1 // The Rust abstract syntax tree.
3 pub use GenericArgs::*;
4 pub use UnsafeSource::*;
5 pub use crate::symbol::{Ident, Symbol as Name};
6 pub use crate::util::parser::ExprPrecedence;
8 use crate::ext::hygiene::{ExpnId, SyntaxContext};
9 use crate::parse::token::{self, DelimToken};
10 use crate::print::pprust;
12 use crate::source_map::{dummy_spanned, respan, Spanned};
13 use crate::symbol::{kw, sym, Symbol};
14 use crate::tokenstream::TokenStream;
17 use rustc_data_structures::indexed_vec::Idx;
18 #[cfg(target_arch = "x86_64")]
19 use rustc_data_structures::static_assert_size;
20 use rustc_target::spec::abi::Abi;
21 use syntax_pos::{Span, DUMMY_SP};
23 use rustc_data_structures::fx::FxHashSet;
24 use rustc_data_structures::sync::Lrc;
25 use rustc_serialize::{self, Decoder, Encoder};
28 pub use rustc_target::abi::FloatTy;
33 #[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
38 impl fmt::Debug for Label {
39 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
40 write!(f, "label({:?})", self.ident)
44 #[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
50 impl fmt::Debug for Lifetime {
51 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
61 impl fmt::Display for Lifetime {
62 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
63 write!(f, "{}", self.ident.name.as_str())
67 /// A "Path" is essentially Rust's notion of a name.
69 /// It's represented as a sequence of identifiers,
70 /// along with a bunch of supporting information.
72 /// E.g., `std::cmp::PartialEq`.
73 #[derive(Clone, RustcEncodable, RustcDecodable)]
76 /// The segments in the path: the things separated by `::`.
77 /// Global paths begin with `kw::PathRoot`.
78 pub segments: Vec<PathSegment>,
81 impl PartialEq<Symbol> for Path {
82 fn eq(&self, symbol: &Symbol) -> bool {
83 self.segments.len() == 1 && {
84 self.segments[0].ident.name == *symbol
89 impl fmt::Debug for Path {
90 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
91 write!(f, "path({})", pprust::path_to_string(self))
95 impl fmt::Display for Path {
96 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
97 write!(f, "{}", pprust::path_to_string(self))
102 // Convert a span and an identifier to the corresponding
104 pub fn from_ident(ident: Ident) -> Path {
106 segments: vec![PathSegment::from_ident(ident)],
111 pub fn is_global(&self) -> bool {
112 !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
116 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
118 /// E.g., `std`, `String` or `Box<T>`.
119 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
120 pub struct PathSegment {
121 /// The identifier portion of this path segment.
126 /// Type/lifetime parameters attached to this path. They come in
127 /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
128 /// `None` means that no parameter list is supplied (`Path`),
129 /// `Some` means that parameter list is supplied (`Path<X, Y>`)
130 /// but it can be empty (`Path<>`).
131 /// `P` is used as a size optimization for the common case with no parameters.
132 pub args: Option<P<GenericArgs>>,
136 pub fn from_ident(ident: Ident) -> Self {
137 PathSegment { ident, id: DUMMY_NODE_ID, args: None }
139 pub fn path_root(span: Span) -> Self {
140 PathSegment::from_ident(Ident::new(kw::PathRoot, span))
144 /// The arguments of a path segment.
146 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
147 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
148 pub enum GenericArgs {
149 /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
150 AngleBracketed(AngleBracketedArgs),
151 /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
152 Parenthesized(ParenthesizedArgs),
156 pub fn is_parenthesized(&self) -> bool {
158 Parenthesized(..) => true,
163 pub fn is_angle_bracketed(&self) -> bool {
165 AngleBracketed(..) => true,
170 pub fn span(&self) -> Span {
172 AngleBracketed(ref data) => data.span,
173 Parenthesized(ref data) => data.span,
178 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
179 pub enum GenericArg {
186 pub fn span(&self) -> Span {
188 GenericArg::Lifetime(lt) => lt.ident.span,
189 GenericArg::Type(ty) => ty.span,
190 GenericArg::Const(ct) => ct.value.span,
195 /// A path like `Foo<'a, T>`.
196 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Default)]
197 pub struct AngleBracketedArgs {
198 /// The overall span.
200 /// The arguments for this path segment.
201 pub args: Vec<GenericArg>,
202 /// Constraints on associated types, if any.
203 /// E.g., `Foo<A = Bar, B: Baz>`.
204 pub constraints: Vec<AssocTyConstraint>,
207 impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
208 fn into(self) -> Option<P<GenericArgs>> {
209 Some(P(GenericArgs::AngleBracketed(self)))
213 impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
214 fn into(self) -> Option<P<GenericArgs>> {
215 Some(P(GenericArgs::Parenthesized(self)))
219 /// A path like `Foo(A, B) -> C`.
220 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
221 pub struct ParenthesizedArgs {
226 pub inputs: Vec<P<Ty>>,
229 pub output: Option<P<Ty>>,
232 impl ParenthesizedArgs {
233 pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
236 args: self.inputs.iter().cloned().map(|input| GenericArg::Type(input)).collect(),
242 // hack to ensure that we don't try to access the private parts of `NodeId` in this module
244 use rustc_data_structures::indexed_vec::Idx;
245 use rustc_data_structures::newtype_index;
249 DEBUG_FORMAT = "NodeId({})"
254 pub use node_id_inner::NodeId;
257 pub fn placeholder_from_expn_id(expn_id: ExpnId) -> Self {
258 NodeId::from_u32(expn_id.as_u32())
261 pub fn placeholder_to_expn_id(self) -> ExpnId {
262 ExpnId::from_u32(self.as_u32())
266 impl fmt::Display for NodeId {
267 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
268 fmt::Display::fmt(&self.as_u32(), f)
272 impl rustc_serialize::UseSpecializedEncodable for NodeId {
273 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
274 s.emit_u32(self.as_u32())
278 impl rustc_serialize::UseSpecializedDecodable for NodeId {
279 fn default_decode<D: Decoder>(d: &mut D) -> Result<NodeId, D::Error> {
280 d.read_u32().map(NodeId::from_u32)
284 /// `NodeId` used to represent the root of the crate.
285 pub const CRATE_NODE_ID: NodeId = NodeId::from_u32_const(0);
287 /// When parsing and doing expansions, we initially give all AST nodes this AST
288 /// node value. Then later, in the renumber pass, we renumber them to have
289 /// small, positive ids.
290 pub const DUMMY_NODE_ID: NodeId = NodeId::MAX;
292 /// A modifier on a bound, currently this is only used for `?Sized`, where the
293 /// modifier is `Maybe`. Negative bounds should also be handled here.
294 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
295 pub enum TraitBoundModifier {
300 /// The AST represents all type param bounds as types.
301 /// `typeck::collect::compute_bounds` matches these against
302 /// the "special" built-in traits (see `middle::lang_items`) and
303 /// detects `Copy`, `Send` and `Sync`.
304 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
305 pub enum GenericBound {
306 Trait(PolyTraitRef, TraitBoundModifier),
311 pub fn span(&self) -> Span {
313 &GenericBound::Trait(ref t, ..) => t.span,
314 &GenericBound::Outlives(ref l) => l.ident.span,
319 pub type GenericBounds = Vec<GenericBound>;
321 /// Specifies the enforced ordering for generic parameters. In the future,
322 /// if we wanted to relax this order, we could override `PartialEq` and
323 /// `PartialOrd`, to allow the kinds to be unordered.
324 #[derive(PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
325 pub enum ParamKindOrd {
331 impl fmt::Display for ParamKindOrd {
332 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
334 ParamKindOrd::Lifetime => "lifetime".fmt(f),
335 ParamKindOrd::Type => "type".fmt(f),
336 ParamKindOrd::Const => "const".fmt(f),
341 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
342 pub enum GenericParamKind {
343 /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
345 Type { default: Option<P<Ty>> },
349 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
350 pub struct GenericParam {
353 pub attrs: ThinVec<Attribute>,
354 pub bounds: GenericBounds,
356 pub kind: GenericParamKind,
359 /// Represents lifetime, type and const parameters attached to a declaration of
360 /// a function, enum, trait, etc.
361 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
362 pub struct Generics {
363 pub params: Vec<GenericParam>,
364 pub where_clause: WhereClause,
368 impl Default for Generics {
369 /// Creates an instance of `Generics`.
370 fn default() -> Generics {
373 where_clause: WhereClause {
374 predicates: Vec::new(),
382 /// A where-clause in a definition.
383 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
384 pub struct WhereClause {
385 pub predicates: Vec<WherePredicate>,
389 /// A single predicate in a where-clause.
390 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
391 pub enum WherePredicate {
392 /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
393 BoundPredicate(WhereBoundPredicate),
394 /// A lifetime predicate (e.g., `'a: 'b + 'c`).
395 RegionPredicate(WhereRegionPredicate),
396 /// An equality predicate (unsupported).
397 EqPredicate(WhereEqPredicate),
400 impl WherePredicate {
401 pub fn span(&self) -> Span {
403 &WherePredicate::BoundPredicate(ref p) => p.span,
404 &WherePredicate::RegionPredicate(ref p) => p.span,
405 &WherePredicate::EqPredicate(ref p) => p.span,
412 /// E.g., `for<'c> Foo: Send + Clone + 'c`.
413 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
414 pub struct WhereBoundPredicate {
416 /// Any generics from a `for` binding
417 pub bound_generic_params: Vec<GenericParam>,
418 /// The type being bounded
419 pub bounded_ty: P<Ty>,
420 /// Trait and lifetime bounds (`Clone+Send+'static`)
421 pub bounds: GenericBounds,
424 /// A lifetime predicate.
426 /// E.g., `'a: 'b + 'c`.
427 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
428 pub struct WhereRegionPredicate {
430 pub lifetime: Lifetime,
431 pub bounds: GenericBounds,
434 /// An equality predicate (unsupported).
437 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
438 pub struct WhereEqPredicate {
445 /// The set of `MetaItem`s that define the compilation environment of the crate,
446 /// used to drive conditional compilation.
447 pub type CrateConfig = FxHashSet<(Name, Option<Symbol>)>;
449 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
452 pub attrs: Vec<Attribute>,
456 /// Possible values inside of compile-time attribute lists.
458 /// E.g., the '..' in `#[name(..)]`.
459 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
460 pub enum NestedMetaItem {
461 /// A full MetaItem, for recursive meta items.
465 /// E.g., `"foo"`, `64`, `true`.
469 /// A spanned compile-time attribute item.
471 /// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
472 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
473 pub struct MetaItem {
475 pub node: MetaItemKind,
479 /// A compile-time attribute item.
481 /// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
482 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
483 pub enum MetaItemKind {
486 /// E.g., `test` as in `#[test]`.
490 /// E.g., `derive(..)` as in `#[derive(..)]`.
491 List(Vec<NestedMetaItem>),
492 /// Name value meta item.
494 /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
498 /// A Block (`{ .. }`).
500 /// E.g., `{ .. }` as in `fn foo() { .. }`.
501 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
503 /// Statements in a block
504 pub stmts: Vec<Stmt>,
506 /// Distinguishes between `unsafe { ... }` and `{ ... }`
507 pub rules: BlockCheckMode,
511 #[derive(Clone, RustcEncodable, RustcDecodable)]
518 impl fmt::Debug for Pat {
519 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
520 write!(f, "pat({}: {})", self.id, pprust::pat_to_string(self))
525 /// Attempt reparsing the pattern as a type.
526 /// This is intended for use by diagnostics.
527 pub(super) fn to_ty(&self) -> Option<P<Ty>> {
528 let node = match &self.node {
529 // In a type expression `_` is an inference variable.
530 PatKind::Wild => TyKind::Infer,
531 // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
532 PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), ident, None) => {
533 TyKind::Path(None, Path::from_ident(*ident))
535 PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
536 PatKind::Mac(mac) => TyKind::Mac(mac.clone()),
537 // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
538 PatKind::Ref(pat, mutbl) => pat
540 .map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?,
541 // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
542 // when `P` can be reparsed as a type `T`.
543 PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
544 // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
545 // assuming `T0` to `Tn` are all syntactically valid as types.
546 PatKind::Tuple(pats) => {
547 let mut tys = Vec::with_capacity(pats.len());
548 // FIXME(#48994) - could just be collected into an Option<Vec>
550 tys.push(pat.to_ty()?);
564 pub fn walk<F>(&self, it: &mut F) -> bool
566 F: FnMut(&Pat) -> bool,
573 PatKind::Ident(_, _, Some(p)) => p.walk(it),
574 PatKind::Struct(_, fields, _) => fields.iter().all(|field| field.pat.walk(it)),
575 PatKind::TupleStruct(_, s) | PatKind::Tuple(s) | PatKind::Slice(s) => {
576 s.iter().all(|p| p.walk(it))
578 PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
585 | PatKind::Mac(_) => true,
589 /// Is this a `..` pattern?
590 pub fn is_rest(&self) -> bool {
592 PatKind::Rest => true,
598 /// A single field in a struct pattern
600 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
601 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
602 /// except is_shorthand is true
603 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
604 pub struct FieldPat {
605 /// The identifier for the field
607 /// The pattern the field is destructured to
609 pub is_shorthand: bool,
610 pub attrs: ThinVec<Attribute>,
615 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
616 pub enum BindingMode {
621 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
623 Included(RangeSyntax),
627 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
628 pub enum RangeSyntax {
633 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
635 /// Represents a wildcard pattern (`_`).
638 /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
639 /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
640 /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
641 /// during name resolution.
642 Ident(BindingMode, Ident, Option<P<Pat>>),
644 /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
645 /// The `bool` is `true` in the presence of a `..`.
646 Struct(Path, Vec<FieldPat>, /* recovered */ bool),
648 /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
649 TupleStruct(Path, Vec<P<Pat>>),
651 /// A possibly qualified path pattern.
652 /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
653 /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
654 /// only legally refer to associated constants.
655 Path(Option<QSelf>, Path),
657 /// A tuple pattern (`(a, b)`).
663 /// A reference pattern (e.g., `&mut (a, b)`).
664 Ref(P<Pat>, Mutability),
669 /// A range pattern (e.g., `1...2`, `1..=2` or `1..2`).
670 Range(P<Expr>, P<Expr>, Spanned<RangeEnd>),
672 /// A slice pattern `[a, b, c]`.
675 /// A rest pattern `..`.
677 /// Syntactically it is valid anywhere.
679 /// Semantically however, it only has meaning immediately inside:
680 /// - a slice pattern: `[a, .., b]`,
681 /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
682 /// - a tuple pattern: `(a, .., b)`,
683 /// - a tuple struct/variant pattern: `$path(a, .., b)`.
685 /// In all of these cases, an additional restriction applies,
686 /// only one rest pattern may occur in the pattern sequences.
689 /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
692 /// A macro pattern; pre-expansion.
697 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug, Copy,
699 pub enum Mutability {
704 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
706 /// The `+` operator (addition)
708 /// The `-` operator (subtraction)
710 /// The `*` operator (multiplication)
712 /// The `/` operator (division)
714 /// The `%` operator (modulus)
716 /// The `&&` operator (logical and)
718 /// The `||` operator (logical or)
720 /// The `^` operator (bitwise xor)
722 /// The `&` operator (bitwise and)
724 /// The `|` operator (bitwise or)
726 /// The `<<` operator (shift left)
728 /// The `>>` operator (shift right)
730 /// The `==` operator (equality)
732 /// The `<` operator (less than)
734 /// The `<=` operator (less than or equal to)
736 /// The `!=` operator (not equal to)
738 /// The `>=` operator (greater than or equal to)
740 /// The `>` operator (greater than)
745 pub fn to_string(&self) -> &'static str {
768 pub fn lazy(&self) -> bool {
770 BinOpKind::And | BinOpKind::Or => true,
775 pub fn is_shift(&self) -> bool {
777 BinOpKind::Shl | BinOpKind::Shr => true,
782 pub fn is_comparison(&self) -> bool {
785 Eq | Lt | Le | Ne | Gt | Ge => true,
786 And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
790 /// Returns `true` if the binary operator takes its arguments by value
791 pub fn is_by_value(&self) -> bool {
792 !self.is_comparison()
796 pub type BinOp = Spanned<BinOpKind>;
798 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
800 /// The `*` operator for dereferencing
802 /// The `!` operator for logical inversion
804 /// The `-` operator for negation
809 /// Returns `true` if the unary operator takes its argument by value
810 pub fn is_by_value(u: UnOp) -> bool {
812 UnOp::Neg | UnOp::Not => true,
817 pub fn to_string(op: UnOp) -> &'static str {
827 #[derive(Clone, RustcEncodable, RustcDecodable)]
835 pub fn add_trailing_semicolon(mut self) -> Self {
836 self.node = match self.node {
837 StmtKind::Expr(expr) => StmtKind::Semi(expr),
838 StmtKind::Mac(mac) => {
839 StmtKind::Mac(mac.map(|(mac, _style, attrs)| (mac, MacStmtStyle::Semicolon, attrs)))
846 pub fn is_item(&self) -> bool {
848 StmtKind::Item(_) => true,
853 pub fn is_expr(&self) -> bool {
855 StmtKind::Expr(_) => true,
861 impl fmt::Debug for Stmt {
862 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
867 pprust::stmt_to_string(self)
872 #[derive(Clone, RustcEncodable, RustcDecodable)]
874 /// A local (let) binding.
877 /// An item definition.
880 /// Expr without trailing semi-colon.
882 /// Expr with a trailing semi-colon.
885 Mac(P<(Mac, MacStmtStyle, ThinVec<Attribute>)>),
888 #[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
889 pub enum MacStmtStyle {
890 /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
891 /// `foo!(...);`, `foo![...];`).
893 /// The macro statement had braces (e.g., `foo! { ... }`).
895 /// The macro statement had parentheses or brackets and no semicolon (e.g.,
896 /// `foo!(...)`). All of these will end up being converted into macro
901 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
902 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
905 pub ty: Option<P<Ty>>,
906 /// Initializer expression to set the value, if any.
907 pub init: Option<P<Expr>>,
910 pub attrs: ThinVec<Attribute>,
913 /// An arm of a 'match'.
915 /// E.g., `0..=10 => { println!("match!") }` as in
919 /// 0..=10 => { println!("match!") },
920 /// _ => { println!("no match!") },
923 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
925 pub attrs: Vec<Attribute>,
926 pub pats: Vec<P<Pat>>,
927 pub guard: Option<P<Expr>>,
933 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
938 pub is_shorthand: bool,
939 pub attrs: ThinVec<Attribute>,
943 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
944 pub enum BlockCheckMode {
946 Unsafe(UnsafeSource),
949 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
950 pub enum UnsafeSource {
955 /// A constant (expression) that's not an item or associated item,
956 /// but needs its own `DefId` for type-checking, const-eval, etc.
957 /// These are usually found nested inside types (e.g., array lengths)
958 /// or expressions (e.g., repeat counts), and also used to define
959 /// explicit discriminant values for enum variants.
960 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
961 pub struct AnonConst {
967 #[derive(Clone, RustcEncodable, RustcDecodable)]
972 pub attrs: ThinVec<Attribute>,
975 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
976 #[cfg(target_arch = "x86_64")]
977 static_assert_size!(Expr, 96);
980 /// Whether this expression would be valid somewhere that expects a value; for example, an `if`
982 pub fn returns(&self) -> bool {
983 if let ExprKind::Block(ref block, _) = self.node {
984 match block.stmts.last().map(|last_stmt| &last_stmt.node) {
986 Some(&StmtKind::Expr(_)) => true,
987 Some(&StmtKind::Semi(ref expr)) => {
988 if let ExprKind::Ret(_) = expr.node {
989 // last statement is explicit return
995 // This is a block that doesn't end in either an implicit or explicit return
999 // This is not a block, it is a value
1004 fn to_bound(&self) -> Option<GenericBound> {
1006 ExprKind::Path(None, path) => Some(GenericBound::Trait(
1007 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
1008 TraitBoundModifier::None,
1014 pub(super) fn to_ty(&self) -> Option<P<Ty>> {
1015 let node = match &self.node {
1016 ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
1017 ExprKind::Mac(mac) => TyKind::Mac(mac.clone()),
1018 ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
1019 ExprKind::AddrOf(mutbl, expr) => expr
1021 .map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?,
1022 ExprKind::Repeat(expr, expr_len) => {
1023 expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
1025 ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
1026 ExprKind::Tup(exprs) => {
1029 .map(|expr| expr.to_ty())
1030 .collect::<Option<Vec<_>>>()?;
1033 ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
1034 if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
1035 TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
1050 pub fn precedence(&self) -> ExprPrecedence {
1052 ExprKind::Box(_) => ExprPrecedence::Box,
1053 ExprKind::Array(_) => ExprPrecedence::Array,
1054 ExprKind::Call(..) => ExprPrecedence::Call,
1055 ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
1056 ExprKind::Tup(_) => ExprPrecedence::Tup,
1057 ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
1058 ExprKind::Unary(..) => ExprPrecedence::Unary,
1059 ExprKind::Lit(_) => ExprPrecedence::Lit,
1060 ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
1061 ExprKind::Let(..) => ExprPrecedence::Let,
1062 ExprKind::If(..) => ExprPrecedence::If,
1063 ExprKind::While(..) => ExprPrecedence::While,
1064 ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
1065 ExprKind::Loop(..) => ExprPrecedence::Loop,
1066 ExprKind::Match(..) => ExprPrecedence::Match,
1067 ExprKind::Closure(..) => ExprPrecedence::Closure,
1068 ExprKind::Block(..) => ExprPrecedence::Block,
1069 ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
1070 ExprKind::Async(..) => ExprPrecedence::Async,
1071 ExprKind::Await(..) => ExprPrecedence::Await,
1072 ExprKind::Assign(..) => ExprPrecedence::Assign,
1073 ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
1074 ExprKind::Field(..) => ExprPrecedence::Field,
1075 ExprKind::Index(..) => ExprPrecedence::Index,
1076 ExprKind::Range(..) => ExprPrecedence::Range,
1077 ExprKind::Path(..) => ExprPrecedence::Path,
1078 ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
1079 ExprKind::Break(..) => ExprPrecedence::Break,
1080 ExprKind::Continue(..) => ExprPrecedence::Continue,
1081 ExprKind::Ret(..) => ExprPrecedence::Ret,
1082 ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
1083 ExprKind::Mac(..) => ExprPrecedence::Mac,
1084 ExprKind::Struct(..) => ExprPrecedence::Struct,
1085 ExprKind::Repeat(..) => ExprPrecedence::Repeat,
1086 ExprKind::Paren(..) => ExprPrecedence::Paren,
1087 ExprKind::Try(..) => ExprPrecedence::Try,
1088 ExprKind::Yield(..) => ExprPrecedence::Yield,
1089 ExprKind::Err => ExprPrecedence::Err,
1094 impl fmt::Debug for Expr {
1095 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1096 write!(f, "expr({}: {})", self.id, pprust::expr_to_string(self))
1100 /// Limit types of a range (inclusive or exclusive)
1101 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1102 pub enum RangeLimits {
1103 /// Inclusive at the beginning, exclusive at the end
1105 /// Inclusive at the beginning and end
1109 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1111 /// A `box x` expression.
1113 /// An array (`[a, b, c, d]`)
1114 Array(Vec<P<Expr>>),
1117 /// The first field resolves to the function itself,
1118 /// and the second field is the list of arguments.
1119 /// This also represents calling the constructor of
1120 /// tuple-like ADTs such as tuple structs and enum variants.
1121 Call(P<Expr>, Vec<P<Expr>>),
1122 /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
1124 /// The `PathSegment` represents the method name and its generic arguments
1125 /// (within the angle brackets).
1126 /// The first element of the vector of an `Expr` is the expression that evaluates
1127 /// to the object on which the method is being called on (the receiver),
1128 /// and the remaining elements are the rest of the arguments.
1129 /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
1130 /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
1131 MethodCall(PathSegment, Vec<P<Expr>>),
1132 /// A tuple (e.g., `(a, b, c, d)`).
1134 /// A binary operation (e.g., `a + b`, `a * b`).
1135 Binary(BinOp, P<Expr>, P<Expr>),
1136 /// A unary operation (e.g., `!x`, `*x`).
1137 Unary(UnOp, P<Expr>),
1138 /// A literal (e.g., `1`, `"foo"`).
1140 /// A cast (e.g., `foo as f64`).
1141 Cast(P<Expr>, P<Ty>),
1142 /// A type ascription (e.g., `42: usize`).
1143 Type(P<Expr>, P<Ty>),
1144 /// A `let pats = expr` expression that is only semantically allowed in the condition
1145 /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
1147 /// The `Vec<P<Pat>>` is for or-patterns at the top level.
1148 /// FIXME(54883): Change this to just `P<Pat>`.
1149 Let(Vec<P<Pat>>, P<Expr>),
1150 /// An `if` block, with an optional `else` block.
1152 /// `if expr { block } else { expr }`
1153 If(P<Expr>, P<Block>, Option<P<Expr>>),
1154 /// A while loop, with an optional label.
1156 /// `'label: while expr { block }`
1157 While(P<Expr>, P<Block>, Option<Label>),
1158 /// A `for` loop, with an optional label.
1160 /// `'label: for pat in expr { block }`
1162 /// This is desugared to a combination of `loop` and `match` expressions.
1163 ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
1164 /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
1166 /// `'label: loop { block }`
1167 Loop(P<Block>, Option<Label>),
1168 /// A `match` block.
1169 Match(P<Expr>, Vec<Arm>),
1170 /// A closure (e.g., `move |a, b, c| a + b + c`).
1172 /// The final span is the span of the argument block `|...|`.
1173 Closure(CaptureBy, IsAsync, Movability, P<FnDecl>, P<Expr>, Span),
1174 /// A block (`'label: { ... }`).
1175 Block(P<Block>, Option<Label>),
1176 /// An async block (`async move { ... }`).
1178 /// The `NodeId` is the `NodeId` for the closure that results from
1179 /// desugaring an async block, just like the NodeId field in the
1180 /// `IsAsync` enum. This is necessary in order to create a def for the
1181 /// closure which can be used as a parent of any child defs. Defs
1182 /// created during lowering cannot be made the parent of any other
1183 /// preexisting defs.
1184 Async(CaptureBy, NodeId, P<Block>),
1185 /// An await expression (`my_future.await`).
1188 /// A try block (`try { ... }`).
1191 /// An assignment (`a = foo()`).
1192 Assign(P<Expr>, P<Expr>),
1193 /// An assignment with an operator.
1196 AssignOp(BinOp, P<Expr>, P<Expr>),
1197 /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
1198 Field(P<Expr>, Ident),
1199 /// An indexing operation (e.g., `foo[2]`).
1200 Index(P<Expr>, P<Expr>),
1201 /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
1202 Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
1204 /// Variable reference, possibly containing `::` and/or type
1205 /// parameters (e.g., `foo::bar::<baz>`).
1207 /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
1208 Path(Option<QSelf>, Path),
1210 /// A referencing operation (`&a` or `&mut a`).
1211 AddrOf(Mutability, P<Expr>),
1212 /// A `break`, with an optional label to break, and an optional expression.
1213 Break(Option<Label>, Option<P<Expr>>),
1214 /// A `continue`, with an optional label.
1215 Continue(Option<Label>),
1216 /// A `return`, with an optional value to be returned.
1217 Ret(Option<P<Expr>>),
1219 /// Output of the `asm!()` macro.
1220 InlineAsm(P<InlineAsm>),
1222 /// A macro invocation; pre-expansion.
1225 /// A struct literal expression.
1227 /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. base}`,
1228 /// where `base` is the `Option<Expr>`.
1229 Struct(Path, Vec<Field>, Option<P<Expr>>),
1231 /// An array literal constructed from one repeated element.
1233 /// E.g., `[1; 5]`. The expression is the element to be
1234 /// repeated; the constant is the number of times to repeat it.
1235 Repeat(P<Expr>, AnonConst),
1237 /// No-op: used solely so we can pretty-print faithfully.
1240 /// A try expression (`expr?`).
1243 /// A `yield`, with an optional value to be yielded.
1244 Yield(Option<P<Expr>>),
1246 /// Placeholder for an expression that wasn't syntactically well formed in some way.
1250 /// The explicit `Self` type in a "qualified path". The actual
1251 /// path, including the trait and the associated item, is stored
1252 /// separately. `position` represents the index of the associated
1253 /// item qualified with this `Self` type.
1255 /// ```ignore (only-for-syntax-highlight)
1256 /// <Vec<T> as a::b::Trait>::AssociatedItem
1257 /// ^~~~~ ~~~~~~~~~~~~~~^
1260 /// <Vec<T>>::AssociatedItem
1264 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1268 /// The span of `a::b::Trait` in a path like `<Vec<T> as
1269 /// a::b::Trait>::AssociatedItem`; in the case where `position ==
1270 /// 0`, this is an empty span.
1271 pub path_span: Span,
1272 pub position: usize,
1275 /// A capture clause.
1276 #[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1277 pub enum CaptureBy {
1282 /// The movability of a generator / closure literal.
1283 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
1284 pub enum Movability {
1289 /// Represents a macro invocation. The `Path` indicates which macro
1290 /// is being invoked, and the vector of token-trees contains the source
1291 /// of the macro invocation.
1293 /// N.B., the additional ident for a `macro_rules`-style macro is actually
1294 /// stored in the enclosing item.
1295 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1298 pub delim: MacDelimiter,
1299 pub tts: TokenStream,
1301 pub prior_type_ascription: Option<(Span, bool)>,
1304 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
1305 pub enum MacDelimiter {
1312 pub fn stream(&self) -> TokenStream {
1318 crate fn to_token(self) -> DelimToken {
1320 MacDelimiter::Parenthesis => DelimToken::Paren,
1321 MacDelimiter::Bracket => DelimToken::Bracket,
1322 MacDelimiter::Brace => DelimToken::Brace,
1327 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1328 pub struct MacroDef {
1329 pub tokens: TokenStream,
1334 pub fn stream(&self) -> TokenStream {
1335 self.tokens.clone().into()
1339 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy, Hash, PartialEq)]
1341 /// A regular string, like `"foo"`.
1343 /// A raw string, like `r##"foo"##`.
1345 /// The value is the number of `#` symbols used.
1350 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1352 /// The original literal token as written in source code.
1353 pub token: token::Lit,
1354 /// The "semantic" representation of the literal lowered from the original tokens.
1355 /// Strings are unescaped, hexadecimal forms are eliminated, etc.
1356 /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
1361 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy, Hash, PartialEq)]
1362 pub enum LitIntType {
1370 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
1371 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq)]
1373 /// A string literal (`"foo"`).
1374 Str(Symbol, StrStyle),
1375 /// A byte string (`b"foo"`).
1376 ByteStr(Lrc<Vec<u8>>),
1377 /// A byte char (`b'f'`).
1379 /// A character literal (`'a'`).
1381 /// An integer literal (`1`).
1382 Int(u128, LitIntType),
1383 /// A float literal (`1f64` or `1E10f64`).
1384 Float(Symbol, FloatTy),
1385 /// A float literal without a suffix (`1.0 or 1.0E10`).
1386 FloatUnsuffixed(Symbol),
1387 /// A boolean literal.
1389 /// Placeholder for a literal that wasn't well-formed in some way.
1394 /// Returns `true` if this literal is a string.
1395 pub fn is_str(&self) -> bool {
1397 LitKind::Str(..) => true,
1402 /// Returns `true` if this literal is byte literal string.
1403 pub fn is_bytestr(&self) -> bool {
1405 LitKind::ByteStr(_) => true,
1410 /// Returns `true` if this is a numeric literal.
1411 pub fn is_numeric(&self) -> bool {
1413 LitKind::Int(..) | LitKind::Float(..) | LitKind::FloatUnsuffixed(..) => true,
1418 /// Returns `true` if this literal has no suffix.
1419 /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
1420 pub fn is_unsuffixed(&self) -> bool {
1422 // unsuffixed variants
1424 | LitKind::ByteStr(..)
1427 | LitKind::Int(_, LitIntType::Unsuffixed)
1428 | LitKind::FloatUnsuffixed(..)
1430 | LitKind::Err(..) => true,
1431 // suffixed variants
1432 LitKind::Int(_, LitIntType::Signed(..))
1433 | LitKind::Int(_, LitIntType::Unsigned(..))
1434 | LitKind::Float(..) => false,
1438 /// Returns `true` if this literal has a suffix.
1439 pub fn is_suffixed(&self) -> bool {
1440 !self.is_unsuffixed()
1444 // N.B., If you change this, you'll probably want to change the corresponding
1445 // type structure in `middle/ty.rs` as well.
1446 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1449 pub mutbl: Mutability,
1452 /// Represents a method's signature in a trait declaration,
1453 /// or in an implementation.
1454 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1455 pub struct MethodSig {
1456 pub header: FnHeader,
1457 pub decl: P<FnDecl>,
1460 /// Represents an item declaration within a trait declaration,
1461 /// possibly including a default implementation. A trait item is
1462 /// either required (meaning it doesn't have an implementation, just a
1463 /// signature) or provided (meaning it has a default implementation).
1464 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1465 pub struct TraitItem {
1468 pub attrs: Vec<Attribute>,
1469 pub generics: Generics,
1470 pub node: TraitItemKind,
1472 /// See `Item::tokens` for what this is.
1473 pub tokens: Option<TokenStream>,
1476 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1477 pub enum TraitItemKind {
1478 Const(P<Ty>, Option<P<Expr>>),
1479 Method(MethodSig, Option<P<Block>>),
1480 Type(GenericBounds, Option<P<Ty>>),
1484 /// Represents anything within an `impl` block.
1485 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1486 pub struct ImplItem {
1489 pub vis: Visibility,
1490 pub defaultness: Defaultness,
1491 pub attrs: Vec<Attribute>,
1492 pub generics: Generics,
1493 pub node: ImplItemKind,
1495 /// See `Item::tokens` for what this is.
1496 pub tokens: Option<TokenStream>,
1499 /// Represents various kinds of content within an `impl`.
1500 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1501 pub enum ImplItemKind {
1502 Const(P<Ty>, P<Expr>),
1503 Method(MethodSig, P<Block>),
1505 OpaqueTy(GenericBounds),
1509 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy)]
1519 impl fmt::Debug for IntTy {
1520 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1521 fmt::Display::fmt(self, f)
1525 impl fmt::Display for IntTy {
1526 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1527 write!(f, "{}", self.ty_to_string())
1532 pub fn ty_to_string(&self) -> &'static str {
1534 IntTy::Isize => "isize",
1536 IntTy::I16 => "i16",
1537 IntTy::I32 => "i32",
1538 IntTy::I64 => "i64",
1539 IntTy::I128 => "i128",
1543 pub fn to_symbol(&self) -> Symbol {
1545 IntTy::Isize => sym::isize,
1546 IntTy::I8 => sym::i8,
1547 IntTy::I16 => sym::i16,
1548 IntTy::I32 => sym::i32,
1549 IntTy::I64 => sym::i64,
1550 IntTy::I128 => sym::i128,
1554 pub fn val_to_string(&self, val: i128) -> String {
1555 // Cast to a `u128` so we can correctly print `INT128_MIN`. All integral types
1556 // are parsed as `u128`, so we wouldn't want to print an extra negative
1558 format!("{}{}", val as u128, self.ty_to_string())
1561 pub fn bit_width(&self) -> Option<usize> {
1563 IntTy::Isize => return None,
1573 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy)]
1584 pub fn ty_to_string(&self) -> &'static str {
1586 UintTy::Usize => "usize",
1588 UintTy::U16 => "u16",
1589 UintTy::U32 => "u32",
1590 UintTy::U64 => "u64",
1591 UintTy::U128 => "u128",
1595 pub fn to_symbol(&self) -> Symbol {
1597 UintTy::Usize => sym::usize,
1598 UintTy::U8 => sym::u8,
1599 UintTy::U16 => sym::u16,
1600 UintTy::U32 => sym::u32,
1601 UintTy::U64 => sym::u64,
1602 UintTy::U128 => sym::u128,
1606 pub fn val_to_string(&self, val: u128) -> String {
1607 format!("{}{}", val, self.ty_to_string())
1610 pub fn bit_width(&self) -> Option<usize> {
1612 UintTy::Usize => return None,
1617 UintTy::U128 => 128,
1622 impl fmt::Debug for UintTy {
1623 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1624 fmt::Display::fmt(self, f)
1628 impl fmt::Display for UintTy {
1629 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1630 write!(f, "{}", self.ty_to_string())
1634 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
1635 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
1636 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1637 pub struct AssocTyConstraint {
1640 pub kind: AssocTyConstraintKind,
1644 /// The kinds of an `AssocTyConstraint`.
1645 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1646 pub enum AssocTyConstraintKind {
1647 /// E.g., `A = Bar` in `Foo<A = Bar>`.
1651 /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
1653 bounds: GenericBounds,
1657 #[derive(Clone, RustcEncodable, RustcDecodable)]
1664 impl fmt::Debug for Ty {
1665 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1666 write!(f, "type({})", pprust::ty_to_string(self))
1670 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1671 pub struct BareFnTy {
1672 pub unsafety: Unsafety,
1674 pub generic_params: Vec<GenericParam>,
1675 pub decl: P<FnDecl>,
1678 /// The various kinds of type recognized by the compiler.
1679 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1681 /// A variable-length slice (`[T]`).
1683 /// A fixed length array (`[T; n]`).
1684 Array(P<Ty>, AnonConst),
1685 /// A raw pointer (`*const T` or `*mut T`).
1687 /// A reference (`&'a T` or `&'a mut T`).
1688 Rptr(Option<Lifetime>, MutTy),
1689 /// A bare function (e.g., `fn(usize) -> bool`).
1690 BareFn(P<BareFnTy>),
1691 /// The never type (`!`).
1693 /// A tuple (`(A, B, C, D,...)`).
1695 /// A path (`module::module::...::Type`), optionally
1696 /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
1698 /// Type parameters are stored in the `Path` itself.
1699 Path(Option<QSelf>, Path),
1700 /// A trait object type `Bound1 + Bound2 + Bound3`
1701 /// where `Bound` is a trait or a lifetime.
1702 TraitObject(GenericBounds, TraitObjectSyntax),
1703 /// An `impl Bound1 + Bound2 + Bound3` type
1704 /// where `Bound` is a trait or a lifetime.
1706 /// The `NodeId` exists to prevent lowering from having to
1707 /// generate `NodeId`s on the fly, which would complicate
1708 /// the generation of opaque `type Foo = impl Trait` items significantly.
1709 ImplTrait(NodeId, GenericBounds),
1710 /// No-op; kept solely so that we can pretty-print faithfully.
1714 /// This means the type should be inferred instead of it having been
1715 /// specified. This can appear anywhere in a type.
1717 /// Inferred type of a `self` or `&self` argument in a method.
1719 /// A macro in the type position.
1721 /// Placeholder for a kind that has failed to be defined.
1723 /// Placeholder for a `va_list`.
1728 pub fn is_implicit_self(&self) -> bool {
1729 if let TyKind::ImplicitSelf = *self {
1736 pub fn is_unit(&self) -> bool {
1737 if let TyKind::Tup(ref tys) = *self {
1745 /// Syntax used to declare a trait object.
1746 #[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1747 pub enum TraitObjectSyntax {
1752 /// Inline assembly dialect.
1754 /// E.g., `"intel"` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
1755 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
1756 pub enum AsmDialect {
1761 /// Inline assembly.
1763 /// E.g., `"={eax}"(result)` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
1764 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1765 pub struct InlineAsmOutput {
1766 pub constraint: Symbol,
1769 pub is_indirect: bool,
1772 /// Inline assembly.
1774 /// E.g., `asm!("NOP");`.
1775 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1776 pub struct InlineAsm {
1778 pub asm_str_style: StrStyle,
1779 pub outputs: Vec<InlineAsmOutput>,
1780 pub inputs: Vec<(Symbol, P<Expr>)>,
1781 pub clobbers: Vec<Symbol>,
1783 pub alignstack: bool,
1784 pub dialect: AsmDialect,
1785 pub ctxt: SyntaxContext,
1788 /// An argument in a function header.
1790 /// E.g., `bar: usize` as in `fn foo(bar: usize)`.
1791 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1793 pub attrs: ThinVec<Attribute>,
1800 /// Alternative representation for `Arg`s describing `self` parameter of methods.
1802 /// E.g., `&mut self` as in `fn foo(&mut self)`.
1803 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1805 /// `self`, `mut self`
1807 /// `&'lt self`, `&'lt mut self`
1808 Region(Option<Lifetime>, Mutability),
1809 /// `self: TYPE`, `mut self: TYPE`
1810 Explicit(P<Ty>, Mutability),
1813 pub type ExplicitSelf = Spanned<SelfKind>;
1816 pub fn to_self(&self) -> Option<ExplicitSelf> {
1817 if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.node {
1818 if ident.name == kw::SelfLower {
1819 return match self.ty.node {
1820 TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
1821 TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.node.is_implicit_self() => {
1822 Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
1825 self.pat.span.to(self.ty.span),
1826 SelfKind::Explicit(self.ty.clone(), mutbl),
1834 pub fn is_self(&self) -> bool {
1835 if let PatKind::Ident(_, ident, _) = self.pat.node {
1836 ident.name == kw::SelfLower
1842 pub fn from_self(attrs: ThinVec<Attribute>, eself: ExplicitSelf, eself_ident: Ident) -> Arg {
1843 let span = eself.span.to(eself_ident.span);
1844 let infer_ty = P(Ty {
1846 node: TyKind::ImplicitSelf,
1849 let arg = |mutbl, ty| Arg {
1853 node: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
1861 SelfKind::Explicit(ty, mutbl) => arg(mutbl, ty),
1862 SelfKind::Value(mutbl) => arg(mutbl, infer_ty),
1863 SelfKind::Region(lt, mutbl) => arg(
1864 Mutability::Immutable,
1881 /// A header (not the body) of a function declaration.
1883 /// E.g., `fn foo(bar: baz)`.
1884 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1886 pub inputs: Vec<Arg>,
1887 pub output: FunctionRetTy,
1888 pub c_variadic: bool,
1892 pub fn get_self(&self) -> Option<ExplicitSelf> {
1893 self.inputs.get(0).and_then(Arg::to_self)
1895 pub fn has_self(&self) -> bool {
1896 self.inputs.get(0).map(Arg::is_self).unwrap_or(false)
1900 /// Is the trait definition an auto trait?
1901 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1907 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1913 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
1917 return_impl_trait_id: NodeId,
1923 pub fn is_async(self) -> bool {
1924 if let IsAsync::Async { .. } = self {
1931 /// In ths case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
1932 pub fn opt_return_id(self) -> Option<NodeId> {
1935 return_impl_trait_id,
1937 } => Some(return_impl_trait_id),
1938 IsAsync::NotAsync => None,
1943 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1944 pub enum Constness {
1949 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
1950 pub enum Defaultness {
1955 impl fmt::Display for Unsafety {
1956 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1959 Unsafety::Normal => "normal",
1960 Unsafety::Unsafe => "unsafe",
1967 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
1968 pub enum ImplPolarity {
1969 /// `impl Trait for Type`
1971 /// `impl !Trait for Type`
1975 impl fmt::Debug for ImplPolarity {
1976 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1978 ImplPolarity::Positive => "positive".fmt(f),
1979 ImplPolarity::Negative => "negative".fmt(f),
1984 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
1985 pub enum FunctionRetTy {
1986 /// Returns type is not specified.
1988 /// Functions default to `()` and closures default to inference.
1989 /// Span points to where return type would be inserted.
1991 /// Everything else.
1995 impl FunctionRetTy {
1996 pub fn span(&self) -> Span {
1998 FunctionRetTy::Default(span) => span,
1999 FunctionRetTy::Ty(ref ty) => ty.span,
2004 /// Module declaration.
2006 /// E.g., `mod foo;` or `mod foo { .. }`.
2007 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2009 /// A span from the first token past `{` to the last token until `}`.
2010 /// For `mod foo;`, the inner span ranges from the first token
2011 /// to the last token in the external file.
2013 pub items: Vec<P<Item>>,
2014 /// `true` for `mod foo { .. }`; `false` for `mod foo;`.
2018 /// Foreign module declaration.
2020 /// E.g., `extern { .. }` or `extern C { .. }`.
2021 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2022 pub struct ForeignMod {
2024 pub items: Vec<ForeignItem>,
2027 /// Global inline assembly.
2029 /// Also known as "module-level assembly" or "file-scoped assembly".
2030 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
2031 pub struct GlobalAsm {
2033 pub ctxt: SyntaxContext,
2036 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2037 pub struct EnumDef {
2038 pub variants: Vec<Variant>,
2041 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2042 pub struct Variant {
2043 /// Name of the variant.
2045 /// Attributes of the variant.
2046 pub attrs: Vec<Attribute>,
2047 /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
2049 /// Fields and constructor id of the variant.
2050 pub data: VariantData,
2051 /// Explicit discriminant, e.g., `Foo = 1`.
2052 pub disr_expr: Option<AnonConst>,
2057 /// Part of `use` item to the right of its prefix.
2058 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2059 pub enum UseTreeKind {
2060 /// `use prefix` or `use prefix as rename`
2062 /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
2064 Simple(Option<Ident>, NodeId, NodeId),
2065 /// `use prefix::{...}`
2066 Nested(Vec<(UseTree, NodeId)>),
2071 /// A tree of paths sharing common prefixes.
2072 /// Used in `use` items both at top-level and inside of braces in import groups.
2073 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2074 pub struct UseTree {
2076 pub kind: UseTreeKind,
2081 pub fn ident(&self) -> Ident {
2083 UseTreeKind::Simple(Some(rename), ..) => rename,
2084 UseTreeKind::Simple(None, ..) => {
2088 .expect("empty prefix in a simple import")
2091 _ => panic!("`UseTree::ident` can only be used on a simple import"),
2096 /// Distinguishes between `Attribute`s that decorate items and Attributes that
2097 /// are contained as statements within items. These two cases need to be
2098 /// distinguished for pretty-printing.
2099 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
2100 pub enum AttrStyle {
2105 #[derive(Clone, PartialEq, Eq, Hash, Debug, PartialOrd, Ord, Copy)]
2106 pub struct AttrId(pub usize);
2108 impl Idx for AttrId {
2109 fn new(idx: usize) -> Self {
2112 fn index(self) -> usize {
2117 impl rustc_serialize::Encodable for AttrId {
2118 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
2123 impl rustc_serialize::Decodable for AttrId {
2124 fn decode<D: Decoder>(d: &mut D) -> Result<AttrId, D::Error> {
2125 d.read_nil().map(|_| crate::attr::mk_attr_id())
2129 /// Metadata associated with an item.
2130 /// Doc-comments are promoted to attributes that have `is_sugared_doc = true`.
2131 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2132 pub struct Attribute {
2134 pub style: AttrStyle,
2136 pub tokens: TokenStream,
2137 pub is_sugared_doc: bool,
2141 /// `TraitRef`s appear in impls.
2143 /// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
2144 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
2145 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
2146 /// same as the impl's `NodeId`).
2147 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2148 pub struct TraitRef {
2153 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2154 pub struct PolyTraitRef {
2155 /// The `'a` in `<'a> Foo<&'a T>`.
2156 pub bound_generic_params: Vec<GenericParam>,
2158 /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
2159 pub trait_ref: TraitRef,
2165 pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
2167 bound_generic_params: generic_params,
2168 trait_ref: TraitRef {
2170 ref_id: DUMMY_NODE_ID,
2177 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
2178 pub enum CrateSugar {
2179 /// Source is `pub(crate)`.
2182 /// Source is (just) `crate`.
2186 pub type Visibility = Spanned<VisibilityKind>;
2188 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2189 pub enum VisibilityKind {
2192 Restricted { path: P<Path>, id: NodeId },
2196 impl VisibilityKind {
2197 pub fn is_pub(&self) -> bool {
2198 if let VisibilityKind::Public = *self {
2206 /// Field of a struct.
2208 /// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
2209 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2210 pub struct StructField {
2212 pub ident: Option<Ident>,
2213 pub vis: Visibility,
2216 pub attrs: Vec<Attribute>,
2219 /// Fields and constructor ids of enum variants and structs.
2220 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2221 pub enum VariantData {
2224 /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
2225 Struct(Vec<StructField>, bool),
2228 /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
2229 Tuple(Vec<StructField>, NodeId),
2232 /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
2237 /// Return the fields of this variant.
2238 pub fn fields(&self) -> &[StructField] {
2240 VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
2245 /// Return the `NodeId` of this variant's constructor, if it has one.
2246 pub fn ctor_id(&self) -> Option<NodeId> {
2248 VariantData::Struct(..) => None,
2249 VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
2256 /// The name might be a dummy name in case of anonymous items.
2257 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2260 pub attrs: Vec<Attribute>,
2263 pub vis: Visibility,
2266 /// Original tokens this item was parsed from. This isn't necessarily
2267 /// available for all items, although over time more and more items should
2268 /// have this be `Some`. Right now this is primarily used for procedural
2269 /// macros, notably custom attributes.
2271 /// Note that the tokens here do not include the outer attributes, but will
2272 /// include inner attributes.
2273 pub tokens: Option<TokenStream>,
2277 /// Return the span that encompasses the attributes.
2278 pub fn span_with_attributes(&self) -> Span {
2279 self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
2283 /// A function header.
2285 /// All the information between the visibility and the name of the function is
2286 /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
2287 #[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)]
2288 pub struct FnHeader {
2289 pub unsafety: Unsafety,
2290 pub asyncness: Spanned<IsAsync>,
2291 pub constness: Spanned<Constness>,
2295 impl Default for FnHeader {
2296 fn default() -> FnHeader {
2298 unsafety: Unsafety::Normal,
2299 asyncness: dummy_spanned(IsAsync::NotAsync),
2300 constness: dummy_spanned(Constness::NotConst),
2306 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2308 /// An `extern crate` item, with optional *original* crate name if the crate was renamed.
2310 /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
2311 ExternCrate(Option<Name>),
2312 /// A use declaration (`use` or `pub use`) item.
2314 /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
2316 /// A static item (`static` or `pub static`).
2318 /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
2319 Static(P<Ty>, Mutability, P<Expr>),
2320 /// A constant item (`const` or `pub const`).
2322 /// E.g., `const FOO: i32 = 42;`.
2323 Const(P<Ty>, P<Expr>),
2324 /// A function declaration (`fn` or `pub fn`).
2326 /// E.g., `fn foo(bar: usize) -> usize { .. }`.
2327 Fn(P<FnDecl>, FnHeader, Generics, P<Block>),
2328 /// A module declaration (`mod` or `pub mod`).
2330 /// E.g., `mod foo;` or `mod foo { .. }`.
2332 /// An external module (`extern` or `pub extern`).
2334 /// E.g., `extern {}` or `extern "C" {}`.
2335 ForeignMod(ForeignMod),
2336 /// Module-level inline assembly (from `global_asm!()`).
2337 GlobalAsm(P<GlobalAsm>),
2338 /// A type alias (`type` or `pub type`).
2340 /// E.g., `type Foo = Bar<u8>;`.
2341 TyAlias(P<Ty>, Generics),
2342 /// An opaque `impl Trait` type alias.
2344 /// E.g., `type Foo = impl Bar + Boo;`.
2345 OpaqueTy(GenericBounds, Generics),
2346 /// An enum definition (`enum` or `pub enum`).
2348 /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
2349 Enum(EnumDef, Generics),
2350 /// A struct definition (`struct` or `pub struct`).
2352 /// E.g., `struct Foo<A> { x: A }`.
2353 Struct(VariantData, Generics),
2354 /// A union definition (`union` or `pub union`).
2356 /// E.g., `union Foo<A, B> { x: A, y: B }`.
2357 Union(VariantData, Generics),
2358 /// A Trait declaration (`trait` or `pub trait`).
2360 /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
2361 Trait(IsAuto, Unsafety, Generics, GenericBounds, Vec<TraitItem>),
2364 /// E.g., `trait Foo = Bar + Quux;`.
2365 TraitAlias(Generics, GenericBounds),
2366 /// An implementation.
2368 /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
2374 Option<TraitRef>, // (optional) trait this impl implements
2378 /// A macro invocation.
2380 /// E.g., `macro_rules! foo { .. }` or `foo!(..)`.
2383 /// A macro definition.
2388 pub fn descriptive_variant(&self) -> &str {
2390 ItemKind::ExternCrate(..) => "extern crate",
2391 ItemKind::Use(..) => "use",
2392 ItemKind::Static(..) => "static item",
2393 ItemKind::Const(..) => "constant item",
2394 ItemKind::Fn(..) => "function",
2395 ItemKind::Mod(..) => "module",
2396 ItemKind::ForeignMod(..) => "foreign module",
2397 ItemKind::GlobalAsm(..) => "global asm",
2398 ItemKind::TyAlias(..) => "type alias",
2399 ItemKind::OpaqueTy(..) => "opaque type",
2400 ItemKind::Enum(..) => "enum",
2401 ItemKind::Struct(..) => "struct",
2402 ItemKind::Union(..) => "union",
2403 ItemKind::Trait(..) => "trait",
2404 ItemKind::TraitAlias(..) => "trait alias",
2405 ItemKind::Mac(..) | ItemKind::MacroDef(..) | ItemKind::Impl(..) => "item",
2410 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2411 pub struct ForeignItem {
2413 pub attrs: Vec<Attribute>,
2414 pub node: ForeignItemKind,
2417 pub vis: Visibility,
2420 /// An item within an `extern` block.
2421 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
2422 pub enum ForeignItemKind {
2423 /// A foreign function.
2424 Fn(P<FnDecl>, Generics),
2425 /// A foreign static item (`static ext: u8`).
2426 Static(P<Ty>, Mutability),
2429 /// A macro invocation.
2433 impl ForeignItemKind {
2434 pub fn descriptive_variant(&self) -> &str {
2436 ForeignItemKind::Fn(..) => "foreign function",
2437 ForeignItemKind::Static(..) => "foreign static item",
2438 ForeignItemKind::Ty => "foreign type",
2439 ForeignItemKind::Macro(..) => "macro in foreign module",