Represents the various closure traits in the language. This
2542 /// will determine the type of the environment (`self`, in the
2543 /// desugaring) argument that the closure expects.
2545 /// You can get the environment type of a closure using
2546 /// `tcx.closure_env_ty()`.
2547 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2548 #[derive(HashStable)]
2549 pub enum ClosureKind
{
2550 // Warning: Ordering is significant here! The ordering is chosen
2551 // because the trait Fn is a subtrait of FnMut and so in turn, and
2552 // hence we order it so that Fn < FnMut < FnOnce.
2558 impl<'tcx
> ClosureKind
{
2559 // This is the initial value used when doing upvar inference.
2560 pub const LATTICE_BOTTOM
: ClosureKind
= ClosureKind
::Fn
;
2562 pub fn trait_did(&self, tcx
: TyCtxt
<'tcx
>) -> DefId
{
2564 ClosureKind
::Fn
=> tcx
.require_lang_item(FnTraitLangItem
, None
),
2565 ClosureKind
::FnMut
=> tcx
.require_lang_item(FnMutTraitLangItem
, None
),
2566 ClosureKind
::FnOnce
=> tcx
.require_lang_item(FnOnceTraitLangItem
, None
),
2570 /// Returns `true` if this a type that impls this closure kind
2571 /// must also implement `other`.
2572 pub fn extends(self, other
: ty
::ClosureKind
) -> bool
{
2573 match (self, other
) {
2574 (ClosureKind
::Fn
, ClosureKind
::Fn
) => true,
2575 (ClosureKind
::Fn
, ClosureKind
::FnMut
) => true,
2576 (ClosureKind
::Fn
, ClosureKind
::FnOnce
) => true,
2577 (ClosureKind
::FnMut
, ClosureKind
::FnMut
) => true,
2578 (ClosureKind
::FnMut
, ClosureKind
::FnOnce
) => true,
2579 (ClosureKind
::FnOnce
, ClosureKind
::FnOnce
) => true,
2584 /// Returns the representative scalar type for this closure kind.
2585 /// See `TyS::to_opt_closure_kind` for more details.
2586 pub fn to_ty(self, tcx
: TyCtxt
<'tcx
>) -> Ty
<'tcx
> {
2588 ty
::ClosureKind
::Fn
=> tcx
.types
.i8,
2589 ty
::ClosureKind
::FnMut
=> tcx
.types
.i16,
2590 ty
::ClosureKind
::FnOnce
=> tcx
.types
.i32,
2596 pub fn from_mutbl(m
: hir
::Mutability
) -> BorrowKind
{
2598 hir
::Mutability
::Mut
=> MutBorrow
,
2599 hir
::Mutability
::Not
=> ImmBorrow
,
2603 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2604 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2605 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2607 pub fn to_mutbl_lossy(self) -> hir
::Mutability
{
2609 MutBorrow
=> hir
::Mutability
::Mut
,
2610 ImmBorrow
=> hir
::Mutability
::Not
,
2612 // We have no type corresponding to a unique imm borrow, so
2613 // use `&mut`. It gives all the capabilities of an `&uniq`
2614 // and hence is a safe "over approximation".
2615 UniqueImmBorrow
=> hir
::Mutability
::Mut
,
2619 pub fn to_user_str(&self) -> &'
static str {
2621 MutBorrow
=> "mutable",
2622 ImmBorrow
=> "immutable",
2623 UniqueImmBorrow
=> "uniquely immutable",
2628 pub type Attributes
<'tcx
> = &'tcx
[ast
::Attribute
];
2630 #[derive(Debug, PartialEq, Eq)]
2631 pub enum ImplOverlapKind
{
2632 /// These impls are always allowed to overlap.
2634 /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
2637 /// These impls are allowed to overlap, but that raises
2638 /// an issue #33140 future-compatibility warning.
2640 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2641 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2643 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2644 /// that difference, making what reduces to the following set of impls:
2648 /// impl Trait for dyn Send + Sync {}
2649 /// impl Trait for dyn Sync + Send {}
2652 /// Obviously, once we made these types be identical, that code causes a coherence
2653 /// error and a fairly big headache for us. However, luckily for us, the trait
2654 /// `Trait` used in this case is basically a marker trait, and therefore having
2655 /// overlapping impls for it is sound.
2657 /// To handle this, we basically regard the trait as a marker trait, with an additional
2658 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2659 /// it has the following restrictions:
2661 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2663 /// 2. The trait-ref of both impls must be equal.
2664 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2666 /// 4. Neither of the impls can have any where-clauses.
2668 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2672 impl<'tcx
> TyCtxt
<'tcx
> {
2673 pub fn body_tables(self, body
: hir
::BodyId
) -> &'tcx TypeckTables
<'tcx
> {
2674 self.typeck_tables_of(self.hir().body_owner_def_id(body
))
2677 /// Returns an iterator of the `DefId`s for all body-owners in this
2678 /// crate. If you would prefer to iterate over the bodies
2679 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2680 pub fn body_owners(self) -> impl Iterator
<Item
= LocalDefId
> + Captures
<'tcx
> + 'tcx
{
2685 .map(move |&body_id
| self.hir().body_owner_def_id(body_id
))
2688 pub fn par_body_owners
<F
: Fn(LocalDefId
) + sync
::Sync
+ sync
::Send
>(self, f
: F
) {
2689 par_iter(&self.hir().krate().body_ids
)
2690 .for_each(|&body_id
| f(self.hir().body_owner_def_id(body_id
)));
2693 pub fn provided_trait_methods(self, id
: DefId
) -> impl 'tcx
+ Iterator
<Item
= &'tcx AssocItem
> {
2694 self.associated_items(id
)
2695 .in_definition_order()
2696 .filter(|item
| item
.kind
== AssocKind
::Fn
&& item
.defaultness
.has_value())
2699 pub fn opt_item_name(self, def_id
: DefId
) -> Option
<Ident
> {
2702 .and_then(|def_id
| self.hir().get(self.hir().as_local_hir_id(def_id
)).ident())
2705 pub fn opt_associated_item(self, def_id
: DefId
) -> Option
<&'tcx AssocItem
> {
2706 let is_associated_item
= if let Some(def_id
) = def_id
.as_local() {
2707 match self.hir().get(self.hir().as_local_hir_id(def_id
)) {
2708 Node
::TraitItem(_
) | Node
::ImplItem(_
) => true,
2712 match self.def_kind(def_id
) {
2713 DefKind
::AssocConst
| DefKind
::AssocFn
| DefKind
::AssocTy
=> true,
2718 is_associated_item
.then(|| self.associated_item(def_id
))
2721 pub fn field_index(self, hir_id
: hir
::HirId
, tables
: &TypeckTables
<'_
>) -> usize {
2722 tables
.field_indices().get(hir_id
).cloned().expect("no index for a field")
2725 pub fn find_field_index(self, ident
: Ident
, variant
: &VariantDef
) -> Option
<usize> {
2726 variant
.fields
.iter().position(|field
| self.hygienic_eq(ident
, field
.ident
, variant
.def_id
))
2729 /// Returns `true` if the impls are the same polarity and the trait either
2730 /// has no items or is annotated `#[marker]` and prevents item overrides.
2731 pub fn impls_are_allowed_to_overlap(
2735 ) -> Option
<ImplOverlapKind
> {
2736 // If either trait impl references an error, they're allowed to overlap,
2737 // as one of them essentially doesn't exist.
2738 if self.impl_trait_ref(def_id1
).map_or(false, |tr
| tr
.references_error())
2739 || self.impl_trait_ref(def_id2
).map_or(false, |tr
| tr
.references_error())
2741 return Some(ImplOverlapKind
::Permitted { marker: false }
);
2744 match (self.impl_polarity(def_id1
), self.impl_polarity(def_id2
)) {
2745 (ImplPolarity
::Reservation
, _
) | (_
, ImplPolarity
::Reservation
) => {
2746 // `#[rustc_reservation_impl]` impls don't overlap with anything
2748 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
2751 return Some(ImplOverlapKind
::Permitted { marker: false }
);
2753 (ImplPolarity
::Positive
, ImplPolarity
::Negative
)
2754 | (ImplPolarity
::Negative
, ImplPolarity
::Positive
) => {
2755 // `impl AutoTrait for Type` + `impl !AutoTrait for Type`
2757 "impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
2762 (ImplPolarity
::Positive
, ImplPolarity
::Positive
)
2763 | (ImplPolarity
::Negative
, ImplPolarity
::Negative
) => {}
2766 let is_marker_overlap
= {
2767 let is_marker_impl
= |def_id
: DefId
| -> bool
{
2768 let trait_ref
= self.impl_trait_ref(def_id
);
2769 trait_ref
.map_or(false, |tr
| self.trait_def(tr
.def_id
).is_marker
)
2771 is_marker_impl(def_id1
) && is_marker_impl(def_id2
)
2774 if is_marker_overlap
{
2776 "impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
2779 Some(ImplOverlapKind
::Permitted { marker: true }
)
2781 if let Some(self_ty1
) = self.issue33140_self_ty(def_id1
) {
2782 if let Some(self_ty2
) = self.issue33140_self_ty(def_id2
) {
2783 if self_ty1
== self_ty2
{
2785 "impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2788 return Some(ImplOverlapKind
::Issue33140
);
2791 "impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2792 def_id1
, def_id2
, self_ty1
, self_ty2
2798 debug
!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1
, def_id2
);
2803 /// Returns `ty::VariantDef` if `res` refers to a struct,
2804 /// or variant or their constructors, panics otherwise.
2805 pub fn expect_variant_res(self, res
: Res
) -> &'tcx VariantDef
{
2807 Res
::Def(DefKind
::Variant
, did
) => {
2808 let enum_did
= self.parent(did
).unwrap();
2809 self.adt_def(enum_did
).variant_with_id(did
)
2811 Res
::Def(DefKind
::Struct
| DefKind
::Union
, did
) => self.adt_def(did
).non_enum_variant(),
2812 Res
::Def(DefKind
::Ctor(CtorOf
::Variant
, ..), variant_ctor_did
) => {
2813 let variant_did
= self.parent(variant_ctor_did
).unwrap();
2814 let enum_did
= self.parent(variant_did
).unwrap();
2815 self.adt_def(enum_did
).variant_with_ctor_id(variant_ctor_did
)
2817 Res
::Def(DefKind
::Ctor(CtorOf
::Struct
, ..), ctor_did
) => {
2818 let struct_did
= self.parent(ctor_did
).expect("struct ctor has no parent");
2819 self.adt_def(struct_did
).non_enum_variant()
2821 _
=> bug
!("expect_variant_res used with unexpected res {:?}", res
),
2825 pub fn item_name(self, id
: DefId
) -> Symbol
{
2826 if id
.index
== CRATE_DEF_INDEX
{
2827 self.original_crate_name(id
.krate
)
2829 let def_key
= self.def_key(id
);
2830 match def_key
.disambiguated_data
.data
{
2831 // The name of a constructor is that of its parent.
2832 rustc_hir
::definitions
::DefPathData
::Ctor
=> {
2833 self.item_name(DefId { krate: id.krate, index: def_key.parent.unwrap() }
)
2835 _
=> def_key
.disambiguated_data
.data
.get_opt_name().unwrap_or_else(|| {
2836 bug
!("item_name: no name for {:?}", self.def_path(id
));
2842 /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
2843 pub fn instance_mir(self, instance
: ty
::InstanceDef
<'tcx
>) -> &'tcx Body
<'tcx
> {
2845 ty
::InstanceDef
::Item(did
) => self.optimized_mir(did
),
2846 ty
::InstanceDef
::VtableShim(..)
2847 | ty
::InstanceDef
::ReifyShim(..)
2848 | ty
::InstanceDef
::Intrinsic(..)
2849 | ty
::InstanceDef
::FnPtrShim(..)
2850 | ty
::InstanceDef
::Virtual(..)
2851 | ty
::InstanceDef
::ClosureOnceShim { .. }
2852 | ty
::InstanceDef
::DropGlue(..)
2853 | ty
::InstanceDef
::CloneShim(..) => self.mir_shims(instance
),
2857 /// Gets the attributes of a definition.
2858 pub fn get_attrs(self, did
: DefId
) -> Attributes
<'tcx
> {
2859 if let Some(did
) = did
.as_local() {
2860 self.hir().attrs(self.hir().as_local_hir_id(did
))
2862 self.item_attrs(did
)
2866 /// Determines whether an item is annotated with an attribute.
2867 pub fn has_attr(self, did
: DefId
, attr
: Symbol
) -> bool
{
2868 attr
::contains_name(&self.get_attrs(did
), attr
)
2871 /// Returns `true` if this is an `auto trait`.
2872 pub fn trait_is_auto(self, trait_def_id
: DefId
) -> bool
{
2873 self.trait_def(trait_def_id
).has_auto_impl
2876 pub fn generator_layout(self, def_id
: DefId
) -> &'tcx GeneratorLayout
<'tcx
> {
2877 self.optimized_mir(def_id
).generator_layout
.as_ref().unwrap()
2880 /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
2881 /// If it implements no trait, returns `None`.
2882 pub fn trait_id_of_impl(self, def_id
: DefId
) -> Option
<DefId
> {
2883 self.impl_trait_ref(def_id
).map(|tr
| tr
.def_id
)
2886 /// If the given defid describes a method belonging to an impl, returns the
2887 /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
2888 pub fn impl_of_method(self, def_id
: DefId
) -> Option
<DefId
> {
2889 self.opt_associated_item(def_id
).and_then(|trait_item
| match trait_item
.container
{
2890 TraitContainer(_
) => None
,
2891 ImplContainer(def_id
) => Some(def_id
),
2895 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2896 /// with the name of the crate containing the impl.
2897 pub fn span_of_impl(self, impl_did
: DefId
) -> Result
<Span
, Symbol
> {
2898 if let Some(impl_did
) = impl_did
.as_local() {
2899 let hir_id
= self.hir().as_local_hir_id(impl_did
);
2900 Ok(self.hir().span(hir_id
))
2902 Err(self.crate_name(impl_did
.krate
))
2906 /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
2907 /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2908 /// definition's parent/scope to perform comparison.
2909 pub fn hygienic_eq(self, use_name
: Ident
, def_name
: Ident
, def_parent_def_id
: DefId
) -> bool
{
2910 // We could use `Ident::eq` here, but we deliberately don't. The name
2911 // comparison fails frequently, and we want to avoid the expensive
2912 // `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
2913 use_name
.name
== def_name
.name
2917 .hygienic_eq(def_name
.span
.ctxt(), self.expansion_that_defined(def_parent_def_id
))
2920 fn expansion_that_defined(self, scope
: DefId
) -> ExpnId
{
2921 match scope
.as_local() {
2922 Some(scope
) => self.hir().definitions().expansion_that_defined(scope
),
2923 None
=> ExpnId
::root(),
2927 pub fn adjust_ident(self, mut ident
: Ident
, scope
: DefId
) -> Ident
{
2928 ident
.span
.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope
));
2932 pub fn adjust_ident_and_get_scope(
2937 ) -> (Ident
, DefId
) {
2939 match ident
.span
.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope
))
2941 Some(actual_expansion
) => {
2942 self.hir().definitions().parent_module_of_macro_def(actual_expansion
)
2944 None
=> self.parent_module(block
).to_def_id(),
2949 pub fn is_object_safe(self, key
: DefId
) -> bool
{
2950 self.object_safety_violations(key
).is_empty()
2954 #[derive(Clone, HashStable)]
2955 pub struct AdtSizedConstraint
<'tcx
>(pub &'tcx
[Ty
<'tcx
>]);
2957 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
2958 pub fn is_impl_trait_defn(tcx
: TyCtxt
<'_
>, def_id
: DefId
) -> Option
<DefId
> {
2959 if let Some(def_id
) = def_id
.as_local() {
2960 if let Node
::Item(item
) = tcx
.hir().get(tcx
.hir().as_local_hir_id(def_id
)) {
2961 if let hir
::ItemKind
::OpaqueTy(ref opaque_ty
) = item
.kind
{
2962 return opaque_ty
.impl_trait_fn
;
2969 pub fn provide(providers
: &mut ty
::query
::Providers
) {
2970 context
::provide(providers
);
2971 erase_regions
::provide(providers
);
2972 layout
::provide(providers
);
2973 super::util
::bug
::provide(providers
);
2974 *providers
= ty
::query
::Providers
{
2975 trait_impls_of
: trait_def
::trait_impls_of_provider
,
2976 all_local_trait_impls
: trait_def
::all_local_trait_impls
,
2981 /// A map for the local crate mapping each type to a vector of its
2982 /// inherent impls. This is not meant to be used outside of coherence;
2983 /// rather, you should request the vector for a specific type via
2984 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
2985 /// (constructing this map requires touching the entire crate).
2986 #[derive(Clone, Debug, Default, HashStable)]
2987 pub struct CrateInherentImpls
{
2988 pub inherent_impls
: DefIdMap
<Vec
<DefId
>>,
2991 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2992 pub struct SymbolName
{
2993 // FIXME: we don't rely on interning or equality here - better have
2994 // this be a `&'tcx str`.
2999 pub fn new(name
: &str) -> SymbolName
{
3000 SymbolName { name: Symbol::intern(name) }
3004 impl PartialOrd
for SymbolName
{
3005 fn partial_cmp(&self, other
: &SymbolName
) -> Option
<Ordering
> {
3006 self.name
.as_str().partial_cmp(&other
.name
.as_str())
3010 /// Ordering must use the chars to ensure reproducible builds.
3011 impl Ord
for SymbolName
{
3012 fn cmp(&self, other
: &SymbolName
) -> Ordering
{
3013 self.name
.as_str().cmp(&other
.name
.as_str())
3017 impl fmt
::Display
for SymbolName
{
3018 fn fmt(&self, fmt
: &mut fmt
::Formatter
<'_
>) -> fmt
::Result
{
3019 fmt
::Display
::fmt(&self.name
, fmt
)
3023 impl fmt
::Debug
for SymbolName
{
3024 fn fmt(&self, fmt
: &mut fmt
::Formatter
<'_
>) -> fmt
::Result
{
3025 fmt
::Display
::fmt(&self.name
, fmt
)