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 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`], [`MacCall`], [`MacDelimiter`]: Macro definition and invocation.
18 //! - [`Attribute`]: Metadata associated with item.
19 //! - [`UnOp`], [`BinOp`], and [`BinOpKind`]: Unary and binary operators.
21 pub use crate::util::parser::ExprPrecedence;
22 pub use GenericArgs::*;
23 pub use UnsafeSource::*;
26 use crate::token::{self, CommentKind, DelimToken, Token};
27 use crate::tokenstream::{DelimSpan, LazyTokenStream, TokenStream, TokenTree};
29 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
30 use rustc_data_structures::stack::ensure_sufficient_stack;
31 use rustc_data_structures::sync::Lrc;
32 use rustc_data_structures::thin_vec::ThinVec;
33 use rustc_macros::HashStable_Generic;
34 use rustc_serialize::{self, Decoder, Encoder};
35 use rustc_span::source_map::{respan, Spanned};
36 use rustc_span::symbol::{kw, sym, Ident, Symbol};
37 use rustc_span::{Span, DUMMY_SP};
39 use std::cmp::Ordering;
40 use std::convert::TryFrom;
46 /// A "Label" is an identifier of some point in sources,
47 /// e.g. in the following code:
55 /// `'outer` is a label.
56 #[derive(Clone, Encodable, Decodable, Copy, HashStable_Generic)]
61 impl fmt::Debug for Label {
62 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
63 write!(f, "label({:?})", self.ident)
67 /// A "Lifetime" is an annotation of the scope in which variable
68 /// can be used, e.g. `'a` in `&'a i32`.
69 #[derive(Clone, Encodable, Decodable, Copy)]
75 impl fmt::Debug for Lifetime {
76 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
77 write!(f, "lifetime({}: {})", self.id, self)
81 impl fmt::Display for Lifetime {
82 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
83 write!(f, "{}", self.ident.name)
87 /// A "Path" is essentially Rust's notion of a name.
89 /// It's represented as a sequence of identifiers,
90 /// along with a bunch of supporting information.
92 /// E.g., `std::cmp::PartialEq`.
93 #[derive(Clone, Encodable, Decodable, Debug)]
96 /// The segments in the path: the things separated by `::`.
97 /// Global paths begin with `kw::PathRoot`.
98 pub segments: Vec<PathSegment>,
99 pub tokens: Option<LazyTokenStream>,
102 impl PartialEq<Symbol> for Path {
104 fn eq(&self, symbol: &Symbol) -> bool {
105 self.segments.len() == 1 && { self.segments[0].ident.name == *symbol }
109 impl<CTX> HashStable<CTX> for Path {
110 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
111 self.segments.len().hash_stable(hcx, hasher);
112 for segment in &self.segments {
113 segment.ident.name.hash_stable(hcx, hasher);
119 // Convert a span and an identifier to the corresponding
121 pub fn from_ident(ident: Ident) -> Path {
122 Path { segments: vec![PathSegment::from_ident(ident)], span: ident.span, tokens: None }
125 pub fn is_global(&self) -> bool {
126 !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
130 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
132 /// E.g., `std`, `String` or `Box<T>`.
133 #[derive(Clone, Encodable, Decodable, Debug)]
134 pub struct PathSegment {
135 /// The identifier portion of this path segment.
140 /// Type/lifetime parameters attached to this path. They come in
141 /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
142 /// `None` means that no parameter list is supplied (`Path`),
143 /// `Some` means that parameter list is supplied (`Path<X, Y>`)
144 /// but it can be empty (`Path<>`).
145 /// `P` is used as a size optimization for the common case with no parameters.
146 pub args: Option<P<GenericArgs>>,
150 pub fn from_ident(ident: Ident) -> Self {
151 PathSegment { ident, id: DUMMY_NODE_ID, args: None }
154 pub fn path_root(span: Span) -> Self {
155 PathSegment::from_ident(Ident::new(kw::PathRoot, span))
158 pub fn span(&self) -> Span {
160 Some(args) => self.ident.span.to(args.span()),
161 None => self.ident.span,
166 /// The arguments of a path segment.
168 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
169 #[derive(Clone, Encodable, Decodable, Debug)]
170 pub enum GenericArgs {
171 /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
172 AngleBracketed(AngleBracketedArgs),
173 /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
174 Parenthesized(ParenthesizedArgs),
178 pub fn is_angle_bracketed(&self) -> bool {
179 matches!(self, AngleBracketed(..))
182 pub fn span(&self) -> Span {
184 AngleBracketed(ref data) => data.span,
185 Parenthesized(ref data) => data.span,
190 /// Concrete argument in the sequence of generic args.
191 #[derive(Clone, Encodable, Decodable, Debug)]
192 pub enum GenericArg {
193 /// `'a` in `Foo<'a>`
195 /// `Bar` in `Foo<Bar>`
202 pub fn span(&self) -> Span {
204 GenericArg::Lifetime(lt) => lt.ident.span,
205 GenericArg::Type(ty) => ty.span,
206 GenericArg::Const(ct) => ct.value.span,
211 /// A path like `Foo<'a, T>`.
212 #[derive(Clone, Encodable, Decodable, Debug, Default)]
213 pub struct AngleBracketedArgs {
214 /// The overall span.
216 /// The comma separated parts in the `<...>`.
217 pub args: Vec<AngleBracketedArg>,
220 /// Either an argument for a parameter e.g., `'a`, `Vec<u8>`, `0`,
221 /// or a constraint on an associated item, e.g., `Item = String` or `Item: Bound`.
222 #[derive(Clone, Encodable, Decodable, Debug)]
223 pub enum AngleBracketedArg {
224 /// Argument for a generic parameter.
226 /// Constraint for an associated item.
227 Constraint(AssocTyConstraint),
230 impl AngleBracketedArg {
231 pub fn span(&self) -> Span {
233 AngleBracketedArg::Arg(arg) => arg.span(),
234 AngleBracketedArg::Constraint(constraint) => constraint.span,
239 impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
240 fn into(self) -> Option<P<GenericArgs>> {
241 Some(P(GenericArgs::AngleBracketed(self)))
245 impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
246 fn into(self) -> Option<P<GenericArgs>> {
247 Some(P(GenericArgs::Parenthesized(self)))
251 /// A path like `Foo(A, B) -> C`.
252 #[derive(Clone, Encodable, Decodable, Debug)]
253 pub struct ParenthesizedArgs {
261 pub inputs: Vec<P<Ty>>,
267 pub inputs_span: Span,
273 impl ParenthesizedArgs {
274 pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
279 .map(|input| AngleBracketedArg::Arg(GenericArg::Type(input)))
281 AngleBracketedArgs { span: self.inputs_span, args }
285 pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
287 /// A modifier on a bound, e.g., `?Sized` or `~const Trait`.
289 /// Negative bounds should also be handled here.
290 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
291 pub enum TraitBoundModifier {
303 // This parses but will be rejected during AST validation.
307 /// The AST represents all type param bounds as types.
308 /// `typeck::collect::compute_bounds` matches these against
309 /// the "special" built-in traits (see `middle::lang_items`) and
310 /// detects `Copy`, `Send` and `Sync`.
311 #[derive(Clone, Encodable, Decodable, Debug)]
312 pub enum GenericBound {
313 Trait(PolyTraitRef, TraitBoundModifier),
318 pub fn span(&self) -> Span {
320 GenericBound::Trait(ref t, ..) => t.span,
321 GenericBound::Outlives(ref l) => l.ident.span,
326 pub type GenericBounds = Vec<GenericBound>;
328 /// Specifies the enforced ordering for generic parameters. In the future,
329 /// if we wanted to relax this order, we could override `PartialEq` and
330 /// `PartialOrd`, to allow the kinds to be unordered.
331 #[derive(Hash, Clone, Copy)]
332 pub enum ParamKindOrd {
335 // `unordered` is only `true` if `sess.unordered_const_ty_params()`
336 // returns true. Specifically, if it's only `min_const_generics`, it will still require
337 // ordering consts after types.
338 Const { unordered: bool },
339 // `Infer` is not actually constructed directly from the AST, but is implicitly constructed
340 // during HIR lowering, and `ParamKindOrd` will implicitly order inferred variables last.
344 impl Ord for ParamKindOrd {
345 fn cmp(&self, other: &Self) -> Ordering {
347 let to_int = |v| match v {
349 Infer | Type | Const { unordered: true } => 1,
350 // technically both consts should be ordered equally,
351 // but only one is ever encountered at a time, so this is
353 Const { unordered: false } => 2,
356 to_int(*self).cmp(&to_int(*other))
359 impl PartialOrd for ParamKindOrd {
360 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
361 Some(self.cmp(other))
364 impl PartialEq for ParamKindOrd {
365 fn eq(&self, other: &Self) -> bool {
366 self.cmp(other) == Ordering::Equal
369 impl Eq for ParamKindOrd {}
371 impl fmt::Display for ParamKindOrd {
372 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
374 ParamKindOrd::Lifetime => "lifetime".fmt(f),
375 ParamKindOrd::Type => "type".fmt(f),
376 ParamKindOrd::Const { .. } => "const".fmt(f),
377 ParamKindOrd::Infer => "infer".fmt(f),
382 #[derive(Clone, Encodable, Decodable, Debug)]
383 pub enum GenericParamKind {
384 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
387 default: Option<P<Ty>>,
391 /// Span of the `const` keyword.
393 /// Optional default value for the const generic param
394 default: Option<AnonConst>,
398 #[derive(Clone, Encodable, Decodable, Debug)]
399 pub struct GenericParam {
403 pub bounds: GenericBounds,
404 pub is_placeholder: bool,
405 pub kind: GenericParamKind,
408 /// Represents lifetime, type and const parameters attached to a declaration of
409 /// a function, enum, trait, etc.
410 #[derive(Clone, Encodable, Decodable, Debug)]
411 pub struct Generics {
412 pub params: Vec<GenericParam>,
413 pub where_clause: WhereClause,
417 impl Default for Generics {
418 /// Creates an instance of `Generics`.
419 fn default() -> Generics {
422 where_clause: WhereClause {
423 has_where_token: false,
424 predicates: Vec::new(),
432 /// A where-clause in a definition.
433 #[derive(Clone, Encodable, Decodable, Debug)]
434 pub struct WhereClause {
435 /// `true` if we ate a `where` token: this can happen
436 /// if we parsed no predicates (e.g. `struct Foo where {}`).
437 /// This allows us to accurately pretty-print
438 /// in `nt_to_tokenstream`
439 pub has_where_token: bool,
440 pub predicates: Vec<WherePredicate>,
444 /// A single predicate in a where-clause.
445 #[derive(Clone, Encodable, Decodable, Debug)]
446 pub enum WherePredicate {
447 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
448 BoundPredicate(WhereBoundPredicate),
449 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
450 RegionPredicate(WhereRegionPredicate),
451 /// An equality predicate (unsupported).
452 EqPredicate(WhereEqPredicate),
455 impl WherePredicate {
456 pub fn span(&self) -> Span {
458 WherePredicate::BoundPredicate(p) => p.span,
459 WherePredicate::RegionPredicate(p) => p.span,
460 WherePredicate::EqPredicate(p) => p.span,
467 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
468 #[derive(Clone, Encodable, Decodable, Debug)]
469 pub struct WhereBoundPredicate {
471 /// Any generics from a `for` binding.
472 pub bound_generic_params: Vec<GenericParam>,
473 /// The type being bounded.
474 pub bounded_ty: P<Ty>,
475 /// Trait and lifetime bounds (`Clone + Send + 'static`).
476 pub bounds: GenericBounds,
479 /// A lifetime predicate.
481 /// E.g., `'a: 'b + 'c`.
482 #[derive(Clone, Encodable, Decodable, Debug)]
483 pub struct WhereRegionPredicate {
485 pub lifetime: Lifetime,
486 pub bounds: GenericBounds,
489 /// An equality predicate (unsupported).
492 #[derive(Clone, Encodable, Decodable, Debug)]
493 pub struct WhereEqPredicate {
500 #[derive(Clone, Encodable, Decodable, Debug)]
502 pub attrs: Vec<Attribute>,
503 pub items: Vec<P<Item>>,
505 /// The order of items in the HIR is unrelated to the order of
506 /// items in the AST. However, we generate proc macro harnesses
507 /// based on the AST order, and later refer to these harnesses
508 /// from the HIR. This field keeps track of the order in which
509 /// we generated proc macros harnesses, so that we can map
510 /// HIR proc macros items back to their harness items.
511 pub proc_macros: Vec<NodeId>,
514 /// Possible values inside of compile-time attribute lists.
516 /// E.g., the '..' in `#[name(..)]`.
517 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
518 pub enum NestedMetaItem {
519 /// A full MetaItem, for recursive meta items.
523 /// E.g., `"foo"`, `64`, `true`.
527 /// A spanned compile-time attribute item.
529 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
530 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
531 pub struct MetaItem {
533 pub kind: MetaItemKind,
537 /// A compile-time attribute item.
539 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
540 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
541 pub enum MetaItemKind {
544 /// E.g., `test` as in `#[test]`.
548 /// E.g., `derive(..)` as in `#[derive(..)]`.
549 List(Vec<NestedMetaItem>),
550 /// Name value meta item.
552 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
556 /// A block (`{ .. }`).
558 /// E.g., `{ .. }` as in `fn foo() { .. }`.
559 #[derive(Clone, Encodable, Decodable, Debug)]
561 /// The statements in the block.
562 pub stmts: Vec<Stmt>,
564 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
565 pub rules: BlockCheckMode,
567 pub tokens: Option<LazyTokenStream>,
568 /// The following *isn't* a parse error, but will cause multiple errors in following stages.
575 pub could_be_bare_literal: bool,
580 /// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
581 #[derive(Clone, Encodable, Decodable, Debug)]
586 pub tokens: Option<LazyTokenStream>,
590 /// Attempt reparsing the pattern as a type.
591 /// This is intended for use by diagnostics.
592 pub fn to_ty(&self) -> Option<P<Ty>> {
593 let kind = match &self.kind {
594 // In a type expression `_` is an inference variable.
595 PatKind::Wild => TyKind::Infer,
596 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
597 PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
598 TyKind::Path(None, Path::from_ident(*ident))
600 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
601 PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
602 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
603 PatKind::Ref(pat, mutbl) => {
604 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
606 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
607 // when `P` can be reparsed as a type `T`.
608 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
609 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
610 // assuming `T0` to `Tn` are all syntactically valid as types.
611 PatKind::Tuple(pats) => {
612 let mut tys = Vec::with_capacity(pats.len());
613 // FIXME(#48994) - could just be collected into an Option<Vec>
615 tys.push(pat.to_ty()?);
622 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
625 /// Walk top-down and call `it` in each place where a pattern occurs
626 /// starting with the root pattern `walk` is called on. If `it` returns
627 /// false then we will descend no further but siblings will be processed.
628 pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
634 // Walk into the pattern associated with `Ident` (if any).
635 PatKind::Ident(_, _, Some(p)) => p.walk(it),
637 // Walk into each field of struct.
638 PatKind::Struct(_, _, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
640 // Sequence of patterns.
641 PatKind::TupleStruct(_, _, s)
644 | PatKind::Or(s) => s.iter().for_each(|p| p.walk(it)),
646 // Trivial wrappers over inner patterns.
647 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
649 // These patterns do not contain subpatterns, skip.
656 | PatKind::MacCall(_) => {}
660 /// Is this a `..` pattern?
661 pub fn is_rest(&self) -> bool {
662 matches!(self.kind, PatKind::Rest)
666 /// A single field in a struct pattern.
668 /// Patterns like the fields of `Foo { x, ref y, ref mut z }`
669 /// are treated the same as `x: x, y: ref y, z: ref mut z`,
670 /// except when `is_shorthand` is true.
671 #[derive(Clone, Encodable, Decodable, Debug)]
672 pub struct PatField {
673 /// The identifier for the field.
675 /// The pattern the field is destructured to.
677 pub is_shorthand: bool,
681 pub is_placeholder: bool,
684 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
685 pub enum BindingMode {
690 #[derive(Clone, Encodable, Decodable, Debug)]
693 Included(RangeSyntax),
698 #[derive(Clone, Encodable, Decodable, Debug)]
699 pub enum RangeSyntax {
706 /// All the different flavors of pattern that Rust recognizes.
707 #[derive(Clone, Encodable, Decodable, Debug)]
709 /// Represents a wildcard pattern (`_`).
712 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
713 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
714 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
715 /// during name resolution.
716 Ident(BindingMode, Ident, Option<P<Pat>>),
718 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
719 /// The `bool` is `true` in the presence of a `..`.
720 Struct(Option<QSelf>, Path, Vec<PatField>, /* recovered */ bool),
722 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
723 TupleStruct(Option<QSelf>, Path, Vec<P<Pat>>),
725 /// An or-pattern `A | B | C`.
726 /// Invariant: `pats.len() >= 2`.
729 /// A possibly qualified path pattern.
730 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
731 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
732 /// only legally refer to associated constants.
733 Path(Option<QSelf>, Path),
735 /// A tuple pattern (`(a, b)`).
741 /// A reference pattern (e.g., `&mut (a, b)`).
742 Ref(P<Pat>, Mutability),
747 /// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
748 Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
750 /// A slice pattern `[a, b, c]`.
753 /// A rest pattern `..`.
755 /// Syntactically it is valid anywhere.
757 /// Semantically however, it only has meaning immediately inside:
758 /// - a slice pattern: `[a, .., b]`,
759 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
760 /// - a tuple pattern: `(a, .., b)`,
761 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
763 /// In all of these cases, an additional restriction applies,
764 /// only one rest pattern may occur in the pattern sequences.
767 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
770 /// A macro pattern; pre-expansion.
774 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
775 #[derive(HashStable_Generic, Encodable, Decodable)]
776 pub enum Mutability {
782 pub fn invert(self) -> Self {
784 Mutability::Mut => Mutability::Not,
785 Mutability::Not => Mutability::Mut,
789 pub fn prefix_str(&self) -> &'static str {
791 Mutability::Mut => "mut ",
792 Mutability::Not => "",
797 /// The kind of borrow in an `AddrOf` expression,
798 /// e.g., `&place` or `&raw const place`.
799 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
800 #[derive(Encodable, Decodable, HashStable_Generic)]
801 pub enum BorrowKind {
802 /// A normal borrow, `&$expr` or `&mut $expr`.
803 /// The resulting type is either `&'a T` or `&'a mut T`
804 /// where `T = typeof($expr)` and `'a` is some lifetime.
806 /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
807 /// The resulting type is either `*const T` or `*mut T`
808 /// where `T = typeof($expr)`.
812 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
814 /// The `+` operator (addition)
816 /// The `-` operator (subtraction)
818 /// The `*` operator (multiplication)
820 /// The `/` operator (division)
822 /// The `%` operator (modulus)
824 /// The `&&` operator (logical and)
826 /// The `||` operator (logical or)
828 /// The `^` operator (bitwise xor)
830 /// The `&` operator (bitwise and)
832 /// The `|` operator (bitwise or)
834 /// The `<<` operator (shift left)
836 /// The `>>` operator (shift right)
838 /// The `==` operator (equality)
840 /// The `<` operator (less than)
842 /// The `<=` operator (less than or equal to)
844 /// The `!=` operator (not equal to)
846 /// The `>=` operator (greater than or equal to)
848 /// The `>` operator (greater than)
853 pub fn to_string(&self) -> &'static str {
876 pub fn lazy(&self) -> bool {
877 matches!(self, BinOpKind::And | BinOpKind::Or)
880 pub fn is_comparison(&self) -> bool {
882 // Note for developers: please keep this as is;
883 // we want compilation to fail if another variant is added.
885 Eq | Lt | Le | Ne | Gt | Ge => true,
886 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
891 pub type BinOp = Spanned<BinOpKind>;
895 /// Note that `&data` is not an operator, it's an `AddrOf` expression.
896 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
898 /// The `*` operator for dereferencing
900 /// The `!` operator for logical inversion
902 /// The `-` operator for negation
907 pub fn to_string(op: UnOp) -> &'static str {
917 #[derive(Clone, Encodable, Decodable, Debug)]
925 pub fn tokens(&self) -> Option<&LazyTokenStream> {
927 StmtKind::Local(ref local) => local.tokens.as_ref(),
928 StmtKind::Item(ref item) => item.tokens.as_ref(),
929 StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => expr.tokens.as_ref(),
930 StmtKind::Empty => None,
931 StmtKind::MacCall(ref mac) => mac.tokens.as_ref(),
935 pub fn has_trailing_semicolon(&self) -> bool {
937 StmtKind::Semi(_) => true,
938 StmtKind::MacCall(mac) => matches!(mac.style, MacStmtStyle::Semicolon),
943 /// Converts a parsed `Stmt` to a `Stmt` with
944 /// a trailing semicolon.
946 /// This only modifies the parsed AST struct, not the attached
947 /// `LazyTokenStream`. The parser is responsible for calling
948 /// `CreateTokenStream::add_trailing_semi` when there is actually
949 /// a semicolon in the tokenstream.
950 pub fn add_trailing_semicolon(mut self) -> Self {
951 self.kind = match self.kind {
952 StmtKind::Expr(expr) => StmtKind::Semi(expr),
953 StmtKind::MacCall(mac) => {
954 StmtKind::MacCall(mac.map(|MacCallStmt { mac, style: _, attrs, tokens }| {
955 MacCallStmt { mac, style: MacStmtStyle::Semicolon, attrs, tokens }
964 pub fn is_item(&self) -> bool {
965 matches!(self.kind, StmtKind::Item(_))
968 pub fn is_expr(&self) -> bool {
969 matches!(self.kind, StmtKind::Expr(_))
973 #[derive(Clone, Encodable, Decodable, Debug)]
975 /// A local (let) binding.
977 /// An item definition.
979 /// Expr without trailing semi-colon.
981 /// Expr with a trailing semi-colon.
983 /// Just a trailing semi-colon.
986 MacCall(P<MacCallStmt>),
989 #[derive(Clone, Encodable, Decodable, Debug)]
990 pub struct MacCallStmt {
992 pub style: MacStmtStyle,
994 pub tokens: Option<LazyTokenStream>,
997 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
998 pub enum MacStmtStyle {
999 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
1000 /// `foo!(...);`, `foo![...];`).
1002 /// The macro statement had braces (e.g., `foo! { ... }`).
1004 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
1005 /// `foo!(...)`). All of these will end up being converted into macro
1010 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
1011 #[derive(Clone, Encodable, Decodable, Debug)]
1015 pub ty: Option<P<Ty>>,
1016 pub kind: LocalKind,
1019 pub tokens: Option<LazyTokenStream>,
1022 #[derive(Clone, Encodable, Decodable, Debug)]
1023 pub enum LocalKind {
1024 /// Local declaration.
1025 /// Example: `let x;`
1027 /// Local declaration with an initializer.
1028 /// Example: `let x = y;`
1030 /// Local declaration with an initializer and an `else` clause.
1031 /// Example: `let Some(x) = y else { return };`
1032 InitElse(P<Expr>, P<Block>),
1036 pub fn init(&self) -> Option<&Expr> {
1039 Self::Init(i) | Self::InitElse(i, _) => Some(i),
1043 pub fn init_else_opt(&self) -> Option<(&Expr, Option<&Block>)> {
1046 Self::Init(init) => Some((init, None)),
1047 Self::InitElse(init, els) => Some((init, Some(els))),
1052 /// An arm of a 'match'.
1054 /// E.g., `0..=10 => { println!("match!") }` as in
1058 /// 0..=10 => { println!("match!") },
1059 /// _ => { println!("no match!") },
1062 #[derive(Clone, Encodable, Decodable, Debug)]
1065 /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
1067 /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
1068 pub guard: Option<P<Expr>>,
1073 pub is_placeholder: bool,
1076 /// A single field in a struct expression, e.g. `x: value` and `y` in `Foo { x: value, y }`.
1077 #[derive(Clone, Encodable, Decodable, Debug)]
1078 pub struct ExprField {
1084 pub is_shorthand: bool,
1085 pub is_placeholder: bool,
1088 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1089 pub enum BlockCheckMode {
1091 Unsafe(UnsafeSource),
1094 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1095 pub enum UnsafeSource {
1100 /// A constant (expression) that's not an item or associated item,
1101 /// but needs its own `DefId` for type-checking, const-eval, etc.
1102 /// These are usually found nested inside types (e.g., array lengths)
1103 /// or expressions (e.g., repeat counts), and also used to define
1104 /// explicit discriminant values for enum variants.
1105 #[derive(Clone, Encodable, Decodable, Debug)]
1106 pub struct AnonConst {
1112 #[derive(Clone, Encodable, Decodable, Debug)]
1118 pub tokens: Option<LazyTokenStream>,
1121 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
1122 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
1123 rustc_data_structures::static_assert_size!(Expr, 104);
1126 /// Returns `true` if this expression would be valid somewhere that expects a value;
1127 /// for example, an `if` condition.
1128 pub fn returns(&self) -> bool {
1129 if let ExprKind::Block(ref block, _) = self.kind {
1130 match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
1132 Some(StmtKind::Expr(_)) => true,
1133 // Last statement is an explicit return?
1134 Some(StmtKind::Semi(expr)) => matches!(expr.kind, ExprKind::Ret(_)),
1135 // This is a block that doesn't end in either an implicit or explicit return.
1139 // This is not a block, it is a value.
1144 /// Is this expr either `N`, or `{ N }`.
1146 /// If this is not the case, name resolution does not resolve `N` when using
1147 /// `min_const_generics` as more complex expressions are not supported.
1148 pub fn is_potential_trivial_const_param(&self) -> bool {
1149 let this = if let ExprKind::Block(ref block, None) = self.kind {
1150 if block.stmts.len() == 1 {
1151 if let StmtKind::Expr(ref expr) = block.stmts[0].kind { expr } else { self }
1159 if let ExprKind::Path(None, ref path) = this.kind {
1160 if path.segments.len() == 1 && path.segments[0].args.is_none() {
1168 pub fn to_bound(&self) -> Option<GenericBound> {
1170 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1171 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1172 TraitBoundModifier::None,
1178 pub fn peel_parens(&self) -> &Expr {
1179 let mut expr = self;
1180 while let ExprKind::Paren(inner) = &expr.kind {
1186 /// Attempts to reparse as `Ty` (for diagnostic purposes).
1187 pub fn to_ty(&self) -> Option<P<Ty>> {
1188 let kind = match &self.kind {
1189 // Trivial conversions.
1190 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1191 ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
1193 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1195 ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
1196 expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
1199 ExprKind::Repeat(expr, expr_len) => {
1200 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1203 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1205 ExprKind::Tup(exprs) => {
1206 let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
1210 // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
1211 // then type of result is trait object.
1212 // Otherwise we don't assume the result type.
1213 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1214 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1215 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1221 // This expression doesn't look like a type syntactically.
1225 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
1228 pub fn precedence(&self) -> ExprPrecedence {
1230 ExprKind::Box(_) => ExprPrecedence::Box,
1231 ExprKind::Array(_) => ExprPrecedence::Array,
1232 ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
1233 ExprKind::Call(..) => ExprPrecedence::Call,
1234 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1235 ExprKind::Tup(_) => ExprPrecedence::Tup,
1236 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1237 ExprKind::Unary(..) => ExprPrecedence::Unary,
1238 ExprKind::Lit(_) => ExprPrecedence::Lit,
1239 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1240 ExprKind::Let(..) => ExprPrecedence::Let,
1241 ExprKind::If(..) => ExprPrecedence::If,
1242 ExprKind::While(..) => ExprPrecedence::While,
1243 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1244 ExprKind::Loop(..) => ExprPrecedence::Loop,
1245 ExprKind::Match(..) => ExprPrecedence::Match,
1246 ExprKind::Closure(..) => ExprPrecedence::Closure,
1247 ExprKind::Block(..) => ExprPrecedence::Block,
1248 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1249 ExprKind::Async(..) => ExprPrecedence::Async,
1250 ExprKind::Await(..) => ExprPrecedence::Await,
1251 ExprKind::Assign(..) => ExprPrecedence::Assign,
1252 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1253 ExprKind::Field(..) => ExprPrecedence::Field,
1254 ExprKind::Index(..) => ExprPrecedence::Index,
1255 ExprKind::Range(..) => ExprPrecedence::Range,
1256 ExprKind::Underscore => ExprPrecedence::Path,
1257 ExprKind::Path(..) => ExprPrecedence::Path,
1258 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1259 ExprKind::Break(..) => ExprPrecedence::Break,
1260 ExprKind::Continue(..) => ExprPrecedence::Continue,
1261 ExprKind::Ret(..) => ExprPrecedence::Ret,
1262 ExprKind::InlineAsm(..) | ExprKind::LlvmInlineAsm(..) => ExprPrecedence::InlineAsm,
1263 ExprKind::MacCall(..) => ExprPrecedence::Mac,
1264 ExprKind::Struct(..) => ExprPrecedence::Struct,
1265 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1266 ExprKind::Paren(..) => ExprPrecedence::Paren,
1267 ExprKind::Try(..) => ExprPrecedence::Try,
1268 ExprKind::Yield(..) => ExprPrecedence::Yield,
1269 ExprKind::Err => ExprPrecedence::Err,
1274 /// Limit types of a range (inclusive or exclusive)
1275 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
1276 pub enum RangeLimits {
1277 /// Inclusive at the beginning, exclusive at the end
1279 /// Inclusive at the beginning and end
1283 #[derive(Clone, Encodable, Decodable, Debug)]
1284 pub enum StructRest {
1289 /// No trailing `..` or expression.
1293 #[derive(Clone, Encodable, Decodable, Debug)]
1294 pub struct StructExpr {
1295 pub qself: Option<QSelf>,
1297 pub fields: Vec<ExprField>,
1298 pub rest: StructRest,
1301 #[derive(Clone, Encodable, Decodable, Debug)]
1303 /// A `box x` expression.
1305 /// An array (`[a, b, c, d]`)
1306 Array(Vec<P<Expr>>),
1307 /// Allow anonymous constants from an inline `const` block
1308 ConstBlock(AnonConst),
1311 /// The first field resolves to the function itself,
1312 /// and the second field is the list of arguments.
1313 /// This also represents calling the constructor of
1314 /// tuple-like ADTs such as tuple structs and enum variants.
1315 Call(P<Expr>, Vec<P<Expr>>),
1316 /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1318 /// The `PathSegment` represents the method name and its generic arguments
1319 /// (within the angle brackets).
1320 /// The first element of the vector of an `Expr` is the expression that evaluates
1321 /// to the object on which the method is being called on (the receiver),
1322 /// and the remaining elements are the rest of the arguments.
1323 /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1324 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
1325 /// This `Span` is the span of the function, without the dot and receiver
1326 /// (e.g. `foo(a, b)` in `x.foo(a, b)`
1327 MethodCall(PathSegment, Vec<P<Expr>>, Span),
1328 /// A tuple (e.g., `(a, b, c, d)`).
1330 /// A binary operation (e.g., `a + b`, `a * b`).
1331 Binary(BinOp, P<Expr>, P<Expr>),
1332 /// A unary operation (e.g., `!x`, `*x`).
1333 Unary(UnOp, P<Expr>),
1334 /// A literal (e.g., `1`, `"foo"`).
1336 /// A cast (e.g., `foo as f64`).
1337 Cast(P<Expr>, P<Ty>),
1338 /// A type ascription (e.g., `42: usize`).
1339 Type(P<Expr>, P<Ty>),
1340 /// A `let pat = expr` expression that is only semantically allowed in the condition
1341 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1343 /// `Span` represents the whole `let pat = expr` statement.
1344 Let(P<Pat>, P<Expr>, Span),
1345 /// An `if` block, with an optional `else` block.
1347 /// `if expr { block } else { expr }`
1348 If(P<Expr>, P<Block>, Option<P<Expr>>),
1349 /// A while loop, with an optional label.
1351 /// `'label: while expr { block }`
1352 While(P<Expr>, P<Block>, Option<Label>),
1353 /// A `for` loop, with an optional label.
1355 /// `'label: for pat in expr { block }`
1357 /// This is desugared to a combination of `loop` and `match` expressions.
1358 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1359 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1361 /// `'label: loop { block }`
1362 Loop(P<Block>, Option<Label>),
1363 /// A `match` block.
1364 Match(P<Expr>, Vec<Arm>),
1365 /// A closure (e.g., `move |a, b, c| a + b + c`).
1367 /// The final span is the span of the argument block `|...|`.
1368 Closure(CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
1369 /// A block (`'label: { ... }`).
1370 Block(P<Block>, Option<Label>),
1371 /// An async block (`async move { ... }`).
1373 /// The `NodeId` is the `NodeId` for the closure that results from
1374 /// desugaring an async block, just like the NodeId field in the
1375 /// `Async::Yes` variant. This is necessary in order to create a def for the
1376 /// closure which can be used as a parent of any child defs. Defs
1377 /// created during lowering cannot be made the parent of any other
1378 /// preexisting defs.
1379 Async(CaptureBy, NodeId, P<Block>),
1380 /// An await expression (`my_future.await`).
1383 /// A try block (`try { ... }`).
1386 /// An assignment (`a = foo()`).
1387 /// The `Span` argument is the span of the `=` token.
1388 Assign(P<Expr>, P<Expr>, Span),
1389 /// An assignment with an operator.
1392 AssignOp(BinOp, P<Expr>, P<Expr>),
1393 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1394 Field(P<Expr>, Ident),
1395 /// An indexing operation (e.g., `foo[2]`).
1396 Index(P<Expr>, P<Expr>),
1397 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assignment).
1398 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1399 /// An underscore, used in destructuring assignment to ignore a value.
1402 /// Variable reference, possibly containing `::` and/or type
1403 /// parameters (e.g., `foo::bar::<baz>`).
1405 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1406 Path(Option<QSelf>, Path),
1408 /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
1409 AddrOf(BorrowKind, Mutability, P<Expr>),
1410 /// A `break`, with an optional label to break, and an optional expression.
1411 Break(Option<Label>, Option<P<Expr>>),
1412 /// A `continue`, with an optional label.
1413 Continue(Option<Label>),
1414 /// A `return`, with an optional value to be returned.
1415 Ret(Option<P<Expr>>),
1417 /// Output of the `asm!()` macro.
1418 InlineAsm(P<InlineAsm>),
1419 /// Output of the `llvm_asm!()` macro.
1420 LlvmInlineAsm(P<LlvmInlineAsm>),
1422 /// A macro invocation; pre-expansion.
1425 /// A struct literal expression.
1427 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
1428 Struct(P<StructExpr>),
1430 /// An array literal constructed from one repeated element.
1432 /// E.g., `[1; 5]`. The expression is the element to be
1433 /// repeated; the constant is the number of times to repeat it.
1434 Repeat(P<Expr>, AnonConst),
1436 /// No-op: used solely so we can pretty-print faithfully.
1439 /// A try expression (`expr?`).
1442 /// A `yield`, with an optional value to be yielded.
1443 Yield(Option<P<Expr>>),
1445 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1449 /// The explicit `Self` type in a "qualified path". The actual
1450 /// path, including the trait and the associated item, is stored
1451 /// separately. `position` represents the index of the associated
1452 /// item qualified with this `Self` type.
1454 /// ```ignore (only-for-syntax-highlight)
1455 /// <Vec<T> as a::b::Trait>::AssociatedItem
1456 /// ^~~~~ ~~~~~~~~~~~~~~^
1459 /// <Vec<T>>::AssociatedItem
1463 #[derive(Clone, Encodable, Decodable, Debug)]
1467 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1468 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1469 /// 0`, this is an empty span.
1470 pub path_span: Span,
1471 pub position: usize,
1474 /// A capture clause used in closures and `async` blocks.
1475 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1476 pub enum CaptureBy {
1477 /// `move |x| y + x`.
1479 /// `move` keyword was not specified.
1483 /// The movability of a generator / closure literal:
1484 /// whether a generator contains self-references, causing it to be `!Unpin`.
1485 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
1486 #[derive(HashStable_Generic)]
1487 pub enum Movability {
1488 /// May contain self-references, `!Unpin`.
1490 /// Must not contain self-references, `Unpin`.
1494 /// Represents a macro invocation. The `path` indicates which macro
1495 /// is being invoked, and the `args` are arguments passed to it.
1496 #[derive(Clone, Encodable, Decodable, Debug)]
1497 pub struct MacCall {
1499 pub args: P<MacArgs>,
1500 pub prior_type_ascription: Option<(Span, bool)>,
1504 pub fn span(&self) -> Span {
1505 self.path.span.to(self.args.span().unwrap_or(self.path.span))
1509 /// Arguments passed to an attribute or a function-like macro.
1510 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1512 /// No arguments - `#[attr]`.
1514 /// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
1515 Delimited(DelimSpan, MacDelimiter, TokenStream),
1516 /// Arguments of a key-value attribute - `#[attr = "value"]`.
1518 /// Span of the `=` token.
1520 /// "value" as a nonterminal token.
1526 pub fn delim(&self) -> DelimToken {
1528 MacArgs::Delimited(_, delim, _) => delim.to_token(),
1529 MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
1533 pub fn span(&self) -> Option<Span> {
1535 MacArgs::Empty => None,
1536 MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
1537 MacArgs::Eq(eq_span, token) => Some(eq_span.to(token.span)),
1541 /// Tokens inside the delimiters or after `=`.
1542 /// Proc macros see these tokens, for example.
1543 pub fn inner_tokens(&self) -> TokenStream {
1545 MacArgs::Empty => TokenStream::default(),
1546 MacArgs::Delimited(.., tokens) => tokens.clone(),
1547 MacArgs::Eq(.., token) => TokenTree::Token(token.clone()).into(),
1551 /// Whether a macro with these arguments needs a semicolon
1552 /// when used as a standalone item or statement.
1553 pub fn need_semicolon(&self) -> bool {
1554 !matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
1558 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
1559 pub enum MacDelimiter {
1566 pub fn to_token(self) -> DelimToken {
1568 MacDelimiter::Parenthesis => DelimToken::Paren,
1569 MacDelimiter::Bracket => DelimToken::Bracket,
1570 MacDelimiter::Brace => DelimToken::Brace,
1574 pub fn from_token(delim: DelimToken) -> Option<MacDelimiter> {
1576 token::Paren => Some(MacDelimiter::Parenthesis),
1577 token::Bracket => Some(MacDelimiter::Bracket),
1578 token::Brace => Some(MacDelimiter::Brace),
1579 token::NoDelim => None,
1584 /// Represents a macro definition.
1585 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1586 pub struct MacroDef {
1587 pub body: P<MacArgs>,
1588 /// `true` if macro was defined with `macro_rules`.
1589 pub macro_rules: bool,
1592 #[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
1593 #[derive(HashStable_Generic)]
1595 /// A regular string, like `"foo"`.
1597 /// A raw string, like `r##"foo"##`.
1599 /// The value is the number of `#` symbols used.
1604 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1606 /// The original literal token as written in source code.
1607 pub token: token::Lit,
1608 /// The "semantic" representation of the literal lowered from the original tokens.
1609 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1610 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1615 /// Same as `Lit`, but restricted to string literals.
1616 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1618 /// The original literal token as written in source code.
1619 pub style: StrStyle,
1621 pub suffix: Option<Symbol>,
1623 /// The unescaped "semantic" representation of the literal lowered from the original token.
1624 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1625 pub symbol_unescaped: Symbol,
1629 pub fn as_lit(&self) -> Lit {
1630 let token_kind = match self.style {
1631 StrStyle::Cooked => token::Str,
1632 StrStyle::Raw(n) => token::StrRaw(n),
1635 token: token::Lit::new(token_kind, self.symbol, self.suffix),
1637 kind: LitKind::Str(self.symbol_unescaped, self.style),
1642 /// Type of the integer literal based on provided suffix.
1643 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1644 #[derive(HashStable_Generic)]
1645 pub enum LitIntType {
1654 /// Type of the float literal based on provided suffix.
1655 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1656 #[derive(HashStable_Generic)]
1657 pub enum LitFloatType {
1658 /// A float literal with a suffix (`1f32` or `1E10f32`).
1660 /// A float literal without a suffix (`1.0 or 1.0E10`).
1666 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
1667 #[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
1669 /// A string literal (`"foo"`).
1670 Str(Symbol, StrStyle),
1671 /// A byte string (`b"foo"`).
1673 /// A byte char (`b'f'`).
1675 /// A character literal (`'a'`).
1677 /// An integer literal (`1`).
1678 Int(u128, LitIntType),
1679 /// A float literal (`1f64` or `1E10f64`).
1680 Float(Symbol, LitFloatType),
1681 /// A boolean literal.
1683 /// Placeholder for a literal that wasn't well-formed in some way.
1688 /// Returns `true` if this literal is a string.
1689 pub fn is_str(&self) -> bool {
1690 matches!(self, LitKind::Str(..))
1693 /// Returns `true` if this literal is byte literal string.
1694 pub fn is_bytestr(&self) -> bool {
1695 matches!(self, LitKind::ByteStr(_))
1698 /// Returns `true` if this is a numeric literal.
1699 pub fn is_numeric(&self) -> bool {
1700 matches!(self, LitKind::Int(..) | LitKind::Float(..))
1703 /// Returns `true` if this literal has no suffix.
1704 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1705 pub fn is_unsuffixed(&self) -> bool {
1709 /// Returns `true` if this literal has a suffix.
1710 pub fn is_suffixed(&self) -> bool {
1712 // suffixed variants
1713 LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
1714 | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
1715 // unsuffixed variants
1717 | LitKind::ByteStr(..)
1720 | LitKind::Int(_, LitIntType::Unsuffixed)
1721 | LitKind::Float(_, LitFloatType::Unsuffixed)
1723 | LitKind::Err(..) => false,
1728 // N.B., If you change this, you'll probably want to change the corresponding
1729 // type structure in `middle/ty.rs` as well.
1730 #[derive(Clone, Encodable, Decodable, Debug)]
1733 pub mutbl: Mutability,
1736 /// Represents a function's signature in a trait declaration,
1737 /// trait implementation, or free function.
1738 #[derive(Clone, Encodable, Decodable, Debug)]
1740 pub header: FnHeader,
1741 pub decl: P<FnDecl>,
1745 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1746 #[derive(Encodable, Decodable, HashStable_Generic)]
1753 pub fn name_str(self) -> &'static str {
1755 FloatTy::F32 => "f32",
1756 FloatTy::F64 => "f64",
1760 pub fn name(self) -> Symbol {
1762 FloatTy::F32 => sym::f32,
1763 FloatTy::F64 => sym::f64,
1768 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1769 #[derive(Encodable, Decodable, HashStable_Generic)]
1780 pub fn name_str(&self) -> &'static str {
1782 IntTy::Isize => "isize",
1784 IntTy::I16 => "i16",
1785 IntTy::I32 => "i32",
1786 IntTy::I64 => "i64",
1787 IntTy::I128 => "i128",
1791 pub fn name(&self) -> Symbol {
1793 IntTy::Isize => sym::isize,
1794 IntTy::I8 => sym::i8,
1795 IntTy::I16 => sym::i16,
1796 IntTy::I32 => sym::i32,
1797 IntTy::I64 => sym::i64,
1798 IntTy::I128 => sym::i128,
1803 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
1804 #[derive(Encodable, Decodable, HashStable_Generic)]
1815 pub fn name_str(&self) -> &'static str {
1817 UintTy::Usize => "usize",
1819 UintTy::U16 => "u16",
1820 UintTy::U32 => "u32",
1821 UintTy::U64 => "u64",
1822 UintTy::U128 => "u128",
1826 pub fn name(&self) -> Symbol {
1828 UintTy::Usize => sym::usize,
1829 UintTy::U8 => sym::u8,
1830 UintTy::U16 => sym::u16,
1831 UintTy::U32 => sym::u32,
1832 UintTy::U64 => sym::u64,
1833 UintTy::U128 => sym::u128,
1838 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1839 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1840 #[derive(Clone, Encodable, Decodable, Debug)]
1841 pub struct AssocTyConstraint {
1844 pub gen_args: Option<GenericArgs>,
1845 pub kind: AssocTyConstraintKind,
1849 /// The kinds of an `AssocTyConstraint`.
1850 #[derive(Clone, Encodable, Decodable, 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(Encodable, Decodable, Debug)]
1863 pub tokens: Option<LazyTokenStream>,
1867 fn clone(&self) -> Self {
1868 ensure_sufficient_stack(|| Self {
1870 kind: self.kind.clone(),
1872 tokens: self.tokens.clone(),
1878 pub fn peel_refs(&self) -> &Self {
1879 let mut final_ty = self;
1880 while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
1887 #[derive(Clone, Encodable, Decodable, Debug)]
1888 pub struct BareFnTy {
1889 pub unsafety: Unsafe,
1891 pub generic_params: Vec<GenericParam>,
1892 pub decl: P<FnDecl>,
1895 /// The various kinds of type recognized by the compiler.
1896 #[derive(Clone, Encodable, Decodable, Debug)]
1898 /// A variable-length slice (`[T]`).
1900 /// A fixed length array (`[T; n]`).
1901 Array(P<Ty>, AnonConst),
1902 /// A raw pointer (`*const T` or `*mut T`).
1904 /// A reference (`&'a T` or `&'a mut T`).
1905 Rptr(Option<Lifetime>, MutTy),
1906 /// A bare function (e.g., `fn(usize) -> bool`).
1907 BareFn(P<BareFnTy>),
1908 /// The never type (`!`).
1910 /// A tuple (`(A, B, C, D,...)`).
1912 /// An anonymous struct type i.e. `struct { foo: Type }`
1913 AnonymousStruct(Vec<FieldDef>, bool),
1914 /// An anonymous union type i.e. `union { bar: Type }`
1915 AnonymousUnion(Vec<FieldDef>, bool),
1916 /// A path (`module::module::...::Type`), optionally
1917 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
1919 /// Type parameters are stored in the `Path` itself.
1920 Path(Option<QSelf>, Path),
1921 /// A trait object type `Bound1 + Bound2 + Bound3`
1922 /// where `Bound` is a trait or a lifetime.
1923 TraitObject(GenericBounds, TraitObjectSyntax),
1924 /// An `impl Bound1 + Bound2 + Bound3` type
1925 /// where `Bound` is a trait or a lifetime.
1927 /// The `NodeId` exists to prevent lowering from having to
1928 /// generate `NodeId`s on the fly, which would complicate
1929 /// the generation of opaque `type Foo = impl Trait` items significantly.
1930 ImplTrait(NodeId, GenericBounds),
1931 /// No-op; kept solely so that we can pretty-print faithfully.
1935 /// This means the type should be inferred instead of it having been
1936 /// specified. This can appear anywhere in a type.
1938 /// Inferred type of a `self` or `&self` argument in a method.
1940 /// A macro in the type position.
1942 /// Placeholder for a kind that has failed to be defined.
1944 /// Placeholder for a `va_list`.
1949 pub fn is_implicit_self(&self) -> bool {
1950 matches!(self, TyKind::ImplicitSelf)
1953 pub fn is_unit(&self) -> bool {
1954 matches!(self, TyKind::Tup(tys) if tys.is_empty())
1958 /// Syntax used to declare a trait object.
1959 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1960 pub enum TraitObjectSyntax {
1965 /// Inline assembly operand explicit register or register class.
1967 /// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
1968 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1969 pub enum InlineAsmRegOrRegClass {
1974 bitflags::bitflags! {
1975 #[derive(Encodable, Decodable, HashStable_Generic)]
1976 pub struct InlineAsmOptions: u8 {
1977 const PURE = 1 << 0;
1978 const NOMEM = 1 << 1;
1979 const READONLY = 1 << 2;
1980 const PRESERVES_FLAGS = 1 << 3;
1981 const NORETURN = 1 << 4;
1982 const NOSTACK = 1 << 5;
1983 const ATT_SYNTAX = 1 << 6;
1988 #[derive(Clone, PartialEq, PartialOrd, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
1989 pub enum InlineAsmTemplatePiece {
1991 Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
1994 impl fmt::Display for InlineAsmTemplatePiece {
1995 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1997 Self::String(s) => {
1998 for c in s.chars() {
2000 '{' => f.write_str("{{")?,
2001 '}' => f.write_str("}}")?,
2007 Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
2008 write!(f, "{{{}:{}}}", operand_idx, modifier)
2010 Self::Placeholder { operand_idx, modifier: None, .. } => {
2011 write!(f, "{{{}}}", operand_idx)
2017 impl InlineAsmTemplatePiece {
2018 /// Rebuilds the asm template string from its pieces.
2019 pub fn to_string(s: &[Self]) -> String {
2021 let mut out = String::new();
2023 let _ = write!(out, "{}", p);
2029 /// Inline assembly operand.
2031 /// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
2032 #[derive(Clone, Encodable, Decodable, Debug)]
2033 pub enum InlineAsmOperand {
2035 reg: InlineAsmRegOrRegClass,
2039 reg: InlineAsmRegOrRegClass,
2041 expr: Option<P<Expr>>,
2044 reg: InlineAsmRegOrRegClass,
2049 reg: InlineAsmRegOrRegClass,
2052 out_expr: Option<P<Expr>>,
2055 anon_const: AnonConst,
2062 /// Inline assembly.
2064 /// E.g., `asm!("NOP");`.
2065 #[derive(Clone, Encodable, Decodable, Debug)]
2066 pub struct InlineAsm {
2067 pub template: Vec<InlineAsmTemplatePiece>,
2068 pub template_strs: Box<[(Symbol, Option<Symbol>, Span)]>,
2069 pub operands: Vec<(InlineAsmOperand, Span)>,
2070 pub clobber_abi: Option<(Symbol, Span)>,
2071 pub options: InlineAsmOptions,
2072 pub line_spans: Vec<Span>,
2075 /// Inline assembly dialect.
2077 /// E.g., `"intel"` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2078 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, Hash, HashStable_Generic)]
2079 pub enum LlvmAsmDialect {
2084 /// LLVM-style inline assembly.
2086 /// E.g., `"={eax}"(result)` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2087 #[derive(Clone, Encodable, Decodable, Debug)]
2088 pub struct LlvmInlineAsmOutput {
2089 pub constraint: Symbol,
2092 pub is_indirect: bool,
2095 /// LLVM-style inline assembly.
2097 /// E.g., `llvm_asm!("NOP");`.
2098 #[derive(Clone, Encodable, Decodable, Debug)]
2099 pub struct LlvmInlineAsm {
2101 pub asm_str_style: StrStyle,
2102 pub outputs: Vec<LlvmInlineAsmOutput>,
2103 pub inputs: Vec<(Symbol, P<Expr>)>,
2104 pub clobbers: Vec<Symbol>,
2106 pub alignstack: bool,
2107 pub dialect: LlvmAsmDialect,
2110 /// A parameter in a function header.
2112 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
2113 #[derive(Clone, Encodable, Decodable, Debug)]
2120 pub is_placeholder: bool,
2123 /// Alternative representation for `Arg`s describing `self` parameter of methods.
2125 /// E.g., `&mut self` as in `fn foo(&mut self)`.
2126 #[derive(Clone, Encodable, Decodable, Debug)]
2128 /// `self`, `mut self`
2130 /// `&'lt self`, `&'lt mut self`
2131 Region(Option<Lifetime>, Mutability),
2132 /// `self: TYPE`, `mut self: TYPE`
2133 Explicit(P<Ty>, Mutability),
2136 pub type ExplicitSelf = Spanned<SelfKind>;
2139 /// Attempts to cast parameter to `ExplicitSelf`.
2140 pub fn to_self(&self) -> Option<ExplicitSelf> {
2141 if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
2142 if ident.name == kw::SelfLower {
2143 return match self.ty.kind {
2144 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
2145 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
2146 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
2149 self.pat.span.to(self.ty.span),
2150 SelfKind::Explicit(self.ty.clone(), mutbl),
2158 /// Returns `true` if parameter is `self`.
2159 pub fn is_self(&self) -> bool {
2160 if let PatKind::Ident(_, ident, _) = self.pat.kind {
2161 ident.name == kw::SelfLower
2167 /// Builds a `Param` object from `ExplicitSelf`.
2168 pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
2169 let span = eself.span.to(eself_ident.span);
2170 let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
2171 let param = |mutbl, ty| Param {
2175 kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
2182 is_placeholder: false,
2185 SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
2186 SelfKind::Value(mutbl) => param(mutbl, infer_ty),
2187 SelfKind::Region(lt, mutbl) => param(
2191 kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
2200 /// A signature (not the body) of a function declaration.
2202 /// E.g., `fn foo(bar: baz)`.
2204 /// Please note that it's different from `FnHeader` structure
2205 /// which contains metadata about function safety, asyncness, constness and ABI.
2206 #[derive(Clone, Encodable, Decodable, Debug)]
2208 pub inputs: Vec<Param>,
2209 pub output: FnRetTy,
2213 pub fn has_self(&self) -> bool {
2214 self.inputs.get(0).map_or(false, Param::is_self)
2216 pub fn c_variadic(&self) -> bool {
2217 self.inputs.last().map_or(false, |arg| matches!(arg.ty.kind, TyKind::CVarArgs))
2221 /// Is the trait definition an auto trait?
2222 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2228 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug)]
2229 #[derive(HashStable_Generic)]
2235 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2237 Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
2242 pub fn is_async(self) -> bool {
2243 matches!(self, Async::Yes { .. })
2246 /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
2247 pub fn opt_return_id(self) -> Option<NodeId> {
2249 Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
2255 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2256 #[derive(HashStable_Generic)]
2262 /// Item defaultness.
2263 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
2264 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2265 pub enum Defaultness {
2270 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
2271 pub enum ImplPolarity {
2272 /// `impl Trait for Type`
2274 /// `impl !Trait for Type`
2278 impl fmt::Debug for ImplPolarity {
2279 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2281 ImplPolarity::Positive => "positive".fmt(f),
2282 ImplPolarity::Negative(_) => "negative".fmt(f),
2287 #[derive(Clone, Encodable, Decodable, Debug)]
2289 /// Returns type is not specified.
2291 /// Functions default to `()` and closures default to inference.
2292 /// Span points to where return type would be inserted.
2294 /// Everything else.
2299 pub fn span(&self) -> Span {
2301 FnRetTy::Default(span) => span,
2302 FnRetTy::Ty(ref ty) => ty.span,
2307 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
2313 /// Module item kind.
2314 #[derive(Clone, Encodable, Decodable, Debug)]
2316 /// Module with inlined definition `mod foo { ... }`,
2317 /// or with definition outlined to a separate file `mod foo;` and already loaded from it.
2318 /// The inner span is from the first token past `{` to the last token until `}`,
2319 /// or from the first to the last token in the loaded file.
2320 Loaded(Vec<P<Item>>, Inline, Span),
2321 /// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
2325 /// Foreign module declaration.
2327 /// E.g., `extern { .. }` or `extern "C" { .. }`.
2328 #[derive(Clone, Encodable, Decodable, Debug)]
2329 pub struct ForeignMod {
2330 /// `unsafe` keyword accepted syntactically for macro DSLs, but not
2331 /// semantically by Rust.
2332 pub unsafety: Unsafe,
2333 pub abi: Option<StrLit>,
2334 pub items: Vec<P<ForeignItem>>,
2337 #[derive(Clone, Encodable, Decodable, Debug)]
2338 pub struct EnumDef {
2339 pub variants: Vec<Variant>,
2342 #[derive(Clone, Encodable, Decodable, Debug)]
2343 pub struct Variant {
2344 /// Attributes of the variant.
2346 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2350 /// The visibility of the variant. Syntactically accepted but not semantically.
2351 pub vis: Visibility,
2352 /// Name of the variant.
2355 /// Fields and constructor id of the variant.
2356 pub data: VariantData,
2357 /// Explicit discriminant, e.g., `Foo = 1`.
2358 pub disr_expr: Option<AnonConst>,
2359 /// Is a macro placeholder
2360 pub is_placeholder: bool,
2363 /// Part of `use` item to the right of its prefix.
2364 #[derive(Clone, Encodable, Decodable, Debug)]
2365 pub enum UseTreeKind {
2366 /// `use prefix` or `use prefix as rename`
2368 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2370 Simple(Option<Ident>, NodeId, NodeId),
2371 /// `use prefix::{...}`
2372 Nested(Vec<(UseTree, NodeId)>),
2377 /// A tree of paths sharing common prefixes.
2378 /// Used in `use` items both at top-level and inside of braces in import groups.
2379 #[derive(Clone, Encodable, Decodable, Debug)]
2380 pub struct UseTree {
2382 pub kind: UseTreeKind,
2387 pub fn ident(&self) -> Ident {
2389 UseTreeKind::Simple(Some(rename), ..) => rename,
2390 UseTreeKind::Simple(None, ..) => {
2391 self.prefix.segments.last().expect("empty prefix in a simple import").ident
2393 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2398 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2399 /// are contained as statements within items. These two cases need to be
2400 /// distinguished for pretty-printing.
2401 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
2402 pub enum AttrStyle {
2407 rustc_index::newtype_index! {
2410 DEBUG_FORMAT = "AttrId({})"
2414 impl<S: Encoder> rustc_serialize::Encodable<S> for AttrId {
2415 fn encode(&self, s: &mut S) -> Result<(), S::Error> {
2420 impl<D: Decoder> rustc_serialize::Decodable<D> for AttrId {
2421 fn decode(d: &mut D) -> Result<AttrId, D::Error> {
2422 d.read_nil().map(|_| crate::attr::mk_attr_id())
2426 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2427 pub struct AttrItem {
2430 pub tokens: Option<LazyTokenStream>,
2433 /// A list of attributes.
2434 pub type AttrVec = ThinVec<Attribute>;
2436 /// Metadata associated with an item.
2437 #[derive(Clone, Encodable, Decodable, Debug)]
2438 pub struct Attribute {
2441 /// Denotes if the attribute decorates the following construct (outer)
2442 /// or the construct this attribute is contained within (inner).
2443 pub style: AttrStyle,
2447 #[derive(Clone, Encodable, Decodable, Debug)]
2449 /// A normal attribute.
2450 Normal(AttrItem, Option<LazyTokenStream>),
2452 /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
2453 /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
2454 /// variant (which is much less compact and thus more expensive).
2455 DocComment(CommentKind, Symbol),
2458 /// `TraitRef`s appear in impls.
2460 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2461 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2462 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2463 /// same as the impl's `NodeId`).
2464 #[derive(Clone, Encodable, Decodable, Debug)]
2465 pub struct TraitRef {
2470 #[derive(Clone, Encodable, Decodable, Debug)]
2471 pub struct PolyTraitRef {
2472 /// The `'a` in `<'a> Foo<&'a T>`.
2473 pub bound_generic_params: Vec<GenericParam>,
2475 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2476 pub trait_ref: TraitRef,
2482 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2484 bound_generic_params: generic_params,
2485 trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
2491 #[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2492 pub enum CrateSugar {
2493 /// Source is `pub(crate)`.
2496 /// Source is (just) `crate`.
2500 #[derive(Clone, Encodable, Decodable, Debug)]
2501 pub struct Visibility {
2502 pub kind: VisibilityKind,
2504 pub tokens: Option<LazyTokenStream>,
2507 #[derive(Clone, Encodable, Decodable, Debug)]
2508 pub enum VisibilityKind {
2511 Restricted { path: P<Path>, id: NodeId },
2515 impl VisibilityKind {
2516 pub fn is_pub(&self) -> bool {
2517 matches!(self, VisibilityKind::Public)
2521 /// Field definition in a struct, variant or union.
2523 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2524 #[derive(Clone, Encodable, Decodable, Debug)]
2525 pub struct FieldDef {
2529 pub vis: Visibility,
2530 pub ident: Option<Ident>,
2533 pub is_placeholder: bool,
2536 /// Fields and constructor ids of enum variants and structs.
2537 #[derive(Clone, Encodable, Decodable, Debug)]
2538 pub enum VariantData {
2541 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2542 Struct(Vec<FieldDef>, bool),
2545 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2546 Tuple(Vec<FieldDef>, NodeId),
2549 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2554 /// Return the fields of this variant.
2555 pub fn fields(&self) -> &[FieldDef] {
2557 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
2562 /// Return the `NodeId` of this variant's constructor, if it has one.
2563 pub fn ctor_id(&self) -> Option<NodeId> {
2565 VariantData::Struct(..) => None,
2566 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2571 /// An item definition.
2572 #[derive(Clone, Encodable, Decodable, Debug)]
2573 pub struct Item<K = ItemKind> {
2574 pub attrs: Vec<Attribute>,
2577 pub vis: Visibility,
2578 /// The name of the item.
2579 /// It might be a dummy name in case of anonymous items.
2584 /// Original tokens this item was parsed from. This isn't necessarily
2585 /// available for all items, although over time more and more items should
2586 /// have this be `Some`. Right now this is primarily used for procedural
2587 /// macros, notably custom attributes.
2589 /// Note that the tokens here do not include the outer attributes, but will
2590 /// include inner attributes.
2591 pub tokens: Option<LazyTokenStream>,
2595 /// Return the span that encompasses the attributes.
2596 pub fn span_with_attributes(&self) -> Span {
2597 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2601 impl<K: Into<ItemKind>> Item<K> {
2602 pub fn into_item(self) -> Item {
2603 let Item { attrs, id, span, vis, ident, kind, tokens } = self;
2604 Item { attrs, id, span, vis, ident, kind: kind.into(), tokens }
2608 /// `extern` qualifier on a function item or function type.
2609 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2617 pub fn from_abi(abi: Option<StrLit>) -> Extern {
2618 abi.map_or(Extern::Implicit, Extern::Explicit)
2622 /// A function header.
2624 /// All the information between the visibility and the name of the function is
2625 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2626 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2627 pub struct FnHeader {
2628 pub unsafety: Unsafe,
2629 pub asyncness: Async,
2630 pub constness: Const,
2635 /// Does this function header have any qualifiers or is it empty?
2636 pub fn has_qualifiers(&self) -> bool {
2637 let Self { unsafety, asyncness, constness, ext } = self;
2638 matches!(unsafety, Unsafe::Yes(_))
2639 || asyncness.is_async()
2640 || matches!(constness, Const::Yes(_))
2641 || !matches!(ext, Extern::None)
2645 impl Default for FnHeader {
2646 fn default() -> FnHeader {
2648 unsafety: Unsafe::No,
2649 asyncness: Async::No,
2650 constness: Const::No,
2656 #[derive(Clone, Encodable, Decodable, Debug)]
2657 pub struct TraitKind(
2662 pub Vec<P<AssocItem>>,
2665 #[derive(Clone, Encodable, Decodable, Debug)]
2666 pub struct TyAliasKind(pub Defaultness, pub Generics, pub GenericBounds, pub Option<P<Ty>>);
2668 #[derive(Clone, Encodable, Decodable, Debug)]
2669 pub struct ImplKind {
2670 pub unsafety: Unsafe,
2671 pub polarity: ImplPolarity,
2672 pub defaultness: Defaultness,
2673 pub constness: Const,
2674 pub generics: Generics,
2676 /// The trait being implemented, if any.
2677 pub of_trait: Option<TraitRef>,
2680 pub items: Vec<P<AssocItem>>,
2683 #[derive(Clone, Encodable, Decodable, Debug)]
2684 pub struct FnKind(pub Defaultness, pub FnSig, pub Generics, pub Option<P<Block>>);
2686 #[derive(Clone, Encodable, Decodable, Debug)]
2688 /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
2690 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2691 ExternCrate(Option<Symbol>),
2692 /// A use declaration item (`use`).
2694 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2696 /// A static item (`static`).
2698 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2699 Static(P<Ty>, Mutability, Option<P<Expr>>),
2700 /// A constant item (`const`).
2702 /// E.g., `const FOO: i32 = 42;`.
2703 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2704 /// A function declaration (`fn`).
2706 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2708 /// A module declaration (`mod`).
2710 /// E.g., `mod foo;` or `mod foo { .. }`.
2711 /// `unsafe` keyword on modules is accepted syntactically for macro DSLs, but not
2712 /// semantically by Rust.
2713 Mod(Unsafe, ModKind),
2714 /// An external module (`extern`).
2716 /// E.g., `extern {}` or `extern "C" {}`.
2717 ForeignMod(ForeignMod),
2718 /// Module-level inline assembly (from `global_asm!()`).
2719 GlobalAsm(InlineAsm),
2720 /// A type alias (`type`).
2722 /// E.g., `type Foo = Bar<u8>;`.
2723 TyAlias(Box<TyAliasKind>),
2724 /// An enum definition (`enum`).
2726 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2727 Enum(EnumDef, Generics),
2728 /// A struct definition (`struct`).
2730 /// E.g., `struct Foo<A> { x: A }`.
2731 Struct(VariantData, Generics),
2732 /// A union definition (`union`).
2734 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2735 Union(VariantData, Generics),
2736 /// A trait declaration (`trait`).
2738 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2739 Trait(Box<TraitKind>),
2742 /// E.g., `trait Foo = Bar + Quux;`.
2743 TraitAlias(Generics, GenericBounds),
2744 /// An implementation.
2746 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2747 Impl(Box<ImplKind>),
2748 /// A macro invocation.
2750 /// E.g., `foo!(..)`.
2753 /// A macro definition.
2757 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2758 rustc_data_structures::static_assert_size!(ItemKind, 112);
2761 pub fn article(&self) -> &str {
2764 Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
2765 | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
2766 ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
2770 pub fn descr(&self) -> &str {
2772 ItemKind::ExternCrate(..) => "extern crate",
2773 ItemKind::Use(..) => "`use` import",
2774 ItemKind::Static(..) => "static item",
2775 ItemKind::Const(..) => "constant item",
2776 ItemKind::Fn(..) => "function",
2777 ItemKind::Mod(..) => "module",
2778 ItemKind::ForeignMod(..) => "extern block",
2779 ItemKind::GlobalAsm(..) => "global asm item",
2780 ItemKind::TyAlias(..) => "type alias",
2781 ItemKind::Enum(..) => "enum",
2782 ItemKind::Struct(..) => "struct",
2783 ItemKind::Union(..) => "union",
2784 ItemKind::Trait(..) => "trait",
2785 ItemKind::TraitAlias(..) => "trait alias",
2786 ItemKind::MacCall(..) => "item macro invocation",
2787 ItemKind::MacroDef(..) => "macro definition",
2788 ItemKind::Impl { .. } => "implementation",
2792 pub fn generics(&self) -> Option<&Generics> {
2794 Self::Fn(box FnKind(_, _, generics, _))
2795 | Self::TyAlias(box TyAliasKind(_, generics, ..))
2796 | Self::Enum(_, generics)
2797 | Self::Struct(_, generics)
2798 | Self::Union(_, generics)
2799 | Self::Trait(box TraitKind(_, _, generics, ..))
2800 | Self::TraitAlias(generics, _)
2801 | Self::Impl(box ImplKind { generics, .. }) => Some(generics),
2807 /// Represents associated items.
2808 /// These include items in `impl` and `trait` definitions.
2809 pub type AssocItem = Item<AssocItemKind>;
2811 /// Represents associated item kinds.
2813 /// The term "provided" in the variants below refers to the item having a default
2814 /// definition / body. Meanwhile, a "required" item lacks a definition / body.
2815 /// In an implementation, all items must be provided.
2816 /// The `Option`s below denote the bodies, where `Some(_)`
2817 /// means "provided" and conversely `None` means "required".
2818 #[derive(Clone, Encodable, Decodable, Debug)]
2819 pub enum AssocItemKind {
2820 /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
2821 /// If `def` is parsed, then the constant is provided, and otherwise required.
2822 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2823 /// An associated function.
2825 /// An associated type.
2826 TyAlias(Box<TyAliasKind>),
2827 /// A macro expanding to associated items.
2831 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2832 rustc_data_structures::static_assert_size!(AssocItemKind, 72);
2834 impl AssocItemKind {
2835 pub fn defaultness(&self) -> Defaultness {
2837 Self::Const(def, ..)
2838 | Self::Fn(box FnKind(def, ..))
2839 | Self::TyAlias(box TyAliasKind(def, ..)) => def,
2840 Self::MacCall(..) => Defaultness::Final,
2845 impl From<AssocItemKind> for ItemKind {
2846 fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
2847 match assoc_item_kind {
2848 AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
2849 AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
2850 AssocItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
2851 AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
2856 impl TryFrom<ItemKind> for AssocItemKind {
2857 type Error = ItemKind;
2859 fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
2860 Ok(match item_kind {
2861 ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
2862 ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
2863 ItemKind::TyAlias(ty_alias_kind) => AssocItemKind::TyAlias(ty_alias_kind),
2864 ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
2865 _ => return Err(item_kind),
2870 /// An item in `extern` block.
2871 #[derive(Clone, Encodable, Decodable, Debug)]
2872 pub enum ForeignItemKind {
2873 /// A foreign static item (`static FOO: u8`).
2874 Static(P<Ty>, Mutability, Option<P<Expr>>),
2875 /// An foreign function.
2877 /// An foreign type.
2878 TyAlias(Box<TyAliasKind>),
2879 /// A macro expanding to foreign items.
2883 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2884 rustc_data_structures::static_assert_size!(ForeignItemKind, 72);
2886 impl From<ForeignItemKind> for ItemKind {
2887 fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
2888 match foreign_item_kind {
2889 ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
2890 ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
2891 ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
2892 ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
2897 impl TryFrom<ItemKind> for ForeignItemKind {
2898 type Error = ItemKind;
2900 fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
2901 Ok(match item_kind {
2902 ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
2903 ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
2904 ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
2905 ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
2906 _ => return Err(item_kind),
2911 pub type ForeignItem = Item<ForeignItemKind>;