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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /compiler/rustc_ast/src/ast.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_ast/src/ast.rs')
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1 files changed, 3051 insertions, 0 deletions
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+//! The Rust abstract syntax tree module.
+//!
+//! This module contains common structures forming the language AST.
+//! Two main entities in the module are [`Item`] (which represents an AST element with
+//! additional metadata), and [`ItemKind`] (which represents a concrete type and contains
+//! information specific to the type of the item).
+//!
+//! Other module items worth mentioning:
+//! - [`Ty`] and [`TyKind`]: A parsed Rust type.
+//! - [`Expr`] and [`ExprKind`]: A parsed Rust expression.
+//! - [`Pat`] and [`PatKind`]: A parsed Rust pattern. Patterns are often dual to expressions.
+//! - [`Stmt`] and [`StmtKind`]: An executable action that does not return a value.
+//! - [`FnDecl`], [`FnHeader`] and [`Param`]: Metadata associated with a function declaration.
+//! - [`Generics`], [`GenericParam`], [`WhereClause`]: Metadata associated with generic parameters.
+//! - [`EnumDef`] and [`Variant`]: Enum declaration.
+//! - [`Lit`] and [`LitKind`]: Literal expressions.
+//! - [`MacroDef`], [`MacStmtStyle`], [`MacCall`], [`MacDelimiter`]: Macro definition and invocation.
+//! - [`Attribute`]: Metadata associated with item.
+//! - [`UnOp`], [`BinOp`], and [`BinOpKind`]: Unary and binary operators.
+
+pub use crate::util::parser::ExprPrecedence;
+pub use GenericArgs::*;
+pub use UnsafeSource::*;
+
+use crate::ptr::P;
+use crate::token::{self, CommentKind, Delimiter};
+use crate::tokenstream::{DelimSpan, LazyTokenStream, TokenStream};
+
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::stack::ensure_sufficient_stack;
+use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::thin_vec::ThinVec;
+use rustc_macros::HashStable_Generic;
+use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
+use rustc_span::source_map::{respan, Spanned};
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
+use rustc_span::{Span, DUMMY_SP};
+
+use std::cmp::Ordering;
+use std::convert::TryFrom;
+use std::fmt;
+use std::mem;
+
+/// A "Label" is an identifier of some point in sources,
+/// e.g. in the following code:
+///
+/// ```rust
+/// 'outer: loop {
+/// break 'outer;
+/// }
+/// ```
+///
+/// `'outer` is a label.
+#[derive(Clone, Encodable, Decodable, Copy, HashStable_Generic, Eq, PartialEq)]
+pub struct Label {
+ pub ident: Ident,
+}
+
+impl fmt::Debug for Label {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "label({:?})", self.ident)
+ }
+}
+
+/// A "Lifetime" is an annotation of the scope in which variable
+/// can be used, e.g. `'a` in `&'a i32`.
+#[derive(Clone, Encodable, Decodable, Copy, PartialEq, Eq)]
+pub struct Lifetime {
+ pub id: NodeId,
+ pub ident: Ident,
+}
+
+impl fmt::Debug for Lifetime {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "lifetime({}: {})", self.id, self)
+ }
+}
+
+impl fmt::Display for Lifetime {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "{}", self.ident.name)
+ }
+}
+
+/// A "Path" is essentially Rust's notion of a name.
+///
+/// It's represented as a sequence of identifiers,
+/// along with a bunch of supporting information.
+///
+/// E.g., `std::cmp::PartialEq`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Path {
+ pub span: Span,
+ /// The segments in the path: the things separated by `::`.
+ /// Global paths begin with `kw::PathRoot`.
+ pub segments: Vec<PathSegment>,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+impl PartialEq<Symbol> for Path {
+ #[inline]
+ fn eq(&self, symbol: &Symbol) -> bool {
+ self.segments.len() == 1 && { self.segments[0].ident.name == *symbol }
+ }
+}
+
+impl<CTX: rustc_span::HashStableContext> HashStable<CTX> for Path {
+ fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
+ self.segments.len().hash_stable(hcx, hasher);
+ for segment in &self.segments {
+ segment.ident.hash_stable(hcx, hasher);
+ }
+ }
+}
+
+impl Path {
+ // Convert a span and an identifier to the corresponding
+ // one-segment path.
+ pub fn from_ident(ident: Ident) -> Path {
+ Path { segments: vec![PathSegment::from_ident(ident)], span: ident.span, tokens: None }
+ }
+
+ pub fn is_global(&self) -> bool {
+ !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
+ }
+}
+
+/// A segment of a path: an identifier, an optional lifetime, and a set of types.
+///
+/// E.g., `std`, `String` or `Box<T>`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct PathSegment {
+ /// The identifier portion of this path segment.
+ pub ident: Ident,
+
+ pub id: NodeId,
+
+ /// Type/lifetime parameters attached to this path. They come in
+ /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`.
+ /// `None` means that no parameter list is supplied (`Path`),
+ /// `Some` means that parameter list is supplied (`Path<X, Y>`)
+ /// but it can be empty (`Path<>`).
+ /// `P` is used as a size optimization for the common case with no parameters.
+ pub args: Option<P<GenericArgs>>,
+}
+
+impl PathSegment {
+ pub fn from_ident(ident: Ident) -> Self {
+ PathSegment { ident, id: DUMMY_NODE_ID, args: None }
+ }
+
+ pub fn path_root(span: Span) -> Self {
+ PathSegment::from_ident(Ident::new(kw::PathRoot, span))
+ }
+
+ pub fn span(&self) -> Span {
+ match &self.args {
+ Some(args) => self.ident.span.to(args.span()),
+ None => self.ident.span,
+ }
+ }
+}
+
+/// The arguments of a path segment.
+///
+/// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum GenericArgs {
+ /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
+ AngleBracketed(AngleBracketedArgs),
+ /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
+ Parenthesized(ParenthesizedArgs),
+}
+
+impl GenericArgs {
+ pub fn is_angle_bracketed(&self) -> bool {
+ matches!(self, AngleBracketed(..))
+ }
+
+ pub fn span(&self) -> Span {
+ match *self {
+ AngleBracketed(ref data) => data.span,
+ Parenthesized(ref data) => data.span,
+ }
+ }
+}
+
+/// Concrete argument in the sequence of generic args.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum GenericArg {
+ /// `'a` in `Foo<'a>`
+ Lifetime(Lifetime),
+ /// `Bar` in `Foo<Bar>`
+ Type(P<Ty>),
+ /// `1` in `Foo<1>`
+ Const(AnonConst),
+}
+
+impl GenericArg {
+ pub fn span(&self) -> Span {
+ match self {
+ GenericArg::Lifetime(lt) => lt.ident.span,
+ GenericArg::Type(ty) => ty.span,
+ GenericArg::Const(ct) => ct.value.span,
+ }
+ }
+}
+
+/// A path like `Foo<'a, T>`.
+#[derive(Clone, Encodable, Decodable, Debug, Default)]
+pub struct AngleBracketedArgs {
+ /// The overall span.
+ pub span: Span,
+ /// The comma separated parts in the `<...>`.
+ pub args: Vec<AngleBracketedArg>,
+}
+
+/// Either an argument for a parameter e.g., `'a`, `Vec<u8>`, `0`,
+/// or a constraint on an associated item, e.g., `Item = String` or `Item: Bound`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum AngleBracketedArg {
+ /// Argument for a generic parameter.
+ Arg(GenericArg),
+ /// Constraint for an associated item.
+ Constraint(AssocConstraint),
+}
+
+impl AngleBracketedArg {
+ pub fn span(&self) -> Span {
+ match self {
+ AngleBracketedArg::Arg(arg) => arg.span(),
+ AngleBracketedArg::Constraint(constraint) => constraint.span,
+ }
+ }
+}
+
+impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
+ fn into(self) -> Option<P<GenericArgs>> {
+ Some(P(GenericArgs::AngleBracketed(self)))
+ }
+}
+
+impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
+ fn into(self) -> Option<P<GenericArgs>> {
+ Some(P(GenericArgs::Parenthesized(self)))
+ }
+}
+
+/// A path like `Foo(A, B) -> C`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct ParenthesizedArgs {
+ /// ```text
+ /// Foo(A, B) -> C
+ /// ^^^^^^^^^^^^^^
+ /// ```
+ pub span: Span,
+
+ /// `(A, B)`
+ pub inputs: Vec<P<Ty>>,
+
+ /// ```text
+ /// Foo(A, B) -> C
+ /// ^^^^^^
+ /// ```
+ pub inputs_span: Span,
+
+ /// `C`
+ pub output: FnRetTy,
+}
+
+impl ParenthesizedArgs {
+ pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
+ let args = self
+ .inputs
+ .iter()
+ .cloned()
+ .map(|input| AngleBracketedArg::Arg(GenericArg::Type(input)))
+ .collect();
+ AngleBracketedArgs { span: self.inputs_span, args }
+ }
+}
+
+pub use crate::node_id::{NodeId, CRATE_NODE_ID, DUMMY_NODE_ID};
+
+/// A modifier on a bound, e.g., `?Trait` or `~const Trait`.
+///
+/// Negative bounds should also be handled here.
+#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug)]
+pub enum TraitBoundModifier {
+ /// No modifiers
+ None,
+
+ /// `?Trait`
+ Maybe,
+
+ /// `~const Trait`
+ MaybeConst,
+
+ /// `~const ?Trait`
+ //
+ // This parses but will be rejected during AST validation.
+ MaybeConstMaybe,
+}
+
+/// The AST represents all type param bounds as types.
+/// `typeck::collect::compute_bounds` matches these against
+/// the "special" built-in traits (see `middle::lang_items`) and
+/// detects `Copy`, `Send` and `Sync`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum GenericBound {
+ Trait(PolyTraitRef, TraitBoundModifier),
+ Outlives(Lifetime),
+}
+
+impl GenericBound {
+ pub fn span(&self) -> Span {
+ match self {
+ GenericBound::Trait(ref t, ..) => t.span,
+ GenericBound::Outlives(ref l) => l.ident.span,
+ }
+ }
+}
+
+pub type GenericBounds = Vec<GenericBound>;
+
+/// Specifies the enforced ordering for generic parameters. In the future,
+/// if we wanted to relax this order, we could override `PartialEq` and
+/// `PartialOrd`, to allow the kinds to be unordered.
+#[derive(Hash, Clone, Copy)]
+pub enum ParamKindOrd {
+ Lifetime,
+ Type,
+ Const,
+ // `Infer` is not actually constructed directly from the AST, but is implicitly constructed
+ // during HIR lowering, and `ParamKindOrd` will implicitly order inferred variables last.
+ Infer,
+}
+
+impl Ord for ParamKindOrd {
+ fn cmp(&self, other: &Self) -> Ordering {
+ use ParamKindOrd::*;
+ let to_int = |v| match v {
+ Lifetime => 0,
+ Infer | Type | Const => 1,
+ };
+
+ to_int(*self).cmp(&to_int(*other))
+ }
+}
+impl PartialOrd for ParamKindOrd {
+ fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+ Some(self.cmp(other))
+ }
+}
+impl PartialEq for ParamKindOrd {
+ fn eq(&self, other: &Self) -> bool {
+ self.cmp(other) == Ordering::Equal
+ }
+}
+impl Eq for ParamKindOrd {}
+
+impl fmt::Display for ParamKindOrd {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self {
+ ParamKindOrd::Lifetime => "lifetime".fmt(f),
+ ParamKindOrd::Type => "type".fmt(f),
+ ParamKindOrd::Const { .. } => "const".fmt(f),
+ ParamKindOrd::Infer => "infer".fmt(f),
+ }
+ }
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum GenericParamKind {
+ /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
+ Lifetime,
+ Type {
+ default: Option<P<Ty>>,
+ },
+ Const {
+ ty: P<Ty>,
+ /// Span of the `const` keyword.
+ kw_span: Span,
+ /// Optional default value for the const generic param
+ default: Option<AnonConst>,
+ },
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct GenericParam {
+ pub id: NodeId,
+ pub ident: Ident,
+ pub attrs: AttrVec,
+ pub bounds: GenericBounds,
+ pub is_placeholder: bool,
+ pub kind: GenericParamKind,
+ pub colon_span: Option<Span>,
+}
+
+impl GenericParam {
+ pub fn span(&self) -> Span {
+ match &self.kind {
+ GenericParamKind::Lifetime | GenericParamKind::Type { default: None } => {
+ self.ident.span
+ }
+ GenericParamKind::Type { default: Some(ty) } => self.ident.span.to(ty.span),
+ GenericParamKind::Const { kw_span, default: Some(default), .. } => {
+ kw_span.to(default.value.span)
+ }
+ GenericParamKind::Const { kw_span, default: None, ty } => kw_span.to(ty.span),
+ }
+ }
+}
+
+/// Represents lifetime, type and const parameters attached to a declaration of
+/// a function, enum, trait, etc.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Generics {
+ pub params: Vec<GenericParam>,
+ pub where_clause: WhereClause,
+ pub span: Span,
+}
+
+impl Default for Generics {
+ /// Creates an instance of `Generics`.
+ fn default() -> Generics {
+ Generics {
+ params: Vec::new(),
+ where_clause: WhereClause {
+ has_where_token: false,
+ predicates: Vec::new(),
+ span: DUMMY_SP,
+ },
+ span: DUMMY_SP,
+ }
+ }
+}
+
+/// A where-clause in a definition.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct WhereClause {
+ /// `true` if we ate a `where` token: this can happen
+ /// if we parsed no predicates (e.g. `struct Foo where {}`).
+ /// This allows us to pretty-print accurately.
+ pub has_where_token: bool,
+ pub predicates: Vec<WherePredicate>,
+ pub span: Span,
+}
+
+/// A single predicate in a where-clause.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum WherePredicate {
+ /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
+ BoundPredicate(WhereBoundPredicate),
+ /// A lifetime predicate (e.g., `'a: 'b + 'c`).
+ RegionPredicate(WhereRegionPredicate),
+ /// An equality predicate (unsupported).
+ EqPredicate(WhereEqPredicate),
+}
+
+impl WherePredicate {
+ pub fn span(&self) -> Span {
+ match self {
+ WherePredicate::BoundPredicate(p) => p.span,
+ WherePredicate::RegionPredicate(p) => p.span,
+ WherePredicate::EqPredicate(p) => p.span,
+ }
+ }
+}
+
+/// A type bound.
+///
+/// E.g., `for<'c> Foo: Send + Clone + 'c`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct WhereBoundPredicate {
+ pub span: Span,
+ /// Any generics from a `for` binding.
+ pub bound_generic_params: Vec<GenericParam>,
+ /// The type being bounded.
+ pub bounded_ty: P<Ty>,
+ /// Trait and lifetime bounds (`Clone + Send + 'static`).
+ pub bounds: GenericBounds,
+}
+
+/// A lifetime predicate.
+///
+/// E.g., `'a: 'b + 'c`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct WhereRegionPredicate {
+ pub span: Span,
+ pub lifetime: Lifetime,
+ pub bounds: GenericBounds,
+}
+
+/// An equality predicate (unsupported).
+///
+/// E.g., `T = int`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct WhereEqPredicate {
+ pub id: NodeId,
+ pub span: Span,
+ pub lhs_ty: P<Ty>,
+ pub rhs_ty: P<Ty>,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Crate {
+ pub attrs: Vec<Attribute>,
+ pub items: Vec<P<Item>>,
+ pub spans: ModSpans,
+ /// Must be equal to `CRATE_NODE_ID` after the crate root is expanded, but may hold
+ /// expansion placeholders or an unassigned value (`DUMMY_NODE_ID`) before that.
+ pub id: NodeId,
+ pub is_placeholder: bool,
+}
+
+/// Possible values inside of compile-time attribute lists.
+///
+/// E.g., the '..' in `#[name(..)]`.
+#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum NestedMetaItem {
+ /// A full MetaItem, for recursive meta items.
+ MetaItem(MetaItem),
+ /// A literal.
+ ///
+ /// E.g., `"foo"`, `64`, `true`.
+ Literal(Lit),
+}
+
+/// A spanned compile-time attribute item.
+///
+/// E.g., `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`.
+#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+pub struct MetaItem {
+ pub path: Path,
+ pub kind: MetaItemKind,
+ pub span: Span,
+}
+
+/// A compile-time attribute item.
+///
+/// E.g., `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`.
+#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum MetaItemKind {
+ /// Word meta item.
+ ///
+ /// E.g., `test` as in `#[test]`.
+ Word,
+ /// List meta item.
+ ///
+ /// E.g., `derive(..)` as in `#[derive(..)]`.
+ List(Vec<NestedMetaItem>),
+ /// Name value meta item.
+ ///
+ /// E.g., `feature = "foo"` as in `#[feature = "foo"]`.
+ NameValue(Lit),
+}
+
+/// A block (`{ .. }`).
+///
+/// E.g., `{ .. }` as in `fn foo() { .. }`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Block {
+ /// The statements in the block.
+ pub stmts: Vec<Stmt>,
+ pub id: NodeId,
+ /// Distinguishes between `unsafe { ... }` and `{ ... }`.
+ pub rules: BlockCheckMode,
+ pub span: Span,
+ pub tokens: Option<LazyTokenStream>,
+ /// The following *isn't* a parse error, but will cause multiple errors in following stages.
+ /// ```compile_fail
+ /// let x = {
+ /// foo: var
+ /// };
+ /// ```
+ /// #34255
+ pub could_be_bare_literal: bool,
+}
+
+/// A match pattern.
+///
+/// Patterns appear in match statements and some other contexts, such as `let` and `if let`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Pat {
+ pub id: NodeId,
+ pub kind: PatKind,
+ pub span: Span,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+impl Pat {
+ /// Attempt reparsing the pattern as a type.
+ /// This is intended for use by diagnostics.
+ pub fn to_ty(&self) -> Option<P<Ty>> {
+ let kind = match &self.kind {
+ // In a type expression `_` is an inference variable.
+ PatKind::Wild => TyKind::Infer,
+ // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
+ PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
+ TyKind::Path(None, Path::from_ident(*ident))
+ }
+ PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
+ PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
+ // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
+ PatKind::Ref(pat, mutbl) => {
+ pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
+ }
+ // A slice/array pattern `[P]` can be reparsed as `[T]`, an unsized array,
+ // when `P` can be reparsed as a type `T`.
+ PatKind::Slice(pats) if pats.len() == 1 => pats[0].to_ty().map(TyKind::Slice)?,
+ // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
+ // assuming `T0` to `Tn` are all syntactically valid as types.
+ PatKind::Tuple(pats) => {
+ let mut tys = Vec::with_capacity(pats.len());
+ // FIXME(#48994) - could just be collected into an Option<Vec>
+ for pat in pats {
+ tys.push(pat.to_ty()?);
+ }
+ TyKind::Tup(tys)
+ }
+ _ => return None,
+ };
+
+ Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
+ }
+
+ /// Walk top-down and call `it` in each place where a pattern occurs
+ /// starting with the root pattern `walk` is called on. If `it` returns
+ /// false then we will descend no further but siblings will be processed.
+ pub fn walk(&self, it: &mut impl FnMut(&Pat) -> bool) {
+ if !it(self) {
+ return;
+ }
+
+ match &self.kind {
+ // Walk into the pattern associated with `Ident` (if any).
+ PatKind::Ident(_, _, Some(p)) => p.walk(it),
+
+ // Walk into each field of struct.
+ PatKind::Struct(_, _, fields, _) => fields.iter().for_each(|field| field.pat.walk(it)),
+
+ // Sequence of patterns.
+ PatKind::TupleStruct(_, _, s)
+ | PatKind::Tuple(s)
+ | PatKind::Slice(s)
+ | PatKind::Or(s) => s.iter().for_each(|p| p.walk(it)),
+
+ // Trivial wrappers over inner patterns.
+ PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
+
+ // These patterns do not contain subpatterns, skip.
+ PatKind::Wild
+ | PatKind::Rest
+ | PatKind::Lit(_)
+ | PatKind::Range(..)
+ | PatKind::Ident(..)
+ | PatKind::Path(..)
+ | PatKind::MacCall(_) => {}
+ }
+ }
+
+ /// Is this a `..` pattern?
+ pub fn is_rest(&self) -> bool {
+ matches!(self.kind, PatKind::Rest)
+ }
+}
+
+/// A single field in a struct pattern.
+///
+/// Patterns like the fields of `Foo { x, ref y, ref mut z }`
+/// are treated the same as `x: x, y: ref y, z: ref mut z`,
+/// except when `is_shorthand` is true.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct PatField {
+ /// The identifier for the field.
+ pub ident: Ident,
+ /// The pattern the field is destructured to.
+ pub pat: P<Pat>,
+ pub is_shorthand: bool,
+ pub attrs: AttrVec,
+ pub id: NodeId,
+ pub span: Span,
+ pub is_placeholder: bool,
+}
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
+pub enum BindingMode {
+ ByRef(Mutability),
+ ByValue(Mutability),
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum RangeEnd {
+ /// `..=` or `...`
+ Included(RangeSyntax),
+ /// `..`
+ Excluded,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum RangeSyntax {
+ /// `...`
+ DotDotDot,
+ /// `..=`
+ DotDotEq,
+}
+
+/// All the different flavors of pattern that Rust recognizes.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum PatKind {
+ /// Represents a wildcard pattern (`_`).
+ Wild,
+
+ /// A `PatKind::Ident` may either be a new bound variable (`ref mut binding @ OPT_SUBPATTERN`),
+ /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
+ /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
+ /// during name resolution.
+ Ident(BindingMode, Ident, Option<P<Pat>>),
+
+ /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
+ /// The `bool` is `true` in the presence of a `..`.
+ Struct(Option<QSelf>, Path, Vec<PatField>, /* recovered */ bool),
+
+ /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
+ TupleStruct(Option<QSelf>, Path, Vec<P<Pat>>),
+
+ /// An or-pattern `A | B | C`.
+ /// Invariant: `pats.len() >= 2`.
+ Or(Vec<P<Pat>>),
+
+ /// A possibly qualified path pattern.
+ /// Unqualified path patterns `A::B::C` can legally refer to variants, structs, constants
+ /// or associated constants. Qualified path patterns `<A>::B::C`/`<A as Trait>::B::C` can
+ /// only legally refer to associated constants.
+ Path(Option<QSelf>, Path),
+
+ /// A tuple pattern (`(a, b)`).
+ Tuple(Vec<P<Pat>>),
+
+ /// A `box` pattern.
+ Box(P<Pat>),
+
+ /// A reference pattern (e.g., `&mut (a, b)`).
+ Ref(P<Pat>, Mutability),
+
+ /// A literal.
+ Lit(P<Expr>),
+
+ /// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
+ Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
+
+ /// A slice pattern `[a, b, c]`.
+ Slice(Vec<P<Pat>>),
+
+ /// A rest pattern `..`.
+ ///
+ /// Syntactically it is valid anywhere.
+ ///
+ /// Semantically however, it only has meaning immediately inside:
+ /// - a slice pattern: `[a, .., b]`,
+ /// - a binding pattern immediately inside a slice pattern: `[a, r @ ..]`,
+ /// - a tuple pattern: `(a, .., b)`,
+ /// - a tuple struct/variant pattern: `$path(a, .., b)`.
+ ///
+ /// In all of these cases, an additional restriction applies,
+ /// only one rest pattern may occur in the pattern sequences.
+ Rest,
+
+ /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
+ Paren(P<Pat>),
+
+ /// A macro pattern; pre-expansion.
+ MacCall(MacCall),
+}
+
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
+#[derive(HashStable_Generic, Encodable, Decodable)]
+pub enum Mutability {
+ Mut,
+ Not,
+}
+
+impl Mutability {
+ pub fn invert(self) -> Self {
+ match self {
+ Mutability::Mut => Mutability::Not,
+ Mutability::Not => Mutability::Mut,
+ }
+ }
+
+ pub fn prefix_str(&self) -> &'static str {
+ match self {
+ Mutability::Mut => "mut ",
+ Mutability::Not => "",
+ }
+ }
+}
+
+/// The kind of borrow in an `AddrOf` expression,
+/// e.g., `&place` or `&raw const place`.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
+pub enum BorrowKind {
+ /// A normal borrow, `&$expr` or `&mut $expr`.
+ /// The resulting type is either `&'a T` or `&'a mut T`
+ /// where `T = typeof($expr)` and `'a` is some lifetime.
+ Ref,
+ /// A raw borrow, `&raw const $expr` or `&raw mut $expr`.
+ /// The resulting type is either `*const T` or `*mut T`
+ /// where `T = typeof($expr)`.
+ Raw,
+}
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
+pub enum BinOpKind {
+ /// The `+` operator (addition)
+ Add,
+ /// The `-` operator (subtraction)
+ Sub,
+ /// The `*` operator (multiplication)
+ Mul,
+ /// The `/` operator (division)
+ Div,
+ /// The `%` operator (modulus)
+ Rem,
+ /// The `&&` operator (logical and)
+ And,
+ /// The `||` operator (logical or)
+ Or,
+ /// The `^` operator (bitwise xor)
+ BitXor,
+ /// The `&` operator (bitwise and)
+ BitAnd,
+ /// The `|` operator (bitwise or)
+ BitOr,
+ /// The `<<` operator (shift left)
+ Shl,
+ /// The `>>` operator (shift right)
+ Shr,
+ /// The `==` operator (equality)
+ Eq,
+ /// The `<` operator (less than)
+ Lt,
+ /// The `<=` operator (less than or equal to)
+ Le,
+ /// The `!=` operator (not equal to)
+ Ne,
+ /// The `>=` operator (greater than or equal to)
+ Ge,
+ /// The `>` operator (greater than)
+ Gt,
+}
+
+impl BinOpKind {
+ pub fn to_string(&self) -> &'static str {
+ use BinOpKind::*;
+ match *self {
+ Add => "+",
+ Sub => "-",
+ Mul => "*",
+ Div => "/",
+ Rem => "%",
+ And => "&&",
+ Or => "||",
+ BitXor => "^",
+ BitAnd => "&",
+ BitOr => "|",
+ Shl => "<<",
+ Shr => ">>",
+ Eq => "==",
+ Lt => "<",
+ Le => "<=",
+ Ne => "!=",
+ Ge => ">=",
+ Gt => ">",
+ }
+ }
+ pub fn lazy(&self) -> bool {
+ matches!(self, BinOpKind::And | BinOpKind::Or)
+ }
+
+ pub fn is_comparison(&self) -> bool {
+ use BinOpKind::*;
+ // Note for developers: please keep this as is;
+ // we want compilation to fail if another variant is added.
+ match *self {
+ Eq | Lt | Le | Ne | Gt | Ge => true,
+ And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
+ }
+ }
+}
+
+pub type BinOp = Spanned<BinOpKind>;
+
+/// Unary operator.
+///
+/// Note that `&data` is not an operator, it's an `AddrOf` expression.
+#[derive(Clone, Encodable, Decodable, Debug, Copy)]
+pub enum UnOp {
+ /// The `*` operator for dereferencing
+ Deref,
+ /// The `!` operator for logical inversion
+ Not,
+ /// The `-` operator for negation
+ Neg,
+}
+
+impl UnOp {
+ pub fn to_string(op: UnOp) -> &'static str {
+ match op {
+ UnOp::Deref => "*",
+ UnOp::Not => "!",
+ UnOp::Neg => "-",
+ }
+ }
+}
+
+/// A statement
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Stmt {
+ pub id: NodeId,
+ pub kind: StmtKind,
+ pub span: Span,
+}
+
+impl Stmt {
+ pub fn has_trailing_semicolon(&self) -> bool {
+ match &self.kind {
+ StmtKind::Semi(_) => true,
+ StmtKind::MacCall(mac) => matches!(mac.style, MacStmtStyle::Semicolon),
+ _ => false,
+ }
+ }
+
+ /// Converts a parsed `Stmt` to a `Stmt` with
+ /// a trailing semicolon.
+ ///
+ /// This only modifies the parsed AST struct, not the attached
+ /// `LazyTokenStream`. The parser is responsible for calling
+ /// `CreateTokenStream::add_trailing_semi` when there is actually
+ /// a semicolon in the tokenstream.
+ pub fn add_trailing_semicolon(mut self) -> Self {
+ self.kind = match self.kind {
+ StmtKind::Expr(expr) => StmtKind::Semi(expr),
+ StmtKind::MacCall(mac) => {
+ StmtKind::MacCall(mac.map(|MacCallStmt { mac, style: _, attrs, tokens }| {
+ MacCallStmt { mac, style: MacStmtStyle::Semicolon, attrs, tokens }
+ }))
+ }
+ kind => kind,
+ };
+
+ self
+ }
+
+ pub fn is_item(&self) -> bool {
+ matches!(self.kind, StmtKind::Item(_))
+ }
+
+ pub fn is_expr(&self) -> bool {
+ matches!(self.kind, StmtKind::Expr(_))
+ }
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum StmtKind {
+ /// A local (let) binding.
+ Local(P<Local>),
+ /// An item definition.
+ Item(P<Item>),
+ /// Expr without trailing semi-colon.
+ Expr(P<Expr>),
+ /// Expr with a trailing semi-colon.
+ Semi(P<Expr>),
+ /// Just a trailing semi-colon.
+ Empty,
+ /// Macro.
+ MacCall(P<MacCallStmt>),
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct MacCallStmt {
+ pub mac: MacCall,
+ pub style: MacStmtStyle,
+ pub attrs: AttrVec,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
+pub enum MacStmtStyle {
+ /// The macro statement had a trailing semicolon (e.g., `foo! { ... };`
+ /// `foo!(...);`, `foo![...];`).
+ Semicolon,
+ /// The macro statement had braces (e.g., `foo! { ... }`).
+ Braces,
+ /// The macro statement had parentheses or brackets and no semicolon (e.g.,
+ /// `foo!(...)`). All of these will end up being converted into macro
+ /// expressions.
+ NoBraces,
+}
+
+/// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Local {
+ pub id: NodeId,
+ pub pat: P<Pat>,
+ pub ty: Option<P<Ty>>,
+ pub kind: LocalKind,
+ pub span: Span,
+ pub attrs: AttrVec,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum LocalKind {
+ /// Local declaration.
+ /// Example: `let x;`
+ Decl,
+ /// Local declaration with an initializer.
+ /// Example: `let x = y;`
+ Init(P<Expr>),
+ /// Local declaration with an initializer and an `else` clause.
+ /// Example: `let Some(x) = y else { return };`
+ InitElse(P<Expr>, P<Block>),
+}
+
+impl LocalKind {
+ pub fn init(&self) -> Option<&Expr> {
+ match self {
+ Self::Decl => None,
+ Self::Init(i) | Self::InitElse(i, _) => Some(i),
+ }
+ }
+
+ pub fn init_else_opt(&self) -> Option<(&Expr, Option<&Block>)> {
+ match self {
+ Self::Decl => None,
+ Self::Init(init) => Some((init, None)),
+ Self::InitElse(init, els) => Some((init, Some(els))),
+ }
+ }
+}
+
+/// An arm of a 'match'.
+///
+/// E.g., `0..=10 => { println!("match!") }` as in
+///
+/// ```
+/// match 123 {
+/// 0..=10 => { println!("match!") },
+/// _ => { println!("no match!") },
+/// }
+/// ```
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Arm {
+ pub attrs: AttrVec,
+ /// Match arm pattern, e.g. `10` in `match foo { 10 => {}, _ => {} }`
+ pub pat: P<Pat>,
+ /// Match arm guard, e.g. `n > 10` in `match foo { n if n > 10 => {}, _ => {} }`
+ pub guard: Option<P<Expr>>,
+ /// Match arm body.
+ pub body: P<Expr>,
+ pub span: Span,
+ pub id: NodeId,
+ pub is_placeholder: bool,
+}
+
+/// A single field in a struct expression, e.g. `x: value` and `y` in `Foo { x: value, y }`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct ExprField {
+ pub attrs: AttrVec,
+ pub id: NodeId,
+ pub span: Span,
+ pub ident: Ident,
+ pub expr: P<Expr>,
+ pub is_shorthand: bool,
+ pub is_placeholder: bool,
+}
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
+pub enum BlockCheckMode {
+ Default,
+ Unsafe(UnsafeSource),
+}
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
+pub enum UnsafeSource {
+ CompilerGenerated,
+ UserProvided,
+}
+
+/// A constant (expression) that's not an item or associated item,
+/// but needs its own `DefId` for type-checking, const-eval, etc.
+/// These are usually found nested inside types (e.g., array lengths)
+/// or expressions (e.g., repeat counts), and also used to define
+/// explicit discriminant values for enum variants.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct AnonConst {
+ pub id: NodeId,
+ pub value: P<Expr>,
+}
+
+/// An expression.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Expr {
+ pub id: NodeId,
+ pub kind: ExprKind,
+ pub span: Span,
+ pub attrs: AttrVec,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+impl Expr {
+ /// Returns `true` if this expression would be valid somewhere that expects a value;
+ /// for example, an `if` condition.
+ pub fn returns(&self) -> bool {
+ if let ExprKind::Block(ref block, _) = self.kind {
+ match block.stmts.last().map(|last_stmt| &last_stmt.kind) {
+ // Implicit return
+ Some(StmtKind::Expr(_)) => true,
+ // Last statement is an explicit return?
+ Some(StmtKind::Semi(expr)) => matches!(expr.kind, ExprKind::Ret(_)),
+ // This is a block that doesn't end in either an implicit or explicit return.
+ _ => false,
+ }
+ } else {
+ // This is not a block, it is a value.
+ true
+ }
+ }
+
+ /// Is this expr either `N`, or `{ N }`.
+ ///
+ /// If this is not the case, name resolution does not resolve `N` when using
+ /// `min_const_generics` as more complex expressions are not supported.
+ pub fn is_potential_trivial_const_param(&self) -> bool {
+ let this = if let ExprKind::Block(ref block, None) = self.kind {
+ if block.stmts.len() == 1 {
+ if let StmtKind::Expr(ref expr) = block.stmts[0].kind { expr } else { self }
+ } else {
+ self
+ }
+ } else {
+ self
+ };
+
+ if let ExprKind::Path(None, ref path) = this.kind {
+ if path.segments.len() == 1 && path.segments[0].args.is_none() {
+ return true;
+ }
+ }
+
+ false
+ }
+
+ pub fn to_bound(&self) -> Option<GenericBound> {
+ match &self.kind {
+ ExprKind::Path(None, path) => Some(GenericBound::Trait(
+ PolyTraitRef::new(Vec::new(), path.clone(), self.span),
+ TraitBoundModifier::None,
+ )),
+ _ => None,
+ }
+ }
+
+ pub fn peel_parens(&self) -> &Expr {
+ let mut expr = self;
+ while let ExprKind::Paren(inner) = &expr.kind {
+ expr = &inner;
+ }
+ expr
+ }
+
+ /// Attempts to reparse as `Ty` (for diagnostic purposes).
+ pub fn to_ty(&self) -> Option<P<Ty>> {
+ let kind = match &self.kind {
+ // Trivial conversions.
+ ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
+ ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
+
+ ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
+
+ ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
+ expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
+ }
+
+ ExprKind::Repeat(expr, expr_len) => {
+ expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?
+ }
+
+ ExprKind::Array(exprs) if exprs.len() == 1 => exprs[0].to_ty().map(TyKind::Slice)?,
+
+ ExprKind::Tup(exprs) => {
+ let tys = exprs.iter().map(|expr| expr.to_ty()).collect::<Option<Vec<_>>>()?;
+ TyKind::Tup(tys)
+ }
+
+ // If binary operator is `Add` and both `lhs` and `rhs` are trait bounds,
+ // then type of result is trait object.
+ // Otherwise we don't assume the result type.
+ ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
+ if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
+ TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
+ } else {
+ return None;
+ }
+ }
+
+ ExprKind::Underscore => TyKind::Infer,
+
+ // This expression doesn't look like a type syntactically.
+ _ => return None,
+ };
+
+ Some(P(Ty { kind, id: self.id, span: self.span, tokens: None }))
+ }
+
+ pub fn precedence(&self) -> ExprPrecedence {
+ match self.kind {
+ ExprKind::Box(_) => ExprPrecedence::Box,
+ ExprKind::Array(_) => ExprPrecedence::Array,
+ ExprKind::ConstBlock(_) => ExprPrecedence::ConstBlock,
+ ExprKind::Call(..) => ExprPrecedence::Call,
+ ExprKind::MethodCall(..) => ExprPrecedence::MethodCall,
+ ExprKind::Tup(_) => ExprPrecedence::Tup,
+ ExprKind::Binary(op, ..) => ExprPrecedence::Binary(op.node),
+ ExprKind::Unary(..) => ExprPrecedence::Unary,
+ ExprKind::Lit(_) => ExprPrecedence::Lit,
+ ExprKind::Type(..) | ExprKind::Cast(..) => ExprPrecedence::Cast,
+ ExprKind::Let(..) => ExprPrecedence::Let,
+ ExprKind::If(..) => ExprPrecedence::If,
+ ExprKind::While(..) => ExprPrecedence::While,
+ ExprKind::ForLoop(..) => ExprPrecedence::ForLoop,
+ ExprKind::Loop(..) => ExprPrecedence::Loop,
+ ExprKind::Match(..) => ExprPrecedence::Match,
+ ExprKind::Closure(..) => ExprPrecedence::Closure,
+ ExprKind::Block(..) => ExprPrecedence::Block,
+ ExprKind::TryBlock(..) => ExprPrecedence::TryBlock,
+ ExprKind::Async(..) => ExprPrecedence::Async,
+ ExprKind::Await(..) => ExprPrecedence::Await,
+ ExprKind::Assign(..) => ExprPrecedence::Assign,
+ ExprKind::AssignOp(..) => ExprPrecedence::AssignOp,
+ ExprKind::Field(..) => ExprPrecedence::Field,
+ ExprKind::Index(..) => ExprPrecedence::Index,
+ ExprKind::Range(..) => ExprPrecedence::Range,
+ ExprKind::Underscore => ExprPrecedence::Path,
+ ExprKind::Path(..) => ExprPrecedence::Path,
+ ExprKind::AddrOf(..) => ExprPrecedence::AddrOf,
+ ExprKind::Break(..) => ExprPrecedence::Break,
+ ExprKind::Continue(..) => ExprPrecedence::Continue,
+ ExprKind::Ret(..) => ExprPrecedence::Ret,
+ ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
+ ExprKind::MacCall(..) => ExprPrecedence::Mac,
+ ExprKind::Struct(..) => ExprPrecedence::Struct,
+ ExprKind::Repeat(..) => ExprPrecedence::Repeat,
+ ExprKind::Paren(..) => ExprPrecedence::Paren,
+ ExprKind::Try(..) => ExprPrecedence::Try,
+ ExprKind::Yield(..) => ExprPrecedence::Yield,
+ ExprKind::Yeet(..) => ExprPrecedence::Yeet,
+ ExprKind::Err => ExprPrecedence::Err,
+ }
+ }
+
+ pub fn take(&mut self) -> Self {
+ mem::replace(
+ self,
+ Expr {
+ id: DUMMY_NODE_ID,
+ kind: ExprKind::Err,
+ span: DUMMY_SP,
+ attrs: ThinVec::new(),
+ tokens: None,
+ },
+ )
+ }
+
+ // To a first-order approximation, is this a pattern
+ pub fn is_approximately_pattern(&self) -> bool {
+ match &self.peel_parens().kind {
+ ExprKind::Box(_)
+ | ExprKind::Array(_)
+ | ExprKind::Call(_, _)
+ | ExprKind::Tup(_)
+ | ExprKind::Lit(_)
+ | ExprKind::Range(_, _, _)
+ | ExprKind::Underscore
+ | ExprKind::Path(_, _)
+ | ExprKind::Struct(_) => true,
+ _ => false,
+ }
+ }
+}
+
+/// Limit types of a range (inclusive or exclusive)
+#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug)]
+pub enum RangeLimits {
+ /// Inclusive at the beginning, exclusive at the end
+ HalfOpen,
+ /// Inclusive at the beginning and end
+ Closed,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum StructRest {
+ /// `..x`.
+ Base(P<Expr>),
+ /// `..`.
+ Rest(Span),
+ /// No trailing `..` or expression.
+ None,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct StructExpr {
+ pub qself: Option<QSelf>,
+ pub path: Path,
+ pub fields: Vec<ExprField>,
+ pub rest: StructRest,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum ExprKind {
+ /// A `box x` expression.
+ Box(P<Expr>),
+ /// An array (`[a, b, c, d]`)
+ Array(Vec<P<Expr>>),
+ /// Allow anonymous constants from an inline `const` block
+ ConstBlock(AnonConst),
+ /// A function call
+ ///
+ /// The first field resolves to the function itself,
+ /// and the second field is the list of arguments.
+ /// This also represents calling the constructor of
+ /// tuple-like ADTs such as tuple structs and enum variants.
+ Call(P<Expr>, Vec<P<Expr>>),
+ /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
+ ///
+ /// The `PathSegment` represents the method name and its generic arguments
+ /// (within the angle brackets).
+ /// The first element of the vector of an `Expr` is the expression that evaluates
+ /// to the object on which the method is being called on (the receiver),
+ /// and the remaining elements are the rest of the arguments.
+ /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
+ /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
+ /// This `Span` is the span of the function, without the dot and receiver
+ /// (e.g. `foo(a, b)` in `x.foo(a, b)`
+ MethodCall(PathSegment, Vec<P<Expr>>, Span),
+ /// A tuple (e.g., `(a, b, c, d)`).
+ Tup(Vec<P<Expr>>),
+ /// A binary operation (e.g., `a + b`, `a * b`).
+ Binary(BinOp, P<Expr>, P<Expr>),
+ /// A unary operation (e.g., `!x`, `*x`).
+ Unary(UnOp, P<Expr>),
+ /// A literal (e.g., `1`, `"foo"`).
+ Lit(Lit),
+ /// A cast (e.g., `foo as f64`).
+ Cast(P<Expr>, P<Ty>),
+ /// A type ascription (e.g., `42: usize`).
+ Type(P<Expr>, P<Ty>),
+ /// A `let pat = expr` expression that is only semantically allowed in the condition
+ /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
+ ///
+ /// `Span` represents the whole `let pat = expr` statement.
+ Let(P<Pat>, P<Expr>, Span),
+ /// An `if` block, with an optional `else` block.
+ ///
+ /// `if expr { block } else { expr }`
+ If(P<Expr>, P<Block>, Option<P<Expr>>),
+ /// A while loop, with an optional label.
+ ///
+ /// `'label: while expr { block }`
+ While(P<Expr>, P<Block>, Option<Label>),
+ /// A `for` loop, with an optional label.
+ ///
+ /// `'label: for pat in expr { block }`
+ ///
+ /// This is desugared to a combination of `loop` and `match` expressions.
+ ForLoop(P<Pat>, P<Expr>, P<Block>, Option<Label>),
+ /// Conditionless loop (can be exited with `break`, `continue`, or `return`).
+ ///
+ /// `'label: loop { block }`
+ Loop(P<Block>, Option<Label>),
+ /// A `match` block.
+ Match(P<Expr>, Vec<Arm>),
+ /// A closure (e.g., `move |a, b, c| a + b + c`).
+ ///
+ /// The final span is the span of the argument block `|...|`.
+ Closure(ClosureBinder, CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
+ /// A block (`'label: { ... }`).
+ Block(P<Block>, Option<Label>),
+ /// An async block (`async move { ... }`).
+ ///
+ /// The `NodeId` is the `NodeId` for the closure that results from
+ /// desugaring an async block, just like the NodeId field in the
+ /// `Async::Yes` variant. This is necessary in order to create a def for the
+ /// closure which can be used as a parent of any child defs. Defs
+ /// created during lowering cannot be made the parent of any other
+ /// preexisting defs.
+ Async(CaptureBy, NodeId, P<Block>),
+ /// An await expression (`my_future.await`).
+ Await(P<Expr>),
+
+ /// A try block (`try { ... }`).
+ TryBlock(P<Block>),
+
+ /// An assignment (`a = foo()`).
+ /// The `Span` argument is the span of the `=` token.
+ Assign(P<Expr>, P<Expr>, Span),
+ /// An assignment with an operator.
+ ///
+ /// E.g., `a += 1`.
+ AssignOp(BinOp, P<Expr>, P<Expr>),
+ /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.
+ Field(P<Expr>, Ident),
+ /// An indexing operation (e.g., `foo[2]`).
+ Index(P<Expr>, P<Expr>),
+ /// A range (e.g., `1..2`, `1..`, `..2`, `1..=2`, `..=2`; and `..` in destructuring assignment).
+ Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
+ /// An underscore, used in destructuring assignment to ignore a value.
+ Underscore,
+
+ /// Variable reference, possibly containing `::` and/or type
+ /// parameters (e.g., `foo::bar::<baz>`).
+ ///
+ /// Optionally "qualified" (e.g., `<Vec<T> as SomeTrait>::SomeType`).
+ Path(Option<QSelf>, Path),
+
+ /// A referencing operation (`&a`, `&mut a`, `&raw const a` or `&raw mut a`).
+ AddrOf(BorrowKind, Mutability, P<Expr>),
+ /// A `break`, with an optional label to break, and an optional expression.
+ Break(Option<Label>, Option<P<Expr>>),
+ /// A `continue`, with an optional label.
+ Continue(Option<Label>),
+ /// A `return`, with an optional value to be returned.
+ Ret(Option<P<Expr>>),
+
+ /// Output of the `asm!()` macro.
+ InlineAsm(P<InlineAsm>),
+
+ /// A macro invocation; pre-expansion.
+ MacCall(MacCall),
+
+ /// A struct literal expression.
+ ///
+ /// E.g., `Foo {x: 1, y: 2}`, or `Foo {x: 1, .. rest}`.
+ Struct(P<StructExpr>),
+
+ /// An array literal constructed from one repeated element.
+ ///
+ /// E.g., `[1; 5]`. The expression is the element to be
+ /// repeated; the constant is the number of times to repeat it.
+ Repeat(P<Expr>, AnonConst),
+
+ /// No-op: used solely so we can pretty-print faithfully.
+ Paren(P<Expr>),
+
+ /// A try expression (`expr?`).
+ Try(P<Expr>),
+
+ /// A `yield`, with an optional value to be yielded.
+ Yield(Option<P<Expr>>),
+
+ /// A `do yeet` (aka `throw`/`fail`/`bail`/`raise`/whatever),
+ /// with an optional value to be returned.
+ Yeet(Option<P<Expr>>),
+
+ /// Placeholder for an expression that wasn't syntactically well formed in some way.
+ Err,
+}
+
+/// The explicit `Self` type in a "qualified path". The actual
+/// path, including the trait and the associated item, is stored
+/// separately. `position` represents the index of the associated
+/// item qualified with this `Self` type.
+///
+/// ```ignore (only-for-syntax-highlight)
+/// <Vec<T> as a::b::Trait>::AssociatedItem
+/// ^~~~~ ~~~~~~~~~~~~~~^
+/// ty position = 3
+///
+/// <Vec<T>>::AssociatedItem
+/// ^~~~~ ^
+/// ty position = 0
+/// ```
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct QSelf {
+ pub ty: P<Ty>,
+
+ /// The span of `a::b::Trait` in a path like `<Vec<T> as
+ /// a::b::Trait>::AssociatedItem`; in the case where `position ==
+ /// 0`, this is an empty span.
+ pub path_span: Span,
+ pub position: usize,
+}
+
+/// A capture clause used in closures and `async` blocks.
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum CaptureBy {
+ /// `move |x| y + x`.
+ Value,
+ /// `move` keyword was not specified.
+ Ref,
+}
+
+/// The movability of a generator / closure literal:
+/// whether a generator contains self-references, causing it to be `!Unpin`.
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable, Debug, Copy)]
+#[derive(HashStable_Generic)]
+pub enum Movability {
+ /// May contain self-references, `!Unpin`.
+ Static,
+ /// Must not contain self-references, `Unpin`.
+ Movable,
+}
+
+/// Closure lifetime binder, `for<'a, 'b>` in `for<'a, 'b> |_: &'a (), _: &'b ()|`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum ClosureBinder {
+ /// The binder is not present, all closure lifetimes are inferred.
+ NotPresent,
+ /// The binder is present.
+ For {
+ /// Span of the whole `for<>` clause
+ ///
+ /// ```text
+ /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
+ /// ^^^^^^^^^^^ -- this
+ /// ```
+ span: Span,
+
+ /// Lifetimes in the `for<>` closure
+ ///
+ /// ```text
+ /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
+ /// ^^^^^^ -- this
+ /// ```
+ generic_params: P<[GenericParam]>,
+ },
+}
+
+/// Represents a macro invocation. The `path` indicates which macro
+/// is being invoked, and the `args` are arguments passed to it.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct MacCall {
+ pub path: Path,
+ pub args: P<MacArgs>,
+ pub prior_type_ascription: Option<(Span, bool)>,
+}
+
+impl MacCall {
+ pub fn span(&self) -> Span {
+ self.path.span.to(self.args.span().unwrap_or(self.path.span))
+ }
+}
+
+/// Arguments passed to an attribute or a function-like macro.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum MacArgs {
+ /// No arguments - `#[attr]`.
+ Empty,
+ /// Delimited arguments - `#[attr()/[]/{}]` or `mac!()/[]/{}`.
+ Delimited(DelimSpan, MacDelimiter, TokenStream),
+ /// Arguments of a key-value attribute - `#[attr = "value"]`.
+ Eq(
+ /// Span of the `=` token.
+ Span,
+ /// The "value".
+ MacArgsEq,
+ ),
+}
+
+// The RHS of a `MacArgs::Eq` starts out as an expression. Once macro expansion
+// is completed, all cases end up either as a literal, which is the form used
+// after lowering to HIR, or as an error.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum MacArgsEq {
+ Ast(P<Expr>),
+ Hir(Lit),
+}
+
+impl MacArgs {
+ pub fn delim(&self) -> Option<Delimiter> {
+ match self {
+ MacArgs::Delimited(_, delim, _) => Some(delim.to_token()),
+ MacArgs::Empty | MacArgs::Eq(..) => None,
+ }
+ }
+
+ pub fn span(&self) -> Option<Span> {
+ match self {
+ MacArgs::Empty => None,
+ MacArgs::Delimited(dspan, ..) => Some(dspan.entire()),
+ MacArgs::Eq(eq_span, MacArgsEq::Ast(expr)) => Some(eq_span.to(expr.span)),
+ MacArgs::Eq(_, MacArgsEq::Hir(lit)) => {
+ unreachable!("in literal form when getting span: {:?}", lit);
+ }
+ }
+ }
+
+ /// Tokens inside the delimiters or after `=`.
+ /// Proc macros see these tokens, for example.
+ pub fn inner_tokens(&self) -> TokenStream {
+ match self {
+ MacArgs::Empty => TokenStream::default(),
+ MacArgs::Delimited(.., tokens) => tokens.clone(),
+ MacArgs::Eq(_, MacArgsEq::Ast(expr)) => TokenStream::from_ast(expr),
+ MacArgs::Eq(_, MacArgsEq::Hir(lit)) => {
+ unreachable!("in literal form when getting inner tokens: {:?}", lit)
+ }
+ }
+ }
+
+ /// Whether a macro with these arguments needs a semicolon
+ /// when used as a standalone item or statement.
+ pub fn need_semicolon(&self) -> bool {
+ !matches!(self, MacArgs::Delimited(_, MacDelimiter::Brace, _))
+ }
+}
+
+impl<CTX> HashStable<CTX> for MacArgs
+where
+ CTX: crate::HashStableContext,
+{
+ fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
+ mem::discriminant(self).hash_stable(ctx, hasher);
+ match self {
+ MacArgs::Empty => {}
+ MacArgs::Delimited(dspan, delim, tokens) => {
+ dspan.hash_stable(ctx, hasher);
+ delim.hash_stable(ctx, hasher);
+ tokens.hash_stable(ctx, hasher);
+ }
+ MacArgs::Eq(_eq_span, MacArgsEq::Ast(expr)) => {
+ unreachable!("hash_stable {:?}", expr);
+ }
+ MacArgs::Eq(eq_span, MacArgsEq::Hir(lit)) => {
+ eq_span.hash_stable(ctx, hasher);
+ lit.hash_stable(ctx, hasher);
+ }
+ }
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum MacDelimiter {
+ Parenthesis,
+ Bracket,
+ Brace,
+}
+
+impl MacDelimiter {
+ pub fn to_token(self) -> Delimiter {
+ match self {
+ MacDelimiter::Parenthesis => Delimiter::Parenthesis,
+ MacDelimiter::Bracket => Delimiter::Bracket,
+ MacDelimiter::Brace => Delimiter::Brace,
+ }
+ }
+
+ pub fn from_token(delim: Delimiter) -> Option<MacDelimiter> {
+ match delim {
+ Delimiter::Parenthesis => Some(MacDelimiter::Parenthesis),
+ Delimiter::Bracket => Some(MacDelimiter::Bracket),
+ Delimiter::Brace => Some(MacDelimiter::Brace),
+ Delimiter::Invisible => None,
+ }
+ }
+}
+
+/// Represents a macro definition.
+#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+pub struct MacroDef {
+ pub body: P<MacArgs>,
+ /// `true` if macro was defined with `macro_rules`.
+ pub macro_rules: bool,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
+#[derive(HashStable_Generic)]
+pub enum StrStyle {
+ /// A regular string, like `"foo"`.
+ Cooked,
+ /// A raw string, like `r##"foo"##`.
+ ///
+ /// The value is the number of `#` symbols used.
+ Raw(u8),
+}
+
+/// An AST literal.
+#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+pub struct Lit {
+ /// The original literal token as written in source code.
+ pub token: token::Lit,
+ /// The "semantic" representation of the literal lowered from the original tokens.
+ /// Strings are unescaped, hexadecimal forms are eliminated, etc.
+ /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
+ pub kind: LitKind,
+ pub span: Span,
+}
+
+/// Same as `Lit`, but restricted to string literals.
+#[derive(Clone, Copy, Encodable, Decodable, Debug)]
+pub struct StrLit {
+ /// The original literal token as written in source code.
+ pub style: StrStyle,
+ pub symbol: Symbol,
+ pub suffix: Option<Symbol>,
+ pub span: Span,
+ /// The unescaped "semantic" representation of the literal lowered from the original token.
+ /// FIXME: Remove this and only create the semantic representation during lowering to HIR.
+ pub symbol_unescaped: Symbol,
+}
+
+impl StrLit {
+ pub fn as_lit(&self) -> Lit {
+ let token_kind = match self.style {
+ StrStyle::Cooked => token::Str,
+ StrStyle::Raw(n) => token::StrRaw(n),
+ };
+ Lit {
+ token: token::Lit::new(token_kind, self.symbol, self.suffix),
+ span: self.span,
+ kind: LitKind::Str(self.symbol_unescaped, self.style),
+ }
+ }
+}
+
+/// Type of the integer literal based on provided suffix.
+#[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
+#[derive(HashStable_Generic)]
+pub enum LitIntType {
+ /// e.g. `42_i32`.
+ Signed(IntTy),
+ /// e.g. `42_u32`.
+ Unsigned(UintTy),
+ /// e.g. `42`.
+ Unsuffixed,
+}
+
+/// Type of the float literal based on provided suffix.
+#[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
+#[derive(HashStable_Generic)]
+pub enum LitFloatType {
+ /// A float literal with a suffix (`1f32` or `1E10f32`).
+ Suffixed(FloatTy),
+ /// A float literal without a suffix (`1.0 or 1.0E10`).
+ Unsuffixed,
+}
+
+/// Literal kind.
+///
+/// E.g., `"foo"`, `42`, `12.34`, or `bool`.
+#[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
+pub enum LitKind {
+ /// A string literal (`"foo"`).
+ Str(Symbol, StrStyle),
+ /// A byte string (`b"foo"`).
+ ByteStr(Lrc<[u8]>),
+ /// A byte char (`b'f'`).
+ Byte(u8),
+ /// A character literal (`'a'`).
+ Char(char),
+ /// An integer literal (`1`).
+ Int(u128, LitIntType),
+ /// A float literal (`1f64` or `1E10f64`).
+ Float(Symbol, LitFloatType),
+ /// A boolean literal.
+ Bool(bool),
+ /// Placeholder for a literal that wasn't well-formed in some way.
+ Err(Symbol),
+}
+
+impl LitKind {
+ /// Returns `true` if this literal is a string.
+ pub fn is_str(&self) -> bool {
+ matches!(self, LitKind::Str(..))
+ }
+
+ /// Returns `true` if this literal is byte literal string.
+ pub fn is_bytestr(&self) -> bool {
+ matches!(self, LitKind::ByteStr(_))
+ }
+
+ /// Returns `true` if this is a numeric literal.
+ pub fn is_numeric(&self) -> bool {
+ matches!(self, LitKind::Int(..) | LitKind::Float(..))
+ }
+
+ /// Returns `true` if this literal has no suffix.
+ /// Note: this will return true for literals with prefixes such as raw strings and byte strings.
+ pub fn is_unsuffixed(&self) -> bool {
+ !self.is_suffixed()
+ }
+
+ /// Returns `true` if this literal has a suffix.
+ pub fn is_suffixed(&self) -> bool {
+ match *self {
+ // suffixed variants
+ LitKind::Int(_, LitIntType::Signed(..) | LitIntType::Unsigned(..))
+ | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
+ // unsuffixed variants
+ LitKind::Str(..)
+ | LitKind::ByteStr(..)
+ | LitKind::Byte(..)
+ | LitKind::Char(..)
+ | LitKind::Int(_, LitIntType::Unsuffixed)
+ | LitKind::Float(_, LitFloatType::Unsuffixed)
+ | LitKind::Bool(..)
+ | LitKind::Err(..) => false,
+ }
+ }
+}
+
+// N.B., If you change this, you'll probably want to change the corresponding
+// type structure in `middle/ty.rs` as well.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct MutTy {
+ pub ty: P<Ty>,
+ pub mutbl: Mutability,
+}
+
+/// Represents a function's signature in a trait declaration,
+/// trait implementation, or free function.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct FnSig {
+ pub header: FnHeader,
+ pub decl: P<FnDecl>,
+ pub span: Span,
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
+pub enum FloatTy {
+ F32,
+ F64,
+}
+
+impl FloatTy {
+ pub fn name_str(self) -> &'static str {
+ match self {
+ FloatTy::F32 => "f32",
+ FloatTy::F64 => "f64",
+ }
+ }
+
+ pub fn name(self) -> Symbol {
+ match self {
+ FloatTy::F32 => sym::f32,
+ FloatTy::F64 => sym::f64,
+ }
+ }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
+pub enum IntTy {
+ Isize,
+ I8,
+ I16,
+ I32,
+ I64,
+ I128,
+}
+
+impl IntTy {
+ pub fn name_str(&self) -> &'static str {
+ match *self {
+ IntTy::Isize => "isize",
+ IntTy::I8 => "i8",
+ IntTy::I16 => "i16",
+ IntTy::I32 => "i32",
+ IntTy::I64 => "i64",
+ IntTy::I128 => "i128",
+ }
+ }
+
+ pub fn name(&self) -> Symbol {
+ match *self {
+ IntTy::Isize => sym::isize,
+ IntTy::I8 => sym::i8,
+ IntTy::I16 => sym::i16,
+ IntTy::I32 => sym::i32,
+ IntTy::I64 => sym::i64,
+ IntTy::I128 => sym::i128,
+ }
+ }
+}
+
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
+pub enum UintTy {
+ Usize,
+ U8,
+ U16,
+ U32,
+ U64,
+ U128,
+}
+
+impl UintTy {
+ pub fn name_str(&self) -> &'static str {
+ match *self {
+ UintTy::Usize => "usize",
+ UintTy::U8 => "u8",
+ UintTy::U16 => "u16",
+ UintTy::U32 => "u32",
+ UintTy::U64 => "u64",
+ UintTy::U128 => "u128",
+ }
+ }
+
+ pub fn name(&self) -> Symbol {
+ match *self {
+ UintTy::Usize => sym::usize,
+ UintTy::U8 => sym::u8,
+ UintTy::U16 => sym::u16,
+ UintTy::U32 => sym::u32,
+ UintTy::U64 => sym::u64,
+ UintTy::U128 => sym::u128,
+ }
+ }
+}
+
+/// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
+/// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct AssocConstraint {
+ pub id: NodeId,
+ pub ident: Ident,
+ pub gen_args: Option<GenericArgs>,
+ pub kind: AssocConstraintKind,
+ pub span: Span,
+}
+
+/// The kinds of an `AssocConstraint`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum Term {
+ Ty(P<Ty>),
+ Const(AnonConst),
+}
+
+impl From<P<Ty>> for Term {
+ fn from(v: P<Ty>) -> Self {
+ Term::Ty(v)
+ }
+}
+
+impl From<AnonConst> for Term {
+ fn from(v: AnonConst) -> Self {
+ Term::Const(v)
+ }
+}
+
+/// The kinds of an `AssocConstraint`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum AssocConstraintKind {
+ /// E.g., `A = Bar`, `A = 3` in `Foo<A = Bar>` where A is an associated type.
+ Equality { term: Term },
+ /// E.g. `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`.
+ Bound { bounds: GenericBounds },
+}
+
+#[derive(Encodable, Decodable, Debug)]
+pub struct Ty {
+ pub id: NodeId,
+ pub kind: TyKind,
+ pub span: Span,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+impl Clone for Ty {
+ fn clone(&self) -> Self {
+ ensure_sufficient_stack(|| Self {
+ id: self.id,
+ kind: self.kind.clone(),
+ span: self.span,
+ tokens: self.tokens.clone(),
+ })
+ }
+}
+
+impl Ty {
+ pub fn peel_refs(&self) -> &Self {
+ let mut final_ty = self;
+ while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
+ final_ty = &ty;
+ }
+ final_ty
+ }
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct BareFnTy {
+ pub unsafety: Unsafe,
+ pub ext: Extern,
+ pub generic_params: Vec<GenericParam>,
+ pub decl: P<FnDecl>,
+ /// Span of the `fn(...) -> ...` part.
+ pub decl_span: Span,
+}
+
+/// The various kinds of type recognized by the compiler.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum TyKind {
+ /// A variable-length slice (`[T]`).
+ Slice(P<Ty>),
+ /// A fixed length array (`[T; n]`).
+ Array(P<Ty>, AnonConst),
+ /// A raw pointer (`*const T` or `*mut T`).
+ Ptr(MutTy),
+ /// A reference (`&'a T` or `&'a mut T`).
+ Rptr(Option<Lifetime>, MutTy),
+ /// A bare function (e.g., `fn(usize) -> bool`).
+ BareFn(P<BareFnTy>),
+ /// The never type (`!`).
+ Never,
+ /// A tuple (`(A, B, C, D,...)`).
+ Tup(Vec<P<Ty>>),
+ /// A path (`module::module::...::Type`), optionally
+ /// "qualified", e.g., `<Vec<T> as SomeTrait>::SomeType`.
+ ///
+ /// Type parameters are stored in the `Path` itself.
+ Path(Option<QSelf>, Path),
+ /// A trait object type `Bound1 + Bound2 + Bound3`
+ /// where `Bound` is a trait or a lifetime.
+ TraitObject(GenericBounds, TraitObjectSyntax),
+ /// An `impl Bound1 + Bound2 + Bound3` type
+ /// where `Bound` is a trait or a lifetime.
+ ///
+ /// The `NodeId` exists to prevent lowering from having to
+ /// generate `NodeId`s on the fly, which would complicate
+ /// the generation of opaque `type Foo = impl Trait` items significantly.
+ ImplTrait(NodeId, GenericBounds),
+ /// No-op; kept solely so that we can pretty-print faithfully.
+ Paren(P<Ty>),
+ /// Unused for now.
+ Typeof(AnonConst),
+ /// This means the type should be inferred instead of it having been
+ /// specified. This can appear anywhere in a type.
+ Infer,
+ /// Inferred type of a `self` or `&self` argument in a method.
+ ImplicitSelf,
+ /// A macro in the type position.
+ MacCall(MacCall),
+ /// Placeholder for a kind that has failed to be defined.
+ Err,
+ /// Placeholder for a `va_list`.
+ CVarArgs,
+}
+
+impl TyKind {
+ pub fn is_implicit_self(&self) -> bool {
+ matches!(self, TyKind::ImplicitSelf)
+ }
+
+ pub fn is_unit(&self) -> bool {
+ matches!(self, TyKind::Tup(tys) if tys.is_empty())
+ }
+
+ pub fn is_simple_path(&self) -> Option<Symbol> {
+ if let TyKind::Path(None, Path { segments, .. }) = &self && segments.len() == 1 {
+ Some(segments[0].ident.name)
+ } else {
+ None
+ }
+ }
+}
+
+/// Syntax used to declare a trait object.
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum TraitObjectSyntax {
+ Dyn,
+ None,
+}
+
+/// Inline assembly operand explicit register or register class.
+///
+/// E.g., `"eax"` as in `asm!("mov eax, 2", out("eax") result)`.
+#[derive(Clone, Copy, Encodable, Decodable, Debug)]
+pub enum InlineAsmRegOrRegClass {
+ Reg(Symbol),
+ RegClass(Symbol),
+}
+
+bitflags::bitflags! {
+ #[derive(Encodable, Decodable, HashStable_Generic)]
+ pub struct InlineAsmOptions: u16 {
+ const PURE = 1 << 0;
+ const NOMEM = 1 << 1;
+ const READONLY = 1 << 2;
+ const PRESERVES_FLAGS = 1 << 3;
+ const NORETURN = 1 << 4;
+ const NOSTACK = 1 << 5;
+ const ATT_SYNTAX = 1 << 6;
+ const RAW = 1 << 7;
+ const MAY_UNWIND = 1 << 8;
+ }
+}
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
+pub enum InlineAsmTemplatePiece {
+ String(String),
+ Placeholder { operand_idx: usize, modifier: Option<char>, span: Span },
+}
+
+impl fmt::Display for InlineAsmTemplatePiece {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self {
+ Self::String(s) => {
+ for c in s.chars() {
+ match c {
+ '{' => f.write_str("{{")?,
+ '}' => f.write_str("}}")?,
+ _ => c.fmt(f)?,
+ }
+ }
+ Ok(())
+ }
+ Self::Placeholder { operand_idx, modifier: Some(modifier), .. } => {
+ write!(f, "{{{}:{}}}", operand_idx, modifier)
+ }
+ Self::Placeholder { operand_idx, modifier: None, .. } => {
+ write!(f, "{{{}}}", operand_idx)
+ }
+ }
+ }
+}
+
+impl InlineAsmTemplatePiece {
+ /// Rebuilds the asm template string from its pieces.
+ pub fn to_string(s: &[Self]) -> String {
+ use fmt::Write;
+ let mut out = String::new();
+ for p in s.iter() {
+ let _ = write!(out, "{}", p);
+ }
+ out
+ }
+}
+
+/// Inline assembly symbol operands get their own AST node that is somewhat
+/// similar to `AnonConst`.
+///
+/// The main difference is that we specifically don't assign it `DefId` in
+/// `DefCollector`. Instead this is deferred until AST lowering where we
+/// lower it to an `AnonConst` (for functions) or a `Path` (for statics)
+/// depending on what the path resolves to.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct InlineAsmSym {
+ pub id: NodeId,
+ pub qself: Option<QSelf>,
+ pub path: Path,
+}
+
+/// Inline assembly operand.
+///
+/// E.g., `out("eax") result` as in `asm!("mov eax, 2", out("eax") result)`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum InlineAsmOperand {
+ In {
+ reg: InlineAsmRegOrRegClass,
+ expr: P<Expr>,
+ },
+ Out {
+ reg: InlineAsmRegOrRegClass,
+ late: bool,
+ expr: Option<P<Expr>>,
+ },
+ InOut {
+ reg: InlineAsmRegOrRegClass,
+ late: bool,
+ expr: P<Expr>,
+ },
+ SplitInOut {
+ reg: InlineAsmRegOrRegClass,
+ late: bool,
+ in_expr: P<Expr>,
+ out_expr: Option<P<Expr>>,
+ },
+ Const {
+ anon_const: AnonConst,
+ },
+ Sym {
+ sym: InlineAsmSym,
+ },
+}
+
+/// Inline assembly.
+///
+/// E.g., `asm!("NOP");`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct InlineAsm {
+ pub template: Vec<InlineAsmTemplatePiece>,
+ pub template_strs: Box<[(Symbol, Option<Symbol>, Span)]>,
+ pub operands: Vec<(InlineAsmOperand, Span)>,
+ pub clobber_abis: Vec<(Symbol, Span)>,
+ pub options: InlineAsmOptions,
+ pub line_spans: Vec<Span>,
+}
+
+/// A parameter in a function header.
+///
+/// E.g., `bar: usize` as in `fn foo(bar: usize)`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Param {
+ pub attrs: AttrVec,
+ pub ty: P<Ty>,
+ pub pat: P<Pat>,
+ pub id: NodeId,
+ pub span: Span,
+ pub is_placeholder: bool,
+}
+
+/// Alternative representation for `Arg`s describing `self` parameter of methods.
+///
+/// E.g., `&mut self` as in `fn foo(&mut self)`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum SelfKind {
+ /// `self`, `mut self`
+ Value(Mutability),
+ /// `&'lt self`, `&'lt mut self`
+ Region(Option<Lifetime>, Mutability),
+ /// `self: TYPE`, `mut self: TYPE`
+ Explicit(P<Ty>, Mutability),
+}
+
+pub type ExplicitSelf = Spanned<SelfKind>;
+
+impl Param {
+ /// Attempts to cast parameter to `ExplicitSelf`.
+ pub fn to_self(&self) -> Option<ExplicitSelf> {
+ if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
+ if ident.name == kw::SelfLower {
+ return match self.ty.kind {
+ TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
+ TyKind::Rptr(lt, MutTy { ref ty, mutbl }) if ty.kind.is_implicit_self() => {
+ Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
+ }
+ _ => Some(respan(
+ self.pat.span.to(self.ty.span),
+ SelfKind::Explicit(self.ty.clone(), mutbl),
+ )),
+ };
+ }
+ }
+ None
+ }
+
+ /// Returns `true` if parameter is `self`.
+ pub fn is_self(&self) -> bool {
+ if let PatKind::Ident(_, ident, _) = self.pat.kind {
+ ident.name == kw::SelfLower
+ } else {
+ false
+ }
+ }
+
+ /// Builds a `Param` object from `ExplicitSelf`.
+ pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
+ let span = eself.span.to(eself_ident.span);
+ let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
+ let param = |mutbl, ty| Param {
+ attrs,
+ pat: P(Pat {
+ id: DUMMY_NODE_ID,
+ kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
+ span,
+ tokens: None,
+ }),
+ span,
+ ty,
+ id: DUMMY_NODE_ID,
+ is_placeholder: false,
+ };
+ match eself.node {
+ SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
+ SelfKind::Value(mutbl) => param(mutbl, infer_ty),
+ SelfKind::Region(lt, mutbl) => param(
+ Mutability::Not,
+ P(Ty {
+ id: DUMMY_NODE_ID,
+ kind: TyKind::Rptr(lt, MutTy { ty: infer_ty, mutbl }),
+ span,
+ tokens: None,
+ }),
+ ),
+ }
+ }
+}
+
+/// A signature (not the body) of a function declaration.
+///
+/// E.g., `fn foo(bar: baz)`.
+///
+/// Please note that it's different from `FnHeader` structure
+/// which contains metadata about function safety, asyncness, constness and ABI.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct FnDecl {
+ pub inputs: Vec<Param>,
+ pub output: FnRetTy,
+}
+
+impl FnDecl {
+ pub fn has_self(&self) -> bool {
+ self.inputs.get(0).map_or(false, Param::is_self)
+ }
+ pub fn c_variadic(&self) -> bool {
+ self.inputs.last().map_or(false, |arg| matches!(arg.ty.kind, TyKind::CVarArgs))
+ }
+}
+
+/// Is the trait definition an auto trait?
+#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum IsAuto {
+ Yes,
+ No,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
+#[derive(HashStable_Generic)]
+pub enum Unsafe {
+ Yes(Span),
+ No,
+}
+
+#[derive(Copy, Clone, Encodable, Decodable, Debug)]
+pub enum Async {
+ Yes { span: Span, closure_id: NodeId, return_impl_trait_id: NodeId },
+ No,
+}
+
+impl Async {
+ pub fn is_async(self) -> bool {
+ matches!(self, Async::Yes { .. })
+ }
+
+ /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
+ pub fn opt_return_id(self) -> Option<NodeId> {
+ match self {
+ Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
+ Async::No => None,
+ }
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)]
+#[derive(HashStable_Generic)]
+pub enum Const {
+ Yes(Span),
+ No,
+}
+
+/// Item defaultness.
+/// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
+#[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum Defaultness {
+ Default(Span),
+ Final,
+}
+
+#[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
+pub enum ImplPolarity {
+ /// `impl Trait for Type`
+ Positive,
+ /// `impl !Trait for Type`
+ Negative(Span),
+}
+
+impl fmt::Debug for ImplPolarity {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match *self {
+ ImplPolarity::Positive => "positive".fmt(f),
+ ImplPolarity::Negative(_) => "negative".fmt(f),
+ }
+ }
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum FnRetTy {
+ /// Returns type is not specified.
+ ///
+ /// Functions default to `()` and closures default to inference.
+ /// Span points to where return type would be inserted.
+ Default(Span),
+ /// Everything else.
+ Ty(P<Ty>),
+}
+
+impl FnRetTy {
+ pub fn span(&self) -> Span {
+ match *self {
+ FnRetTy::Default(span) => span,
+ FnRetTy::Ty(ref ty) => ty.span,
+ }
+ }
+}
+
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
+pub enum Inline {
+ Yes,
+ No,
+}
+
+/// Module item kind.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum ModKind {
+ /// Module with inlined definition `mod foo { ... }`,
+ /// or with definition outlined to a separate file `mod foo;` and already loaded from it.
+ /// The inner span is from the first token past `{` to the last token until `}`,
+ /// or from the first to the last token in the loaded file.
+ Loaded(Vec<P<Item>>, Inline, ModSpans),
+ /// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
+ Unloaded,
+}
+
+#[derive(Copy, Clone, Encodable, Decodable, Debug)]
+pub struct ModSpans {
+ /// `inner_span` covers the body of the module; for a file module, its the whole file.
+ /// For an inline module, its the span inside the `{ ... }`, not including the curly braces.
+ pub inner_span: Span,
+ pub inject_use_span: Span,
+}
+
+impl Default for ModSpans {
+ fn default() -> ModSpans {
+ ModSpans { inner_span: Default::default(), inject_use_span: Default::default() }
+ }
+}
+
+/// Foreign module declaration.
+///
+/// E.g., `extern { .. }` or `extern "C" { .. }`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct ForeignMod {
+ /// `unsafe` keyword accepted syntactically for macro DSLs, but not
+ /// semantically by Rust.
+ pub unsafety: Unsafe,
+ pub abi: Option<StrLit>,
+ pub items: Vec<P<ForeignItem>>,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct EnumDef {
+ pub variants: Vec<Variant>,
+}
+/// Enum variant.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Variant {
+ /// Attributes of the variant.
+ pub attrs: AttrVec,
+ /// Id of the variant (not the constructor, see `VariantData::ctor_id()`).
+ pub id: NodeId,
+ /// Span
+ pub span: Span,
+ /// The visibility of the variant. Syntactically accepted but not semantically.
+ pub vis: Visibility,
+ /// Name of the variant.
+ pub ident: Ident,
+
+ /// Fields and constructor id of the variant.
+ pub data: VariantData,
+ /// Explicit discriminant, e.g., `Foo = 1`.
+ pub disr_expr: Option<AnonConst>,
+ /// Is a macro placeholder
+ pub is_placeholder: bool,
+}
+
+/// Part of `use` item to the right of its prefix.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum UseTreeKind {
+ /// `use prefix` or `use prefix as rename`
+ ///
+ /// The extra `NodeId`s are for HIR lowering, when additional statements are created for each
+ /// namespace.
+ Simple(Option<Ident>, NodeId, NodeId),
+ /// `use prefix::{...}`
+ Nested(Vec<(UseTree, NodeId)>),
+ /// `use prefix::*`
+ Glob,
+}
+
+/// A tree of paths sharing common prefixes.
+/// Used in `use` items both at top-level and inside of braces in import groups.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct UseTree {
+ pub prefix: Path,
+ pub kind: UseTreeKind,
+ pub span: Span,
+}
+
+impl UseTree {
+ pub fn ident(&self) -> Ident {
+ match self.kind {
+ UseTreeKind::Simple(Some(rename), ..) => rename,
+ UseTreeKind::Simple(None, ..) => {
+ self.prefix.segments.last().expect("empty prefix in a simple import").ident
+ }
+ _ => panic!("`UseTree::ident` can only be used on a simple import"),
+ }
+ }
+}
+
+/// Distinguishes between `Attribute`s that decorate items and Attributes that
+/// are contained as statements within items. These two cases need to be
+/// distinguished for pretty-printing.
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic)]
+pub enum AttrStyle {
+ Outer,
+ Inner,
+}
+
+rustc_index::newtype_index! {
+ pub struct AttrId {
+ ENCODABLE = custom
+ DEBUG_FORMAT = "AttrId({})"
+ }
+}
+
+impl<S: Encoder> Encodable<S> for AttrId {
+ fn encode(&self, _s: &mut S) {}
+}
+
+impl<D: Decoder> Decodable<D> for AttrId {
+ fn decode(_: &mut D) -> AttrId {
+ crate::attr::mk_attr_id()
+ }
+}
+
+#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+pub struct AttrItem {
+ pub path: Path,
+ pub args: MacArgs,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+/// A list of attributes.
+pub type AttrVec = ThinVec<Attribute>;
+
+/// Metadata associated with an item.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Attribute {
+ pub kind: AttrKind,
+ pub id: AttrId,
+ /// Denotes if the attribute decorates the following construct (outer)
+ /// or the construct this attribute is contained within (inner).
+ pub style: AttrStyle,
+ pub span: Span,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum AttrKind {
+ /// A normal attribute.
+ Normal(AttrItem, Option<LazyTokenStream>),
+
+ /// A doc comment (e.g. `/// ...`, `//! ...`, `/** ... */`, `/*! ... */`).
+ /// Doc attributes (e.g. `#[doc="..."]`) are represented with the `Normal`
+ /// variant (which is much less compact and thus more expensive).
+ DocComment(CommentKind, Symbol),
+}
+
+/// `TraitRef`s appear in impls.
+///
+/// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
+/// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
+/// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
+/// same as the impl's `NodeId`).
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct TraitRef {
+ pub path: Path,
+ pub ref_id: NodeId,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct PolyTraitRef {
+ /// The `'a` in `for<'a> Foo<&'a T>`.
+ pub bound_generic_params: Vec<GenericParam>,
+
+ /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
+ pub trait_ref: TraitRef,
+
+ pub span: Span,
+}
+
+impl PolyTraitRef {
+ pub fn new(generic_params: Vec<GenericParam>, path: Path, span: Span) -> Self {
+ PolyTraitRef {
+ bound_generic_params: generic_params,
+ trait_ref: TraitRef { path, ref_id: DUMMY_NODE_ID },
+ span,
+ }
+ }
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Visibility {
+ pub kind: VisibilityKind,
+ pub span: Span,
+ pub tokens: Option<LazyTokenStream>,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum VisibilityKind {
+ Public,
+ Restricted { path: P<Path>, id: NodeId },
+ Inherited,
+}
+
+impl VisibilityKind {
+ pub fn is_pub(&self) -> bool {
+ matches!(self, VisibilityKind::Public)
+ }
+}
+
+/// Field definition in a struct, variant or union.
+///
+/// E.g., `bar: usize` as in `struct Foo { bar: usize }`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct FieldDef {
+ pub attrs: AttrVec,
+ pub id: NodeId,
+ pub span: Span,
+ pub vis: Visibility,
+ pub ident: Option<Ident>,
+
+ pub ty: P<Ty>,
+ pub is_placeholder: bool,
+}
+
+/// Fields and constructor ids of enum variants and structs.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum VariantData {
+ /// Struct variant.
+ ///
+ /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
+ Struct(Vec<FieldDef>, bool),
+ /// Tuple variant.
+ ///
+ /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
+ Tuple(Vec<FieldDef>, NodeId),
+ /// Unit variant.
+ ///
+ /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
+ Unit(NodeId),
+}
+
+impl VariantData {
+ /// Return the fields of this variant.
+ pub fn fields(&self) -> &[FieldDef] {
+ match *self {
+ VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, _) => fields,
+ _ => &[],
+ }
+ }
+
+ /// Return the `NodeId` of this variant's constructor, if it has one.
+ pub fn ctor_id(&self) -> Option<NodeId> {
+ match *self {
+ VariantData::Struct(..) => None,
+ VariantData::Tuple(_, id) | VariantData::Unit(id) => Some(id),
+ }
+ }
+}
+
+/// An item definition.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Item<K = ItemKind> {
+ pub attrs: Vec<Attribute>,
+ pub id: NodeId,
+ pub span: Span,
+ pub vis: Visibility,
+ /// The name of the item.
+ /// It might be a dummy name in case of anonymous items.
+ pub ident: Ident,
+
+ pub kind: K,
+
+ /// Original tokens this item was parsed from. This isn't necessarily
+ /// available for all items, although over time more and more items should
+ /// have this be `Some`. Right now this is primarily used for procedural
+ /// macros, notably custom attributes.
+ ///
+ /// Note that the tokens here do not include the outer attributes, but will
+ /// include inner attributes.
+ pub tokens: Option<LazyTokenStream>,
+}
+
+impl Item {
+ /// Return the span that encompasses the attributes.
+ pub fn span_with_attributes(&self) -> Span {
+ self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span))
+ }
+}
+
+/// `extern` qualifier on a function item or function type.
+#[derive(Clone, Copy, Encodable, Decodable, Debug)]
+pub enum Extern {
+ None,
+ Implicit(Span),
+ Explicit(StrLit, Span),
+}
+
+impl Extern {
+ pub fn from_abi(abi: Option<StrLit>, span: Span) -> Extern {
+ match abi {
+ Some(name) => Extern::Explicit(name, span),
+ None => Extern::Implicit(span),
+ }
+ }
+}
+
+/// A function header.
+///
+/// All the information between the visibility and the name of the function is
+/// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`).
+#[derive(Clone, Copy, Encodable, Decodable, Debug)]
+pub struct FnHeader {
+ pub unsafety: Unsafe,
+ pub asyncness: Async,
+ pub constness: Const,
+ pub ext: Extern,
+}
+
+impl FnHeader {
+ /// Does this function header have any qualifiers or is it empty?
+ pub fn has_qualifiers(&self) -> bool {
+ let Self { unsafety, asyncness, constness, ext } = self;
+ matches!(unsafety, Unsafe::Yes(_))
+ || asyncness.is_async()
+ || matches!(constness, Const::Yes(_))
+ || !matches!(ext, Extern::None)
+ }
+}
+
+impl Default for FnHeader {
+ fn default() -> FnHeader {
+ FnHeader {
+ unsafety: Unsafe::No,
+ asyncness: Async::No,
+ constness: Const::No,
+ ext: Extern::None,
+ }
+ }
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Trait {
+ pub unsafety: Unsafe,
+ pub is_auto: IsAuto,
+ pub generics: Generics,
+ pub bounds: GenericBounds,
+ pub items: Vec<P<AssocItem>>,
+}
+
+/// The location of a where clause on a `TyAlias` (`Span`) and whether there was
+/// a `where` keyword (`bool`). This is split out from `WhereClause`, since there
+/// are two locations for where clause on type aliases, but their predicates
+/// are concatenated together.
+///
+/// Take this example:
+/// ```ignore (only-for-syntax-highlight)
+/// trait Foo {
+/// type Assoc<'a, 'b> where Self: 'a, Self: 'b;
+/// }
+/// impl Foo for () {
+/// type Assoc<'a, 'b> where Self: 'a = () where Self: 'b;
+/// // ^^^^^^^^^^^^^^ first where clause
+/// // ^^^^^^^^^^^^^^ second where clause
+/// }
+/// ```
+///
+/// If there is no where clause, then this is `false` with `DUMMY_SP`.
+#[derive(Copy, Clone, Encodable, Decodable, Debug, Default)]
+pub struct TyAliasWhereClause(pub bool, pub Span);
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct TyAlias {
+ pub defaultness: Defaultness,
+ pub generics: Generics,
+ /// The span information for the two where clauses (before equals, after equals)
+ pub where_clauses: (TyAliasWhereClause, TyAliasWhereClause),
+ /// The index in `generics.where_clause.predicates` that would split into
+ /// predicates from the where clause before the equals and the predicates
+ /// from the where clause after the equals
+ pub where_predicates_split: usize,
+ pub bounds: GenericBounds,
+ pub ty: Option<P<Ty>>,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Impl {
+ pub defaultness: Defaultness,
+ pub unsafety: Unsafe,
+ pub generics: Generics,
+ pub constness: Const,
+ pub polarity: ImplPolarity,
+ /// The trait being implemented, if any.
+ pub of_trait: Option<TraitRef>,
+ pub self_ty: P<Ty>,
+ pub items: Vec<P<AssocItem>>,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct Fn {
+ pub defaultness: Defaultness,
+ pub generics: Generics,
+ pub sig: FnSig,
+ pub body: Option<P<Block>>,
+}
+
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum ItemKind {
+ /// An `extern crate` item, with the optional *original* crate name if the crate was renamed.
+ ///
+ /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
+ ExternCrate(Option<Symbol>),
+ /// A use declaration item (`use`).
+ ///
+ /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
+ Use(UseTree),
+ /// A static item (`static`).
+ ///
+ /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
+ Static(P<Ty>, Mutability, Option<P<Expr>>),
+ /// A constant item (`const`).
+ ///
+ /// E.g., `const FOO: i32 = 42;`.
+ Const(Defaultness, P<Ty>, Option<P<Expr>>),
+ /// A function declaration (`fn`).
+ ///
+ /// E.g., `fn foo(bar: usize) -> usize { .. }`.
+ Fn(Box<Fn>),
+ /// A module declaration (`mod`).
+ ///
+ /// E.g., `mod foo;` or `mod foo { .. }`.
+ /// `unsafe` keyword on modules is accepted syntactically for macro DSLs, but not
+ /// semantically by Rust.
+ Mod(Unsafe, ModKind),
+ /// An external module (`extern`).
+ ///
+ /// E.g., `extern {}` or `extern "C" {}`.
+ ForeignMod(ForeignMod),
+ /// Module-level inline assembly (from `global_asm!()`).
+ GlobalAsm(Box<InlineAsm>),
+ /// A type alias (`type`).
+ ///
+ /// E.g., `type Foo = Bar<u8>;`.
+ TyAlias(Box<TyAlias>),
+ /// An enum definition (`enum`).
+ ///
+ /// E.g., `enum Foo<A, B> { C<A>, D<B> }`.
+ Enum(EnumDef, Generics),
+ /// A struct definition (`struct`).
+ ///
+ /// E.g., `struct Foo<A> { x: A }`.
+ Struct(VariantData, Generics),
+ /// A union definition (`union`).
+ ///
+ /// E.g., `union Foo<A, B> { x: A, y: B }`.
+ Union(VariantData, Generics),
+ /// A trait declaration (`trait`).
+ ///
+ /// E.g., `trait Foo { .. }`, `trait Foo<T> { .. }` or `auto trait Foo {}`.
+ Trait(Box<Trait>),
+ /// Trait alias
+ ///
+ /// E.g., `trait Foo = Bar + Quux;`.
+ TraitAlias(Generics, GenericBounds),
+ /// An implementation.
+ ///
+ /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
+ Impl(Box<Impl>),
+ /// A macro invocation.
+ ///
+ /// E.g., `foo!(..)`.
+ MacCall(MacCall),
+
+ /// A macro definition.
+ MacroDef(MacroDef),
+}
+
+impl ItemKind {
+ pub fn article(&self) -> &str {
+ use ItemKind::*;
+ match self {
+ Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
+ | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
+ ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
+ }
+ }
+
+ pub fn descr(&self) -> &str {
+ match self {
+ ItemKind::ExternCrate(..) => "extern crate",
+ ItemKind::Use(..) => "`use` import",
+ ItemKind::Static(..) => "static item",
+ ItemKind::Const(..) => "constant item",
+ ItemKind::Fn(..) => "function",
+ ItemKind::Mod(..) => "module",
+ ItemKind::ForeignMod(..) => "extern block",
+ ItemKind::GlobalAsm(..) => "global asm item",
+ ItemKind::TyAlias(..) => "type alias",
+ ItemKind::Enum(..) => "enum",
+ ItemKind::Struct(..) => "struct",
+ ItemKind::Union(..) => "union",
+ ItemKind::Trait(..) => "trait",
+ ItemKind::TraitAlias(..) => "trait alias",
+ ItemKind::MacCall(..) => "item macro invocation",
+ ItemKind::MacroDef(..) => "macro definition",
+ ItemKind::Impl { .. } => "implementation",
+ }
+ }
+
+ pub fn generics(&self) -> Option<&Generics> {
+ match self {
+ Self::Fn(box Fn { generics, .. })
+ | Self::TyAlias(box TyAlias { generics, .. })
+ | Self::Enum(_, generics)
+ | Self::Struct(_, generics)
+ | Self::Union(_, generics)
+ | Self::Trait(box Trait { generics, .. })
+ | Self::TraitAlias(generics, _)
+ | Self::Impl(box Impl { generics, .. }) => Some(generics),
+ _ => None,
+ }
+ }
+}
+
+/// Represents associated items.
+/// These include items in `impl` and `trait` definitions.
+pub type AssocItem = Item<AssocItemKind>;
+
+/// Represents associated item kinds.
+///
+/// The term "provided" in the variants below refers to the item having a default
+/// definition / body. Meanwhile, a "required" item lacks a definition / body.
+/// In an implementation, all items must be provided.
+/// The `Option`s below denote the bodies, where `Some(_)`
+/// means "provided" and conversely `None` means "required".
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum AssocItemKind {
+ /// An associated constant, `const $ident: $ty $def?;` where `def ::= "=" $expr? ;`.
+ /// If `def` is parsed, then the constant is provided, and otherwise required.
+ Const(Defaultness, P<Ty>, Option<P<Expr>>),
+ /// An associated function.
+ Fn(Box<Fn>),
+ /// An associated type.
+ TyAlias(Box<TyAlias>),
+ /// A macro expanding to associated items.
+ MacCall(MacCall),
+}
+
+impl AssocItemKind {
+ pub fn defaultness(&self) -> Defaultness {
+ match *self {
+ Self::Const(defaultness, ..)
+ | Self::Fn(box Fn { defaultness, .. })
+ | Self::TyAlias(box TyAlias { defaultness, .. }) => defaultness,
+ Self::MacCall(..) => Defaultness::Final,
+ }
+ }
+}
+
+impl From<AssocItemKind> for ItemKind {
+ fn from(assoc_item_kind: AssocItemKind) -> ItemKind {
+ match assoc_item_kind {
+ AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
+ AssocItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
+ AssocItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
+ AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
+ }
+ }
+}
+
+impl TryFrom<ItemKind> for AssocItemKind {
+ type Error = ItemKind;
+
+ fn try_from(item_kind: ItemKind) -> Result<AssocItemKind, ItemKind> {
+ Ok(match item_kind {
+ ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
+ ItemKind::Fn(fn_kind) => AssocItemKind::Fn(fn_kind),
+ ItemKind::TyAlias(ty_alias_kind) => AssocItemKind::TyAlias(ty_alias_kind),
+ ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
+ _ => return Err(item_kind),
+ })
+ }
+}
+
+/// An item in `extern` block.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum ForeignItemKind {
+ /// A foreign static item (`static FOO: u8`).
+ Static(P<Ty>, Mutability, Option<P<Expr>>),
+ /// An foreign function.
+ Fn(Box<Fn>),
+ /// An foreign type.
+ TyAlias(Box<TyAlias>),
+ /// A macro expanding to foreign items.
+ MacCall(MacCall),
+}
+
+impl From<ForeignItemKind> for ItemKind {
+ fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
+ match foreign_item_kind {
+ ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
+ ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
+ ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
+ ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
+ }
+ }
+}
+
+impl TryFrom<ItemKind> for ForeignItemKind {
+ type Error = ItemKind;
+
+ fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
+ Ok(match item_kind {
+ ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
+ ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
+ ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
+ ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
+ _ => return Err(item_kind),
+ })
+ }
+}
+
+pub type ForeignItem = Item<ForeignItemKind>;
+
+// Some nodes are used a lot. Make sure they don't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+mod size_asserts {
+ use super::*;
+ // These are in alphabetical order, which is easy to maintain.
+ rustc_data_structures::static_assert_size!(AssocItemKind, 72);
+ rustc_data_structures::static_assert_size!(Attribute, 152);
+ rustc_data_structures::static_assert_size!(Block, 48);
+ rustc_data_structures::static_assert_size!(Expr, 104);
+ rustc_data_structures::static_assert_size!(Fn, 192);
+ rustc_data_structures::static_assert_size!(ForeignItemKind, 72);
+ rustc_data_structures::static_assert_size!(GenericBound, 88);
+ rustc_data_structures::static_assert_size!(Generics, 72);
+ rustc_data_structures::static_assert_size!(Impl, 200);
+ rustc_data_structures::static_assert_size!(Item, 200);
+ rustc_data_structures::static_assert_size!(ItemKind, 112);
+ rustc_data_structures::static_assert_size!(Lit, 48);
+ rustc_data_structures::static_assert_size!(Pat, 120);
+ rustc_data_structures::static_assert_size!(Path, 40);
+ rustc_data_structures::static_assert_size!(PathSegment, 24);
+ rustc_data_structures::static_assert_size!(Stmt, 32);
+ rustc_data_structures::static_assert_size!(Ty, 96);
+}