1 //! The Rust abstract syntax tree module.
3 //! This module contains common structures forming the language AST.
4 //! Two main entities in the module are [`Item`] (which represents an AST element with
5 //! additional metadata), and [`ItemKind`] (which represents a concrete type and contains
6 //! information specific to the type of the item).
8 //! Other module items that worth mentioning:
9 //! - [`Ty`] and [`TyKind`]: A parsed Rust type.
10 //! - [`Expr`] and [`ExprKind`]: A parsed Rust expression.
11 //! - [`Pat`] and [`PatKind`]: A parsed Rust pattern. Patterns are often dual to expressions.
12 //! - [`Stmt`] and [`StmtKind`]: An executable action that does not return a value.
13 //! - [`FnDecl`], [`FnHeader`] and [`Param`]: Metadata associated with a function declaration.
14 //! - [`Generics`], [`GenericParam`], [`WhereClause`]: Metadata associated with generic parameters.
15 //! - [`EnumDef`] and [`Variant`]: Enum declaration.
16 //! - [`Lit`] and [`LitKind`]: Literal expressions.
17 //! - [`MacroDef`], [`MacStmtStyle`], [`Mac`], [`MacDelimeter`]: Macro definition and invocation.
18 //! - [`Attribute`]: Metadata associated with item.
19 //! - [`UnOp`], [`UnOpKind`], [`BinOp`], [`BinOpKind`]: Unary and binary operators.
21 pub use crate::util::parser::ExprPrecedence;
22 pub use GenericArgs::*;
23 pub use UnsafeSource::*;
25 pub use rustc_span::symbol::{Ident, Symbol as Name};
28 use crate::token::{self, DelimToken};
29 use crate::tokenstream::{DelimSpan, TokenStream, TokenTree};
31 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
32 use rustc_data_structures::sync::Lrc;
33 use rustc_data_structures::thin_vec::ThinVec;
34 use rustc_index::vec::Idx;
35 use rustc_macros::HashStable_Generic;
36 use rustc_serialize::{self, Decoder, Encoder};
37 use rustc_span::source_map::{respan, Spanned};
38 use rustc_span::symbol::{kw, sym, Symbol};
39 use rustc_span::{Span, DUMMY_SP};
47 /// A "Label" is an identifier of some point in sources,
48 /// e.g. in the following code:
56 /// `'outer` is a label.
57 #[derive(Clone, RustcEncodable, RustcDecodable, Copy, HashStable_Generic)]
62 impl fmt::Debug for Label {
63 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
64 write!(f, "label({:?})", self.ident)
68 /// A "Lifetime" is an annotation of the scope in which variable
69 /// can be used, e.g. `'a` in `&'a i32`.
70 #[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
76 impl fmt::Debug for Lifetime {
77 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
78 write!(f, "lifetime({}: {})", self.id, self)
82 impl fmt::Display for Lifetime {
83 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
84 write!(f, "{}", self.ident.name)
88 /// A "Path" is essentially Rust's notion of a name.
90 /// It's represented as a sequence of identifiers,
91 /// along with a bunch of supporting information.
93 /// E.g., `std::cmp::PartialEq`.
94 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
97 /// The segments in the path: the things separated by `::`.
98 /// Global paths begin with `kw::PathRoot`.
99 pub segments: Vec<PathSegment>,
102 impl PartialEq<Symbol> for Path {
103 fn eq(&self, symbol: &Symbol) -> bool {
104 self.segments.len() == 1 && { self.segments[0].ident.name == *symbol }
108 impl<CTX> HashStable<CTX> for Path {
109 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
110 self.segments.len().hash_stable(hcx, hasher);
111 for segment in &self.segments {
112 segment.ident.name.hash_stable(hcx, hasher);
118 // Convert a span and an identifier to the corresponding
120 pub fn from_ident(ident: Ident) -> Path {
121 Path { segments: vec![PathSegment::from_ident(ident)], span: ident.span }
124 pub fn is_global(&self) -> bool {
125 !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
129 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
131 /// E.g., `std`, `String` or `Box<T>`.
132 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
133 pub struct PathSegment {
134 /// The identifier portion of this path segment.
139 /// Type/lifetime parameters attached to this path. They come in
140 /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
141 /// `None` means that no parameter list is supplied (`Path`),
142 /// `Some` means that parameter list is supplied (`Path<X, Y>`)
143 /// but it can be empty (`Path<>`).
144 /// `P` is used as a size optimization for the common case with no parameters.
145 pub args: Option<P<GenericArgs>>,
149 pub fn from_ident(ident: Ident) -> Self {
150 PathSegment { ident, id: DUMMY_NODE_ID, args: None }
152 pub fn path_root(span: Span) -> Self {
153 PathSegment::from_ident(Ident::new(kw::PathRoot, span))
157 /// The arguments of a path segment.
159 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
160 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
161 pub enum GenericArgs {
162 /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
163 AngleBracketed(AngleBracketedArgs),
164 /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
165 Parenthesized(ParenthesizedArgs),
169 pub fn is_parenthesized(&self) -> bool {
171 Parenthesized(..) => true,
176 pub fn is_angle_bracketed(&self) -> bool {
178 AngleBracketed(..) => true,
183 pub fn span(&self) -> Span {
185 AngleBracketed(ref data) => data.span,
186 Parenthesized(ref data) => data.span,
191 /// Concrete argument in the sequence of generic args.
192 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
193 pub enum GenericArg {
194 /// `'a` in `Foo<'a>`
196 /// `Bar` in `Foo<Bar>`
203 pub fn span(&self) -> Span {
205 GenericArg::Lifetime(lt) => lt.ident.span,
206 GenericArg::Type(ty) => ty.span,
207 GenericArg::Const(ct) => ct.value.span,
212 /// A path like `Foo<'a, T>`.
213 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Default)]
214 pub struct AngleBracketedArgs {
215 /// The overall span.
217 /// The arguments for this path segment.
218 pub args: Vec<GenericArg>,
219 /// Constraints on associated types, if any.
220 /// E.g., `Foo<A = Bar, B: Baz>`.
221 pub constraints: Vec<AssocTyConstraint>,
224 impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
225 fn into(self) -> Option<P<GenericArgs>> {
226 Some(P(GenericArgs::AngleBracketed(self)))
230 impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
231 fn into(self) -> Option<P<GenericArgs>> {
232 Some(P(GenericArgs::Parenthesized(self)))
236 /// A path like `Foo(A, B) -> C`.
237 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
238 pub struct ParenthesizedArgs {
243 pub inputs: Vec<P<Ty>>,
246 pub output: FunctionRetTy,
249 impl ParenthesizedArgs {
250 pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
253 args: self.inputs.iter().cloned().map(|input| GenericArg::Type(input)).collect(),
259 pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
261 /// A modifier on a bound, e.g., `?Sized` or `?const Trait`.
263 /// Negative bounds should also be handled here.
264 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
265 pub enum TraitBoundModifier {
277 // This parses but will be rejected during AST validation.
281 /// The AST represents all type param bounds as types.
282 /// `typeck::collect::compute_bounds` matches these against
283 /// the "special" built-in traits (see `middle::lang_items`) and
284 /// detects `Copy`, `Send` and `Sync`.
285 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
286 pub enum GenericBound {
287 Trait(PolyTraitRef, TraitBoundModifier),
292 pub fn span(&self) -> Span {
294 &GenericBound::Trait(ref t, ..) => t.span,
295 &GenericBound::Outlives(ref l) => l.ident.span,
300 pub type GenericBounds = Vec<GenericBound>;
302 /// Specifies the enforced ordering for generic parameters. In the future,
303 /// if we wanted to relax this order, we could override `PartialEq` and
304 /// `PartialOrd`, to allow the kinds to be unordered.
305 #[derive(PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
306 pub enum ParamKindOrd {
312 impl fmt::Display for ParamKindOrd {
313 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
315 ParamKindOrd::Lifetime => "lifetime".fmt(f),
316 ParamKindOrd::Type => "type".fmt(f),
317 ParamKindOrd::Const => "const".fmt(f),
322 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
323 pub enum GenericParamKind {
324 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
327 default: Option<P<Ty>>,
334 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
335 pub struct GenericParam {
339 pub bounds: GenericBounds,
340 pub is_placeholder: bool,
341 pub kind: GenericParamKind,
344 /// Represents lifetime, type and const parameters attached to a declaration of
345 /// a function, enum, trait, etc.
346 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
347 pub struct Generics {
348 pub params: Vec<GenericParam>,
349 pub where_clause: WhereClause,
353 impl Default for Generics {
354 /// Creates an instance of `Generics`.
355 fn default() -> Generics {
358 where_clause: WhereClause { predicates: Vec::new(), span: DUMMY_SP },
364 /// A where-clause in a definition.
365 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
366 pub struct WhereClause {
367 pub predicates: Vec<WherePredicate>,
371 /// A single predicate in a where-clause.
372 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
373 pub enum WherePredicate {
374 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
375 BoundPredicate(WhereBoundPredicate),
376 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
377 RegionPredicate(WhereRegionPredicate),
378 /// An equality predicate (unsupported).
379 EqPredicate(WhereEqPredicate),
382 impl WherePredicate {
383 pub fn span(&self) -> Span {
385 &WherePredicate::BoundPredicate(ref p) => p.span,
386 &WherePredicate::RegionPredicate(ref p) => p.span,
387 &WherePredicate::EqPredicate(ref p) => p.span,
394 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
395 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
396 pub struct WhereBoundPredicate {
398 /// Any generics from a `for` binding.
399 pub bound_generic_params: Vec<GenericParam>,
400 /// The type being bounded.
401 pub bounded_ty: P<Ty>,
402 /// Trait and lifetime bounds (`Clone + Send + 'static`).
403 pub bounds: GenericBounds,
406 /// A lifetime predicate.
408 /// E.g., `'a: 'b + 'c`.
409 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
410 pub struct WhereRegionPredicate {
412 pub lifetime: Lifetime,
413 pub bounds: GenericBounds,
416 /// An equality predicate (unsupported).
419 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
420 pub struct WhereEqPredicate {
427 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
430 pub attrs: Vec<Attribute>,
432 pub proc_macros: Vec<NodeId>,
435 /// Possible values inside of compile-time attribute lists.
437 /// E.g., the '..' in `#[name(..)]`.
438 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
439 pub enum NestedMetaItem {
440 /// A full MetaItem, for recursive meta items.
444 /// E.g., `"foo"`, `64`, `true`.
448 /// A spanned compile-time attribute item.
450 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
451 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
452 pub struct MetaItem {
454 pub kind: MetaItemKind,
458 /// A compile-time attribute item.
460 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
461 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
462 pub enum MetaItemKind {
465 /// E.g., `test` as in `#[test]`.
469 /// E.g., `derive(..)` as in `#[derive(..)]`.
470 List(Vec<NestedMetaItem>),
471 /// Name value meta item.
473 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
477 /// A block (`{ .. }`).
479 /// E.g., `{ .. }` as in `fn foo() { .. }`.
480 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
482 /// The statements in the block.
483 pub stmts: Vec<Stmt>,
485 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
486 pub rules: BlockCheckMode,
490 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
498 /// Attempt reparsing the pattern as a type.
499 /// This is intended for use by diagnostics.
500 pub fn to_ty(&self) -> Option<P<Ty>> {
501 let kind = match &self.kind {
502 // In a type expression `_` is an inference variable.
503 PatKind::Wild => TyKind::Infer,
504 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
505 PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
506 TyKind::Path(None, Path::from_ident(*ident))
508 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
509 PatKind::Mac(mac) => TyKind::Mac(mac.clone()),
510 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
511 PatKind::Ref(pat, mutbl) => {
512 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
514 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
515 // when `P` can be reparsed as a type `T`.
516 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
517 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
518 // assuming `T0` to `Tn` are all syntactically valid as types.
519 PatKind::Tuple(pats) => {
520 let mut tys = Vec::with_capacity(pats.len());
521 // FIXME(#48994) - could just be collected into an Option<Vec>
523 tys.push(pat.to_ty()?);
530 Some(P(Ty { kind, id: self.id, span: self.span }))
533 /// Walk top-down and call `it` in each place where a pattern occurs
534 /// starting with the root pattern `walk` is called on. If `it` returns
535 /// false then we will descend no further but siblings will be processed.
536 pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
542 // Walk into the pattern associated with `Ident` (if any).
543 PatKind::Ident(_, _, Some(p)) => p.walk(it),
545 // Walk into each field of struct.
546 PatKind::Struct(_, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
548 // Sequence of patterns.
549 PatKind::TupleStruct(_, s) | PatKind::Tuple(s) | PatKind::Slice(s) | PatKind::Or(s) => {
550 s.iter().for_each(|p| p.walk(it))
553 // Trivial wrappers over inner patterns.
554 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
556 // These patterns do not contain subpatterns, skip.
563 | PatKind::Mac(_) => {}
567 /// Is this a `..` pattern?
568 pub fn is_rest(&self) -> bool {
570 PatKind::Rest => true,
576 /// A single field in a struct pattern
578 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
579 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
580 /// except is_shorthand is true
581 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
582 pub struct FieldPat {
583 /// The identifier for the field
585 /// The pattern the field is destructured to
587 pub is_shorthand: bool,
591 pub is_placeholder: bool,
594 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
595 pub enum BindingMode {
600 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
602 Included(RangeSyntax),
606 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
607 pub enum RangeSyntax {
614 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
616 /// Represents a wildcard pattern (`_`).
619 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
620 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
621 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
622 /// during name resolution.
623 Ident(BindingMode, Ident, Option<P<Pat>>),
625 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
626 /// The `bool` is `true` in the presence of a `..`.
627 Struct(Path, Vec<FieldPat>, /* recovered */ bool),
629 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
630 TupleStruct(Path, Vec<P<Pat>>),
632 /// An or-pattern `A | B | C`.
633 /// Invariant: `pats.len() >= 2`.
636 /// A possibly qualified path pattern.
637 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
638 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
639 /// only legally refer to associated constants.
640 Path(Option<QSelf>, Path),
642 /// A tuple pattern (`(a, b)`).
648 /// A reference pattern (e.g., `&mut (a, b)`).
649 Ref(P<Pat>, Mutability),
654 /// A range pattern (e.g., `1...2`, `1..=2` or `1..2`).
655 Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
657 /// A slice pattern `[a, b, c]`.
660 /// A rest pattern `..`.
662 /// Syntactically it is valid anywhere.
664 /// Semantically however, it only has meaning immediately inside:
665 /// - a slice pattern: `[a, .., b]`,
666 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
667 /// - a tuple pattern: `(a, .., b)`,
668 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
670 /// In all of these cases, an additional restriction applies,
671 /// only one rest pattern may occur in the pattern sequences.
674 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
677 /// A macro pattern; pre-expansion.
694 pub enum Mutability {
700 /// Returns `MutMutable` only if both `self` and `other` are mutable.
701 pub fn and(self, other: Self) -> Self {
703 Mutability::Mut => other,
704 Mutability::Not => Mutability::Not,
708 pub fn invert(self) -> Self {
710 Mutability::Mut => Mutability::Not,
711 Mutability::Not => Mutability::Mut,
715 pub fn prefix_str(&self) -> &'static str {
717 Mutability::Mut => "mut ",
718 Mutability::Not => "",
723 /// The kind of borrow in an `AddrOf` expression,
724 /// e.g., `&place` or `&raw const place`.
725 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
726 #[derive(RustcEncodable, RustcDecodable, HashStable_Generic)]
727 pub enum BorrowKind {
728 /// A normal borrow, `&$expr` or `&mut $expr`.
729 /// The resulting type is either `&'a T` or `&'a mut T`
730 /// where `T = typeof($expr)` and `'a` is some lifetime.
732 /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
733 /// The resulting type is either `*const T` or `*mut T`
734 /// where `T = typeof($expr)`.
738 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
740 /// The `+` operator (addition)
742 /// The `-` operator (subtraction)
744 /// The `*` operator (multiplication)
746 /// The `/` operator (division)
748 /// The `%` operator (modulus)
750 /// The `&&` operator (logical and)
752 /// The `||` operator (logical or)
754 /// The `^` operator (bitwise xor)
756 /// The `&` operator (bitwise and)
758 /// The `|` operator (bitwise or)
760 /// The `<<` operator (shift left)
762 /// The `>>` operator (shift right)
764 /// The `==` operator (equality)
766 /// The `<` operator (less than)
768 /// The `<=` operator (less than or equal to)
770 /// The `!=` operator (not equal to)
772 /// The `>=` operator (greater than or equal to)
774 /// The `>` operator (greater than)
779 pub fn to_string(&self) -> &'static str {
802 pub fn lazy(&self) -> bool {
804 BinOpKind::And | BinOpKind::Or => true,
809 pub fn is_shift(&self) -> bool {
811 BinOpKind::Shl | BinOpKind::Shr => true,
816 pub fn is_comparison(&self) -> bool {
818 // Note for developers: please keep this as is;
819 // we want compilation to fail if another variant is added.
821 Eq | Lt | Le | Ne | Gt | Ge => true,
822 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
826 /// Returns `true` if the binary operator takes its arguments by value
827 pub fn is_by_value(&self) -> bool {
828 !self.is_comparison()
832 pub type BinOp = Spanned<BinOpKind>;
836 /// Note that `&data` is not an operator, it's an `AddrOf` expression.
837 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
839 /// The `*` operator for dereferencing
841 /// The `!` operator for logical inversion
843 /// The `-` operator for negation
848 /// Returns `true` if the unary operator takes its argument by value
849 pub fn is_by_value(u: UnOp) -> bool {
851 UnOp::Neg | UnOp::Not => true,
856 pub fn to_string(op: UnOp) -> &'static str {
866 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
874 pub fn add_trailing_semicolon(mut self) -> Self {
875 self.kind = match self.kind {
876 StmtKind::Expr(expr) => StmtKind::Semi(expr),
877 StmtKind::Mac(mac) => {
878 StmtKind::Mac(mac.map(|(mac, _style, attrs)| (mac, MacStmtStyle::Semicolon, attrs)))
885 pub fn is_item(&self) -> bool {
887 StmtKind::Item(_) => true,
892 pub fn is_expr(&self) -> bool {
894 StmtKind::Expr(_) => true,
900 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
902 /// A local (let) binding.
904 /// An item definition.
906 /// Expr without trailing semi-colon.
908 /// Expr with a trailing semi-colon.
911 Mac(P<(Mac, MacStmtStyle, AttrVec)>),
914 #[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
915 pub enum MacStmtStyle {
916 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
917 /// `foo!(...);`, `foo![...];`).
919 /// The macro statement had braces (e.g., `foo! { ... }`).
921 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
922 /// `foo!(...)`). All of these will end up being converted into macro
927 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
928 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
932 pub ty: Option<P<Ty>>,
933 /// Initializer expression to set the value, if any.
934 pub init: Option<P<Expr>>,
939 /// An arm of a 'match'.
941 /// E.g., `0..=10 => { println!("match!") }` as in
945 /// 0..=10 => { println!("match!") },
946 /// _ => { println!("no match!") },
949 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
951 pub attrs: Vec<Attribute>,
952 /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
954 /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
955 pub guard: Option<P<Expr>>,
960 pub is_placeholder: bool,
963 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
964 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
971 pub is_shorthand: bool,
972 pub is_placeholder: bool,
975 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
976 pub enum BlockCheckMode {
978 Unsafe(UnsafeSource),
981 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
982 pub enum UnsafeSource {
987 /// A constant (expression) that's not an item or associated item,
988 /// but needs its own `DefId` for type-checking, const-eval, etc.
989 /// These are usually found nested inside types (e.g., array lengths)
990 /// or expressions (e.g., repeat counts), and also used to define
991 /// explicit discriminant values for enum variants.
992 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
993 pub struct AnonConst {
999 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1007 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
1008 #[cfg(target_arch = "x86_64")]
1009 rustc_data_structures::static_assert_size!(Expr, 96);
1012 /// Returns `true` if this expression would be valid somewhere that expects a value;
1013 /// for example, an `if` condition.
1014 pub fn returns(&self) -> bool {
1015 if let ExprKind::Block(ref block, _) = self.kind {
1016 match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
1018 Some(&StmtKind::Expr(_)) => true,
1019 Some(&StmtKind::Semi(ref expr)) => {
1020 if let ExprKind::Ret(_) = expr.kind {
1021 // Last statement is explicit return.
1027 // This is a block that doesn't end in either an implicit or explicit return.
1031 // This is not a block, it is a value.
1036 pub fn to_bound(&self) -> Option<GenericBound> {
1038 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1039 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1040 TraitBoundModifier::None,
1046 /// Attempts to reparse as `Ty` (for diagnostic purposes).
1047 pub fn to_ty(&self) -> Option<P<Ty>> {
1048 let kind = match &self.kind {
1049 // Trivial conversions.
1050 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1051 ExprKind::Mac(mac) => TyKind::Mac(mac.clone()),
1053 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1055 ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
1056 expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
1059 ExprKind::Repeat(expr, expr_len) => {
1060 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1063 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1065 ExprKind::Tup(exprs) => {
1066 let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
1070 // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
1071 // then type of result is trait object.
1072 // Othewise we don't assume the result type.
1073 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1074 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1075 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1081 // This expression doesn't look like a type syntactically.
1085 Some(P(Ty { kind, id: self.id, span: self.span }))
1088 pub fn precedence(&self) -> ExprPrecedence {
1090 ExprKind::Box(_) => ExprPrecedence::Box,
1091 ExprKind::Array(_) => ExprPrecedence::Array,
1092 ExprKind::Call(..) => ExprPrecedence::Call,
1093 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1094 ExprKind::Tup(_) => ExprPrecedence::Tup,
1095 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1096 ExprKind::Unary(..) => ExprPrecedence::Unary,
1097 ExprKind::Lit(_) => ExprPrecedence::Lit,
1098 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1099 ExprKind::Let(..) => ExprPrecedence::Let,
1100 ExprKind::If(..) => ExprPrecedence::If,
1101 ExprKind::While(..) => ExprPrecedence::While,
1102 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1103 ExprKind::Loop(..) => ExprPrecedence::Loop,
1104 ExprKind::Match(..) => ExprPrecedence::Match,
1105 ExprKind::Closure(..) => ExprPrecedence::Closure,
1106 ExprKind::Block(..) => ExprPrecedence::Block,
1107 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1108 ExprKind::Async(..) => ExprPrecedence::Async,
1109 ExprKind::Await(..) => ExprPrecedence::Await,
1110 ExprKind::Assign(..) => ExprPrecedence::Assign,
1111 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1112 ExprKind::Field(..) => ExprPrecedence::Field,
1113 ExprKind::Index(..) => ExprPrecedence::Index,
1114 ExprKind::Range(..) => ExprPrecedence::Range,
1115 ExprKind::Path(..) => ExprPrecedence::Path,
1116 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1117 ExprKind::Break(..) => ExprPrecedence::Break,
1118 ExprKind::Continue(..) => ExprPrecedence::Continue,
1119 ExprKind::Ret(..) => ExprPrecedence::Ret,
1120 ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
1121 ExprKind::Mac(..) => ExprPrecedence::Mac,
1122 ExprKind::Struct(..) => ExprPrecedence::Struct,
1123 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1124 ExprKind::Paren(..) => ExprPrecedence::Paren,
1125 ExprKind::Try(..) => ExprPrecedence::Try,
1126 ExprKind::Yield(..) => ExprPrecedence::Yield,
1127 ExprKind::Err => ExprPrecedence::Err,
1132 /// Limit types of a range (inclusive or exclusive)
1133 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1134 pub enum RangeLimits {
1135 /// Inclusive at the beginning, exclusive at the end
1137 /// Inclusive at the beginning and end
1141 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1143 /// A `box x` expression.
1145 /// An array (`[a, b, c, d]`)
1146 Array(Vec<P<Expr>>),
1149 /// The first field resolves to the function itself,
1150 /// and the second field is the list of arguments.
1151 /// This also represents calling the constructor of
1152 /// tuple-like ADTs such as tuple structs and enum variants.
1153 Call(P<Expr>, Vec<P<Expr>>),
1154 /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1156 /// The `PathSegment` represents the method name and its generic arguments
1157 /// (within the angle brackets).
1158 /// The first element of the vector of an `Expr` is the expression that evaluates
1159 /// to the object on which the method is being called on (the receiver),
1160 /// and the remaining elements are the rest of the arguments.
1161 /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1162 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
1163 MethodCall(PathSegment, Vec<P<Expr>>),
1164 /// A tuple (e.g., `(a, b, c, d)`).
1166 /// A binary operation (e.g., `a + b`, `a * b`).
1167 Binary(BinOp, P<Expr>, P<Expr>),
1168 /// A unary operation (e.g., `!x`, `*x`).
1169 Unary(UnOp, P<Expr>),
1170 /// A literal (e.g., `1`, `"foo"`).
1172 /// A cast (e.g., `foo as f64`).
1173 Cast(P<Expr>, P<Ty>),
1174 /// A type ascription (e.g., `42: usize`).
1175 Type(P<Expr>, P<Ty>),
1176 /// A `let pat = expr` expression that is only semantically allowed in the condition
1177 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1178 Let(P<Pat>, P<Expr>),
1179 /// An `if` block, with an optional `else` block.
1181 /// `if expr { block } else { expr }`
1182 If(P<Expr>, P<Block>, Option<P<Expr>>),
1183 /// A while loop, with an optional label.
1185 /// `'label: while expr { block }`
1186 While(P<Expr>, P<Block>, Option<Label>),
1187 /// A `for` loop, with an optional label.
1189 /// `'label: for pat in expr { block }`
1191 /// This is desugared to a combination of `loop` and `match` expressions.
1192 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1193 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1195 /// `'label: loop { block }`
1196 Loop(P<Block>, Option<Label>),
1197 /// A `match` block.
1198 Match(P<Expr>, Vec<Arm>),
1199 /// A closure (e.g., `move |a, b, c| a + b + c`).
1201 /// The final span is the span of the argument block `|...|`.
1202 Closure(CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
1203 /// A block (`'label: { ... }`).
1204 Block(P<Block>, Option<Label>),
1205 /// An async block (`async move { ... }`).
1207 /// The `NodeId` is the `NodeId` for the closure that results from
1208 /// desugaring an async block, just like the NodeId field in the
1209 /// `Async::Yes` variant. This is necessary in order to create a def for the
1210 /// closure which can be used as a parent of any child defs. Defs
1211 /// created during lowering cannot be made the parent of any other
1212 /// preexisting defs.
1213 Async(CaptureBy, NodeId, P<Block>),
1214 /// An await expression (`my_future.await`).
1217 /// A try block (`try { ... }`).
1220 /// An assignment (`a = foo()`).
1221 /// The `Span` argument is the span of the `=` token.
1222 Assign(P<Expr>, P<Expr>, Span),
1223 /// An assignment with an operator.
1226 AssignOp(BinOp, P<Expr>, P<Expr>),
1227 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1228 Field(P<Expr>, Ident),
1229 /// An indexing operation (e.g., `foo[2]`).
1230 Index(P<Expr>, P<Expr>),
1231 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
1232 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1234 /// Variable reference, possibly containing `::` and/or type
1235 /// parameters (e.g., `foo::bar::<baz>`).
1237 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1238 Path(Option<QSelf>, Path),
1240 /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
1241 AddrOf(BorrowKind, Mutability, P<Expr>),
1242 /// A `break`, with an optional label to break, and an optional expression.
1243 Break(Option<Label>, Option<P<Expr>>),
1244 /// A `continue`, with an optional label.
1245 Continue(Option<Label>),
1246 /// A `return`, with an optional value to be returned.
1247 Ret(Option<P<Expr>>),
1249 /// Output of the `asm!()` macro.
1250 InlineAsm(P<InlineAsm>),
1252 /// A macro invocation; pre-expansion.
1255 /// A struct literal expression.
1257 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. base}`,
1258 /// where `base` is the `Option<Expr>`.
1259 Struct(Path, Vec<Field>, Option<P<Expr>>),
1261 /// An array literal constructed from one repeated element.
1263 /// E.g., `[1; 5]`. The expression is the element to be
1264 /// repeated; the constant is the number of times to repeat it.
1265 Repeat(P<Expr>, AnonConst),
1267 /// No-op: used solely so we can pretty-print faithfully.
1270 /// A try expression (`expr?`).
1273 /// A `yield`, with an optional value to be yielded.
1274 Yield(Option<P<Expr>>),
1276 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1280 /// The explicit `Self` type in a "qualified path". The actual
1281 /// path, including the trait and the associated item, is stored
1282 /// separately. `position` represents the index of the associated
1283 /// item qualified with this `Self` type.
1285 /// ```ignore (only-for-syntax-highlight)
1286 /// <Vec<T> as a::b::Trait>::AssociatedItem
1287 /// ^~~~~ ~~~~~~~~~~~~~~^
1290 /// <Vec<T>>::AssociatedItem
1294 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1298 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1299 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1300 /// 0`, this is an empty span.
1301 pub path_span: Span,
1302 pub position: usize,
1305 /// A capture clause used in closures and `async` blocks.
1306 #[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
1307 pub enum CaptureBy {
1308 /// `move |x| y + x`.
1310 /// `move` keyword was not specified.
1314 /// The movability of a generator / closure literal:
1315 /// whether a generator contains self-references, causing it to be `!Unpin`.
1329 pub enum Movability {
1330 /// May contain self-references, `!Unpin`.
1332 /// Must not contain self-references, `Unpin`.
1336 /// Represents a macro invocation. The `path` indicates which macro
1337 /// is being invoked, and the `args` are arguments passed to it.
1338 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1341 pub args: P<MacArgs>,
1342 pub prior_type_ascription: Option<(Span, bool)>,
1346 pub fn span(&self) -> Span {
1347 self.path.span.to(self.args.span().unwrap_or(self.path.span))
1351 /// Arguments passed to an attribute or a function-like macro.
1352 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
1354 /// No arguments - `#[attr]`.
1356 /// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
1357 Delimited(DelimSpan, MacDelimiter, TokenStream),
1358 /// Arguments of a key-value attribute - `#[attr = "value"]`.
1360 /// Span of the `=` token.
1362 /// Token stream of the "value".
1368 pub fn delim(&self) -> DelimToken {
1370 MacArgs::Delimited(_, delim, _) => delim.to_token(),
1371 MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
1375 pub fn span(&self) -> Option<Span> {
1377 MacArgs::Empty => None,
1378 MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
1379 MacArgs::Eq(eq_span, ref tokens) => Some(eq_span.to(tokens.span().unwrap_or(eq_span))),
1383 /// Tokens inside the delimiters or after `=`.
1384 /// Proc macros see these tokens, for example.
1385 pub fn inner_tokens(&self) -> TokenStream {
1387 MacArgs::Empty => TokenStream::default(),
1388 MacArgs::Delimited(.., tokens) | MacArgs::Eq(.., tokens) => tokens.clone(),
1392 /// Tokens together with the delimiters or `=`.
1393 /// Use of this method generally means that something suboptimal or hacky is happening.
1394 pub fn outer_tokens(&self) -> TokenStream {
1396 MacArgs::Empty => TokenStream::default(),
1397 MacArgs::Delimited(dspan, delim, ref tokens) => {
1398 TokenTree::Delimited(dspan, delim.to_token(), tokens.clone()).into()
1400 MacArgs::Eq(eq_span, ref tokens) => {
1401 iter::once(TokenTree::token(token::Eq, eq_span)).chain(tokens.trees()).collect()
1406 /// Whether a macro with these arguments needs a semicolon
1407 /// when used as a standalone item or statement.
1408 pub fn need_semicolon(&self) -> bool {
1409 !matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
1413 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
1414 pub enum MacDelimiter {
1421 pub fn to_token(self) -> DelimToken {
1423 MacDelimiter::Parenthesis => DelimToken::Paren,
1424 MacDelimiter::Bracket => DelimToken::Bracket,
1425 MacDelimiter::Brace => DelimToken::Brace,
1429 pub fn from_token(delim: DelimToken) -> Option<MacDelimiter> {
1431 token::Paren => Some(MacDelimiter::Parenthesis),
1432 token::Bracket => Some(MacDelimiter::Bracket),
1433 token::Brace => Some(MacDelimiter::Brace),
1434 token::NoDelim => None,
1439 /// Represents a macro definition.
1440 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1441 pub struct MacroDef {
1442 pub body: P<MacArgs>,
1443 /// `true` if macro was defined with `macro_rules`.
1447 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy, Hash, Eq, PartialEq)]
1448 #[derive(HashStable_Generic)]
1450 /// A regular string, like `"foo"`.
1452 /// A raw string, like `r##"foo"##`.
1454 /// The value is the number of `#` symbols used.
1459 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
1461 /// The original literal token as written in source code.
1462 pub token: token::Lit,
1463 /// The "semantic" representation of the literal lowered from the original tokens.
1464 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1465 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1470 /// Same as `Lit`, but restricted to string literals.
1471 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)]
1473 /// The original literal token as written in source code.
1474 pub style: StrStyle,
1476 pub suffix: Option<Symbol>,
1478 /// The unescaped "semantic" representation of the literal lowered from the original token.
1479 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1480 pub symbol_unescaped: Symbol,
1484 pub fn as_lit(&self) -> Lit {
1485 let token_kind = match self.style {
1486 StrStyle::Cooked => token::Str,
1487 StrStyle::Raw(n) => token::StrRaw(n),
1490 token: token::Lit::new(token_kind, self.symbol, self.suffix),
1492 kind: LitKind::Str(self.symbol_unescaped, self.style),
1497 /// Type of the integer literal based on provided suffix.
1498 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, Eq, PartialEq)]
1499 #[derive(HashStable_Generic)]
1500 pub enum LitIntType {
1509 /// Type of the float literal based on provided suffix.
1510 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, Eq, PartialEq)]
1511 #[derive(HashStable_Generic)]
1512 pub enum LitFloatType {
1513 /// A float literal with a suffix (`1f32` or `1E10f32`).
1515 /// A float literal without a suffix (`1.0 or 1.0E10`).
1521 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
1522 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
1524 /// A string literal (`"foo"`).
1525 Str(Symbol, StrStyle),
1526 /// A byte string (`b"foo"`).
1527 ByteStr(Lrc<Vec<u8>>),
1528 /// A byte char (`b'f'`).
1530 /// A character literal (`'a'`).
1532 /// An integer literal (`1`).
1533 Int(u128, LitIntType),
1534 /// A float literal (`1f64` or `1E10f64`).
1535 Float(Symbol, LitFloatType),
1536 /// A boolean literal.
1538 /// Placeholder for a literal that wasn't well-formed in some way.
1543 /// Returns `true` if this literal is a string.
1544 pub fn is_str(&self) -> bool {
1546 LitKind::Str(..) => true,
1551 /// Returns `true` if this literal is byte literal string.
1552 pub fn is_bytestr(&self) -> bool {
1554 LitKind::ByteStr(_) => true,
1559 /// Returns `true` if this is a numeric literal.
1560 pub fn is_numeric(&self) -> bool {
1562 LitKind::Int(..) | LitKind::Float(..) => true,
1567 /// Returns `true` if this literal has no suffix.
1568 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1569 pub fn is_unsuffixed(&self) -> bool {
1573 /// Returns `true` if this literal has a suffix.
1574 pub fn is_suffixed(&self) -> bool {
1576 // suffixed variants
1577 LitKind::Int(_, LitIntType::Signed(..))
1578 | LitKind::Int(_, LitIntType::Unsigned(..))
1579 | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
1580 // unsuffixed variants
1582 | LitKind::ByteStr(..)
1585 | LitKind::Int(_, LitIntType::Unsuffixed)
1586 | LitKind::Float(_, LitFloatType::Unsuffixed)
1588 | LitKind::Err(..) => false,
1593 // N.B., If you change this, you'll probably want to change the corresponding
1594 // type structure in `middle/ty.rs` as well.
1595 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1598 pub mutbl: Mutability,
1601 /// Represents a function's signature in a trait declaration,
1602 /// trait implementation, or free function.
1603 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1605 pub header: FnHeader,
1606 pub decl: P<FnDecl>,
1609 /// Represents associated items.
1610 /// These include items in `impl` and `trait` definitions.
1611 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1612 pub struct AssocItem {
1613 pub attrs: Vec<Attribute>,
1616 pub vis: Visibility,
1619 pub defaultness: Defaultness,
1620 pub generics: Generics,
1621 pub kind: AssocItemKind,
1622 /// See `Item::tokens` for what this is.
1623 pub tokens: Option<TokenStream>,
1626 /// Represents various kinds of content within an `impl`.
1628 /// The term "provided" in the variants below refers to the item having a default
1629 /// definition / body. Meanwhile, a "required" item lacks a definition / body.
1630 /// In an implementation, all items must be provided.
1631 /// The `Option`s below denote the bodies, where `Some(_)`
1632 /// means "provided" and conversely `None` means "required".
1633 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1634 pub enum AssocItemKind {
1635 /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
1636 /// If `def` is parsed, then the associated constant is provided, and otherwise required.
1637 Const(P<Ty>, Option<P<Expr>>),
1639 /// An associated function.
1640 Fn(FnSig, Option<P<Block>>),
1642 /// An associated type.
1643 TyAlias(GenericBounds, Option<P<Ty>>),
1645 /// A macro expanding to an associated item.
1668 pub fn name_str(self) -> &'static str {
1670 FloatTy::F32 => "f32",
1671 FloatTy::F64 => "f64",
1675 pub fn name(self) -> Symbol {
1677 FloatTy::F32 => sym::f32,
1678 FloatTy::F64 => sym::f64,
1682 pub fn bit_width(self) -> usize {
1713 pub fn name_str(&self) -> &'static str {
1715 IntTy::Isize => "isize",
1717 IntTy::I16 => "i16",
1718 IntTy::I32 => "i32",
1719 IntTy::I64 => "i64",
1720 IntTy::I128 => "i128",
1724 pub fn name(&self) -> Symbol {
1726 IntTy::Isize => sym::isize,
1727 IntTy::I8 => sym::i8,
1728 IntTy::I16 => sym::i16,
1729 IntTy::I32 => sym::i32,
1730 IntTy::I64 => sym::i64,
1731 IntTy::I128 => sym::i128,
1735 pub fn val_to_string(&self, val: i128) -> String {
1736 // Cast to a `u128` so we can correctly print `INT128_MIN`. All integral types
1737 // are parsed as `u128`, so we wouldn't want to print an extra negative
1739 format!("{}{}", val as u128, self.name_str())
1742 pub fn bit_width(&self) -> Option<usize> {
1744 IntTy::Isize => return None,
1753 pub fn normalize(&self, target_width: u32) -> Self {
1755 IntTy::Isize => match target_width {
1759 _ => unreachable!(),
1789 pub fn name_str(&self) -> &'static str {
1791 UintTy::Usize => "usize",
1793 UintTy::U16 => "u16",
1794 UintTy::U32 => "u32",
1795 UintTy::U64 => "u64",
1796 UintTy::U128 => "u128",
1800 pub fn name(&self) -> Symbol {
1802 UintTy::Usize => sym::usize,
1803 UintTy::U8 => sym::u8,
1804 UintTy::U16 => sym::u16,
1805 UintTy::U32 => sym::u32,
1806 UintTy::U64 => sym::u64,
1807 UintTy::U128 => sym::u128,
1811 pub fn val_to_string(&self, val: u128) -> String {
1812 format!("{}{}", val, self.name_str())
1815 pub fn bit_width(&self) -> Option<usize> {
1817 UintTy::Usize => return None,
1822 UintTy::U128 => 128,
1826 pub fn normalize(&self, target_width: u32) -> Self {
1828 UintTy::Usize => match target_width {
1832 _ => unreachable!(),
1839 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1840 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1841 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1842 pub struct AssocTyConstraint {
1845 pub kind: AssocTyConstraintKind,
1849 /// The kinds of an `AssocTyConstraint`.
1850 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1851 pub enum AssocTyConstraintKind {
1852 /// E.g., `A = Bar` in `Foo<A = Bar>`.
1853 Equality { ty: P<Ty> },
1854 /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
1855 Bound { bounds: GenericBounds },
1858 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1865 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1866 pub struct BareFnTy {
1867 pub unsafety: Unsafe,
1869 pub generic_params: Vec<GenericParam>,
1870 pub decl: P<FnDecl>,
1873 /// The various kinds of type recognized by the compiler.
1874 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1876 /// A variable-length slice (`[T]`).
1878 /// A fixed length array (`[T; n]`).
1879 Array(P<Ty>, AnonConst),
1880 /// A raw pointer (`*const T` or `*mut T`).
1882 /// A reference (`&'a T` or `&'a mut T`).
1883 Rptr(Option<Lifetime>, MutTy),
1884 /// A bare function (e.g., `fn(usize) -> bool`).
1885 BareFn(P<BareFnTy>),
1886 /// The never type (`!`).
1888 /// A tuple (`(A, B, C, D,...)`).
1890 /// A path (`module::module::...::Type`), optionally
1891 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
1893 /// Type parameters are stored in the `Path` itself.
1894 Path(Option<QSelf>, Path),
1895 /// A trait object type `Bound1 + Bound2 + Bound3`
1896 /// where `Bound` is a trait or a lifetime.
1897 TraitObject(GenericBounds, TraitObjectSyntax),
1898 /// An `impl Bound1 + Bound2 + Bound3` type
1899 /// where `Bound` is a trait or a lifetime.
1901 /// The `NodeId` exists to prevent lowering from having to
1902 /// generate `NodeId`s on the fly, which would complicate
1903 /// the generation of opaque `type Foo = impl Trait` items significantly.
1904 ImplTrait(NodeId, GenericBounds),
1905 /// No-op; kept solely so that we can pretty-print faithfully.
1909 /// This means the type should be inferred instead of it having been
1910 /// specified. This can appear anywhere in a type.
1912 /// Inferred type of a `self` or `&self` argument in a method.
1914 /// A macro in the type position.
1916 /// Placeholder for a kind that has failed to be defined.
1918 /// Placeholder for a `va_list`.
1923 pub fn is_implicit_self(&self) -> bool {
1924 if let TyKind::ImplicitSelf = *self { true } else { false }
1927 pub fn is_unit(&self) -> bool {
1928 if let TyKind::Tup(ref tys) = *self { tys.is_empty() } else { false }
1931 /// HACK(type_alias_impl_trait, Centril): A temporary crutch used
1932 /// in lowering to avoid making larger changes there and beyond.
1933 pub fn opaque_top_hack(&self) -> Option<&GenericBounds> {
1935 Self::ImplTrait(_, bounds) => Some(bounds),
1941 /// Syntax used to declare a trait object.
1942 #[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1943 pub enum TraitObjectSyntax {
1948 /// Inline assembly dialect.
1950 /// E.g., `"intel"` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
1951 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy, HashStable_Generic)]
1952 pub enum AsmDialect {
1957 /// Inline assembly.
1959 /// E.g., `"={eax}"(result)` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
1960 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1961 pub struct InlineAsmOutput {
1962 pub constraint: Symbol,
1965 pub is_indirect: bool,
1968 /// Inline assembly.
1970 /// E.g., `asm!("NOP");`.
1971 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1972 pub struct InlineAsm {
1974 pub asm_str_style: StrStyle,
1975 pub outputs: Vec<InlineAsmOutput>,
1976 pub inputs: Vec<(Symbol, P<Expr>)>,
1977 pub clobbers: Vec<Symbol>,
1979 pub alignstack: bool,
1980 pub dialect: AsmDialect,
1983 /// A parameter in a function header.
1985 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
1986 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1993 pub is_placeholder: bool,
1996 /// Alternative representation for `Arg`s describing `self` parameter of methods.
1998 /// E.g., `&mut self` as in `fn foo(&mut self)`.
1999 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2001 /// `self`, `mut self`
2003 /// `&'lt self`, `&'lt mut self`
2004 Region(Option<Lifetime>, Mutability),
2005 /// `self: TYPE`, `mut self: TYPE`
2006 Explicit(P<Ty>, Mutability),
2009 pub type ExplicitSelf = Spanned<SelfKind>;
2012 /// Attempts to cast parameter to `ExplicitSelf`.
2013 pub fn to_self(&self) -> Option<ExplicitSelf> {
2014 if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
2015 if ident.name == kw::SelfLower {
2016 return match self.ty.kind {
2017 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
2018 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
2019 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
2022 self.pat.span.to(self.ty.span),
2023 SelfKind::Explicit(self.ty.clone(), mutbl),
2031 /// Returns `true` if parameter is `self`.
2032 pub fn is_self(&self) -> bool {
2033 if let PatKind::Ident(_, ident, _) = self.pat.kind {
2034 ident.name == kw::SelfLower
2040 /// Builds a `Param` object from `ExplicitSelf`.
2041 pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
2042 let span = eself.span.to(eself_ident.span);
2043 let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span });
2044 let param = |mutbl, ty| Param {
2048 kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
2054 is_placeholder: false,
2057 SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
2058 SelfKind::Value(mutbl) => param(mutbl, infer_ty),
2059 SelfKind::Region(lt, mutbl) => param(
2063 kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
2071 /// A signature (not the body) of a function declaration.
2073 /// E.g., `fn foo(bar: baz)`.
2075 /// Please note that it's different from `FnHeader` structure
2076 /// which contains metadata about function safety, asyncness, constness and ABI.
2077 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2079 pub inputs: Vec<Param>,
2080 pub output: FunctionRetTy,
2084 pub fn get_self(&self) -> Option<ExplicitSelf> {
2085 self.inputs.get(0).and_then(Param::to_self)
2087 pub fn has_self(&self) -> bool {
2088 self.inputs.get(0).map_or(false, Param::is_self)
2090 pub fn c_variadic(&self) -> bool {
2091 self.inputs.last().map_or(false, |arg| match arg.ty.kind {
2092 TyKind::CVarArgs => true,
2098 /// Is the trait definition an auto trait?
2099 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
2105 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug)]
2106 #[derive(HashStable_Generic)]
2112 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
2114 Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
2119 pub fn is_async(self) -> bool {
2120 if let Async::Yes { .. } = self { true } else { false }
2123 /// In ths case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
2124 pub fn opt_return_id(self) -> Option<NodeId> {
2126 Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
2132 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug)]
2133 #[derive(HashStable_Generic)]
2139 /// Item defaultness.
2140 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
2141 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
2142 pub enum Defaultness {
2147 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable_Generic)]
2148 pub enum ImplPolarity {
2149 /// `impl Trait for Type`
2151 /// `impl !Trait for Type`
2155 impl fmt::Debug for ImplPolarity {
2156 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2158 ImplPolarity::Positive => "positive".fmt(f),
2159 ImplPolarity::Negative => "negative".fmt(f),
2164 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2165 pub enum FunctionRetTy {
2166 // FIXME(Centril): Rename to `FnRetTy` and in HIR also.
2167 /// Returns type is not specified.
2169 /// Functions default to `()` and closures default to inference.
2170 /// Span points to where return type would be inserted.
2172 /// Everything else.
2176 impl FunctionRetTy {
2177 pub fn span(&self) -> Span {
2179 FunctionRetTy::Default(span) => span,
2180 FunctionRetTy::Ty(ref ty) => ty.span,
2185 /// Module declaration.
2187 /// E.g., `mod foo;` or `mod foo { .. }`.
2188 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2190 /// A span from the first token past `{` to the last token until `}`.
2191 /// For `mod foo;`, the inner span ranges from the first token
2192 /// to the last token in the external file.
2194 pub items: Vec<P<Item>>,
2195 /// `true` for `mod foo { .. }`; `false` for `mod foo;`.
2199 /// Foreign module declaration.
2201 /// E.g., `extern { .. }` or `extern C { .. }`.
2202 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2203 pub struct ForeignMod {
2204 pub abi: Option<StrLit>,
2205 pub items: Vec<P<ForeignItem>>,
2208 /// Global inline assembly.
2210 /// Also known as "module-level assembly" or "file-scoped assembly".
2211 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
2212 pub struct GlobalAsm {
2216 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2217 pub struct EnumDef {
2218 pub variants: Vec<Variant>,
2221 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2222 pub struct Variant {
2223 /// Attributes of the variant.
2224 pub attrs: Vec<Attribute>,
2225 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2229 /// The visibility of the variant. Syntactically accepted but not semantically.
2230 pub vis: Visibility,
2231 /// Name of the variant.
2234 /// Fields and constructor id of the variant.
2235 pub data: VariantData,
2236 /// Explicit discriminant, e.g., `Foo = 1`.
2237 pub disr_expr: Option<AnonConst>,
2238 /// Is a macro placeholder
2239 pub is_placeholder: bool,
2242 /// Part of `use` item to the right of its prefix.
2243 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2244 pub enum UseTreeKind {
2245 /// `use prefix` or `use prefix as rename`
2247 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2249 Simple(Option<Ident>, NodeId, NodeId),
2250 /// `use prefix::{...}`
2251 Nested(Vec<(UseTree, NodeId)>),
2256 /// A tree of paths sharing common prefixes.
2257 /// Used in `use` items both at top-level and inside of braces in import groups.
2258 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2259 pub struct UseTree {
2261 pub kind: UseTreeKind,
2266 pub fn ident(&self) -> Ident {
2268 UseTreeKind::Simple(Some(rename), ..) => rename,
2269 UseTreeKind::Simple(None, ..) => {
2270 self.prefix.segments.last().expect("empty prefix in a simple import").ident
2272 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2277 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2278 /// are contained as statements within items. These two cases need to be
2279 /// distinguished for pretty-printing.
2280 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy, HashStable_Generic)]
2281 pub enum AttrStyle {
2286 #[derive(Clone, PartialEq, Eq, Hash, Debug, PartialOrd, Ord, Copy)]
2287 pub struct AttrId(pub usize);
2289 impl Idx for AttrId {
2290 fn new(idx: usize) -> Self {
2293 fn index(self) -> usize {
2298 impl rustc_serialize::Encodable for AttrId {
2299 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
2304 impl rustc_serialize::Decodable for AttrId {
2305 fn decode<D: Decoder>(d: &mut D) -> Result<AttrId, D::Error> {
2306 d.read_nil().map(|_| crate::attr::mk_attr_id())
2310 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
2311 pub struct AttrItem {
2316 /// A list of attributes.
2317 pub type AttrVec = ThinVec<Attribute>;
2319 /// Metadata associated with an item.
2320 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2321 pub struct Attribute {
2324 /// Denotes if the attribute decorates the following construct (outer)
2325 /// or the construct this attribute is contained within (inner).
2326 pub style: AttrStyle,
2330 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2332 /// A normal attribute.
2335 /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
2336 /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
2337 /// variant (which is much less compact and thus more expensive).
2341 /// `TraitRef`s appear in impls.
2343 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2344 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2345 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2346 /// same as the impl's `NodeId`).
2347 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2348 pub struct TraitRef {
2353 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2354 pub struct PolyTraitRef {
2355 /// The `'a` in `<'a> Foo<&'a T>`.
2356 pub bound_generic_params: Vec<GenericParam>,
2358 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2359 pub trait_ref: TraitRef,
2365 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2367 bound_generic_params: generic_params,
2368 trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
2374 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
2375 pub enum CrateSugar {
2376 /// Source is `pub(crate)`.
2379 /// Source is (just) `crate`.
2383 pub type Visibility = Spanned<VisibilityKind>;
2385 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2386 pub enum VisibilityKind {
2389 Restricted { path: P<Path>, id: NodeId },
2393 impl VisibilityKind {
2394 pub fn is_pub(&self) -> bool {
2395 if let VisibilityKind::Public = *self { true } else { false }
2399 /// Field of a struct.
2401 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2402 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2403 pub struct StructField {
2404 pub attrs: Vec<Attribute>,
2407 pub vis: Visibility,
2408 pub ident: Option<Ident>,
2411 pub is_placeholder: bool,
2414 /// Fields and constructor ids of enum variants and structs.
2415 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2416 pub enum VariantData {
2419 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2420 Struct(Vec<StructField>, bool),
2423 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2424 Tuple(Vec<StructField>, NodeId),
2427 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2432 /// Return the fields of this variant.
2433 pub fn fields(&self) -> &[StructField] {
2435 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
2440 /// Return the `NodeId` of this variant's constructor, if it has one.
2441 pub fn ctor_id(&self) -> Option<NodeId> {
2443 VariantData::Struct(..) => None,
2444 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2451 /// The name might be a dummy name in case of anonymous items.
2452 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2453 pub struct Item<K = ItemKind> {
2454 pub attrs: Vec<Attribute>,
2457 pub vis: Visibility,
2462 /// Original tokens this item was parsed from. This isn't necessarily
2463 /// available for all items, although over time more and more items should
2464 /// have this be `Some`. Right now this is primarily used for procedural
2465 /// macros, notably custom attributes.
2467 /// Note that the tokens here do not include the outer attributes, but will
2468 /// include inner attributes.
2469 pub tokens: Option<TokenStream>,
2473 /// Return the span that encompasses the attributes.
2474 pub fn span_with_attributes(&self) -> Span {
2475 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2479 /// `extern` qualifier on a function item or function type.
2480 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)]
2488 pub fn from_abi(abi: Option<StrLit>) -> Extern {
2489 abi.map_or(Extern::Implicit, Extern::Explicit)
2493 /// A function header.
2495 /// All the information between the visibility and the name of the function is
2496 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2497 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)]
2498 pub struct FnHeader {
2499 pub unsafety: Unsafe,
2500 pub asyncness: Async,
2501 pub constness: Const,
2506 /// Does this function header have any qualifiers or is it empty?
2507 pub fn has_qualifiers(&self) -> bool {
2508 let Self { unsafety, asyncness, constness, ext } = self;
2509 matches!(unsafety, Unsafe::Yes(_))
2510 || asyncness.is_async()
2511 || matches!(constness, Const::Yes(_))
2512 || !matches!(ext, Extern::None)
2516 impl Default for FnHeader {
2517 fn default() -> FnHeader {
2519 unsafety: Unsafe::No,
2520 asyncness: Async::No,
2521 constness: Const::No,
2527 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2529 /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
2531 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2532 ExternCrate(Option<Name>),
2533 /// A use declaration item (`use`).
2535 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2537 /// A static item (`static`).
2539 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2540 Static(P<Ty>, Mutability, P<Expr>),
2541 /// A constant item (`const`).
2543 /// E.g., `const FOO: i32 = 42;`.
2544 Const(P<Ty>, P<Expr>),
2545 /// A function declaration (`fn`).
2547 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2548 Fn(FnSig, Generics, Option<P<Block>>),
2549 /// A module declaration (`mod`).
2551 /// E.g., `mod foo;` or `mod foo { .. }`.
2553 /// An external module (`extern`).
2555 /// E.g., `extern {}` or `extern "C" {}`.
2556 ForeignMod(ForeignMod),
2557 /// Module-level inline assembly (from `global_asm!()`).
2558 GlobalAsm(P<GlobalAsm>),
2559 /// A type alias (`type`).
2561 /// E.g., `type Foo = Bar<u8>;`.
2562 TyAlias(P<Ty>, Generics),
2563 /// An enum definition (`enum`).
2565 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2566 Enum(EnumDef, Generics),
2567 /// A struct definition (`struct`).
2569 /// E.g., `struct Foo<A> { x: A }`.
2570 Struct(VariantData, Generics),
2571 /// A union definition (`union`).
2573 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2574 Union(VariantData, Generics),
2575 /// A trait declaration (`trait`).
2577 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2578 Trait(IsAuto, Unsafe, Generics, GenericBounds, Vec<P<AssocItem>>),
2581 /// E.g., `trait Foo = Bar + Quux;`.
2582 TraitAlias(Generics, GenericBounds),
2583 /// An implementation.
2585 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2588 polarity: ImplPolarity,
2589 defaultness: Defaultness,
2593 /// The trait being implemented, if any.
2594 of_trait: Option<TraitRef>,
2597 items: Vec<P<AssocItem>>,
2599 /// A macro invocation.
2601 /// E.g., `foo!(..)`.
2604 /// A macro definition.
2609 pub fn descriptive_variant(&self) -> &str {
2611 ItemKind::ExternCrate(..) => "extern crate",
2612 ItemKind::Use(..) => "use",
2613 ItemKind::Static(..) => "static item",
2614 ItemKind::Const(..) => "constant item",
2615 ItemKind::Fn(..) => "function",
2616 ItemKind::Mod(..) => "module",
2617 ItemKind::ForeignMod(..) => "foreign module",
2618 ItemKind::GlobalAsm(..) => "global asm",
2619 ItemKind::TyAlias(..) => "type alias",
2620 ItemKind::Enum(..) => "enum",
2621 ItemKind::Struct(..) => "struct",
2622 ItemKind::Union(..) => "union",
2623 ItemKind::Trait(..) => "trait",
2624 ItemKind::TraitAlias(..) => "trait alias",
2625 ItemKind::Mac(..) | ItemKind::MacroDef(..) | ItemKind::Impl { .. } => "item",
2629 pub fn generics(&self) -> Option<&Generics> {
2631 Self::Fn(_, generics, _)
2632 | Self::TyAlias(_, generics)
2633 | Self::Enum(_, generics)
2634 | Self::Struct(_, generics)
2635 | Self::Union(_, generics)
2636 | Self::Trait(_, _, generics, ..)
2637 | Self::TraitAlias(generics, _)
2638 | Self::Impl { generics, .. } => Some(generics),
2644 pub type ForeignItem = Item<ForeignItemKind>;
2646 /// An item within an `extern` block.
2647 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2648 pub enum ForeignItemKind {
2649 /// A foreign function.
2650 Fn(FnSig, Generics, Option<P<Block>>),
2651 /// A foreign static item (`static ext: u8`).
2652 Static(P<Ty>, Mutability),
2655 /// A macro invocation.
2659 impl ForeignItemKind {
2660 pub fn descriptive_variant(&self) -> &str {
2662 ForeignItemKind::Fn(..) => "foreign function",
2663 ForeignItemKind::Static(..) => "foreign static item",
2664 ForeignItemKind::Ty => "foreign type",
2665 ForeignItemKind::Macro(..) => "macro in foreign module",