1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 pub use self::Variance::*;
12 pub use self::AssociatedItemContainer::*;
13 pub use self::BorrowKind::*;
14 pub use self::IntVarValue::*;
15 pub use self::fold::TypeFoldable;
17 use hir::{map as hir_map, FreevarMap, TraitMap};
19 use hir::def::{Def, CtorKind, ExportMap};
20 use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
21 use hir::map::DefPathData;
22 use rustc_data_structures::svh::Svh;
24 use ich::StableHashingContext;
25 use infer::canonical::Canonical;
26 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
27 use middle::privacy::AccessLevels;
28 use middle::resolve_lifetime::ObjectLifetimeDefault;
30 use mir::interpret::{GlobalId, ErrorHandled};
31 use mir::GeneratorLayout;
32 use session::CrateDisambiguator;
33 use traits::{self, Reveal};
35 use ty::subst::{Subst, Substs};
36 use ty::util::{IntTypeExt, Discr};
37 use ty::walk::TypeWalker;
38 use util::captures::Captures;
39 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
40 use arena::SyncDroplessArena;
41 use session::DataTypeKind;
43 use serialize::{self, Encodable, Encoder};
44 use std::cell::RefCell;
45 use std::cmp::{self, Ordering};
47 use std::hash::{Hash, Hasher};
49 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
51 use std::vec::IntoIter;
53 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
55 use syntax::ext::hygiene::Mark;
56 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
57 use syntax_pos::{DUMMY_SP, Span};
60 use rustc_data_structures::indexed_vec::Idx;
61 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
66 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
67 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
68 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
69 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
70 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
71 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
72 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
73 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
74 pub use self::sty::RegionKind;
75 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
76 pub use self::sty::BoundRegion::*;
77 pub use self::sty::InferTy::*;
78 pub use self::sty::RegionKind::*;
79 pub use self::sty::TyKind::*;
81 pub use self::binding::BindingMode;
82 pub use self::binding::BindingMode::*;
84 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
85 pub use self::context::{Lift, TypeckTables};
87 pub use self::instance::{Instance, InstanceDef};
89 pub use self::trait_def::TraitDef;
91 pub use self::query::queries;
103 pub mod inhabitedness;
120 mod structural_impls;
125 /// The complete set of all analyses described in this module. This is
126 /// produced by the driver and fed to codegen and later passes.
128 /// NB: These contents are being migrated into queries using the
129 /// *on-demand* infrastructure.
131 pub struct CrateAnalysis {
132 pub access_levels: Lrc<AccessLevels>,
134 pub glob_map: Option<hir::GlobMap>,
138 pub struct Resolutions {
139 pub freevars: FreevarMap,
140 pub trait_map: TraitMap,
141 pub maybe_unused_trait_imports: NodeSet,
142 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
143 pub export_map: ExportMap,
144 /// Extern prelude entries. The value is `true` if the entry was introduced
145 /// via `extern crate` item and not `--extern` option or compiler built-in.
146 pub extern_prelude: FxHashMap<Name, bool>,
149 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
150 pub enum AssociatedItemContainer {
151 TraitContainer(DefId),
152 ImplContainer(DefId),
155 impl AssociatedItemContainer {
156 /// Asserts that this is the def-id of an associated item declared
157 /// in a trait, and returns the trait def-id.
158 pub fn assert_trait(&self) -> DefId {
160 TraitContainer(id) => id,
161 _ => bug!("associated item has wrong container type: {:?}", self)
165 pub fn id(&self) -> DefId {
167 TraitContainer(id) => id,
168 ImplContainer(id) => id,
173 /// The "header" of an impl is everything outside the body: a Self type, a trait
174 /// ref (in the case of a trait impl), and a set of predicates (from the
175 /// bounds/where clauses).
176 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
177 pub struct ImplHeader<'tcx> {
178 pub impl_def_id: DefId,
179 pub self_ty: Ty<'tcx>,
180 pub trait_ref: Option<TraitRef<'tcx>>,
181 pub predicates: Vec<Predicate<'tcx>>,
184 #[derive(Copy, Clone, Debug, PartialEq)]
185 pub struct AssociatedItem {
188 pub kind: AssociatedKind,
190 pub defaultness: hir::Defaultness,
191 pub container: AssociatedItemContainer,
193 /// Whether this is a method with an explicit self
194 /// as its first argument, allowing method calls.
195 pub method_has_self_argument: bool,
198 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
199 pub enum AssociatedKind {
206 impl AssociatedItem {
207 pub fn def(&self) -> Def {
209 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
210 AssociatedKind::Method => Def::Method(self.def_id),
211 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
212 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
216 /// Tests whether the associated item admits a non-trivial implementation
218 pub fn relevant_for_never<'tcx>(&self) -> bool {
220 AssociatedKind::Existential |
221 AssociatedKind::Const |
222 AssociatedKind::Type => true,
223 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
224 AssociatedKind::Method => !self.method_has_self_argument,
228 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
230 ty::AssociatedKind::Method => {
231 // We skip the binder here because the binder would deanonymize all
232 // late-bound regions, and we don't want method signatures to show up
233 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
234 // regions just fine, showing `fn(&MyType)`.
235 tcx.fn_sig(self.def_id).skip_binder().to_string()
237 ty::AssociatedKind::Type => format!("type {};", self.ident),
238 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
239 ty::AssociatedKind::Const => {
240 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
246 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
247 pub enum Visibility {
248 /// Visible everywhere (including in other crates).
250 /// Visible only in the given crate-local module.
252 /// Not visible anywhere in the local crate. This is the visibility of private external items.
256 pub trait DefIdTree: Copy {
257 fn parent(self, id: DefId) -> Option<DefId>;
259 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
260 if descendant.krate != ancestor.krate {
264 while descendant != ancestor {
265 match self.parent(descendant) {
266 Some(parent) => descendant = parent,
267 None => return false,
274 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
275 fn parent(self, id: DefId) -> Option<DefId> {
276 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
281 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt<'_, '_, '_>) -> Self {
282 match visibility.node {
283 hir::VisibilityKind::Public => Visibility::Public,
284 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
285 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
286 // If there is no resolution, `resolve` will have already reported an error, so
287 // assume that the visibility is public to avoid reporting more privacy errors.
288 Def::Err => Visibility::Public,
289 def => Visibility::Restricted(def.def_id()),
291 hir::VisibilityKind::Inherited => {
292 Visibility::Restricted(tcx.hir.get_module_parent(id))
297 /// Returns `true` if an item with this visibility is accessible from the given block.
298 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
299 let restriction = match self {
300 // Public items are visible everywhere.
301 Visibility::Public => return true,
302 // Private items from other crates are visible nowhere.
303 Visibility::Invisible => return false,
304 // Restricted items are visible in an arbitrary local module.
305 Visibility::Restricted(other) if other.krate != module.krate => return false,
306 Visibility::Restricted(module) => module,
309 tree.is_descendant_of(module, restriction)
312 /// Returns `true` if this visibility is at least as accessible as the given visibility
313 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
314 let vis_restriction = match vis {
315 Visibility::Public => return self == Visibility::Public,
316 Visibility::Invisible => return true,
317 Visibility::Restricted(module) => module,
320 self.is_accessible_from(vis_restriction, tree)
323 // Returns `true` if this item is visible anywhere in the local crate.
324 pub fn is_visible_locally(self) -> bool {
326 Visibility::Public => true,
327 Visibility::Restricted(def_id) => def_id.is_local(),
328 Visibility::Invisible => false,
333 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash)]
335 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
336 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
337 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
338 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
341 /// The crate variances map is computed during typeck and contains the
342 /// variance of every item in the local crate. You should not use it
343 /// directly, because to do so will make your pass dependent on the
344 /// HIR of every item in the local crate. Instead, use
345 /// `tcx.variances_of()` to get the variance for a *particular*
347 pub struct CrateVariancesMap {
348 /// For each item with generics, maps to a vector of the variance
349 /// of its generics. If an item has no generics, it will have no
351 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
353 /// An empty vector, useful for cloning.
354 pub empty_variance: Lrc<Vec<ty::Variance>>,
358 /// `a.xform(b)` combines the variance of a context with the
359 /// variance of a type with the following meaning. If we are in a
360 /// context with variance `a`, and we encounter a type argument in
361 /// a position with variance `b`, then `a.xform(b)` is the new
362 /// variance with which the argument appears.
368 /// Here, the "ambient" variance starts as covariant. `*mut T` is
369 /// invariant with respect to `T`, so the variance in which the
370 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
371 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
372 /// respect to its type argument `T`, and hence the variance of
373 /// the `i32` here is `Invariant.xform(Covariant)`, which results
374 /// (again) in `Invariant`.
378 /// fn(*const Vec<i32>, *mut Vec<i32)
380 /// The ambient variance is covariant. A `fn` type is
381 /// contravariant with respect to its parameters, so the variance
382 /// within which both pointer types appear is
383 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
384 /// T` is covariant with respect to `T`, so the variance within
385 /// which the first `Vec<i32>` appears is
386 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
387 /// is true for its `i32` argument. In the `*mut T` case, the
388 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
389 /// and hence the outermost type is `Invariant` with respect to
390 /// `Vec<i32>` (and its `i32` argument).
392 /// Source: Figure 1 of "Taming the Wildcards:
393 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
394 pub fn xform(self, v: ty::Variance) -> ty::Variance {
396 // Figure 1, column 1.
397 (ty::Covariant, ty::Covariant) => ty::Covariant,
398 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
399 (ty::Covariant, ty::Invariant) => ty::Invariant,
400 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
402 // Figure 1, column 2.
403 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
404 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
405 (ty::Contravariant, ty::Invariant) => ty::Invariant,
406 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
408 // Figure 1, column 3.
409 (ty::Invariant, _) => ty::Invariant,
411 // Figure 1, column 4.
412 (ty::Bivariant, _) => ty::Bivariant,
417 // Contains information needed to resolve types and (in the future) look up
418 // the types of AST nodes.
419 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
420 pub struct CReaderCacheKey {
425 // Flags that we track on types. These flags are propagated upwards
426 // through the type during type construction, so that we can quickly
427 // check whether the type has various kinds of types in it without
428 // recursing over the type itself.
430 pub struct TypeFlags: u32 {
431 const HAS_PARAMS = 1 << 0;
432 const HAS_SELF = 1 << 1;
433 const HAS_TY_INFER = 1 << 2;
434 const HAS_RE_INFER = 1 << 3;
435 const HAS_RE_SKOL = 1 << 4;
437 /// Does this have any `ReEarlyBound` regions? Used to
438 /// determine whether substitition is required, since those
439 /// represent regions that are bound in a `ty::Generics` and
440 /// hence may be substituted.
441 const HAS_RE_EARLY_BOUND = 1 << 5;
443 /// Does this have any region that "appears free" in the type?
444 /// Basically anything but `ReLateBound` and `ReErased`.
445 const HAS_FREE_REGIONS = 1 << 6;
447 /// Is an error type reachable?
448 const HAS_TY_ERR = 1 << 7;
449 const HAS_PROJECTION = 1 << 8;
451 // FIXME: Rename this to the actual property since it's used for generators too
452 const HAS_TY_CLOSURE = 1 << 9;
454 // `true` if there are "names" of types and regions and so forth
455 // that are local to a particular fn
456 const HAS_FREE_LOCAL_NAMES = 1 << 10;
458 // Present if the type belongs in a local type context.
459 // Only set for Infer other than Fresh.
460 const KEEP_IN_LOCAL_TCX = 1 << 11;
462 // Is there a projection that does not involve a bound region?
463 // Currently we can't normalize projections w/ bound regions.
464 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
466 /// Does this have any `ReLateBound` regions? Used to check
467 /// if a global bound is safe to evaluate.
468 const HAS_RE_LATE_BOUND = 1 << 13;
470 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
471 TypeFlags::HAS_SELF.bits |
472 TypeFlags::HAS_RE_EARLY_BOUND.bits;
474 // Flags representing the nominal content of a type,
475 // computed by FlagsComputation. If you add a new nominal
476 // flag, it should be added here too.
477 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
478 TypeFlags::HAS_SELF.bits |
479 TypeFlags::HAS_TY_INFER.bits |
480 TypeFlags::HAS_RE_INFER.bits |
481 TypeFlags::HAS_RE_SKOL.bits |
482 TypeFlags::HAS_RE_EARLY_BOUND.bits |
483 TypeFlags::HAS_FREE_REGIONS.bits |
484 TypeFlags::HAS_TY_ERR.bits |
485 TypeFlags::HAS_PROJECTION.bits |
486 TypeFlags::HAS_TY_CLOSURE.bits |
487 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
488 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
489 TypeFlags::HAS_RE_LATE_BOUND.bits;
493 pub struct TyS<'tcx> {
494 pub sty: TyKind<'tcx>,
495 pub flags: TypeFlags,
497 /// This is a kind of confusing thing: it stores the smallest
500 /// (a) the binder itself captures nothing but
501 /// (b) all the late-bound things within the type are captured
502 /// by some sub-binder.
504 /// So, for a type without any late-bound things, like `u32`, this
505 /// will be INNERMOST, because that is the innermost binder that
506 /// captures nothing. But for a type `&'D u32`, where `'D` is a
507 /// late-bound region with debruijn index D, this would be D+1 --
508 /// the binder itself does not capture D, but D is captured by an
511 /// We call this concept an "exclusive" binder D (because all
512 /// debruijn indices within the type are contained within `0..D`
514 outer_exclusive_binder: ty::DebruijnIndex,
517 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
518 #[cfg(target_arch = "x86_64")]
519 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
521 impl<'tcx> Ord for TyS<'tcx> {
522 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
523 self.sty.cmp(&other.sty)
527 impl<'tcx> PartialOrd for TyS<'tcx> {
528 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
529 Some(self.sty.cmp(&other.sty))
533 impl<'tcx> PartialEq for TyS<'tcx> {
535 fn eq(&self, other: &TyS<'tcx>) -> bool {
539 impl<'tcx> Eq for TyS<'tcx> {}
541 impl<'tcx> Hash for TyS<'tcx> {
542 fn hash<H: Hasher>(&self, s: &mut H) {
543 (self as *const TyS<'_>).hash(s)
547 impl<'tcx> TyS<'tcx> {
548 pub fn is_primitive_ty(&self) -> bool {
555 TyKind::Infer(InferTy::IntVar(_)) |
556 TyKind::Infer(InferTy::FloatVar(_)) |
557 TyKind::Infer(InferTy::FreshIntTy(_)) |
558 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
559 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
564 pub fn is_suggestable(&self) -> bool {
569 TyKind::Dynamic(..) |
570 TyKind::Closure(..) |
572 TyKind::Projection(..) => false,
578 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
579 fn hash_stable<W: StableHasherResult>(&self,
580 hcx: &mut StableHashingContext<'a>,
581 hasher: &mut StableHasher<W>) {
585 // The other fields just provide fast access to information that is
586 // also contained in `sty`, so no need to hash them.
589 outer_exclusive_binder: _,
592 sty.hash_stable(hcx, hasher);
596 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
598 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
599 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
601 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
604 /// A dummy type used to force List to by unsized without requiring fat pointers
605 type OpaqueListContents;
608 /// A wrapper for slices with the additional invariant
609 /// that the slice is interned and no other slice with
610 /// the same contents can exist in the same context.
611 /// This means we can use pointer for both
612 /// equality comparisons and hashing.
613 /// Note: `Slice` was already taken by the `Ty`.
618 opaque: OpaqueListContents,
621 unsafe impl<T: Sync> Sync for List<T> {}
623 impl<T: Copy> List<T> {
625 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
626 assert!(!mem::needs_drop::<T>());
627 assert!(mem::size_of::<T>() != 0);
628 assert!(slice.len() != 0);
630 // Align up the size of the len (usize) field
631 let align = mem::align_of::<T>();
632 let align_mask = align - 1;
633 let offset = mem::size_of::<usize>();
634 let offset = (offset + align_mask) & !align_mask;
636 let size = offset + slice.len() * mem::size_of::<T>();
638 let mem = arena.alloc_raw(
640 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
642 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
644 result.len = slice.len();
646 // Write the elements
647 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
648 arena_slice.copy_from_slice(slice);
655 impl<T: fmt::Debug> fmt::Debug for List<T> {
656 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
661 impl<T: Encodable> Encodable for List<T> {
663 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
668 impl<T> Ord for List<T> where T: Ord {
669 fn cmp(&self, other: &List<T>) -> Ordering {
670 if self == other { Ordering::Equal } else {
671 <[T] as Ord>::cmp(&**self, &**other)
676 impl<T> PartialOrd for List<T> where T: PartialOrd {
677 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
678 if self == other { Some(Ordering::Equal) } else {
679 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
684 impl<T: PartialEq> PartialEq for List<T> {
686 fn eq(&self, other: &List<T>) -> bool {
690 impl<T: Eq> Eq for List<T> {}
692 impl<T> Hash for List<T> {
694 fn hash<H: Hasher>(&self, s: &mut H) {
695 (self as *const List<T>).hash(s)
699 impl<T> Deref for List<T> {
702 fn deref(&self) -> &[T] {
704 slice::from_raw_parts(self.data.as_ptr(), self.len)
709 impl<'a, T> IntoIterator for &'a List<T> {
711 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
713 fn into_iter(self) -> Self::IntoIter {
718 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
722 pub fn empty<'a>() -> &'a List<T> {
723 #[repr(align(64), C)]
724 struct EmptySlice([u8; 64]);
725 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
726 assert!(mem::align_of::<T>() <= 64);
728 &*(&EMPTY_SLICE as *const _ as *const List<T>)
733 /// Upvars do not get their own node-id. Instead, we use the pair of
734 /// the original var id (that is, the root variable that is referenced
735 /// by the upvar) and the id of the closure expression.
736 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
738 pub var_id: hir::HirId,
739 pub closure_expr_id: LocalDefId,
742 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
743 pub enum BorrowKind {
744 /// Data must be immutable and is aliasable.
747 /// Data must be immutable but not aliasable. This kind of borrow
748 /// cannot currently be expressed by the user and is used only in
749 /// implicit closure bindings. It is needed when the closure
750 /// is borrowing or mutating a mutable referent, e.g.:
752 /// let x: &mut isize = ...;
753 /// let y = || *x += 5;
755 /// If we were to try to translate this closure into a more explicit
756 /// form, we'd encounter an error with the code as written:
758 /// struct Env { x: & &mut isize }
759 /// let x: &mut isize = ...;
760 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
761 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
763 /// This is then illegal because you cannot mutate a `&mut` found
764 /// in an aliasable location. To solve, you'd have to translate with
765 /// an `&mut` borrow:
767 /// struct Env { x: & &mut isize }
768 /// let x: &mut isize = ...;
769 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
770 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
772 /// Now the assignment to `**env.x` is legal, but creating a
773 /// mutable pointer to `x` is not because `x` is not mutable. We
774 /// could fix this by declaring `x` as `let mut x`. This is ok in
775 /// user code, if awkward, but extra weird for closures, since the
776 /// borrow is hidden.
778 /// So we introduce a "unique imm" borrow -- the referent is
779 /// immutable, but not aliasable. This solves the problem. For
780 /// simplicity, we don't give users the way to express this
781 /// borrow, it's just used when translating closures.
784 /// Data is mutable and not aliasable.
788 /// Information describing the capture of an upvar. This is computed
789 /// during `typeck`, specifically by `regionck`.
790 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
791 pub enum UpvarCapture<'tcx> {
792 /// Upvar is captured by value. This is always true when the
793 /// closure is labeled `move`, but can also be true in other cases
794 /// depending on inference.
797 /// Upvar is captured by reference.
798 ByRef(UpvarBorrow<'tcx>),
801 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
802 pub struct UpvarBorrow<'tcx> {
803 /// The kind of borrow: by-ref upvars have access to shared
804 /// immutable borrows, which are not part of the normal language
806 pub kind: BorrowKind,
808 /// Region of the resulting reference.
809 pub region: ty::Region<'tcx>,
812 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
814 #[derive(Copy, Clone)]
815 pub struct ClosureUpvar<'tcx> {
821 #[derive(Clone, Copy, PartialEq, Eq)]
822 pub enum IntVarValue {
824 UintType(ast::UintTy),
827 #[derive(Clone, Copy, PartialEq, Eq)]
828 pub struct FloatVarValue(pub ast::FloatTy);
830 impl ty::EarlyBoundRegion {
831 pub fn to_bound_region(&self) -> ty::BoundRegion {
832 ty::BoundRegion::BrNamed(self.def_id, self.name)
835 /// Does this early bound region have a name? Early bound regions normally
836 /// always have names except when using anonymous lifetimes (`'_`).
837 pub fn has_name(&self) -> bool {
838 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
842 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
843 pub enum GenericParamDefKind {
847 object_lifetime_default: ObjectLifetimeDefault,
848 synthetic: Option<hir::SyntheticTyParamKind>,
852 #[derive(Clone, RustcEncodable, RustcDecodable)]
853 pub struct GenericParamDef {
854 pub name: InternedString,
858 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
859 /// on generic parameter `'a`/`T`, asserts data behind the parameter
860 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
861 pub pure_wrt_drop: bool,
863 pub kind: GenericParamDefKind,
866 impl GenericParamDef {
867 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
868 if let GenericParamDefKind::Lifetime = self.kind {
869 ty::EarlyBoundRegion {
875 bug!("cannot convert a non-lifetime parameter def to an early bound region")
879 pub fn to_bound_region(&self) -> ty::BoundRegion {
880 if let GenericParamDefKind::Lifetime = self.kind {
881 self.to_early_bound_region_data().to_bound_region()
883 bug!("cannot convert a non-lifetime parameter def to an early bound region")
889 pub struct GenericParamCount {
890 pub lifetimes: usize,
894 /// Information about the formal type/lifetime parameters associated
895 /// with an item or method. Analogous to hir::Generics.
897 /// The ordering of parameters is the same as in Subst (excluding child generics):
898 /// Self (optionally), Lifetime params..., Type params...
899 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
900 pub struct Generics {
901 pub parent: Option<DefId>,
902 pub parent_count: usize,
903 pub params: Vec<GenericParamDef>,
905 /// Reverse map to the `index` field of each `GenericParamDef`
906 pub param_def_id_to_index: FxHashMap<DefId, u32>,
909 pub has_late_bound_regions: Option<Span>,
912 impl<'a, 'gcx, 'tcx> Generics {
913 pub fn count(&self) -> usize {
914 self.parent_count + self.params.len()
917 pub fn own_counts(&self) -> GenericParamCount {
918 // We could cache this as a property of `GenericParamCount`, but
919 // the aim is to refactor this away entirely eventually and the
920 // presence of this method will be a constant reminder.
921 let mut own_counts: GenericParamCount = Default::default();
923 for param in &self.params {
925 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
926 GenericParamDefKind::Type { .. } => own_counts.types += 1,
933 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
934 for param in &self.params {
936 GenericParamDefKind::Type { .. } => return true,
937 GenericParamDefKind::Lifetime => {}
940 if let Some(parent_def_id) = self.parent {
941 let parent = tcx.generics_of(parent_def_id);
942 parent.requires_monomorphization(tcx)
948 pub fn region_param(&'tcx self,
949 param: &EarlyBoundRegion,
950 tcx: TyCtxt<'a, 'gcx, 'tcx>)
951 -> &'tcx GenericParamDef
953 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
954 let param = &self.params[index as usize];
956 ty::GenericParamDefKind::Lifetime => param,
957 _ => bug!("expected lifetime parameter, but found another generic parameter")
960 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
961 .region_param(param, tcx)
965 /// Returns the `GenericParamDef` associated with this `ParamTy`.
966 pub fn type_param(&'tcx self,
968 tcx: TyCtxt<'a, 'gcx, 'tcx>)
969 -> &'tcx GenericParamDef {
970 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
971 let param = &self.params[index as usize];
973 ty::GenericParamDefKind::Type {..} => param,
974 _ => bug!("expected type parameter, but found another generic parameter")
977 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
978 .type_param(param, tcx)
983 /// Bounds on generics.
984 #[derive(Clone, Default)]
985 pub struct GenericPredicates<'tcx> {
986 pub parent: Option<DefId>,
987 pub predicates: Vec<(Predicate<'tcx>, Span)>,
990 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
991 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
993 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
994 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
995 -> InstantiatedPredicates<'tcx> {
996 let mut instantiated = InstantiatedPredicates::empty();
997 self.instantiate_into(tcx, &mut instantiated, substs);
1001 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1002 -> InstantiatedPredicates<'tcx> {
1003 InstantiatedPredicates {
1004 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1008 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1009 instantiated: &mut InstantiatedPredicates<'tcx>,
1010 substs: &Substs<'tcx>) {
1011 if let Some(def_id) = self.parent {
1012 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1014 instantiated.predicates.extend(
1015 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1019 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1020 -> InstantiatedPredicates<'tcx> {
1021 let mut instantiated = InstantiatedPredicates::empty();
1022 self.instantiate_identity_into(tcx, &mut instantiated);
1026 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1027 instantiated: &mut InstantiatedPredicates<'tcx>) {
1028 if let Some(def_id) = self.parent {
1029 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1031 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1034 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1035 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1036 -> InstantiatedPredicates<'tcx>
1038 assert_eq!(self.parent, None);
1039 InstantiatedPredicates {
1040 predicates: self.predicates.iter().map(|(pred, _)| {
1041 pred.subst_supertrait(tcx, poly_trait_ref)
1047 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1048 pub enum Predicate<'tcx> {
1049 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1050 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1051 /// would be the type parameters.
1052 Trait(PolyTraitPredicate<'tcx>),
1055 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1058 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1060 /// where `<T as TraitRef>::Name == X`, approximately.
1061 /// See the `ProjectionPredicate` struct for details.
1062 Projection(PolyProjectionPredicate<'tcx>),
1064 /// no syntax: `T` well-formed
1065 WellFormed(Ty<'tcx>),
1067 /// trait must be object-safe
1070 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1071 /// for some substitutions `...` and `T` being a closure type.
1072 /// Satisfied (or refuted) once we know the closure's kind.
1073 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1076 Subtype(PolySubtypePredicate<'tcx>),
1078 /// Constant initializer must evaluate successfully.
1079 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1082 /// The crate outlives map is computed during typeck and contains the
1083 /// outlives of every item in the local crate. You should not use it
1084 /// directly, because to do so will make your pass dependent on the
1085 /// HIR of every item in the local crate. Instead, use
1086 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1088 pub struct CratePredicatesMap<'tcx> {
1089 /// For each struct with outlive bounds, maps to a vector of the
1090 /// predicate of its outlive bounds. If an item has no outlives
1091 /// bounds, it will have no entry.
1092 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1094 /// An empty vector, useful for cloning.
1095 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1098 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1099 fn as_ref(&self) -> &Predicate<'tcx> {
1104 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1105 /// Performs a substitution suitable for going from a
1106 /// poly-trait-ref to supertraits that must hold if that
1107 /// poly-trait-ref holds. This is slightly different from a normal
1108 /// substitution in terms of what happens with bound regions. See
1109 /// lengthy comment below for details.
1110 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1111 trait_ref: &ty::PolyTraitRef<'tcx>)
1112 -> ty::Predicate<'tcx>
1114 // The interaction between HRTB and supertraits is not entirely
1115 // obvious. Let me walk you (and myself) through an example.
1117 // Let's start with an easy case. Consider two traits:
1119 // trait Foo<'a>: Bar<'a,'a> { }
1120 // trait Bar<'b,'c> { }
1122 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1123 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1124 // knew that `Foo<'x>` (for any 'x) then we also know that
1125 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1126 // normal substitution.
1128 // In terms of why this is sound, the idea is that whenever there
1129 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1130 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1131 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1134 // Another example to be careful of is this:
1136 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1137 // trait Bar1<'b,'c> { }
1139 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1140 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1141 // reason is similar to the previous example: any impl of
1142 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1143 // basically we would want to collapse the bound lifetimes from
1144 // the input (`trait_ref`) and the supertraits.
1146 // To achieve this in practice is fairly straightforward. Let's
1147 // consider the more complicated scenario:
1149 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1150 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1151 // where both `'x` and `'b` would have a DB index of 1.
1152 // The substitution from the input trait-ref is therefore going to be
1153 // `'a => 'x` (where `'x` has a DB index of 1).
1154 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1155 // early-bound parameter and `'b' is a late-bound parameter with a
1157 // - If we replace `'a` with `'x` from the input, it too will have
1158 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1159 // just as we wanted.
1161 // There is only one catch. If we just apply the substitution `'a
1162 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1163 // adjust the DB index because we substituting into a binder (it
1164 // tries to be so smart...) resulting in `for<'x> for<'b>
1165 // Bar1<'x,'b>` (we have no syntax for this, so use your
1166 // imagination). Basically the 'x will have DB index of 2 and 'b
1167 // will have DB index of 1. Not quite what we want. So we apply
1168 // the substitution to the *contents* of the trait reference,
1169 // rather than the trait reference itself (put another way, the
1170 // substitution code expects equal binding levels in the values
1171 // from the substitution and the value being substituted into, and
1172 // this trick achieves that).
1174 let substs = &trait_ref.skip_binder().substs;
1176 Predicate::Trait(ref binder) =>
1177 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1178 Predicate::Subtype(ref binder) =>
1179 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1180 Predicate::RegionOutlives(ref binder) =>
1181 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1182 Predicate::TypeOutlives(ref binder) =>
1183 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1184 Predicate::Projection(ref binder) =>
1185 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1186 Predicate::WellFormed(data) =>
1187 Predicate::WellFormed(data.subst(tcx, substs)),
1188 Predicate::ObjectSafe(trait_def_id) =>
1189 Predicate::ObjectSafe(trait_def_id),
1190 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1191 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1192 Predicate::ConstEvaluatable(def_id, const_substs) =>
1193 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1198 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1199 pub struct TraitPredicate<'tcx> {
1200 pub trait_ref: TraitRef<'tcx>
1203 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1205 impl<'tcx> TraitPredicate<'tcx> {
1206 pub fn def_id(&self) -> DefId {
1207 self.trait_ref.def_id
1210 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1211 self.trait_ref.input_types()
1214 pub fn self_ty(&self) -> Ty<'tcx> {
1215 self.trait_ref.self_ty()
1219 impl<'tcx> PolyTraitPredicate<'tcx> {
1220 pub fn def_id(&self) -> DefId {
1221 // ok to skip binder since trait def-id does not care about regions
1222 self.skip_binder().def_id()
1226 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1227 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1228 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1229 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1231 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1233 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1234 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1236 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1237 pub struct SubtypePredicate<'tcx> {
1238 pub a_is_expected: bool,
1242 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1244 /// This kind of predicate has no *direct* correspondent in the
1245 /// syntax, but it roughly corresponds to the syntactic forms:
1247 /// 1. `T: TraitRef<..., Item=Type>`
1248 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1250 /// In particular, form #1 is "desugared" to the combination of a
1251 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1252 /// predicates. Form #2 is a broader form in that it also permits
1253 /// equality between arbitrary types. Processing an instance of
1254 /// Form #2 eventually yields one of these `ProjectionPredicate`
1255 /// instances to normalize the LHS.
1256 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1257 pub struct ProjectionPredicate<'tcx> {
1258 pub projection_ty: ProjectionTy<'tcx>,
1262 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1264 impl<'tcx> PolyProjectionPredicate<'tcx> {
1265 /// Returns the `DefId` of the associated item being projected.
1266 pub fn item_def_id(&self) -> DefId {
1267 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 impl<'tcx> Predicate<'tcx> {
1346 /// Iterates over the types in this predicate. Note that in all
1347 /// cases this is skipping over a binder, so late-bound regions
1348 /// with depth 0 are bound by the predicate.
1349 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1350 let vec: Vec<_> = match *self {
1351 ty::Predicate::Trait(ref data) => {
1352 data.skip_binder().input_types().collect()
1354 ty::Predicate::Subtype(binder) => {
1355 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1358 ty::Predicate::TypeOutlives(binder) => {
1359 vec![binder.skip_binder().0]
1361 ty::Predicate::RegionOutlives(..) => {
1364 ty::Predicate::Projection(ref data) => {
1365 let inner = data.skip_binder();
1366 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1368 ty::Predicate::WellFormed(data) => {
1371 ty::Predicate::ObjectSafe(_trait_def_id) => {
1374 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1375 closure_substs.substs.types().collect()
1377 ty::Predicate::ConstEvaluatable(_, substs) => {
1378 substs.types().collect()
1382 // FIXME: The only reason to collect into a vector here is that I was
1383 // too lazy to make the full (somewhat complicated) iterator
1384 // type that would be needed here. But I wanted this fn to
1385 // return an iterator conceptually, rather than a `Vec`, so as
1386 // to be closer to `Ty::walk`.
1390 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1392 Predicate::Trait(ref t) => {
1393 Some(t.to_poly_trait_ref())
1395 Predicate::Projection(..) |
1396 Predicate::Subtype(..) |
1397 Predicate::RegionOutlives(..) |
1398 Predicate::WellFormed(..) |
1399 Predicate::ObjectSafe(..) |
1400 Predicate::ClosureKind(..) |
1401 Predicate::TypeOutlives(..) |
1402 Predicate::ConstEvaluatable(..) => {
1408 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1410 Predicate::TypeOutlives(data) => {
1413 Predicate::Trait(..) |
1414 Predicate::Projection(..) |
1415 Predicate::Subtype(..) |
1416 Predicate::RegionOutlives(..) |
1417 Predicate::WellFormed(..) |
1418 Predicate::ObjectSafe(..) |
1419 Predicate::ClosureKind(..) |
1420 Predicate::ConstEvaluatable(..) => {
1427 /// Represents the bounds declared on a particular set of type
1428 /// parameters. Should eventually be generalized into a flag list of
1429 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1430 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1431 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1432 /// the `GenericPredicates` are expressed in terms of the bound type
1433 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1434 /// represented a set of bounds for some particular instantiation,
1435 /// meaning that the generic parameters have been substituted with
1440 /// struct Foo<T,U:Bar<T>> { ... }
1442 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1443 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1444 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1445 /// [usize:Bar<isize>]]`.
1447 pub struct InstantiatedPredicates<'tcx> {
1448 pub predicates: Vec<Predicate<'tcx>>,
1451 impl<'tcx> InstantiatedPredicates<'tcx> {
1452 pub fn empty() -> InstantiatedPredicates<'tcx> {
1453 InstantiatedPredicates { predicates: vec![] }
1456 pub fn is_empty(&self) -> bool {
1457 self.predicates.is_empty()
1461 /// "Universes" are used during type- and trait-checking in the
1462 /// presence of `for<..>` binders to control what sets of names are
1463 /// visible. Universes are arranged into a tree: the root universe
1464 /// contains names that are always visible. Each child then adds a new
1465 /// set of names that are visible, in addition to those of its parent.
1466 /// We say that the child universe "extends" the parent universe with
1469 /// To make this more concrete, consider this program:
1473 /// fn bar<T>(x: T) {
1474 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1478 /// The struct name `Foo` is in the root universe U0. But the type
1479 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1480 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1481 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1482 /// region `'a` is in a universe U2 that extends U1, because we can
1483 /// name it inside the fn type but not outside.
1485 /// Universes are used to do type- and trait-checking around these
1486 /// "forall" binders (also called **universal quantification**). The
1487 /// idea is that when, in the body of `bar`, we refer to `T` as a
1488 /// type, we aren't referring to any type in particular, but rather a
1489 /// kind of "fresh" type that is distinct from all other types we have
1490 /// actually declared. This is called a **placeholder** type, and we
1491 /// use universes to talk about this. In other words, a type name in
1492 /// universe 0 always corresponds to some "ground" type that the user
1493 /// declared, but a type name in a non-zero universe is a placeholder
1494 /// type -- an idealized representative of "types in general" that we
1495 /// use for checking generic functions.
1497 pub struct UniverseIndex {
1498 DEBUG_FORMAT = "U{}",
1502 impl_stable_hash_for!(struct UniverseIndex { private });
1504 impl UniverseIndex {
1505 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1507 /// Returns the "next" universe index in order -- this new index
1508 /// is considered to extend all previous universes. This
1509 /// corresponds to entering a `forall` quantifier. So, for
1510 /// example, suppose we have this type in universe `U`:
1513 /// for<'a> fn(&'a u32)
1516 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1517 /// new universe that extends `U` -- in this new universe, we can
1518 /// name the region `'a`, but that region was not nameable from
1519 /// `U` because it was not in scope there.
1520 pub fn next_universe(self) -> UniverseIndex {
1521 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1524 /// Returns `true` if `self` can name a name from `other` -- in other words,
1525 /// if the set of names in `self` is a superset of those in
1526 /// `other` (`self >= other`).
1527 pub fn can_name(self, other: UniverseIndex) -> bool {
1528 self.private >= other.private
1531 /// Returns `true` if `self` cannot name some names from `other` -- in other
1532 /// words, if the set of names in `self` is a strict subset of
1533 /// those in `other` (`self < other`).
1534 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1535 self.private < other.private
1539 /// The "placeholder index" fully defines a placeholder region.
1540 /// Placeholder regions are identified by both a **universe** as well
1541 /// as a "bound-region" within that universe. The `bound_region` is
1542 /// basically a name -- distinct bound regions within the same
1543 /// universe are just two regions with an unknown relationship to one
1545 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1546 pub struct Placeholder {
1547 pub universe: UniverseIndex,
1548 pub name: BoundRegion,
1551 impl_stable_hash_for!(struct Placeholder { universe, name });
1553 /// When type checking, we use the `ParamEnv` to track
1554 /// details about the set of where-clauses that are in scope at this
1555 /// particular point.
1556 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1557 pub struct ParamEnv<'tcx> {
1558 /// Obligations that the caller must satisfy. This is basically
1559 /// the set of bounds on the in-scope type parameters, translated
1560 /// into Obligations, and elaborated and normalized.
1561 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1563 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1564 /// want `Reveal::All` -- note that this is always paired with an
1565 /// empty environment. To get that, use `ParamEnv::reveal()`.
1566 pub reveal: traits::Reveal,
1569 impl<'tcx> ParamEnv<'tcx> {
1570 /// Construct a trait environment suitable for contexts where
1571 /// there are no where clauses in scope. Hidden types (like `impl
1572 /// Trait`) are left hidden, so this is suitable for ordinary
1574 pub fn empty() -> Self {
1575 Self::new(List::empty(), Reveal::UserFacing)
1578 /// Construct a trait environment with no where clauses in scope
1579 /// where the values of all `impl Trait` and other hidden types
1580 /// are revealed. This is suitable for monomorphized, post-typeck
1581 /// environments like codegen or doing optimizations.
1583 /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
1584 /// or invoke `param_env.with_reveal_all()`.
1585 pub fn reveal_all() -> Self {
1586 Self::new(List::empty(), Reveal::All)
1589 /// Construct a trait environment with the given set of predicates.
1590 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1593 ty::ParamEnv { caller_bounds, reveal }
1596 /// Returns a new parameter environment with the same clauses, but
1597 /// which "reveals" the true results of projections in all cases
1598 /// (even for associated types that are specializable). This is
1599 /// the desired behavior during codegen and certain other special
1600 /// contexts; normally though we want to use `Reveal::UserFacing`,
1601 /// which is the default.
1602 pub fn with_reveal_all(self) -> Self {
1603 ty::ParamEnv { reveal: Reveal::All, ..self }
1606 /// Returns this same environment but with no caller bounds.
1607 pub fn without_caller_bounds(self) -> Self {
1608 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1611 /// Creates a suitable environment in which to perform trait
1612 /// queries on the given value. When type-checking, this is simply
1613 /// the pair of the environment plus value. But when reveal is set to
1614 /// All, then if `value` does not reference any type parameters, we will
1615 /// pair it with the empty environment. This improves caching and is generally
1618 /// NB: We preserve the environment when type-checking because it
1619 /// is possible for the user to have wacky where-clauses like
1620 /// `where Box<u32>: Copy`, which are clearly never
1621 /// satisfiable. We generally want to behave as if they were true,
1622 /// although the surrounding function is never reachable.
1623 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1625 Reveal::UserFacing => {
1634 || value.needs_infer()
1635 || value.has_param_types()
1636 || value.has_self_ty()
1644 param_env: self.without_caller_bounds(),
1653 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1654 pub struct ParamEnvAnd<'tcx, T> {
1655 pub param_env: ParamEnv<'tcx>,
1659 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1660 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1661 (self.param_env, self.value)
1665 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1666 where T: HashStable<StableHashingContext<'a>>
1668 fn hash_stable<W: StableHasherResult>(&self,
1669 hcx: &mut StableHashingContext<'a>,
1670 hasher: &mut StableHasher<W>) {
1676 param_env.hash_stable(hcx, hasher);
1677 value.hash_stable(hcx, hasher);
1681 #[derive(Copy, Clone, Debug)]
1682 pub struct Destructor {
1683 /// The def-id of the destructor method
1688 pub struct AdtFlags: u32 {
1689 const NO_ADT_FLAGS = 0;
1690 const IS_ENUM = 1 << 0;
1691 const IS_PHANTOM_DATA = 1 << 1;
1692 const IS_FUNDAMENTAL = 1 << 2;
1693 const IS_UNION = 1 << 3;
1694 const IS_BOX = 1 << 4;
1695 /// Indicates whether the type is an `Arc`.
1696 const IS_ARC = 1 << 5;
1697 /// Indicates whether the type is an `Rc`.
1698 const IS_RC = 1 << 6;
1699 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1700 /// (i.e., this flag is never set unless this ADT is an enum).
1701 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 7;
1706 pub struct VariantFlags: u32 {
1707 const NO_VARIANT_FLAGS = 0;
1708 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1709 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1714 pub struct VariantDef {
1715 /// The variant's DefId. If this is a tuple-like struct,
1716 /// this is the DefId of the struct's ctor.
1718 pub name: Name, // struct's name if this is a struct
1719 pub discr: VariantDiscr,
1720 pub fields: Vec<FieldDef>,
1721 pub ctor_kind: CtorKind,
1722 flags: VariantFlags,
1725 impl<'a, 'gcx, 'tcx> VariantDef {
1726 /// Create a new `VariantDef`.
1728 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1729 /// and for everything else, it is the variant DefId.
1730 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1731 /// this is the struct DefId for structs, and the variant DefId for variants.
1733 /// Note that we *could* use the constructor DefId, because the constructor attributes
1734 /// redirect to the base attributes, but compiling a small crate requires
1735 /// loading the AdtDefs for all the structs in the universe (e.g. coherence for any
1736 /// built-in trait), and we do not want to load attributes twice.
1738 /// If someone speeds up attribute loading to not be a performance concern, they can
1739 /// remove this hack and use the constructor DefId everywhere.
1740 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1743 discr: VariantDiscr,
1744 fields: Vec<FieldDef>,
1746 ctor_kind: CtorKind,
1747 attribute_def_id: DefId)
1750 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1751 fields, adt_kind, ctor_kind, attribute_def_id);
1752 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1753 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1754 debug!("found non-exhaustive field list for {:?}", did);
1755 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1768 pub fn is_field_list_non_exhaustive(&self) -> bool {
1769 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1773 impl_stable_hash_for!(struct VariantDef {
1782 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1783 pub enum VariantDiscr {
1784 /// Explicit value for this variant, i.e. `X = 123`.
1785 /// The `DefId` corresponds to the embedded constant.
1788 /// The previous variant's discriminant plus one.
1789 /// For efficiency reasons, the distance from the
1790 /// last `Explicit` discriminant is being stored,
1791 /// or `0` for the first variant, if it has none.
1796 pub struct FieldDef {
1799 pub vis: Visibility,
1802 /// The definition of an abstract data type - a struct or enum.
1804 /// These are all interned (by intern_adt_def) into the adt_defs
1808 pub variants: Vec<VariantDef>,
1810 pub repr: ReprOptions,
1813 impl PartialOrd for AdtDef {
1814 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1815 Some(self.cmp(&other))
1819 /// There should be only one AdtDef for each `did`, therefore
1820 /// it is fine to implement `Ord` only based on `did`.
1821 impl Ord for AdtDef {
1822 fn cmp(&self, other: &AdtDef) -> Ordering {
1823 self.did.cmp(&other.did)
1827 impl PartialEq for AdtDef {
1828 // AdtDef are always interned and this is part of TyS equality
1830 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1833 impl Eq for AdtDef {}
1835 impl Hash for AdtDef {
1837 fn hash<H: Hasher>(&self, s: &mut H) {
1838 (self as *const AdtDef).hash(s)
1842 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1843 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1848 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1851 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1852 fn hash_stable<W: StableHasherResult>(&self,
1853 hcx: &mut StableHashingContext<'a>,
1854 hasher: &mut StableHasher<W>) {
1856 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1859 let hash: Fingerprint = CACHE.with(|cache| {
1860 let addr = self as *const AdtDef as usize;
1861 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1869 let mut hasher = StableHasher::new();
1870 did.hash_stable(hcx, &mut hasher);
1871 variants.hash_stable(hcx, &mut hasher);
1872 flags.hash_stable(hcx, &mut hasher);
1873 repr.hash_stable(hcx, &mut hasher);
1879 hash.hash_stable(hcx, hasher);
1883 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1884 pub enum AdtKind { Struct, Union, Enum }
1886 impl Into<DataTypeKind> for AdtKind {
1887 fn into(self) -> DataTypeKind {
1889 AdtKind::Struct => DataTypeKind::Struct,
1890 AdtKind::Union => DataTypeKind::Union,
1891 AdtKind::Enum => DataTypeKind::Enum,
1897 #[derive(RustcEncodable, RustcDecodable, Default)]
1898 pub struct ReprFlags: u8 {
1899 const IS_C = 1 << 0;
1900 const IS_SIMD = 1 << 1;
1901 const IS_TRANSPARENT = 1 << 2;
1902 // Internal only for now. If true, don't reorder fields.
1903 const IS_LINEAR = 1 << 3;
1905 // Any of these flags being set prevent field reordering optimisation.
1906 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1907 ReprFlags::IS_SIMD.bits |
1908 ReprFlags::IS_LINEAR.bits;
1912 impl_stable_hash_for!(struct ReprFlags {
1918 /// Represents the repr options provided by the user,
1919 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1920 pub struct ReprOptions {
1921 pub int: Option<attr::IntType>,
1924 pub flags: ReprFlags,
1927 impl_stable_hash_for!(struct ReprOptions {
1935 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
1936 let mut flags = ReprFlags::empty();
1937 let mut size = None;
1938 let mut max_align = 0;
1939 let mut min_pack = 0;
1940 for attr in tcx.get_attrs(did).iter() {
1941 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
1942 flags.insert(match r {
1943 attr::ReprC => ReprFlags::IS_C,
1944 attr::ReprPacked(pack) => {
1945 min_pack = if min_pack > 0 {
1946 cmp::min(pack, min_pack)
1952 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1953 attr::ReprSimd => ReprFlags::IS_SIMD,
1954 attr::ReprInt(i) => {
1958 attr::ReprAlign(align) => {
1959 max_align = cmp::max(align, max_align);
1966 // This is here instead of layout because the choice must make it into metadata.
1967 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1968 flags.insert(ReprFlags::IS_LINEAR);
1970 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1974 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1976 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1978 pub fn packed(&self) -> bool { self.pack > 0 }
1980 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1982 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1984 pub fn discr_type(&self) -> attr::IntType {
1985 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1988 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
1989 /// layout" optimizations, such as representing `Foo<&T>` as a
1991 pub fn inhibit_enum_layout_opt(&self) -> bool {
1992 self.c() || self.int.is_some()
1995 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
1996 /// optimizations, such as with repr(C) or repr(packed(1)).
1997 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1998 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
2002 impl<'a, 'gcx, 'tcx> AdtDef {
2003 fn new(tcx: TyCtxt<'_, '_, '_>,
2006 variants: Vec<VariantDef>,
2007 repr: ReprOptions) -> Self {
2008 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2009 let mut flags = AdtFlags::NO_ADT_FLAGS;
2010 let attrs = tcx.get_attrs(did);
2011 if attr::contains_name(&attrs, "fundamental") {
2012 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2014 if Some(did) == tcx.lang_items().phantom_data() {
2015 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2017 if Some(did) == tcx.lang_items().owned_box() {
2018 flags = flags | AdtFlags::IS_BOX;
2020 if Some(did) == tcx.lang_items().arc() {
2021 flags = flags | AdtFlags::IS_ARC;
2023 if Some(did) == tcx.lang_items().rc() {
2024 flags = flags | AdtFlags::IS_RC;
2026 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2027 debug!("found non-exhaustive variant list for {:?}", did);
2028 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2031 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2032 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2033 AdtKind::Struct => {}
2044 pub fn is_struct(&self) -> bool {
2045 !self.is_union() && !self.is_enum()
2049 pub fn is_union(&self) -> bool {
2050 self.flags.intersects(AdtFlags::IS_UNION)
2054 pub fn is_enum(&self) -> bool {
2055 self.flags.intersects(AdtFlags::IS_ENUM)
2059 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2060 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2063 /// Returns the kind of the ADT - Struct or Enum.
2065 pub fn adt_kind(&self) -> AdtKind {
2068 } else if self.is_union() {
2075 pub fn descr(&self) -> &'static str {
2076 match self.adt_kind() {
2077 AdtKind::Struct => "struct",
2078 AdtKind::Union => "union",
2079 AdtKind::Enum => "enum",
2083 pub fn variant_descr(&self) -> &'static str {
2084 match self.adt_kind() {
2085 AdtKind::Struct => "struct",
2086 AdtKind::Union => "union",
2087 AdtKind::Enum => "variant",
2091 /// Returns whether this type is #[fundamental] for the purposes
2092 /// of coherence checking.
2094 pub fn is_fundamental(&self) -> bool {
2095 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2098 /// Returns `true` if this is PhantomData<T>.
2100 pub fn is_phantom_data(&self) -> bool {
2101 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
2104 /// Returns `true` if this is `Arc<T>`.
2105 pub fn is_arc(&self) -> bool {
2106 self.flags.intersects(AdtFlags::IS_ARC)
2109 /// Returns `true` if this is `Rc<T>`.
2110 pub fn is_rc(&self) -> bool {
2111 self.flags.intersects(AdtFlags::IS_RC)
2114 /// Returns `true` if this is Box<T>.
2116 pub fn is_box(&self) -> bool {
2117 self.flags.intersects(AdtFlags::IS_BOX)
2120 /// Returns whether this type has a destructor.
2121 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2122 self.destructor(tcx).is_some()
2125 /// Asserts this is a struct or union and returns its unique variant.
2126 pub fn non_enum_variant(&self) -> &VariantDef {
2127 assert!(self.is_struct() || self.is_union());
2132 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
2133 tcx.predicates_of(self.did)
2136 /// Returns an iterator over all fields contained
2139 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2140 self.variants.iter().flat_map(|v| v.fields.iter())
2143 pub fn is_payloadfree(&self) -> bool {
2144 !self.variants.is_empty() &&
2145 self.variants.iter().all(|v| v.fields.is_empty())
2148 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2151 .find(|v| v.did == vid)
2152 .expect("variant_with_id: unknown variant")
2155 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
2158 .position(|v| v.did == vid)
2159 .expect("variant_index_with_id: unknown variant")
2162 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2164 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2165 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2166 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2167 Def::SelfCtor(..) => self.non_enum_variant(),
2168 _ => bug!("unexpected def {:?} in variant_of_def", def)
2173 pub fn eval_explicit_discr(
2175 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2177 ) -> Option<Discr<'tcx>> {
2178 let param_env = ParamEnv::empty();
2179 let repr_type = self.repr.discr_type();
2180 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2181 let instance = ty::Instance::new(expr_did, substs);
2182 let cid = GlobalId {
2186 match tcx.const_eval(param_env.and(cid)) {
2188 // FIXME: Find the right type and use it instead of `val.ty` here
2189 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2190 trace!("discriminants: {} ({:?})", b, repr_type);
2196 info!("invalid enum discriminant: {:#?}", val);
2197 ::mir::interpret::struct_error(
2198 tcx.at(tcx.def_span(expr_did)),
2199 "constant evaluation of enum discriminant resulted in non-integer",
2204 Err(ErrorHandled::Reported) => {
2205 if !expr_did.is_local() {
2206 span_bug!(tcx.def_span(expr_did),
2207 "variant discriminant evaluation succeeded \
2208 in its crate but failed locally");
2212 Err(ErrorHandled::TooGeneric) => span_bug!(
2213 tcx.def_span(expr_did),
2214 "enum discriminant depends on generic arguments",
2220 pub fn discriminants(
2222 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2223 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
2224 let repr_type = self.repr.discr_type();
2225 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2226 let mut prev_discr = None::<Discr<'tcx>>;
2227 self.variants.iter().map(move |v| {
2228 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2229 if let VariantDiscr::Explicit(expr_did) = v.discr {
2230 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2234 prev_discr = Some(discr);
2240 /// Compute the discriminant value used by a specific variant.
2241 /// Unlike `discriminants`, this is (amortized) constant-time,
2242 /// only doing at most one query for evaluating an explicit
2243 /// discriminant (the last one before the requested variant),
2244 /// assuming there are no constant-evaluation errors there.
2245 pub fn discriminant_for_variant(&self,
2246 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2247 variant_index: usize)
2249 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2250 let explicit_value = val
2251 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2252 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2253 explicit_value.checked_add(tcx, offset as u128).0
2256 /// Yields a DefId for the discriminant and an offset to add to it
2257 /// Alternatively, if there is no explicit discriminant, returns the
2258 /// inferred discriminant directly
2259 pub fn discriminant_def_for_variant(
2261 variant_index: usize,
2262 ) -> (Option<DefId>, usize) {
2263 let mut explicit_index = variant_index;
2266 match self.variants[explicit_index].discr {
2267 ty::VariantDiscr::Relative(0) => {
2271 ty::VariantDiscr::Relative(distance) => {
2272 explicit_index -= distance;
2274 ty::VariantDiscr::Explicit(did) => {
2275 expr_did = Some(did);
2280 (expr_did, variant_index - explicit_index)
2283 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2284 tcx.adt_destructor(self.did)
2287 /// Returns a list of types such that `Self: Sized` if and only
2288 /// if that type is Sized, or `TyErr` if this type is recursive.
2290 /// Oddly enough, checking that the sized-constraint is Sized is
2291 /// actually more expressive than checking all members:
2292 /// the Sized trait is inductive, so an associated type that references
2293 /// Self would prevent its containing ADT from being Sized.
2295 /// Due to normalization being eager, this applies even if
2296 /// the associated type is behind a pointer, e.g. issue #31299.
2297 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2298 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2301 debug!("adt_sized_constraint: {:?} is recursive", self);
2302 // This should be reported as an error by `check_representable`.
2304 // Consider the type as Sized in the meanwhile to avoid
2305 // further errors. Delay our `bug` diagnostic here to get
2306 // emitted later as well in case we accidentally otherwise don't
2309 tcx.intern_type_list(&[tcx.types.err])
2314 fn sized_constraint_for_ty(&self,
2315 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2318 let result = match ty.sty {
2319 Bool | Char | Int(..) | Uint(..) | Float(..) |
2320 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2321 Array(..) | Closure(..) | Generator(..) | Never => {
2330 GeneratorWitness(..) => {
2331 // these are never sized - return the target type
2338 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2342 Adt(adt, substs) => {
2344 let adt_tys = adt.sized_constraint(tcx);
2345 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2348 .map(|ty| ty.subst(tcx, substs))
2349 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2353 Projection(..) | Opaque(..) => {
2354 // must calculate explicitly.
2355 // FIXME: consider special-casing always-Sized projections
2359 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2362 // perf hack: if there is a `T: Sized` bound, then
2363 // we know that `T` is Sized and do not need to check
2366 let sized_trait = match tcx.lang_items().sized_trait() {
2368 _ => return vec![ty]
2370 let sized_predicate = Binder::dummy(TraitRef {
2371 def_id: sized_trait,
2372 substs: tcx.mk_substs_trait(ty, &[])
2374 let predicates = tcx.predicates_of(self.did).predicates;
2375 if predicates.into_iter().any(|(p, _)| p == sized_predicate) {
2384 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2388 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2393 impl<'a, 'gcx, 'tcx> FieldDef {
2394 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2395 tcx.type_of(self.did).subst(tcx, subst)
2399 /// Represents the various closure traits in the Rust language. This
2400 /// will determine the type of the environment (`self`, in the
2401 /// desuaring) argument that the closure expects.
2403 /// You can get the environment type of a closure using
2404 /// `tcx.closure_env_ty()`.
2405 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2406 pub enum ClosureKind {
2407 // Warning: Ordering is significant here! The ordering is chosen
2408 // because the trait Fn is a subtrait of FnMut and so in turn, and
2409 // hence we order it so that Fn < FnMut < FnOnce.
2415 impl<'a, 'tcx> ClosureKind {
2416 // This is the initial value used when doing upvar inference.
2417 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2419 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2421 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2422 ClosureKind::FnMut => {
2423 tcx.require_lang_item(FnMutTraitLangItem)
2425 ClosureKind::FnOnce => {
2426 tcx.require_lang_item(FnOnceTraitLangItem)
2431 /// Returns `true` if this a type that impls this closure kind
2432 /// must also implement `other`.
2433 pub fn extends(self, other: ty::ClosureKind) -> bool {
2434 match (self, other) {
2435 (ClosureKind::Fn, ClosureKind::Fn) => true,
2436 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2437 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2438 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2439 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2440 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2445 /// Returns the representative scalar type for this closure kind.
2446 /// See `TyS::to_opt_closure_kind` for more details.
2447 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2449 ty::ClosureKind::Fn => tcx.types.i8,
2450 ty::ClosureKind::FnMut => tcx.types.i16,
2451 ty::ClosureKind::FnOnce => tcx.types.i32,
2456 impl<'tcx> TyS<'tcx> {
2457 /// Iterator that walks `self` and any types reachable from
2458 /// `self`, in depth-first order. Note that just walks the types
2459 /// that appear in `self`, it does not descend into the fields of
2460 /// structs or variants. For example:
2463 /// isize => { isize }
2464 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2465 /// [isize] => { [isize], isize }
2467 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2468 TypeWalker::new(self)
2471 /// Iterator that walks the immediate children of `self`. Hence
2472 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2473 /// (but not `i32`, like `walk`).
2474 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2475 walk::walk_shallow(self)
2478 /// Walks `ty` and any types appearing within `ty`, invoking the
2479 /// callback `f` on each type. If the callback returns false, then the
2480 /// children of the current type are ignored.
2482 /// Note: prefer `ty.walk()` where possible.
2483 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2484 where F: FnMut(Ty<'tcx>) -> bool
2486 let mut walker = self.walk();
2487 while let Some(ty) = walker.next() {
2489 walker.skip_current_subtree();
2496 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2498 hir::MutMutable => MutBorrow,
2499 hir::MutImmutable => ImmBorrow,
2503 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2504 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2505 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2507 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2509 MutBorrow => hir::MutMutable,
2510 ImmBorrow => hir::MutImmutable,
2512 // We have no type corresponding to a unique imm borrow, so
2513 // use `&mut`. It gives all the capabilities of an `&uniq`
2514 // and hence is a safe "over approximation".
2515 UniqueImmBorrow => hir::MutMutable,
2519 pub fn to_user_str(&self) -> &'static str {
2521 MutBorrow => "mutable",
2522 ImmBorrow => "immutable",
2523 UniqueImmBorrow => "uniquely immutable",
2528 #[derive(Debug, Clone)]
2529 pub enum Attributes<'gcx> {
2530 Owned(Lrc<[ast::Attribute]>),
2531 Borrowed(&'gcx [ast::Attribute])
2534 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2535 type Target = [ast::Attribute];
2537 fn deref(&self) -> &[ast::Attribute] {
2539 &Attributes::Owned(ref data) => &data,
2540 &Attributes::Borrowed(data) => data
2545 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2546 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2547 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2550 /// Returns an iterator of the def-ids for all body-owners in this
2551 /// crate. If you would prefer to iterate over the bodies
2552 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2555 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2559 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2562 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2563 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2564 f(self.hir.body_owner_def_id(body_id))
2568 pub fn expr_span(self, id: NodeId) -> Span {
2569 match self.hir.find(id) {
2570 Some(Node::Expr(e)) => {
2574 bug!("Node id {} is not an expr: {:?}", id, f);
2577 bug!("Node id {} is not present in the node map", id);
2582 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2583 self.associated_items(id)
2584 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2588 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2589 self.associated_items(did).any(|item| {
2590 item.relevant_for_never()
2594 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2595 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2596 match self.hir.get(node_id) {
2597 Node::TraitItem(_) | Node::ImplItem(_) => true,
2601 match self.describe_def(def_id).expect("no def for def-id") {
2602 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2607 if is_associated_item {
2608 Some(self.associated_item(def_id))
2614 fn associated_item_from_trait_item_ref(self,
2615 parent_def_id: DefId,
2616 parent_vis: &hir::Visibility,
2617 trait_item_ref: &hir::TraitItemRef)
2619 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2620 let (kind, has_self) = match trait_item_ref.kind {
2621 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2622 hir::AssociatedItemKind::Method { has_self } => {
2623 (ty::AssociatedKind::Method, has_self)
2625 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2626 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2630 ident: trait_item_ref.ident,
2632 // Visibility of trait items is inherited from their traits.
2633 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2634 defaultness: trait_item_ref.defaultness,
2636 container: TraitContainer(parent_def_id),
2637 method_has_self_argument: has_self
2641 fn associated_item_from_impl_item_ref(self,
2642 parent_def_id: DefId,
2643 impl_item_ref: &hir::ImplItemRef)
2645 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2646 let (kind, has_self) = match impl_item_ref.kind {
2647 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2648 hir::AssociatedItemKind::Method { has_self } => {
2649 (ty::AssociatedKind::Method, has_self)
2651 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2652 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2656 ident: impl_item_ref.ident,
2658 // Visibility of trait impl items doesn't matter.
2659 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2660 defaultness: impl_item_ref.defaultness,
2662 container: ImplContainer(parent_def_id),
2663 method_has_self_argument: has_self
2667 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2668 let hir_id = self.hir.node_to_hir_id(node_id);
2669 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2672 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2673 variant.fields.iter().position(|field| {
2674 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2678 pub fn associated_items(
2681 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2682 // Ideally, we would use `-> impl Iterator` here, but it falls
2683 // afoul of the conservative "capture [restrictions]" we put
2684 // in place, so we use a hand-written iterator.
2686 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2687 AssociatedItemsIterator {
2689 def_ids: self.associated_item_def_ids(def_id),
2694 /// Returns `true` if the impls are the same polarity and the trait either
2695 /// has no items or is annotated #[marker] and prevents item overrides.
2696 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2697 if self.features().overlapping_marker_traits {
2698 let trait1_is_empty = self.impl_trait_ref(def_id1)
2699 .map_or(false, |trait_ref| {
2700 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2702 let trait2_is_empty = self.impl_trait_ref(def_id2)
2703 .map_or(false, |trait_ref| {
2704 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2706 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2709 } else if self.features().marker_trait_attr {
2710 let is_marker_impl = |def_id: DefId| -> bool {
2711 let trait_ref = self.impl_trait_ref(def_id);
2712 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2714 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2715 && is_marker_impl(def_id1)
2716 && is_marker_impl(def_id2)
2722 // Returns `ty::VariantDef` if `def` refers to a struct,
2723 // or variant or their constructors, panics otherwise.
2724 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2726 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2727 let enum_did = self.parent_def_id(did).unwrap();
2728 self.adt_def(enum_did).variant_with_id(did)
2730 Def::Struct(did) | Def::Union(did) => {
2731 self.adt_def(did).non_enum_variant()
2733 Def::StructCtor(ctor_did, ..) => {
2734 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2735 self.adt_def(did).non_enum_variant()
2737 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2741 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2742 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2743 let def_key = self.def_key(variant_def.did);
2744 match def_key.disambiguated_data.data {
2745 // for enum variants and tuple structs, the def-id of the ADT itself
2746 // is the *parent* of the variant
2747 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2748 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2750 // otherwise, for structs and unions, they share a def-id
2751 _ => variant_def.did,
2755 pub fn item_name(self, id: DefId) -> InternedString {
2756 if id.index == CRATE_DEF_INDEX {
2757 self.original_crate_name(id.krate).as_interned_str()
2759 let def_key = self.def_key(id);
2760 // The name of a StructCtor is that of its struct parent.
2761 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2762 self.item_name(DefId {
2764 index: def_key.parent.unwrap()
2767 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2768 bug!("item_name: no name for {:?}", self.def_path(id));
2774 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2775 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2779 ty::InstanceDef::Item(did) => {
2780 self.optimized_mir(did)
2782 ty::InstanceDef::VtableShim(..) |
2783 ty::InstanceDef::Intrinsic(..) |
2784 ty::InstanceDef::FnPtrShim(..) |
2785 ty::InstanceDef::Virtual(..) |
2786 ty::InstanceDef::ClosureOnceShim { .. } |
2787 ty::InstanceDef::DropGlue(..) |
2788 ty::InstanceDef::CloneShim(..) => {
2789 self.mir_shims(instance)
2794 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2795 /// Returns None if there is no MIR for the DefId
2796 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2797 if self.is_mir_available(did) {
2798 Some(self.optimized_mir(did))
2804 /// Get the attributes of a definition.
2805 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2806 if let Some(id) = self.hir.as_local_node_id(did) {
2807 Attributes::Borrowed(self.hir.attrs(id))
2809 Attributes::Owned(self.item_attrs(did))
2813 /// Determine whether an item is annotated with an attribute.
2814 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2815 attr::contains_name(&self.get_attrs(did), attr)
2818 /// Returns `true` if this is an `auto trait`.
2819 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2820 self.trait_def(trait_def_id).has_auto_impl
2823 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2824 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2827 /// Given the def-id of an impl, return the def_id of the trait it implements.
2828 /// If it implements no trait, return `None`.
2829 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2830 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2833 /// If the given defid describes a method belonging to an impl, return the
2834 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2835 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2836 let item = if def_id.krate != LOCAL_CRATE {
2837 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2838 Some(self.associated_item(def_id))
2843 self.opt_associated_item(def_id)
2846 item.and_then(|trait_item|
2847 match trait_item.container {
2848 TraitContainer(_) => None,
2849 ImplContainer(def_id) => Some(def_id),
2854 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2855 /// with the name of the crate containing the impl.
2856 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2857 if impl_did.is_local() {
2858 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2859 Ok(self.hir.span(node_id))
2861 Err(self.crate_name(impl_did.krate))
2865 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2866 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2867 // definition's parent/scope to perform comparison.
2868 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2869 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2872 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2873 ident = ident.modern();
2874 let target_expansion = match scope.krate {
2875 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2878 let scope = match ident.span.adjust(target_expansion) {
2879 Some(actual_expansion) =>
2880 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2881 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2882 None => self.hir.get_module_parent(block),
2888 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
2889 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2890 def_ids: Lrc<Vec<DefId>>,
2894 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
2895 type Item = AssociatedItem;
2897 fn next(&mut self) -> Option<AssociatedItem> {
2898 let def_id = self.def_ids.get(self.next_index)?;
2899 self.next_index += 1;
2900 Some(self.tcx.associated_item(*def_id))
2904 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2905 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2906 F: FnOnce(&[hir::Freevar]) -> T,
2908 let def_id = self.hir.local_def_id(fid);
2909 match self.freevars(def_id) {
2916 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
2917 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2918 let parent_id = tcx.hir.get_parent(id);
2919 let parent_def_id = tcx.hir.local_def_id(parent_id);
2920 let parent_item = tcx.hir.expect_item(parent_id);
2921 match parent_item.node {
2922 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2923 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2924 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2926 debug_assert_eq!(assoc_item.def_id, def_id);
2931 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2932 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2933 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2936 debug_assert_eq!(assoc_item.def_id, def_id);
2944 span_bug!(parent_item.span,
2945 "unexpected parent of trait or impl item or item not found: {:?}",
2949 /// Calculates the Sized-constraint.
2951 /// In fact, there are only a few options for the types in the constraint:
2952 /// - an obviously-unsized type
2953 /// - a type parameter or projection whose Sizedness can't be known
2954 /// - a tuple of type parameters or projections, if there are multiple
2956 /// - a Error, if a type contained itself. The representability
2957 /// check should catch this case.
2958 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2960 -> &'tcx [Ty<'tcx>] {
2961 let def = tcx.adt_def(def_id);
2963 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
2966 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2969 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2974 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2976 -> Lrc<Vec<DefId>> {
2977 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2978 let item = tcx.hir.expect_item(id);
2979 let vec: Vec<_> = match item.node {
2980 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2981 trait_item_refs.iter()
2982 .map(|trait_item_ref| trait_item_ref.id)
2983 .map(|id| tcx.hir.local_def_id(id.node_id))
2986 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2987 impl_item_refs.iter()
2988 .map(|impl_item_ref| impl_item_ref.id)
2989 .map(|id| tcx.hir.local_def_id(id.node_id))
2992 hir::ItemKind::TraitAlias(..) => vec![],
2993 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2998 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2999 tcx.hir.span_if_local(def_id).unwrap()
3002 /// If the given def ID describes an item belonging to a trait,
3003 /// return the ID of the trait that the trait item belongs to.
3004 /// Otherwise, return `None`.
3005 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3006 tcx.opt_associated_item(def_id)
3007 .and_then(|associated_item| {
3008 match associated_item.container {
3009 TraitContainer(def_id) => Some(def_id),
3010 ImplContainer(_) => None
3015 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3016 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3017 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3018 if let Node::Item(item) = tcx.hir.get(node_id) {
3019 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3020 return exist_ty.impl_trait_fn;
3027 /// Returns `true` if `def_id` is a trait alias.
3028 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3029 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3030 if let Node::Item(item) = tcx.hir.get(node_id) {
3031 if let hir::ItemKind::TraitAlias(..) = item.node {
3039 /// See `ParamEnv` struct definition for details.
3040 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3044 // The param_env of an impl Trait type is its defining function's param_env
3045 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3046 return param_env(tcx, parent);
3048 // Compute the bounds on Self and the type parameters.
3050 let InstantiatedPredicates { predicates } =
3051 tcx.predicates_of(def_id).instantiate_identity(tcx);
3053 // Finally, we have to normalize the bounds in the environment, in
3054 // case they contain any associated type projections. This process
3055 // can yield errors if the put in illegal associated types, like
3056 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3057 // report these errors right here; this doesn't actually feel
3058 // right to me, because constructing the environment feels like a
3059 // kind of a "idempotent" action, but I'm not sure where would be
3060 // a better place. In practice, we construct environments for
3061 // every fn once during type checking, and we'll abort if there
3062 // are any errors at that point, so after type checking you can be
3063 // sure that this will succeed without errors anyway.
3065 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3066 traits::Reveal::UserFacing);
3068 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3069 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3071 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3072 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3075 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3076 crate_num: CrateNum) -> CrateDisambiguator {
3077 assert_eq!(crate_num, LOCAL_CRATE);
3078 tcx.sess.local_crate_disambiguator()
3081 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3082 crate_num: CrateNum) -> Symbol {
3083 assert_eq!(crate_num, LOCAL_CRATE);
3084 tcx.crate_name.clone()
3087 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3088 crate_num: CrateNum)
3090 assert_eq!(crate_num, LOCAL_CRATE);
3094 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3095 instance_def: InstanceDef<'tcx>)
3097 match instance_def {
3098 InstanceDef::Item(..) |
3099 InstanceDef::DropGlue(..) => {
3100 let mir = tcx.instance_mir(instance_def);
3101 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3103 // Estimate the size of other compiler-generated shims to be 1.
3108 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3109 context::provide(providers);
3110 erase_regions::provide(providers);
3111 layout::provide(providers);
3112 util::provide(providers);
3113 constness::provide(providers);
3114 *providers = ty::query::Providers {
3116 associated_item_def_ids,
3117 adt_sized_constraint,
3121 crate_disambiguator,
3122 original_crate_name,
3124 trait_impls_of: trait_def::trait_impls_of_provider,
3125 instance_def_size_estimate,
3130 /// A map for the local crate mapping each type to a vector of its
3131 /// inherent impls. This is not meant to be used outside of coherence;
3132 /// rather, you should request the vector for a specific type via
3133 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3134 /// (constructing this map requires touching the entire crate).
3135 #[derive(Clone, Debug)]
3136 pub struct CrateInherentImpls {
3137 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3140 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3141 pub struct SymbolName {
3142 // FIXME: we don't rely on interning or equality here - better have
3143 // this be a `&'tcx str`.
3144 pub name: InternedString
3147 impl_stable_hash_for!(struct self::SymbolName {
3152 pub fn new(name: &str) -> SymbolName {
3154 name: Symbol::intern(name).as_interned_str()
3158 pub fn as_str(&self) -> LocalInternedString {
3163 impl fmt::Display for SymbolName {
3164 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3165 fmt::Display::fmt(&self.name, fmt)
3169 impl fmt::Debug for SymbolName {
3170 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3171 fmt::Display::fmt(&self.name, fmt)