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-rw-r--r--compiler/rustc_ast/Cargo.toml18
-rw-r--r--compiler/rustc_ast/README.md8
-rw-r--r--compiler/rustc_ast/src/ast.rs3051
-rw-r--r--compiler/rustc_ast/src/ast_traits.rs442
-rw-r--r--compiler/rustc_ast/src/attr/mod.rs634
-rw-r--r--compiler/rustc_ast/src/entry.rs8
-rw-r--r--compiler/rustc_ast/src/expand/allocator.rs53
-rw-r--r--compiler/rustc_ast/src/expand/mod.rs3
-rw-r--r--compiler/rustc_ast/src/lib.rs63
-rw-r--r--compiler/rustc_ast/src/mut_visit.rs1601
-rw-r--r--compiler/rustc_ast/src/node_id.rs40
-rw-r--r--compiler/rustc_ast/src/ptr.rs212
-rw-r--r--compiler/rustc_ast/src/token.rs851
-rw-r--r--compiler/rustc_ast/src/tokenstream.rs681
-rw-r--r--compiler/rustc_ast/src/util/classify.rs52
-rw-r--r--compiler/rustc_ast/src/util/comments.rs255
-rw-r--r--compiler/rustc_ast/src/util/comments/tests.rs61
-rw-r--r--compiler/rustc_ast/src/util/literal.rs336
-rw-r--r--compiler/rustc_ast/src/util/parser.rs406
-rw-r--r--compiler/rustc_ast/src/util/unicode.rs35
-rw-r--r--compiler/rustc_ast/src/visit.rs959
21 files changed, 9769 insertions, 0 deletions
diff --git a/compiler/rustc_ast/Cargo.toml b/compiler/rustc_ast/Cargo.toml
new file mode 100644
index 000000000..9822e9864
--- /dev/null
+++ b/compiler/rustc_ast/Cargo.toml
@@ -0,0 +1,18 @@
+[package]
+name = "rustc_ast"
+version = "0.0.0"
+edition = "2021"
+
+[lib]
+doctest = false
+
+[dependencies]
+rustc_serialize = { path = "../rustc_serialize" }
+tracing = "0.1"
+rustc_span = { path = "../rustc_span" }
+rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_index = { path = "../rustc_index" }
+rustc_lexer = { path = "../rustc_lexer" }
+rustc_macros = { path = "../rustc_macros" }
+smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
+bitflags = "1.2.1"
diff --git a/compiler/rustc_ast/README.md b/compiler/rustc_ast/README.md
new file mode 100644
index 000000000..b2b90fed0
--- /dev/null
+++ b/compiler/rustc_ast/README.md
@@ -0,0 +1,8 @@
+The `rustc_ast` crate contains those things concerned purely with syntax
+– that is, the AST ("abstract syntax tree"), along with some definitions for tokens and token streams, data structures/traits for mutating ASTs, and shared definitions for other AST-related parts of the compiler (like the lexer and macro-expansion).
+
+For more information about how these things work in rustc, see the
+rustc dev guide:
+
+- [Parsing](https://rustc-dev-guide.rust-lang.org/the-parser.html)
+- [Macro Expansion](https://rustc-dev-guide.rust-lang.org/macro-expansion.html)
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
new file mode 100644
index 000000000..870a7c0be
--- /dev/null
+++ b/compiler/rustc_ast/src/ast.rs
@@ -0,0 +1,3051 @@
+//! 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);
+}
diff --git a/compiler/rustc_ast/src/ast_traits.rs b/compiler/rustc_ast/src/ast_traits.rs
new file mode 100644
index 000000000..5c30a75a1
--- /dev/null
+++ b/compiler/rustc_ast/src/ast_traits.rs
@@ -0,0 +1,442 @@
+//! A set of traits implemented for various AST nodes,
+//! typically those used in AST fragments during macro expansion.
+//! The traits are not implemented exhaustively, only when actually necessary.
+
+use crate::ptr::P;
+use crate::token::Nonterminal;
+use crate::tokenstream::LazyTokenStream;
+use crate::{Arm, Crate, ExprField, FieldDef, GenericParam, Param, PatField, Variant};
+use crate::{AssocItem, Expr, ForeignItem, Item, NodeId};
+use crate::{AttrItem, AttrKind, Block, Pat, Path, Ty, Visibility};
+use crate::{AttrVec, Attribute, Stmt, StmtKind};
+
+use rustc_span::Span;
+
+use std::fmt;
+use std::marker::PhantomData;
+
+/// A utility trait to reduce boilerplate.
+/// Standard `Deref(Mut)` cannot be reused due to coherence.
+pub trait AstDeref {
+ type Target;
+ fn ast_deref(&self) -> &Self::Target;
+ fn ast_deref_mut(&mut self) -> &mut Self::Target;
+}
+
+macro_rules! impl_not_ast_deref {
+ ($($T:ty),+ $(,)?) => {
+ $(
+ impl !AstDeref for $T {}
+ )+
+ };
+}
+
+impl_not_ast_deref!(AssocItem, Expr, ForeignItem, Item, Stmt);
+
+impl<T> AstDeref for P<T> {
+ type Target = T;
+ fn ast_deref(&self) -> &Self::Target {
+ self
+ }
+ fn ast_deref_mut(&mut self) -> &mut Self::Target {
+ self
+ }
+}
+
+/// A trait for AST nodes having an ID.
+pub trait HasNodeId {
+ fn node_id(&self) -> NodeId;
+ fn node_id_mut(&mut self) -> &mut NodeId;
+}
+
+macro_rules! impl_has_node_id {
+ ($($T:ty),+ $(,)?) => {
+ $(
+ impl HasNodeId for $T {
+ fn node_id(&self) -> NodeId {
+ self.id
+ }
+ fn node_id_mut(&mut self) -> &mut NodeId {
+ &mut self.id
+ }
+ }
+ )+
+ };
+}
+
+impl_has_node_id!(
+ Arm,
+ AssocItem,
+ Crate,
+ Expr,
+ ExprField,
+ FieldDef,
+ ForeignItem,
+ GenericParam,
+ Item,
+ Param,
+ Pat,
+ PatField,
+ Stmt,
+ Ty,
+ Variant,
+);
+
+impl<T: AstDeref<Target: HasNodeId>> HasNodeId for T {
+ fn node_id(&self) -> NodeId {
+ self.ast_deref().node_id()
+ }
+ fn node_id_mut(&mut self) -> &mut NodeId {
+ self.ast_deref_mut().node_id_mut()
+ }
+}
+
+/// A trait for AST nodes having a span.
+pub trait HasSpan {
+ fn span(&self) -> Span;
+}
+
+macro_rules! impl_has_span {
+ ($($T:ty),+ $(,)?) => {
+ $(
+ impl HasSpan for $T {
+ fn span(&self) -> Span {
+ self.span
+ }
+ }
+ )+
+ };
+}
+
+impl_has_span!(AssocItem, Block, Expr, ForeignItem, Item, Pat, Path, Stmt, Ty, Visibility);
+
+impl<T: AstDeref<Target: HasSpan>> HasSpan for T {
+ fn span(&self) -> Span {
+ self.ast_deref().span()
+ }
+}
+
+impl HasSpan for AttrItem {
+ fn span(&self) -> Span {
+ self.span()
+ }
+}
+
+/// A trait for AST nodes having (or not having) collected tokens.
+pub trait HasTokens {
+ fn tokens(&self) -> Option<&LazyTokenStream>;
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>>;
+}
+
+macro_rules! impl_has_tokens {
+ ($($T:ty),+ $(,)?) => {
+ $(
+ impl HasTokens for $T {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ self.tokens.as_ref()
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ Some(&mut self.tokens)
+ }
+ }
+ )+
+ };
+}
+
+macro_rules! impl_has_tokens_none {
+ ($($T:ty),+ $(,)?) => {
+ $(
+ impl HasTokens for $T {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ None
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ None
+ }
+ }
+ )+
+ };
+}
+
+impl_has_tokens!(AssocItem, AttrItem, Block, Expr, ForeignItem, Item, Pat, Path, Ty, Visibility);
+impl_has_tokens_none!(Arm, ExprField, FieldDef, GenericParam, Param, PatField, Variant);
+
+impl<T: AstDeref<Target: HasTokens>> HasTokens for T {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ self.ast_deref().tokens()
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ self.ast_deref_mut().tokens_mut()
+ }
+}
+
+impl<T: HasTokens> HasTokens for Option<T> {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ self.as_ref().and_then(|inner| inner.tokens())
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ self.as_mut().and_then(|inner| inner.tokens_mut())
+ }
+}
+
+impl HasTokens for StmtKind {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ match self {
+ StmtKind::Local(local) => local.tokens.as_ref(),
+ StmtKind::Item(item) => item.tokens(),
+ StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.tokens(),
+ StmtKind::Empty => return None,
+ StmtKind::MacCall(mac) => mac.tokens.as_ref(),
+ }
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ match self {
+ StmtKind::Local(local) => Some(&mut local.tokens),
+ StmtKind::Item(item) => item.tokens_mut(),
+ StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.tokens_mut(),
+ StmtKind::Empty => return None,
+ StmtKind::MacCall(mac) => Some(&mut mac.tokens),
+ }
+ }
+}
+
+impl HasTokens for Stmt {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ self.kind.tokens()
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ self.kind.tokens_mut()
+ }
+}
+
+impl HasTokens for Attribute {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ match &self.kind {
+ AttrKind::Normal(_, tokens) => tokens.as_ref(),
+ kind @ AttrKind::DocComment(..) => {
+ panic!("Called tokens on doc comment attr {:?}", kind)
+ }
+ }
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ Some(match &mut self.kind {
+ AttrKind::Normal(_, tokens) => tokens,
+ kind @ AttrKind::DocComment(..) => {
+ panic!("Called tokens_mut on doc comment attr {:?}", kind)
+ }
+ })
+ }
+}
+
+impl HasTokens for Nonterminal {
+ fn tokens(&self) -> Option<&LazyTokenStream> {
+ match self {
+ Nonterminal::NtItem(item) => item.tokens(),
+ Nonterminal::NtStmt(stmt) => stmt.tokens(),
+ Nonterminal::NtExpr(expr) | Nonterminal::NtLiteral(expr) => expr.tokens(),
+ Nonterminal::NtPat(pat) => pat.tokens(),
+ Nonterminal::NtTy(ty) => ty.tokens(),
+ Nonterminal::NtMeta(attr_item) => attr_item.tokens(),
+ Nonterminal::NtPath(path) => path.tokens(),
+ Nonterminal::NtVis(vis) => vis.tokens(),
+ Nonterminal::NtBlock(block) => block.tokens(),
+ Nonterminal::NtIdent(..) | Nonterminal::NtLifetime(..) => None,
+ }
+ }
+ fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+ match self {
+ Nonterminal::NtItem(item) => item.tokens_mut(),
+ Nonterminal::NtStmt(stmt) => stmt.tokens_mut(),
+ Nonterminal::NtExpr(expr) | Nonterminal::NtLiteral(expr) => expr.tokens_mut(),
+ Nonterminal::NtPat(pat) => pat.tokens_mut(),
+ Nonterminal::NtTy(ty) => ty.tokens_mut(),
+ Nonterminal::NtMeta(attr_item) => attr_item.tokens_mut(),
+ Nonterminal::NtPath(path) => path.tokens_mut(),
+ Nonterminal::NtVis(vis) => vis.tokens_mut(),
+ Nonterminal::NtBlock(block) => block.tokens_mut(),
+ Nonterminal::NtIdent(..) | Nonterminal::NtLifetime(..) => None,
+ }
+ }
+}
+
+/// A trait for AST nodes having (or not having) attributes.
+pub trait HasAttrs {
+ /// This is `true` if this `HasAttrs` might support 'custom' (proc-macro) inner
+ /// attributes. Attributes like `#![cfg]` and `#![cfg_attr]` are not
+ /// considered 'custom' attributes.
+ ///
+ /// If this is `false`, then this `HasAttrs` definitely does
+ /// not support 'custom' inner attributes, which enables some optimizations
+ /// during token collection.
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool;
+ fn attrs(&self) -> &[Attribute];
+ fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>));
+}
+
+macro_rules! impl_has_attrs {
+ (const SUPPORTS_CUSTOM_INNER_ATTRS: bool = $inner:literal, $($T:ty),+ $(,)?) => {
+ $(
+ impl HasAttrs for $T {
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = $inner;
+
+ fn attrs(&self) -> &[Attribute] {
+ &self.attrs
+ }
+
+ fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
+ VecOrAttrVec::visit(&mut self.attrs, f)
+ }
+ }
+ )+
+ };
+}
+
+macro_rules! impl_has_attrs_none {
+ ($($T:ty),+ $(,)?) => {
+ $(
+ impl HasAttrs for $T {
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = false;
+ fn attrs(&self) -> &[Attribute] {
+ &[]
+ }
+ fn visit_attrs(&mut self, _f: impl FnOnce(&mut Vec<Attribute>)) {}
+ }
+ )+
+ };
+}
+
+impl_has_attrs!(
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = true,
+ AssocItem,
+ ForeignItem,
+ Item,
+);
+impl_has_attrs!(
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = false,
+ Arm,
+ Crate,
+ Expr,
+ ExprField,
+ FieldDef,
+ GenericParam,
+ Param,
+ PatField,
+ Variant,
+);
+impl_has_attrs_none!(Attribute, AttrItem, Block, Pat, Path, Ty, Visibility);
+
+impl<T: AstDeref<Target: HasAttrs>> HasAttrs for T {
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = T::Target::SUPPORTS_CUSTOM_INNER_ATTRS;
+ fn attrs(&self) -> &[Attribute] {
+ self.ast_deref().attrs()
+ }
+ fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
+ self.ast_deref_mut().visit_attrs(f)
+ }
+}
+
+impl<T: HasAttrs> HasAttrs for Option<T> {
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = T::SUPPORTS_CUSTOM_INNER_ATTRS;
+ fn attrs(&self) -> &[Attribute] {
+ self.as_ref().map(|inner| inner.attrs()).unwrap_or(&[])
+ }
+ fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
+ if let Some(inner) = self.as_mut() {
+ inner.visit_attrs(f);
+ }
+ }
+}
+
+impl HasAttrs for StmtKind {
+ // This might be a `StmtKind::Item`, which contains
+ // an item that supports inner attrs.
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = true;
+
+ fn attrs(&self) -> &[Attribute] {
+ match self {
+ StmtKind::Local(local) => &local.attrs,
+ StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.attrs(),
+ StmtKind::Item(item) => item.attrs(),
+ StmtKind::Empty => &[],
+ StmtKind::MacCall(mac) => &mac.attrs,
+ }
+ }
+
+ fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
+ match self {
+ StmtKind::Local(local) => visit_attrvec(&mut local.attrs, f),
+ StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.visit_attrs(f),
+ StmtKind::Item(item) => item.visit_attrs(f),
+ StmtKind::Empty => {}
+ StmtKind::MacCall(mac) => visit_attrvec(&mut mac.attrs, f),
+ }
+ }
+}
+
+impl HasAttrs for Stmt {
+ const SUPPORTS_CUSTOM_INNER_ATTRS: bool = StmtKind::SUPPORTS_CUSTOM_INNER_ATTRS;
+ fn attrs(&self) -> &[Attribute] {
+ self.kind.attrs()
+ }
+ fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
+ self.kind.visit_attrs(f);
+ }
+}
+
+/// Helper trait for the impls above. Abstracts over
+/// the two types of attribute fields that AST nodes
+/// may have (`Vec<Attribute>` or `AttrVec`).
+trait VecOrAttrVec {
+ fn visit(&mut self, f: impl FnOnce(&mut Vec<Attribute>));
+}
+
+impl VecOrAttrVec for Vec<Attribute> {
+ fn visit(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
+ f(self)
+ }
+}
+
+impl VecOrAttrVec for AttrVec {
+ fn visit(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
+ visit_attrvec(self, f)
+ }
+}
+
+fn visit_attrvec(attrs: &mut AttrVec, f: impl FnOnce(&mut Vec<Attribute>)) {
+ crate::mut_visit::visit_clobber(attrs, |attrs| {
+ let mut vec = attrs.into();
+ f(&mut vec);
+ vec.into()
+ });
+}
+
+/// A newtype around an AST node that implements the traits above if the node implements them.
+pub struct AstNodeWrapper<Wrapped, Tag> {
+ pub wrapped: Wrapped,
+ pub tag: PhantomData<Tag>,
+}
+
+impl<Wrapped, Tag> AstNodeWrapper<Wrapped, Tag> {
+ pub fn new(wrapped: Wrapped, _tag: Tag) -> AstNodeWrapper<Wrapped, Tag> {
+ AstNodeWrapper { wrapped, tag: Default::default() }
+ }
+}
+
+impl<Wrapped, Tag> AstDeref for AstNodeWrapper<Wrapped, Tag> {
+ type Target = Wrapped;
+ fn ast_deref(&self) -> &Self::Target {
+ &self.wrapped
+ }
+ fn ast_deref_mut(&mut self) -> &mut Self::Target {
+ &mut self.wrapped
+ }
+}
+
+impl<Wrapped: fmt::Debug, Tag> fmt::Debug for AstNodeWrapper<Wrapped, Tag> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_struct("AstNodeWrapper")
+ .field("wrapped", &self.wrapped)
+ .field("tag", &self.tag)
+ .finish()
+ }
+}
diff --git a/compiler/rustc_ast/src/attr/mod.rs b/compiler/rustc_ast/src/attr/mod.rs
new file mode 100644
index 000000000..86af7769d
--- /dev/null
+++ b/compiler/rustc_ast/src/attr/mod.rs
@@ -0,0 +1,634 @@
+//! Functions dealing with attributes and meta items.
+
+use crate::ast;
+use crate::ast::{AttrId, AttrItem, AttrKind, AttrStyle, Attribute};
+use crate::ast::{Lit, LitKind};
+use crate::ast::{MacArgs, MacArgsEq, MacDelimiter, MetaItem, MetaItemKind, NestedMetaItem};
+use crate::ast::{Path, PathSegment};
+use crate::ptr::P;
+use crate::token::{self, CommentKind, Delimiter, Token};
+use crate::tokenstream::{AttrAnnotatedTokenStream, AttrAnnotatedTokenTree};
+use crate::tokenstream::{DelimSpan, Spacing, TokenTree};
+use crate::tokenstream::{LazyTokenStream, TokenStream};
+use crate::util::comments;
+
+use rustc_data_structures::thin_vec::ThinVec;
+use rustc_index::bit_set::GrowableBitSet;
+use rustc_span::source_map::BytePos;
+use rustc_span::symbol::{sym, Ident, Symbol};
+use rustc_span::Span;
+
+use std::iter;
+
+pub struct MarkedAttrs(GrowableBitSet<AttrId>);
+
+impl MarkedAttrs {
+ // We have no idea how many attributes there will be, so just
+ // initiate the vectors with 0 bits. We'll grow them as necessary.
+ pub fn new() -> Self {
+ MarkedAttrs(GrowableBitSet::new_empty())
+ }
+
+ pub fn mark(&mut self, attr: &Attribute) {
+ self.0.insert(attr.id);
+ }
+
+ pub fn is_marked(&self, attr: &Attribute) -> bool {
+ self.0.contains(attr.id)
+ }
+}
+
+impl NestedMetaItem {
+ /// Returns the `MetaItem` if `self` is a `NestedMetaItem::MetaItem`.
+ pub fn meta_item(&self) -> Option<&MetaItem> {
+ match *self {
+ NestedMetaItem::MetaItem(ref item) => Some(item),
+ _ => None,
+ }
+ }
+
+ /// Returns the `Lit` if `self` is a `NestedMetaItem::Literal`s.
+ pub fn literal(&self) -> Option<&Lit> {
+ match *self {
+ NestedMetaItem::Literal(ref lit) => Some(lit),
+ _ => None,
+ }
+ }
+
+ /// Returns `true` if this list item is a MetaItem with a name of `name`.
+ pub fn has_name(&self, name: Symbol) -> bool {
+ self.meta_item().map_or(false, |meta_item| meta_item.has_name(name))
+ }
+
+ /// For a single-segment meta item, returns its name; otherwise, returns `None`.
+ pub fn ident(&self) -> Option<Ident> {
+ self.meta_item().and_then(|meta_item| meta_item.ident())
+ }
+ pub fn name_or_empty(&self) -> Symbol {
+ self.ident().unwrap_or_else(Ident::empty).name
+ }
+
+ /// Gets the string value if `self` is a `MetaItem` and the `MetaItem` is a
+ /// `MetaItemKind::NameValue` variant containing a string, otherwise `None`.
+ pub fn value_str(&self) -> Option<Symbol> {
+ self.meta_item().and_then(|meta_item| meta_item.value_str())
+ }
+
+ /// Returns a name and single literal value tuple of the `MetaItem`.
+ pub fn name_value_literal(&self) -> Option<(Symbol, &Lit)> {
+ self.meta_item().and_then(|meta_item| {
+ meta_item.meta_item_list().and_then(|meta_item_list| {
+ if meta_item_list.len() == 1
+ && let Some(ident) = meta_item.ident()
+ && let Some(lit) = meta_item_list[0].literal()
+ {
+ return Some((ident.name, lit));
+ }
+ None
+ })
+ })
+ }
+
+ /// Gets a list of inner meta items from a list `MetaItem` type.
+ pub fn meta_item_list(&self) -> Option<&[NestedMetaItem]> {
+ self.meta_item().and_then(|meta_item| meta_item.meta_item_list())
+ }
+
+ /// Returns `true` if the variant is `MetaItem`.
+ pub fn is_meta_item(&self) -> bool {
+ self.meta_item().is_some()
+ }
+
+ /// Returns `true` if `self` is a `MetaItem` and the meta item is a word.
+ pub fn is_word(&self) -> bool {
+ self.meta_item().map_or(false, |meta_item| meta_item.is_word())
+ }
+
+ /// See [`MetaItem::name_value_literal_span`].
+ pub fn name_value_literal_span(&self) -> Option<Span> {
+ self.meta_item()?.name_value_literal_span()
+ }
+}
+
+impl Attribute {
+ #[inline]
+ pub fn has_name(&self, name: Symbol) -> bool {
+ match self.kind {
+ AttrKind::Normal(ref item, _) => item.path == name,
+ AttrKind::DocComment(..) => false,
+ }
+ }
+
+ /// For a single-segment attribute, returns its name; otherwise, returns `None`.
+ pub fn ident(&self) -> Option<Ident> {
+ match self.kind {
+ AttrKind::Normal(ref item, _) => {
+ if item.path.segments.len() == 1 {
+ Some(item.path.segments[0].ident)
+ } else {
+ None
+ }
+ }
+ AttrKind::DocComment(..) => None,
+ }
+ }
+ pub fn name_or_empty(&self) -> Symbol {
+ self.ident().unwrap_or_else(Ident::empty).name
+ }
+
+ pub fn value_str(&self) -> Option<Symbol> {
+ match self.kind {
+ AttrKind::Normal(ref item, _) => item.meta_kind().and_then(|kind| kind.value_str()),
+ AttrKind::DocComment(..) => None,
+ }
+ }
+
+ pub fn meta_item_list(&self) -> Option<Vec<NestedMetaItem>> {
+ match self.kind {
+ AttrKind::Normal(ref item, _) => match item.meta_kind() {
+ Some(MetaItemKind::List(list)) => Some(list),
+ _ => None,
+ },
+ AttrKind::DocComment(..) => None,
+ }
+ }
+
+ pub fn is_word(&self) -> bool {
+ if let AttrKind::Normal(item, _) = &self.kind {
+ matches!(item.args, MacArgs::Empty)
+ } else {
+ false
+ }
+ }
+}
+
+impl MetaItem {
+ /// For a single-segment meta item, returns its name; otherwise, returns `None`.
+ pub fn ident(&self) -> Option<Ident> {
+ if self.path.segments.len() == 1 { Some(self.path.segments[0].ident) } else { None }
+ }
+ pub fn name_or_empty(&self) -> Symbol {
+ self.ident().unwrap_or_else(Ident::empty).name
+ }
+
+ // Example:
+ // #[attribute(name = "value")]
+ // ^^^^^^^^^^^^^^
+ pub fn name_value_literal(&self) -> Option<&Lit> {
+ match &self.kind {
+ MetaItemKind::NameValue(v) => Some(v),
+ _ => None,
+ }
+ }
+
+ pub fn value_str(&self) -> Option<Symbol> {
+ match self.kind {
+ MetaItemKind::NameValue(ref v) => match v.kind {
+ LitKind::Str(ref s, _) => Some(*s),
+ _ => None,
+ },
+ _ => None,
+ }
+ }
+
+ pub fn meta_item_list(&self) -> Option<&[NestedMetaItem]> {
+ match self.kind {
+ MetaItemKind::List(ref l) => Some(&l[..]),
+ _ => None,
+ }
+ }
+
+ pub fn is_word(&self) -> bool {
+ matches!(self.kind, MetaItemKind::Word)
+ }
+
+ pub fn has_name(&self, name: Symbol) -> bool {
+ self.path == name
+ }
+
+ /// This is used in case you want the value span instead of the whole attribute. Example:
+ ///
+ /// ```text
+ /// #[doc(alias = "foo")]
+ /// ```
+ ///
+ /// In here, it'll return a span for `"foo"`.
+ pub fn name_value_literal_span(&self) -> Option<Span> {
+ Some(self.name_value_literal()?.span)
+ }
+}
+
+impl AttrItem {
+ pub fn span(&self) -> Span {
+ self.args.span().map_or(self.path.span, |args_span| self.path.span.to(args_span))
+ }
+
+ pub fn meta(&self, span: Span) -> Option<MetaItem> {
+ Some(MetaItem {
+ path: self.path.clone(),
+ kind: MetaItemKind::from_mac_args(&self.args)?,
+ span,
+ })
+ }
+
+ pub fn meta_kind(&self) -> Option<MetaItemKind> {
+ MetaItemKind::from_mac_args(&self.args)
+ }
+}
+
+impl Attribute {
+ pub fn is_doc_comment(&self) -> bool {
+ match self.kind {
+ AttrKind::Normal(..) => false,
+ AttrKind::DocComment(..) => true,
+ }
+ }
+
+ pub fn doc_str_and_comment_kind(&self) -> Option<(Symbol, CommentKind)> {
+ match self.kind {
+ AttrKind::DocComment(kind, data) => Some((data, kind)),
+ AttrKind::Normal(ref item, _) if item.path == sym::doc => item
+ .meta_kind()
+ .and_then(|kind| kind.value_str())
+ .map(|data| (data, CommentKind::Line)),
+ _ => None,
+ }
+ }
+
+ pub fn doc_str(&self) -> Option<Symbol> {
+ match self.kind {
+ AttrKind::DocComment(.., data) => Some(data),
+ AttrKind::Normal(ref item, _) if item.path == sym::doc => {
+ item.meta_kind().and_then(|kind| kind.value_str())
+ }
+ _ => None,
+ }
+ }
+
+ pub fn may_have_doc_links(&self) -> bool {
+ self.doc_str().map_or(false, |s| comments::may_have_doc_links(s.as_str()))
+ }
+
+ pub fn get_normal_item(&self) -> &AttrItem {
+ match self.kind {
+ AttrKind::Normal(ref item, _) => item,
+ AttrKind::DocComment(..) => panic!("unexpected doc comment"),
+ }
+ }
+
+ pub fn unwrap_normal_item(self) -> AttrItem {
+ match self.kind {
+ AttrKind::Normal(item, _) => item,
+ AttrKind::DocComment(..) => panic!("unexpected doc comment"),
+ }
+ }
+
+ /// Extracts the MetaItem from inside this Attribute.
+ pub fn meta(&self) -> Option<MetaItem> {
+ match self.kind {
+ AttrKind::Normal(ref item, _) => item.meta(self.span),
+ AttrKind::DocComment(..) => None,
+ }
+ }
+
+ pub fn meta_kind(&self) -> Option<MetaItemKind> {
+ match self.kind {
+ AttrKind::Normal(ref item, _) => item.meta_kind(),
+ AttrKind::DocComment(..) => None,
+ }
+ }
+
+ pub fn tokens(&self) -> AttrAnnotatedTokenStream {
+ match self.kind {
+ AttrKind::Normal(_, ref tokens) => tokens
+ .as_ref()
+ .unwrap_or_else(|| panic!("attribute is missing tokens: {:?}", self))
+ .create_token_stream(),
+ AttrKind::DocComment(comment_kind, data) => AttrAnnotatedTokenStream::from((
+ AttrAnnotatedTokenTree::Token(Token::new(
+ token::DocComment(comment_kind, self.style, data),
+ self.span,
+ )),
+ Spacing::Alone,
+ )),
+ }
+ }
+}
+
+/* Constructors */
+
+pub fn mk_name_value_item_str(ident: Ident, str: Symbol, str_span: Span) -> MetaItem {
+ let lit_kind = LitKind::Str(str, ast::StrStyle::Cooked);
+ mk_name_value_item(ident, lit_kind, str_span)
+}
+
+pub fn mk_name_value_item(ident: Ident, lit_kind: LitKind, lit_span: Span) -> MetaItem {
+ let lit = Lit::from_lit_kind(lit_kind, lit_span);
+ let span = ident.span.to(lit_span);
+ MetaItem { path: Path::from_ident(ident), span, kind: MetaItemKind::NameValue(lit) }
+}
+
+pub fn mk_list_item(ident: Ident, items: Vec<NestedMetaItem>) -> MetaItem {
+ MetaItem { path: Path::from_ident(ident), span: ident.span, kind: MetaItemKind::List(items) }
+}
+
+pub fn mk_word_item(ident: Ident) -> MetaItem {
+ MetaItem { path: Path::from_ident(ident), span: ident.span, kind: MetaItemKind::Word }
+}
+
+pub fn mk_nested_word_item(ident: Ident) -> NestedMetaItem {
+ NestedMetaItem::MetaItem(mk_word_item(ident))
+}
+
+pub(crate) fn mk_attr_id() -> AttrId {
+ use std::sync::atomic::AtomicU32;
+ use std::sync::atomic::Ordering;
+
+ static NEXT_ATTR_ID: AtomicU32 = AtomicU32::new(0);
+
+ let id = NEXT_ATTR_ID.fetch_add(1, Ordering::SeqCst);
+ assert!(id != u32::MAX);
+ AttrId::from_u32(id)
+}
+
+pub fn mk_attr(style: AttrStyle, path: Path, args: MacArgs, span: Span) -> Attribute {
+ mk_attr_from_item(AttrItem { path, args, tokens: None }, None, style, span)
+}
+
+pub fn mk_attr_from_item(
+ item: AttrItem,
+ tokens: Option<LazyTokenStream>,
+ style: AttrStyle,
+ span: Span,
+) -> Attribute {
+ Attribute { kind: AttrKind::Normal(item, tokens), id: mk_attr_id(), style, span }
+}
+
+/// Returns an inner attribute with the given value and span.
+pub fn mk_attr_inner(item: MetaItem) -> Attribute {
+ mk_attr(AttrStyle::Inner, item.path, item.kind.mac_args(item.span), item.span)
+}
+
+/// Returns an outer attribute with the given value and span.
+pub fn mk_attr_outer(item: MetaItem) -> Attribute {
+ mk_attr(AttrStyle::Outer, item.path, item.kind.mac_args(item.span), item.span)
+}
+
+pub fn mk_doc_comment(
+ comment_kind: CommentKind,
+ style: AttrStyle,
+ data: Symbol,
+ span: Span,
+) -> Attribute {
+ Attribute { kind: AttrKind::DocComment(comment_kind, data), id: mk_attr_id(), style, span }
+}
+
+pub fn list_contains_name(items: &[NestedMetaItem], name: Symbol) -> bool {
+ items.iter().any(|item| item.has_name(name))
+}
+
+impl MetaItem {
+ fn token_trees(&self) -> Vec<TokenTree> {
+ let mut idents = vec![];
+ let mut last_pos = BytePos(0_u32);
+ for (i, segment) in self.path.segments.iter().enumerate() {
+ let is_first = i == 0;
+ if !is_first {
+ let mod_sep_span =
+ Span::new(last_pos, segment.ident.span.lo(), segment.ident.span.ctxt(), None);
+ idents.push(TokenTree::token_alone(token::ModSep, mod_sep_span));
+ }
+ idents.push(TokenTree::Token(Token::from_ast_ident(segment.ident), Spacing::Alone));
+ last_pos = segment.ident.span.hi();
+ }
+ idents.extend(self.kind.token_trees(self.span));
+ idents
+ }
+
+ fn from_tokens<I>(tokens: &mut iter::Peekable<I>) -> Option<MetaItem>
+ where
+ I: Iterator<Item = TokenTree>,
+ {
+ // FIXME: Share code with `parse_path`.
+ let path = match tokens.next().map(TokenTree::uninterpolate) {
+ Some(TokenTree::Token(
+ Token { kind: kind @ (token::Ident(..) | token::ModSep), span },
+ _,
+ )) => 'arm: {
+ let mut segments = if let token::Ident(name, _) = kind {
+ if let Some(TokenTree::Token(Token { kind: token::ModSep, .. }, _)) =
+ tokens.peek()
+ {
+ tokens.next();
+ vec![PathSegment::from_ident(Ident::new(name, span))]
+ } else {
+ break 'arm Path::from_ident(Ident::new(name, span));
+ }
+ } else {
+ vec![PathSegment::path_root(span)]
+ };
+ loop {
+ if let Some(TokenTree::Token(Token { kind: token::Ident(name, _), span }, _)) =
+ tokens.next().map(TokenTree::uninterpolate)
+ {
+ segments.push(PathSegment::from_ident(Ident::new(name, span)));
+ } else {
+ return None;
+ }
+ if let Some(TokenTree::Token(Token { kind: token::ModSep, .. }, _)) =
+ tokens.peek()
+ {
+ tokens.next();
+ } else {
+ break;
+ }
+ }
+ let span = span.with_hi(segments.last().unwrap().ident.span.hi());
+ Path { span, segments, tokens: None }
+ }
+ Some(TokenTree::Token(Token { kind: token::Interpolated(nt), .. }, _)) => match *nt {
+ token::Nonterminal::NtMeta(ref item) => return item.meta(item.path.span),
+ token::Nonterminal::NtPath(ref path) => (**path).clone(),
+ _ => return None,
+ },
+ _ => return None,
+ };
+ let list_closing_paren_pos = tokens.peek().map(|tt| tt.span().hi());
+ let kind = MetaItemKind::from_tokens(tokens)?;
+ let hi = match kind {
+ MetaItemKind::NameValue(ref lit) => lit.span.hi(),
+ MetaItemKind::List(..) => list_closing_paren_pos.unwrap_or(path.span.hi()),
+ _ => path.span.hi(),
+ };
+ let span = path.span.with_hi(hi);
+ Some(MetaItem { path, kind, span })
+ }
+}
+
+impl MetaItemKind {
+ pub fn value_str(&self) -> Option<Symbol> {
+ match self {
+ MetaItemKind::NameValue(ref v) => match v.kind {
+ LitKind::Str(ref s, _) => Some(*s),
+ _ => None,
+ },
+ _ => None,
+ }
+ }
+
+ pub fn mac_args(&self, span: Span) -> MacArgs {
+ match self {
+ MetaItemKind::Word => MacArgs::Empty,
+ MetaItemKind::NameValue(lit) => {
+ let expr = P(ast::Expr {
+ id: ast::DUMMY_NODE_ID,
+ kind: ast::ExprKind::Lit(lit.clone()),
+ span: lit.span,
+ attrs: ThinVec::new(),
+ tokens: None,
+ });
+ MacArgs::Eq(span, MacArgsEq::Ast(expr))
+ }
+ MetaItemKind::List(list) => {
+ let mut tts = Vec::new();
+ for (i, item) in list.iter().enumerate() {
+ if i > 0 {
+ tts.push(TokenTree::token_alone(token::Comma, span));
+ }
+ tts.extend(item.token_trees())
+ }
+ MacArgs::Delimited(
+ DelimSpan::from_single(span),
+ MacDelimiter::Parenthesis,
+ TokenStream::new(tts),
+ )
+ }
+ }
+ }
+
+ fn token_trees(&self, span: Span) -> Vec<TokenTree> {
+ match *self {
+ MetaItemKind::Word => vec![],
+ MetaItemKind::NameValue(ref lit) => {
+ vec![
+ TokenTree::token_alone(token::Eq, span),
+ TokenTree::Token(lit.to_token(), Spacing::Alone),
+ ]
+ }
+ MetaItemKind::List(ref list) => {
+ let mut tokens = Vec::new();
+ for (i, item) in list.iter().enumerate() {
+ if i > 0 {
+ tokens.push(TokenTree::token_alone(token::Comma, span));
+ }
+ tokens.extend(item.token_trees())
+ }
+ vec![TokenTree::Delimited(
+ DelimSpan::from_single(span),
+ Delimiter::Parenthesis,
+ TokenStream::new(tokens),
+ )]
+ }
+ }
+ }
+
+ fn list_from_tokens(tokens: TokenStream) -> Option<MetaItemKind> {
+ let mut tokens = tokens.into_trees().peekable();
+ let mut result = Vec::new();
+ while tokens.peek().is_some() {
+ let item = NestedMetaItem::from_tokens(&mut tokens)?;
+ result.push(item);
+ match tokens.next() {
+ None | Some(TokenTree::Token(Token { kind: token::Comma, .. }, _)) => {}
+ _ => return None,
+ }
+ }
+ Some(MetaItemKind::List(result))
+ }
+
+ fn name_value_from_tokens(
+ tokens: &mut impl Iterator<Item = TokenTree>,
+ ) -> Option<MetaItemKind> {
+ match tokens.next() {
+ Some(TokenTree::Delimited(_, Delimiter::Invisible, inner_tokens)) => {
+ MetaItemKind::name_value_from_tokens(&mut inner_tokens.into_trees())
+ }
+ Some(TokenTree::Token(token, _)) => {
+ Lit::from_token(&token).ok().map(MetaItemKind::NameValue)
+ }
+ _ => None,
+ }
+ }
+
+ fn from_mac_args(args: &MacArgs) -> Option<MetaItemKind> {
+ match args {
+ MacArgs::Empty => Some(MetaItemKind::Word),
+ MacArgs::Delimited(_, MacDelimiter::Parenthesis, tokens) => {
+ MetaItemKind::list_from_tokens(tokens.clone())
+ }
+ MacArgs::Delimited(..) => None,
+ MacArgs::Eq(_, MacArgsEq::Ast(expr)) => match &expr.kind {
+ ast::ExprKind::Lit(lit) => Some(MetaItemKind::NameValue(lit.clone())),
+ _ => None,
+ },
+ MacArgs::Eq(_, MacArgsEq::Hir(lit)) => Some(MetaItemKind::NameValue(lit.clone())),
+ }
+ }
+
+ fn from_tokens(
+ tokens: &mut iter::Peekable<impl Iterator<Item = TokenTree>>,
+ ) -> Option<MetaItemKind> {
+ match tokens.peek() {
+ Some(TokenTree::Delimited(_, Delimiter::Parenthesis, inner_tokens)) => {
+ let inner_tokens = inner_tokens.clone();
+ tokens.next();
+ MetaItemKind::list_from_tokens(inner_tokens)
+ }
+ Some(TokenTree::Delimited(..)) => None,
+ Some(TokenTree::Token(Token { kind: token::Eq, .. }, _)) => {
+ tokens.next();
+ MetaItemKind::name_value_from_tokens(tokens)
+ }
+ _ => Some(MetaItemKind::Word),
+ }
+ }
+}
+
+impl NestedMetaItem {
+ pub fn span(&self) -> Span {
+ match *self {
+ NestedMetaItem::MetaItem(ref item) => item.span,
+ NestedMetaItem::Literal(ref lit) => lit.span,
+ }
+ }
+
+ fn token_trees(&self) -> Vec<TokenTree> {
+ match *self {
+ NestedMetaItem::MetaItem(ref item) => item.token_trees(),
+ NestedMetaItem::Literal(ref lit) => {
+ vec![TokenTree::Token(lit.to_token(), Spacing::Alone)]
+ }
+ }
+ }
+
+ fn from_tokens<I>(tokens: &mut iter::Peekable<I>) -> Option<NestedMetaItem>
+ where
+ I: Iterator<Item = TokenTree>,
+ {
+ match tokens.peek() {
+ Some(TokenTree::Token(token, _))
+ if let Ok(lit) = Lit::from_token(token) =>
+ {
+ tokens.next();
+ return Some(NestedMetaItem::Literal(lit));
+ }
+ Some(TokenTree::Delimited(_, Delimiter::Invisible, inner_tokens)) => {
+ let inner_tokens = inner_tokens.clone();
+ tokens.next();
+ return NestedMetaItem::from_tokens(&mut inner_tokens.into_trees().peekable());
+ }
+ _ => {}
+ }
+ MetaItem::from_tokens(tokens).map(NestedMetaItem::MetaItem)
+ }
+}
diff --git a/compiler/rustc_ast/src/entry.rs b/compiler/rustc_ast/src/entry.rs
new file mode 100644
index 000000000..337014619
--- /dev/null
+++ b/compiler/rustc_ast/src/entry.rs
@@ -0,0 +1,8 @@
+#[derive(Debug)]
+pub enum EntryPointType {
+ None,
+ MainNamed,
+ RustcMainAttr,
+ Start,
+ OtherMain, // Not an entry point, but some other function named main
+}
diff --git a/compiler/rustc_ast/src/expand/allocator.rs b/compiler/rustc_ast/src/expand/allocator.rs
new file mode 100644
index 000000000..1976e4ad3
--- /dev/null
+++ b/compiler/rustc_ast/src/expand/allocator.rs
@@ -0,0 +1,53 @@
+use rustc_span::symbol::{sym, Symbol};
+
+#[derive(Clone, Debug, Copy, HashStable_Generic)]
+pub enum AllocatorKind {
+ Global,
+ Default,
+}
+
+impl AllocatorKind {
+ pub fn fn_name(&self, base: Symbol) -> String {
+ match *self {
+ AllocatorKind::Global => format!("__rg_{}", base),
+ AllocatorKind::Default => format!("__rdl_{}", base),
+ }
+ }
+}
+
+pub enum AllocatorTy {
+ Layout,
+ Ptr,
+ ResultPtr,
+ Unit,
+ Usize,
+}
+
+pub struct AllocatorMethod {
+ pub name: Symbol,
+ pub inputs: &'static [AllocatorTy],
+ pub output: AllocatorTy,
+}
+
+pub static ALLOCATOR_METHODS: &[AllocatorMethod] = &[
+ AllocatorMethod {
+ name: sym::alloc,
+ inputs: &[AllocatorTy::Layout],
+ output: AllocatorTy::ResultPtr,
+ },
+ AllocatorMethod {
+ name: sym::dealloc,
+ inputs: &[AllocatorTy::Ptr, AllocatorTy::Layout],
+ output: AllocatorTy::Unit,
+ },
+ AllocatorMethod {
+ name: sym::realloc,
+ inputs: &[AllocatorTy::Ptr, AllocatorTy::Layout, AllocatorTy::Usize],
+ output: AllocatorTy::ResultPtr,
+ },
+ AllocatorMethod {
+ name: sym::alloc_zeroed,
+ inputs: &[AllocatorTy::Layout],
+ output: AllocatorTy::ResultPtr,
+ },
+];
diff --git a/compiler/rustc_ast/src/expand/mod.rs b/compiler/rustc_ast/src/expand/mod.rs
new file mode 100644
index 000000000..2ee1bfe0a
--- /dev/null
+++ b/compiler/rustc_ast/src/expand/mod.rs
@@ -0,0 +1,3 @@
+//! Definitions shared by macros / syntax extensions and e.g. `rustc_middle`.
+
+pub mod allocator;
diff --git a/compiler/rustc_ast/src/lib.rs b/compiler/rustc_ast/src/lib.rs
new file mode 100644
index 000000000..4b94ec0d6
--- /dev/null
+++ b/compiler/rustc_ast/src/lib.rs
@@ -0,0 +1,63 @@
+//! The Rust Abstract Syntax Tree (AST).
+//!
+//! # Note
+//!
+//! This API is completely unstable and subject to change.
+
+#![doc(
+ html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
+ test(attr(deny(warnings)))
+)]
+#![feature(associated_type_bounds)]
+#![feature(box_patterns)]
+#![feature(const_default_impls)]
+#![feature(const_trait_impl)]
+#![feature(if_let_guard)]
+#![feature(label_break_value)]
+#![feature(let_chains)]
+#![feature(min_specialization)]
+#![feature(negative_impls)]
+#![feature(slice_internals)]
+#![feature(stmt_expr_attributes)]
+#![recursion_limit = "256"]
+
+#[macro_use]
+extern crate rustc_macros;
+
+pub mod util {
+ pub mod classify;
+ pub mod comments;
+ pub mod literal;
+ pub mod parser;
+ pub mod unicode;
+}
+
+pub mod ast;
+pub mod ast_traits;
+pub mod attr;
+pub mod entry;
+pub mod expand;
+pub mod mut_visit;
+pub mod node_id;
+pub mod ptr;
+pub mod token;
+pub mod tokenstream;
+pub mod visit;
+
+pub use self::ast::*;
+pub use self::ast_traits::{AstDeref, AstNodeWrapper, HasAttrs, HasNodeId, HasSpan, HasTokens};
+
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+
+/// Requirements for a `StableHashingContext` to be used in this crate.
+/// This is a hack to allow using the `HashStable_Generic` derive macro
+/// instead of implementing everything in `rustc_middle`.
+pub trait HashStableContext: rustc_span::HashStableContext {
+ fn hash_attr(&mut self, _: &ast::Attribute, hasher: &mut StableHasher);
+}
+
+impl<AstCtx: crate::HashStableContext> HashStable<AstCtx> for ast::Attribute {
+ fn hash_stable(&self, hcx: &mut AstCtx, hasher: &mut StableHasher) {
+ hcx.hash_attr(self, hasher)
+ }
+}
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
new file mode 100644
index 000000000..01bd498b3
--- /dev/null
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -0,0 +1,1601 @@
+//! A `MutVisitor` represents an AST modification; it accepts an AST piece and
+//! mutates it in place. So, for instance, macro expansion is a `MutVisitor`
+//! that walks over an AST and modifies it.
+//!
+//! Note: using a `MutVisitor` (other than the `MacroExpander` `MutVisitor`) on
+//! an AST before macro expansion is probably a bad idea. For instance,
+//! a `MutVisitor` renaming item names in a module will miss all of those
+//! that are created by the expansion of a macro.
+
+use crate::ast::*;
+use crate::ptr::P;
+use crate::token::{self, Token};
+use crate::tokenstream::*;
+
+use rustc_data_structures::map_in_place::MapInPlace;
+use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::thin_vec::ThinVec;
+use rustc_span::source_map::Spanned;
+use rustc_span::symbol::Ident;
+use rustc_span::Span;
+
+use smallvec::{smallvec, Array, SmallVec};
+use std::ops::DerefMut;
+use std::{panic, ptr};
+
+pub trait ExpectOne<A: Array> {
+ fn expect_one(self, err: &'static str) -> A::Item;
+}
+
+impl<A: Array> ExpectOne<A> for SmallVec<A> {
+ fn expect_one(self, err: &'static str) -> A::Item {
+ assert!(self.len() == 1, "{}", err);
+ self.into_iter().next().unwrap()
+ }
+}
+
+pub trait MutVisitor: Sized {
+ /// Mutable token visiting only exists for the `macro_rules` token marker and should not be
+ /// used otherwise. Token visitor would be entirely separate from the regular visitor if
+ /// the marker didn't have to visit AST fragments in nonterminal tokens.
+ const VISIT_TOKENS: bool = false;
+
+ // Methods in this trait have one of three forms:
+ //
+ // fn visit_t(&mut self, t: &mut T); // common
+ // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
+ // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
+ //
+ // Any additions to this trait should happen in form of a call to a public
+ // `noop_*` function that only calls out to the visitor again, not other
+ // `noop_*` functions. This is a necessary API workaround to the problem of
+ // not being able to call out to the super default method in an overridden
+ // default method.
+ //
+ // When writing these methods, it is better to use destructuring like this:
+ //
+ // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
+ // visit_a(a);
+ // visit_b(b);
+ // }
+ //
+ // than to use field access like this:
+ //
+ // fn visit_abc(&mut self, abc: &mut ABC) {
+ // visit_a(&mut abc.a);
+ // visit_b(&mut abc.b);
+ // // ignore abc.c
+ // }
+ //
+ // As well as being more concise, the former is explicit about which fields
+ // are skipped. Furthermore, if a new field is added, the destructuring
+ // version will cause a compile error, which is good. In comparison, the
+ // field access version will continue working and it would be easy to
+ // forget to add handling for it.
+
+ fn visit_crate(&mut self, c: &mut Crate) {
+ noop_visit_crate(c, self)
+ }
+
+ fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
+ noop_visit_meta_list_item(list_item, self);
+ }
+
+ fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
+ noop_visit_meta_item(meta_item, self);
+ }
+
+ fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
+ noop_visit_use_tree(use_tree, self);
+ }
+
+ fn flat_map_foreign_item(&mut self, ni: P<ForeignItem>) -> SmallVec<[P<ForeignItem>; 1]> {
+ noop_flat_map_foreign_item(ni, self)
+ }
+
+ fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
+ noop_flat_map_item(i, self)
+ }
+
+ fn visit_fn_header(&mut self, header: &mut FnHeader) {
+ noop_visit_fn_header(header, self);
+ }
+
+ fn flat_map_field_def(&mut self, fd: FieldDef) -> SmallVec<[FieldDef; 1]> {
+ noop_flat_map_field_def(fd, self)
+ }
+
+ fn visit_item_kind(&mut self, i: &mut ItemKind) {
+ noop_visit_item_kind(i, self);
+ }
+
+ fn flat_map_trait_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
+ noop_flat_map_assoc_item(i, self)
+ }
+
+ fn flat_map_impl_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
+ noop_flat_map_assoc_item(i, self)
+ }
+
+ fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
+ noop_visit_fn_decl(d, self);
+ }
+
+ fn visit_asyncness(&mut self, a: &mut Async) {
+ noop_visit_asyncness(a, self);
+ }
+
+ fn visit_closure_binder(&mut self, b: &mut ClosureBinder) {
+ noop_visit_closure_binder(b, self);
+ }
+
+ fn visit_block(&mut self, b: &mut P<Block>) {
+ noop_visit_block(b, self);
+ }
+
+ fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
+ noop_flat_map_stmt(s, self)
+ }
+
+ fn flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]> {
+ noop_flat_map_arm(arm, self)
+ }
+
+ fn visit_pat(&mut self, p: &mut P<Pat>) {
+ noop_visit_pat(p, self);
+ }
+
+ fn visit_anon_const(&mut self, c: &mut AnonConst) {
+ noop_visit_anon_const(c, self);
+ }
+
+ fn visit_expr(&mut self, e: &mut P<Expr>) {
+ noop_visit_expr(e, self);
+ }
+
+ fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
+ noop_filter_map_expr(e, self)
+ }
+
+ fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
+ noop_visit_generic_arg(arg, self);
+ }
+
+ fn visit_ty(&mut self, t: &mut P<Ty>) {
+ noop_visit_ty(t, self);
+ }
+
+ fn visit_lifetime(&mut self, l: &mut Lifetime) {
+ noop_visit_lifetime(l, self);
+ }
+
+ fn visit_constraint(&mut self, t: &mut AssocConstraint) {
+ noop_visit_constraint(t, self);
+ }
+
+ fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
+ noop_visit_foreign_mod(nm, self);
+ }
+
+ fn flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]> {
+ noop_flat_map_variant(v, self)
+ }
+
+ fn visit_ident(&mut self, i: &mut Ident) {
+ noop_visit_ident(i, self);
+ }
+
+ fn visit_path(&mut self, p: &mut Path) {
+ noop_visit_path(p, self);
+ }
+
+ fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
+ noop_visit_qself(qs, self);
+ }
+
+ fn visit_generic_args(&mut self, p: &mut GenericArgs) {
+ noop_visit_generic_args(p, self);
+ }
+
+ fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
+ noop_visit_angle_bracketed_parameter_data(p, self);
+ }
+
+ fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
+ noop_visit_parenthesized_parameter_data(p, self);
+ }
+
+ fn visit_local(&mut self, l: &mut P<Local>) {
+ noop_visit_local(l, self);
+ }
+
+ fn visit_mac_call(&mut self, mac: &mut MacCall) {
+ noop_visit_mac(mac, self);
+ }
+
+ fn visit_macro_def(&mut self, def: &mut MacroDef) {
+ noop_visit_macro_def(def, self);
+ }
+
+ fn visit_label(&mut self, label: &mut Label) {
+ noop_visit_label(label, self);
+ }
+
+ fn visit_attribute(&mut self, at: &mut Attribute) {
+ noop_visit_attribute(at, self);
+ }
+
+ fn flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]> {
+ noop_flat_map_param(param, self)
+ }
+
+ fn visit_generics(&mut self, generics: &mut Generics) {
+ noop_visit_generics(generics, self);
+ }
+
+ fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
+ noop_visit_trait_ref(tr, self);
+ }
+
+ fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
+ noop_visit_poly_trait_ref(p, self);
+ }
+
+ fn visit_variant_data(&mut self, vdata: &mut VariantData) {
+ noop_visit_variant_data(vdata, self);
+ }
+
+ fn flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]> {
+ noop_flat_map_generic_param(param, self)
+ }
+
+ fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
+ noop_visit_param_bound(tpb, self);
+ }
+
+ fn visit_mt(&mut self, mt: &mut MutTy) {
+ noop_visit_mt(mt, self);
+ }
+
+ fn flat_map_expr_field(&mut self, f: ExprField) -> SmallVec<[ExprField; 1]> {
+ noop_flat_map_expr_field(f, self)
+ }
+
+ fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
+ noop_visit_where_clause(where_clause, self);
+ }
+
+ fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
+ noop_visit_where_predicate(where_predicate, self);
+ }
+
+ fn visit_vis(&mut self, vis: &mut Visibility) {
+ noop_visit_vis(vis, self);
+ }
+
+ fn visit_id(&mut self, _id: &mut NodeId) {
+ // Do nothing.
+ }
+
+ fn visit_span(&mut self, _sp: &mut Span) {
+ // Do nothing.
+ }
+
+ fn flat_map_pat_field(&mut self, fp: PatField) -> SmallVec<[PatField; 1]> {
+ noop_flat_map_pat_field(fp, self)
+ }
+
+ fn visit_inline_asm(&mut self, asm: &mut InlineAsm) {
+ noop_visit_inline_asm(asm, self)
+ }
+
+ fn visit_inline_asm_sym(&mut self, sym: &mut InlineAsmSym) {
+ noop_visit_inline_asm_sym(sym, self)
+ }
+}
+
+/// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
+/// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
+/// method.
+//
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_clobber<T: DummyAstNode>(t: &mut T, f: impl FnOnce(T) -> T) {
+ unsafe {
+ // Safe because `t` is used in a read-only fashion by `read()` before
+ // being overwritten by `write()`.
+ let old_t = ptr::read(t);
+ let new_t =
+ panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t))).unwrap_or_else(|err| {
+ // Set `t` to some valid but possible meaningless value,
+ // and pass the fatal error further.
+ ptr::write(t, T::dummy());
+ panic::resume_unwind(err);
+ });
+ ptr::write(t, new_t);
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+#[inline]
+pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
+where
+ F: FnMut(&mut T),
+{
+ for elem in elems {
+ visit_elem(elem);
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+#[inline]
+pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
+where
+ F: FnMut(&mut T),
+{
+ if let Some(elem) = opt {
+ visit_elem(elem);
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
+ visit_vec(attrs, |attr| vis.visit_attribute(attr));
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
+ for attr in attrs.iter_mut() {
+ vis.visit_attribute(attr);
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
+ exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
+ visit_vec(bounds, |bound| vis.visit_param_bound(bound));
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
+ vis.visit_fn_header(header);
+ vis.visit_fn_decl(decl);
+ vis.visit_span(span);
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_mac_args<T: MutVisitor>(args: &mut MacArgs, vis: &mut T) {
+ match args {
+ MacArgs::Empty => {}
+ MacArgs::Delimited(dspan, _delim, tokens) => {
+ visit_delim_span(dspan, vis);
+ visit_tts(tokens, vis);
+ }
+ MacArgs::Eq(eq_span, MacArgsEq::Ast(expr)) => {
+ vis.visit_span(eq_span);
+ vis.visit_expr(expr);
+ }
+ MacArgs::Eq(_, MacArgsEq::Hir(lit)) => {
+ unreachable!("in literal form when visiting mac args eq: {:?}", lit)
+ }
+ }
+}
+
+pub fn visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T) {
+ vis.visit_span(&mut dspan.open);
+ vis.visit_span(&mut dspan.close);
+}
+
+pub fn noop_flat_map_pat_field<T: MutVisitor>(
+ mut fp: PatField,
+ vis: &mut T,
+) -> SmallVec<[PatField; 1]> {
+ let PatField { attrs, id, ident, is_placeholder: _, is_shorthand: _, pat, span } = &mut fp;
+ vis.visit_id(id);
+ vis.visit_ident(ident);
+ vis.visit_pat(pat);
+ vis.visit_span(span);
+ visit_thin_attrs(attrs, vis);
+ smallvec![fp]
+}
+
+pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
+ let UseTree { prefix, kind, span } = use_tree;
+ vis.visit_path(prefix);
+ match kind {
+ UseTreeKind::Simple(rename, id1, id2) => {
+ visit_opt(rename, |rename| vis.visit_ident(rename));
+ vis.visit_id(id1);
+ vis.visit_id(id2);
+ }
+ UseTreeKind::Nested(items) => {
+ for (tree, id) in items {
+ vis.visit_use_tree(tree);
+ vis.visit_id(id);
+ }
+ }
+ UseTreeKind::Glob => {}
+ }
+ vis.visit_span(span);
+}
+
+pub fn noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]> {
+ let Arm { attrs, pat, guard, body, span, id, is_placeholder: _ } = &mut arm;
+ visit_thin_attrs(attrs, vis);
+ vis.visit_id(id);
+ vis.visit_pat(pat);
+ visit_opt(guard, |guard| vis.visit_expr(guard));
+ vis.visit_expr(body);
+ vis.visit_span(span);
+ smallvec![arm]
+}
+
+pub fn noop_visit_constraint<T: MutVisitor>(
+ AssocConstraint { id, ident, gen_args, kind, span }: &mut AssocConstraint,
+ vis: &mut T,
+) {
+ vis.visit_id(id);
+ vis.visit_ident(ident);
+ if let Some(ref mut gen_args) = gen_args {
+ vis.visit_generic_args(gen_args);
+ }
+ match kind {
+ AssocConstraintKind::Equality { ref mut term } => match term {
+ Term::Ty(ty) => vis.visit_ty(ty),
+ Term::Const(c) => vis.visit_anon_const(c),
+ },
+ AssocConstraintKind::Bound { ref mut bounds } => visit_bounds(bounds, vis),
+ }
+ vis.visit_span(span);
+}
+
+pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
+ let Ty { id, kind, span, tokens } = ty.deref_mut();
+ vis.visit_id(id);
+ match kind {
+ TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never | TyKind::CVarArgs => {}
+ TyKind::Slice(ty) => vis.visit_ty(ty),
+ TyKind::Ptr(mt) => vis.visit_mt(mt),
+ TyKind::Rptr(lt, mt) => {
+ visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
+ vis.visit_mt(mt);
+ }
+ TyKind::BareFn(bft) => {
+ let BareFnTy { unsafety, ext: _, generic_params, decl, decl_span } = bft.deref_mut();
+ visit_unsafety(unsafety, vis);
+ generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
+ vis.visit_fn_decl(decl);
+ vis.visit_span(decl_span);
+ }
+ TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
+ TyKind::Paren(ty) => vis.visit_ty(ty),
+ TyKind::Path(qself, path) => {
+ vis.visit_qself(qself);
+ vis.visit_path(path);
+ }
+ TyKind::Array(ty, length) => {
+ vis.visit_ty(ty);
+ vis.visit_anon_const(length);
+ }
+ TyKind::Typeof(expr) => vis.visit_anon_const(expr),
+ TyKind::TraitObject(bounds, _syntax) => {
+ visit_vec(bounds, |bound| vis.visit_param_bound(bound))
+ }
+ TyKind::ImplTrait(id, bounds) => {
+ vis.visit_id(id);
+ visit_vec(bounds, |bound| vis.visit_param_bound(bound));
+ }
+ TyKind::MacCall(mac) => vis.visit_mac_call(mac),
+ }
+ vis.visit_span(span);
+ visit_lazy_tts(tokens, vis);
+}
+
+pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
+ let ForeignMod { unsafety, abi: _, items } = foreign_mod;
+ visit_unsafety(unsafety, vis);
+ items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
+}
+
+pub fn noop_flat_map_variant<T: MutVisitor>(
+ mut variant: Variant,
+ visitor: &mut T,
+) -> SmallVec<[Variant; 1]> {
+ let Variant { ident, vis, attrs, id, data, disr_expr, span, is_placeholder: _ } = &mut variant;
+ visitor.visit_ident(ident);
+ visitor.visit_vis(vis);
+ visit_thin_attrs(attrs, visitor);
+ visitor.visit_id(id);
+ visitor.visit_variant_data(data);
+ visit_opt(disr_expr, |disr_expr| visitor.visit_anon_const(disr_expr));
+ visitor.visit_span(span);
+ smallvec![variant]
+}
+
+pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
+ vis.visit_span(span);
+}
+
+pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
+ vis.visit_span(span);
+ for PathSegment { ident, id, args } in segments {
+ vis.visit_ident(ident);
+ vis.visit_id(id);
+ visit_opt(args, |args| vis.visit_generic_args(args));
+ }
+ visit_lazy_tts(tokens, vis);
+}
+
+pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
+ visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
+ vis.visit_ty(ty);
+ vis.visit_span(path_span);
+ })
+}
+
+pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
+ match generic_args {
+ GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
+ GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
+ }
+}
+
+pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
+ match arg {
+ GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
+ GenericArg::Type(ty) => vis.visit_ty(ty),
+ GenericArg::Const(ct) => vis.visit_anon_const(ct),
+ }
+}
+
+pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
+ data: &mut AngleBracketedArgs,
+ vis: &mut T,
+) {
+ let AngleBracketedArgs { args, span } = data;
+ visit_vec(args, |arg| match arg {
+ AngleBracketedArg::Arg(arg) => vis.visit_generic_arg(arg),
+ AngleBracketedArg::Constraint(constraint) => vis.visit_constraint(constraint),
+ });
+ vis.visit_span(span);
+}
+
+pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
+ args: &mut ParenthesizedArgs,
+ vis: &mut T,
+) {
+ let ParenthesizedArgs { inputs, output, span, .. } = args;
+ visit_vec(inputs, |input| vis.visit_ty(input));
+ noop_visit_fn_ret_ty(output, vis);
+ vis.visit_span(span);
+}
+
+pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
+ let Local { id, pat, ty, kind, span, attrs, tokens } = local.deref_mut();
+ vis.visit_id(id);
+ vis.visit_pat(pat);
+ visit_opt(ty, |ty| vis.visit_ty(ty));
+ match kind {
+ LocalKind::Decl => {}
+ LocalKind::Init(init) => {
+ vis.visit_expr(init);
+ }
+ LocalKind::InitElse(init, els) => {
+ vis.visit_expr(init);
+ vis.visit_block(els);
+ }
+ }
+ vis.visit_span(span);
+ visit_thin_attrs(attrs, vis);
+ visit_lazy_tts(tokens, vis);
+}
+
+pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
+ let Attribute { kind, id: _, style: _, span } = attr;
+ match kind {
+ AttrKind::Normal(AttrItem { path, args, tokens }, attr_tokens) => {
+ vis.visit_path(path);
+ visit_mac_args(args, vis);
+ visit_lazy_tts(tokens, vis);
+ visit_lazy_tts(attr_tokens, vis);
+ }
+ AttrKind::DocComment(..) => {}
+ }
+ vis.visit_span(span);
+}
+
+pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
+ let MacCall { path, args, prior_type_ascription: _ } = mac;
+ vis.visit_path(path);
+ visit_mac_args(args, vis);
+}
+
+pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
+ let MacroDef { body, macro_rules: _ } = macro_def;
+ visit_mac_args(body, vis);
+}
+
+pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
+ match li {
+ NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
+ NestedMetaItem::Literal(_lit) => {}
+ }
+}
+
+pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
+ let MetaItem { path: _, kind, span } = mi;
+ match kind {
+ MetaItemKind::Word => {}
+ MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
+ MetaItemKind::NameValue(_s) => {}
+ }
+ vis.visit_span(span);
+}
+
+pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
+ let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
+ vis.visit_id(id);
+ visit_thin_attrs(attrs, vis);
+ vis.visit_pat(pat);
+ vis.visit_span(span);
+ vis.visit_ty(ty);
+ smallvec![param]
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_attr_annotated_tt<T: MutVisitor>(tt: &mut AttrAnnotatedTokenTree, vis: &mut T) {
+ match tt {
+ AttrAnnotatedTokenTree::Token(token) => {
+ visit_token(token, vis);
+ }
+ AttrAnnotatedTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
+ vis.visit_span(open);
+ vis.visit_span(close);
+ visit_attr_annotated_tts(tts, vis);
+ }
+ AttrAnnotatedTokenTree::Attributes(data) => {
+ for attr in &mut *data.attrs {
+ match &mut attr.kind {
+ AttrKind::Normal(_, attr_tokens) => {
+ visit_lazy_tts(attr_tokens, vis);
+ }
+ AttrKind::DocComment(..) => {
+ vis.visit_span(&mut attr.span);
+ }
+ }
+ }
+ visit_lazy_tts_opt_mut(Some(&mut data.tokens), vis);
+ }
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
+ match tt {
+ TokenTree::Token(token, _) => {
+ visit_token(token, vis);
+ }
+ TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
+ vis.visit_span(open);
+ vis.visit_span(close);
+ visit_tts(tts, vis);
+ }
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
+ if T::VISIT_TOKENS && !tts.is_empty() {
+ let tts = Lrc::make_mut(tts);
+ visit_vec(tts, |tree| visit_tt(tree, vis));
+ }
+}
+
+pub fn visit_attr_annotated_tts<T: MutVisitor>(
+ AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream,
+ vis: &mut T,
+) {
+ if T::VISIT_TOKENS && !tts.is_empty() {
+ let tts = Lrc::make_mut(tts);
+ visit_vec(tts, |(tree, _is_joint)| visit_attr_annotated_tt(tree, vis));
+ }
+}
+
+pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T) {
+ if T::VISIT_TOKENS {
+ if let Some(lazy_tts) = lazy_tts {
+ let mut tts = lazy_tts.create_token_stream();
+ visit_attr_annotated_tts(&mut tts, vis);
+ *lazy_tts = LazyTokenStream::new(tts);
+ }
+ }
+}
+
+pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T) {
+ visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+// Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
+// In practice the ident part is not actually used by specific visitors right now,
+// but there's a test below checking that it works.
+pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
+ let Token { kind, span } = t;
+ match kind {
+ token::Ident(name, _) | token::Lifetime(name) => {
+ let mut ident = Ident::new(*name, *span);
+ vis.visit_ident(&mut ident);
+ *name = ident.name;
+ *span = ident.span;
+ return; // Avoid visiting the span for the second time.
+ }
+ token::Interpolated(nt) => {
+ let mut nt = Lrc::make_mut(nt);
+ visit_nonterminal(&mut nt, vis);
+ }
+ _ => {}
+ }
+ vis.visit_span(span);
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+/// Applies the visitor to elements of interpolated nodes.
+//
+// N.B., this can occur only when applying a visitor to partially expanded
+// code, where parsed pieces have gotten implanted ito *other* macro
+// invocations. This is relevant for macro hygiene, but possibly not elsewhere.
+//
+// One problem here occurs because the types for flat_map_item, flat_map_stmt,
+// etc., allow the visitor to return *multiple* items; this is a problem for the
+// nodes here, because they insist on having exactly one piece. One solution
+// would be to mangle the MutVisitor trait to include one-to-many and
+// one-to-one versions of these entry points, but that would probably confuse a
+// lot of people and help very few. Instead, I'm just going to put in dynamic
+// checks. I think the performance impact of this will be pretty much
+// nonexistent. The danger is that someone will apply a `MutVisitor` to a
+// partially expanded node, and will be confused by the fact that their
+// `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
+// nodes. Hopefully they'll wind up reading this comment, and doing something
+// appropriate.
+//
+// BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
+// contain multiple items, but decided against it when I looked at
+// `parse_item_or_view_item` and tried to figure out what I would do with
+// multiple items there....
+pub fn visit_nonterminal<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
+ match nt {
+ token::NtItem(item) => visit_clobber(item, |item| {
+ // This is probably okay, because the only visitors likely to
+ // peek inside interpolated nodes will be renamings/markings,
+ // which map single items to single items.
+ vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
+ }),
+ token::NtBlock(block) => vis.visit_block(block),
+ token::NtStmt(stmt) => visit_clobber(stmt, |stmt| {
+ // See reasoning above.
+ stmt.map(|stmt| {
+ vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
+ })
+ }),
+ token::NtPat(pat) => vis.visit_pat(pat),
+ token::NtExpr(expr) => vis.visit_expr(expr),
+ token::NtTy(ty) => vis.visit_ty(ty),
+ token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
+ token::NtLifetime(ident) => vis.visit_ident(ident),
+ token::NtLiteral(expr) => vis.visit_expr(expr),
+ token::NtMeta(item) => {
+ let AttrItem { path, args, tokens } = item.deref_mut();
+ vis.visit_path(path);
+ visit_mac_args(args, vis);
+ visit_lazy_tts(tokens, vis);
+ }
+ token::NtPath(path) => vis.visit_path(path),
+ token::NtVis(visib) => vis.visit_vis(visib),
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut T) {
+ match defaultness {
+ Defaultness::Default(span) => vis.visit_span(span),
+ Defaultness::Final => {}
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
+ match unsafety {
+ Unsafe::Yes(span) => vis.visit_span(span),
+ Unsafe::No => {}
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
+ match polarity {
+ ImplPolarity::Positive => {}
+ ImplPolarity::Negative(span) => vis.visit_span(span),
+ }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T) {
+ match constness {
+ Const::Yes(span) => vis.visit_span(span),
+ Const::No => {}
+ }
+}
+
+pub fn noop_visit_closure_binder<T: MutVisitor>(binder: &mut ClosureBinder, vis: &mut T) {
+ match binder {
+ ClosureBinder::NotPresent => {}
+ ClosureBinder::For { span: _, generic_params } => {
+ let mut vec = std::mem::take(generic_params).into_vec();
+ vec.flat_map_in_place(|param| vis.flat_map_generic_param(param));
+ *generic_params = P::from_vec(vec);
+ }
+ }
+}
+
+pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
+ match asyncness {
+ Async::Yes { span: _, closure_id, return_impl_trait_id } => {
+ vis.visit_id(closure_id);
+ vis.visit_id(return_impl_trait_id);
+ }
+ Async::No => {}
+ }
+}
+
+pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
+ let FnDecl { inputs, output } = decl.deref_mut();
+ inputs.flat_map_in_place(|param| vis.flat_map_param(param));
+ noop_visit_fn_ret_ty(output, vis);
+}
+
+pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
+ match fn_ret_ty {
+ FnRetTy::Default(span) => vis.visit_span(span),
+ FnRetTy::Ty(ty) => vis.visit_ty(ty),
+ }
+}
+
+pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
+ match pb {
+ GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
+ GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
+ }
+}
+
+pub fn noop_flat_map_generic_param<T: MutVisitor>(
+ mut param: GenericParam,
+ vis: &mut T,
+) -> SmallVec<[GenericParam; 1]> {
+ let GenericParam { id, ident, attrs, bounds, kind, colon_span, is_placeholder: _ } = &mut param;
+ vis.visit_id(id);
+ vis.visit_ident(ident);
+ if let Some(ref mut colon_span) = colon_span {
+ vis.visit_span(colon_span);
+ }
+ visit_thin_attrs(attrs, vis);
+ visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
+ match kind {
+ GenericParamKind::Lifetime => {}
+ GenericParamKind::Type { default } => {
+ visit_opt(default, |default| vis.visit_ty(default));
+ }
+ GenericParamKind::Const { ty, kw_span: _, default } => {
+ vis.visit_ty(ty);
+ visit_opt(default, |default| vis.visit_anon_const(default));
+ }
+ }
+ smallvec![param]
+}
+
+pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
+ vis.visit_ident(ident);
+}
+
+fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
+ vis.visit_id(id);
+ vis.visit_ident(ident);
+}
+
+pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
+ let Generics { params, where_clause, span } = generics;
+ params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
+ vis.visit_where_clause(where_clause);
+ vis.visit_span(span);
+}
+
+pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
+ let WhereClause { has_where_token: _, predicates, span } = wc;
+ visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
+ vis.visit_span(span);
+}
+
+pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
+ match pred {
+ WherePredicate::BoundPredicate(bp) => {
+ let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
+ vis.visit_span(span);
+ bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
+ vis.visit_ty(bounded_ty);
+ visit_vec(bounds, |bound| vis.visit_param_bound(bound));
+ }
+ WherePredicate::RegionPredicate(rp) => {
+ let WhereRegionPredicate { span, lifetime, bounds } = rp;
+ vis.visit_span(span);
+ noop_visit_lifetime(lifetime, vis);
+ visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
+ }
+ WherePredicate::EqPredicate(ep) => {
+ let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
+ vis.visit_id(id);
+ vis.visit_span(span);
+ vis.visit_ty(lhs_ty);
+ vis.visit_ty(rhs_ty);
+ }
+ }
+}
+
+pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
+ match vdata {
+ VariantData::Struct(fields, ..) => {
+ fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
+ }
+ VariantData::Tuple(fields, id) => {
+ fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
+ vis.visit_id(id);
+ }
+ VariantData::Unit(id) => vis.visit_id(id),
+ }
+}
+
+pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
+ vis.visit_path(path);
+ vis.visit_id(ref_id);
+}
+
+pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
+ let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
+ bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
+ vis.visit_trait_ref(trait_ref);
+ vis.visit_span(span);
+}
+
+pub fn noop_flat_map_field_def<T: MutVisitor>(
+ mut fd: FieldDef,
+ visitor: &mut T,
+) -> SmallVec<[FieldDef; 1]> {
+ let FieldDef { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut fd;
+ visitor.visit_span(span);
+ visit_opt(ident, |ident| visitor.visit_ident(ident));
+ visitor.visit_vis(vis);
+ visitor.visit_id(id);
+ visitor.visit_ty(ty);
+ visit_thin_attrs(attrs, visitor);
+ smallvec![fd]
+}
+
+pub fn noop_flat_map_expr_field<T: MutVisitor>(
+ mut f: ExprField,
+ vis: &mut T,
+) -> SmallVec<[ExprField; 1]> {
+ let ExprField { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
+ vis.visit_ident(ident);
+ vis.visit_expr(expr);
+ vis.visit_id(id);
+ vis.visit_span(span);
+ visit_thin_attrs(attrs, vis);
+ smallvec![f]
+}
+
+pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
+ vis.visit_ty(ty);
+}
+
+pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
+ let Block { id, stmts, rules: _, span, tokens, could_be_bare_literal: _ } = block.deref_mut();
+ vis.visit_id(id);
+ stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
+ vis.visit_span(span);
+ visit_lazy_tts(tokens, vis);
+}
+
+pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
+ match kind {
+ ItemKind::ExternCrate(_orig_name) => {}
+ ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
+ ItemKind::Static(ty, _, expr) => {
+ vis.visit_ty(ty);
+ visit_opt(expr, |expr| vis.visit_expr(expr));
+ }
+ ItemKind::Const(defaultness, ty, expr) => {
+ visit_defaultness(defaultness, vis);
+ vis.visit_ty(ty);
+ visit_opt(expr, |expr| vis.visit_expr(expr));
+ }
+ ItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
+ visit_defaultness(defaultness, vis);
+ visit_fn_sig(sig, vis);
+ vis.visit_generics(generics);
+ visit_opt(body, |body| vis.visit_block(body));
+ }
+ ItemKind::Mod(unsafety, mod_kind) => {
+ visit_unsafety(unsafety, vis);
+ match mod_kind {
+ ModKind::Loaded(items, _inline, ModSpans { inner_span, inject_use_span }) => {
+ vis.visit_span(inner_span);
+ vis.visit_span(inject_use_span);
+ items.flat_map_in_place(|item| vis.flat_map_item(item));
+ }
+ ModKind::Unloaded => {}
+ }
+ }
+ ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
+ ItemKind::GlobalAsm(asm) => vis.visit_inline_asm(asm),
+ ItemKind::TyAlias(box TyAlias {
+ defaultness, generics, where_clauses, bounds, ty, ..
+ }) => {
+ visit_defaultness(defaultness, vis);
+ vis.visit_generics(generics);
+ vis.visit_span(&mut where_clauses.0.1);
+ vis.visit_span(&mut where_clauses.1.1);
+ visit_bounds(bounds, vis);
+ visit_opt(ty, |ty| vis.visit_ty(ty));
+ }
+ ItemKind::Enum(EnumDef { variants }, generics) => {
+ variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
+ vis.visit_generics(generics);
+ }
+ ItemKind::Struct(variant_data, generics) | ItemKind::Union(variant_data, generics) => {
+ vis.visit_variant_data(variant_data);
+ vis.visit_generics(generics);
+ }
+ ItemKind::Impl(box Impl {
+ defaultness,
+ unsafety,
+ generics,
+ constness,
+ polarity,
+ of_trait,
+ self_ty,
+ items,
+ }) => {
+ visit_defaultness(defaultness, vis);
+ visit_unsafety(unsafety, vis);
+ vis.visit_generics(generics);
+ visit_constness(constness, vis);
+ visit_polarity(polarity, vis);
+ visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
+ vis.visit_ty(self_ty);
+ items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
+ }
+ ItemKind::Trait(box Trait { unsafety, is_auto: _, generics, bounds, items }) => {
+ visit_unsafety(unsafety, vis);
+ vis.visit_generics(generics);
+ visit_bounds(bounds, vis);
+ items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
+ }
+ ItemKind::TraitAlias(generics, bounds) => {
+ vis.visit_generics(generics);
+ visit_bounds(bounds, vis);
+ }
+ ItemKind::MacCall(m) => vis.visit_mac_call(m),
+ ItemKind::MacroDef(def) => vis.visit_macro_def(def),
+ }
+}
+
+pub fn noop_flat_map_assoc_item<T: MutVisitor>(
+ mut item: P<AssocItem>,
+ visitor: &mut T,
+) -> SmallVec<[P<AssocItem>; 1]> {
+ let Item { id, ident, vis, attrs, kind, span, tokens } = item.deref_mut();
+ visitor.visit_id(id);
+ visitor.visit_ident(ident);
+ visitor.visit_vis(vis);
+ visit_attrs(attrs, visitor);
+ match kind {
+ AssocItemKind::Const(defaultness, ty, expr) => {
+ visit_defaultness(defaultness, visitor);
+ visitor.visit_ty(ty);
+ visit_opt(expr, |expr| visitor.visit_expr(expr));
+ }
+ AssocItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
+ visit_defaultness(defaultness, visitor);
+ visitor.visit_generics(generics);
+ visit_fn_sig(sig, visitor);
+ visit_opt(body, |body| visitor.visit_block(body));
+ }
+ AssocItemKind::TyAlias(box TyAlias {
+ defaultness,
+ generics,
+ where_clauses,
+ bounds,
+ ty,
+ ..
+ }) => {
+ visit_defaultness(defaultness, visitor);
+ visitor.visit_generics(generics);
+ visitor.visit_span(&mut where_clauses.0.1);
+ visitor.visit_span(&mut where_clauses.1.1);
+ visit_bounds(bounds, visitor);
+ visit_opt(ty, |ty| visitor.visit_ty(ty));
+ }
+ AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
+ }
+ visitor.visit_span(span);
+ visit_lazy_tts(tokens, visitor);
+ smallvec![item]
+}
+
+pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
+ let FnHeader { unsafety, asyncness, constness, ext: _ } = header;
+ visit_constness(constness, vis);
+ vis.visit_asyncness(asyncness);
+ visit_unsafety(unsafety, vis);
+}
+
+pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
+ let Crate { attrs, items, spans, id, is_placeholder: _ } = krate;
+ vis.visit_id(id);
+ visit_attrs(attrs, vis);
+ items.flat_map_in_place(|item| vis.flat_map_item(item));
+ let ModSpans { inner_span, inject_use_span } = spans;
+ vis.visit_span(inner_span);
+ vis.visit_span(inject_use_span);
+}
+
+// Mutates one item into possibly many items.
+pub fn noop_flat_map_item<T: MutVisitor>(
+ mut item: P<Item>,
+ visitor: &mut T,
+) -> SmallVec<[P<Item>; 1]> {
+ let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
+ visitor.visit_ident(ident);
+ visit_attrs(attrs, visitor);
+ visitor.visit_id(id);
+ visitor.visit_item_kind(kind);
+ visitor.visit_vis(vis);
+ visitor.visit_span(span);
+ visit_lazy_tts(tokens, visitor);
+
+ smallvec![item]
+}
+
+pub fn noop_flat_map_foreign_item<T: MutVisitor>(
+ mut item: P<ForeignItem>,
+ visitor: &mut T,
+) -> SmallVec<[P<ForeignItem>; 1]> {
+ let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
+ visitor.visit_id(id);
+ visitor.visit_ident(ident);
+ visitor.visit_vis(vis);
+ visit_attrs(attrs, visitor);
+ match kind {
+ ForeignItemKind::Static(ty, _, expr) => {
+ visitor.visit_ty(ty);
+ visit_opt(expr, |expr| visitor.visit_expr(expr));
+ }
+ ForeignItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
+ visit_defaultness(defaultness, visitor);
+ visitor.visit_generics(generics);
+ visit_fn_sig(sig, visitor);
+ visit_opt(body, |body| visitor.visit_block(body));
+ }
+ ForeignItemKind::TyAlias(box TyAlias {
+ defaultness,
+ generics,
+ where_clauses,
+ bounds,
+ ty,
+ ..
+ }) => {
+ visit_defaultness(defaultness, visitor);
+ visitor.visit_generics(generics);
+ visitor.visit_span(&mut where_clauses.0.1);
+ visitor.visit_span(&mut where_clauses.1.1);
+ visit_bounds(bounds, visitor);
+ visit_opt(ty, |ty| visitor.visit_ty(ty));
+ }
+ ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
+ }
+ visitor.visit_span(span);
+ visit_lazy_tts(tokens, visitor);
+ smallvec![item]
+}
+
+pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
+ let Pat { id, kind, span, tokens } = pat.deref_mut();
+ vis.visit_id(id);
+ match kind {
+ PatKind::Wild | PatKind::Rest => {}
+ PatKind::Ident(_binding_mode, ident, sub) => {
+ vis.visit_ident(ident);
+ visit_opt(sub, |sub| vis.visit_pat(sub));
+ }
+ PatKind::Lit(e) => vis.visit_expr(e),
+ PatKind::TupleStruct(qself, path, elems) => {
+ vis.visit_qself(qself);
+ vis.visit_path(path);
+ visit_vec(elems, |elem| vis.visit_pat(elem));
+ }
+ PatKind::Path(qself, path) => {
+ vis.visit_qself(qself);
+ vis.visit_path(path);
+ }
+ PatKind::Struct(qself, path, fields, _etc) => {
+ vis.visit_qself(qself);
+ vis.visit_path(path);
+ fields.flat_map_in_place(|field| vis.flat_map_pat_field(field));
+ }
+ PatKind::Box(inner) => vis.visit_pat(inner),
+ PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
+ PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
+ visit_opt(e1, |e| vis.visit_expr(e));
+ visit_opt(e2, |e| vis.visit_expr(e));
+ vis.visit_span(span);
+ }
+ PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
+ visit_vec(elems, |elem| vis.visit_pat(elem))
+ }
+ PatKind::Paren(inner) => vis.visit_pat(inner),
+ PatKind::MacCall(mac) => vis.visit_mac_call(mac),
+ }
+ vis.visit_span(span);
+ visit_lazy_tts(tokens, vis);
+}
+
+pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
+ vis.visit_id(id);
+ vis.visit_expr(value);
+}
+
+pub fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
+ for (op, _) in &mut asm.operands {
+ match op {
+ InlineAsmOperand::In { expr, .. }
+ | InlineAsmOperand::Out { expr: Some(expr), .. }
+ | InlineAsmOperand::InOut { expr, .. } => vis.visit_expr(expr),
+ InlineAsmOperand::Out { expr: None, .. } => {}
+ InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
+ vis.visit_expr(in_expr);
+ if let Some(out_expr) = out_expr {
+ vis.visit_expr(out_expr);
+ }
+ }
+ InlineAsmOperand::Const { anon_const } => vis.visit_anon_const(anon_const),
+ InlineAsmOperand::Sym { sym } => vis.visit_inline_asm_sym(sym),
+ }
+ }
+}
+
+pub fn noop_visit_inline_asm_sym<T: MutVisitor>(
+ InlineAsmSym { id, qself, path }: &mut InlineAsmSym,
+ vis: &mut T,
+) {
+ vis.visit_id(id);
+ vis.visit_qself(qself);
+ vis.visit_path(path);
+}
+
+pub fn noop_visit_expr<T: MutVisitor>(
+ Expr { kind, id, span, attrs, tokens }: &mut Expr,
+ vis: &mut T,
+) {
+ match kind {
+ ExprKind::Box(expr) => vis.visit_expr(expr),
+ ExprKind::Array(exprs) => visit_exprs(exprs, vis),
+ ExprKind::ConstBlock(anon_const) => {
+ vis.visit_anon_const(anon_const);
+ }
+ ExprKind::Repeat(expr, count) => {
+ vis.visit_expr(expr);
+ vis.visit_anon_const(count);
+ }
+ ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
+ ExprKind::Call(f, args) => {
+ vis.visit_expr(f);
+ visit_exprs(args, vis);
+ }
+ ExprKind::MethodCall(PathSegment { ident, id, args }, exprs, span) => {
+ vis.visit_ident(ident);
+ vis.visit_id(id);
+ visit_opt(args, |args| vis.visit_generic_args(args));
+ visit_exprs(exprs, vis);
+ vis.visit_span(span);
+ }
+ ExprKind::Binary(_binop, lhs, rhs) => {
+ vis.visit_expr(lhs);
+ vis.visit_expr(rhs);
+ }
+ ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
+ ExprKind::Cast(expr, ty) => {
+ vis.visit_expr(expr);
+ vis.visit_ty(ty);
+ }
+ ExprKind::Type(expr, ty) => {
+ vis.visit_expr(expr);
+ vis.visit_ty(ty);
+ }
+ ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
+ ExprKind::Let(pat, scrutinee, _) => {
+ vis.visit_pat(pat);
+ vis.visit_expr(scrutinee);
+ }
+ ExprKind::If(cond, tr, fl) => {
+ vis.visit_expr(cond);
+ vis.visit_block(tr);
+ visit_opt(fl, |fl| vis.visit_expr(fl));
+ }
+ ExprKind::While(cond, body, label) => {
+ vis.visit_expr(cond);
+ vis.visit_block(body);
+ visit_opt(label, |label| vis.visit_label(label));
+ }
+ ExprKind::ForLoop(pat, iter, body, label) => {
+ vis.visit_pat(pat);
+ vis.visit_expr(iter);
+ vis.visit_block(body);
+ visit_opt(label, |label| vis.visit_label(label));
+ }
+ ExprKind::Loop(body, label) => {
+ vis.visit_block(body);
+ visit_opt(label, |label| vis.visit_label(label));
+ }
+ ExprKind::Match(expr, arms) => {
+ vis.visit_expr(expr);
+ arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
+ }
+ ExprKind::Closure(binder, _capture_by, asyncness, _movability, decl, body, span) => {
+ vis.visit_closure_binder(binder);
+ vis.visit_asyncness(asyncness);
+ vis.visit_fn_decl(decl);
+ vis.visit_expr(body);
+ vis.visit_span(span);
+ }
+ ExprKind::Block(blk, label) => {
+ vis.visit_block(blk);
+ visit_opt(label, |label| vis.visit_label(label));
+ }
+ ExprKind::Async(_capture_by, node_id, body) => {
+ vis.visit_id(node_id);
+ vis.visit_block(body);
+ }
+ ExprKind::Await(expr) => vis.visit_expr(expr),
+ ExprKind::Assign(el, er, _) => {
+ vis.visit_expr(el);
+ vis.visit_expr(er);
+ }
+ ExprKind::AssignOp(_op, el, er) => {
+ vis.visit_expr(el);
+ vis.visit_expr(er);
+ }
+ ExprKind::Field(el, ident) => {
+ vis.visit_expr(el);
+ vis.visit_ident(ident);
+ }
+ ExprKind::Index(el, er) => {
+ vis.visit_expr(el);
+ vis.visit_expr(er);
+ }
+ ExprKind::Range(e1, e2, _lim) => {
+ visit_opt(e1, |e1| vis.visit_expr(e1));
+ visit_opt(e2, |e2| vis.visit_expr(e2));
+ }
+ ExprKind::Underscore => {}
+ ExprKind::Path(qself, path) => {
+ vis.visit_qself(qself);
+ vis.visit_path(path);
+ }
+ ExprKind::Break(label, expr) => {
+ visit_opt(label, |label| vis.visit_label(label));
+ visit_opt(expr, |expr| vis.visit_expr(expr));
+ }
+ ExprKind::Continue(label) => {
+ visit_opt(label, |label| vis.visit_label(label));
+ }
+ ExprKind::Ret(expr) => {
+ visit_opt(expr, |expr| vis.visit_expr(expr));
+ }
+ ExprKind::Yeet(expr) => {
+ visit_opt(expr, |expr| vis.visit_expr(expr));
+ }
+ ExprKind::InlineAsm(asm) => vis.visit_inline_asm(asm),
+ ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
+ ExprKind::Struct(se) => {
+ let StructExpr { qself, path, fields, rest } = se.deref_mut();
+ vis.visit_qself(qself);
+ vis.visit_path(path);
+ fields.flat_map_in_place(|field| vis.flat_map_expr_field(field));
+ match rest {
+ StructRest::Base(expr) => vis.visit_expr(expr),
+ StructRest::Rest(_span) => {}
+ StructRest::None => {}
+ }
+ }
+ ExprKind::Paren(expr) => {
+ vis.visit_expr(expr);
+ }
+ ExprKind::Yield(expr) => {
+ visit_opt(expr, |expr| vis.visit_expr(expr));
+ }
+ ExprKind::Try(expr) => vis.visit_expr(expr),
+ ExprKind::TryBlock(body) => vis.visit_block(body),
+ ExprKind::Lit(_) | ExprKind::Err => {}
+ }
+ vis.visit_id(id);
+ vis.visit_span(span);
+ visit_thin_attrs(attrs, vis);
+ visit_lazy_tts(tokens, vis);
+}
+
+pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
+ Some({
+ vis.visit_expr(&mut e);
+ e
+ })
+}
+
+pub fn noop_flat_map_stmt<T: MutVisitor>(
+ Stmt { kind, mut span, mut id }: Stmt,
+ vis: &mut T,
+) -> SmallVec<[Stmt; 1]> {
+ vis.visit_id(&mut id);
+ vis.visit_span(&mut span);
+ let stmts: SmallVec<_> = noop_flat_map_stmt_kind(kind, vis)
+ .into_iter()
+ .map(|kind| Stmt { id, kind, span })
+ .collect();
+ if stmts.len() > 1 {
+ panic!(
+ "cloning statement `NodeId`s is prohibited by default, \
+ the visitor should implement custom statement visiting"
+ );
+ }
+ stmts
+}
+
+pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
+ kind: StmtKind,
+ vis: &mut T,
+) -> SmallVec<[StmtKind; 1]> {
+ match kind {
+ StmtKind::Local(mut local) => smallvec![StmtKind::Local({
+ vis.visit_local(&mut local);
+ local
+ })],
+ StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
+ StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
+ StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
+ StmtKind::Empty => smallvec![StmtKind::Empty],
+ StmtKind::MacCall(mut mac) => {
+ let MacCallStmt { mac: mac_, style: _, attrs, tokens } = mac.deref_mut();
+ vis.visit_mac_call(mac_);
+ visit_thin_attrs(attrs, vis);
+ visit_lazy_tts(tokens, vis);
+ smallvec![StmtKind::MacCall(mac)]
+ }
+ }
+}
+
+pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
+ match &mut visibility.kind {
+ VisibilityKind::Public | VisibilityKind::Inherited => {}
+ VisibilityKind::Restricted { path, id } => {
+ vis.visit_path(path);
+ vis.visit_id(id);
+ }
+ }
+ vis.visit_span(&mut visibility.span);
+}
+
+/// Some value for the AST node that is valid but possibly meaningless.
+pub trait DummyAstNode {
+ fn dummy() -> Self;
+}
+
+impl<T> DummyAstNode for Option<T> {
+ fn dummy() -> Self {
+ Default::default()
+ }
+}
+
+impl<T: DummyAstNode + 'static> DummyAstNode for P<T> {
+ fn dummy() -> Self {
+ P(DummyAstNode::dummy())
+ }
+}
+
+impl<T> DummyAstNode for ThinVec<T> {
+ fn dummy() -> Self {
+ Default::default()
+ }
+}
+
+impl DummyAstNode for Item {
+ fn dummy() -> Self {
+ Item {
+ attrs: Default::default(),
+ id: DUMMY_NODE_ID,
+ span: Default::default(),
+ vis: Visibility {
+ kind: VisibilityKind::Public,
+ span: Default::default(),
+ tokens: Default::default(),
+ },
+ ident: Ident::empty(),
+ kind: ItemKind::ExternCrate(None),
+ tokens: Default::default(),
+ }
+ }
+}
+
+impl DummyAstNode for Expr {
+ fn dummy() -> Self {
+ Expr {
+ id: DUMMY_NODE_ID,
+ kind: ExprKind::Err,
+ span: Default::default(),
+ attrs: Default::default(),
+ tokens: Default::default(),
+ }
+ }
+}
+
+impl DummyAstNode for Ty {
+ fn dummy() -> Self {
+ Ty {
+ id: DUMMY_NODE_ID,
+ kind: TyKind::Err,
+ span: Default::default(),
+ tokens: Default::default(),
+ }
+ }
+}
+
+impl DummyAstNode for Pat {
+ fn dummy() -> Self {
+ Pat {
+ id: DUMMY_NODE_ID,
+ kind: PatKind::Wild,
+ span: Default::default(),
+ tokens: Default::default(),
+ }
+ }
+}
+
+impl DummyAstNode for Stmt {
+ fn dummy() -> Self {
+ Stmt { id: DUMMY_NODE_ID, kind: StmtKind::Empty, span: Default::default() }
+ }
+}
+
+impl DummyAstNode for Block {
+ fn dummy() -> Self {
+ Block {
+ stmts: Default::default(),
+ id: DUMMY_NODE_ID,
+ rules: BlockCheckMode::Default,
+ span: Default::default(),
+ tokens: Default::default(),
+ could_be_bare_literal: Default::default(),
+ }
+ }
+}
+
+impl DummyAstNode for Crate {
+ fn dummy() -> Self {
+ Crate {
+ attrs: Default::default(),
+ items: Default::default(),
+ spans: Default::default(),
+ id: DUMMY_NODE_ID,
+ is_placeholder: Default::default(),
+ }
+ }
+}
diff --git a/compiler/rustc_ast/src/node_id.rs b/compiler/rustc_ast/src/node_id.rs
new file mode 100644
index 000000000..7f928cb57
--- /dev/null
+++ b/compiler/rustc_ast/src/node_id.rs
@@ -0,0 +1,40 @@
+use rustc_span::LocalExpnId;
+use std::fmt;
+
+rustc_index::newtype_index! {
+ /// Identifies an AST node.
+ ///
+ /// This identifies top-level definitions, expressions, and everything in between.
+ /// This is later turned into [`DefId`] and `HirId` for the HIR.
+ ///
+ /// [`DefId`]: rustc_span::def_id::DefId
+ pub struct NodeId {
+ DEBUG_FORMAT = "NodeId({})"
+ }
+}
+
+rustc_data_structures::define_id_collections!(NodeMap, NodeSet, NodeId);
+
+/// The [`NodeId`] used to represent the root of the crate.
+pub const CRATE_NODE_ID: NodeId = NodeId::from_u32(0);
+
+/// When parsing and at the beginning of doing expansions, we initially give all AST nodes
+/// this dummy AST [`NodeId`]. Then, during a later phase of expansion, we renumber them
+/// to have small, positive IDs.
+pub const DUMMY_NODE_ID: NodeId = NodeId::MAX;
+
+impl NodeId {
+ pub fn placeholder_from_expn_id(expn_id: LocalExpnId) -> Self {
+ NodeId::from_u32(expn_id.as_u32())
+ }
+
+ pub fn placeholder_to_expn_id(self) -> LocalExpnId {
+ LocalExpnId::from_u32(self.as_u32())
+ }
+}
+
+impl fmt::Display for NodeId {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Display::fmt(&self.as_u32(), f)
+ }
+}
diff --git a/compiler/rustc_ast/src/ptr.rs b/compiler/rustc_ast/src/ptr.rs
new file mode 100644
index 000000000..30481eddf
--- /dev/null
+++ b/compiler/rustc_ast/src/ptr.rs
@@ -0,0 +1,212 @@
+//! The AST pointer.
+//!
+//! Provides `P<T>`, a frozen owned smart pointer.
+//!
+//! # Motivations and benefits
+//!
+//! * **Identity**: sharing AST nodes is problematic for the various analysis
+//! passes (e.g., one may be able to bypass the borrow checker with a shared
+//! `ExprKind::AddrOf` node taking a mutable borrow).
+//!
+//! * **Immutability**: `P<T>` disallows mutating its inner `T`, unlike `Box<T>`
+//! (unless it contains an `Unsafe` interior, but that may be denied later).
+//! This mainly prevents mistakes, but also enforces a kind of "purity".
+//!
+//! * **Efficiency**: folding can reuse allocation space for `P<T>` and `Vec<T>`,
+//! the latter even when the input and output types differ (as it would be the
+//! case with arenas or a GADT AST using type parameters to toggle features).
+//!
+//! * **Maintainability**: `P<T>` provides a fixed interface - `Deref`,
+//! `and_then` and `map` - which can remain fully functional even if the
+//! implementation changes (using a special thread-local heap, for example).
+//! Moreover, a switch to, e.g., `P<'a, T>` would be easy and mostly automated.
+
+use std::fmt::{self, Debug, Display};
+use std::iter::FromIterator;
+use std::ops::{Deref, DerefMut};
+use std::{slice, vec};
+
+use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
+
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+/// An owned smart pointer.
+pub struct P<T: ?Sized> {
+ ptr: Box<T>,
+}
+
+/// Construct a `P<T>` from a `T` value.
+#[allow(non_snake_case)]
+pub fn P<T: 'static>(value: T) -> P<T> {
+ P { ptr: Box::new(value) }
+}
+
+impl<T: 'static> P<T> {
+ /// Move out of the pointer.
+ /// Intended for chaining transformations not covered by `map`.
+ pub fn and_then<U, F>(self, f: F) -> U
+ where
+ F: FnOnce(T) -> U,
+ {
+ f(*self.ptr)
+ }
+
+ /// Equivalent to `and_then(|x| x)`.
+ pub fn into_inner(self) -> T {
+ *self.ptr
+ }
+
+ /// Produce a new `P<T>` from `self` without reallocating.
+ pub fn map<F>(mut self, f: F) -> P<T>
+ where
+ F: FnOnce(T) -> T,
+ {
+ let x = f(*self.ptr);
+ *self.ptr = x;
+
+ self
+ }
+
+ /// Optionally produce a new `P<T>` from `self` without reallocating.
+ pub fn filter_map<F>(mut self, f: F) -> Option<P<T>>
+ where
+ F: FnOnce(T) -> Option<T>,
+ {
+ *self.ptr = f(*self.ptr)?;
+ Some(self)
+ }
+}
+
+impl<T: ?Sized> Deref for P<T> {
+ type Target = T;
+
+ fn deref(&self) -> &T {
+ &self.ptr
+ }
+}
+
+impl<T: ?Sized> DerefMut for P<T> {
+ fn deref_mut(&mut self) -> &mut T {
+ &mut self.ptr
+ }
+}
+
+impl<T: 'static + Clone> Clone for P<T> {
+ fn clone(&self) -> P<T> {
+ P((**self).clone())
+ }
+}
+
+impl<T: ?Sized + Debug> Debug for P<T> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ Debug::fmt(&self.ptr, f)
+ }
+}
+
+impl<T: Display> Display for P<T> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ Display::fmt(&**self, f)
+ }
+}
+
+impl<T> fmt::Pointer for P<T> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Pointer::fmt(&self.ptr, f)
+ }
+}
+
+impl<D: Decoder, T: 'static + Decodable<D>> Decodable<D> for P<T> {
+ fn decode(d: &mut D) -> P<T> {
+ P(Decodable::decode(d))
+ }
+}
+
+impl<S: Encoder, T: Encodable<S>> Encodable<S> for P<T> {
+ fn encode(&self, s: &mut S) {
+ (**self).encode(s);
+ }
+}
+
+impl<T> P<[T]> {
+ pub const fn new() -> P<[T]> {
+ P { ptr: Box::default() }
+ }
+
+ #[inline(never)]
+ pub fn from_vec(v: Vec<T>) -> P<[T]> {
+ P { ptr: v.into_boxed_slice() }
+ }
+
+ #[inline(never)]
+ pub fn into_vec(self) -> Vec<T> {
+ self.ptr.into_vec()
+ }
+}
+
+impl<T> Default for P<[T]> {
+ /// Creates an empty `P<[T]>`.
+ fn default() -> P<[T]> {
+ P::new()
+ }
+}
+
+impl<T: Clone> Clone for P<[T]> {
+ fn clone(&self) -> P<[T]> {
+ P::from_vec(self.to_vec())
+ }
+}
+
+impl<T> From<Vec<T>> for P<[T]> {
+ fn from(v: Vec<T>) -> Self {
+ P::from_vec(v)
+ }
+}
+
+impl<T> Into<Vec<T>> for P<[T]> {
+ fn into(self) -> Vec<T> {
+ self.into_vec()
+ }
+}
+
+impl<T> FromIterator<T> for P<[T]> {
+ fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> P<[T]> {
+ P::from_vec(iter.into_iter().collect())
+ }
+}
+
+impl<T> IntoIterator for P<[T]> {
+ type Item = T;
+ type IntoIter = vec::IntoIter<T>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ self.into_vec().into_iter()
+ }
+}
+
+impl<'a, T> IntoIterator for &'a P<[T]> {
+ type Item = &'a T;
+ type IntoIter = slice::Iter<'a, T>;
+ fn into_iter(self) -> Self::IntoIter {
+ self.ptr.into_iter()
+ }
+}
+
+impl<S: Encoder, T: Encodable<S>> Encodable<S> for P<[T]> {
+ fn encode(&self, s: &mut S) {
+ Encodable::encode(&**self, s);
+ }
+}
+
+impl<D: Decoder, T: Decodable<D>> Decodable<D> for P<[T]> {
+ fn decode(d: &mut D) -> P<[T]> {
+ P::from_vec(Decodable::decode(d))
+ }
+}
+
+impl<CTX, T> HashStable<CTX> for P<T>
+where
+ T: ?Sized + HashStable<CTX>,
+{
+ fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
+ (**self).hash_stable(hcx, hasher);
+ }
+}
diff --git a/compiler/rustc_ast/src/token.rs b/compiler/rustc_ast/src/token.rs
new file mode 100644
index 000000000..85d9687c6
--- /dev/null
+++ b/compiler/rustc_ast/src/token.rs
@@ -0,0 +1,851 @@
+pub use BinOpToken::*;
+pub use LitKind::*;
+pub use Nonterminal::*;
+pub use TokenKind::*;
+
+use crate::ast;
+use crate::ptr::P;
+
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::sync::Lrc;
+use rustc_macros::HashStable_Generic;
+use rustc_span::symbol::{kw, sym};
+use rustc_span::symbol::{Ident, Symbol};
+use rustc_span::{self, edition::Edition, Span, DUMMY_SP};
+use std::borrow::Cow;
+use std::{fmt, mem};
+
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum CommentKind {
+ Line,
+ Block,
+}
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Hash, Debug, Copy)]
+#[derive(HashStable_Generic)]
+pub enum BinOpToken {
+ Plus,
+ Minus,
+ Star,
+ Slash,
+ Percent,
+ Caret,
+ And,
+ Or,
+ Shl,
+ Shr,
+}
+
+/// Describes how a sequence of token trees is delimited.
+/// Cannot use `proc_macro::Delimiter` directly because this
+/// structure should implement some additional traits.
+/// The `None` variant is also renamed to `Invisible` to be
+/// less confusing and better convey the semantics.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Encodable, Decodable, Hash, HashStable_Generic)]
+pub enum Delimiter {
+ /// `( ... )`
+ Parenthesis,
+ /// `{ ... }`
+ Brace,
+ /// `[ ... ]`
+ Bracket,
+ /// `Ø ... Ø`
+ /// An invisible delimiter, that may, for example, appear around tokens coming from a
+ /// "macro variable" `$var`. It is important to preserve operator priorities in cases like
+ /// `$var * 3` where `$var` is `1 + 2`.
+ /// Invisible delimiters might not survive roundtrip of a token stream through a string.
+ Invisible,
+}
+
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum LitKind {
+ Bool, // AST only, must never appear in a `Token`
+ Byte,
+ Char,
+ Integer,
+ Float,
+ Str,
+ StrRaw(u8), // raw string delimited by `n` hash symbols
+ ByteStr,
+ ByteStrRaw(u8), // raw byte string delimited by `n` hash symbols
+ Err,
+}
+
+/// A literal token.
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub struct Lit {
+ pub kind: LitKind,
+ pub symbol: Symbol,
+ pub suffix: Option<Symbol>,
+}
+
+impl fmt::Display for Lit {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ let Lit { kind, symbol, suffix } = *self;
+ match kind {
+ Byte => write!(f, "b'{}'", symbol)?,
+ Char => write!(f, "'{}'", symbol)?,
+ Str => write!(f, "\"{}\"", symbol)?,
+ StrRaw(n) => write!(
+ f,
+ "r{delim}\"{string}\"{delim}",
+ delim = "#".repeat(n as usize),
+ string = symbol
+ )?,
+ ByteStr => write!(f, "b\"{}\"", symbol)?,
+ ByteStrRaw(n) => write!(
+ f,
+ "br{delim}\"{string}\"{delim}",
+ delim = "#".repeat(n as usize),
+ string = symbol
+ )?,
+ Integer | Float | Bool | Err => write!(f, "{}", symbol)?,
+ }
+
+ if let Some(suffix) = suffix {
+ write!(f, "{}", suffix)?;
+ }
+
+ Ok(())
+ }
+}
+
+impl LitKind {
+ /// An English article for the literal token kind.
+ pub fn article(self) -> &'static str {
+ match self {
+ Integer | Err => "an",
+ _ => "a",
+ }
+ }
+
+ pub fn descr(self) -> &'static str {
+ match self {
+ Bool => panic!("literal token contains `Lit::Bool`"),
+ Byte => "byte",
+ Char => "char",
+ Integer => "integer",
+ Float => "float",
+ Str | StrRaw(..) => "string",
+ ByteStr | ByteStrRaw(..) => "byte string",
+ Err => "error",
+ }
+ }
+
+ pub(crate) fn may_have_suffix(self) -> bool {
+ matches!(self, Integer | Float | Err)
+ }
+}
+
+impl Lit {
+ pub fn new(kind: LitKind, symbol: Symbol, suffix: Option<Symbol>) -> Lit {
+ Lit { kind, symbol, suffix }
+ }
+}
+
+pub fn ident_can_begin_expr(name: Symbol, span: Span, is_raw: bool) -> bool {
+ let ident_token = Token::new(Ident(name, is_raw), span);
+
+ !ident_token.is_reserved_ident()
+ || ident_token.is_path_segment_keyword()
+ || [
+ kw::Async,
+ kw::Do,
+ kw::Box,
+ kw::Break,
+ kw::Const,
+ kw::Continue,
+ kw::False,
+ kw::For,
+ kw::If,
+ kw::Let,
+ kw::Loop,
+ kw::Match,
+ kw::Move,
+ kw::Return,
+ kw::True,
+ kw::Try,
+ kw::Unsafe,
+ kw::While,
+ kw::Yield,
+ kw::Static,
+ ]
+ .contains(&name)
+}
+
+fn ident_can_begin_type(name: Symbol, span: Span, is_raw: bool) -> bool {
+ let ident_token = Token::new(Ident(name, is_raw), span);
+
+ !ident_token.is_reserved_ident()
+ || ident_token.is_path_segment_keyword()
+ || [kw::Underscore, kw::For, kw::Impl, kw::Fn, kw::Unsafe, kw::Extern, kw::Typeof, kw::Dyn]
+ .contains(&name)
+}
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum TokenKind {
+ /* Expression-operator symbols. */
+ Eq,
+ Lt,
+ Le,
+ EqEq,
+ Ne,
+ Ge,
+ Gt,
+ AndAnd,
+ OrOr,
+ Not,
+ Tilde,
+ BinOp(BinOpToken),
+ BinOpEq(BinOpToken),
+
+ /* Structural symbols */
+ At,
+ Dot,
+ DotDot,
+ DotDotDot,
+ DotDotEq,
+ Comma,
+ Semi,
+ Colon,
+ ModSep,
+ RArrow,
+ LArrow,
+ FatArrow,
+ Pound,
+ Dollar,
+ Question,
+ /// Used by proc macros for representing lifetimes, not generated by lexer right now.
+ SingleQuote,
+ /// An opening delimiter (e.g., `{`).
+ OpenDelim(Delimiter),
+ /// A closing delimiter (e.g., `}`).
+ CloseDelim(Delimiter),
+
+ /* Literals */
+ Literal(Lit),
+
+ /// Identifier token.
+ /// Do not forget about `NtIdent` when you want to match on identifiers.
+ /// It's recommended to use `Token::(ident,uninterpolate,uninterpolated_span)` to
+ /// treat regular and interpolated identifiers in the same way.
+ Ident(Symbol, /* is_raw */ bool),
+ /// Lifetime identifier token.
+ /// Do not forget about `NtLifetime` when you want to match on lifetime identifiers.
+ /// It's recommended to use `Token::(lifetime,uninterpolate,uninterpolated_span)` to
+ /// treat regular and interpolated lifetime identifiers in the same way.
+ Lifetime(Symbol),
+
+ /// An embedded AST node, as produced by a macro. This only exists for
+ /// historical reasons. We'd like to get rid of it, for multiple reasons.
+ /// - It's conceptually very strange. Saying a token can contain an AST
+ /// node is like saying, in natural language, that a word can contain a
+ /// sentence.
+ /// - It requires special handling in a bunch of places in the parser.
+ /// - It prevents `Token` from implementing `Copy`.
+ /// It adds complexity and likely slows things down. Please don't add new
+ /// occurrences of this token kind!
+ Interpolated(Lrc<Nonterminal>),
+
+ /// A doc comment token.
+ /// `Symbol` is the doc comment's data excluding its "quotes" (`///`, `/**`, etc)
+ /// similarly to symbols in string literal tokens.
+ DocComment(CommentKind, ast::AttrStyle, Symbol),
+
+ Eof,
+}
+
+// `TokenKind` is used a lot. Make sure it doesn't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+rustc_data_structures::static_assert_size!(TokenKind, 16);
+
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
+pub struct Token {
+ pub kind: TokenKind,
+ pub span: Span,
+}
+
+impl TokenKind {
+ pub fn lit(kind: LitKind, symbol: Symbol, suffix: Option<Symbol>) -> TokenKind {
+ Literal(Lit::new(kind, symbol, suffix))
+ }
+
+ // An approximation to proc-macro-style single-character operators used by rustc parser.
+ // If the operator token can be broken into two tokens, the first of which is single-character,
+ // then this function performs that operation, otherwise it returns `None`.
+ pub fn break_two_token_op(&self) -> Option<(TokenKind, TokenKind)> {
+ Some(match *self {
+ Le => (Lt, Eq),
+ EqEq => (Eq, Eq),
+ Ne => (Not, Eq),
+ Ge => (Gt, Eq),
+ AndAnd => (BinOp(And), BinOp(And)),
+ OrOr => (BinOp(Or), BinOp(Or)),
+ BinOp(Shl) => (Lt, Lt),
+ BinOp(Shr) => (Gt, Gt),
+ BinOpEq(Plus) => (BinOp(Plus), Eq),
+ BinOpEq(Minus) => (BinOp(Minus), Eq),
+ BinOpEq(Star) => (BinOp(Star), Eq),
+ BinOpEq(Slash) => (BinOp(Slash), Eq),
+ BinOpEq(Percent) => (BinOp(Percent), Eq),
+ BinOpEq(Caret) => (BinOp(Caret), Eq),
+ BinOpEq(And) => (BinOp(And), Eq),
+ BinOpEq(Or) => (BinOp(Or), Eq),
+ BinOpEq(Shl) => (Lt, Le),
+ BinOpEq(Shr) => (Gt, Ge),
+ DotDot => (Dot, Dot),
+ DotDotDot => (Dot, DotDot),
+ ModSep => (Colon, Colon),
+ RArrow => (BinOp(Minus), Gt),
+ LArrow => (Lt, BinOp(Minus)),
+ FatArrow => (Eq, Gt),
+ _ => return None,
+ })
+ }
+
+ /// Returns tokens that are likely to be typed accidentally instead of the current token.
+ /// Enables better error recovery when the wrong token is found.
+ pub fn similar_tokens(&self) -> Option<Vec<TokenKind>> {
+ match *self {
+ Comma => Some(vec![Dot, Lt, Semi]),
+ Semi => Some(vec![Colon, Comma]),
+ FatArrow => Some(vec![Eq, RArrow]),
+ _ => None,
+ }
+ }
+
+ pub fn should_end_const_arg(&self) -> bool {
+ matches!(self, Gt | Ge | BinOp(Shr) | BinOpEq(Shr))
+ }
+}
+
+impl Token {
+ pub fn new(kind: TokenKind, span: Span) -> Self {
+ Token { kind, span }
+ }
+
+ /// Some token that will be thrown away later.
+ pub fn dummy() -> Self {
+ Token::new(TokenKind::Question, DUMMY_SP)
+ }
+
+ /// Recovers a `Token` from an `Ident`. This creates a raw identifier if necessary.
+ pub fn from_ast_ident(ident: Ident) -> Self {
+ Token::new(Ident(ident.name, ident.is_raw_guess()), ident.span)
+ }
+
+ /// Return this token by value and leave a dummy token in its place.
+ pub fn take(&mut self) -> Self {
+ mem::replace(self, Token::dummy())
+ }
+
+ /// For interpolated tokens, returns a span of the fragment to which the interpolated
+ /// token refers. For all other tokens this is just a regular span.
+ /// It is particularly important to use this for identifiers and lifetimes
+ /// for which spans affect name resolution and edition checks.
+ /// Note that keywords are also identifiers, so they should use this
+ /// if they keep spans or perform edition checks.
+ pub fn uninterpolated_span(&self) -> Span {
+ match &self.kind {
+ Interpolated(nt) => nt.span(),
+ _ => self.span,
+ }
+ }
+
+ pub fn is_op(&self) -> bool {
+ !matches!(
+ self.kind,
+ OpenDelim(..)
+ | CloseDelim(..)
+ | Literal(..)
+ | DocComment(..)
+ | Ident(..)
+ | Lifetime(..)
+ | Interpolated(..)
+ | Eof
+ )
+ }
+
+ pub fn is_like_plus(&self) -> bool {
+ matches!(self.kind, BinOp(Plus) | BinOpEq(Plus))
+ }
+
+ /// Returns `true` if the token can appear at the start of an expression.
+ pub fn can_begin_expr(&self) -> bool {
+ match self.uninterpolate().kind {
+ Ident(name, is_raw) =>
+ ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
+ OpenDelim(..) | // tuple, array or block
+ Literal(..) | // literal
+ Not | // operator not
+ BinOp(Minus) | // unary minus
+ BinOp(Star) | // dereference
+ BinOp(Or) | OrOr | // closure
+ BinOp(And) | // reference
+ AndAnd | // double reference
+ // DotDotDot is no longer supported, but we need some way to display the error
+ DotDot | DotDotDot | DotDotEq | // range notation
+ Lt | BinOp(Shl) | // associated path
+ ModSep | // global path
+ Lifetime(..) | // labeled loop
+ Pound => true, // expression attributes
+ Interpolated(ref nt) => matches!(**nt, NtLiteral(..) |
+ NtExpr(..) |
+ NtBlock(..) |
+ NtPath(..)),
+ _ => false,
+ }
+ }
+
+ /// Returns `true` if the token can appear at the start of a type.
+ pub fn can_begin_type(&self) -> bool {
+ match self.uninterpolate().kind {
+ Ident(name, is_raw) =>
+ ident_can_begin_type(name, self.span, is_raw), // type name or keyword
+ OpenDelim(Delimiter::Parenthesis) | // tuple
+ OpenDelim(Delimiter::Bracket) | // array
+ Not | // never
+ BinOp(Star) | // raw pointer
+ BinOp(And) | // reference
+ AndAnd | // double reference
+ Question | // maybe bound in trait object
+ Lifetime(..) | // lifetime bound in trait object
+ Lt | BinOp(Shl) | // associated path
+ ModSep => true, // global path
+ Interpolated(ref nt) => matches!(**nt, NtTy(..) | NtPath(..)),
+ _ => false,
+ }
+ }
+
+ /// Returns `true` if the token can appear at the start of a const param.
+ pub fn can_begin_const_arg(&self) -> bool {
+ match self.kind {
+ OpenDelim(Delimiter::Brace) => true,
+ Interpolated(ref nt) => matches!(**nt, NtExpr(..) | NtBlock(..) | NtLiteral(..)),
+ _ => self.can_begin_literal_maybe_minus(),
+ }
+ }
+
+ /// Returns `true` if the token can appear at the start of a generic bound.
+ pub fn can_begin_bound(&self) -> bool {
+ self.is_path_start()
+ || self.is_lifetime()
+ || self.is_keyword(kw::For)
+ || self == &Question
+ || self == &OpenDelim(Delimiter::Parenthesis)
+ }
+
+ /// Returns `true` if the token is any literal.
+ pub fn is_lit(&self) -> bool {
+ matches!(self.kind, Literal(..))
+ }
+
+ /// Returns `true` if the token is any literal, a minus (which can prefix a literal,
+ /// for example a '-42', or one of the boolean idents).
+ ///
+ /// In other words, would this token be a valid start of `parse_literal_maybe_minus`?
+ ///
+ /// Keep this in sync with and `Lit::from_token`, excluding unary negation.
+ pub fn can_begin_literal_maybe_minus(&self) -> bool {
+ match self.uninterpolate().kind {
+ Literal(..) | BinOp(Minus) => true,
+ Ident(name, false) if name.is_bool_lit() => true,
+ Interpolated(ref nt) => match &**nt {
+ NtLiteral(_) => true,
+ NtExpr(e) => match &e.kind {
+ ast::ExprKind::Lit(_) => true,
+ ast::ExprKind::Unary(ast::UnOp::Neg, e) => {
+ matches!(&e.kind, ast::ExprKind::Lit(_))
+ }
+ _ => false,
+ },
+ _ => false,
+ },
+ _ => false,
+ }
+ }
+
+ // A convenience function for matching on identifiers during parsing.
+ // Turns interpolated identifier (`$i: ident`) or lifetime (`$l: lifetime`) token
+ // into the regular identifier or lifetime token it refers to,
+ // otherwise returns the original token.
+ pub fn uninterpolate(&self) -> Cow<'_, Token> {
+ match &self.kind {
+ Interpolated(nt) => match **nt {
+ NtIdent(ident, is_raw) => {
+ Cow::Owned(Token::new(Ident(ident.name, is_raw), ident.span))
+ }
+ NtLifetime(ident) => Cow::Owned(Token::new(Lifetime(ident.name), ident.span)),
+ _ => Cow::Borrowed(self),
+ },
+ _ => Cow::Borrowed(self),
+ }
+ }
+
+ /// Returns an identifier if this token is an identifier.
+ #[inline]
+ pub fn ident(&self) -> Option<(Ident, /* is_raw */ bool)> {
+ // We avoid using `Token::uninterpolate` here because it's slow.
+ match &self.kind {
+ &Ident(name, is_raw) => Some((Ident::new(name, self.span), is_raw)),
+ Interpolated(nt) => match **nt {
+ NtIdent(ident, is_raw) => Some((ident, is_raw)),
+ _ => None,
+ },
+ _ => None,
+ }
+ }
+
+ /// Returns a lifetime identifier if this token is a lifetime.
+ #[inline]
+ pub fn lifetime(&self) -> Option<Ident> {
+ // We avoid using `Token::uninterpolate` here because it's slow.
+ match &self.kind {
+ &Lifetime(name) => Some(Ident::new(name, self.span)),
+ Interpolated(nt) => match **nt {
+ NtLifetime(ident) => Some(ident),
+ _ => None,
+ },
+ _ => None,
+ }
+ }
+
+ /// Returns `true` if the token is an identifier.
+ pub fn is_ident(&self) -> bool {
+ self.ident().is_some()
+ }
+
+ /// Returns `true` if the token is a lifetime.
+ pub fn is_lifetime(&self) -> bool {
+ self.lifetime().is_some()
+ }
+
+ /// Returns `true` if the token is an identifier whose name is the given
+ /// string slice.
+ pub fn is_ident_named(&self, name: Symbol) -> bool {
+ self.ident().map_or(false, |(ident, _)| ident.name == name)
+ }
+
+ /// Returns `true` if the token is an interpolated path.
+ fn is_path(&self) -> bool {
+ if let Interpolated(ref nt) = self.kind && let NtPath(..) = **nt {
+ return true;
+ }
+ false
+ }
+
+ /// Would `maybe_whole_expr` in `parser.rs` return `Ok(..)`?
+ /// That is, is this a pre-parsed expression dropped into the token stream
+ /// (which happens while parsing the result of macro expansion)?
+ pub fn is_whole_expr(&self) -> bool {
+ if let Interpolated(ref nt) = self.kind
+ && let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtBlock(_) = **nt
+ {
+ return true;
+ }
+
+ false
+ }
+
+ // Is the token an interpolated block (`$b:block`)?
+ pub fn is_whole_block(&self) -> bool {
+ if let Interpolated(ref nt) = self.kind && let NtBlock(..) = **nt {
+ return true;
+ }
+ false
+ }
+
+ /// Returns `true` if the token is either the `mut` or `const` keyword.
+ pub fn is_mutability(&self) -> bool {
+ self.is_keyword(kw::Mut) || self.is_keyword(kw::Const)
+ }
+
+ pub fn is_qpath_start(&self) -> bool {
+ self == &Lt || self == &BinOp(Shl)
+ }
+
+ pub fn is_path_start(&self) -> bool {
+ self == &ModSep
+ || self.is_qpath_start()
+ || self.is_path()
+ || self.is_path_segment_keyword()
+ || self.is_ident() && !self.is_reserved_ident()
+ }
+
+ /// Returns `true` if the token is a given keyword, `kw`.
+ pub fn is_keyword(&self, kw: Symbol) -> bool {
+ self.is_non_raw_ident_where(|id| id.name == kw)
+ }
+
+ pub fn is_path_segment_keyword(&self) -> bool {
+ self.is_non_raw_ident_where(Ident::is_path_segment_keyword)
+ }
+
+ // Returns true for reserved identifiers used internally for elided lifetimes,
+ // unnamed method parameters, crate root module, error recovery etc.
+ pub fn is_special_ident(&self) -> bool {
+ self.is_non_raw_ident_where(Ident::is_special)
+ }
+
+ /// Returns `true` if the token is a keyword used in the language.
+ pub fn is_used_keyword(&self) -> bool {
+ self.is_non_raw_ident_where(Ident::is_used_keyword)
+ }
+
+ /// Returns `true` if the token is a keyword reserved for possible future use.
+ pub fn is_unused_keyword(&self) -> bool {
+ self.is_non_raw_ident_where(Ident::is_unused_keyword)
+ }
+
+ /// Returns `true` if the token is either a special identifier or a keyword.
+ pub fn is_reserved_ident(&self) -> bool {
+ self.is_non_raw_ident_where(Ident::is_reserved)
+ }
+
+ /// Returns `true` if the token is the identifier `true` or `false`.
+ pub fn is_bool_lit(&self) -> bool {
+ self.is_non_raw_ident_where(|id| id.name.is_bool_lit())
+ }
+
+ pub fn is_numeric_lit(&self) -> bool {
+ matches!(
+ self.kind,
+ Literal(Lit { kind: LitKind::Integer, .. }) | Literal(Lit { kind: LitKind::Float, .. })
+ )
+ }
+
+ /// Returns `true` if the token is a non-raw identifier for which `pred` holds.
+ pub fn is_non_raw_ident_where(&self, pred: impl FnOnce(Ident) -> bool) -> bool {
+ match self.ident() {
+ Some((id, false)) => pred(id),
+ _ => false,
+ }
+ }
+
+ pub fn glue(&self, joint: &Token) -> Option<Token> {
+ let kind = match self.kind {
+ Eq => match joint.kind {
+ Eq => EqEq,
+ Gt => FatArrow,
+ _ => return None,
+ },
+ Lt => match joint.kind {
+ Eq => Le,
+ Lt => BinOp(Shl),
+ Le => BinOpEq(Shl),
+ BinOp(Minus) => LArrow,
+ _ => return None,
+ },
+ Gt => match joint.kind {
+ Eq => Ge,
+ Gt => BinOp(Shr),
+ Ge => BinOpEq(Shr),
+ _ => return None,
+ },
+ Not => match joint.kind {
+ Eq => Ne,
+ _ => return None,
+ },
+ BinOp(op) => match joint.kind {
+ Eq => BinOpEq(op),
+ BinOp(And) if op == And => AndAnd,
+ BinOp(Or) if op == Or => OrOr,
+ Gt if op == Minus => RArrow,
+ _ => return None,
+ },
+ Dot => match joint.kind {
+ Dot => DotDot,
+ DotDot => DotDotDot,
+ _ => return None,
+ },
+ DotDot => match joint.kind {
+ Dot => DotDotDot,
+ Eq => DotDotEq,
+ _ => return None,
+ },
+ Colon => match joint.kind {
+ Colon => ModSep,
+ _ => return None,
+ },
+ SingleQuote => match joint.kind {
+ Ident(name, false) => Lifetime(Symbol::intern(&format!("'{}", name))),
+ _ => return None,
+ },
+
+ Le | EqEq | Ne | Ge | AndAnd | OrOr | Tilde | BinOpEq(..) | At | DotDotDot
+ | DotDotEq | Comma | Semi | ModSep | RArrow | LArrow | FatArrow | Pound | Dollar
+ | Question | OpenDelim(..) | CloseDelim(..) | Literal(..) | Ident(..)
+ | Lifetime(..) | Interpolated(..) | DocComment(..) | Eof => return None,
+ };
+
+ Some(Token::new(kind, self.span.to(joint.span)))
+ }
+}
+
+impl PartialEq<TokenKind> for Token {
+ fn eq(&self, rhs: &TokenKind) -> bool {
+ self.kind == *rhs
+ }
+}
+
+#[derive(Clone, Encodable, Decodable)]
+/// For interpolation during macro expansion.
+pub enum Nonterminal {
+ NtItem(P<ast::Item>),
+ NtBlock(P<ast::Block>),
+ NtStmt(P<ast::Stmt>),
+ NtPat(P<ast::Pat>),
+ NtExpr(P<ast::Expr>),
+ NtTy(P<ast::Ty>),
+ NtIdent(Ident, /* is_raw */ bool),
+ NtLifetime(Ident),
+ NtLiteral(P<ast::Expr>),
+ /// Stuff inside brackets for attributes
+ NtMeta(P<ast::AttrItem>),
+ NtPath(P<ast::Path>),
+ NtVis(P<ast::Visibility>),
+}
+
+// `Nonterminal` is used a lot. Make sure it doesn't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+rustc_data_structures::static_assert_size!(Nonterminal, 16);
+
+#[derive(Debug, Copy, Clone, PartialEq, Encodable, Decodable)]
+pub enum NonterminalKind {
+ Item,
+ Block,
+ Stmt,
+ PatParam {
+ /// Keep track of whether the user used `:pat_param` or `:pat` and we inferred it from the
+ /// edition of the span. This is used for diagnostics.
+ inferred: bool,
+ },
+ PatWithOr,
+ Expr,
+ Ty,
+ Ident,
+ Lifetime,
+ Literal,
+ Meta,
+ Path,
+ Vis,
+ TT,
+}
+
+impl NonterminalKind {
+ /// The `edition` closure is used to get the edition for the given symbol. Doing
+ /// `span.edition()` is expensive, so we do it lazily.
+ pub fn from_symbol(
+ symbol: Symbol,
+ edition: impl FnOnce() -> Edition,
+ ) -> Option<NonterminalKind> {
+ Some(match symbol {
+ sym::item => NonterminalKind::Item,
+ sym::block => NonterminalKind::Block,
+ sym::stmt => NonterminalKind::Stmt,
+ sym::pat => match edition() {
+ Edition::Edition2015 | Edition::Edition2018 => {
+ NonterminalKind::PatParam { inferred: true }
+ }
+ Edition::Edition2021 | Edition::Edition2024 => NonterminalKind::PatWithOr,
+ },
+ sym::pat_param => NonterminalKind::PatParam { inferred: false },
+ sym::expr => NonterminalKind::Expr,
+ sym::ty => NonterminalKind::Ty,
+ sym::ident => NonterminalKind::Ident,
+ sym::lifetime => NonterminalKind::Lifetime,
+ sym::literal => NonterminalKind::Literal,
+ sym::meta => NonterminalKind::Meta,
+ sym::path => NonterminalKind::Path,
+ sym::vis => NonterminalKind::Vis,
+ sym::tt => NonterminalKind::TT,
+ _ => return None,
+ })
+ }
+ fn symbol(self) -> Symbol {
+ match self {
+ NonterminalKind::Item => sym::item,
+ NonterminalKind::Block => sym::block,
+ NonterminalKind::Stmt => sym::stmt,
+ NonterminalKind::PatParam { inferred: false } => sym::pat_param,
+ NonterminalKind::PatParam { inferred: true } | NonterminalKind::PatWithOr => sym::pat,
+ NonterminalKind::Expr => sym::expr,
+ NonterminalKind::Ty => sym::ty,
+ NonterminalKind::Ident => sym::ident,
+ NonterminalKind::Lifetime => sym::lifetime,
+ NonterminalKind::Literal => sym::literal,
+ NonterminalKind::Meta => sym::meta,
+ NonterminalKind::Path => sym::path,
+ NonterminalKind::Vis => sym::vis,
+ NonterminalKind::TT => sym::tt,
+ }
+ }
+}
+
+impl fmt::Display for NonterminalKind {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "{}", self.symbol())
+ }
+}
+
+impl Nonterminal {
+ pub fn span(&self) -> Span {
+ match self {
+ NtItem(item) => item.span,
+ NtBlock(block) => block.span,
+ NtStmt(stmt) => stmt.span,
+ NtPat(pat) => pat.span,
+ NtExpr(expr) | NtLiteral(expr) => expr.span,
+ NtTy(ty) => ty.span,
+ NtIdent(ident, _) | NtLifetime(ident) => ident.span,
+ NtMeta(attr_item) => attr_item.span(),
+ NtPath(path) => path.span,
+ NtVis(vis) => vis.span,
+ }
+ }
+}
+
+impl PartialEq for Nonterminal {
+ fn eq(&self, rhs: &Self) -> bool {
+ match (self, rhs) {
+ (NtIdent(ident_lhs, is_raw_lhs), NtIdent(ident_rhs, is_raw_rhs)) => {
+ ident_lhs == ident_rhs && is_raw_lhs == is_raw_rhs
+ }
+ (NtLifetime(ident_lhs), NtLifetime(ident_rhs)) => ident_lhs == ident_rhs,
+ // FIXME: Assume that all "complex" nonterminal are not equal, we can't compare them
+ // correctly based on data from AST. This will prevent them from matching each other
+ // in macros. The comparison will become possible only when each nonterminal has an
+ // attached token stream from which it was parsed.
+ _ => false,
+ }
+ }
+}
+
+impl fmt::Debug for Nonterminal {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match *self {
+ NtItem(..) => f.pad("NtItem(..)"),
+ NtBlock(..) => f.pad("NtBlock(..)"),
+ NtStmt(..) => f.pad("NtStmt(..)"),
+ NtPat(..) => f.pad("NtPat(..)"),
+ NtExpr(..) => f.pad("NtExpr(..)"),
+ NtTy(..) => f.pad("NtTy(..)"),
+ NtIdent(..) => f.pad("NtIdent(..)"),
+ NtLiteral(..) => f.pad("NtLiteral(..)"),
+ NtMeta(..) => f.pad("NtMeta(..)"),
+ NtPath(..) => f.pad("NtPath(..)"),
+ NtVis(..) => f.pad("NtVis(..)"),
+ NtLifetime(..) => f.pad("NtLifetime(..)"),
+ }
+ }
+}
+
+impl<CTX> HashStable<CTX> for Nonterminal
+where
+ CTX: crate::HashStableContext,
+{
+ fn hash_stable(&self, _hcx: &mut CTX, _hasher: &mut StableHasher) {
+ panic!("interpolated tokens should not be present in the HIR")
+ }
+}
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
new file mode 100644
index 000000000..9e4a22e1f
--- /dev/null
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -0,0 +1,681 @@
+//! # Token Streams
+//!
+//! `TokenStream`s represent syntactic objects before they are converted into ASTs.
+//! A `TokenStream` is, roughly speaking, a sequence of [`TokenTree`]s,
+//! which are themselves a single [`Token`] or a `Delimited` subsequence of tokens.
+//!
+//! ## Ownership
+//!
+//! `TokenStream`s are persistent data structures constructed as ropes with reference
+//! counted-children. In general, this means that calling an operation on a `TokenStream`
+//! (such as `slice`) produces an entirely new `TokenStream` from the borrowed reference to
+//! the original. This essentially coerces `TokenStream`s into "views" of their subparts,
+//! and a borrowed `TokenStream` is sufficient to build an owned `TokenStream` without taking
+//! ownership of the original.
+
+use crate::ast::StmtKind;
+use crate::ast_traits::{HasAttrs, HasSpan, HasTokens};
+use crate::token::{self, Delimiter, Nonterminal, Token, TokenKind};
+use crate::AttrVec;
+
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::sync::{self, Lrc};
+use rustc_macros::HashStable_Generic;
+use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
+use rustc_span::{Span, DUMMY_SP};
+use smallvec::{smallvec, SmallVec};
+
+use std::{fmt, iter};
+
+/// When the main Rust parser encounters a syntax-extension invocation, it
+/// parses the arguments to the invocation as a token tree. This is a very
+/// loose structure, such that all sorts of different AST fragments can
+/// be passed to syntax extensions using a uniform type.
+///
+/// If the syntax extension is an MBE macro, it will attempt to match its
+/// LHS token tree against the provided token tree, and if it finds a
+/// match, will transcribe the RHS token tree, splicing in any captured
+/// `macro_parser::matched_nonterminals` into the `SubstNt`s it finds.
+///
+/// The RHS of an MBE macro is the only place `SubstNt`s are substituted.
+/// Nothing special happens to misnamed or misplaced `SubstNt`s.
+#[derive(Debug, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
+pub enum TokenTree {
+ /// A single token.
+ Token(Token, Spacing),
+ /// A delimited sequence of token trees.
+ Delimited(DelimSpan, Delimiter, TokenStream),
+}
+
+// This type is used a lot. Make sure it doesn't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+rustc_data_structures::static_assert_size!(TokenTree, 32);
+
+// Ensure all fields of `TokenTree` is `Send` and `Sync`.
+#[cfg(parallel_compiler)]
+fn _dummy()
+where
+ Token: Send + Sync,
+ DelimSpan: Send + Sync,
+ Delimiter: Send + Sync,
+ TokenStream: Send + Sync,
+{
+}
+
+impl TokenTree {
+ /// Checks if this `TokenTree` is equal to the other, regardless of span information.
+ pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
+ match (self, other) {
+ (TokenTree::Token(token, _), TokenTree::Token(token2, _)) => token.kind == token2.kind,
+ (TokenTree::Delimited(_, delim, tts), TokenTree::Delimited(_, delim2, tts2)) => {
+ delim == delim2 && tts.eq_unspanned(&tts2)
+ }
+ _ => false,
+ }
+ }
+
+ /// Retrieves the `TokenTree`'s span.
+ pub fn span(&self) -> Span {
+ match self {
+ TokenTree::Token(token, _) => token.span,
+ TokenTree::Delimited(sp, ..) => sp.entire(),
+ }
+ }
+
+ /// Modify the `TokenTree`'s span in-place.
+ pub fn set_span(&mut self, span: Span) {
+ match self {
+ TokenTree::Token(token, _) => token.span = span,
+ TokenTree::Delimited(dspan, ..) => *dspan = DelimSpan::from_single(span),
+ }
+ }
+
+ // Create a `TokenTree::Token` with alone spacing.
+ pub fn token_alone(kind: TokenKind, span: Span) -> TokenTree {
+ TokenTree::Token(Token::new(kind, span), Spacing::Alone)
+ }
+
+ // Create a `TokenTree::Token` with joint spacing.
+ pub fn token_joint(kind: TokenKind, span: Span) -> TokenTree {
+ TokenTree::Token(Token::new(kind, span), Spacing::Joint)
+ }
+
+ pub fn uninterpolate(self) -> TokenTree {
+ match self {
+ TokenTree::Token(token, spacing) => {
+ TokenTree::Token(token.uninterpolate().into_owned(), spacing)
+ }
+ tt => tt,
+ }
+ }
+}
+
+impl<CTX> HashStable<CTX> for TokenStream
+where
+ CTX: crate::HashStableContext,
+{
+ fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
+ for sub_tt in self.trees() {
+ sub_tt.hash_stable(hcx, hasher);
+ }
+ }
+}
+
+pub trait CreateTokenStream: sync::Send + sync::Sync {
+ fn create_token_stream(&self) -> AttrAnnotatedTokenStream;
+}
+
+impl CreateTokenStream for AttrAnnotatedTokenStream {
+ fn create_token_stream(&self) -> AttrAnnotatedTokenStream {
+ self.clone()
+ }
+}
+
+/// A lazy version of [`TokenStream`], which defers creation
+/// of an actual `TokenStream` until it is needed.
+/// `Box` is here only to reduce the structure size.
+#[derive(Clone)]
+pub struct LazyTokenStream(Lrc<Box<dyn CreateTokenStream>>);
+
+impl LazyTokenStream {
+ pub fn new(inner: impl CreateTokenStream + 'static) -> LazyTokenStream {
+ LazyTokenStream(Lrc::new(Box::new(inner)))
+ }
+
+ pub fn create_token_stream(&self) -> AttrAnnotatedTokenStream {
+ self.0.create_token_stream()
+ }
+}
+
+impl fmt::Debug for LazyTokenStream {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "LazyTokenStream({:?})", self.create_token_stream())
+ }
+}
+
+impl<S: Encoder> Encodable<S> for LazyTokenStream {
+ fn encode(&self, s: &mut S) {
+ // Used by AST json printing.
+ Encodable::encode(&self.create_token_stream(), s);
+ }
+}
+
+impl<D: Decoder> Decodable<D> for LazyTokenStream {
+ fn decode(_d: &mut D) -> Self {
+ panic!("Attempted to decode LazyTokenStream");
+ }
+}
+
+impl<CTX> HashStable<CTX> for LazyTokenStream {
+ fn hash_stable(&self, _hcx: &mut CTX, _hasher: &mut StableHasher) {
+ panic!("Attempted to compute stable hash for LazyTokenStream");
+ }
+}
+
+/// A `AttrAnnotatedTokenStream` is similar to a `TokenStream`, but with extra
+/// information about the tokens for attribute targets. This is used
+/// during expansion to perform early cfg-expansion, and to process attributes
+/// during proc-macro invocations.
+#[derive(Clone, Debug, Default, Encodable, Decodable)]
+pub struct AttrAnnotatedTokenStream(pub Lrc<Vec<(AttrAnnotatedTokenTree, Spacing)>>);
+
+/// Like `TokenTree`, but for `AttrAnnotatedTokenStream`
+#[derive(Clone, Debug, Encodable, Decodable)]
+pub enum AttrAnnotatedTokenTree {
+ Token(Token),
+ Delimited(DelimSpan, Delimiter, AttrAnnotatedTokenStream),
+ /// Stores the attributes for an attribute target,
+ /// along with the tokens for that attribute target.
+ /// See `AttributesData` for more information
+ Attributes(AttributesData),
+}
+
+impl AttrAnnotatedTokenStream {
+ pub fn new(tokens: Vec<(AttrAnnotatedTokenTree, Spacing)>) -> AttrAnnotatedTokenStream {
+ AttrAnnotatedTokenStream(Lrc::new(tokens))
+ }
+
+ /// Converts this `AttrAnnotatedTokenStream` to a plain `TokenStream
+ /// During conversion, `AttrAnnotatedTokenTree::Attributes` get 'flattened'
+ /// back to a `TokenStream` of the form `outer_attr attr_target`.
+ /// If there are inner attributes, they are inserted into the proper
+ /// place in the attribute target tokens.
+ pub fn to_tokenstream(&self) -> TokenStream {
+ let trees: Vec<_> = self
+ .0
+ .iter()
+ .flat_map(|tree| match &tree.0 {
+ AttrAnnotatedTokenTree::Token(inner) => {
+ smallvec![TokenTree::Token(inner.clone(), tree.1)].into_iter()
+ }
+ AttrAnnotatedTokenTree::Delimited(span, delim, stream) => {
+ smallvec![TokenTree::Delimited(*span, *delim, stream.to_tokenstream()),]
+ .into_iter()
+ }
+ AttrAnnotatedTokenTree::Attributes(data) => {
+ let mut outer_attrs = Vec::new();
+ let mut inner_attrs = Vec::new();
+ for attr in &data.attrs {
+ match attr.style {
+ crate::AttrStyle::Outer => {
+ outer_attrs.push(attr);
+ }
+ crate::AttrStyle::Inner => {
+ inner_attrs.push(attr);
+ }
+ }
+ }
+
+ let mut target_tokens: Vec<_> = data
+ .tokens
+ .create_token_stream()
+ .to_tokenstream()
+ .0
+ .iter()
+ .cloned()
+ .collect();
+ if !inner_attrs.is_empty() {
+ let mut found = false;
+ // Check the last two trees (to account for a trailing semi)
+ for tree in target_tokens.iter_mut().rev().take(2) {
+ if let TokenTree::Delimited(span, delim, delim_tokens) = tree {
+ // Inner attributes are only supported on extern blocks, functions, impls,
+ // and modules. All of these have their inner attributes placed at
+ // the beginning of the rightmost outermost braced group:
+ // e.g. fn foo() { #![my_attr} }
+ //
+ // Therefore, we can insert them back into the right location
+ // without needing to do any extra position tracking.
+ //
+ // Note: Outline modules are an exception - they can
+ // have attributes like `#![my_attr]` at the start of a file.
+ // Support for custom attributes in this position is not
+ // properly implemented - we always synthesize fake tokens,
+ // so we never reach this code.
+
+ let mut builder = TokenStreamBuilder::new();
+ for inner_attr in inner_attrs {
+ builder.push(inner_attr.tokens().to_tokenstream());
+ }
+ builder.push(delim_tokens.clone());
+ *tree = TokenTree::Delimited(*span, *delim, builder.build());
+ found = true;
+ break;
+ }
+ }
+
+ assert!(
+ found,
+ "Failed to find trailing delimited group in: {:?}",
+ target_tokens
+ );
+ }
+ let mut flat: SmallVec<[_; 1]> = SmallVec::new();
+ for attr in outer_attrs {
+ // FIXME: Make this more efficient
+ flat.extend(attr.tokens().to_tokenstream().0.clone().iter().cloned());
+ }
+ flat.extend(target_tokens);
+ flat.into_iter()
+ }
+ })
+ .collect();
+ TokenStream::new(trees)
+ }
+}
+
+/// Stores the tokens for an attribute target, along
+/// with its attributes.
+///
+/// This is constructed during parsing when we need to capture
+/// tokens.
+///
+/// For example, `#[cfg(FALSE)] struct Foo {}` would
+/// have an `attrs` field containing the `#[cfg(FALSE)]` attr,
+/// and a `tokens` field storing the (unparsed) tokens `struct Foo {}`
+#[derive(Clone, Debug, Encodable, Decodable)]
+pub struct AttributesData {
+ /// Attributes, both outer and inner.
+ /// These are stored in the original order that they were parsed in.
+ pub attrs: AttrVec,
+ /// The underlying tokens for the attribute target that `attrs`
+ /// are applied to
+ pub tokens: LazyTokenStream,
+}
+
+/// A `TokenStream` is an abstract sequence of tokens, organized into [`TokenTree`]s.
+///
+/// The goal is for procedural macros to work with `TokenStream`s and `TokenTree`s
+/// instead of a representation of the abstract syntax tree.
+/// Today's `TokenTree`s can still contain AST via `token::Interpolated` for
+/// backwards compatibility.
+#[derive(Clone, Debug, Default, Encodable, Decodable)]
+pub struct TokenStream(pub(crate) Lrc<Vec<TokenTree>>);
+
+// `TokenStream` is used a lot. Make sure it doesn't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+rustc_data_structures::static_assert_size!(TokenStream, 8);
+
+#[derive(Clone, Copy, Debug, PartialEq, Encodable, Decodable, HashStable_Generic)]
+pub enum Spacing {
+ Alone,
+ Joint,
+}
+
+impl TokenStream {
+ /// Given a `TokenStream` with a `Stream` of only two arguments, return a new `TokenStream`
+ /// separating the two arguments with a comma for diagnostic suggestions.
+ pub fn add_comma(&self) -> Option<(TokenStream, Span)> {
+ // Used to suggest if a user writes `foo!(a b);`
+ let mut suggestion = None;
+ let mut iter = self.0.iter().enumerate().peekable();
+ while let Some((pos, ts)) = iter.next() {
+ if let Some((_, next)) = iter.peek() {
+ let sp = match (&ts, &next) {
+ (_, TokenTree::Token(Token { kind: token::Comma, .. }, _)) => continue,
+ (
+ TokenTree::Token(token_left, Spacing::Alone),
+ TokenTree::Token(token_right, _),
+ ) if ((token_left.is_ident() && !token_left.is_reserved_ident())
+ || token_left.is_lit())
+ && ((token_right.is_ident() && !token_right.is_reserved_ident())
+ || token_right.is_lit()) =>
+ {
+ token_left.span
+ }
+ (TokenTree::Delimited(sp, ..), _) => sp.entire(),
+ _ => continue,
+ };
+ let sp = sp.shrink_to_hi();
+ let comma = TokenTree::token_alone(token::Comma, sp);
+ suggestion = Some((pos, comma, sp));
+ }
+ }
+ if let Some((pos, comma, sp)) = suggestion {
+ let mut new_stream = Vec::with_capacity(self.0.len() + 1);
+ let parts = self.0.split_at(pos + 1);
+ new_stream.extend_from_slice(parts.0);
+ new_stream.push(comma);
+ new_stream.extend_from_slice(parts.1);
+ return Some((TokenStream::new(new_stream), sp));
+ }
+ None
+ }
+}
+
+impl From<(AttrAnnotatedTokenTree, Spacing)> for AttrAnnotatedTokenStream {
+ fn from((tree, spacing): (AttrAnnotatedTokenTree, Spacing)) -> AttrAnnotatedTokenStream {
+ AttrAnnotatedTokenStream::new(vec![(tree, spacing)])
+ }
+}
+
+impl iter::FromIterator<TokenTree> for TokenStream {
+ fn from_iter<I: IntoIterator<Item = TokenTree>>(iter: I) -> Self {
+ TokenStream::new(iter.into_iter().collect::<Vec<TokenTree>>())
+ }
+}
+
+impl Eq for TokenStream {}
+
+impl PartialEq<TokenStream> for TokenStream {
+ fn eq(&self, other: &TokenStream) -> bool {
+ self.trees().eq(other.trees())
+ }
+}
+
+impl TokenStream {
+ pub fn new(streams: Vec<TokenTree>) -> TokenStream {
+ TokenStream(Lrc::new(streams))
+ }
+
+ pub fn is_empty(&self) -> bool {
+ self.0.is_empty()
+ }
+
+ pub fn len(&self) -> usize {
+ self.0.len()
+ }
+
+ pub fn trees(&self) -> CursorRef<'_> {
+ CursorRef::new(self)
+ }
+
+ pub fn into_trees(self) -> Cursor {
+ Cursor::new(self)
+ }
+
+ /// Compares two `TokenStream`s, checking equality without regarding span information.
+ pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
+ let mut t1 = self.trees();
+ let mut t2 = other.trees();
+ for (t1, t2) in iter::zip(&mut t1, &mut t2) {
+ if !t1.eq_unspanned(&t2) {
+ return false;
+ }
+ }
+ t1.next().is_none() && t2.next().is_none()
+ }
+
+ pub fn map_enumerated<F: FnMut(usize, &TokenTree) -> TokenTree>(self, mut f: F) -> TokenStream {
+ TokenStream(Lrc::new(self.0.iter().enumerate().map(|(i, tree)| f(i, tree)).collect()))
+ }
+
+ fn opt_from_ast(node: &(impl HasAttrs + HasTokens)) -> Option<TokenStream> {
+ let tokens = node.tokens()?;
+ let attrs = node.attrs();
+ let attr_annotated = if attrs.is_empty() {
+ tokens.create_token_stream()
+ } else {
+ let attr_data = AttributesData { attrs: attrs.to_vec().into(), tokens: tokens.clone() };
+ AttrAnnotatedTokenStream::new(vec![(
+ AttrAnnotatedTokenTree::Attributes(attr_data),
+ Spacing::Alone,
+ )])
+ };
+ Some(attr_annotated.to_tokenstream())
+ }
+
+ // Create a token stream containing a single token with alone spacing.
+ pub fn token_alone(kind: TokenKind, span: Span) -> TokenStream {
+ TokenStream::new(vec![TokenTree::token_alone(kind, span)])
+ }
+
+ // Create a token stream containing a single token with joint spacing.
+ pub fn token_joint(kind: TokenKind, span: Span) -> TokenStream {
+ TokenStream::new(vec![TokenTree::token_joint(kind, span)])
+ }
+
+ // Create a token stream containing a single `Delimited`.
+ pub fn delimited(span: DelimSpan, delim: Delimiter, tts: TokenStream) -> TokenStream {
+ TokenStream::new(vec![TokenTree::Delimited(span, delim, tts)])
+ }
+
+ pub fn from_ast(node: &(impl HasAttrs + HasSpan + HasTokens + fmt::Debug)) -> TokenStream {
+ TokenStream::opt_from_ast(node)
+ .unwrap_or_else(|| panic!("missing tokens for node at {:?}: {:?}", node.span(), node))
+ }
+
+ pub fn from_nonterminal_ast(nt: &Nonterminal) -> TokenStream {
+ match nt {
+ Nonterminal::NtIdent(ident, is_raw) => {
+ TokenStream::token_alone(token::Ident(ident.name, *is_raw), ident.span)
+ }
+ Nonterminal::NtLifetime(ident) => {
+ TokenStream::token_alone(token::Lifetime(ident.name), ident.span)
+ }
+ Nonterminal::NtItem(item) => TokenStream::from_ast(item),
+ Nonterminal::NtBlock(block) => TokenStream::from_ast(block),
+ Nonterminal::NtStmt(stmt) if let StmtKind::Empty = stmt.kind => {
+ // FIXME: Properly collect tokens for empty statements.
+ TokenStream::token_alone(token::Semi, stmt.span)
+ }
+ Nonterminal::NtStmt(stmt) => TokenStream::from_ast(stmt),
+ Nonterminal::NtPat(pat) => TokenStream::from_ast(pat),
+ Nonterminal::NtTy(ty) => TokenStream::from_ast(ty),
+ Nonterminal::NtMeta(attr) => TokenStream::from_ast(attr),
+ Nonterminal::NtPath(path) => TokenStream::from_ast(path),
+ Nonterminal::NtVis(vis) => TokenStream::from_ast(vis),
+ Nonterminal::NtExpr(expr) | Nonterminal::NtLiteral(expr) => TokenStream::from_ast(expr),
+ }
+ }
+
+ fn flatten_token(token: &Token, spacing: Spacing) -> TokenTree {
+ match &token.kind {
+ token::Interpolated(nt) if let token::NtIdent(ident, is_raw) = **nt => {
+ TokenTree::Token(Token::new(token::Ident(ident.name, is_raw), ident.span), spacing)
+ }
+ token::Interpolated(nt) => TokenTree::Delimited(
+ DelimSpan::from_single(token.span),
+ Delimiter::Invisible,
+ TokenStream::from_nonterminal_ast(&nt).flattened(),
+ ),
+ _ => TokenTree::Token(token.clone(), spacing),
+ }
+ }
+
+ fn flatten_token_tree(tree: &TokenTree) -> TokenTree {
+ match tree {
+ TokenTree::Token(token, spacing) => TokenStream::flatten_token(token, *spacing),
+ TokenTree::Delimited(span, delim, tts) => {
+ TokenTree::Delimited(*span, *delim, tts.flattened())
+ }
+ }
+ }
+
+ #[must_use]
+ pub fn flattened(&self) -> TokenStream {
+ fn can_skip(stream: &TokenStream) -> bool {
+ stream.trees().all(|tree| match tree {
+ TokenTree::Token(token, _) => !matches!(token.kind, token::Interpolated(_)),
+ TokenTree::Delimited(_, _, inner) => can_skip(inner),
+ })
+ }
+
+ if can_skip(self) {
+ return self.clone();
+ }
+
+ self.trees().map(|tree| TokenStream::flatten_token_tree(tree)).collect()
+ }
+}
+
+// 99.5%+ of the time we have 1 or 2 elements in this vector.
+#[derive(Clone)]
+pub struct TokenStreamBuilder(SmallVec<[TokenStream; 2]>);
+
+impl TokenStreamBuilder {
+ pub fn new() -> TokenStreamBuilder {
+ TokenStreamBuilder(SmallVec::new())
+ }
+
+ pub fn push(&mut self, stream: TokenStream) {
+ self.0.push(stream);
+ }
+
+ pub fn build(self) -> TokenStream {
+ let mut streams = self.0;
+ match streams.len() {
+ 0 => TokenStream::default(),
+ 1 => streams.pop().unwrap(),
+ _ => {
+ // We will extend the first stream in `streams` with the
+ // elements from the subsequent streams. This requires using
+ // `make_mut()` on the first stream, and in practice this
+ // doesn't cause cloning 99.9% of the time.
+ //
+ // One very common use case is when `streams` has two elements,
+ // where the first stream has any number of elements within
+ // (often 1, but sometimes many more) and the second stream has
+ // a single element within.
+
+ // Determine how much the first stream will be extended.
+ // Needed to avoid quadratic blow up from on-the-fly
+ // reallocations (#57735).
+ let num_appends = streams.iter().skip(1).map(|ts| ts.len()).sum();
+
+ // Get the first stream, which will become the result stream.
+ // If it's `None`, create an empty stream.
+ let mut iter = streams.drain(..);
+ let mut res_stream_lrc = iter.next().unwrap().0;
+
+ // Append the subsequent elements to the result stream, after
+ // reserving space for them.
+ let res_vec_mut = Lrc::make_mut(&mut res_stream_lrc);
+ res_vec_mut.reserve(num_appends);
+ for stream in iter {
+ let stream_iter = stream.0.iter().cloned();
+
+ // If (a) `res_mut_vec` is not empty and the last tree
+ // within it is a token tree marked with `Joint`, and (b)
+ // `stream` is not empty and the first tree within it is a
+ // token tree, and (c) the two tokens can be glued
+ // together...
+ if let Some(TokenTree::Token(last_tok, Spacing::Joint)) = res_vec_mut.last()
+ && let Some(TokenTree::Token(tok, spacing)) = stream.0.first()
+ && let Some(glued_tok) = last_tok.glue(&tok)
+ {
+ // ...then overwrite the last token tree in
+ // `res_vec_mut` with the glued token, and skip the
+ // first token tree from `stream`.
+ *res_vec_mut.last_mut().unwrap() = TokenTree::Token(glued_tok, *spacing);
+ res_vec_mut.extend(stream_iter.skip(1));
+ } else {
+ // Append all of `stream`.
+ res_vec_mut.extend(stream_iter);
+ }
+ }
+
+ TokenStream(res_stream_lrc)
+ }
+ }
+ }
+}
+
+/// By-reference iterator over a [`TokenStream`].
+#[derive(Clone)]
+pub struct CursorRef<'t> {
+ stream: &'t TokenStream,
+ index: usize,
+}
+
+impl<'t> CursorRef<'t> {
+ fn new(stream: &'t TokenStream) -> Self {
+ CursorRef { stream, index: 0 }
+ }
+
+ pub fn look_ahead(&self, n: usize) -> Option<&TokenTree> {
+ self.stream.0.get(self.index + n)
+ }
+}
+
+impl<'t> Iterator for CursorRef<'t> {
+ type Item = &'t TokenTree;
+
+ fn next(&mut self) -> Option<&'t TokenTree> {
+ self.stream.0.get(self.index).map(|tree| {
+ self.index += 1;
+ tree
+ })
+ }
+}
+
+/// Owning by-value iterator over a [`TokenStream`].
+// FIXME: Many uses of this can be replaced with by-reference iterator to avoid clones.
+#[derive(Clone)]
+pub struct Cursor {
+ pub stream: TokenStream,
+ index: usize,
+}
+
+impl Iterator for Cursor {
+ type Item = TokenTree;
+
+ fn next(&mut self) -> Option<TokenTree> {
+ self.stream.0.get(self.index).map(|tree| {
+ self.index += 1;
+ tree.clone()
+ })
+ }
+}
+
+impl Cursor {
+ fn new(stream: TokenStream) -> Self {
+ Cursor { stream, index: 0 }
+ }
+
+ #[inline]
+ pub fn next_ref(&mut self) -> Option<&TokenTree> {
+ self.stream.0.get(self.index).map(|tree| {
+ self.index += 1;
+ tree
+ })
+ }
+
+ pub fn look_ahead(&self, n: usize) -> Option<&TokenTree> {
+ self.stream.0.get(self.index + n)
+ }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
+pub struct DelimSpan {
+ pub open: Span,
+ pub close: Span,
+}
+
+impl DelimSpan {
+ pub fn from_single(sp: Span) -> Self {
+ DelimSpan { open: sp, close: sp }
+ }
+
+ pub fn from_pair(open: Span, close: Span) -> Self {
+ DelimSpan { open, close }
+ }
+
+ pub fn dummy() -> Self {
+ Self::from_single(DUMMY_SP)
+ }
+
+ pub fn entire(self) -> Span {
+ self.open.with_hi(self.close.hi())
+ }
+}
diff --git a/compiler/rustc_ast/src/util/classify.rs b/compiler/rustc_ast/src/util/classify.rs
new file mode 100644
index 000000000..6ea3db6d3
--- /dev/null
+++ b/compiler/rustc_ast/src/util/classify.rs
@@ -0,0 +1,52 @@
+//! Routines the parser uses to classify AST nodes
+
+// Predicates on exprs and stmts that the pretty-printer and parser use
+
+use crate::ast;
+
+/// Does this expression require a semicolon to be treated
+/// as a statement? The negation of this: 'can this expression
+/// be used as a statement without a semicolon' -- is used
+/// as an early-bail-out in the parser so that, for instance,
+/// if true {...} else {...}
+/// |x| 5
+/// isn't parsed as (if true {...} else {...} | x) | 5
+pub fn expr_requires_semi_to_be_stmt(e: &ast::Expr) -> bool {
+ !matches!(
+ e.kind,
+ ast::ExprKind::If(..)
+ | ast::ExprKind::Match(..)
+ | ast::ExprKind::Block(..)
+ | ast::ExprKind::While(..)
+ | ast::ExprKind::Loop(..)
+ | ast::ExprKind::ForLoop(..)
+ | ast::ExprKind::TryBlock(..)
+ )
+}
+
+/// If an expression ends with `}`, returns the innermost expression ending in the `}`
+pub fn expr_trailing_brace(mut expr: &ast::Expr) -> Option<&ast::Expr> {
+ use ast::ExprKind::*;
+
+ loop {
+ match &expr.kind {
+ AddrOf(_, _, e)
+ | Assign(_, e, _)
+ | AssignOp(_, _, e)
+ | Binary(_, _, e)
+ | Box(e)
+ | Break(_, Some(e))
+ | Closure(.., e, _)
+ | Let(_, e, _)
+ | Range(_, Some(e), _)
+ | Ret(Some(e))
+ | Unary(_, e)
+ | Yield(Some(e)) => {
+ expr = e;
+ }
+ Async(..) | Block(..) | ForLoop(..) | If(..) | Loop(..) | Match(..) | Struct(..)
+ | TryBlock(..) | While(..) => break Some(expr),
+ _ => break None,
+ }
+ }
+}
diff --git a/compiler/rustc_ast/src/util/comments.rs b/compiler/rustc_ast/src/util/comments.rs
new file mode 100644
index 000000000..c96474ccb
--- /dev/null
+++ b/compiler/rustc_ast/src/util/comments.rs
@@ -0,0 +1,255 @@
+use crate::token::CommentKind;
+use rustc_span::source_map::SourceMap;
+use rustc_span::{BytePos, CharPos, FileName, Pos, Symbol};
+
+#[cfg(test)]
+mod tests;
+
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub enum CommentStyle {
+ /// No code on either side of each line of the comment
+ Isolated,
+ /// Code exists to the left of the comment
+ Trailing,
+ /// Code before /* foo */ and after the comment
+ Mixed,
+ /// Just a manual blank line "\n\n", for layout
+ BlankLine,
+}
+
+#[derive(Clone)]
+pub struct Comment {
+ pub style: CommentStyle,
+ pub lines: Vec<String>,
+ pub pos: BytePos,
+}
+
+/// A fast conservative estimate on whether the string can contain documentation links.
+/// A pair of square brackets `[]` must exist in the string, but we only search for the
+/// opening bracket because brackets always go in pairs in practice.
+#[inline]
+pub fn may_have_doc_links(s: &str) -> bool {
+ s.contains('[')
+}
+
+/// Makes a doc string more presentable to users.
+/// Used by rustdoc and perhaps other tools, but not by rustc.
+pub fn beautify_doc_string(data: Symbol, kind: CommentKind) -> Symbol {
+ fn get_vertical_trim(lines: &[&str]) -> Option<(usize, usize)> {
+ let mut i = 0;
+ let mut j = lines.len();
+ // first line of all-stars should be omitted
+ if !lines.is_empty() && lines[0].chars().all(|c| c == '*') {
+ i += 1;
+ }
+
+ // like the first, a last line of all stars should be omitted
+ if j > i && !lines[j - 1].is_empty() && lines[j - 1].chars().all(|c| c == '*') {
+ j -= 1;
+ }
+
+ if i != 0 || j != lines.len() { Some((i, j)) } else { None }
+ }
+
+ fn get_horizontal_trim<'a>(lines: &'a [&str], kind: CommentKind) -> Option<String> {
+ let mut i = usize::MAX;
+ let mut first = true;
+
+ // In case we have doc comments like `/**` or `/*!`, we want to remove stars if they are
+ // present. However, we first need to strip the empty lines so they don't get in the middle
+ // when we try to compute the "horizontal trim".
+ let lines = if kind == CommentKind::Block {
+ // Whatever happens, we skip the first line.
+ let mut i = lines
+ .get(0)
+ .map(|l| if l.trim_start().starts_with('*') { 0 } else { 1 })
+ .unwrap_or(0);
+ let mut j = lines.len();
+
+ while i < j && lines[i].trim().is_empty() {
+ i += 1;
+ }
+ while j > i && lines[j - 1].trim().is_empty() {
+ j -= 1;
+ }
+ &lines[i..j]
+ } else {
+ lines
+ };
+
+ for line in lines {
+ for (j, c) in line.chars().enumerate() {
+ if j > i || !"* \t".contains(c) {
+ return None;
+ }
+ if c == '*' {
+ if first {
+ i = j;
+ first = false;
+ } else if i != j {
+ return None;
+ }
+ break;
+ }
+ }
+ if i >= line.len() {
+ return None;
+ }
+ }
+ if lines.is_empty() { None } else { Some(lines[0][..i].into()) }
+ }
+
+ let data_s = data.as_str();
+ if data_s.contains('\n') {
+ let mut lines = data_s.lines().collect::<Vec<&str>>();
+ let mut changes = false;
+ let lines = if let Some((i, j)) = get_vertical_trim(&lines) {
+ changes = true;
+ // remove whitespace-only lines from the start/end of lines
+ &mut lines[i..j]
+ } else {
+ &mut lines
+ };
+ if let Some(horizontal) = get_horizontal_trim(&lines, kind) {
+ changes = true;
+ // remove a "[ \t]*\*" block from each line, if possible
+ for line in lines.iter_mut() {
+ if let Some(tmp) = line.strip_prefix(&horizontal) {
+ *line = tmp;
+ if kind == CommentKind::Block
+ && (*line == "*" || line.starts_with("* ") || line.starts_with("**"))
+ {
+ *line = &line[1..];
+ }
+ }
+ }
+ }
+ if changes {
+ return Symbol::intern(&lines.join("\n"));
+ }
+ }
+ data
+}
+
+/// Returns `None` if the first `col` chars of `s` contain a non-whitespace char.
+/// Otherwise returns `Some(k)` where `k` is first char offset after that leading
+/// whitespace. Note that `k` may be outside bounds of `s`.
+fn all_whitespace(s: &str, col: CharPos) -> Option<usize> {
+ let mut idx = 0;
+ for (i, ch) in s.char_indices().take(col.to_usize()) {
+ if !ch.is_whitespace() {
+ return None;
+ }
+ idx = i + ch.len_utf8();
+ }
+ Some(idx)
+}
+
+fn trim_whitespace_prefix(s: &str, col: CharPos) -> &str {
+ let len = s.len();
+ match all_whitespace(&s, col) {
+ Some(col) => {
+ if col < len {
+ &s[col..]
+ } else {
+ ""
+ }
+ }
+ None => s,
+ }
+}
+
+fn split_block_comment_into_lines(text: &str, col: CharPos) -> Vec<String> {
+ let mut res: Vec<String> = vec![];
+ let mut lines = text.lines();
+ // just push the first line
+ res.extend(lines.next().map(|it| it.to_string()));
+ // for other lines, strip common whitespace prefix
+ for line in lines {
+ res.push(trim_whitespace_prefix(line, col).to_string())
+ }
+ res
+}
+
+// it appears this function is called only from pprust... that's
+// probably not a good thing.
+pub fn gather_comments(sm: &SourceMap, path: FileName, src: String) -> Vec<Comment> {
+ let sm = SourceMap::new(sm.path_mapping().clone());
+ let source_file = sm.new_source_file(path, src);
+ let text = (*source_file.src.as_ref().unwrap()).clone();
+
+ let text: &str = text.as_str();
+ let start_bpos = source_file.start_pos;
+ let mut pos = 0;
+ let mut comments: Vec<Comment> = Vec::new();
+ let mut code_to_the_left = false;
+
+ if let Some(shebang_len) = rustc_lexer::strip_shebang(text) {
+ comments.push(Comment {
+ style: CommentStyle::Isolated,
+ lines: vec![text[..shebang_len].to_string()],
+ pos: start_bpos,
+ });
+ pos += shebang_len;
+ }
+
+ for token in rustc_lexer::tokenize(&text[pos..]) {
+ let token_text = &text[pos..pos + token.len as usize];
+ match token.kind {
+ rustc_lexer::TokenKind::Whitespace => {
+ if let Some(mut idx) = token_text.find('\n') {
+ code_to_the_left = false;
+ while let Some(next_newline) = &token_text[idx + 1..].find('\n') {
+ idx += 1 + next_newline;
+ comments.push(Comment {
+ style: CommentStyle::BlankLine,
+ lines: vec![],
+ pos: start_bpos + BytePos((pos + idx) as u32),
+ });
+ }
+ }
+ }
+ rustc_lexer::TokenKind::BlockComment { doc_style, .. } => {
+ if doc_style.is_none() {
+ let code_to_the_right = !matches!(
+ text[pos + token.len as usize..].chars().next(),
+ Some('\r' | '\n')
+ );
+ let style = match (code_to_the_left, code_to_the_right) {
+ (_, true) => CommentStyle::Mixed,
+ (false, false) => CommentStyle::Isolated,
+ (true, false) => CommentStyle::Trailing,
+ };
+
+ // Count the number of chars since the start of the line by rescanning.
+ let pos_in_file = start_bpos + BytePos(pos as u32);
+ let line_begin_in_file = source_file.line_begin_pos(pos_in_file);
+ let line_begin_pos = (line_begin_in_file - start_bpos).to_usize();
+ let col = CharPos(text[line_begin_pos..pos].chars().count());
+
+ let lines = split_block_comment_into_lines(token_text, col);
+ comments.push(Comment { style, lines, pos: pos_in_file })
+ }
+ }
+ rustc_lexer::TokenKind::LineComment { doc_style } => {
+ if doc_style.is_none() {
+ comments.push(Comment {
+ style: if code_to_the_left {
+ CommentStyle::Trailing
+ } else {
+ CommentStyle::Isolated
+ },
+ lines: vec![token_text.to_string()],
+ pos: start_bpos + BytePos(pos as u32),
+ })
+ }
+ }
+ _ => {
+ code_to_the_left = true;
+ }
+ }
+ pos += token.len as usize;
+ }
+
+ comments
+}
diff --git a/compiler/rustc_ast/src/util/comments/tests.rs b/compiler/rustc_ast/src/util/comments/tests.rs
new file mode 100644
index 000000000..11d50603a
--- /dev/null
+++ b/compiler/rustc_ast/src/util/comments/tests.rs
@@ -0,0 +1,61 @@
+use super::*;
+use rustc_span::create_default_session_globals_then;
+
+#[test]
+fn test_block_doc_comment_1() {
+ create_default_session_globals_then(|| {
+ let comment = "\n * Test \n ** Test\n * Test\n";
+ let stripped = beautify_doc_string(Symbol::intern(comment), CommentKind::Block);
+ assert_eq!(stripped.as_str(), " Test \n* Test\n Test");
+ })
+}
+
+#[test]
+fn test_block_doc_comment_2() {
+ create_default_session_globals_then(|| {
+ let comment = "\n * Test\n * Test\n";
+ let stripped = beautify_doc_string(Symbol::intern(comment), CommentKind::Block);
+ assert_eq!(stripped.as_str(), " Test\n Test");
+ })
+}
+
+#[test]
+fn test_block_doc_comment_3() {
+ create_default_session_globals_then(|| {
+ let comment = "\n let a: *i32;\n *a = 5;\n";
+ let stripped = beautify_doc_string(Symbol::intern(comment), CommentKind::Block);
+ assert_eq!(stripped.as_str(), "let a: *i32;\n*a = 5;");
+ })
+}
+
+#[test]
+fn test_line_doc_comment() {
+ create_default_session_globals_then(|| {
+ let stripped = beautify_doc_string(Symbol::intern(" test"), CommentKind::Line);
+ assert_eq!(stripped.as_str(), " test");
+ let stripped = beautify_doc_string(Symbol::intern("! test"), CommentKind::Line);
+ assert_eq!(stripped.as_str(), "! test");
+ let stripped = beautify_doc_string(Symbol::intern("test"), CommentKind::Line);
+ assert_eq!(stripped.as_str(), "test");
+ let stripped = beautify_doc_string(Symbol::intern("!test"), CommentKind::Line);
+ assert_eq!(stripped.as_str(), "!test");
+ })
+}
+
+#[test]
+fn test_doc_blocks() {
+ create_default_session_globals_then(|| {
+ let stripped =
+ beautify_doc_string(Symbol::intern(" # Returns\n *\n "), CommentKind::Block);
+ assert_eq!(stripped.as_str(), " # Returns\n\n");
+
+ let stripped = beautify_doc_string(
+ Symbol::intern("\n * # Returns\n *\n "),
+ CommentKind::Block,
+ );
+ assert_eq!(stripped.as_str(), " # Returns\n\n");
+
+ let stripped = beautify_doc_string(Symbol::intern("\n * a\n "), CommentKind::Block);
+ assert_eq!(stripped.as_str(), " a\n");
+ })
+}
diff --git a/compiler/rustc_ast/src/util/literal.rs b/compiler/rustc_ast/src/util/literal.rs
new file mode 100644
index 000000000..9c18f55c0
--- /dev/null
+++ b/compiler/rustc_ast/src/util/literal.rs
@@ -0,0 +1,336 @@
+//! Code related to parsing literals.
+
+use crate::ast::{self, Lit, LitKind};
+use crate::token::{self, Token};
+
+use rustc_lexer::unescape::{unescape_byte, unescape_char};
+use rustc_lexer::unescape::{unescape_byte_literal, unescape_literal, Mode};
+use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::Span;
+
+use std::ascii;
+use tracing::debug;
+
+pub enum LitError {
+ NotLiteral,
+ LexerError,
+ InvalidSuffix,
+ InvalidIntSuffix,
+ InvalidFloatSuffix,
+ NonDecimalFloat(u32),
+ IntTooLarge,
+}
+
+impl LitKind {
+ /// Converts literal token into a semantic literal.
+ pub fn from_lit_token(lit: token::Lit) -> Result<LitKind, LitError> {
+ let token::Lit { kind, symbol, suffix } = lit;
+ if suffix.is_some() && !kind.may_have_suffix() {
+ return Err(LitError::InvalidSuffix);
+ }
+
+ Ok(match kind {
+ token::Bool => {
+ assert!(symbol.is_bool_lit());
+ LitKind::Bool(symbol == kw::True)
+ }
+ token::Byte => {
+ return unescape_byte(symbol.as_str())
+ .map(LitKind::Byte)
+ .map_err(|_| LitError::LexerError);
+ }
+ token::Char => {
+ return unescape_char(symbol.as_str())
+ .map(LitKind::Char)
+ .map_err(|_| LitError::LexerError);
+ }
+
+ // There are some valid suffixes for integer and float literals,
+ // so all the handling is done internally.
+ token::Integer => return integer_lit(symbol, suffix),
+ token::Float => return float_lit(symbol, suffix),
+
+ token::Str => {
+ // If there are no characters requiring special treatment we can
+ // reuse the symbol from the token. Otherwise, we must generate a
+ // new symbol because the string in the LitKind is different to the
+ // string in the token.
+ let s = symbol.as_str();
+ let symbol = if s.contains(&['\\', '\r']) {
+ let mut buf = String::with_capacity(s.len());
+ let mut error = Ok(());
+ // Force-inlining here is aggressive but the closure is
+ // called on every char in the string, so it can be
+ // hot in programs with many long strings.
+ unescape_literal(
+ &s,
+ Mode::Str,
+ &mut #[inline(always)]
+ |_, unescaped_char| match unescaped_char {
+ Ok(c) => buf.push(c),
+ Err(err) => {
+ if err.is_fatal() {
+ error = Err(LitError::LexerError);
+ }
+ }
+ },
+ );
+ error?;
+ Symbol::intern(&buf)
+ } else {
+ symbol
+ };
+ LitKind::Str(symbol, ast::StrStyle::Cooked)
+ }
+ token::StrRaw(n) => {
+ // Ditto.
+ let s = symbol.as_str();
+ let symbol =
+ if s.contains('\r') {
+ let mut buf = String::with_capacity(s.len());
+ let mut error = Ok(());
+ unescape_literal(&s, Mode::RawStr, &mut |_, unescaped_char| {
+ match unescaped_char {
+ Ok(c) => buf.push(c),
+ Err(err) => {
+ if err.is_fatal() {
+ error = Err(LitError::LexerError);
+ }
+ }
+ }
+ });
+ error?;
+ Symbol::intern(&buf)
+ } else {
+ symbol
+ };
+ LitKind::Str(symbol, ast::StrStyle::Raw(n))
+ }
+ token::ByteStr => {
+ let s = symbol.as_str();
+ let mut buf = Vec::with_capacity(s.len());
+ let mut error = Ok(());
+ unescape_byte_literal(&s, Mode::ByteStr, &mut |_, unescaped_byte| {
+ match unescaped_byte {
+ Ok(c) => buf.push(c),
+ Err(err) => {
+ if err.is_fatal() {
+ error = Err(LitError::LexerError);
+ }
+ }
+ }
+ });
+ error?;
+ LitKind::ByteStr(buf.into())
+ }
+ token::ByteStrRaw(_) => {
+ let s = symbol.as_str();
+ let bytes = if s.contains('\r') {
+ let mut buf = Vec::with_capacity(s.len());
+ let mut error = Ok(());
+ unescape_byte_literal(&s, Mode::RawByteStr, &mut |_, unescaped_byte| {
+ match unescaped_byte {
+ Ok(c) => buf.push(c),
+ Err(err) => {
+ if err.is_fatal() {
+ error = Err(LitError::LexerError);
+ }
+ }
+ }
+ });
+ error?;
+ buf
+ } else {
+ symbol.to_string().into_bytes()
+ };
+
+ LitKind::ByteStr(bytes.into())
+ }
+ token::Err => LitKind::Err(symbol),
+ })
+ }
+
+ /// Attempts to recover a token from semantic literal.
+ /// This function is used when the original token doesn't exist (e.g. the literal is created
+ /// by an AST-based macro) or unavailable (e.g. from HIR pretty-printing).
+ pub fn to_lit_token(&self) -> token::Lit {
+ let (kind, symbol, suffix) = match *self {
+ LitKind::Str(symbol, ast::StrStyle::Cooked) => {
+ // Don't re-intern unless the escaped string is different.
+ let s = symbol.as_str();
+ let escaped = s.escape_default().to_string();
+ let symbol = if s == escaped { symbol } else { Symbol::intern(&escaped) };
+ (token::Str, symbol, None)
+ }
+ LitKind::Str(symbol, ast::StrStyle::Raw(n)) => (token::StrRaw(n), symbol, None),
+ LitKind::ByteStr(ref bytes) => {
+ let string = bytes
+ .iter()
+ .cloned()
+ .flat_map(ascii::escape_default)
+ .map(Into::<char>::into)
+ .collect::<String>();
+ (token::ByteStr, Symbol::intern(&string), None)
+ }
+ LitKind::Byte(byte) => {
+ let string: String = ascii::escape_default(byte).map(Into::<char>::into).collect();
+ (token::Byte, Symbol::intern(&string), None)
+ }
+ LitKind::Char(ch) => {
+ let string: String = ch.escape_default().map(Into::<char>::into).collect();
+ (token::Char, Symbol::intern(&string), None)
+ }
+ LitKind::Int(n, ty) => {
+ let suffix = match ty {
+ ast::LitIntType::Unsigned(ty) => Some(ty.name()),
+ ast::LitIntType::Signed(ty) => Some(ty.name()),
+ ast::LitIntType::Unsuffixed => None,
+ };
+ (token::Integer, sym::integer(n), suffix)
+ }
+ LitKind::Float(symbol, ty) => {
+ let suffix = match ty {
+ ast::LitFloatType::Suffixed(ty) => Some(ty.name()),
+ ast::LitFloatType::Unsuffixed => None,
+ };
+ (token::Float, symbol, suffix)
+ }
+ LitKind::Bool(value) => {
+ let symbol = if value { kw::True } else { kw::False };
+ (token::Bool, symbol, None)
+ }
+ LitKind::Err(symbol) => (token::Err, symbol, None),
+ };
+
+ token::Lit::new(kind, symbol, suffix)
+ }
+}
+
+impl Lit {
+ /// Converts literal token into an AST literal.
+ pub fn from_lit_token(token: token::Lit, span: Span) -> Result<Lit, LitError> {
+ Ok(Lit { token, kind: LitKind::from_lit_token(token)?, span })
+ }
+
+ /// Converts arbitrary token into an AST literal.
+ ///
+ /// Keep this in sync with `Token::can_begin_literal_or_bool` excluding unary negation.
+ pub fn from_token(token: &Token) -> Result<Lit, LitError> {
+ let lit = match token.uninterpolate().kind {
+ token::Ident(name, false) if name.is_bool_lit() => {
+ token::Lit::new(token::Bool, name, None)
+ }
+ token::Literal(lit) => lit,
+ token::Interpolated(ref nt) => {
+ if let token::NtExpr(expr) | token::NtLiteral(expr) = &**nt
+ && let ast::ExprKind::Lit(lit) = &expr.kind
+ {
+ return Ok(lit.clone());
+ }
+ return Err(LitError::NotLiteral);
+ }
+ _ => return Err(LitError::NotLiteral),
+ };
+
+ Lit::from_lit_token(lit, token.span)
+ }
+
+ /// Attempts to recover an AST literal from semantic literal.
+ /// This function is used when the original token doesn't exist (e.g. the literal is created
+ /// by an AST-based macro) or unavailable (e.g. from HIR pretty-printing).
+ pub fn from_lit_kind(kind: LitKind, span: Span) -> Lit {
+ Lit { token: kind.to_lit_token(), kind, span }
+ }
+
+ /// Losslessly convert an AST literal into a token.
+ pub fn to_token(&self) -> Token {
+ let kind = match self.token.kind {
+ token::Bool => token::Ident(self.token.symbol, false),
+ _ => token::Literal(self.token),
+ };
+ Token::new(kind, self.span)
+ }
+}
+
+fn strip_underscores(symbol: Symbol) -> Symbol {
+ // Do not allocate a new string unless necessary.
+ let s = symbol.as_str();
+ if s.contains('_') {
+ let mut s = s.to_string();
+ s.retain(|c| c != '_');
+ return Symbol::intern(&s);
+ }
+ symbol
+}
+
+fn filtered_float_lit(
+ symbol: Symbol,
+ suffix: Option<Symbol>,
+ base: u32,
+) -> Result<LitKind, LitError> {
+ debug!("filtered_float_lit: {:?}, {:?}, {:?}", symbol, suffix, base);
+ if base != 10 {
+ return Err(LitError::NonDecimalFloat(base));
+ }
+ Ok(match suffix {
+ Some(suf) => LitKind::Float(
+ symbol,
+ ast::LitFloatType::Suffixed(match suf {
+ sym::f32 => ast::FloatTy::F32,
+ sym::f64 => ast::FloatTy::F64,
+ _ => return Err(LitError::InvalidFloatSuffix),
+ }),
+ ),
+ None => LitKind::Float(symbol, ast::LitFloatType::Unsuffixed),
+ })
+}
+
+fn float_lit(symbol: Symbol, suffix: Option<Symbol>) -> Result<LitKind, LitError> {
+ debug!("float_lit: {:?}, {:?}", symbol, suffix);
+ filtered_float_lit(strip_underscores(symbol), suffix, 10)
+}
+
+fn integer_lit(symbol: Symbol, suffix: Option<Symbol>) -> Result<LitKind, LitError> {
+ debug!("integer_lit: {:?}, {:?}", symbol, suffix);
+ let symbol = strip_underscores(symbol);
+ let s = symbol.as_str();
+
+ let base = match s.as_bytes() {
+ [b'0', b'x', ..] => 16,
+ [b'0', b'o', ..] => 8,
+ [b'0', b'b', ..] => 2,
+ _ => 10,
+ };
+
+ let ty = match suffix {
+ Some(suf) => match suf {
+ sym::isize => ast::LitIntType::Signed(ast::IntTy::Isize),
+ sym::i8 => ast::LitIntType::Signed(ast::IntTy::I8),
+ sym::i16 => ast::LitIntType::Signed(ast::IntTy::I16),
+ sym::i32 => ast::LitIntType::Signed(ast::IntTy::I32),
+ sym::i64 => ast::LitIntType::Signed(ast::IntTy::I64),
+ sym::i128 => ast::LitIntType::Signed(ast::IntTy::I128),
+ sym::usize => ast::LitIntType::Unsigned(ast::UintTy::Usize),
+ sym::u8 => ast::LitIntType::Unsigned(ast::UintTy::U8),
+ sym::u16 => ast::LitIntType::Unsigned(ast::UintTy::U16),
+ sym::u32 => ast::LitIntType::Unsigned(ast::UintTy::U32),
+ sym::u64 => ast::LitIntType::Unsigned(ast::UintTy::U64),
+ sym::u128 => ast::LitIntType::Unsigned(ast::UintTy::U128),
+ // `1f64` and `2f32` etc. are valid float literals, and
+ // `fxxx` looks more like an invalid float literal than invalid integer literal.
+ _ if suf.as_str().starts_with('f') => return filtered_float_lit(symbol, suffix, base),
+ _ => return Err(LitError::InvalidIntSuffix),
+ },
+ _ => ast::LitIntType::Unsuffixed,
+ };
+
+ let s = &s[if base != 10 { 2 } else { 0 }..];
+ u128::from_str_radix(s, base).map(|i| LitKind::Int(i, ty)).map_err(|_| {
+ // Small bases are lexed as if they were base 10, e.g, the string
+ // might be `0b10201`. This will cause the conversion above to fail,
+ // but these kinds of errors are already reported by the lexer.
+ let from_lexer =
+ base < 10 && s.chars().any(|c| c.to_digit(10).map_or(false, |d| d >= base));
+ if from_lexer { LitError::LexerError } else { LitError::IntTooLarge }
+ })
+}
diff --git a/compiler/rustc_ast/src/util/parser.rs b/compiler/rustc_ast/src/util/parser.rs
new file mode 100644
index 000000000..74b7fe9e2
--- /dev/null
+++ b/compiler/rustc_ast/src/util/parser.rs
@@ -0,0 +1,406 @@
+use crate::ast::{self, BinOpKind};
+use crate::token::{self, BinOpToken, Token};
+use rustc_span::symbol::kw;
+
+/// Associative operator with precedence.
+///
+/// This is the enum which specifies operator precedence and fixity to the parser.
+#[derive(Copy, Clone, PartialEq, Debug)]
+pub enum AssocOp {
+ /// `+`
+ Add,
+ /// `-`
+ Subtract,
+ /// `*`
+ Multiply,
+ /// `/`
+ Divide,
+ /// `%`
+ Modulus,
+ /// `&&`
+ LAnd,
+ /// `||`
+ LOr,
+ /// `^`
+ BitXor,
+ /// `&`
+ BitAnd,
+ /// `|`
+ BitOr,
+ /// `<<`
+ ShiftLeft,
+ /// `>>`
+ ShiftRight,
+ /// `==`
+ Equal,
+ /// `<`
+ Less,
+ /// `<=`
+ LessEqual,
+ /// `!=`
+ NotEqual,
+ /// `>`
+ Greater,
+ /// `>=`
+ GreaterEqual,
+ /// `=`
+ Assign,
+ /// `?=` where ? is one of the BinOpToken
+ AssignOp(BinOpToken),
+ /// `as`
+ As,
+ /// `..` range
+ DotDot,
+ /// `..=` range
+ DotDotEq,
+ /// `:`
+ Colon,
+}
+
+#[derive(PartialEq, Debug)]
+pub enum Fixity {
+ /// The operator is left-associative
+ Left,
+ /// The operator is right-associative
+ Right,
+ /// The operator is not associative
+ None,
+}
+
+impl AssocOp {
+ /// Creates a new AssocOP from a token
+ pub fn from_token(t: &Token) -> Option<AssocOp> {
+ use AssocOp::*;
+ match t.kind {
+ token::BinOpEq(k) => Some(AssignOp(k)),
+ token::Eq => Some(Assign),
+ token::BinOp(BinOpToken::Star) => Some(Multiply),
+ token::BinOp(BinOpToken::Slash) => Some(Divide),
+ token::BinOp(BinOpToken::Percent) => Some(Modulus),
+ token::BinOp(BinOpToken::Plus) => Some(Add),
+ token::BinOp(BinOpToken::Minus) => Some(Subtract),
+ token::BinOp(BinOpToken::Shl) => Some(ShiftLeft),
+ token::BinOp(BinOpToken::Shr) => Some(ShiftRight),
+ token::BinOp(BinOpToken::And) => Some(BitAnd),
+ token::BinOp(BinOpToken::Caret) => Some(BitXor),
+ token::BinOp(BinOpToken::Or) => Some(BitOr),
+ token::Lt => Some(Less),
+ token::Le => Some(LessEqual),
+ token::Ge => Some(GreaterEqual),
+ token::Gt => Some(Greater),
+ token::EqEq => Some(Equal),
+ token::Ne => Some(NotEqual),
+ token::AndAnd => Some(LAnd),
+ token::OrOr => Some(LOr),
+ token::DotDot => Some(DotDot),
+ token::DotDotEq => Some(DotDotEq),
+ // DotDotDot is no longer supported, but we need some way to display the error
+ token::DotDotDot => Some(DotDotEq),
+ token::Colon => Some(Colon),
+ // `<-` should probably be `< -`
+ token::LArrow => Some(Less),
+ _ if t.is_keyword(kw::As) => Some(As),
+ _ => None,
+ }
+ }
+
+ /// Creates a new AssocOp from ast::BinOpKind.
+ pub fn from_ast_binop(op: BinOpKind) -> Self {
+ use AssocOp::*;
+ match op {
+ BinOpKind::Lt => Less,
+ BinOpKind::Gt => Greater,
+ BinOpKind::Le => LessEqual,
+ BinOpKind::Ge => GreaterEqual,
+ BinOpKind::Eq => Equal,
+ BinOpKind::Ne => NotEqual,
+ BinOpKind::Mul => Multiply,
+ BinOpKind::Div => Divide,
+ BinOpKind::Rem => Modulus,
+ BinOpKind::Add => Add,
+ BinOpKind::Sub => Subtract,
+ BinOpKind::Shl => ShiftLeft,
+ BinOpKind::Shr => ShiftRight,
+ BinOpKind::BitAnd => BitAnd,
+ BinOpKind::BitXor => BitXor,
+ BinOpKind::BitOr => BitOr,
+ BinOpKind::And => LAnd,
+ BinOpKind::Or => LOr,
+ }
+ }
+
+ /// Gets the precedence of this operator
+ pub fn precedence(&self) -> usize {
+ use AssocOp::*;
+ match *self {
+ As | Colon => 14,
+ Multiply | Divide | Modulus => 13,
+ Add | Subtract => 12,
+ ShiftLeft | ShiftRight => 11,
+ BitAnd => 10,
+ BitXor => 9,
+ BitOr => 8,
+ Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual => 7,
+ LAnd => 6,
+ LOr => 5,
+ DotDot | DotDotEq => 4,
+ Assign | AssignOp(_) => 2,
+ }
+ }
+
+ /// Gets the fixity of this operator
+ pub fn fixity(&self) -> Fixity {
+ use AssocOp::*;
+ // NOTE: it is a bug to have an operators that has same precedence but different fixities!
+ match *self {
+ Assign | AssignOp(_) => Fixity::Right,
+ As | Multiply | Divide | Modulus | Add | Subtract | ShiftLeft | ShiftRight | BitAnd
+ | BitXor | BitOr | Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual
+ | LAnd | LOr | Colon => Fixity::Left,
+ DotDot | DotDotEq => Fixity::None,
+ }
+ }
+
+ pub fn is_comparison(&self) -> bool {
+ use AssocOp::*;
+ match *self {
+ Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual => true,
+ Assign | AssignOp(_) | As | Multiply | Divide | Modulus | Add | Subtract
+ | ShiftLeft | ShiftRight | BitAnd | BitXor | BitOr | LAnd | LOr | DotDot | DotDotEq
+ | Colon => false,
+ }
+ }
+
+ pub fn is_assign_like(&self) -> bool {
+ use AssocOp::*;
+ match *self {
+ Assign | AssignOp(_) => true,
+ Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual | As | Multiply
+ | Divide | Modulus | Add | Subtract | ShiftLeft | ShiftRight | BitAnd | BitXor
+ | BitOr | LAnd | LOr | DotDot | DotDotEq | Colon => false,
+ }
+ }
+
+ pub fn to_ast_binop(&self) -> Option<BinOpKind> {
+ use AssocOp::*;
+ match *self {
+ Less => Some(BinOpKind::Lt),
+ Greater => Some(BinOpKind::Gt),
+ LessEqual => Some(BinOpKind::Le),
+ GreaterEqual => Some(BinOpKind::Ge),
+ Equal => Some(BinOpKind::Eq),
+ NotEqual => Some(BinOpKind::Ne),
+ Multiply => Some(BinOpKind::Mul),
+ Divide => Some(BinOpKind::Div),
+ Modulus => Some(BinOpKind::Rem),
+ Add => Some(BinOpKind::Add),
+ Subtract => Some(BinOpKind::Sub),
+ ShiftLeft => Some(BinOpKind::Shl),
+ ShiftRight => Some(BinOpKind::Shr),
+ BitAnd => Some(BinOpKind::BitAnd),
+ BitXor => Some(BinOpKind::BitXor),
+ BitOr => Some(BinOpKind::BitOr),
+ LAnd => Some(BinOpKind::And),
+ LOr => Some(BinOpKind::Or),
+ Assign | AssignOp(_) | As | DotDot | DotDotEq | Colon => None,
+ }
+ }
+
+ /// This operator could be used to follow a block unambiguously.
+ ///
+ /// This is used for error recovery at the moment, providing a suggestion to wrap blocks with
+ /// parentheses while having a high degree of confidence on the correctness of the suggestion.
+ pub fn can_continue_expr_unambiguously(&self) -> bool {
+ use AssocOp::*;
+ matches!(
+ self,
+ BitXor | // `{ 42 } ^ 3`
+ Assign | // `{ 42 } = { 42 }`
+ Divide | // `{ 42 } / 42`
+ Modulus | // `{ 42 } % 2`
+ ShiftRight | // `{ 42 } >> 2`
+ LessEqual | // `{ 42 } <= 3`
+ Greater | // `{ 42 } > 3`
+ GreaterEqual | // `{ 42 } >= 3`
+ AssignOp(_) | // `{ 42 } +=`
+ As | // `{ 42 } as usize`
+ // Equal | // `{ 42 } == { 42 }` Accepting these here would regress incorrect
+ // NotEqual | // `{ 42 } != { 42 } struct literals parser recovery.
+ Colon, // `{ 42 }: usize`
+ )
+ }
+}
+
+pub const PREC_CLOSURE: i8 = -40;
+pub const PREC_JUMP: i8 = -30;
+pub const PREC_RANGE: i8 = -10;
+// The range 2..=14 is reserved for AssocOp binary operator precedences.
+pub const PREC_PREFIX: i8 = 50;
+pub const PREC_POSTFIX: i8 = 60;
+pub const PREC_PAREN: i8 = 99;
+pub const PREC_FORCE_PAREN: i8 = 100;
+
+#[derive(Debug, Clone, Copy)]
+pub enum ExprPrecedence {
+ Closure,
+ Break,
+ Continue,
+ Ret,
+ Yield,
+ Yeet,
+
+ Range,
+
+ Binary(BinOpKind),
+
+ Cast,
+ Type,
+
+ Assign,
+ AssignOp,
+
+ Box,
+ AddrOf,
+ Let,
+ Unary,
+
+ Call,
+ MethodCall,
+ Field,
+ Index,
+ Try,
+ InlineAsm,
+ Mac,
+
+ Array,
+ Repeat,
+ Tup,
+ Lit,
+ Path,
+ Paren,
+ If,
+ While,
+ ForLoop,
+ Loop,
+ Match,
+ ConstBlock,
+ Block,
+ TryBlock,
+ Struct,
+ Async,
+ Await,
+ Err,
+}
+
+impl ExprPrecedence {
+ pub fn order(self) -> i8 {
+ match self {
+ ExprPrecedence::Closure => PREC_CLOSURE,
+
+ ExprPrecedence::Break |
+ ExprPrecedence::Continue |
+ ExprPrecedence::Ret |
+ ExprPrecedence::Yield |
+ ExprPrecedence::Yeet => PREC_JUMP,
+
+ // `Range` claims to have higher precedence than `Assign`, but `x .. x = x` fails to
+ // parse, instead of parsing as `(x .. x) = x`. Giving `Range` a lower precedence
+ // ensures that `pprust` will add parentheses in the right places to get the desired
+ // parse.
+ ExprPrecedence::Range => PREC_RANGE,
+
+ // Binop-like expr kinds, handled by `AssocOp`.
+ ExprPrecedence::Binary(op) => AssocOp::from_ast_binop(op).precedence() as i8,
+ ExprPrecedence::Cast => AssocOp::As.precedence() as i8,
+ ExprPrecedence::Type => AssocOp::Colon.precedence() as i8,
+
+ ExprPrecedence::Assign |
+ ExprPrecedence::AssignOp => AssocOp::Assign.precedence() as i8,
+
+ // Unary, prefix
+ ExprPrecedence::Box |
+ ExprPrecedence::AddrOf |
+ // Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
+ // However, this is not exactly right. When `let _ = a` is the LHS of a binop we
+ // need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
+ // but we need to print `(let _ = a) < b` as-is with parens.
+ ExprPrecedence::Let |
+ ExprPrecedence::Unary => PREC_PREFIX,
+
+ // Unary, postfix
+ ExprPrecedence::Await |
+ ExprPrecedence::Call |
+ ExprPrecedence::MethodCall |
+ ExprPrecedence::Field |
+ ExprPrecedence::Index |
+ ExprPrecedence::Try |
+ ExprPrecedence::InlineAsm |
+ ExprPrecedence::Mac => PREC_POSTFIX,
+
+ // Never need parens
+ ExprPrecedence::Array |
+ ExprPrecedence::Repeat |
+ ExprPrecedence::Tup |
+ ExprPrecedence::Lit |
+ ExprPrecedence::Path |
+ ExprPrecedence::Paren |
+ ExprPrecedence::If |
+ ExprPrecedence::While |
+ ExprPrecedence::ForLoop |
+ ExprPrecedence::Loop |
+ ExprPrecedence::Match |
+ ExprPrecedence::ConstBlock |
+ ExprPrecedence::Block |
+ ExprPrecedence::TryBlock |
+ ExprPrecedence::Async |
+ ExprPrecedence::Struct |
+ ExprPrecedence::Err => PREC_PAREN,
+ }
+ }
+}
+
+/// In `let p = e`, operators with precedence `<=` this one requires parentheses in `e`.
+pub fn prec_let_scrutinee_needs_par() -> usize {
+ AssocOp::LAnd.precedence()
+}
+
+/// Suppose we have `let _ = e` and the `order` of `e`.
+/// Is the `order` such that `e` in `let _ = e` needs parentheses when it is on the RHS?
+///
+/// Conversely, suppose that we have `(let _ = a) OP b` and `order` is that of `OP`.
+/// Can we print this as `let _ = a OP b`?
+pub fn needs_par_as_let_scrutinee(order: i8) -> bool {
+ order <= prec_let_scrutinee_needs_par() as i8
+}
+
+/// Expressions that syntactically contain an "exterior" struct literal i.e., not surrounded by any
+/// parens or other delimiters, e.g., `X { y: 1 }`, `X { y: 1 }.method()`, `foo == X { y: 1 }` and
+/// `X { y: 1 } == foo` all do, but `(X { y: 1 }) == foo` does not.
+pub fn contains_exterior_struct_lit(value: &ast::Expr) -> bool {
+ match value.kind {
+ ast::ExprKind::Struct(..) => true,
+
+ ast::ExprKind::Assign(ref lhs, ref rhs, _)
+ | ast::ExprKind::AssignOp(_, ref lhs, ref rhs)
+ | ast::ExprKind::Binary(_, ref lhs, ref rhs) => {
+ // X { y: 1 } + X { y: 2 }
+ contains_exterior_struct_lit(&lhs) || contains_exterior_struct_lit(&rhs)
+ }
+ ast::ExprKind::Await(ref x)
+ | ast::ExprKind::Unary(_, ref x)
+ | ast::ExprKind::Cast(ref x, _)
+ | ast::ExprKind::Type(ref x, _)
+ | ast::ExprKind::Field(ref x, _)
+ | ast::ExprKind::Index(ref x, _) => {
+ // &X { y: 1 }, X { y: 1 }.y
+ contains_exterior_struct_lit(&x)
+ }
+
+ ast::ExprKind::MethodCall(.., ref exprs, _) => {
+ // X { y: 1 }.bar(...)
+ contains_exterior_struct_lit(&exprs[0])
+ }
+
+ _ => false,
+ }
+}
diff --git a/compiler/rustc_ast/src/util/unicode.rs b/compiler/rustc_ast/src/util/unicode.rs
new file mode 100644
index 000000000..f009f7b30
--- /dev/null
+++ b/compiler/rustc_ast/src/util/unicode.rs
@@ -0,0 +1,35 @@
+pub const TEXT_FLOW_CONTROL_CHARS: &[char] = &[
+ '\u{202A}', '\u{202B}', '\u{202D}', '\u{202E}', '\u{2066}', '\u{2067}', '\u{2068}', '\u{202C}',
+ '\u{2069}',
+];
+
+#[inline]
+pub fn contains_text_flow_control_chars(s: &str) -> bool {
+ // Char - UTF-8
+ // U+202A - E2 80 AA
+ // U+202B - E2 80 AB
+ // U+202C - E2 80 AC
+ // U+202D - E2 80 AD
+ // U+202E - E2 80 AE
+ // U+2066 - E2 81 A6
+ // U+2067 - E2 81 A7
+ // U+2068 - E2 81 A8
+ // U+2069 - E2 81 A9
+ let mut bytes = s.as_bytes();
+ loop {
+ match core::slice::memchr::memchr(0xE2, &bytes) {
+ Some(idx) => {
+ // bytes are valid UTF-8 -> E2 must be followed by two bytes
+ let ch = &bytes[idx..idx + 3];
+ match ch {
+ [_, 0x80, 0xAA..=0xAE] | [_, 0x81, 0xA6..=0xA9] => break true,
+ _ => {}
+ }
+ bytes = &bytes[idx + 3..];
+ }
+ None => {
+ break false;
+ }
+ }
+ }
+}
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
new file mode 100644
index 000000000..d9594b323
--- /dev/null
+++ b/compiler/rustc_ast/src/visit.rs
@@ -0,0 +1,959 @@
+//! AST walker. Each overridden visit method has full control over what
+//! happens with its node, it can do its own traversal of the node's children,
+//! call `visit::walk_*` to apply the default traversal algorithm, or prevent
+//! deeper traversal by doing nothing.
+//!
+//! Note: it is an important invariant that the default visitor walks the body
+//! of a function in "execution order" (more concretely, reverse post-order
+//! with respect to the CFG implied by the AST), meaning that if AST node A may
+//! execute before AST node B, then A is visited first. The borrow checker in
+//! particular relies on this property.
+//!
+//! Note: walking an AST before macro expansion is probably a bad idea. For
+//! instance, a walker looking for item names in a module will miss all of
+//! those that are created by the expansion of a macro.
+
+use crate::ast::*;
+
+use rustc_span::symbol::Ident;
+use rustc_span::Span;
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum AssocCtxt {
+ Trait,
+ Impl,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum FnCtxt {
+ Free,
+ Foreign,
+ Assoc(AssocCtxt),
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum BoundKind {
+ /// Trait bounds in generics bounds and type/trait alias.
+ /// E.g., `<T: Bound>`, `type A: Bound`, or `where T: Bound`.
+ Bound,
+
+ /// Trait bounds in `impl` type.
+ /// E.g., `type Foo = impl Bound1 + Bound2 + Bound3`.
+ Impl,
+
+ /// Trait bounds in trait object type.
+ /// E.g., `dyn Bound1 + Bound2 + Bound3`.
+ TraitObject,
+
+ /// Super traits of a trait.
+ /// E.g., `trait A: B`
+ SuperTraits,
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum FnKind<'a> {
+ /// E.g., `fn foo()`, `fn foo(&self)`, or `extern "Abi" fn foo()`.
+ Fn(FnCtxt, Ident, &'a FnSig, &'a Visibility, &'a Generics, Option<&'a Block>),
+
+ /// E.g., `|x, y| body`.
+ Closure(&'a ClosureBinder, &'a FnDecl, &'a Expr),
+}
+
+impl<'a> FnKind<'a> {
+ pub fn header(&self) -> Option<&'a FnHeader> {
+ match *self {
+ FnKind::Fn(_, _, sig, _, _, _) => Some(&sig.header),
+ FnKind::Closure(_, _, _) => None,
+ }
+ }
+
+ pub fn ident(&self) -> Option<&Ident> {
+ match self {
+ FnKind::Fn(_, ident, ..) => Some(ident),
+ _ => None,
+ }
+ }
+
+ pub fn decl(&self) -> &'a FnDecl {
+ match self {
+ FnKind::Fn(_, _, sig, _, _, _) => &sig.decl,
+ FnKind::Closure(_, decl, _) => decl,
+ }
+ }
+
+ pub fn ctxt(&self) -> Option<FnCtxt> {
+ match self {
+ FnKind::Fn(ctxt, ..) => Some(*ctxt),
+ FnKind::Closure(..) => None,
+ }
+ }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum LifetimeCtxt {
+ /// Appears in a reference type.
+ Rptr,
+ /// Appears as a bound on a type or another lifetime.
+ Bound,
+ /// Appears as a generic argument.
+ GenericArg,
+}
+
+/// Each method of the `Visitor` trait is a hook to be potentially
+/// overridden. Each method's default implementation recursively visits
+/// the substructure of the input via the corresponding `walk` method;
+/// e.g., the `visit_item` method by default calls `visit::walk_item`.
+///
+/// If you want to ensure that your code handles every variant
+/// explicitly, you need to override each method. (And you also need
+/// to monitor future changes to `Visitor` in case a new method with a
+/// new default implementation gets introduced.)
+pub trait Visitor<'ast>: Sized {
+ fn visit_ident(&mut self, _ident: Ident) {}
+ fn visit_foreign_item(&mut self, i: &'ast ForeignItem) {
+ walk_foreign_item(self, i)
+ }
+ fn visit_item(&mut self, i: &'ast Item) {
+ walk_item(self, i)
+ }
+ fn visit_local(&mut self, l: &'ast Local) {
+ walk_local(self, l)
+ }
+ fn visit_block(&mut self, b: &'ast Block) {
+ walk_block(self, b)
+ }
+ fn visit_stmt(&mut self, s: &'ast Stmt) {
+ walk_stmt(self, s)
+ }
+ fn visit_param(&mut self, param: &'ast Param) {
+ walk_param(self, param)
+ }
+ fn visit_arm(&mut self, a: &'ast Arm) {
+ walk_arm(self, a)
+ }
+ fn visit_pat(&mut self, p: &'ast Pat) {
+ walk_pat(self, p)
+ }
+ fn visit_anon_const(&mut self, c: &'ast AnonConst) {
+ walk_anon_const(self, c)
+ }
+ fn visit_expr(&mut self, ex: &'ast Expr) {
+ walk_expr(self, ex)
+ }
+ fn visit_expr_post(&mut self, _ex: &'ast Expr) {}
+ fn visit_ty(&mut self, t: &'ast Ty) {
+ walk_ty(self, t)
+ }
+ fn visit_generic_param(&mut self, param: &'ast GenericParam) {
+ walk_generic_param(self, param)
+ }
+ fn visit_generics(&mut self, g: &'ast Generics) {
+ walk_generics(self, g)
+ }
+ fn visit_closure_binder(&mut self, b: &'ast ClosureBinder) {
+ walk_closure_binder(self, b)
+ }
+ fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
+ walk_where_predicate(self, p)
+ }
+ fn visit_fn(&mut self, fk: FnKind<'ast>, s: Span, _: NodeId) {
+ walk_fn(self, fk, s)
+ }
+ fn visit_assoc_item(&mut self, i: &'ast AssocItem, ctxt: AssocCtxt) {
+ walk_assoc_item(self, i, ctxt)
+ }
+ fn visit_trait_ref(&mut self, t: &'ast TraitRef) {
+ walk_trait_ref(self, t)
+ }
+ fn visit_param_bound(&mut self, bounds: &'ast GenericBound, _ctxt: BoundKind) {
+ walk_param_bound(self, bounds)
+ }
+ fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
+ walk_poly_trait_ref(self, t, m)
+ }
+ fn visit_variant_data(&mut self, s: &'ast VariantData) {
+ walk_struct_def(self, s)
+ }
+ fn visit_field_def(&mut self, s: &'ast FieldDef) {
+ walk_field_def(self, s)
+ }
+ fn visit_enum_def(
+ &mut self,
+ enum_definition: &'ast EnumDef,
+ generics: &'ast Generics,
+ item_id: NodeId,
+ _: Span,
+ ) {
+ walk_enum_def(self, enum_definition, generics, item_id)
+ }
+ fn visit_variant(&mut self, v: &'ast Variant) {
+ walk_variant(self, v)
+ }
+ fn visit_label(&mut self, label: &'ast Label) {
+ walk_label(self, label)
+ }
+ fn visit_lifetime(&mut self, lifetime: &'ast Lifetime, _: LifetimeCtxt) {
+ walk_lifetime(self, lifetime)
+ }
+ fn visit_mac_call(&mut self, mac: &'ast MacCall) {
+ walk_mac(self, mac)
+ }
+ fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
+ // Nothing to do
+ }
+ fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
+ walk_path(self, path)
+ }
+ fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
+ walk_use_tree(self, use_tree, id)
+ }
+ fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
+ walk_path_segment(self, path_span, path_segment)
+ }
+ fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
+ walk_generic_args(self, path_span, generic_args)
+ }
+ fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
+ walk_generic_arg(self, generic_arg)
+ }
+ fn visit_assoc_constraint(&mut self, constraint: &'ast AssocConstraint) {
+ walk_assoc_constraint(self, constraint)
+ }
+ fn visit_attribute(&mut self, attr: &'ast Attribute) {
+ walk_attribute(self, attr)
+ }
+ fn visit_vis(&mut self, vis: &'ast Visibility) {
+ walk_vis(self, vis)
+ }
+ fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FnRetTy) {
+ walk_fn_ret_ty(self, ret_ty)
+ }
+ fn visit_fn_header(&mut self, _header: &'ast FnHeader) {
+ // Nothing to do
+ }
+ fn visit_expr_field(&mut self, f: &'ast ExprField) {
+ walk_expr_field(self, f)
+ }
+ fn visit_pat_field(&mut self, fp: &'ast PatField) {
+ walk_pat_field(self, fp)
+ }
+ fn visit_crate(&mut self, krate: &'ast Crate) {
+ walk_crate(self, krate)
+ }
+ fn visit_inline_asm(&mut self, asm: &'ast InlineAsm) {
+ walk_inline_asm(self, asm)
+ }
+ fn visit_inline_asm_sym(&mut self, sym: &'ast InlineAsmSym) {
+ walk_inline_asm_sym(self, sym)
+ }
+}
+
+#[macro_export]
+macro_rules! walk_list {
+ ($visitor: expr, $method: ident, $list: expr) => {
+ for elem in $list {
+ $visitor.$method(elem)
+ }
+ };
+ ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
+ for elem in $list {
+ $visitor.$method(elem, $($extra_args,)*)
+ }
+ }
+}
+
+pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
+ walk_list!(visitor, visit_item, &krate.items);
+ walk_list!(visitor, visit_attribute, &krate.attrs);
+}
+
+pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
+ for attr in local.attrs.iter() {
+ visitor.visit_attribute(attr);
+ }
+ visitor.visit_pat(&local.pat);
+ walk_list!(visitor, visit_ty, &local.ty);
+ if let Some((init, els)) = local.kind.init_else_opt() {
+ visitor.visit_expr(init);
+ walk_list!(visitor, visit_block, els);
+ }
+}
+
+pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
+ visitor.visit_ident(label.ident);
+}
+
+pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
+ visitor.visit_ident(lifetime.ident);
+}
+
+pub fn walk_poly_trait_ref<'a, V>(
+ visitor: &mut V,
+ trait_ref: &'a PolyTraitRef,
+ _: &TraitBoundModifier,
+) where
+ V: Visitor<'a>,
+{
+ walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
+ visitor.visit_trait_ref(&trait_ref.trait_ref);
+}
+
+pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
+ visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
+}
+
+pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
+ visitor.visit_vis(&item.vis);
+ visitor.visit_ident(item.ident);
+ match item.kind {
+ ItemKind::ExternCrate(_) => {}
+ ItemKind::Use(ref use_tree) => visitor.visit_use_tree(use_tree, item.id, false),
+ ItemKind::Static(ref typ, _, ref expr) | ItemKind::Const(_, ref typ, ref expr) => {
+ visitor.visit_ty(typ);
+ walk_list!(visitor, visit_expr, expr);
+ }
+ ItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
+ let kind =
+ FnKind::Fn(FnCtxt::Free, item.ident, sig, &item.vis, generics, body.as_deref());
+ visitor.visit_fn(kind, item.span, item.id)
+ }
+ ItemKind::Mod(_unsafety, ref mod_kind) => match mod_kind {
+ ModKind::Loaded(items, _inline, _inner_span) => {
+ walk_list!(visitor, visit_item, items)
+ }
+ ModKind::Unloaded => {}
+ },
+ ItemKind::ForeignMod(ref foreign_module) => {
+ walk_list!(visitor, visit_foreign_item, &foreign_module.items);
+ }
+ ItemKind::GlobalAsm(ref asm) => visitor.visit_inline_asm(asm),
+ ItemKind::TyAlias(box TyAlias { ref generics, ref bounds, ref ty, .. }) => {
+ visitor.visit_generics(generics);
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
+ walk_list!(visitor, visit_ty, ty);
+ }
+ ItemKind::Enum(ref enum_definition, ref generics) => {
+ visitor.visit_generics(generics);
+ visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
+ }
+ ItemKind::Impl(box Impl {
+ defaultness: _,
+ unsafety: _,
+ ref generics,
+ constness: _,
+ polarity: _,
+ ref of_trait,
+ ref self_ty,
+ ref items,
+ }) => {
+ visitor.visit_generics(generics);
+ walk_list!(visitor, visit_trait_ref, of_trait);
+ visitor.visit_ty(self_ty);
+ walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Impl);
+ }
+ ItemKind::Struct(ref struct_definition, ref generics)
+ | ItemKind::Union(ref struct_definition, ref generics) => {
+ visitor.visit_generics(generics);
+ visitor.visit_variant_data(struct_definition);
+ }
+ ItemKind::Trait(box Trait {
+ unsafety: _,
+ is_auto: _,
+ ref generics,
+ ref bounds,
+ ref items,
+ }) => {
+ visitor.visit_generics(generics);
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::SuperTraits);
+ walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Trait);
+ }
+ ItemKind::TraitAlias(ref generics, ref bounds) => {
+ visitor.visit_generics(generics);
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
+ }
+ ItemKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
+ ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
+ }
+ walk_list!(visitor, visit_attribute, &item.attrs);
+}
+
+pub fn walk_enum_def<'a, V: Visitor<'a>>(
+ visitor: &mut V,
+ enum_definition: &'a EnumDef,
+ _: &'a Generics,
+ _: NodeId,
+) {
+ walk_list!(visitor, visit_variant, &enum_definition.variants);
+}
+
+pub fn walk_variant<'a, V: Visitor<'a>>(visitor: &mut V, variant: &'a Variant)
+where
+ V: Visitor<'a>,
+{
+ visitor.visit_ident(variant.ident);
+ visitor.visit_vis(&variant.vis);
+ visitor.visit_variant_data(&variant.data);
+ walk_list!(visitor, visit_anon_const, &variant.disr_expr);
+ walk_list!(visitor, visit_attribute, &variant.attrs);
+}
+
+pub fn walk_expr_field<'a, V: Visitor<'a>>(visitor: &mut V, f: &'a ExprField) {
+ visitor.visit_expr(&f.expr);
+ visitor.visit_ident(f.ident);
+ walk_list!(visitor, visit_attribute, f.attrs.iter());
+}
+
+pub fn walk_pat_field<'a, V: Visitor<'a>>(visitor: &mut V, fp: &'a PatField) {
+ visitor.visit_ident(fp.ident);
+ visitor.visit_pat(&fp.pat);
+ walk_list!(visitor, visit_attribute, fp.attrs.iter());
+}
+
+pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
+ match typ.kind {
+ TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => visitor.visit_ty(ty),
+ TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
+ TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
+ walk_list!(visitor, visit_lifetime, opt_lifetime, LifetimeCtxt::Rptr);
+ visitor.visit_ty(&mutable_type.ty)
+ }
+ TyKind::Tup(ref tuple_element_types) => {
+ walk_list!(visitor, visit_ty, tuple_element_types);
+ }
+ TyKind::BareFn(ref function_declaration) => {
+ walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
+ walk_fn_decl(visitor, &function_declaration.decl);
+ }
+ TyKind::Path(ref maybe_qself, ref path) => {
+ if let Some(ref qself) = *maybe_qself {
+ visitor.visit_ty(&qself.ty);
+ }
+ visitor.visit_path(path, typ.id);
+ }
+ TyKind::Array(ref ty, ref length) => {
+ visitor.visit_ty(ty);
+ visitor.visit_anon_const(length)
+ }
+ TyKind::TraitObject(ref bounds, ..) => {
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::TraitObject);
+ }
+ TyKind::ImplTrait(_, ref bounds) => {
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Impl);
+ }
+ TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
+ TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
+ TyKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
+ TyKind::Never | TyKind::CVarArgs => {}
+ }
+}
+
+pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
+ for segment in &path.segments {
+ visitor.visit_path_segment(path.span, segment);
+ }
+}
+
+pub fn walk_use_tree<'a, V: Visitor<'a>>(visitor: &mut V, use_tree: &'a UseTree, id: NodeId) {
+ visitor.visit_path(&use_tree.prefix, id);
+ match use_tree.kind {
+ UseTreeKind::Simple(rename, ..) => {
+ // The extra IDs are handled during HIR lowering.
+ if let Some(rename) = rename {
+ visitor.visit_ident(rename);
+ }
+ }
+ UseTreeKind::Glob => {}
+ UseTreeKind::Nested(ref use_trees) => {
+ for &(ref nested_tree, nested_id) in use_trees {
+ visitor.visit_use_tree(nested_tree, nested_id, true);
+ }
+ }
+ }
+}
+
+pub fn walk_path_segment<'a, V: Visitor<'a>>(
+ visitor: &mut V,
+ path_span: Span,
+ segment: &'a PathSegment,
+) {
+ visitor.visit_ident(segment.ident);
+ if let Some(ref args) = segment.args {
+ visitor.visit_generic_args(path_span, args);
+ }
+}
+
+pub fn walk_generic_args<'a, V>(visitor: &mut V, _path_span: Span, generic_args: &'a GenericArgs)
+where
+ V: Visitor<'a>,
+{
+ match *generic_args {
+ GenericArgs::AngleBracketed(ref data) => {
+ for arg in &data.args {
+ match arg {
+ AngleBracketedArg::Arg(a) => visitor.visit_generic_arg(a),
+ AngleBracketedArg::Constraint(c) => visitor.visit_assoc_constraint(c),
+ }
+ }
+ }
+ GenericArgs::Parenthesized(ref data) => {
+ walk_list!(visitor, visit_ty, &data.inputs);
+ walk_fn_ret_ty(visitor, &data.output);
+ }
+ }
+}
+
+pub fn walk_generic_arg<'a, V>(visitor: &mut V, generic_arg: &'a GenericArg)
+where
+ V: Visitor<'a>,
+{
+ match generic_arg {
+ GenericArg::Lifetime(lt) => visitor.visit_lifetime(lt, LifetimeCtxt::GenericArg),
+ GenericArg::Type(ty) => visitor.visit_ty(ty),
+ GenericArg::Const(ct) => visitor.visit_anon_const(ct),
+ }
+}
+
+pub fn walk_assoc_constraint<'a, V: Visitor<'a>>(visitor: &mut V, constraint: &'a AssocConstraint) {
+ visitor.visit_ident(constraint.ident);
+ if let Some(ref gen_args) = constraint.gen_args {
+ visitor.visit_generic_args(gen_args.span(), gen_args);
+ }
+ match constraint.kind {
+ AssocConstraintKind::Equality { ref term } => match term {
+ Term::Ty(ty) => visitor.visit_ty(ty),
+ Term::Const(c) => visitor.visit_anon_const(c),
+ },
+ AssocConstraintKind::Bound { ref bounds } => {
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
+ }
+ }
+}
+
+pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
+ match pattern.kind {
+ PatKind::TupleStruct(ref opt_qself, ref path, ref elems) => {
+ if let Some(ref qself) = *opt_qself {
+ visitor.visit_ty(&qself.ty);
+ }
+ visitor.visit_path(path, pattern.id);
+ walk_list!(visitor, visit_pat, elems);
+ }
+ PatKind::Path(ref opt_qself, ref path) => {
+ if let Some(ref qself) = *opt_qself {
+ visitor.visit_ty(&qself.ty);
+ }
+ visitor.visit_path(path, pattern.id)
+ }
+ PatKind::Struct(ref opt_qself, ref path, ref fields, _) => {
+ if let Some(ref qself) = *opt_qself {
+ visitor.visit_ty(&qself.ty);
+ }
+ visitor.visit_path(path, pattern.id);
+ walk_list!(visitor, visit_pat_field, fields);
+ }
+ PatKind::Box(ref subpattern)
+ | PatKind::Ref(ref subpattern, _)
+ | PatKind::Paren(ref subpattern) => visitor.visit_pat(subpattern),
+ PatKind::Ident(_, ident, ref optional_subpattern) => {
+ visitor.visit_ident(ident);
+ walk_list!(visitor, visit_pat, optional_subpattern);
+ }
+ PatKind::Lit(ref expression) => visitor.visit_expr(expression),
+ PatKind::Range(ref lower_bound, ref upper_bound, _) => {
+ walk_list!(visitor, visit_expr, lower_bound);
+ walk_list!(visitor, visit_expr, upper_bound);
+ }
+ PatKind::Wild | PatKind::Rest => {}
+ PatKind::Tuple(ref elems) | PatKind::Slice(ref elems) | PatKind::Or(ref elems) => {
+ walk_list!(visitor, visit_pat, elems);
+ }
+ PatKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
+ }
+}
+
+pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a ForeignItem) {
+ let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
+ visitor.visit_vis(vis);
+ visitor.visit_ident(ident);
+ walk_list!(visitor, visit_attribute, attrs);
+ match kind {
+ ForeignItemKind::Static(ty, _, expr) => {
+ visitor.visit_ty(ty);
+ walk_list!(visitor, visit_expr, expr);
+ }
+ ForeignItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
+ let kind = FnKind::Fn(FnCtxt::Foreign, ident, sig, vis, generics, body.as_deref());
+ visitor.visit_fn(kind, span, id);
+ }
+ ForeignItemKind::TyAlias(box TyAlias { generics, bounds, ty, .. }) => {
+ visitor.visit_generics(generics);
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
+ walk_list!(visitor, visit_ty, ty);
+ }
+ ForeignItemKind::MacCall(mac) => {
+ visitor.visit_mac_call(mac);
+ }
+ }
+}
+
+pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
+ match *bound {
+ GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
+ GenericBound::Outlives(ref lifetime) => {
+ visitor.visit_lifetime(lifetime, LifetimeCtxt::Bound)
+ }
+ }
+}
+
+pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
+ visitor.visit_ident(param.ident);
+ walk_list!(visitor, visit_attribute, param.attrs.iter());
+ walk_list!(visitor, visit_param_bound, &param.bounds, BoundKind::Bound);
+ match param.kind {
+ GenericParamKind::Lifetime => (),
+ GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
+ GenericParamKind::Const { ref ty, ref default, .. } => {
+ visitor.visit_ty(ty);
+ if let Some(default) = default {
+ visitor.visit_anon_const(default);
+ }
+ }
+ }
+}
+
+pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
+ walk_list!(visitor, visit_generic_param, &generics.params);
+ walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
+}
+
+pub fn walk_closure_binder<'a, V: Visitor<'a>>(visitor: &mut V, binder: &'a ClosureBinder) {
+ match binder {
+ ClosureBinder::NotPresent => {}
+ ClosureBinder::For { generic_params, span: _ } => {
+ walk_list!(visitor, visit_generic_param, generic_params)
+ }
+ }
+}
+
+pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
+ match *predicate {
+ WherePredicate::BoundPredicate(WhereBoundPredicate {
+ ref bounded_ty,
+ ref bounds,
+ ref bound_generic_params,
+ ..
+ }) => {
+ visitor.visit_ty(bounded_ty);
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
+ walk_list!(visitor, visit_generic_param, bound_generic_params);
+ }
+ WherePredicate::RegionPredicate(WhereRegionPredicate {
+ ref lifetime, ref bounds, ..
+ }) => {
+ visitor.visit_lifetime(lifetime, LifetimeCtxt::Bound);
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
+ }
+ WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, .. }) => {
+ visitor.visit_ty(lhs_ty);
+ visitor.visit_ty(rhs_ty);
+ }
+ }
+}
+
+pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FnRetTy) {
+ if let FnRetTy::Ty(ref output_ty) = *ret_ty {
+ visitor.visit_ty(output_ty)
+ }
+}
+
+pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
+ for param in &function_declaration.inputs {
+ visitor.visit_param(param);
+ }
+ visitor.visit_fn_ret_ty(&function_declaration.output);
+}
+
+pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>, _span: Span) {
+ match kind {
+ FnKind::Fn(_, _, sig, _, generics, body) => {
+ visitor.visit_generics(generics);
+ visitor.visit_fn_header(&sig.header);
+ walk_fn_decl(visitor, &sig.decl);
+ walk_list!(visitor, visit_block, body);
+ }
+ FnKind::Closure(binder, decl, body) => {
+ visitor.visit_closure_binder(binder);
+ walk_fn_decl(visitor, decl);
+ visitor.visit_expr(body);
+ }
+ }
+}
+
+pub fn walk_assoc_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem, ctxt: AssocCtxt) {
+ let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
+ visitor.visit_vis(vis);
+ visitor.visit_ident(ident);
+ walk_list!(visitor, visit_attribute, attrs);
+ match kind {
+ AssocItemKind::Const(_, ty, expr) => {
+ visitor.visit_ty(ty);
+ walk_list!(visitor, visit_expr, expr);
+ }
+ AssocItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
+ let kind = FnKind::Fn(FnCtxt::Assoc(ctxt), ident, sig, vis, generics, body.as_deref());
+ visitor.visit_fn(kind, span, id);
+ }
+ AssocItemKind::TyAlias(box TyAlias { generics, bounds, ty, .. }) => {
+ visitor.visit_generics(generics);
+ walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
+ walk_list!(visitor, visit_ty, ty);
+ }
+ AssocItemKind::MacCall(mac) => {
+ visitor.visit_mac_call(mac);
+ }
+ }
+}
+
+pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
+ walk_list!(visitor, visit_field_def, struct_definition.fields());
+}
+
+pub fn walk_field_def<'a, V: Visitor<'a>>(visitor: &mut V, field: &'a FieldDef) {
+ visitor.visit_vis(&field.vis);
+ if let Some(ident) = field.ident {
+ visitor.visit_ident(ident);
+ }
+ visitor.visit_ty(&field.ty);
+ walk_list!(visitor, visit_attribute, &field.attrs);
+}
+
+pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
+ walk_list!(visitor, visit_stmt, &block.stmts);
+}
+
+pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
+ match statement.kind {
+ StmtKind::Local(ref local) => visitor.visit_local(local),
+ StmtKind::Item(ref item) => visitor.visit_item(item),
+ StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => visitor.visit_expr(expr),
+ StmtKind::Empty => {}
+ StmtKind::MacCall(ref mac) => {
+ let MacCallStmt { ref mac, style: _, ref attrs, tokens: _ } = **mac;
+ visitor.visit_mac_call(mac);
+ for attr in attrs.iter() {
+ visitor.visit_attribute(attr);
+ }
+ }
+ }
+}
+
+pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a MacCall) {
+ visitor.visit_path(&mac.path, DUMMY_NODE_ID);
+}
+
+pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
+ visitor.visit_expr(&constant.value);
+}
+
+pub fn walk_inline_asm<'a, V: Visitor<'a>>(visitor: &mut V, asm: &'a InlineAsm) {
+ for (op, _) in &asm.operands {
+ match op {
+ InlineAsmOperand::In { expr, .. }
+ | InlineAsmOperand::Out { expr: Some(expr), .. }
+ | InlineAsmOperand::InOut { expr, .. } => visitor.visit_expr(expr),
+ InlineAsmOperand::Out { expr: None, .. } => {}
+ InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
+ visitor.visit_expr(in_expr);
+ if let Some(out_expr) = out_expr {
+ visitor.visit_expr(out_expr);
+ }
+ }
+ InlineAsmOperand::Const { anon_const, .. } => visitor.visit_anon_const(anon_const),
+ InlineAsmOperand::Sym { sym } => visitor.visit_inline_asm_sym(sym),
+ }
+ }
+}
+
+pub fn walk_inline_asm_sym<'a, V: Visitor<'a>>(visitor: &mut V, sym: &'a InlineAsmSym) {
+ if let Some(ref qself) = sym.qself {
+ visitor.visit_ty(&qself.ty);
+ }
+ visitor.visit_path(&sym.path, sym.id);
+}
+
+pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
+ walk_list!(visitor, visit_attribute, expression.attrs.iter());
+
+ match expression.kind {
+ ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
+ ExprKind::Array(ref subexpressions) => {
+ walk_list!(visitor, visit_expr, subexpressions);
+ }
+ ExprKind::ConstBlock(ref anon_const) => visitor.visit_anon_const(anon_const),
+ ExprKind::Repeat(ref element, ref count) => {
+ visitor.visit_expr(element);
+ visitor.visit_anon_const(count)
+ }
+ ExprKind::Struct(ref se) => {
+ if let Some(ref qself) = se.qself {
+ visitor.visit_ty(&qself.ty);
+ }
+ visitor.visit_path(&se.path, expression.id);
+ walk_list!(visitor, visit_expr_field, &se.fields);
+ match &se.rest {
+ StructRest::Base(expr) => visitor.visit_expr(expr),
+ StructRest::Rest(_span) => {}
+ StructRest::None => {}
+ }
+ }
+ ExprKind::Tup(ref subexpressions) => {
+ walk_list!(visitor, visit_expr, subexpressions);
+ }
+ ExprKind::Call(ref callee_expression, ref arguments) => {
+ visitor.visit_expr(callee_expression);
+ walk_list!(visitor, visit_expr, arguments);
+ }
+ ExprKind::MethodCall(ref segment, ref arguments, _span) => {
+ visitor.visit_path_segment(expression.span, segment);
+ walk_list!(visitor, visit_expr, arguments);
+ }
+ ExprKind::Binary(_, ref left_expression, ref right_expression) => {
+ visitor.visit_expr(left_expression);
+ visitor.visit_expr(right_expression)
+ }
+ ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
+ visitor.visit_expr(subexpression)
+ }
+ ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
+ visitor.visit_expr(subexpression);
+ visitor.visit_ty(typ)
+ }
+ ExprKind::Let(ref pat, ref expr, _) => {
+ visitor.visit_pat(pat);
+ visitor.visit_expr(expr);
+ }
+ ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
+ visitor.visit_expr(head_expression);
+ visitor.visit_block(if_block);
+ walk_list!(visitor, visit_expr, optional_else);
+ }
+ ExprKind::While(ref subexpression, ref block, ref opt_label) => {
+ walk_list!(visitor, visit_label, opt_label);
+ visitor.visit_expr(subexpression);
+ visitor.visit_block(block);
+ }
+ ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
+ walk_list!(visitor, visit_label, opt_label);
+ visitor.visit_pat(pattern);
+ visitor.visit_expr(subexpression);
+ visitor.visit_block(block);
+ }
+ ExprKind::Loop(ref block, ref opt_label) => {
+ walk_list!(visitor, visit_label, opt_label);
+ visitor.visit_block(block);
+ }
+ ExprKind::Match(ref subexpression, ref arms) => {
+ visitor.visit_expr(subexpression);
+ walk_list!(visitor, visit_arm, arms);
+ }
+ ExprKind::Closure(ref binder, _, _, _, ref decl, ref body, _decl_span) => {
+ visitor.visit_fn(FnKind::Closure(binder, decl, body), expression.span, expression.id)
+ }
+ ExprKind::Block(ref block, ref opt_label) => {
+ walk_list!(visitor, visit_label, opt_label);
+ visitor.visit_block(block);
+ }
+ ExprKind::Async(_, _, ref body) => {
+ visitor.visit_block(body);
+ }
+ ExprKind::Await(ref expr) => visitor.visit_expr(expr),
+ ExprKind::Assign(ref lhs, ref rhs, _) => {
+ visitor.visit_expr(lhs);
+ visitor.visit_expr(rhs);
+ }
+ ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
+ visitor.visit_expr(left_expression);
+ visitor.visit_expr(right_expression);
+ }
+ ExprKind::Field(ref subexpression, ident) => {
+ visitor.visit_expr(subexpression);
+ visitor.visit_ident(ident);
+ }
+ ExprKind::Index(ref main_expression, ref index_expression) => {
+ visitor.visit_expr(main_expression);
+ visitor.visit_expr(index_expression)
+ }
+ ExprKind::Range(ref start, ref end, _) => {
+ walk_list!(visitor, visit_expr, start);
+ walk_list!(visitor, visit_expr, end);
+ }
+ ExprKind::Underscore => {}
+ ExprKind::Path(ref maybe_qself, ref path) => {
+ if let Some(ref qself) = *maybe_qself {
+ visitor.visit_ty(&qself.ty);
+ }
+ visitor.visit_path(path, expression.id)
+ }
+ ExprKind::Break(ref opt_label, ref opt_expr) => {
+ walk_list!(visitor, visit_label, opt_label);
+ walk_list!(visitor, visit_expr, opt_expr);
+ }
+ ExprKind::Continue(ref opt_label) => {
+ walk_list!(visitor, visit_label, opt_label);
+ }
+ ExprKind::Ret(ref optional_expression) => {
+ walk_list!(visitor, visit_expr, optional_expression);
+ }
+ ExprKind::Yeet(ref optional_expression) => {
+ walk_list!(visitor, visit_expr, optional_expression);
+ }
+ ExprKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
+ ExprKind::Paren(ref subexpression) => visitor.visit_expr(subexpression),
+ ExprKind::InlineAsm(ref asm) => visitor.visit_inline_asm(asm),
+ ExprKind::Yield(ref optional_expression) => {
+ walk_list!(visitor, visit_expr, optional_expression);
+ }
+ ExprKind::Try(ref subexpression) => visitor.visit_expr(subexpression),
+ ExprKind::TryBlock(ref body) => visitor.visit_block(body),
+ ExprKind::Lit(_) | ExprKind::Err => {}
+ }
+
+ visitor.visit_expr_post(expression)
+}
+
+pub fn walk_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a Param) {
+ walk_list!(visitor, visit_attribute, param.attrs.iter());
+ visitor.visit_pat(&param.pat);
+ visitor.visit_ty(&param.ty);
+}
+
+pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
+ visitor.visit_pat(&arm.pat);
+ walk_list!(visitor, visit_expr, &arm.guard);
+ visitor.visit_expr(&arm.body);
+ walk_list!(visitor, visit_attribute, &arm.attrs);
+}
+
+pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
+ if let VisibilityKind::Restricted { ref path, id } = vis.kind {
+ visitor.visit_path(path, id);
+ }
+}
+
+pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
+ match attr.kind {
+ AttrKind::Normal(ref item, ref _tokens) => walk_mac_args(visitor, &item.args),
+ AttrKind::DocComment(..) => {}
+ }
+}
+
+pub fn walk_mac_args<'a, V: Visitor<'a>>(visitor: &mut V, args: &'a MacArgs) {
+ match args {
+ MacArgs::Empty => {}
+ MacArgs::Delimited(_dspan, _delim, _tokens) => {}
+ MacArgs::Eq(_eq_span, MacArgsEq::Ast(expr)) => visitor.visit_expr(expr),
+ MacArgs::Eq(_, MacArgsEq::Hir(lit)) => {
+ unreachable!("in literal form when walking mac args eq: {:?}", lit)
+ }
+ }
+}