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 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
593 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
595 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
598 /// A dummy type used to force List to by unsized without requiring fat pointers
599 type OpaqueListContents;
602 /// A wrapper for slices with the additional invariant
603 /// that the slice is interned and no other slice with
604 /// the same contents can exist in the same context.
605 /// This means we can use pointer for both
606 /// equality comparisons and hashing.
607 /// Note: `Slice` was already taken by the `Ty`.
612 opaque: OpaqueListContents,
615 unsafe impl<T: Sync> Sync for List<T> {}
617 impl<T: Copy> List<T> {
619 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
620 assert!(!mem::needs_drop::<T>());
621 assert!(mem::size_of::<T>() != 0);
622 assert!(slice.len() != 0);
624 // Align up the size of the len (usize) field
625 let align = mem::align_of::<T>();
626 let align_mask = align - 1;
627 let offset = mem::size_of::<usize>();
628 let offset = (offset + align_mask) & !align_mask;
630 let size = offset + slice.len() * mem::size_of::<T>();
632 let mem = arena.alloc_raw(
634 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
636 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
638 result.len = slice.len();
640 // Write the elements
641 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
642 arena_slice.copy_from_slice(slice);
649 impl<T: fmt::Debug> fmt::Debug for List<T> {
650 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
655 impl<T: Encodable> Encodable for List<T> {
657 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
662 impl<T> Ord for List<T> where T: Ord {
663 fn cmp(&self, other: &List<T>) -> Ordering {
664 if self == other { Ordering::Equal } else {
665 <[T] as Ord>::cmp(&**self, &**other)
670 impl<T> PartialOrd for List<T> where T: PartialOrd {
671 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
672 if self == other { Some(Ordering::Equal) } else {
673 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
678 impl<T: PartialEq> PartialEq for List<T> {
680 fn eq(&self, other: &List<T>) -> bool {
684 impl<T: Eq> Eq for List<T> {}
686 impl<T> Hash for List<T> {
688 fn hash<H: Hasher>(&self, s: &mut H) {
689 (self as *const List<T>).hash(s)
693 impl<T> Deref for List<T> {
696 fn deref(&self) -> &[T] {
698 slice::from_raw_parts(self.data.as_ptr(), self.len)
703 impl<'a, T> IntoIterator for &'a List<T> {
705 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
707 fn into_iter(self) -> Self::IntoIter {
712 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
716 pub fn empty<'a>() -> &'a List<T> {
717 #[repr(align(64), C)]
718 struct EmptySlice([u8; 64]);
719 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
720 assert!(mem::align_of::<T>() <= 64);
722 &*(&EMPTY_SLICE as *const _ as *const List<T>)
727 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
728 pub struct UpvarPath {
729 pub hir_id: hir::HirId,
732 /// Upvars do not get their own node-id. Instead, we use the pair of
733 /// the original var id (that is, the root variable that is referenced
734 /// by the upvar) and the id of the closure expression.
735 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
737 pub var_path: UpvarPath,
738 pub closure_expr_id: LocalDefId,
741 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
742 pub enum BorrowKind {
743 /// Data must be immutable and is aliasable.
746 /// Data must be immutable but not aliasable. This kind of borrow
747 /// cannot currently be expressed by the user and is used only in
748 /// implicit closure bindings. It is needed when the closure
749 /// is borrowing or mutating a mutable referent, e.g.:
751 /// let x: &mut isize = ...;
752 /// let y = || *x += 5;
754 /// If we were to try to translate this closure into a more explicit
755 /// form, we'd encounter an error with the code as written:
757 /// struct Env { x: & &mut isize }
758 /// let x: &mut isize = ...;
759 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
760 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
762 /// This is then illegal because you cannot mutate a `&mut` found
763 /// in an aliasable location. To solve, you'd have to translate with
764 /// an `&mut` borrow:
766 /// struct Env { x: & &mut isize }
767 /// let x: &mut isize = ...;
768 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
769 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
771 /// Now the assignment to `**env.x` is legal, but creating a
772 /// mutable pointer to `x` is not because `x` is not mutable. We
773 /// could fix this by declaring `x` as `let mut x`. This is ok in
774 /// user code, if awkward, but extra weird for closures, since the
775 /// borrow is hidden.
777 /// So we introduce a "unique imm" borrow -- the referent is
778 /// immutable, but not aliasable. This solves the problem. For
779 /// simplicity, we don't give users the way to express this
780 /// borrow, it's just used when translating closures.
783 /// Data is mutable and not aliasable.
787 /// Information describing the capture of an upvar. This is computed
788 /// during `typeck`, specifically by `regionck`.
789 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
790 pub enum UpvarCapture<'tcx> {
791 /// Upvar is captured by value. This is always true when the
792 /// closure is labeled `move`, but can also be true in other cases
793 /// depending on inference.
796 /// Upvar is captured by reference.
797 ByRef(UpvarBorrow<'tcx>),
800 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
801 pub struct UpvarBorrow<'tcx> {
802 /// The kind of borrow: by-ref upvars have access to shared
803 /// immutable borrows, which are not part of the normal language
805 pub kind: BorrowKind,
807 /// Region of the resulting reference.
808 pub region: ty::Region<'tcx>,
811 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
813 #[derive(Copy, Clone)]
814 pub struct ClosureUpvar<'tcx> {
820 #[derive(Clone, Copy, PartialEq, Eq)]
821 pub enum IntVarValue {
823 UintType(ast::UintTy),
826 #[derive(Clone, Copy, PartialEq, Eq)]
827 pub struct FloatVarValue(pub ast::FloatTy);
829 impl ty::EarlyBoundRegion {
830 pub fn to_bound_region(&self) -> ty::BoundRegion {
831 ty::BoundRegion::BrNamed(self.def_id, self.name)
834 /// Does this early bound region have a name? Early bound regions normally
835 /// always have names except when using anonymous lifetimes (`'_`).
836 pub fn has_name(&self) -> bool {
837 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
841 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
842 pub enum GenericParamDefKind {
846 object_lifetime_default: ObjectLifetimeDefault,
847 synthetic: Option<hir::SyntheticTyParamKind>,
851 #[derive(Clone, RustcEncodable, RustcDecodable)]
852 pub struct GenericParamDef {
853 pub name: InternedString,
857 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
858 /// on generic parameter `'a`/`T`, asserts data behind the parameter
859 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
860 pub pure_wrt_drop: bool,
862 pub kind: GenericParamDefKind,
865 impl GenericParamDef {
866 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
867 if let GenericParamDefKind::Lifetime = self.kind {
868 ty::EarlyBoundRegion {
874 bug!("cannot convert a non-lifetime parameter def to an early bound region")
878 pub fn to_bound_region(&self) -> ty::BoundRegion {
879 if let GenericParamDefKind::Lifetime = self.kind {
880 self.to_early_bound_region_data().to_bound_region()
882 bug!("cannot convert a non-lifetime parameter def to an early bound region")
888 pub struct GenericParamCount {
889 pub lifetimes: usize,
893 /// Information about the formal type/lifetime parameters associated
894 /// with an item or method. Analogous to `hir::Generics`.
896 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
897 /// `Self` (optionally), `Lifetime` params..., `Type` params...
898 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
899 pub struct Generics {
900 pub parent: Option<DefId>,
901 pub parent_count: usize,
902 pub params: Vec<GenericParamDef>,
904 /// Reverse map to the `index` field of each `GenericParamDef`
905 pub param_def_id_to_index: FxHashMap<DefId, u32>,
908 pub has_late_bound_regions: Option<Span>,
911 impl<'a, 'gcx, 'tcx> Generics {
912 pub fn count(&self) -> usize {
913 self.parent_count + self.params.len()
916 pub fn own_counts(&self) -> GenericParamCount {
917 // We could cache this as a property of `GenericParamCount`, but
918 // the aim is to refactor this away entirely eventually and the
919 // presence of this method will be a constant reminder.
920 let mut own_counts: GenericParamCount = Default::default();
922 for param in &self.params {
924 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
925 GenericParamDefKind::Type { .. } => own_counts.types += 1,
932 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
933 for param in &self.params {
935 GenericParamDefKind::Type { .. } => return true,
936 GenericParamDefKind::Lifetime => {}
939 if let Some(parent_def_id) = self.parent {
940 let parent = tcx.generics_of(parent_def_id);
941 parent.requires_monomorphization(tcx)
947 pub fn region_param(&'tcx self,
948 param: &EarlyBoundRegion,
949 tcx: TyCtxt<'a, 'gcx, 'tcx>)
950 -> &'tcx GenericParamDef
952 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
953 let param = &self.params[index as usize];
955 ty::GenericParamDefKind::Lifetime => param,
956 _ => bug!("expected lifetime parameter, but found another generic parameter")
959 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
960 .region_param(param, tcx)
964 /// Returns the `GenericParamDef` associated with this `ParamTy`.
965 pub fn type_param(&'tcx self,
967 tcx: TyCtxt<'a, 'gcx, 'tcx>)
968 -> &'tcx GenericParamDef {
969 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
970 let param = &self.params[index as usize];
972 ty::GenericParamDefKind::Type {..} => param,
973 _ => bug!("expected type parameter, but found another generic parameter")
976 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
977 .type_param(param, tcx)
982 /// Bounds on generics.
983 #[derive(Clone, Default)]
984 pub struct GenericPredicates<'tcx> {
985 pub parent: Option<DefId>,
986 pub predicates: Vec<(Predicate<'tcx>, Span)>,
989 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
990 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
992 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
993 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
994 -> InstantiatedPredicates<'tcx> {
995 let mut instantiated = InstantiatedPredicates::empty();
996 self.instantiate_into(tcx, &mut instantiated, substs);
1000 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1001 -> InstantiatedPredicates<'tcx> {
1002 InstantiatedPredicates {
1003 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1007 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1008 instantiated: &mut InstantiatedPredicates<'tcx>,
1009 substs: &Substs<'tcx>) {
1010 if let Some(def_id) = self.parent {
1011 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1013 instantiated.predicates.extend(
1014 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1018 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1019 -> InstantiatedPredicates<'tcx> {
1020 let mut instantiated = InstantiatedPredicates::empty();
1021 self.instantiate_identity_into(tcx, &mut instantiated);
1025 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1026 instantiated: &mut InstantiatedPredicates<'tcx>) {
1027 if let Some(def_id) = self.parent {
1028 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1030 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1033 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1034 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1035 -> InstantiatedPredicates<'tcx>
1037 assert_eq!(self.parent, None);
1038 InstantiatedPredicates {
1039 predicates: self.predicates.iter().map(|(pred, _)| {
1040 pred.subst_supertrait(tcx, poly_trait_ref)
1046 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1047 pub enum Predicate<'tcx> {
1048 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1049 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1050 /// would be the type parameters.
1051 Trait(PolyTraitPredicate<'tcx>),
1054 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1057 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1059 /// where `<T as TraitRef>::Name == X`, approximately.
1060 /// See the `ProjectionPredicate` struct for details.
1061 Projection(PolyProjectionPredicate<'tcx>),
1063 /// no syntax: `T` well-formed
1064 WellFormed(Ty<'tcx>),
1066 /// trait must be object-safe
1069 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1070 /// for some substitutions `...` and `T` being a closure type.
1071 /// Satisfied (or refuted) once we know the closure's kind.
1072 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1075 Subtype(PolySubtypePredicate<'tcx>),
1077 /// Constant initializer must evaluate successfully.
1078 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1081 /// The crate outlives map is computed during typeck and contains the
1082 /// outlives of every item in the local crate. You should not use it
1083 /// directly, because to do so will make your pass dependent on the
1084 /// HIR of every item in the local crate. Instead, use
1085 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1087 pub struct CratePredicatesMap<'tcx> {
1088 /// For each struct with outlive bounds, maps to a vector of the
1089 /// predicate of its outlive bounds. If an item has no outlives
1090 /// bounds, it will have no entry.
1091 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1093 /// An empty vector, useful for cloning.
1094 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1097 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1098 fn as_ref(&self) -> &Predicate<'tcx> {
1103 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1104 /// Performs a substitution suitable for going from a
1105 /// poly-trait-ref to supertraits that must hold if that
1106 /// poly-trait-ref holds. This is slightly different from a normal
1107 /// substitution in terms of what happens with bound regions. See
1108 /// lengthy comment below for details.
1109 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1110 trait_ref: &ty::PolyTraitRef<'tcx>)
1111 -> ty::Predicate<'tcx>
1113 // The interaction between HRTB and supertraits is not entirely
1114 // obvious. Let me walk you (and myself) through an example.
1116 // Let's start with an easy case. Consider two traits:
1118 // trait Foo<'a>: Bar<'a,'a> { }
1119 // trait Bar<'b,'c> { }
1121 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1122 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1123 // knew that `Foo<'x>` (for any 'x) then we also know that
1124 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1125 // normal substitution.
1127 // In terms of why this is sound, the idea is that whenever there
1128 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1129 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1130 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1133 // Another example to be careful of is this:
1135 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1136 // trait Bar1<'b,'c> { }
1138 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1139 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1140 // reason is similar to the previous example: any impl of
1141 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1142 // basically we would want to collapse the bound lifetimes from
1143 // the input (`trait_ref`) and the supertraits.
1145 // To achieve this in practice is fairly straightforward. Let's
1146 // consider the more complicated scenario:
1148 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1149 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1150 // where both `'x` and `'b` would have a DB index of 1.
1151 // The substitution from the input trait-ref is therefore going to be
1152 // `'a => 'x` (where `'x` has a DB index of 1).
1153 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1154 // early-bound parameter and `'b' is a late-bound parameter with a
1156 // - If we replace `'a` with `'x` from the input, it too will have
1157 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1158 // just as we wanted.
1160 // There is only one catch. If we just apply the substitution `'a
1161 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1162 // adjust the DB index because we substituting into a binder (it
1163 // tries to be so smart...) resulting in `for<'x> for<'b>
1164 // Bar1<'x,'b>` (we have no syntax for this, so use your
1165 // imagination). Basically the 'x will have DB index of 2 and 'b
1166 // will have DB index of 1. Not quite what we want. So we apply
1167 // the substitution to the *contents* of the trait reference,
1168 // rather than the trait reference itself (put another way, the
1169 // substitution code expects equal binding levels in the values
1170 // from the substitution and the value being substituted into, and
1171 // this trick achieves that).
1173 let substs = &trait_ref.skip_binder().substs;
1175 Predicate::Trait(ref binder) =>
1176 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1177 Predicate::Subtype(ref binder) =>
1178 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1179 Predicate::RegionOutlives(ref binder) =>
1180 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1181 Predicate::TypeOutlives(ref binder) =>
1182 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1183 Predicate::Projection(ref binder) =>
1184 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1185 Predicate::WellFormed(data) =>
1186 Predicate::WellFormed(data.subst(tcx, substs)),
1187 Predicate::ObjectSafe(trait_def_id) =>
1188 Predicate::ObjectSafe(trait_def_id),
1189 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1190 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1191 Predicate::ConstEvaluatable(def_id, const_substs) =>
1192 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1197 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1198 pub struct TraitPredicate<'tcx> {
1199 pub trait_ref: TraitRef<'tcx>
1202 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1204 impl<'tcx> TraitPredicate<'tcx> {
1205 pub fn def_id(&self) -> DefId {
1206 self.trait_ref.def_id
1209 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1210 self.trait_ref.input_types()
1213 pub fn self_ty(&self) -> Ty<'tcx> {
1214 self.trait_ref.self_ty()
1218 impl<'tcx> PolyTraitPredicate<'tcx> {
1219 pub fn def_id(&self) -> DefId {
1220 // ok to skip binder since trait def-id does not care about regions
1221 self.skip_binder().def_id()
1225 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1226 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1227 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1228 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1230 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1232 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1233 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1235 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1236 pub struct SubtypePredicate<'tcx> {
1237 pub a_is_expected: bool,
1241 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1243 /// This kind of predicate has no *direct* correspondent in the
1244 /// syntax, but it roughly corresponds to the syntactic forms:
1246 /// 1. `T: TraitRef<..., Item=Type>`
1247 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1249 /// In particular, form #1 is "desugared" to the combination of a
1250 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1251 /// predicates. Form #2 is a broader form in that it also permits
1252 /// equality between arbitrary types. Processing an instance of
1253 /// Form #2 eventually yields one of these `ProjectionPredicate`
1254 /// instances to normalize the LHS.
1255 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1256 pub struct ProjectionPredicate<'tcx> {
1257 pub projection_ty: ProjectionTy<'tcx>,
1261 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1263 impl<'tcx> PolyProjectionPredicate<'tcx> {
1264 /// Returns the `DefId` of the associated item being projected.
1265 pub fn item_def_id(&self) -> DefId {
1266 self.skip_binder().projection_ty.item_def_id
1270 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1271 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1272 // `self.0.trait_ref` is permitted to have escaping regions.
1273 // This is because here `self` has a `Binder` and so does our
1274 // return value, so we are preserving the number of binding
1276 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1279 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1280 self.map_bound(|predicate| predicate.ty)
1283 /// The `DefId` of the `TraitItem` for the associated type.
1285 /// Note that this is not the `DefId` of the `TraitRef` containing this
1286 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1287 pub fn projection_def_id(&self) -> DefId {
1288 // okay to skip binder since trait def-id does not care about regions
1289 self.skip_binder().projection_ty.item_def_id
1293 pub trait ToPolyTraitRef<'tcx> {
1294 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1297 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1298 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1299 ty::Binder::dummy(self.clone())
1303 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1304 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1305 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1309 pub trait ToPredicate<'tcx> {
1310 fn to_predicate(&self) -> Predicate<'tcx>;
1313 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1314 fn to_predicate(&self) -> Predicate<'tcx> {
1315 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1316 trait_ref: self.clone()
1321 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1322 fn to_predicate(&self) -> Predicate<'tcx> {
1323 ty::Predicate::Trait(self.to_poly_trait_predicate())
1327 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1328 fn to_predicate(&self) -> Predicate<'tcx> {
1329 Predicate::RegionOutlives(self.clone())
1333 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1334 fn to_predicate(&self) -> Predicate<'tcx> {
1335 Predicate::TypeOutlives(self.clone())
1339 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1340 fn to_predicate(&self) -> Predicate<'tcx> {
1341 Predicate::Projection(self.clone())
1345 // A custom iterator used by Predicate::walk_tys.
1346 enum WalkTysIter<'tcx, I, J, K>
1347 where I: Iterator<Item = Ty<'tcx>>,
1348 J: Iterator<Item = Ty<'tcx>>,
1349 K: Iterator<Item = Ty<'tcx>>
1353 Two(Ty<'tcx>, Ty<'tcx>),
1359 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1360 where I: Iterator<Item = Ty<'tcx>>,
1361 J: Iterator<Item = Ty<'tcx>>,
1362 K: Iterator<Item = Ty<'tcx>>
1364 type Item = Ty<'tcx>;
1366 fn next(&mut self) -> Option<Ty<'tcx>> {
1368 WalkTysIter::None => None,
1369 WalkTysIter::One(item) => {
1370 *self = WalkTysIter::None;
1373 WalkTysIter::Two(item1, item2) => {
1374 *self = WalkTysIter::One(item2);
1377 WalkTysIter::Types(ref mut iter) => {
1380 WalkTysIter::InputTypes(ref mut iter) => {
1383 WalkTysIter::ProjectionTypes(ref mut iter) => {
1390 impl<'tcx> Predicate<'tcx> {
1391 /// Iterates over the types in this predicate. Note that in all
1392 /// cases this is skipping over a binder, so late-bound regions
1393 /// with depth 0 are bound by the predicate.
1394 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1396 ty::Predicate::Trait(ref data) => {
1397 WalkTysIter::InputTypes(data.skip_binder().input_types())
1399 ty::Predicate::Subtype(binder) => {
1400 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1401 WalkTysIter::Two(a, b)
1403 ty::Predicate::TypeOutlives(binder) => {
1404 WalkTysIter::One(binder.skip_binder().0)
1406 ty::Predicate::RegionOutlives(..) => {
1409 ty::Predicate::Projection(ref data) => {
1410 let inner = data.skip_binder();
1411 WalkTysIter::ProjectionTypes(
1412 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1414 ty::Predicate::WellFormed(data) => {
1415 WalkTysIter::One(data)
1417 ty::Predicate::ObjectSafe(_trait_def_id) => {
1420 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1421 WalkTysIter::Types(closure_substs.substs.types())
1423 ty::Predicate::ConstEvaluatable(_, substs) => {
1424 WalkTysIter::Types(substs.types())
1429 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1431 Predicate::Trait(ref t) => {
1432 Some(t.to_poly_trait_ref())
1434 Predicate::Projection(..) |
1435 Predicate::Subtype(..) |
1436 Predicate::RegionOutlives(..) |
1437 Predicate::WellFormed(..) |
1438 Predicate::ObjectSafe(..) |
1439 Predicate::ClosureKind(..) |
1440 Predicate::TypeOutlives(..) |
1441 Predicate::ConstEvaluatable(..) => {
1447 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1449 Predicate::TypeOutlives(data) => {
1452 Predicate::Trait(..) |
1453 Predicate::Projection(..) |
1454 Predicate::Subtype(..) |
1455 Predicate::RegionOutlives(..) |
1456 Predicate::WellFormed(..) |
1457 Predicate::ObjectSafe(..) |
1458 Predicate::ClosureKind(..) |
1459 Predicate::ConstEvaluatable(..) => {
1466 /// Represents the bounds declared on a particular set of type
1467 /// parameters. Should eventually be generalized into a flag list of
1468 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1469 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1470 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1471 /// the `GenericPredicates` are expressed in terms of the bound type
1472 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1473 /// represented a set of bounds for some particular instantiation,
1474 /// meaning that the generic parameters have been substituted with
1479 /// struct Foo<T,U:Bar<T>> { ... }
1481 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1482 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1483 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1484 /// [usize:Bar<isize>]]`.
1486 pub struct InstantiatedPredicates<'tcx> {
1487 pub predicates: Vec<Predicate<'tcx>>,
1490 impl<'tcx> InstantiatedPredicates<'tcx> {
1491 pub fn empty() -> InstantiatedPredicates<'tcx> {
1492 InstantiatedPredicates { predicates: vec![] }
1495 pub fn is_empty(&self) -> bool {
1496 self.predicates.is_empty()
1500 /// "Universes" are used during type- and trait-checking in the
1501 /// presence of `for<..>` binders to control what sets of names are
1502 /// visible. Universes are arranged into a tree: the root universe
1503 /// contains names that are always visible. Each child then adds a new
1504 /// set of names that are visible, in addition to those of its parent.
1505 /// We say that the child universe "extends" the parent universe with
1508 /// To make this more concrete, consider this program:
1512 /// fn bar<T>(x: T) {
1513 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1517 /// The struct name `Foo` is in the root universe U0. But the type
1518 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1519 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1520 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1521 /// region `'a` is in a universe U2 that extends U1, because we can
1522 /// name it inside the fn type but not outside.
1524 /// Universes are used to do type- and trait-checking around these
1525 /// "forall" binders (also called **universal quantification**). The
1526 /// idea is that when, in the body of `bar`, we refer to `T` as a
1527 /// type, we aren't referring to any type in particular, but rather a
1528 /// kind of "fresh" type that is distinct from all other types we have
1529 /// actually declared. This is called a **placeholder** type, and we
1530 /// use universes to talk about this. In other words, a type name in
1531 /// universe 0 always corresponds to some "ground" type that the user
1532 /// declared, but a type name in a non-zero universe is a placeholder
1533 /// type -- an idealized representative of "types in general" that we
1534 /// use for checking generic functions.
1536 pub struct UniverseIndex {
1537 DEBUG_FORMAT = "U{}",
1541 impl_stable_hash_for!(struct UniverseIndex { private });
1543 impl UniverseIndex {
1544 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1546 /// Returns the "next" universe index in order -- this new index
1547 /// is considered to extend all previous universes. This
1548 /// corresponds to entering a `forall` quantifier. So, for
1549 /// example, suppose we have this type in universe `U`:
1552 /// for<'a> fn(&'a u32)
1555 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1556 /// new universe that extends `U` -- in this new universe, we can
1557 /// name the region `'a`, but that region was not nameable from
1558 /// `U` because it was not in scope there.
1559 pub fn next_universe(self) -> UniverseIndex {
1560 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1563 /// Returns `true` if `self` can name a name from `other` -- in other words,
1564 /// if the set of names in `self` is a superset of those in
1565 /// `other` (`self >= other`).
1566 pub fn can_name(self, other: UniverseIndex) -> bool {
1567 self.private >= other.private
1570 /// Returns `true` if `self` cannot name some names from `other` -- in other
1571 /// words, if the set of names in `self` is a strict subset of
1572 /// those in `other` (`self < other`).
1573 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1574 self.private < other.private
1578 /// The "placeholder index" fully defines a placeholder region.
1579 /// Placeholder regions are identified by both a **universe** as well
1580 /// as a "bound-region" within that universe. The `bound_region` is
1581 /// basically a name -- distinct bound regions within the same
1582 /// universe are just two regions with an unknown relationship to one
1584 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1585 pub struct Placeholder<T> {
1586 pub universe: UniverseIndex,
1590 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1591 where T: HashStable<StableHashingContext<'a>>
1593 fn hash_stable<W: StableHasherResult>(
1595 hcx: &mut StableHashingContext<'a>,
1596 hasher: &mut StableHasher<W>
1598 self.universe.hash_stable(hcx, hasher);
1599 self.name.hash_stable(hcx, hasher);
1603 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1605 pub type PlaceholderType = Placeholder<BoundVar>;
1607 /// When type checking, we use the `ParamEnv` to track
1608 /// details about the set of where-clauses that are in scope at this
1609 /// particular point.
1610 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1611 pub struct ParamEnv<'tcx> {
1612 /// Obligations that the caller must satisfy. This is basically
1613 /// the set of bounds on the in-scope type parameters, translated
1614 /// into Obligations, and elaborated and normalized.
1615 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1617 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1618 /// want `Reveal::All` -- note that this is always paired with an
1619 /// empty environment. To get that, use `ParamEnv::reveal()`.
1620 pub reveal: traits::Reveal,
1622 /// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
1623 /// register that `def_id` (useful for transitioning to the chalk trait
1625 pub def_id: Option<DefId>,
1628 impl<'tcx> ParamEnv<'tcx> {
1629 /// Construct a trait environment suitable for contexts where
1630 /// there are no where clauses in scope. Hidden types (like `impl
1631 /// Trait`) are left hidden, so this is suitable for ordinary
1634 pub fn empty() -> Self {
1635 Self::new(List::empty(), Reveal::UserFacing, None)
1638 /// Construct a trait environment with no where clauses in scope
1639 /// where the values of all `impl Trait` and other hidden types
1640 /// are revealed. This is suitable for monomorphized, post-typeck
1641 /// environments like codegen or doing optimizations.
1643 /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
1644 /// or invoke `param_env.with_reveal_all()`.
1646 pub fn reveal_all() -> Self {
1647 Self::new(List::empty(), Reveal::All, None)
1650 /// Construct a trait environment with the given set of predicates.
1653 caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1655 def_id: Option<DefId>
1657 ty::ParamEnv { caller_bounds, reveal, def_id }
1660 /// Returns a new parameter environment with the same clauses, but
1661 /// which "reveals" the true results of projections in all cases
1662 /// (even for associated types that are specializable). This is
1663 /// the desired behavior during codegen and certain other special
1664 /// contexts; normally though we want to use `Reveal::UserFacing`,
1665 /// which is the default.
1666 pub fn with_reveal_all(self) -> Self {
1667 ty::ParamEnv { reveal: Reveal::All, ..self }
1670 /// Returns this same environment but with no caller bounds.
1671 pub fn without_caller_bounds(self) -> Self {
1672 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1675 /// Creates a suitable environment in which to perform trait
1676 /// queries on the given value. When type-checking, this is simply
1677 /// the pair of the environment plus value. But when reveal is set to
1678 /// All, then if `value` does not reference any type parameters, we will
1679 /// pair it with the empty environment. This improves caching and is generally
1682 /// N.B., we preserve the environment when type-checking because it
1683 /// is possible for the user to have wacky where-clauses like
1684 /// `where Box<u32>: Copy`, which are clearly never
1685 /// satisfiable. We generally want to behave as if they were true,
1686 /// although the surrounding function is never reachable.
1687 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1689 Reveal::UserFacing => {
1697 if value.has_placeholders()
1698 || value.needs_infer()
1699 || value.has_param_types()
1700 || value.has_self_ty()
1708 param_env: self.without_caller_bounds(),
1717 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1718 pub struct ParamEnvAnd<'tcx, T> {
1719 pub param_env: ParamEnv<'tcx>,
1723 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1724 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1725 (self.param_env, self.value)
1729 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1730 where T: HashStable<StableHashingContext<'a>>
1732 fn hash_stable<W: StableHasherResult>(&self,
1733 hcx: &mut StableHashingContext<'a>,
1734 hasher: &mut StableHasher<W>) {
1740 param_env.hash_stable(hcx, hasher);
1741 value.hash_stable(hcx, hasher);
1745 #[derive(Copy, Clone, Debug)]
1746 pub struct Destructor {
1747 /// The def-id of the destructor method
1752 pub struct AdtFlags: u32 {
1753 const NO_ADT_FLAGS = 0;
1754 const IS_ENUM = 1 << 0;
1755 const IS_UNION = 1 << 1;
1756 const IS_STRUCT = 1 << 2;
1757 const HAS_CTOR = 1 << 3;
1758 const IS_PHANTOM_DATA = 1 << 4;
1759 const IS_FUNDAMENTAL = 1 << 5;
1760 const IS_BOX = 1 << 6;
1761 /// Indicates whether the type is an `Arc`.
1762 const IS_ARC = 1 << 7;
1763 /// Indicates whether the type is an `Rc`.
1764 const IS_RC = 1 << 8;
1765 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1766 /// (i.e., this flag is never set unless this ADT is an enum).
1767 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 9;
1772 pub struct VariantFlags: u32 {
1773 const NO_VARIANT_FLAGS = 0;
1774 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1775 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1780 pub struct VariantDef {
1781 /// The variant's `DefId`. If this is a tuple-like struct,
1782 /// this is the `DefId` of the struct's ctor.
1784 pub ident: Ident, // struct's name if this is a struct
1785 pub discr: VariantDiscr,
1786 pub fields: Vec<FieldDef>,
1787 pub ctor_kind: CtorKind,
1788 flags: VariantFlags,
1791 impl<'a, 'gcx, 'tcx> VariantDef {
1792 /// Create a new `VariantDef`.
1794 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1795 /// and for everything else, it is the variant DefId.
1796 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1797 /// this is the struct DefId for structs, and the variant DefId for variants.
1799 /// Note that we *could* use the constructor DefId, because the constructor attributes
1800 /// redirect to the base attributes, but compiling a small crate requires
1801 /// loading the AdtDefs for all the structs in the universe (e.g., coherence for any
1802 /// built-in trait), and we do not want to load attributes twice.
1804 /// If someone speeds up attribute loading to not be a performance concern, they can
1805 /// remove this hack and use the constructor DefId everywhere.
1806 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1809 discr: VariantDiscr,
1810 fields: Vec<FieldDef>,
1812 ctor_kind: CtorKind,
1813 attribute_def_id: DefId)
1816 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, ident, discr,
1817 fields, adt_kind, ctor_kind, attribute_def_id);
1818 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1819 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1820 debug!("found non-exhaustive field list for {:?}", did);
1821 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1834 pub fn is_field_list_non_exhaustive(&self) -> bool {
1835 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1839 impl_stable_hash_for!(struct VariantDef {
1841 ident -> (ident.name),
1848 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1849 pub enum VariantDiscr {
1850 /// Explicit value for this variant, i.e., `X = 123`.
1851 /// The `DefId` corresponds to the embedded constant.
1854 /// The previous variant's discriminant plus one.
1855 /// For efficiency reasons, the distance from the
1856 /// last `Explicit` discriminant is being stored,
1857 /// or `0` for the first variant, if it has none.
1862 pub struct FieldDef {
1865 pub vis: Visibility,
1868 /// The definition of an abstract data type -- a struct or enum.
1870 /// These are all interned (by `intern_adt_def`) into the `adt_defs`
1874 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1876 pub repr: ReprOptions,
1879 impl PartialOrd for AdtDef {
1880 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1881 Some(self.cmp(&other))
1885 /// There should be only one AdtDef for each `did`, therefore
1886 /// it is fine to implement `Ord` only based on `did`.
1887 impl Ord for AdtDef {
1888 fn cmp(&self, other: &AdtDef) -> Ordering {
1889 self.did.cmp(&other.did)
1893 impl PartialEq for AdtDef {
1894 // AdtDef are always interned and this is part of TyS equality
1896 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1899 impl Eq for AdtDef {}
1901 impl Hash for AdtDef {
1903 fn hash<H: Hasher>(&self, s: &mut H) {
1904 (self as *const AdtDef).hash(s)
1908 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1909 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1914 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1917 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1918 fn hash_stable<W: StableHasherResult>(&self,
1919 hcx: &mut StableHashingContext<'a>,
1920 hasher: &mut StableHasher<W>) {
1922 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1925 let hash: Fingerprint = CACHE.with(|cache| {
1926 let addr = self as *const AdtDef as usize;
1927 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1935 let mut hasher = StableHasher::new();
1936 did.hash_stable(hcx, &mut hasher);
1937 variants.hash_stable(hcx, &mut hasher);
1938 flags.hash_stable(hcx, &mut hasher);
1939 repr.hash_stable(hcx, &mut hasher);
1945 hash.hash_stable(hcx, hasher);
1949 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1950 pub enum AdtKind { Struct, Union, Enum }
1952 impl Into<DataTypeKind> for AdtKind {
1953 fn into(self) -> DataTypeKind {
1955 AdtKind::Struct => DataTypeKind::Struct,
1956 AdtKind::Union => DataTypeKind::Union,
1957 AdtKind::Enum => DataTypeKind::Enum,
1963 #[derive(RustcEncodable, RustcDecodable, Default)]
1964 pub struct ReprFlags: u8 {
1965 const IS_C = 1 << 0;
1966 const IS_SIMD = 1 << 1;
1967 const IS_TRANSPARENT = 1 << 2;
1968 // Internal only for now. If true, don't reorder fields.
1969 const IS_LINEAR = 1 << 3;
1971 // Any of these flags being set prevent field reordering optimisation.
1972 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1973 ReprFlags::IS_SIMD.bits |
1974 ReprFlags::IS_LINEAR.bits;
1978 impl_stable_hash_for!(struct ReprFlags {
1982 /// Represents the repr options provided by the user,
1983 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1984 pub struct ReprOptions {
1985 pub int: Option<attr::IntType>,
1988 pub flags: ReprFlags,
1991 impl_stable_hash_for!(struct ReprOptions {
1999 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
2000 let mut flags = ReprFlags::empty();
2001 let mut size = None;
2002 let mut max_align = 0;
2003 let mut min_pack = 0;
2004 for attr in tcx.get_attrs(did).iter() {
2005 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2006 flags.insert(match r {
2007 attr::ReprC => ReprFlags::IS_C,
2008 attr::ReprPacked(pack) => {
2009 min_pack = if min_pack > 0 {
2010 cmp::min(pack, min_pack)
2016 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2017 attr::ReprSimd => ReprFlags::IS_SIMD,
2018 attr::ReprInt(i) => {
2022 attr::ReprAlign(align) => {
2023 max_align = cmp::max(align, max_align);
2030 // This is here instead of layout because the choice must make it into metadata.
2031 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
2032 flags.insert(ReprFlags::IS_LINEAR);
2034 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2038 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2040 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2042 pub fn packed(&self) -> bool { self.pack > 0 }
2044 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2046 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2048 pub fn discr_type(&self) -> attr::IntType {
2049 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2052 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2053 /// layout" optimizations, such as representing `Foo<&T>` as a
2055 pub fn inhibit_enum_layout_opt(&self) -> bool {
2056 self.c() || self.int.is_some()
2059 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2060 /// optimizations, such as with repr(C), repr(packed(1)), or repr(<int>).
2061 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2062 self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
2066 /// Returns true if this `#[repr()]` should inhibit union abi optimisations
2067 pub fn inhibit_union_abi_opt(&self) -> bool {
2073 impl<'a, 'gcx, 'tcx> AdtDef {
2074 fn new(tcx: TyCtxt<'_, '_, '_>,
2077 variants: IndexVec<VariantIdx, VariantDef>,
2078 repr: ReprOptions) -> Self {
2079 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2080 let mut flags = AdtFlags::NO_ADT_FLAGS;
2082 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2083 debug!("found non-exhaustive variant list for {:?}", did);
2084 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2086 flags |= match kind {
2087 AdtKind::Enum => AdtFlags::IS_ENUM,
2088 AdtKind::Union => AdtFlags::IS_UNION,
2089 AdtKind::Struct => AdtFlags::IS_STRUCT,
2092 if let AdtKind::Struct = kind {
2093 let variant_def = &variants[VariantIdx::new(0)];
2094 let def_key = tcx.def_key(variant_def.did);
2095 match def_key.disambiguated_data.data {
2096 DefPathData::StructCtor => flags |= AdtFlags::HAS_CTOR,
2101 let attrs = tcx.get_attrs(did);
2102 if attr::contains_name(&attrs, "fundamental") {
2103 flags |= AdtFlags::IS_FUNDAMENTAL;
2105 if Some(did) == tcx.lang_items().phantom_data() {
2106 flags |= AdtFlags::IS_PHANTOM_DATA;
2108 if Some(did) == tcx.lang_items().owned_box() {
2109 flags |= AdtFlags::IS_BOX;
2111 if Some(did) == tcx.lang_items().arc() {
2112 flags |= AdtFlags::IS_ARC;
2114 if Some(did) == tcx.lang_items().rc() {
2115 flags |= AdtFlags::IS_RC;
2127 pub fn is_struct(&self) -> bool {
2128 self.flags.contains(AdtFlags::IS_STRUCT)
2132 pub fn is_union(&self) -> bool {
2133 self.flags.contains(AdtFlags::IS_UNION)
2137 pub fn is_enum(&self) -> bool {
2138 self.flags.contains(AdtFlags::IS_ENUM)
2142 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2143 self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2146 /// Returns the kind of the ADT.
2148 pub fn adt_kind(&self) -> AdtKind {
2151 } else if self.is_union() {
2158 pub fn descr(&self) -> &'static str {
2159 match self.adt_kind() {
2160 AdtKind::Struct => "struct",
2161 AdtKind::Union => "union",
2162 AdtKind::Enum => "enum",
2167 pub fn variant_descr(&self) -> &'static str {
2168 match self.adt_kind() {
2169 AdtKind::Struct => "struct",
2170 AdtKind::Union => "union",
2171 AdtKind::Enum => "variant",
2175 /// If this function returns `true`, it implies that `is_struct` must return `true`.
2177 pub fn has_ctor(&self) -> bool {
2178 self.flags.contains(AdtFlags::HAS_CTOR)
2181 /// Returns whether this type is `#[fundamental]` for the purposes
2182 /// of coherence checking.
2184 pub fn is_fundamental(&self) -> bool {
2185 self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
2188 /// Returns `true` if this is PhantomData<T>.
2190 pub fn is_phantom_data(&self) -> bool {
2191 self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
2194 /// Returns `true` if this is `Arc<T>`.
2195 pub fn is_arc(&self) -> bool {
2196 self.flags.contains(AdtFlags::IS_ARC)
2199 /// Returns `true` if this is `Rc<T>`.
2200 pub fn is_rc(&self) -> bool {
2201 self.flags.contains(AdtFlags::IS_RC)
2204 /// Returns `true` if this is Box<T>.
2206 pub fn is_box(&self) -> bool {
2207 self.flags.contains(AdtFlags::IS_BOX)
2210 /// Returns whether this type has a destructor.
2211 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2212 self.destructor(tcx).is_some()
2215 /// Asserts this is a struct or union and returns its unique variant.
2216 pub fn non_enum_variant(&self) -> &VariantDef {
2217 assert!(self.is_struct() || self.is_union());
2218 &self.variants[VariantIdx::new(0)]
2222 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2223 tcx.predicates_of(self.did)
2226 /// Returns an iterator over all fields contained
2229 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2230 self.variants.iter().flat_map(|v| v.fields.iter())
2233 pub fn is_payloadfree(&self) -> bool {
2234 !self.variants.is_empty() &&
2235 self.variants.iter().all(|v| v.fields.is_empty())
2238 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2241 .find(|v| v.did == vid)
2242 .expect("variant_with_id: unknown variant")
2245 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2248 .find(|(_, v)| v.did == vid)
2249 .expect("variant_index_with_id: unknown variant")
2253 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2255 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2256 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2257 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2258 Def::SelfCtor(..) => self.non_enum_variant(),
2259 _ => bug!("unexpected def {:?} in variant_of_def", def)
2264 pub fn eval_explicit_discr(
2266 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2268 ) -> Option<Discr<'tcx>> {
2269 let param_env = ParamEnv::empty();
2270 let repr_type = self.repr.discr_type();
2271 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2272 let instance = ty::Instance::new(expr_did, substs);
2273 let cid = GlobalId {
2277 match tcx.const_eval(param_env.and(cid)) {
2279 // FIXME: Find the right type and use it instead of `val.ty` here
2280 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2281 trace!("discriminants: {} ({:?})", b, repr_type);
2287 info!("invalid enum discriminant: {:#?}", val);
2288 ::mir::interpret::struct_error(
2289 tcx.at(tcx.def_span(expr_did)),
2290 "constant evaluation of enum discriminant resulted in non-integer",
2295 Err(ErrorHandled::Reported) => {
2296 if !expr_did.is_local() {
2297 span_bug!(tcx.def_span(expr_did),
2298 "variant discriminant evaluation succeeded \
2299 in its crate but failed locally");
2303 Err(ErrorHandled::TooGeneric) => span_bug!(
2304 tcx.def_span(expr_did),
2305 "enum discriminant depends on generic arguments",
2311 pub fn discriminants(
2313 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2314 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2315 let repr_type = self.repr.discr_type();
2316 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2317 let mut prev_discr = None::<Discr<'tcx>>;
2318 self.variants.iter_enumerated().map(move |(i, v)| {
2319 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2320 if let VariantDiscr::Explicit(expr_did) = v.discr {
2321 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2325 prev_discr = Some(discr);
2331 /// Compute the discriminant value used by a specific variant.
2332 /// Unlike `discriminants`, this is (amortized) constant-time,
2333 /// only doing at most one query for evaluating an explicit
2334 /// discriminant (the last one before the requested variant),
2335 /// assuming there are no constant-evaluation errors there.
2336 pub fn discriminant_for_variant(&self,
2337 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2338 variant_index: VariantIdx)
2340 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2341 let explicit_value = val
2342 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2343 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2344 explicit_value.checked_add(tcx, offset as u128).0
2347 /// Yields a DefId for the discriminant and an offset to add to it
2348 /// Alternatively, if there is no explicit discriminant, returns the
2349 /// inferred discriminant directly
2350 pub fn discriminant_def_for_variant(
2352 variant_index: VariantIdx,
2353 ) -> (Option<DefId>, u32) {
2354 let mut explicit_index = variant_index.as_u32();
2357 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2358 ty::VariantDiscr::Relative(0) => {
2362 ty::VariantDiscr::Relative(distance) => {
2363 explicit_index -= distance;
2365 ty::VariantDiscr::Explicit(did) => {
2366 expr_did = Some(did);
2371 (expr_did, variant_index.as_u32() - explicit_index)
2374 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2375 tcx.adt_destructor(self.did)
2378 /// Returns a list of types such that `Self: Sized` if and only
2379 /// if that type is Sized, or `TyErr` if this type is recursive.
2381 /// Oddly enough, checking that the sized-constraint is Sized is
2382 /// actually more expressive than checking all members:
2383 /// the Sized trait is inductive, so an associated type that references
2384 /// Self would prevent its containing ADT from being Sized.
2386 /// Due to normalization being eager, this applies even if
2387 /// the associated type is behind a pointer, e.g., issue #31299.
2388 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2389 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2392 debug!("adt_sized_constraint: {:?} is recursive", self);
2393 // This should be reported as an error by `check_representable`.
2395 // Consider the type as Sized in the meanwhile to avoid
2396 // further errors. Delay our `bug` diagnostic here to get
2397 // emitted later as well in case we accidentally otherwise don't
2400 tcx.intern_type_list(&[tcx.types.err])
2405 fn sized_constraint_for_ty(&self,
2406 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2409 let result = match ty.sty {
2410 Bool | Char | Int(..) | Uint(..) | Float(..) |
2411 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2412 Array(..) | Closure(..) | Generator(..) | Never => {
2421 GeneratorWitness(..) => {
2422 // these are never sized - return the target type
2429 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2433 Adt(adt, substs) => {
2435 let adt_tys = adt.sized_constraint(tcx);
2436 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2439 .map(|ty| ty.subst(tcx, substs))
2440 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2444 Projection(..) | Opaque(..) => {
2445 // must calculate explicitly.
2446 // FIXME: consider special-casing always-Sized projections
2450 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2453 // perf hack: if there is a `T: Sized` bound, then
2454 // we know that `T` is Sized and do not need to check
2457 let sized_trait = match tcx.lang_items().sized_trait() {
2459 _ => return vec![ty]
2461 let sized_predicate = Binder::dummy(TraitRef {
2462 def_id: sized_trait,
2463 substs: tcx.mk_substs_trait(ty, &[])
2465 let predicates = &tcx.predicates_of(self.did).predicates;
2466 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2476 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2480 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2485 impl<'a, 'gcx, 'tcx> FieldDef {
2486 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2487 tcx.type_of(self.did).subst(tcx, subst)
2491 /// Represents the various closure traits in the Rust language. This
2492 /// will determine the type of the environment (`self`, in the
2493 /// desugaring) argument that the closure expects.
2495 /// You can get the environment type of a closure using
2496 /// `tcx.closure_env_ty()`.
2497 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2498 pub enum ClosureKind {
2499 // Warning: Ordering is significant here! The ordering is chosen
2500 // because the trait Fn is a subtrait of FnMut and so in turn, and
2501 // hence we order it so that Fn < FnMut < FnOnce.
2507 impl<'a, 'tcx> ClosureKind {
2508 // This is the initial value used when doing upvar inference.
2509 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2511 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2513 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2514 ClosureKind::FnMut => {
2515 tcx.require_lang_item(FnMutTraitLangItem)
2517 ClosureKind::FnOnce => {
2518 tcx.require_lang_item(FnOnceTraitLangItem)
2523 /// Returns `true` if this a type that impls this closure kind
2524 /// must also implement `other`.
2525 pub fn extends(self, other: ty::ClosureKind) -> bool {
2526 match (self, other) {
2527 (ClosureKind::Fn, ClosureKind::Fn) => true,
2528 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2529 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2530 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2531 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2532 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2537 /// Returns the representative scalar type for this closure kind.
2538 /// See `TyS::to_opt_closure_kind` for more details.
2539 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2541 ty::ClosureKind::Fn => tcx.types.i8,
2542 ty::ClosureKind::FnMut => tcx.types.i16,
2543 ty::ClosureKind::FnOnce => tcx.types.i32,
2548 impl<'tcx> TyS<'tcx> {
2549 /// Iterator that walks `self` and any types reachable from
2550 /// `self`, in depth-first order. Note that just walks the types
2551 /// that appear in `self`, it does not descend into the fields of
2552 /// structs or variants. For example:
2555 /// isize => { isize }
2556 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2557 /// [isize] => { [isize], isize }
2559 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2560 TypeWalker::new(self)
2563 /// Iterator that walks the immediate children of `self`. Hence
2564 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2565 /// (but not `i32`, like `walk`).
2566 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2567 walk::walk_shallow(self)
2570 /// Walks `ty` and any types appearing within `ty`, invoking the
2571 /// callback `f` on each type. If the callback returns false, then the
2572 /// children of the current type are ignored.
2574 /// Note: prefer `ty.walk()` where possible.
2575 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2576 where F: FnMut(Ty<'tcx>) -> bool
2578 let mut walker = self.walk();
2579 while let Some(ty) = walker.next() {
2581 walker.skip_current_subtree();
2588 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2590 hir::MutMutable => MutBorrow,
2591 hir::MutImmutable => ImmBorrow,
2595 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2596 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2597 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2599 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2601 MutBorrow => hir::MutMutable,
2602 ImmBorrow => hir::MutImmutable,
2604 // We have no type corresponding to a unique imm borrow, so
2605 // use `&mut`. It gives all the capabilities of an `&uniq`
2606 // and hence is a safe "over approximation".
2607 UniqueImmBorrow => hir::MutMutable,
2611 pub fn to_user_str(&self) -> &'static str {
2613 MutBorrow => "mutable",
2614 ImmBorrow => "immutable",
2615 UniqueImmBorrow => "uniquely immutable",
2620 #[derive(Debug, Clone)]
2621 pub enum Attributes<'gcx> {
2622 Owned(Lrc<[ast::Attribute]>),
2623 Borrowed(&'gcx [ast::Attribute])
2626 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2627 type Target = [ast::Attribute];
2629 fn deref(&self) -> &[ast::Attribute] {
2631 &Attributes::Owned(ref data) => &data,
2632 &Attributes::Borrowed(data) => data
2637 #[derive(Debug, PartialEq, Eq)]
2638 pub enum ImplOverlapKind {
2639 /// These impls are always allowed to overlap.
2641 /// These impls are allowed to overlap, but that raises
2642 /// an issue #33140 future-compatibility warning.
2644 /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
2645 /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
2647 /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
2648 /// that difference, making what reduces to the following set of impls:
2652 /// impl Trait for dyn Send + Sync {}
2653 /// impl Trait for dyn Sync + Send {}
2656 /// Obviously, once we made these types be identical, that code causes a coherence
2657 /// error and a fairly big headache for us. However, luckily for us, the trait
2658 /// `Trait` used in this case is basically a marker trait, and therefore having
2659 /// overlapping impls for it is sound.
2661 /// To handle this, we basically regard the trait as a marker trait, with an additional
2662 /// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
2663 /// it has the following restrictions:
2665 /// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
2667 /// 2. The trait-ref of both impls must be equal.
2668 /// 3. The trait-ref of both impls must be a trait object type consisting only of
2670 /// 4. Neither of the impls can have any where-clauses.
2672 /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
2676 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2677 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2678 self.typeck_tables_of(self.hir().body_owner_def_id(body))
2681 /// Returns an iterator of the def-ids for all body-owners in this
2682 /// crate. If you would prefer to iterate over the bodies
2683 /// themselves, you can do `self.hir().krate().body_ids.iter()`.
2686 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2690 .map(move |&body_id| self.hir().body_owner_def_id(body_id))
2693 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2694 par_iter(&self.hir().krate().body_ids).for_each(|&body_id| {
2695 f(self.hir().body_owner_def_id(body_id))
2699 pub fn expr_span(self, id: NodeId) -> Span {
2700 match self.hir().find(id) {
2701 Some(Node::Expr(e)) => {
2705 bug!("Node id {} is not an expr: {:?}", id, f);
2708 bug!("Node id {} is not present in the node map", id);
2713 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2714 self.associated_items(id)
2715 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2719 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2720 self.associated_items(did).any(|item| {
2721 item.relevant_for_never()
2725 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2726 let is_associated_item = if let Some(node_id) = self.hir().as_local_node_id(def_id) {
2727 match self.hir().get(node_id) {
2728 Node::TraitItem(_) | Node::ImplItem(_) => true,
2732 match self.describe_def(def_id).expect("no def for def-id") {
2733 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2738 if is_associated_item {
2739 Some(self.associated_item(def_id))
2745 fn associated_item_from_trait_item_ref(self,
2746 parent_def_id: DefId,
2747 parent_vis: &hir::Visibility,
2748 trait_item_ref: &hir::TraitItemRef)
2750 let def_id = self.hir().local_def_id(trait_item_ref.id.node_id);
2751 let (kind, has_self) = match trait_item_ref.kind {
2752 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2753 hir::AssociatedItemKind::Method { has_self } => {
2754 (ty::AssociatedKind::Method, has_self)
2756 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2757 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2761 ident: trait_item_ref.ident,
2763 // Visibility of trait items is inherited from their traits.
2764 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2765 defaultness: trait_item_ref.defaultness,
2767 container: TraitContainer(parent_def_id),
2768 method_has_self_argument: has_self
2772 fn associated_item_from_impl_item_ref(self,
2773 parent_def_id: DefId,
2774 impl_item_ref: &hir::ImplItemRef)
2776 let def_id = self.hir().local_def_id(impl_item_ref.id.node_id);
2777 let (kind, has_self) = match impl_item_ref.kind {
2778 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2779 hir::AssociatedItemKind::Method { has_self } => {
2780 (ty::AssociatedKind::Method, has_self)
2782 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2783 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2787 ident: impl_item_ref.ident,
2789 // Visibility of trait impl items doesn't matter.
2790 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2791 defaultness: impl_item_ref.defaultness,
2793 container: ImplContainer(parent_def_id),
2794 method_has_self_argument: has_self
2798 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2799 let hir_id = self.hir().node_to_hir_id(node_id);
2800 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2803 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2804 variant.fields.iter().position(|field| {
2805 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2809 pub fn associated_items(
2812 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2813 // Ideally, we would use `-> impl Iterator` here, but it falls
2814 // afoul of the conservative "capture [restrictions]" we put
2815 // in place, so we use a hand-written iterator.
2817 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2818 AssociatedItemsIterator {
2820 def_ids: self.associated_item_def_ids(def_id),
2825 /// Returns `true` if the impls are the same polarity and the trait either
2826 /// has no items or is annotated #[marker] and prevents item overrides.
2827 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId)
2828 -> Option<ImplOverlapKind>
2830 let is_legit = if self.features().overlapping_marker_traits {
2831 let trait1_is_empty = self.impl_trait_ref(def_id1)
2832 .map_or(false, |trait_ref| {
2833 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2835 let trait2_is_empty = self.impl_trait_ref(def_id2)
2836 .map_or(false, |trait_ref| {
2837 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2839 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2843 let is_marker_impl = |def_id: DefId| -> bool {
2844 let trait_ref = self.impl_trait_ref(def_id);
2845 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2847 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2848 && is_marker_impl(def_id1)
2849 && is_marker_impl(def_id2)
2853 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted)",
2855 Some(ImplOverlapKind::Permitted)
2857 if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
2858 if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
2859 if self_ty1 == self_ty2 {
2860 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
2862 return Some(ImplOverlapKind::Issue33140);
2864 debug!("impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
2865 def_id1, def_id2, self_ty1, self_ty2);
2870 debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None",
2876 // Returns `ty::VariantDef` if `def` refers to a struct,
2877 // or variant or their constructors, panics otherwise.
2878 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2880 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2881 let enum_did = self.parent_def_id(did).unwrap();
2882 self.adt_def(enum_did).variant_with_id(did)
2884 Def::Struct(did) | Def::Union(did) => {
2885 self.adt_def(did).non_enum_variant()
2887 Def::StructCtor(ctor_did, ..) => {
2888 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2889 self.adt_def(did).non_enum_variant()
2891 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2895 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2896 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2897 let def_key = self.def_key(variant_def.did);
2898 match def_key.disambiguated_data.data {
2899 // for enum variants and tuple structs, the def-id of the ADT itself
2900 // is the *parent* of the variant
2901 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2902 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2904 // otherwise, for structs and unions, they share a def-id
2905 _ => variant_def.did,
2909 pub fn item_name(self, id: DefId) -> InternedString {
2910 if id.index == CRATE_DEF_INDEX {
2911 self.original_crate_name(id.krate).as_interned_str()
2913 let def_key = self.def_key(id);
2914 // The name of a StructCtor is that of its struct parent.
2915 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2916 self.item_name(DefId {
2918 index: def_key.parent.unwrap()
2921 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2922 bug!("item_name: no name for {:?}", self.def_path(id));
2928 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2929 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2933 ty::InstanceDef::Item(did) => {
2934 self.optimized_mir(did)
2936 ty::InstanceDef::VtableShim(..) |
2937 ty::InstanceDef::Intrinsic(..) |
2938 ty::InstanceDef::FnPtrShim(..) |
2939 ty::InstanceDef::Virtual(..) |
2940 ty::InstanceDef::ClosureOnceShim { .. } |
2941 ty::InstanceDef::DropGlue(..) |
2942 ty::InstanceDef::CloneShim(..) => {
2943 self.mir_shims(instance)
2948 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2949 /// Returns None if there is no MIR for the DefId
2950 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2951 if self.is_mir_available(did) {
2952 Some(self.optimized_mir(did))
2958 /// Get the attributes of a definition.
2959 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2960 if let Some(id) = self.hir().as_local_node_id(did) {
2961 Attributes::Borrowed(self.hir().attrs(id))
2963 Attributes::Owned(self.item_attrs(did))
2967 /// Determine whether an item is annotated with an attribute.
2968 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2969 attr::contains_name(&self.get_attrs(did), attr)
2972 /// Returns `true` if this is an `auto trait`.
2973 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2974 self.trait_def(trait_def_id).has_auto_impl
2977 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2978 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2981 /// Given the def-id of an impl, return the def_id of the trait it implements.
2982 /// If it implements no trait, return `None`.
2983 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2984 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2987 /// If the given defid describes a method belonging to an impl, return the
2988 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2989 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2990 let item = if def_id.krate != LOCAL_CRATE {
2991 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2992 Some(self.associated_item(def_id))
2997 self.opt_associated_item(def_id)
3000 item.and_then(|trait_item|
3001 match trait_item.container {
3002 TraitContainer(_) => None,
3003 ImplContainer(def_id) => Some(def_id),
3008 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
3009 /// with the name of the crate containing the impl.
3010 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
3011 if impl_did.is_local() {
3012 let node_id = self.hir().as_local_node_id(impl_did).unwrap();
3013 Ok(self.hir().span(node_id))
3015 Err(self.crate_name(impl_did.krate))
3019 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
3020 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
3021 // definition's parent/scope to perform comparison.
3022 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
3023 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
3026 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
3027 ident = ident.modern();
3028 let target_expansion = match scope.krate {
3029 LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
3032 let scope = match ident.span.adjust(target_expansion) {
3033 Some(actual_expansion) =>
3034 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
3035 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
3036 None => self.hir().get_module_parent(block),
3042 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
3043 tcx: TyCtxt<'a, 'gcx, 'tcx>,
3044 def_ids: Lrc<Vec<DefId>>,
3048 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
3049 type Item = AssociatedItem;
3051 fn next(&mut self) -> Option<AssociatedItem> {
3052 let def_id = self.def_ids.get(self.next_index)?;
3053 self.next_index += 1;
3054 Some(self.tcx.associated_item(*def_id))
3058 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
3059 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
3060 F: FnOnce(&[hir::Freevar]) -> T,
3062 let def_id = self.hir().local_def_id(fid);
3063 match self.freevars(def_id) {
3070 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
3071 let id = tcx.hir().as_local_node_id(def_id).unwrap();
3072 let parent_id = tcx.hir().get_parent(id);
3073 let parent_def_id = tcx.hir().local_def_id(parent_id);
3074 let parent_item = tcx.hir().expect_item(parent_id);
3075 match parent_item.node {
3076 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3077 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
3078 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
3080 debug_assert_eq!(assoc_item.def_id, def_id);
3085 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3086 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
3087 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3090 debug_assert_eq!(assoc_item.def_id, def_id);
3098 span_bug!(parent_item.span,
3099 "unexpected parent of trait or impl item or item not found: {:?}",
3103 /// Calculates the Sized-constraint.
3105 /// In fact, there are only a few options for the types in the constraint:
3106 /// - an obviously-unsized type
3107 /// - a type parameter or projection whose Sizedness can't be known
3108 /// - a tuple of type parameters or projections, if there are multiple
3110 /// - a Error, if a type contained itself. The representability
3111 /// check should catch this case.
3112 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3114 -> &'tcx [Ty<'tcx>] {
3115 let def = tcx.adt_def(def_id);
3117 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3120 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3123 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3128 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3130 -> Lrc<Vec<DefId>> {
3131 let id = tcx.hir().as_local_node_id(def_id).unwrap();
3132 let item = tcx.hir().expect_item(id);
3133 let vec: Vec<_> = match item.node {
3134 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3135 trait_item_refs.iter()
3136 .map(|trait_item_ref| trait_item_ref.id)
3137 .map(|id| tcx.hir().local_def_id(id.node_id))
3140 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3141 impl_item_refs.iter()
3142 .map(|impl_item_ref| impl_item_ref.id)
3143 .map(|id| tcx.hir().local_def_id(id.node_id))
3146 hir::ItemKind::TraitAlias(..) => vec![],
3147 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3152 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3153 tcx.hir().span_if_local(def_id).unwrap()
3156 /// If the given def ID describes an item belonging to a trait,
3157 /// return the ID of the trait that the trait item belongs to.
3158 /// Otherwise, return `None`.
3159 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3160 tcx.opt_associated_item(def_id)
3161 .and_then(|associated_item| {
3162 match associated_item.container {
3163 TraitContainer(def_id) => Some(def_id),
3164 ImplContainer(_) => None
3169 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3170 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3171 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
3172 if let Node::Item(item) = tcx.hir().get(node_id) {
3173 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3174 return exist_ty.impl_trait_fn;
3181 /// Returns `true` if `def_id` is a trait alias.
3182 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3183 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
3184 if let Node::Item(item) = tcx.hir().get(node_id) {
3185 if let hir::ItemKind::TraitAlias(..) = item.node {
3193 /// See `ParamEnv` struct definition for details.
3194 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3198 // The param_env of an impl Trait type is its defining function's param_env
3199 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3200 return param_env(tcx, parent);
3202 // Compute the bounds on Self and the type parameters.
3204 let InstantiatedPredicates { predicates } =
3205 tcx.predicates_of(def_id).instantiate_identity(tcx);
3207 // Finally, we have to normalize the bounds in the environment, in
3208 // case they contain any associated type projections. This process
3209 // can yield errors if the put in illegal associated types, like
3210 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3211 // report these errors right here; this doesn't actually feel
3212 // right to me, because constructing the environment feels like a
3213 // kind of a "idempotent" action, but I'm not sure where would be
3214 // a better place. In practice, we construct environments for
3215 // every fn once during type checking, and we'll abort if there
3216 // are any errors at that point, so after type checking you can be
3217 // sure that this will succeed without errors anyway.
3219 let unnormalized_env = ty::ParamEnv::new(
3220 tcx.intern_predicates(&predicates),
3221 traits::Reveal::UserFacing,
3222 if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
3225 let body_id = tcx.hir().as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3226 tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3228 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3229 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3232 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3233 crate_num: CrateNum) -> CrateDisambiguator {
3234 assert_eq!(crate_num, LOCAL_CRATE);
3235 tcx.sess.local_crate_disambiguator()
3238 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3239 crate_num: CrateNum) -> Symbol {
3240 assert_eq!(crate_num, LOCAL_CRATE);
3241 tcx.crate_name.clone()
3244 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3245 crate_num: CrateNum)
3247 assert_eq!(crate_num, LOCAL_CRATE);
3248 tcx.hir().crate_hash
3251 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3252 instance_def: InstanceDef<'tcx>)
3254 match instance_def {
3255 InstanceDef::Item(..) |
3256 InstanceDef::DropGlue(..) => {
3257 let mir = tcx.instance_mir(instance_def);
3258 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3260 // Estimate the size of other compiler-generated shims to be 1.
3265 /// If `def_id` is an issue 33140 hack impl, return its self type. Otherwise
3268 /// See ImplOverlapKind::Issue33140 for more details.
3269 fn issue33140_self_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3273 debug!("issue33140_self_ty({:?})", def_id);
3275 let trait_ref = tcx.impl_trait_ref(def_id).unwrap_or_else(|| {
3276 bug!("issue33140_self_ty called on inherent impl {:?}", def_id)
3279 debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
3281 let is_marker_like =
3282 tcx.impl_polarity(def_id) == hir::ImplPolarity::Positive &&
3283 tcx.associated_item_def_ids(trait_ref.def_id).is_empty();
3285 // Check whether these impls would be ok for a marker trait.
3286 if !is_marker_like {
3287 debug!("issue33140_self_ty - not marker-like!");
3291 // impl must be `impl Trait for dyn Marker1 + Marker2 + ...`
3292 if trait_ref.substs.len() != 1 {
3293 debug!("issue33140_self_ty - impl has substs!");
3297 let predicates = tcx.predicates_of(def_id);
3298 if predicates.parent.is_some() || !predicates.predicates.is_empty() {
3299 debug!("issue33140_self_ty - impl has predicates {:?}!", predicates);
3303 let self_ty = trait_ref.self_ty();
3304 let self_ty_matches = match self_ty.sty {
3305 ty::Dynamic(ref data, ty::ReStatic) => data.principal().is_none(),
3309 if self_ty_matches {
3310 debug!("issue33140_self_ty - MATCHES!");
3313 debug!("issue33140_self_ty - non-matching self type");
3318 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3319 context::provide(providers);
3320 erase_regions::provide(providers);
3321 layout::provide(providers);
3322 util::provide(providers);
3323 constness::provide(providers);
3324 *providers = ty::query::Providers {
3326 associated_item_def_ids,
3327 adt_sized_constraint,
3331 crate_disambiguator,
3332 original_crate_name,
3334 trait_impls_of: trait_def::trait_impls_of_provider,
3335 instance_def_size_estimate,
3341 /// A map for the local crate mapping each type to a vector of its
3342 /// inherent impls. This is not meant to be used outside of coherence;
3343 /// rather, you should request the vector for a specific type via
3344 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3345 /// (constructing this map requires touching the entire crate).
3346 #[derive(Clone, Debug, Default)]
3347 pub struct CrateInherentImpls {
3348 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3351 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3352 pub struct SymbolName {
3353 // FIXME: we don't rely on interning or equality here - better have
3354 // this be a `&'tcx str`.
3355 pub name: InternedString
3358 impl_stable_hash_for!(struct self::SymbolName {
3363 pub fn new(name: &str) -> SymbolName {
3365 name: Symbol::intern(name).as_interned_str()
3369 pub fn as_str(&self) -> LocalInternedString {
3374 impl fmt::Display for SymbolName {
3375 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3376 fmt::Display::fmt(&self.name, fmt)
3380 impl fmt::Debug for SymbolName {
3381 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3382 fmt::Display::fmt(&self.name, fmt)