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::BinOp_::*;
  14 pub use self::BlockCheckMode::*;
  15 pub use self::CaptureClause::*;
  16 pub use self::Decl_::*;
  17 pub use self::Expr_::*;
  18 pub use self::FunctionRetTy::*;
  19 pub use self::ForeignItem_::*;
  20 pub use self::Item_::*;
  21 pub use self::Mutability::*;
  22 pub use self::PrimTy::*;
  23 pub use self::Stmt_::*;
  24 pub use self::Ty_::*;
  25 pub use self::TyParamBound::*;
  26 pub use self::UnOp::*;
  27 pub use self::UnsafeSource::*;
  28 pub use self::Visibility::{Public, Inherited};
  29
  30 use hir::def::Def;
  31 use hir::def_id::{DefId, DefIndex, CRATE_DEF_INDEX};
  32 use util::nodemap::{NodeMap, FxHashSet};
  33
  34 use syntax_pos::{Span, DUMMY_SP};
  35 use syntax::codemap::{self, Spanned};
  36 use syntax::abi::Abi;
  37 use syntax::ast::{Ident, Name, NodeId, DUMMY_NODE_ID, AsmDialect};
  38 use syntax::ast::{Attribute, Lit, StrStyle, FloatTy, IntTy, UintTy, MetaItem};
  39 use syntax::ext::hygiene::SyntaxContext;
  40 use syntax::ptr::P;
  41 use syntax::symbol::{Symbol, keywords};
  42 use syntax::tokenstream::TokenStream;
  43 use syntax::util::ThinVec;
  44 use ty::AdtKind;
  45
  46 use rustc_data_structures::indexed_vec;
  47
  48 use serialize::{self, Encoder, Encodable, Decoder, Decodable};
  49 use std::collections::BTreeMap;
  50 use std::fmt;
  51
  52 /// HIR doesn't commit to a concrete storage type and has 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 the 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 in
  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 pub struct HirId {
  91     pub owner: DefIndex,
  92     pub local_id: ItemLocalId,
  93 }
  94
  95 impl serialize::UseSpecializedEncodable for HirId {
  96     fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
  97         let HirId {
  98             owner,
  99             local_id,
 100         } = *self;
 101
 102         owner.encode(s)?;
 103         local_id.encode(s)
 104     }
 105 }
 106
 107 impl serialize::UseSpecializedDecodable for HirId {
 108     fn default_decode<D: Decoder>(d: &mut D) -> Result<HirId, D::Error> {
 109         let owner = DefIndex::decode(d)?;
 110         let local_id = ItemLocalId::decode(d)?;
 111
 112         Ok(HirId {
 113             owner,
 114             local_id
 115         })
 116     }
 117 }
 118
 119
 120 /// An `ItemLocalId` uniquely identifies something within a given "item-like",
 121 /// that is within a hir::Item, hir::TraitItem, or hir::ImplItem. There is no
 122 /// guarantee that the numerical value of a given `ItemLocalId` corresponds to
 123 /// the node's position within the owning item in any way, but there is a
 124 /// guarantee that the `LocalItemId`s within an owner occupy a dense range of
 125 /// integers starting at zero, so a mapping that maps all or most nodes within
 126 /// an "item-like" to something else can be implement by a `Vec` instead of a
 127 /// tree or hash map.
 128 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Debug,
 129          RustcEncodable, RustcDecodable)]
 130 pub struct ItemLocalId(pub u32);
 131
 132 impl ItemLocalId {
 133     pub fn as_usize(&self) -> usize {
 134         self.0 as usize
 135     }
 136 }
 137
 138 impl indexed_vec::Idx for ItemLocalId {
 139     fn new(idx: usize) -> Self {
 140         debug_assert!((idx as u32) as usize == idx);
 141         ItemLocalId(idx as u32)
 142     }
 143
 144     fn index(self) -> usize {
 145         self.0 as usize
 146     }
 147 }
 148
 149 /// The `HirId` corresponding to CRATE_NODE_ID and CRATE_DEF_INDEX
 150 pub const CRATE_HIR_ID: HirId = HirId {
 151     owner: CRATE_DEF_INDEX,
 152     local_id: ItemLocalId(0)
 153 };
 154
 155 pub const DUMMY_HIR_ID: HirId = HirId {
 156     owner: CRATE_DEF_INDEX,
 157     local_id: DUMMY_ITEM_LOCAL_ID,
 158 };
 159
 160 pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId(!0);
 161
 162 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
 163 pub struct Lifetime {
 164     pub id: NodeId,
 165     pub span: Span,
 166
 167     /// Either "'a", referring to a named lifetime definition,
 168     /// or "" (aka keywords::Invalid), for elision placeholders.
 169     ///
 170     /// HIR lowering inserts these placeholders in type paths that
 171     /// refer to type definitions needing lifetime parameters,
 172     /// `&T` and `&mut T`, and trait objects without `... + 'a`.
 173     pub name: LifetimeName,
 174 }
 175
 176 #[derive(Debug, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
 177 pub enum LifetimeName {
 178     Implicit,
 179     Underscore,
 180     Static,
 181     Name(Name),
 182 }
 183
 184 impl LifetimeName {
 185     pub fn name(&self) -> Name {
 186         use self::LifetimeName::*;
 187         match *self {
 188             Implicit => keywords::Invalid.name(),
 189             Underscore => Symbol::intern("'_"),
 190             Static => keywords::StaticLifetime.name(),
 191             Name(name) => name,
 192         }
 193     }
 194 }
 195
 196 impl fmt::Debug for Lifetime {
 197     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 198         write!(f,
 199                "lifetime({}: {})",
 200                self.id,
 201                print::to_string(print::NO_ANN, |s| s.print_lifetime(self)))
 202     }
 203 }
 204
 205 impl Lifetime {
 206     pub fn is_elided(&self) -> bool {
 207         use self::LifetimeName::*;
 208         match self.name {
 209             Implicit | Underscore => true,
 210             Static | Name(_) => false,
 211         }
 212     }
 213
 214     pub fn is_static(&self) -> bool {
 215         self.name == LifetimeName::Static
 216     }
 217 }
 218
 219 /// A lifetime definition, eg `'a: 'b+'c+'d`
 220 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 221 pub struct LifetimeDef {
 222     pub lifetime: Lifetime,
 223     pub bounds: HirVec<Lifetime>,
 224     pub pure_wrt_drop: bool,
 225 }
 226
 227 /// A "Path" is essentially Rust's notion of a name; for instance:
 228 /// std::cmp::PartialEq  .  It's represented as a sequence of identifiers,
 229 /// along with a bunch of supporting information.
 230 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 231 pub struct Path {
 232     pub span: Span,
 233     /// The definition that the path resolved to.
 234     pub def: Def,
 235     /// The segments in the path: the things separated by `::`.
 236     pub segments: HirVec<PathSegment>,
 237 }
 238
 239 impl Path {
 240     pub fn is_global(&self) -> bool {
 241         !self.segments.is_empty() && self.segments[0].name == keywords::CrateRoot.name()
 242     }
 243 }
 244
 245 impl fmt::Debug for Path {
 246     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 247         write!(f, "path({})",
 248                print::to_string(print::NO_ANN, |s| s.print_path(self, false)))
 249     }
 250 }
 251
 252 /// A segment of a path: an identifier, an optional lifetime, and a set of
 253 /// types.
 254 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 255 pub struct PathSegment {
 256     /// The identifier portion of this path segment.
 257     pub name: Name,
 258
 259     /// Type/lifetime parameters attached to this path. They come in
 260     /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`. Note that
 261     /// this is more than just simple syntactic sugar; the use of
 262     /// parens affects the region binding rules, so we preserve the
 263     /// distinction.
 264     pub parameters: Option<P<PathParameters>>,
 265
 266     /// Whether to infer remaining type parameters, if any.
 267     /// This only applies to expression and pattern paths, and
 268     /// out of those only the segments with no type parameters
 269     /// to begin with, e.g. `Vec::new` is `<Vec<..>>::new::<..>`.
 270     pub infer_types: bool,
 271 }
 272
 273 impl PathSegment {
 274     /// Convert an identifier to the corresponding segment.
 275     pub fn from_name(name: Name) -> PathSegment {
 276         PathSegment {
 277             name,
 278             infer_types: true,
 279             parameters: None
 280         }
 281     }
 282
 283     pub fn new(name: Name, parameters: PathParameters, infer_types: bool) -> Self {
 284         PathSegment {
 285             name,
 286             infer_types,
 287             parameters: if parameters.is_empty() {
 288                 None
 289             } else {
 290                 Some(P(parameters))
 291             }
 292         }
 293     }
 294
 295     // FIXME: hack required because you can't create a static
 296     // PathParameters, so you can't just return a &PathParameters.
 297     pub fn with_parameters<F, R>(&self, f: F) -> R
 298         where F: FnOnce(&PathParameters) -> R
 299     {
 300         let dummy = PathParameters::none();
 301         f(if let Some(ref params) = self.parameters {
 302             &params
 303         } else {
 304             &dummy
 305         })
 306     }
 307 }
 308
 309 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 310 pub struct PathParameters {
 311     /// The lifetime parameters for this path segment.
 312     pub lifetimes: HirVec<Lifetime>,
 313     /// The type parameters for this path segment, if present.
 314     pub types: HirVec<P<Ty>>,
 315     /// Bindings (equality constraints) on associated types, if present.
 316     /// E.g., `Foo<A=Bar>`.
 317     pub bindings: HirVec<TypeBinding>,
 318     /// Were parameters written in parenthesized form `Fn(T) -> U`?
 319     /// This is required mostly for pretty-printing and diagnostics,
 320     /// but also for changing lifetime elision rules to be "function-like".
 321     pub parenthesized: bool,
 322 }
 323
 324 impl PathParameters {
 325     pub fn none() -> Self {
 326         Self {
 327             lifetimes: HirVec::new(),
 328             types: HirVec::new(),
 329             bindings: HirVec::new(),
 330             parenthesized: false,
 331         }
 332     }
 333
 334     pub fn is_empty(&self) -> bool {
 335         self.lifetimes.is_empty() && self.types.is_empty() &&
 336             self.bindings.is_empty() && !self.parenthesized
 337     }
 338
 339     pub fn inputs(&self) -> &[P<Ty>] {
 340         if self.parenthesized {
 341             if let Some(ref ty) = self.types.get(0) {
 342                 if let TyTup(ref tys) = ty.node {
 343                     return tys;
 344                 }
 345             }
 346         }
 347         bug!("PathParameters::inputs: not a `Fn(T) -> U`");
 348     }
 349 }
 350
 351 /// The AST represents all type param bounds as types.
 352 /// typeck::collect::compute_bounds matches these against
 353 /// the "special" built-in traits (see middle::lang_items) and
 354 /// detects Copy, Send and Sync.
 355 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 356 pub enum TyParamBound {
 357     TraitTyParamBound(PolyTraitRef, TraitBoundModifier),
 358     RegionTyParamBound(Lifetime),
 359 }
 360
 361 /// A modifier on a bound, currently this is only used for `?Sized`, where the
 362 /// modifier is `Maybe`. Negative bounds should also be handled here.
 363 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 364 pub enum TraitBoundModifier {
 365     None,
 366     Maybe,
 367 }
 368
 369 pub type TyParamBounds = HirVec<TyParamBound>;
 370
 371 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 372 pub struct TyParam {
 373     pub name: Name,
 374     pub id: NodeId,
 375     pub bounds: TyParamBounds,
 376     pub default: Option<P<Ty>>,
 377     pub span: Span,
 378     pub pure_wrt_drop: bool,
 379     pub synthetic: Option<SyntheticTyParamKind>,
 380 }
 381
 382 /// Represents lifetimes and type parameters attached to a declaration
 383 /// of a function, enum, trait, etc.
 384 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 385 pub struct Generics {
 386     pub lifetimes: HirVec<LifetimeDef>,
 387     pub ty_params: HirVec<TyParam>,
 388     pub where_clause: WhereClause,
 389     pub span: Span,
 390 }
 391
 392 impl Generics {
 393     pub fn empty() -> Generics {
 394         Generics {
 395             lifetimes: HirVec::new(),
 396             ty_params: HirVec::new(),
 397             where_clause: WhereClause {
 398                 id: DUMMY_NODE_ID,
 399                 predicates: HirVec::new(),
 400             },
 401             span: DUMMY_SP,
 402         }
 403     }
 404
 405     pub fn is_lt_parameterized(&self) -> bool {
 406         !self.lifetimes.is_empty()
 407     }
 408
 409     pub fn is_type_parameterized(&self) -> bool {
 410         !self.ty_params.is_empty()
 411     }
 412
 413     pub fn is_parameterized(&self) -> bool {
 414         self.is_lt_parameterized() || self.is_type_parameterized()
 415     }
 416 }
 417
 418 pub enum UnsafeGeneric {
 419     Region(LifetimeDef, &'static str),
 420     Type(TyParam, &'static str),
 421 }
 422
 423 impl UnsafeGeneric {
 424     pub fn attr_name(&self) -> &'static str {
 425         match *self {
 426             UnsafeGeneric::Region(_, s) => s,
 427             UnsafeGeneric::Type(_, s) => s,
 428         }
 429     }
 430 }
 431
 432 impl Generics {
 433     pub fn carries_unsafe_attr(&self) -> Option<UnsafeGeneric> {
 434         for r in &self.lifetimes {
 435             if r.pure_wrt_drop {
 436                 return Some(UnsafeGeneric::Region(r.clone(), "may_dangle"));
 437             }
 438         }
 439         for t in &self.ty_params {
 440             if t.pure_wrt_drop {
 441                 return Some(UnsafeGeneric::Type(t.clone(), "may_dangle"));
 442             }
 443         }
 444         return None;
 445     }
 446 }
 447
 448 /// Synthetic Type Parameters are converted to an other form during lowering, this allows
 449 /// to track the original form they had. Usefull for error messages.
 450 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 451 pub enum SyntheticTyParamKind {
 452     ImplTrait
 453 }
 454
 455 /// A `where` clause in a definition
 456 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 457 pub struct WhereClause {
 458     pub id: NodeId,
 459     pub predicates: HirVec<WherePredicate>,
 460 }
 461
 462 /// A single predicate in a `where` clause
 463 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 464 pub enum WherePredicate {
 465     /// A type binding, eg `for<'c> Foo: Send+Clone+'c`
 466     BoundPredicate(WhereBoundPredicate),
 467     /// A lifetime predicate, e.g. `'a: 'b+'c`
 468     RegionPredicate(WhereRegionPredicate),
 469     /// An equality predicate (unsupported)
 470     EqPredicate(WhereEqPredicate),
 471 }
 472
 473 /// A type bound, eg `for<'c> Foo: Send+Clone+'c`
 474 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 475 pub struct WhereBoundPredicate {
 476     pub span: Span,
 477     /// Any lifetimes from a `for` binding
 478     pub bound_lifetimes: HirVec<LifetimeDef>,
 479     /// The type being bounded
 480     pub bounded_ty: P<Ty>,
 481     /// Trait and lifetime bounds (`Clone+Send+'static`)
 482     pub bounds: TyParamBounds,
 483 }
 484
 485 /// A lifetime predicate, e.g. `'a: 'b+'c`
 486 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 487 pub struct WhereRegionPredicate {
 488     pub span: Span,
 489     pub lifetime: Lifetime,
 490     pub bounds: HirVec<Lifetime>,
 491 }
 492
 493 /// An equality predicate (unsupported), e.g. `T=int`
 494 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 495 pub struct WhereEqPredicate {
 496     pub id: NodeId,
 497     pub span: Span,
 498     pub lhs_ty: P<Ty>,
 499     pub rhs_ty: P<Ty>,
 500 }
 501
 502 pub type CrateConfig = HirVec<P<MetaItem>>;
 503
 504 /// The top-level data structure that stores the entire contents of
 505 /// the crate currently being compiled.
 506 ///
 507 /// For more details, see [the module-level README](README.md).
 508 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
 509 pub struct Crate {
 510     pub module: Mod,
 511     pub attrs: HirVec<Attribute>,
 512     pub span: Span,
 513     pub exported_macros: HirVec<MacroDef>,
 514
 515     // NB: We use a BTreeMap here so that `visit_all_items` iterates
 516     // over the ids in increasing order. In principle it should not
 517     // matter what order we visit things in, but in *practice* it
 518     // does, because it can affect the order in which errors are
 519     // detected, which in turn can make compile-fail tests yield
 520     // slightly different results.
 521     pub items: BTreeMap<NodeId, Item>,
 522
 523     pub trait_items: BTreeMap<TraitItemId, TraitItem>,
 524     pub impl_items: BTreeMap<ImplItemId, ImplItem>,
 525     pub bodies: BTreeMap<BodyId, Body>,
 526     pub trait_impls: BTreeMap<DefId, Vec<NodeId>>,
 527     pub trait_auto_impl: BTreeMap<DefId, NodeId>,
 528
 529     /// A list of the body ids written out in the order in which they
 530     /// appear in the crate. If you're going to process all the bodies
 531     /// in the crate, you should iterate over this list rather than the keys
 532     /// of bodies.
 533     pub body_ids: Vec<BodyId>,
 534 }
 535
 536 impl Crate {
 537     pub fn item(&self, id: NodeId) -> &Item {
 538         &self.items[&id]
 539     }
 540
 541     pub fn trait_item(&self, id: TraitItemId) -> &TraitItem {
 542         &self.trait_items[&id]
 543     }
 544
 545     pub fn impl_item(&self, id: ImplItemId) -> &ImplItem {
 546         &self.impl_items[&id]
 547     }
 548
 549     /// Visits all items in the crate in some deterministic (but
 550     /// unspecified) order. If you just need to process every item,
 551     /// but don't care about nesting, this method is the best choice.
 552     ///
 553     /// If you do care about nesting -- usually because your algorithm
 554     /// follows lexical scoping rules -- then you want a different
 555     /// approach. You should override `visit_nested_item` in your
 556     /// visitor and then call `intravisit::walk_crate` instead.
 557     pub fn visit_all_item_likes<'hir, V>(&'hir self, visitor: &mut V)
 558         where V: itemlikevisit::ItemLikeVisitor<'hir>
 559     {
 560         for (_, item) in &self.items {
 561             visitor.visit_item(item);
 562         }
 563
 564         for (_, trait_item) in &self.trait_items {
 565             visitor.visit_trait_item(trait_item);
 566         }
 567
 568         for (_, impl_item) in &self.impl_items {
 569             visitor.visit_impl_item(impl_item);
 570         }
 571     }
 572
 573     pub fn body(&self, id: BodyId) -> &Body {
 574         &self.bodies[&id]
 575     }
 576 }
 577
 578 /// A macro definition, in this crate or imported from another.
 579 ///
 580 /// Not parsed directly, but created on macro import or `macro_rules!` expansion.
 581 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 582 pub struct MacroDef {
 583     pub name: Name,
 584     pub vis: Visibility,
 585     pub attrs: HirVec<Attribute>,
 586     pub id: NodeId,
 587     pub span: Span,
 588     pub body: TokenStream,
 589     pub legacy: bool,
 590 }
 591
 592 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 593 pub struct Block {
 594     /// Statements in a block
 595     pub stmts: HirVec<Stmt>,
 596     /// An expression at the end of the block
 597     /// without a semicolon, if any
 598     pub expr: Option<P<Expr>>,
 599     pub id: NodeId,
 600     pub hir_id: HirId,
 601     /// Distinguishes between `unsafe { ... }` and `{ ... }`
 602     pub rules: BlockCheckMode,
 603     pub span: Span,
 604     /// If true, then there may exist `break 'a` values that aim to
 605     /// break out of this block early. As of this writing, this is not
 606     /// currently permitted in Rust itself, but it is generated as
 607     /// part of `catch` statements.
 608     pub targeted_by_break: bool,
 609 }
 610
 611 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 612 pub struct Pat {
 613     pub id: NodeId,
 614     pub hir_id: HirId,
 615     pub node: PatKind,
 616     pub span: Span,
 617 }
 618
 619 impl fmt::Debug for Pat {
 620     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 621         write!(f, "pat({}: {})", self.id,
 622                print::to_string(print::NO_ANN, |s| s.print_pat(self)))
 623     }
 624 }
 625
 626 impl Pat {
 627     // FIXME(#19596) this is a workaround, but there should be a better way
 628     fn walk_<G>(&self, it: &mut G) -> bool
 629         where G: FnMut(&Pat) -> bool
 630     {
 631         if !it(self) {
 632             return false;
 633         }
 634
 635         match self.node {
 636             PatKind::Binding(.., Some(ref p)) => p.walk_(it),
 637             PatKind::Struct(_, ref fields, _) => {
 638                 fields.iter().all(|field| field.node.pat.walk_(it))
 639             }
 640             PatKind::TupleStruct(_, ref s, _) | PatKind::Tuple(ref s, _) => {
 641                 s.iter().all(|p| p.walk_(it))
 642             }
 643             PatKind::Box(ref s) | PatKind::Ref(ref s, _) => {
 644                 s.walk_(it)
 645             }
 646             PatKind::Slice(ref before, ref slice, ref after) => {
 647                 before.iter().all(|p| p.walk_(it)) &&
 648                 slice.iter().all(|p| p.walk_(it)) &&
 649                 after.iter().all(|p| p.walk_(it))
 650             }
 651             PatKind::Wild |
 652             PatKind::Lit(_) |
 653             PatKind::Range(..) |
 654             PatKind::Binding(..) |
 655             PatKind::Path(_) => {
 656                 true
 657             }
 658         }
 659     }
 660
 661     pub fn walk<F>(&self, mut it: F) -> bool
 662         where F: FnMut(&Pat) -> bool
 663     {
 664         self.walk_(&mut it)
 665     }
 666 }
 667
 668 /// A single field in a struct pattern
 669 ///
 670 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
 671 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
 672 /// except is_shorthand is true
 673 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 674 pub struct FieldPat {
 675     /// The identifier for the field
 676     pub name: Name,
 677     /// The pattern the field is destructured to
 678     pub pat: P<Pat>,
 679     pub is_shorthand: bool,
 680 }
 681
 682 /// Explicit binding annotations given in the HIR for a binding. Note
 683 /// that this is not the final binding *mode* that we infer after type
 684 /// inference.
 685 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 686 pub enum BindingAnnotation {
 687   /// No binding annotation given: this means that the final binding mode
 688   /// will depend on whether we have skipped through a `&` reference
 689   /// when matching. For example, the `x` in `Some(x)` will have binding
 690   /// mode `None`; if you do `let Some(x) = &Some(22)`, it will
 691   /// ultimately be inferred to be by-reference.
 692   ///
 693   /// Note that implicit reference skipping is not implemented yet (#42640).
 694   Unannotated,
 695
 696   /// Annotated with `mut x` -- could be either ref or not, similar to `None`.
 697   Mutable,
 698
 699   /// Annotated as `ref`, like `ref x`
 700   Ref,
 701
 702   /// Annotated as `ref mut x`.
 703   RefMut,
 704 }
 705
 706 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 707 pub enum RangeEnd {
 708     Included,
 709     Excluded,
 710 }
 711
 712 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 713 pub enum PatKind {
 714     /// Represents a wildcard pattern (`_`)
 715     Wild,
 716
 717     /// A fresh binding `ref mut binding @ OPT_SUBPATTERN`.
 718     /// The `NodeId` is the canonical ID for the variable being bound,
 719     /// e.g. in `Ok(x) | Err(x)`, both `x` use the same canonical ID,
 720     /// which is the pattern ID of the first `x`.
 721     Binding(BindingAnnotation, NodeId, Spanned<Name>, Option<P<Pat>>),
 722
 723     /// A struct or struct variant pattern, e.g. `Variant {x, y, ..}`.
 724     /// The `bool` is `true` in the presence of a `..`.
 725     Struct(QPath, HirVec<Spanned<FieldPat>>, bool),
 726
 727     /// A tuple struct/variant pattern `Variant(x, y, .., z)`.
 728     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
 729     /// 0 <= position <= subpats.len()
 730     TupleStruct(QPath, HirVec<P<Pat>>, Option<usize>),
 731
 732     /// A path pattern for an unit struct/variant or a (maybe-associated) constant.
 733     Path(QPath),
 734
 735     /// A tuple pattern `(a, b)`.
 736     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
 737     /// 0 <= position <= subpats.len()
 738     Tuple(HirVec<P<Pat>>, Option<usize>),
 739     /// A `box` pattern
 740     Box(P<Pat>),
 741     /// A reference pattern, e.g. `&mut (a, b)`
 742     Ref(P<Pat>, Mutability),
 743     /// A literal
 744     Lit(P<Expr>),
 745     /// A range pattern, e.g. `1...2` or `1..2`
 746     Range(P<Expr>, P<Expr>, RangeEnd),
 747     /// `[a, b, ..i, y, z]` is represented as:
 748     ///     `PatKind::Slice(box [a, b], Some(i), box [y, z])`
 749     Slice(HirVec<P<Pat>>, Option<P<Pat>>, HirVec<P<Pat>>),
 750 }
 751
 752 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 753 pub enum Mutability {
 754     MutMutable,
 755     MutImmutable,
 756 }
 757
 758 impl Mutability {
 759     /// Return MutMutable only if both arguments are mutable.
 760     pub fn and(self, other: Self) -> Self {
 761         match self {
 762             MutMutable => other,
 763             MutImmutable => MutImmutable,
 764         }
 765     }
 766 }
 767
 768 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 769 pub enum BinOp_ {
 770     /// The `+` operator (addition)
 771     BiAdd,
 772     /// The `-` operator (subtraction)
 773     BiSub,
 774     /// The `*` operator (multiplication)
 775     BiMul,
 776     /// The `/` operator (division)
 777     BiDiv,
 778     /// The `%` operator (modulus)
 779     BiRem,
 780     /// The `&&` operator (logical and)
 781     BiAnd,
 782     /// The `||` operator (logical or)
 783     BiOr,
 784     /// The `^` operator (bitwise xor)
 785     BiBitXor,
 786     /// The `&` operator (bitwise and)
 787     BiBitAnd,
 788     /// The `|` operator (bitwise or)
 789     BiBitOr,
 790     /// The `<<` operator (shift left)
 791     BiShl,
 792     /// The `>>` operator (shift right)
 793     BiShr,
 794     /// The `==` operator (equality)
 795     BiEq,
 796     /// The `<` operator (less than)
 797     BiLt,
 798     /// The `<=` operator (less than or equal to)
 799     BiLe,
 800     /// The `!=` operator (not equal to)
 801     BiNe,
 802     /// The `>=` operator (greater than or equal to)
 803     BiGe,
 804     /// The `>` operator (greater than)
 805     BiGt,
 806 }
 807
 808 impl BinOp_ {
 809     pub fn as_str(self) -> &'static str {
 810         match self {
 811             BiAdd => "+",
 812             BiSub => "-",
 813             BiMul => "*",
 814             BiDiv => "/",
 815             BiRem => "%",
 816             BiAnd => "&&",
 817             BiOr => "||",
 818             BiBitXor => "^",
 819             BiBitAnd => "&",
 820             BiBitOr => "|",
 821             BiShl => "<<",
 822             BiShr => ">>",
 823             BiEq => "==",
 824             BiLt => "<",
 825             BiLe => "<=",
 826             BiNe => "!=",
 827             BiGe => ">=",
 828             BiGt => ">",
 829         }
 830     }
 831
 832     pub fn is_lazy(self) -> bool {
 833         match self {
 834             BiAnd | BiOr => true,
 835             _ => false,
 836         }
 837     }
 838
 839     pub fn is_shift(self) -> bool {
 840         match self {
 841             BiShl | BiShr => true,
 842             _ => false,
 843         }
 844     }
 845
 846     pub fn is_comparison(self) -> bool {
 847         match self {
 848             BiEq | BiLt | BiLe | BiNe | BiGt | BiGe => true,
 849             BiAnd |
 850             BiOr |
 851             BiAdd |
 852             BiSub |
 853             BiMul |
 854             BiDiv |
 855             BiRem |
 856             BiBitXor |
 857             BiBitAnd |
 858             BiBitOr |
 859             BiShl |
 860             BiShr => false,
 861         }
 862     }
 863
 864     /// Returns `true` if the binary operator takes its arguments by value
 865     pub fn is_by_value(self) -> bool {
 866         !self.is_comparison()
 867     }
 868 }
 869
 870 pub type BinOp = Spanned<BinOp_>;
 871
 872 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 873 pub enum UnOp {
 874     /// The `*` operator for dereferencing
 875     UnDeref,
 876     /// The `!` operator for logical inversion
 877     UnNot,
 878     /// The `-` operator for negation
 879     UnNeg,
 880 }
 881
 882 impl UnOp {
 883     pub fn as_str(self) -> &'static str {
 884         match self {
 885             UnDeref => "*",
 886             UnNot => "!",
 887             UnNeg => "-",
 888         }
 889     }
 890
 891     /// Returns `true` if the unary operator takes its argument by value
 892     pub fn is_by_value(self) -> bool {
 893         match self {
 894             UnNeg | UnNot => true,
 895             _ => false,
 896         }
 897     }
 898 }
 899
 900 /// A statement
 901 pub type Stmt = Spanned<Stmt_>;
 902
 903 impl fmt::Debug for Stmt_ {
 904     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 905         // Sadness.
 906         let spanned = codemap::dummy_spanned(self.clone());
 907         write!(f,
 908                "stmt({}: {})",
 909                spanned.node.id(),
 910                print::to_string(print::NO_ANN, |s| s.print_stmt(&spanned)))
 911     }
 912 }
 913
 914 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 915 pub enum Stmt_ {
 916     /// Could be an item or a local (let) binding:
 917     StmtDecl(P<Decl>, NodeId),
 918
 919     /// Expr without trailing semi-colon (must have unit type):
 920     StmtExpr(P<Expr>, NodeId),
 921
 922     /// Expr with trailing semi-colon (may have any type):
 923     StmtSemi(P<Expr>, NodeId),
 924 }
 925
 926 impl Stmt_ {
 927     pub fn attrs(&self) -> &[Attribute] {
 928         match *self {
 929             StmtDecl(ref d, _) => d.node.attrs(),
 930             StmtExpr(ref e, _) |
 931             StmtSemi(ref e, _) => &e.attrs,
 932         }
 933     }
 934
 935     pub fn id(&self) -> NodeId {
 936         match *self {
 937             StmtDecl(_, id) => id,
 938             StmtExpr(_, id) => id,
 939             StmtSemi(_, id) => id,
 940         }
 941     }
 942 }
 943
 944 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`
 945 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 946 pub struct Local {
 947     pub pat: P<Pat>,
 948     pub ty: Option<P<Ty>>,
 949     /// Initializer expression to set the value, if any
 950     pub init: Option<P<Expr>>,
 951     pub id: NodeId,
 952     pub hir_id: HirId,
 953     pub span: Span,
 954     pub attrs: ThinVec<Attribute>,
 955     pub source: LocalSource,
 956 }
 957
 958 pub type Decl = Spanned<Decl_>;
 959
 960 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 961 pub enum Decl_ {
 962     /// A local (let) binding:
 963     DeclLocal(P<Local>),
 964     /// An item binding:
 965     DeclItem(ItemId),
 966 }
 967
 968 impl Decl_ {
 969     pub fn attrs(&self) -> &[Attribute] {
 970         match *self {
 971             DeclLocal(ref l) => &l.attrs,
 972             DeclItem(_) => &[]
 973         }
 974     }
 975
 976     pub fn is_local(&self) -> bool {
 977         match *self {
 978             Decl_::DeclLocal(_) => true,
 979             _ => false,
 980         }
 981     }
 982 }
 983
 984 /// represents one arm of a 'match'
 985 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 986 pub struct Arm {
 987     pub attrs: HirVec<Attribute>,
 988     pub pats: HirVec<P<Pat>>,
 989     pub guard: Option<P<Expr>>,
 990     pub body: P<Expr>,
 991 }
 992
 993 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 994 pub struct Field {
 995     pub name: Spanned<Name>,
 996     pub expr: P<Expr>,
 997     pub span: Span,
 998     pub is_shorthand: bool,
 999 }
1000
1001 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1002 pub enum BlockCheckMode {
1003     DefaultBlock,
1004     UnsafeBlock(UnsafeSource),
1005     PushUnsafeBlock(UnsafeSource),
1006     PopUnsafeBlock(UnsafeSource),
1007 }
1008
1009 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1010 pub enum UnsafeSource {
1011     CompilerGenerated,
1012     UserProvided,
1013 }
1014
1015 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug)]
1016 pub struct BodyId {
1017     pub node_id: NodeId,
1018 }
1019
1020 /// The body of a function, closure, or constant value. In the case of
1021 /// a function, the body contains not only the function body itself
1022 /// (which is an expression), but also the argument patterns, since
1023 /// those are something that the caller doesn't really care about.
1024 ///
1025 /// # Examples
1026 ///
1027 /// ```
1028 /// fn foo((x, y): (u32, u32)) -> u32 {
1029 ///     x + y
1030 /// }
1031 /// ```
1032 ///
1033 /// Here, the `Body` associated with `foo()` would contain:
1034 ///
1035 /// - an `arguments` array containing the `(x, y)` pattern
1036 /// - a `value` containing the `x + y` expression (maybe wrapped in a block)
1037 /// - `is_generator` would be false
1038 ///
1039 /// All bodies have an **owner**, which can be accessed via the HIR
1040 /// map using `body_owner_def_id()`.
1041 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1042 pub struct Body {
1043     pub arguments: HirVec<Arg>,
1044     pub value: Expr,
1045     pub is_generator: bool,
1046 }
1047
1048 impl Body {
1049     pub fn id(&self) -> BodyId {
1050         BodyId {
1051             node_id: self.value.id
1052         }
1053     }
1054 }
1055
1056 #[derive(Copy, Clone, Debug)]
1057 pub enum BodyOwnerKind {
1058     /// Functions and methods.
1059     Fn,
1060
1061     /// Constants and associated constants.
1062     Const,
1063
1064     /// Initializer of a `static` item.
1065     Static(Mutability),
1066 }
1067
1068 /// An expression
1069 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
1070 pub struct Expr {
1071     pub id: NodeId,
1072     pub span: Span,
1073     pub node: Expr_,
1074     pub attrs: ThinVec<Attribute>,
1075     pub hir_id: HirId,
1076 }
1077
1078 impl fmt::Debug for Expr {
1079     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1080         write!(f, "expr({}: {})", self.id,
1081                print::to_string(print::NO_ANN, |s| s.print_expr(self)))
1082     }
1083 }
1084
1085 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1086 pub enum Expr_ {
1087     /// A `box x` expression.
1088     ExprBox(P<Expr>),
1089     /// An array (`[a, b, c, d]`)
1090     ExprArray(HirVec<Expr>),
1091     /// A function call
1092     ///
1093     /// The first field resolves to the function itself (usually an `ExprPath`),
1094     /// and the second field is the list of arguments.
1095     /// This also represents calling the constructor of
1096     /// tuple-like ADTs such as tuple structs and enum variants.
1097     ExprCall(P<Expr>, HirVec<Expr>),
1098     /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1099     ///
1100     /// The `PathSegment`/`Span` represent the method name and its generic arguments
1101     /// (within the angle brackets).
1102     /// The first element of the vector of `Expr`s is the expression that evaluates
1103     /// to the object on which the method is being called on (the receiver),
1104     /// and the remaining elements are the rest of the arguments.
1105     /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1106     /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
1107     ExprMethodCall(PathSegment, Span, HirVec<Expr>),
1108     /// A tuple (`(a, b, c ,d)`)
1109     ExprTup(HirVec<Expr>),
1110     /// A binary operation (For example: `a + b`, `a * b`)
1111     ExprBinary(BinOp, P<Expr>, P<Expr>),
1112     /// A unary operation (For example: `!x`, `*x`)
1113     ExprUnary(UnOp, P<Expr>),
1114     /// A literal (For example: `1`, `"foo"`)
1115     ExprLit(P<Lit>),
1116     /// A cast (`foo as f64`)
1117     ExprCast(P<Expr>, P<Ty>),
1118     ExprType(P<Expr>, P<Ty>),
1119     /// An `if` block, with an optional else block
1120     ///
1121     /// `if expr { expr } else { expr }`
1122     ExprIf(P<Expr>, P<Expr>, Option<P<Expr>>),
1123     /// A while loop, with an optional label
1124     ///
1125     /// `'label: while expr { block }`
1126     ExprWhile(P<Expr>, P<Block>, Option<Spanned<Name>>),
1127     /// Conditionless loop (can be exited with break, continue, or return)
1128     ///
1129     /// `'label: loop { block }`
1130     ExprLoop(P<Block>, Option<Spanned<Name>>, LoopSource),
1131     /// A `match` block, with a source that indicates whether or not it is
1132     /// the result of a desugaring, and if so, which kind.
1133     ExprMatch(P<Expr>, HirVec<Arm>, MatchSource),
1134     /// A closure (for example, `move |a, b, c| {a + b + c}`).
1135     ///
1136     /// The final span is the span of the argument block `|...|`
1137     ///
1138     /// This may also be a generator literal, indicated by the final boolean,
1139     /// in that case there is an GeneratorClause.
1140     ExprClosure(CaptureClause, P<FnDecl>, BodyId, Span, bool),
1141     /// A block (`{ ... }`)
1142     ExprBlock(P<Block>),
1143
1144     /// An assignment (`a = foo()`)
1145     ExprAssign(P<Expr>, P<Expr>),
1146     /// An assignment with an operator
1147     ///
1148     /// For example, `a += 1`.
1149     ExprAssignOp(BinOp, P<Expr>, P<Expr>),
1150     /// Access of a named struct field (`obj.foo`)
1151     ExprField(P<Expr>, Spanned<Name>),
1152     /// Access of an unnamed field of a struct or tuple-struct
1153     ///
1154     /// For example, `foo.0`.
1155     ExprTupField(P<Expr>, Spanned<usize>),
1156     /// An indexing operation (`foo[2]`)
1157     ExprIndex(P<Expr>, P<Expr>),
1158
1159     /// Path to a definition, possibly containing lifetime or type parameters.
1160     ExprPath(QPath),
1161
1162     /// A referencing operation (`&a` or `&mut a`)
1163     ExprAddrOf(Mutability, P<Expr>),
1164     /// A `break`, with an optional label to break
1165     ExprBreak(Destination, Option<P<Expr>>),
1166     /// A `continue`, with an optional label
1167     ExprAgain(Destination),
1168     /// A `return`, with an optional value to be returned
1169     ExprRet(Option<P<Expr>>),
1170
1171     /// Inline assembly (from `asm!`), with its outputs and inputs.
1172     ExprInlineAsm(P<InlineAsm>, HirVec<Expr>, HirVec<Expr>),
1173
1174     /// A struct or struct-like variant literal expression.
1175     ///
1176     /// For example, `Foo {x: 1, y: 2}`, or
1177     /// `Foo {x: 1, .. base}`, where `base` is the `Option<Expr>`.
1178     ExprStruct(QPath, HirVec<Field>, Option<P<Expr>>),
1179
1180     /// An array literal constructed from one repeated element.
1181     ///
1182     /// For example, `[1; 5]`. The first expression is the element
1183     /// to be repeated; the second is the number of times to repeat it.
1184     ExprRepeat(P<Expr>, BodyId),
1185
1186     /// A suspension point for generators. This is `yield <expr>` in Rust.
1187     ExprYield(P<Expr>),
1188 }
1189
1190 /// Optionally `Self`-qualified value/type path or associated extension.
1191 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1192 pub enum QPath {
1193     /// Path to a definition, optionally "fully-qualified" with a `Self`
1194     /// type, if the path points to an associated item in a trait.
1195     ///
1196     /// E.g. an unqualified path like `Clone::clone` has `None` for `Self`,
1197     /// while `<Vec<T> as Clone>::clone` has `Some(Vec<T>)` for `Self`,
1198     /// even though they both have the same two-segment `Clone::clone` `Path`.
1199     Resolved(Option<P<Ty>>, P<Path>),
1200
1201     /// Type-related paths, e.g. `<T>::default` or `<T>::Output`.
1202     /// Will be resolved by type-checking to an associated item.
1203     ///
1204     /// UFCS source paths can desugar into this, with `Vec::new` turning into
1205     /// `<Vec>::new`, and `T::X::Y::method` into `<<<T>::X>::Y>::method`,
1206     /// the `X` and `Y` nodes each being a `TyPath(QPath::TypeRelative(..))`.
1207     TypeRelative(P<Ty>, P<PathSegment>)
1208 }
1209
1210 /// Hints at the original code for a let statement
1211 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1212 pub enum LocalSource {
1213     /// A `match _ { .. }`
1214     Normal,
1215     /// A desugared `for _ in _ { .. }` loop
1216     ForLoopDesugar,
1217 }
1218
1219 /// Hints at the original code for a `match _ { .. }`
1220 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1221 pub enum MatchSource {
1222     /// A `match _ { .. }`
1223     Normal,
1224     /// An `if let _ = _ { .. }` (optionally with `else { .. }`)
1225     IfLetDesugar {
1226         contains_else_clause: bool,
1227     },
1228     /// A `while let _ = _ { .. }` (which was desugared to a
1229     /// `loop { match _ { .. } }`)
1230     WhileLetDesugar,
1231     /// A desugared `for _ in _ { .. }` loop
1232     ForLoopDesugar,
1233     /// A desugared `?` operator
1234     TryDesugar,
1235 }
1236
1237 /// The loop type that yielded an ExprLoop
1238 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1239 pub enum LoopSource {
1240     /// A `loop { .. }` loop
1241     Loop,
1242     /// A `while let _ = _ { .. }` loop
1243     WhileLet,
1244     /// A `for _ in _ { .. }` loop
1245     ForLoop,
1246 }
1247
1248 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1249 pub enum LoopIdError {
1250     OutsideLoopScope,
1251     UnlabeledCfInWhileCondition,
1252     UnresolvedLabel,
1253 }
1254
1255 impl fmt::Display for LoopIdError {
1256     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1257         fmt::Display::fmt(match *self {
1258             LoopIdError::OutsideLoopScope => "not inside loop scope",
1259             LoopIdError::UnlabeledCfInWhileCondition =>
1260                 "unlabeled control flow (break or continue) in while condition",
1261             LoopIdError::UnresolvedLabel => "label not found",
1262         }, f)
1263     }
1264 }
1265
1266 // FIXME(cramertj) this should use `Result` once master compiles w/ a vesion of Rust where
1267 // `Result` implements `Encodable`/`Decodable`
1268 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1269 pub enum LoopIdResult {
1270     Ok(NodeId),
1271     Err(LoopIdError),
1272 }
1273 impl Into<Result<NodeId, LoopIdError>> for LoopIdResult {
1274     fn into(self) -> Result<NodeId, LoopIdError> {
1275         match self {
1276             LoopIdResult::Ok(ok) => Ok(ok),
1277             LoopIdResult::Err(err) => Err(err),
1278         }
1279     }
1280 }
1281 impl From<Result<NodeId, LoopIdError>> for LoopIdResult {
1282     fn from(res: Result<NodeId, LoopIdError>) -> Self {
1283         match res {
1284             Ok(ok) => LoopIdResult::Ok(ok),
1285             Err(err) => LoopIdResult::Err(err),
1286         }
1287     }
1288 }
1289
1290 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1291 pub enum ScopeTarget {
1292     Block(NodeId),
1293     Loop(LoopIdResult),
1294 }
1295
1296 impl ScopeTarget {
1297     pub fn opt_id(self) -> Option<NodeId> {
1298         match self {
1299             ScopeTarget::Block(node_id) |
1300             ScopeTarget::Loop(LoopIdResult::Ok(node_id)) => Some(node_id),
1301             ScopeTarget::Loop(LoopIdResult::Err(_)) => None,
1302         }
1303     }
1304 }
1305
1306 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1307 pub struct Destination {
1308     // This is `Some(_)` iff there is an explicit user-specified `label
1309     pub ident: Option<Spanned<Ident>>,
1310
1311     // These errors are caught and then reported during the diagnostics pass in
1312     // librustc_passes/loops.rs
1313     pub target_id: ScopeTarget,
1314 }
1315
1316 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1317 pub enum CaptureClause {
1318     CaptureByValue,
1319     CaptureByRef,
1320 }
1321
1322 // NB: If you change this, you'll probably want to change the corresponding
1323 // type structure in middle/ty.rs as well.
1324 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1325 pub struct MutTy {
1326     pub ty: P<Ty>,
1327     pub mutbl: Mutability,
1328 }
1329
1330 /// Represents a method's signature in a trait declaration or implementation.
1331 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1332 pub struct MethodSig {
1333     pub unsafety: Unsafety,
1334     pub constness: Constness,
1335     pub abi: Abi,
1336     pub decl: P<FnDecl>,
1337 }
1338
1339 // The bodies for items are stored "out of line", in a separate
1340 // hashmap in the `Crate`. Here we just record the node-id of the item
1341 // so it can fetched later.
1342 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug)]
1343 pub struct TraitItemId {
1344     pub node_id: NodeId,
1345 }
1346
1347 /// Represents an item declaration within a trait declaration,
1348 /// possibly including a default implementation. A trait item is
1349 /// either required (meaning it doesn't have an implementation, just a
1350 /// signature) or provided (meaning it has a default implementation).
1351 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1352 pub struct TraitItem {
1353     pub id: NodeId,
1354     pub name: Name,
1355     pub hir_id: HirId,
1356     pub attrs: HirVec<Attribute>,
1357     pub generics: Generics,
1358     pub node: TraitItemKind,
1359     pub span: Span,
1360 }
1361
1362 /// A trait method's body (or just argument names).
1363 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1364 pub enum TraitMethod {
1365     /// No default body in the trait, just a signature.
1366     Required(HirVec<Spanned<Name>>),
1367
1368     /// Both signature and body are provided in the trait.
1369     Provided(BodyId),
1370 }
1371
1372 /// Represents a trait method or associated constant or type
1373 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1374 pub enum TraitItemKind {
1375     /// An associated constant with an optional value (otherwise `impl`s
1376     /// must contain a value)
1377     Const(P<Ty>, Option<BodyId>),
1378     /// A method with an optional body
1379     Method(MethodSig, TraitMethod),
1380     /// An associated type with (possibly empty) bounds and optional concrete
1381     /// type
1382     Type(TyParamBounds, Option<P<Ty>>),
1383 }
1384
1385 // The bodies for items are stored "out of line", in a separate
1386 // hashmap in the `Crate`. Here we just record the node-id of the item
1387 // so it can fetched later.
1388 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug)]
1389 pub struct ImplItemId {
1390     pub node_id: NodeId,
1391 }
1392
1393 /// Represents anything within an `impl` block
1394 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1395 pub struct ImplItem {
1396     pub id: NodeId,
1397     pub name: Name,
1398     pub hir_id: HirId,
1399     pub vis: Visibility,
1400     pub defaultness: Defaultness,
1401     pub attrs: HirVec<Attribute>,
1402     pub generics: Generics,
1403     pub node: ImplItemKind,
1404     pub span: Span,
1405 }
1406
1407 /// Represents different contents within `impl`s
1408 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1409 pub enum ImplItemKind {
1410     /// An associated constant of the given type, set to the constant result
1411     /// of the expression
1412     Const(P<Ty>, BodyId),
1413     /// A method implementation with the given signature and body
1414     Method(MethodSig, BodyId),
1415     /// An associated type
1416     Type(P<Ty>),
1417 }
1418
1419 // Bind a type to an associated type: `A=Foo`.
1420 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1421 pub struct TypeBinding {
1422     pub id: NodeId,
1423     pub name: Name,
1424     pub ty: P<Ty>,
1425     pub span: Span,
1426 }
1427
1428
1429 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
1430 pub struct Ty {
1431     pub id: NodeId,
1432     pub node: Ty_,
1433     pub span: Span,
1434     pub hir_id: HirId,
1435 }
1436
1437 impl fmt::Debug for Ty {
1438     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1439         write!(f, "type({})",
1440                print::to_string(print::NO_ANN, |s| s.print_type(self)))
1441     }
1442 }
1443
1444 /// Not represented directly in the AST, referred to by name through a ty_path.
1445 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1446 pub enum PrimTy {
1447     TyInt(IntTy),
1448     TyUint(UintTy),
1449     TyFloat(FloatTy),
1450     TyStr,
1451     TyBool,
1452     TyChar,
1453 }
1454
1455 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1456 pub struct BareFnTy {
1457     pub unsafety: Unsafety,
1458     pub abi: Abi,
1459     pub lifetimes: HirVec<LifetimeDef>,
1460     pub decl: P<FnDecl>,
1461     pub arg_names: HirVec<Spanned<Name>>,
1462 }
1463
1464 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1465 /// The different kinds of types recognized by the compiler
1466 pub enum Ty_ {
1467     /// A variable length slice (`[T]`)
1468     TySlice(P<Ty>),
1469     /// A fixed length array (`[T; n]`)
1470     TyArray(P<Ty>, BodyId),
1471     /// A raw pointer (`*const T` or `*mut T`)
1472     TyPtr(MutTy),
1473     /// A reference (`&'a T` or `&'a mut T`)
1474     TyRptr(Lifetime, MutTy),
1475     /// A bare function (e.g. `fn(usize) -> bool`)
1476     TyBareFn(P<BareFnTy>),
1477     /// The never type (`!`)
1478     TyNever,
1479     /// A tuple (`(A, B, C, D,...)`)
1480     TyTup(HirVec<P<Ty>>),
1481     /// A path to a type definition (`module::module::...::Type`), or an
1482     /// associated type, e.g. `<Vec<T> as Trait>::Type` or `<T>::Target`.
1483     ///
1484     /// Type parameters may be stored in each `PathSegment`.
1485     TyPath(QPath),
1486     /// A trait object type `Bound1 + Bound2 + Bound3`
1487     /// where `Bound` is a trait or a lifetime.
1488     TyTraitObject(HirVec<PolyTraitRef>, Lifetime),
1489     /// An exsitentially quantified (there exists a type satisfying) `impl
1490     /// Bound1 + Bound2 + Bound3` type where `Bound` is a trait or a lifetime.
1491     TyImplTraitExistential(TyParamBounds),
1492     /// An universally quantified (for all types satisfying) `impl
1493     /// Bound1 + Bound2 + Bound3` type where `Bound` is a trait or a lifetime.
1494     TyImplTraitUniversal(DefId, TyParamBounds),
1495     /// Unused for now
1496     TyTypeof(BodyId),
1497     /// TyInfer means the type should be inferred instead of it having been
1498     /// specified. This can appear anywhere in a type.
1499     TyInfer,
1500     /// Placeholder for a type that has failed to be defined.
1501     TyErr,
1502 }
1503
1504 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1505 pub struct InlineAsmOutput {
1506     pub constraint: Symbol,
1507     pub is_rw: bool,
1508     pub is_indirect: bool,
1509 }
1510
1511 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1512 pub struct InlineAsm {
1513     pub asm: Symbol,
1514     pub asm_str_style: StrStyle,
1515     pub outputs: HirVec<InlineAsmOutput>,
1516     pub inputs: HirVec<Symbol>,
1517     pub clobbers: HirVec<Symbol>,
1518     pub volatile: bool,
1519     pub alignstack: bool,
1520     pub dialect: AsmDialect,
1521     pub ctxt: SyntaxContext,
1522 }
1523
1524 /// represents an argument in a function header
1525 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1526 pub struct Arg {
1527     pub pat: P<Pat>,
1528     pub id: NodeId,
1529     pub hir_id: HirId,
1530 }
1531
1532 /// Represents the header (not the body) of a function declaration
1533 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1534 pub struct FnDecl {
1535     pub inputs: HirVec<P<Ty>>,
1536     pub output: FunctionRetTy,
1537     pub variadic: bool,
1538     /// True if this function has an `self`, `&self` or `&mut self` receiver
1539     /// (but not a `self: Xxx` one).
1540     pub has_implicit_self: bool,
1541 }
1542
1543 /// Is the trait definition an auto trait?
1544 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1545 pub enum IsAuto {
1546     Yes,
1547     No
1548 }
1549
1550 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1551 pub enum Unsafety {
1552     Unsafe,
1553     Normal,
1554 }
1555
1556 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1557 pub enum Constness {
1558     Const,
1559     NotConst,
1560 }
1561
1562 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1563 pub enum Defaultness {
1564     Default { has_value: bool },
1565     Final,
1566 }
1567
1568 impl Defaultness {
1569     pub fn has_value(&self) -> bool {
1570         match *self {
1571             Defaultness::Default { has_value, .. } => has_value,
1572             Defaultness::Final => true,
1573         }
1574     }
1575
1576     pub fn is_final(&self) -> bool {
1577         *self == Defaultness::Final
1578     }
1579
1580     pub fn is_default(&self) -> bool {
1581         match *self {
1582             Defaultness::Default { .. } => true,
1583             _ => false,
1584         }
1585     }
1586 }
1587
1588 impl fmt::Display for Unsafety {
1589     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1590         fmt::Display::fmt(match *self {
1591                               Unsafety::Normal => "normal",
1592                               Unsafety::Unsafe => "unsafe",
1593                           },
1594                           f)
1595     }
1596 }
1597
1598 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
1599 pub enum ImplPolarity {
1600     /// `impl Trait for Type`
1601     Positive,
1602     /// `impl !Trait for Type`
1603     Negative,
1604 }
1605
1606 impl fmt::Debug for ImplPolarity {
1607     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1608         match *self {
1609             ImplPolarity::Positive => "positive".fmt(f),
1610             ImplPolarity::Negative => "negative".fmt(f),
1611         }
1612     }
1613 }
1614
1615
1616 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1617 pub enum FunctionRetTy {
1618     /// Return type is not specified.
1619     ///
1620     /// Functions default to `()` and
1621     /// closures default to inference. Span points to where return
1622     /// type would be inserted.
1623     DefaultReturn(Span),
1624     /// Everything else
1625     Return(P<Ty>),
1626 }
1627
1628 impl FunctionRetTy {
1629     pub fn span(&self) -> Span {
1630         match *self {
1631             DefaultReturn(span) => span,
1632             Return(ref ty) => ty.span,
1633         }
1634     }
1635 }
1636
1637 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1638 pub struct Mod {
1639     /// A span from the first token past `{` to the last token until `}`.
1640     /// For `mod foo;`, the inner span ranges from the first token
1641     /// to the last token in the external file.
1642     pub inner: Span,
1643     pub item_ids: HirVec<ItemId>,
1644 }
1645
1646 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1647 pub struct ForeignMod {
1648     pub abi: Abi,
1649     pub items: HirVec<ForeignItem>,
1650 }
1651
1652 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1653 pub struct GlobalAsm {
1654     pub asm: Symbol,
1655     pub ctxt: SyntaxContext,
1656 }
1657
1658 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1659 pub struct EnumDef {
1660     pub variants: HirVec<Variant>,
1661 }
1662
1663 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1664 pub struct Variant_ {
1665     pub name: Name,
1666     pub attrs: HirVec<Attribute>,
1667     pub data: VariantData,
1668     /// Explicit discriminant, eg `Foo = 1`
1669     pub disr_expr: Option<BodyId>,
1670 }
1671
1672 pub type Variant = Spanned<Variant_>;
1673
1674 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1675 pub enum UseKind {
1676     /// One import, e.g. `use foo::bar` or `use foo::bar as baz`.
1677     /// Also produced for each element of a list `use`, e.g.
1678     // `use foo::{a, b}` lowers to `use foo::a; use foo::b;`.
1679     Single,
1680
1681     /// Glob import, e.g. `use foo::*`.
1682     Glob,
1683
1684     /// Degenerate list import, e.g. `use foo::{a, b}` produces
1685     /// an additional `use foo::{}` for performing checks such as
1686     /// unstable feature gating. May be removed in the future.
1687     ListStem,
1688 }
1689
1690 /// TraitRef's appear in impls.
1691 ///
1692 /// resolve maps each TraitRef's ref_id to its defining trait; that's all
1693 /// that the ref_id is for. Note that ref_id's value is not the NodeId of the
1694 /// trait being referred to but just a unique NodeId that serves as a key
1695 /// within the DefMap.
1696 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1697 pub struct TraitRef {
1698     pub path: Path,
1699     pub ref_id: NodeId,
1700 }
1701
1702 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1703 pub struct PolyTraitRef {
1704     /// The `'a` in `<'a> Foo<&'a T>`
1705     pub bound_lifetimes: HirVec<LifetimeDef>,
1706
1707     /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`
1708     pub trait_ref: TraitRef,
1709
1710     pub span: Span,
1711 }
1712
1713 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1714 pub enum Visibility {
1715     Public,
1716     Crate,
1717     Restricted { path: P<Path>, id: NodeId },
1718     Inherited,
1719 }
1720
1721 impl Visibility {
1722     pub fn is_pub_restricted(&self) -> bool {
1723         use self::Visibility::*;
1724         match self {
1725             &Public |
1726             &Inherited => false,
1727             &Crate |
1728             &Restricted { .. } => true,
1729         }
1730     }
1731 }
1732
1733 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1734 pub struct StructField {
1735     pub span: Span,
1736     pub name: Name,
1737     pub vis: Visibility,
1738     pub id: NodeId,
1739     pub ty: P<Ty>,
1740     pub attrs: HirVec<Attribute>,
1741 }
1742
1743 impl StructField {
1744     // Still necessary in couple of places
1745     pub fn is_positional(&self) -> bool {
1746         let first = self.name.as_str().as_bytes()[0];
1747         first >= b'0' && first <= b'9'
1748     }
1749 }
1750
1751 /// Fields and Ids of enum variants and structs
1752 ///
1753 /// For enum variants: `NodeId` represents both an Id of the variant itself (relevant for all
1754 /// variant kinds) and an Id of the variant's constructor (not relevant for `Struct`-variants).
1755 /// One shared Id can be successfully used for these two purposes.
1756 /// Id of the whole enum lives in `Item`.
1757 ///
1758 /// For structs: `NodeId` represents an Id of the structure's constructor, so it is not actually
1759 /// used for `Struct`-structs (but still presents). Structures don't have an analogue of "Id of
1760 /// the variant itself" from enum variants.
1761 /// Id of the whole struct lives in `Item`.
1762 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1763 pub enum VariantData {
1764     Struct(HirVec<StructField>, NodeId),
1765     Tuple(HirVec<StructField>, NodeId),
1766     Unit(NodeId),
1767 }
1768
1769 impl VariantData {
1770     pub fn fields(&self) -> &[StructField] {
1771         match *self {
1772             VariantData::Struct(ref fields, _) | VariantData::Tuple(ref fields, _) => fields,
1773             _ => &[],
1774         }
1775     }
1776     pub fn id(&self) -> NodeId {
1777         match *self {
1778             VariantData::Struct(_, id) | VariantData::Tuple(_, id) | VariantData::Unit(id) => id,
1779         }
1780     }
1781     pub fn is_struct(&self) -> bool {
1782         if let VariantData::Struct(..) = *self {
1783             true
1784         } else {
1785             false
1786         }
1787     }
1788     pub fn is_tuple(&self) -> bool {
1789         if let VariantData::Tuple(..) = *self {
1790             true
1791         } else {
1792             false
1793         }
1794     }
1795     pub fn is_unit(&self) -> bool {
1796         if let VariantData::Unit(..) = *self {
1797             true
1798         } else {
1799             false
1800         }
1801     }
1802 }
1803
1804 // The bodies for items are stored "out of line", in a separate
1805 // hashmap in the `Crate`. Here we just record the node-id of the item
1806 // so it can fetched later.
1807 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1808 pub struct ItemId {
1809     pub id: NodeId,
1810 }
1811
1812 /// An item
1813 ///
1814 /// The name might be a dummy name in case of anonymous items
1815 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1816 pub struct Item {
1817     pub name: Name,
1818     pub id: NodeId,
1819     pub hir_id: HirId,
1820     pub attrs: HirVec<Attribute>,
1821     pub node: Item_,
1822     pub vis: Visibility,
1823     pub span: Span,
1824 }
1825
1826 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1827 pub enum Item_ {
1828     /// An `extern crate` item, with optional original crate name,
1829     ///
1830     /// e.g. `extern crate foo` or `extern crate foo_bar as foo`
1831     ItemExternCrate(Option<Name>),
1832
1833     /// `use foo::bar::*;` or `use foo::bar::baz as quux;`
1834     ///
1835     /// or just
1836     ///
1837     /// `use foo::bar::baz;` (with `as baz` implicitly on the right)
1838     ItemUse(P<Path>, UseKind),
1839
1840     /// A `static` item
1841     ItemStatic(P<Ty>, Mutability, BodyId),
1842     /// A `const` item
1843     ItemConst(P<Ty>, BodyId),
1844     /// A function declaration
1845     ItemFn(P<FnDecl>, Unsafety, Constness, Abi, Generics, BodyId),
1846     /// A module
1847     ItemMod(Mod),
1848     /// An external module
1849     ItemForeignMod(ForeignMod),
1850     /// Module-level inline assembly (from global_asm!)
1851     ItemGlobalAsm(P<GlobalAsm>),
1852     /// A type alias, e.g. `type Foo = Bar<u8>`
1853     ItemTy(P<Ty>, Generics),
1854     /// An enum definition, e.g. `enum Foo<A, B> {C<A>, D<B>}`
1855     ItemEnum(EnumDef, Generics),
1856     /// A struct definition, e.g. `struct Foo<A> {x: A}`
1857     ItemStruct(VariantData, Generics),
1858     /// A union definition, e.g. `union Foo<A, B> {x: A, y: B}`
1859     ItemUnion(VariantData, Generics),
1860     /// Represents a Trait Declaration
1861     ItemTrait(IsAuto, Unsafety, Generics, TyParamBounds, HirVec<TraitItemRef>),
1862
1863     /// Auto trait implementations
1864     ///
1865     /// `impl Trait for .. {}`
1866     ItemAutoImpl(Unsafety, TraitRef),
1867     /// An implementation, eg `impl<A> Trait for Foo { .. }`
1868     ItemImpl(Unsafety,
1869              ImplPolarity,
1870              Defaultness,
1871              Generics,
1872              Option<TraitRef>, // (optional) trait this impl implements
1873              P<Ty>, // self
1874              HirVec<ImplItemRef>),
1875 }
1876
1877 impl Item_ {
1878     pub fn descriptive_variant(&self) -> &str {
1879         match *self {
1880             ItemExternCrate(..) => "extern crate",
1881             ItemUse(..) => "use",
1882             ItemStatic(..) => "static item",
1883             ItemConst(..) => "constant item",
1884             ItemFn(..) => "function",
1885             ItemMod(..) => "module",
1886             ItemForeignMod(..) => "foreign module",
1887             ItemGlobalAsm(..) => "global asm",
1888             ItemTy(..) => "type alias",
1889             ItemEnum(..) => "enum",
1890             ItemStruct(..) => "struct",
1891             ItemUnion(..) => "union",
1892             ItemTrait(..) => "trait",
1893             ItemImpl(..) |
1894             ItemAutoImpl(..) => "item",
1895         }
1896     }
1897
1898     pub fn adt_kind(&self) -> Option<AdtKind> {
1899         match *self {
1900             ItemStruct(..) => Some(AdtKind::Struct),
1901             ItemUnion(..) => Some(AdtKind::Union),
1902             ItemEnum(..) => Some(AdtKind::Enum),
1903             _ => None,
1904         }
1905     }
1906
1907     pub fn generics(&self) -> Option<&Generics> {
1908         Some(match *self {
1909             ItemFn(_, _, _, _, ref generics, _) |
1910             ItemTy(_, ref generics) |
1911             ItemEnum(_, ref generics) |
1912             ItemStruct(_, ref generics) |
1913             ItemUnion(_, ref generics) |
1914             ItemTrait(_, _, ref generics, _, _) |
1915             ItemImpl(_, _, _, ref generics, _, _, _)=> generics,
1916             _ => return None
1917         })
1918     }
1919 }
1920
1921 /// A reference from an trait to one of its associated items. This
1922 /// contains the item's id, naturally, but also the item's name and
1923 /// some other high-level details (like whether it is an associated
1924 /// type or method, and whether it is public). This allows other
1925 /// passes to find the impl they want without loading the id (which
1926 /// means fewer edges in the incremental compilation graph).
1927 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1928 pub struct TraitItemRef {
1929     pub id: TraitItemId,
1930     pub name: Name,
1931     pub kind: AssociatedItemKind,
1932     pub span: Span,
1933     pub defaultness: Defaultness,
1934 }
1935
1936 /// A reference from an impl to one of its associated items. This
1937 /// contains the item's id, naturally, but also the item's name and
1938 /// some other high-level details (like whether it is an associated
1939 /// type or method, and whether it is public). This allows other
1940 /// passes to find the impl they want without loading the id (which
1941 /// means fewer edges in the incremental compilation graph).
1942 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1943 pub struct ImplItemRef {
1944     pub id: ImplItemId,
1945     pub name: Name,
1946     pub kind: AssociatedItemKind,
1947     pub span: Span,
1948     pub vis: Visibility,
1949     pub defaultness: Defaultness,
1950 }
1951
1952 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1953 pub enum AssociatedItemKind {
1954     Const,
1955     Method { has_self: bool },
1956     Type,
1957 }
1958
1959 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1960 pub struct ForeignItem {
1961     pub name: Name,
1962     pub attrs: HirVec<Attribute>,
1963     pub node: ForeignItem_,
1964     pub id: NodeId,
1965     pub span: Span,
1966     pub vis: Visibility,
1967 }
1968
1969 /// An item within an `extern` block
1970 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1971 pub enum ForeignItem_ {
1972     /// A foreign function
1973     ForeignItemFn(P<FnDecl>, HirVec<Spanned<Name>>, Generics),
1974     /// A foreign static item (`static ext: u8`), with optional mutability
1975     /// (the boolean is true when mutable)
1976     ForeignItemStatic(P<Ty>, bool),
1977     /// A foreign type
1978     ForeignItemType,
1979 }
1980
1981 impl ForeignItem_ {
1982     pub fn descriptive_variant(&self) -> &str {
1983         match *self {
1984             ForeignItemFn(..) => "foreign function",
1985             ForeignItemStatic(..) => "foreign static item",
1986             ForeignItemType => "foreign type",
1987         }
1988     }
1989 }
1990
1991 /// A free variable referred to in a function.
1992 #[derive(Debug, Copy, Clone, RustcEncodable, RustcDecodable)]
1993 pub struct Freevar {
1994     /// The variable being accessed free.
1995     pub def: Def,
1996
1997     // First span where it is accessed (there can be multiple).
1998     pub span: Span
1999 }
2000
2001 impl Freevar {
2002     pub fn var_id(&self) -> NodeId {
2003         match self.def {
2004             Def::Local(id) | Def::Upvar(id, ..) => id,
2005             _ => bug!("Freevar::var_id: bad def ({:?})", self.def)
2006         }
2007     }
2008 }
2009
2010 pub type FreevarMap = NodeMap<Vec<Freevar>>;
2011
2012 pub type CaptureModeMap = NodeMap<CaptureClause>;
2013
2014 #[derive(Clone, Debug)]
2015 pub struct TraitCandidate {
2016     pub def_id: DefId,
2017     pub import_id: Option<NodeId>,
2018 }
2019
2020 // Trait method resolution
2021 pub type TraitMap = NodeMap<Vec<TraitCandidate>>;
2022
2023 // Map from the NodeId of a glob import to a list of items which are actually
2024 // imported.
2025 pub type GlobMap = NodeMap<FxHashSet<Name>>;