src/librustc/hir/mod.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // The Rust HIR.
  12
  13 pub use self::BindingMode::*;
  14 pub use self::BinOp_::*;
  15 pub use self::BlockCheckMode::*;
  16 pub use self::CaptureClause::*;
  17 pub use self::Decl_::*;
  18 pub use self::Expr_::*;
  19 pub use self::FunctionRetTy::*;
  20 pub use self::ForeignItem_::*;
  21 pub use self::Item_::*;
  22 pub use self::Mutability::*;
  23 pub use self::PrimTy::*;
  24 pub use self::Stmt_::*;
  25 pub use self::Ty_::*;
  26 pub use self::TyParamBound::*;
  27 pub use self::UnOp::*;
  28 pub use self::UnsafeSource::*;
  29 pub use self::Visibility::{Public, Inherited};
  30 pub use self::PathParameters::*;
  31
  32 use hir::def::Def;
  33 use hir::def_id::{DefId, DefIndex, CRATE_DEF_INDEX};
  34 use util::nodemap::{NodeMap, FxHashSet};
  35
  36 use syntax_pos::{Span, DUMMY_SP};
  37 use syntax::codemap::{self, Spanned};
  38 use syntax::abi::Abi;
  39 use syntax::ast::{Ident, Name, NodeId, DUMMY_NODE_ID, AsmDialect};
  40 use syntax::ast::{Attribute, Lit, StrStyle, FloatTy, IntTy, UintTy, MetaItem};
  41 use syntax::ext::hygiene::SyntaxContext;
  42 use syntax::ptr::P;
  43 use syntax::symbol::{Symbol, keywords};
  44 use syntax::tokenstream::TokenStream;
  45 use syntax::util::ThinVec;
  46
  47 use rustc_data_structures::indexed_vec;
  48
  49 use std::collections::BTreeMap;
  50 use std::fmt;
  51
  52 /// HIR doesn't commit to a concrete storage type and have its own alias for a vector.
  53 /// It can be `Vec`, `P<[T]>` or potentially `Box<[T]>`, or some other container with similar
  54 /// behavior. Unlike AST, HIR is mostly a static structure, so we can use an owned slice instead
  55 /// of `Vec` to avoid keeping extra capacity.
  56 pub type HirVec<T> = P<[T]>;
  57
  58 macro_rules! hir_vec {
  59     ($elem:expr; $n:expr) => (
  60         $crate::hir::HirVec::from(vec![$elem; $n])
  61     );
  62     ($($x:expr),*) => (
  63         $crate::hir::HirVec::from(vec![$($x),*])
  64     );
  65     ($($x:expr,)*) => (hir_vec![$($x),*])
  66 }
  67
  68 pub mod check_attr;
  69 pub mod def;
  70 pub mod def_id;
  71 pub mod intravisit;
  72 pub mod itemlikevisit;
  73 pub mod lowering;
  74 pub mod map;
  75 pub mod pat_util;
  76 pub mod print;
  77 pub mod svh;
  78
  79 /// A HirId uniquely identifies a node in the HIR of then current crate. It is
  80 /// composed of the `owner`, which is the DefIndex of the directly enclosing
  81 /// hir::Item, hir::TraitItem, or hir::ImplItem (i.e. the closest "item-like"),
  82 /// and the `local_id` which is unique within the given owner.
  83 ///
  84 /// This two-level structure makes for more stable values: One can move an item
  85 /// around within the source code, or add or remove stuff before it, without
  86 /// the local_id part of the HirId changing, which is a very useful property
  87 /// incremental compilation where we have to persist things through changes to
  88 /// the code base.
  89 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Debug,
  90          RustcEncodable, RustcDecodable)]
  91 pub struct HirId {
  92     pub owner: DefIndex,
  93     pub local_id: ItemLocalId,
  94 }
  95
  96 /// An `ItemLocalId` uniquely identifies something within a given "item-like",
  97 /// that is within a hir::Item, hir::TraitItem, or hir::ImplItem. There is no
  98 /// guarantee that the numerical value of a given `ItemLocalId` corresponds to
  99 /// the node's position within the owning item in any way, but there is a
 100 /// guarantee that the `LocalItemId`s within an owner occupy a dense range of
 101 /// integers starting at zero, so a mapping that maps all or most nodes within
 102 /// an "item-like" to something else can be implement by a `Vec` instead of a
 103 /// tree or hash map.
 104 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Debug,
 105          RustcEncodable, RustcDecodable)]
 106 pub struct ItemLocalId(pub u32);
 107
 108 impl ItemLocalId {
 109     pub fn as_usize(&self) -> usize {
 110         self.0 as usize
 111     }
 112 }
 113
 114 impl indexed_vec::Idx for ItemLocalId {
 115     fn new(idx: usize) -> Self {
 116         debug_assert!((idx as u32) as usize == idx);
 117         ItemLocalId(idx as u32)
 118     }
 119
 120     fn index(self) -> usize {
 121         self.0 as usize
 122     }
 123 }
 124
 125 /// The `HirId` corresponding to CRATE_NODE_ID and CRATE_DEF_INDEX
 126 pub const CRATE_HIR_ID: HirId = HirId {
 127     owner: CRATE_DEF_INDEX,
 128     local_id: ItemLocalId(0)
 129 };
 130
 131 pub const DUMMY_HIR_ID: HirId = HirId {
 132     owner: CRATE_DEF_INDEX,
 133     local_id: ItemLocalId(!0)
 134 };
 135
 136 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
 137 pub struct Lifetime {
 138     pub id: NodeId,
 139     pub span: Span,
 140
 141     /// Either "'a", referring to a named lifetime definition,
 142     /// or "" (aka keywords::Invalid), for elision placeholders.
 143     ///
 144     /// HIR lowering inserts these placeholders in type paths that
 145     /// refer to type definitions needing lifetime parameters,
 146     /// `&T` and `&mut T`, and trait objects without `... + 'a`.
 147     pub name: Name,
 148 }
 149
 150 impl fmt::Debug for Lifetime {
 151     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 152         write!(f,
 153                "lifetime({}: {})",
 154                self.id,
 155                print::to_string(print::NO_ANN, |s| s.print_lifetime(self)))
 156     }
 157 }
 158
 159 impl Lifetime {
 160     pub fn is_elided(&self) -> bool {
 161         self.name == keywords::Invalid.name()
 162     }
 163
 164     pub fn is_static(&self) -> bool {
 165         self.name == "'static"
 166     }
 167 }
 168
 169 /// A lifetime definition, eg `'a: 'b+'c+'d`
 170 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 171 pub struct LifetimeDef {
 172     pub lifetime: Lifetime,
 173     pub bounds: HirVec<Lifetime>,
 174     pub pure_wrt_drop: bool,
 175 }
 176
 177 /// A "Path" is essentially Rust's notion of a name; for instance:
 178 /// std::cmp::PartialEq  .  It's represented as a sequence of identifiers,
 179 /// along with a bunch of supporting information.
 180 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 181 pub struct Path {
 182     pub span: Span,
 183     /// The definition that the path resolved to.
 184     pub def: Def,
 185     /// The segments in the path: the things separated by `::`.
 186     pub segments: HirVec<PathSegment>,
 187 }
 188
 189 impl Path {
 190     pub fn is_global(&self) -> bool {
 191         !self.segments.is_empty() && self.segments[0].name == keywords::CrateRoot.name()
 192     }
 193 }
 194
 195 impl fmt::Debug for Path {
 196     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 197         write!(f, "path({})",
 198                print::to_string(print::NO_ANN, |s| s.print_path(self, false)))
 199     }
 200 }
 201
 202 /// A segment of a path: an identifier, an optional lifetime, and a set of
 203 /// types.
 204 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 205 pub struct PathSegment {
 206     /// The identifier portion of this path segment.
 207     pub name: Name,
 208
 209     /// Type/lifetime parameters attached to this path. They come in
 210     /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`. Note that
 211     /// this is more than just simple syntactic sugar; the use of
 212     /// parens affects the region binding rules, so we preserve the
 213     /// distinction.
 214     pub parameters: PathParameters,
 215 }
 216
 217 impl PathSegment {
 218     /// Convert an identifier to the corresponding segment.
 219     pub fn from_name(name: Name) -> PathSegment {
 220         PathSegment {
 221             name,
 222             parameters: PathParameters::none()
 223         }
 224     }
 225 }
 226
 227 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 228 pub enum PathParameters {
 229     /// The `<'a, A,B,C>` in `foo::bar::baz::<'a, A,B,C>`
 230     AngleBracketedParameters(AngleBracketedParameterData),
 231     /// The `(A,B)` and `C` in `Foo(A,B) -> C`
 232     ParenthesizedParameters(ParenthesizedParameterData),
 233 }
 234
 235 impl PathParameters {
 236     pub fn none() -> PathParameters {
 237         AngleBracketedParameters(AngleBracketedParameterData {
 238             lifetimes: HirVec::new(),
 239             types: HirVec::new(),
 240             infer_types: true,
 241             bindings: HirVec::new(),
 242         })
 243     }
 244
 245     /// Returns the types that the user wrote. Note that these do not necessarily map to the type
 246     /// parameters in the parenthesized case.
 247     pub fn types(&self) -> HirVec<&P<Ty>> {
 248         match *self {
 249             AngleBracketedParameters(ref data) => {
 250                 data.types.iter().collect()
 251             }
 252             ParenthesizedParameters(ref data) => {
 253                 data.inputs
 254                     .iter()
 255                     .chain(data.output.iter())
 256                     .collect()
 257             }
 258         }
 259     }
 260
 261     pub fn lifetimes(&self) -> HirVec<&Lifetime> {
 262         match *self {
 263             AngleBracketedParameters(ref data) => {
 264                 data.lifetimes.iter().collect()
 265             }
 266             ParenthesizedParameters(_) => {
 267                 HirVec::new()
 268             }
 269         }
 270     }
 271
 272     pub fn bindings(&self) -> HirVec<&TypeBinding> {
 273         match *self {
 274             AngleBracketedParameters(ref data) => {
 275                 data.bindings.iter().collect()
 276             }
 277             ParenthesizedParameters(_) => {
 278                 HirVec::new()
 279             }
 280         }
 281     }
 282 }
 283
 284 /// A path like `Foo<'a, T>`
 285 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 286 pub struct AngleBracketedParameterData {
 287     /// The lifetime parameters for this path segment.
 288     pub lifetimes: HirVec<Lifetime>,
 289     /// The type parameters for this path segment, if present.
 290     pub types: HirVec<P<Ty>>,
 291     /// Whether to infer remaining type parameters, if any.
 292     /// This only applies to expression and pattern paths, and
 293     /// out of those only the segments with no type parameters
 294     /// to begin with, e.g. `Vec::new` is `<Vec<..>>::new::<..>`.
 295     pub infer_types: bool,
 296     /// Bindings (equality constraints) on associated types, if present.
 297     /// E.g., `Foo<A=Bar>`.
 298     pub bindings: HirVec<TypeBinding>,
 299 }
 300
 301 /// A path like `Foo(A,B) -> C`
 302 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 303 pub struct ParenthesizedParameterData {
 304     /// Overall span
 305     pub span: Span,
 306
 307     /// `(A,B)`
 308     pub inputs: HirVec<P<Ty>>,
 309
 310     /// `C`
 311     pub output: Option<P<Ty>>,
 312 }
 313
 314 /// The AST represents all type param bounds as types.
 315 /// typeck::collect::compute_bounds matches these against
 316 /// the "special" built-in traits (see middle::lang_items) and
 317 /// detects Copy, Send and Sync.
 318 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 319 pub enum TyParamBound {
 320     TraitTyParamBound(PolyTraitRef, TraitBoundModifier),
 321     RegionTyParamBound(Lifetime),
 322 }
 323
 324 /// A modifier on a bound, currently this is only used for `?Sized`, where the
 325 /// modifier is `Maybe`. Negative bounds should also be handled here.
 326 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 327 pub enum TraitBoundModifier {
 328     None,
 329     Maybe,
 330 }
 331
 332 pub type TyParamBounds = HirVec<TyParamBound>;
 333
 334 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 335 pub struct TyParam {
 336     pub name: Name,
 337     pub id: NodeId,
 338     pub bounds: TyParamBounds,
 339     pub default: Option<P<Ty>>,
 340     pub span: Span,
 341     pub pure_wrt_drop: bool,
 342 }
 343
 344 /// Represents lifetimes and type parameters attached to a declaration
 345 /// of a function, enum, trait, etc.
 346 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 347 pub struct Generics {
 348     pub lifetimes: HirVec<LifetimeDef>,
 349     pub ty_params: HirVec<TyParam>,
 350     pub where_clause: WhereClause,
 351     pub span: Span,
 352 }
 353
 354 impl Generics {
 355     pub fn empty() -> Generics {
 356         Generics {
 357             lifetimes: HirVec::new(),
 358             ty_params: HirVec::new(),
 359             where_clause: WhereClause {
 360                 id: DUMMY_NODE_ID,
 361                 predicates: HirVec::new(),
 362             },
 363             span: DUMMY_SP,
 364         }
 365     }
 366
 367     pub fn is_lt_parameterized(&self) -> bool {
 368         !self.lifetimes.is_empty()
 369     }
 370
 371     pub fn is_type_parameterized(&self) -> bool {
 372         !self.ty_params.is_empty()
 373     }
 374
 375     pub fn is_parameterized(&self) -> bool {
 376         self.is_lt_parameterized() || self.is_type_parameterized()
 377     }
 378 }
 379
 380 pub enum UnsafeGeneric {
 381     Region(LifetimeDef, &'static str),
 382     Type(TyParam, &'static str),
 383 }
 384
 385 impl UnsafeGeneric {
 386     pub fn attr_name(&self) -> &'static str {
 387         match *self {
 388             UnsafeGeneric::Region(_, s) => s,
 389             UnsafeGeneric::Type(_, s) => s,
 390         }
 391     }
 392 }
 393
 394 impl Generics {
 395     pub fn carries_unsafe_attr(&self) -> Option<UnsafeGeneric> {
 396         for r in &self.lifetimes {
 397             if r.pure_wrt_drop {
 398                 return Some(UnsafeGeneric::Region(r.clone(), "may_dangle"));
 399             }
 400         }
 401         for t in &self.ty_params {
 402             if t.pure_wrt_drop {
 403                 return Some(UnsafeGeneric::Type(t.clone(), "may_dangle"));
 404             }
 405         }
 406         return None;
 407     }
 408 }
 409
 410 /// A `where` clause in a definition
 411 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 412 pub struct WhereClause {
 413     pub id: NodeId,
 414     pub predicates: HirVec<WherePredicate>,
 415 }
 416
 417 /// A single predicate in a `where` clause
 418 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 419 pub enum WherePredicate {
 420     /// A type binding, eg `for<'c> Foo: Send+Clone+'c`
 421     BoundPredicate(WhereBoundPredicate),
 422     /// A lifetime predicate, e.g. `'a: 'b+'c`
 423     RegionPredicate(WhereRegionPredicate),
 424     /// An equality predicate (unsupported)
 425     EqPredicate(WhereEqPredicate),
 426 }
 427
 428 /// A type bound, eg `for<'c> Foo: Send+Clone+'c`
 429 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 430 pub struct WhereBoundPredicate {
 431     pub span: Span,
 432     /// Any lifetimes from a `for` binding
 433     pub bound_lifetimes: HirVec<LifetimeDef>,
 434     /// The type being bounded
 435     pub bounded_ty: P<Ty>,
 436     /// Trait and lifetime bounds (`Clone+Send+'static`)
 437     pub bounds: TyParamBounds,
 438 }
 439
 440 /// A lifetime predicate, e.g. `'a: 'b+'c`
 441 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 442 pub struct WhereRegionPredicate {
 443     pub span: Span,
 444     pub lifetime: Lifetime,
 445     pub bounds: HirVec<Lifetime>,
 446 }
 447
 448 /// An equality predicate (unsupported), e.g. `T=int`
 449 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 450 pub struct WhereEqPredicate {
 451     pub id: NodeId,
 452     pub span: Span,
 453     pub lhs_ty: P<Ty>,
 454     pub rhs_ty: P<Ty>,
 455 }
 456
 457 pub type CrateConfig = HirVec<P<MetaItem>>;
 458
 459 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
 460 pub struct Crate {
 461     pub module: Mod,
 462     pub attrs: HirVec<Attribute>,
 463     pub span: Span,
 464     pub exported_macros: HirVec<MacroDef>,
 465
 466     // NB: We use a BTreeMap here so that `visit_all_items` iterates
 467     // over the ids in increasing order. In principle it should not
 468     // matter what order we visit things in, but in *practice* it
 469     // does, because it can affect the order in which errors are
 470     // detected, which in turn can make compile-fail tests yield
 471     // slightly different results.
 472     pub items: BTreeMap<NodeId, Item>,
 473
 474     pub trait_items: BTreeMap<TraitItemId, TraitItem>,
 475     pub impl_items: BTreeMap<ImplItemId, ImplItem>,
 476     pub bodies: BTreeMap<BodyId, Body>,
 477     pub trait_impls: BTreeMap<DefId, Vec<NodeId>>,
 478     pub trait_default_impl: BTreeMap<DefId, NodeId>,
 479
 480     /// A list of the body ids written out in the order in which they
 481     /// appear in the crate. If you're going to process all the bodies
 482     /// in the crate, you should iterate over this list rather than the keys
 483     /// of bodies.
 484     pub body_ids: Vec<BodyId>,
 485 }
 486
 487 impl Crate {
 488     pub fn item(&self, id: NodeId) -> &Item {
 489         &self.items[&id]
 490     }
 491
 492     pub fn trait_item(&self, id: TraitItemId) -> &TraitItem {
 493         &self.trait_items[&id]
 494     }
 495
 496     pub fn impl_item(&self, id: ImplItemId) -> &ImplItem {
 497         &self.impl_items[&id]
 498     }
 499
 500     /// Visits all items in the crate in some determinstic (but
 501     /// unspecified) order. If you just need to process every item,
 502     /// but don't care about nesting, this method is the best choice.
 503     ///
 504     /// If you do care about nesting -- usually because your algorithm
 505     /// follows lexical scoping rules -- then you want a different
 506     /// approach. You should override `visit_nested_item` in your
 507     /// visitor and then call `intravisit::walk_crate` instead.
 508     pub fn visit_all_item_likes<'hir, V>(&'hir self, visitor: &mut V)
 509         where V: itemlikevisit::ItemLikeVisitor<'hir>
 510     {
 511         for (_, item) in &self.items {
 512             visitor.visit_item(item);
 513         }
 514
 515         for (_, trait_item) in &self.trait_items {
 516             visitor.visit_trait_item(trait_item);
 517         }
 518
 519         for (_, impl_item) in &self.impl_items {
 520             visitor.visit_impl_item(impl_item);
 521         }
 522     }
 523
 524     pub fn body(&self, id: BodyId) -> &Body {
 525         &self.bodies[&id]
 526     }
 527 }
 528
 529 /// A macro definition, in this crate or imported from another.
 530 ///
 531 /// Not parsed directly, but created on macro import or `macro_rules!` expansion.
 532 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 533 pub struct MacroDef {
 534     pub name: Name,
 535     pub vis: Visibility,
 536     pub attrs: HirVec<Attribute>,
 537     pub id: NodeId,
 538     pub span: Span,
 539     pub body: TokenStream,
 540     pub legacy: bool,
 541 }
 542
 543 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 544 pub struct Block {
 545     /// Statements in a block
 546     pub stmts: HirVec<Stmt>,
 547     /// An expression at the end of the block
 548     /// without a semicolon, if any
 549     pub expr: Option<P<Expr>>,
 550     pub id: NodeId,
 551     /// Distinguishes between `unsafe { ... }` and `{ ... }`
 552     pub rules: BlockCheckMode,
 553     pub span: Span,
 554     /// If true, then there may exist `break 'a` values that aim to
 555     /// break out of this block early. As of this writing, this is not
 556     /// currently permitted in Rust itself, but it is generated as
 557     /// part of `catch` statements.
 558     pub targeted_by_break: bool,
 559 }
 560
 561 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 562 pub struct Pat {
 563     pub id: NodeId,
 564     pub node: PatKind,
 565     pub span: Span,
 566 }
 567
 568 impl fmt::Debug for Pat {
 569     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 570         write!(f, "pat({}: {})", self.id,
 571                print::to_string(print::NO_ANN, |s| s.print_pat(self)))
 572     }
 573 }
 574
 575 impl Pat {
 576     // FIXME(#19596) this is a workaround, but there should be a better way
 577     fn walk_<G>(&self, it: &mut G) -> bool
 578         where G: FnMut(&Pat) -> bool
 579     {
 580         if !it(self) {
 581             return false;
 582         }
 583
 584         match self.node {
 585             PatKind::Binding(.., Some(ref p)) => p.walk_(it),
 586             PatKind::Struct(_, ref fields, _) => {
 587                 fields.iter().all(|field| field.node.pat.walk_(it))
 588             }
 589             PatKind::TupleStruct(_, ref s, _) | PatKind::Tuple(ref s, _) => {
 590                 s.iter().all(|p| p.walk_(it))
 591             }
 592             PatKind::Box(ref s) | PatKind::Ref(ref s, _) => {
 593                 s.walk_(it)
 594             }
 595             PatKind::Slice(ref before, ref slice, ref after) => {
 596                 before.iter().all(|p| p.walk_(it)) &&
 597                 slice.iter().all(|p| p.walk_(it)) &&
 598                 after.iter().all(|p| p.walk_(it))
 599             }
 600             PatKind::Wild |
 601             PatKind::Lit(_) |
 602             PatKind::Range(..) |
 603             PatKind::Binding(..) |
 604             PatKind::Path(_) => {
 605                 true
 606             }
 607         }
 608     }
 609
 610     pub fn walk<F>(&self, mut it: F) -> bool
 611         where F: FnMut(&Pat) -> bool
 612     {
 613         self.walk_(&mut it)
 614     }
 615 }
 616
 617 /// A single field in a struct pattern
 618 ///
 619 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
 620 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
 621 /// except is_shorthand is true
 622 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 623 pub struct FieldPat {
 624     /// The identifier for the field
 625     pub name: Name,
 626     /// The pattern the field is destructured to
 627     pub pat: P<Pat>,
 628     pub is_shorthand: bool,
 629 }
 630
 631 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 632 pub enum BindingMode {
 633     BindByRef(Mutability),
 634     BindByValue(Mutability),
 635 }
 636
 637 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 638 pub enum RangeEnd {
 639     Included,
 640     Excluded,
 641 }
 642
 643 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 644 pub enum PatKind {
 645     /// Represents a wildcard pattern (`_`)
 646     Wild,
 647
 648     /// A fresh binding `ref mut binding @ OPT_SUBPATTERN`.
 649     /// The `DefId` is for the definition of the variable being bound.
 650     Binding(BindingMode, DefId, Spanned<Name>, Option<P<Pat>>),
 651
 652     /// A struct or struct variant pattern, e.g. `Variant {x, y, ..}`.
 653     /// The `bool` is `true` in the presence of a `..`.
 654     Struct(QPath, HirVec<Spanned<FieldPat>>, bool),
 655
 656     /// A tuple struct/variant pattern `Variant(x, y, .., z)`.
 657     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
 658     /// 0 <= position <= subpats.len()
 659     TupleStruct(QPath, HirVec<P<Pat>>, Option<usize>),
 660
 661     /// A path pattern for an unit struct/variant or a (maybe-associated) constant.
 662     Path(QPath),
 663
 664     /// A tuple pattern `(a, b)`.
 665     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
 666     /// 0 <= position <= subpats.len()
 667     Tuple(HirVec<P<Pat>>, Option<usize>),
 668     /// A `box` pattern
 669     Box(P<Pat>),
 670     /// A reference pattern, e.g. `&mut (a, b)`
 671     Ref(P<Pat>, Mutability),
 672     /// A literal
 673     Lit(P<Expr>),
 674     /// A range pattern, e.g. `1...2` or `1..2`
 675     Range(P<Expr>, P<Expr>, RangeEnd),
 676     /// `[a, b, ..i, y, z]` is represented as:
 677     ///     `PatKind::Slice(box [a, b], Some(i), box [y, z])`
 678     Slice(HirVec<P<Pat>>, Option<P<Pat>>, HirVec<P<Pat>>),
 679 }
 680
 681 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 682 pub enum Mutability {
 683     MutMutable,
 684     MutImmutable,
 685 }
 686
 687 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 688 pub enum BinOp_ {
 689     /// The `+` operator (addition)
 690     BiAdd,
 691     /// The `-` operator (subtraction)
 692     BiSub,
 693     /// The `*` operator (multiplication)
 694     BiMul,
 695     /// The `/` operator (division)
 696     BiDiv,
 697     /// The `%` operator (modulus)
 698     BiRem,
 699     /// The `&&` operator (logical and)
 700     BiAnd,
 701     /// The `||` operator (logical or)
 702     BiOr,
 703     /// The `^` operator (bitwise xor)
 704     BiBitXor,
 705     /// The `&` operator (bitwise and)
 706     BiBitAnd,
 707     /// The `|` operator (bitwise or)
 708     BiBitOr,
 709     /// The `<<` operator (shift left)
 710     BiShl,
 711     /// The `>>` operator (shift right)
 712     BiShr,
 713     /// The `==` operator (equality)
 714     BiEq,
 715     /// The `<` operator (less than)
 716     BiLt,
 717     /// The `<=` operator (less than or equal to)
 718     BiLe,
 719     /// The `!=` operator (not equal to)
 720     BiNe,
 721     /// The `>=` operator (greater than or equal to)
 722     BiGe,
 723     /// The `>` operator (greater than)
 724     BiGt,
 725 }
 726
 727 impl BinOp_ {
 728     pub fn as_str(self) -> &'static str {
 729         match self {
 730             BiAdd => "+",
 731             BiSub => "-",
 732             BiMul => "*",
 733             BiDiv => "/",
 734             BiRem => "%",
 735             BiAnd => "&&",
 736             BiOr => "||",
 737             BiBitXor => "^",
 738             BiBitAnd => "&",
 739             BiBitOr => "|",
 740             BiShl => "<<",
 741             BiShr => ">>",
 742             BiEq => "==",
 743             BiLt => "<",
 744             BiLe => "<=",
 745             BiNe => "!=",
 746             BiGe => ">=",
 747             BiGt => ">",
 748         }
 749     }
 750
 751     pub fn is_lazy(self) -> bool {
 752         match self {
 753             BiAnd | BiOr => true,
 754             _ => false,
 755         }
 756     }
 757
 758     pub fn is_shift(self) -> bool {
 759         match self {
 760             BiShl | BiShr => true,
 761             _ => false,
 762         }
 763     }
 764
 765     pub fn is_comparison(self) -> bool {
 766         match self {
 767             BiEq | BiLt | BiLe | BiNe | BiGt | BiGe => true,
 768             BiAnd |
 769             BiOr |
 770             BiAdd |
 771             BiSub |
 772             BiMul |
 773             BiDiv |
 774             BiRem |
 775             BiBitXor |
 776             BiBitAnd |
 777             BiBitOr |
 778             BiShl |
 779             BiShr => false,
 780         }
 781     }
 782
 783     /// Returns `true` if the binary operator takes its arguments by value
 784     pub fn is_by_value(self) -> bool {
 785         !self.is_comparison()
 786     }
 787 }
 788
 789 pub type BinOp = Spanned<BinOp_>;
 790
 791 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 792 pub enum UnOp {
 793     /// The `*` operator for dereferencing
 794     UnDeref,
 795     /// The `!` operator for logical inversion
 796     UnNot,
 797     /// The `-` operator for negation
 798     UnNeg,
 799 }
 800
 801 impl UnOp {
 802     pub fn as_str(self) -> &'static str {
 803         match self {
 804             UnDeref => "*",
 805             UnNot => "!",
 806             UnNeg => "-",
 807         }
 808     }
 809
 810     /// Returns `true` if the unary operator takes its argument by value
 811     pub fn is_by_value(self) -> bool {
 812         match self {
 813             UnNeg | UnNot => true,
 814             _ => false,
 815         }
 816     }
 817 }
 818
 819 /// A statement
 820 pub type Stmt = Spanned<Stmt_>;
 821
 822 impl fmt::Debug for Stmt_ {
 823     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 824         // Sadness.
 825         let spanned = codemap::dummy_spanned(self.clone());
 826         write!(f,
 827                "stmt({}: {})",
 828                spanned.node.id(),
 829                print::to_string(print::NO_ANN, |s| s.print_stmt(&spanned)))
 830     }
 831 }
 832
 833 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 834 pub enum Stmt_ {
 835     /// Could be an item or a local (let) binding:
 836     StmtDecl(P<Decl>, NodeId),
 837
 838     /// Expr without trailing semi-colon (must have unit type):
 839     StmtExpr(P<Expr>, NodeId),
 840
 841     /// Expr with trailing semi-colon (may have any type):
 842     StmtSemi(P<Expr>, NodeId),
 843 }
 844
 845 impl Stmt_ {
 846     pub fn attrs(&self) -> &[Attribute] {
 847         match *self {
 848             StmtDecl(ref d, _) => d.node.attrs(),
 849             StmtExpr(ref e, _) |
 850             StmtSemi(ref e, _) => &e.attrs,
 851         }
 852     }
 853
 854     pub fn id(&self) -> NodeId {
 855         match *self {
 856             StmtDecl(_, id) => id,
 857             StmtExpr(_, id) => id,
 858             StmtSemi(_, id) => id,
 859         }
 860     }
 861 }
 862
 863 // FIXME (pending discussion of #1697, #2178...): local should really be
 864 // a refinement on pat.
 865 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`
 866 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 867 pub struct Local {
 868     pub pat: P<Pat>,
 869     pub ty: Option<P<Ty>>,
 870     /// Initializer expression to set the value, if any
 871     pub init: Option<P<Expr>>,
 872     pub id: NodeId,
 873     pub span: Span,
 874     pub attrs: ThinVec<Attribute>,
 875     pub source: LocalSource,
 876 }
 877
 878 pub type Decl = Spanned<Decl_>;
 879
 880 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 881 pub enum Decl_ {
 882     /// A local (let) binding:
 883     DeclLocal(P<Local>),
 884     /// An item binding:
 885     DeclItem(ItemId),
 886 }
 887
 888 impl Decl_ {
 889     pub fn attrs(&self) -> &[Attribute] {
 890         match *self {
 891             DeclLocal(ref l) => &l.attrs,
 892             DeclItem(_) => &[]
 893         }
 894     }
 895 }
 896
 897 /// represents one arm of a 'match'
 898 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 899 pub struct Arm {
 900     pub attrs: HirVec<Attribute>,
 901     pub pats: HirVec<P<Pat>>,
 902     pub guard: Option<P<Expr>>,
 903     pub body: P<Expr>,
 904 }
 905
 906 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 907 pub struct Field {
 908     pub name: Spanned<Name>,
 909     pub expr: P<Expr>,
 910     pub span: Span,
 911     pub is_shorthand: bool,
 912 }
 913
 914 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 915 pub enum BlockCheckMode {
 916     DefaultBlock,
 917     UnsafeBlock(UnsafeSource),
 918     PushUnsafeBlock(UnsafeSource),
 919     PopUnsafeBlock(UnsafeSource),
 920 }
 921
 922 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 923 pub enum UnsafeSource {
 924     CompilerGenerated,
 925     UserProvided,
 926 }
 927
 928 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug)]
 929 pub struct BodyId {
 930     pub node_id: NodeId,
 931 }
 932
 933 /// The body of a function or constant value.
 934 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 935 pub struct Body {
 936     pub arguments: HirVec<Arg>,
 937     pub value: Expr
 938 }
 939
 940 impl Body {
 941     pub fn id(&self) -> BodyId {
 942         BodyId {
 943             node_id: self.value.id
 944         }
 945     }
 946 }
 947
 948 /// An expression
 949 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 950 pub struct Expr {
 951     pub id: NodeId,
 952     pub span: Span,
 953     pub node: Expr_,
 954     pub attrs: ThinVec<Attribute>,
 955 }
 956
 957 impl fmt::Debug for Expr {
 958     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 959         write!(f, "expr({}: {})", self.id,
 960                print::to_string(print::NO_ANN, |s| s.print_expr(self)))
 961     }
 962 }
 963
 964 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 965 pub enum Expr_ {
 966     /// A `box x` expression.
 967     ExprBox(P<Expr>),
 968     /// An array (`[a, b, c, d]`)
 969     ExprArray(HirVec<Expr>),
 970     /// A function call
 971     ///
 972     /// The first field resolves to the function itself (usually an `ExprPath`),
 973     /// and the second field is the list of arguments
 974     ExprCall(P<Expr>, HirVec<Expr>),
 975     /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
 976     ///
 977     /// The `PathSegment`/`Span` represent the method name and its generic arguments
 978     /// (within the angle brackets).
 979     /// The first element of the vector of `Expr`s is the expression that evaluates
 980     /// to the object on which the method is being called on (the receiver),
 981     /// and the remaining elements are the rest of the arguments.
 982     /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
 983     /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
 984     ExprMethodCall(PathSegment, Span, HirVec<Expr>),
 985     /// A tuple (`(a, b, c ,d)`)
 986     ExprTup(HirVec<Expr>),
 987     /// A binary operation (For example: `a + b`, `a * b`)
 988     ExprBinary(BinOp, P<Expr>, P<Expr>),
 989     /// A unary operation (For example: `!x`, `*x`)
 990     ExprUnary(UnOp, P<Expr>),
 991     /// A literal (For example: `1`, `"foo"`)
 992     ExprLit(P<Lit>),
 993     /// A cast (`foo as f64`)
 994     ExprCast(P<Expr>, P<Ty>),
 995     ExprType(P<Expr>, P<Ty>),
 996     /// An `if` block, with an optional else block
 997     ///
 998     /// `if expr { expr } else { expr }`
 999     ExprIf(P<Expr>, P<Expr>, Option<P<Expr>>),
1000     /// A while loop, with an optional label
1001     ///
1002     /// `'label: while expr { block }`
1003     ExprWhile(P<Expr>, P<Block>, Option<Spanned<Name>>),
1004     /// Conditionless loop (can be exited with break, continue, or return)
1005     ///
1006     /// `'label: loop { block }`
1007     ExprLoop(P<Block>, Option<Spanned<Name>>, LoopSource),
1008     /// A `match` block, with a source that indicates whether or not it is
1009     /// the result of a desugaring, and if so, which kind.
1010     ExprMatch(P<Expr>, HirVec<Arm>, MatchSource),
1011     /// A closure (for example, `move |a, b, c| {a + b + c}`).
1012     ///
1013     /// The final span is the span of the argument block `|...|`
1014     ExprClosure(CaptureClause, P<FnDecl>, BodyId, Span),
1015     /// A block (`{ ... }`)
1016     ExprBlock(P<Block>),
1017
1018     /// An assignment (`a = foo()`)
1019     ExprAssign(P<Expr>, P<Expr>),
1020     /// An assignment with an operator
1021     ///
1022     /// For example, `a += 1`.
1023     ExprAssignOp(BinOp, P<Expr>, P<Expr>),
1024     /// Access of a named struct field (`obj.foo`)
1025     ExprField(P<Expr>, Spanned<Name>),
1026     /// Access of an unnamed field of a struct or tuple-struct
1027     ///
1028     /// For example, `foo.0`.
1029     ExprTupField(P<Expr>, Spanned<usize>),
1030     /// An indexing operation (`foo[2]`)
1031     ExprIndex(P<Expr>, P<Expr>),
1032
1033     /// Path to a definition, possibly containing lifetime or type parameters.
1034     ExprPath(QPath),
1035
1036     /// A referencing operation (`&a` or `&mut a`)
1037     ExprAddrOf(Mutability, P<Expr>),
1038     /// A `break`, with an optional label to break
1039     ExprBreak(Destination, Option<P<Expr>>),
1040     /// A `continue`, with an optional label
1041     ExprAgain(Destination),
1042     /// A `return`, with an optional value to be returned
1043     ExprRet(Option<P<Expr>>),
1044
1045     /// Inline assembly (from `asm!`), with its outputs and inputs.
1046     ExprInlineAsm(P<InlineAsm>, HirVec<Expr>, HirVec<Expr>),
1047
1048     /// A struct or struct-like variant literal expression.
1049     ///
1050     /// For example, `Foo {x: 1, y: 2}`, or
1051     /// `Foo {x: 1, .. base}`, where `base` is the `Option<Expr>`.
1052     ExprStruct(QPath, HirVec<Field>, Option<P<Expr>>),
1053
1054     /// An array literal constructed from one repeated element.
1055     ///
1056     /// For example, `[1; 5]`. The first expression is the element
1057     /// to be repeated; the second is the number of times to repeat it.
1058     ExprRepeat(P<Expr>, BodyId),
1059 }
1060
1061 /// Optionally `Self`-qualified value/type path or associated extension.
1062 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1063 pub enum QPath {
1064     /// Path to a definition, optionally "fully-qualified" with a `Self`
1065     /// type, if the path points to an associated item in a trait.
1066     ///
1067     /// E.g. an unqualified path like `Clone::clone` has `None` for `Self`,
1068     /// while `<Vec<T> as Clone>::clone` has `Some(Vec<T>)` for `Self`,
1069     /// even though they both have the same two-segment `Clone::clone` `Path`.
1070     Resolved(Option<P<Ty>>, P<Path>),
1071
1072     /// Type-related paths, e.g. `<T>::default` or `<T>::Output`.
1073     /// Will be resolved by type-checking to an associated item.
1074     ///
1075     /// UFCS source paths can desugar into this, with `Vec::new` turning into
1076     /// `<Vec>::new`, and `T::X::Y::method` into `<<<T>::X>::Y>::method`,
1077     /// the `X` and `Y` nodes each being a `TyPath(QPath::TypeRelative(..))`.
1078     TypeRelative(P<Ty>, P<PathSegment>)
1079 }
1080
1081 /// Hints at the original code for a let statement
1082 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1083 pub enum LocalSource {
1084     /// A `match _ { .. }`
1085     Normal,
1086     /// A desugared `for _ in _ { .. }` loop
1087     ForLoopDesugar,
1088 }
1089
1090 /// Hints at the original code for a `match _ { .. }`
1091 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1092 pub enum MatchSource {
1093     /// A `match _ { .. }`
1094     Normal,
1095     /// An `if let _ = _ { .. }` (optionally with `else { .. }`)
1096     IfLetDesugar {
1097         contains_else_clause: bool,
1098     },
1099     /// A `while let _ = _ { .. }` (which was desugared to a
1100     /// `loop { match _ { .. } }`)
1101     WhileLetDesugar,
1102     /// A desugared `for _ in _ { .. }` loop
1103     ForLoopDesugar,
1104     /// A desugared `?` operator
1105     TryDesugar,
1106 }
1107
1108 /// The loop type that yielded an ExprLoop
1109 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1110 pub enum LoopSource {
1111     /// A `loop { .. }` loop
1112     Loop,
1113     /// A `while let _ = _ { .. }` loop
1114     WhileLet,
1115     /// A `for _ in _ { .. }` loop
1116     ForLoop,
1117 }
1118
1119 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1120 pub enum LoopIdError {
1121     OutsideLoopScope,
1122     UnlabeledCfInWhileCondition,
1123     UnresolvedLabel,
1124 }
1125
1126 impl fmt::Display for LoopIdError {
1127     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1128         fmt::Display::fmt(match *self {
1129             LoopIdError::OutsideLoopScope => "not inside loop scope",
1130             LoopIdError::UnlabeledCfInWhileCondition =>
1131                 "unlabeled control flow (break or continue) in while condition",
1132             LoopIdError::UnresolvedLabel => "label not found",
1133         }, f)
1134     }
1135 }
1136
1137 // FIXME(cramertj) this should use `Result` once master compiles w/ a vesion of Rust where
1138 // `Result` implements `Encodable`/`Decodable`
1139 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1140 pub enum LoopIdResult {
1141     Ok(NodeId),
1142     Err(LoopIdError),
1143 }
1144 impl Into<Result<NodeId, LoopIdError>> for LoopIdResult {
1145     fn into(self) -> Result<NodeId, LoopIdError> {
1146         match self {
1147             LoopIdResult::Ok(ok) => Ok(ok),
1148             LoopIdResult::Err(err) => Err(err),
1149         }
1150     }
1151 }
1152 impl From<Result<NodeId, LoopIdError>> for LoopIdResult {
1153     fn from(res: Result<NodeId, LoopIdError>) -> Self {
1154         match res {
1155             Ok(ok) => LoopIdResult::Ok(ok),
1156             Err(err) => LoopIdResult::Err(err),
1157         }
1158     }
1159 }
1160
1161 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1162 pub enum ScopeTarget {
1163     Block(NodeId),
1164     Loop(LoopIdResult),
1165 }
1166
1167 impl ScopeTarget {
1168     pub fn opt_id(self) -> Option<NodeId> {
1169         match self {
1170             ScopeTarget::Block(node_id) |
1171             ScopeTarget::Loop(LoopIdResult::Ok(node_id)) => Some(node_id),
1172             ScopeTarget::Loop(LoopIdResult::Err(_)) => None,
1173         }
1174     }
1175 }
1176
1177 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1178 pub struct Destination {
1179     // This is `Some(_)` iff there is an explicit user-specified `label
1180     pub ident: Option<Spanned<Ident>>,
1181
1182     // These errors are caught and then reported during the diagnostics pass in
1183     // librustc_passes/loops.rs
1184     pub target_id: ScopeTarget,
1185 }
1186
1187 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1188 pub enum CaptureClause {
1189     CaptureByValue,
1190     CaptureByRef,
1191 }
1192
1193 // NB: If you change this, you'll probably want to change the corresponding
1194 // type structure in middle/ty.rs as well.
1195 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1196 pub struct MutTy {
1197     pub ty: P<Ty>,
1198     pub mutbl: Mutability,
1199 }
1200
1201 /// Represents a method's signature in a trait declaration or implementation.
1202 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1203 pub struct MethodSig {
1204     pub unsafety: Unsafety,
1205     pub constness: Constness,
1206     pub abi: Abi,
1207     pub decl: P<FnDecl>,
1208     pub generics: Generics,
1209 }
1210
1211 // The bodies for items are stored "out of line", in a separate
1212 // hashmap in the `Crate`. Here we just record the node-id of the item
1213 // so it can fetched later.
1214 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug)]
1215 pub struct TraitItemId {
1216     pub node_id: NodeId,
1217 }
1218
1219 /// Represents an item declaration within a trait declaration,
1220 /// possibly including a default implementation. A trait item is
1221 /// either required (meaning it doesn't have an implementation, just a
1222 /// signature) or provided (meaning it has a default implementation).
1223 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1224 pub struct TraitItem {
1225     pub id: NodeId,
1226     pub name: Name,
1227     pub attrs: HirVec<Attribute>,
1228     pub node: TraitItemKind,
1229     pub span: Span,
1230 }
1231
1232 /// A trait method's body (or just argument names).
1233 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1234 pub enum TraitMethod {
1235     /// No default body in the trait, just a signature.
1236     Required(HirVec<Spanned<Name>>),
1237
1238     /// Both signature and body are provided in the trait.
1239     Provided(BodyId),
1240 }
1241
1242 /// Represents a trait method or associated constant or type
1243 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1244 pub enum TraitItemKind {
1245     /// An associated constant with an optional value (otherwise `impl`s
1246     /// must contain a value)
1247     Const(P<Ty>, Option<BodyId>),
1248     /// A method with an optional body
1249     Method(MethodSig, TraitMethod),
1250     /// An associated type with (possibly empty) bounds and optional concrete
1251     /// type
1252     Type(TyParamBounds, Option<P<Ty>>),
1253 }
1254
1255 // The bodies for items are stored "out of line", in a separate
1256 // hashmap in the `Crate`. Here we just record the node-id of the item
1257 // so it can fetched later.
1258 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug)]
1259 pub struct ImplItemId {
1260     pub node_id: NodeId,
1261 }
1262
1263 /// Represents anything within an `impl` block
1264 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1265 pub struct ImplItem {
1266     pub id: NodeId,
1267     pub name: Name,
1268     pub vis: Visibility,
1269     pub defaultness: Defaultness,
1270     pub attrs: HirVec<Attribute>,
1271     pub node: ImplItemKind,
1272     pub span: Span,
1273 }
1274
1275 /// Represents different contents within `impl`s
1276 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1277 pub enum ImplItemKind {
1278     /// An associated constant of the given type, set to the constant result
1279     /// of the expression
1280     Const(P<Ty>, BodyId),
1281     /// A method implementation with the given signature and body
1282     Method(MethodSig, BodyId),
1283     /// An associated type
1284     Type(P<Ty>),
1285 }
1286
1287 // Bind a type to an associated type: `A=Foo`.
1288 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1289 pub struct TypeBinding {
1290     pub id: NodeId,
1291     pub name: Name,
1292     pub ty: P<Ty>,
1293     pub span: Span,
1294 }
1295
1296
1297 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
1298 pub struct Ty {
1299     pub id: NodeId,
1300     pub node: Ty_,
1301     pub span: Span,
1302 }
1303
1304 impl fmt::Debug for Ty {
1305     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1306         write!(f, "type({})",
1307                print::to_string(print::NO_ANN, |s| s.print_type(self)))
1308     }
1309 }
1310
1311 /// Not represented directly in the AST, referred to by name through a ty_path.
1312 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1313 pub enum PrimTy {
1314     TyInt(IntTy),
1315     TyUint(UintTy),
1316     TyFloat(FloatTy),
1317     TyStr,
1318     TyBool,
1319     TyChar,
1320 }
1321
1322 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1323 pub struct BareFnTy {
1324     pub unsafety: Unsafety,
1325     pub abi: Abi,
1326     pub lifetimes: HirVec<LifetimeDef>,
1327     pub decl: P<FnDecl>,
1328 }
1329
1330 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1331 /// The different kinds of types recognized by the compiler
1332 pub enum Ty_ {
1333     /// A variable length slice (`[T]`)
1334     TySlice(P<Ty>),
1335     /// A fixed length array (`[T; n]`)
1336     TyArray(P<Ty>, BodyId),
1337     /// A raw pointer (`*const T` or `*mut T`)
1338     TyPtr(MutTy),
1339     /// A reference (`&'a T` or `&'a mut T`)
1340     TyRptr(Lifetime, MutTy),
1341     /// A bare function (e.g. `fn(usize) -> bool`)
1342     TyBareFn(P<BareFnTy>),
1343     /// The never type (`!`)
1344     TyNever,
1345     /// A tuple (`(A, B, C, D,...)`)
1346     TyTup(HirVec<P<Ty>>),
1347     /// A path to a type definition (`module::module::...::Type`), or an
1348     /// associated type, e.g. `<Vec<T> as Trait>::Type` or `<T>::Target`.
1349     ///
1350     /// Type parameters may be stored in each `PathSegment`.
1351     TyPath(QPath),
1352     /// A trait object type `Bound1 + Bound2 + Bound3`
1353     /// where `Bound` is a trait or a lifetime.
1354     TyTraitObject(HirVec<PolyTraitRef>, Lifetime),
1355     /// An `impl Bound1 + Bound2 + Bound3` type
1356     /// where `Bound` is a trait or a lifetime.
1357     TyImplTrait(TyParamBounds),
1358     /// Unused for now
1359     TyTypeof(BodyId),
1360     /// TyInfer means the type should be inferred instead of it having been
1361     /// specified. This can appear anywhere in a type.
1362     TyInfer,
1363     /// Placeholder for a type that has failed to be defined.
1364     TyErr,
1365 }
1366
1367 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1368 pub struct InlineAsmOutput {
1369     pub constraint: Symbol,
1370     pub is_rw: bool,
1371     pub is_indirect: bool,
1372 }
1373
1374 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1375 pub struct InlineAsm {
1376     pub asm: Symbol,
1377     pub asm_str_style: StrStyle,
1378     pub outputs: HirVec<InlineAsmOutput>,
1379     pub inputs: HirVec<Symbol>,
1380     pub clobbers: HirVec<Symbol>,
1381     pub volatile: bool,
1382     pub alignstack: bool,
1383     pub dialect: AsmDialect,
1384     pub ctxt: SyntaxContext,
1385 }
1386
1387 /// represents an argument in a function header
1388 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1389 pub struct Arg {
1390     pub pat: P<Pat>,
1391     pub id: NodeId,
1392 }
1393
1394 /// Represents the header (not the body) of a function declaration
1395 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1396 pub struct FnDecl {
1397     pub inputs: HirVec<P<Ty>>,
1398     pub output: FunctionRetTy,
1399     pub variadic: bool,
1400     /// True if this function has an `self`, `&self` or `&mut self` receiver
1401     /// (but not a `self: Xxx` one).
1402     pub has_implicit_self: bool,
1403 }
1404
1405 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1406 pub enum Unsafety {
1407     Unsafe,
1408     Normal,
1409 }
1410
1411 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1412 pub enum Constness {
1413     Const,
1414     NotConst,
1415 }
1416
1417 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1418 pub enum Defaultness {
1419     Default { has_value: bool },
1420     Final,
1421 }
1422
1423 impl Defaultness {
1424     pub fn has_value(&self) -> bool {
1425         match *self {
1426             Defaultness::Default { has_value, .. } => has_value,
1427             Defaultness::Final => true,
1428         }
1429     }
1430
1431     pub fn is_final(&self) -> bool {
1432         *self == Defaultness::Final
1433     }
1434
1435     pub fn is_default(&self) -> bool {
1436         match *self {
1437             Defaultness::Default { .. } => true,
1438             _ => false,
1439         }
1440     }
1441 }
1442
1443 impl fmt::Display for Unsafety {
1444     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1445         fmt::Display::fmt(match *self {
1446                               Unsafety::Normal => "normal",
1447                               Unsafety::Unsafe => "unsafe",
1448                           },
1449                           f)
1450     }
1451 }
1452
1453 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
1454 pub enum ImplPolarity {
1455     /// `impl Trait for Type`
1456     Positive,
1457     /// `impl !Trait for Type`
1458     Negative,
1459 }
1460
1461 impl fmt::Debug for ImplPolarity {
1462     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1463         match *self {
1464             ImplPolarity::Positive => "positive".fmt(f),
1465             ImplPolarity::Negative => "negative".fmt(f),
1466         }
1467     }
1468 }
1469
1470
1471 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1472 pub enum FunctionRetTy {
1473     /// Return type is not specified.
1474     ///
1475     /// Functions default to `()` and
1476     /// closures default to inference. Span points to where return
1477     /// type would be inserted.
1478     DefaultReturn(Span),
1479     /// Everything else
1480     Return(P<Ty>),
1481 }
1482
1483 impl FunctionRetTy {
1484     pub fn span(&self) -> Span {
1485         match *self {
1486             DefaultReturn(span) => span,
1487             Return(ref ty) => ty.span,
1488         }
1489     }
1490 }
1491
1492 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1493 pub struct Mod {
1494     /// A span from the first token past `{` to the last token until `}`.
1495     /// For `mod foo;`, the inner span ranges from the first token
1496     /// to the last token in the external file.
1497     pub inner: Span,
1498     pub item_ids: HirVec<ItemId>,
1499 }
1500
1501 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1502 pub struct ForeignMod {
1503     pub abi: Abi,
1504     pub items: HirVec<ForeignItem>,
1505 }
1506
1507 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1508 pub struct GlobalAsm {
1509     pub asm: Symbol,
1510     pub ctxt: SyntaxContext,
1511 }
1512
1513 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1514 pub struct EnumDef {
1515     pub variants: HirVec<Variant>,
1516 }
1517
1518 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1519 pub struct Variant_ {
1520     pub name: Name,
1521     pub attrs: HirVec<Attribute>,
1522     pub data: VariantData,
1523     /// Explicit discriminant, eg `Foo = 1`
1524     pub disr_expr: Option<BodyId>,
1525 }
1526
1527 pub type Variant = Spanned<Variant_>;
1528
1529 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1530 pub enum UseKind {
1531     /// One import, e.g. `use foo::bar` or `use foo::bar as baz`.
1532     /// Also produced for each element of a list `use`, e.g.
1533     // `use foo::{a, b}` lowers to `use foo::a; use foo::b;`.
1534     Single,
1535
1536     /// Glob import, e.g. `use foo::*`.
1537     Glob,
1538
1539     /// Degenerate list import, e.g. `use foo::{a, b}` produces
1540     /// an additional `use foo::{}` for performing checks such as
1541     /// unstable feature gating. May be removed in the future.
1542     ListStem,
1543 }
1544
1545 /// TraitRef's appear in impls.
1546 ///
1547 /// resolve maps each TraitRef's ref_id to its defining trait; that's all
1548 /// that the ref_id is for. Note that ref_id's value is not the NodeId of the
1549 /// trait being referred to but just a unique NodeId that serves as a key
1550 /// within the DefMap.
1551 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1552 pub struct TraitRef {
1553     pub path: Path,
1554     pub ref_id: NodeId,
1555 }
1556
1557 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1558 pub struct PolyTraitRef {
1559     /// The `'a` in `<'a> Foo<&'a T>`
1560     pub bound_lifetimes: HirVec<LifetimeDef>,
1561
1562     /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`
1563     pub trait_ref: TraitRef,
1564
1565     pub span: Span,
1566 }
1567
1568 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1569 pub enum Visibility {
1570     Public,
1571     Crate,
1572     Restricted { path: P<Path>, id: NodeId },
1573     Inherited,
1574 }
1575
1576 impl Visibility {
1577     pub fn is_pub_restricted(&self) -> bool {
1578         use self::Visibility::*;
1579         match self {
1580             &Public |
1581             &Inherited => false,
1582             &Crate |
1583             &Restricted { .. } => true,
1584         }
1585     }
1586 }
1587
1588 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1589 pub struct StructField {
1590     pub span: Span,
1591     pub name: Name,
1592     pub vis: Visibility,
1593     pub id: NodeId,
1594     pub ty: P<Ty>,
1595     pub attrs: HirVec<Attribute>,
1596 }
1597
1598 impl StructField {
1599     // Still necessary in couple of places
1600     pub fn is_positional(&self) -> bool {
1601         let first = self.name.as_str().as_bytes()[0];
1602         first >= b'0' && first <= b'9'
1603     }
1604 }
1605
1606 /// Fields and Ids of enum variants and structs
1607 ///
1608 /// For enum variants: `NodeId` represents both an Id of the variant itself (relevant for all
1609 /// variant kinds) and an Id of the variant's constructor (not relevant for `Struct`-variants).
1610 /// One shared Id can be successfully used for these two purposes.
1611 /// Id of the whole enum lives in `Item`.
1612 ///
1613 /// For structs: `NodeId` represents an Id of the structure's constructor, so it is not actually
1614 /// used for `Struct`-structs (but still presents). Structures don't have an analogue of "Id of
1615 /// the variant itself" from enum variants.
1616 /// Id of the whole struct lives in `Item`.
1617 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1618 pub enum VariantData {
1619     Struct(HirVec<StructField>, NodeId),
1620     Tuple(HirVec<StructField>, NodeId),
1621     Unit(NodeId),
1622 }
1623
1624 impl VariantData {
1625     pub fn fields(&self) -> &[StructField] {
1626         match *self {
1627             VariantData::Struct(ref fields, _) | VariantData::Tuple(ref fields, _) => fields,
1628             _ => &[],
1629         }
1630     }
1631     pub fn id(&self) -> NodeId {
1632         match *self {
1633             VariantData::Struct(_, id) | VariantData::Tuple(_, id) | VariantData::Unit(id) => id,
1634         }
1635     }
1636     pub fn is_struct(&self) -> bool {
1637         if let VariantData::Struct(..) = *self {
1638             true
1639         } else {
1640             false
1641         }
1642     }
1643     pub fn is_tuple(&self) -> bool {
1644         if let VariantData::Tuple(..) = *self {
1645             true
1646         } else {
1647             false
1648         }
1649     }
1650     pub fn is_unit(&self) -> bool {
1651         if let VariantData::Unit(..) = *self {
1652             true
1653         } else {
1654             false
1655         }
1656     }
1657 }
1658
1659 // The bodies for items are stored "out of line", in a separate
1660 // hashmap in the `Crate`. Here we just record the node-id of the item
1661 // so it can fetched later.
1662 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1663 pub struct ItemId {
1664     pub id: NodeId,
1665 }
1666
1667 /// An item
1668 ///
1669 /// The name might be a dummy name in case of anonymous items
1670 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1671 pub struct Item {
1672     pub name: Name,
1673     pub attrs: HirVec<Attribute>,
1674     pub id: NodeId,
1675     pub node: Item_,
1676     pub vis: Visibility,
1677     pub span: Span,
1678 }
1679
1680 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1681 pub enum Item_ {
1682     /// An`extern crate` item, with optional original crate name,
1683     ///
1684     /// e.g. `extern crate foo` or `extern crate foo_bar as foo`
1685     ItemExternCrate(Option<Name>),
1686
1687     /// `use foo::bar::*;` or `use foo::bar::baz as quux;`
1688     ///
1689     /// or just
1690     ///
1691     /// `use foo::bar::baz;` (with `as baz` implicitly on the right)
1692     ItemUse(P<Path>, UseKind),
1693
1694     /// A `static` item
1695     ItemStatic(P<Ty>, Mutability, BodyId),
1696     /// A `const` item
1697     ItemConst(P<Ty>, BodyId),
1698     /// A function declaration
1699     ItemFn(P<FnDecl>, Unsafety, Constness, Abi, Generics, BodyId),
1700     /// A module
1701     ItemMod(Mod),
1702     /// An external module
1703     ItemForeignMod(ForeignMod),
1704     /// Module-level inline assembly (from global_asm!)
1705     ItemGlobalAsm(P<GlobalAsm>),
1706     /// A type alias, e.g. `type Foo = Bar<u8>`
1707     ItemTy(P<Ty>, Generics),
1708     /// An enum definition, e.g. `enum Foo<A, B> {C<A>, D<B>}`
1709     ItemEnum(EnumDef, Generics),
1710     /// A struct definition, e.g. `struct Foo<A> {x: A}`
1711     ItemStruct(VariantData, Generics),
1712     /// A union definition, e.g. `union Foo<A, B> {x: A, y: B}`
1713     ItemUnion(VariantData, Generics),
1714     /// Represents a Trait Declaration
1715     ItemTrait(Unsafety, Generics, TyParamBounds, HirVec<TraitItemRef>),
1716
1717     // Default trait implementations
1718     ///
1719     /// `impl Trait for .. {}`
1720     ItemDefaultImpl(Unsafety, TraitRef),
1721     /// An implementation, eg `impl<A> Trait for Foo { .. }`
1722     ItemImpl(Unsafety,
1723              ImplPolarity,
1724              Defaultness,
1725              Generics,
1726              Option<TraitRef>, // (optional) trait this impl implements
1727              P<Ty>, // self
1728              HirVec<ImplItemRef>),
1729 }
1730
1731 impl Item_ {
1732     pub fn descriptive_variant(&self) -> &str {
1733         match *self {
1734             ItemExternCrate(..) => "extern crate",
1735             ItemUse(..) => "use",
1736             ItemStatic(..) => "static item",
1737             ItemConst(..) => "constant item",
1738             ItemFn(..) => "function",
1739             ItemMod(..) => "module",
1740             ItemForeignMod(..) => "foreign module",
1741             ItemGlobalAsm(..) => "global asm",
1742             ItemTy(..) => "type alias",
1743             ItemEnum(..) => "enum",
1744             ItemStruct(..) => "struct",
1745             ItemUnion(..) => "union",
1746             ItemTrait(..) => "trait",
1747             ItemImpl(..) |
1748             ItemDefaultImpl(..) => "item",
1749         }
1750     }
1751 }
1752
1753 /// A reference from an trait to one of its associated items. This
1754 /// contains the item's id, naturally, but also the item's name and
1755 /// some other high-level details (like whether it is an associated
1756 /// type or method, and whether it is public). This allows other
1757 /// passes to find the impl they want without loading the id (which
1758 /// means fewer edges in the incremental compilation graph).
1759 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1760 pub struct TraitItemRef {
1761     pub id: TraitItemId,
1762     pub name: Name,
1763     pub kind: AssociatedItemKind,
1764     pub span: Span,
1765     pub defaultness: Defaultness,
1766 }
1767
1768 /// A reference from an impl to one of its associated items. This
1769 /// contains the item's id, naturally, but also the item's name and
1770 /// some other high-level details (like whether it is an associated
1771 /// type or method, and whether it is public). This allows other
1772 /// passes to find the impl they want without loading the id (which
1773 /// means fewer edges in the incremental compilation graph).
1774 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1775 pub struct ImplItemRef {
1776     pub id: ImplItemId,
1777     pub name: Name,
1778     pub kind: AssociatedItemKind,
1779     pub span: Span,
1780     pub vis: Visibility,
1781     pub defaultness: Defaultness,
1782 }
1783
1784 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1785 pub enum AssociatedItemKind {
1786     Const,
1787     Method { has_self: bool },
1788     Type,
1789 }
1790
1791 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1792 pub struct ForeignItem {
1793     pub name: Name,
1794     pub attrs: HirVec<Attribute>,
1795     pub node: ForeignItem_,
1796     pub id: NodeId,
1797     pub span: Span,
1798     pub vis: Visibility,
1799 }
1800
1801 /// An item within an `extern` block
1802 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1803 pub enum ForeignItem_ {
1804     /// A foreign function
1805     ForeignItemFn(P<FnDecl>, HirVec<Spanned<Name>>, Generics),
1806     /// A foreign static item (`static ext: u8`), with optional mutability
1807     /// (the boolean is true when mutable)
1808     ForeignItemStatic(P<Ty>, bool),
1809 }
1810
1811 impl ForeignItem_ {
1812     pub fn descriptive_variant(&self) -> &str {
1813         match *self {
1814             ForeignItemFn(..) => "foreign function",
1815             ForeignItemStatic(..) => "foreign static item",
1816         }
1817     }
1818 }
1819
1820 /// A free variable referred to in a function.
1821 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
1822 pub struct Freevar {
1823     /// The variable being accessed free.
1824     pub def: Def,
1825
1826     // First span where it is accessed (there can be multiple).
1827     pub span: Span
1828 }
1829
1830 pub type FreevarMap = NodeMap<Vec<Freevar>>;
1831
1832 pub type CaptureModeMap = NodeMap<CaptureClause>;
1833
1834 #[derive(Clone, Debug)]
1835 pub struct TraitCandidate {
1836     pub def_id: DefId,
1837     pub import_id: Option<NodeId>,
1838 }
1839
1840 // Trait method resolution
1841 pub type TraitMap = NodeMap<Vec<TraitCandidate>>;
1842
1843 // Map from the NodeId of a glob import to a list of items which are actually
1844 // imported.
1845 pub type GlobMap = NodeMap<FxHashSet<Name>>;