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 impl<'tcx> Ord for TyS<'tcx> {
518 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
519 self.sty.cmp(&other.sty)
523 impl<'tcx> PartialOrd for TyS<'tcx> {
524 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
525 Some(self.sty.cmp(&other.sty))
529 impl<'tcx> PartialEq for TyS<'tcx> {
531 fn eq(&self, other: &TyS<'tcx>) -> bool {
535 impl<'tcx> Eq for TyS<'tcx> {}
537 impl<'tcx> Hash for TyS<'tcx> {
538 fn hash<H: Hasher>(&self, s: &mut H) {
539 (self as *const TyS<'_>).hash(s)
543 impl<'tcx> TyS<'tcx> {
544 pub fn is_primitive_ty(&self) -> bool {
551 TyKind::Infer(InferTy::IntVar(_)) |
552 TyKind::Infer(InferTy::FloatVar(_)) |
553 TyKind::Infer(InferTy::FreshIntTy(_)) |
554 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
555 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
560 pub fn is_suggestable(&self) -> bool {
565 TyKind::Dynamic(..) |
566 TyKind::Closure(..) |
568 TyKind::Projection(..) => false,
574 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
575 fn hash_stable<W: StableHasherResult>(&self,
576 hcx: &mut StableHashingContext<'a>,
577 hasher: &mut StableHasher<W>) {
581 // The other fields just provide fast access to information that is
582 // also contained in `sty`, so no need to hash them.
585 outer_exclusive_binder: _,
588 sty.hash_stable(hcx, hasher);
592 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
594 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
595 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
597 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
600 /// A dummy type used to force List to by unsized without requiring fat pointers
601 type OpaqueListContents;
604 /// A wrapper for slices with the additional invariant
605 /// that the slice is interned and no other slice with
606 /// the same contents can exist in the same context.
607 /// This means we can use pointer for both
608 /// equality comparisons and hashing.
609 /// Note: `Slice` was already taken by the `Ty`.
614 opaque: OpaqueListContents,
617 unsafe impl<T: Sync> Sync for List<T> {}
619 impl<T: Copy> List<T> {
621 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
622 assert!(!mem::needs_drop::<T>());
623 assert!(mem::size_of::<T>() != 0);
624 assert!(slice.len() != 0);
626 // Align up the size of the len (usize) field
627 let align = mem::align_of::<T>();
628 let align_mask = align - 1;
629 let offset = mem::size_of::<usize>();
630 let offset = (offset + align_mask) & !align_mask;
632 let size = offset + slice.len() * mem::size_of::<T>();
634 let mem = arena.alloc_raw(
636 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
638 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
640 result.len = slice.len();
642 // Write the elements
643 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
644 arena_slice.copy_from_slice(slice);
651 impl<T: fmt::Debug> fmt::Debug for List<T> {
652 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
657 impl<T: Encodable> Encodable for List<T> {
659 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
664 impl<T> Ord for List<T> where T: Ord {
665 fn cmp(&self, other: &List<T>) -> Ordering {
666 if self == other { Ordering::Equal } else {
667 <[T] as Ord>::cmp(&**self, &**other)
672 impl<T> PartialOrd for List<T> where T: PartialOrd {
673 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
674 if self == other { Some(Ordering::Equal) } else {
675 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
680 impl<T: PartialEq> PartialEq for List<T> {
682 fn eq(&self, other: &List<T>) -> bool {
686 impl<T: Eq> Eq for List<T> {}
688 impl<T> Hash for List<T> {
690 fn hash<H: Hasher>(&self, s: &mut H) {
691 (self as *const List<T>).hash(s)
695 impl<T> Deref for List<T> {
698 fn deref(&self) -> &[T] {
700 slice::from_raw_parts(self.data.as_ptr(), self.len)
705 impl<'a, T> IntoIterator for &'a List<T> {
707 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
709 fn into_iter(self) -> Self::IntoIter {
714 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
718 pub fn empty<'a>() -> &'a List<T> {
719 #[repr(align(64), C)]
720 struct EmptySlice([u8; 64]);
721 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
722 assert!(mem::align_of::<T>() <= 64);
724 &*(&EMPTY_SLICE as *const _ as *const List<T>)
729 /// Upvars do not get their own node-id. Instead, we use the pair of
730 /// the original var id (that is, the root variable that is referenced
731 /// by the upvar) and the id of the closure expression.
732 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
734 pub var_id: hir::HirId,
735 pub closure_expr_id: LocalDefId,
738 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
739 pub enum BorrowKind {
740 /// Data must be immutable and is aliasable.
743 /// Data must be immutable but not aliasable. This kind of borrow
744 /// cannot currently be expressed by the user and is used only in
745 /// implicit closure bindings. It is needed when the closure
746 /// is borrowing or mutating a mutable referent, e.g.:
748 /// let x: &mut isize = ...;
749 /// let y = || *x += 5;
751 /// If we were to try to translate this closure into a more explicit
752 /// form, we'd encounter an error with the code as written:
754 /// struct Env { x: & &mut isize }
755 /// let x: &mut isize = ...;
756 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
757 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
759 /// This is then illegal because you cannot mutate a `&mut` found
760 /// in an aliasable location. To solve, you'd have to translate with
761 /// an `&mut` borrow:
763 /// struct Env { x: & &mut isize }
764 /// let x: &mut isize = ...;
765 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
766 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
768 /// Now the assignment to `**env.x` is legal, but creating a
769 /// mutable pointer to `x` is not because `x` is not mutable. We
770 /// could fix this by declaring `x` as `let mut x`. This is ok in
771 /// user code, if awkward, but extra weird for closures, since the
772 /// borrow is hidden.
774 /// So we introduce a "unique imm" borrow -- the referent is
775 /// immutable, but not aliasable. This solves the problem. For
776 /// simplicity, we don't give users the way to express this
777 /// borrow, it's just used when translating closures.
780 /// Data is mutable and not aliasable.
784 /// Information describing the capture of an upvar. This is computed
785 /// during `typeck`, specifically by `regionck`.
786 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
787 pub enum UpvarCapture<'tcx> {
788 /// Upvar is captured by value. This is always true when the
789 /// closure is labeled `move`, but can also be true in other cases
790 /// depending on inference.
793 /// Upvar is captured by reference.
794 ByRef(UpvarBorrow<'tcx>),
797 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
798 pub struct UpvarBorrow<'tcx> {
799 /// The kind of borrow: by-ref upvars have access to shared
800 /// immutable borrows, which are not part of the normal language
802 pub kind: BorrowKind,
804 /// Region of the resulting reference.
805 pub region: ty::Region<'tcx>,
808 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
810 #[derive(Copy, Clone)]
811 pub struct ClosureUpvar<'tcx> {
817 #[derive(Clone, Copy, PartialEq, Eq)]
818 pub enum IntVarValue {
820 UintType(ast::UintTy),
823 #[derive(Clone, Copy, PartialEq, Eq)]
824 pub struct FloatVarValue(pub ast::FloatTy);
826 impl ty::EarlyBoundRegion {
827 pub fn to_bound_region(&self) -> ty::BoundRegion {
828 ty::BoundRegion::BrNamed(self.def_id, self.name)
831 /// Does this early bound region have a name? Early bound regions normally
832 /// always have names except when using anonymous lifetimes (`'_`).
833 pub fn has_name(&self) -> bool {
834 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
838 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
839 pub enum GenericParamDefKind {
843 object_lifetime_default: ObjectLifetimeDefault,
844 synthetic: Option<hir::SyntheticTyParamKind>,
848 #[derive(Clone, RustcEncodable, RustcDecodable)]
849 pub struct GenericParamDef {
850 pub name: InternedString,
854 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
855 /// on generic parameter `'a`/`T`, asserts data behind the parameter
856 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
857 pub pure_wrt_drop: bool,
859 pub kind: GenericParamDefKind,
862 impl GenericParamDef {
863 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
864 if let GenericParamDefKind::Lifetime = self.kind {
865 ty::EarlyBoundRegion {
871 bug!("cannot convert a non-lifetime parameter def to an early bound region")
875 pub fn to_bound_region(&self) -> ty::BoundRegion {
876 if let GenericParamDefKind::Lifetime = self.kind {
877 self.to_early_bound_region_data().to_bound_region()
879 bug!("cannot convert a non-lifetime parameter def to an early bound region")
885 pub struct GenericParamCount {
886 pub lifetimes: usize,
890 /// Information about the formal type/lifetime parameters associated
891 /// with an item or method. Analogous to hir::Generics.
893 /// The ordering of parameters is the same as in Subst (excluding child generics):
894 /// Self (optionally), Lifetime params..., Type params...
895 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
896 pub struct Generics {
897 pub parent: Option<DefId>,
898 pub parent_count: usize,
899 pub params: Vec<GenericParamDef>,
901 /// Reverse map to the `index` field of each `GenericParamDef`
902 pub param_def_id_to_index: FxHashMap<DefId, u32>,
905 pub has_late_bound_regions: Option<Span>,
908 impl<'a, 'gcx, 'tcx> Generics {
909 pub fn count(&self) -> usize {
910 self.parent_count + self.params.len()
913 pub fn own_counts(&self) -> GenericParamCount {
914 // We could cache this as a property of `GenericParamCount`, but
915 // the aim is to refactor this away entirely eventually and the
916 // presence of this method will be a constant reminder.
917 let mut own_counts: GenericParamCount = Default::default();
919 for param in &self.params {
921 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
922 GenericParamDefKind::Type { .. } => own_counts.types += 1,
929 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
930 for param in &self.params {
932 GenericParamDefKind::Type { .. } => return true,
933 GenericParamDefKind::Lifetime => {}
936 if let Some(parent_def_id) = self.parent {
937 let parent = tcx.generics_of(parent_def_id);
938 parent.requires_monomorphization(tcx)
944 pub fn region_param(&'tcx self,
945 param: &EarlyBoundRegion,
946 tcx: TyCtxt<'a, 'gcx, 'tcx>)
947 -> &'tcx GenericParamDef
949 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
950 let param = &self.params[index as usize];
952 ty::GenericParamDefKind::Lifetime => param,
953 _ => bug!("expected lifetime parameter, but found another generic parameter")
956 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
957 .region_param(param, tcx)
961 /// Returns the `GenericParamDef` associated with this `ParamTy`.
962 pub fn type_param(&'tcx self,
964 tcx: TyCtxt<'a, 'gcx, 'tcx>)
965 -> &'tcx GenericParamDef {
966 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
967 let param = &self.params[index as usize];
969 ty::GenericParamDefKind::Type {..} => param,
970 _ => bug!("expected type parameter, but found another generic parameter")
973 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
974 .type_param(param, tcx)
979 /// Bounds on generics.
980 #[derive(Clone, Default)]
981 pub struct GenericPredicates<'tcx> {
982 pub parent: Option<DefId>,
983 pub predicates: Vec<(Predicate<'tcx>, Span)>,
986 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
987 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
989 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
990 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
991 -> InstantiatedPredicates<'tcx> {
992 let mut instantiated = InstantiatedPredicates::empty();
993 self.instantiate_into(tcx, &mut instantiated, substs);
996 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
997 -> InstantiatedPredicates<'tcx> {
998 InstantiatedPredicates {
999 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1003 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1004 instantiated: &mut InstantiatedPredicates<'tcx>,
1005 substs: &Substs<'tcx>) {
1006 if let Some(def_id) = self.parent {
1007 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1009 instantiated.predicates.extend(
1010 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1014 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1015 -> InstantiatedPredicates<'tcx> {
1016 let mut instantiated = InstantiatedPredicates::empty();
1017 self.instantiate_identity_into(tcx, &mut instantiated);
1021 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1022 instantiated: &mut InstantiatedPredicates<'tcx>) {
1023 if let Some(def_id) = self.parent {
1024 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1026 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1029 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1030 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1031 -> InstantiatedPredicates<'tcx>
1033 assert_eq!(self.parent, None);
1034 InstantiatedPredicates {
1035 predicates: self.predicates.iter().map(|(pred, _)| {
1036 pred.subst_supertrait(tcx, poly_trait_ref)
1042 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1043 pub enum Predicate<'tcx> {
1044 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
1045 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1046 /// would be the type parameters.
1047 Trait(PolyTraitPredicate<'tcx>),
1050 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1053 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1055 /// where `<T as TraitRef>::Name == X`, approximately.
1056 /// See the `ProjectionPredicate` struct for details.
1057 Projection(PolyProjectionPredicate<'tcx>),
1059 /// no syntax: `T` well-formed
1060 WellFormed(Ty<'tcx>),
1062 /// trait must be object-safe
1065 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
1066 /// for some substitutions `...` and `T` being a closure type.
1067 /// Satisfied (or refuted) once we know the closure's kind.
1068 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1071 Subtype(PolySubtypePredicate<'tcx>),
1073 /// Constant initializer must evaluate successfully.
1074 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1077 /// The crate outlives map is computed during typeck and contains the
1078 /// outlives of every item in the local crate. You should not use it
1079 /// directly, because to do so will make your pass dependent on the
1080 /// HIR of every item in the local crate. Instead, use
1081 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1083 pub struct CratePredicatesMap<'tcx> {
1084 /// For each struct with outlive bounds, maps to a vector of the
1085 /// predicate of its outlive bounds. If an item has no outlives
1086 /// bounds, it will have no entry.
1087 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1089 /// An empty vector, useful for cloning.
1090 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1093 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1094 fn as_ref(&self) -> &Predicate<'tcx> {
1099 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1100 /// Performs a substitution suitable for going from a
1101 /// poly-trait-ref to supertraits that must hold if that
1102 /// poly-trait-ref holds. This is slightly different from a normal
1103 /// substitution in terms of what happens with bound regions. See
1104 /// lengthy comment below for details.
1105 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1106 trait_ref: &ty::PolyTraitRef<'tcx>)
1107 -> ty::Predicate<'tcx>
1109 // The interaction between HRTB and supertraits is not entirely
1110 // obvious. Let me walk you (and myself) through an example.
1112 // Let's start with an easy case. Consider two traits:
1114 // trait Foo<'a> : Bar<'a,'a> { }
1115 // trait Bar<'b,'c> { }
1117 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1118 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1119 // knew that `Foo<'x>` (for any 'x) then we also know that
1120 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1121 // normal substitution.
1123 // In terms of why this is sound, the idea is that whenever there
1124 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1125 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1126 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1129 // Another example to be careful of is this:
1131 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1132 // trait Bar1<'b,'c> { }
1134 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1135 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1136 // reason is similar to the previous example: any impl of
1137 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1138 // basically we would want to collapse the bound lifetimes from
1139 // the input (`trait_ref`) and the supertraits.
1141 // To achieve this in practice is fairly straightforward. Let's
1142 // consider the more complicated scenario:
1144 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1145 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1146 // where both `'x` and `'b` would have a DB index of 1.
1147 // The substitution from the input trait-ref is therefore going to be
1148 // `'a => 'x` (where `'x` has a DB index of 1).
1149 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1150 // early-bound parameter and `'b' is a late-bound parameter with a
1152 // - If we replace `'a` with `'x` from the input, it too will have
1153 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1154 // just as we wanted.
1156 // There is only one catch. If we just apply the substitution `'a
1157 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1158 // adjust the DB index because we substituting into a binder (it
1159 // tries to be so smart...) resulting in `for<'x> for<'b>
1160 // Bar1<'x,'b>` (we have no syntax for this, so use your
1161 // imagination). Basically the 'x will have DB index of 2 and 'b
1162 // will have DB index of 1. Not quite what we want. So we apply
1163 // the substitution to the *contents* of the trait reference,
1164 // rather than the trait reference itself (put another way, the
1165 // substitution code expects equal binding levels in the values
1166 // from the substitution and the value being substituted into, and
1167 // this trick achieves that).
1169 let substs = &trait_ref.skip_binder().substs;
1171 Predicate::Trait(ref binder) =>
1172 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1173 Predicate::Subtype(ref binder) =>
1174 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1175 Predicate::RegionOutlives(ref binder) =>
1176 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1177 Predicate::TypeOutlives(ref binder) =>
1178 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1179 Predicate::Projection(ref binder) =>
1180 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1181 Predicate::WellFormed(data) =>
1182 Predicate::WellFormed(data.subst(tcx, substs)),
1183 Predicate::ObjectSafe(trait_def_id) =>
1184 Predicate::ObjectSafe(trait_def_id),
1185 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1186 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1187 Predicate::ConstEvaluatable(def_id, const_substs) =>
1188 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1193 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1194 pub struct TraitPredicate<'tcx> {
1195 pub trait_ref: TraitRef<'tcx>
1197 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1199 impl<'tcx> TraitPredicate<'tcx> {
1200 pub fn def_id(&self) -> DefId {
1201 self.trait_ref.def_id
1204 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1205 self.trait_ref.input_types()
1208 pub fn self_ty(&self) -> Ty<'tcx> {
1209 self.trait_ref.self_ty()
1213 impl<'tcx> PolyTraitPredicate<'tcx> {
1214 pub fn def_id(&self) -> DefId {
1215 // ok to skip binder since trait def-id does not care about regions
1216 self.skip_binder().def_id()
1220 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1221 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1222 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1223 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1225 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1227 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1228 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1230 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1231 pub struct SubtypePredicate<'tcx> {
1232 pub a_is_expected: bool,
1236 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1238 /// This kind of predicate has no *direct* correspondent in the
1239 /// syntax, but it roughly corresponds to the syntactic forms:
1241 /// 1. `T : TraitRef<..., Item=Type>`
1242 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1244 /// In particular, form #1 is "desugared" to the combination of a
1245 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1246 /// predicates. Form #2 is a broader form in that it also permits
1247 /// equality between arbitrary types. Processing an instance of
1248 /// Form #2 eventually yields one of these `ProjectionPredicate`
1249 /// instances to normalize the LHS.
1250 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1251 pub struct ProjectionPredicate<'tcx> {
1252 pub projection_ty: ProjectionTy<'tcx>,
1256 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1258 impl<'tcx> PolyProjectionPredicate<'tcx> {
1259 /// Returns the def-id of the associated item being projected.
1260 pub fn item_def_id(&self) -> DefId {
1261 self.skip_binder().projection_ty.item_def_id
1264 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1265 // Note: unlike with TraitRef::to_poly_trait_ref(),
1266 // self.0.trait_ref is permitted to have escaping regions.
1267 // This is because here `self` has a `Binder` and so does our
1268 // return value, so we are preserving the number of binding
1270 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1273 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1274 self.map_bound(|predicate| predicate.ty)
1277 /// The DefId of the TraitItem for the associated type.
1279 /// Note that this is not the DefId of the TraitRef containing this
1280 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1281 pub fn projection_def_id(&self) -> DefId {
1282 // ok to skip binder since trait def-id does not care about regions
1283 self.skip_binder().projection_ty.item_def_id
1287 pub trait ToPolyTraitRef<'tcx> {
1288 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1291 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1292 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1293 ty::Binder::dummy(self.clone())
1297 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1298 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1299 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1303 pub trait ToPredicate<'tcx> {
1304 fn to_predicate(&self) -> Predicate<'tcx>;
1307 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1308 fn to_predicate(&self) -> Predicate<'tcx> {
1309 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1310 trait_ref: self.clone()
1315 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1316 fn to_predicate(&self) -> Predicate<'tcx> {
1317 ty::Predicate::Trait(self.to_poly_trait_predicate())
1321 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1322 fn to_predicate(&self) -> Predicate<'tcx> {
1323 Predicate::RegionOutlives(self.clone())
1327 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1328 fn to_predicate(&self) -> Predicate<'tcx> {
1329 Predicate::TypeOutlives(self.clone())
1333 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1334 fn to_predicate(&self) -> Predicate<'tcx> {
1335 Predicate::Projection(self.clone())
1339 impl<'tcx> Predicate<'tcx> {
1340 /// Iterates over the types in this predicate. Note that in all
1341 /// cases this is skipping over a binder, so late-bound regions
1342 /// with depth 0 are bound by the predicate.
1343 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1344 let vec: Vec<_> = match *self {
1345 ty::Predicate::Trait(ref data) => {
1346 data.skip_binder().input_types().collect()
1348 ty::Predicate::Subtype(binder) => {
1349 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1352 ty::Predicate::TypeOutlives(binder) => {
1353 vec![binder.skip_binder().0]
1355 ty::Predicate::RegionOutlives(..) => {
1358 ty::Predicate::Projection(ref data) => {
1359 let inner = data.skip_binder();
1360 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1362 ty::Predicate::WellFormed(data) => {
1365 ty::Predicate::ObjectSafe(_trait_def_id) => {
1368 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1369 closure_substs.substs.types().collect()
1371 ty::Predicate::ConstEvaluatable(_, substs) => {
1372 substs.types().collect()
1376 // FIXME: The only reason to collect into a vector here is that I was
1377 // too lazy to make the full (somewhat complicated) iterator
1378 // type that would be needed here. But I wanted this fn to
1379 // return an iterator conceptually, rather than a `Vec`, so as
1380 // to be closer to `Ty::walk`.
1384 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1386 Predicate::Trait(ref t) => {
1387 Some(t.to_poly_trait_ref())
1389 Predicate::Projection(..) |
1390 Predicate::Subtype(..) |
1391 Predicate::RegionOutlives(..) |
1392 Predicate::WellFormed(..) |
1393 Predicate::ObjectSafe(..) |
1394 Predicate::ClosureKind(..) |
1395 Predicate::TypeOutlives(..) |
1396 Predicate::ConstEvaluatable(..) => {
1402 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1404 Predicate::TypeOutlives(data) => {
1407 Predicate::Trait(..) |
1408 Predicate::Projection(..) |
1409 Predicate::Subtype(..) |
1410 Predicate::RegionOutlives(..) |
1411 Predicate::WellFormed(..) |
1412 Predicate::ObjectSafe(..) |
1413 Predicate::ClosureKind(..) |
1414 Predicate::ConstEvaluatable(..) => {
1421 /// Represents the bounds declared on a particular set of type
1422 /// parameters. Should eventually be generalized into a flag list of
1423 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1424 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1425 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1426 /// the `GenericPredicates` are expressed in terms of the bound type
1427 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1428 /// represented a set of bounds for some particular instantiation,
1429 /// meaning that the generic parameters have been substituted with
1434 /// struct Foo<T,U:Bar<T>> { ... }
1436 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1437 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1438 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1439 /// [usize:Bar<isize>]]`.
1441 pub struct InstantiatedPredicates<'tcx> {
1442 pub predicates: Vec<Predicate<'tcx>>,
1445 impl<'tcx> InstantiatedPredicates<'tcx> {
1446 pub fn empty() -> InstantiatedPredicates<'tcx> {
1447 InstantiatedPredicates { predicates: vec![] }
1450 pub fn is_empty(&self) -> bool {
1451 self.predicates.is_empty()
1455 /// "Universes" are used during type- and trait-checking in the
1456 /// presence of `for<..>` binders to control what sets of names are
1457 /// visible. Universes are arranged into a tree: the root universe
1458 /// contains names that are always visible. Each child then adds a new
1459 /// set of names that are visible, in addition to those of its parent.
1460 /// We say that the child universe "extends" the parent universe with
1463 /// To make this more concrete, consider this program:
1467 /// fn bar<T>(x: T) {
1468 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1472 /// The struct name `Foo` is in the root universe U0. But the type
1473 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1474 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1475 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1476 /// region `'a` is in a universe U2 that extends U1, because we can
1477 /// name it inside the fn type but not outside.
1479 /// Universes are used to do type- and trait-checking around these
1480 /// "forall" binders (also called **universal quantification**). The
1481 /// idea is that when, in the body of `bar`, we refer to `T` as a
1482 /// type, we aren't referring to any type in particular, but rather a
1483 /// kind of "fresh" type that is distinct from all other types we have
1484 /// actually declared. This is called a **placeholder** type, and we
1485 /// use universes to talk about this. In other words, a type name in
1486 /// universe 0 always corresponds to some "ground" type that the user
1487 /// declared, but a type name in a non-zero universe is a placeholder
1488 /// type -- an idealized representative of "types in general" that we
1489 /// use for checking generic functions.
1491 pub struct UniverseIndex {
1492 DEBUG_FORMAT = "U{}",
1496 impl_stable_hash_for!(struct UniverseIndex { private });
1498 impl UniverseIndex {
1499 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1501 /// Returns the "next" universe index in order -- this new index
1502 /// is considered to extend all previous universes. This
1503 /// corresponds to entering a `forall` quantifier. So, for
1504 /// example, suppose we have this type in universe `U`:
1507 /// for<'a> fn(&'a u32)
1510 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1511 /// new universe that extends `U` -- in this new universe, we can
1512 /// name the region `'a`, but that region was not nameable from
1513 /// `U` because it was not in scope there.
1514 pub fn next_universe(self) -> UniverseIndex {
1515 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1518 /// True if `self` can name a name from `other` -- in other words,
1519 /// if the set of names in `self` is a superset of those in
1520 /// `other` (`self >= other`).
1521 pub fn can_name(self, other: UniverseIndex) -> bool {
1522 self.private >= other.private
1525 /// True if `self` cannot name some names from `other` -- in other
1526 /// words, if the set of names in `self` is a strict subset of
1527 /// those in `other` (`self < other`).
1528 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1529 self.private < other.private
1533 /// The "placeholder index" fully defines a placeholder region.
1534 /// Placeholder regions are identified by both a **universe** as well
1535 /// as a "bound-region" within that universe. The `bound_region` is
1536 /// basically a name -- distinct bound regions within the same
1537 /// universe are just two regions with an unknown relationship to one
1539 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1540 pub struct Placeholder {
1541 pub universe: UniverseIndex,
1542 pub name: BoundRegion,
1545 impl_stable_hash_for!(struct Placeholder { universe, name });
1547 /// When type checking, we use the `ParamEnv` to track
1548 /// details about the set of where-clauses that are in scope at this
1549 /// particular point.
1550 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1551 pub struct ParamEnv<'tcx> {
1552 /// Obligations that the caller must satisfy. This is basically
1553 /// the set of bounds on the in-scope type parameters, translated
1554 /// into Obligations, and elaborated and normalized.
1555 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1557 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1558 /// want `Reveal::All` -- note that this is always paired with an
1559 /// empty environment. To get that, use `ParamEnv::reveal()`.
1560 pub reveal: traits::Reveal,
1563 impl<'tcx> ParamEnv<'tcx> {
1564 /// Construct a trait environment suitable for contexts where
1565 /// there are no where clauses in scope. Hidden types (like `impl
1566 /// Trait`) are left hidden, so this is suitable for ordinary
1568 pub fn empty() -> Self {
1569 Self::new(List::empty(), Reveal::UserFacing)
1572 /// Construct a trait environment with no where clauses in scope
1573 /// where the values of all `impl Trait` and other hidden types
1574 /// are revealed. This is suitable for monomorphized, post-typeck
1575 /// environments like codegen or doing optimizations.
1577 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1578 /// or invoke `param_env.with_reveal_all()`.
1579 pub fn reveal_all() -> Self {
1580 Self::new(List::empty(), Reveal::All)
1583 /// Construct a trait environment with the given set of predicates.
1584 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1587 ty::ParamEnv { caller_bounds, reveal }
1590 /// Returns a new parameter environment with the same clauses, but
1591 /// which "reveals" the true results of projections in all cases
1592 /// (even for associated types that are specializable). This is
1593 /// the desired behavior during codegen and certain other special
1594 /// contexts; normally though we want to use `Reveal::UserFacing`,
1595 /// which is the default.
1596 pub fn with_reveal_all(self) -> Self {
1597 ty::ParamEnv { reveal: Reveal::All, ..self }
1600 /// Returns this same environment but with no caller bounds.
1601 pub fn without_caller_bounds(self) -> Self {
1602 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1605 /// Creates a suitable environment in which to perform trait
1606 /// queries on the given value. When type-checking, this is simply
1607 /// the pair of the environment plus value. But when reveal is set to
1608 /// All, then if `value` does not reference any type parameters, we will
1609 /// pair it with the empty environment. This improves caching and is generally
1612 /// NB: We preserve the environment when type-checking because it
1613 /// is possible for the user to have wacky where-clauses like
1614 /// `where Box<u32>: Copy`, which are clearly never
1615 /// satisfiable. We generally want to behave as if they were true,
1616 /// although the surrounding function is never reachable.
1617 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1619 Reveal::UserFacing => {
1628 || value.needs_infer()
1629 || value.has_param_types()
1630 || value.has_self_ty()
1638 param_env: self.without_caller_bounds(),
1647 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1648 pub struct ParamEnvAnd<'tcx, T> {
1649 pub param_env: ParamEnv<'tcx>,
1653 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1654 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1655 (self.param_env, self.value)
1659 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1660 where T: HashStable<StableHashingContext<'a>>
1662 fn hash_stable<W: StableHasherResult>(&self,
1663 hcx: &mut StableHashingContext<'a>,
1664 hasher: &mut StableHasher<W>) {
1670 param_env.hash_stable(hcx, hasher);
1671 value.hash_stable(hcx, hasher);
1675 #[derive(Copy, Clone, Debug)]
1676 pub struct Destructor {
1677 /// The def-id of the destructor method
1682 pub struct AdtFlags: u32 {
1683 const NO_ADT_FLAGS = 0;
1684 const IS_ENUM = 1 << 0;
1685 const IS_PHANTOM_DATA = 1 << 1;
1686 const IS_FUNDAMENTAL = 1 << 2;
1687 const IS_UNION = 1 << 3;
1688 const IS_BOX = 1 << 4;
1689 /// Indicates whether the type is an `Arc`.
1690 const IS_ARC = 1 << 5;
1691 /// Indicates whether the type is an `Rc`.
1692 const IS_RC = 1 << 6;
1693 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1694 /// (i.e., this flag is never set unless this ADT is an enum).
1695 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 7;
1700 pub struct VariantFlags: u32 {
1701 const NO_VARIANT_FLAGS = 0;
1702 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1703 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1708 pub struct VariantDef {
1709 /// The variant's DefId. If this is a tuple-like struct,
1710 /// this is the DefId of the struct's ctor.
1712 pub name: Name, // struct's name if this is a struct
1713 pub discr: VariantDiscr,
1714 pub fields: Vec<FieldDef>,
1715 pub ctor_kind: CtorKind,
1716 flags: VariantFlags,
1719 impl<'a, 'gcx, 'tcx> VariantDef {
1720 /// Create a new `VariantDef`.
1722 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1723 /// and for everything else, it is the variant DefId.
1724 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1725 /// this is the struct DefId for structs, and the variant DefId for variants.
1727 /// Note that we *could* use the constructor DefId, because the constructor attributes
1728 /// redirect to the base attributes, but compiling a small crate requires
1729 /// loading the AdtDefs for all the structs in the universe (e.g. coherence for any
1730 /// built-in trait), and we do not want to load attributes twice.
1732 /// If someone speeds up attribute loading to not be a performance concern, they can
1733 /// remove this hack and use the constructor DefId everywhere.
1734 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1737 discr: VariantDiscr,
1738 fields: Vec<FieldDef>,
1740 ctor_kind: CtorKind,
1741 attribute_def_id: DefId)
1744 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1745 fields, adt_kind, ctor_kind, attribute_def_id);
1746 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1747 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1748 debug!("found non-exhaustive field list for {:?}", did);
1749 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1762 pub fn is_field_list_non_exhaustive(&self) -> bool {
1763 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1767 impl_stable_hash_for!(struct VariantDef {
1776 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1777 pub enum VariantDiscr {
1778 /// Explicit value for this variant, i.e. `X = 123`.
1779 /// The `DefId` corresponds to the embedded constant.
1782 /// The previous variant's discriminant plus one.
1783 /// For efficiency reasons, the distance from the
1784 /// last `Explicit` discriminant is being stored,
1785 /// or `0` for the first variant, if it has none.
1790 pub struct FieldDef {
1793 pub vis: Visibility,
1796 /// The definition of an abstract data type - a struct or enum.
1798 /// These are all interned (by intern_adt_def) into the adt_defs
1802 pub variants: Vec<VariantDef>,
1804 pub repr: ReprOptions,
1807 impl PartialOrd for AdtDef {
1808 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1809 Some(self.cmp(&other))
1813 /// There should be only one AdtDef for each `did`, therefore
1814 /// it is fine to implement `Ord` only based on `did`.
1815 impl Ord for AdtDef {
1816 fn cmp(&self, other: &AdtDef) -> Ordering {
1817 self.did.cmp(&other.did)
1821 impl PartialEq for AdtDef {
1822 // AdtDef are always interned and this is part of TyS equality
1824 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1827 impl Eq for AdtDef {}
1829 impl Hash for AdtDef {
1831 fn hash<H: Hasher>(&self, s: &mut H) {
1832 (self as *const AdtDef).hash(s)
1836 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1837 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1842 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1845 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1846 fn hash_stable<W: StableHasherResult>(&self,
1847 hcx: &mut StableHashingContext<'a>,
1848 hasher: &mut StableHasher<W>) {
1850 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1853 let hash: Fingerprint = CACHE.with(|cache| {
1854 let addr = self as *const AdtDef as usize;
1855 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1863 let mut hasher = StableHasher::new();
1864 did.hash_stable(hcx, &mut hasher);
1865 variants.hash_stable(hcx, &mut hasher);
1866 flags.hash_stable(hcx, &mut hasher);
1867 repr.hash_stable(hcx, &mut hasher);
1873 hash.hash_stable(hcx, hasher);
1877 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1878 pub enum AdtKind { Struct, Union, Enum }
1880 impl Into<DataTypeKind> for AdtKind {
1881 fn into(self) -> DataTypeKind {
1883 AdtKind::Struct => DataTypeKind::Struct,
1884 AdtKind::Union => DataTypeKind::Union,
1885 AdtKind::Enum => DataTypeKind::Enum,
1891 #[derive(RustcEncodable, RustcDecodable, Default)]
1892 pub struct ReprFlags: u8 {
1893 const IS_C = 1 << 0;
1894 const IS_SIMD = 1 << 1;
1895 const IS_TRANSPARENT = 1 << 2;
1896 // Internal only for now. If true, don't reorder fields.
1897 const IS_LINEAR = 1 << 3;
1899 // Any of these flags being set prevent field reordering optimisation.
1900 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1901 ReprFlags::IS_SIMD.bits |
1902 ReprFlags::IS_LINEAR.bits;
1906 impl_stable_hash_for!(struct ReprFlags {
1912 /// Represents the repr options provided by the user,
1913 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1914 pub struct ReprOptions {
1915 pub int: Option<attr::IntType>,
1918 pub flags: ReprFlags,
1921 impl_stable_hash_for!(struct ReprOptions {
1929 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
1930 let mut flags = ReprFlags::empty();
1931 let mut size = None;
1932 let mut max_align = 0;
1933 let mut min_pack = 0;
1934 for attr in tcx.get_attrs(did).iter() {
1935 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
1936 flags.insert(match r {
1937 attr::ReprC => ReprFlags::IS_C,
1938 attr::ReprPacked(pack) => {
1939 min_pack = if min_pack > 0 {
1940 cmp::min(pack, min_pack)
1946 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1947 attr::ReprSimd => ReprFlags::IS_SIMD,
1948 attr::ReprInt(i) => {
1952 attr::ReprAlign(align) => {
1953 max_align = cmp::max(align, max_align);
1960 // This is here instead of layout because the choice must make it into metadata.
1961 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1962 flags.insert(ReprFlags::IS_LINEAR);
1964 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1968 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1970 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1972 pub fn packed(&self) -> bool { self.pack > 0 }
1974 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1976 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1978 pub fn discr_type(&self) -> attr::IntType {
1979 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1982 /// Returns true if this `#[repr()]` should inhabit "smart enum
1983 /// layout" optimizations, such as representing `Foo<&T>` as a
1985 pub fn inhibit_enum_layout_opt(&self) -> bool {
1986 self.c() || self.int.is_some()
1989 /// Returns true if this `#[repr()]` should inhibit struct field reordering
1990 /// optimizations, such as with repr(C) or repr(packed(1)).
1991 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1992 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1996 impl<'a, 'gcx, 'tcx> AdtDef {
1997 fn new(tcx: TyCtxt<'_, '_, '_>,
2000 variants: Vec<VariantDef>,
2001 repr: ReprOptions) -> Self {
2002 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2003 let mut flags = AdtFlags::NO_ADT_FLAGS;
2004 let attrs = tcx.get_attrs(did);
2005 if attr::contains_name(&attrs, "fundamental") {
2006 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2008 if Some(did) == tcx.lang_items().phantom_data() {
2009 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2011 if Some(did) == tcx.lang_items().owned_box() {
2012 flags = flags | AdtFlags::IS_BOX;
2014 if Some(did) == tcx.lang_items().arc() {
2015 flags = flags | AdtFlags::IS_ARC;
2017 if Some(did) == tcx.lang_items().rc() {
2018 flags = flags | AdtFlags::IS_RC;
2020 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2021 debug!("found non-exhaustive variant list for {:?}", did);
2022 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2025 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2026 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2027 AdtKind::Struct => {}
2038 pub fn is_struct(&self) -> bool {
2039 !self.is_union() && !self.is_enum()
2043 pub fn is_union(&self) -> bool {
2044 self.flags.intersects(AdtFlags::IS_UNION)
2048 pub fn is_enum(&self) -> bool {
2049 self.flags.intersects(AdtFlags::IS_ENUM)
2053 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2054 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2057 /// Returns the kind of the ADT - Struct or Enum.
2059 pub fn adt_kind(&self) -> AdtKind {
2062 } else if self.is_union() {
2069 pub fn descr(&self) -> &'static str {
2070 match self.adt_kind() {
2071 AdtKind::Struct => "struct",
2072 AdtKind::Union => "union",
2073 AdtKind::Enum => "enum",
2077 pub fn variant_descr(&self) -> &'static str {
2078 match self.adt_kind() {
2079 AdtKind::Struct => "struct",
2080 AdtKind::Union => "union",
2081 AdtKind::Enum => "variant",
2085 /// Returns whether this type is #[fundamental] for the purposes
2086 /// of coherence checking.
2088 pub fn is_fundamental(&self) -> bool {
2089 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2092 /// Returns true if this is PhantomData<T>.
2094 pub fn is_phantom_data(&self) -> bool {
2095 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
2098 /// Returns `true` if this is `Arc<T>`.
2099 pub fn is_arc(&self) -> bool {
2100 self.flags.intersects(AdtFlags::IS_ARC)
2103 /// Returns `true` if this is `Rc<T>`.
2104 pub fn is_rc(&self) -> bool {
2105 self.flags.intersects(AdtFlags::IS_RC)
2108 /// Returns true if this is Box<T>.
2110 pub fn is_box(&self) -> bool {
2111 self.flags.intersects(AdtFlags::IS_BOX)
2114 /// Returns whether this type has a destructor.
2115 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2116 self.destructor(tcx).is_some()
2119 /// Asserts this is a struct or union and returns its unique variant.
2120 pub fn non_enum_variant(&self) -> &VariantDef {
2121 assert!(self.is_struct() || self.is_union());
2126 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
2127 tcx.predicates_of(self.did)
2130 /// Returns an iterator over all fields contained
2133 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2134 self.variants.iter().flat_map(|v| v.fields.iter())
2137 pub fn is_payloadfree(&self) -> bool {
2138 !self.variants.is_empty() &&
2139 self.variants.iter().all(|v| v.fields.is_empty())
2142 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2145 .find(|v| v.did == vid)
2146 .expect("variant_with_id: unknown variant")
2149 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
2152 .position(|v| v.did == vid)
2153 .expect("variant_index_with_id: unknown variant")
2156 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2158 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2159 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2160 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2161 Def::SelfCtor(..) => self.non_enum_variant(),
2162 _ => bug!("unexpected def {:?} in variant_of_def", def)
2167 pub fn eval_explicit_discr(
2169 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2171 ) -> Option<Discr<'tcx>> {
2172 let param_env = ParamEnv::empty();
2173 let repr_type = self.repr.discr_type();
2174 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2175 let instance = ty::Instance::new(expr_did, substs);
2176 let cid = GlobalId {
2180 match tcx.const_eval(param_env.and(cid)) {
2182 // FIXME: Find the right type and use it instead of `val.ty` here
2183 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2184 trace!("discriminants: {} ({:?})", b, repr_type);
2190 info!("invalid enum discriminant: {:#?}", val);
2191 ::mir::interpret::struct_error(
2192 tcx.at(tcx.def_span(expr_did)),
2193 "constant evaluation of enum discriminant resulted in non-integer",
2198 Err(ErrorHandled::Reported) => {
2199 if !expr_did.is_local() {
2200 span_bug!(tcx.def_span(expr_did),
2201 "variant discriminant evaluation succeeded \
2202 in its crate but failed locally");
2206 Err(ErrorHandled::TooGeneric) => span_bug!(
2207 tcx.def_span(expr_did),
2208 "enum discriminant depends on generic arguments",
2214 pub fn discriminants(
2216 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2217 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
2218 let repr_type = self.repr.discr_type();
2219 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2220 let mut prev_discr = None::<Discr<'tcx>>;
2221 self.variants.iter().map(move |v| {
2222 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2223 if let VariantDiscr::Explicit(expr_did) = v.discr {
2224 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2228 prev_discr = Some(discr);
2234 /// Compute the discriminant value used by a specific variant.
2235 /// Unlike `discriminants`, this is (amortized) constant-time,
2236 /// only doing at most one query for evaluating an explicit
2237 /// discriminant (the last one before the requested variant),
2238 /// assuming there are no constant-evaluation errors there.
2239 pub fn discriminant_for_variant(&self,
2240 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2241 variant_index: usize)
2243 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2244 let explicit_value = val
2245 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2246 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2247 explicit_value.checked_add(tcx, offset as u128).0
2250 /// Yields a DefId for the discriminant and an offset to add to it
2251 /// Alternatively, if there is no explicit discriminant, returns the
2252 /// inferred discriminant directly
2253 pub fn discriminant_def_for_variant(
2255 variant_index: usize,
2256 ) -> (Option<DefId>, usize) {
2257 let mut explicit_index = variant_index;
2260 match self.variants[explicit_index].discr {
2261 ty::VariantDiscr::Relative(0) => {
2265 ty::VariantDiscr::Relative(distance) => {
2266 explicit_index -= distance;
2268 ty::VariantDiscr::Explicit(did) => {
2269 expr_did = Some(did);
2274 (expr_did, variant_index - explicit_index)
2277 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2278 tcx.adt_destructor(self.did)
2281 /// Returns a list of types such that `Self: Sized` if and only
2282 /// if that type is Sized, or `TyErr` if this type is recursive.
2284 /// Oddly enough, checking that the sized-constraint is Sized is
2285 /// actually more expressive than checking all members:
2286 /// the Sized trait is inductive, so an associated type that references
2287 /// Self would prevent its containing ADT from being Sized.
2289 /// Due to normalization being eager, this applies even if
2290 /// the associated type is behind a pointer, e.g. issue #31299.
2291 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2292 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2295 debug!("adt_sized_constraint: {:?} is recursive", self);
2296 // This should be reported as an error by `check_representable`.
2298 // Consider the type as Sized in the meanwhile to avoid
2299 // further errors. Delay our `bug` diagnostic here to get
2300 // emitted later as well in case we accidentally otherwise don't
2303 tcx.intern_type_list(&[tcx.types.err])
2308 fn sized_constraint_for_ty(&self,
2309 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2312 let result = match ty.sty {
2313 Bool | Char | Int(..) | Uint(..) | Float(..) |
2314 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2315 Array(..) | Closure(..) | Generator(..) | Never => {
2324 GeneratorWitness(..) => {
2325 // these are never sized - return the target type
2332 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2336 Adt(adt, substs) => {
2338 let adt_tys = adt.sized_constraint(tcx);
2339 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2342 .map(|ty| ty.subst(tcx, substs))
2343 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2347 Projection(..) | Opaque(..) => {
2348 // must calculate explicitly.
2349 // FIXME: consider special-casing always-Sized projections
2353 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2356 // perf hack: if there is a `T: Sized` bound, then
2357 // we know that `T` is Sized and do not need to check
2360 let sized_trait = match tcx.lang_items().sized_trait() {
2362 _ => return vec![ty]
2364 let sized_predicate = Binder::dummy(TraitRef {
2365 def_id: sized_trait,
2366 substs: tcx.mk_substs_trait(ty, &[])
2368 let predicates = tcx.predicates_of(self.did).predicates;
2369 if predicates.into_iter().any(|(p, _)| p == sized_predicate) {
2378 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2382 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2387 impl<'a, 'gcx, 'tcx> FieldDef {
2388 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2389 tcx.type_of(self.did).subst(tcx, subst)
2393 /// Represents the various closure traits in the Rust language. This
2394 /// will determine the type of the environment (`self`, in the
2395 /// desuaring) argument that the closure expects.
2397 /// You can get the environment type of a closure using
2398 /// `tcx.closure_env_ty()`.
2399 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2400 pub enum ClosureKind {
2401 // Warning: Ordering is significant here! The ordering is chosen
2402 // because the trait Fn is a subtrait of FnMut and so in turn, and
2403 // hence we order it so that Fn < FnMut < FnOnce.
2409 impl<'a, 'tcx> ClosureKind {
2410 // This is the initial value used when doing upvar inference.
2411 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2413 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2415 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2416 ClosureKind::FnMut => {
2417 tcx.require_lang_item(FnMutTraitLangItem)
2419 ClosureKind::FnOnce => {
2420 tcx.require_lang_item(FnOnceTraitLangItem)
2425 /// True if this a type that impls this closure kind
2426 /// must also implement `other`.
2427 pub fn extends(self, other: ty::ClosureKind) -> bool {
2428 match (self, other) {
2429 (ClosureKind::Fn, ClosureKind::Fn) => true,
2430 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2431 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2432 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2433 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2434 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2439 /// Returns the representative scalar type for this closure kind.
2440 /// See `TyS::to_opt_closure_kind` for more details.
2441 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2443 ty::ClosureKind::Fn => tcx.types.i8,
2444 ty::ClosureKind::FnMut => tcx.types.i16,
2445 ty::ClosureKind::FnOnce => tcx.types.i32,
2450 impl<'tcx> TyS<'tcx> {
2451 /// Iterator that walks `self` and any types reachable from
2452 /// `self`, in depth-first order. Note that just walks the types
2453 /// that appear in `self`, it does not descend into the fields of
2454 /// structs or variants. For example:
2457 /// isize => { isize }
2458 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2459 /// [isize] => { [isize], isize }
2461 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2462 TypeWalker::new(self)
2465 /// Iterator that walks the immediate children of `self`. Hence
2466 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2467 /// (but not `i32`, like `walk`).
2468 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2469 walk::walk_shallow(self)
2472 /// Walks `ty` and any types appearing within `ty`, invoking the
2473 /// callback `f` on each type. If the callback returns false, then the
2474 /// children of the current type are ignored.
2476 /// Note: prefer `ty.walk()` where possible.
2477 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2478 where F : FnMut(Ty<'tcx>) -> bool
2480 let mut walker = self.walk();
2481 while let Some(ty) = walker.next() {
2483 walker.skip_current_subtree();
2490 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2492 hir::MutMutable => MutBorrow,
2493 hir::MutImmutable => ImmBorrow,
2497 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2498 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2499 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2501 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2503 MutBorrow => hir::MutMutable,
2504 ImmBorrow => hir::MutImmutable,
2506 // We have no type corresponding to a unique imm borrow, so
2507 // use `&mut`. It gives all the capabilities of an `&uniq`
2508 // and hence is a safe "over approximation".
2509 UniqueImmBorrow => hir::MutMutable,
2513 pub fn to_user_str(&self) -> &'static str {
2515 MutBorrow => "mutable",
2516 ImmBorrow => "immutable",
2517 UniqueImmBorrow => "uniquely immutable",
2522 #[derive(Debug, Clone)]
2523 pub enum Attributes<'gcx> {
2524 Owned(Lrc<[ast::Attribute]>),
2525 Borrowed(&'gcx [ast::Attribute])
2528 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2529 type Target = [ast::Attribute];
2531 fn deref(&self) -> &[ast::Attribute] {
2533 &Attributes::Owned(ref data) => &data,
2534 &Attributes::Borrowed(data) => data
2539 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2540 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2541 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2544 /// Returns an iterator of the def-ids for all body-owners in this
2545 /// crate. If you would prefer to iterate over the bodies
2546 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2549 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2553 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2556 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2557 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2558 f(self.hir.body_owner_def_id(body_id))
2562 pub fn expr_span(self, id: NodeId) -> Span {
2563 match self.hir.find(id) {
2564 Some(Node::Expr(e)) => {
2568 bug!("Node id {} is not an expr: {:?}", id, f);
2571 bug!("Node id {} is not present in the node map", id);
2576 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2577 self.associated_items(id)
2578 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2582 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2583 self.associated_items(did).any(|item| {
2584 item.relevant_for_never()
2588 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2589 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2590 match self.hir.get(node_id) {
2591 Node::TraitItem(_) | Node::ImplItem(_) => true,
2595 match self.describe_def(def_id).expect("no def for def-id") {
2596 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2601 if is_associated_item {
2602 Some(self.associated_item(def_id))
2608 fn associated_item_from_trait_item_ref(self,
2609 parent_def_id: DefId,
2610 parent_vis: &hir::Visibility,
2611 trait_item_ref: &hir::TraitItemRef)
2613 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2614 let (kind, has_self) = match trait_item_ref.kind {
2615 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2616 hir::AssociatedItemKind::Method { has_self } => {
2617 (ty::AssociatedKind::Method, has_self)
2619 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2620 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2624 ident: trait_item_ref.ident,
2626 // Visibility of trait items is inherited from their traits.
2627 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2628 defaultness: trait_item_ref.defaultness,
2630 container: TraitContainer(parent_def_id),
2631 method_has_self_argument: has_self
2635 fn associated_item_from_impl_item_ref(self,
2636 parent_def_id: DefId,
2637 impl_item_ref: &hir::ImplItemRef)
2639 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2640 let (kind, has_self) = match impl_item_ref.kind {
2641 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2642 hir::AssociatedItemKind::Method { has_self } => {
2643 (ty::AssociatedKind::Method, has_self)
2645 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2646 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2650 ident: impl_item_ref.ident,
2652 // Visibility of trait impl items doesn't matter.
2653 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2654 defaultness: impl_item_ref.defaultness,
2656 container: ImplContainer(parent_def_id),
2657 method_has_self_argument: has_self
2661 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2662 let hir_id = self.hir.node_to_hir_id(node_id);
2663 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2666 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2667 variant.fields.iter().position(|field| {
2668 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2672 pub fn associated_items(
2675 ) -> impl Iterator<Item = AssociatedItem> + 'a {
2676 let def_ids = self.associated_item_def_ids(def_id);
2677 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2678 as Box<dyn Iterator<Item = AssociatedItem> + 'a>
2681 /// Returns true if the impls are the same polarity and the trait either
2682 /// has no items or is annotated #[marker] and prevents item overrides.
2683 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2684 if self.features().overlapping_marker_traits {
2685 let trait1_is_empty = self.impl_trait_ref(def_id1)
2686 .map_or(false, |trait_ref| {
2687 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2689 let trait2_is_empty = self.impl_trait_ref(def_id2)
2690 .map_or(false, |trait_ref| {
2691 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2693 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2696 } else if self.features().marker_trait_attr {
2697 let is_marker_impl = |def_id: DefId| -> bool {
2698 let trait_ref = self.impl_trait_ref(def_id);
2699 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2701 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2702 && is_marker_impl(def_id1)
2703 && is_marker_impl(def_id2)
2709 // Returns `ty::VariantDef` if `def` refers to a struct,
2710 // or variant or their constructors, panics otherwise.
2711 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2713 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2714 let enum_did = self.parent_def_id(did).unwrap();
2715 self.adt_def(enum_did).variant_with_id(did)
2717 Def::Struct(did) | Def::Union(did) => {
2718 self.adt_def(did).non_enum_variant()
2720 Def::StructCtor(ctor_did, ..) => {
2721 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2722 self.adt_def(did).non_enum_variant()
2724 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2728 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2729 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2730 let def_key = self.def_key(variant_def.did);
2731 match def_key.disambiguated_data.data {
2732 // for enum variants and tuple structs, the def-id of the ADT itself
2733 // is the *parent* of the variant
2734 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2735 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2737 // otherwise, for structs and unions, they share a def-id
2738 _ => variant_def.did,
2742 pub fn item_name(self, id: DefId) -> InternedString {
2743 if id.index == CRATE_DEF_INDEX {
2744 self.original_crate_name(id.krate).as_interned_str()
2746 let def_key = self.def_key(id);
2747 // The name of a StructCtor is that of its struct parent.
2748 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2749 self.item_name(DefId {
2751 index: def_key.parent.unwrap()
2754 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2755 bug!("item_name: no name for {:?}", self.def_path(id));
2761 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2762 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2766 ty::InstanceDef::Item(did) => {
2767 self.optimized_mir(did)
2769 ty::InstanceDef::VtableShim(..) |
2770 ty::InstanceDef::Intrinsic(..) |
2771 ty::InstanceDef::FnPtrShim(..) |
2772 ty::InstanceDef::Virtual(..) |
2773 ty::InstanceDef::ClosureOnceShim { .. } |
2774 ty::InstanceDef::DropGlue(..) |
2775 ty::InstanceDef::CloneShim(..) => {
2776 self.mir_shims(instance)
2781 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2782 /// Returns None if there is no MIR for the DefId
2783 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2784 if self.is_mir_available(did) {
2785 Some(self.optimized_mir(did))
2791 /// Get the attributes of a definition.
2792 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2793 if let Some(id) = self.hir.as_local_node_id(did) {
2794 Attributes::Borrowed(self.hir.attrs(id))
2796 Attributes::Owned(self.item_attrs(did))
2800 /// Determine whether an item is annotated with an attribute.
2801 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2802 attr::contains_name(&self.get_attrs(did), attr)
2805 /// Returns true if this is an `auto trait`.
2806 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2807 self.trait_def(trait_def_id).has_auto_impl
2810 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2811 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2814 /// Given the def-id of an impl, return the def_id of the trait it implements.
2815 /// If it implements no trait, return `None`.
2816 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2817 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2820 /// If the given defid describes a method belonging to an impl, return the
2821 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2822 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2823 let item = if def_id.krate != LOCAL_CRATE {
2824 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2825 Some(self.associated_item(def_id))
2830 self.opt_associated_item(def_id)
2833 item.and_then(|trait_item|
2834 match trait_item.container {
2835 TraitContainer(_) => None,
2836 ImplContainer(def_id) => Some(def_id),
2841 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2842 /// with the name of the crate containing the impl.
2843 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2844 if impl_did.is_local() {
2845 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2846 Ok(self.hir.span(node_id))
2848 Err(self.crate_name(impl_did.krate))
2852 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2853 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2854 // definition's parent/scope to perform comparison.
2855 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2856 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2859 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2860 ident = ident.modern();
2861 let target_expansion = match scope.krate {
2862 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2865 let scope = match ident.span.adjust(target_expansion) {
2866 Some(actual_expansion) =>
2867 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2868 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2869 None => self.hir.get_module_parent(block),
2875 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2876 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2877 F: FnOnce(&[hir::Freevar]) -> T,
2879 let def_id = self.hir.local_def_id(fid);
2880 match self.freevars(def_id) {
2887 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
2888 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2889 let parent_id = tcx.hir.get_parent(id);
2890 let parent_def_id = tcx.hir.local_def_id(parent_id);
2891 let parent_item = tcx.hir.expect_item(parent_id);
2892 match parent_item.node {
2893 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2894 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2895 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2897 debug_assert_eq!(assoc_item.def_id, def_id);
2902 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2903 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2904 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2907 debug_assert_eq!(assoc_item.def_id, def_id);
2915 span_bug!(parent_item.span,
2916 "unexpected parent of trait or impl item or item not found: {:?}",
2920 /// Calculates the Sized-constraint.
2922 /// In fact, there are only a few options for the types in the constraint:
2923 /// - an obviously-unsized type
2924 /// - a type parameter or projection whose Sizedness can't be known
2925 /// - a tuple of type parameters or projections, if there are multiple
2927 /// - a Error, if a type contained itself. The representability
2928 /// check should catch this case.
2929 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2931 -> &'tcx [Ty<'tcx>] {
2932 let def = tcx.adt_def(def_id);
2934 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
2937 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2940 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2945 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2947 -> Lrc<Vec<DefId>> {
2948 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2949 let item = tcx.hir.expect_item(id);
2950 let vec: Vec<_> = match item.node {
2951 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2952 trait_item_refs.iter()
2953 .map(|trait_item_ref| trait_item_ref.id)
2954 .map(|id| tcx.hir.local_def_id(id.node_id))
2957 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2958 impl_item_refs.iter()
2959 .map(|impl_item_ref| impl_item_ref.id)
2960 .map(|id| tcx.hir.local_def_id(id.node_id))
2963 hir::ItemKind::TraitAlias(..) => vec![],
2964 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2969 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2970 tcx.hir.span_if_local(def_id).unwrap()
2973 /// If the given def ID describes an item belonging to a trait,
2974 /// return the ID of the trait that the trait item belongs to.
2975 /// Otherwise, return `None`.
2976 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2977 tcx.opt_associated_item(def_id)
2978 .and_then(|associated_item| {
2979 match associated_item.container {
2980 TraitContainer(def_id) => Some(def_id),
2981 ImplContainer(_) => None
2986 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
2987 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
2988 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2989 if let Node::Item(item) = tcx.hir.get(node_id) {
2990 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
2991 return exist_ty.impl_trait_fn;
2998 /// Returns `true` if `def_id` is a trait alias.
2999 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3000 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3001 if let Node::Item(item) = tcx.hir.get(node_id) {
3002 if let hir::ItemKind::TraitAlias(..) = item.node {
3010 /// See `ParamEnv` struct definition for details.
3011 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3015 // The param_env of an impl Trait type is its defining function's param_env
3016 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3017 return param_env(tcx, parent);
3019 // Compute the bounds on Self and the type parameters.
3021 let InstantiatedPredicates { predicates } =
3022 tcx.predicates_of(def_id).instantiate_identity(tcx);
3024 // Finally, we have to normalize the bounds in the environment, in
3025 // case they contain any associated type projections. This process
3026 // can yield errors if the put in illegal associated types, like
3027 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3028 // report these errors right here; this doesn't actually feel
3029 // right to me, because constructing the environment feels like a
3030 // kind of a "idempotent" action, but I'm not sure where would be
3031 // a better place. In practice, we construct environments for
3032 // every fn once during type checking, and we'll abort if there
3033 // are any errors at that point, so after type checking you can be
3034 // sure that this will succeed without errors anyway.
3036 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3037 traits::Reveal::UserFacing);
3039 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3040 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3042 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3043 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3046 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3047 crate_num: CrateNum) -> CrateDisambiguator {
3048 assert_eq!(crate_num, LOCAL_CRATE);
3049 tcx.sess.local_crate_disambiguator()
3052 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3053 crate_num: CrateNum) -> Symbol {
3054 assert_eq!(crate_num, LOCAL_CRATE);
3055 tcx.crate_name.clone()
3058 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3059 crate_num: CrateNum)
3061 assert_eq!(crate_num, LOCAL_CRATE);
3065 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3066 instance_def: InstanceDef<'tcx>)
3068 match instance_def {
3069 InstanceDef::Item(..) |
3070 InstanceDef::DropGlue(..) => {
3071 let mir = tcx.instance_mir(instance_def);
3072 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3074 // Estimate the size of other compiler-generated shims to be 1.
3079 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3080 context::provide(providers);
3081 erase_regions::provide(providers);
3082 layout::provide(providers);
3083 util::provide(providers);
3084 constness::provide(providers);
3085 *providers = ty::query::Providers {
3087 associated_item_def_ids,
3088 adt_sized_constraint,
3092 crate_disambiguator,
3093 original_crate_name,
3095 trait_impls_of: trait_def::trait_impls_of_provider,
3096 instance_def_size_estimate,
3101 /// A map for the local crate mapping each type to a vector of its
3102 /// inherent impls. This is not meant to be used outside of coherence;
3103 /// rather, you should request the vector for a specific type via
3104 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3105 /// (constructing this map requires touching the entire crate).
3106 #[derive(Clone, Debug)]
3107 pub struct CrateInherentImpls {
3108 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3111 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3112 pub struct SymbolName {
3113 // FIXME: we don't rely on interning or equality here - better have
3114 // this be a `&'tcx str`.
3115 pub name: InternedString
3118 impl_stable_hash_for!(struct self::SymbolName {
3123 pub fn new(name: &str) -> SymbolName {
3125 name: Symbol::intern(name).as_interned_str()
3129 pub fn as_str(&self) -> LocalInternedString {
3134 impl fmt::Display for SymbolName {
3135 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3136 fmt::Display::fmt(&self.name, fmt)
3140 impl fmt::Debug for SymbolName {
3141 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3142 fmt::Display::fmt(&self.name, fmt)