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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
| commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
| tree | 173a775858bd501c378080a10dca74132f05bc50 /compiler/rustc_ast/src/ast.rs | |
| parent | Initial commit. (diff) | |
| download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip | |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_ast/src/ast.rs')
| -rw-r--r-- | compiler/rustc_ast/src/ast.rs | 3051 |
1 files changed, 3051 insertions, 0 deletions
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); +} |