1 pub use self::Variance::*;
2 pub use self::AssociatedItemContainer::*;
3 pub use self::BorrowKind::*;
4 pub use self::IntVarValue::*;
5 pub use self::fold::TypeFoldable;
7 use hir::{map as hir_map, FreevarMap, TraitMap};
9 use hir::def::{Def, CtorKind, ExportMap};
10 use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
11 use hir::map::DefPathData;
12 use rustc_data_structures::svh::Svh;
14 use ich::StableHashingContext;
15 use infer::canonical::Canonical;
16 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
17 use middle::resolve_lifetime::ObjectLifetimeDefault;
19 use mir::interpret::{GlobalId, ErrorHandled};
20 use mir::GeneratorLayout;
21 use session::CrateDisambiguator;
22 use traits::{self, Reveal};
24 use ty::layout::VariantIdx;
25 use ty::subst::{Subst, Substs};
26 use ty::util::{IntTypeExt, Discr};
27 use ty::walk::TypeWalker;
28 use util::captures::Captures;
29 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
30 use arena::SyncDroplessArena;
31 use session::DataTypeKind;
33 use serialize::{self, Encodable, Encoder};
34 use std::cell::RefCell;
35 use std::cmp::{self, Ordering};
37 use std::hash::{Hash, Hasher};
39 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
42 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
44 use syntax::ext::hygiene::Mark;
45 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
46 use syntax_pos::{DUMMY_SP, Span};
49 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
50 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
55 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
56 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
57 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
58 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
59 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
60 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
61 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const, LazyConst};
62 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
63 pub use self::sty::RegionKind;
64 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
65 pub use self::sty::BoundRegion::*;
66 pub use self::sty::InferTy::*;
67 pub use self::sty::RegionKind::*;
68 pub use self::sty::TyKind::*;
70 pub use self::binding::BindingMode;
71 pub use self::binding::BindingMode::*;
73 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
74 pub use self::context::{Lift, TypeckTables, CtxtInterners};
75 pub use self::context::{
76 UserTypeAnnotationIndex, UserTypeAnnotation, CanonicalUserTypeAnnotation,
77 CanonicalUserTypeAnnotations,
80 pub use self::instance::{Instance, InstanceDef};
82 pub use self::trait_def::TraitDef;
84 pub use self::query::queries;
96 pub mod inhabitedness;
113 mod structural_impls;
118 /// The complete set of all analyses described in this module. This is
119 /// produced by the driver and fed to codegen and later passes.
121 /// N.B., these contents are being migrated into queries using the
122 /// *on-demand* infrastructure.
124 pub struct CrateAnalysis {
125 pub glob_map: Option<hir::GlobMap>,
129 pub struct Resolutions {
130 pub freevars: FreevarMap,
131 pub trait_map: TraitMap,
132 pub maybe_unused_trait_imports: NodeSet,
133 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
134 pub export_map: ExportMap,
135 /// Extern prelude entries. The value is `true` if the entry was introduced
136 /// via `extern crate` item and not `--extern` option or compiler built-in.
137 pub extern_prelude: FxHashMap<Name, bool>,
140 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
141 pub enum AssociatedItemContainer {
142 TraitContainer(DefId),
143 ImplContainer(DefId),
146 impl AssociatedItemContainer {
147 /// Asserts that this is the def-id of an associated item declared
148 /// in a trait, and returns the trait def-id.
149 pub fn assert_trait(&self) -> DefId {
151 TraitContainer(id) => id,
152 _ => bug!("associated item has wrong container type: {:?}", self)
156 pub fn id(&self) -> DefId {
158 TraitContainer(id) => id,
159 ImplContainer(id) => id,
164 /// The "header" of an impl is everything outside the body: a Self type, a trait
165 /// ref (in the case of a trait impl), and a set of predicates (from the
166 /// bounds/where clauses).
167 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
168 pub struct ImplHeader<'tcx> {
169 pub impl_def_id: DefId,
170 pub self_ty: Ty<'tcx>,
171 pub trait_ref: Option<TraitRef<'tcx>>,
172 pub predicates: Vec<Predicate<'tcx>>,
175 #[derive(Copy, Clone, Debug, PartialEq)]
176 pub struct AssociatedItem {
179 pub kind: AssociatedKind,
181 pub defaultness: hir::Defaultness,
182 pub container: AssociatedItemContainer,
184 /// Whether this is a method with an explicit self
185 /// as its first argument, allowing method calls.
186 pub method_has_self_argument: bool,
189 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
190 pub enum AssociatedKind {
197 impl AssociatedItem {
198 pub fn def(&self) -> Def {
200 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
201 AssociatedKind::Method => Def::Method(self.def_id),
202 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
203 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
207 /// Tests whether the associated item admits a non-trivial implementation
209 pub fn relevant_for_never<'tcx>(&self) -> bool {
211 AssociatedKind::Existential |
212 AssociatedKind::Const |
213 AssociatedKind::Type => true,
214 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
215 AssociatedKind::Method => !self.method_has_self_argument,
219 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
221 ty::AssociatedKind::Method => {
222 // We skip the binder here because the binder would deanonymize all
223 // late-bound regions, and we don't want method signatures to show up
224 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
225 // regions just fine, showing `fn(&MyType)`.
226 tcx.fn_sig(self.def_id).skip_binder().to_string()
228 ty::AssociatedKind::Type => format!("type {};", self.ident),
229 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
230 ty::AssociatedKind::Const => {
231 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
237 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
238 pub enum Visibility {
239 /// Visible everywhere (including in other crates).
241 /// Visible only in the given crate-local module.
243 /// Not visible anywhere in the local crate. This is the visibility of private external items.
247 pub trait DefIdTree: Copy {
248 fn parent(self, id: DefId) -> Option<DefId>;
250 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
251 if descendant.krate != ancestor.krate {
255 while descendant != ancestor {
256 match self.parent(descendant) {
257 Some(parent) => descendant = parent,
258 None => return false,
265 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
266 fn parent(self, id: DefId) -> Option<DefId> {
267 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
272 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt<'_, '_, '_>) -> Self {
273 match visibility.node {
274 hir::VisibilityKind::Public => Visibility::Public,
275 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
276 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
277 // If there is no resolution, `resolve` will have already reported an error, so
278 // assume that the visibility is public to avoid reporting more privacy errors.
279 Def::Err => Visibility::Public,
280 def => Visibility::Restricted(def.def_id()),
282 hir::VisibilityKind::Inherited => {
283 Visibility::Restricted(tcx.hir().get_module_parent(id))
288 /// Returns `true` if an item with this visibility is accessible from the given block.
289 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
290 let restriction = match self {
291 // Public items are visible everywhere.
292 Visibility::Public => return true,
293 // Private items from other crates are visible nowhere.
294 Visibility::Invisible => return false,
295 // Restricted items are visible in an arbitrary local module.
296 Visibility::Restricted(other) if other.krate != module.krate => return false,
297 Visibility::Restricted(module) => module,
300 tree.is_descendant_of(module, restriction)
303 /// Returns `true` if this visibility is at least as accessible as the given visibility
304 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
305 let vis_restriction = match vis {
306 Visibility::Public => return self == Visibility::Public,
307 Visibility::Invisible => return true,
308 Visibility::Restricted(module) => module,
311 self.is_accessible_from(vis_restriction, tree)
314 // Returns `true` if this item is visible anywhere in the local crate.
315 pub fn is_visible_locally(self) -> bool {
317 Visibility::Public => true,
318 Visibility::Restricted(def_id) => def_id.is_local(),
319 Visibility::Invisible => false,
324 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash)]
326 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
327 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
328 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
329 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
332 /// The crate variances map is computed during typeck and contains the
333 /// variance of every item in the local crate. You should not use it
334 /// directly, because to do so will make your pass dependent on the
335 /// HIR of every item in the local crate. Instead, use
336 /// `tcx.variances_of()` to get the variance for a *particular*
338 pub struct CrateVariancesMap {
339 /// For each item with generics, maps to a vector of the variance
340 /// of its generics. If an item has no generics, it will have no
342 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
344 /// An empty vector, useful for cloning.
345 pub empty_variance: Lrc<Vec<ty::Variance>>,
349 /// `a.xform(b)` combines the variance of a context with the
350 /// variance of a type with the following meaning. If we are in a
351 /// context with variance `a`, and we encounter a type argument in
352 /// a position with variance `b`, then `a.xform(b)` is the new
353 /// variance with which the argument appears.
359 /// Here, the "ambient" variance starts as covariant. `*mut T` is
360 /// invariant with respect to `T`, so the variance in which the
361 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
362 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
363 /// respect to its type argument `T`, and hence the variance of
364 /// the `i32` here is `Invariant.xform(Covariant)`, which results
365 /// (again) in `Invariant`.
369 /// fn(*const Vec<i32>, *mut Vec<i32)
371 /// The ambient variance is covariant. A `fn` type is
372 /// contravariant with respect to its parameters, so the variance
373 /// within which both pointer types appear is
374 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
375 /// T` is covariant with respect to `T`, so the variance within
376 /// which the first `Vec<i32>` appears is
377 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
378 /// is true for its `i32` argument. In the `*mut T` case, the
379 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
380 /// and hence the outermost type is `Invariant` with respect to
381 /// `Vec<i32>` (and its `i32` argument).
383 /// Source: Figure 1 of "Taming the Wildcards:
384 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
385 pub fn xform(self, v: ty::Variance) -> ty::Variance {
387 // Figure 1, column 1.
388 (ty::Covariant, ty::Covariant) => ty::Covariant,
389 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
390 (ty::Covariant, ty::Invariant) => ty::Invariant,
391 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
393 // Figure 1, column 2.
394 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
395 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
396 (ty::Contravariant, ty::Invariant) => ty::Invariant,
397 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
399 // Figure 1, column 3.
400 (ty::Invariant, _) => ty::Invariant,
402 // Figure 1, column 4.
403 (ty::Bivariant, _) => ty::Bivariant,
408 // Contains information needed to resolve types and (in the future) look up
409 // the types of AST nodes.
410 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
411 pub struct CReaderCacheKey {
416 // Flags that we track on types. These flags are propagated upwards
417 // through the type during type construction, so that we can quickly
418 // check whether the type has various kinds of types in it without
419 // recursing over the type itself.
421 pub struct TypeFlags: u32 {
422 const HAS_PARAMS = 1 << 0;
423 const HAS_SELF = 1 << 1;
424 const HAS_TY_INFER = 1 << 2;
425 const HAS_RE_INFER = 1 << 3;
426 const HAS_RE_PLACEHOLDER = 1 << 4;
428 /// Does this have any `ReEarlyBound` regions? Used to
429 /// determine whether substitition is required, since those
430 /// represent regions that are bound in a `ty::Generics` and
431 /// hence may be substituted.
432 const HAS_RE_EARLY_BOUND = 1 << 5;
434 /// Does this have any region that "appears free" in the type?
435 /// Basically anything but `ReLateBound` and `ReErased`.
436 const HAS_FREE_REGIONS = 1 << 6;
438 /// Is an error type reachable?
439 const HAS_TY_ERR = 1 << 7;
440 const HAS_PROJECTION = 1 << 8;
442 // FIXME: Rename this to the actual property since it's used for generators too
443 const HAS_TY_CLOSURE = 1 << 9;
445 // `true` if there are "names" of types and regions and so forth
446 // that are local to a particular fn
447 const HAS_FREE_LOCAL_NAMES = 1 << 10;
449 // Present if the type belongs in a local type context.
450 // Only set for Infer other than Fresh.
451 const KEEP_IN_LOCAL_TCX = 1 << 11;
453 // Is there a projection that does not involve a bound region?
454 // Currently we can't normalize projections w/ bound regions.
455 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
457 /// Does this have any `ReLateBound` regions? Used to check
458 /// if a global bound is safe to evaluate.
459 const HAS_RE_LATE_BOUND = 1 << 13;
461 const HAS_TY_PLACEHOLDER = 1 << 14;
463 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
464 TypeFlags::HAS_SELF.bits |
465 TypeFlags::HAS_RE_EARLY_BOUND.bits;
467 // Flags representing the nominal content of a type,
468 // computed by FlagsComputation. If you add a new nominal
469 // flag, it should be added here too.
470 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
471 TypeFlags::HAS_SELF.bits |
472 TypeFlags::HAS_TY_INFER.bits |
473 TypeFlags::HAS_RE_INFER.bits |
474 TypeFlags::HAS_RE_PLACEHOLDER.bits |
475 TypeFlags::HAS_RE_EARLY_BOUND.bits |
476 TypeFlags::HAS_FREE_REGIONS.bits |
477 TypeFlags::HAS_TY_ERR.bits |
478 TypeFlags::HAS_PROJECTION.bits |
479 TypeFlags::HAS_TY_CLOSURE.bits |
480 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
481 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
482 TypeFlags::HAS_RE_LATE_BOUND.bits |
483 TypeFlags::HAS_TY_PLACEHOLDER.bits;
487 pub struct TyS<'tcx> {
488 pub sty: TyKind<'tcx>,
489 pub flags: TypeFlags,
491 /// This is a kind of confusing thing: it stores the smallest
494 /// (a) the binder itself captures nothing but
495 /// (b) all the late-bound things within the type are captured
496 /// by some sub-binder.
498 /// So, for a type without any late-bound things, like `u32`, this
499 /// will be *innermost*, because that is the innermost binder that
500 /// captures nothing. But for a type `&'D u32`, where `'D` is a
501 /// late-bound region with debruijn index `D`, this would be `D + 1`
502 /// -- the binder itself does not capture `D`, but `D` is captured
503 /// by an inner binder.
505 /// We call this concept an "exclusive" binder `D` because all
506 /// debruijn indices within the type are contained within `0..D`
508 outer_exclusive_binder: ty::DebruijnIndex,
511 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
512 #[cfg(target_arch = "x86_64")]
513 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
515 impl<'tcx> Ord for TyS<'tcx> {
516 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
517 self.sty.cmp(&other.sty)
521 impl<'tcx> PartialOrd for TyS<'tcx> {
522 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
523 Some(self.sty.cmp(&other.sty))
527 impl<'tcx> PartialEq for TyS<'tcx> {
529 fn eq(&self, other: &TyS<'tcx>) -> bool {
533 impl<'tcx> Eq for TyS<'tcx> {}
535 impl<'tcx> Hash for TyS<'tcx> {
536 fn hash<H: Hasher>(&self, s: &mut H) {
537 (self as *const TyS<'_>).hash(s)
541 impl<'tcx> TyS<'tcx> {
542 pub fn is_primitive_ty(&self) -> bool {
549 TyKind::Infer(InferTy::IntVar(_)) |
550 TyKind::Infer(InferTy::FloatVar(_)) |
551 TyKind::Infer(InferTy::FreshIntTy(_)) |
552 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
553 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
558 pub fn is_suggestable(&self) -> bool {
563 TyKind::Dynamic(..) |
564 TyKind::Closure(..) |
566 TyKind::Projection(..) => false,
572 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
573 fn hash_stable<W: StableHasherResult>(&self,
574 hcx: &mut StableHashingContext<'a>,
575 hasher: &mut StableHasher<W>) {
579 // The other fields just provide fast access to information that is
580 // also contained in `sty`, so no need to hash them.
583 outer_exclusive_binder: _,
586 sty.hash_stable(hcx, hasher);
590 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
592 pub type UpvarListMap<'tcx> = FxHashMap<DefId, Vec<UpvarId>>;
594 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
595 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
597 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
600 /// A dummy type used to force List to by unsized without requiring fat pointers
601 type OpaqueListContents;
604 /// A wrapper for slices with the additional invariant
605 /// that the slice is interned and no other slice with
606 /// the same contents can exist in the same context.
607 /// This means we can use pointer for both
608 /// equality comparisons and hashing.
609 /// Note: `Slice` was already taken by the `Ty`.
614 opaque: OpaqueListContents,
617 unsafe impl<T: Sync> Sync for List<T> {}
619 impl<T: Copy> List<T> {
621 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
622 assert!(!mem::needs_drop::<T>());
623 assert!(mem::size_of::<T>() != 0);
624 assert!(slice.len() != 0);
626 // Align up the size of the len (usize) field
627 let align = mem::align_of::<T>();
628 let align_mask = align - 1;
629 let offset = mem::size_of::<usize>();
630 let offset = (offset + align_mask) & !align_mask;
632 let size = offset + slice.len() * mem::size_of::<T>();
634 let mem = arena.alloc_raw(
636 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
638 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
640 result.len = slice.len();
642 // Write the elements
643 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
644 arena_slice.copy_from_slice(slice);
651 impl<T: fmt::Debug> fmt::Debug for List<T> {
652 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
657 impl<T: Encodable> Encodable for List<T> {
659 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
664 impl<T> Ord for List<T> where T: Ord {
665 fn cmp(&self, other: &List<T>) -> Ordering {
666 if self == other { Ordering::Equal } else {
667 <[T] as Ord>::cmp(&**self, &**other)
672 impl<T> PartialOrd for List<T> where T: PartialOrd {
673 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
674 if self == other { Some(Ordering::Equal) } else {
675 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
680 impl<T: PartialEq> PartialEq for List<T> {
682 fn eq(&self, other: &List<T>) -> bool {
686 impl<T: Eq> Eq for List<T> {}
688 impl<T> Hash for List<T> {
690 fn hash<H: Hasher>(&self, s: &mut H) {
691 (self as *const List<T>).hash(s)
695 impl<T> Deref for List<T> {
698 fn deref(&self) -> &[T] {
700 slice::from_raw_parts(self.data.as_ptr(), self.len)
705 impl<'a, T> IntoIterator for &'a List<T> {
707 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
709 fn into_iter(self) -> Self::IntoIter {
714 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
718 pub fn empty<'a>() -> &'a List<T> {
719 #[repr(align(64), C)]
720 struct EmptySlice([u8; 64]);
721 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
722 assert!(mem::align_of::<T>() <= 64);
724 &*(&EMPTY_SLICE as *const _ as *const List<T>)
729 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
730 pub struct UpvarPath {
731 pub hir_id: hir::HirId,
734 /// Upvars do not get their own node-id. Instead, we use the pair of
735 /// the original var id (that is, the root variable that is referenced
736 /// by the upvar) and the id of the closure expression.
737 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
739 pub var_path: UpvarPath,
740 pub closure_expr_id: LocalDefId,
743 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
744 pub enum BorrowKind {
745 /// Data must be immutable and is aliasable.
748 /// Data must be immutable but not aliasable. This kind of borrow
749 /// cannot currently be expressed by the user and is used only in
750 /// implicit closure bindings. It is needed when the closure
751 /// is borrowing or mutating a mutable referent, e.g.:
753 /// let x: &mut isize = ...;
754 /// let y = || *x += 5;
756 /// If we were to try to translate this closure into a more explicit
757 /// form, we'd encounter an error with the code as written:
759 /// struct Env { x: & &mut isize }
760 /// let x: &mut isize = ...;
761 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
762 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
764 /// This is then illegal because you cannot mutate a `&mut` found
765 /// in an aliasable location. To solve, you'd have to translate with
766 /// an `&mut` borrow:
768 /// struct Env { x: & &mut isize }
769 /// let x: &mut isize = ...;
770 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
771 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
773 /// Now the assignment to `**env.x` is legal, but creating a
774 /// mutable pointer to `x` is not because `x` is not mutable. We
775 /// could fix this by declaring `x` as `let mut x`. This is ok in
776 /// user code, if awkward, but extra weird for closures, since the
777 /// borrow is hidden.
779 /// So we introduce a "unique imm" borrow -- the referent is
780 /// immutable, but not aliasable. This solves the problem. For
781 /// simplicity, we don't give users the way to express this
782 /// borrow, it's just used when translating closures.
785 /// Data is mutable and not aliasable.
789 /// Information describing the capture of an upvar. This is computed
790 /// during `typeck`, specifically by `regionck`.
791 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
792 pub enum UpvarCapture<'tcx> {
793 /// Upvar is captured by value. This is always true when the
794 /// closure is labeled `move`, but can also be true in other cases
795 /// depending on inference.
798 /// Upvar is captured by reference.
799 ByRef(UpvarBorrow<'tcx>),
802 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
803 pub struct UpvarBorrow<'tcx> {
804 /// The kind of borrow: by-ref upvars have access to shared
805 /// immutable borrows, which are not part of the normal language
807 pub kind: BorrowKind,
809 /// Region of the resulting reference.
810 pub region: ty::Region<'tcx>,
813 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
815 #[derive(Copy, Clone)]
816 pub struct ClosureUpvar<'tcx> {
822 #[derive(Clone, Copy, PartialEq, Eq)]
823 pub enum IntVarValue {
825 UintType(ast::UintTy),
828 #[derive(Clone, Copy, PartialEq, Eq)]
829 pub struct FloatVarValue(pub ast::FloatTy);
831 impl ty::EarlyBoundRegion {
832 pub fn to_bound_region(&self) -> ty::BoundRegion {
833 ty::BoundRegion::BrNamed(self.def_id, self.name)
836 /// Does this early bound region have a name? Early bound regions normally
837 /// always have names except when using anonymous lifetimes (`'_`).
838 pub fn has_name(&self) -> bool {
839 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
843 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
844 pub enum GenericParamDefKind {
848 object_lifetime_default: ObjectLifetimeDefault,
849 synthetic: Option<hir::SyntheticTyParamKind>,
853 #[derive(Clone, RustcEncodable, RustcDecodable)]
854 pub struct GenericParamDef {
855 pub name: InternedString,
859 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
860 /// on generic parameter `'a`/`T`, asserts data behind the parameter
861 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
862 pub pure_wrt_drop: bool,
864 pub kind: GenericParamDefKind,
867 impl GenericParamDef {
868 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
869 if let GenericParamDefKind::Lifetime = self.kind {
870 ty::EarlyBoundRegion {
876 bug!("cannot convert a non-lifetime parameter def to an early bound region")
880 pub fn to_bound_region(&self) -> ty::BoundRegion {
881 if let GenericParamDefKind::Lifetime = self.kind {
882 self.to_early_bound_region_data().to_bound_region()
884 bug!("cannot convert a non-lifetime parameter def to an early bound region")
890 pub struct GenericParamCount {
891 pub lifetimes: usize,
895 /// Information about the formal type/lifetime parameters associated
896 /// with an item or method. Analogous to `hir::Generics`.
898 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
899 /// `Self` (optionally), `Lifetime` params..., `Type` params...
900 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
901 pub struct Generics {
902 pub parent: Option<DefId>,
903 pub parent_count: usize,
904 pub params: Vec<GenericParamDef>,
906 /// Reverse map to the `index` field of each `GenericParamDef`
907 pub param_def_id_to_index: FxHashMap<DefId, u32>,
910 pub has_late_bound_regions: Option<Span>,
913 impl<'a, 'gcx, 'tcx> Generics {
914 pub fn count(&self) -> usize {
915 self.parent_count + self.params.len()
918 pub fn own_counts(&self) -> GenericParamCount {
919 // We could cache this as a property of `GenericParamCount`, but
920 // the aim is to refactor this away entirely eventually and the
921 // presence of this method will be a constant reminder.
922 let mut own_counts: GenericParamCount = Default::default();
924 for param in &self.params {
926 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
927 GenericParamDefKind::Type { .. } => own_counts.types += 1,
934 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
935 for param in &self.params {
937 GenericParamDefKind::Type { .. } => return true,
938 GenericParamDefKind::Lifetime => {}
941 if let Some(parent_def_id) = self.parent {
942 let parent = tcx.generics_of(parent_def_id);
943 parent.requires_monomorphization(tcx)
949 pub fn region_param(&'tcx self,
950 param: &EarlyBoundRegion,
951 tcx: TyCtxt<'a, 'gcx, 'tcx>)
952 -> &'tcx GenericParamDef
954 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
955 let param = &self.params[index as usize];
957 ty::GenericParamDefKind::Lifetime => param,
958 _ => bug!("expected lifetime parameter, but found another generic parameter")
961 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
962 .region_param(param, tcx)
966 /// Returns the `GenericParamDef` associated with this `ParamTy`.
967 pub fn type_param(&'tcx self,
969 tcx: TyCtxt<'a, 'gcx, 'tcx>)
970 -> &'tcx GenericParamDef {
971 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
972 let param = &self.params[index as usize];
974 ty::GenericParamDefKind::Type {..} => param,
975 _ => bug!("expected type parameter, but found another generic parameter")
978 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
979 .type_param(param, tcx)
984 /// Bounds on generics.
985 #[derive(Clone, Default)]
986 pub struct GenericPredicates<'tcx> {
987 pub parent: Option<DefId>,
988 pub predicates: Vec<(Predicate<'tcx>, Span)>,
991 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
992 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
994 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
995 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
996 -> InstantiatedPredicates<'tcx> {
997 let mut instantiated = InstantiatedPredicates::empty();
998 self.instantiate_into(tcx, &mut instantiated, substs);
1002 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1003 -> InstantiatedPredicates<'tcx> {
1004 InstantiatedPredicates {
1005 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1009 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1010 instantiated: &mut InstantiatedPredicates<'tcx>,
1011 substs: &Substs<'tcx>) {
1012 if let Some(def_id) = self.parent {
1013 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1015 instantiated.predicates.extend(
1016 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1020 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1021 -> InstantiatedPredicates<'tcx> {
1022 let mut instantiated = InstantiatedPredicates::empty();
1023 self.instantiate_identity_into(tcx, &mut instantiated);
1027 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1028 instantiated: &mut InstantiatedPredicates<'tcx>) {
1029 if let Some(def_id) = self.parent {
1030 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1032 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1035 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1036 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1037 -> InstantiatedPredicates<'tcx>
1039 assert_eq!(self.parent, None);
1040 InstantiatedPredicates {
1041 predicates: self.predicates.iter().map(|(pred, _)| {
1042 pred.subst_supertrait(tcx, poly_trait_ref)
1048 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1049 pub enum Predicate<'tcx> {
1050 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1051 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1052 /// would be the type parameters.
1053 Trait(PolyTraitPredicate<'tcx>),
1056 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1059 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1061 /// where `<T as TraitRef>::Name == X`, approximately.
1062 /// See the `ProjectionPredicate` struct for details.
1063 Projection(PolyProjectionPredicate<'tcx>),
1065 /// no syntax: `T` well-formed
1066 WellFormed(Ty<'tcx>),
1068 /// trait must be object-safe
1071 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1072 /// for some substitutions `...` and `T` being a closure type.
1073 /// Satisfied (or refuted) once we know the closure's kind.
1074 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1077 Subtype(PolySubtypePredicate<'tcx>),
1079 /// Constant initializer must evaluate successfully.
1080 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1083 /// The crate outlives map is computed during typeck and contains the
1084 /// outlives of every item in the local crate. You should not use it
1085 /// directly, because to do so will make your pass dependent on the
1086 /// HIR of every item in the local crate. Instead, use
1087 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1089 pub struct CratePredicatesMap<'tcx> {
1090 /// For each struct with outlive bounds, maps to a vector of the
1091 /// predicate of its outlive bounds. If an item has no outlives
1092 /// bounds, it will have no entry.
1093 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1095 /// An empty vector, useful for cloning.
1096 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1099 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1100 fn as_ref(&self) -> &Predicate<'tcx> {
1105 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1106 /// Performs a substitution suitable for going from a
1107 /// poly-trait-ref to supertraits that must hold if that
1108 /// poly-trait-ref holds. This is slightly different from a normal
1109 /// substitution in terms of what happens with bound regions. See
1110 /// lengthy comment below for details.
1111 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1112 trait_ref: &ty::PolyTraitRef<'tcx>)
1113 -> ty::Predicate<'tcx>
1115 // The interaction between HRTB and supertraits is not entirely
1116 // obvious. Let me walk you (and myself) through an example.
1118 // Let's start with an easy case. Consider two traits:
1120 // trait Foo<'a>: Bar<'a,'a> { }
1121 // trait Bar<'b,'c> { }
1123 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1124 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1125 // knew that `Foo<'x>` (for any 'x) then we also know that
1126 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1127 // normal substitution.
1129 // In terms of why this is sound, the idea is that whenever there
1130 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1131 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1132 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1135 // Another example to be careful of is this:
1137 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1138 // trait Bar1<'b,'c> { }
1140 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1141 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1142 // reason is similar to the previous example: any impl of
1143 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1144 // basically we would want to collapse the bound lifetimes from
1145 // the input (`trait_ref`) and the supertraits.
1147 // To achieve this in practice is fairly straightforward. Let's
1148 // consider the more complicated scenario:
1150 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1151 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1152 // where both `'x` and `'b` would have a DB index of 1.
1153 // The substitution from the input trait-ref is therefore going to be
1154 // `'a => 'x` (where `'x` has a DB index of 1).
1155 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1156 // early-bound parameter and `'b' is a late-bound parameter with a
1158 // - If we replace `'a` with `'x` from the input, it too will have
1159 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1160 // just as we wanted.
1162 // There is only one catch. If we just apply the substitution `'a
1163 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1164 // adjust the DB index because we substituting into a binder (it
1165 // tries to be so smart...) resulting in `for<'x> for<'b>
1166 // Bar1<'x,'b>` (we have no syntax for this, so use your
1167 // imagination). Basically the 'x will have DB index of 2 and 'b
1168 // will have DB index of 1. Not quite what we want. So we apply
1169 // the substitution to the *contents* of the trait reference,
1170 // rather than the trait reference itself (put another way, the
1171 // substitution code expects equal binding levels in the values
1172 // from the substitution and the value being substituted into, and
1173 // this trick achieves that).
1175 let substs = &trait_ref.skip_binder().substs;
1177 Predicate::Trait(ref binder) =>
1178 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1179 Predicate::Subtype(ref binder) =>
1180 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1181 Predicate::RegionOutlives(ref binder) =>
1182 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1183 Predicate::TypeOutlives(ref binder) =>
1184 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1185 Predicate::Projection(ref binder) =>
1186 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1187 Predicate::WellFormed(data) =>
1188 Predicate::WellFormed(data.subst(tcx, substs)),
1189 Predicate::ObjectSafe(trait_def_id) =>
1190 Predicate::ObjectSafe(trait_def_id),
1191 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1192 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1193 Predicate::ConstEvaluatable(def_id, const_substs) =>
1194 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1199 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1200 pub struct TraitPredicate<'tcx> {
1201 pub trait_ref: TraitRef<'tcx>
1204 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1206 impl<'tcx> TraitPredicate<'tcx> {
1207 pub fn def_id(&self) -> DefId {
1208 self.trait_ref.def_id
1211 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1212 self.trait_ref.input_types()
1215 pub fn self_ty(&self) -> Ty<'tcx> {
1216 self.trait_ref.self_ty()
1220 impl<'tcx> PolyTraitPredicate<'tcx> {
1221 pub fn def_id(&self) -> DefId {
1222 // ok to skip binder since trait def-id does not care about regions
1223 self.skip_binder().def_id()
1227 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1228 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1229 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1230 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1232 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1234 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1235 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1237 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1238 pub struct SubtypePredicate<'tcx> {
1239 pub a_is_expected: bool,
1243 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1245 /// This kind of predicate has no *direct* correspondent in the
1246 /// syntax, but it roughly corresponds to the syntactic forms:
1248 /// 1. `T: TraitRef<..., Item=Type>`
1249 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1251 /// In particular, form #1 is "desugared" to the combination of a
1252 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1253 /// predicates. Form #2 is a broader form in that it also permits
1254 /// equality between arbitrary types. Processing an instance of
1255 /// Form #2 eventually yields one of these `ProjectionPredicate`
1256 /// instances to normalize the LHS.
1257 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1258 pub struct ProjectionPredicate<'tcx> {
1259 pub projection_ty: ProjectionTy<'tcx>,
1263 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1265 impl<'tcx> PolyProjectionPredicate<'tcx> {
1266 /// Returns the `DefId` of the associated item being projected.
1267 pub fn item_def_id(&self) -> DefId {
1268 self.skip_binder().projection_ty.item_def_id
1272 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1273 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1274 // `self.0.trait_ref` is permitted to have escaping regions.
1275 // This is because here `self` has a `Binder` and so does our
1276 // return value, so we are preserving the number of binding
1278 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1281 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1282 self.map_bound(|predicate| predicate.ty)
1285 /// The `DefId` of the `TraitItem` for the associated type.
1287 /// Note that this is not the `DefId` of the `TraitRef` containing this
1288 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1289 pub fn projection_def_id(&self) -> DefId {
1290 // okay to skip binder since trait def-id does not care about regions
1291 self.skip_binder().projection_ty.item_def_id
1295 pub trait ToPolyTraitRef<'tcx> {
1296 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1299 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1300 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1301 ty::Binder::dummy(self.clone())
1305 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1306 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1307 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1311 pub trait ToPredicate<'tcx> {
1312 fn to_predicate(&self) -> Predicate<'tcx>;
1315 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1316 fn to_predicate(&self) -> Predicate<'tcx> {
1317 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1318 trait_ref: self.clone()
1323 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1324 fn to_predicate(&self) -> Predicate<'tcx> {
1325 ty::Predicate::Trait(self.to_poly_trait_predicate())
1329 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1330 fn to_predicate(&self) -> Predicate<'tcx> {
1331 Predicate::RegionOutlives(self.clone())
1335 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1336 fn to_predicate(&self) -> Predicate<'tcx> {
1337 Predicate::TypeOutlives(self.clone())
1341 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1342 fn to_predicate(&self) -> Predicate<'tcx> {
1343 Predicate::Projection(self.clone())
1347 // A custom iterator used by Predicate::walk_tys.
1348 enum WalkTysIter<'tcx, I, J, K>
1349 where I: Iterator<Item = Ty<'tcx>>,
1350 J: Iterator<Item = Ty<'tcx>>,
1351 K: Iterator<Item = Ty<'tcx>>
1355 Two(Ty<'tcx>, Ty<'tcx>),
1361 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1362 where I: Iterator<Item = Ty<'tcx>>,
1363 J: Iterator<Item = Ty<'tcx>>,
1364 K: Iterator<Item = Ty<'tcx>>
1366 type Item = Ty<'tcx>;
1368 fn next(&mut self) -> Option<Ty<'tcx>> {
1370 WalkTysIter::None => None,
1371 WalkTysIter::One(item) => {
1372 *self = WalkTysIter::None;
1375 WalkTysIter::Two(item1, item2) => {
1376 *self = WalkTysIter::One(item2);
1379 WalkTysIter::Types(ref mut iter) => {
1382 WalkTysIter::InputTypes(ref mut iter) => {
1385 WalkTysIter::ProjectionTypes(ref mut iter) => {
1392 impl<'tcx> Predicate<'tcx> {
1393 /// Iterates over the types in this predicate. Note that in all
1394 /// cases this is skipping over a binder, so late-bound regions
1395 /// with depth 0 are bound by the predicate.
1396 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1398 ty::Predicate::Trait(ref data) => {
1399 WalkTysIter::InputTypes(data.skip_binder().input_types())
1401 ty::Predicate::Subtype(binder) => {
1402 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1403 WalkTysIter::Two(a, b)
1405 ty::Predicate::TypeOutlives(binder) => {
1406 WalkTysIter::One(binder.skip_binder().0)
1408 ty::Predicate::RegionOutlives(..) => {
1411 ty::Predicate::Projection(ref data) => {
1412 let inner = data.skip_binder();
1413 WalkTysIter::ProjectionTypes(
1414 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1416 ty::Predicate::WellFormed(data) => {
1417 WalkTysIter::One(data)
1419 ty::Predicate::ObjectSafe(_trait_def_id) => {
1422 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1423 WalkTysIter::Types(closure_substs.substs.types())
1425 ty::Predicate::ConstEvaluatable(_, substs) => {
1426 WalkTysIter::Types(substs.types())
1431 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1433 Predicate::Trait(ref t) => {
1434 Some(t.to_poly_trait_ref())
1436 Predicate::Projection(..) |
1437 Predicate::Subtype(..) |
1438 Predicate::RegionOutlives(..) |
1439 Predicate::WellFormed(..) |
1440 Predicate::ObjectSafe(..) |
1441 Predicate::ClosureKind(..) |
1442 Predicate::TypeOutlives(..) |
1443 Predicate::ConstEvaluatable(..) => {
1449 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1451 Predicate::TypeOutlives(data) => {
1454 Predicate::Trait(..) |
1455 Predicate::Projection(..) |
1456 Predicate::Subtype(..) |
1457 Predicate::RegionOutlives(..) |
1458 Predicate::WellFormed(..) |
1459 Predicate::ObjectSafe(..) |
1460 Predicate::ClosureKind(..) |
1461 Predicate::ConstEvaluatable(..) => {
1468 /// Represents the bounds declared on a particular set of type
1469 /// parameters. Should eventually be generalized into a flag list of
1470 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1471 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1472 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1473 /// the `GenericPredicates` are expressed in terms of the bound type
1474 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1475 /// represented a set of bounds for some particular instantiation,
1476 /// meaning that the generic parameters have been substituted with
1481 /// struct Foo<T,U:Bar<T>> { ... }
1483 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1484 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1485 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1486 /// [usize:Bar<isize>]]`.
1488 pub struct InstantiatedPredicates<'tcx> {
1489 pub predicates: Vec<Predicate<'tcx>>,
1492 impl<'tcx> InstantiatedPredicates<'tcx> {
1493 pub fn empty() -> InstantiatedPredicates<'tcx> {
1494 InstantiatedPredicates { predicates: vec![] }
1497 pub fn is_empty(&self) -> bool {
1498 self.predicates.is_empty()
1502 /// "Universes" are used during type- and trait-checking in the
1503 /// presence of `for<..>` binders to control what sets of names are
1504 /// visible. Universes are arranged into a tree: the root universe
1505 /// contains names that are always visible. Each child then adds a new
1506 /// set of names that are visible, in addition to those of its parent.
1507 /// We say that the child universe "extends" the parent universe with
1510 /// To make this more concrete, consider this program:
1514 /// fn bar<T>(x: T) {
1515 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1519 /// The struct name `Foo` is in the root universe U0. But the type
1520 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1521 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1522 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1523 /// region `'a` is in a universe U2 that extends U1, because we can
1524 /// name it inside the fn type but not outside.
1526 /// Universes are used to do type- and trait-checking around these
1527 /// "forall" binders (also called **universal quantification**). The
1528 /// idea is that when, in the body of `bar`, we refer to `T` as a
1529 /// type, we aren't referring to any type in particular, but rather a
1530 /// kind of "fresh" type that is distinct from all other types we have
1531 /// actually declared. This is called a **placeholder** type, and we
1532 /// use universes to talk about this. In other words, a type name in
1533 /// universe 0 always corresponds to some "ground" type that the user
1534 /// declared, but a type name in a non-zero universe is a placeholder
1535 /// type -- an idealized representative of "types in general" that we
1536 /// use for checking generic functions.
1538 pub struct UniverseIndex {
1539 DEBUG_FORMAT = "U{}",
1543 impl_stable_hash_for!(struct UniverseIndex { private });
1545 impl UniverseIndex {
1546 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1548 /// Returns the "next" universe index in order -- this new index
1549 /// is considered to extend all previous universes. This
1550 /// corresponds to entering a `forall` quantifier. So, for
1551 /// example, suppose we have this type in universe `U`:
1554 /// for<'a> fn(&'a u32)
1557 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1558 /// new universe that extends `U` -- in this new universe, we can
1559 /// name the region `'a`, but that region was not nameable from
1560 /// `U` because it was not in scope there.
1561 pub fn next_universe(self) -> UniverseIndex {
1562 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1565 /// Returns `true` if `self` can name a name from `other` -- in other words,
1566 /// if the set of names in `self` is a superset of those in
1567 /// `other` (`self >= other`).
1568 pub fn can_name(self, other: UniverseIndex) -> bool {
1569 self.private >= other.private
1572 /// Returns `true` if `self` cannot name some names from `other` -- in other
1573 /// words, if the set of names in `self` is a strict subset of
1574 /// those in `other` (`self < other`).
1575 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1576 self.private < other.private
1580 /// The "placeholder index" fully defines a placeholder region.
1581 /// Placeholder regions are identified by both a **universe** as well
1582 /// as a "bound-region" within that universe. The `bound_region` is
1583 /// basically a name -- distinct bound regions within the same
1584 /// universe are just two regions with an unknown relationship to one
1586 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1587 pub struct Placeholder<T> {
1588 pub universe: UniverseIndex,
1592 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1593 where T: HashStable<StableHashingContext<'a>>
1595 fn hash_stable<W: StableHasherResult>(
1597 hcx: &mut StableHashingContext<'a>,
1598 hasher: &mut StableHasher<W>
1600 self.universe.hash_stable(hcx, hasher);
1601 self.name.hash_stable(hcx, hasher);
1605 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1607 pub type PlaceholderType = Placeholder<BoundVar>;
1609 /// When type checking, we use the `ParamEnv` to track
1610 /// details about the set of where-clauses that are in scope at this
1611 /// particular point.
1612 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1613 pub struct ParamEnv<'tcx> {
1614 /// Obligations that the caller must satisfy. This is basically
1615 /// the set of bounds on the in-scope type parameters, translated
1616 /// into Obligations, and elaborated and normalized.
1617 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1619 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1620 /// want `Reveal::All` -- note that this is always paired with an
1621 /// empty environment. To get that, use `ParamEnv::reveal()`.
1622 pub reveal: traits::Reveal,
1624 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1625 /// register that `def_id` (useful for transitioning to the chalk trait
1627 pub def_id: Option<DefId>,
1630 impl<'tcx> ParamEnv<'tcx> {
1631 /// Construct a trait environment suitable for contexts where
1632 /// there are no where clauses in scope. Hidden types (like `impl
1633 /// Trait`) are left hidden, so this is suitable for ordinary
1636 pub fn empty() -> Self {
1637 Self::new(List::empty(), Reveal::UserFacing, None)
1640 /// Construct a trait environment with no where clauses in scope
1641 /// where the values of all `impl Trait` and other hidden types
1642 /// are revealed. This is suitable for monomorphized, post-typeck
1643 /// environments like codegen or doing optimizations.
1645 /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
1646 /// or invoke `param_env.with_reveal_all()`.
1648 pub fn reveal_all() -> Self {
1649 Self::new(List::empty(), Reveal::All, None)
1652 /// Construct a trait environment with the given set of predicates.
1655 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1657 def_id: Option<DefId>
1659 ty::ParamEnv { caller_bounds, reveal, def_id }
1662 /// Returns a new parameter environment with the same clauses, but
1663 /// which "reveals" the true results of projections in all cases
1664 /// (even for associated types that are specializable). This is
1665 /// the desired behavior during codegen and certain other special
1666 /// contexts; normally though we want to use `Reveal::UserFacing`,
1667 /// which is the default.
1668 pub fn with_reveal_all(self) -> Self {
1669 ty::ParamEnv { reveal: Reveal::All, ..self }
1672 /// Returns this same environment but with no caller bounds.
1673 pub fn without_caller_bounds(self) -> Self {
1674 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1677 /// Creates a suitable environment in which to perform trait
1678 /// queries on the given value. When type-checking, this is simply
1679 /// the pair of the environment plus value. But when reveal is set to
1680 /// All, then if `value` does not reference any type parameters, we will
1681 /// pair it with the empty environment. This improves caching and is generally
1684 /// N.B., we preserve the environment when type-checking because it
1685 /// is possible for the user to have wacky where-clauses like
1686 /// `where Box<u32>: Copy`, which are clearly never
1687 /// satisfiable. We generally want to behave as if they were true,
1688 /// although the surrounding function is never reachable.
1689 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1691 Reveal::UserFacing => {
1699 if value.has_placeholders()
1700 || value.needs_infer()
1701 || value.has_param_types()
1702 || value.has_self_ty()
1710 param_env: self.without_caller_bounds(),
1719 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1720 pub struct ParamEnvAnd<'tcx, T> {
1721 pub param_env: ParamEnv<'tcx>,
1725 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1726 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1727 (self.param_env, self.value)
1731 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1732 where T: HashStable<StableHashingContext<'a>>
1734 fn hash_stable<W: StableHasherResult>(&self,
1735 hcx: &mut StableHashingContext<'a>,
1736 hasher: &mut StableHasher<W>) {
1742 param_env.hash_stable(hcx, hasher);
1743 value.hash_stable(hcx, hasher);
1747 #[derive(Copy, Clone, Debug)]
1748 pub struct Destructor {
1749 /// The def-id of the destructor method
1754 pub struct AdtFlags: u32 {
1755 const NO_ADT_FLAGS = 0;
1756 const IS_ENUM = 1 << 0;
1757 const IS_UNION = 1 << 1;
1758 const IS_STRUCT = 1 << 2;
1759 const HAS_CTOR = 1 << 3;
1760 const IS_PHANTOM_DATA = 1 << 4;
1761 const IS_FUNDAMENTAL = 1 << 5;
1762 const IS_BOX = 1 << 6;
1763 /// Indicates whether the type is an `Arc`.
1764 const IS_ARC = 1 << 7;
1765 /// Indicates whether the type is an `Rc`.
1766 const IS_RC = 1 << 8;
1767 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1768 /// (i.e., this flag is never set unless this ADT is an enum).
1769 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1774 pub struct VariantFlags: u32 {
1775 const NO_VARIANT_FLAGS = 0;
1776 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1777 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1782 pub struct VariantDef {
1783 /// The variant's `DefId`. If this is a tuple-like struct,
1784 /// this is the `DefId` of the struct's ctor.
1786 pub ident: Ident, // struct's name if this is a struct
1787 pub discr: VariantDiscr,
1788 pub fields: Vec<FieldDef>,
1789 pub ctor_kind: CtorKind,
1790 flags: VariantFlags,
1793 impl<'a, 'gcx, 'tcx> VariantDef {
1794 /// Create a new `VariantDef`.
1796 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1797 /// and for everything else, it is the variant DefId.
1798 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1799 /// this is the struct DefId for structs, and the variant DefId for variants.
1801 /// Note that we *could* use the constructor DefId, because the constructor attributes
1802 /// redirect to the base attributes, but compiling a small crate requires
1803 /// loading the AdtDefs for all the structs in the universe (e.g., coherence for any
1804 /// built-in trait), and we do not want to load attributes twice.
1806 /// If someone speeds up attribute loading to not be a performance concern, they can
1807 /// remove this hack and use the constructor DefId everywhere.
1808 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1811 discr: VariantDiscr,
1812 fields: Vec<FieldDef>,
1814 ctor_kind: CtorKind,
1815 attribute_def_id: DefId)
1818 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, ident, discr,
1819 fields, adt_kind, ctor_kind, attribute_def_id);
1820 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1821 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1822 debug!("found non-exhaustive field list for {:?}", did);
1823 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1836 pub fn is_field_list_non_exhaustive(&self) -> bool {
1837 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1841 impl_stable_hash_for!(struct VariantDef {
1843 ident -> (ident.name),
1850 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1851 pub enum VariantDiscr {
1852 /// Explicit value for this variant, i.e., `X = 123`.
1853 /// The `DefId` corresponds to the embedded constant.
1856 /// The previous variant's discriminant plus one.
1857 /// For efficiency reasons, the distance from the
1858 /// last `Explicit` discriminant is being stored,
1859 /// or `0` for the first variant, if it has none.
1864 pub struct FieldDef {
1867 pub vis: Visibility,
1870 /// The definition of an abstract data type -- a struct or enum.
1872 /// These are all interned (by `intern_adt_def`) into the `adt_defs`
1876 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1878 pub repr: ReprOptions,
1881 impl PartialOrd for AdtDef {
1882 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1883 Some(self.cmp(&other))
1887 /// There should be only one AdtDef for each `did`, therefore
1888 /// it is fine to implement `Ord` only based on `did`.
1889 impl Ord for AdtDef {
1890 fn cmp(&self, other: &AdtDef) -> Ordering {
1891 self.did.cmp(&other.did)
1895 impl PartialEq for AdtDef {
1896 // AdtDef are always interned and this is part of TyS equality
1898 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1901 impl Eq for AdtDef {}
1903 impl Hash for AdtDef {
1905 fn hash<H: Hasher>(&self, s: &mut H) {
1906 (self as *const AdtDef).hash(s)
1910 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1911 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1916 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1919 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1920 fn hash_stable<W: StableHasherResult>(&self,
1921 hcx: &mut StableHashingContext<'a>,
1922 hasher: &mut StableHasher<W>) {
1924 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1927 let hash: Fingerprint = CACHE.with(|cache| {
1928 let addr = self as *const AdtDef as usize;
1929 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1937 let mut hasher = StableHasher::new();
1938 did.hash_stable(hcx, &mut hasher);
1939 variants.hash_stable(hcx, &mut hasher);
1940 flags.hash_stable(hcx, &mut hasher);
1941 repr.hash_stable(hcx, &mut hasher);
1947 hash.hash_stable(hcx, hasher);
1951 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1952 pub enum AdtKind { Struct, Union, Enum }
1954 impl Into<DataTypeKind> for AdtKind {
1955 fn into(self) -> DataTypeKind {
1957 AdtKind::Struct => DataTypeKind::Struct,
1958 AdtKind::Union => DataTypeKind::Union,
1959 AdtKind::Enum => DataTypeKind::Enum,
1965 #[derive(RustcEncodable, RustcDecodable, Default)]
1966 pub struct ReprFlags: u8 {
1967 const IS_C = 1 << 0;
1968 const IS_SIMD = 1 << 1;
1969 const IS_TRANSPARENT = 1 << 2;
1970 // Internal only for now. If true, don't reorder fields.
1971 const IS_LINEAR = 1 << 3;
1973 // Any of these flags being set prevent field reordering optimisation.
1974 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1975 ReprFlags::IS_SIMD.bits |
1976 ReprFlags::IS_LINEAR.bits;
1980 impl_stable_hash_for!(struct ReprFlags {
1984 /// Represents the repr options provided by the user,
1985 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1986 pub struct ReprOptions {
1987 pub int: Option<attr::IntType>,
1990 pub flags: ReprFlags,
1993 impl_stable_hash_for!(struct ReprOptions {
2001 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
2002 let mut flags = ReprFlags::empty();
2003 let mut size = None;
2004 let mut max_align = 0;
2005 let mut min_pack = 0;
2006 for attr in tcx.get_attrs(did).iter() {
2007 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2008 flags.insert(match r {
2009 attr::ReprC => ReprFlags::IS_C,
2010 attr::ReprPacked(pack) => {
2011 min_pack = if min_pack > 0 {
2012 cmp::min(pack, min_pack)
2018 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2019 attr::ReprSimd => ReprFlags::IS_SIMD,
2020 attr::ReprInt(i) => {
2024 attr::ReprAlign(align) => {
2025 max_align = cmp::max(align, max_align);
2032 // This is here instead of layout because the choice must make it into metadata.
2033 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
2034 flags.insert(ReprFlags::IS_LINEAR);
2036 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2040 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2042 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2044 pub fn packed(&self) -> bool { self.pack > 0 }
2046 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2048 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2050 pub fn discr_type(&self) -> attr::IntType {
2051 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2054 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2055 /// layout" optimizations, such as representing `Foo<&T>` as a
2057 pub fn inhibit_enum_layout_opt(&self) -> bool {
2058 self.c() || self.int.is_some()
2061 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2062 /// optimizations, such as with repr(C), repr(packed(1)), or repr(<int>).
2063 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2064 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
2068 /// Returns true if this `#[repr()]` should inhibit union abi optimisations
2069 pub fn inhibit_union_abi_opt(&self) -> bool {
2075 impl<'a, 'gcx, 'tcx> AdtDef {
2076 fn new(tcx: TyCtxt<'_, '_, '_>,
2079 variants: IndexVec<VariantIdx, VariantDef>,
2080 repr: ReprOptions) -> Self {
2081 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2082 let mut flags = AdtFlags::NO_ADT_FLAGS;
2084 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2085 debug!("found non-exhaustive variant list for {:?}", did);
2086 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2088 flags |= match kind {
2089 AdtKind::Enum => AdtFlags::IS_ENUM,
2090 AdtKind::Union => AdtFlags::IS_UNION,
2091 AdtKind::Struct => AdtFlags::IS_STRUCT,
2094 if let AdtKind::Struct = kind {
2095 let variant_def = &variants[VariantIdx::new(0)];
2096 let def_key = tcx.def_key(variant_def.did);
2097 match def_key.disambiguated_data.data {
2098 DefPathData::StructCtor => flags |= AdtFlags::HAS_CTOR,
2103 let attrs = tcx.get_attrs(did);
2104 if attr::contains_name(&attrs, "fundamental") {
2105 flags |= AdtFlags::IS_FUNDAMENTAL;
2107 if Some(did) == tcx.lang_items().phantom_data() {
2108 flags |= AdtFlags::IS_PHANTOM_DATA;
2110 if Some(did) == tcx.lang_items().owned_box() {
2111 flags |= AdtFlags::IS_BOX;
2113 if Some(did) == tcx.lang_items().arc() {
2114 flags |= AdtFlags::IS_ARC;
2116 if Some(did) == tcx.lang_items().rc() {
2117 flags |= AdtFlags::IS_RC;
2129 pub fn is_struct(&self) -> bool {
2130 self.flags.contains(AdtFlags::IS_STRUCT)
2134 pub fn is_union(&self) -> bool {
2135 self.flags.contains(AdtFlags::IS_UNION)
2139 pub fn is_enum(&self) -> bool {
2140 self.flags.contains(AdtFlags::IS_ENUM)
2144 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2145 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2148 /// Returns the kind of the ADT.
2150 pub fn adt_kind(&self) -> AdtKind {
2153 } else if self.is_union() {
2160 pub fn descr(&self) -> &'static str {
2161 match self.adt_kind() {
2162 AdtKind::Struct => "struct",
2163 AdtKind::Union => "union",
2164 AdtKind::Enum => "enum",
2169 pub fn variant_descr(&self) -> &'static str {
2170 match self.adt_kind() {
2171 AdtKind::Struct => "struct",
2172 AdtKind::Union => "union",
2173 AdtKind::Enum => "variant",
2177 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2179 pub fn has_ctor(&self) -> bool {
2180 self.flags.contains(AdtFlags::HAS_CTOR)
2183 /// Returns whether this type is `#[fundamental]` for the purposes
2184 /// of coherence checking.
2186 pub fn is_fundamental(&self) -> bool {
2187 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2190 /// Returns `true` if this is PhantomData<T>.
2192 pub fn is_phantom_data(&self) -> bool {
2193 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2196 /// Returns `true` if this is `Arc<T>`.
2197 pub fn is_arc(&self) -> bool {
2198 self.flags.contains(AdtFlags::IS_ARC)
2201 /// Returns `true` if this is `Rc<T>`.
2202 pub fn is_rc(&self) -> bool {
2203 self.flags.contains(AdtFlags::IS_RC)
2206 /// Returns `true` if this is Box<T>.
2208 pub fn is_box(&self) -> bool {
2209 self.flags.contains(AdtFlags::IS_BOX)
2212 /// Returns whether this type has a destructor.
2213 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2214 self.destructor(tcx).is_some()
2217 /// Asserts this is a struct or union and returns its unique variant.
2218 pub fn non_enum_variant(&self) -> &VariantDef {
2219 assert!(self.is_struct() || self.is_union());
2220 &self.variants[VariantIdx::new(0)]
2224 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2225 tcx.predicates_of(self.did)
2228 /// Returns an iterator over all fields contained
2231 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2232 self.variants.iter().flat_map(|v| v.fields.iter())
2235 pub fn is_payloadfree(&self) -> bool {
2236 !self.variants.is_empty() &&
2237 self.variants.iter().all(|v| v.fields.is_empty())
2240 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2243 .find(|v| v.did == vid)
2244 .expect("variant_with_id: unknown variant")
2247 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2250 .find(|(_, v)| v.did == vid)
2251 .expect("variant_index_with_id: unknown variant")
2255 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2257 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2258 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2259 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2260 Def::SelfCtor(..) => self.non_enum_variant(),
2261 _ => bug!("unexpected def {:?} in variant_of_def", def)
2266 pub fn eval_explicit_discr(
2268 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2270 ) -> Option<Discr<'tcx>> {
2271 let param_env = ParamEnv::empty();
2272 let repr_type = self.repr.discr_type();
2273 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2274 let instance = ty::Instance::new(expr_did, substs);
2275 let cid = GlobalId {
2279 match tcx.const_eval(param_env.and(cid)) {
2281 // FIXME: Find the right type and use it instead of `val.ty` here
2282 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2283 trace!("discriminants: {} ({:?})", b, repr_type);
2289 info!("invalid enum discriminant: {:#?}", val);
2290 ::mir::interpret::struct_error(
2291 tcx.at(tcx.def_span(expr_did)),
2292 "constant evaluation of enum discriminant resulted in non-integer",
2297 Err(ErrorHandled::Reported) => {
2298 if !expr_did.is_local() {
2299 span_bug!(tcx.def_span(expr_did),
2300 "variant discriminant evaluation succeeded \
2301 in its crate but failed locally");
2305 Err(ErrorHandled::TooGeneric) => span_bug!(
2306 tcx.def_span(expr_did),
2307 "enum discriminant depends on generic arguments",
2313 pub fn discriminants(
2315 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2316 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2317 let repr_type = self.repr.discr_type();
2318 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2319 let mut prev_discr = None::<Discr<'tcx>>;
2320 self.variants.iter_enumerated().map(move |(i, v)| {
2321 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2322 if let VariantDiscr::Explicit(expr_did) = v.discr {
2323 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2327 prev_discr = Some(discr);
2333 /// Compute the discriminant value used by a specific variant.
2334 /// Unlike `discriminants`, this is (amortized) constant-time,
2335 /// only doing at most one query for evaluating an explicit
2336 /// discriminant (the last one before the requested variant),
2337 /// assuming there are no constant-evaluation errors there.
2338 pub fn discriminant_for_variant(&self,
2339 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2340 variant_index: VariantIdx)
2342 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2343 let explicit_value = val
2344 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2345 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2346 explicit_value.checked_add(tcx, offset as u128).0
2349 /// Yields a DefId for the discriminant and an offset to add to it
2350 /// Alternatively, if there is no explicit discriminant, returns the
2351 /// inferred discriminant directly
2352 pub fn discriminant_def_for_variant(
2354 variant_index: VariantIdx,
2355 ) -> (Option<DefId>, u32) {
2356 let mut explicit_index = variant_index.as_u32();
2359 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2360 ty::VariantDiscr::Relative(0) => {
2364 ty::VariantDiscr::Relative(distance) => {
2365 explicit_index -= distance;
2367 ty::VariantDiscr::Explicit(did) => {
2368 expr_did = Some(did);
2373 (expr_did, variant_index.as_u32() - explicit_index)
2376 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2377 tcx.adt_destructor(self.did)
2380 /// Returns a list of types such that `Self: Sized` if and only
2381 /// if that type is Sized, or `TyErr` if this type is recursive.
2383 /// Oddly enough, checking that the sized-constraint is Sized is
2384 /// actually more expressive than checking all members:
2385 /// the Sized trait is inductive, so an associated type that references
2386 /// Self would prevent its containing ADT from being Sized.
2388 /// Due to normalization being eager, this applies even if
2389 /// the associated type is behind a pointer, e.g., issue #31299.
2390 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2391 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2394 debug!("adt_sized_constraint: {:?} is recursive", self);
2395 // This should be reported as an error by `check_representable`.
2397 // Consider the type as Sized in the meanwhile to avoid
2398 // further errors. Delay our `bug` diagnostic here to get
2399 // emitted later as well in case we accidentally otherwise don't
2402 tcx.intern_type_list(&[tcx.types.err])
2407 fn sized_constraint_for_ty(&self,
2408 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2411 let result = match ty.sty {
2412 Bool | Char | Int(..) | Uint(..) | Float(..) |
2413 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2414 Array(..) | Closure(..) | Generator(..) | Never => {
2423 GeneratorWitness(..) => {
2424 // these are never sized - return the target type
2431 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2435 Adt(adt, substs) => {
2437 let adt_tys = adt.sized_constraint(tcx);
2438 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2441 .map(|ty| ty.subst(tcx, substs))
2442 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2446 Projection(..) | Opaque(..) => {
2447 // must calculate explicitly.
2448 // FIXME: consider special-casing always-Sized projections
2452 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2455 // perf hack: if there is a `T: Sized` bound, then
2456 // we know that `T` is Sized and do not need to check
2459 let sized_trait = match tcx.lang_items().sized_trait() {
2461 _ => return vec![ty]
2463 let sized_predicate = Binder::dummy(TraitRef {
2464 def_id: sized_trait,
2465 substs: tcx.mk_substs_trait(ty, &[])
2467 let predicates = &tcx.predicates_of(self.did).predicates;
2468 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2478 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2482 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2487 impl<'a, 'gcx, 'tcx> FieldDef {
2488 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2489 tcx.type_of(self.did).subst(tcx, subst)
2493 /// Represents the various closure traits in the Rust language. This
2494 /// will determine the type of the environment (`self`, in the
2495 /// desugaring) argument that the closure expects.
2497 /// You can get the environment type of a closure using
2498 /// `tcx.closure_env_ty()`.
2499 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2500 pub enum ClosureKind {
2501 // Warning: Ordering is significant here! The ordering is chosen
2502 // because the trait Fn is a subtrait of FnMut and so in turn, and
2503 // hence we order it so that Fn < FnMut < FnOnce.
2509 impl<'a, 'tcx> ClosureKind {
2510 // This is the initial value used when doing upvar inference.
2511 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2513 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2515 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2516 ClosureKind::FnMut => {
2517 tcx.require_lang_item(FnMutTraitLangItem)
2519 ClosureKind::FnOnce => {
2520 tcx.require_lang_item(FnOnceTraitLangItem)
2525 /// Returns `true` if this a type that impls this closure kind
2526 /// must also implement `other`.
2527 pub fn extends(self, other: ty::ClosureKind) -> bool {
2528 match (self, other) {
2529 (ClosureKind::Fn, ClosureKind::Fn) => true,
2530 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2531 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2532 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2533 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2534 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2539 /// Returns the representative scalar type for this closure kind.
2540 /// See `TyS::to_opt_closure_kind` for more details.
2541 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2543 ty::ClosureKind::Fn => tcx.types.i8,
2544 ty::ClosureKind::FnMut => tcx.types.i16,
2545 ty::ClosureKind::FnOnce => tcx.types.i32,
2550 impl<'tcx> TyS<'tcx> {
2551 /// Iterator that walks `self` and any types reachable from
2552 /// `self`, in depth-first order. Note that just walks the types
2553 /// that appear in `self`, it does not descend into the fields of
2554 /// structs or variants. For example:
2557 /// isize => { isize }
2558 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2559 /// [isize] => { [isize], isize }
2561 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2562 TypeWalker::new(self)
2565 /// Iterator that walks the immediate children of `self`. Hence
2566 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2567 /// (but not `i32`, like `walk`).
2568 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2569 walk::walk_shallow(self)
2572 /// Walks `ty` and any types appearing within `ty`, invoking the
2573 /// callback `f` on each type. If the callback returns false, then the
2574 /// children of the current type are ignored.
2576 /// Note: prefer `ty.walk()` where possible.
2577 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2578 where F: FnMut(Ty<'tcx>) -> bool
2580 let mut walker = self.walk();
2581 while let Some(ty) = walker.next() {
2583 walker.skip_current_subtree();
2590 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2592 hir::MutMutable => MutBorrow,
2593 hir::MutImmutable => ImmBorrow,
2597 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2598 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2599 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2601 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2603 MutBorrow => hir::MutMutable,
2604 ImmBorrow => hir::MutImmutable,
2606 // We have no type corresponding to a unique imm borrow, so
2607 // use `&mut`. It gives all the capabilities of an `&uniq`
2608 // and hence is a safe "over approximation".
2609 UniqueImmBorrow => hir::MutMutable,
2613 pub fn to_user_str(&self) -> &'static str {
2615 MutBorrow => "mutable",
2616 ImmBorrow => "immutable",
2617 UniqueImmBorrow => "uniquely immutable",
2622 #[derive(Debug, Clone)]
2623 pub enum Attributes<'gcx> {
2624 Owned(Lrc<[ast::Attribute]>),
2625 Borrowed(&'gcx [ast::Attribute])
2628 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2629 type Target = [ast::Attribute];
2631 fn deref(&self) -> &[ast::Attribute] {
2633 &Attributes::Owned(ref data) => &data,
2634 &Attributes::Borrowed(data) => data
2639 #[derive(Debug, PartialEq, Eq)]
2640 pub enum ImplOverlapKind {
2641 /// These impls are always allowed to overlap.
2643 /// These impls are allowed to overlap, but that raises
2644 /// an issue #33140 future-compatibility warning.
2646 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2647 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2649 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2650 /// that difference, making what reduces to the following set of impls:
2654 /// impl Trait for dyn Send + Sync {}
2655 /// impl Trait for dyn Sync + Send {}
2658 /// Obviously, once we made these types be identical, that code causes a coherence
2659 /// error and a fairly big headache for us. However, luckily for us, the trait
2660 /// `Trait` used in this case is basically a marker trait, and therefore having
2661 /// overlapping impls for it is sound.
2663 /// To handle this, we basically regard the trait as a marker trait, with an additional
2664 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2665 /// it has the following restrictions:
2667 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2669 /// 2. The trait-ref of both impls must be equal.
2670 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2672 /// 4. Neither of the impls can have any where-clauses.
2674 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2678 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2679 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2680 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2683 /// Returns an iterator of the def-ids for all body-owners in this
2684 /// crate. If you would prefer to iterate over the bodies
2685 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2688 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2692 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2695 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2696 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2697 f(self.hir().body_owner_def_id(body_id))
2701 pub fn expr_span(self, id: NodeId) -> Span {
2702 match self.hir().find(id) {
2703 Some(Node::Expr(e)) => {
2707 bug!("Node id {} is not an expr: {:?}", id, f);
2710 bug!("Node id {} is not present in the node map", id);
2715 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2716 self.associated_items(id)
2717 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2721 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2722 self.associated_items(did).any(|item| {
2723 item.relevant_for_never()
2727 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2728 let is_associated_item = if let Some(node_id) = self.hir().as_local_node_id(def_id) {
2729 match self.hir().get(node_id) {
2730 Node::TraitItem(_) | Node::ImplItem(_) => true,
2734 match self.describe_def(def_id).expect("no def for def-id") {
2735 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2740 if is_associated_item {
2741 Some(self.associated_item(def_id))
2747 fn associated_item_from_trait_item_ref(self,
2748 parent_def_id: DefId,
2749 parent_vis: &hir::Visibility,
2750 trait_item_ref: &hir::TraitItemRef)
2752 let def_id = self.hir().local_def_id(trait_item_ref.id.node_id);
2753 let (kind, has_self) = match trait_item_ref.kind {
2754 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2755 hir::AssociatedItemKind::Method { has_self } => {
2756 (ty::AssociatedKind::Method, has_self)
2758 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2759 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2763 ident: trait_item_ref.ident,
2765 // Visibility of trait items is inherited from their traits.
2766 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2767 defaultness: trait_item_ref.defaultness,
2769 container: TraitContainer(parent_def_id),
2770 method_has_self_argument: has_self
2774 fn associated_item_from_impl_item_ref(self,
2775 parent_def_id: DefId,
2776 impl_item_ref: &hir::ImplItemRef)
2778 let def_id = self.hir().local_def_id(impl_item_ref.id.node_id);
2779 let (kind, has_self) = match impl_item_ref.kind {
2780 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2781 hir::AssociatedItemKind::Method { has_self } => {
2782 (ty::AssociatedKind::Method, has_self)
2784 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2785 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2789 ident: impl_item_ref.ident,
2791 // Visibility of trait impl items doesn't matter.
2792 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2793 defaultness: impl_item_ref.defaultness,
2795 container: ImplContainer(parent_def_id),
2796 method_has_self_argument: has_self
2800 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2801 let hir_id = self.hir().node_to_hir_id(node_id);
2802 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2805 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2806 variant.fields.iter().position(|field| {
2807 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2811 pub fn associated_items(
2814 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2815 // Ideally, we would use `-> impl Iterator` here, but it falls
2816 // afoul of the conservative "capture [restrictions]" we put
2817 // in place, so we use a hand-written iterator.
2819 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2820 AssociatedItemsIterator {
2822 def_ids: self.associated_item_def_ids(def_id),
2827 /// Returns `true` if the impls are the same polarity and the trait either
2828 /// has no items or is annotated #[marker] and prevents item overrides.
2829 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2830 -> Option<ImplOverlapKind>
2832 let is_legit = if self.features().overlapping_marker_traits {
2833 let trait1_is_empty = self.impl_trait_ref(def_id1)
2834 .map_or(false, |trait_ref| {
2835 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2837 let trait2_is_empty = self.impl_trait_ref(def_id2)
2838 .map_or(false, |trait_ref| {
2839 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2841 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2845 let is_marker_impl = |def_id: DefId| -> bool {
2846 let trait_ref = self.impl_trait_ref(def_id);
2847 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2849 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2850 && is_marker_impl(def_id1)
2851 && is_marker_impl(def_id2)
2855 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
2857 Some(ImplOverlapKind::Permitted)
2859 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2860 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2861 if self_ty1 == self_ty2 {
2862 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2864 return Some(ImplOverlapKind::Issue33140);
2866 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2867 def_id1, def_id2, self_ty1, self_ty2);
2872 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2878 // Returns `ty::VariantDef` if `def` refers to a struct,
2879 // or variant or their constructors, panics otherwise.
2880 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2882 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2883 let enum_did = self.parent_def_id(did).unwrap();
2884 self.adt_def(enum_did).variant_with_id(did)
2886 Def::Struct(did) | Def::Union(did) => {
2887 self.adt_def(did).non_enum_variant()
2889 Def::StructCtor(ctor_did, ..) => {
2890 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2891 self.adt_def(did).non_enum_variant()
2893 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2897 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2898 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2899 let def_key = self.def_key(variant_def.did);
2900 match def_key.disambiguated_data.data {
2901 // for enum variants and tuple structs, the def-id of the ADT itself
2902 // is the *parent* of the variant
2903 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2904 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2906 // otherwise, for structs and unions, they share a def-id
2907 _ => variant_def.did,
2911 pub fn item_name(self, id: DefId) -> InternedString {
2912 if id.index == CRATE_DEF_INDEX {
2913 self.original_crate_name(id.krate).as_interned_str()
2915 let def_key = self.def_key(id);
2916 // The name of a StructCtor is that of its struct parent.
2917 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2918 self.item_name(DefId {
2920 index: def_key.parent.unwrap()
2923 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2924 bug!("item_name: no name for {:?}", self.def_path(id));
2930 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2931 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2935 ty::InstanceDef::Item(did) => {
2936 self.optimized_mir(did)
2938 ty::InstanceDef::VtableShim(..) |
2939 ty::InstanceDef::Intrinsic(..) |
2940 ty::InstanceDef::FnPtrShim(..) |
2941 ty::InstanceDef::Virtual(..) |
2942 ty::InstanceDef::ClosureOnceShim { .. } |
2943 ty::InstanceDef::DropGlue(..) |
2944 ty::InstanceDef::CloneShim(..) => {
2945 self.mir_shims(instance)
2950 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2951 /// Returns None if there is no MIR for the DefId
2952 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2953 if self.is_mir_available(did) {
2954 Some(self.optimized_mir(did))
2960 /// Get the attributes of a definition.
2961 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2962 if let Some(id) = self.hir().as_local_node_id(did) {
2963 Attributes::Borrowed(self.hir().attrs(id))
2965 Attributes::Owned(self.item_attrs(did))
2969 /// Determine whether an item is annotated with an attribute.
2970 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2971 attr::contains_name(&self.get_attrs(did), attr)
2974 /// Returns `true` if this is an `auto trait`.
2975 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2976 self.trait_def(trait_def_id).has_auto_impl
2979 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2980 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2983 /// Given the def-id of an impl, return the def_id of the trait it implements.
2984 /// If it implements no trait, return `None`.
2985 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2986 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2989 /// If the given defid describes a method belonging to an impl, return the
2990 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2991 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2992 let item = if def_id.krate != LOCAL_CRATE {
2993 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2994 Some(self.associated_item(def_id))
2999 self.opt_associated_item(def_id)
3002 item.and_then(|trait_item|
3003 match trait_item.container {
3004 TraitContainer(_) => None,
3005 ImplContainer(def_id) => Some(def_id),
3010 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3011 /// with the name of the crate containing the impl.
3012 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3013 if impl_did.is_local() {
3014 let node_id = self.hir().as_local_node_id(impl_did).unwrap();
3015 Ok(self.hir().span(node_id))
3017 Err(self.crate_name(impl_did.krate))
3021 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
3022 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3023 // definition's parent/scope to perform comparison.
3024 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3025 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
3028 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
3029 ident = ident.modern();
3030 let target_expansion = match scope.krate {
3031 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3034 let scope = match ident.span.adjust(target_expansion) {
3035 Some(actual_expansion) =>
3036 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3037 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
3038 None => self.hir().get_module_parent(block),
3044 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
3045 tcx: TyCtxt<'a, 'gcx, 'tcx>,
3046 def_ids: Lrc<Vec<DefId>>,
3050 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
3051 type Item = AssociatedItem;
3053 fn next(&mut self) -> Option<AssociatedItem> {
3054 let def_id = self.def_ids.get(self.next_index)?;
3055 self.next_index += 1;
3056 Some(self.tcx.associated_item(*def_id))
3060 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
3061 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
3062 F: FnOnce(&[hir::Freevar]) -> T,
3064 let def_id = self.hir().local_def_id(fid);
3065 match self.freevars(def_id) {
3072 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
3073 let id = tcx.hir().as_local_node_id(def_id).unwrap();
3074 let parent_id = tcx.hir().get_parent(id);
3075 let parent_def_id = tcx.hir().local_def_id(parent_id);
3076 let parent_item = tcx.hir().expect_item(parent_id);
3077 match parent_item.node {
3078 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3079 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
3080 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3082 debug_assert_eq!(assoc_item.def_id, def_id);
3087 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3088 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
3089 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3092 debug_assert_eq!(assoc_item.def_id, def_id);
3100 span_bug!(parent_item.span,
3101 "unexpected parent of trait or impl item or item not found: {:?}",
3105 /// Calculates the Sized-constraint.
3107 /// In fact, there are only a few options for the types in the constraint:
3108 /// - an obviously-unsized type
3109 /// - a type parameter or projection whose Sizedness can't be known
3110 /// - a tuple of type parameters or projections, if there are multiple
3112 /// - a Error, if a type contained itself. The representability
3113 /// check should catch this case.
3114 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3116 -> &'tcx [Ty<'tcx>] {
3117 let def = tcx.adt_def(def_id);
3119 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3122 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3125 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3130 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3132 -> Lrc<Vec<DefId>> {
3133 let id = tcx.hir().as_local_node_id(def_id).unwrap();
3134 let item = tcx.hir().expect_item(id);
3135 let vec: Vec<_> = match item.node {
3136 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3137 trait_item_refs.iter()
3138 .map(|trait_item_ref| trait_item_ref.id)
3139 .map(|id| tcx.hir().local_def_id(id.node_id))
3142 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3143 impl_item_refs.iter()
3144 .map(|impl_item_ref| impl_item_ref.id)
3145 .map(|id| tcx.hir().local_def_id(id.node_id))
3148 hir::ItemKind::TraitAlias(..) => vec![],
3149 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3154 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3155 tcx.hir().span_if_local(def_id).unwrap()
3158 /// If the given def ID describes an item belonging to a trait,
3159 /// return the ID of the trait that the trait item belongs to.
3160 /// Otherwise, return `None`.
3161 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3162 tcx.opt_associated_item(def_id)
3163 .and_then(|associated_item| {
3164 match associated_item.container {
3165 TraitContainer(def_id) => Some(def_id),
3166 ImplContainer(_) => None
3171 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3172 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3173 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
3174 if let Node::Item(item) = tcx.hir().get(node_id) {
3175 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3176 return exist_ty.impl_trait_fn;
3183 /// Returns `true` if `def_id` is a trait alias.
3184 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3185 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
3186 if let Node::Item(item) = tcx.hir().get(node_id) {
3187 if let hir::ItemKind::TraitAlias(..) = item.node {
3195 /// See `ParamEnv` struct definition for details.
3196 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3200 // The param_env of an impl Trait type is its defining function's param_env
3201 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3202 return param_env(tcx, parent);
3204 // Compute the bounds on Self and the type parameters.
3206 let InstantiatedPredicates { predicates } =
3207 tcx.predicates_of(def_id).instantiate_identity(tcx);
3209 // Finally, we have to normalize the bounds in the environment, in
3210 // case they contain any associated type projections. This process
3211 // can yield errors if the put in illegal associated types, like
3212 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3213 // report these errors right here; this doesn't actually feel
3214 // right to me, because constructing the environment feels like a
3215 // kind of a "idempotent" action, but I'm not sure where would be
3216 // a better place. In practice, we construct environments for
3217 // every fn once during type checking, and we'll abort if there
3218 // are any errors at that point, so after type checking you can be
3219 // sure that this will succeed without errors anyway.
3221 let unnormalized_env = ty::ParamEnv::new(
3222 tcx.intern_predicates(&predicates),
3223 traits::Reveal::UserFacing,
3224 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3227 let body_id = tcx.hir().as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3228 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3230 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3231 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3234 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3235 crate_num: CrateNum) -> CrateDisambiguator {
3236 assert_eq!(crate_num, LOCAL_CRATE);
3237 tcx.sess.local_crate_disambiguator()
3240 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3241 crate_num: CrateNum) -> Symbol {
3242 assert_eq!(crate_num, LOCAL_CRATE);
3243 tcx.crate_name.clone()
3246 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3247 crate_num: CrateNum)
3249 assert_eq!(crate_num, LOCAL_CRATE);
3250 tcx.hir().crate_hash
3253 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3254 instance_def: InstanceDef<'tcx>)
3256 match instance_def {
3257 InstanceDef::Item(..) |
3258 InstanceDef::DropGlue(..) => {
3259 let mir = tcx.instance_mir(instance_def);
3260 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3262 // Estimate the size of other compiler-generated shims to be 1.
3267 /// If `def_id` is an issue 33140 hack impl, return its self type. Otherwise
3270 /// See ImplOverlapKind::Issue33140 for more details.
3271 fn issue33140_self_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3275 debug!("issue33140_self_ty({:?})", def_id);
3277 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3278 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3281 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3283 let is_marker_like =
3284 tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
3285 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3287 // Check whether these impls would be ok for a marker trait.
3288 if !is_marker_like {
3289 debug!("issue33140_self_ty - not marker-like!");
3293 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3294 if trait_ref.substs.len() != 1 {
3295 debug!("issue33140_self_ty - impl has substs!");
3299 let predicates = tcx.predicates_of(def_id);
3300 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3301 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3305 let self_ty = trait_ref.self_ty();
3306 let self_ty_matches = match self_ty.sty {
3307 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3311 if self_ty_matches {
3312 debug!("issue33140_self_ty - MATCHES!");
3315 debug!("issue33140_self_ty - non-matching self type");
3320 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3321 context::provide(providers);
3322 erase_regions::provide(providers);
3323 layout::provide(providers);
3324 util::provide(providers);
3325 constness::provide(providers);
3326 *providers = ty::query::Providers {
3328 associated_item_def_ids,
3329 adt_sized_constraint,
3333 crate_disambiguator,
3334 original_crate_name,
3336 trait_impls_of: trait_def::trait_impls_of_provider,
3337 instance_def_size_estimate,
3343 /// A map for the local crate mapping each type to a vector of its
3344 /// inherent impls. This is not meant to be used outside of coherence;
3345 /// rather, you should request the vector for a specific type via
3346 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3347 /// (constructing this map requires touching the entire crate).
3348 #[derive(Clone, Debug, Default)]
3349 pub struct CrateInherentImpls {
3350 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3353 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3354 pub struct SymbolName {
3355 // FIXME: we don't rely on interning or equality here - better have
3356 // this be a `&'tcx str`.
3357 pub name: InternedString
3360 impl_stable_hash_for!(struct self::SymbolName {
3365 pub fn new(name: &str) -> SymbolName {
3367 name: Symbol::intern(name).as_interned_str()
3371 pub fn as_str(&self) -> LocalInternedString {
3376 impl fmt::Display for SymbolName {
3377 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3378 fmt::Display::fmt(&self.name, fmt)
3382 impl fmt::Debug for SymbolName {
3383 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3384 fmt::Display::fmt(&self.name, fmt)