src/librustc/ty/context.rs

   1 // ignore-tidy-filelength
   2 //! Type context book-keeping.
   3
   4 use crate::arena::Arena;
   5 use crate::dep_graph::DepGraph;
   6 use crate::dep_graph::{self, DepNode, DepConstructor};
   7 use crate::session::Session;
   8 use crate::session::config::{BorrowckMode, OutputFilenames};
   9 use crate::session::config::CrateType;
  10 use crate::middle;
  11 use crate::middle::lang_items::PanicLocationLangItem;
  12 use crate::hir::{self, TraitCandidate, HirId, ItemKind, ItemLocalId, Node};
  13 use crate::hir::def::{Res, DefKind, Export};
  14 use crate::hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE};
  15 use crate::hir::map as hir_map;
  16 use crate::hir::map::DefPathHash;
  17 use crate::lint::{self, Lint};
  18 use crate::ich::{StableHashingContext, NodeIdHashingMode};
  19 use crate::infer::canonical::{Canonical, CanonicalVarInfo, CanonicalVarInfos};
  20 use crate::infer::outlives::free_region_map::FreeRegionMap;
  21 use crate::middle::cstore::CrateStoreDyn;
  22 use crate::middle::cstore::EncodedMetadata;
  23 use crate::middle::lang_items;
  24 use crate::middle::resolve_lifetime::{self, ObjectLifetimeDefault};
  25 use crate::middle::stability;
  26 use crate::mir::{BodyAndCache, Field, interpret, Local, Place, PlaceElem, ProjectionKind, Promoted};
  27 use crate::mir::interpret::{ConstValue, Allocation, Scalar};
  28 use crate::ty::subst::{GenericArg, InternalSubsts, SubstsRef, Subst};
  29 use crate::ty::ReprOptions;
  30 use crate::traits;
  31 use crate::traits::{Clause, Clauses, GoalKind, Goal, Goals};
  32 use crate::ty::{self, DefIdTree, Ty, TypeAndMut};
  33 use crate::ty::{TyS, TyKind, List};
  34 use crate::ty::{AdtKind, AdtDef, Region, Const};
  35 use crate::ty::{PolyFnSig, InferTy, ParamTy, ProjectionTy, ExistentialPredicate, Predicate};
  36 use crate::ty::RegionKind;
  37 use crate::ty::{TyVar, TyVid, IntVar, IntVid, FloatVar, FloatVid, ConstVid};
  38 use crate::ty::TyKind::*;
  39 use crate::ty::{InferConst, ParamConst};
  40 use crate::ty::GenericParamDefKind;
  41 use crate::ty::layout::{LayoutDetails, TargetDataLayout, VariantIdx};
  42 use crate::ty::query;
  43 use crate::ty::steal::Steal;
  44 use crate::ty::subst::{UserSubsts, GenericArgKind};
  45 use crate::ty::{BoundVar, BindingMode};
  46 use crate::ty::CanonicalPolyFnSig;
  47 use crate::util::common::ErrorReported;
  48 use crate::util::nodemap::{DefIdMap, DefIdSet, ItemLocalMap, ItemLocalSet, NodeMap};
  49 use crate::util::nodemap::{FxHashMap, FxHashSet};
  50
  51 use errors::DiagnosticBuilder;
  52 use arena::SyncDroplessArena;
  53 use smallvec::SmallVec;
  54 use rustc_data_structures::profiling::SelfProfilerRef;
  55 use rustc_data_structures::stable_hasher::{
  56     HashStable, StableHasher, StableVec, hash_stable_hashmap,
  57 };
  58 use rustc_index::vec::{Idx, IndexVec};
  59 use rustc_data_structures::sharded::ShardedHashMap;
  60 use rustc_data_structures::sync::{Lrc, Lock, WorkerLocal};
  61 use std::any::Any;
  62 use std::borrow::Borrow;
  63 use std::cmp::Ordering;
  64 use std::collections::hash_map::{self, Entry};
  65 use std::hash::{Hash, Hasher};
  66 use std::fmt;
  67 use std::mem;
  68 use std::ops::{Deref, Bound};
  69 use std::iter;
  70 use std::sync::Arc;
  71 use rustc_target::spec::abi;
  72 use rustc_macros::HashStable;
  73 use syntax::ast;
  74 use syntax::attr;
  75 use syntax::source_map::MultiSpan;
  76 use syntax::symbol::{Symbol, kw, sym};
  77 use syntax_pos::Span;
  78 use syntax::expand::allocator::AllocatorKind;
  79
  80 pub struct AllArenas {
  81     pub interner: SyncDroplessArena,
  82 }
  83
  84 impl AllArenas {
  85     pub fn new() -> Self {
  86         AllArenas {
  87             interner: SyncDroplessArena::default(),
  88         }
  89     }
  90 }
  91
  92 type InternedSet<'tcx, T> = ShardedHashMap<Interned<'tcx, T>, ()>;
  93
  94 pub struct CtxtInterners<'tcx> {
  95     /// The arena that types, regions, etc. are allocated from.
  96     arena: &'tcx SyncDroplessArena,
  97
  98     /// Specifically use a speedy hash algorithm for these hash sets, since
  99     /// they're accessed quite often.
 100     type_: InternedSet<'tcx, TyS<'tcx>>,
 101     type_list: InternedSet<'tcx, List<Ty<'tcx>>>,
 102     substs: InternedSet<'tcx, InternalSubsts<'tcx>>,
 103     canonical_var_infos: InternedSet<'tcx, List<CanonicalVarInfo>>,
 104     region: InternedSet<'tcx, RegionKind>,
 105     existential_predicates: InternedSet<'tcx, List<ExistentialPredicate<'tcx>>>,
 106     predicates: InternedSet<'tcx, List<Predicate<'tcx>>>,
 107     clauses: InternedSet<'tcx, List<Clause<'tcx>>>,
 108     goal: InternedSet<'tcx, GoalKind<'tcx>>,
 109     goal_list: InternedSet<'tcx, List<Goal<'tcx>>>,
 110     projs: InternedSet<'tcx, List<ProjectionKind>>,
 111     place_elems: InternedSet<'tcx, List<PlaceElem<'tcx>>>,
 112     const_: InternedSet<'tcx, Const<'tcx>>,
 113 }
 114
 115 impl<'tcx> CtxtInterners<'tcx> {
 116     fn new(arena: &'tcx SyncDroplessArena) -> CtxtInterners<'tcx> {
 117         CtxtInterners {
 118             arena,
 119             type_: Default::default(),
 120             type_list: Default::default(),
 121             substs: Default::default(),
 122             region: Default::default(),
 123             existential_predicates: Default::default(),
 124             canonical_var_infos: Default::default(),
 125             predicates: Default::default(),
 126             clauses: Default::default(),
 127             goal: Default::default(),
 128             goal_list: Default::default(),
 129             projs: Default::default(),
 130             place_elems: Default::default(),
 131             const_: Default::default(),
 132         }
 133     }
 134
 135     /// Interns a type.
 136     #[allow(rustc::usage_of_ty_tykind)]
 137     #[inline(never)]
 138     fn intern_ty(&self,
 139         kind: TyKind<'tcx>
 140     ) -> Ty<'tcx> {
 141         self.type_.intern(kind, |kind| {
 142             let flags = super::flags::FlagComputation::for_kind(&kind);
 143
 144             let ty_struct = TyS {
 145                 kind,
 146                 flags: flags.flags,
 147                 outer_exclusive_binder: flags.outer_exclusive_binder,
 148             };
 149
 150             Interned(self.arena.alloc(ty_struct))
 151         }).0
 152     }
 153 }
 154
 155 pub struct CommonTypes<'tcx> {
 156     pub unit: Ty<'tcx>,
 157     pub bool: Ty<'tcx>,
 158     pub char: Ty<'tcx>,
 159     pub isize: Ty<'tcx>,
 160     pub i8: Ty<'tcx>,
 161     pub i16: Ty<'tcx>,
 162     pub i32: Ty<'tcx>,
 163     pub i64: Ty<'tcx>,
 164     pub i128: Ty<'tcx>,
 165     pub usize: Ty<'tcx>,
 166     pub u8: Ty<'tcx>,
 167     pub u16: Ty<'tcx>,
 168     pub u32: Ty<'tcx>,
 169     pub u64: Ty<'tcx>,
 170     pub u128: Ty<'tcx>,
 171     pub f32: Ty<'tcx>,
 172     pub f64: Ty<'tcx>,
 173     pub never: Ty<'tcx>,
 174     pub self_param: Ty<'tcx>,
 175     pub err: Ty<'tcx>,
 176
 177     /// Dummy type used for the `Self` of a `TraitRef` created for converting
 178     /// a trait object, and which gets removed in `ExistentialTraitRef`.
 179     /// This type must not appear anywhere in other converted types.
 180     pub trait_object_dummy_self: Ty<'tcx>,
 181 }
 182
 183 pub struct CommonLifetimes<'tcx> {
 184     pub re_empty: Region<'tcx>,
 185     pub re_static: Region<'tcx>,
 186     pub re_erased: Region<'tcx>,
 187 }
 188
 189 pub struct CommonConsts<'tcx> {
 190     pub err: &'tcx Const<'tcx>,
 191 }
 192
 193 pub struct LocalTableInContext<'a, V> {
 194     local_id_root: Option<DefId>,
 195     data: &'a ItemLocalMap<V>
 196 }
 197
 198 /// Validate that the given HirId (respectively its `local_id` part) can be
 199 /// safely used as a key in the tables of a TypeckTable. For that to be
 200 /// the case, the HirId must have the same `owner` as all the other IDs in
 201 /// this table (signified by `local_id_root`). Otherwise the HirId
 202 /// would be in a different frame of reference and using its `local_id`
 203 /// would result in lookup errors, or worse, in silently wrong data being
 204 /// stored/returned.
 205 fn validate_hir_id_for_typeck_tables(local_id_root: Option<DefId>,
 206                                      hir_id: hir::HirId,
 207                                      mut_access: bool) {
 208     if let Some(local_id_root) = local_id_root {
 209         if hir_id.owner != local_id_root.index {
 210             ty::tls::with(|tcx| {
 211                 bug!("node {} with HirId::owner {:?} cannot be placed in \
 212                         TypeckTables with local_id_root {:?}",
 213                         tcx.hir().node_to_string(hir_id),
 214                         DefId::local(hir_id.owner),
 215                         local_id_root)
 216             });
 217         }
 218     } else {
 219         // We use "Null Object" TypeckTables in some of the analysis passes.
 220         // These are just expected to be empty and their `local_id_root` is
 221         // `None`. Therefore we cannot verify whether a given `HirId` would
 222         // be a valid key for the given table. Instead we make sure that
 223         // nobody tries to write to such a Null Object table.
 224         if mut_access {
 225             bug!("access to invalid TypeckTables")
 226         }
 227     }
 228 }
 229
 230 impl<'a, V> LocalTableInContext<'a, V> {
 231     pub fn contains_key(&self, id: hir::HirId) -> bool {
 232         validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
 233         self.data.contains_key(&id.local_id)
 234     }
 235
 236     pub fn get(&self, id: hir::HirId) -> Option<&V> {
 237         validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
 238         self.data.get(&id.local_id)
 239     }
 240
 241     pub fn iter(&self) -> hash_map::Iter<'_, hir::ItemLocalId, V> {
 242         self.data.iter()
 243     }
 244 }
 245
 246 impl<'a, V> ::std::ops::Index<hir::HirId> for LocalTableInContext<'a, V> {
 247     type Output = V;
 248
 249     fn index(&self, key: hir::HirId) -> &V {
 250         self.get(key).expect("LocalTableInContext: key not found")
 251     }
 252 }
 253
 254 pub struct LocalTableInContextMut<'a, V> {
 255     local_id_root: Option<DefId>,
 256     data: &'a mut ItemLocalMap<V>
 257 }
 258
 259 impl<'a, V> LocalTableInContextMut<'a, V> {
 260     pub fn get_mut(&mut self, id: hir::HirId) -> Option<&mut V> {
 261         validate_hir_id_for_typeck_tables(self.local_id_root, id, true);
 262         self.data.get_mut(&id.local_id)
 263     }
 264
 265     pub fn entry(&mut self, id: hir::HirId) -> Entry<'_, hir::ItemLocalId, V> {
 266         validate_hir_id_for_typeck_tables(self.local_id_root, id, true);
 267         self.data.entry(id.local_id)
 268     }
 269
 270     pub fn insert(&mut self, id: hir::HirId, val: V) -> Option<V> {
 271         validate_hir_id_for_typeck_tables(self.local_id_root, id, true);
 272         self.data.insert(id.local_id, val)
 273     }
 274
 275     pub fn remove(&mut self, id: hir::HirId) -> Option<V> {
 276         validate_hir_id_for_typeck_tables(self.local_id_root, id, true);
 277         self.data.remove(&id.local_id)
 278     }
 279 }
 280
 281 /// All information necessary to validate and reveal an `impl Trait`.
 282 #[derive(RustcEncodable, RustcDecodable, Debug, HashStable)]
 283 pub struct ResolvedOpaqueTy<'tcx> {
 284     /// The revealed type as seen by this function.
 285     pub concrete_type: Ty<'tcx>,
 286     /// Generic parameters on the opaque type as passed by this function.
 287     /// For `type Foo<A, B> = impl Bar<A, B>; fn foo<T, U>() -> Foo<T, U> { .. }`
 288     /// this is `[T, U]`, not `[A, B]`.
 289     pub substs: SubstsRef<'tcx>,
 290 }
 291
 292 /// Whenever a value may be live across a generator yield, the type of that value winds up in the
 293 /// `GeneratorInteriorTypeCause` struct. This struct adds additional information about such
 294 /// captured types that can be useful for diagnostics. In particular, it stores the span that
 295 /// caused a given type to be recorded, along with the scope that enclosed the value (which can
 296 /// be used to find the await that the value is live across).
 297 ///
 298 /// For example:
 299 ///
 300 /// ```ignore (pseudo-Rust)
 301 /// async move {
 302 ///     let x: T = ...;
 303 ///     foo.await
 304 ///     ...
 305 /// }
 306 /// ```
 307 ///
 308 /// Here, we would store the type `T`, the span of the value `x`, and the "scope-span" for
 309 /// the scope that contains `x`.
 310 #[derive(RustcEncodable, RustcDecodable, Clone, Debug, Eq, Hash, PartialEq)]
 311 #[derive(HashStable, TypeFoldable)]
 312 pub struct GeneratorInteriorTypeCause<'tcx> {
 313     /// Type of the captured binding.
 314     pub ty: Ty<'tcx>,
 315     /// Span of the binding that was captured.
 316     pub span: Span,
 317     /// Span of the scope of the captured binding.
 318     pub scope_span: Option<Span>,
 319 }
 320
 321 #[derive(RustcEncodable, RustcDecodable, Debug)]
 322 pub struct TypeckTables<'tcx> {
 323     /// The HirId::owner all ItemLocalIds in this table are relative to.
 324     pub local_id_root: Option<DefId>,
 325
 326     /// Resolved definitions for `<T>::X` associated paths and
 327     /// method calls, including those of overloaded operators.
 328     type_dependent_defs: ItemLocalMap<Result<(DefKind, DefId), ErrorReported>>,
 329
 330     /// Resolved field indices for field accesses in expressions (`S { field }`, `obj.field`)
 331     /// or patterns (`S { field }`). The index is often useful by itself, but to learn more
 332     /// about the field you also need definition of the variant to which the field
 333     /// belongs, but it may not exist if it's a tuple field (`tuple.0`).
 334     field_indices: ItemLocalMap<usize>,
 335
 336     /// Stores the types for various nodes in the AST. Note that this table
 337     /// is not guaranteed to be populated until after typeck. See
 338     /// typeck::check::fn_ctxt for details.
 339     node_types: ItemLocalMap<Ty<'tcx>>,
 340
 341     /// Stores the type parameters which were substituted to obtain the type
 342     /// of this node. This only applies to nodes that refer to entities
 343     /// parameterized by type parameters, such as generic fns, types, or
 344     /// other items.
 345     node_substs: ItemLocalMap<SubstsRef<'tcx>>,
 346
 347     /// This will either store the canonicalized types provided by the user
 348     /// or the substitutions that the user explicitly gave (if any) attached
 349     /// to `id`. These will not include any inferred values. The canonical form
 350     /// is used to capture things like `_` or other unspecified values.
 351     ///
 352     /// For example, if the user wrote `foo.collect::<Vec<_>>()`, then the
 353     /// canonical substitutions would include only `for<X> { Vec<X> }`.
 354     ///
 355     /// See also `AscribeUserType` statement in MIR.
 356     user_provided_types: ItemLocalMap<CanonicalUserType<'tcx>>,
 357
 358     /// Stores the canonicalized types provided by the user. See also
 359     /// `AscribeUserType` statement in MIR.
 360     pub user_provided_sigs: DefIdMap<CanonicalPolyFnSig<'tcx>>,
 361
 362     adjustments: ItemLocalMap<Vec<ty::adjustment::Adjustment<'tcx>>>,
 363
 364     /// Stores the actual binding mode for all instances of hir::BindingAnnotation.
 365     pat_binding_modes: ItemLocalMap<BindingMode>,
 366
 367     /// Stores the types which were implicitly dereferenced in pattern binding modes
 368     /// for later usage in HAIR lowering. For example,
 369     ///
 370     /// ```
 371     /// match &&Some(5i32) {
 372     ///     Some(n) => {},
 373     ///     _ => {},
 374     /// }
 375     /// ```
 376     /// leads to a `vec![&&Option<i32>, &Option<i32>]`. Empty vectors are not stored.
 377     ///
 378     /// See:
 379     /// https://github.com/rust-lang/rfcs/blob/master/text/2005-match-ergonomics.md#definitions
 380     pat_adjustments: ItemLocalMap<Vec<Ty<'tcx>>>,
 381
 382     /// Borrows
 383     pub upvar_capture_map: ty::UpvarCaptureMap<'tcx>,
 384
 385     /// Records the reasons that we picked the kind of each closure;
 386     /// not all closures are present in the map.
 387     closure_kind_origins: ItemLocalMap<(Span, ast::Name)>,
 388
 389     /// For each fn, records the "liberated" types of its arguments
 390     /// and return type. Liberated means that all bound regions
 391     /// (including late-bound regions) are replaced with free
 392     /// equivalents. This table is not used in codegen (since regions
 393     /// are erased there) and hence is not serialized to metadata.
 394     liberated_fn_sigs: ItemLocalMap<ty::FnSig<'tcx>>,
 395
 396     /// For each FRU expression, record the normalized types of the fields
 397     /// of the struct - this is needed because it is non-trivial to
 398     /// normalize while preserving regions. This table is used only in
 399     /// MIR construction and hence is not serialized to metadata.
 400     fru_field_types: ItemLocalMap<Vec<Ty<'tcx>>>,
 401
 402     /// For every coercion cast we add the HIR node ID of the cast
 403     /// expression to this set.
 404     coercion_casts: ItemLocalSet,
 405
 406     /// Set of trait imports actually used in the method resolution.
 407     /// This is used for warning unused imports. During type
 408     /// checking, this `Lrc` should not be cloned: it must have a ref-count
 409     /// of 1 so that we can insert things into the set mutably.
 410     pub used_trait_imports: Lrc<DefIdSet>,
 411
 412     /// If any errors occurred while type-checking this body,
 413     /// this field will be set to `true`.
 414     pub tainted_by_errors: bool,
 415
 416     /// Stores the free-region relationships that were deduced from
 417     /// its where-clauses and parameter types. These are then
 418     /// read-again by borrowck.
 419     pub free_region_map: FreeRegionMap<'tcx>,
 420
 421     /// All the opaque types that are restricted to concrete types
 422     /// by this function.
 423     pub concrete_opaque_types: FxHashMap<DefId, ResolvedOpaqueTy<'tcx>>,
 424
 425     /// Given the closure ID this map provides the list of UpvarIDs used by it.
 426     /// The upvarID contains the HIR node ID and it also contains the full path
 427     /// leading to the member of the struct or tuple that is used instead of the
 428     /// entire variable.
 429     pub upvar_list: ty::UpvarListMap,
 430
 431     /// Stores the type, span and optional scope span of all types
 432     /// that are live across the yield of this generator (if a generator).
 433     pub generator_interior_types: Vec<GeneratorInteriorTypeCause<'tcx>>,
 434 }
 435
 436 impl<'tcx> TypeckTables<'tcx> {
 437     pub fn empty(local_id_root: Option<DefId>) -> TypeckTables<'tcx> {
 438         TypeckTables {
 439             local_id_root,
 440             type_dependent_defs: Default::default(),
 441             field_indices: Default::default(),
 442             user_provided_types: Default::default(),
 443             user_provided_sigs: Default::default(),
 444             node_types: Default::default(),
 445             node_substs: Default::default(),
 446             adjustments: Default::default(),
 447             pat_binding_modes: Default::default(),
 448             pat_adjustments: Default::default(),
 449             upvar_capture_map: Default::default(),
 450             closure_kind_origins: Default::default(),
 451             liberated_fn_sigs: Default::default(),
 452             fru_field_types: Default::default(),
 453             coercion_casts: Default::default(),
 454             used_trait_imports: Lrc::new(Default::default()),
 455             tainted_by_errors: false,
 456             free_region_map: Default::default(),
 457             concrete_opaque_types: Default::default(),
 458             upvar_list: Default::default(),
 459             generator_interior_types: Default::default(),
 460         }
 461     }
 462
 463     /// Returns the final resolution of a `QPath` in an `Expr` or `Pat` node.
 464     pub fn qpath_res(&self, qpath: &hir::QPath, id: hir::HirId) -> Res {
 465         match *qpath {
 466             hir::QPath::Resolved(_, ref path) => path.res,
 467             hir::QPath::TypeRelative(..) => self.type_dependent_def(id)
 468                 .map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)),
 469         }
 470     }
 471
 472     pub fn type_dependent_defs(
 473         &self,
 474     ) -> LocalTableInContext<'_, Result<(DefKind, DefId), ErrorReported>> {
 475         LocalTableInContext {
 476             local_id_root: self.local_id_root,
 477             data: &self.type_dependent_defs
 478         }
 479     }
 480
 481     pub fn type_dependent_def(&self, id: HirId) -> Option<(DefKind, DefId)> {
 482         validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
 483         self.type_dependent_defs.get(&id.local_id).cloned().and_then(|r| r.ok())
 484     }
 485
 486     pub fn type_dependent_def_id(&self, id: HirId) -> Option<DefId> {
 487         self.type_dependent_def(id).map(|(_, def_id)| def_id)
 488     }
 489
 490     pub fn type_dependent_defs_mut(
 491         &mut self,
 492     ) -> LocalTableInContextMut<'_, Result<(DefKind, DefId), ErrorReported>> {
 493         LocalTableInContextMut {
 494             local_id_root: self.local_id_root,
 495             data: &mut self.type_dependent_defs
 496         }
 497     }
 498
 499     pub fn field_indices(&self) -> LocalTableInContext<'_, usize> {
 500         LocalTableInContext {
 501             local_id_root: self.local_id_root,
 502             data: &self.field_indices
 503         }
 504     }
 505
 506     pub fn field_indices_mut(&mut self) -> LocalTableInContextMut<'_, usize> {
 507         LocalTableInContextMut {
 508             local_id_root: self.local_id_root,
 509             data: &mut self.field_indices
 510         }
 511     }
 512
 513     pub fn user_provided_types(
 514         &self
 515     ) -> LocalTableInContext<'_, CanonicalUserType<'tcx>> {
 516         LocalTableInContext {
 517             local_id_root: self.local_id_root,
 518             data: &self.user_provided_types
 519         }
 520     }
 521
 522     pub fn user_provided_types_mut(
 523         &mut self
 524     ) -> LocalTableInContextMut<'_, CanonicalUserType<'tcx>> {
 525         LocalTableInContextMut {
 526             local_id_root: self.local_id_root,
 527             data: &mut self.user_provided_types
 528         }
 529     }
 530
 531     pub fn node_types(&self) -> LocalTableInContext<'_, Ty<'tcx>> {
 532         LocalTableInContext {
 533             local_id_root: self.local_id_root,
 534             data: &self.node_types
 535         }
 536     }
 537
 538     pub fn node_types_mut(&mut self) -> LocalTableInContextMut<'_, Ty<'tcx>> {
 539         LocalTableInContextMut {
 540             local_id_root: self.local_id_root,
 541             data: &mut self.node_types
 542         }
 543     }
 544
 545     pub fn node_type(&self, id: hir::HirId) -> Ty<'tcx> {
 546         self.node_type_opt(id).unwrap_or_else(||
 547             bug!("node_type: no type for node `{}`",
 548                  tls::with(|tcx| tcx.hir().node_to_string(id)))
 549         )
 550     }
 551
 552     pub fn node_type_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
 553         validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
 554         self.node_types.get(&id.local_id).cloned()
 555     }
 556
 557     pub fn node_substs_mut(&mut self) -> LocalTableInContextMut<'_, SubstsRef<'tcx>> {
 558         LocalTableInContextMut {
 559             local_id_root: self.local_id_root,
 560             data: &mut self.node_substs
 561         }
 562     }
 563
 564     pub fn node_substs(&self, id: hir::HirId) -> SubstsRef<'tcx> {
 565         validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
 566         self.node_substs.get(&id.local_id).cloned().unwrap_or_else(|| InternalSubsts::empty())
 567     }
 568
 569     pub fn node_substs_opt(&self, id: hir::HirId) -> Option<SubstsRef<'tcx>> {
 570         validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
 571         self.node_substs.get(&id.local_id).cloned()
 572     }
 573
 574     // Returns the type of a pattern as a monotype. Like @expr_ty, this function
 575     // doesn't provide type parameter substitutions.
 576     pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
 577         self.node_type(pat.hir_id)
 578     }
 579
 580     pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
 581         self.node_type_opt(pat.hir_id)
 582     }
 583
 584     // Returns the type of an expression as a monotype.
 585     //
 586     // NB (1): This is the PRE-ADJUSTMENT TYPE for the expression.  That is, in
 587     // some cases, we insert `Adjustment` annotations such as auto-deref or
 588     // auto-ref.  The type returned by this function does not consider such
 589     // adjustments.  See `expr_ty_adjusted()` instead.
 590     //
 591     // NB (2): This type doesn't provide type parameter substitutions; e.g., if you
 592     // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
 593     // instead of "fn(ty) -> T with T = isize".
 594     pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
 595         self.node_type(expr.hir_id)
 596     }
 597
 598     pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
 599         self.node_type_opt(expr.hir_id)
 600     }
 601
 602     pub fn adjustments(&self) -> LocalTableInContext<'_, Vec<ty::adjustment::Adjustment<'tcx>>> {
 603         LocalTableInContext {
 604             local_id_root: self.local_id_root,
 605             data: &self.adjustments
 606         }
 607     }
 608
 609     pub fn adjustments_mut(&mut self)
 610                            -> LocalTableInContextMut<'_, Vec<ty::adjustment::Adjustment<'tcx>>> {
 611         LocalTableInContextMut {
 612             local_id_root: self.local_id_root,
 613             data: &mut self.adjustments
 614         }
 615     }
 616
 617     pub fn expr_adjustments(&self, expr: &hir::Expr)
 618                             -> &[ty::adjustment::Adjustment<'tcx>] {
 619         validate_hir_id_for_typeck_tables(self.local_id_root, expr.hir_id, false);
 620         self.adjustments.get(&expr.hir_id.local_id).map_or(&[], |a| &a[..])
 621     }
 622
 623     /// Returns the type of `expr`, considering any `Adjustment`
 624     /// entry recorded for that expression.
 625     pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> Ty<'tcx> {
 626         self.expr_adjustments(expr)
 627             .last()
 628             .map_or_else(|| self.expr_ty(expr), |adj| adj.target)
 629     }
 630
 631     pub fn expr_ty_adjusted_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
 632         self.expr_adjustments(expr)
 633             .last()
 634             .map(|adj| adj.target)
 635             .or_else(|| self.expr_ty_opt(expr))
 636     }
 637
 638     pub fn is_method_call(&self, expr: &hir::Expr) -> bool {
 639         // Only paths and method calls/overloaded operators have
 640         // entries in type_dependent_defs, ignore the former here.
 641         if let hir::ExprKind::Path(_) = expr.kind {
 642             return false;
 643         }
 644
 645         match self.type_dependent_defs().get(expr.hir_id) {
 646             Some(Ok((DefKind::Method, _))) => true,
 647             _ => false
 648         }
 649     }
 650
 651     pub fn pat_binding_modes(&self) -> LocalTableInContext<'_, BindingMode> {
 652         LocalTableInContext {
 653             local_id_root: self.local_id_root,
 654             data: &self.pat_binding_modes
 655         }
 656     }
 657
 658     pub fn pat_binding_modes_mut(&mut self)
 659                            -> LocalTableInContextMut<'_, BindingMode> {
 660         LocalTableInContextMut {
 661             local_id_root: self.local_id_root,
 662             data: &mut self.pat_binding_modes
 663         }
 664     }
 665
 666     pub fn pat_adjustments(&self) -> LocalTableInContext<'_, Vec<Ty<'tcx>>> {
 667         LocalTableInContext {
 668             local_id_root: self.local_id_root,
 669             data: &self.pat_adjustments,
 670         }
 671     }
 672
 673     pub fn pat_adjustments_mut(&mut self)
 674                                -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
 675         LocalTableInContextMut {
 676             local_id_root: self.local_id_root,
 677             data: &mut self.pat_adjustments,
 678         }
 679     }
 680
 681     pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> ty::UpvarCapture<'tcx> {
 682         self.upvar_capture_map[&upvar_id]
 683     }
 684
 685     pub fn closure_kind_origins(&self) -> LocalTableInContext<'_, (Span, ast::Name)> {
 686         LocalTableInContext {
 687             local_id_root: self.local_id_root,
 688             data: &self.closure_kind_origins
 689         }
 690     }
 691
 692     pub fn closure_kind_origins_mut(&mut self) -> LocalTableInContextMut<'_, (Span, ast::Name)> {
 693         LocalTableInContextMut {
 694             local_id_root: self.local_id_root,
 695             data: &mut self.closure_kind_origins
 696         }
 697     }
 698
 699     pub fn liberated_fn_sigs(&self) -> LocalTableInContext<'_, ty::FnSig<'tcx>> {
 700         LocalTableInContext {
 701             local_id_root: self.local_id_root,
 702             data: &self.liberated_fn_sigs
 703         }
 704     }
 705
 706     pub fn liberated_fn_sigs_mut(&mut self) -> LocalTableInContextMut<'_, ty::FnSig<'tcx>> {
 707         LocalTableInContextMut {
 708             local_id_root: self.local_id_root,
 709             data: &mut self.liberated_fn_sigs
 710         }
 711     }
 712
 713     pub fn fru_field_types(&self) -> LocalTableInContext<'_, Vec<Ty<'tcx>>> {
 714         LocalTableInContext {
 715             local_id_root: self.local_id_root,
 716             data: &self.fru_field_types
 717         }
 718     }
 719
 720     pub fn fru_field_types_mut(&mut self) -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
 721         LocalTableInContextMut {
 722             local_id_root: self.local_id_root,
 723             data: &mut self.fru_field_types
 724         }
 725     }
 726
 727     pub fn is_coercion_cast(&self, hir_id: hir::HirId) -> bool {
 728         validate_hir_id_for_typeck_tables(self.local_id_root, hir_id, true);
 729         self.coercion_casts.contains(&hir_id.local_id)
 730     }
 731
 732     pub fn set_coercion_cast(&mut self, id: ItemLocalId) {
 733         self.coercion_casts.insert(id);
 734     }
 735
 736     pub fn coercion_casts(&self) -> &ItemLocalSet {
 737         &self.coercion_casts
 738     }
 739
 740 }
 741
 742 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TypeckTables<'tcx> {
 743     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
 744         let ty::TypeckTables {
 745             local_id_root,
 746             ref type_dependent_defs,
 747             ref field_indices,
 748             ref user_provided_types,
 749             ref user_provided_sigs,
 750             ref node_types,
 751             ref node_substs,
 752             ref adjustments,
 753             ref pat_binding_modes,
 754             ref pat_adjustments,
 755             ref upvar_capture_map,
 756             ref closure_kind_origins,
 757             ref liberated_fn_sigs,
 758             ref fru_field_types,
 759
 760             ref coercion_casts,
 761
 762             ref used_trait_imports,
 763             tainted_by_errors,
 764             ref free_region_map,
 765             ref concrete_opaque_types,
 766             ref upvar_list,
 767             ref generator_interior_types,
 768
 769         } = *self;
 770
 771         hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| {
 772             type_dependent_defs.hash_stable(hcx, hasher);
 773             field_indices.hash_stable(hcx, hasher);
 774             user_provided_types.hash_stable(hcx, hasher);
 775             user_provided_sigs.hash_stable(hcx, hasher);
 776             node_types.hash_stable(hcx, hasher);
 777             node_substs.hash_stable(hcx, hasher);
 778             adjustments.hash_stable(hcx, hasher);
 779             pat_binding_modes.hash_stable(hcx, hasher);
 780             pat_adjustments.hash_stable(hcx, hasher);
 781             hash_stable_hashmap(hcx, hasher, upvar_capture_map, |up_var_id, hcx| {
 782                 let ty::UpvarId {
 783                     var_path,
 784                     closure_expr_id
 785                 } = *up_var_id;
 786
 787                 let local_id_root =
 788                     local_id_root.expect("trying to hash invalid TypeckTables");
 789
 790                 let var_owner_def_id = DefId {
 791                     krate: local_id_root.krate,
 792                     index: var_path.hir_id.owner,
 793                 };
 794                 let closure_def_id = DefId {
 795                     krate: local_id_root.krate,
 796                     index: closure_expr_id.to_def_id().index,
 797                 };
 798                 (hcx.def_path_hash(var_owner_def_id),
 799                  var_path.hir_id.local_id,
 800                  hcx.def_path_hash(closure_def_id))
 801             });
 802
 803             closure_kind_origins.hash_stable(hcx, hasher);
 804             liberated_fn_sigs.hash_stable(hcx, hasher);
 805             fru_field_types.hash_stable(hcx, hasher);
 806             coercion_casts.hash_stable(hcx, hasher);
 807             used_trait_imports.hash_stable(hcx, hasher);
 808             tainted_by_errors.hash_stable(hcx, hasher);
 809             free_region_map.hash_stable(hcx, hasher);
 810             concrete_opaque_types.hash_stable(hcx, hasher);
 811             upvar_list.hash_stable(hcx, hasher);
 812             generator_interior_types.hash_stable(hcx, hasher);
 813         })
 814     }
 815 }
 816
 817 rustc_index::newtype_index! {
 818     pub struct UserTypeAnnotationIndex {
 819         derive [HashStable]
 820         DEBUG_FORMAT = "UserType({})",
 821         const START_INDEX = 0,
 822     }
 823 }
 824
 825 /// Mapping of type annotation indices to canonical user type annotations.
 826 pub type CanonicalUserTypeAnnotations<'tcx> =
 827     IndexVec<UserTypeAnnotationIndex, CanonicalUserTypeAnnotation<'tcx>>;
 828
 829 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable, Lift)]
 830 pub struct CanonicalUserTypeAnnotation<'tcx> {
 831     pub user_ty: CanonicalUserType<'tcx>,
 832     pub span: Span,
 833     pub inferred_ty: Ty<'tcx>,
 834 }
 835
 836 /// Canonicalized user type annotation.
 837 pub type CanonicalUserType<'tcx> = Canonical<'tcx, UserType<'tcx>>;
 838
 839 impl CanonicalUserType<'tcx> {
 840     /// Returns `true` if this represents a substitution of the form `[?0, ?1, ?2]`,
 841     /// i.e., each thing is mapped to a canonical variable with the same index.
 842     pub fn is_identity(&self) -> bool {
 843         match self.value {
 844             UserType::Ty(_) => false,
 845             UserType::TypeOf(_, user_substs) => {
 846                 if user_substs.user_self_ty.is_some() {
 847                     return false;
 848                 }
 849
 850                 user_substs.substs.iter().zip(BoundVar::new(0)..).all(|(kind, cvar)| {
 851                     match kind.unpack() {
 852                         GenericArgKind::Type(ty) => match ty.kind {
 853                             ty::Bound(debruijn, b) => {
 854                                 // We only allow a `ty::INNERMOST` index in substitutions.
 855                                 assert_eq!(debruijn, ty::INNERMOST);
 856                                 cvar == b.var
 857                             }
 858                             _ => false,
 859                         },
 860
 861                         GenericArgKind::Lifetime(r) => match r {
 862                             ty::ReLateBound(debruijn, br) => {
 863                                 // We only allow a `ty::INNERMOST` index in substitutions.
 864                                 assert_eq!(*debruijn, ty::INNERMOST);
 865                                 cvar == br.assert_bound_var()
 866                             }
 867                             _ => false,
 868                         },
 869
 870                         GenericArgKind::Const(ct) => match ct.val {
 871                             ty::ConstKind::Bound(debruijn, b) => {
 872                                 // We only allow a `ty::INNERMOST` index in substitutions.
 873                                 assert_eq!(debruijn, ty::INNERMOST);
 874                                 cvar == b
 875                             }
 876                             _ => false,
 877                         },
 878                     }
 879                 })
 880             },
 881         }
 882     }
 883 }
 884
 885 /// A user-given type annotation attached to a constant. These arise
 886 /// from constants that are named via paths, like `Foo::<A>::new` and
 887 /// so forth.
 888 #[derive(Copy, Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]
 889 #[derive(HashStable, TypeFoldable, Lift)]
 890 pub enum UserType<'tcx> {
 891     Ty(Ty<'tcx>),
 892
 893     /// The canonical type is the result of `type_of(def_id)` with the
 894     /// given substitutions applied.
 895     TypeOf(DefId, UserSubsts<'tcx>),
 896 }
 897
 898 impl<'tcx> CommonTypes<'tcx> {
 899     fn new(interners: &CtxtInterners<'tcx>) -> CommonTypes<'tcx> {
 900         let mk = |ty| interners.intern_ty(ty);
 901
 902         CommonTypes {
 903             unit: mk(Tuple(List::empty())),
 904             bool: mk(Bool),
 905             char: mk(Char),
 906             never: mk(Never),
 907             err: mk(Error),
 908             isize: mk(Int(ast::IntTy::Isize)),
 909             i8: mk(Int(ast::IntTy::I8)),
 910             i16: mk(Int(ast::IntTy::I16)),
 911             i32: mk(Int(ast::IntTy::I32)),
 912             i64: mk(Int(ast::IntTy::I64)),
 913             i128: mk(Int(ast::IntTy::I128)),
 914             usize: mk(Uint(ast::UintTy::Usize)),
 915             u8: mk(Uint(ast::UintTy::U8)),
 916             u16: mk(Uint(ast::UintTy::U16)),
 917             u32: mk(Uint(ast::UintTy::U32)),
 918             u64: mk(Uint(ast::UintTy::U64)),
 919             u128: mk(Uint(ast::UintTy::U128)),
 920             f32: mk(Float(ast::FloatTy::F32)),
 921             f64: mk(Float(ast::FloatTy::F64)),
 922             self_param: mk(ty::Param(ty::ParamTy {
 923                 index: 0,
 924                 name: kw::SelfUpper,
 925             })),
 926
 927             trait_object_dummy_self: mk(Infer(ty::FreshTy(0))),
 928         }
 929     }
 930 }
 931
 932 impl<'tcx> CommonLifetimes<'tcx> {
 933     fn new(interners: &CtxtInterners<'tcx>) -> CommonLifetimes<'tcx> {
 934         let mk = |r| {
 935             interners.region.intern(r, |r| {
 936                 Interned(interners.arena.alloc(r))
 937             }).0
 938         };
 939
 940         CommonLifetimes {
 941             re_empty: mk(RegionKind::ReEmpty),
 942             re_static: mk(RegionKind::ReStatic),
 943             re_erased: mk(RegionKind::ReErased),
 944         }
 945     }
 946 }
 947
 948 impl<'tcx> CommonConsts<'tcx> {
 949     fn new(interners: &CtxtInterners<'tcx>, types: &CommonTypes<'tcx>) -> CommonConsts<'tcx> {
 950         let mk_const = |c| {
 951             interners.const_.intern(c, |c| {
 952                 Interned(interners.arena.alloc(c))
 953             }).0
 954         };
 955
 956         CommonConsts {
 957             err: mk_const(ty::Const {
 958                 val: ty::ConstKind::Value(ConstValue::Scalar(Scalar::zst())),
 959                 ty: types.err,
 960             }),
 961         }
 962     }
 963 }
 964
 965 // This struct contains information regarding the `ReFree(FreeRegion)` corresponding to a lifetime
 966 // conflict.
 967 #[derive(Debug)]
 968 pub struct FreeRegionInfo {
 969     // def id corresponding to FreeRegion
 970     pub def_id: DefId,
 971     // the bound region corresponding to FreeRegion
 972     pub boundregion: ty::BoundRegion,
 973     // checks if bound region is in Impl Item
 974     pub is_impl_item: bool,
 975 }
 976
 977 /// The central data structure of the compiler. It stores references
 978 /// to the various **arenas** and also houses the results of the
 979 /// various **compiler queries** that have been performed. See the
 980 /// [rustc guide] for more details.
 981 ///
 982 /// [rustc guide]: https://rust-lang.github.io/rustc-guide/ty.html
 983 #[derive(Copy, Clone)]
 984 #[rustc_diagnostic_item = "TyCtxt"]
 985 pub struct TyCtxt<'tcx> {
 986     gcx: &'tcx GlobalCtxt<'tcx>,
 987 }
 988
 989 impl<'tcx> Deref for TyCtxt<'tcx> {
 990     type Target = &'tcx GlobalCtxt<'tcx>;
 991     #[inline(always)]
 992     fn deref(&self) -> &Self::Target {
 993         &self.gcx
 994     }
 995 }
 996
 997 pub struct GlobalCtxt<'tcx> {
 998     pub arena: &'tcx WorkerLocal<Arena<'tcx>>,
 999
1000     interners: CtxtInterners<'tcx>,
1001
1002     cstore: Box<CrateStoreDyn>,
1003
1004     pub sess: &'tcx Session,
1005
1006     pub lint_store: Lrc<lint::LintStore>,
1007
1008     pub dep_graph: DepGraph,
1009
1010     pub prof: SelfProfilerRef,
1011
1012     /// Common types, pre-interned for your convenience.
1013     pub types: CommonTypes<'tcx>,
1014
1015     /// Common lifetimes, pre-interned for your convenience.
1016     pub lifetimes: CommonLifetimes<'tcx>,
1017
1018     /// Common consts, pre-interned for your convenience.
1019     pub consts: CommonConsts<'tcx>,
1020
1021     /// Resolutions of `extern crate` items produced by resolver.
1022     extern_crate_map: NodeMap<CrateNum>,
1023
1024     /// Map indicating what traits are in scope for places where this
1025     /// is relevant; generated by resolve.
1026     trait_map: FxHashMap<DefIndex,
1027                          FxHashMap<ItemLocalId,
1028                                    StableVec<TraitCandidate>>>,
1029
1030     /// Export map produced by name resolution.
1031     export_map: FxHashMap<DefId, Vec<Export<hir::HirId>>>,
1032
1033     hir_map: hir_map::Map<'tcx>,
1034
1035     /// A map from `DefPathHash` -> `DefId`. Includes `DefId`s from the local crate
1036     /// as well as all upstream crates. Only populated in incremental mode.
1037     pub def_path_hash_to_def_id: Option<FxHashMap<DefPathHash, DefId>>,
1038
1039     pub queries: query::Queries<'tcx>,
1040
1041     maybe_unused_trait_imports: FxHashSet<DefId>,
1042     maybe_unused_extern_crates: Vec<(DefId, Span)>,
1043     /// A map of glob use to a set of names it actually imports. Currently only
1044     /// used in save-analysis.
1045     glob_map: FxHashMap<DefId, FxHashSet<ast::Name>>,
1046     /// Extern prelude entries. The value is `true` if the entry was introduced
1047     /// via `extern crate` item and not `--extern` option or compiler built-in.
1048     pub extern_prelude: FxHashMap<ast::Name, bool>,
1049
1050     // Internal cache for metadata decoding. No need to track deps on this.
1051     pub rcache: Lock<FxHashMap<ty::CReaderCacheKey, Ty<'tcx>>>,
1052
1053     /// Caches the results of trait selection. This cache is used
1054     /// for things that do not have to do with the parameters in scope.
1055     pub selection_cache: traits::SelectionCache<'tcx>,
1056
1057     /// Caches the results of trait evaluation. This cache is used
1058     /// for things that do not have to do with the parameters in scope.
1059     /// Merge this with `selection_cache`?
1060     pub evaluation_cache: traits::EvaluationCache<'tcx>,
1061
1062     /// The definite name of the current crate after taking into account
1063     /// attributes, commandline parameters, etc.
1064     pub crate_name: Symbol,
1065
1066     /// Data layout specification for the current target.
1067     pub data_layout: TargetDataLayout,
1068
1069     /// `#[stable]` and `#[unstable]` attributes
1070     stability_interner: ShardedHashMap<&'tcx attr::Stability, ()>,
1071
1072     /// `#[rustc_const_stable]` and `#[rustc_const_unstable]` attributes
1073     const_stability_interner: ShardedHashMap<&'tcx attr::ConstStability, ()>,
1074
1075     /// Stores the value of constants (and deduplicates the actual memory)
1076     allocation_interner: ShardedHashMap<&'tcx Allocation, ()>,
1077
1078     pub alloc_map: Lock<interpret::AllocMap<'tcx>>,
1079
1080     layout_interner: ShardedHashMap<&'tcx LayoutDetails, ()>,
1081
1082     output_filenames: Arc<OutputFilenames>,
1083 }
1084
1085 impl<'tcx> TyCtxt<'tcx> {
1086     #[inline(always)]
1087     pub fn hir(self) -> &'tcx hir_map::Map<'tcx> {
1088         &self.hir_map
1089     }
1090
1091     pub fn alloc_steal_mir(self, mir: BodyAndCache<'tcx>) -> &'tcx Steal<BodyAndCache<'tcx>> {
1092         self.arena.alloc(Steal::new(mir))
1093     }
1094
1095     pub fn alloc_steal_promoted(self, promoted: IndexVec<Promoted, BodyAndCache<'tcx>>) ->
1096         &'tcx Steal<IndexVec<Promoted, BodyAndCache<'tcx>>> {
1097         self.arena.alloc(Steal::new(promoted))
1098     }
1099
1100     pub fn intern_promoted(self, promoted: IndexVec<Promoted, BodyAndCache<'tcx>>) ->
1101         &'tcx IndexVec<Promoted, BodyAndCache<'tcx>> {
1102         self.arena.alloc(promoted)
1103     }
1104
1105     pub fn alloc_adt_def(
1106         self,
1107         did: DefId,
1108         kind: AdtKind,
1109         variants: IndexVec<VariantIdx, ty::VariantDef>,
1110         repr: ReprOptions,
1111     ) -> &'tcx ty::AdtDef {
1112         let def = ty::AdtDef::new(self, did, kind, variants, repr);
1113         self.arena.alloc(def)
1114     }
1115
1116     pub fn intern_const_alloc(self, alloc: Allocation) -> &'tcx Allocation {
1117         self.allocation_interner.intern(alloc, |alloc| {
1118             self.arena.alloc(alloc)
1119         })
1120     }
1121
1122     /// Allocates a read-only byte or string literal for `mir::interpret`.
1123     pub fn allocate_bytes(self, bytes: &[u8]) -> interpret::AllocId {
1124         // Create an allocation that just contains these bytes.
1125         let alloc = interpret::Allocation::from_byte_aligned_bytes(bytes);
1126         let alloc = self.intern_const_alloc(alloc);
1127         self.alloc_map.lock().create_memory_alloc(alloc)
1128     }
1129
1130     pub fn intern_stability(self, stab: attr::Stability) -> &'tcx attr::Stability {
1131         self.stability_interner.intern(stab, |stab| {
1132             self.arena.alloc(stab)
1133         })
1134     }
1135
1136     pub fn intern_const_stability(self, stab: attr::ConstStability) -> &'tcx attr::ConstStability {
1137         self.const_stability_interner.intern(stab, |stab| {
1138             self.arena.alloc(stab)
1139         })
1140     }
1141
1142     pub fn intern_layout(self, layout: LayoutDetails) -> &'tcx LayoutDetails {
1143         self.layout_interner.intern(layout, |layout| {
1144             self.arena.alloc(layout)
1145         })
1146     }
1147
1148     /// Returns a range of the start/end indices specified with the
1149     /// `rustc_layout_scalar_valid_range` attribute.
1150     pub fn layout_scalar_valid_range(self, def_id: DefId) -> (Bound<u128>, Bound<u128>) {
1151         let attrs = self.get_attrs(def_id);
1152         let get = |name| {
1153             let attr = match attrs.iter().find(|a| a.check_name(name)) {
1154                 Some(attr) => attr,
1155                 None => return Bound::Unbounded,
1156             };
1157             for meta in attr.meta_item_list().expect("rustc_layout_scalar_valid_range takes args") {
1158                 match meta.literal().expect("attribute takes lit").kind {
1159                     ast::LitKind::Int(a, _) => return Bound::Included(a),
1160                     _ => span_bug!(attr.span, "rustc_layout_scalar_valid_range expects int arg"),
1161                 }
1162             }
1163             span_bug!(attr.span, "no arguments to `rustc_layout_scalar_valid_range` attribute");
1164         };
1165         (get(sym::rustc_layout_scalar_valid_range_start),
1166          get(sym::rustc_layout_scalar_valid_range_end))
1167     }
1168
1169     pub fn lift<T: ?Sized + Lift<'tcx>>(self, value: &T) -> Option<T::Lifted> {
1170         value.lift_to_tcx(self)
1171     }
1172
1173     /// Creates a type context and call the closure with a `TyCtxt` reference
1174     /// to the context. The closure enforces that the type context and any interned
1175     /// value (types, substs, etc.) can only be used while `ty::tls` has a valid
1176     /// reference to the context, to allow formatting values that need it.
1177     pub fn create_global_ctxt(
1178         s: &'tcx Session,
1179         lint_store: Lrc<lint::LintStore>,
1180         local_providers: ty::query::Providers<'tcx>,
1181         extern_providers: ty::query::Providers<'tcx>,
1182         arenas: &'tcx AllArenas,
1183         arena: &'tcx WorkerLocal<Arena<'tcx>>,
1184         resolutions: ty::ResolverOutputs,
1185         hir: hir_map::Map<'tcx>,
1186         on_disk_query_result_cache: query::OnDiskCache<'tcx>,
1187         crate_name: &str,
1188         output_filenames: &OutputFilenames,
1189     ) -> GlobalCtxt<'tcx> {
1190         let data_layout = TargetDataLayout::parse(&s.target.target).unwrap_or_else(|err| {
1191             s.fatal(&err);
1192         });
1193         let interners = CtxtInterners::new(&arenas.interner);
1194         let common_types = CommonTypes::new(&interners);
1195         let common_lifetimes = CommonLifetimes::new(&interners);
1196         let common_consts = CommonConsts::new(&interners, &common_types);
1197         let dep_graph = hir.dep_graph.clone();
1198         let cstore = resolutions.cstore;
1199         let crates = cstore.crates_untracked();
1200         let max_cnum = crates.iter().map(|c| c.as_usize()).max().unwrap_or(0);
1201         let mut providers = IndexVec::from_elem_n(extern_providers, max_cnum + 1);
1202         providers[LOCAL_CRATE] = local_providers;
1203
1204         let def_path_hash_to_def_id = if s.opts.build_dep_graph() {
1205             let def_path_tables = crates
1206                 .iter()
1207                 .map(|&cnum| (cnum, cstore.def_path_table(cnum)))
1208                 .chain(iter::once((LOCAL_CRATE, hir.definitions().def_path_table())));
1209
1210             // Precompute the capacity of the hashmap so we don't have to
1211             // re-allocate when populating it.
1212             let capacity = def_path_tables.clone().map(|(_, t)| t.size()).sum::<usize>();
1213
1214             let mut map: FxHashMap<_, _> = FxHashMap::with_capacity_and_hasher(
1215                 capacity,
1216                 ::std::default::Default::default()
1217             );
1218
1219             for (cnum, def_path_table) in def_path_tables {
1220                 def_path_table.add_def_path_hashes_to(cnum, &mut map);
1221             }
1222
1223             Some(map)
1224         } else {
1225             None
1226         };
1227
1228         let mut trait_map: FxHashMap<_, FxHashMap<_, _>> = FxHashMap::default();
1229         for (k, v) in resolutions.trait_map {
1230             let hir_id = hir.node_to_hir_id(k);
1231             let map = trait_map.entry(hir_id.owner).or_default();
1232             map.insert(hir_id.local_id, StableVec::new(v));
1233         }
1234
1235         GlobalCtxt {
1236             sess: s,
1237             lint_store,
1238             cstore,
1239             arena,
1240             interners,
1241             dep_graph,
1242             prof: s.prof.clone(),
1243             types: common_types,
1244             lifetimes: common_lifetimes,
1245             consts: common_consts,
1246             extern_crate_map: resolutions.extern_crate_map,
1247             trait_map,
1248             export_map: resolutions.export_map.into_iter().map(|(k, v)| {
1249                 let exports: Vec<_> = v.into_iter().map(|e| {
1250                     e.map_id(|id| hir.node_to_hir_id(id))
1251                 }).collect();
1252                 (k, exports)
1253             }).collect(),
1254             maybe_unused_trait_imports:
1255                 resolutions.maybe_unused_trait_imports
1256                     .into_iter()
1257                     .map(|id| hir.local_def_id_from_node_id(id))
1258                     .collect(),
1259             maybe_unused_extern_crates:
1260                 resolutions.maybe_unused_extern_crates
1261                     .into_iter()
1262                     .map(|(id, sp)| (hir.local_def_id_from_node_id(id), sp))
1263                     .collect(),
1264             glob_map: resolutions.glob_map.into_iter().map(|(id, names)| {
1265                 (hir.local_def_id_from_node_id(id), names)
1266             }).collect(),
1267             extern_prelude: resolutions.extern_prelude,
1268             hir_map: hir,
1269             def_path_hash_to_def_id,
1270             queries: query::Queries::new(
1271                 providers,
1272                 extern_providers,
1273                 on_disk_query_result_cache,
1274             ),
1275             rcache: Default::default(),
1276             selection_cache: Default::default(),
1277             evaluation_cache: Default::default(),
1278             crate_name: Symbol::intern(crate_name),
1279             data_layout,
1280             layout_interner: Default::default(),
1281             stability_interner: Default::default(),
1282             const_stability_interner: Default::default(),
1283             allocation_interner: Default::default(),
1284             alloc_map: Lock::new(interpret::AllocMap::new()),
1285             output_filenames: Arc::new(output_filenames.clone()),
1286         }
1287     }
1288
1289     pub fn consider_optimizing<T: Fn() -> String>(&self, msg: T) -> bool {
1290         let cname = self.crate_name(LOCAL_CRATE).as_str();
1291         self.sess.consider_optimizing(&cname, msg)
1292     }
1293
1294     pub fn lib_features(self) -> &'tcx middle::lib_features::LibFeatures {
1295         self.get_lib_features(LOCAL_CRATE)
1296     }
1297
1298     /// Obtain all lang items of this crate and all dependencies (recursively)
1299     pub fn lang_items(self) -> &'tcx middle::lang_items::LanguageItems {
1300         self.get_lang_items(LOCAL_CRATE)
1301     }
1302
1303     /// Obtain the given diagnostic item's `DefId`. Use `is_diagnostic_item` if you just want to
1304     /// compare against another `DefId`, since `is_diagnostic_item` is cheaper.
1305     pub fn get_diagnostic_item(self, name: Symbol) -> Option<DefId> {
1306         self.all_diagnostic_items(LOCAL_CRATE).get(&name).copied()
1307     }
1308
1309     /// Check whether the diagnostic item with the given `name` has the given `DefId`.
1310     pub fn is_diagnostic_item(self, name: Symbol, did: DefId) -> bool {
1311         self.diagnostic_items(did.krate).get(&name) == Some(&did)
1312     }
1313
1314     pub fn stability(self) -> &'tcx stability::Index<'tcx> {
1315         self.stability_index(LOCAL_CRATE)
1316     }
1317
1318     pub fn crates(self) -> &'tcx [CrateNum] {
1319         self.all_crate_nums(LOCAL_CRATE)
1320     }
1321
1322     pub fn allocator_kind(self) -> Option<AllocatorKind> {
1323         self.cstore.allocator_kind()
1324     }
1325
1326     pub fn features(self) -> &'tcx rustc_feature::Features {
1327         self.features_query(LOCAL_CRATE)
1328     }
1329
1330     pub fn def_key(self, id: DefId) -> hir_map::DefKey {
1331         if id.is_local() {
1332             self.hir().def_key(id)
1333         } else {
1334             self.cstore.def_key(id)
1335         }
1336     }
1337
1338     /// Converts a `DefId` into its fully expanded `DefPath` (every
1339     /// `DefId` is really just an interned `DefPath`).
1340     ///
1341     /// Note that if `id` is not local to this crate, the result will
1342     ///  be a non-local `DefPath`.
1343     pub fn def_path(self, id: DefId) -> hir_map::DefPath {
1344         if id.is_local() {
1345             self.hir().def_path(id)
1346         } else {
1347             self.cstore.def_path(id)
1348         }
1349     }
1350
1351     /// Returns whether or not the crate with CrateNum 'cnum'
1352     /// is marked as a private dependency
1353     pub fn is_private_dep(self, cnum: CrateNum) -> bool {
1354         if cnum == LOCAL_CRATE {
1355             false
1356         } else {
1357             self.cstore.crate_is_private_dep_untracked(cnum)
1358         }
1359     }
1360
1361     #[inline]
1362     pub fn def_path_hash(self, def_id: DefId) -> hir_map::DefPathHash {
1363         if def_id.is_local() {
1364             self.hir().definitions().def_path_hash(def_id.index)
1365         } else {
1366             self.cstore.def_path_hash(def_id)
1367         }
1368     }
1369
1370     pub fn def_path_debug_str(self, def_id: DefId) -> String {
1371         // We are explicitly not going through queries here in order to get
1372         // crate name and disambiguator since this code is called from debug!()
1373         // statements within the query system and we'd run into endless
1374         // recursion otherwise.
1375         let (crate_name, crate_disambiguator) = if def_id.is_local() {
1376             (self.crate_name.clone(),
1377              self.sess.local_crate_disambiguator())
1378         } else {
1379             (self.cstore.crate_name_untracked(def_id.krate),
1380              self.cstore.crate_disambiguator_untracked(def_id.krate))
1381         };
1382
1383         format!("{}[{}]{}",
1384                 crate_name,
1385                 // Don't print the whole crate disambiguator. That's just
1386                 // annoying in debug output.
1387                 &(crate_disambiguator.to_fingerprint().to_hex())[..4],
1388                 self.def_path(def_id).to_string_no_crate())
1389     }
1390
1391     pub fn metadata_encoding_version(self) -> Vec<u8> {
1392         self.cstore.metadata_encoding_version().to_vec()
1393     }
1394
1395     pub fn encode_metadata(self)-> EncodedMetadata {
1396         let _prof_timer = self.prof.generic_activity("generate_crate_metadata");
1397         self.cstore.encode_metadata(self)
1398     }
1399
1400     // Note that this is *untracked* and should only be used within the query
1401     // system if the result is otherwise tracked through queries
1402     pub fn cstore_as_any(self) -> &'tcx dyn Any {
1403         self.cstore.as_any()
1404     }
1405
1406     #[inline(always)]
1407     pub fn create_stable_hashing_context(self) -> StableHashingContext<'tcx> {
1408         let krate = self.gcx.hir_map.forest.untracked_krate();
1409
1410         StableHashingContext::new(self.sess,
1411                                   krate,
1412                                   self.hir().definitions(),
1413                                   &*self.cstore)
1414     }
1415
1416     // This method makes sure that we have a DepNode and a Fingerprint for
1417     // every upstream crate. It needs to be called once right after the tcx is
1418     // created.
1419     // With full-fledged red/green, the method will probably become unnecessary
1420     // as this will be done on-demand.
1421     pub fn allocate_metadata_dep_nodes(self) {
1422         // We cannot use the query versions of crates() and crate_hash(), since
1423         // those would need the DepNodes that we are allocating here.
1424         for cnum in self.cstore.crates_untracked() {
1425             let dep_node = DepNode::new(self, DepConstructor::CrateMetadata(cnum));
1426             let crate_hash = self.cstore.crate_hash_untracked(cnum);
1427             self.dep_graph.with_task(dep_node,
1428                                      self,
1429                                      crate_hash,
1430                                      |_, x| x, // No transformation needed
1431                                      dep_graph::hash_result,
1432             );
1433         }
1434     }
1435
1436     pub fn serialize_query_result_cache<E>(self,
1437                                            encoder: &mut E)
1438                                            -> Result<(), E::Error>
1439         where E: ty::codec::TyEncoder
1440     {
1441         self.queries.on_disk_cache.serialize(self, encoder)
1442     }
1443
1444     /// If `true`, we should use the MIR-based borrowck, but also
1445     /// fall back on the AST borrowck if the MIR-based one errors.
1446     pub fn migrate_borrowck(self) -> bool {
1447         self.borrowck_mode().migrate()
1448     }
1449
1450     /// If `true`, make MIR codegen for `match` emit a temp that holds a
1451     /// borrow of the input to the match expression.
1452     pub fn generate_borrow_of_any_match_input(&self) -> bool {
1453         self.emit_read_for_match()
1454     }
1455
1456     /// If `true`, make MIR codegen for `match` emit FakeRead
1457     /// statements (which simulate the maximal effect of executing the
1458     /// patterns in a match arm).
1459     pub fn emit_read_for_match(&self) -> bool {
1460         !self.sess.opts.debugging_opts.nll_dont_emit_read_for_match
1461     }
1462
1463     /// What mode(s) of borrowck should we run? AST? MIR? both?
1464     /// (Also considers the `#![feature(nll)]` setting.)
1465     pub fn borrowck_mode(&self) -> BorrowckMode {
1466         // Here are the main constraints we need to deal with:
1467         //
1468         // 1. An opts.borrowck_mode of `BorrowckMode::Migrate` is
1469         //    synonymous with no `-Z borrowck=...` flag at all.
1470         //
1471         // 2. We want to allow developers on the Nightly channel
1472         //    to opt back into the "hard error" mode for NLL,
1473         //    (which they can do via specifying `#![feature(nll)]`
1474         //    explicitly in their crate).
1475         //
1476         // So, this precedence list is how pnkfelix chose to work with
1477         // the above constraints:
1478         //
1479         // * `#![feature(nll)]` *always* means use NLL with hard
1480         //   errors. (To simplify the code here, it now even overrides
1481         //   a user's attempt to specify `-Z borrowck=compare`, which
1482         //   we arguably do not need anymore and should remove.)
1483         //
1484         // * Otherwise, if no `-Z borrowck=...` then use migrate mode
1485         //
1486         // * Otherwise, use the behavior requested via `-Z borrowck=...`
1487
1488         if self.features().nll { return BorrowckMode::Mir; }
1489
1490         self.sess.opts.borrowck_mode
1491     }
1492
1493     #[inline]
1494     pub fn local_crate_exports_generics(self) -> bool {
1495         debug_assert!(self.sess.opts.share_generics());
1496
1497         self.sess.crate_types.borrow().iter().any(|crate_type| {
1498             match crate_type {
1499                 CrateType::Executable |
1500                 CrateType::Staticlib  |
1501                 CrateType::ProcMacro  |
1502                 CrateType::Cdylib     => false,
1503
1504                 // FIXME rust-lang/rust#64319, rust-lang/rust#64872:
1505                 // We want to block export of generics from dylibs,
1506                 // but we must fix rust-lang/rust#65890 before we can
1507                 // do that robustly.
1508                 CrateType::Dylib      => true,
1509
1510                 CrateType::Rlib       => true,
1511             }
1512         })
1513     }
1514
1515     // Returns the `DefId` and the `BoundRegion` corresponding to the given region.
1516     pub fn is_suitable_region(&self, region: Region<'tcx>) -> Option<FreeRegionInfo> {
1517         let (suitable_region_binding_scope, bound_region) = match *region {
1518             ty::ReFree(ref free_region) => (free_region.scope, free_region.bound_region),
1519             ty::ReEarlyBound(ref ebr) => (
1520                 self.parent(ebr.def_id).unwrap(),
1521                 ty::BoundRegion::BrNamed(ebr.def_id, ebr.name),
1522             ),
1523             _ => return None, // not a free region
1524         };
1525
1526         let hir_id = self.hir()
1527             .as_local_hir_id(suitable_region_binding_scope)
1528             .unwrap();
1529         let is_impl_item = match self.hir().find(hir_id) {
1530             Some(Node::Item(..)) | Some(Node::TraitItem(..)) => false,
1531             Some(Node::ImplItem(..)) => {
1532                 self.is_bound_region_in_impl_item(suitable_region_binding_scope)
1533             }
1534             _ => return None,
1535         };
1536
1537         return Some(FreeRegionInfo {
1538             def_id: suitable_region_binding_scope,
1539             boundregion: bound_region,
1540             is_impl_item,
1541         });
1542     }
1543
1544     pub fn return_type_impl_trait(
1545         &self,
1546         scope_def_id: DefId,
1547     ) -> Option<(Ty<'tcx>, Span)> {
1548         // HACK: `type_of_def_id()` will fail on these (#55796), so return `None`.
1549         let hir_id = self.hir().as_local_hir_id(scope_def_id).unwrap();
1550         match self.hir().get(hir_id) {
1551             Node::Item(item) => {
1552                 match item.kind {
1553                     ItemKind::Fn(..) => { /* `type_of_def_id()` will work */ }
1554                     _ => {
1555                         return None;
1556                     }
1557                 }
1558             }
1559             _ => { /* `type_of_def_id()` will work or panic */ }
1560         }
1561
1562         let ret_ty = self.type_of(scope_def_id);
1563         match ret_ty.kind {
1564             ty::FnDef(_, _) => {
1565                 let sig = ret_ty.fn_sig(*self);
1566                 let output = self.erase_late_bound_regions(&sig.output());
1567                 if output.is_impl_trait() {
1568                     let fn_decl = self.hir().fn_decl_by_hir_id(hir_id).unwrap();
1569                     Some((output, fn_decl.output.span()))
1570                 } else {
1571                     None
1572                 }
1573             }
1574             _ => None
1575         }
1576     }
1577
1578     // Checks if the bound region is in Impl Item.
1579     pub fn is_bound_region_in_impl_item(
1580         &self,
1581         suitable_region_binding_scope: DefId,
1582     ) -> bool {
1583         let container_id = self.associated_item(suitable_region_binding_scope)
1584             .container
1585             .id();
1586         if self.impl_trait_ref(container_id).is_some() {
1587             // For now, we do not try to target impls of traits. This is
1588             // because this message is going to suggest that the user
1589             // change the fn signature, but they may not be free to do so,
1590             // since the signature must match the trait.
1591             //
1592             // FIXME(#42706) -- in some cases, we could do better here.
1593             return true;
1594         }
1595         false
1596     }
1597
1598     /// Determines whether identifiers in the assembly have strict naming rules.
1599     /// Currently, only NVPTX* targets need it.
1600     pub fn has_strict_asm_symbol_naming(&self) -> bool {
1601         self.sess.target.target.arch.contains("nvptx")
1602     }
1603
1604     /// Returns `&'static core::panic::Location<'static>`.
1605     pub fn caller_location_ty(&self) -> Ty<'tcx> {
1606         self.mk_imm_ref(
1607             self.lifetimes.re_static,
1608             self.type_of(self.require_lang_item(PanicLocationLangItem, None))
1609                 .subst(*self, self.mk_substs([self.lifetimes.re_static.into()].iter())),
1610         )
1611     }
1612 }
1613
1614 impl<'tcx> GlobalCtxt<'tcx> {
1615     /// Calls the closure with a local `TyCtxt` using the given arena.
1616     /// `interners` is a slot passed so we can create a CtxtInterners
1617     /// with the same lifetime as `arena`.
1618     pub fn enter_local<F, R>(&'tcx self, f: F) -> R
1619     where
1620         F: FnOnce(TyCtxt<'tcx>) -> R,
1621     {
1622         let tcx = TyCtxt {
1623             gcx: self,
1624         };
1625         ty::tls::with_related_context(tcx, |icx| {
1626             let new_icx = ty::tls::ImplicitCtxt {
1627                 tcx,
1628                 query: icx.query.clone(),
1629                 diagnostics: icx.diagnostics,
1630                 layout_depth: icx.layout_depth,
1631                 task_deps: icx.task_deps,
1632             };
1633             ty::tls::enter_context(&new_icx, |_| {
1634                 f(tcx)
1635             })
1636         })
1637     }
1638 }
1639
1640 /// A trait implemented for all `X<'a>` types that can be safely and
1641 /// efficiently converted to `X<'tcx>` as long as they are part of the
1642 /// provided `TyCtxt<'tcx>`.
1643 /// This can be done, for example, for `Ty<'tcx>` or `SubstsRef<'tcx>`
1644 /// by looking them up in their respective interners.
1645 ///
1646 /// However, this is still not the best implementation as it does
1647 /// need to compare the components, even for interned values.
1648 /// It would be more efficient if `TypedArena` provided a way to
1649 /// determine whether the address is in the allocated range.
1650 ///
1651 /// `None` is returned if the value or one of the components is not part
1652 /// of the provided context.
1653 /// For `Ty`, `None` can be returned if either the type interner doesn't
1654 /// contain the `TyKind` key or if the address of the interned
1655 /// pointer differs. The latter case is possible if a primitive type,
1656 /// e.g., `()` or `u8`, was interned in a different context.
1657 pub trait Lift<'tcx>: fmt::Debug {
1658     type Lifted: fmt::Debug + 'tcx;
1659     fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted>;
1660 }
1661
1662 macro_rules! nop_lift {
1663     ($ty:ty => $lifted:ty) => {
1664         impl<'a, 'tcx> Lift<'tcx> for $ty {
1665                     type Lifted = $lifted;
1666                     fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
1667                         if tcx.interners.arena.in_arena(*self as *const _) {
1668                             Some(unsafe { mem::transmute(*self) })
1669                         } else {
1670                             None
1671                         }
1672                     }
1673                 }
1674     };
1675 }
1676
1677 macro_rules! nop_list_lift {
1678     ($ty:ty => $lifted:ty) => {
1679         impl<'a, 'tcx> Lift<'tcx> for &'a List<$ty> {
1680                     type Lifted = &'tcx List<$lifted>;
1681                     fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
1682                         if self.is_empty() {
1683                             return Some(List::empty());
1684                         }
1685                         if tcx.interners.arena.in_arena(*self as *const _) {
1686                             Some(unsafe { mem::transmute(*self) })
1687                         } else {
1688                             None
1689                         }
1690                     }
1691                 }
1692     };
1693 }
1694
1695 nop_lift!{Ty<'a> => Ty<'tcx>}
1696 nop_lift!{Region<'a> => Region<'tcx>}
1697 nop_lift!{Goal<'a> => Goal<'tcx>}
1698 nop_lift!{&'a Const<'a> => &'tcx Const<'tcx>}
1699
1700 nop_list_lift!{Goal<'a> => Goal<'tcx>}
1701 nop_list_lift!{Clause<'a> => Clause<'tcx>}
1702 nop_list_lift!{Ty<'a> => Ty<'tcx>}
1703 nop_list_lift!{ExistentialPredicate<'a> => ExistentialPredicate<'tcx>}
1704 nop_list_lift!{Predicate<'a> => Predicate<'tcx>}
1705 nop_list_lift!{CanonicalVarInfo => CanonicalVarInfo}
1706 nop_list_lift!{ProjectionKind => ProjectionKind}
1707
1708 // This is the impl for `&'a InternalSubsts<'a>`.
1709 nop_list_lift!{GenericArg<'a> => GenericArg<'tcx>}
1710
1711 pub mod tls {
1712     use super::{GlobalCtxt, TyCtxt, ptr_eq};
1713
1714     use std::fmt;
1715     use std::mem;
1716     use syntax_pos;
1717     use crate::ty::query;
1718     use errors::{Diagnostic, TRACK_DIAGNOSTICS};
1719     use rustc_data_structures::OnDrop;
1720     use rustc_data_structures::sync::{self, Lrc, Lock};
1721     use rustc_data_structures::thin_vec::ThinVec;
1722     use crate::dep_graph::TaskDeps;
1723
1724     #[cfg(not(parallel_compiler))]
1725     use std::cell::Cell;
1726
1727     #[cfg(parallel_compiler)]
1728     use rustc_rayon_core as rayon_core;
1729
1730     /// This is the implicit state of rustc. It contains the current
1731     /// `TyCtxt` and query. It is updated when creating a local interner or
1732     /// executing a new query. Whenever there's a `TyCtxt` value available
1733     /// you should also have access to an `ImplicitCtxt` through the functions
1734     /// in this module.
1735     #[derive(Clone)]
1736     pub struct ImplicitCtxt<'a, 'tcx> {
1737         /// The current `TyCtxt`. Initially created by `enter_global` and updated
1738         /// by `enter_local` with a new local interner.
1739         pub tcx: TyCtxt<'tcx>,
1740
1741         /// The current query job, if any. This is updated by `JobOwner::start` in
1742         /// `ty::query::plumbing` when executing a query.
1743         pub query: Option<Lrc<query::QueryJob<'tcx>>>,
1744
1745         /// Where to store diagnostics for the current query job, if any.
1746         /// This is updated by `JobOwner::start` in `ty::query::plumbing` when executing a query.
1747         pub diagnostics: Option<&'a Lock<ThinVec<Diagnostic>>>,
1748
1749         /// Used to prevent layout from recursing too deeply.
1750         pub layout_depth: usize,
1751
1752         /// The current dep graph task. This is used to add dependencies to queries
1753         /// when executing them.
1754         pub task_deps: Option<&'a Lock<TaskDeps>>,
1755     }
1756
1757     /// Sets Rayon's thread-local variable, which is preserved for Rayon jobs
1758     /// to `value` during the call to `f`. It is restored to its previous value after.
1759     /// This is used to set the pointer to the new `ImplicitCtxt`.
1760     #[cfg(parallel_compiler)]
1761     #[inline]
1762     fn set_tlv<F: FnOnce() -> R, R>(value: usize, f: F) -> R {
1763         rayon_core::tlv::with(value, f)
1764     }
1765
1766     /// Gets Rayon's thread-local variable, which is preserved for Rayon jobs.
1767     /// This is used to get the pointer to the current `ImplicitCtxt`.
1768     #[cfg(parallel_compiler)]
1769     #[inline]
1770     fn get_tlv() -> usize {
1771         rayon_core::tlv::get()
1772     }
1773
1774     #[cfg(not(parallel_compiler))]
1775     thread_local! {
1776         /// A thread local variable that stores a pointer to the current `ImplicitCtxt`.
1777         static TLV: Cell<usize> = Cell::new(0);
1778     }
1779
1780     /// Sets TLV to `value` during the call to `f`.
1781     /// It is restored to its previous value after.
1782     /// This is used to set the pointer to the new `ImplicitCtxt`.
1783     #[cfg(not(parallel_compiler))]
1784     #[inline]
1785     fn set_tlv<F: FnOnce() -> R, R>(value: usize, f: F) -> R {
1786         let old = get_tlv();
1787         let _reset = OnDrop(move || TLV.with(|tlv| tlv.set(old)));
1788         TLV.with(|tlv| tlv.set(value));
1789         f()
1790     }
1791
1792     /// Gets the pointer to the current `ImplicitCtxt`.
1793     #[cfg(not(parallel_compiler))]
1794     fn get_tlv() -> usize {
1795         TLV.with(|tlv| tlv.get())
1796     }
1797
1798     /// This is a callback from libsyntax as it cannot access the implicit state
1799     /// in librustc otherwise.
1800     fn span_debug(span: syntax_pos::Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1801         with_opt(|tcx| {
1802             if let Some(tcx) = tcx {
1803                 write!(f, "{}", tcx.sess.source_map().span_to_string(span))
1804             } else {
1805                 syntax_pos::default_span_debug(span, f)
1806             }
1807         })
1808     }
1809
1810     /// This is a callback from libsyntax as it cannot access the implicit state
1811     /// in librustc otherwise. It is used to when diagnostic messages are
1812     /// emitted and stores them in the current query, if there is one.
1813     fn track_diagnostic(diagnostic: &Diagnostic) {
1814         with_context_opt(|icx| {
1815             if let Some(icx) = icx {
1816                 if let Some(ref diagnostics) = icx.diagnostics {
1817                     let mut diagnostics = diagnostics.lock();
1818                     diagnostics.extend(Some(diagnostic.clone()));
1819                 }
1820             }
1821         })
1822     }
1823
1824     /// Sets up the callbacks from libsyntax on the current thread.
1825     pub fn with_thread_locals<F, R>(f: F) -> R
1826         where F: FnOnce() -> R
1827     {
1828         syntax_pos::SPAN_DEBUG.with(|span_dbg| {
1829             let original_span_debug = span_dbg.get();
1830             span_dbg.set(span_debug);
1831
1832             let _on_drop = OnDrop(move || {
1833                 span_dbg.set(original_span_debug);
1834             });
1835
1836             TRACK_DIAGNOSTICS.with(|current| {
1837                 let original = current.get();
1838                 current.set(track_diagnostic);
1839
1840                 let _on_drop = OnDrop(move || {
1841                     current.set(original);
1842                 });
1843
1844                 f()
1845             })
1846         })
1847     }
1848
1849     /// Sets `context` as the new current `ImplicitCtxt` for the duration of the function `f`.
1850     #[inline]
1851     pub fn enter_context<'a, 'tcx, F, R>(context: &ImplicitCtxt<'a, 'tcx>, f: F) -> R
1852     where
1853         F: FnOnce(&ImplicitCtxt<'a, 'tcx>) -> R,
1854     {
1855         set_tlv(context as *const _ as usize, || {
1856             f(&context)
1857         })
1858     }
1859
1860     /// Enters `GlobalCtxt` by setting up libsyntax callbacks and
1861     /// creating a initial `TyCtxt` and `ImplicitCtxt`.
1862     /// This happens once per rustc session and `TyCtxt`s only exists
1863     /// inside the `f` function.
1864     pub fn enter_global<'tcx, F, R>(gcx: &'tcx GlobalCtxt<'tcx>, f: F) -> R
1865     where
1866         F: FnOnce(TyCtxt<'tcx>) -> R,
1867     {
1868         // Update `GCX_PTR` to indicate there's a `GlobalCtxt` available.
1869         GCX_PTR.with(|lock| {
1870             *lock.lock() = gcx as *const _ as usize;
1871         });
1872         // Set `GCX_PTR` back to 0 when we exit.
1873         let _on_drop = OnDrop(move || {
1874             GCX_PTR.with(|lock| *lock.lock() = 0);
1875         });
1876
1877         let tcx = TyCtxt {
1878             gcx,
1879         };
1880         let icx = ImplicitCtxt {
1881             tcx,
1882             query: None,
1883             diagnostics: None,
1884             layout_depth: 0,
1885             task_deps: None,
1886         };
1887         enter_context(&icx, |_| {
1888             f(tcx)
1889         })
1890     }
1891
1892     scoped_thread_local! {
1893         /// Stores a pointer to the `GlobalCtxt` if one is available.
1894         /// This is used to access the `GlobalCtxt` in the deadlock handler given to Rayon.
1895         pub static GCX_PTR: Lock<usize>
1896     }
1897
1898     /// Creates a `TyCtxt` and `ImplicitCtxt` based on the `GCX_PTR` thread local.
1899     /// This is used in the deadlock handler.
1900     pub unsafe fn with_global<F, R>(f: F) -> R
1901     where
1902         F: for<'tcx> FnOnce(TyCtxt<'tcx>) -> R,
1903     {
1904         let gcx = GCX_PTR.with(|lock| *lock.lock());
1905         assert!(gcx != 0);
1906         let gcx = &*(gcx as *const GlobalCtxt<'_>);
1907         let tcx = TyCtxt {
1908             gcx,
1909         };
1910         let icx = ImplicitCtxt {
1911             query: None,
1912             diagnostics: None,
1913             tcx,
1914             layout_depth: 0,
1915             task_deps: None,
1916         };
1917         enter_context(&icx, |_| f(tcx))
1918     }
1919
1920     /// Allows access to the current `ImplicitCtxt` in a closure if one is available.
1921     #[inline]
1922     pub fn with_context_opt<F, R>(f: F) -> R
1923     where
1924         F: for<'a, 'tcx> FnOnce(Option<&ImplicitCtxt<'a, 'tcx>>) -> R,
1925     {
1926         let context = get_tlv();
1927         if context == 0 {
1928             f(None)
1929         } else {
1930             // We could get a `ImplicitCtxt` pointer from another thread.
1931             // Ensure that `ImplicitCtxt` is `Sync`.
1932             sync::assert_sync::<ImplicitCtxt<'_, '_>>();
1933
1934             unsafe { f(Some(&*(context as *const ImplicitCtxt<'_, '_>))) }
1935         }
1936     }
1937
1938     /// Allows access to the current `ImplicitCtxt`.
1939     /// Panics if there is no `ImplicitCtxt` available.
1940     #[inline]
1941     pub fn with_context<F, R>(f: F) -> R
1942     where
1943         F: for<'a, 'tcx> FnOnce(&ImplicitCtxt<'a, 'tcx>) -> R,
1944     {
1945         with_context_opt(|opt_context| f(opt_context.expect("no ImplicitCtxt stored in tls")))
1946     }
1947
1948     /// Allows access to the current `ImplicitCtxt` whose tcx field has the same global
1949     /// interner as the tcx argument passed in. This means the closure is given an `ImplicitCtxt`
1950     /// with the same `'tcx` lifetime as the `TyCtxt` passed in.
1951     /// This will panic if you pass it a `TyCtxt` which has a different global interner from
1952     /// the current `ImplicitCtxt`'s `tcx` field.
1953     #[inline]
1954     pub fn with_related_context<'tcx, F, R>(tcx: TyCtxt<'tcx>, f: F) -> R
1955     where
1956         F: FnOnce(&ImplicitCtxt<'_, 'tcx>) -> R,
1957     {
1958         with_context(|context| {
1959             unsafe {
1960                 assert!(ptr_eq(context.tcx.gcx, tcx.gcx));
1961                 let context: &ImplicitCtxt<'_, '_> = mem::transmute(context);
1962                 f(context)
1963             }
1964         })
1965     }
1966
1967     /// Allows access to the `TyCtxt` in the current `ImplicitCtxt`.
1968     /// Panics if there is no `ImplicitCtxt` available.
1969     #[inline]
1970     pub fn with<F, R>(f: F) -> R
1971     where
1972         F: for<'tcx> FnOnce(TyCtxt<'tcx>) -> R,
1973     {
1974         with_context(|context| f(context.tcx))
1975     }
1976
1977     /// Allows access to the `TyCtxt` in the current `ImplicitCtxt`.
1978     /// The closure is passed None if there is no `ImplicitCtxt` available.
1979     #[inline]
1980     pub fn with_opt<F, R>(f: F) -> R
1981     where
1982         F: for<'tcx> FnOnce(Option<TyCtxt<'tcx>>) -> R,
1983     {
1984         with_context_opt(|opt_context| f(opt_context.map(|context| context.tcx)))
1985     }
1986 }
1987
1988 macro_rules! sty_debug_print {
1989     ($ctxt: expr, $($variant: ident),*) => {{
1990         // Curious inner module to allow variant names to be used as
1991         // variable names.
1992         #[allow(non_snake_case)]
1993         mod inner {
1994             use crate::ty::{self, TyCtxt};
1995             use crate::ty::context::Interned;
1996
1997             #[derive(Copy, Clone)]
1998             struct DebugStat {
1999                 total: usize,
2000                 lt_infer: usize,
2001                 ty_infer: usize,
2002                 ct_infer: usize,
2003                 all_infer: usize,
2004             }
2005
2006             pub fn go(tcx: TyCtxt<'_>) {
2007                 let mut total = DebugStat {
2008                     total: 0,
2009                     lt_infer: 0,
2010                     ty_infer: 0,
2011                     ct_infer: 0,
2012                     all_infer: 0,
2013                 };
2014                 $(let mut $variant = total;)*
2015
2016                 let shards = tcx.interners.type_.lock_shards();
2017                 let types = shards.iter().flat_map(|shard| shard.keys());
2018                 for &Interned(t) in types {
2019                     let variant = match t.kind {
2020                         ty::Bool | ty::Char | ty::Int(..) | ty::Uint(..) |
2021                             ty::Float(..) | ty::Str | ty::Never => continue,
2022                         ty::Error => /* unimportant */ continue,
2023                         $(ty::$variant(..) => &mut $variant,)*
2024                     };
2025                     let lt = t.flags.intersects(ty::TypeFlags::HAS_RE_INFER);
2026                     let ty = t.flags.intersects(ty::TypeFlags::HAS_TY_INFER);
2027                     let ct = t.flags.intersects(ty::TypeFlags::HAS_CT_INFER);
2028
2029                     variant.total += 1;
2030                     total.total += 1;
2031                     if lt { total.lt_infer += 1; variant.lt_infer += 1 }
2032                     if ty { total.ty_infer += 1; variant.ty_infer += 1 }
2033                     if ct { total.ct_infer += 1; variant.ct_infer += 1 }
2034                     if lt && ty && ct { total.all_infer += 1; variant.all_infer += 1 }
2035                 }
2036                 println!("Ty interner             total           ty lt ct all");
2037                 $(println!("    {:18}: {uses:6} {usespc:4.1}%, \
2038                             {ty:4.1}% {lt:5.1}% {ct:4.1}% {all:4.1}%",
2039                     stringify!($variant),
2040                     uses = $variant.total,
2041                     usespc = $variant.total as f64 * 100.0 / total.total as f64,
2042                     ty = $variant.ty_infer as f64 * 100.0  / total.total as f64,
2043                     lt = $variant.lt_infer as f64 * 100.0  / total.total as f64,
2044                     ct = $variant.ct_infer as f64 * 100.0  / total.total as f64,
2045                     all = $variant.all_infer as f64 * 100.0  / total.total as f64);
2046                 )*
2047                 println!("                  total {uses:6}        \
2048                           {ty:4.1}% {lt:5.1}% {ct:4.1}% {all:4.1}%",
2049                     uses = total.total,
2050                     ty = total.ty_infer as f64 * 100.0  / total.total as f64,
2051                     lt = total.lt_infer as f64 * 100.0  / total.total as f64,
2052                     ct = total.ct_infer as f64 * 100.0  / total.total as f64,
2053                     all = total.all_infer as f64 * 100.0  / total.total as f64)
2054             }
2055         }
2056
2057         inner::go($ctxt)
2058     }}
2059 }
2060
2061 impl<'tcx> TyCtxt<'tcx> {
2062     pub fn print_debug_stats(self) {
2063         sty_debug_print!(
2064             self,
2065             Adt, Array, Slice, RawPtr, Ref, FnDef, FnPtr, Placeholder,
2066             Generator, GeneratorWitness, Dynamic, Closure, Tuple, Bound,
2067             Param, Infer, UnnormalizedProjection, Projection, Opaque, Foreign);
2068
2069         println!("InternalSubsts interner: #{}", self.interners.substs.len());
2070         println!("Region interner: #{}", self.interners.region.len());
2071         println!("Stability interner: #{}", self.stability_interner.len());
2072         println!("Const Stability interner: #{}", self.const_stability_interner.len());
2073         println!("Allocation interner: #{}", self.allocation_interner.len());
2074         println!("Layout interner: #{}", self.layout_interner.len());
2075     }
2076 }
2077
2078
2079 /// An entry in an interner.
2080 struct Interned<'tcx, T: ?Sized>(&'tcx T);
2081
2082 impl<'tcx, T: 'tcx+?Sized> Clone for Interned<'tcx, T> {
2083     fn clone(&self) -> Self {
2084         Interned(self.0)
2085     }
2086 }
2087 impl<'tcx, T: 'tcx+?Sized> Copy for Interned<'tcx, T> {}
2088
2089 // N.B., an `Interned<Ty>` compares and hashes as a `TyKind`.
2090 impl<'tcx> PartialEq for Interned<'tcx, TyS<'tcx>> {
2091     fn eq(&self, other: &Interned<'tcx, TyS<'tcx>>) -> bool {
2092         self.0.kind == other.0.kind
2093     }
2094 }
2095
2096 impl<'tcx> Eq for Interned<'tcx, TyS<'tcx>> {}
2097
2098 impl<'tcx> Hash for Interned<'tcx, TyS<'tcx>> {
2099     fn hash<H: Hasher>(&self, s: &mut H) {
2100         self.0.kind.hash(s)
2101     }
2102 }
2103
2104 #[allow(rustc::usage_of_ty_tykind)]
2105 impl<'tcx> Borrow<TyKind<'tcx>> for Interned<'tcx, TyS<'tcx>> {
2106     fn borrow<'a>(&'a self) -> &'a TyKind<'tcx> {
2107         &self.0.kind
2108     }
2109 }
2110
2111 // N.B., an `Interned<List<T>>` compares and hashes as its elements.
2112 impl<'tcx, T: PartialEq> PartialEq for Interned<'tcx, List<T>> {
2113     fn eq(&self, other: &Interned<'tcx, List<T>>) -> bool {
2114         self.0[..] == other.0[..]
2115     }
2116 }
2117
2118 impl<'tcx, T: Eq> Eq for Interned<'tcx, List<T>> {}
2119
2120 impl<'tcx, T: Hash> Hash for Interned<'tcx, List<T>> {
2121     fn hash<H: Hasher>(&self, s: &mut H) {
2122         self.0[..].hash(s)
2123     }
2124 }
2125
2126 impl<'tcx> Borrow<[Ty<'tcx>]> for Interned<'tcx, List<Ty<'tcx>>> {
2127     fn borrow<'a>(&'a self) -> &'a [Ty<'tcx>] {
2128         &self.0[..]
2129     }
2130 }
2131
2132 impl<'tcx> Borrow<[CanonicalVarInfo]> for Interned<'tcx, List<CanonicalVarInfo>> {
2133     fn borrow(&self) -> &[CanonicalVarInfo] {
2134         &self.0[..]
2135     }
2136 }
2137
2138 impl<'tcx> Borrow<[GenericArg<'tcx>]> for Interned<'tcx, InternalSubsts<'tcx>> {
2139     fn borrow<'a>(&'a self) -> &'a [GenericArg<'tcx>] {
2140         &self.0[..]
2141     }
2142 }
2143
2144 impl<'tcx> Borrow<[ProjectionKind]>
2145     for Interned<'tcx, List<ProjectionKind>> {
2146     fn borrow(&self) -> &[ProjectionKind] {
2147         &self.0[..]
2148     }
2149 }
2150
2151 impl<'tcx> Borrow<[PlaceElem<'tcx>]>
2152     for Interned<'tcx, List<PlaceElem<'tcx>>> {
2153     fn borrow(&self) -> &[PlaceElem<'tcx>] {
2154         &self.0[..]
2155     }
2156 }
2157
2158 impl<'tcx> Borrow<RegionKind> for Interned<'tcx, RegionKind> {
2159     fn borrow(&self) -> &RegionKind {
2160         &self.0
2161     }
2162 }
2163
2164 impl<'tcx> Borrow<GoalKind<'tcx>> for Interned<'tcx, GoalKind<'tcx>> {
2165     fn borrow<'a>(&'a self) -> &'a GoalKind<'tcx> {
2166         &self.0
2167     }
2168 }
2169
2170 impl<'tcx> Borrow<[ExistentialPredicate<'tcx>]>
2171     for Interned<'tcx, List<ExistentialPredicate<'tcx>>>
2172 {
2173     fn borrow<'a>(&'a self) -> &'a [ExistentialPredicate<'tcx>] {
2174         &self.0[..]
2175     }
2176 }
2177
2178 impl<'tcx> Borrow<[Predicate<'tcx>]> for Interned<'tcx, List<Predicate<'tcx>>> {
2179     fn borrow<'a>(&'a self) -> &'a [Predicate<'tcx>] {
2180         &self.0[..]
2181     }
2182 }
2183
2184 impl<'tcx> Borrow<Const<'tcx>> for Interned<'tcx, Const<'tcx>> {
2185     fn borrow<'a>(&'a self) -> &'a Const<'tcx> {
2186         &self.0
2187     }
2188 }
2189
2190 impl<'tcx> Borrow<[Clause<'tcx>]> for Interned<'tcx, List<Clause<'tcx>>> {
2191     fn borrow<'a>(&'a self) -> &'a [Clause<'tcx>] {
2192         &self.0[..]
2193     }
2194 }
2195
2196 impl<'tcx> Borrow<[Goal<'tcx>]> for Interned<'tcx, List<Goal<'tcx>>> {
2197     fn borrow<'a>(&'a self) -> &'a [Goal<'tcx>] {
2198         &self.0[..]
2199     }
2200 }
2201
2202 macro_rules! direct_interners {
2203     ($($name:ident: $method:ident($ty:ty)),+) => {
2204         $(impl<'tcx> PartialEq for Interned<'tcx, $ty> {
2205             fn eq(&self, other: &Self) -> bool {
2206                 self.0 == other.0
2207             }
2208         }
2209
2210         impl<'tcx> Eq for Interned<'tcx, $ty> {}
2211
2212         impl<'tcx> Hash for Interned<'tcx, $ty> {
2213             fn hash<H: Hasher>(&self, s: &mut H) {
2214                 self.0.hash(s)
2215             }
2216         }
2217
2218         impl<'tcx> TyCtxt<'tcx> {
2219             pub fn $method(self, v: $ty) -> &'tcx $ty {
2220                 self.interners.$name.intern_ref(&v, || {
2221                     Interned(self.interners.arena.alloc(v))
2222                 }).0
2223             }
2224         })+
2225     }
2226 }
2227
2228 pub fn keep_local<'tcx, T: ty::TypeFoldable<'tcx>>(x: &T) -> bool {
2229     x.has_type_flags(ty::TypeFlags::KEEP_IN_LOCAL_TCX)
2230 }
2231
2232 direct_interners!(
2233     region: mk_region(RegionKind),
2234     goal: mk_goal(GoalKind<'tcx>),
2235     const_: mk_const(Const<'tcx>)
2236 );
2237
2238 macro_rules! slice_interners {
2239     ($($field:ident: $method:ident($ty:ty)),+) => (
2240         $(impl<'tcx> TyCtxt<'tcx> {
2241             pub fn $method(self, v: &[$ty]) -> &'tcx List<$ty> {
2242                 self.interners.$field.intern_ref(v, || {
2243                     Interned(List::from_arena(&self.interners.arena, v))
2244                 }).0
2245             }
2246         })+
2247     );
2248 }
2249
2250 slice_interners!(
2251     type_list: _intern_type_list(Ty<'tcx>),
2252     substs: _intern_substs(GenericArg<'tcx>),
2253     canonical_var_infos: _intern_canonical_var_infos(CanonicalVarInfo),
2254     existential_predicates: _intern_existential_predicates(ExistentialPredicate<'tcx>),
2255     predicates: _intern_predicates(Predicate<'tcx>),
2256     clauses: _intern_clauses(Clause<'tcx>),
2257     goal_list: _intern_goals(Goal<'tcx>),
2258     projs: _intern_projs(ProjectionKind),
2259     place_elems: _intern_place_elems(PlaceElem<'tcx>)
2260 );
2261
2262 impl<'tcx> TyCtxt<'tcx> {
2263     /// Given a `fn` type, returns an equivalent `unsafe fn` type;
2264     /// that is, a `fn` type that is equivalent in every way for being
2265     /// unsafe.
2266     pub fn safe_to_unsafe_fn_ty(self, sig: PolyFnSig<'tcx>) -> Ty<'tcx> {
2267         assert_eq!(sig.unsafety(), hir::Unsafety::Normal);
2268         self.mk_fn_ptr(sig.map_bound(|sig| ty::FnSig {
2269             unsafety: hir::Unsafety::Unsafe,
2270             ..sig
2271         }))
2272     }
2273
2274     /// Given a closure signature `sig`, returns an equivalent `fn`
2275     /// type with the same signature. Detuples and so forth -- so
2276     /// e.g., if we have a sig with `Fn<(u32, i32)>` then you would get
2277     /// a `fn(u32, i32)`.
2278     /// `unsafety` determines the unsafety of the `fn` type. If you pass
2279     /// `hir::Unsafety::Unsafe` in the previous example, then you would get
2280     /// an `unsafe fn (u32, i32)`.
2281     /// It cannot convert a closure that requires unsafe.
2282     pub fn coerce_closure_fn_ty(self, sig: PolyFnSig<'tcx>, unsafety: hir::Unsafety) -> Ty<'tcx> {
2283         let converted_sig = sig.map_bound(|s| {
2284             let params_iter = match s.inputs()[0].kind {
2285                 ty::Tuple(params) => {
2286                     params.into_iter().map(|k| k.expect_ty())
2287                 }
2288                 _ => bug!(),
2289             };
2290             self.mk_fn_sig(
2291                 params_iter,
2292                 s.output(),
2293                 s.c_variadic,
2294                 unsafety,
2295                 abi::Abi::Rust,
2296             )
2297         });
2298
2299         self.mk_fn_ptr(converted_sig)
2300     }
2301
2302     #[allow(rustc::usage_of_ty_tykind)]
2303     #[inline]
2304     pub fn mk_ty(&self, st: TyKind<'tcx>) -> Ty<'tcx> {
2305         self.interners.intern_ty(st)
2306     }
2307
2308     pub fn mk_mach_int(self, tm: ast::IntTy) -> Ty<'tcx> {
2309         match tm {
2310             ast::IntTy::Isize   => self.types.isize,
2311             ast::IntTy::I8   => self.types.i8,
2312             ast::IntTy::I16  => self.types.i16,
2313             ast::IntTy::I32  => self.types.i32,
2314             ast::IntTy::I64  => self.types.i64,
2315             ast::IntTy::I128  => self.types.i128,
2316         }
2317     }
2318
2319     pub fn mk_mach_uint(self, tm: ast::UintTy) -> Ty<'tcx> {
2320         match tm {
2321             ast::UintTy::Usize   => self.types.usize,
2322             ast::UintTy::U8   => self.types.u8,
2323             ast::UintTy::U16  => self.types.u16,
2324             ast::UintTy::U32  => self.types.u32,
2325             ast::UintTy::U64  => self.types.u64,
2326             ast::UintTy::U128  => self.types.u128,
2327         }
2328     }
2329
2330     pub fn mk_mach_float(self, tm: ast::FloatTy) -> Ty<'tcx> {
2331         match tm {
2332             ast::FloatTy::F32  => self.types.f32,
2333             ast::FloatTy::F64  => self.types.f64,
2334         }
2335     }
2336
2337     #[inline]
2338     pub fn mk_str(self) -> Ty<'tcx> {
2339         self.mk_ty(Str)
2340     }
2341
2342     #[inline]
2343     pub fn mk_static_str(self) -> Ty<'tcx> {
2344         self.mk_imm_ref(self.lifetimes.re_static, self.mk_str())
2345     }
2346
2347     #[inline]
2348     pub fn mk_adt(self, def: &'tcx AdtDef, substs: SubstsRef<'tcx>) -> Ty<'tcx> {
2349         // Take a copy of substs so that we own the vectors inside.
2350         self.mk_ty(Adt(def, substs))
2351     }
2352
2353     #[inline]
2354     pub fn mk_foreign(self, def_id: DefId) -> Ty<'tcx> {
2355         self.mk_ty(Foreign(def_id))
2356     }
2357
2358     fn mk_generic_adt(self, wrapper_def_id: DefId, ty_param: Ty<'tcx>) -> Ty<'tcx> {
2359         let adt_def = self.adt_def(wrapper_def_id);
2360         let substs = InternalSubsts::for_item(self, wrapper_def_id, |param, substs| {
2361             match param.kind {
2362                 GenericParamDefKind::Lifetime |
2363                 GenericParamDefKind::Const => {
2364                     bug!()
2365                 }
2366                 GenericParamDefKind::Type { has_default, .. } => {
2367                     if param.index == 0 {
2368                         ty_param.into()
2369                     } else {
2370                         assert!(has_default);
2371                         self.type_of(param.def_id).subst(self, substs).into()
2372                     }
2373                 }
2374             }
2375         });
2376         self.mk_ty(Adt(adt_def, substs))
2377     }
2378
2379     #[inline]
2380     pub fn mk_box(self, ty: Ty<'tcx>) -> Ty<'tcx> {
2381         let def_id = self.require_lang_item(lang_items::OwnedBoxLangItem, None);
2382         self.mk_generic_adt(def_id, ty)
2383     }
2384
2385     #[inline]
2386     pub fn mk_lang_item(self, ty: Ty<'tcx>, item: lang_items::LangItem)  -> Option<Ty<'tcx>> {
2387         let def_id = self.lang_items().require(item).ok()?;
2388         Some(self.mk_generic_adt(def_id, ty))
2389     }
2390
2391     #[inline]
2392     pub fn mk_maybe_uninit(self, ty: Ty<'tcx>) -> Ty<'tcx> {
2393         let def_id = self.require_lang_item(lang_items::MaybeUninitLangItem, None);
2394         self.mk_generic_adt(def_id, ty)
2395     }
2396
2397     #[inline]
2398     pub fn mk_ptr(self, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
2399         self.mk_ty(RawPtr(tm))
2400     }
2401
2402     #[inline]
2403     pub fn mk_ref(self, r: Region<'tcx>, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
2404         self.mk_ty(Ref(r, tm.ty, tm.mutbl))
2405     }
2406
2407     #[inline]
2408     pub fn mk_mut_ref(self, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
2409         self.mk_ref(r, TypeAndMut {ty: ty, mutbl: hir::Mutability::Mutable})
2410     }
2411
2412     #[inline]
2413     pub fn mk_imm_ref(self, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
2414         self.mk_ref(r, TypeAndMut {ty: ty, mutbl: hir::Mutability::Immutable})
2415     }
2416
2417     #[inline]
2418     pub fn mk_mut_ptr(self, ty: Ty<'tcx>) -> Ty<'tcx> {
2419         self.mk_ptr(TypeAndMut {ty: ty, mutbl: hir::Mutability::Mutable})
2420     }
2421
2422     #[inline]
2423     pub fn mk_imm_ptr(self, ty: Ty<'tcx>) -> Ty<'tcx> {
2424         self.mk_ptr(TypeAndMut {ty: ty, mutbl: hir::Mutability::Immutable})
2425     }
2426
2427     #[inline]
2428     pub fn mk_nil_ptr(self) -> Ty<'tcx> {
2429         self.mk_imm_ptr(self.mk_unit())
2430     }
2431
2432     #[inline]
2433     pub fn mk_array(self, ty: Ty<'tcx>, n: u64) -> Ty<'tcx> {
2434         self.mk_ty(Array(ty, ty::Const::from_usize(self, n)))
2435     }
2436
2437     #[inline]
2438     pub fn mk_slice(self, ty: Ty<'tcx>) -> Ty<'tcx> {
2439         self.mk_ty(Slice(ty))
2440     }
2441
2442     #[inline]
2443     pub fn intern_tup(self, ts: &[Ty<'tcx>]) -> Ty<'tcx> {
2444         let kinds: Vec<_> = ts.into_iter().map(|&t| GenericArg::from(t)).collect();
2445         self.mk_ty(Tuple(self.intern_substs(&kinds)))
2446     }
2447
2448     pub fn mk_tup<I: InternAs<[Ty<'tcx>], Ty<'tcx>>>(self, iter: I) -> I::Output {
2449         iter.intern_with(|ts| {
2450             let kinds: Vec<_> = ts.into_iter().map(|&t| GenericArg::from(t)).collect();
2451             self.mk_ty(Tuple(self.intern_substs(&kinds)))
2452         })
2453     }
2454
2455     #[inline]
2456     pub fn mk_unit(self) -> Ty<'tcx> {
2457         self.types.unit
2458     }
2459
2460     #[inline]
2461     pub fn mk_diverging_default(self) -> Ty<'tcx> {
2462         if self.features().never_type_fallback {
2463             self.types.never
2464         } else {
2465             self.types.unit
2466         }
2467     }
2468
2469     #[inline]
2470     pub fn mk_bool(self) -> Ty<'tcx> {
2471         self.mk_ty(Bool)
2472     }
2473
2474     #[inline]
2475     pub fn mk_fn_def(self, def_id: DefId,
2476                      substs: SubstsRef<'tcx>) -> Ty<'tcx> {
2477         self.mk_ty(FnDef(def_id, substs))
2478     }
2479
2480     #[inline]
2481     pub fn mk_fn_ptr(self, fty: PolyFnSig<'tcx>) -> Ty<'tcx> {
2482         self.mk_ty(FnPtr(fty))
2483     }
2484
2485     #[inline]
2486     pub fn mk_dynamic(
2487         self,
2488         obj: ty::Binder<&'tcx List<ExistentialPredicate<'tcx>>>,
2489         reg: ty::Region<'tcx>
2490     ) -> Ty<'tcx> {
2491         self.mk_ty(Dynamic(obj, reg))
2492     }
2493
2494     #[inline]
2495     pub fn mk_projection(self,
2496                          item_def_id: DefId,
2497                          substs: SubstsRef<'tcx>)
2498         -> Ty<'tcx> {
2499             self.mk_ty(Projection(ProjectionTy {
2500                 item_def_id,
2501                 substs,
2502             }))
2503         }
2504
2505     #[inline]
2506     pub fn mk_closure(self, closure_id: DefId, closure_substs: SubstsRef<'tcx>)
2507                       -> Ty<'tcx> {
2508         self.mk_ty(Closure(closure_id, closure_substs))
2509     }
2510
2511     #[inline]
2512     pub fn mk_generator(self,
2513                         id: DefId,
2514                         generator_substs: SubstsRef<'tcx>,
2515                         movability: hir::Movability)
2516                         -> Ty<'tcx> {
2517         self.mk_ty(Generator(id, generator_substs, movability))
2518     }
2519
2520     #[inline]
2521     pub fn mk_generator_witness(self, types: ty::Binder<&'tcx List<Ty<'tcx>>>) -> Ty<'tcx> {
2522         self.mk_ty(GeneratorWitness(types))
2523     }
2524
2525     #[inline]
2526     pub fn mk_ty_var(self, v: TyVid) -> Ty<'tcx> {
2527         self.mk_ty_infer(TyVar(v))
2528     }
2529
2530     #[inline]
2531     pub fn mk_const_var(self, v: ConstVid<'tcx>, ty: Ty<'tcx>) -> &'tcx Const<'tcx> {
2532         self.mk_const(ty::Const {
2533             val: ty::ConstKind::Infer(InferConst::Var(v)),
2534             ty,
2535         })
2536     }
2537
2538     #[inline]
2539     pub fn mk_int_var(self, v: IntVid) -> Ty<'tcx> {
2540         self.mk_ty_infer(IntVar(v))
2541     }
2542
2543     #[inline]
2544     pub fn mk_float_var(self, v: FloatVid) -> Ty<'tcx> {
2545         self.mk_ty_infer(FloatVar(v))
2546     }
2547
2548     #[inline]
2549     pub fn mk_ty_infer(self, it: InferTy) -> Ty<'tcx> {
2550         self.mk_ty(Infer(it))
2551     }
2552
2553     #[inline]
2554     pub fn mk_const_infer(
2555         self,
2556         ic: InferConst<'tcx>,
2557         ty: Ty<'tcx>,
2558     ) -> &'tcx ty::Const<'tcx> {
2559         self.mk_const(ty::Const {
2560             val: ty::ConstKind::Infer(ic),
2561             ty,
2562         })
2563     }
2564
2565     #[inline]
2566     pub fn mk_ty_param(self, index: u32, name: Symbol) -> Ty<'tcx> {
2567         self.mk_ty(Param(ParamTy { index, name: name }))
2568     }
2569
2570     #[inline]
2571     pub fn mk_const_param(
2572         self,
2573         index: u32,
2574         name: Symbol,
2575         ty: Ty<'tcx>
2576     ) -> &'tcx Const<'tcx> {
2577         self.mk_const(ty::Const {
2578             val: ty::ConstKind::Param(ParamConst { index, name }),
2579             ty,
2580         })
2581     }
2582
2583
2584     pub fn mk_param_from_def(self, param: &ty::GenericParamDef) -> GenericArg<'tcx> {
2585         match param.kind {
2586             GenericParamDefKind::Lifetime => {
2587                 self.mk_region(ty::ReEarlyBound(param.to_early_bound_region_data())).into()
2588             }
2589             GenericParamDefKind::Type { .. } => self.mk_ty_param(param.index, param.name).into(),
2590             GenericParamDefKind::Const => {
2591                 self.mk_const_param(param.index, param.name, self.type_of(param.def_id)).into()
2592             }
2593         }
2594     }
2595
2596     #[inline]
2597     pub fn mk_opaque(self, def_id: DefId, substs: SubstsRef<'tcx>) -> Ty<'tcx> {
2598         self.mk_ty(Opaque(def_id, substs))
2599     }
2600
2601     pub fn mk_place_field(self, place: Place<'tcx>, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
2602         self.mk_place_elem(place, PlaceElem::Field(f, ty))
2603     }
2604
2605     pub fn mk_place_deref(self, place: Place<'tcx>) -> Place<'tcx> {
2606         self.mk_place_elem(place, PlaceElem::Deref)
2607     }
2608
2609     pub fn mk_place_downcast(
2610         self,
2611         place: Place<'tcx>,
2612         adt_def: &'tcx AdtDef,
2613         variant_index: VariantIdx,
2614     ) -> Place<'tcx> {
2615         self.mk_place_elem(
2616             place,
2617             PlaceElem::Downcast(Some(adt_def.variants[variant_index].ident.name), variant_index),
2618         )
2619     }
2620
2621     pub fn mk_place_downcast_unnamed(
2622         self,
2623         place: Place<'tcx>,
2624         variant_index: VariantIdx,
2625     ) -> Place<'tcx> {
2626         self.mk_place_elem(place, PlaceElem::Downcast(None, variant_index))
2627     }
2628
2629     pub fn mk_place_index(self, place: Place<'tcx>, index: Local) -> Place<'tcx> {
2630         self.mk_place_elem(place, PlaceElem::Index(index))
2631     }
2632
2633     /// This method copies `Place`'s projection, add an element and reintern it. Should not be used
2634     /// to build a full `Place` it's just a convenient way to grab a projection and modify it in
2635     /// flight.
2636     pub fn mk_place_elem(self, place: Place<'tcx>, elem: PlaceElem<'tcx>) -> Place<'tcx> {
2637         let mut projection = place.projection.to_vec();
2638         projection.push(elem);
2639
2640         Place { base: place.base, projection: self.intern_place_elems(&projection) }
2641     }
2642
2643     pub fn intern_existential_predicates(self, eps: &[ExistentialPredicate<'tcx>])
2644         -> &'tcx List<ExistentialPredicate<'tcx>> {
2645         assert!(!eps.is_empty());
2646         assert!(eps.windows(2).all(|w| w[0].stable_cmp(self, &w[1]) != Ordering::Greater));
2647         self._intern_existential_predicates(eps)
2648     }
2649
2650     pub fn intern_predicates(self, preds: &[Predicate<'tcx>])
2651         -> &'tcx List<Predicate<'tcx>> {
2652         // FIXME consider asking the input slice to be sorted to avoid
2653         // re-interning permutations, in which case that would be asserted
2654         // here.
2655         if preds.len() == 0 {
2656             // The macro-generated method below asserts we don't intern an empty slice.
2657             List::empty()
2658         } else {
2659             self._intern_predicates(preds)
2660         }
2661     }
2662
2663     pub fn intern_type_list(self, ts: &[Ty<'tcx>]) -> &'tcx List<Ty<'tcx>> {
2664         if ts.len() == 0 {
2665             List::empty()
2666         } else {
2667             self._intern_type_list(ts)
2668         }
2669     }
2670
2671     pub fn intern_substs(self, ts: &[GenericArg<'tcx>]) -> &'tcx List<GenericArg<'tcx>> {
2672         if ts.len() == 0 {
2673             List::empty()
2674         } else {
2675             self._intern_substs(ts)
2676         }
2677     }
2678
2679     pub fn intern_projs(self, ps: &[ProjectionKind]) -> &'tcx List<ProjectionKind> {
2680         if ps.len() == 0 {
2681             List::empty()
2682         } else {
2683             self._intern_projs(ps)
2684         }
2685     }
2686
2687     pub fn intern_place_elems(self, ts: &[PlaceElem<'tcx>]) -> &'tcx List<PlaceElem<'tcx>> {
2688         if ts.len() == 0 {
2689             List::empty()
2690         } else {
2691             self._intern_place_elems(ts)
2692         }
2693     }
2694
2695     pub fn intern_canonical_var_infos(self, ts: &[CanonicalVarInfo]) -> CanonicalVarInfos<'tcx> {
2696         if ts.len() == 0 {
2697             List::empty()
2698         } else {
2699             self._intern_canonical_var_infos(ts)
2700         }
2701     }
2702
2703     pub fn intern_clauses(self, ts: &[Clause<'tcx>]) -> Clauses<'tcx> {
2704         if ts.len() == 0 {
2705             List::empty()
2706         } else {
2707             self._intern_clauses(ts)
2708         }
2709     }
2710
2711     pub fn intern_goals(self, ts: &[Goal<'tcx>]) -> Goals<'tcx> {
2712         if ts.len() == 0 {
2713             List::empty()
2714         } else {
2715             self._intern_goals(ts)
2716         }
2717     }
2718
2719     pub fn mk_fn_sig<I>(self,
2720                         inputs: I,
2721                         output: I::Item,
2722                         c_variadic: bool,
2723                         unsafety: hir::Unsafety,
2724                         abi: abi::Abi)
2725         -> <I::Item as InternIteratorElement<Ty<'tcx>, ty::FnSig<'tcx>>>::Output
2726     where
2727         I: Iterator<Item: InternIteratorElement<Ty<'tcx>, ty::FnSig<'tcx>>>,
2728     {
2729         inputs.chain(iter::once(output)).intern_with(|xs| ty::FnSig {
2730             inputs_and_output: self.intern_type_list(xs),
2731             c_variadic, unsafety, abi
2732         })
2733     }
2734
2735     pub fn mk_existential_predicates<I: InternAs<[ExistentialPredicate<'tcx>],
2736                                      &'tcx List<ExistentialPredicate<'tcx>>>>(self, iter: I)
2737                                      -> I::Output {
2738         iter.intern_with(|xs| self.intern_existential_predicates(xs))
2739     }
2740
2741     pub fn mk_predicates<I: InternAs<[Predicate<'tcx>],
2742                                      &'tcx List<Predicate<'tcx>>>>(self, iter: I)
2743                                      -> I::Output {
2744         iter.intern_with(|xs| self.intern_predicates(xs))
2745     }
2746
2747     pub fn mk_type_list<I: InternAs<[Ty<'tcx>],
2748                         &'tcx List<Ty<'tcx>>>>(self, iter: I) -> I::Output {
2749         iter.intern_with(|xs| self.intern_type_list(xs))
2750     }
2751
2752     pub fn mk_substs<I: InternAs<[GenericArg<'tcx>],
2753                      &'tcx List<GenericArg<'tcx>>>>(self, iter: I) -> I::Output {
2754         iter.intern_with(|xs| self.intern_substs(xs))
2755     }
2756
2757     pub fn mk_place_elems<I: InternAs<[PlaceElem<'tcx>],
2758                           &'tcx List<PlaceElem<'tcx>>>>(self, iter: I) -> I::Output {
2759         iter.intern_with(|xs| self.intern_place_elems(xs))
2760     }
2761
2762     pub fn mk_substs_trait(self,
2763                      self_ty: Ty<'tcx>,
2764                      rest: &[GenericArg<'tcx>])
2765                     -> SubstsRef<'tcx>
2766     {
2767         self.mk_substs(iter::once(self_ty.into()).chain(rest.iter().cloned()))
2768     }
2769
2770     pub fn mk_clauses<I: InternAs<[Clause<'tcx>], Clauses<'tcx>>>(self, iter: I) -> I::Output {
2771         iter.intern_with(|xs| self.intern_clauses(xs))
2772     }
2773
2774     pub fn mk_goals<I: InternAs<[Goal<'tcx>], Goals<'tcx>>>(self, iter: I) -> I::Output {
2775         iter.intern_with(|xs| self.intern_goals(xs))
2776     }
2777
2778     pub fn lint_hir<S: Into<MultiSpan>>(self,
2779                                         lint: &'static Lint,
2780                                         hir_id: HirId,
2781                                         span: S,
2782                                         msg: &str) {
2783         self.struct_span_lint_hir(lint, hir_id, span.into(), msg).emit()
2784     }
2785
2786     pub fn lint_hir_note<S: Into<MultiSpan>>(self,
2787                                              lint: &'static Lint,
2788                                              hir_id: HirId,
2789                                              span: S,
2790                                              msg: &str,
2791                                              note: &str) {
2792         let mut err = self.struct_span_lint_hir(lint, hir_id, span.into(), msg);
2793         err.note(note);
2794         err.emit()
2795     }
2796
2797     pub fn lint_node_note<S: Into<MultiSpan>>(self,
2798                                               lint: &'static Lint,
2799                                               id: hir::HirId,
2800                                               span: S,
2801                                               msg: &str,
2802                                               note: &str) {
2803         let mut err = self.struct_span_lint_hir(lint, id, span.into(), msg);
2804         err.note(note);
2805         err.emit()
2806     }
2807
2808     /// Walks upwards from `id` to find a node which might change lint levels with attributes.
2809     /// It stops at `bound` and just returns it if reached.
2810     pub fn maybe_lint_level_root_bounded(
2811         self,
2812         mut id: hir::HirId,
2813         bound: hir::HirId,
2814     ) -> hir::HirId {
2815         loop {
2816             if id == bound {
2817                 return bound;
2818             }
2819             if lint::maybe_lint_level_root(self, id) {
2820                 return id;
2821             }
2822             let next = self.hir().get_parent_node(id);
2823             if next == id {
2824                 bug!("lint traversal reached the root of the crate");
2825             }
2826             id = next;
2827         }
2828     }
2829
2830     pub fn lint_level_at_node(
2831         self,
2832         lint: &'static Lint,
2833         mut id: hir::HirId
2834     ) -> (lint::Level, lint::LintSource) {
2835         let sets = self.lint_levels(LOCAL_CRATE);
2836         loop {
2837             if let Some(pair) = sets.level_and_source(lint, id, self.sess) {
2838                 return pair
2839             }
2840             let next = self.hir().get_parent_node(id);
2841             if next == id {
2842                 bug!("lint traversal reached the root of the crate");
2843             }
2844             id = next;
2845         }
2846     }
2847
2848     pub fn struct_span_lint_hir<S: Into<MultiSpan>>(self,
2849                                                     lint: &'static Lint,
2850                                                     hir_id: HirId,
2851                                                     span: S,
2852                                                     msg: &str)
2853         -> DiagnosticBuilder<'tcx>
2854     {
2855         let (level, src) = self.lint_level_at_node(lint, hir_id);
2856         lint::struct_lint_level(self.sess, lint, level, src, Some(span.into()), msg)
2857     }
2858
2859     pub fn struct_lint_node(self, lint: &'static Lint, id: HirId, msg: &str)
2860         -> DiagnosticBuilder<'tcx>
2861     {
2862         let (level, src) = self.lint_level_at_node(lint, id);
2863         lint::struct_lint_level(self.sess, lint, level, src, None, msg)
2864     }
2865
2866     pub fn in_scope_traits(self, id: HirId) -> Option<&'tcx StableVec<TraitCandidate>> {
2867         self.in_scope_traits_map(id.owner)
2868             .and_then(|map| map.get(&id.local_id))
2869     }
2870
2871     pub fn named_region(self, id: HirId) -> Option<resolve_lifetime::Region> {
2872         self.named_region_map(id.owner)
2873             .and_then(|map| map.get(&id.local_id).cloned())
2874     }
2875
2876     pub fn is_late_bound(self, id: HirId) -> bool {
2877         self.is_late_bound_map(id.owner)
2878             .map(|set| set.contains(&id.local_id))
2879             .unwrap_or(false)
2880     }
2881
2882     pub fn object_lifetime_defaults(self, id: HirId) -> Option<&'tcx [ObjectLifetimeDefault]> {
2883         self.object_lifetime_defaults_map(id.owner)
2884             .and_then(|map| map.get(&id.local_id).map(|v| &**v))
2885     }
2886 }
2887
2888 pub trait InternAs<T: ?Sized, R> {
2889     type Output;
2890     fn intern_with<F>(self, f: F) -> Self::Output
2891         where F: FnOnce(&T) -> R;
2892 }
2893
2894 impl<I, T, R, E> InternAs<[T], R> for I
2895     where E: InternIteratorElement<T, R>,
2896           I: Iterator<Item=E> {
2897     type Output = E::Output;
2898     fn intern_with<F>(self, f: F) -> Self::Output
2899         where F: FnOnce(&[T]) -> R {
2900         E::intern_with(self, f)
2901     }
2902 }
2903
2904 pub trait InternIteratorElement<T, R>: Sized {
2905     type Output;
2906     fn intern_with<I: Iterator<Item=Self>, F: FnOnce(&[T]) -> R>(iter: I, f: F) -> Self::Output;
2907 }
2908
2909 impl<T, R> InternIteratorElement<T, R> for T {
2910     type Output = R;
2911     fn intern_with<I: Iterator<Item=Self>, F: FnOnce(&[T]) -> R>(iter: I, f: F) -> Self::Output {
2912         f(&iter.collect::<SmallVec<[_; 8]>>())
2913     }
2914 }
2915
2916 impl<'a, T, R> InternIteratorElement<T, R> for &'a T
2917     where T: Clone + 'a
2918 {
2919     type Output = R;
2920     fn intern_with<I: Iterator<Item=Self>, F: FnOnce(&[T]) -> R>(iter: I, f: F) -> Self::Output {
2921         f(&iter.cloned().collect::<SmallVec<[_; 8]>>())
2922     }
2923 }
2924
2925 impl<T, R, E> InternIteratorElement<T, R> for Result<T, E> {
2926     type Output = Result<R, E>;
2927     fn intern_with<I: Iterator<Item=Self>, F: FnOnce(&[T]) -> R>(mut iter: I, f: F)
2928             -> Self::Output {
2929         // This code is hot enough that it's worth specializing for the most
2930         // common length lists, to avoid the overhead of `SmallVec` creation.
2931         // The match arms are in order of frequency. The 1, 2, and 0 cases are
2932         // typically hit in ~95% of cases. We assume that if the upper and
2933         // lower bounds from `size_hint` agree they are correct.
2934         Ok(match iter.size_hint() {
2935             (1, Some(1)) => {
2936                 let t0 = iter.next().unwrap()?;
2937                 assert!(iter.next().is_none());
2938                 f(&[t0])
2939             }
2940             (2, Some(2)) => {
2941                 let t0 = iter.next().unwrap()?;
2942                 let t1 = iter.next().unwrap()?;
2943                 assert!(iter.next().is_none());
2944                 f(&[t0, t1])
2945             }
2946             (0, Some(0)) => {
2947                 assert!(iter.next().is_none());
2948                 f(&[])
2949             }
2950             _ => {
2951                 f(&iter.collect::<Result<SmallVec<[_; 8]>, _>>()?)
2952             }
2953         })
2954     }
2955 }
2956
2957 // We are comparing types with different invariant lifetimes, so `ptr::eq`
2958 // won't work for us.
2959 fn ptr_eq<T, U>(t: *const T, u: *const U) -> bool {
2960     t as *const () == u as *const ()
2961 }
2962
2963 pub fn provide(providers: &mut ty::query::Providers<'_>) {
2964     providers.in_scope_traits_map = |tcx, id| tcx.gcx.trait_map.get(&id);
2965     providers.module_exports = |tcx, id| tcx.gcx.export_map.get(&id).map(|v| &v[..]);
2966     providers.crate_name = |tcx, id| {
2967         assert_eq!(id, LOCAL_CRATE);
2968         tcx.crate_name
2969     };
2970     providers.get_lib_features = |tcx, id| {
2971         assert_eq!(id, LOCAL_CRATE);
2972         tcx.arena.alloc(middle::lib_features::collect(tcx))
2973     };
2974     providers.get_lang_items = |tcx, id| {
2975         assert_eq!(id, LOCAL_CRATE);
2976         tcx.arena.alloc(middle::lang_items::collect(tcx))
2977     };
2978     providers.diagnostic_items = |tcx, id| {
2979         assert_eq!(id, LOCAL_CRATE);
2980         middle::diagnostic_items::collect(tcx)
2981     };
2982     providers.all_diagnostic_items = |tcx, id| {
2983         assert_eq!(id, LOCAL_CRATE);
2984         middle::diagnostic_items::collect_all(tcx)
2985     };
2986     providers.maybe_unused_trait_import = |tcx, id| {
2987         tcx.maybe_unused_trait_imports.contains(&id)
2988     };
2989     providers.maybe_unused_extern_crates = |tcx, cnum| {
2990         assert_eq!(cnum, LOCAL_CRATE);
2991         &tcx.maybe_unused_extern_crates[..]
2992     };
2993     providers.names_imported_by_glob_use = |tcx, id| {
2994         assert_eq!(id.krate, LOCAL_CRATE);
2995         Lrc::new(tcx.glob_map.get(&id).cloned().unwrap_or_default())
2996     };
2997
2998     providers.stability_index = |tcx, cnum| {
2999         assert_eq!(cnum, LOCAL_CRATE);
3000         tcx.arena.alloc(stability::Index::new(tcx))
3001     };
3002     providers.lookup_stability = |tcx, id| {
3003         assert_eq!(id.krate, LOCAL_CRATE);
3004         let id = tcx.hir().definitions().def_index_to_hir_id(id.index);
3005         tcx.stability().local_stability(id)
3006     };
3007     providers.lookup_const_stability = |tcx, id| {
3008         assert_eq!(id.krate, LOCAL_CRATE);
3009         let id = tcx.hir().definitions().def_index_to_hir_id(id.index);
3010         tcx.stability().local_const_stability(id)
3011     };
3012     providers.lookup_deprecation_entry = |tcx, id| {
3013         assert_eq!(id.krate, LOCAL_CRATE);
3014         let id = tcx.hir().definitions().def_index_to_hir_id(id.index);
3015         tcx.stability().local_deprecation_entry(id)
3016     };
3017     providers.extern_mod_stmt_cnum = |tcx, id| {
3018         let id = tcx.hir().as_local_node_id(id).unwrap();
3019         tcx.extern_crate_map.get(&id).cloned()
3020     };
3021     providers.all_crate_nums = |tcx, cnum| {
3022         assert_eq!(cnum, LOCAL_CRATE);
3023         tcx.arena.alloc_slice(&tcx.cstore.crates_untracked())
3024     };
3025     providers.output_filenames = |tcx, cnum| {
3026         assert_eq!(cnum, LOCAL_CRATE);
3027         tcx.output_filenames.clone()
3028     };
3029     providers.features_query = |tcx, cnum| {
3030         assert_eq!(cnum, LOCAL_CRATE);
3031         tcx.arena.alloc(tcx.sess.features_untracked().clone())
3032     };
3033     providers.is_panic_runtime = |tcx, cnum| {
3034         assert_eq!(cnum, LOCAL_CRATE);
3035         attr::contains_name(tcx.hir().krate_attrs(), sym::panic_runtime)
3036     };
3037     providers.is_compiler_builtins = |tcx, cnum| {
3038         assert_eq!(cnum, LOCAL_CRATE);
3039         attr::contains_name(tcx.hir().krate_attrs(), sym::compiler_builtins)
3040     };
3041     providers.has_panic_handler = |tcx, cnum| {
3042         assert_eq!(cnum, LOCAL_CRATE);
3043         // We want to check if the panic handler was defined in this crate
3044         tcx.lang_items().panic_impl().map_or(false, |did| did.is_local())
3045     };
3046 }