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.has_features().const_generics`
336 // is active. Specifically, if it's only `min_const_generics`, it will still require
337 // ordering consts after types.
338 Const { unordered: bool },
342 impl Ord for ParamKindOrd {
343 fn cmp(&self, other: &Self) -> Ordering {
345 let to_int = |v| match v {
347 Infer | Type | Const { unordered: true } => 1,
348 // technically both consts should be ordered equally,
349 // but only one is ever encountered at a time, so this is
351 Const { unordered: false } => 2,
354 to_int(*self).cmp(&to_int(*other))
357 impl PartialOrd for ParamKindOrd {
358 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
359 Some(self.cmp(other))
362 impl PartialEq for ParamKindOrd {
363 fn eq(&self, other: &Self) -> bool {
364 self.cmp(other) == Ordering::Equal
367 impl Eq for ParamKindOrd {}
369 impl fmt::Display for ParamKindOrd {
370 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
372 ParamKindOrd::Lifetime => "lifetime".fmt(f),
373 ParamKindOrd::Type => "type".fmt(f),
374 ParamKindOrd::Const { .. } => "const".fmt(f),
375 ParamKindOrd::Infer => "infer".fmt(f),
380 #[derive(Clone, Encodable, Decodable, Debug)]
381 pub enum GenericParamKind {
382 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
385 default: Option<P<Ty>>,
389 /// Span of the `const` keyword.
391 /// Optional default value for the const generic param
392 default: Option<AnonConst>,
396 #[derive(Clone, Encodable, Decodable, Debug)]
397 pub struct GenericParam {
401 pub bounds: GenericBounds,
402 pub is_placeholder: bool,
403 pub kind: GenericParamKind,
406 /// Represents lifetime, type and const parameters attached to a declaration of
407 /// a function, enum, trait, etc.
408 #[derive(Clone, Encodable, Decodable, Debug)]
409 pub struct Generics {
410 pub params: Vec<GenericParam>,
411 pub where_clause: WhereClause,
415 impl Default for Generics {
416 /// Creates an instance of `Generics`.
417 fn default() -> Generics {
420 where_clause: WhereClause {
421 has_where_token: false,
422 predicates: Vec::new(),
430 /// A where-clause in a definition.
431 #[derive(Clone, Encodable, Decodable, Debug)]
432 pub struct WhereClause {
433 /// `true` if we ate a `where` token: this can happen
434 /// if we parsed no predicates (e.g. `struct Foo where {}`).
435 /// This allows us to accurately pretty-print
436 /// in `nt_to_tokenstream`
437 pub has_where_token: bool,
438 pub predicates: Vec<WherePredicate>,
442 /// A single predicate in a where-clause.
443 #[derive(Clone, Encodable, Decodable, Debug)]
444 pub enum WherePredicate {
445 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
446 BoundPredicate(WhereBoundPredicate),
447 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
448 RegionPredicate(WhereRegionPredicate),
449 /// An equality predicate (unsupported).
450 EqPredicate(WhereEqPredicate),
453 impl WherePredicate {
454 pub fn span(&self) -> Span {
456 WherePredicate::BoundPredicate(p) => p.span,
457 WherePredicate::RegionPredicate(p) => p.span,
458 WherePredicate::EqPredicate(p) => p.span,
465 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
466 #[derive(Clone, Encodable, Decodable, Debug)]
467 pub struct WhereBoundPredicate {
469 /// Any generics from a `for` binding.
470 pub bound_generic_params: Vec<GenericParam>,
471 /// The type being bounded.
472 pub bounded_ty: P<Ty>,
473 /// Trait and lifetime bounds (`Clone + Send + 'static`).
474 pub bounds: GenericBounds,
477 /// A lifetime predicate.
479 /// E.g., `'a: 'b + 'c`.
480 #[derive(Clone, Encodable, Decodable, Debug)]
481 pub struct WhereRegionPredicate {
483 pub lifetime: Lifetime,
484 pub bounds: GenericBounds,
487 /// An equality predicate (unsupported).
490 #[derive(Clone, Encodable, Decodable, Debug)]
491 pub struct WhereEqPredicate {
498 #[derive(Clone, Encodable, Decodable, Debug)]
500 pub attrs: Vec<Attribute>,
501 pub items: Vec<P<Item>>,
503 /// The order of items in the HIR is unrelated to the order of
504 /// items in the AST. However, we generate proc macro harnesses
505 /// based on the AST order, and later refer to these harnesses
506 /// from the HIR. This field keeps track of the order in which
507 /// we generated proc macros harnesses, so that we can map
508 /// HIR proc macros items back to their harness items.
509 pub proc_macros: Vec<NodeId>,
512 /// Possible values inside of compile-time attribute lists.
514 /// E.g., the '..' in `#[name(..)]`.
515 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
516 pub enum NestedMetaItem {
517 /// A full MetaItem, for recursive meta items.
521 /// E.g., `"foo"`, `64`, `true`.
525 /// A spanned compile-time attribute item.
527 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
528 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
529 pub struct MetaItem {
531 pub kind: MetaItemKind,
535 /// A compile-time attribute item.
537 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
538 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
539 pub enum MetaItemKind {
542 /// E.g., `test` as in `#[test]`.
546 /// E.g., `derive(..)` as in `#[derive(..)]`.
547 List(Vec<NestedMetaItem>),
548 /// Name value meta item.
550 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
554 /// A block (`{ .. }`).
556 /// E.g., `{ .. }` as in `fn foo() { .. }`.
557 #[derive(Clone, Encodable, Decodable, Debug)]
559 /// The statements in the block.
560 pub stmts: Vec<Stmt>,
562 /// Distinguishes between `unsafe { ... }` and `{ ... }`.
563 pub rules: BlockCheckMode,
565 pub tokens: Option<LazyTokenStream>,
570 /// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
571 #[derive(Clone, Encodable, Decodable, Debug)]
576 pub tokens: Option<LazyTokenStream>,
580 /// Attempt reparsing the pattern as a type.
581 /// This is intended for use by diagnostics.
582 pub fn to_ty(&self) -> Option<P<Ty>> {
583 let kind = match &self.kind {
584 // In a type expression `_` is an inference variable.
585 PatKind::Wild => TyKind::Infer,
586 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
587 PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
588 TyKind::Path(None, Path::from_ident(*ident))
590 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
591 PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
592 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
593 PatKind::Ref(pat, mutbl) => {
594 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
596 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
597 // when `P` can be reparsed as a type `T`.
598 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
599 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
600 // assuming `T0` to `Tn` are all syntactically valid as types.
601 PatKind::Tuple(pats) => {
602 let mut tys = Vec::with_capacity(pats.len());
603 // FIXME(#48994) - could just be collected into an Option<Vec>
605 tys.push(pat.to_ty()?);
612 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
615 /// Walk top-down and call `it` in each place where a pattern occurs
616 /// starting with the root pattern `walk` is called on. If `it` returns
617 /// false then we will descend no further but siblings will be processed.
618 pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
624 // Walk into the pattern associated with `Ident` (if any).
625 PatKind::Ident(_, _, Some(p)) => p.walk(it),
627 // Walk into each field of struct.
628 PatKind::Struct(_, _, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
630 // Sequence of patterns.
631 PatKind::TupleStruct(_, _, s)
634 | PatKind::Or(s) => s.iter().for_each(|p| p.walk(it)),
636 // Trivial wrappers over inner patterns.
637 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
639 // These patterns do not contain subpatterns, skip.
646 | PatKind::MacCall(_) => {}
650 /// Is this a `..` pattern?
651 pub fn is_rest(&self) -> bool {
652 matches!(self.kind, PatKind::Rest)
656 /// A single field in a struct pattern.
658 /// Patterns like the fields of `Foo { x, ref y, ref mut z }`
659 /// are treated the same as `x: x, y: ref y, z: ref mut z`,
660 /// except when `is_shorthand` is true.
661 #[derive(Clone, Encodable, Decodable, Debug)]
662 pub struct PatField {
663 /// The identifier for the field.
665 /// The pattern the field is destructured to.
667 pub is_shorthand: bool,
671 pub is_placeholder: bool,
674 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
675 pub enum BindingMode {
680 #[derive(Clone, Encodable, Decodable, Debug)]
683 Included(RangeSyntax),
688 #[derive(Clone, Encodable, Decodable, Debug)]
689 pub enum RangeSyntax {
696 /// All the different flavors of pattern that Rust recognizes.
697 #[derive(Clone, Encodable, Decodable, Debug)]
699 /// Represents a wildcard pattern (`_`).
702 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
703 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
704 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
705 /// during name resolution.
706 Ident(BindingMode, Ident, Option<P<Pat>>),
708 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
709 /// The `bool` is `true` in the presence of a `..`.
710 Struct(Option<QSelf>, Path, Vec<PatField>, /* recovered */ bool),
712 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
713 TupleStruct(Option<QSelf>, Path, Vec<P<Pat>>),
715 /// An or-pattern `A | B | C`.
716 /// Invariant: `pats.len() >= 2`.
719 /// A possibly qualified path pattern.
720 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
721 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
722 /// only legally refer to associated constants.
723 Path(Option<QSelf>, Path),
725 /// A tuple pattern (`(a, b)`).
731 /// A reference pattern (e.g., `&mut (a, b)`).
732 Ref(P<Pat>, Mutability),
737 /// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
738 Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
740 /// A slice pattern `[a, b, c]`.
743 /// A rest pattern `..`.
745 /// Syntactically it is valid anywhere.
747 /// Semantically however, it only has meaning immediately inside:
748 /// - a slice pattern: `[a, .., b]`,
749 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
750 /// - a tuple pattern: `(a, .., b)`,
751 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
753 /// In all of these cases, an additional restriction applies,
754 /// only one rest pattern may occur in the pattern sequences.
757 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
760 /// A macro pattern; pre-expansion.
764 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
765 #[derive(HashStable_Generic, Encodable, Decodable)]
766 pub enum Mutability {
772 pub fn invert(self) -> Self {
774 Mutability::Mut => Mutability::Not,
775 Mutability::Not => Mutability::Mut,
779 pub fn prefix_str(&self) -> &'static str {
781 Mutability::Mut => "mut ",
782 Mutability::Not => "",
787 /// The kind of borrow in an `AddrOf` expression,
788 /// e.g., `&place` or `&raw const place`.
789 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
790 #[derive(Encodable, Decodable, HashStable_Generic)]
791 pub enum BorrowKind {
792 /// A normal borrow, `&$expr` or `&mut $expr`.
793 /// The resulting type is either `&'a T` or `&'a mut T`
794 /// where `T = typeof($expr)` and `'a` is some lifetime.
796 /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
797 /// The resulting type is either `*const T` or `*mut T`
798 /// where `T = typeof($expr)`.
802 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
804 /// The `+` operator (addition)
806 /// The `-` operator (subtraction)
808 /// The `*` operator (multiplication)
810 /// The `/` operator (division)
812 /// The `%` operator (modulus)
814 /// The `&&` operator (logical and)
816 /// The `||` operator (logical or)
818 /// The `^` operator (bitwise xor)
820 /// The `&` operator (bitwise and)
822 /// The `|` operator (bitwise or)
824 /// The `<<` operator (shift left)
826 /// The `>>` operator (shift right)
828 /// The `==` operator (equality)
830 /// The `<` operator (less than)
832 /// The `<=` operator (less than or equal to)
834 /// The `!=` operator (not equal to)
836 /// The `>=` operator (greater than or equal to)
838 /// The `>` operator (greater than)
843 pub fn to_string(&self) -> &'static str {
866 pub fn lazy(&self) -> bool {
867 matches!(self, BinOpKind::And | BinOpKind::Or)
870 pub fn is_comparison(&self) -> bool {
872 // Note for developers: please keep this as is;
873 // we want compilation to fail if another variant is added.
875 Eq | Lt | Le | Ne | Gt | Ge => true,
876 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
881 pub type BinOp = Spanned<BinOpKind>;
885 /// Note that `&data` is not an operator, it's an `AddrOf` expression.
886 #[derive(Clone, Encodable, Decodable, Debug, Copy)]
888 /// The `*` operator for dereferencing
890 /// The `!` operator for logical inversion
892 /// The `-` operator for negation
897 pub fn to_string(op: UnOp) -> &'static str {
907 #[derive(Clone, Encodable, Decodable, Debug)]
915 pub fn tokens(&self) -> Option<&LazyTokenStream> {
917 StmtKind::Local(ref local) => local.tokens.as_ref(),
918 StmtKind::Item(ref item) => item.tokens.as_ref(),
919 StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => expr.tokens.as_ref(),
920 StmtKind::Empty => None,
921 StmtKind::MacCall(ref mac) => mac.tokens.as_ref(),
925 pub fn has_trailing_semicolon(&self) -> bool {
927 StmtKind::Semi(_) => true,
928 StmtKind::MacCall(mac) => matches!(mac.style, MacStmtStyle::Semicolon),
933 /// Converts a parsed `Stmt` to a `Stmt` with
934 /// a trailing semicolon.
936 /// This only modifies the parsed AST struct, not the attached
937 /// `LazyTokenStream`. The parser is responsible for calling
938 /// `CreateTokenStream::add_trailing_semi` when there is actually
939 /// a semicolon in the tokenstream.
940 pub fn add_trailing_semicolon(mut self) -> Self {
941 self.kind = match self.kind {
942 StmtKind::Expr(expr) => StmtKind::Semi(expr),
943 StmtKind::MacCall(mac) => {
944 StmtKind::MacCall(mac.map(|MacCallStmt { mac, style: _, attrs, tokens }| {
945 MacCallStmt { mac, style: MacStmtStyle::Semicolon, attrs, tokens }
954 pub fn is_item(&self) -> bool {
955 matches!(self.kind, StmtKind::Item(_))
958 pub fn is_expr(&self) -> bool {
959 matches!(self.kind, StmtKind::Expr(_))
963 #[derive(Clone, Encodable, Decodable, Debug)]
965 /// A local (let) binding.
967 /// An item definition.
969 /// Expr without trailing semi-colon.
971 /// Expr with a trailing semi-colon.
973 /// Just a trailing semi-colon.
976 MacCall(P<MacCallStmt>),
979 #[derive(Clone, Encodable, Decodable, Debug)]
980 pub struct MacCallStmt {
982 pub style: MacStmtStyle,
984 pub tokens: Option<LazyTokenStream>,
987 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
988 pub enum MacStmtStyle {
989 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
990 /// `foo!(...);`, `foo![...];`).
992 /// The macro statement had braces (e.g., `foo! { ... }`).
994 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
995 /// `foo!(...)`). All of these will end up being converted into macro
1000 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
1001 #[derive(Clone, Encodable, Decodable, Debug)]
1005 pub ty: Option<P<Ty>>,
1006 /// Initializer expression to set the value, if any.
1007 pub init: Option<P<Expr>>,
1010 pub tokens: Option<LazyTokenStream>,
1013 /// An arm of a 'match'.
1015 /// E.g., `0..=10 => { println!("match!") }` as in
1019 /// 0..=10 => { println!("match!") },
1020 /// _ => { println!("no match!") },
1023 #[derive(Clone, Encodable, Decodable, Debug)]
1026 /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
1028 /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
1029 pub guard: Option<P<Expr>>,
1034 pub is_placeholder: bool,
1037 /// A single field in a struct expression, e.g. `x: value` and `y` in `Foo { x: value, y }`.
1038 #[derive(Clone, Encodable, Decodable, Debug)]
1039 pub struct ExprField {
1045 pub is_shorthand: bool,
1046 pub is_placeholder: bool,
1049 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1050 pub enum BlockCheckMode {
1052 Unsafe(UnsafeSource),
1055 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
1056 pub enum UnsafeSource {
1061 /// A constant (expression) that's not an item or associated item,
1062 /// but needs its own `DefId` for type-checking, const-eval, etc.
1063 /// These are usually found nested inside types (e.g., array lengths)
1064 /// or expressions (e.g., repeat counts), and also used to define
1065 /// explicit discriminant values for enum variants.
1066 #[derive(Clone, Encodable, Decodable, Debug)]
1067 pub struct AnonConst {
1073 #[derive(Clone, Encodable, Decodable, Debug)]
1079 pub tokens: Option<LazyTokenStream>,
1082 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
1083 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
1084 rustc_data_structures::static_assert_size!(Expr, 104);
1087 /// Returns `true` if this expression would be valid somewhere that expects a value;
1088 /// for example, an `if` condition.
1089 pub fn returns(&self) -> bool {
1090 if let ExprKind::Block(ref block, _) = self.kind {
1091 match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
1093 Some(StmtKind::Expr(_)) => true,
1094 // Last statement is an explicit return?
1095 Some(StmtKind::Semi(expr)) => matches!(expr.kind, ExprKind::Ret(_)),
1096 // This is a block that doesn't end in either an implicit or explicit return.
1100 // This is not a block, it is a value.
1105 /// Is this expr either `N`, or `{ N }`.
1107 /// If this is not the case, name resolution does not resolve `N` when using
1108 /// `min_const_generics` as more complex expressions are not supported.
1109 pub fn is_potential_trivial_const_param(&self) -> bool {
1110 let this = if let ExprKind::Block(ref block, None) = self.kind {
1111 if block.stmts.len() == 1 {
1112 if let StmtKind::Expr(ref expr) = block.stmts[0].kind { expr } else { self }
1120 if let ExprKind::Path(None, ref path) = this.kind {
1121 if path.segments.len() == 1 && path.segments[0].args.is_none() {
1129 pub fn to_bound(&self) -> Option<GenericBound> {
1131 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1132 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1133 TraitBoundModifier::None,
1139 pub fn peel_parens(&self) -> &Expr {
1140 let mut expr = self;
1141 while let ExprKind::Paren(inner) = &expr.kind {
1147 /// Attempts to reparse as `Ty` (for diagnostic purposes).
1148 pub fn to_ty(&self) -> Option<P<Ty>> {
1149 let kind = match &self.kind {
1150 // Trivial conversions.
1151 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1152 ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
1154 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1156 ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
1157 expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
1160 ExprKind::Repeat(expr, expr_len) => {
1161 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1164 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1166 ExprKind::Tup(exprs) => {
1167 let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
1171 // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
1172 // then type of result is trait object.
1173 // Otherwise we don't assume the result type.
1174 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1175 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1176 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1182 // This expression doesn't look like a type syntactically.
1186 Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
1189 pub fn precedence(&self) -> ExprPrecedence {
1191 ExprKind::Box(_) => ExprPrecedence::Box,
1192 ExprKind::Array(_) => ExprPrecedence::Array,
1193 ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
1194 ExprKind::Call(..) => ExprPrecedence::Call,
1195 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1196 ExprKind::Tup(_) => ExprPrecedence::Tup,
1197 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1198 ExprKind::Unary(..) => ExprPrecedence::Unary,
1199 ExprKind::Lit(_) => ExprPrecedence::Lit,
1200 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1201 ExprKind::Let(..) => ExprPrecedence::Let,
1202 ExprKind::If(..) => ExprPrecedence::If,
1203 ExprKind::While(..) => ExprPrecedence::While,
1204 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1205 ExprKind::Loop(..) => ExprPrecedence::Loop,
1206 ExprKind::Match(..) => ExprPrecedence::Match,
1207 ExprKind::Closure(..) => ExprPrecedence::Closure,
1208 ExprKind::Block(..) => ExprPrecedence::Block,
1209 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1210 ExprKind::Async(..) => ExprPrecedence::Async,
1211 ExprKind::Await(..) => ExprPrecedence::Await,
1212 ExprKind::Assign(..) => ExprPrecedence::Assign,
1213 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1214 ExprKind::Field(..) => ExprPrecedence::Field,
1215 ExprKind::Index(..) => ExprPrecedence::Index,
1216 ExprKind::Range(..) => ExprPrecedence::Range,
1217 ExprKind::Underscore => ExprPrecedence::Path,
1218 ExprKind::Path(..) => ExprPrecedence::Path,
1219 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1220 ExprKind::Break(..) => ExprPrecedence::Break,
1221 ExprKind::Continue(..) => ExprPrecedence::Continue,
1222 ExprKind::Ret(..) => ExprPrecedence::Ret,
1223 ExprKind::InlineAsm(..) | ExprKind::LlvmInlineAsm(..) => ExprPrecedence::InlineAsm,
1224 ExprKind::MacCall(..) => ExprPrecedence::Mac,
1225 ExprKind::Struct(..) => ExprPrecedence::Struct,
1226 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1227 ExprKind::Paren(..) => ExprPrecedence::Paren,
1228 ExprKind::Try(..) => ExprPrecedence::Try,
1229 ExprKind::Yield(..) => ExprPrecedence::Yield,
1230 ExprKind::Err => ExprPrecedence::Err,
1235 /// Limit types of a range (inclusive or exclusive)
1236 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
1237 pub enum RangeLimits {
1238 /// Inclusive at the beginning, exclusive at the end
1240 /// Inclusive at the beginning and end
1244 #[derive(Clone, Encodable, Decodable, Debug)]
1245 pub enum StructRest {
1250 /// No trailing `..` or expression.
1254 #[derive(Clone, Encodable, Decodable, Debug)]
1255 pub struct StructExpr {
1256 pub qself: Option<QSelf>,
1258 pub fields: Vec<ExprField>,
1259 pub rest: StructRest,
1262 #[derive(Clone, Encodable, Decodable, Debug)]
1264 /// A `box x` expression.
1266 /// An array (`[a, b, c, d]`)
1267 Array(Vec<P<Expr>>),
1268 /// Allow anonymous constants from an inline `const` block
1269 ConstBlock(AnonConst),
1272 /// The first field resolves to the function itself,
1273 /// and the second field is the list of arguments.
1274 /// This also represents calling the constructor of
1275 /// tuple-like ADTs such as tuple structs and enum variants.
1276 Call(P<Expr>, Vec<P<Expr>>),
1277 /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1279 /// The `PathSegment` represents the method name and its generic arguments
1280 /// (within the angle brackets).
1281 /// The first element of the vector of an `Expr` is the expression that evaluates
1282 /// to the object on which the method is being called on (the receiver),
1283 /// and the remaining elements are the rest of the arguments.
1284 /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1285 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
1286 /// This `Span` is the span of the function, without the dot and receiver
1287 /// (e.g. `foo(a, b)` in `x.foo(a, b)`
1288 MethodCall(PathSegment, Vec<P<Expr>>, Span),
1289 /// A tuple (e.g., `(a, b, c, d)`).
1291 /// A binary operation (e.g., `a + b`, `a * b`).
1292 Binary(BinOp, P<Expr>, P<Expr>),
1293 /// A unary operation (e.g., `!x`, `*x`).
1294 Unary(UnOp, P<Expr>),
1295 /// A literal (e.g., `1`, `"foo"`).
1297 /// A cast (e.g., `foo as f64`).
1298 Cast(P<Expr>, P<Ty>),
1299 /// A type ascription (e.g., `42: usize`).
1300 Type(P<Expr>, P<Ty>),
1301 /// A `let pat = expr` expression that is only semantically allowed in the condition
1302 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1303 Let(P<Pat>, P<Expr>),
1304 /// An `if` block, with an optional `else` block.
1306 /// `if expr { block } else { expr }`
1307 If(P<Expr>, P<Block>, Option<P<Expr>>),
1308 /// A while loop, with an optional label.
1310 /// `'label: while expr { block }`
1311 While(P<Expr>, P<Block>, Option<Label>),
1312 /// A `for` loop, with an optional label.
1314 /// `'label: for pat in expr { block }`
1316 /// This is desugared to a combination of `loop` and `match` expressions.
1317 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1318 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1320 /// `'label: loop { block }`
1321 Loop(P<Block>, Option<Label>),
1322 /// A `match` block.
1323 Match(P<Expr>, Vec<Arm>),
1324 /// A closure (e.g., `move |a, b, c| a + b + c`).
1326 /// The final span is the span of the argument block `|...|`.
1327 Closure(CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
1328 /// A block (`'label: { ... }`).
1329 Block(P<Block>, Option<Label>),
1330 /// An async block (`async move { ... }`).
1332 /// The `NodeId` is the `NodeId` for the closure that results from
1333 /// desugaring an async block, just like the NodeId field in the
1334 /// `Async::Yes` variant. This is necessary in order to create a def for the
1335 /// closure which can be used as a parent of any child defs. Defs
1336 /// created during lowering cannot be made the parent of any other
1337 /// preexisting defs.
1338 Async(CaptureBy, NodeId, P<Block>),
1339 /// An await expression (`my_future.await`).
1342 /// A try block (`try { ... }`).
1345 /// An assignment (`a = foo()`).
1346 /// The `Span` argument is the span of the `=` token.
1347 Assign(P<Expr>, P<Expr>, Span),
1348 /// An assignment with an operator.
1351 AssignOp(BinOp, P<Expr>, P<Expr>),
1352 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1353 Field(P<Expr>, Ident),
1354 /// An indexing operation (e.g., `foo[2]`).
1355 Index(P<Expr>, P<Expr>),
1356 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assignment).
1357 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1358 /// An underscore, used in destructuring assignment to ignore a value.
1361 /// Variable reference, possibly containing `::` and/or type
1362 /// parameters (e.g., `foo::bar::<baz>`).
1364 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1365 Path(Option<QSelf>, Path),
1367 /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
1368 AddrOf(BorrowKind, Mutability, P<Expr>),
1369 /// A `break`, with an optional label to break, and an optional expression.
1370 Break(Option<Label>, Option<P<Expr>>),
1371 /// A `continue`, with an optional label.
1372 Continue(Option<Label>),
1373 /// A `return`, with an optional value to be returned.
1374 Ret(Option<P<Expr>>),
1376 /// Output of the `asm!()` macro.
1377 InlineAsm(P<InlineAsm>),
1378 /// Output of the `llvm_asm!()` macro.
1379 LlvmInlineAsm(P<LlvmInlineAsm>),
1381 /// A macro invocation; pre-expansion.
1384 /// A struct literal expression.
1386 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
1387 Struct(P<StructExpr>),
1389 /// An array literal constructed from one repeated element.
1391 /// E.g., `[1; 5]`. The expression is the element to be
1392 /// repeated; the constant is the number of times to repeat it.
1393 Repeat(P<Expr>, AnonConst),
1395 /// No-op: used solely so we can pretty-print faithfully.
1398 /// A try expression (`expr?`).
1401 /// A `yield`, with an optional value to be yielded.
1402 Yield(Option<P<Expr>>),
1404 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1408 /// The explicit `Self` type in a "qualified path". The actual
1409 /// path, including the trait and the associated item, is stored
1410 /// separately. `position` represents the index of the associated
1411 /// item qualified with this `Self` type.
1413 /// ```ignore (only-for-syntax-highlight)
1414 /// <Vec<T> as a::b::Trait>::AssociatedItem
1415 /// ^~~~~ ~~~~~~~~~~~~~~^
1418 /// <Vec<T>>::AssociatedItem
1422 #[derive(Clone, Encodable, Decodable, Debug)]
1426 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1427 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1428 /// 0`, this is an empty span.
1429 pub path_span: Span,
1430 pub position: usize,
1433 /// A capture clause used in closures and `async` blocks.
1434 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1435 pub enum CaptureBy {
1436 /// `move |x| y + x`.
1438 /// `move` keyword was not specified.
1442 /// The movability of a generator / closure literal:
1443 /// whether a generator contains self-references, causing it to be `!Unpin`.
1444 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
1445 #[derive(HashStable_Generic)]
1446 pub enum Movability {
1447 /// May contain self-references, `!Unpin`.
1449 /// Must not contain self-references, `Unpin`.
1453 /// Represents a macro invocation. The `path` indicates which macro
1454 /// is being invoked, and the `args` are arguments passed to it.
1455 #[derive(Clone, Encodable, Decodable, Debug)]
1456 pub struct MacCall {
1458 pub args: P<MacArgs>,
1459 pub prior_type_ascription: Option<(Span, bool)>,
1463 pub fn span(&self) -> Span {
1464 self.path.span.to(self.args.span().unwrap_or(self.path.span))
1468 /// Arguments passed to an attribute or a function-like macro.
1469 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1471 /// No arguments - `#[attr]`.
1473 /// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
1474 Delimited(DelimSpan, MacDelimiter, TokenStream),
1475 /// Arguments of a key-value attribute - `#[attr = "value"]`.
1477 /// Span of the `=` token.
1479 /// "value" as a nonterminal token.
1485 pub fn delim(&self) -> DelimToken {
1487 MacArgs::Delimited(_, delim, _) => delim.to_token(),
1488 MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
1492 pub fn span(&self) -> Option<Span> {
1494 MacArgs::Empty => None,
1495 MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
1496 MacArgs::Eq(eq_span, token) => Some(eq_span.to(token.span)),
1500 /// Tokens inside the delimiters or after `=`.
1501 /// Proc macros see these tokens, for example.
1502 pub fn inner_tokens(&self) -> TokenStream {
1504 MacArgs::Empty => TokenStream::default(),
1505 MacArgs::Delimited(.., tokens) => tokens.clone(),
1506 MacArgs::Eq(.., token) => TokenTree::Token(token.clone()).into(),
1510 /// Whether a macro with these arguments needs a semicolon
1511 /// when used as a standalone item or statement.
1512 pub fn need_semicolon(&self) -> bool {
1513 !matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
1517 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
1518 pub enum MacDelimiter {
1525 pub fn to_token(self) -> DelimToken {
1527 MacDelimiter::Parenthesis => DelimToken::Paren,
1528 MacDelimiter::Bracket => DelimToken::Bracket,
1529 MacDelimiter::Brace => DelimToken::Brace,
1533 pub fn from_token(delim: DelimToken) -> Option<MacDelimiter> {
1535 token::Paren => Some(MacDelimiter::Parenthesis),
1536 token::Bracket => Some(MacDelimiter::Bracket),
1537 token::Brace => Some(MacDelimiter::Brace),
1538 token::NoDelim => None,
1543 /// Represents a macro definition.
1544 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1545 pub struct MacroDef {
1546 pub body: P<MacArgs>,
1547 /// `true` if macro was defined with `macro_rules`.
1548 pub macro_rules: bool,
1551 #[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
1552 #[derive(HashStable_Generic)]
1554 /// A regular string, like `"foo"`.
1556 /// A raw string, like `r##"foo"##`.
1558 /// The value is the number of `#` symbols used.
1563 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
1565 /// The original literal token as written in source code.
1566 pub token: token::Lit,
1567 /// The "semantic" representation of the literal lowered from the original tokens.
1568 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1569 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1574 /// Same as `Lit`, but restricted to string literals.
1575 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1577 /// The original literal token as written in source code.
1578 pub style: StrStyle,
1580 pub suffix: Option<Symbol>,
1582 /// The unescaped "semantic" representation of the literal lowered from the original token.
1583 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1584 pub symbol_unescaped: Symbol,
1588 pub fn as_lit(&self) -> Lit {
1589 let token_kind = match self.style {
1590 StrStyle::Cooked => token::Str,
1591 StrStyle::Raw(n) => token::StrRaw(n),
1594 token: token::Lit::new(token_kind, self.symbol, self.suffix),
1596 kind: LitKind::Str(self.symbol_unescaped, self.style),
1601 /// Type of the integer literal based on provided suffix.
1602 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1603 #[derive(HashStable_Generic)]
1604 pub enum LitIntType {
1613 /// Type of the float literal based on provided suffix.
1614 #[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
1615 #[derive(HashStable_Generic)]
1616 pub enum LitFloatType {
1617 /// A float literal with a suffix (`1f32` or `1E10f32`).
1619 /// A float literal without a suffix (`1.0 or 1.0E10`).
1625 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
1626 #[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
1628 /// A string literal (`"foo"`).
1629 Str(Symbol, StrStyle),
1630 /// A byte string (`b"foo"`).
1632 /// A byte char (`b'f'`).
1634 /// A character literal (`'a'`).
1636 /// An integer literal (`1`).
1637 Int(u128, LitIntType),
1638 /// A float literal (`1f64` or `1E10f64`).
1639 Float(Symbol, LitFloatType),
1640 /// A boolean literal.
1642 /// Placeholder for a literal that wasn't well-formed in some way.
1647 /// Returns `true` if this literal is a string.
1648 pub fn is_str(&self) -> bool {
1649 matches!(self, LitKind::Str(..))
1652 /// Returns `true` if this literal is byte literal string.
1653 pub fn is_bytestr(&self) -> bool {
1654 matches!(self, LitKind::ByteStr(_))
1657 /// Returns `true` if this is a numeric literal.
1658 pub fn is_numeric(&self) -> bool {
1659 matches!(self, LitKind::Int(..) | LitKind::Float(..))
1662 /// Returns `true` if this literal has no suffix.
1663 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1664 pub fn is_unsuffixed(&self) -> bool {
1668 /// Returns `true` if this literal has a suffix.
1669 pub fn is_suffixed(&self) -> bool {
1671 // suffixed variants
1672 LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
1673 | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
1674 // unsuffixed variants
1676 | LitKind::ByteStr(..)
1679 | LitKind::Int(_, LitIntType::Unsuffixed)
1680 | LitKind::Float(_, LitFloatType::Unsuffixed)
1682 | LitKind::Err(..) => false,
1687 // N.B., If you change this, you'll probably want to change the corresponding
1688 // type structure in `middle/ty.rs` as well.
1689 #[derive(Clone, Encodable, Decodable, Debug)]
1692 pub mutbl: Mutability,
1695 /// Represents a function's signature in a trait declaration,
1696 /// trait implementation, or free function.
1697 #[derive(Clone, Encodable, Decodable, Debug)]
1699 pub header: FnHeader,
1700 pub decl: P<FnDecl>,
1704 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1705 #[derive(Encodable, Decodable, HashStable_Generic)]
1712 pub fn name_str(self) -> &'static str {
1714 FloatTy::F32 => "f32",
1715 FloatTy::F64 => "f64",
1719 pub fn name(self) -> Symbol {
1721 FloatTy::F32 => sym::f32,
1722 FloatTy::F64 => sym::f64,
1727 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
1728 #[derive(Encodable, Decodable, HashStable_Generic)]
1739 pub fn name_str(&self) -> &'static str {
1741 IntTy::Isize => "isize",
1743 IntTy::I16 => "i16",
1744 IntTy::I32 => "i32",
1745 IntTy::I64 => "i64",
1746 IntTy::I128 => "i128",
1750 pub fn name(&self) -> Symbol {
1752 IntTy::Isize => sym::isize,
1753 IntTy::I8 => sym::i8,
1754 IntTy::I16 => sym::i16,
1755 IntTy::I32 => sym::i32,
1756 IntTy::I64 => sym::i64,
1757 IntTy::I128 => sym::i128,
1762 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
1763 #[derive(Encodable, Decodable, HashStable_Generic)]
1774 pub fn name_str(&self) -> &'static str {
1776 UintTy::Usize => "usize",
1778 UintTy::U16 => "u16",
1779 UintTy::U32 => "u32",
1780 UintTy::U64 => "u64",
1781 UintTy::U128 => "u128",
1785 pub fn name(&self) -> Symbol {
1787 UintTy::Usize => sym::usize,
1788 UintTy::U8 => sym::u8,
1789 UintTy::U16 => sym::u16,
1790 UintTy::U32 => sym::u32,
1791 UintTy::U64 => sym::u64,
1792 UintTy::U128 => sym::u128,
1797 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1798 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1799 #[derive(Clone, Encodable, Decodable, Debug)]
1800 pub struct AssocTyConstraint {
1803 pub gen_args: Option<GenericArgs>,
1804 pub kind: AssocTyConstraintKind,
1808 /// The kinds of an `AssocTyConstraint`.
1809 #[derive(Clone, Encodable, Decodable, Debug)]
1810 pub enum AssocTyConstraintKind {
1811 /// E.g., `A = Bar` in `Foo<A = Bar>`.
1812 Equality { ty: P<Ty> },
1813 /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
1814 Bound { bounds: GenericBounds },
1817 #[derive(Encodable, Decodable, Debug)]
1822 pub tokens: Option<LazyTokenStream>,
1826 fn clone(&self) -> Self {
1827 ensure_sufficient_stack(|| Self {
1829 kind: self.kind.clone(),
1831 tokens: self.tokens.clone(),
1837 pub fn peel_refs(&self) -> &Self {
1838 let mut final_ty = self;
1839 while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
1846 #[derive(Clone, Encodable, Decodable, Debug)]
1847 pub struct BareFnTy {
1848 pub unsafety: Unsafe,
1850 pub generic_params: Vec<GenericParam>,
1851 pub decl: P<FnDecl>,
1854 /// The various kinds of type recognized by the compiler.
1855 #[derive(Clone, Encodable, Decodable, Debug)]
1857 /// A variable-length slice (`[T]`).
1859 /// A fixed length array (`[T; n]`).
1860 Array(P<Ty>, AnonConst),
1861 /// A raw pointer (`*const T` or `*mut T`).
1863 /// A reference (`&'a T` or `&'a mut T`).
1864 Rptr(Option<Lifetime>, MutTy),
1865 /// A bare function (e.g., `fn(usize) -> bool`).
1866 BareFn(P<BareFnTy>),
1867 /// The never type (`!`).
1869 /// A tuple (`(A, B, C, D,...)`).
1871 /// An anonymous struct type i.e. `struct { foo: Type }`
1872 AnonymousStruct(Vec<FieldDef>, bool),
1873 /// An anonymous union type i.e. `union { bar: Type }`
1874 AnonymousUnion(Vec<FieldDef>, bool),
1875 /// A path (`module::module::...::Type`), optionally
1876 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
1878 /// Type parameters are stored in the `Path` itself.
1879 Path(Option<QSelf>, Path),
1880 /// A trait object type `Bound1 + Bound2 + Bound3`
1881 /// where `Bound` is a trait or a lifetime.
1882 TraitObject(GenericBounds, TraitObjectSyntax),
1883 /// An `impl Bound1 + Bound2 + Bound3` type
1884 /// where `Bound` is a trait or a lifetime.
1886 /// The `NodeId` exists to prevent lowering from having to
1887 /// generate `NodeId`s on the fly, which would complicate
1888 /// the generation of opaque `type Foo = impl Trait` items significantly.
1889 ImplTrait(NodeId, GenericBounds),
1890 /// No-op; kept solely so that we can pretty-print faithfully.
1894 /// This means the type should be inferred instead of it having been
1895 /// specified. This can appear anywhere in a type.
1897 /// Inferred type of a `self` or `&self` argument in a method.
1899 /// A macro in the type position.
1901 /// Placeholder for a kind that has failed to be defined.
1903 /// Placeholder for a `va_list`.
1908 pub fn is_implicit_self(&self) -> bool {
1909 matches!(self, TyKind::ImplicitSelf)
1912 pub fn is_unit(&self) -> bool {
1913 matches!(self, TyKind::Tup(tys) if tys.is_empty())
1917 /// Syntax used to declare a trait object.
1918 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
1919 pub enum TraitObjectSyntax {
1924 /// Inline assembly operand explicit register or register class.
1926 /// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
1927 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
1928 pub enum InlineAsmRegOrRegClass {
1933 bitflags::bitflags! {
1934 #[derive(Encodable, Decodable, HashStable_Generic)]
1935 pub struct InlineAsmOptions: u8 {
1936 const PURE = 1 << 0;
1937 const NOMEM = 1 << 1;
1938 const READONLY = 1 << 2;
1939 const PRESERVES_FLAGS = 1 << 3;
1940 const NORETURN = 1 << 4;
1941 const NOSTACK = 1 << 5;
1942 const ATT_SYNTAX = 1 << 6;
1947 #[derive(Clone, PartialEq, PartialOrd, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
1948 pub enum InlineAsmTemplatePiece {
1950 Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
1953 impl fmt::Display for InlineAsmTemplatePiece {
1954 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1956 Self::String(s) => {
1957 for c in s.chars() {
1959 '{' => f.write_str("{{")?,
1960 '}' => f.write_str("}}")?,
1966 Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
1967 write!(f, "{{{}:{}}}", operand_idx, modifier)
1969 Self::Placeholder { operand_idx, modifier: None, .. } => {
1970 write!(f, "{{{}}}", operand_idx)
1976 impl InlineAsmTemplatePiece {
1977 /// Rebuilds the asm template string from its pieces.
1978 pub fn to_string(s: &[Self]) -> String {
1980 let mut out = String::new();
1982 let _ = write!(out, "{}", p);
1988 /// Inline assembly operand.
1990 /// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
1991 #[derive(Clone, Encodable, Decodable, Debug)]
1992 pub enum InlineAsmOperand {
1994 reg: InlineAsmRegOrRegClass,
1998 reg: InlineAsmRegOrRegClass,
2000 expr: Option<P<Expr>>,
2003 reg: InlineAsmRegOrRegClass,
2008 reg: InlineAsmRegOrRegClass,
2011 out_expr: Option<P<Expr>>,
2014 anon_const: AnonConst,
2021 /// Inline assembly.
2023 /// E.g., `asm!("NOP");`.
2024 #[derive(Clone, Encodable, Decodable, Debug)]
2025 pub struct InlineAsm {
2026 pub template: Vec<InlineAsmTemplatePiece>,
2027 pub operands: Vec<(InlineAsmOperand, Span)>,
2028 pub options: InlineAsmOptions,
2029 pub line_spans: Vec<Span>,
2032 /// Inline assembly dialect.
2034 /// E.g., `"intel"` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2035 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, Hash, HashStable_Generic)]
2036 pub enum LlvmAsmDialect {
2041 /// LLVM-style inline assembly.
2043 /// E.g., `"={eax}"(result)` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
2044 #[derive(Clone, Encodable, Decodable, Debug)]
2045 pub struct LlvmInlineAsmOutput {
2046 pub constraint: Symbol,
2049 pub is_indirect: bool,
2052 /// LLVM-style inline assembly.
2054 /// E.g., `llvm_asm!("NOP");`.
2055 #[derive(Clone, Encodable, Decodable, Debug)]
2056 pub struct LlvmInlineAsm {
2058 pub asm_str_style: StrStyle,
2059 pub outputs: Vec<LlvmInlineAsmOutput>,
2060 pub inputs: Vec<(Symbol, P<Expr>)>,
2061 pub clobbers: Vec<Symbol>,
2063 pub alignstack: bool,
2064 pub dialect: LlvmAsmDialect,
2067 /// A parameter in a function header.
2069 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
2070 #[derive(Clone, Encodable, Decodable, Debug)]
2077 pub is_placeholder: bool,
2080 /// Alternative representation for `Arg`s describing `self` parameter of methods.
2082 /// E.g., `&mut self` as in `fn foo(&mut self)`.
2083 #[derive(Clone, Encodable, Decodable, Debug)]
2085 /// `self`, `mut self`
2087 /// `&'lt self`, `&'lt mut self`
2088 Region(Option<Lifetime>, Mutability),
2089 /// `self: TYPE`, `mut self: TYPE`
2090 Explicit(P<Ty>, Mutability),
2093 pub type ExplicitSelf = Spanned<SelfKind>;
2096 /// Attempts to cast parameter to `ExplicitSelf`.
2097 pub fn to_self(&self) -> Option<ExplicitSelf> {
2098 if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
2099 if ident.name == kw::SelfLower {
2100 return match self.ty.kind {
2101 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
2102 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
2103 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
2106 self.pat.span.to(self.ty.span),
2107 SelfKind::Explicit(self.ty.clone(), mutbl),
2115 /// Returns `true` if parameter is `self`.
2116 pub fn is_self(&self) -> bool {
2117 if let PatKind::Ident(_, ident, _) = self.pat.kind {
2118 ident.name == kw::SelfLower
2124 /// Builds a `Param` object from `ExplicitSelf`.
2125 pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
2126 let span = eself.span.to(eself_ident.span);
2127 let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
2128 let param = |mutbl, ty| Param {
2132 kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
2139 is_placeholder: false,
2142 SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
2143 SelfKind::Value(mutbl) => param(mutbl, infer_ty),
2144 SelfKind::Region(lt, mutbl) => param(
2148 kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
2157 /// A signature (not the body) of a function declaration.
2159 /// E.g., `fn foo(bar: baz)`.
2161 /// Please note that it's different from `FnHeader` structure
2162 /// which contains metadata about function safety, asyncness, constness and ABI.
2163 #[derive(Clone, Encodable, Decodable, Debug)]
2165 pub inputs: Vec<Param>,
2166 pub output: FnRetTy,
2170 pub fn has_self(&self) -> bool {
2171 self.inputs.get(0).map_or(false, Param::is_self)
2173 pub fn c_variadic(&self) -> bool {
2174 self.inputs.last().map_or(false, |arg| matches!(arg.ty.kind, TyKind::CVarArgs))
2178 /// Is the trait definition an auto trait?
2179 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2185 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug)]
2186 #[derive(HashStable_Generic)]
2192 #[derive(Copy, Clone, Encodable, Decodable, Debug)]
2194 Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
2199 pub fn is_async(self) -> bool {
2200 matches!(self, Async::Yes { .. })
2203 /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
2204 pub fn opt_return_id(self) -> Option<NodeId> {
2206 Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
2212 #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
2213 #[derive(HashStable_Generic)]
2219 /// Item defaultness.
2220 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
2221 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
2222 pub enum Defaultness {
2227 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
2228 pub enum ImplPolarity {
2229 /// `impl Trait for Type`
2231 /// `impl !Trait for Type`
2235 impl fmt::Debug for ImplPolarity {
2236 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2238 ImplPolarity::Positive => "positive".fmt(f),
2239 ImplPolarity::Negative(_) => "negative".fmt(f),
2244 #[derive(Clone, Encodable, Decodable, Debug)]
2246 /// Returns type is not specified.
2248 /// Functions default to `()` and closures default to inference.
2249 /// Span points to where return type would be inserted.
2251 /// Everything else.
2256 pub fn span(&self) -> Span {
2258 FnRetTy::Default(span) => span,
2259 FnRetTy::Ty(ref ty) => ty.span,
2264 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
2270 /// Module item kind.
2271 #[derive(Clone, Encodable, Decodable, Debug)]
2273 /// Module with inlined definition `mod foo { ... }`,
2274 /// or with definition outlined to a separate file `mod foo;` and already loaded from it.
2275 /// The inner span is from the first token past `{` to the last token until `}`,
2276 /// or from the first to the last token in the loaded file.
2277 Loaded(Vec<P<Item>>, Inline, Span),
2278 /// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
2282 /// Foreign module declaration.
2284 /// E.g., `extern { .. }` or `extern "C" { .. }`.
2285 #[derive(Clone, Encodable, Decodable, Debug)]
2286 pub struct ForeignMod {
2287 /// `unsafe` keyword accepted syntactically for macro DSLs, but not
2288 /// semantically by Rust.
2289 pub unsafety: Unsafe,
2290 pub abi: Option<StrLit>,
2291 pub items: Vec<P<ForeignItem>>,
2294 #[derive(Clone, Encodable, Decodable, Debug)]
2295 pub struct EnumDef {
2296 pub variants: Vec<Variant>,
2299 #[derive(Clone, Encodable, Decodable, Debug)]
2300 pub struct Variant {
2301 /// Attributes of the variant.
2303 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2307 /// The visibility of the variant. Syntactically accepted but not semantically.
2308 pub vis: Visibility,
2309 /// Name of the variant.
2312 /// Fields and constructor id of the variant.
2313 pub data: VariantData,
2314 /// Explicit discriminant, e.g., `Foo = 1`.
2315 pub disr_expr: Option<AnonConst>,
2316 /// Is a macro placeholder
2317 pub is_placeholder: bool,
2320 /// Part of `use` item to the right of its prefix.
2321 #[derive(Clone, Encodable, Decodable, Debug)]
2322 pub enum UseTreeKind {
2323 /// `use prefix` or `use prefix as rename`
2325 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2327 Simple(Option<Ident>, NodeId, NodeId),
2328 /// `use prefix::{...}`
2329 Nested(Vec<(UseTree, NodeId)>),
2334 /// A tree of paths sharing common prefixes.
2335 /// Used in `use` items both at top-level and inside of braces in import groups.
2336 #[derive(Clone, Encodable, Decodable, Debug)]
2337 pub struct UseTree {
2339 pub kind: UseTreeKind,
2344 pub fn ident(&self) -> Ident {
2346 UseTreeKind::Simple(Some(rename), ..) => rename,
2347 UseTreeKind::Simple(None, ..) => {
2348 self.prefix.segments.last().expect("empty prefix in a simple import").ident
2350 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2355 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2356 /// are contained as statements within items. These two cases need to be
2357 /// distinguished for pretty-printing.
2358 #[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
2359 pub enum AttrStyle {
2364 rustc_index::newtype_index! {
2367 DEBUG_FORMAT = "AttrId({})"
2371 impl<S: Encoder> rustc_serialize::Encodable<S> for AttrId {
2372 fn encode(&self, s: &mut S) -> Result<(), S::Error> {
2377 impl<D: Decoder> rustc_serialize::Decodable<D> for AttrId {
2378 fn decode(d: &mut D) -> Result<AttrId, D::Error> {
2379 d.read_nil().map(|_| crate::attr::mk_attr_id())
2383 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2384 pub struct AttrItem {
2387 pub tokens: Option<LazyTokenStream>,
2390 /// A list of attributes.
2391 pub type AttrVec = ThinVec<Attribute>;
2393 /// Metadata associated with an item.
2394 #[derive(Clone, Encodable, Decodable, Debug)]
2395 pub struct Attribute {
2398 /// Denotes if the attribute decorates the following construct (outer)
2399 /// or the construct this attribute is contained within (inner).
2400 pub style: AttrStyle,
2404 #[derive(Clone, Encodable, Decodable, Debug)]
2406 /// A normal attribute.
2407 Normal(AttrItem, Option<LazyTokenStream>),
2409 /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
2410 /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
2411 /// variant (which is much less compact and thus more expensive).
2412 DocComment(CommentKind, Symbol),
2415 /// `TraitRef`s appear in impls.
2417 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2418 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2419 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2420 /// same as the impl's `NodeId`).
2421 #[derive(Clone, Encodable, Decodable, Debug)]
2422 pub struct TraitRef {
2427 #[derive(Clone, Encodable, Decodable, Debug)]
2428 pub struct PolyTraitRef {
2429 /// The `'a` in `<'a> Foo<&'a T>`.
2430 pub bound_generic_params: Vec<GenericParam>,
2432 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2433 pub trait_ref: TraitRef,
2439 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2441 bound_generic_params: generic_params,
2442 trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
2448 #[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)]
2449 pub enum CrateSugar {
2450 /// Source is `pub(crate)`.
2453 /// Source is (just) `crate`.
2457 #[derive(Clone, Encodable, Decodable, Debug)]
2458 pub struct Visibility {
2459 pub kind: VisibilityKind,
2461 pub tokens: Option<LazyTokenStream>,
2464 #[derive(Clone, Encodable, Decodable, Debug)]
2465 pub enum VisibilityKind {
2468 Restricted { path: P<Path>, id: NodeId },
2472 impl VisibilityKind {
2473 pub fn is_pub(&self) -> bool {
2474 matches!(self, VisibilityKind::Public)
2478 /// Field definition in a struct, variant or union.
2480 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2481 #[derive(Clone, Encodable, Decodable, Debug)]
2482 pub struct FieldDef {
2486 pub vis: Visibility,
2487 pub ident: Option<Ident>,
2490 pub is_placeholder: bool,
2493 /// Fields and constructor ids of enum variants and structs.
2494 #[derive(Clone, Encodable, Decodable, Debug)]
2495 pub enum VariantData {
2498 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2499 Struct(Vec<FieldDef>, bool),
2502 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2503 Tuple(Vec<FieldDef>, NodeId),
2506 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2511 /// Return the fields of this variant.
2512 pub fn fields(&self) -> &[FieldDef] {
2514 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
2519 /// Return the `NodeId` of this variant's constructor, if it has one.
2520 pub fn ctor_id(&self) -> Option<NodeId> {
2522 VariantData::Struct(..) => None,
2523 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2528 /// An item definition.
2529 #[derive(Clone, Encodable, Decodable, Debug)]
2530 pub struct Item<K = ItemKind> {
2531 pub attrs: Vec<Attribute>,
2534 pub vis: Visibility,
2535 /// The name of the item.
2536 /// It might be a dummy name in case of anonymous items.
2541 /// Original tokens this item was parsed from. This isn't necessarily
2542 /// available for all items, although over time more and more items should
2543 /// have this be `Some`. Right now this is primarily used for procedural
2544 /// macros, notably custom attributes.
2546 /// Note that the tokens here do not include the outer attributes, but will
2547 /// include inner attributes.
2548 pub tokens: Option<LazyTokenStream>,
2552 /// Return the span that encompasses the attributes.
2553 pub fn span_with_attributes(&self) -> Span {
2554 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2558 impl<K: Into<ItemKind>> Item<K> {
2559 pub fn into_item(self) -> Item {
2560 let Item { attrs, id, span, vis, ident, kind, tokens } = self;
2561 Item { attrs, id, span, vis, ident, kind: kind.into(), tokens }
2565 /// `extern` qualifier on a function item or function type.
2566 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2574 pub fn from_abi(abi: Option<StrLit>) -> Extern {
2575 abi.map_or(Extern::Implicit, Extern::Explicit)
2579 /// A function header.
2581 /// All the information between the visibility and the name of the function is
2582 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2583 #[derive(Clone, Copy, Encodable, Decodable, Debug)]
2584 pub struct FnHeader {
2585 pub unsafety: Unsafe,
2586 pub asyncness: Async,
2587 pub constness: Const,
2592 /// Does this function header have any qualifiers or is it empty?
2593 pub fn has_qualifiers(&self) -> bool {
2594 let Self { unsafety, asyncness, constness, ext } = self;
2595 matches!(unsafety, Unsafe::Yes(_))
2596 || asyncness.is_async()
2597 || matches!(constness, Const::Yes(_))
2598 || !matches!(ext, Extern::None)
2602 impl Default for FnHeader {
2603 fn default() -> FnHeader {
2605 unsafety: Unsafe::No,
2606 asyncness: Async::No,
2607 constness: Const::No,
2613 #[derive(Clone, Encodable, Decodable, Debug)]
2614 pub struct TraitKind(
2619 pub Vec<P<AssocItem>>,
2622 #[derive(Clone, Encodable, Decodable, Debug)]
2623 pub struct TyAliasKind(pub Defaultness, pub Generics, pub GenericBounds, pub Option<P<Ty>>);
2625 #[derive(Clone, Encodable, Decodable, Debug)]
2626 pub struct ImplKind {
2627 pub unsafety: Unsafe,
2628 pub polarity: ImplPolarity,
2629 pub defaultness: Defaultness,
2630 pub constness: Const,
2631 pub generics: Generics,
2633 /// The trait being implemented, if any.
2634 pub of_trait: Option<TraitRef>,
2637 pub items: Vec<P<AssocItem>>,
2640 #[derive(Clone, Encodable, Decodable, Debug)]
2641 pub struct FnKind(pub Defaultness, pub FnSig, pub Generics, pub Option<P<Block>>);
2643 #[derive(Clone, Encodable, Decodable, Debug)]
2645 /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
2647 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2648 ExternCrate(Option<Symbol>),
2649 /// A use declaration item (`use`).
2651 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2653 /// A static item (`static`).
2655 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2656 Static(P<Ty>, Mutability, Option<P<Expr>>),
2657 /// A constant item (`const`).
2659 /// E.g., `const FOO: i32 = 42;`.
2660 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2661 /// A function declaration (`fn`).
2663 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2665 /// A module declaration (`mod`).
2667 /// E.g., `mod foo;` or `mod foo { .. }`.
2668 /// `unsafe` keyword on modules is accepted syntactically for macro DSLs, but not
2669 /// semantically by Rust.
2670 Mod(Unsafe, ModKind),
2671 /// An external module (`extern`).
2673 /// E.g., `extern {}` or `extern "C" {}`.
2674 ForeignMod(ForeignMod),
2675 /// Module-level inline assembly (from `global_asm!()`).
2676 GlobalAsm(InlineAsm),
2677 /// A type alias (`type`).
2679 /// E.g., `type Foo = Bar<u8>;`.
2680 TyAlias(Box<TyAliasKind>),
2681 /// An enum definition (`enum`).
2683 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2684 Enum(EnumDef, Generics),
2685 /// A struct definition (`struct`).
2687 /// E.g., `struct Foo<A> { x: A }`.
2688 Struct(VariantData, Generics),
2689 /// A union definition (`union`).
2691 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2692 Union(VariantData, Generics),
2693 /// A trait declaration (`trait`).
2695 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2696 Trait(Box<TraitKind>),
2699 /// E.g., `trait Foo = Bar + Quux;`.
2700 TraitAlias(Generics, GenericBounds),
2701 /// An implementation.
2703 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2704 Impl(Box<ImplKind>),
2705 /// A macro invocation.
2707 /// E.g., `foo!(..)`.
2710 /// A macro definition.
2714 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2715 rustc_data_structures::static_assert_size!(ItemKind, 112);
2718 pub fn article(&self) -> &str {
2721 Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
2722 | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
2723 ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
2727 pub fn descr(&self) -> &str {
2729 ItemKind::ExternCrate(..) => "extern crate",
2730 ItemKind::Use(..) => "`use` import",
2731 ItemKind::Static(..) => "static item",
2732 ItemKind::Const(..) => "constant item",
2733 ItemKind::Fn(..) => "function",
2734 ItemKind::Mod(..) => "module",
2735 ItemKind::ForeignMod(..) => "extern block",
2736 ItemKind::GlobalAsm(..) => "global asm item",
2737 ItemKind::TyAlias(..) => "type alias",
2738 ItemKind::Enum(..) => "enum",
2739 ItemKind::Struct(..) => "struct",
2740 ItemKind::Union(..) => "union",
2741 ItemKind::Trait(..) => "trait",
2742 ItemKind::TraitAlias(..) => "trait alias",
2743 ItemKind::MacCall(..) => "item macro invocation",
2744 ItemKind::MacroDef(..) => "macro definition",
2745 ItemKind::Impl { .. } => "implementation",
2749 pub fn generics(&self) -> Option<&Generics> {
2751 Self::Fn(box FnKind(_, _, generics, _))
2752 | Self::TyAlias(box TyAliasKind(_, generics, ..))
2753 | Self::Enum(_, generics)
2754 | Self::Struct(_, generics)
2755 | Self::Union(_, generics)
2756 | Self::Trait(box TraitKind(_, _, generics, ..))
2757 | Self::TraitAlias(generics, _)
2758 | Self::Impl(box ImplKind { generics, .. }) => Some(generics),
2764 /// Represents associated items.
2765 /// These include items in `impl` and `trait` definitions.
2766 pub type AssocItem = Item<AssocItemKind>;
2768 /// Represents associated item kinds.
2770 /// The term "provided" in the variants below refers to the item having a default
2771 /// definition / body. Meanwhile, a "required" item lacks a definition / body.
2772 /// In an implementation, all items must be provided.
2773 /// The `Option`s below denote the bodies, where `Some(_)`
2774 /// means "provided" and conversely `None` means "required".
2775 #[derive(Clone, Encodable, Decodable, Debug)]
2776 pub enum AssocItemKind {
2777 /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
2778 /// If `def` is parsed, then the constant is provided, and otherwise required.
2779 Const(Defaultness, P<Ty>, Option<P<Expr>>),
2780 /// An associated function.
2782 /// An associated type.
2783 TyAlias(Box<TyAliasKind>),
2784 /// A macro expanding to associated items.
2788 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2789 rustc_data_structures::static_assert_size!(AssocItemKind, 72);
2791 impl AssocItemKind {
2792 pub fn defaultness(&self) -> Defaultness {
2794 Self::Const(def, ..)
2795 | Self::Fn(box FnKind(def, ..))
2796 | Self::TyAlias(box TyAliasKind(def, ..)) => def,
2797 Self::MacCall(..) => Defaultness::Final,
2802 impl From<AssocItemKind> for ItemKind {
2803 fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
2804 match assoc_item_kind {
2805 AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
2806 AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
2807 AssocItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
2808 AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
2813 impl TryFrom<ItemKind> for AssocItemKind {
2814 type Error = ItemKind;
2816 fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
2817 Ok(match item_kind {
2818 ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
2819 ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
2820 ItemKind::TyAlias(ty_alias_kind) => AssocItemKind::TyAlias(ty_alias_kind),
2821 ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
2822 _ => return Err(item_kind),
2827 /// An item in `extern` block.
2828 #[derive(Clone, Encodable, Decodable, Debug)]
2829 pub enum ForeignItemKind {
2830 /// A foreign static item (`static FOO: u8`).
2831 Static(P<Ty>, Mutability, Option<P<Expr>>),
2832 /// An foreign function.
2834 /// An foreign type.
2835 TyAlias(Box<TyAliasKind>),
2836 /// A macro expanding to foreign items.
2840 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
2841 rustc_data_structures::static_assert_size!(ForeignItemKind, 72);
2843 impl From<ForeignItemKind> for ItemKind {
2844 fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
2845 match foreign_item_kind {
2846 ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
2847 ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
2848 ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
2849 ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
2854 impl TryFrom<ItemKind> for ForeignItemKind {
2855 type Error = ItemKind;
2857 fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
2858 Ok(match item_kind {
2859 ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
2860 ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
2861 ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
2862 ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
2863 _ => return Err(item_kind),
2868 pub type ForeignItem = Item<ForeignItemKind>;