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::layout::VariantIdx;
36 use ty::subst::{Subst, Substs};
37 use ty::util::{IntTypeExt, Discr};
38 use ty::walk::TypeWalker;
39 use util::captures::Captures;
40 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
41 use arena::SyncDroplessArena;
42 use session::DataTypeKind;
44 use serialize::{self, Encodable, Encoder};
45 use std::cell::RefCell;
46 use std::cmp::{self, Ordering};
48 use std::hash::{Hash, Hasher};
50 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
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, IndexVec};
61 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
66 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
67 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
68 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
69 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
70 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
71 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
72 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
73 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
74 pub use self::sty::RegionKind;
75 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
76 pub use self::sty::BoundRegion::*;
77 pub use self::sty::InferTy::*;
78 pub use self::sty::RegionKind::*;
79 pub use self::sty::TyKind::*;
81 pub use self::binding::BindingMode;
82 pub use self::binding::BindingMode::*;
84 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
85 pub use self::context::{Lift, TypeckTables};
87 pub use self::instance::{Instance, InstanceDef};
89 pub use self::trait_def::TraitDef;
91 pub use self::query::queries;
103 pub mod inhabitedness;
120 mod structural_impls;
125 /// The complete set of all analyses described in this module. This is
126 /// produced by the driver and fed to codegen and later passes.
128 /// NB: These contents are being migrated into queries using the
129 /// *on-demand* infrastructure.
131 pub struct CrateAnalysis {
132 pub access_levels: Lrc<AccessLevels>,
134 pub glob_map: Option<hir::GlobMap>,
138 pub struct Resolutions {
139 pub freevars: FreevarMap,
140 pub trait_map: TraitMap,
141 pub maybe_unused_trait_imports: NodeSet,
142 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
143 pub export_map: ExportMap,
144 /// Extern prelude entries. The value is `true` if the entry was introduced
145 /// via `extern crate` item and not `--extern` option or compiler built-in.
146 pub extern_prelude: FxHashMap<Name, bool>,
149 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
150 pub enum AssociatedItemContainer {
151 TraitContainer(DefId),
152 ImplContainer(DefId),
155 impl AssociatedItemContainer {
156 /// Asserts that this is the def-id of an associated item declared
157 /// in a trait, and returns the trait def-id.
158 pub fn assert_trait(&self) -> DefId {
160 TraitContainer(id) => id,
161 _ => bug!("associated item has wrong container type: {:?}", self)
165 pub fn id(&self) -> DefId {
167 TraitContainer(id) => id,
168 ImplContainer(id) => id,
173 /// The "header" of an impl is everything outside the body: a Self type, a trait
174 /// ref (in the case of a trait impl), and a set of predicates (from the
175 /// bounds/where clauses).
176 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
177 pub struct ImplHeader<'tcx> {
178 pub impl_def_id: DefId,
179 pub self_ty: Ty<'tcx>,
180 pub trait_ref: Option<TraitRef<'tcx>>,
181 pub predicates: Vec<Predicate<'tcx>>,
184 #[derive(Copy, Clone, Debug, PartialEq)]
185 pub struct AssociatedItem {
188 pub kind: AssociatedKind,
190 pub defaultness: hir::Defaultness,
191 pub container: AssociatedItemContainer,
193 /// Whether this is a method with an explicit self
194 /// as its first argument, allowing method calls.
195 pub method_has_self_argument: bool,
198 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
199 pub enum AssociatedKind {
206 impl AssociatedItem {
207 pub fn def(&self) -> Def {
209 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
210 AssociatedKind::Method => Def::Method(self.def_id),
211 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
212 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
216 /// Tests whether the associated item admits a non-trivial implementation
218 pub fn relevant_for_never<'tcx>(&self) -> bool {
220 AssociatedKind::Existential |
221 AssociatedKind::Const |
222 AssociatedKind::Type => true,
223 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
224 AssociatedKind::Method => !self.method_has_self_argument,
228 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
230 ty::AssociatedKind::Method => {
231 // We skip the binder here because the binder would deanonymize all
232 // late-bound regions, and we don't want method signatures to show up
233 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
234 // regions just fine, showing `fn(&MyType)`.
235 tcx.fn_sig(self.def_id).skip_binder().to_string()
237 ty::AssociatedKind::Type => format!("type {};", self.ident),
238 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
239 ty::AssociatedKind::Const => {
240 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
246 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
247 pub enum Visibility {
248 /// Visible everywhere (including in other crates).
250 /// Visible only in the given crate-local module.
252 /// Not visible anywhere in the local crate. This is the visibility of private external items.
256 pub trait DefIdTree: Copy {
257 fn parent(self, id: DefId) -> Option<DefId>;
259 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
260 if descendant.krate != ancestor.krate {
264 while descendant != ancestor {
265 match self.parent(descendant) {
266 Some(parent) => descendant = parent,
267 None => return false,
274 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
275 fn parent(self, id: DefId) -> Option<DefId> {
276 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
281 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt<'_, '_, '_>) -> Self {
282 match visibility.node {
283 hir::VisibilityKind::Public => Visibility::Public,
284 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
285 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
286 // If there is no resolution, `resolve` will have already reported an error, so
287 // assume that the visibility is public to avoid reporting more privacy errors.
288 Def::Err => Visibility::Public,
289 def => Visibility::Restricted(def.def_id()),
291 hir::VisibilityKind::Inherited => {
292 Visibility::Restricted(tcx.hir.get_module_parent(id))
297 /// Returns `true` if an item with this visibility is accessible from the given block.
298 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
299 let restriction = match self {
300 // Public items are visible everywhere.
301 Visibility::Public => return true,
302 // Private items from other crates are visible nowhere.
303 Visibility::Invisible => return false,
304 // Restricted items are visible in an arbitrary local module.
305 Visibility::Restricted(other) if other.krate != module.krate => return false,
306 Visibility::Restricted(module) => module,
309 tree.is_descendant_of(module, restriction)
312 /// Returns `true` if this visibility is at least as accessible as the given visibility
313 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
314 let vis_restriction = match vis {
315 Visibility::Public => return self == Visibility::Public,
316 Visibility::Invisible => return true,
317 Visibility::Restricted(module) => module,
320 self.is_accessible_from(vis_restriction, tree)
323 // Returns `true` if this item is visible anywhere in the local crate.
324 pub fn is_visible_locally(self) -> bool {
326 Visibility::Public => true,
327 Visibility::Restricted(def_id) => def_id.is_local(),
328 Visibility::Invisible => false,
333 #[derive(Copy, Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Hash)]
335 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
336 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
337 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
338 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
341 /// The crate variances map is computed during typeck and contains the
342 /// variance of every item in the local crate. You should not use it
343 /// directly, because to do so will make your pass dependent on the
344 /// HIR of every item in the local crate. Instead, use
345 /// `tcx.variances_of()` to get the variance for a *particular*
347 pub struct CrateVariancesMap {
348 /// For each item with generics, maps to a vector of the variance
349 /// of its generics. If an item has no generics, it will have no
351 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
353 /// An empty vector, useful for cloning.
354 pub empty_variance: Lrc<Vec<ty::Variance>>,
358 /// `a.xform(b)` combines the variance of a context with the
359 /// variance of a type with the following meaning. If we are in a
360 /// context with variance `a`, and we encounter a type argument in
361 /// a position with variance `b`, then `a.xform(b)` is the new
362 /// variance with which the argument appears.
368 /// Here, the "ambient" variance starts as covariant. `*mut T` is
369 /// invariant with respect to `T`, so the variance in which the
370 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
371 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
372 /// respect to its type argument `T`, and hence the variance of
373 /// the `i32` here is `Invariant.xform(Covariant)`, which results
374 /// (again) in `Invariant`.
378 /// fn(*const Vec<i32>, *mut Vec<i32)
380 /// The ambient variance is covariant. A `fn` type is
381 /// contravariant with respect to its parameters, so the variance
382 /// within which both pointer types appear is
383 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
384 /// T` is covariant with respect to `T`, so the variance within
385 /// which the first `Vec<i32>` appears is
386 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
387 /// is true for its `i32` argument. In the `*mut T` case, the
388 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
389 /// and hence the outermost type is `Invariant` with respect to
390 /// `Vec<i32>` (and its `i32` argument).
392 /// Source: Figure 1 of "Taming the Wildcards:
393 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
394 pub fn xform(self, v: ty::Variance) -> ty::Variance {
396 // Figure 1, column 1.
397 (ty::Covariant, ty::Covariant) => ty::Covariant,
398 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
399 (ty::Covariant, ty::Invariant) => ty::Invariant,
400 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
402 // Figure 1, column 2.
403 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
404 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
405 (ty::Contravariant, ty::Invariant) => ty::Invariant,
406 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
408 // Figure 1, column 3.
409 (ty::Invariant, _) => ty::Invariant,
411 // Figure 1, column 4.
412 (ty::Bivariant, _) => ty::Bivariant,
417 // Contains information needed to resolve types and (in the future) look up
418 // the types of AST nodes.
419 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
420 pub struct CReaderCacheKey {
425 // Flags that we track on types. These flags are propagated upwards
426 // through the type during type construction, so that we can quickly
427 // check whether the type has various kinds of types in it without
428 // recursing over the type itself.
430 pub struct TypeFlags: u32 {
431 const HAS_PARAMS = 1 << 0;
432 const HAS_SELF = 1 << 1;
433 const HAS_TY_INFER = 1 << 2;
434 const HAS_RE_INFER = 1 << 3;
435 const HAS_RE_SKOL = 1 << 4;
437 /// Does this have any `ReEarlyBound` regions? Used to
438 /// determine whether substitition is required, since those
439 /// represent regions that are bound in a `ty::Generics` and
440 /// hence may be substituted.
441 const HAS_RE_EARLY_BOUND = 1 << 5;
443 /// Does this have any region that "appears free" in the type?
444 /// Basically anything but `ReLateBound` and `ReErased`.
445 const HAS_FREE_REGIONS = 1 << 6;
447 /// Is an error type reachable?
448 const HAS_TY_ERR = 1 << 7;
449 const HAS_PROJECTION = 1 << 8;
451 // FIXME: Rename this to the actual property since it's used for generators too
452 const HAS_TY_CLOSURE = 1 << 9;
454 // `true` if there are "names" of types and regions and so forth
455 // that are local to a particular fn
456 const HAS_FREE_LOCAL_NAMES = 1 << 10;
458 // Present if the type belongs in a local type context.
459 // Only set for Infer other than Fresh.
460 const KEEP_IN_LOCAL_TCX = 1 << 11;
462 // Is there a projection that does not involve a bound region?
463 // Currently we can't normalize projections w/ bound regions.
464 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
466 /// Does this have any `ReLateBound` regions? Used to check
467 /// if a global bound is safe to evaluate.
468 const HAS_RE_LATE_BOUND = 1 << 13;
470 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
471 TypeFlags::HAS_SELF.bits |
472 TypeFlags::HAS_RE_EARLY_BOUND.bits;
474 // Flags representing the nominal content of a type,
475 // computed by FlagsComputation. If you add a new nominal
476 // flag, it should be added here too.
477 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
478 TypeFlags::HAS_SELF.bits |
479 TypeFlags::HAS_TY_INFER.bits |
480 TypeFlags::HAS_RE_INFER.bits |
481 TypeFlags::HAS_RE_SKOL.bits |
482 TypeFlags::HAS_RE_EARLY_BOUND.bits |
483 TypeFlags::HAS_FREE_REGIONS.bits |
484 TypeFlags::HAS_TY_ERR.bits |
485 TypeFlags::HAS_PROJECTION.bits |
486 TypeFlags::HAS_TY_CLOSURE.bits |
487 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
488 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
489 TypeFlags::HAS_RE_LATE_BOUND.bits;
493 pub struct TyS<'tcx> {
494 pub sty: TyKind<'tcx>,
495 pub flags: TypeFlags,
497 /// This is a kind of confusing thing: it stores the smallest
500 /// (a) the binder itself captures nothing but
501 /// (b) all the late-bound things within the type are captured
502 /// by some sub-binder.
504 /// So, for a type without any late-bound things, like `u32`, this
505 /// will be INNERMOST, because that is the innermost binder that
506 /// captures nothing. But for a type `&'D u32`, where `'D` is a
507 /// late-bound region with debruijn index D, this would be D+1 --
508 /// the binder itself does not capture D, but D is captured by an
511 /// We call this concept an "exclusive" binder D (because all
512 /// debruijn indices within the type are contained within `0..D`
514 outer_exclusive_binder: ty::DebruijnIndex,
517 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
518 #[cfg(target_arch = "x86_64")]
519 static_assert!(MEM_SIZE_OF_TY_S: ::std::mem::size_of::<TyS<'_>>() == 32);
521 impl<'tcx> Ord for TyS<'tcx> {
522 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
523 self.sty.cmp(&other.sty)
527 impl<'tcx> PartialOrd for TyS<'tcx> {
528 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
529 Some(self.sty.cmp(&other.sty))
533 impl<'tcx> PartialEq for TyS<'tcx> {
535 fn eq(&self, other: &TyS<'tcx>) -> bool {
539 impl<'tcx> Eq for TyS<'tcx> {}
541 impl<'tcx> Hash for TyS<'tcx> {
542 fn hash<H: Hasher>(&self, s: &mut H) {
543 (self as *const TyS<'_>).hash(s)
547 impl<'tcx> TyS<'tcx> {
548 pub fn is_primitive_ty(&self) -> bool {
555 TyKind::Infer(InferTy::IntVar(_)) |
556 TyKind::Infer(InferTy::FloatVar(_)) |
557 TyKind::Infer(InferTy::FreshIntTy(_)) |
558 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
559 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
564 pub fn is_suggestable(&self) -> bool {
569 TyKind::Dynamic(..) |
570 TyKind::Closure(..) |
572 TyKind::Projection(..) => false,
578 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
579 fn hash_stable<W: StableHasherResult>(&self,
580 hcx: &mut StableHashingContext<'a>,
581 hasher: &mut StableHasher<W>) {
585 // The other fields just provide fast access to information that is
586 // also contained in `sty`, so no need to hash them.
589 outer_exclusive_binder: _,
592 sty.hash_stable(hcx, hasher);
596 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
598 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
599 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
601 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
604 /// A dummy type used to force List to by unsized without requiring fat pointers
605 type OpaqueListContents;
608 /// A wrapper for slices with the additional invariant
609 /// that the slice is interned and no other slice with
610 /// the same contents can exist in the same context.
611 /// This means we can use pointer for both
612 /// equality comparisons and hashing.
613 /// Note: `Slice` was already taken by the `Ty`.
618 opaque: OpaqueListContents,
621 unsafe impl<T: Sync> Sync for List<T> {}
623 impl<T: Copy> List<T> {
625 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
626 assert!(!mem::needs_drop::<T>());
627 assert!(mem::size_of::<T>() != 0);
628 assert!(slice.len() != 0);
630 // Align up the size of the len (usize) field
631 let align = mem::align_of::<T>();
632 let align_mask = align - 1;
633 let offset = mem::size_of::<usize>();
634 let offset = (offset + align_mask) & !align_mask;
636 let size = offset + slice.len() * mem::size_of::<T>();
638 let mem = arena.alloc_raw(
640 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
642 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
644 result.len = slice.len();
646 // Write the elements
647 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
648 arena_slice.copy_from_slice(slice);
655 impl<T: fmt::Debug> fmt::Debug for List<T> {
656 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
661 impl<T: Encodable> Encodable for List<T> {
663 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
668 impl<T> Ord for List<T> where T: Ord {
669 fn cmp(&self, other: &List<T>) -> Ordering {
670 if self == other { Ordering::Equal } else {
671 <[T] as Ord>::cmp(&**self, &**other)
676 impl<T> PartialOrd for List<T> where T: PartialOrd {
677 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
678 if self == other { Some(Ordering::Equal) } else {
679 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
684 impl<T: PartialEq> PartialEq for List<T> {
686 fn eq(&self, other: &List<T>) -> bool {
690 impl<T: Eq> Eq for List<T> {}
692 impl<T> Hash for List<T> {
694 fn hash<H: Hasher>(&self, s: &mut H) {
695 (self as *const List<T>).hash(s)
699 impl<T> Deref for List<T> {
702 fn deref(&self) -> &[T] {
704 slice::from_raw_parts(self.data.as_ptr(), self.len)
709 impl<'a, T> IntoIterator for &'a List<T> {
711 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
713 fn into_iter(self) -> Self::IntoIter {
718 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
722 pub fn empty<'a>() -> &'a List<T> {
723 #[repr(align(64), C)]
724 struct EmptySlice([u8; 64]);
725 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
726 assert!(mem::align_of::<T>() <= 64);
728 &*(&EMPTY_SLICE as *const _ as *const List<T>)
733 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
734 pub struct UpvarPath {
735 pub hir_id: hir::HirId,
738 /// Upvars do not get their own node-id. Instead, we use the pair of
739 /// the original var id (that is, the root variable that is referenced
740 /// by the upvar) and the id of the closure expression.
741 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
743 pub var_path: UpvarPath,
744 pub closure_expr_id: LocalDefId,
747 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
748 pub enum BorrowKind {
749 /// Data must be immutable and is aliasable.
752 /// Data must be immutable but not aliasable. This kind of borrow
753 /// cannot currently be expressed by the user and is used only in
754 /// implicit closure bindings. It is needed when the closure
755 /// is borrowing or mutating a mutable referent, e.g.:
757 /// let x: &mut isize = ...;
758 /// let y = || *x += 5;
760 /// If we were to try to translate this closure into a more explicit
761 /// form, we'd encounter an error with the code as written:
763 /// struct Env { x: & &mut isize }
764 /// let x: &mut isize = ...;
765 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
766 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
768 /// This is then illegal because you cannot mutate a `&mut` found
769 /// in an aliasable location. To solve, you'd have to translate with
770 /// an `&mut` borrow:
772 /// struct Env { x: & &mut isize }
773 /// let x: &mut isize = ...;
774 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
775 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
777 /// Now the assignment to `**env.x` is legal, but creating a
778 /// mutable pointer to `x` is not because `x` is not mutable. We
779 /// could fix this by declaring `x` as `let mut x`. This is ok in
780 /// user code, if awkward, but extra weird for closures, since the
781 /// borrow is hidden.
783 /// So we introduce a "unique imm" borrow -- the referent is
784 /// immutable, but not aliasable. This solves the problem. For
785 /// simplicity, we don't give users the way to express this
786 /// borrow, it's just used when translating closures.
789 /// Data is mutable and not aliasable.
793 /// Information describing the capture of an upvar. This is computed
794 /// during `typeck`, specifically by `regionck`.
795 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
796 pub enum UpvarCapture<'tcx> {
797 /// Upvar is captured by value. This is always true when the
798 /// closure is labeled `move`, but can also be true in other cases
799 /// depending on inference.
802 /// Upvar is captured by reference.
803 ByRef(UpvarBorrow<'tcx>),
806 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
807 pub struct UpvarBorrow<'tcx> {
808 /// The kind of borrow: by-ref upvars have access to shared
809 /// immutable borrows, which are not part of the normal language
811 pub kind: BorrowKind,
813 /// Region of the resulting reference.
814 pub region: ty::Region<'tcx>,
817 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
819 #[derive(Copy, Clone)]
820 pub struct ClosureUpvar<'tcx> {
826 #[derive(Clone, Copy, PartialEq, Eq)]
827 pub enum IntVarValue {
829 UintType(ast::UintTy),
832 #[derive(Clone, Copy, PartialEq, Eq)]
833 pub struct FloatVarValue(pub ast::FloatTy);
835 impl ty::EarlyBoundRegion {
836 pub fn to_bound_region(&self) -> ty::BoundRegion {
837 ty::BoundRegion::BrNamed(self.def_id, self.name)
840 /// Does this early bound region have a name? Early bound regions normally
841 /// always have names except when using anonymous lifetimes (`'_`).
842 pub fn has_name(&self) -> bool {
843 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
847 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
848 pub enum GenericParamDefKind {
852 object_lifetime_default: ObjectLifetimeDefault,
853 synthetic: Option<hir::SyntheticTyParamKind>,
857 #[derive(Clone, RustcEncodable, RustcDecodable)]
858 pub struct GenericParamDef {
859 pub name: InternedString,
863 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
864 /// on generic parameter `'a`/`T`, asserts data behind the parameter
865 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
866 pub pure_wrt_drop: bool,
868 pub kind: GenericParamDefKind,
871 impl GenericParamDef {
872 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
873 if let GenericParamDefKind::Lifetime = self.kind {
874 ty::EarlyBoundRegion {
880 bug!("cannot convert a non-lifetime parameter def to an early bound region")
884 pub fn to_bound_region(&self) -> ty::BoundRegion {
885 if let GenericParamDefKind::Lifetime = self.kind {
886 self.to_early_bound_region_data().to_bound_region()
888 bug!("cannot convert a non-lifetime parameter def to an early bound region")
894 pub struct GenericParamCount {
895 pub lifetimes: usize,
899 /// Information about the formal type/lifetime parameters associated
900 /// with an item or method. Analogous to hir::Generics.
902 /// The ordering of parameters is the same as in Subst (excluding child generics):
903 /// Self (optionally), Lifetime params..., Type params...
904 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
905 pub struct Generics {
906 pub parent: Option<DefId>,
907 pub parent_count: usize,
908 pub params: Vec<GenericParamDef>,
910 /// Reverse map to the `index` field of each `GenericParamDef`
911 pub param_def_id_to_index: FxHashMap<DefId, u32>,
914 pub has_late_bound_regions: Option<Span>,
917 impl<'a, 'gcx, 'tcx> Generics {
918 pub fn count(&self) -> usize {
919 self.parent_count + self.params.len()
922 pub fn own_counts(&self) -> GenericParamCount {
923 // We could cache this as a property of `GenericParamCount`, but
924 // the aim is to refactor this away entirely eventually and the
925 // presence of this method will be a constant reminder.
926 let mut own_counts: GenericParamCount = Default::default();
928 for param in &self.params {
930 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
931 GenericParamDefKind::Type { .. } => own_counts.types += 1,
938 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
939 for param in &self.params {
941 GenericParamDefKind::Type { .. } => return true,
942 GenericParamDefKind::Lifetime => {}
945 if let Some(parent_def_id) = self.parent {
946 let parent = tcx.generics_of(parent_def_id);
947 parent.requires_monomorphization(tcx)
953 pub fn region_param(&'tcx self,
954 param: &EarlyBoundRegion,
955 tcx: TyCtxt<'a, 'gcx, 'tcx>)
956 -> &'tcx GenericParamDef
958 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
959 let param = &self.params[index as usize];
961 ty::GenericParamDefKind::Lifetime => param,
962 _ => bug!("expected lifetime parameter, but found another generic parameter")
965 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
966 .region_param(param, tcx)
970 /// Returns the `GenericParamDef` associated with this `ParamTy`.
971 pub fn type_param(&'tcx self,
973 tcx: TyCtxt<'a, 'gcx, 'tcx>)
974 -> &'tcx GenericParamDef {
975 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
976 let param = &self.params[index as usize];
978 ty::GenericParamDefKind::Type {..} => param,
979 _ => bug!("expected type parameter, but found another generic parameter")
982 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
983 .type_param(param, tcx)
988 /// Bounds on generics.
989 #[derive(Clone, Default)]
990 pub struct GenericPredicates<'tcx> {
991 pub parent: Option<DefId>,
992 pub predicates: Vec<(Predicate<'tcx>, Span)>,
995 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
996 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
998 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
999 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1000 -> InstantiatedPredicates<'tcx> {
1001 let mut instantiated = InstantiatedPredicates::empty();
1002 self.instantiate_into(tcx, &mut instantiated, substs);
1006 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
1007 -> InstantiatedPredicates<'tcx> {
1008 InstantiatedPredicates {
1009 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
1013 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1014 instantiated: &mut InstantiatedPredicates<'tcx>,
1015 substs: &Substs<'tcx>) {
1016 if let Some(def_id) = self.parent {
1017 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1019 instantiated.predicates.extend(
1020 self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)),
1024 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1025 -> InstantiatedPredicates<'tcx> {
1026 let mut instantiated = InstantiatedPredicates::empty();
1027 self.instantiate_identity_into(tcx, &mut instantiated);
1031 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1032 instantiated: &mut InstantiatedPredicates<'tcx>) {
1033 if let Some(def_id) = self.parent {
1034 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1036 instantiated.predicates.extend(self.predicates.iter().map(|&(p, _)| p))
1039 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1040 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1041 -> InstantiatedPredicates<'tcx>
1043 assert_eq!(self.parent, None);
1044 InstantiatedPredicates {
1045 predicates: self.predicates.iter().map(|(pred, _)| {
1046 pred.subst_supertrait(tcx, poly_trait_ref)
1052 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1053 pub enum Predicate<'tcx> {
1054 /// Corresponds to `where Foo: Bar<A,B,C>`. `Foo` here would be
1055 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1056 /// would be the type parameters.
1057 Trait(PolyTraitPredicate<'tcx>),
1060 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1063 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1065 /// where `<T as TraitRef>::Name == X`, approximately.
1066 /// See the `ProjectionPredicate` struct for details.
1067 Projection(PolyProjectionPredicate<'tcx>),
1069 /// no syntax: `T` well-formed
1070 WellFormed(Ty<'tcx>),
1072 /// trait must be object-safe
1075 /// No direct syntax. May be thought of as `where T: FnFoo<...>`
1076 /// for some substitutions `...` and `T` being a closure type.
1077 /// Satisfied (or refuted) once we know the closure's kind.
1078 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1081 Subtype(PolySubtypePredicate<'tcx>),
1083 /// Constant initializer must evaluate successfully.
1084 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1087 /// The crate outlives map is computed during typeck and contains the
1088 /// outlives of every item in the local crate. You should not use it
1089 /// directly, because to do so will make your pass dependent on the
1090 /// HIR of every item in the local crate. Instead, use
1091 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1093 pub struct CratePredicatesMap<'tcx> {
1094 /// For each struct with outlive bounds, maps to a vector of the
1095 /// predicate of its outlive bounds. If an item has no outlives
1096 /// bounds, it will have no entry.
1097 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1099 /// An empty vector, useful for cloning.
1100 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1103 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1104 fn as_ref(&self) -> &Predicate<'tcx> {
1109 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1110 /// Performs a substitution suitable for going from a
1111 /// poly-trait-ref to supertraits that must hold if that
1112 /// poly-trait-ref holds. This is slightly different from a normal
1113 /// substitution in terms of what happens with bound regions. See
1114 /// lengthy comment below for details.
1115 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1116 trait_ref: &ty::PolyTraitRef<'tcx>)
1117 -> ty::Predicate<'tcx>
1119 // The interaction between HRTB and supertraits is not entirely
1120 // obvious. Let me walk you (and myself) through an example.
1122 // Let's start with an easy case. Consider two traits:
1124 // trait Foo<'a>: Bar<'a,'a> { }
1125 // trait Bar<'b,'c> { }
1127 // Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
1128 // we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
1129 // knew that `Foo<'x>` (for any 'x) then we also know that
1130 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1131 // normal substitution.
1133 // In terms of why this is sound, the idea is that whenever there
1134 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1135 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1136 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1139 // Another example to be careful of is this:
1141 // trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
1142 // trait Bar1<'b,'c> { }
1144 // Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
1145 // The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
1146 // reason is similar to the previous example: any impl of
1147 // `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
1148 // basically we would want to collapse the bound lifetimes from
1149 // the input (`trait_ref`) and the supertraits.
1151 // To achieve this in practice is fairly straightforward. Let's
1152 // consider the more complicated scenario:
1154 // - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
1155 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
1156 // where both `'x` and `'b` would have a DB index of 1.
1157 // The substitution from the input trait-ref is therefore going to be
1158 // `'a => 'x` (where `'x` has a DB index of 1).
1159 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1160 // early-bound parameter and `'b' is a late-bound parameter with a
1162 // - If we replace `'a` with `'x` from the input, it too will have
1163 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1164 // just as we wanted.
1166 // There is only one catch. If we just apply the substitution `'a
1167 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1168 // adjust the DB index because we substituting into a binder (it
1169 // tries to be so smart...) resulting in `for<'x> for<'b>
1170 // Bar1<'x,'b>` (we have no syntax for this, so use your
1171 // imagination). Basically the 'x will have DB index of 2 and 'b
1172 // will have DB index of 1. Not quite what we want. So we apply
1173 // the substitution to the *contents* of the trait reference,
1174 // rather than the trait reference itself (put another way, the
1175 // substitution code expects equal binding levels in the values
1176 // from the substitution and the value being substituted into, and
1177 // this trick achieves that).
1179 let substs = &trait_ref.skip_binder().substs;
1181 Predicate::Trait(ref binder) =>
1182 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1183 Predicate::Subtype(ref binder) =>
1184 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1185 Predicate::RegionOutlives(ref binder) =>
1186 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1187 Predicate::TypeOutlives(ref binder) =>
1188 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1189 Predicate::Projection(ref binder) =>
1190 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1191 Predicate::WellFormed(data) =>
1192 Predicate::WellFormed(data.subst(tcx, substs)),
1193 Predicate::ObjectSafe(trait_def_id) =>
1194 Predicate::ObjectSafe(trait_def_id),
1195 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1196 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1197 Predicate::ConstEvaluatable(def_id, const_substs) =>
1198 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1203 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1204 pub struct TraitPredicate<'tcx> {
1205 pub trait_ref: TraitRef<'tcx>
1208 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1210 impl<'tcx> TraitPredicate<'tcx> {
1211 pub fn def_id(&self) -> DefId {
1212 self.trait_ref.def_id
1215 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1216 self.trait_ref.input_types()
1219 pub fn self_ty(&self) -> Ty<'tcx> {
1220 self.trait_ref.self_ty()
1224 impl<'tcx> PolyTraitPredicate<'tcx> {
1225 pub fn def_id(&self) -> DefId {
1226 // ok to skip binder since trait def-id does not care about regions
1227 self.skip_binder().def_id()
1231 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1232 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A: B`
1233 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1234 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1236 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1238 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1239 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1241 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1242 pub struct SubtypePredicate<'tcx> {
1243 pub a_is_expected: bool,
1247 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1249 /// This kind of predicate has no *direct* correspondent in the
1250 /// syntax, but it roughly corresponds to the syntactic forms:
1252 /// 1. `T: TraitRef<..., Item=Type>`
1253 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1255 /// In particular, form #1 is "desugared" to the combination of a
1256 /// normal trait predicate (`T: TraitRef<...>`) and one of these
1257 /// predicates. Form #2 is a broader form in that it also permits
1258 /// equality between arbitrary types. Processing an instance of
1259 /// Form #2 eventually yields one of these `ProjectionPredicate`
1260 /// instances to normalize the LHS.
1261 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1262 pub struct ProjectionPredicate<'tcx> {
1263 pub projection_ty: ProjectionTy<'tcx>,
1267 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1269 impl<'tcx> PolyProjectionPredicate<'tcx> {
1270 /// Returns the `DefId` of the associated item being projected.
1271 pub fn item_def_id(&self) -> DefId {
1272 self.skip_binder().projection_ty.item_def_id
1275 pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'_, '_, '_>) -> PolyTraitRef<'tcx> {
1276 // Note: unlike with `TraitRef::to_poly_trait_ref()`,
1277 // `self.0.trait_ref` is permitted to have escaping regions.
1278 // This is because here `self` has a `Binder` and so does our
1279 // return value, so we are preserving the number of binding
1281 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1284 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1285 self.map_bound(|predicate| predicate.ty)
1288 /// The `DefId` of the `TraitItem` for the associated type.
1290 /// Note that this is not the `DefId` of the `TraitRef` containing this
1291 /// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
1292 pub fn projection_def_id(&self) -> DefId {
1293 // okay to skip binder since trait def-id does not care about regions
1294 self.skip_binder().projection_ty.item_def_id
1298 pub trait ToPolyTraitRef<'tcx> {
1299 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1302 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1303 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1304 ty::Binder::dummy(self.clone())
1308 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1309 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1310 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1314 pub trait ToPredicate<'tcx> {
1315 fn to_predicate(&self) -> Predicate<'tcx>;
1318 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1319 fn to_predicate(&self) -> Predicate<'tcx> {
1320 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1321 trait_ref: self.clone()
1326 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1327 fn to_predicate(&self) -> Predicate<'tcx> {
1328 ty::Predicate::Trait(self.to_poly_trait_predicate())
1332 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1333 fn to_predicate(&self) -> Predicate<'tcx> {
1334 Predicate::RegionOutlives(self.clone())
1338 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1339 fn to_predicate(&self) -> Predicate<'tcx> {
1340 Predicate::TypeOutlives(self.clone())
1344 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1345 fn to_predicate(&self) -> Predicate<'tcx> {
1346 Predicate::Projection(self.clone())
1350 // A custom iterator used by Predicate::walk_tys.
1351 enum WalkTysIter<'tcx, I, J, K>
1352 where I: Iterator<Item = Ty<'tcx>>,
1353 J: Iterator<Item = Ty<'tcx>>,
1354 K: Iterator<Item = Ty<'tcx>>
1358 Two(Ty<'tcx>, Ty<'tcx>),
1364 impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
1365 where I: Iterator<Item = Ty<'tcx>>,
1366 J: Iterator<Item = Ty<'tcx>>,
1367 K: Iterator<Item = Ty<'tcx>>
1369 type Item = Ty<'tcx>;
1371 fn next(&mut self) -> Option<Ty<'tcx>> {
1373 WalkTysIter::None => None,
1374 WalkTysIter::One(item) => {
1375 *self = WalkTysIter::None;
1378 WalkTysIter::Two(item1, item2) => {
1379 *self = WalkTysIter::One(item2);
1382 WalkTysIter::Types(ref mut iter) => {
1385 WalkTysIter::InputTypes(ref mut iter) => {
1388 WalkTysIter::ProjectionTypes(ref mut iter) => {
1395 impl<'tcx> Predicate<'tcx> {
1396 /// Iterates over the types in this predicate. Note that in all
1397 /// cases this is skipping over a binder, so late-bound regions
1398 /// with depth 0 are bound by the predicate.
1399 pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
1401 ty::Predicate::Trait(ref data) => {
1402 WalkTysIter::InputTypes(data.skip_binder().input_types())
1404 ty::Predicate::Subtype(binder) => {
1405 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1406 WalkTysIter::Two(a, b)
1408 ty::Predicate::TypeOutlives(binder) => {
1409 WalkTysIter::One(binder.skip_binder().0)
1411 ty::Predicate::RegionOutlives(..) => {
1414 ty::Predicate::Projection(ref data) => {
1415 let inner = data.skip_binder();
1416 WalkTysIter::ProjectionTypes(
1417 inner.projection_ty.substs.types().chain(Some(inner.ty)))
1419 ty::Predicate::WellFormed(data) => {
1420 WalkTysIter::One(data)
1422 ty::Predicate::ObjectSafe(_trait_def_id) => {
1425 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1426 WalkTysIter::Types(closure_substs.substs.types())
1428 ty::Predicate::ConstEvaluatable(_, substs) => {
1429 WalkTysIter::Types(substs.types())
1434 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1436 Predicate::Trait(ref t) => {
1437 Some(t.to_poly_trait_ref())
1439 Predicate::Projection(..) |
1440 Predicate::Subtype(..) |
1441 Predicate::RegionOutlives(..) |
1442 Predicate::WellFormed(..) |
1443 Predicate::ObjectSafe(..) |
1444 Predicate::ClosureKind(..) |
1445 Predicate::TypeOutlives(..) |
1446 Predicate::ConstEvaluatable(..) => {
1452 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1454 Predicate::TypeOutlives(data) => {
1457 Predicate::Trait(..) |
1458 Predicate::Projection(..) |
1459 Predicate::Subtype(..) |
1460 Predicate::RegionOutlives(..) |
1461 Predicate::WellFormed(..) |
1462 Predicate::ObjectSafe(..) |
1463 Predicate::ClosureKind(..) |
1464 Predicate::ConstEvaluatable(..) => {
1471 /// Represents the bounds declared on a particular set of type
1472 /// parameters. Should eventually be generalized into a flag list of
1473 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1474 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1475 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1476 /// the `GenericPredicates` are expressed in terms of the bound type
1477 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1478 /// represented a set of bounds for some particular instantiation,
1479 /// meaning that the generic parameters have been substituted with
1484 /// struct Foo<T,U:Bar<T>> { ... }
1486 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1487 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1488 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1489 /// [usize:Bar<isize>]]`.
1491 pub struct InstantiatedPredicates<'tcx> {
1492 pub predicates: Vec<Predicate<'tcx>>,
1495 impl<'tcx> InstantiatedPredicates<'tcx> {
1496 pub fn empty() -> InstantiatedPredicates<'tcx> {
1497 InstantiatedPredicates { predicates: vec![] }
1500 pub fn is_empty(&self) -> bool {
1501 self.predicates.is_empty()
1505 /// "Universes" are used during type- and trait-checking in the
1506 /// presence of `for<..>` binders to control what sets of names are
1507 /// visible. Universes are arranged into a tree: the root universe
1508 /// contains names that are always visible. Each child then adds a new
1509 /// set of names that are visible, in addition to those of its parent.
1510 /// We say that the child universe "extends" the parent universe with
1513 /// To make this more concrete, consider this program:
1517 /// fn bar<T>(x: T) {
1518 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1522 /// The struct name `Foo` is in the root universe U0. But the type
1523 /// parameter `T`, introduced on `bar`, is in an extended universe U1
1524 /// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
1525 /// of `bar`, we cannot name `T`. Then, within the type of `y`, the
1526 /// region `'a` is in a universe U2 that extends U1, because we can
1527 /// name it inside the fn type but not outside.
1529 /// Universes are used to do type- and trait-checking around these
1530 /// "forall" binders (also called **universal quantification**). The
1531 /// idea is that when, in the body of `bar`, we refer to `T` as a
1532 /// type, we aren't referring to any type in particular, but rather a
1533 /// kind of "fresh" type that is distinct from all other types we have
1534 /// actually declared. This is called a **placeholder** type, and we
1535 /// use universes to talk about this. In other words, a type name in
1536 /// universe 0 always corresponds to some "ground" type that the user
1537 /// declared, but a type name in a non-zero universe is a placeholder
1538 /// type -- an idealized representative of "types in general" that we
1539 /// use for checking generic functions.
1541 pub struct UniverseIndex {
1542 DEBUG_FORMAT = "U{}",
1546 impl_stable_hash_for!(struct UniverseIndex { private });
1548 impl UniverseIndex {
1549 pub const ROOT: UniverseIndex = UniverseIndex::from_u32_const(0);
1551 /// Returns the "next" universe index in order -- this new index
1552 /// is considered to extend all previous universes. This
1553 /// corresponds to entering a `forall` quantifier. So, for
1554 /// example, suppose we have this type in universe `U`:
1557 /// for<'a> fn(&'a u32)
1560 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1561 /// new universe that extends `U` -- in this new universe, we can
1562 /// name the region `'a`, but that region was not nameable from
1563 /// `U` because it was not in scope there.
1564 pub fn next_universe(self) -> UniverseIndex {
1565 UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
1568 /// Returns `true` if `self` can name a name from `other` -- in other words,
1569 /// if the set of names in `self` is a superset of those in
1570 /// `other` (`self >= other`).
1571 pub fn can_name(self, other: UniverseIndex) -> bool {
1572 self.private >= other.private
1575 /// Returns `true` if `self` cannot name some names from `other` -- in other
1576 /// words, if the set of names in `self` is a strict subset of
1577 /// those in `other` (`self < other`).
1578 pub fn cannot_name(self, other: UniverseIndex) -> bool {
1579 self.private < other.private
1583 /// The "placeholder index" fully defines a placeholder region.
1584 /// Placeholder regions are identified by both a **universe** as well
1585 /// as a "bound-region" within that universe. The `bound_region` is
1586 /// basically a name -- distinct bound regions within the same
1587 /// universe are just two regions with an unknown relationship to one
1589 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
1590 pub struct Placeholder<T> {
1591 pub universe: UniverseIndex,
1595 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
1596 where T: HashStable<StableHashingContext<'a>>
1598 fn hash_stable<W: StableHasherResult>(
1600 hcx: &mut StableHashingContext<'a>,
1601 hasher: &mut StableHasher<W>
1603 self.universe.hash_stable(hcx, hasher);
1604 self.name.hash_stable(hcx, hasher);
1608 pub type PlaceholderRegion = Placeholder<BoundRegion>;
1610 pub type PlaceholderType = Placeholder<BoundVar>;
1612 /// When type checking, we use the `ParamEnv` to track
1613 /// details about the set of where-clauses that are in scope at this
1614 /// particular point.
1615 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1616 pub struct ParamEnv<'tcx> {
1617 /// Obligations that the caller must satisfy. This is basically
1618 /// the set of bounds on the in-scope type parameters, translated
1619 /// into Obligations, and elaborated and normalized.
1620 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1622 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1623 /// want `Reveal::All` -- note that this is always paired with an
1624 /// empty environment. To get that, use `ParamEnv::reveal()`.
1625 pub reveal: traits::Reveal,
1628 impl<'tcx> ParamEnv<'tcx> {
1629 /// Construct a trait environment suitable for contexts where
1630 /// there are no where clauses in scope. Hidden types (like `impl
1631 /// Trait`) are left hidden, so this is suitable for ordinary
1633 pub fn empty() -> Self {
1634 Self::new(List::empty(), Reveal::UserFacing)
1637 /// Construct a trait environment with no where clauses in scope
1638 /// where the values of all `impl Trait` and other hidden types
1639 /// are revealed. This is suitable for monomorphized, post-typeck
1640 /// environments like codegen or doing optimizations.
1642 /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
1643 /// or invoke `param_env.with_reveal_all()`.
1644 pub fn reveal_all() -> Self {
1645 Self::new(List::empty(), Reveal::All)
1648 /// Construct a trait environment with the given set of predicates.
1649 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1652 ty::ParamEnv { caller_bounds, reveal }
1655 /// Returns a new parameter environment with the same clauses, but
1656 /// which "reveals" the true results of projections in all cases
1657 /// (even for associated types that are specializable). This is
1658 /// the desired behavior during codegen and certain other special
1659 /// contexts; normally though we want to use `Reveal::UserFacing`,
1660 /// which is the default.
1661 pub fn with_reveal_all(self) -> Self {
1662 ty::ParamEnv { reveal: Reveal::All, ..self }
1665 /// Returns this same environment but with no caller bounds.
1666 pub fn without_caller_bounds(self) -> Self {
1667 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1670 /// Creates a suitable environment in which to perform trait
1671 /// queries on the given value. When type-checking, this is simply
1672 /// the pair of the environment plus value. But when reveal is set to
1673 /// All, then if `value` does not reference any type parameters, we will
1674 /// pair it with the empty environment. This improves caching and is generally
1677 /// NB: We preserve the environment when type-checking because it
1678 /// is possible for the user to have wacky where-clauses like
1679 /// `where Box<u32>: Copy`, which are clearly never
1680 /// satisfiable. We generally want to behave as if they were true,
1681 /// although the surrounding function is never reachable.
1682 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1684 Reveal::UserFacing => {
1693 || value.needs_infer()
1694 || value.has_param_types()
1695 || value.has_self_ty()
1703 param_env: self.without_caller_bounds(),
1712 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1713 pub struct ParamEnvAnd<'tcx, T> {
1714 pub param_env: ParamEnv<'tcx>,
1718 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1719 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1720 (self.param_env, self.value)
1724 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1725 where T: HashStable<StableHashingContext<'a>>
1727 fn hash_stable<W: StableHasherResult>(&self,
1728 hcx: &mut StableHashingContext<'a>,
1729 hasher: &mut StableHasher<W>) {
1735 param_env.hash_stable(hcx, hasher);
1736 value.hash_stable(hcx, hasher);
1740 #[derive(Copy, Clone, Debug)]
1741 pub struct Destructor {
1742 /// The def-id of the destructor method
1747 pub struct AdtFlags: u32 {
1748 const NO_ADT_FLAGS = 0;
1749 const IS_ENUM = 1 << 0;
1750 const IS_PHANTOM_DATA = 1 << 1;
1751 const IS_FUNDAMENTAL = 1 << 2;
1752 const IS_UNION = 1 << 3;
1753 const IS_BOX = 1 << 4;
1754 /// Indicates whether the type is an `Arc`.
1755 const IS_ARC = 1 << 5;
1756 /// Indicates whether the type is an `Rc`.
1757 const IS_RC = 1 << 6;
1758 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1759 /// (i.e., this flag is never set unless this ADT is an enum).
1760 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 7;
1765 pub struct VariantFlags: u32 {
1766 const NO_VARIANT_FLAGS = 0;
1767 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1768 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1773 pub struct VariantDef {
1774 /// The variant's DefId. If this is a tuple-like struct,
1775 /// this is the DefId of the struct's ctor.
1777 pub name: Name, // struct's name if this is a struct
1778 pub discr: VariantDiscr,
1779 pub fields: Vec<FieldDef>,
1780 pub ctor_kind: CtorKind,
1781 flags: VariantFlags,
1784 impl<'a, 'gcx, 'tcx> VariantDef {
1785 /// Create a new `VariantDef`.
1787 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1788 /// and for everything else, it is the variant DefId.
1789 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1790 /// this is the struct DefId for structs, and the variant DefId for variants.
1792 /// Note that we *could* use the constructor DefId, because the constructor attributes
1793 /// redirect to the base attributes, but compiling a small crate requires
1794 /// loading the AdtDefs for all the structs in the universe (e.g. coherence for any
1795 /// built-in trait), and we do not want to load attributes twice.
1797 /// If someone speeds up attribute loading to not be a performance concern, they can
1798 /// remove this hack and use the constructor DefId everywhere.
1799 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1802 discr: VariantDiscr,
1803 fields: Vec<FieldDef>,
1805 ctor_kind: CtorKind,
1806 attribute_def_id: DefId)
1809 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr,
1810 fields, adt_kind, ctor_kind, attribute_def_id);
1811 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1812 if adt_kind == AdtKind::Struct && tcx.has_attr(attribute_def_id, "non_exhaustive") {
1813 debug!("found non-exhaustive field list for {:?}", did);
1814 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1827 pub fn is_field_list_non_exhaustive(&self) -> bool {
1828 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1832 impl_stable_hash_for!(struct VariantDef {
1841 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1842 pub enum VariantDiscr {
1843 /// Explicit value for this variant, i.e. `X = 123`.
1844 /// The `DefId` corresponds to the embedded constant.
1847 /// The previous variant's discriminant plus one.
1848 /// For efficiency reasons, the distance from the
1849 /// last `Explicit` discriminant is being stored,
1850 /// or `0` for the first variant, if it has none.
1855 pub struct FieldDef {
1858 pub vis: Visibility,
1861 /// The definition of an abstract data type - a struct or enum.
1863 /// These are all interned (by intern_adt_def) into the adt_defs
1867 pub variants: IndexVec<self::layout::VariantIdx, VariantDef>,
1869 pub repr: ReprOptions,
1872 impl PartialOrd for AdtDef {
1873 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1874 Some(self.cmp(&other))
1878 /// There should be only one AdtDef for each `did`, therefore
1879 /// it is fine to implement `Ord` only based on `did`.
1880 impl Ord for AdtDef {
1881 fn cmp(&self, other: &AdtDef) -> Ordering {
1882 self.did.cmp(&other.did)
1886 impl PartialEq for AdtDef {
1887 // AdtDef are always interned and this is part of TyS equality
1889 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1892 impl Eq for AdtDef {}
1894 impl Hash for AdtDef {
1896 fn hash<H: Hasher>(&self, s: &mut H) {
1897 (self as *const AdtDef).hash(s)
1901 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1902 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1907 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1910 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1911 fn hash_stable<W: StableHasherResult>(&self,
1912 hcx: &mut StableHashingContext<'a>,
1913 hasher: &mut StableHasher<W>) {
1915 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
1918 let hash: Fingerprint = CACHE.with(|cache| {
1919 let addr = self as *const AdtDef as usize;
1920 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1928 let mut hasher = StableHasher::new();
1929 did.hash_stable(hcx, &mut hasher);
1930 variants.hash_stable(hcx, &mut hasher);
1931 flags.hash_stable(hcx, &mut hasher);
1932 repr.hash_stable(hcx, &mut hasher);
1938 hash.hash_stable(hcx, hasher);
1942 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1943 pub enum AdtKind { Struct, Union, Enum }
1945 impl Into<DataTypeKind> for AdtKind {
1946 fn into(self) -> DataTypeKind {
1948 AdtKind::Struct => DataTypeKind::Struct,
1949 AdtKind::Union => DataTypeKind::Union,
1950 AdtKind::Enum => DataTypeKind::Enum,
1956 #[derive(RustcEncodable, RustcDecodable, Default)]
1957 pub struct ReprFlags: u8 {
1958 const IS_C = 1 << 0;
1959 const IS_SIMD = 1 << 1;
1960 const IS_TRANSPARENT = 1 << 2;
1961 // Internal only for now. If true, don't reorder fields.
1962 const IS_LINEAR = 1 << 3;
1964 // Any of these flags being set prevent field reordering optimisation.
1965 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1966 ReprFlags::IS_SIMD.bits |
1967 ReprFlags::IS_LINEAR.bits;
1971 impl_stable_hash_for!(struct ReprFlags {
1977 /// Represents the repr options provided by the user,
1978 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1979 pub struct ReprOptions {
1980 pub int: Option<attr::IntType>,
1983 pub flags: ReprFlags,
1986 impl_stable_hash_for!(struct ReprOptions {
1994 pub fn new(tcx: TyCtxt<'_, '_, '_>, did: DefId) -> ReprOptions {
1995 let mut flags = ReprFlags::empty();
1996 let mut size = None;
1997 let mut max_align = 0;
1998 let mut min_pack = 0;
1999 for attr in tcx.get_attrs(did).iter() {
2000 for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
2001 flags.insert(match r {
2002 attr::ReprC => ReprFlags::IS_C,
2003 attr::ReprPacked(pack) => {
2004 min_pack = if min_pack > 0 {
2005 cmp::min(pack, min_pack)
2011 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
2012 attr::ReprSimd => ReprFlags::IS_SIMD,
2013 attr::ReprInt(i) => {
2017 attr::ReprAlign(align) => {
2018 max_align = cmp::max(align, max_align);
2025 // This is here instead of layout because the choice must make it into metadata.
2026 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
2027 flags.insert(ReprFlags::IS_LINEAR);
2029 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
2033 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
2035 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
2037 pub fn packed(&self) -> bool { self.pack > 0 }
2039 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
2041 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
2043 pub fn discr_type(&self) -> attr::IntType {
2044 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
2047 /// Returns `true` if this `#[repr()]` should inhabit "smart enum
2048 /// layout" optimizations, such as representing `Foo<&T>` as a
2050 pub fn inhibit_enum_layout_opt(&self) -> bool {
2051 self.c() || self.int.is_some()
2054 /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
2055 /// optimizations, such as with repr(C) or repr(packed(1)).
2056 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
2057 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
2060 /// Returns true if this `#[repr()]` should inhibit union abi optimisations
2061 pub fn inhibit_union_abi_opt(&self) -> bool {
2067 impl<'a, 'gcx, 'tcx> AdtDef {
2068 fn new(tcx: TyCtxt<'_, '_, '_>,
2071 variants: IndexVec<VariantIdx, VariantDef>,
2072 repr: ReprOptions) -> Self {
2073 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
2074 let mut flags = AdtFlags::NO_ADT_FLAGS;
2075 let attrs = tcx.get_attrs(did);
2076 if attr::contains_name(&attrs, "fundamental") {
2077 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2079 if Some(did) == tcx.lang_items().phantom_data() {
2080 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2082 if Some(did) == tcx.lang_items().owned_box() {
2083 flags = flags | AdtFlags::IS_BOX;
2085 if Some(did) == tcx.lang_items().arc() {
2086 flags = flags | AdtFlags::IS_ARC;
2088 if Some(did) == tcx.lang_items().rc() {
2089 flags = flags | AdtFlags::IS_RC;
2091 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2092 debug!("found non-exhaustive variant list for {:?}", did);
2093 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2096 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2097 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2098 AdtKind::Struct => {}
2109 pub fn is_struct(&self) -> bool {
2110 !self.is_union() && !self.is_enum()
2114 pub fn is_union(&self) -> bool {
2115 self.flags.intersects(AdtFlags::IS_UNION)
2119 pub fn is_enum(&self) -> bool {
2120 self.flags.intersects(AdtFlags::IS_ENUM)
2124 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2125 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2128 /// Returns the kind of the ADT - Struct or Enum.
2130 pub fn adt_kind(&self) -> AdtKind {
2133 } else if self.is_union() {
2140 pub fn descr(&self) -> &'static str {
2141 match self.adt_kind() {
2142 AdtKind::Struct => "struct",
2143 AdtKind::Union => "union",
2144 AdtKind::Enum => "enum",
2148 pub fn variant_descr(&self) -> &'static str {
2149 match self.adt_kind() {
2150 AdtKind::Struct => "struct",
2151 AdtKind::Union => "union",
2152 AdtKind::Enum => "variant",
2156 /// Returns whether this type is #[fundamental] for the purposes
2157 /// of coherence checking.
2159 pub fn is_fundamental(&self) -> bool {
2160 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2163 /// Returns `true` if this is PhantomData<T>.
2165 pub fn is_phantom_data(&self) -> bool {
2166 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
2169 /// Returns `true` if this is `Arc<T>`.
2170 pub fn is_arc(&self) -> bool {
2171 self.flags.intersects(AdtFlags::IS_ARC)
2174 /// Returns `true` if this is `Rc<T>`.
2175 pub fn is_rc(&self) -> bool {
2176 self.flags.intersects(AdtFlags::IS_RC)
2179 /// Returns `true` if this is Box<T>.
2181 pub fn is_box(&self) -> bool {
2182 self.flags.intersects(AdtFlags::IS_BOX)
2185 /// Returns whether this type has a destructor.
2186 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2187 self.destructor(tcx).is_some()
2190 /// Asserts this is a struct or union and returns its unique variant.
2191 pub fn non_enum_variant(&self) -> &VariantDef {
2192 assert!(self.is_struct() || self.is_union());
2193 &self.variants[VariantIdx::new(0)]
2197 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Lrc<GenericPredicates<'gcx>> {
2198 tcx.predicates_of(self.did)
2201 /// Returns an iterator over all fields contained
2204 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2205 self.variants.iter().flat_map(|v| v.fields.iter())
2208 pub fn is_payloadfree(&self) -> bool {
2209 !self.variants.is_empty() &&
2210 self.variants.iter().all(|v| v.fields.is_empty())
2213 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2216 .find(|v| v.did == vid)
2217 .expect("variant_with_id: unknown variant")
2220 pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
2223 .find(|(_, v)| v.did == vid)
2224 .expect("variant_index_with_id: unknown variant")
2228 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2230 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2231 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2232 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2233 Def::SelfCtor(..) => self.non_enum_variant(),
2234 _ => bug!("unexpected def {:?} in variant_of_def", def)
2239 pub fn eval_explicit_discr(
2241 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2243 ) -> Option<Discr<'tcx>> {
2244 let param_env = ParamEnv::empty();
2245 let repr_type = self.repr.discr_type();
2246 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2247 let instance = ty::Instance::new(expr_did, substs);
2248 let cid = GlobalId {
2252 match tcx.const_eval(param_env.and(cid)) {
2254 // FIXME: Find the right type and use it instead of `val.ty` here
2255 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2256 trace!("discriminants: {} ({:?})", b, repr_type);
2262 info!("invalid enum discriminant: {:#?}", val);
2263 ::mir::interpret::struct_error(
2264 tcx.at(tcx.def_span(expr_did)),
2265 "constant evaluation of enum discriminant resulted in non-integer",
2270 Err(ErrorHandled::Reported) => {
2271 if !expr_did.is_local() {
2272 span_bug!(tcx.def_span(expr_did),
2273 "variant discriminant evaluation succeeded \
2274 in its crate but failed locally");
2278 Err(ErrorHandled::TooGeneric) => span_bug!(
2279 tcx.def_span(expr_did),
2280 "enum discriminant depends on generic arguments",
2286 pub fn discriminants(
2288 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2289 ) -> impl Iterator<Item=(VariantIdx, Discr<'tcx>)> + Captures<'gcx> + 'a {
2290 let repr_type = self.repr.discr_type();
2291 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2292 let mut prev_discr = None::<Discr<'tcx>>;
2293 self.variants.iter_enumerated().map(move |(i, v)| {
2294 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2295 if let VariantDiscr::Explicit(expr_did) = v.discr {
2296 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2300 prev_discr = Some(discr);
2306 /// Compute the discriminant value used by a specific variant.
2307 /// Unlike `discriminants`, this is (amortized) constant-time,
2308 /// only doing at most one query for evaluating an explicit
2309 /// discriminant (the last one before the requested variant),
2310 /// assuming there are no constant-evaluation errors there.
2311 pub fn discriminant_for_variant(&self,
2312 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2313 variant_index: VariantIdx)
2315 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2316 let explicit_value = val
2317 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2318 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2319 explicit_value.checked_add(tcx, offset as u128).0
2322 /// Yields a DefId for the discriminant and an offset to add to it
2323 /// Alternatively, if there is no explicit discriminant, returns the
2324 /// inferred discriminant directly
2325 pub fn discriminant_def_for_variant(
2327 variant_index: VariantIdx,
2328 ) -> (Option<DefId>, u32) {
2329 let mut explicit_index = variant_index.as_u32();
2332 match self.variants[VariantIdx::from_u32(explicit_index)].discr {
2333 ty::VariantDiscr::Relative(0) => {
2337 ty::VariantDiscr::Relative(distance) => {
2338 explicit_index -= distance;
2340 ty::VariantDiscr::Explicit(did) => {
2341 expr_did = Some(did);
2346 (expr_did, variant_index.as_u32() - explicit_index)
2349 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2350 tcx.adt_destructor(self.did)
2353 /// Returns a list of types such that `Self: Sized` if and only
2354 /// if that type is Sized, or `TyErr` if this type is recursive.
2356 /// Oddly enough, checking that the sized-constraint is Sized is
2357 /// actually more expressive than checking all members:
2358 /// the Sized trait is inductive, so an associated type that references
2359 /// Self would prevent its containing ADT from being Sized.
2361 /// Due to normalization being eager, this applies even if
2362 /// the associated type is behind a pointer, e.g. issue #31299.
2363 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2364 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2367 debug!("adt_sized_constraint: {:?} is recursive", self);
2368 // This should be reported as an error by `check_representable`.
2370 // Consider the type as Sized in the meanwhile to avoid
2371 // further errors. Delay our `bug` diagnostic here to get
2372 // emitted later as well in case we accidentally otherwise don't
2375 tcx.intern_type_list(&[tcx.types.err])
2380 fn sized_constraint_for_ty(&self,
2381 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2384 let result = match ty.sty {
2385 Bool | Char | Int(..) | Uint(..) | Float(..) |
2386 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2387 Array(..) | Closure(..) | Generator(..) | Never => {
2396 GeneratorWitness(..) => {
2397 // these are never sized - return the target type
2404 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2408 Adt(adt, substs) => {
2410 let adt_tys = adt.sized_constraint(tcx);
2411 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2414 .map(|ty| ty.subst(tcx, substs))
2415 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2419 Projection(..) | Opaque(..) => {
2420 // must calculate explicitly.
2421 // FIXME: consider special-casing always-Sized projections
2425 UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
2428 // perf hack: if there is a `T: Sized` bound, then
2429 // we know that `T` is Sized and do not need to check
2432 let sized_trait = match tcx.lang_items().sized_trait() {
2434 _ => return vec![ty]
2436 let sized_predicate = Binder::dummy(TraitRef {
2437 def_id: sized_trait,
2438 substs: tcx.mk_substs_trait(ty, &[])
2440 let predicates = &tcx.predicates_of(self.did).predicates;
2441 if predicates.iter().any(|(p, _)| *p == sized_predicate) {
2450 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2454 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2459 impl<'a, 'gcx, 'tcx> FieldDef {
2460 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2461 tcx.type_of(self.did).subst(tcx, subst)
2465 /// Represents the various closure traits in the Rust language. This
2466 /// will determine the type of the environment (`self`, in the
2467 /// desugaring) argument that the closure expects.
2469 /// You can get the environment type of a closure using
2470 /// `tcx.closure_env_ty()`.
2471 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2472 pub enum ClosureKind {
2473 // Warning: Ordering is significant here! The ordering is chosen
2474 // because the trait Fn is a subtrait of FnMut and so in turn, and
2475 // hence we order it so that Fn < FnMut < FnOnce.
2481 impl<'a, 'tcx> ClosureKind {
2482 // This is the initial value used when doing upvar inference.
2483 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2485 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2487 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2488 ClosureKind::FnMut => {
2489 tcx.require_lang_item(FnMutTraitLangItem)
2491 ClosureKind::FnOnce => {
2492 tcx.require_lang_item(FnOnceTraitLangItem)
2497 /// Returns `true` if this a type that impls this closure kind
2498 /// must also implement `other`.
2499 pub fn extends(self, other: ty::ClosureKind) -> bool {
2500 match (self, other) {
2501 (ClosureKind::Fn, ClosureKind::Fn) => true,
2502 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2503 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2504 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2505 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2506 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2511 /// Returns the representative scalar type for this closure kind.
2512 /// See `TyS::to_opt_closure_kind` for more details.
2513 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2515 ty::ClosureKind::Fn => tcx.types.i8,
2516 ty::ClosureKind::FnMut => tcx.types.i16,
2517 ty::ClosureKind::FnOnce => tcx.types.i32,
2522 impl<'tcx> TyS<'tcx> {
2523 /// Iterator that walks `self` and any types reachable from
2524 /// `self`, in depth-first order. Note that just walks the types
2525 /// that appear in `self`, it does not descend into the fields of
2526 /// structs or variants. For example:
2529 /// isize => { isize }
2530 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2531 /// [isize] => { [isize], isize }
2533 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2534 TypeWalker::new(self)
2537 /// Iterator that walks the immediate children of `self`. Hence
2538 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2539 /// (but not `i32`, like `walk`).
2540 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2541 walk::walk_shallow(self)
2544 /// Walks `ty` and any types appearing within `ty`, invoking the
2545 /// callback `f` on each type. If the callback returns false, then the
2546 /// children of the current type are ignored.
2548 /// Note: prefer `ty.walk()` where possible.
2549 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2550 where F: FnMut(Ty<'tcx>) -> bool
2552 let mut walker = self.walk();
2553 while let Some(ty) = walker.next() {
2555 walker.skip_current_subtree();
2562 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2564 hir::MutMutable => MutBorrow,
2565 hir::MutImmutable => ImmBorrow,
2569 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2570 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2571 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2573 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2575 MutBorrow => hir::MutMutable,
2576 ImmBorrow => hir::MutImmutable,
2578 // We have no type corresponding to a unique imm borrow, so
2579 // use `&mut`. It gives all the capabilities of an `&uniq`
2580 // and hence is a safe "over approximation".
2581 UniqueImmBorrow => hir::MutMutable,
2585 pub fn to_user_str(&self) -> &'static str {
2587 MutBorrow => "mutable",
2588 ImmBorrow => "immutable",
2589 UniqueImmBorrow => "uniquely immutable",
2594 #[derive(Debug, Clone)]
2595 pub enum Attributes<'gcx> {
2596 Owned(Lrc<[ast::Attribute]>),
2597 Borrowed(&'gcx [ast::Attribute])
2600 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2601 type Target = [ast::Attribute];
2603 fn deref(&self) -> &[ast::Attribute] {
2605 &Attributes::Owned(ref data) => &data,
2606 &Attributes::Borrowed(data) => data
2611 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2612 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2613 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2616 /// Returns an iterator of the def-ids for all body-owners in this
2617 /// crate. If you would prefer to iterate over the bodies
2618 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2621 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2625 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2628 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2629 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2630 f(self.hir.body_owner_def_id(body_id))
2634 pub fn expr_span(self, id: NodeId) -> Span {
2635 match self.hir.find(id) {
2636 Some(Node::Expr(e)) => {
2640 bug!("Node id {} is not an expr: {:?}", id, f);
2643 bug!("Node id {} is not present in the node map", id);
2648 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2649 self.associated_items(id)
2650 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2654 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2655 self.associated_items(did).any(|item| {
2656 item.relevant_for_never()
2660 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2661 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2662 match self.hir.get(node_id) {
2663 Node::TraitItem(_) | Node::ImplItem(_) => true,
2667 match self.describe_def(def_id).expect("no def for def-id") {
2668 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2673 if is_associated_item {
2674 Some(self.associated_item(def_id))
2680 fn associated_item_from_trait_item_ref(self,
2681 parent_def_id: DefId,
2682 parent_vis: &hir::Visibility,
2683 trait_item_ref: &hir::TraitItemRef)
2685 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2686 let (kind, has_self) = match trait_item_ref.kind {
2687 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2688 hir::AssociatedItemKind::Method { has_self } => {
2689 (ty::AssociatedKind::Method, has_self)
2691 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2692 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2696 ident: trait_item_ref.ident,
2698 // Visibility of trait items is inherited from their traits.
2699 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2700 defaultness: trait_item_ref.defaultness,
2702 container: TraitContainer(parent_def_id),
2703 method_has_self_argument: has_self
2707 fn associated_item_from_impl_item_ref(self,
2708 parent_def_id: DefId,
2709 impl_item_ref: &hir::ImplItemRef)
2711 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2712 let (kind, has_self) = match impl_item_ref.kind {
2713 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2714 hir::AssociatedItemKind::Method { has_self } => {
2715 (ty::AssociatedKind::Method, has_self)
2717 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2718 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2722 ident: impl_item_ref.ident,
2724 // Visibility of trait impl items doesn't matter.
2725 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2726 defaultness: impl_item_ref.defaultness,
2728 container: ImplContainer(parent_def_id),
2729 method_has_self_argument: has_self
2733 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables<'_>) -> usize {
2734 let hir_id = self.hir.node_to_hir_id(node_id);
2735 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2738 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2739 variant.fields.iter().position(|field| {
2740 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2744 pub fn associated_items(
2747 ) -> AssociatedItemsIterator<'a, 'gcx, 'tcx> {
2748 // Ideally, we would use `-> impl Iterator` here, but it falls
2749 // afoul of the conservative "capture [restrictions]" we put
2750 // in place, so we use a hand-written iterator.
2752 // [restrictions]: https://github.com/rust-lang/rust/issues/34511#issuecomment-373423999
2753 AssociatedItemsIterator {
2755 def_ids: self.associated_item_def_ids(def_id),
2760 /// Returns `true` if the impls are the same polarity and the trait either
2761 /// has no items or is annotated #[marker] and prevents item overrides.
2762 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2763 if self.features().overlapping_marker_traits {
2764 let trait1_is_empty = self.impl_trait_ref(def_id1)
2765 .map_or(false, |trait_ref| {
2766 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2768 let trait2_is_empty = self.impl_trait_ref(def_id2)
2769 .map_or(false, |trait_ref| {
2770 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2772 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2775 } else if self.features().marker_trait_attr {
2776 let is_marker_impl = |def_id: DefId| -> bool {
2777 let trait_ref = self.impl_trait_ref(def_id);
2778 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
2780 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2781 && is_marker_impl(def_id1)
2782 && is_marker_impl(def_id2)
2788 // Returns `ty::VariantDef` if `def` refers to a struct,
2789 // or variant or their constructors, panics otherwise.
2790 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2792 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2793 let enum_did = self.parent_def_id(did).unwrap();
2794 self.adt_def(enum_did).variant_with_id(did)
2796 Def::Struct(did) | Def::Union(did) => {
2797 self.adt_def(did).non_enum_variant()
2799 Def::StructCtor(ctor_did, ..) => {
2800 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2801 self.adt_def(did).non_enum_variant()
2803 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2807 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2808 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2809 let def_key = self.def_key(variant_def.did);
2810 match def_key.disambiguated_data.data {
2811 // for enum variants and tuple structs, the def-id of the ADT itself
2812 // is the *parent* of the variant
2813 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2814 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2816 // otherwise, for structs and unions, they share a def-id
2817 _ => variant_def.did,
2821 pub fn item_name(self, id: DefId) -> InternedString {
2822 if id.index == CRATE_DEF_INDEX {
2823 self.original_crate_name(id.krate).as_interned_str()
2825 let def_key = self.def_key(id);
2826 // The name of a StructCtor is that of its struct parent.
2827 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2828 self.item_name(DefId {
2830 index: def_key.parent.unwrap()
2833 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2834 bug!("item_name: no name for {:?}", self.def_path(id));
2840 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2841 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2845 ty::InstanceDef::Item(did) => {
2846 self.optimized_mir(did)
2848 ty::InstanceDef::VtableShim(..) |
2849 ty::InstanceDef::Intrinsic(..) |
2850 ty::InstanceDef::FnPtrShim(..) |
2851 ty::InstanceDef::Virtual(..) |
2852 ty::InstanceDef::ClosureOnceShim { .. } |
2853 ty::InstanceDef::DropGlue(..) |
2854 ty::InstanceDef::CloneShim(..) => {
2855 self.mir_shims(instance)
2860 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2861 /// Returns None if there is no MIR for the DefId
2862 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2863 if self.is_mir_available(did) {
2864 Some(self.optimized_mir(did))
2870 /// Get the attributes of a definition.
2871 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2872 if let Some(id) = self.hir.as_local_node_id(did) {
2873 Attributes::Borrowed(self.hir.attrs(id))
2875 Attributes::Owned(self.item_attrs(did))
2879 /// Determine whether an item is annotated with an attribute.
2880 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2881 attr::contains_name(&self.get_attrs(did), attr)
2884 /// Returns `true` if this is an `auto trait`.
2885 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2886 self.trait_def(trait_def_id).has_auto_impl
2889 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2890 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2893 /// Given the def-id of an impl, return the def_id of the trait it implements.
2894 /// If it implements no trait, return `None`.
2895 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2896 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2899 /// If the given defid describes a method belonging to an impl, return the
2900 /// def-id of the impl that the method belongs to. Otherwise, return `None`.
2901 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2902 let item = if def_id.krate != LOCAL_CRATE {
2903 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2904 Some(self.associated_item(def_id))
2909 self.opt_associated_item(def_id)
2912 item.and_then(|trait_item|
2913 match trait_item.container {
2914 TraitContainer(_) => None,
2915 ImplContainer(def_id) => Some(def_id),
2920 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2921 /// with the name of the crate containing the impl.
2922 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2923 if impl_did.is_local() {
2924 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2925 Ok(self.hir.span(node_id))
2927 Err(self.crate_name(impl_did.krate))
2931 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2932 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2933 // definition's parent/scope to perform comparison.
2934 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2935 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2938 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2939 ident = ident.modern();
2940 let target_expansion = match scope.krate {
2941 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2944 let scope = match ident.span.adjust(target_expansion) {
2945 Some(actual_expansion) =>
2946 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2947 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2948 None => self.hir.get_module_parent(block),
2954 pub struct AssociatedItemsIterator<'a, 'gcx: 'tcx, 'tcx: 'a> {
2955 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2956 def_ids: Lrc<Vec<DefId>>,
2960 impl Iterator for AssociatedItemsIterator<'_, '_, '_> {
2961 type Item = AssociatedItem;
2963 fn next(&mut self) -> Option<AssociatedItem> {
2964 let def_id = self.def_ids.get(self.next_index)?;
2965 self.next_index += 1;
2966 Some(self.tcx.associated_item(*def_id))
2970 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2971 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2972 F: FnOnce(&[hir::Freevar]) -> T,
2974 let def_id = self.hir.local_def_id(fid);
2975 match self.freevars(def_id) {
2982 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> AssociatedItem {
2983 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2984 let parent_id = tcx.hir.get_parent(id);
2985 let parent_def_id = tcx.hir.local_def_id(parent_id);
2986 let parent_item = tcx.hir.expect_item(parent_id);
2987 match parent_item.node {
2988 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2989 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2990 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2992 debug_assert_eq!(assoc_item.def_id, def_id);
2997 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2998 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2999 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
3002 debug_assert_eq!(assoc_item.def_id, def_id);
3010 span_bug!(parent_item.span,
3011 "unexpected parent of trait or impl item or item not found: {:?}",
3015 /// Calculates the Sized-constraint.
3017 /// In fact, there are only a few options for the types in the constraint:
3018 /// - an obviously-unsized type
3019 /// - a type parameter or projection whose Sizedness can't be known
3020 /// - a tuple of type parameters or projections, if there are multiple
3022 /// - a Error, if a type contained itself. The representability
3023 /// check should catch this case.
3024 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3026 -> &'tcx [Ty<'tcx>] {
3027 let def = tcx.adt_def(def_id);
3029 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
3032 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
3035 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
3040 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3042 -> Lrc<Vec<DefId>> {
3043 let id = tcx.hir.as_local_node_id(def_id).unwrap();
3044 let item = tcx.hir.expect_item(id);
3045 let vec: Vec<_> = match item.node {
3046 hir::ItemKind::Trait(.., ref trait_item_refs) => {
3047 trait_item_refs.iter()
3048 .map(|trait_item_ref| trait_item_ref.id)
3049 .map(|id| tcx.hir.local_def_id(id.node_id))
3052 hir::ItemKind::Impl(.., ref impl_item_refs) => {
3053 impl_item_refs.iter()
3054 .map(|impl_item_ref| impl_item_ref.id)
3055 .map(|id| tcx.hir.local_def_id(id.node_id))
3058 hir::ItemKind::TraitAlias(..) => vec![],
3059 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
3064 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
3065 tcx.hir.span_if_local(def_id).unwrap()
3068 /// If the given def ID describes an item belonging to a trait,
3069 /// return the ID of the trait that the trait item belongs to.
3070 /// Otherwise, return `None`.
3071 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
3072 tcx.opt_associated_item(def_id)
3073 .and_then(|associated_item| {
3074 match associated_item.container {
3075 TraitContainer(def_id) => Some(def_id),
3076 ImplContainer(_) => None
3081 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
3082 pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefId> {
3083 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3084 if let Node::Item(item) = tcx.hir.get(node_id) {
3085 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
3086 return exist_ty.impl_trait_fn;
3093 /// Returns `true` if `def_id` is a trait alias.
3094 pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
3095 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
3096 if let Node::Item(item) = tcx.hir.get(node_id) {
3097 if let hir::ItemKind::TraitAlias(..) = item.node {
3105 /// See `ParamEnv` struct definition for details.
3106 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3110 // The param_env of an impl Trait type is its defining function's param_env
3111 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
3112 return param_env(tcx, parent);
3114 // Compute the bounds on Self and the type parameters.
3116 let InstantiatedPredicates { predicates } =
3117 tcx.predicates_of(def_id).instantiate_identity(tcx);
3119 // Finally, we have to normalize the bounds in the environment, in
3120 // case they contain any associated type projections. This process
3121 // can yield errors if the put in illegal associated types, like
3122 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
3123 // report these errors right here; this doesn't actually feel
3124 // right to me, because constructing the environment feels like a
3125 // kind of a "idempotent" action, but I'm not sure where would be
3126 // a better place. In practice, we construct environments for
3127 // every fn once during type checking, and we'll abort if there
3128 // are any errors at that point, so after type checking you can be
3129 // sure that this will succeed without errors anyway.
3131 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
3132 traits::Reveal::UserFacing);
3134 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
3135 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
3137 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
3138 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3141 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3142 crate_num: CrateNum) -> CrateDisambiguator {
3143 assert_eq!(crate_num, LOCAL_CRATE);
3144 tcx.sess.local_crate_disambiguator()
3147 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3148 crate_num: CrateNum) -> Symbol {
3149 assert_eq!(crate_num, LOCAL_CRATE);
3150 tcx.crate_name.clone()
3153 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3154 crate_num: CrateNum)
3156 assert_eq!(crate_num, LOCAL_CRATE);
3160 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3161 instance_def: InstanceDef<'tcx>)
3163 match instance_def {
3164 InstanceDef::Item(..) |
3165 InstanceDef::DropGlue(..) => {
3166 let mir = tcx.instance_mir(instance_def);
3167 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3169 // Estimate the size of other compiler-generated shims to be 1.
3174 pub fn provide(providers: &mut ty::query::Providers<'_>) {
3175 context::provide(providers);
3176 erase_regions::provide(providers);
3177 layout::provide(providers);
3178 util::provide(providers);
3179 constness::provide(providers);
3180 *providers = ty::query::Providers {
3182 associated_item_def_ids,
3183 adt_sized_constraint,
3187 crate_disambiguator,
3188 original_crate_name,
3190 trait_impls_of: trait_def::trait_impls_of_provider,
3191 instance_def_size_estimate,
3196 /// A map for the local crate mapping each type to a vector of its
3197 /// inherent impls. This is not meant to be used outside of coherence;
3198 /// rather, you should request the vector for a specific type via
3199 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3200 /// (constructing this map requires touching the entire crate).
3201 #[derive(Clone, Debug, Default)]
3202 pub struct CrateInherentImpls {
3203 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3206 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3207 pub struct SymbolName {
3208 // FIXME: we don't rely on interning or equality here - better have
3209 // this be a `&'tcx str`.
3210 pub name: InternedString
3213 impl_stable_hash_for!(struct self::SymbolName {
3218 pub fn new(name: &str) -> SymbolName {
3220 name: Symbol::intern(name).as_interned_str()
3224 pub fn as_str(&self) -> LocalInternedString {
3229 impl fmt::Display for SymbolName {
3230 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3231 fmt::Display::fmt(&self.name, fmt)
3235 impl fmt::Debug for SymbolName {
3236 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
3237 fmt::Display::fmt(&self.name, fmt)