3182 lines
115 KiB
Rust
3182 lines
115 KiB
Rust
// ignore-tidy-filelength
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pub use self::fold::{TypeFoldable, TypeVisitor};
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pub use self::AssocItemContainer::*;
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pub use self::BorrowKind::*;
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pub use self::IntVarValue::*;
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pub use self::Variance::*;
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use crate::arena::Arena;
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use crate::hir::exports::ExportMap;
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use crate::ich::StableHashingContext;
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use crate::infer::canonical::Canonical;
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use crate::middle::cstore::CrateStoreDyn;
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use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
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use crate::mir::interpret::ErrorHandled;
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use crate::mir::GeneratorLayout;
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use crate::mir::ReadOnlyBodyAndCache;
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use crate::traits::{self, Reveal};
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use crate::ty;
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use crate::ty::subst::{InternalSubsts, Subst, SubstsRef};
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use crate::ty::util::{Discr, IntTypeExt};
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use crate::ty::walk::TypeWalker;
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use rustc_ast::ast::{self, Ident, Name};
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use rustc_ast::node_id::{NodeId, NodeMap, NodeSet};
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use rustc_attr as attr;
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use rustc_data_structures::captures::Captures;
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use rustc_data_structures::fingerprint::Fingerprint;
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use rustc_data_structures::fx::FxHashMap;
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use rustc_data_structures::fx::FxIndexMap;
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use rustc_data_structures::sorted_map::SortedIndexMultiMap;
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use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
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use rustc_data_structures::sync::{self, par_iter, Lrc, ParallelIterator};
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use rustc_hir as hir;
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use rustc_hir::def::{CtorKind, CtorOf, DefKind, Namespace, Res};
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use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
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use rustc_hir::lang_items::{FnMutTraitLangItem, FnOnceTraitLangItem, FnTraitLangItem};
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use rustc_hir::{Constness, GlobMap, Node, TraitMap};
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use rustc_index::vec::{Idx, IndexVec};
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use rustc_macros::HashStable;
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use rustc_serialize::{self, Encodable, Encoder};
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use rustc_session::DataTypeKind;
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use rustc_span::hygiene::ExpnId;
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use rustc_span::symbol::{kw, sym, Symbol};
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use rustc_span::Span;
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use rustc_target::abi::{Align, VariantIdx};
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use std::cell::RefCell;
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use std::cmp::{self, Ordering};
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use std::fmt;
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use std::hash::{Hash, Hasher};
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use std::ops::Deref;
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use std::ops::Range;
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use std::slice;
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use std::{mem, ptr};
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pub use self::sty::BoundRegion::*;
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pub use self::sty::InferTy::*;
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pub use self::sty::RegionKind;
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pub use self::sty::RegionKind::*;
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pub use self::sty::TyKind::*;
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pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
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pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
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pub use self::sty::{CanonicalPolyFnSig, FnSig, GenSig, PolyFnSig, PolyGenSig};
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pub use self::sty::{ClosureSubsts, GeneratorSubsts, TypeAndMut, UpvarSubsts};
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pub use self::sty::{Const, ConstKind, ExistentialProjection, PolyExistentialProjection};
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pub use self::sty::{ConstVid, FloatVid, IntVid, RegionVid, TyVid};
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pub use self::sty::{ExistentialPredicate, InferConst, InferTy, ParamConst, ParamTy, ProjectionTy};
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pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
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pub use self::sty::{PolyTraitRef, TraitRef, TyKind};
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pub use crate::ty::diagnostics::*;
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pub use self::binding::BindingMode;
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pub use self::binding::BindingMode::*;
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pub use self::context::{keep_local, tls, FreeRegionInfo, TyCtxt};
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pub use self::context::{
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CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
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UserType, UserTypeAnnotationIndex,
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};
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pub use self::context::{
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CtxtInterners, GeneratorInteriorTypeCause, GlobalCtxt, Lift, TypeckTables,
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};
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pub use self::instance::RESOLVE_INSTANCE;
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pub use self::instance::{Instance, InstanceDef};
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pub use self::trait_def::TraitDef;
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pub use self::query::queries;
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pub mod adjustment;
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pub mod binding;
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pub mod cast;
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#[macro_use]
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pub mod codec;
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pub mod _match;
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mod erase_regions;
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pub mod error;
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pub mod fast_reject;
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pub mod flags;
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pub mod fold;
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pub mod free_region_map;
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pub mod inhabitedness;
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pub mod layout;
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pub mod normalize_erasing_regions;
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pub mod outlives;
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pub mod print;
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pub mod query;
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pub mod relate;
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pub mod steal;
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pub mod subst;
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pub mod trait_def;
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pub mod util;
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pub mod walk;
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mod context;
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mod diagnostics;
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mod instance;
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mod structural_impls;
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mod sty;
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// Data types
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pub struct ResolverOutputs {
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pub definitions: rustc_hir::definitions::Definitions,
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pub cstore: Box<CrateStoreDyn>,
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pub extern_crate_map: NodeMap<CrateNum>,
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pub trait_map: TraitMap<NodeId>,
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pub maybe_unused_trait_imports: NodeSet,
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pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
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pub export_map: ExportMap<NodeId>,
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pub glob_map: GlobMap,
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/// Extern prelude entries. The value is `true` if the entry was introduced
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/// via `extern crate` item and not `--extern` option or compiler built-in.
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pub extern_prelude: FxHashMap<Name, bool>,
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}
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#[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
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pub enum AssocItemContainer {
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TraitContainer(DefId),
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ImplContainer(DefId),
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}
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impl AssocItemContainer {
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/// Asserts that this is the `DefId` of an associated item declared
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/// in a trait, and returns the trait `DefId`.
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pub fn assert_trait(&self) -> DefId {
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match *self {
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TraitContainer(id) => id,
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_ => bug!("associated item has wrong container type: {:?}", self),
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}
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}
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pub fn id(&self) -> DefId {
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match *self {
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TraitContainer(id) => id,
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ImplContainer(id) => id,
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}
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}
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}
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/// The "header" of an impl is everything outside the body: a Self type, a trait
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/// ref (in the case of a trait impl), and a set of predicates (from the
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/// bounds / where-clauses).
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#[derive(Clone, Debug, TypeFoldable)]
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pub struct ImplHeader<'tcx> {
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pub impl_def_id: DefId,
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pub self_ty: Ty<'tcx>,
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pub trait_ref: Option<TraitRef<'tcx>>,
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pub predicates: Vec<Predicate<'tcx>>,
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}
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#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
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pub enum ImplPolarity {
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/// `impl Trait for Type`
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Positive,
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/// `impl !Trait for Type`
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Negative,
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/// `#[rustc_reservation_impl] impl Trait for Type`
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///
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/// This is a "stability hack", not a real Rust feature.
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/// See #64631 for details.
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Reservation,
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}
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#[derive(Copy, Clone, Debug, PartialEq, HashStable)]
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pub struct AssocItem {
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pub def_id: DefId,
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#[stable_hasher(project(name))]
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pub ident: Ident,
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pub kind: AssocKind,
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pub vis: Visibility,
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pub defaultness: hir::Defaultness,
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pub container: AssocItemContainer,
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/// Whether this is a method with an explicit self
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/// as its first argument, allowing method calls.
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pub method_has_self_argument: bool,
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}
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#[derive(Copy, Clone, PartialEq, Debug, HashStable)]
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pub enum AssocKind {
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Const,
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Method,
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OpaqueTy,
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Type,
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}
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impl AssocKind {
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pub fn suggestion_descr(&self) -> &'static str {
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match self {
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ty::AssocKind::Method => "method call",
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ty::AssocKind::Type | ty::AssocKind::OpaqueTy => "associated type",
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ty::AssocKind::Const => "associated constant",
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}
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}
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pub fn namespace(&self) -> Namespace {
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match *self {
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ty::AssocKind::OpaqueTy | ty::AssocKind::Type => Namespace::TypeNS,
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ty::AssocKind::Const | ty::AssocKind::Method => Namespace::ValueNS,
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}
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}
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}
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impl AssocItem {
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pub fn def_kind(&self) -> DefKind {
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match self.kind {
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AssocKind::Const => DefKind::AssocConst,
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AssocKind::Method => DefKind::AssocFn,
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AssocKind::Type => DefKind::AssocTy,
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AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
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}
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}
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/// Tests whether the associated item admits a non-trivial implementation
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/// for !
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pub fn relevant_for_never(&self) -> bool {
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match self.kind {
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AssocKind::OpaqueTy | AssocKind::Const | AssocKind::Type => true,
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// FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
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AssocKind::Method => !self.method_has_self_argument,
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}
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}
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pub fn signature(&self, tcx: TyCtxt<'_>) -> String {
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match self.kind {
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ty::AssocKind::Method => {
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// We skip the binder here because the binder would deanonymize all
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// late-bound regions, and we don't want method signatures to show up
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// `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
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// regions just fine, showing `fn(&MyType)`.
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tcx.fn_sig(self.def_id).skip_binder().to_string()
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}
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ty::AssocKind::Type => format!("type {};", self.ident),
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// FIXME(type_alias_impl_trait): we should print bounds here too.
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ty::AssocKind::OpaqueTy => format!("type {};", self.ident),
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ty::AssocKind::Const => {
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format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
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}
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}
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}
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}
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/// A list of `ty::AssocItem`s in definition order that allows for efficient lookup by name.
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///
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/// When doing lookup by name, we try to postpone hygienic comparison for as long as possible since
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/// it is relatively expensive. Instead, items are indexed by `Symbol` and hygienic comparison is
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/// done only on items with the same name.
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#[derive(Debug, Clone, PartialEq, HashStable)]
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pub struct AssociatedItems {
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items: SortedIndexMultiMap<u32, Symbol, ty::AssocItem>,
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}
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impl AssociatedItems {
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/// Constructs an `AssociatedItems` map from a series of `ty::AssocItem`s in definition order.
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pub fn new(items_in_def_order: impl IntoIterator<Item = ty::AssocItem>) -> Self {
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let items = items_in_def_order.into_iter().map(|item| (item.ident.name, item)).collect();
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AssociatedItems { items }
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}
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/// Returns a slice of associated items in the order they were defined.
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///
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/// New code should avoid relying on definition order. If you need a particular associated item
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/// for a known trait, make that trait a lang item instead of indexing this array.
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pub fn in_definition_order(&self) -> impl '_ + Iterator<Item = &ty::AssocItem> {
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self.items.iter().map(|(_, v)| v)
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}
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/// Returns an iterator over all associated items with the given name, ignoring hygiene.
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pub fn filter_by_name_unhygienic(
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&self,
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name: Symbol,
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) -> impl '_ + Iterator<Item = &ty::AssocItem> {
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self.items.get_by_key(&name)
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}
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/// Returns an iterator over all associated items with the given name.
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///
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/// Multiple items may have the same name if they are in different `Namespace`s. For example,
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/// an associated type can have the same name as a method. Use one of the `find_by_name_and_*`
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/// methods below if you know which item you are looking for.
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pub fn filter_by_name(
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&'a self,
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tcx: TyCtxt<'a>,
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ident: Ident,
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parent_def_id: DefId,
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) -> impl 'a + Iterator<Item = &'a ty::AssocItem> {
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self.filter_by_name_unhygienic(ident.name)
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.filter(move |item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
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}
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/// Returns the associated item with the given name and `AssocKind`, if one exists.
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pub fn find_by_name_and_kind(
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&self,
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tcx: TyCtxt<'_>,
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ident: Ident,
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kind: AssocKind,
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parent_def_id: DefId,
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) -> Option<&ty::AssocItem> {
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self.filter_by_name_unhygienic(ident.name)
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.filter(|item| item.kind == kind)
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.find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
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}
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/// Returns the associated item with the given name in the given `Namespace`, if one exists.
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pub fn find_by_name_and_namespace(
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&self,
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tcx: TyCtxt<'_>,
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ident: Ident,
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ns: Namespace,
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parent_def_id: DefId,
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) -> Option<&ty::AssocItem> {
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self.filter_by_name_unhygienic(ident.name)
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.filter(|item| item.kind.namespace() == ns)
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.find(|item| tcx.hygienic_eq(ident, item.ident, parent_def_id))
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}
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}
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#[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable, HashStable)]
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pub enum Visibility {
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/// Visible everywhere (including in other crates).
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Public,
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/// Visible only in the given crate-local module.
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Restricted(DefId),
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/// Not visible anywhere in the local crate. This is the visibility of private external items.
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Invisible,
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}
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pub trait DefIdTree: Copy {
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fn parent(self, id: DefId) -> Option<DefId>;
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fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
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if descendant.krate != ancestor.krate {
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return false;
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}
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while descendant != ancestor {
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match self.parent(descendant) {
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Some(parent) => descendant = parent,
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None => return false,
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}
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}
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true
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}
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}
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impl<'tcx> DefIdTree for TyCtxt<'tcx> {
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fn parent(self, id: DefId) -> Option<DefId> {
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self.def_key(id).parent.map(|index| DefId { index, ..id })
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}
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}
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impl Visibility {
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pub fn from_hir(visibility: &hir::Visibility<'_>, id: hir::HirId, tcx: TyCtxt<'_>) -> Self {
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match visibility.node {
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hir::VisibilityKind::Public => Visibility::Public,
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hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
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hir::VisibilityKind::Restricted { ref path, .. } => match path.res {
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// If there is no resolution, `resolve` will have already reported an error, so
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// assume that the visibility is public to avoid reporting more privacy errors.
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Res::Err => Visibility::Public,
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def => Visibility::Restricted(def.def_id()),
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},
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hir::VisibilityKind::Inherited => {
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Visibility::Restricted(tcx.parent_module(id).to_def_id())
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}
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}
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}
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/// Returns `true` if an item with this visibility is accessible from the given block.
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pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
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let restriction = match self {
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// Public items are visible everywhere.
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Visibility::Public => return true,
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// Private items from other crates are visible nowhere.
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Visibility::Invisible => return false,
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// Restricted items are visible in an arbitrary local module.
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Visibility::Restricted(other) if other.krate != module.krate => return false,
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Visibility::Restricted(module) => module,
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};
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tree.is_descendant_of(module, restriction)
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}
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/// Returns `true` if this visibility is at least as accessible as the given visibility
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pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
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let vis_restriction = match vis {
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Visibility::Public => return self == Visibility::Public,
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Visibility::Invisible => return true,
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Visibility::Restricted(module) => module,
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};
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self.is_accessible_from(vis_restriction, tree)
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}
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|
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// Returns `true` if this item is visible anywhere in the local crate.
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pub fn is_visible_locally(self) -> bool {
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match self {
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Visibility::Public => true,
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Visibility::Restricted(def_id) => def_id.is_local(),
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Visibility::Invisible => false,
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}
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}
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}
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#[derive(Copy, Clone, PartialEq, RustcDecodable, RustcEncodable, HashStable)]
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pub enum Variance {
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Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
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Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
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Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
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Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
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}
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/// The crate variances map is computed during typeck and contains the
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/// variance of every item in the local crate. You should not use it
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/// directly, because to do so will make your pass dependent on the
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/// HIR of every item in the local crate. Instead, use
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/// `tcx.variances_of()` to get the variance for a *particular*
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/// item.
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#[derive(HashStable)]
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pub struct CrateVariancesMap<'tcx> {
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/// For each item with generics, maps to a vector of the variance
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/// of its generics. If an item has no generics, it will have no
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/// entry.
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pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
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}
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impl Variance {
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/// `a.xform(b)` combines the variance of a context with the
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/// variance of a type with the following meaning. If we are in a
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/// context with variance `a`, and we encounter a type argument in
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/// a position with variance `b`, then `a.xform(b)` is the new
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/// variance with which the argument appears.
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///
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/// Example 1:
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///
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/// *mut Vec<i32>
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///
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/// Here, the "ambient" variance starts as covariant. `*mut T` is
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/// invariant with respect to `T`, so the variance in which the
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/// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
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/// yields `Invariant`. Now, the type `Vec<T>` is covariant with
|
|
/// respect to its type argument `T`, and hence the variance of
|
|
/// the `i32` here is `Invariant.xform(Covariant)`, which results
|
|
/// (again) in `Invariant`.
|
|
///
|
|
/// Example 2:
|
|
///
|
|
/// fn(*const Vec<i32>, *mut Vec<i32)
|
|
///
|
|
/// The ambient variance is covariant. A `fn` type is
|
|
/// contravariant with respect to its parameters, so the variance
|
|
/// within which both pointer types appear is
|
|
/// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
|
|
/// T` is covariant with respect to `T`, so the variance within
|
|
/// which the first `Vec<i32>` appears is
|
|
/// `Contravariant.xform(Covariant)` or `Contravariant`. The same
|
|
/// is true for its `i32` argument. In the `*mut T` case, the
|
|
/// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
|
|
/// and hence the outermost type is `Invariant` with respect to
|
|
/// `Vec<i32>` (and its `i32` argument).
|
|
///
|
|
/// Source: Figure 1 of "Taming the Wildcards:
|
|
/// Combining Definition- and Use-Site Variance" published in PLDI'11.
|
|
pub fn xform(self, v: ty::Variance) -> ty::Variance {
|
|
match (self, v) {
|
|
// Figure 1, column 1.
|
|
(ty::Covariant, ty::Covariant) => ty::Covariant,
|
|
(ty::Covariant, ty::Contravariant) => ty::Contravariant,
|
|
(ty::Covariant, ty::Invariant) => ty::Invariant,
|
|
(ty::Covariant, ty::Bivariant) => ty::Bivariant,
|
|
|
|
// Figure 1, column 2.
|
|
(ty::Contravariant, ty::Covariant) => ty::Contravariant,
|
|
(ty::Contravariant, ty::Contravariant) => ty::Covariant,
|
|
(ty::Contravariant, ty::Invariant) => ty::Invariant,
|
|
(ty::Contravariant, ty::Bivariant) => ty::Bivariant,
|
|
|
|
// Figure 1, column 3.
|
|
(ty::Invariant, _) => ty::Invariant,
|
|
|
|
// Figure 1, column 4.
|
|
(ty::Bivariant, _) => ty::Bivariant,
|
|
}
|
|
}
|
|
}
|
|
|
|
// Contains information needed to resolve types and (in the future) look up
|
|
// the types of AST nodes.
|
|
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
|
|
pub struct CReaderCacheKey {
|
|
pub cnum: CrateNum,
|
|
pub pos: usize,
|
|
}
|
|
|
|
bitflags! {
|
|
/// Flags that we track on types. These flags are propagated upwards
|
|
/// through the type during type construction, so that we can quickly check
|
|
/// whether the type has various kinds of types in it without recursing
|
|
/// over the type itself.
|
|
pub struct TypeFlags: u32 {
|
|
// Does this have parameters? Used to determine whether substitution is
|
|
// required.
|
|
/// Does this have [Param]?
|
|
const HAS_TY_PARAM = 1 << 0;
|
|
/// Does this have [ReEarlyBound]?
|
|
const HAS_RE_PARAM = 1 << 1;
|
|
/// Does this have [ConstKind::Param]?
|
|
const HAS_CT_PARAM = 1 << 2;
|
|
|
|
const NEEDS_SUBST = TypeFlags::HAS_TY_PARAM.bits
|
|
| TypeFlags::HAS_RE_PARAM.bits
|
|
| TypeFlags::HAS_CT_PARAM.bits;
|
|
|
|
/// Does this have [Infer]?
|
|
const HAS_TY_INFER = 1 << 3;
|
|
/// Does this have [ReVar]?
|
|
const HAS_RE_INFER = 1 << 4;
|
|
/// Does this have [ConstKind::Infer]?
|
|
const HAS_CT_INFER = 1 << 5;
|
|
|
|
/// Does this have inference variables? Used to determine whether
|
|
/// inference is required.
|
|
const NEEDS_INFER = TypeFlags::HAS_TY_INFER.bits
|
|
| TypeFlags::HAS_RE_INFER.bits
|
|
| TypeFlags::HAS_CT_INFER.bits;
|
|
|
|
/// Does this have [Placeholder]?
|
|
const HAS_TY_PLACEHOLDER = 1 << 6;
|
|
/// Does this have [RePlaceholder]?
|
|
const HAS_RE_PLACEHOLDER = 1 << 7;
|
|
/// Does this have [ConstKind::Placeholder]?
|
|
const HAS_CT_PLACEHOLDER = 1 << 8;
|
|
|
|
/// `true` if there are "names" of regions and so forth
|
|
/// that are local to a particular fn/inferctxt
|
|
const HAS_FREE_LOCAL_REGIONS = 1 << 9;
|
|
|
|
/// `true` if there are "names" of types and regions and so forth
|
|
/// that are local to a particular fn
|
|
const HAS_FREE_LOCAL_NAMES = TypeFlags::HAS_TY_PARAM.bits
|
|
| TypeFlags::HAS_CT_PARAM.bits
|
|
| TypeFlags::HAS_TY_INFER.bits
|
|
| TypeFlags::HAS_CT_INFER.bits
|
|
| TypeFlags::HAS_TY_PLACEHOLDER.bits
|
|
| TypeFlags::HAS_CT_PLACEHOLDER.bits
|
|
| TypeFlags::HAS_FREE_LOCAL_REGIONS.bits;
|
|
|
|
/// Does this have [Projection] or [UnnormalizedProjection]?
|
|
const HAS_TY_PROJECTION = 1 << 10;
|
|
/// Does this have [Opaque]?
|
|
const HAS_TY_OPAQUE = 1 << 11;
|
|
/// Does this have [ConstKind::Unevaluated]?
|
|
const HAS_CT_PROJECTION = 1 << 12;
|
|
|
|
/// Could this type be normalized further?
|
|
const HAS_PROJECTION = TypeFlags::HAS_TY_PROJECTION.bits
|
|
| TypeFlags::HAS_TY_OPAQUE.bits
|
|
| TypeFlags::HAS_CT_PROJECTION.bits;
|
|
|
|
/// Present if the type belongs in a local type context.
|
|
/// Set for placeholders and inference variables that are not "Fresh".
|
|
const KEEP_IN_LOCAL_TCX = 1 << 13;
|
|
|
|
/// Is an error type reachable?
|
|
const HAS_TY_ERR = 1 << 14;
|
|
|
|
/// Does this have any region that "appears free" in the type?
|
|
/// Basically anything but [ReLateBound] and [ReErased].
|
|
const HAS_FREE_REGIONS = 1 << 15;
|
|
|
|
/// Does this have any [ReLateBound] regions? Used to check
|
|
/// if a global bound is safe to evaluate.
|
|
const HAS_RE_LATE_BOUND = 1 << 16;
|
|
|
|
/// Does this have any [ReErased] regions?
|
|
const HAS_RE_ERASED = 1 << 17;
|
|
|
|
/// Does this value have parameters/placeholders/inference variables which could be
|
|
/// replaced later, in a way that would change the results of `impl` specialization?
|
|
const STILL_FURTHER_SPECIALIZABLE = 1 << 18;
|
|
|
|
/// Flags representing the nominal content of a type,
|
|
/// computed by FlagsComputation. If you add a new nominal
|
|
/// flag, it should be added here too.
|
|
const NOMINAL_FLAGS = TypeFlags::HAS_TY_PARAM.bits
|
|
| TypeFlags::HAS_RE_PARAM.bits
|
|
| TypeFlags::HAS_CT_PARAM.bits
|
|
| TypeFlags::HAS_TY_INFER.bits
|
|
| TypeFlags::HAS_RE_INFER.bits
|
|
| TypeFlags::HAS_CT_INFER.bits
|
|
| TypeFlags::HAS_TY_PLACEHOLDER.bits
|
|
| TypeFlags::HAS_RE_PLACEHOLDER.bits
|
|
| TypeFlags::HAS_CT_PLACEHOLDER.bits
|
|
| TypeFlags::HAS_FREE_LOCAL_REGIONS.bits
|
|
| TypeFlags::HAS_TY_PROJECTION.bits
|
|
| TypeFlags::HAS_TY_OPAQUE.bits
|
|
| TypeFlags::HAS_CT_PROJECTION.bits
|
|
| TypeFlags::KEEP_IN_LOCAL_TCX.bits
|
|
| TypeFlags::HAS_TY_ERR.bits
|
|
| TypeFlags::HAS_FREE_REGIONS.bits
|
|
| TypeFlags::HAS_RE_LATE_BOUND.bits
|
|
| TypeFlags::HAS_RE_ERASED.bits
|
|
| TypeFlags::STILL_FURTHER_SPECIALIZABLE.bits;
|
|
}
|
|
}
|
|
|
|
#[allow(rustc::usage_of_ty_tykind)]
|
|
pub struct TyS<'tcx> {
|
|
pub kind: TyKind<'tcx>,
|
|
pub flags: TypeFlags,
|
|
|
|
/// This is a kind of confusing thing: it stores the smallest
|
|
/// binder such that
|
|
///
|
|
/// (a) the binder itself captures nothing but
|
|
/// (b) all the late-bound things within the type are captured
|
|
/// by some sub-binder.
|
|
///
|
|
/// So, for a type without any late-bound things, like `u32`, this
|
|
/// will be *innermost*, because that is the innermost binder that
|
|
/// captures nothing. But for a type `&'D u32`, where `'D` is a
|
|
/// late-bound region with De Bruijn index `D`, this would be `D + 1`
|
|
/// -- the binder itself does not capture `D`, but `D` is captured
|
|
/// by an inner binder.
|
|
///
|
|
/// We call this concept an "exclusive" binder `D` because all
|
|
/// De Bruijn indices within the type are contained within `0..D`
|
|
/// (exclusive).
|
|
outer_exclusive_binder: ty::DebruijnIndex,
|
|
}
|
|
|
|
// `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
|
|
#[cfg(target_arch = "x86_64")]
|
|
static_assert_size!(TyS<'_>, 32);
|
|
|
|
impl<'tcx> Ord for TyS<'tcx> {
|
|
fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
|
|
self.kind.cmp(&other.kind)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> PartialOrd for TyS<'tcx> {
|
|
fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
|
|
Some(self.kind.cmp(&other.kind))
|
|
}
|
|
}
|
|
|
|
impl<'tcx> PartialEq for TyS<'tcx> {
|
|
#[inline]
|
|
fn eq(&self, other: &TyS<'tcx>) -> bool {
|
|
ptr::eq(self, other)
|
|
}
|
|
}
|
|
impl<'tcx> Eq for TyS<'tcx> {}
|
|
|
|
impl<'tcx> Hash for TyS<'tcx> {
|
|
fn hash<H: Hasher>(&self, s: &mut H) {
|
|
(self as *const TyS<'_>).hash(s)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
|
|
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
|
|
let ty::TyS {
|
|
ref kind,
|
|
|
|
// The other fields just provide fast access to information that is
|
|
// also contained in `kind`, so no need to hash them.
|
|
flags: _,
|
|
|
|
outer_exclusive_binder: _,
|
|
} = *self;
|
|
|
|
kind.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
#[rustc_diagnostic_item = "Ty"]
|
|
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
|
|
|
|
impl<'tcx> rustc_serialize::UseSpecializedEncodable for Ty<'tcx> {}
|
|
impl<'tcx> rustc_serialize::UseSpecializedDecodable for Ty<'tcx> {}
|
|
|
|
pub type CanonicalTy<'tcx> = Canonical<'tcx, Ty<'tcx>>;
|
|
|
|
extern "C" {
|
|
/// A dummy type used to force `List` to be unsized while not requiring references to it be wide
|
|
/// pointers.
|
|
type OpaqueListContents;
|
|
}
|
|
|
|
/// A wrapper for slices with the additional invariant
|
|
/// that the slice is interned and no other slice with
|
|
/// the same contents can exist in the same context.
|
|
/// This means we can use pointer for both
|
|
/// equality comparisons and hashing.
|
|
/// Note: `Slice` was already taken by the `Ty`.
|
|
#[repr(C)]
|
|
pub struct List<T> {
|
|
len: usize,
|
|
data: [T; 0],
|
|
opaque: OpaqueListContents,
|
|
}
|
|
|
|
unsafe impl<T: Sync> Sync for List<T> {}
|
|
|
|
impl<T: Copy> List<T> {
|
|
#[inline]
|
|
fn from_arena<'tcx>(arena: &'tcx Arena<'tcx>, slice: &[T]) -> &'tcx List<T> {
|
|
assert!(!mem::needs_drop::<T>());
|
|
assert!(mem::size_of::<T>() != 0);
|
|
assert!(!slice.is_empty());
|
|
|
|
// Align up the size of the len (usize) field
|
|
let align = mem::align_of::<T>();
|
|
let align_mask = align - 1;
|
|
let offset = mem::size_of::<usize>();
|
|
let offset = (offset + align_mask) & !align_mask;
|
|
|
|
let size = offset + slice.len() * mem::size_of::<T>();
|
|
|
|
let mem = arena
|
|
.dropless
|
|
.alloc_raw(size, cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
|
|
unsafe {
|
|
let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
|
|
// Write the length
|
|
result.len = slice.len();
|
|
|
|
// Write the elements
|
|
let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
|
|
arena_slice.copy_from_slice(slice);
|
|
|
|
result
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T: fmt::Debug> fmt::Debug for List<T> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
(**self).fmt(f)
|
|
}
|
|
}
|
|
|
|
impl<T: Encodable> Encodable for List<T> {
|
|
#[inline]
|
|
fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
|
|
(**self).encode(s)
|
|
}
|
|
}
|
|
|
|
impl<T> Ord for List<T>
|
|
where
|
|
T: Ord,
|
|
{
|
|
fn cmp(&self, other: &List<T>) -> Ordering {
|
|
if self == other { Ordering::Equal } else { <[T] as Ord>::cmp(&**self, &**other) }
|
|
}
|
|
}
|
|
|
|
impl<T> PartialOrd for List<T>
|
|
where
|
|
T: PartialOrd,
|
|
{
|
|
fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
|
|
if self == other {
|
|
Some(Ordering::Equal)
|
|
} else {
|
|
<[T] as PartialOrd>::partial_cmp(&**self, &**other)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T: PartialEq> PartialEq for List<T> {
|
|
#[inline]
|
|
fn eq(&self, other: &List<T>) -> bool {
|
|
ptr::eq(self, other)
|
|
}
|
|
}
|
|
impl<T: Eq> Eq for List<T> {}
|
|
|
|
impl<T> Hash for List<T> {
|
|
#[inline]
|
|
fn hash<H: Hasher>(&self, s: &mut H) {
|
|
(self as *const List<T>).hash(s)
|
|
}
|
|
}
|
|
|
|
impl<T> Deref for List<T> {
|
|
type Target = [T];
|
|
#[inline(always)]
|
|
fn deref(&self) -> &[T] {
|
|
self.as_ref()
|
|
}
|
|
}
|
|
|
|
impl<T> AsRef<[T]> for List<T> {
|
|
#[inline(always)]
|
|
fn as_ref(&self) -> &[T] {
|
|
unsafe { slice::from_raw_parts(self.data.as_ptr(), self.len) }
|
|
}
|
|
}
|
|
|
|
impl<'a, T> IntoIterator for &'a List<T> {
|
|
type Item = &'a T;
|
|
type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
|
|
#[inline(always)]
|
|
fn into_iter(self) -> Self::IntoIter {
|
|
self[..].iter()
|
|
}
|
|
}
|
|
|
|
impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
|
|
|
|
impl<T> List<T> {
|
|
#[inline(always)]
|
|
pub fn empty<'a>() -> &'a List<T> {
|
|
#[repr(align(64), C)]
|
|
struct EmptySlice([u8; 64]);
|
|
static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
|
|
assert!(mem::align_of::<T>() <= 64);
|
|
unsafe { &*(&EMPTY_SLICE as *const _ as *const List<T>) }
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub struct UpvarPath {
|
|
pub hir_id: hir::HirId,
|
|
}
|
|
|
|
/// Upvars do not get their own `NodeId`. Instead, we use the pair of
|
|
/// the original var ID (that is, the root variable that is referenced
|
|
/// by the upvar) and the ID of the closure expression.
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub struct UpvarId {
|
|
pub var_path: UpvarPath,
|
|
pub closure_expr_id: LocalDefId,
|
|
}
|
|
|
|
#[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, HashStable)]
|
|
pub enum BorrowKind {
|
|
/// Data must be immutable and is aliasable.
|
|
ImmBorrow,
|
|
|
|
/// Data must be immutable but not aliasable. This kind of borrow
|
|
/// cannot currently be expressed by the user and is used only in
|
|
/// implicit closure bindings. It is needed when the closure
|
|
/// is borrowing or mutating a mutable referent, e.g.:
|
|
///
|
|
/// let x: &mut isize = ...;
|
|
/// let y = || *x += 5;
|
|
///
|
|
/// If we were to try to translate this closure into a more explicit
|
|
/// form, we'd encounter an error with the code as written:
|
|
///
|
|
/// struct Env { x: & &mut isize }
|
|
/// let x: &mut isize = ...;
|
|
/// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
|
|
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
|
///
|
|
/// This is then illegal because you cannot mutate a `&mut` found
|
|
/// in an aliasable location. To solve, you'd have to translate with
|
|
/// an `&mut` borrow:
|
|
///
|
|
/// struct Env { x: & &mut isize }
|
|
/// let x: &mut isize = ...;
|
|
/// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
|
|
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
|
///
|
|
/// Now the assignment to `**env.x` is legal, but creating a
|
|
/// mutable pointer to `x` is not because `x` is not mutable. We
|
|
/// could fix this by declaring `x` as `let mut x`. This is ok in
|
|
/// user code, if awkward, but extra weird for closures, since the
|
|
/// borrow is hidden.
|
|
///
|
|
/// So we introduce a "unique imm" borrow -- the referent is
|
|
/// immutable, but not aliasable. This solves the problem. For
|
|
/// simplicity, we don't give users the way to express this
|
|
/// borrow, it's just used when translating closures.
|
|
UniqueImmBorrow,
|
|
|
|
/// Data is mutable and not aliasable.
|
|
MutBorrow,
|
|
}
|
|
|
|
/// Information describing the capture of an upvar. This is computed
|
|
/// during `typeck`, specifically by `regionck`.
|
|
#[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub enum UpvarCapture<'tcx> {
|
|
/// Upvar is captured by value. This is always true when the
|
|
/// closure is labeled `move`, but can also be true in other cases
|
|
/// depending on inference.
|
|
ByValue,
|
|
|
|
/// Upvar is captured by reference.
|
|
ByRef(UpvarBorrow<'tcx>),
|
|
}
|
|
|
|
#[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub struct UpvarBorrow<'tcx> {
|
|
/// The kind of borrow: by-ref upvars have access to shared
|
|
/// immutable borrows, which are not part of the normal language
|
|
/// syntax.
|
|
pub kind: BorrowKind,
|
|
|
|
/// Region of the resulting reference.
|
|
pub region: ty::Region<'tcx>,
|
|
}
|
|
|
|
pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
|
|
pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq)]
|
|
pub enum IntVarValue {
|
|
IntType(ast::IntTy),
|
|
UintType(ast::UintTy),
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq)]
|
|
pub struct FloatVarValue(pub ast::FloatTy);
|
|
|
|
impl ty::EarlyBoundRegion {
|
|
pub fn to_bound_region(&self) -> ty::BoundRegion {
|
|
ty::BoundRegion::BrNamed(self.def_id, self.name)
|
|
}
|
|
|
|
/// Does this early bound region have a name? Early bound regions normally
|
|
/// always have names except when using anonymous lifetimes (`'_`).
|
|
pub fn has_name(&self) -> bool {
|
|
self.name != kw::UnderscoreLifetime
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub enum GenericParamDefKind {
|
|
Lifetime,
|
|
Type {
|
|
has_default: bool,
|
|
object_lifetime_default: ObjectLifetimeDefault,
|
|
synthetic: Option<hir::SyntheticTyParamKind>,
|
|
},
|
|
Const,
|
|
}
|
|
|
|
impl GenericParamDefKind {
|
|
pub fn descr(&self) -> &'static str {
|
|
match self {
|
|
GenericParamDefKind::Lifetime => "lifetime",
|
|
GenericParamDefKind::Type { .. } => "type",
|
|
GenericParamDefKind::Const => "constant",
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub struct GenericParamDef {
|
|
pub name: Symbol,
|
|
pub def_id: DefId,
|
|
pub index: u32,
|
|
|
|
/// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
|
|
/// on generic parameter `'a`/`T`, asserts data behind the parameter
|
|
/// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
|
|
pub pure_wrt_drop: bool,
|
|
|
|
pub kind: GenericParamDefKind,
|
|
}
|
|
|
|
impl GenericParamDef {
|
|
pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
|
|
if let GenericParamDefKind::Lifetime = self.kind {
|
|
ty::EarlyBoundRegion { def_id: self.def_id, index: self.index, name: self.name }
|
|
} else {
|
|
bug!("cannot convert a non-lifetime parameter def to an early bound region")
|
|
}
|
|
}
|
|
|
|
pub fn to_bound_region(&self) -> ty::BoundRegion {
|
|
if let GenericParamDefKind::Lifetime = self.kind {
|
|
self.to_early_bound_region_data().to_bound_region()
|
|
} else {
|
|
bug!("cannot convert a non-lifetime parameter def to an early bound region")
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Default)]
|
|
pub struct GenericParamCount {
|
|
pub lifetimes: usize,
|
|
pub types: usize,
|
|
pub consts: usize,
|
|
}
|
|
|
|
/// Information about the formal type/lifetime parameters associated
|
|
/// with an item or method. Analogous to `hir::Generics`.
|
|
///
|
|
/// The ordering of parameters is the same as in `Subst` (excluding child generics):
|
|
/// `Self` (optionally), `Lifetime` params..., `Type` params...
|
|
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub struct Generics {
|
|
pub parent: Option<DefId>,
|
|
pub parent_count: usize,
|
|
pub params: Vec<GenericParamDef>,
|
|
|
|
/// Reverse map to the `index` field of each `GenericParamDef`.
|
|
#[stable_hasher(ignore)]
|
|
pub param_def_id_to_index: FxHashMap<DefId, u32>,
|
|
|
|
pub has_self: bool,
|
|
pub has_late_bound_regions: Option<Span>,
|
|
}
|
|
|
|
impl<'tcx> Generics {
|
|
pub fn count(&self) -> usize {
|
|
self.parent_count + self.params.len()
|
|
}
|
|
|
|
pub fn own_counts(&self) -> GenericParamCount {
|
|
// We could cache this as a property of `GenericParamCount`, but
|
|
// the aim is to refactor this away entirely eventually and the
|
|
// presence of this method will be a constant reminder.
|
|
let mut own_counts: GenericParamCount = Default::default();
|
|
|
|
for param in &self.params {
|
|
match param.kind {
|
|
GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
|
|
GenericParamDefKind::Type { .. } => own_counts.types += 1,
|
|
GenericParamDefKind::Const => own_counts.consts += 1,
|
|
};
|
|
}
|
|
|
|
own_counts
|
|
}
|
|
|
|
pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
|
|
if self.own_requires_monomorphization() {
|
|
return true;
|
|
}
|
|
|
|
if let Some(parent_def_id) = self.parent {
|
|
let parent = tcx.generics_of(parent_def_id);
|
|
parent.requires_monomorphization(tcx)
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
pub fn own_requires_monomorphization(&self) -> bool {
|
|
for param in &self.params {
|
|
match param.kind {
|
|
GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => return true,
|
|
GenericParamDefKind::Lifetime => {}
|
|
}
|
|
}
|
|
false
|
|
}
|
|
|
|
pub fn param_at(&'tcx self, param_index: usize, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
|
|
if let Some(index) = param_index.checked_sub(self.parent_count) {
|
|
&self.params[index]
|
|
} else {
|
|
tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
|
|
.param_at(param_index, tcx)
|
|
}
|
|
}
|
|
|
|
pub fn region_param(
|
|
&'tcx self,
|
|
param: &EarlyBoundRegion,
|
|
tcx: TyCtxt<'tcx>,
|
|
) -> &'tcx GenericParamDef {
|
|
let param = self.param_at(param.index as usize, tcx);
|
|
match param.kind {
|
|
GenericParamDefKind::Lifetime => param,
|
|
_ => bug!("expected lifetime parameter, but found another generic parameter"),
|
|
}
|
|
}
|
|
|
|
/// Returns the `GenericParamDef` associated with this `ParamTy`.
|
|
pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
|
|
let param = self.param_at(param.index as usize, tcx);
|
|
match param.kind {
|
|
GenericParamDefKind::Type { .. } => param,
|
|
_ => bug!("expected type parameter, but found another generic parameter"),
|
|
}
|
|
}
|
|
|
|
/// Returns the `ConstParameterDef` associated with this `ParamConst`.
|
|
pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
|
|
let param = self.param_at(param.index as usize, tcx);
|
|
match param.kind {
|
|
GenericParamDefKind::Const => param,
|
|
_ => bug!("expected const parameter, but found another generic parameter"),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Bounds on generics.
|
|
#[derive(Copy, Clone, Default, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub struct GenericPredicates<'tcx> {
|
|
pub parent: Option<DefId>,
|
|
pub predicates: &'tcx [(Predicate<'tcx>, Span)],
|
|
}
|
|
|
|
impl<'tcx> GenericPredicates<'tcx> {
|
|
pub fn instantiate(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
substs: SubstsRef<'tcx>,
|
|
) -> InstantiatedPredicates<'tcx> {
|
|
let mut instantiated = InstantiatedPredicates::empty();
|
|
self.instantiate_into(tcx, &mut instantiated, substs);
|
|
instantiated
|
|
}
|
|
|
|
pub fn instantiate_own(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
substs: SubstsRef<'tcx>,
|
|
) -> InstantiatedPredicates<'tcx> {
|
|
InstantiatedPredicates {
|
|
predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
|
|
spans: self.predicates.iter().map(|(_, sp)| *sp).collect(),
|
|
}
|
|
}
|
|
|
|
fn instantiate_into(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
instantiated: &mut InstantiatedPredicates<'tcx>,
|
|
substs: SubstsRef<'tcx>,
|
|
) {
|
|
if let Some(def_id) = self.parent {
|
|
tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
|
|
}
|
|
instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)));
|
|
instantiated.spans.extend(self.predicates.iter().map(|(_, sp)| *sp));
|
|
}
|
|
|
|
pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
|
|
let mut instantiated = InstantiatedPredicates::empty();
|
|
self.instantiate_identity_into(tcx, &mut instantiated);
|
|
instantiated
|
|
}
|
|
|
|
fn instantiate_identity_into(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
instantiated: &mut InstantiatedPredicates<'tcx>,
|
|
) {
|
|
if let Some(def_id) = self.parent {
|
|
tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
|
|
}
|
|
instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p));
|
|
instantiated.spans.extend(self.predicates.iter().map(|(_, s)| s));
|
|
}
|
|
|
|
pub fn instantiate_supertrait(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
poly_trait_ref: &ty::PolyTraitRef<'tcx>,
|
|
) -> InstantiatedPredicates<'tcx> {
|
|
assert_eq!(self.parent, None);
|
|
InstantiatedPredicates {
|
|
predicates: self
|
|
.predicates
|
|
.iter()
|
|
.map(|(pred, _)| pred.subst_supertrait(tcx, poly_trait_ref))
|
|
.collect(),
|
|
spans: self.predicates.iter().map(|(_, sp)| *sp).collect(),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
#[derive(HashStable, TypeFoldable)]
|
|
pub enum Predicate<'tcx> {
|
|
/// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
|
|
/// the `Self` type of the trait reference and `A`, `B`, and `C`
|
|
/// would be the type parameters.
|
|
///
|
|
/// A trait predicate will have `Constness::Const` if it originates
|
|
/// from a bound on a `const fn` without the `?const` opt-out (e.g.,
|
|
/// `const fn foobar<Foo: Bar>() {}`).
|
|
Trait(PolyTraitPredicate<'tcx>, Constness),
|
|
|
|
/// `where 'a: 'b`
|
|
RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
|
|
|
|
/// `where T: 'a`
|
|
TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
|
|
|
|
/// `where <T as TraitRef>::Name == X`, approximately.
|
|
/// See the `ProjectionPredicate` struct for details.
|
|
Projection(PolyProjectionPredicate<'tcx>),
|
|
|
|
/// No syntax: `T` well-formed.
|
|
WellFormed(Ty<'tcx>),
|
|
|
|
/// Trait must be object-safe.
|
|
ObjectSafe(DefId),
|
|
|
|
/// No direct syntax. May be thought of as `where T: FnFoo<...>`
|
|
/// for some substitutions `...` and `T` being a closure type.
|
|
/// Satisfied (or refuted) once we know the closure's kind.
|
|
ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
|
|
|
|
/// `T1 <: T2`
|
|
Subtype(PolySubtypePredicate<'tcx>),
|
|
|
|
/// Constant initializer must evaluate successfully.
|
|
ConstEvaluatable(DefId, SubstsRef<'tcx>),
|
|
}
|
|
|
|
/// The crate outlives map is computed during typeck and contains the
|
|
/// outlives of every item in the local crate. You should not use it
|
|
/// directly, because to do so will make your pass dependent on the
|
|
/// HIR of every item in the local crate. Instead, use
|
|
/// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
|
|
/// item.
|
|
#[derive(HashStable)]
|
|
pub struct CratePredicatesMap<'tcx> {
|
|
/// For each struct with outlive bounds, maps to a vector of the
|
|
/// predicate of its outlive bounds. If an item has no outlives
|
|
/// bounds, it will have no entry.
|
|
pub predicates: FxHashMap<DefId, &'tcx [(ty::Predicate<'tcx>, Span)]>,
|
|
}
|
|
|
|
impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
|
|
fn as_ref(&self) -> &Predicate<'tcx> {
|
|
self
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Predicate<'tcx> {
|
|
/// Performs a substitution suitable for going from a
|
|
/// poly-trait-ref to supertraits that must hold if that
|
|
/// poly-trait-ref holds. This is slightly different from a normal
|
|
/// substitution in terms of what happens with bound regions. See
|
|
/// lengthy comment below for details.
|
|
pub fn subst_supertrait(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
trait_ref: &ty::PolyTraitRef<'tcx>,
|
|
) -> ty::Predicate<'tcx> {
|
|
// The interaction between HRTB and supertraits is not entirely
|
|
// obvious. Let me walk you (and myself) through an example.
|
|
//
|
|
// Let's start with an easy case. Consider two traits:
|
|
//
|
|
// trait Foo<'a>: Bar<'a,'a> { }
|
|
// trait Bar<'b,'c> { }
|
|
//
|
|
// Now, if we have a trait reference `for<'x> T: Foo<'x>`, then
|
|
// we can deduce that `for<'x> T: Bar<'x,'x>`. Basically, if we
|
|
// knew that `Foo<'x>` (for any 'x) then we also know that
|
|
// `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
|
|
// normal substitution.
|
|
//
|
|
// In terms of why this is sound, the idea is that whenever there
|
|
// is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
|
|
// holds. So if there is an impl of `T:Foo<'a>` that applies to
|
|
// all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
|
|
// `'a`.
|
|
//
|
|
// Another example to be careful of is this:
|
|
//
|
|
// trait Foo1<'a>: for<'b> Bar1<'a,'b> { }
|
|
// trait Bar1<'b,'c> { }
|
|
//
|
|
// Here, if we have `for<'x> T: Foo1<'x>`, then what do we know?
|
|
// The answer is that we know `for<'x,'b> T: Bar1<'x,'b>`. The
|
|
// reason is similar to the previous example: any impl of
|
|
// `T:Foo1<'x>` must show that `for<'b> T: Bar1<'x, 'b>`. So
|
|
// basically we would want to collapse the bound lifetimes from
|
|
// the input (`trait_ref`) and the supertraits.
|
|
//
|
|
// To achieve this in practice is fairly straightforward. Let's
|
|
// consider the more complicated scenario:
|
|
//
|
|
// - We start out with `for<'x> T: Foo1<'x>`. In this case, `'x`
|
|
// has a De Bruijn index of 1. We want to produce `for<'x,'b> T: Bar1<'x,'b>`,
|
|
// where both `'x` and `'b` would have a DB index of 1.
|
|
// The substitution from the input trait-ref is therefore going to be
|
|
// `'a => 'x` (where `'x` has a DB index of 1).
|
|
// - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
|
|
// early-bound parameter and `'b' is a late-bound parameter with a
|
|
// DB index of 1.
|
|
// - If we replace `'a` with `'x` from the input, it too will have
|
|
// a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
|
|
// just as we wanted.
|
|
//
|
|
// There is only one catch. If we just apply the substitution `'a
|
|
// => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
|
|
// adjust the DB index because we substituting into a binder (it
|
|
// tries to be so smart...) resulting in `for<'x> for<'b>
|
|
// Bar1<'x,'b>` (we have no syntax for this, so use your
|
|
// imagination). Basically the 'x will have DB index of 2 and 'b
|
|
// will have DB index of 1. Not quite what we want. So we apply
|
|
// the substitution to the *contents* of the trait reference,
|
|
// rather than the trait reference itself (put another way, the
|
|
// substitution code expects equal binding levels in the values
|
|
// from the substitution and the value being substituted into, and
|
|
// this trick achieves that).
|
|
|
|
let substs = &trait_ref.skip_binder().substs;
|
|
match *self {
|
|
Predicate::Trait(ref binder, constness) => {
|
|
Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs)), constness)
|
|
}
|
|
Predicate::Subtype(ref binder) => {
|
|
Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs)))
|
|
}
|
|
Predicate::RegionOutlives(ref binder) => {
|
|
Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs)))
|
|
}
|
|
Predicate::TypeOutlives(ref binder) => {
|
|
Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs)))
|
|
}
|
|
Predicate::Projection(ref binder) => {
|
|
Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs)))
|
|
}
|
|
Predicate::WellFormed(data) => Predicate::WellFormed(data.subst(tcx, substs)),
|
|
Predicate::ObjectSafe(trait_def_id) => Predicate::ObjectSafe(trait_def_id),
|
|
Predicate::ClosureKind(closure_def_id, closure_substs, kind) => {
|
|
Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind)
|
|
}
|
|
Predicate::ConstEvaluatable(def_id, const_substs) => {
|
|
Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
#[derive(HashStable, TypeFoldable)]
|
|
pub struct TraitPredicate<'tcx> {
|
|
pub trait_ref: TraitRef<'tcx>,
|
|
}
|
|
|
|
pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
|
|
|
|
impl<'tcx> TraitPredicate<'tcx> {
|
|
pub fn def_id(&self) -> DefId {
|
|
self.trait_ref.def_id
|
|
}
|
|
|
|
pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> + 'a {
|
|
self.trait_ref.input_types()
|
|
}
|
|
|
|
pub fn self_ty(&self) -> Ty<'tcx> {
|
|
self.trait_ref.self_ty()
|
|
}
|
|
}
|
|
|
|
impl<'tcx> PolyTraitPredicate<'tcx> {
|
|
pub fn def_id(&self) -> DefId {
|
|
// Ok to skip binder since trait `DefId` does not care about regions.
|
|
self.skip_binder().def_id()
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
#[derive(HashStable, TypeFoldable)]
|
|
pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
|
|
pub type PolyOutlivesPredicate<A, B> = ty::Binder<OutlivesPredicate<A, B>>;
|
|
pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
|
|
pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
|
|
pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
|
|
pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
#[derive(HashStable, TypeFoldable)]
|
|
pub struct SubtypePredicate<'tcx> {
|
|
pub a_is_expected: bool,
|
|
pub a: Ty<'tcx>,
|
|
pub b: Ty<'tcx>,
|
|
}
|
|
pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
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|
|
|
/// This kind of predicate has no *direct* correspondent in the
|
|
/// syntax, but it roughly corresponds to the syntactic forms:
|
|
///
|
|
/// 1. `T: TraitRef<..., Item = Type>`
|
|
/// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
|
|
///
|
|
/// In particular, form #1 is "desugared" to the combination of a
|
|
/// normal trait predicate (`T: TraitRef<...>`) and one of these
|
|
/// predicates. Form #2 is a broader form in that it also permits
|
|
/// equality between arbitrary types. Processing an instance of
|
|
/// Form #2 eventually yields one of these `ProjectionPredicate`
|
|
/// instances to normalize the LHS.
|
|
#[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
#[derive(HashStable, TypeFoldable)]
|
|
pub struct ProjectionPredicate<'tcx> {
|
|
pub projection_ty: ProjectionTy<'tcx>,
|
|
pub ty: Ty<'tcx>,
|
|
}
|
|
|
|
pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
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|
|
|
impl<'tcx> PolyProjectionPredicate<'tcx> {
|
|
/// Returns the `DefId` of the associated item being projected.
|
|
pub fn item_def_id(&self) -> DefId {
|
|
self.skip_binder().projection_ty.item_def_id
|
|
}
|
|
|
|
#[inline]
|
|
pub fn to_poly_trait_ref(&self, tcx: TyCtxt<'tcx>) -> PolyTraitRef<'tcx> {
|
|
// Note: unlike with `TraitRef::to_poly_trait_ref()`,
|
|
// `self.0.trait_ref` is permitted to have escaping regions.
|
|
// This is because here `self` has a `Binder` and so does our
|
|
// return value, so we are preserving the number of binding
|
|
// levels.
|
|
self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
|
|
}
|
|
|
|
pub fn ty(&self) -> Binder<Ty<'tcx>> {
|
|
self.map_bound(|predicate| predicate.ty)
|
|
}
|
|
|
|
/// The `DefId` of the `TraitItem` for the associated type.
|
|
///
|
|
/// Note that this is not the `DefId` of the `TraitRef` containing this
|
|
/// associated type, which is in `tcx.associated_item(projection_def_id()).container`.
|
|
pub fn projection_def_id(&self) -> DefId {
|
|
// Ok to skip binder since trait `DefId` does not care about regions.
|
|
self.skip_binder().projection_ty.item_def_id
|
|
}
|
|
}
|
|
|
|
pub trait ToPolyTraitRef<'tcx> {
|
|
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
|
|
}
|
|
|
|
impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
|
|
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
|
|
ty::Binder::dummy(*self)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
|
|
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
|
|
self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
|
|
}
|
|
}
|
|
|
|
pub trait ToPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx>;
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<TraitRef<'tcx>> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
ty::Predicate::Trait(
|
|
ty::Binder::dummy(ty::TraitPredicate { trait_ref: self.value }),
|
|
self.constness,
|
|
)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<&TraitRef<'tcx>> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
ty::Predicate::Trait(
|
|
ty::Binder::dummy(ty::TraitPredicate { trait_ref: *self.value }),
|
|
self.constness,
|
|
)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<PolyTraitRef<'tcx>> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
ty::Predicate::Trait(self.value.to_poly_trait_predicate(), self.constness)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<&PolyTraitRef<'tcx>> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
ty::Predicate::Trait(self.value.to_poly_trait_predicate(), self.constness)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
Predicate::RegionOutlives(*self)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
Predicate::TypeOutlives(*self)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
Predicate::Projection(*self)
|
|
}
|
|
}
|
|
|
|
// A custom iterator used by `Predicate::walk_tys`.
|
|
enum WalkTysIter<'tcx, I, J, K>
|
|
where
|
|
I: Iterator<Item = Ty<'tcx>>,
|
|
J: Iterator<Item = Ty<'tcx>>,
|
|
K: Iterator<Item = Ty<'tcx>>,
|
|
{
|
|
None,
|
|
One(Ty<'tcx>),
|
|
Two(Ty<'tcx>, Ty<'tcx>),
|
|
Types(I),
|
|
InputTypes(J),
|
|
ProjectionTypes(K),
|
|
}
|
|
|
|
impl<'tcx, I, J, K> Iterator for WalkTysIter<'tcx, I, J, K>
|
|
where
|
|
I: Iterator<Item = Ty<'tcx>>,
|
|
J: Iterator<Item = Ty<'tcx>>,
|
|
K: Iterator<Item = Ty<'tcx>>,
|
|
{
|
|
type Item = Ty<'tcx>;
|
|
|
|
fn next(&mut self) -> Option<Ty<'tcx>> {
|
|
match *self {
|
|
WalkTysIter::None => None,
|
|
WalkTysIter::One(item) => {
|
|
*self = WalkTysIter::None;
|
|
Some(item)
|
|
}
|
|
WalkTysIter::Two(item1, item2) => {
|
|
*self = WalkTysIter::One(item2);
|
|
Some(item1)
|
|
}
|
|
WalkTysIter::Types(ref mut iter) => iter.next(),
|
|
WalkTysIter::InputTypes(ref mut iter) => iter.next(),
|
|
WalkTysIter::ProjectionTypes(ref mut iter) => iter.next(),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Predicate<'tcx> {
|
|
/// Iterates over the types in this predicate. Note that in all
|
|
/// cases this is skipping over a binder, so late-bound regions
|
|
/// with depth 0 are bound by the predicate.
|
|
pub fn walk_tys(&'a self) -> impl Iterator<Item = Ty<'tcx>> + 'a {
|
|
match *self {
|
|
ty::Predicate::Trait(ref data, _) => {
|
|
WalkTysIter::InputTypes(data.skip_binder().input_types())
|
|
}
|
|
ty::Predicate::Subtype(binder) => {
|
|
let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
|
|
WalkTysIter::Two(a, b)
|
|
}
|
|
ty::Predicate::TypeOutlives(binder) => WalkTysIter::One(binder.skip_binder().0),
|
|
ty::Predicate::RegionOutlives(..) => WalkTysIter::None,
|
|
ty::Predicate::Projection(ref data) => {
|
|
let inner = data.skip_binder();
|
|
WalkTysIter::ProjectionTypes(
|
|
inner.projection_ty.substs.types().chain(Some(inner.ty)),
|
|
)
|
|
}
|
|
ty::Predicate::WellFormed(data) => WalkTysIter::One(data),
|
|
ty::Predicate::ObjectSafe(_trait_def_id) => WalkTysIter::None,
|
|
ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
|
|
WalkTysIter::Types(closure_substs.types())
|
|
}
|
|
ty::Predicate::ConstEvaluatable(_, substs) => WalkTysIter::Types(substs.types()),
|
|
}
|
|
}
|
|
|
|
pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
|
|
match *self {
|
|
Predicate::Trait(ref t, _) => Some(t.to_poly_trait_ref()),
|
|
Predicate::Projection(..)
|
|
| Predicate::Subtype(..)
|
|
| Predicate::RegionOutlives(..)
|
|
| Predicate::WellFormed(..)
|
|
| Predicate::ObjectSafe(..)
|
|
| Predicate::ClosureKind(..)
|
|
| Predicate::TypeOutlives(..)
|
|
| Predicate::ConstEvaluatable(..) => None,
|
|
}
|
|
}
|
|
|
|
pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
|
|
match *self {
|
|
Predicate::TypeOutlives(data) => Some(data),
|
|
Predicate::Trait(..)
|
|
| Predicate::Projection(..)
|
|
| Predicate::Subtype(..)
|
|
| Predicate::RegionOutlives(..)
|
|
| Predicate::WellFormed(..)
|
|
| Predicate::ObjectSafe(..)
|
|
| Predicate::ClosureKind(..)
|
|
| Predicate::ConstEvaluatable(..) => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Represents the bounds declared on a particular set of type
|
|
/// parameters. Should eventually be generalized into a flag list of
|
|
/// where-clauses. You can obtain a `InstantiatedPredicates` list from a
|
|
/// `GenericPredicates` by using the `instantiate` method. Note that this method
|
|
/// reflects an important semantic invariant of `InstantiatedPredicates`: while
|
|
/// the `GenericPredicates` are expressed in terms of the bound type
|
|
/// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
|
|
/// represented a set of bounds for some particular instantiation,
|
|
/// meaning that the generic parameters have been substituted with
|
|
/// their values.
|
|
///
|
|
/// Example:
|
|
///
|
|
/// struct Foo<T, U: Bar<T>> { ... }
|
|
///
|
|
/// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
|
|
/// `[[], [U:Bar<T>]]`. Now if there were some particular reference
|
|
/// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
|
|
/// [usize:Bar<isize>]]`.
|
|
#[derive(Clone, Debug, TypeFoldable)]
|
|
pub struct InstantiatedPredicates<'tcx> {
|
|
pub predicates: Vec<Predicate<'tcx>>,
|
|
pub spans: Vec<Span>,
|
|
}
|
|
|
|
impl<'tcx> InstantiatedPredicates<'tcx> {
|
|
pub fn empty() -> InstantiatedPredicates<'tcx> {
|
|
InstantiatedPredicates { predicates: vec![], spans: vec![] }
|
|
}
|
|
|
|
pub fn is_empty(&self) -> bool {
|
|
self.predicates.is_empty()
|
|
}
|
|
}
|
|
|
|
rustc_index::newtype_index! {
|
|
/// "Universes" are used during type- and trait-checking in the
|
|
/// presence of `for<..>` binders to control what sets of names are
|
|
/// visible. Universes are arranged into a tree: the root universe
|
|
/// contains names that are always visible. Each child then adds a new
|
|
/// set of names that are visible, in addition to those of its parent.
|
|
/// We say that the child universe "extends" the parent universe with
|
|
/// new names.
|
|
///
|
|
/// To make this more concrete, consider this program:
|
|
///
|
|
/// ```
|
|
/// struct Foo { }
|
|
/// fn bar<T>(x: T) {
|
|
/// let y: for<'a> fn(&'a u8, Foo) = ...;
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// The struct name `Foo` is in the root universe U0. But the type
|
|
/// parameter `T`, introduced on `bar`, is in an extended universe U1
|
|
/// -- i.e., within `bar`, we can name both `T` and `Foo`, but outside
|
|
/// of `bar`, we cannot name `T`. Then, within the type of `y`, the
|
|
/// region `'a` is in a universe U2 that extends U1, because we can
|
|
/// name it inside the fn type but not outside.
|
|
///
|
|
/// Universes are used to do type- and trait-checking around these
|
|
/// "forall" binders (also called **universal quantification**). The
|
|
/// idea is that when, in the body of `bar`, we refer to `T` as a
|
|
/// type, we aren't referring to any type in particular, but rather a
|
|
/// kind of "fresh" type that is distinct from all other types we have
|
|
/// actually declared. This is called a **placeholder** type, and we
|
|
/// use universes to talk about this. In other words, a type name in
|
|
/// universe 0 always corresponds to some "ground" type that the user
|
|
/// declared, but a type name in a non-zero universe is a placeholder
|
|
/// type -- an idealized representative of "types in general" that we
|
|
/// use for checking generic functions.
|
|
pub struct UniverseIndex {
|
|
derive [HashStable]
|
|
DEBUG_FORMAT = "U{}",
|
|
}
|
|
}
|
|
|
|
impl UniverseIndex {
|
|
pub const ROOT: UniverseIndex = UniverseIndex::from_u32(0);
|
|
|
|
/// Returns the "next" universe index in order -- this new index
|
|
/// is considered to extend all previous universes. This
|
|
/// corresponds to entering a `forall` quantifier. So, for
|
|
/// example, suppose we have this type in universe `U`:
|
|
///
|
|
/// ```
|
|
/// for<'a> fn(&'a u32)
|
|
/// ```
|
|
///
|
|
/// Once we "enter" into this `for<'a>` quantifier, we are in a
|
|
/// new universe that extends `U` -- in this new universe, we can
|
|
/// name the region `'a`, but that region was not nameable from
|
|
/// `U` because it was not in scope there.
|
|
pub fn next_universe(self) -> UniverseIndex {
|
|
UniverseIndex::from_u32(self.private.checked_add(1).unwrap())
|
|
}
|
|
|
|
/// Returns `true` if `self` can name a name from `other` -- in other words,
|
|
/// if the set of names in `self` is a superset of those in
|
|
/// `other` (`self >= other`).
|
|
pub fn can_name(self, other: UniverseIndex) -> bool {
|
|
self.private >= other.private
|
|
}
|
|
|
|
/// Returns `true` if `self` cannot name some names from `other` -- in other
|
|
/// words, if the set of names in `self` is a strict subset of
|
|
/// those in `other` (`self < other`).
|
|
pub fn cannot_name(self, other: UniverseIndex) -> bool {
|
|
self.private < other.private
|
|
}
|
|
}
|
|
|
|
/// The "placeholder index" fully defines a placeholder region.
|
|
/// Placeholder regions are identified by both a **universe** as well
|
|
/// as a "bound-region" within that universe. The `bound_region` is
|
|
/// basically a name -- distinct bound regions within the same
|
|
/// universe are just two regions with an unknown relationship to one
|
|
/// another.
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
|
|
pub struct Placeholder<T> {
|
|
pub universe: UniverseIndex,
|
|
pub name: T,
|
|
}
|
|
|
|
impl<'a, T> HashStable<StableHashingContext<'a>> for Placeholder<T>
|
|
where
|
|
T: HashStable<StableHashingContext<'a>>,
|
|
{
|
|
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
|
|
self.universe.hash_stable(hcx, hasher);
|
|
self.name.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
pub type PlaceholderRegion = Placeholder<BoundRegion>;
|
|
|
|
pub type PlaceholderType = Placeholder<BoundVar>;
|
|
|
|
pub type PlaceholderConst = Placeholder<BoundVar>;
|
|
|
|
/// When type checking, we use the `ParamEnv` to track
|
|
/// details about the set of where-clauses that are in scope at this
|
|
/// particular point.
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TypeFoldable)]
|
|
pub struct ParamEnv<'tcx> {
|
|
/// `Obligation`s that the caller must satisfy. This is basically
|
|
/// the set of bounds on the in-scope type parameters, translated
|
|
/// into `Obligation`s, and elaborated and normalized.
|
|
pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
|
|
|
|
/// Typically, this is `Reveal::UserFacing`, but during codegen we
|
|
/// want `Reveal::All` -- note that this is always paired with an
|
|
/// empty environment. To get that, use `ParamEnv::reveal()`.
|
|
pub reveal: traits::Reveal,
|
|
|
|
/// If this `ParamEnv` comes from a call to `tcx.param_env(def_id)`,
|
|
/// register that `def_id` (useful for transitioning to the chalk trait
|
|
/// solver).
|
|
pub def_id: Option<DefId>,
|
|
}
|
|
|
|
impl<'tcx> ParamEnv<'tcx> {
|
|
/// Construct a trait environment suitable for contexts where
|
|
/// there are no where-clauses in scope. Hidden types (like `impl
|
|
/// Trait`) are left hidden, so this is suitable for ordinary
|
|
/// type-checking.
|
|
#[inline]
|
|
pub fn empty() -> Self {
|
|
Self::new(List::empty(), Reveal::UserFacing, None)
|
|
}
|
|
|
|
/// Construct a trait environment with no where-clauses in scope
|
|
/// where the values of all `impl Trait` and other hidden types
|
|
/// are revealed. This is suitable for monomorphized, post-typeck
|
|
/// environments like codegen or doing optimizations.
|
|
///
|
|
/// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
|
|
/// or invoke `param_env.with_reveal_all()`.
|
|
#[inline]
|
|
pub fn reveal_all() -> Self {
|
|
Self::new(List::empty(), Reveal::All, None)
|
|
}
|
|
|
|
/// Construct a trait environment with the given set of predicates.
|
|
#[inline]
|
|
pub fn new(
|
|
caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
|
|
reveal: Reveal,
|
|
def_id: Option<DefId>,
|
|
) -> Self {
|
|
ty::ParamEnv { caller_bounds, reveal, def_id }
|
|
}
|
|
|
|
/// Returns a new parameter environment with the same clauses, but
|
|
/// which "reveals" the true results of projections in all cases
|
|
/// (even for associated types that are specializable). This is
|
|
/// the desired behavior during codegen and certain other special
|
|
/// contexts; normally though we want to use `Reveal::UserFacing`,
|
|
/// which is the default.
|
|
pub fn with_reveal_all(self) -> Self {
|
|
ty::ParamEnv { reveal: Reveal::All, ..self }
|
|
}
|
|
|
|
/// Returns this same environment but with no caller bounds.
|
|
pub fn without_caller_bounds(self) -> Self {
|
|
ty::ParamEnv { caller_bounds: List::empty(), ..self }
|
|
}
|
|
|
|
/// Creates a suitable environment in which to perform trait
|
|
/// queries on the given value. When type-checking, this is simply
|
|
/// the pair of the environment plus value. But when reveal is set to
|
|
/// All, then if `value` does not reference any type parameters, we will
|
|
/// pair it with the empty environment. This improves caching and is generally
|
|
/// invisible.
|
|
///
|
|
/// N.B., we preserve the environment when type-checking because it
|
|
/// is possible for the user to have wacky where-clauses like
|
|
/// `where Box<u32>: Copy`, which are clearly never
|
|
/// satisfiable. We generally want to behave as if they were true,
|
|
/// although the surrounding function is never reachable.
|
|
pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
|
|
match self.reveal {
|
|
Reveal::UserFacing => ParamEnvAnd { param_env: self, value },
|
|
|
|
Reveal::All => {
|
|
if value.is_global() {
|
|
ParamEnvAnd { param_env: self.without_caller_bounds(), value }
|
|
} else {
|
|
ParamEnvAnd { param_env: self, value }
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
|
|
pub struct ConstnessAnd<T> {
|
|
pub constness: Constness,
|
|
pub value: T,
|
|
}
|
|
|
|
// FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate()` to ensure that
|
|
// the constness of trait bounds is being propagated correctly.
|
|
pub trait WithConstness: Sized {
|
|
#[inline]
|
|
fn with_constness(self, constness: Constness) -> ConstnessAnd<Self> {
|
|
ConstnessAnd { constness, value: self }
|
|
}
|
|
|
|
#[inline]
|
|
fn with_const(self) -> ConstnessAnd<Self> {
|
|
self.with_constness(Constness::Const)
|
|
}
|
|
|
|
#[inline]
|
|
fn without_const(self) -> ConstnessAnd<Self> {
|
|
self.with_constness(Constness::NotConst)
|
|
}
|
|
}
|
|
|
|
impl<T> WithConstness for T {}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
|
|
pub struct ParamEnvAnd<'tcx, T> {
|
|
pub param_env: ParamEnv<'tcx>,
|
|
pub value: T,
|
|
}
|
|
|
|
impl<'tcx, T> ParamEnvAnd<'tcx, T> {
|
|
pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
|
|
(self.param_env, self.value)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'tcx, T>
|
|
where
|
|
T: HashStable<StableHashingContext<'a>>,
|
|
{
|
|
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
|
|
let ParamEnvAnd { ref param_env, ref value } = *self;
|
|
|
|
param_env.hash_stable(hcx, hasher);
|
|
value.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, HashStable)]
|
|
pub struct Destructor {
|
|
/// The `DefId` of the destructor method
|
|
pub did: DefId,
|
|
}
|
|
|
|
bitflags! {
|
|
#[derive(HashStable)]
|
|
pub struct AdtFlags: u32 {
|
|
const NO_ADT_FLAGS = 0;
|
|
/// Indicates whether the ADT is an enum.
|
|
const IS_ENUM = 1 << 0;
|
|
/// Indicates whether the ADT is a union.
|
|
const IS_UNION = 1 << 1;
|
|
/// Indicates whether the ADT is a struct.
|
|
const IS_STRUCT = 1 << 2;
|
|
/// Indicates whether the ADT is a struct and has a constructor.
|
|
const HAS_CTOR = 1 << 3;
|
|
/// Indicates whether the type is `PhantomData`.
|
|
const IS_PHANTOM_DATA = 1 << 4;
|
|
/// Indicates whether the type has a `#[fundamental]` attribute.
|
|
const IS_FUNDAMENTAL = 1 << 5;
|
|
/// Indicates whether the type is `Box`.
|
|
const IS_BOX = 1 << 6;
|
|
/// Indicates whether the type is `ManuallyDrop`.
|
|
const IS_MANUALLY_DROP = 1 << 7;
|
|
// FIXME(matthewjasper) replace these with diagnostic items
|
|
/// Indicates whether the type is an `Arc`.
|
|
const IS_ARC = 1 << 8;
|
|
/// Indicates whether the type is an `Rc`.
|
|
const IS_RC = 1 << 9;
|
|
/// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
|
|
/// (i.e., this flag is never set unless this ADT is an enum).
|
|
const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 10;
|
|
}
|
|
}
|
|
|
|
bitflags! {
|
|
#[derive(HashStable)]
|
|
pub struct VariantFlags: u32 {
|
|
const NO_VARIANT_FLAGS = 0;
|
|
/// Indicates whether the field list of this variant is `#[non_exhaustive]`.
|
|
const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
|
|
}
|
|
}
|
|
|
|
/// Definition of a variant -- a struct's fields or a enum variant.
|
|
#[derive(Debug, HashStable)]
|
|
pub struct VariantDef {
|
|
/// `DefId` that identifies the variant itself.
|
|
/// If this variant belongs to a struct or union, then this is a copy of its `DefId`.
|
|
pub def_id: DefId,
|
|
/// `DefId` that identifies the variant's constructor.
|
|
/// If this variant is a struct variant, then this is `None`.
|
|
pub ctor_def_id: Option<DefId>,
|
|
/// Variant or struct name.
|
|
#[stable_hasher(project(name))]
|
|
pub ident: Ident,
|
|
/// Discriminant of this variant.
|
|
pub discr: VariantDiscr,
|
|
/// Fields of this variant.
|
|
pub fields: Vec<FieldDef>,
|
|
/// Type of constructor of variant.
|
|
pub ctor_kind: CtorKind,
|
|
/// Flags of the variant (e.g. is field list non-exhaustive)?
|
|
flags: VariantFlags,
|
|
/// Variant is obtained as part of recovering from a syntactic error.
|
|
/// May be incomplete or bogus.
|
|
pub recovered: bool,
|
|
}
|
|
|
|
impl<'tcx> VariantDef {
|
|
/// Creates a new `VariantDef`.
|
|
///
|
|
/// `variant_did` is the `DefId` that identifies the enum variant (if this `VariantDef`
|
|
/// represents an enum variant).
|
|
///
|
|
/// `ctor_did` is the `DefId` that identifies the constructor of unit or
|
|
/// tuple-variants/structs. If this is a `struct`-variant then this should be `None`.
|
|
///
|
|
/// `parent_did` is the `DefId` of the `AdtDef` representing the enum or struct that
|
|
/// owns this variant. It is used for checking if a struct has `#[non_exhaustive]` w/out having
|
|
/// to go through the redirect of checking the ctor's attributes - but compiling a small crate
|
|
/// requires loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
|
|
/// built-in trait), and we do not want to load attributes twice.
|
|
///
|
|
/// If someone speeds up attribute loading to not be a performance concern, they can
|
|
/// remove this hack and use the constructor `DefId` everywhere.
|
|
pub fn new(
|
|
tcx: TyCtxt<'tcx>,
|
|
ident: Ident,
|
|
variant_did: Option<DefId>,
|
|
ctor_def_id: Option<DefId>,
|
|
discr: VariantDiscr,
|
|
fields: Vec<FieldDef>,
|
|
ctor_kind: CtorKind,
|
|
adt_kind: AdtKind,
|
|
parent_did: DefId,
|
|
recovered: bool,
|
|
) -> Self {
|
|
debug!(
|
|
"VariantDef::new(ident = {:?}, variant_did = {:?}, ctor_def_id = {:?}, discr = {:?},
|
|
fields = {:?}, ctor_kind = {:?}, adt_kind = {:?}, parent_did = {:?})",
|
|
ident, variant_did, ctor_def_id, discr, fields, ctor_kind, adt_kind, parent_did,
|
|
);
|
|
|
|
let mut flags = VariantFlags::NO_VARIANT_FLAGS;
|
|
if adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) {
|
|
debug!("found non-exhaustive field list for {:?}", parent_did);
|
|
flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
|
|
} else if let Some(variant_did) = variant_did {
|
|
if tcx.has_attr(variant_did, sym::non_exhaustive) {
|
|
debug!("found non-exhaustive field list for {:?}", variant_did);
|
|
flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
|
|
}
|
|
}
|
|
|
|
VariantDef {
|
|
def_id: variant_did.unwrap_or(parent_did),
|
|
ctor_def_id,
|
|
ident,
|
|
discr,
|
|
fields,
|
|
ctor_kind,
|
|
flags,
|
|
recovered,
|
|
}
|
|
}
|
|
|
|
/// Is this field list non-exhaustive?
|
|
#[inline]
|
|
pub fn is_field_list_non_exhaustive(&self) -> bool {
|
|
self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub enum VariantDiscr {
|
|
/// Explicit value for this variant, i.e., `X = 123`.
|
|
/// The `DefId` corresponds to the embedded constant.
|
|
Explicit(DefId),
|
|
|
|
/// The previous variant's discriminant plus one.
|
|
/// For efficiency reasons, the distance from the
|
|
/// last `Explicit` discriminant is being stored,
|
|
/// or `0` for the first variant, if it has none.
|
|
Relative(u32),
|
|
}
|
|
|
|
#[derive(Debug, HashStable)]
|
|
pub struct FieldDef {
|
|
pub did: DefId,
|
|
#[stable_hasher(project(name))]
|
|
pub ident: Ident,
|
|
pub vis: Visibility,
|
|
}
|
|
|
|
/// The definition of a user-defined type, e.g., a `struct`, `enum`, or `union`.
|
|
///
|
|
/// These are all interned (by `intern_adt_def`) into the `adt_defs` table.
|
|
///
|
|
/// The initialism *ADT* stands for an [*algebraic data type (ADT)*][adt].
|
|
/// This is slightly wrong because `union`s are not ADTs.
|
|
/// Moreover, Rust only allows recursive data types through indirection.
|
|
///
|
|
/// [adt]: https://en.wikipedia.org/wiki/Algebraic_data_type
|
|
pub struct AdtDef {
|
|
/// The `DefId` of the struct, enum or union item.
|
|
pub did: DefId,
|
|
/// Variants of the ADT. If this is a struct or union, then there will be a single variant.
|
|
pub variants: IndexVec<VariantIdx, VariantDef>,
|
|
/// Flags of the ADT (e.g., is this a struct? is this non-exhaustive?).
|
|
flags: AdtFlags,
|
|
/// Repr options provided by the user.
|
|
pub repr: ReprOptions,
|
|
}
|
|
|
|
impl PartialOrd for AdtDef {
|
|
fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
|
|
Some(self.cmp(&other))
|
|
}
|
|
}
|
|
|
|
/// There should be only one AdtDef for each `did`, therefore
|
|
/// it is fine to implement `Ord` only based on `did`.
|
|
impl Ord for AdtDef {
|
|
fn cmp(&self, other: &AdtDef) -> Ordering {
|
|
self.did.cmp(&other.did)
|
|
}
|
|
}
|
|
|
|
impl PartialEq for AdtDef {
|
|
// `AdtDef`s are always interned, and this is part of `TyS` equality.
|
|
#[inline]
|
|
fn eq(&self, other: &Self) -> bool {
|
|
ptr::eq(self, other)
|
|
}
|
|
}
|
|
|
|
impl Eq for AdtDef {}
|
|
|
|
impl Hash for AdtDef {
|
|
#[inline]
|
|
fn hash<H: Hasher>(&self, s: &mut H) {
|
|
(self as *const AdtDef).hash(s)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> rustc_serialize::UseSpecializedEncodable for &'tcx AdtDef {
|
|
fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
|
|
self.did.encode(s)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> rustc_serialize::UseSpecializedDecodable for &'tcx AdtDef {}
|
|
|
|
impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
|
|
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
|
|
thread_local! {
|
|
static CACHE: RefCell<FxHashMap<usize, Fingerprint>> = Default::default();
|
|
}
|
|
|
|
let hash: Fingerprint = CACHE.with(|cache| {
|
|
let addr = self as *const AdtDef as usize;
|
|
*cache.borrow_mut().entry(addr).or_insert_with(|| {
|
|
let ty::AdtDef { did, ref variants, ref flags, ref repr } = *self;
|
|
|
|
let mut hasher = StableHasher::new();
|
|
did.hash_stable(hcx, &mut hasher);
|
|
variants.hash_stable(hcx, &mut hasher);
|
|
flags.hash_stable(hcx, &mut hasher);
|
|
repr.hash_stable(hcx, &mut hasher);
|
|
|
|
hasher.finish()
|
|
})
|
|
});
|
|
|
|
hash.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
|
|
pub enum AdtKind {
|
|
Struct,
|
|
Union,
|
|
Enum,
|
|
}
|
|
|
|
impl Into<DataTypeKind> for AdtKind {
|
|
fn into(self) -> DataTypeKind {
|
|
match self {
|
|
AdtKind::Struct => DataTypeKind::Struct,
|
|
AdtKind::Union => DataTypeKind::Union,
|
|
AdtKind::Enum => DataTypeKind::Enum,
|
|
}
|
|
}
|
|
}
|
|
|
|
bitflags! {
|
|
#[derive(RustcEncodable, RustcDecodable, Default, HashStable)]
|
|
pub struct ReprFlags: u8 {
|
|
const IS_C = 1 << 0;
|
|
const IS_SIMD = 1 << 1;
|
|
const IS_TRANSPARENT = 1 << 2;
|
|
// Internal only for now. If true, don't reorder fields.
|
|
const IS_LINEAR = 1 << 3;
|
|
// If true, don't expose any niche to type's context.
|
|
const HIDE_NICHE = 1 << 4;
|
|
// Any of these flags being set prevent field reordering optimisation.
|
|
const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
|
|
ReprFlags::IS_SIMD.bits |
|
|
ReprFlags::IS_LINEAR.bits;
|
|
}
|
|
}
|
|
|
|
/// Represents the repr options provided by the user,
|
|
#[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default, HashStable)]
|
|
pub struct ReprOptions {
|
|
pub int: Option<attr::IntType>,
|
|
pub align: Option<Align>,
|
|
pub pack: Option<Align>,
|
|
pub flags: ReprFlags,
|
|
}
|
|
|
|
impl ReprOptions {
|
|
pub fn new(tcx: TyCtxt<'_>, did: DefId) -> ReprOptions {
|
|
let mut flags = ReprFlags::empty();
|
|
let mut size = None;
|
|
let mut max_align: Option<Align> = None;
|
|
let mut min_pack: Option<Align> = None;
|
|
for attr in tcx.get_attrs(did).iter() {
|
|
for r in attr::find_repr_attrs(&tcx.sess.parse_sess, attr) {
|
|
flags.insert(match r {
|
|
attr::ReprC => ReprFlags::IS_C,
|
|
attr::ReprPacked(pack) => {
|
|
let pack = Align::from_bytes(pack as u64).unwrap();
|
|
min_pack = Some(if let Some(min_pack) = min_pack {
|
|
min_pack.min(pack)
|
|
} else {
|
|
pack
|
|
});
|
|
ReprFlags::empty()
|
|
}
|
|
attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
|
|
attr::ReprNoNiche => ReprFlags::HIDE_NICHE,
|
|
attr::ReprSimd => ReprFlags::IS_SIMD,
|
|
attr::ReprInt(i) => {
|
|
size = Some(i);
|
|
ReprFlags::empty()
|
|
}
|
|
attr::ReprAlign(align) => {
|
|
max_align = max_align.max(Some(Align::from_bytes(align as u64).unwrap()));
|
|
ReprFlags::empty()
|
|
}
|
|
});
|
|
}
|
|
}
|
|
|
|
// This is here instead of layout because the choice must make it into metadata.
|
|
if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.def_path_str(did))) {
|
|
flags.insert(ReprFlags::IS_LINEAR);
|
|
}
|
|
ReprOptions { int: size, align: max_align, pack: min_pack, flags }
|
|
}
|
|
|
|
#[inline]
|
|
pub fn simd(&self) -> bool {
|
|
self.flags.contains(ReprFlags::IS_SIMD)
|
|
}
|
|
#[inline]
|
|
pub fn c(&self) -> bool {
|
|
self.flags.contains(ReprFlags::IS_C)
|
|
}
|
|
#[inline]
|
|
pub fn packed(&self) -> bool {
|
|
self.pack.is_some()
|
|
}
|
|
#[inline]
|
|
pub fn transparent(&self) -> bool {
|
|
self.flags.contains(ReprFlags::IS_TRANSPARENT)
|
|
}
|
|
#[inline]
|
|
pub fn linear(&self) -> bool {
|
|
self.flags.contains(ReprFlags::IS_LINEAR)
|
|
}
|
|
#[inline]
|
|
pub fn hide_niche(&self) -> bool {
|
|
self.flags.contains(ReprFlags::HIDE_NICHE)
|
|
}
|
|
|
|
pub fn discr_type(&self) -> attr::IntType {
|
|
self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
|
|
}
|
|
|
|
/// Returns `true` if this `#[repr()]` should inhabit "smart enum
|
|
/// layout" optimizations, such as representing `Foo<&T>` as a
|
|
/// single pointer.
|
|
pub fn inhibit_enum_layout_opt(&self) -> bool {
|
|
self.c() || self.int.is_some()
|
|
}
|
|
|
|
/// Returns `true` if this `#[repr()]` should inhibit struct field reordering
|
|
/// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
|
|
pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
|
|
if let Some(pack) = self.pack {
|
|
if pack.bytes() == 1 {
|
|
return true;
|
|
}
|
|
}
|
|
self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
|
|
}
|
|
|
|
/// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
|
|
pub fn inhibit_union_abi_opt(&self) -> bool {
|
|
self.c()
|
|
}
|
|
}
|
|
|
|
impl<'tcx> AdtDef {
|
|
/// Creates a new `AdtDef`.
|
|
fn new(
|
|
tcx: TyCtxt<'_>,
|
|
did: DefId,
|
|
kind: AdtKind,
|
|
variants: IndexVec<VariantIdx, VariantDef>,
|
|
repr: ReprOptions,
|
|
) -> Self {
|
|
debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
|
|
let mut flags = AdtFlags::NO_ADT_FLAGS;
|
|
|
|
if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
|
|
debug!("found non-exhaustive variant list for {:?}", did);
|
|
flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
|
|
}
|
|
|
|
flags |= match kind {
|
|
AdtKind::Enum => AdtFlags::IS_ENUM,
|
|
AdtKind::Union => AdtFlags::IS_UNION,
|
|
AdtKind::Struct => AdtFlags::IS_STRUCT,
|
|
};
|
|
|
|
if kind == AdtKind::Struct && variants[VariantIdx::new(0)].ctor_def_id.is_some() {
|
|
flags |= AdtFlags::HAS_CTOR;
|
|
}
|
|
|
|
let attrs = tcx.get_attrs(did);
|
|
if attr::contains_name(&attrs, sym::fundamental) {
|
|
flags |= AdtFlags::IS_FUNDAMENTAL;
|
|
}
|
|
if Some(did) == tcx.lang_items().phantom_data() {
|
|
flags |= AdtFlags::IS_PHANTOM_DATA;
|
|
}
|
|
if Some(did) == tcx.lang_items().owned_box() {
|
|
flags |= AdtFlags::IS_BOX;
|
|
}
|
|
if Some(did) == tcx.lang_items().manually_drop() {
|
|
flags |= AdtFlags::IS_MANUALLY_DROP;
|
|
}
|
|
if Some(did) == tcx.lang_items().arc() {
|
|
flags |= AdtFlags::IS_ARC;
|
|
}
|
|
if Some(did) == tcx.lang_items().rc() {
|
|
flags |= AdtFlags::IS_RC;
|
|
}
|
|
|
|
AdtDef { did, variants, flags, repr }
|
|
}
|
|
|
|
/// Returns `true` if this is a struct.
|
|
#[inline]
|
|
pub fn is_struct(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_STRUCT)
|
|
}
|
|
|
|
/// Returns `true` if this is a union.
|
|
#[inline]
|
|
pub fn is_union(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_UNION)
|
|
}
|
|
|
|
/// Returns `true` if this is a enum.
|
|
#[inline]
|
|
pub fn is_enum(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_ENUM)
|
|
}
|
|
|
|
/// Returns `true` if the variant list of this ADT is `#[non_exhaustive]`.
|
|
#[inline]
|
|
pub fn is_variant_list_non_exhaustive(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
|
|
}
|
|
|
|
/// Returns the kind of the ADT.
|
|
#[inline]
|
|
pub fn adt_kind(&self) -> AdtKind {
|
|
if self.is_enum() {
|
|
AdtKind::Enum
|
|
} else if self.is_union() {
|
|
AdtKind::Union
|
|
} else {
|
|
AdtKind::Struct
|
|
}
|
|
}
|
|
|
|
/// Returns a description of this abstract data type.
|
|
pub fn descr(&self) -> &'static str {
|
|
match self.adt_kind() {
|
|
AdtKind::Struct => "struct",
|
|
AdtKind::Union => "union",
|
|
AdtKind::Enum => "enum",
|
|
}
|
|
}
|
|
|
|
/// Returns a description of a variant of this abstract data type.
|
|
#[inline]
|
|
pub fn variant_descr(&self) -> &'static str {
|
|
match self.adt_kind() {
|
|
AdtKind::Struct => "struct",
|
|
AdtKind::Union => "union",
|
|
AdtKind::Enum => "variant",
|
|
}
|
|
}
|
|
|
|
/// If this function returns `true`, it implies that `is_struct` must return `true`.
|
|
#[inline]
|
|
pub fn has_ctor(&self) -> bool {
|
|
self.flags.contains(AdtFlags::HAS_CTOR)
|
|
}
|
|
|
|
/// Returns `true` if this type is `#[fundamental]` for the purposes
|
|
/// of coherence checking.
|
|
#[inline]
|
|
pub fn is_fundamental(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
|
|
}
|
|
|
|
/// Returns `true` if this is `PhantomData<T>`.
|
|
#[inline]
|
|
pub fn is_phantom_data(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
|
|
}
|
|
|
|
/// Returns `true` if this is `Arc<T>`.
|
|
pub fn is_arc(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_ARC)
|
|
}
|
|
|
|
/// Returns `true` if this is `Rc<T>`.
|
|
pub fn is_rc(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_RC)
|
|
}
|
|
|
|
/// Returns `true` if this is Box<T>.
|
|
#[inline]
|
|
pub fn is_box(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_BOX)
|
|
}
|
|
|
|
/// Returns `true` if this is `ManuallyDrop<T>`.
|
|
#[inline]
|
|
pub fn is_manually_drop(&self) -> bool {
|
|
self.flags.contains(AdtFlags::IS_MANUALLY_DROP)
|
|
}
|
|
|
|
/// Returns `true` if this type has a destructor.
|
|
pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool {
|
|
self.destructor(tcx).is_some()
|
|
}
|
|
|
|
/// Asserts this is a struct or union and returns its unique variant.
|
|
pub fn non_enum_variant(&self) -> &VariantDef {
|
|
assert!(self.is_struct() || self.is_union());
|
|
&self.variants[VariantIdx::new(0)]
|
|
}
|
|
|
|
#[inline]
|
|
pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx> {
|
|
tcx.predicates_of(self.did)
|
|
}
|
|
|
|
/// Returns an iterator over all fields contained
|
|
/// by this ADT.
|
|
#[inline]
|
|
pub fn all_fields(&self) -> impl Iterator<Item = &FieldDef> + Clone {
|
|
self.variants.iter().flat_map(|v| v.fields.iter())
|
|
}
|
|
|
|
pub fn is_payloadfree(&self) -> bool {
|
|
!self.variants.is_empty() && self.variants.iter().all(|v| v.fields.is_empty())
|
|
}
|
|
|
|
/// Return a `VariantDef` given a variant id.
|
|
pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
|
|
self.variants.iter().find(|v| v.def_id == vid).expect("variant_with_id: unknown variant")
|
|
}
|
|
|
|
/// Return a `VariantDef` given a constructor id.
|
|
pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef {
|
|
self.variants
|
|
.iter()
|
|
.find(|v| v.ctor_def_id == Some(cid))
|
|
.expect("variant_with_ctor_id: unknown variant")
|
|
}
|
|
|
|
/// Return the index of `VariantDef` given a variant id.
|
|
pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx {
|
|
self.variants
|
|
.iter_enumerated()
|
|
.find(|(_, v)| v.def_id == vid)
|
|
.expect("variant_index_with_id: unknown variant")
|
|
.0
|
|
}
|
|
|
|
/// Return the index of `VariantDef` given a constructor id.
|
|
pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx {
|
|
self.variants
|
|
.iter_enumerated()
|
|
.find(|(_, v)| v.ctor_def_id == Some(cid))
|
|
.expect("variant_index_with_ctor_id: unknown variant")
|
|
.0
|
|
}
|
|
|
|
pub fn variant_of_res(&self, res: Res) -> &VariantDef {
|
|
match res {
|
|
Res::Def(DefKind::Variant, vid) => self.variant_with_id(vid),
|
|
Res::Def(DefKind::Ctor(..), cid) => self.variant_with_ctor_id(cid),
|
|
Res::Def(DefKind::Struct, _)
|
|
| Res::Def(DefKind::Union, _)
|
|
| Res::Def(DefKind::TyAlias, _)
|
|
| Res::Def(DefKind::AssocTy, _)
|
|
| Res::SelfTy(..)
|
|
| Res::SelfCtor(..) => self.non_enum_variant(),
|
|
_ => bug!("unexpected res {:?} in variant_of_res", res),
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn eval_explicit_discr(&self, tcx: TyCtxt<'tcx>, expr_did: DefId) -> Option<Discr<'tcx>> {
|
|
let param_env = tcx.param_env(expr_did);
|
|
let repr_type = self.repr.discr_type();
|
|
match tcx.const_eval_poly(expr_did) {
|
|
Ok(val) => {
|
|
let ty = repr_type.to_ty(tcx);
|
|
if let Some(b) = val.try_to_bits_for_ty(tcx, param_env, ty) {
|
|
trace!("discriminants: {} ({:?})", b, repr_type);
|
|
Some(Discr { val: b, ty })
|
|
} else {
|
|
info!("invalid enum discriminant: {:#?}", val);
|
|
crate::mir::interpret::struct_error(
|
|
tcx.at(tcx.def_span(expr_did)),
|
|
"constant evaluation of enum discriminant resulted in non-integer",
|
|
)
|
|
.emit();
|
|
None
|
|
}
|
|
}
|
|
Err(ErrorHandled::Reported) => {
|
|
if !expr_did.is_local() {
|
|
span_bug!(
|
|
tcx.def_span(expr_did),
|
|
"variant discriminant evaluation succeeded \
|
|
in its crate but failed locally"
|
|
);
|
|
}
|
|
None
|
|
}
|
|
Err(ErrorHandled::TooGeneric) => {
|
|
span_bug!(tcx.def_span(expr_did), "enum discriminant depends on generic arguments",)
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn discriminants(
|
|
&'tcx self,
|
|
tcx: TyCtxt<'tcx>,
|
|
) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> {
|
|
let repr_type = self.repr.discr_type();
|
|
let initial = repr_type.initial_discriminant(tcx);
|
|
let mut prev_discr = None::<Discr<'tcx>>;
|
|
self.variants.iter_enumerated().map(move |(i, v)| {
|
|
let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
|
|
if let VariantDiscr::Explicit(expr_did) = v.discr {
|
|
if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
|
|
discr = new_discr;
|
|
}
|
|
}
|
|
prev_discr = Some(discr);
|
|
|
|
(i, discr)
|
|
})
|
|
}
|
|
|
|
#[inline]
|
|
pub fn variant_range(&self) -> Range<VariantIdx> {
|
|
VariantIdx::new(0)..VariantIdx::new(self.variants.len())
|
|
}
|
|
|
|
/// Computes the discriminant value used by a specific variant.
|
|
/// Unlike `discriminants`, this is (amortized) constant-time,
|
|
/// only doing at most one query for evaluating an explicit
|
|
/// discriminant (the last one before the requested variant),
|
|
/// assuming there are no constant-evaluation errors there.
|
|
#[inline]
|
|
pub fn discriminant_for_variant(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
variant_index: VariantIdx,
|
|
) -> Discr<'tcx> {
|
|
let (val, offset) = self.discriminant_def_for_variant(variant_index);
|
|
let explicit_value = val
|
|
.and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
|
|
.unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx));
|
|
explicit_value.checked_add(tcx, offset as u128).0
|
|
}
|
|
|
|
/// Yields a `DefId` for the discriminant and an offset to add to it
|
|
/// Alternatively, if there is no explicit discriminant, returns the
|
|
/// inferred discriminant directly.
|
|
pub fn discriminant_def_for_variant(&self, variant_index: VariantIdx) -> (Option<DefId>, u32) {
|
|
let mut explicit_index = variant_index.as_u32();
|
|
let expr_did;
|
|
loop {
|
|
match self.variants[VariantIdx::from_u32(explicit_index)].discr {
|
|
ty::VariantDiscr::Relative(0) => {
|
|
expr_did = None;
|
|
break;
|
|
}
|
|
ty::VariantDiscr::Relative(distance) => {
|
|
explicit_index -= distance;
|
|
}
|
|
ty::VariantDiscr::Explicit(did) => {
|
|
expr_did = Some(did);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
(expr_did, variant_index.as_u32() - explicit_index)
|
|
}
|
|
|
|
pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor> {
|
|
tcx.adt_destructor(self.did)
|
|
}
|
|
|
|
/// Returns a list of types such that `Self: Sized` if and only
|
|
/// if that type is `Sized`, or `TyErr` if this type is recursive.
|
|
///
|
|
/// Oddly enough, checking that the sized-constraint is `Sized` is
|
|
/// actually more expressive than checking all members:
|
|
/// the `Sized` trait is inductive, so an associated type that references
|
|
/// `Self` would prevent its containing ADT from being `Sized`.
|
|
///
|
|
/// Due to normalization being eager, this applies even if
|
|
/// the associated type is behind a pointer (e.g., issue #31299).
|
|
pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>] {
|
|
tcx.adt_sized_constraint(self.did).0
|
|
}
|
|
}
|
|
|
|
impl<'tcx> FieldDef {
|
|
/// Returns the type of this field. The `subst` is typically obtained
|
|
/// via the second field of `TyKind::AdtDef`.
|
|
pub fn ty(&self, tcx: TyCtxt<'tcx>, subst: SubstsRef<'tcx>) -> Ty<'tcx> {
|
|
tcx.type_of(self.did).subst(tcx, subst)
|
|
}
|
|
}
|
|
|
|
/// Represents the various closure traits in the language. This
|
|
/// will determine the type of the environment (`self`, in the
|
|
/// desugaring) argument that the closure expects.
|
|
///
|
|
/// You can get the environment type of a closure using
|
|
/// `tcx.closure_env_ty()`.
|
|
#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
#[derive(HashStable)]
|
|
pub enum ClosureKind {
|
|
// Warning: Ordering is significant here! The ordering is chosen
|
|
// because the trait Fn is a subtrait of FnMut and so in turn, and
|
|
// hence we order it so that Fn < FnMut < FnOnce.
|
|
Fn,
|
|
FnMut,
|
|
FnOnce,
|
|
}
|
|
|
|
impl<'tcx> ClosureKind {
|
|
// This is the initial value used when doing upvar inference.
|
|
pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
|
|
|
|
pub fn trait_did(&self, tcx: TyCtxt<'tcx>) -> DefId {
|
|
match *self {
|
|
ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem, None),
|
|
ClosureKind::FnMut => tcx.require_lang_item(FnMutTraitLangItem, None),
|
|
ClosureKind::FnOnce => tcx.require_lang_item(FnOnceTraitLangItem, None),
|
|
}
|
|
}
|
|
|
|
/// Returns `true` if this a type that impls this closure kind
|
|
/// must also implement `other`.
|
|
pub fn extends(self, other: ty::ClosureKind) -> bool {
|
|
match (self, other) {
|
|
(ClosureKind::Fn, ClosureKind::Fn) => true,
|
|
(ClosureKind::Fn, ClosureKind::FnMut) => true,
|
|
(ClosureKind::Fn, ClosureKind::FnOnce) => true,
|
|
(ClosureKind::FnMut, ClosureKind::FnMut) => true,
|
|
(ClosureKind::FnMut, ClosureKind::FnOnce) => true,
|
|
(ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// Returns the representative scalar type for this closure kind.
|
|
/// See `TyS::to_opt_closure_kind` for more details.
|
|
pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
|
|
match self {
|
|
ty::ClosureKind::Fn => tcx.types.i8,
|
|
ty::ClosureKind::FnMut => tcx.types.i16,
|
|
ty::ClosureKind::FnOnce => tcx.types.i32,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> TyS<'tcx> {
|
|
/// Iterator that walks `self` and any types reachable from
|
|
/// `self`, in depth-first order. Note that just walks the types
|
|
/// that appear in `self`, it does not descend into the fields of
|
|
/// structs or variants. For example:
|
|
///
|
|
/// ```notrust
|
|
/// isize => { isize }
|
|
/// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
|
|
/// [isize] => { [isize], isize }
|
|
/// ```
|
|
pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
|
|
TypeWalker::new(self)
|
|
}
|
|
|
|
/// Iterator that walks the immediate children of `self`. Hence
|
|
/// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
|
|
/// (but not `i32`, like `walk`).
|
|
pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
|
|
walk::walk_shallow(self)
|
|
}
|
|
|
|
/// Walks `ty` and any types appearing within `ty`, invoking the
|
|
/// callback `f` on each type. If the callback returns `false`, then the
|
|
/// children of the current type are ignored.
|
|
///
|
|
/// Note: prefer `ty.walk()` where possible.
|
|
pub fn maybe_walk<F>(&'tcx self, mut f: F)
|
|
where
|
|
F: FnMut(Ty<'tcx>) -> bool,
|
|
{
|
|
let mut walker = self.walk();
|
|
while let Some(ty) = walker.next() {
|
|
if !f(ty) {
|
|
walker.skip_current_subtree();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl BorrowKind {
|
|
pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
|
|
match m {
|
|
hir::Mutability::Mut => MutBorrow,
|
|
hir::Mutability::Not => ImmBorrow,
|
|
}
|
|
}
|
|
|
|
/// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
|
|
/// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
|
|
/// mutability that is stronger than necessary so that it at least *would permit* the borrow in
|
|
/// question.
|
|
pub fn to_mutbl_lossy(self) -> hir::Mutability {
|
|
match self {
|
|
MutBorrow => hir::Mutability::Mut,
|
|
ImmBorrow => hir::Mutability::Not,
|
|
|
|
// We have no type corresponding to a unique imm borrow, so
|
|
// use `&mut`. It gives all the capabilities of an `&uniq`
|
|
// and hence is a safe "over approximation".
|
|
UniqueImmBorrow => hir::Mutability::Mut,
|
|
}
|
|
}
|
|
|
|
pub fn to_user_str(&self) -> &'static str {
|
|
match *self {
|
|
MutBorrow => "mutable",
|
|
ImmBorrow => "immutable",
|
|
UniqueImmBorrow => "uniquely immutable",
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone)]
|
|
pub enum Attributes<'tcx> {
|
|
Owned(Lrc<[ast::Attribute]>),
|
|
Borrowed(&'tcx [ast::Attribute]),
|
|
}
|
|
|
|
impl<'tcx> ::std::ops::Deref for Attributes<'tcx> {
|
|
type Target = [ast::Attribute];
|
|
|
|
fn deref(&self) -> &[ast::Attribute] {
|
|
match self {
|
|
&Attributes::Owned(ref data) => &data,
|
|
&Attributes::Borrowed(data) => data,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, PartialEq, Eq)]
|
|
pub enum ImplOverlapKind {
|
|
/// These impls are always allowed to overlap.
|
|
Permitted {
|
|
/// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
|
|
marker: bool,
|
|
},
|
|
/// These impls are allowed to overlap, but that raises
|
|
/// an issue #33140 future-compatibility warning.
|
|
///
|
|
/// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
|
|
/// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
|
|
///
|
|
/// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
|
|
/// that difference, making what reduces to the following set of impls:
|
|
///
|
|
/// ```
|
|
/// trait Trait {}
|
|
/// impl Trait for dyn Send + Sync {}
|
|
/// impl Trait for dyn Sync + Send {}
|
|
/// ```
|
|
///
|
|
/// Obviously, once we made these types be identical, that code causes a coherence
|
|
/// error and a fairly big headache for us. However, luckily for us, the trait
|
|
/// `Trait` used in this case is basically a marker trait, and therefore having
|
|
/// overlapping impls for it is sound.
|
|
///
|
|
/// To handle this, we basically regard the trait as a marker trait, with an additional
|
|
/// future-compatibility warning. To avoid accidentally "stabilizing" this feature,
|
|
/// it has the following restrictions:
|
|
///
|
|
/// 1. The trait must indeed be a marker-like trait (i.e., no items), and must be
|
|
/// positive impls.
|
|
/// 2. The trait-ref of both impls must be equal.
|
|
/// 3. The trait-ref of both impls must be a trait object type consisting only of
|
|
/// marker traits.
|
|
/// 4. Neither of the impls can have any where-clauses.
|
|
///
|
|
/// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
|
|
Issue33140,
|
|
}
|
|
|
|
impl<'tcx> TyCtxt<'tcx> {
|
|
pub fn body_tables(self, body: hir::BodyId) -> &'tcx TypeckTables<'tcx> {
|
|
self.typeck_tables_of(self.hir().body_owner_def_id(body))
|
|
}
|
|
|
|
/// Returns an iterator of the `DefId`s for all body-owners in this
|
|
/// crate. If you would prefer to iterate over the bodies
|
|
/// themselves, you can do `self.hir().krate().body_ids.iter()`.
|
|
pub fn body_owners(self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'tcx {
|
|
self.hir()
|
|
.krate()
|
|
.body_ids
|
|
.iter()
|
|
.map(move |&body_id| self.hir().body_owner_def_id(body_id))
|
|
}
|
|
|
|
pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
|
|
par_iter(&self.hir().krate().body_ids)
|
|
.for_each(|&body_id| f(self.hir().body_owner_def_id(body_id)));
|
|
}
|
|
|
|
pub fn provided_trait_methods(self, id: DefId) -> impl 'tcx + Iterator<Item = &'tcx AssocItem> {
|
|
self.associated_items(id)
|
|
.in_definition_order()
|
|
.filter(|item| item.kind == AssocKind::Method && item.defaultness.has_value())
|
|
}
|
|
|
|
pub fn trait_relevant_for_never(self, did: DefId) -> bool {
|
|
self.associated_items(did).in_definition_order().any(|item| item.relevant_for_never())
|
|
}
|
|
|
|
pub fn opt_item_name(self, def_id: DefId) -> Option<Ident> {
|
|
self.hir().as_local_hir_id(def_id).and_then(|hir_id| self.hir().get(hir_id).ident())
|
|
}
|
|
|
|
pub fn opt_associated_item(self, def_id: DefId) -> Option<AssocItem> {
|
|
let is_associated_item = if let Some(hir_id) = self.hir().as_local_hir_id(def_id) {
|
|
match self.hir().get(hir_id) {
|
|
Node::TraitItem(_) | Node::ImplItem(_) => true,
|
|
_ => false,
|
|
}
|
|
} else {
|
|
match self.def_kind(def_id) {
|
|
Some(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy) => true,
|
|
_ => false,
|
|
}
|
|
};
|
|
|
|
is_associated_item.then(|| self.associated_item(def_id))
|
|
}
|
|
|
|
pub fn field_index(self, hir_id: hir::HirId, tables: &TypeckTables<'_>) -> usize {
|
|
tables.field_indices().get(hir_id).cloned().expect("no index for a field")
|
|
}
|
|
|
|
pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
|
|
variant.fields.iter().position(|field| self.hygienic_eq(ident, field.ident, variant.def_id))
|
|
}
|
|
|
|
/// Returns `true` if the impls are the same polarity and the trait either
|
|
/// has no items or is annotated #[marker] and prevents item overrides.
|
|
pub fn impls_are_allowed_to_overlap(
|
|
self,
|
|
def_id1: DefId,
|
|
def_id2: DefId,
|
|
) -> Option<ImplOverlapKind> {
|
|
// If either trait impl references an error, they're allowed to overlap,
|
|
// as one of them essentially doesn't exist.
|
|
if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
|
|
|| self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
|
|
{
|
|
return Some(ImplOverlapKind::Permitted { marker: false });
|
|
}
|
|
|
|
match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
|
|
(ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
|
|
// `#[rustc_reservation_impl]` impls don't overlap with anything
|
|
debug!(
|
|
"impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (reservations)",
|
|
def_id1, def_id2
|
|
);
|
|
return Some(ImplOverlapKind::Permitted { marker: false });
|
|
}
|
|
(ImplPolarity::Positive, ImplPolarity::Negative)
|
|
| (ImplPolarity::Negative, ImplPolarity::Positive) => {
|
|
// `impl AutoTrait for Type` + `impl !AutoTrait for Type`
|
|
debug!(
|
|
"impls_are_allowed_to_overlap({:?}, {:?}) - None (differing polarities)",
|
|
def_id1, def_id2
|
|
);
|
|
return None;
|
|
}
|
|
(ImplPolarity::Positive, ImplPolarity::Positive)
|
|
| (ImplPolarity::Negative, ImplPolarity::Negative) => {}
|
|
};
|
|
|
|
let is_marker_overlap = {
|
|
let is_marker_impl = |def_id: DefId| -> bool {
|
|
let trait_ref = self.impl_trait_ref(def_id);
|
|
trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
|
|
};
|
|
is_marker_impl(def_id1) && is_marker_impl(def_id2)
|
|
};
|
|
|
|
if is_marker_overlap {
|
|
debug!(
|
|
"impls_are_allowed_to_overlap({:?}, {:?}) = Some(Permitted) (marker overlap)",
|
|
def_id1, def_id2
|
|
);
|
|
Some(ImplOverlapKind::Permitted { marker: true })
|
|
} else {
|
|
if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
|
|
if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
|
|
if self_ty1 == self_ty2 {
|
|
debug!(
|
|
"impls_are_allowed_to_overlap({:?}, {:?}) - issue #33140 HACK",
|
|
def_id1, def_id2
|
|
);
|
|
return Some(ImplOverlapKind::Issue33140);
|
|
} else {
|
|
debug!(
|
|
"impls_are_allowed_to_overlap({:?}, {:?}) - found {:?} != {:?}",
|
|
def_id1, def_id2, self_ty1, self_ty2
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
debug!("impls_are_allowed_to_overlap({:?}, {:?}) = None", def_id1, def_id2);
|
|
None
|
|
}
|
|
}
|
|
|
|
/// Returns `ty::VariantDef` if `res` refers to a struct,
|
|
/// or variant or their constructors, panics otherwise.
|
|
pub fn expect_variant_res(self, res: Res) -> &'tcx VariantDef {
|
|
match res {
|
|
Res::Def(DefKind::Variant, did) => {
|
|
let enum_did = self.parent(did).unwrap();
|
|
self.adt_def(enum_did).variant_with_id(did)
|
|
}
|
|
Res::Def(DefKind::Struct, did) | Res::Def(DefKind::Union, did) => {
|
|
self.adt_def(did).non_enum_variant()
|
|
}
|
|
Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_did) => {
|
|
let variant_did = self.parent(variant_ctor_did).unwrap();
|
|
let enum_did = self.parent(variant_did).unwrap();
|
|
self.adt_def(enum_did).variant_with_ctor_id(variant_ctor_did)
|
|
}
|
|
Res::Def(DefKind::Ctor(CtorOf::Struct, ..), ctor_did) => {
|
|
let struct_did = self.parent(ctor_did).expect("struct ctor has no parent");
|
|
self.adt_def(struct_did).non_enum_variant()
|
|
}
|
|
_ => bug!("expect_variant_res used with unexpected res {:?}", res),
|
|
}
|
|
}
|
|
|
|
pub fn item_name(self, id: DefId) -> Symbol {
|
|
if id.index == CRATE_DEF_INDEX {
|
|
self.original_crate_name(id.krate)
|
|
} else {
|
|
let def_key = self.def_key(id);
|
|
match def_key.disambiguated_data.data {
|
|
// The name of a constructor is that of its parent.
|
|
rustc_hir::definitions::DefPathData::Ctor => {
|
|
self.item_name(DefId { krate: id.krate, index: def_key.parent.unwrap() })
|
|
}
|
|
_ => def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
|
|
bug!("item_name: no name for {:?}", self.def_path(id));
|
|
}),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
|
|
pub fn instance_mir(self, instance: ty::InstanceDef<'tcx>) -> ReadOnlyBodyAndCache<'tcx, 'tcx> {
|
|
match instance {
|
|
ty::InstanceDef::Item(did) => self.optimized_mir(did).unwrap_read_only(),
|
|
ty::InstanceDef::VtableShim(..)
|
|
| ty::InstanceDef::ReifyShim(..)
|
|
| ty::InstanceDef::Intrinsic(..)
|
|
| ty::InstanceDef::FnPtrShim(..)
|
|
| ty::InstanceDef::Virtual(..)
|
|
| ty::InstanceDef::ClosureOnceShim { .. }
|
|
| ty::InstanceDef::DropGlue(..)
|
|
| ty::InstanceDef::CloneShim(..) => self.mir_shims(instance).unwrap_read_only(),
|
|
}
|
|
}
|
|
|
|
/// Gets the attributes of a definition.
|
|
pub fn get_attrs(self, did: DefId) -> Attributes<'tcx> {
|
|
if let Some(id) = self.hir().as_local_hir_id(did) {
|
|
Attributes::Borrowed(self.hir().attrs(id))
|
|
} else {
|
|
Attributes::Owned(self.item_attrs(did))
|
|
}
|
|
}
|
|
|
|
/// Determines whether an item is annotated with an attribute.
|
|
pub fn has_attr(self, did: DefId, attr: Symbol) -> bool {
|
|
attr::contains_name(&self.get_attrs(did), attr)
|
|
}
|
|
|
|
/// Returns `true` if this is an `auto trait`.
|
|
pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
|
|
self.trait_def(trait_def_id).has_auto_impl
|
|
}
|
|
|
|
pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
|
|
self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
|
|
}
|
|
|
|
/// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
|
|
/// If it implements no trait, returns `None`.
|
|
pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
|
|
self.impl_trait_ref(def_id).map(|tr| tr.def_id)
|
|
}
|
|
|
|
/// If the given defid describes a method belonging to an impl, returns the
|
|
/// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
|
|
pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
|
|
self.opt_associated_item(def_id).and_then(|trait_item| match trait_item.container {
|
|
TraitContainer(_) => None,
|
|
ImplContainer(def_id) => Some(def_id),
|
|
})
|
|
}
|
|
|
|
/// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
|
|
/// with the name of the crate containing the impl.
|
|
pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
|
|
if impl_did.is_local() {
|
|
let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
|
|
Ok(self.hir().span(hir_id))
|
|
} else {
|
|
Err(self.crate_name(impl_did.krate))
|
|
}
|
|
}
|
|
|
|
/// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
|
|
/// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
|
|
/// definition's parent/scope to perform comparison.
|
|
pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
|
|
// We could use `Ident::eq` here, but we deliberately don't. The name
|
|
// comparison fails frequently, and we want to avoid the expensive
|
|
// `normalize_to_macros_2_0()` calls required for the span comparison whenever possible.
|
|
use_name.name == def_name.name
|
|
&& use_name
|
|
.span
|
|
.ctxt()
|
|
.hygienic_eq(def_name.span.ctxt(), self.expansion_that_defined(def_parent_def_id))
|
|
}
|
|
|
|
fn expansion_that_defined(self, scope: DefId) -> ExpnId {
|
|
match scope.as_local() {
|
|
Some(scope) => self.hir().definitions().expansion_that_defined(scope),
|
|
None => ExpnId::root(),
|
|
}
|
|
}
|
|
|
|
pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
|
|
ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope));
|
|
ident
|
|
}
|
|
|
|
pub fn adjust_ident_and_get_scope(
|
|
self,
|
|
mut ident: Ident,
|
|
scope: DefId,
|
|
block: hir::HirId,
|
|
) -> (Ident, DefId) {
|
|
let scope =
|
|
match ident.span.normalize_to_macros_2_0_and_adjust(self.expansion_that_defined(scope))
|
|
{
|
|
Some(actual_expansion) => {
|
|
self.hir().definitions().parent_module_of_macro_def(actual_expansion)
|
|
}
|
|
None => self.parent_module(block).to_def_id(),
|
|
};
|
|
(ident, scope)
|
|
}
|
|
|
|
pub fn is_object_safe(self, key: DefId) -> bool {
|
|
self.object_safety_violations(key).is_empty()
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, HashStable)]
|
|
pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
|
|
|
|
/// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition.
|
|
pub fn is_impl_trait_defn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
|
|
if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
|
|
if let Node::Item(item) = tcx.hir().get(hir_id) {
|
|
if let hir::ItemKind::OpaqueTy(ref opaque_ty) = item.kind {
|
|
return opaque_ty.impl_trait_fn;
|
|
}
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
pub fn provide(providers: &mut ty::query::Providers<'_>) {
|
|
context::provide(providers);
|
|
erase_regions::provide(providers);
|
|
layout::provide(providers);
|
|
super::util::bug::provide(providers);
|
|
*providers = ty::query::Providers {
|
|
trait_impls_of: trait_def::trait_impls_of_provider,
|
|
all_local_trait_impls: trait_def::all_local_trait_impls,
|
|
..*providers
|
|
};
|
|
}
|
|
|
|
/// A map for the local crate mapping each type to a vector of its
|
|
/// inherent impls. This is not meant to be used outside of coherence;
|
|
/// rather, you should request the vector for a specific type via
|
|
/// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
|
|
/// (constructing this map requires touching the entire crate).
|
|
#[derive(Clone, Debug, Default, HashStable)]
|
|
pub struct CrateInherentImpls {
|
|
pub inherent_impls: DefIdMap<Vec<DefId>>,
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
|
pub struct SymbolName {
|
|
// FIXME: we don't rely on interning or equality here - better have
|
|
// this be a `&'tcx str`.
|
|
pub name: Symbol,
|
|
}
|
|
|
|
impl SymbolName {
|
|
pub fn new(name: &str) -> SymbolName {
|
|
SymbolName { name: Symbol::intern(name) }
|
|
}
|
|
}
|
|
|
|
impl PartialOrd for SymbolName {
|
|
fn partial_cmp(&self, other: &SymbolName) -> Option<Ordering> {
|
|
self.name.as_str().partial_cmp(&other.name.as_str())
|
|
}
|
|
}
|
|
|
|
/// Ordering must use the chars to ensure reproducible builds.
|
|
impl Ord for SymbolName {
|
|
fn cmp(&self, other: &SymbolName) -> Ordering {
|
|
self.name.as_str().cmp(&other.name.as_str())
|
|
}
|
|
}
|
|
|
|
impl fmt::Display for SymbolName {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
fmt::Display::fmt(&self.name, fmt)
|
|
}
|
|
}
|
|
|
|
impl fmt::Debug for SymbolName {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
fmt::Display::fmt(&self.name, fmt)
|
|
}
|
|
}
|