src/librustc_front/hir.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::ExplicitSelf_::*;
  19 pub use self::Expr_::*;
  20 pub use self::FunctionRetTy::*;
  21 pub use self::ForeignItem_::*;
  22 pub use self::Item_::*;
  23 pub use self::Mutability::*;
  24 pub use self::PathListItem_::*;
  25 pub use self::PrimTy::*;
  26 pub use self::Stmt_::*;
  27 pub use self::StructFieldKind::*;
  28 pub use self::TraitItem_::*;
  29 pub use self::Ty_::*;
  30 pub use self::TyParamBound::*;
  31 pub use self::UnOp::*;
  32 pub use self::UnsafeSource::*;
  33 pub use self::ViewPath_::*;
  34 pub use self::Visibility::*;
  35 pub use self::PathParameters::*;
  36
  37 use intravisit::Visitor;
  38 use std::collections::BTreeMap;
  39 use syntax::codemap::{self, Span, Spanned, DUMMY_SP, ExpnId};
  40 use syntax::abi::Abi;
  41 use syntax::ast::{Name, NodeId, DUMMY_NODE_ID, TokenTree, AsmDialect};
  42 use syntax::ast::{Attribute, Lit, StrStyle, FloatTy, IntTy, UintTy, MetaItem};
  43 use syntax::attr::ThinAttributes;
  44 use syntax::parse::token::InternedString;
  45 use syntax::ptr::P;
  46
  47 use print::pprust;
  48 use util;
  49
  50 use std::fmt;
  51 use std::hash::{Hash, Hasher};
  52 use serialize::{Encodable, Decodable, Encoder, Decoder};
  53
  54 /// HIR doesn't commit to a concrete storage type and have its own alias for a vector.
  55 /// It can be `Vec`, `P<[T]>` or potentially `Box<[T]>`, or some other container with similar
  56 /// behavior. Unlike AST, HIR is mostly a static structure, so we can use an owned slice instead
  57 /// of `Vec` to avoid keeping extra capacity.
  58 pub type HirVec<T> = P<[T]>;
  59
  60 macro_rules! hir_vec {
  61     ($elem:expr; $n:expr) => (
  62         $crate::hir::HirVec::from(vec![$elem; $n])
  63     );
  64     ($($x:expr),*) => (
  65         $crate::hir::HirVec::from(vec![$($x),*])
  66     );
  67     ($($x:expr,)*) => (vec![$($x),*])
  68 }
  69
  70 /// Identifier in HIR
  71 #[derive(Clone, Copy, Eq)]
  72 pub struct Ident {
  73     /// Hygienic name (renamed), should be used by default
  74     pub name: Name,
  75     /// Unhygienic name (original, not renamed), needed in few places in name resolution
  76     pub unhygienic_name: Name,
  77 }
  78
  79 impl Ident {
  80     /// Creates a HIR identifier with both `name` and `unhygienic_name` initialized with
  81     /// the argument. Hygiene properties of the created identifier depend entirely on this
  82     /// argument. If the argument is a plain interned string `intern("iter")`, then the result
  83     /// is unhygienic and can interfere with other entities named "iter". If the argument is
  84     /// a "fresh" name created with `gensym("iter")`, then the result is hygienic and can't
  85     /// interfere with other entities having the same string as a name.
  86     pub fn from_name(name: Name) -> Ident {
  87         Ident { name: name, unhygienic_name: name }
  88     }
  89 }
  90
  91 impl PartialEq for Ident {
  92     fn eq(&self, other: &Ident) -> bool {
  93         self.name == other.name
  94     }
  95 }
  96
  97 impl Hash for Ident {
  98     fn hash<H: Hasher>(&self, state: &mut H) {
  99         self.name.hash(state)
 100     }
 101 }
 102
 103 impl fmt::Debug for Ident {
 104     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 105         fmt::Debug::fmt(&self.name, f)
 106     }
 107 }
 108
 109 impl fmt::Display for Ident {
 110     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 111         fmt::Display::fmt(&self.name, f)
 112     }
 113 }
 114
 115 impl Encodable for Ident {
 116     fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
 117         self.name.encode(s)
 118     }
 119 }
 120
 121 impl Decodable for Ident {
 122     fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
 123         Ok(Ident::from_name(try!(Name::decode(d))))
 124     }
 125 }
 126
 127 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
 128 pub struct Lifetime {
 129     pub id: NodeId,
 130     pub span: Span,
 131     pub name: Name,
 132 }
 133
 134 impl fmt::Debug for Lifetime {
 135     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 136         write!(f,
 137                "lifetime({}: {})",
 138                self.id,
 139                pprust::lifetime_to_string(self))
 140     }
 141 }
 142
 143 /// A lifetime definition, eg `'a: 'b+'c+'d`
 144 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 145 pub struct LifetimeDef {
 146     pub lifetime: Lifetime,
 147     pub bounds: HirVec<Lifetime>,
 148 }
 149
 150 /// A "Path" is essentially Rust's notion of a name; for instance:
 151 /// std::cmp::PartialEq  .  It's represented as a sequence of identifiers,
 152 /// along with a bunch of supporting information.
 153 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 154 pub struct Path {
 155     pub span: Span,
 156     /// A `::foo` path, is relative to the crate root rather than current
 157     /// module (like paths in an import).
 158     pub global: bool,
 159     /// The segments in the path: the things separated by `::`.
 160     pub segments: HirVec<PathSegment>,
 161 }
 162
 163 impl fmt::Debug for Path {
 164     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 165         write!(f, "path({})", pprust::path_to_string(self))
 166     }
 167 }
 168
 169 impl fmt::Display for Path {
 170     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 171         write!(f, "{}", pprust::path_to_string(self))
 172     }
 173 }
 174
 175 /// A segment of a path: an identifier, an optional lifetime, and a set of
 176 /// types.
 177 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 178 pub struct PathSegment {
 179     /// The identifier portion of this path segment.
 180     ///
 181     /// Hygiene properties of this identifier are worth noting.
 182     /// Most path segments are not hygienic and they are not renamed during
 183     /// lowering from AST to HIR (see comments to `fn lower_path`). However segments from
 184     /// unqualified paths with one segment originating from `ExprPath` (local-variable-like paths)
 185     /// can be hygienic, so they are renamed. You should not normally care about this peculiarity
 186     /// and just use `identifier.name` unless you modify identifier resolution code
 187     /// (`fn resolve_identifier` and other functions called by it in `rustc_resolve`).
 188     pub identifier: Ident,
 189
 190     /// Type/lifetime parameters attached to this path. They come in
 191     /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`. Note that
 192     /// this is more than just simple syntactic sugar; the use of
 193     /// parens affects the region binding rules, so we preserve the
 194     /// distinction.
 195     pub parameters: PathParameters,
 196 }
 197
 198 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 199 pub enum PathParameters {
 200     /// The `<'a, A,B,C>` in `foo::bar::baz::<'a, A,B,C>`
 201     AngleBracketedParameters(AngleBracketedParameterData),
 202     /// The `(A,B)` and `C` in `Foo(A,B) -> C`
 203     ParenthesizedParameters(ParenthesizedParameterData),
 204 }
 205
 206 impl PathParameters {
 207     pub fn none() -> PathParameters {
 208         AngleBracketedParameters(AngleBracketedParameterData {
 209             lifetimes: HirVec::new(),
 210             types: HirVec::new(),
 211             bindings: HirVec::new(),
 212         })
 213     }
 214
 215     pub fn is_empty(&self) -> bool {
 216         match *self {
 217             AngleBracketedParameters(ref data) => data.is_empty(),
 218
 219             // Even if the user supplied no types, something like
 220             // `X()` is equivalent to `X<(),()>`.
 221             ParenthesizedParameters(..) => false,
 222         }
 223     }
 224
 225     pub fn has_lifetimes(&self) -> bool {
 226         match *self {
 227             AngleBracketedParameters(ref data) => !data.lifetimes.is_empty(),
 228             ParenthesizedParameters(_) => false,
 229         }
 230     }
 231
 232     pub fn has_types(&self) -> bool {
 233         match *self {
 234             AngleBracketedParameters(ref data) => !data.types.is_empty(),
 235             ParenthesizedParameters(..) => true,
 236         }
 237     }
 238
 239     /// Returns the types that the user wrote. Note that these do not necessarily map to the type
 240     /// parameters in the parenthesized case.
 241     pub fn types(&self) -> HirVec<&P<Ty>> {
 242         match *self {
 243             AngleBracketedParameters(ref data) => {
 244                 data.types.iter().collect()
 245             }
 246             ParenthesizedParameters(ref data) => {
 247                 data.inputs
 248                     .iter()
 249                     .chain(data.output.iter())
 250                     .collect()
 251             }
 252         }
 253     }
 254
 255     pub fn lifetimes(&self) -> HirVec<&Lifetime> {
 256         match *self {
 257             AngleBracketedParameters(ref data) => {
 258                 data.lifetimes.iter().collect()
 259             }
 260             ParenthesizedParameters(_) => {
 261                 HirVec::new()
 262             }
 263         }
 264     }
 265
 266     pub fn bindings(&self) -> HirVec<&TypeBinding> {
 267         match *self {
 268             AngleBracketedParameters(ref data) => {
 269                 data.bindings.iter().collect()
 270             }
 271             ParenthesizedParameters(_) => {
 272                 HirVec::new()
 273             }
 274         }
 275     }
 276 }
 277
 278 /// A path like `Foo<'a, T>`
 279 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 280 pub struct AngleBracketedParameterData {
 281     /// The lifetime parameters for this path segment.
 282     pub lifetimes: HirVec<Lifetime>,
 283     /// The type parameters for this path segment, if present.
 284     pub types: HirVec<P<Ty>>,
 285     /// Bindings (equality constraints) on associated types, if present.
 286     /// E.g., `Foo<A=Bar>`.
 287     pub bindings: HirVec<TypeBinding>,
 288 }
 289
 290 impl AngleBracketedParameterData {
 291     fn is_empty(&self) -> bool {
 292         self.lifetimes.is_empty() && self.types.is_empty() && self.bindings.is_empty()
 293     }
 294 }
 295
 296 /// A path like `Foo(A,B) -> C`
 297 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 298 pub struct ParenthesizedParameterData {
 299     /// Overall span
 300     pub span: Span,
 301
 302     /// `(A,B)`
 303     pub inputs: HirVec<P<Ty>>,
 304
 305     /// `C`
 306     pub output: Option<P<Ty>>,
 307 }
 308
 309 /// The AST represents all type param bounds as types.
 310 /// typeck::collect::compute_bounds matches these against
 311 /// the "special" built-in traits (see middle::lang_items) and
 312 /// detects Copy, Send and Sync.
 313 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 314 pub enum TyParamBound {
 315     TraitTyParamBound(PolyTraitRef, TraitBoundModifier),
 316     RegionTyParamBound(Lifetime),
 317 }
 318
 319 /// A modifier on a bound, currently this is only used for `?Sized`, where the
 320 /// modifier is `Maybe`. Negative bounds should also be handled here.
 321 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 322 pub enum TraitBoundModifier {
 323     None,
 324     Maybe,
 325 }
 326
 327 pub type TyParamBounds = HirVec<TyParamBound>;
 328
 329 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 330 pub struct TyParam {
 331     pub name: Name,
 332     pub id: NodeId,
 333     pub bounds: TyParamBounds,
 334     pub default: Option<P<Ty>>,
 335     pub span: Span,
 336 }
 337
 338 /// Represents lifetimes and type parameters attached to a declaration
 339 /// of a function, enum, trait, etc.
 340 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 341 pub struct Generics {
 342     pub lifetimes: HirVec<LifetimeDef>,
 343     pub ty_params: HirVec<TyParam>,
 344     pub where_clause: WhereClause,
 345 }
 346
 347 impl Generics {
 348     pub fn is_lt_parameterized(&self) -> bool {
 349         !self.lifetimes.is_empty()
 350     }
 351     pub fn is_type_parameterized(&self) -> bool {
 352         !self.ty_params.is_empty()
 353     }
 354     pub fn is_parameterized(&self) -> bool {
 355         self.is_lt_parameterized() || self.is_type_parameterized()
 356     }
 357 }
 358
 359 /// A `where` clause in a definition
 360 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 361 pub struct WhereClause {
 362     pub id: NodeId,
 363     pub predicates: HirVec<WherePredicate>,
 364 }
 365
 366 /// A single predicate in a `where` clause
 367 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 368 pub enum WherePredicate {
 369     /// A type binding, eg `for<'c> Foo: Send+Clone+'c`
 370     BoundPredicate(WhereBoundPredicate),
 371     /// A lifetime predicate, e.g. `'a: 'b+'c`
 372     RegionPredicate(WhereRegionPredicate),
 373     /// An equality predicate (unsupported)
 374     EqPredicate(WhereEqPredicate),
 375 }
 376
 377 /// A type bound, eg `for<'c> Foo: Send+Clone+'c`
 378 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 379 pub struct WhereBoundPredicate {
 380     pub span: Span,
 381     /// Any lifetimes from a `for` binding
 382     pub bound_lifetimes: HirVec<LifetimeDef>,
 383     /// The type being bounded
 384     pub bounded_ty: P<Ty>,
 385     /// Trait and lifetime bounds (`Clone+Send+'static`)
 386     pub bounds: TyParamBounds,
 387 }
 388
 389 /// A lifetime predicate, e.g. `'a: 'b+'c`
 390 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 391 pub struct WhereRegionPredicate {
 392     pub span: Span,
 393     pub lifetime: Lifetime,
 394     pub bounds: HirVec<Lifetime>,
 395 }
 396
 397 /// An equality predicate (unsupported), e.g. `T=int`
 398 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 399 pub struct WhereEqPredicate {
 400     pub id: NodeId,
 401     pub span: Span,
 402     pub path: Path,
 403     pub ty: P<Ty>,
 404 }
 405
 406 pub type CrateConfig = HirVec<P<MetaItem>>;
 407
 408 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
 409 pub struct Crate {
 410     pub module: Mod,
 411     pub attrs: HirVec<Attribute>,
 412     pub config: CrateConfig,
 413     pub span: Span,
 414     pub exported_macros: HirVec<MacroDef>,
 415
 416     // NB: We use a BTreeMap here so that `visit_all_items` iterates
 417     // over the ids in increasing order. In principle it should not
 418     // matter what order we visit things in, but in *practice* it
 419     // does, because it can affect the order in which errors are
 420     // detected, which in turn can make compile-fail tests yield
 421     // slightly different results.
 422     pub items: BTreeMap<NodeId, Item>,
 423 }
 424
 425 impl Crate {
 426     pub fn item(&self, id: NodeId) -> &Item {
 427         &self.items[&id]
 428     }
 429
 430     /// Visits all items in the crate in some determinstic (but
 431     /// unspecified) order. If you just need to process every item,
 432     /// but don't care about nesting, this method is the best choice.
 433     ///
 434     /// If you do care about nesting -- usually because your algorithm
 435     /// follows lexical scoping rules -- then you want a different
 436     /// approach. You should override `visit_nested_item` in your
 437     /// visitor and then call `intravisit::walk_crate` instead.
 438     pub fn visit_all_items<'hir, V:Visitor<'hir>>(&'hir self, visitor: &mut V) {
 439         for (_, item) in &self.items {
 440             visitor.visit_item(item);
 441         }
 442     }
 443 }
 444
 445 /// A macro definition, in this crate or imported from another.
 446 ///
 447 /// Not parsed directly, but created on macro import or `macro_rules!` expansion.
 448 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 449 pub struct MacroDef {
 450     pub name: Name,
 451     pub attrs: HirVec<Attribute>,
 452     pub id: NodeId,
 453     pub span: Span,
 454     pub imported_from: Option<Name>,
 455     pub export: bool,
 456     pub use_locally: bool,
 457     pub allow_internal_unstable: bool,
 458     pub body: HirVec<TokenTree>,
 459 }
 460
 461 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 462 pub struct Block {
 463     /// Statements in a block
 464     pub stmts: HirVec<Stmt>,
 465     /// An expression at the end of the block
 466     /// without a semicolon, if any
 467     pub expr: Option<P<Expr>>,
 468     pub id: NodeId,
 469     /// Distinguishes between `unsafe { ... }` and `{ ... }`
 470     pub rules: BlockCheckMode,
 471     pub span: Span,
 472 }
 473
 474 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 475 pub struct Pat {
 476     pub id: NodeId,
 477     pub node: PatKind,
 478     pub span: Span,
 479 }
 480
 481 impl fmt::Debug for Pat {
 482     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 483         write!(f, "pat({}: {})", self.id, pprust::pat_to_string(self))
 484     }
 485 }
 486
 487 /// A single field in a struct pattern
 488 ///
 489 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
 490 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
 491 /// except is_shorthand is true
 492 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 493 pub struct FieldPat {
 494     /// The identifier for the field
 495     pub name: Name,
 496     /// The pattern the field is destructured to
 497     pub pat: P<Pat>,
 498     pub is_shorthand: bool,
 499 }
 500
 501 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 502 pub enum BindingMode {
 503     BindByRef(Mutability),
 504     BindByValue(Mutability),
 505 }
 506
 507 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 508 pub enum PatKind {
 509     /// Represents a wildcard pattern (`_`)
 510     Wild,
 511
 512     /// A `PatKind::Ident` may either be a new bound variable,
 513     /// or a unit struct/variant pattern, or a const pattern (in the last two cases
 514     /// the third field must be `None`).
 515     ///
 516     /// In the unit or const pattern case, the parser can't determine
 517     /// which it is. The resolver determines this, and
 518     /// records this pattern's `NodeId` in an auxiliary
 519     /// set (of "PatIdents that refer to unit patterns or constants").
 520     Ident(BindingMode, Spanned<Ident>, Option<P<Pat>>),
 521
 522     /// A struct or struct variant pattern, e.g. `Variant {x, y, ..}`.
 523     /// The `bool` is `true` in the presence of a `..`.
 524     Struct(Path, HirVec<Spanned<FieldPat>>, bool),
 525
 526     /// A tuple struct/variant pattern `Variant(x, y, z)`.
 527     /// "None" means a `Variant(..)` pattern where we don't bind the fields to names.
 528     TupleStruct(Path, Option<HirVec<P<Pat>>>),
 529
 530     /// A path pattern.
 531     /// Such pattern can be resolved to a unit struct/variant or a constant.
 532     Path(Path),
 533
 534     /// An associated const named using the qualified path `<T>::CONST` or
 535     /// `<T as Trait>::CONST`. Associated consts from inherent impls can be
 536     /// referred to as simply `T::CONST`, in which case they will end up as
 537     /// PatKind::Path, and the resolver will have to sort that out.
 538     QPath(QSelf, Path),
 539
 540     /// A tuple pattern `(a, b)`
 541     Tup(HirVec<P<Pat>>),
 542     /// A `box` pattern
 543     Box(P<Pat>),
 544     /// A reference pattern, e.g. `&mut (a, b)`
 545     Ref(P<Pat>, Mutability),
 546     /// A literal
 547     Lit(P<Expr>),
 548     /// A range pattern, e.g. `1...2`
 549     Range(P<Expr>, P<Expr>),
 550     /// `[a, b, ..i, y, z]` is represented as:
 551     ///     `PatKind::Vec(box [a, b], Some(i), box [y, z])`
 552     Vec(HirVec<P<Pat>>, Option<P<Pat>>, HirVec<P<Pat>>),
 553 }
 554
 555 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 556 pub enum Mutability {
 557     MutMutable,
 558     MutImmutable,
 559 }
 560
 561 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 562 pub enum BinOp_ {
 563     /// The `+` operator (addition)
 564     BiAdd,
 565     /// The `-` operator (subtraction)
 566     BiSub,
 567     /// The `*` operator (multiplication)
 568     BiMul,
 569     /// The `/` operator (division)
 570     BiDiv,
 571     /// The `%` operator (modulus)
 572     BiRem,
 573     /// The `&&` operator (logical and)
 574     BiAnd,
 575     /// The `||` operator (logical or)
 576     BiOr,
 577     /// The `^` operator (bitwise xor)
 578     BiBitXor,
 579     /// The `&` operator (bitwise and)
 580     BiBitAnd,
 581     /// The `|` operator (bitwise or)
 582     BiBitOr,
 583     /// The `<<` operator (shift left)
 584     BiShl,
 585     /// The `>>` operator (shift right)
 586     BiShr,
 587     /// The `==` operator (equality)
 588     BiEq,
 589     /// The `<` operator (less than)
 590     BiLt,
 591     /// The `<=` operator (less than or equal to)
 592     BiLe,
 593     /// The `!=` operator (not equal to)
 594     BiNe,
 595     /// The `>=` operator (greater than or equal to)
 596     BiGe,
 597     /// The `>` operator (greater than)
 598     BiGt,
 599 }
 600
 601 pub type BinOp = Spanned<BinOp_>;
 602
 603 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 604 pub enum UnOp {
 605     /// The `*` operator for dereferencing
 606     UnDeref,
 607     /// The `!` operator for logical inversion
 608     UnNot,
 609     /// The `-` operator for negation
 610     UnNeg,
 611 }
 612
 613 /// A statement
 614 pub type Stmt = Spanned<Stmt_>;
 615
 616 impl fmt::Debug for Stmt_ {
 617     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 618         // Sadness.
 619         let spanned = codemap::dummy_spanned(self.clone());
 620         write!(f,
 621                "stmt({}: {})",
 622                util::stmt_id(&spanned),
 623                pprust::stmt_to_string(&spanned))
 624     }
 625 }
 626
 627 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 628 pub enum Stmt_ {
 629     /// Could be an item or a local (let) binding:
 630     StmtDecl(P<Decl>, NodeId),
 631
 632     /// Expr without trailing semi-colon (must have unit type):
 633     StmtExpr(P<Expr>, NodeId),
 634
 635     /// Expr with trailing semi-colon (may have any type):
 636     StmtSemi(P<Expr>, NodeId),
 637 }
 638
 639 // FIXME (pending discussion of #1697, #2178...): local should really be
 640 // a refinement on pat.
 641 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`
 642 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 643 pub struct Local {
 644     pub pat: P<Pat>,
 645     pub ty: Option<P<Ty>>,
 646     /// Initializer expression to set the value, if any
 647     pub init: Option<P<Expr>>,
 648     pub id: NodeId,
 649     pub span: Span,
 650     pub attrs: ThinAttributes,
 651 }
 652
 653 pub type Decl = Spanned<Decl_>;
 654
 655 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 656 pub enum Decl_ {
 657     /// A local (let) binding:
 658     DeclLocal(P<Local>),
 659     /// An item binding:
 660     DeclItem(ItemId),
 661 }
 662
 663 /// represents one arm of a 'match'
 664 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 665 pub struct Arm {
 666     pub attrs: HirVec<Attribute>,
 667     pub pats: HirVec<P<Pat>>,
 668     pub guard: Option<P<Expr>>,
 669     pub body: P<Expr>,
 670 }
 671
 672 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 673 pub struct Field {
 674     pub name: Spanned<Name>,
 675     pub expr: P<Expr>,
 676     pub span: Span,
 677 }
 678
 679 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 680 pub enum BlockCheckMode {
 681     DefaultBlock,
 682     UnsafeBlock(UnsafeSource),
 683     PushUnsafeBlock(UnsafeSource),
 684     PopUnsafeBlock(UnsafeSource),
 685     // Within this block (but outside a PopUnstableBlock), we suspend checking of stability.
 686     PushUnstableBlock,
 687     PopUnstableBlock,
 688 }
 689
 690 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 691 pub enum UnsafeSource {
 692     CompilerGenerated,
 693     UserProvided,
 694 }
 695
 696 /// An expression
 697 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 698 pub struct Expr {
 699     pub id: NodeId,
 700     pub node: Expr_,
 701     pub span: Span,
 702     pub attrs: ThinAttributes,
 703 }
 704
 705 impl fmt::Debug for Expr {
 706     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 707         write!(f, "expr({}: {})", self.id, pprust::expr_to_string(self))
 708     }
 709 }
 710
 711 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 712 pub enum Expr_ {
 713     /// A `box x` expression.
 714     ExprBox(P<Expr>),
 715     /// An array (`[a, b, c, d]`)
 716     ExprVec(HirVec<P<Expr>>),
 717     /// A function call
 718     ///
 719     /// The first field resolves to the function itself,
 720     /// and the second field is the list of arguments
 721     ExprCall(P<Expr>, HirVec<P<Expr>>),
 722     /// A method call (`x.foo::<Bar, Baz>(a, b, c, d)`)
 723     ///
 724     /// The `Spanned<Name>` is the identifier for the method name.
 725     /// The vector of `Ty`s are the ascripted type parameters for the method
 726     /// (within the angle brackets).
 727     ///
 728     /// The first element of the vector of `Expr`s is the expression that evaluates
 729     /// to the object on which the method is being called on (the receiver),
 730     /// and the remaining elements are the rest of the arguments.
 731     ///
 732     /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
 733     /// `ExprMethodCall(foo, [Bar, Baz], [x, a, b, c, d])`.
 734     ExprMethodCall(Spanned<Name>, HirVec<P<Ty>>, HirVec<P<Expr>>),
 735     /// A tuple (`(a, b, c ,d)`)
 736     ExprTup(HirVec<P<Expr>>),
 737     /// A binary operation (For example: `a + b`, `a * b`)
 738     ExprBinary(BinOp, P<Expr>, P<Expr>),
 739     /// A unary operation (For example: `!x`, `*x`)
 740     ExprUnary(UnOp, P<Expr>),
 741     /// A literal (For example: `1u8`, `"foo"`)
 742     ExprLit(P<Lit>),
 743     /// A cast (`foo as f64`)
 744     ExprCast(P<Expr>, P<Ty>),
 745     ExprType(P<Expr>, P<Ty>),
 746     /// An `if` block, with an optional else block
 747     ///
 748     /// `if expr { block } else { expr }`
 749     ExprIf(P<Expr>, P<Block>, Option<P<Expr>>),
 750     /// A while loop, with an optional label
 751     ///
 752     /// `'label: while expr { block }`
 753     ExprWhile(P<Expr>, P<Block>, Option<Ident>),
 754     /// Conditionless loop (can be exited with break, continue, or return)
 755     ///
 756     /// `'label: loop { block }`
 757     ExprLoop(P<Block>, Option<Ident>),
 758     /// A `match` block, with a source that indicates whether or not it is
 759     /// the result of a desugaring, and if so, which kind.
 760     ExprMatch(P<Expr>, HirVec<Arm>, MatchSource),
 761     /// A closure (for example, `move |a, b, c| {a + b + c}`)
 762     ExprClosure(CaptureClause, P<FnDecl>, P<Block>),
 763     /// A block (`{ ... }`)
 764     ExprBlock(P<Block>),
 765
 766     /// An assignment (`a = foo()`)
 767     ExprAssign(P<Expr>, P<Expr>),
 768     /// An assignment with an operator
 769     ///
 770     /// For example, `a += 1`.
 771     ExprAssignOp(BinOp, P<Expr>, P<Expr>),
 772     /// Access of a named struct field (`obj.foo`)
 773     ExprField(P<Expr>, Spanned<Name>),
 774     /// Access of an unnamed field of a struct or tuple-struct
 775     ///
 776     /// For example, `foo.0`.
 777     ExprTupField(P<Expr>, Spanned<usize>),
 778     /// An indexing operation (`foo[2]`)
 779     ExprIndex(P<Expr>, P<Expr>),
 780     /// A range (`1..2`, `1..`, or `..2`)
 781     ExprRange(Option<P<Expr>>, Option<P<Expr>>),
 782
 783     /// Variable reference, possibly containing `::` and/or type
 784     /// parameters, e.g. foo::bar::<baz>.
 785     ///
 786     /// Optionally "qualified",
 787     /// e.g. `<HirVec<T> as SomeTrait>::SomeType`.
 788     ExprPath(Option<QSelf>, Path),
 789
 790     /// A referencing operation (`&a` or `&mut a`)
 791     ExprAddrOf(Mutability, P<Expr>),
 792     /// A `break`, with an optional label to break
 793     ExprBreak(Option<Spanned<Ident>>),
 794     /// A `continue`, with an optional label
 795     ExprAgain(Option<Spanned<Ident>>),
 796     /// A `return`, with an optional value to be returned
 797     ExprRet(Option<P<Expr>>),
 798
 799     /// Output of the `asm!()` macro
 800     ExprInlineAsm(InlineAsm),
 801
 802     /// A struct literal expression.
 803     ///
 804     /// For example, `Foo {x: 1, y: 2}`, or
 805     /// `Foo {x: 1, .. base}`, where `base` is the `Option<Expr>`.
 806     ExprStruct(Path, HirVec<Field>, Option<P<Expr>>),
 807
 808     /// A vector literal constructed from one repeated element.
 809     ///
 810     /// For example, `[1u8; 5]`. The first expression is the element
 811     /// to be repeated; the second is the number of times to repeat it.
 812     ExprRepeat(P<Expr>, P<Expr>),
 813 }
 814
 815 /// The explicit Self type in a "qualified path". The actual
 816 /// path, including the trait and the associated item, is stored
 817 /// separately. `position` represents the index of the associated
 818 /// item qualified with this Self type.
 819 ///
 820 ///     <HirVec<T> as a::b::Trait>::AssociatedItem
 821 ///      ^~~~~     ~~~~~~~~~~~~~~^
 822 ///      ty        position = 3
 823 ///
 824 ///     <HirVec<T>>::AssociatedItem
 825 ///      ^~~~~    ^
 826 ///      ty       position = 0
 827 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 828 pub struct QSelf {
 829     pub ty: P<Ty>,
 830     pub position: usize,
 831 }
 832
 833 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 834 pub enum MatchSource {
 835     Normal,
 836     IfLetDesugar {
 837         contains_else_clause: bool,
 838     },
 839     WhileLetDesugar,
 840     ForLoopDesugar,
 841 }
 842
 843 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 844 pub enum CaptureClause {
 845     CaptureByValue,
 846     CaptureByRef,
 847 }
 848
 849 // NB: If you change this, you'll probably want to change the corresponding
 850 // type structure in middle/ty.rs as well.
 851 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 852 pub struct MutTy {
 853     pub ty: P<Ty>,
 854     pub mutbl: Mutability,
 855 }
 856
 857 /// Represents a method's signature in a trait declaration,
 858 /// or in an implementation.
 859 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 860 pub struct MethodSig {
 861     pub unsafety: Unsafety,
 862     pub constness: Constness,
 863     pub abi: Abi,
 864     pub decl: P<FnDecl>,
 865     pub generics: Generics,
 866     pub explicit_self: ExplicitSelf,
 867 }
 868
 869 /// Represents a method declaration in a trait declaration, possibly including
 870 /// a default implementation A trait method is either required (meaning it
 871 /// doesn't have an implementation, just a signature) or provided (meaning it
 872 /// has a default implementation).
 873 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 874 pub struct TraitItem {
 875     pub id: NodeId,
 876     pub name: Name,
 877     pub attrs: HirVec<Attribute>,
 878     pub node: TraitItem_,
 879     pub span: Span,
 880 }
 881
 882 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 883 pub enum TraitItem_ {
 884     ConstTraitItem(P<Ty>, Option<P<Expr>>),
 885     MethodTraitItem(MethodSig, Option<P<Block>>),
 886     TypeTraitItem(TyParamBounds, Option<P<Ty>>),
 887 }
 888
 889 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 890 pub struct ImplItem {
 891     pub id: NodeId,
 892     pub name: Name,
 893     pub vis: Visibility,
 894     pub attrs: HirVec<Attribute>,
 895     pub node: ImplItemKind,
 896     pub span: Span,
 897 }
 898
 899 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 900 pub enum ImplItemKind {
 901     Const(P<Ty>, P<Expr>),
 902     Method(MethodSig, P<Block>),
 903     Type(P<Ty>),
 904 }
 905
 906 // Bind a type to an associated type: `A=Foo`.
 907 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 908 pub struct TypeBinding {
 909     pub id: NodeId,
 910     pub name: Name,
 911     pub ty: P<Ty>,
 912     pub span: Span,
 913 }
 914
 915
 916 // NB PartialEq method appears below.
 917 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 918 pub struct Ty {
 919     pub id: NodeId,
 920     pub node: Ty_,
 921     pub span: Span,
 922 }
 923
 924 impl fmt::Debug for Ty {
 925     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 926         write!(f, "type({})", pprust::ty_to_string(self))
 927     }
 928 }
 929
 930 /// Not represented directly in the AST, referred to by name through a ty_path.
 931 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 932 pub enum PrimTy {
 933     TyInt(IntTy),
 934     TyUint(UintTy),
 935     TyFloat(FloatTy),
 936     TyStr,
 937     TyBool,
 938     TyChar,
 939 }
 940
 941 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 942 pub struct BareFnTy {
 943     pub unsafety: Unsafety,
 944     pub abi: Abi,
 945     pub lifetimes: HirVec<LifetimeDef>,
 946     pub decl: P<FnDecl>,
 947 }
 948
 949 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 950 /// The different kinds of types recognized by the compiler
 951 pub enum Ty_ {
 952     TyVec(P<Ty>),
 953     /// A fixed length array (`[T; n]`)
 954     TyFixedLengthVec(P<Ty>, P<Expr>),
 955     /// A raw pointer (`*const T` or `*mut T`)
 956     TyPtr(MutTy),
 957     /// A reference (`&'a T` or `&'a mut T`)
 958     TyRptr(Option<Lifetime>, MutTy),
 959     /// A bare function (e.g. `fn(usize) -> bool`)
 960     TyBareFn(P<BareFnTy>),
 961     /// A tuple (`(A, B, C, D,...)`)
 962     TyTup(HirVec<P<Ty>>),
 963     /// A path (`module::module::...::Type`), optionally
 964     /// "qualified", e.g. `<HirVec<T> as SomeTrait>::SomeType`.
 965     ///
 966     /// Type parameters are stored in the Path itself
 967     TyPath(Option<QSelf>, Path),
 968     /// Something like `A+B`. Note that `B` must always be a path.
 969     TyObjectSum(P<Ty>, TyParamBounds),
 970     /// A type like `for<'a> Foo<&'a Bar>`
 971     TyPolyTraitRef(TyParamBounds),
 972     /// Unused for now
 973     TyTypeof(P<Expr>),
 974     /// TyInfer means the type should be inferred instead of it having been
 975     /// specified. This can appear anywhere in a type.
 976     TyInfer,
 977 }
 978
 979 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 980 pub struct InlineAsmOutput {
 981     pub constraint: InternedString,
 982     pub expr: P<Expr>,
 983     pub is_rw: bool,
 984     pub is_indirect: bool,
 985 }
 986
 987 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 988 pub struct InlineAsm {
 989     pub asm: InternedString,
 990     pub asm_str_style: StrStyle,
 991     pub outputs: HirVec<InlineAsmOutput>,
 992     pub inputs: HirVec<(InternedString, P<Expr>)>,
 993     pub clobbers: HirVec<InternedString>,
 994     pub volatile: bool,
 995     pub alignstack: bool,
 996     pub dialect: AsmDialect,
 997     pub expn_id: ExpnId,
 998 }
 999
1000 /// represents an argument in a function header
1001 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1002 pub struct Arg {
1003     pub ty: P<Ty>,
1004     pub pat: P<Pat>,
1005     pub id: NodeId,
1006 }
1007
1008 impl Arg {
1009     pub fn new_self(span: Span, mutability: Mutability, self_ident: Ident) -> Arg {
1010         let path = Spanned {
1011             span: span,
1012             node: self_ident,
1013         };
1014         Arg {
1015             // HACK(eddyb) fake type for the self argument.
1016             ty: P(Ty {
1017                 id: DUMMY_NODE_ID,
1018                 node: TyInfer,
1019                 span: DUMMY_SP,
1020             }),
1021             pat: P(Pat {
1022                 id: DUMMY_NODE_ID,
1023                 node: PatKind::Ident(BindByValue(mutability), path, None),
1024                 span: span,
1025             }),
1026             id: DUMMY_NODE_ID,
1027         }
1028     }
1029 }
1030
1031 /// Represents the header (not the body) of a function declaration
1032 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1033 pub struct FnDecl {
1034     pub inputs: HirVec<Arg>,
1035     pub output: FunctionRetTy,
1036     pub variadic: bool,
1037 }
1038
1039 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1040 pub enum Unsafety {
1041     Unsafe,
1042     Normal,
1043 }
1044
1045 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1046 pub enum Constness {
1047     Const,
1048     NotConst,
1049 }
1050
1051 impl fmt::Display for Unsafety {
1052     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1053         fmt::Display::fmt(match *self {
1054                               Unsafety::Normal => "normal",
1055                               Unsafety::Unsafe => "unsafe",
1056                           },
1057                           f)
1058     }
1059 }
1060
1061 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
1062 pub enum ImplPolarity {
1063     /// `impl Trait for Type`
1064     Positive,
1065     /// `impl !Trait for Type`
1066     Negative,
1067 }
1068
1069 impl fmt::Debug for ImplPolarity {
1070     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1071         match *self {
1072             ImplPolarity::Positive => "positive".fmt(f),
1073             ImplPolarity::Negative => "negative".fmt(f),
1074         }
1075     }
1076 }
1077
1078
1079 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1080 pub enum FunctionRetTy {
1081     /// Functions with return type `!`that always
1082     /// raise an error or exit (i.e. never return to the caller)
1083     NoReturn(Span),
1084     /// Return type is not specified.
1085     ///
1086     /// Functions default to `()` and
1087     /// closures default to inference. Span points to where return
1088     /// type would be inserted.
1089     DefaultReturn(Span),
1090     /// Everything else
1091     Return(P<Ty>),
1092 }
1093
1094 impl FunctionRetTy {
1095     pub fn span(&self) -> Span {
1096         match *self {
1097             NoReturn(span) => span,
1098             DefaultReturn(span) => span,
1099             Return(ref ty) => ty.span,
1100         }
1101     }
1102 }
1103
1104 /// Represents the kind of 'self' associated with a method
1105 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1106 pub enum ExplicitSelf_ {
1107     /// No self
1108     SelfStatic,
1109     /// `self`
1110     SelfValue(Name),
1111     /// `&'lt self`, `&'lt mut self`
1112     SelfRegion(Option<Lifetime>, Mutability, Name),
1113     /// `self: TYPE`
1114     SelfExplicit(P<Ty>, Name),
1115 }
1116
1117 pub type ExplicitSelf = Spanned<ExplicitSelf_>;
1118
1119 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1120 pub struct Mod {
1121     /// A span from the first token past `{` to the last token until `}`.
1122     /// For `mod foo;`, the inner span ranges from the first token
1123     /// to the last token in the external file.
1124     pub inner: Span,
1125     pub item_ids: HirVec<ItemId>,
1126 }
1127
1128 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1129 pub struct ForeignMod {
1130     pub abi: Abi,
1131     pub items: HirVec<ForeignItem>,
1132 }
1133
1134 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1135 pub struct EnumDef {
1136     pub variants: HirVec<Variant>,
1137 }
1138
1139 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1140 pub struct Variant_ {
1141     pub name: Name,
1142     pub attrs: HirVec<Attribute>,
1143     pub data: VariantData,
1144     /// Explicit discriminant, eg `Foo = 1`
1145     pub disr_expr: Option<P<Expr>>,
1146 }
1147
1148 pub type Variant = Spanned<Variant_>;
1149
1150 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1151 pub enum PathListItem_ {
1152     PathListIdent {
1153         name: Name,
1154         /// renamed in list, eg `use foo::{bar as baz};`
1155         rename: Option<Name>,
1156         id: NodeId,
1157     },
1158     PathListMod {
1159         /// renamed in list, eg `use foo::{self as baz};`
1160         rename: Option<Name>,
1161         id: NodeId,
1162     },
1163 }
1164
1165 impl PathListItem_ {
1166     pub fn id(&self) -> NodeId {
1167         match *self {
1168             PathListIdent { id, .. } | PathListMod { id, .. } => id,
1169         }
1170     }
1171
1172     pub fn name(&self) -> Option<Name> {
1173         match *self {
1174             PathListIdent { name, .. } => Some(name),
1175             PathListMod { .. } => None,
1176         }
1177     }
1178
1179     pub fn rename(&self) -> Option<Name> {
1180         match *self {
1181             PathListIdent { rename, .. } | PathListMod { rename, .. } => rename,
1182         }
1183     }
1184 }
1185
1186 pub type PathListItem = Spanned<PathListItem_>;
1187
1188 pub type ViewPath = Spanned<ViewPath_>;
1189
1190 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1191 pub enum ViewPath_ {
1192     /// `foo::bar::baz as quux`
1193     ///
1194     /// or just
1195     ///
1196     /// `foo::bar::baz` (with `as baz` implicitly on the right)
1197     ViewPathSimple(Name, Path),
1198
1199     /// `foo::bar::*`
1200     ViewPathGlob(Path),
1201
1202     /// `foo::bar::{a,b,c}`
1203     ViewPathList(Path, HirVec<PathListItem>),
1204 }
1205
1206 /// TraitRef's appear in impls.
1207 ///
1208 /// resolve maps each TraitRef's ref_id to its defining trait; that's all
1209 /// that the ref_id is for. The impl_id maps to the "self type" of this impl.
1210 /// If this impl is an ItemImpl, the impl_id is redundant (it could be the
1211 /// same as the impl's node id).
1212 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1213 pub struct TraitRef {
1214     pub path: Path,
1215     pub ref_id: NodeId,
1216 }
1217
1218 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1219 pub struct PolyTraitRef {
1220     /// The `'a` in `<'a> Foo<&'a T>`
1221     pub bound_lifetimes: HirVec<LifetimeDef>,
1222
1223     /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`
1224     pub trait_ref: TraitRef,
1225
1226     pub span: Span,
1227 }
1228
1229 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1230 pub enum Visibility {
1231     Public,
1232     Inherited,
1233 }
1234
1235 impl Visibility {
1236     pub fn inherit_from(&self, parent_visibility: Visibility) -> Visibility {
1237         match self {
1238             &Inherited => parent_visibility,
1239             &Public => *self,
1240         }
1241     }
1242 }
1243
1244 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1245 pub struct StructField_ {
1246     pub kind: StructFieldKind,
1247     pub id: NodeId,
1248     pub ty: P<Ty>,
1249     pub attrs: HirVec<Attribute>,
1250 }
1251
1252 impl StructField_ {
1253     pub fn name(&self) -> Option<Name> {
1254         match self.kind {
1255             NamedField(name, _) => Some(name),
1256             UnnamedField(_) => None,
1257         }
1258     }
1259 }
1260
1261 pub type StructField = Spanned<StructField_>;
1262
1263 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
1264 pub enum StructFieldKind {
1265     NamedField(Name, Visibility),
1266     /// Element of a tuple-like struct
1267     UnnamedField(Visibility),
1268 }
1269
1270 impl StructFieldKind {
1271     pub fn is_unnamed(&self) -> bool {
1272         match *self {
1273             UnnamedField(..) => true,
1274             NamedField(..) => false,
1275         }
1276     }
1277
1278     pub fn visibility(&self) -> Visibility {
1279         match *self {
1280             NamedField(_, vis) | UnnamedField(vis) => vis,
1281         }
1282     }
1283 }
1284
1285 /// Fields and Ids of enum variants and structs
1286 ///
1287 /// For enum variants: `NodeId` represents both an Id of the variant itself (relevant for all
1288 /// variant kinds) and an Id of the variant's constructor (not relevant for `Struct`-variants).
1289 /// One shared Id can be successfully used for these two purposes.
1290 /// Id of the whole enum lives in `Item`.
1291 ///
1292 /// For structs: `NodeId` represents an Id of the structure's constructor, so it is not actually
1293 /// used for `Struct`-structs (but still presents). Structures don't have an analogue of "Id of
1294 /// the variant itself" from enum variants.
1295 /// Id of the whole struct lives in `Item`.
1296 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1297 pub enum VariantData {
1298     Struct(HirVec<StructField>, NodeId),
1299     Tuple(HirVec<StructField>, NodeId),
1300     Unit(NodeId),
1301 }
1302
1303 impl VariantData {
1304     pub fn fields(&self) -> &[StructField] {
1305         match *self {
1306             VariantData::Struct(ref fields, _) | VariantData::Tuple(ref fields, _) => fields,
1307             _ => &[],
1308         }
1309     }
1310     pub fn id(&self) -> NodeId {
1311         match *self {
1312             VariantData::Struct(_, id) | VariantData::Tuple(_, id) | VariantData::Unit(id) => id,
1313         }
1314     }
1315     pub fn is_struct(&self) -> bool {
1316         if let VariantData::Struct(..) = *self {
1317             true
1318         } else {
1319             false
1320         }
1321     }
1322     pub fn is_tuple(&self) -> bool {
1323         if let VariantData::Tuple(..) = *self {
1324             true
1325         } else {
1326             false
1327         }
1328     }
1329     pub fn is_unit(&self) -> bool {
1330         if let VariantData::Unit(..) = *self {
1331             true
1332         } else {
1333             false
1334         }
1335     }
1336 }
1337
1338 // The bodies for items are stored "out of line", in a separate
1339 // hashmap in the `Crate`. Here we just record the node-id of the item
1340 // so it can fetched later.
1341 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1342 pub struct ItemId {
1343     pub id: NodeId,
1344 }
1345
1346 //  FIXME (#3300): Should allow items to be anonymous. Right now
1347 //  we just use dummy names for anon items.
1348 /// An item
1349 ///
1350 /// The name might be a dummy name in case of anonymous items
1351 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1352 pub struct Item {
1353     pub name: Name,
1354     pub attrs: HirVec<Attribute>,
1355     pub id: NodeId,
1356     pub node: Item_,
1357     pub vis: Visibility,
1358     pub span: Span,
1359 }
1360
1361 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1362 pub enum Item_ {
1363     /// An`extern crate` item, with optional original crate name,
1364     ///
1365     /// e.g. `extern crate foo` or `extern crate foo_bar as foo`
1366     ItemExternCrate(Option<Name>),
1367     /// A `use` or `pub use` item
1368     ItemUse(P<ViewPath>),
1369
1370     /// A `static` item
1371     ItemStatic(P<Ty>, Mutability, P<Expr>),
1372     /// A `const` item
1373     ItemConst(P<Ty>, P<Expr>),
1374     /// A function declaration
1375     ItemFn(P<FnDecl>, Unsafety, Constness, Abi, Generics, P<Block>),
1376     /// A module
1377     ItemMod(Mod),
1378     /// An external module
1379     ItemForeignMod(ForeignMod),
1380     /// A type alias, e.g. `type Foo = Bar<u8>`
1381     ItemTy(P<Ty>, Generics),
1382     /// An enum definition, e.g. `enum Foo<A, B> {C<A>, D<B>}`
1383     ItemEnum(EnumDef, Generics),
1384     /// A struct definition, e.g. `struct Foo<A> {x: A}`
1385     ItemStruct(VariantData, Generics),
1386     /// Represents a Trait Declaration
1387     ItemTrait(Unsafety, Generics, TyParamBounds, HirVec<TraitItem>),
1388
1389     // Default trait implementations
1390     ///
1391     /// `impl Trait for .. {}`
1392     ItemDefaultImpl(Unsafety, TraitRef),
1393     /// An implementation, eg `impl<A> Trait for Foo { .. }`
1394     ItemImpl(Unsafety,
1395              ImplPolarity,
1396              Generics,
1397              Option<TraitRef>, // (optional) trait this impl implements
1398              P<Ty>, // self
1399              HirVec<ImplItem>),
1400 }
1401
1402 impl Item_ {
1403     pub fn descriptive_variant(&self) -> &str {
1404         match *self {
1405             ItemExternCrate(..) => "extern crate",
1406             ItemUse(..) => "use",
1407             ItemStatic(..) => "static item",
1408             ItemConst(..) => "constant item",
1409             ItemFn(..) => "function",
1410             ItemMod(..) => "module",
1411             ItemForeignMod(..) => "foreign module",
1412             ItemTy(..) => "type alias",
1413             ItemEnum(..) => "enum",
1414             ItemStruct(..) => "struct",
1415             ItemTrait(..) => "trait",
1416             ItemImpl(..) |
1417             ItemDefaultImpl(..) => "item",
1418         }
1419     }
1420 }
1421
1422 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1423 pub struct ForeignItem {
1424     pub name: Name,
1425     pub attrs: HirVec<Attribute>,
1426     pub node: ForeignItem_,
1427     pub id: NodeId,
1428     pub span: Span,
1429     pub vis: Visibility,
1430 }
1431
1432 /// An item within an `extern` block
1433 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
1434 pub enum ForeignItem_ {
1435     /// A foreign function
1436     ForeignItemFn(P<FnDecl>, Generics),
1437     /// A foreign static item (`static ext: u8`), with optional mutability
1438     /// (the boolean is true when mutable)
1439     ForeignItemStatic(P<Ty>, bool),
1440 }
1441
1442 impl ForeignItem_ {
1443     pub fn descriptive_variant(&self) -> &str {
1444         match *self {
1445             ForeignItemFn(..) => "foreign function",
1446             ForeignItemStatic(..) => "foreign static item",
1447         }
1448     }
1449 }