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Diffstat (limited to 'vendor/syn/src/expr.rs')
| -rw-r--r-- | vendor/syn/src/expr.rs | 3506 |
1 files changed, 3506 insertions, 0 deletions
diff --git a/vendor/syn/src/expr.rs b/vendor/syn/src/expr.rs new file mode 100644 index 0000000..7fb0f7b --- /dev/null +++ b/vendor/syn/src/expr.rs @@ -0,0 +1,3506 @@ +use super::*; +use crate::punctuated::Punctuated; +use proc_macro2::{Span, TokenStream}; +#[cfg(feature = "printing")] +use quote::IdentFragment; +#[cfg(feature = "printing")] +use std::fmt::{self, Display}; +use std::hash::{Hash, Hasher}; +#[cfg(feature = "parsing")] +use std::mem; + +ast_enum_of_structs! { + /// A Rust expression. + /// + /// *This type is available only if Syn is built with the `"derive"` or `"full"` + /// feature, but most of the variants are not available unless "full" is enabled.* + /// + /// # Syntax tree enums + /// + /// This type is a syntax tree enum. In Syn this and other syntax tree enums + /// are designed to be traversed using the following rebinding idiom. + /// + /// ``` + /// # use syn::Expr; + /// # + /// # fn example(expr: Expr) { + /// # const IGNORE: &str = stringify! { + /// let expr: Expr = /* ... */; + /// # }; + /// match expr { + /// Expr::MethodCall(expr) => { + /// /* ... */ + /// } + /// Expr::Cast(expr) => { + /// /* ... */ + /// } + /// Expr::If(expr) => { + /// /* ... */ + /// } + /// + /// /* ... */ + /// # _ => {} + /// # } + /// # } + /// ``` + /// + /// We begin with a variable `expr` of type `Expr` that has no fields + /// (because it is an enum), and by matching on it and rebinding a variable + /// with the same name `expr` we effectively imbue our variable with all of + /// the data fields provided by the variant that it turned out to be. So for + /// example above if we ended up in the `MethodCall` case then we get to use + /// `expr.receiver`, `expr.args` etc; if we ended up in the `If` case we get + /// to use `expr.cond`, `expr.then_branch`, `expr.else_branch`. + /// + /// This approach avoids repeating the variant names twice on every line. + /// + /// ``` + /// # use syn::{Expr, ExprMethodCall}; + /// # + /// # fn example(expr: Expr) { + /// // Repetitive; recommend not doing this. + /// match expr { + /// Expr::MethodCall(ExprMethodCall { method, args, .. }) => { + /// # } + /// # _ => {} + /// # } + /// # } + /// ``` + /// + /// In general, the name to which a syntax tree enum variant is bound should + /// be a suitable name for the complete syntax tree enum type. + /// + /// ``` + /// # use syn::{Expr, ExprField}; + /// # + /// # fn example(discriminant: ExprField) { + /// // Binding is called `base` which is the name I would use if I were + /// // assigning `*discriminant.base` without an `if let`. + /// if let Expr::Tuple(base) = *discriminant.base { + /// # } + /// # } + /// ``` + /// + /// A sign that you may not be choosing the right variable names is if you + /// see names getting repeated in your code, like accessing + /// `receiver.receiver` or `pat.pat` or `cond.cond`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + #[non_exhaustive] + pub enum Expr { + /// A slice literal expression: `[a, b, c, d]`. + Array(ExprArray), + + /// An assignment expression: `a = compute()`. + Assign(ExprAssign), + + /// An async block: `async { ... }`. + Async(ExprAsync), + + /// An await expression: `fut.await`. + Await(ExprAwait), + + /// A binary operation: `a + b`, `a += b`. + Binary(ExprBinary), + + /// A blocked scope: `{ ... }`. + Block(ExprBlock), + + /// A `break`, with an optional label to break and an optional + /// expression. + Break(ExprBreak), + + /// A function call expression: `invoke(a, b)`. + Call(ExprCall), + + /// A cast expression: `foo as f64`. + Cast(ExprCast), + + /// A closure expression: `|a, b| a + b`. + Closure(ExprClosure), + + /// A const block: `const { ... }`. + Const(ExprConst), + + /// A `continue`, with an optional label. + Continue(ExprContinue), + + /// Access of a named struct field (`obj.k`) or unnamed tuple struct + /// field (`obj.0`). + Field(ExprField), + + /// A for loop: `for pat in expr { ... }`. + ForLoop(ExprForLoop), + + /// An expression contained within invisible delimiters. + /// + /// This variant is important for faithfully representing the precedence + /// of expressions and is related to `None`-delimited spans in a + /// `TokenStream`. + Group(ExprGroup), + + /// An `if` expression with an optional `else` block: `if expr { ... } + /// else { ... }`. + /// + /// The `else` branch expression may only be an `If` or `Block` + /// expression, not any of the other types of expression. + If(ExprIf), + + /// A square bracketed indexing expression: `vector[2]`. + Index(ExprIndex), + + /// The inferred value of a const generic argument, denoted `_`. + Infer(ExprInfer), + + /// A `let` guard: `let Some(x) = opt`. + Let(ExprLet), + + /// A literal in place of an expression: `1`, `"foo"`. + Lit(ExprLit), + + /// Conditionless loop: `loop { ... }`. + Loop(ExprLoop), + + /// A macro invocation expression: `format!("{}", q)`. + Macro(ExprMacro), + + /// A `match` expression: `match n { Some(n) => {}, None => {} }`. + Match(ExprMatch), + + /// A method call expression: `x.foo::<T>(a, b)`. + MethodCall(ExprMethodCall), + + /// A parenthesized expression: `(a + b)`. + Paren(ExprParen), + + /// A path like `std::mem::replace` possibly containing generic + /// parameters and a qualified self-type. + /// + /// A plain identifier like `x` is a path of length 1. + Path(ExprPath), + + /// A range expression: `1..2`, `1..`, `..2`, `1..=2`, `..=2`. + Range(ExprRange), + + /// A referencing operation: `&a` or `&mut a`. + Reference(ExprReference), + + /// An array literal constructed from one repeated element: `[0u8; N]`. + Repeat(ExprRepeat), + + /// A `return`, with an optional value to be returned. + Return(ExprReturn), + + /// A struct literal expression: `Point { x: 1, y: 1 }`. + /// + /// The `rest` provides the value of the remaining fields as in `S { a: + /// 1, b: 1, ..rest }`. + Struct(ExprStruct), + + /// A try-expression: `expr?`. + Try(ExprTry), + + /// A try block: `try { ... }`. + TryBlock(ExprTryBlock), + + /// A tuple expression: `(a, b, c, d)`. + Tuple(ExprTuple), + + /// A unary operation: `!x`, `*x`. + Unary(ExprUnary), + + /// An unsafe block: `unsafe { ... }`. + Unsafe(ExprUnsafe), + + /// Tokens in expression position not interpreted by Syn. + Verbatim(TokenStream), + + /// A while loop: `while expr { ... }`. + While(ExprWhile), + + /// A yield expression: `yield expr`. + Yield(ExprYield), + + // For testing exhaustiveness in downstream code, use the following idiom: + // + // match expr { + // #![cfg_attr(test, deny(non_exhaustive_omitted_patterns))] + // + // Expr::Array(expr) => {...} + // Expr::Assign(expr) => {...} + // ... + // Expr::Yield(expr) => {...} + // + // _ => { /* some sane fallback */ } + // } + // + // This way we fail your tests but don't break your library when adding + // a variant. You will be notified by a test failure when a variant is + // added, so that you can add code to handle it, but your library will + // continue to compile and work for downstream users in the interim. + } +} + +ast_struct! { + /// A slice literal expression: `[a, b, c, d]`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprArray #full { + pub attrs: Vec<Attribute>, + pub bracket_token: token::Bracket, + pub elems: Punctuated<Expr, Token![,]>, + } +} + +ast_struct! { + /// An assignment expression: `a = compute()`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprAssign #full { + pub attrs: Vec<Attribute>, + pub left: Box<Expr>, + pub eq_token: Token![=], + pub right: Box<Expr>, + } +} + +ast_struct! { + /// An async block: `async { ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprAsync #full { + pub attrs: Vec<Attribute>, + pub async_token: Token![async], + pub capture: Option<Token![move]>, + pub block: Block, + } +} + +ast_struct! { + /// An await expression: `fut.await`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprAwait #full { + pub attrs: Vec<Attribute>, + pub base: Box<Expr>, + pub dot_token: Token![.], + pub await_token: Token![await], + } +} + +ast_struct! { + /// A binary operation: `a + b`, `a += b`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprBinary { + pub attrs: Vec<Attribute>, + pub left: Box<Expr>, + pub op: BinOp, + pub right: Box<Expr>, + } +} + +ast_struct! { + /// A blocked scope: `{ ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprBlock #full { + pub attrs: Vec<Attribute>, + pub label: Option<Label>, + pub block: Block, + } +} + +ast_struct! { + /// A `break`, with an optional label to break and an optional + /// expression. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprBreak #full { + pub attrs: Vec<Attribute>, + pub break_token: Token![break], + pub label: Option<Lifetime>, + pub expr: Option<Box<Expr>>, + } +} + +ast_struct! { + /// A function call expression: `invoke(a, b)`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprCall { + pub attrs: Vec<Attribute>, + pub func: Box<Expr>, + pub paren_token: token::Paren, + pub args: Punctuated<Expr, Token![,]>, + } +} + +ast_struct! { + /// A cast expression: `foo as f64`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprCast { + pub attrs: Vec<Attribute>, + pub expr: Box<Expr>, + pub as_token: Token![as], + pub ty: Box<Type>, + } +} + +ast_struct! { + /// A closure expression: `|a, b| a + b`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprClosure #full { + pub attrs: Vec<Attribute>, + pub lifetimes: Option<BoundLifetimes>, + pub constness: Option<Token![const]>, + pub movability: Option<Token![static]>, + pub asyncness: Option<Token![async]>, + pub capture: Option<Token![move]>, + pub or1_token: Token![|], + pub inputs: Punctuated<Pat, Token![,]>, + pub or2_token: Token![|], + pub output: ReturnType, + pub body: Box<Expr>, + } +} + +ast_struct! { + /// A const block: `const { ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprConst #full { + pub attrs: Vec<Attribute>, + pub const_token: Token![const], + pub block: Block, + } +} + +ast_struct! { + /// A `continue`, with an optional label. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprContinue #full { + pub attrs: Vec<Attribute>, + pub continue_token: Token![continue], + pub label: Option<Lifetime>, + } +} + +ast_struct! { + /// Access of a named struct field (`obj.k`) or unnamed tuple struct + /// field (`obj.0`). + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprField { + pub attrs: Vec<Attribute>, + pub base: Box<Expr>, + pub dot_token: Token![.], + pub member: Member, + } +} + +ast_struct! { + /// A for loop: `for pat in expr { ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprForLoop #full { + pub attrs: Vec<Attribute>, + pub label: Option<Label>, + pub for_token: Token![for], + pub pat: Box<Pat>, + pub in_token: Token![in], + pub expr: Box<Expr>, + pub body: Block, + } +} + +ast_struct! { + /// An expression contained within invisible delimiters. + /// + /// This variant is important for faithfully representing the precedence + /// of expressions and is related to `None`-delimited spans in a + /// `TokenStream`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprGroup { + pub attrs: Vec<Attribute>, + pub group_token: token::Group, + pub expr: Box<Expr>, + } +} + +ast_struct! { + /// An `if` expression with an optional `else` block: `if expr { ... } + /// else { ... }`. + /// + /// The `else` branch expression may only be an `If` or `Block` + /// expression, not any of the other types of expression. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprIf #full { + pub attrs: Vec<Attribute>, + pub if_token: Token![if], + pub cond: Box<Expr>, + pub then_branch: Block, + pub else_branch: Option<(Token![else], Box<Expr>)>, + } +} + +ast_struct! { + /// A square bracketed indexing expression: `vector[2]`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprIndex { + pub attrs: Vec<Attribute>, + pub expr: Box<Expr>, + pub bracket_token: token::Bracket, + pub index: Box<Expr>, + } +} + +ast_struct! { + /// The inferred value of a const generic argument, denoted `_`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprInfer #full { + pub attrs: Vec<Attribute>, + pub underscore_token: Token![_], + } +} + +ast_struct! { + /// A `let` guard: `let Some(x) = opt`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprLet #full { + pub attrs: Vec<Attribute>, + pub let_token: Token![let], + pub pat: Box<Pat>, + pub eq_token: Token![=], + pub expr: Box<Expr>, + } +} + +ast_struct! { + /// A literal in place of an expression: `1`, `"foo"`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprLit { + pub attrs: Vec<Attribute>, + pub lit: Lit, + } +} + +ast_struct! { + /// Conditionless loop: `loop { ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprLoop #full { + pub attrs: Vec<Attribute>, + pub label: Option<Label>, + pub loop_token: Token![loop], + pub body: Block, + } +} + +ast_struct! { + /// A macro invocation expression: `format!("{}", q)`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprMacro { + pub attrs: Vec<Attribute>, + pub mac: Macro, + } +} + +ast_struct! { + /// A `match` expression: `match n { Some(n) => {}, None => {} }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprMatch #full { + pub attrs: Vec<Attribute>, + pub match_token: Token![match], + pub expr: Box<Expr>, + pub brace_token: token::Brace, + pub arms: Vec<Arm>, + } +} + +ast_struct! { + /// A method call expression: `x.foo::<T>(a, b)`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprMethodCall { + pub attrs: Vec<Attribute>, + pub receiver: Box<Expr>, + pub dot_token: Token![.], + pub method: Ident, + pub turbofish: Option<AngleBracketedGenericArguments>, + pub paren_token: token::Paren, + pub args: Punctuated<Expr, Token![,]>, + } +} + +ast_struct! { + /// A parenthesized expression: `(a + b)`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprParen { + pub attrs: Vec<Attribute>, + pub paren_token: token::Paren, + pub expr: Box<Expr>, + } +} + +ast_struct! { + /// A path like `std::mem::replace` possibly containing generic + /// parameters and a qualified self-type. + /// + /// A plain identifier like `x` is a path of length 1. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprPath { + pub attrs: Vec<Attribute>, + pub qself: Option<QSelf>, + pub path: Path, + } +} + +ast_struct! { + /// A range expression: `1..2`, `1..`, `..2`, `1..=2`, `..=2`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprRange #full { + pub attrs: Vec<Attribute>, + pub start: Option<Box<Expr>>, + pub limits: RangeLimits, + pub end: Option<Box<Expr>>, + } +} + +ast_struct! { + /// A referencing operation: `&a` or `&mut a`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprReference { + pub attrs: Vec<Attribute>, + pub and_token: Token![&], + pub mutability: Option<Token![mut]>, + pub expr: Box<Expr>, + } +} + +ast_struct! { + /// An array literal constructed from one repeated element: `[0u8; N]`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprRepeat #full { + pub attrs: Vec<Attribute>, + pub bracket_token: token::Bracket, + pub expr: Box<Expr>, + pub semi_token: Token![;], + pub len: Box<Expr>, + } +} + +ast_struct! { + /// A `return`, with an optional value to be returned. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprReturn #full { + pub attrs: Vec<Attribute>, + pub return_token: Token![return], + pub expr: Option<Box<Expr>>, + } +} + +ast_struct! { + /// A struct literal expression: `Point { x: 1, y: 1 }`. + /// + /// The `rest` provides the value of the remaining fields as in `S { a: + /// 1, b: 1, ..rest }`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprStruct { + pub attrs: Vec<Attribute>, + pub qself: Option<QSelf>, + pub path: Path, + pub brace_token: token::Brace, + pub fields: Punctuated<FieldValue, Token![,]>, + pub dot2_token: Option<Token![..]>, + pub rest: Option<Box<Expr>>, + } +} + +ast_struct! { + /// A try-expression: `expr?`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprTry #full { + pub attrs: Vec<Attribute>, + pub expr: Box<Expr>, + pub question_token: Token![?], + } +} + +ast_struct! { + /// A try block: `try { ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprTryBlock #full { + pub attrs: Vec<Attribute>, + pub try_token: Token![try], + pub block: Block, + } +} + +ast_struct! { + /// A tuple expression: `(a, b, c, d)`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprTuple #full { + pub attrs: Vec<Attribute>, + pub paren_token: token::Paren, + pub elems: Punctuated<Expr, Token![,]>, + } +} + +ast_struct! { + /// A unary operation: `!x`, `*x`. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct ExprUnary { + pub attrs: Vec<Attribute>, + pub op: UnOp, + pub expr: Box<Expr>, + } +} + +ast_struct! { + /// An unsafe block: `unsafe { ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprUnsafe #full { + pub attrs: Vec<Attribute>, + pub unsafe_token: Token![unsafe], + pub block: Block, + } +} + +ast_struct! { + /// A while loop: `while expr { ... }`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprWhile #full { + pub attrs: Vec<Attribute>, + pub label: Option<Label>, + pub while_token: Token![while], + pub cond: Box<Expr>, + pub body: Block, + } +} + +ast_struct! { + /// A yield expression: `yield expr`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct ExprYield #full { + pub attrs: Vec<Attribute>, + pub yield_token: Token![yield], + pub expr: Option<Box<Expr>>, + } +} + +impl Expr { + #[cfg(feature = "parsing")] + const DUMMY: Self = Expr::Path(ExprPath { + attrs: Vec::new(), + qself: None, + path: Path { + leading_colon: None, + segments: Punctuated::new(), + }, + }); + + #[cfg(all(feature = "parsing", feature = "full"))] + pub(crate) fn replace_attrs(&mut self, new: Vec<Attribute>) -> Vec<Attribute> { + match self { + Expr::Array(ExprArray { attrs, .. }) + | Expr::Assign(ExprAssign { attrs, .. }) + | Expr::Async(ExprAsync { attrs, .. }) + | Expr::Await(ExprAwait { attrs, .. }) + | Expr::Binary(ExprBinary { attrs, .. }) + | Expr::Block(ExprBlock { attrs, .. }) + | Expr::Break(ExprBreak { attrs, .. }) + | Expr::Call(ExprCall { attrs, .. }) + | Expr::Cast(ExprCast { attrs, .. }) + | Expr::Closure(ExprClosure { attrs, .. }) + | Expr::Const(ExprConst { attrs, .. }) + | Expr::Continue(ExprContinue { attrs, .. }) + | Expr::Field(ExprField { attrs, .. }) + | Expr::ForLoop(ExprForLoop { attrs, .. }) + | Expr::Group(ExprGroup { attrs, .. }) + | Expr::If(ExprIf { attrs, .. }) + | Expr::Index(ExprIndex { attrs, .. }) + | Expr::Infer(ExprInfer { attrs, .. }) + | Expr::Let(ExprLet { attrs, .. }) + | Expr::Lit(ExprLit { attrs, .. }) + | Expr::Loop(ExprLoop { attrs, .. }) + | Expr::Macro(ExprMacro { attrs, .. }) + | Expr::Match(ExprMatch { attrs, .. }) + | Expr::MethodCall(ExprMethodCall { attrs, .. }) + | Expr::Paren(ExprParen { attrs, .. }) + | Expr::Path(ExprPath { attrs, .. }) + | Expr::Range(ExprRange { attrs, .. }) + | Expr::Reference(ExprReference { attrs, .. }) + | Expr::Repeat(ExprRepeat { attrs, .. }) + | Expr::Return(ExprReturn { attrs, .. }) + | Expr::Struct(ExprStruct { attrs, .. }) + | Expr::Try(ExprTry { attrs, .. }) + | Expr::TryBlock(ExprTryBlock { attrs, .. }) + | Expr::Tuple(ExprTuple { attrs, .. }) + | Expr::Unary(ExprUnary { attrs, .. }) + | Expr::Unsafe(ExprUnsafe { attrs, .. }) + | Expr::While(ExprWhile { attrs, .. }) + | Expr::Yield(ExprYield { attrs, .. }) => mem::replace(attrs, new), + Expr::Verbatim(_) => Vec::new(), + } + } +} + +ast_enum! { + /// A struct or tuple struct field accessed in a struct literal or field + /// expression. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub enum Member { + /// A named field like `self.x`. + Named(Ident), + /// An unnamed field like `self.0`. + Unnamed(Index), + } +} + +impl From<Ident> for Member { + fn from(ident: Ident) -> Member { + Member::Named(ident) + } +} + +impl From<Index> for Member { + fn from(index: Index) -> Member { + Member::Unnamed(index) + } +} + +impl From<usize> for Member { + fn from(index: usize) -> Member { + Member::Unnamed(Index::from(index)) + } +} + +impl Eq for Member {} + +impl PartialEq for Member { + fn eq(&self, other: &Self) -> bool { + match (self, other) { + (Member::Named(this), Member::Named(other)) => this == other, + (Member::Unnamed(this), Member::Unnamed(other)) => this == other, + _ => false, + } + } +} + +impl Hash for Member { + fn hash<H: Hasher>(&self, state: &mut H) { + match self { + Member::Named(m) => m.hash(state), + Member::Unnamed(m) => m.hash(state), + } + } +} + +#[cfg(feature = "printing")] +impl IdentFragment for Member { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + match self { + Member::Named(m) => Display::fmt(m, formatter), + Member::Unnamed(m) => Display::fmt(&m.index, formatter), + } + } + + fn span(&self) -> Option<Span> { + match self { + Member::Named(m) => Some(m.span()), + Member::Unnamed(m) => Some(m.span), + } + } +} + +ast_struct! { + /// The index of an unnamed tuple struct field. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct Index { + pub index: u32, + pub span: Span, + } +} + +impl From<usize> for Index { + fn from(index: usize) -> Index { + assert!(index < u32::max_value() as usize); + Index { + index: index as u32, + span: Span::call_site(), + } + } +} + +impl Eq for Index {} + +impl PartialEq for Index { + fn eq(&self, other: &Self) -> bool { + self.index == other.index + } +} + +impl Hash for Index { + fn hash<H: Hasher>(&self, state: &mut H) { + self.index.hash(state); + } +} + +#[cfg(feature = "printing")] +impl IdentFragment for Index { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + Display::fmt(&self.index, formatter) + } + + fn span(&self) -> Option<Span> { + Some(self.span) + } +} + +ast_struct! { + /// A field-value pair in a struct literal. + #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))] + pub struct FieldValue { + pub attrs: Vec<Attribute>, + pub member: Member, + + /// The colon in `Struct { x: x }`. If written in shorthand like + /// `Struct { x }`, there is no colon. + pub colon_token: Option<Token![:]>, + + pub expr: Expr, + } +} + +#[cfg(feature = "full")] +ast_struct! { + /// A lifetime labeling a `for`, `while`, or `loop`. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct Label { + pub name: Lifetime, + pub colon_token: Token![:], + } +} + +#[cfg(feature = "full")] +ast_struct! { + /// One arm of a `match` expression: `0..=10 => { return true; }`. + /// + /// As in: + /// + /// ``` + /// # fn f() -> bool { + /// # let n = 0; + /// match n { + /// 0..=10 => { + /// return true; + /// } + /// // ... + /// # _ => {} + /// } + /// # false + /// # } + /// ``` + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub struct Arm { + pub attrs: Vec<Attribute>, + pub pat: Pat, + pub guard: Option<(Token![if], Box<Expr>)>, + pub fat_arrow_token: Token![=>], + pub body: Box<Expr>, + pub comma: Option<Token![,]>, + } +} + +#[cfg(feature = "full")] +ast_enum! { + /// Limit types of a range, inclusive or exclusive. + #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))] + pub enum RangeLimits { + /// Inclusive at the beginning, exclusive at the end. + HalfOpen(Token![..]), + /// Inclusive at the beginning and end. + Closed(Token![..=]), + } +} + +#[cfg(any(feature = "parsing", feature = "printing"))] +#[cfg(feature = "full")] +pub(crate) fn requires_terminator(expr: &Expr) -> bool { + // see https://github.com/rust-lang/rust/blob/9a19e7604/compiler/rustc_ast/src/util/classify.rs#L7-L26 + match expr { + Expr::If(_) + | Expr::Match(_) + | Expr::Block(_) | Expr::Unsafe(_) // both under ExprKind::Block in rustc + | Expr::While(_) + | Expr::Loop(_) + | Expr::ForLoop(_) + | Expr::TryBlock(_) + | Expr::Const(_) => false, + Expr::Array(_) + | Expr::Assign(_) + | Expr::Async(_) + | Expr::Await(_) + | Expr::Binary(_) + | Expr::Break(_) + | Expr::Call(_) + | Expr::Cast(_) + | Expr::Closure(_) + | Expr::Continue(_) + | Expr::Field(_) + | Expr::Group(_) + | Expr::Index(_) + | Expr::Infer(_) + | Expr::Let(_) + | Expr::Lit(_) + | Expr::Macro(_) + | Expr::MethodCall(_) + | Expr::Paren(_) + | Expr::Path(_) + | Expr::Range(_) + | Expr::Reference(_) + | Expr::Repeat(_) + | Expr::Return(_) + | Expr::Struct(_) + | Expr::Try(_) + | Expr::Tuple(_) + | Expr::Unary(_) + | Expr::Yield(_) + | Expr::Verbatim(_) => true + } +} + +#[cfg(feature = "parsing")] +mod precedence { + use super::BinOp; + + pub(crate) enum Precedence { + Any, + Assign, + Range, + Or, + And, + Compare, + BitOr, + BitXor, + BitAnd, + Shift, + Arithmetic, + Term, + Cast, + } + + impl Precedence { + pub(crate) fn of(op: &BinOp) -> Self { + match op { + BinOp::Add(_) | BinOp::Sub(_) => Precedence::Arithmetic, + BinOp::Mul(_) | BinOp::Div(_) | BinOp::Rem(_) => Precedence::Term, + BinOp::And(_) => Precedence::And, + BinOp::Or(_) => Precedence::Or, + BinOp::BitXor(_) => Precedence::BitXor, + BinOp::BitAnd(_) => Precedence::BitAnd, + BinOp::BitOr(_) => Precedence::BitOr, + BinOp::Shl(_) | BinOp::Shr(_) => Precedence::Shift, + BinOp::Eq(_) + | BinOp::Lt(_) + | BinOp::Le(_) + | BinOp::Ne(_) + | BinOp::Ge(_) + | BinOp::Gt(_) => Precedence::Compare, + BinOp::AddAssign(_) + | BinOp::SubAssign(_) + | BinOp::MulAssign(_) + | BinOp::DivAssign(_) + | BinOp::RemAssign(_) + | BinOp::BitXorAssign(_) + | BinOp::BitAndAssign(_) + | BinOp::BitOrAssign(_) + | BinOp::ShlAssign(_) + | BinOp::ShrAssign(_) => Precedence::Assign, + } + } + } +} + +#[cfg(feature = "parsing")] +pub(crate) mod parsing { + use super::precedence::Precedence; + use super::*; + #[cfg(feature = "full")] + use crate::ext::IdentExt as _; + use crate::parse::discouraged::Speculative as _; + #[cfg(feature = "full")] + use crate::parse::ParseBuffer; + use crate::parse::{Parse, ParseStream, Result}; + use crate::path; + use std::cmp::Ordering; + + mod kw { + crate::custom_keyword!(builtin); + crate::custom_keyword!(raw); + } + + // When we're parsing expressions which occur before blocks, like in an if + // statement's condition, we cannot parse a struct literal. + // + // Struct literals are ambiguous in certain positions + // https://github.com/rust-lang/rfcs/pull/92 + #[cfg(feature = "full")] + pub(crate) struct AllowStruct(bool); + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for Expr { + fn parse(input: ParseStream) -> Result<Self> { + ambiguous_expr( + input, + #[cfg(feature = "full")] + AllowStruct(true), + ) + } + } + + impl Expr { + /// An alternative to the primary `Expr::parse` parser (from the + /// [`Parse`] trait) for ambiguous syntactic positions in which a + /// trailing brace should not be taken as part of the expression. + /// + /// Rust grammar has an ambiguity where braces sometimes turn a path + /// expression into a struct initialization and sometimes do not. In the + /// following code, the expression `S {}` is one expression. Presumably + /// there is an empty struct `struct S {}` defined somewhere which it is + /// instantiating. + /// + /// ``` + /// # struct S; + /// # impl std::ops::Deref for S { + /// # type Target = bool; + /// # fn deref(&self) -> &Self::Target { + /// # &true + /// # } + /// # } + /// let _ = *S {}; + /// + /// // parsed by rustc as: `*(S {})` + /// ``` + /// + /// We would want to parse the above using `Expr::parse` after the `=` + /// token. + /// + /// But in the following, `S {}` is *not* a struct init expression. + /// + /// ``` + /// # const S: &bool = &true; + /// if *S {} {} + /// + /// // parsed by rustc as: + /// // + /// // if (*S) { + /// // /* empty block */ + /// // } + /// // { + /// // /* another empty block */ + /// // } + /// ``` + /// + /// For that reason we would want to parse if-conditions using + /// `Expr::parse_without_eager_brace` after the `if` token. Same for + /// similar syntactic positions such as the condition expr after a + /// `while` token or the expr at the top of a `match`. + /// + /// The Rust grammar's choices around which way this ambiguity is + /// resolved at various syntactic positions is fairly arbitrary. Really + /// either parse behavior could work in most positions, and language + /// designers just decide each case based on which is more likely to be + /// what the programmer had in mind most of the time. + /// + /// ``` + /// # struct S; + /// # fn doc() -> S { + /// if return S {} {} + /// # unreachable!() + /// # } + /// + /// // parsed by rustc as: + /// // + /// // if (return (S {})) { + /// // } + /// // + /// // but could equally well have been this other arbitrary choice: + /// // + /// // if (return S) { + /// // } + /// // {} + /// ``` + /// + /// Note the grammar ambiguity on trailing braces is distinct from + /// precedence and is not captured by assigning a precedence level to + /// the braced struct init expr in relation to other operators. This can + /// be illustrated by `return 0..S {}` vs `match 0..S {}`. The former + /// parses as `return (0..(S {}))` implying tighter precedence for + /// struct init than `..`, while the latter parses as `match (0..S) {}` + /// implying tighter precedence for `..` than struct init, a + /// contradiction. + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(all(feature = "full", feature = "parsing"))))] + pub fn parse_without_eager_brace(input: ParseStream) -> Result<Expr> { + ambiguous_expr(input, AllowStruct(false)) + } + } + + #[cfg(feature = "full")] + impl Copy for AllowStruct {} + + #[cfg(feature = "full")] + impl Clone for AllowStruct { + fn clone(&self) -> Self { + *self + } + } + + impl Copy for Precedence {} + + impl Clone for Precedence { + fn clone(&self) -> Self { + *self + } + } + + impl PartialEq for Precedence { + fn eq(&self, other: &Self) -> bool { + *self as u8 == *other as u8 + } + } + + impl PartialOrd for Precedence { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + let this = *self as u8; + let other = *other as u8; + Some(this.cmp(&other)) + } + } + + #[cfg(feature = "full")] + fn can_begin_expr(input: ParseStream) -> bool { + input.peek(Ident::peek_any) // value name or keyword + || input.peek(token::Paren) // tuple + || input.peek(token::Bracket) // array + || input.peek(token::Brace) // block + || input.peek(Lit) // literal + || input.peek(Token![!]) && !input.peek(Token![!=]) // operator not + || input.peek(Token![-]) && !input.peek(Token![-=]) && !input.peek(Token![->]) // unary minus + || input.peek(Token![*]) && !input.peek(Token![*=]) // dereference + || input.peek(Token![|]) && !input.peek(Token![|=]) // closure + || input.peek(Token![&]) && !input.peek(Token![&=]) // reference + || input.peek(Token![..]) // range notation + || input.peek(Token![<]) && !input.peek(Token![<=]) && !input.peek(Token![<<=]) // associated path + || input.peek(Token![::]) // global path + || input.peek(Lifetime) // labeled loop + || input.peek(Token![#]) // expression attributes + } + + #[cfg(feature = "full")] + fn parse_expr( + input: ParseStream, + mut lhs: Expr, + allow_struct: AllowStruct, + base: Precedence, + ) -> Result<Expr> { + loop { + let ahead = input.fork(); + if let Some(op) = match ahead.parse::<BinOp>() { + Ok(op) if Precedence::of(&op) >= base => Some(op), + _ => None, + } { + input.advance_to(&ahead); + let precedence = Precedence::of(&op); + let mut rhs = unary_expr(input, allow_struct)?; + loop { + let next = peek_precedence(input); + if next > precedence || next == precedence && precedence == Precedence::Assign { + rhs = parse_expr(input, rhs, allow_struct, next)?; + } else { + break; + } + } + lhs = Expr::Binary(ExprBinary { + attrs: Vec::new(), + left: Box::new(lhs), + op, + right: Box::new(rhs), + }); + } else if Precedence::Assign >= base + && input.peek(Token![=]) + && !input.peek(Token![==]) + && !input.peek(Token![=>]) + { + let eq_token: Token![=] = input.parse()?; + let mut rhs = unary_expr(input, allow_struct)?; + loop { + let next = peek_precedence(input); + if next >= Precedence::Assign { + rhs = parse_expr(input, rhs, allow_struct, next)?; + } else { + break; + } + } + lhs = Expr::Assign(ExprAssign { + attrs: Vec::new(), + left: Box::new(lhs), + eq_token, + right: Box::new(rhs), + }); + } else if Precedence::Range >= base && input.peek(Token![..]) { + let limits: RangeLimits = input.parse()?; + let rhs = if matches!(limits, RangeLimits::HalfOpen(_)) + && (input.is_empty() + || input.peek(Token![,]) + || input.peek(Token![;]) + || input.peek(Token![.]) && !input.peek(Token![..]) + || !allow_struct.0 && input.peek(token::Brace)) + { + None + } else { + let mut rhs = unary_expr(input, allow_struct)?; + loop { + let next = peek_precedence(input); + if next > Precedence::Range { + rhs = parse_expr(input, rhs, allow_struct, next)?; + } else { + break; + } + } + Some(rhs) + }; + lhs = Expr::Range(ExprRange { + attrs: Vec::new(), + start: Some(Box::new(lhs)), + limits, + end: rhs.map(Box::new), + }); + } else if Precedence::Cast >= base && input.peek(Token![as]) { + let as_token: Token![as] = input.parse()?; + let allow_plus = false; + let allow_group_generic = false; + let ty = ty::parsing::ambig_ty(input, allow_plus, allow_group_generic)?; + check_cast(input)?; + lhs = Expr::Cast(ExprCast { + attrs: Vec::new(), + expr: Box::new(lhs), + as_token, + ty: Box::new(ty), + }); + } else { + break; + } + } + Ok(lhs) + } + + #[cfg(not(feature = "full"))] + fn parse_expr(input: ParseStream, mut lhs: Expr, base: Precedence) -> Result<Expr> { + loop { + let ahead = input.fork(); + if let Some(op) = match ahead.parse::<BinOp>() { + Ok(op) if Precedence::of(&op) >= base => Some(op), + _ => None, + } { + input.advance_to(&ahead); + let precedence = Precedence::of(&op); + let mut rhs = unary_expr(input)?; + loop { + let next = peek_precedence(input); + if next > precedence || next == precedence && precedence == Precedence::Assign { + rhs = parse_expr(input, rhs, next)?; + } else { + break; + } + } + lhs = Expr::Binary(ExprBinary { + attrs: Vec::new(), + left: Box::new(lhs), + op, + right: Box::new(rhs), + }); + } else if Precedence::Cast >= base && input.peek(Token![as]) { + let as_token: Token![as] = input.parse()?; + let allow_plus = false; + let allow_group_generic = false; + let ty = ty::parsing::ambig_ty(input, allow_plus, allow_group_generic)?; + check_cast(input)?; + lhs = Expr::Cast(ExprCast { + attrs: Vec::new(), + expr: Box::new(lhs), + as_token, + ty: Box::new(ty), + }); + } else { + break; + } + } + Ok(lhs) + } + + fn peek_precedence(input: ParseStream) -> Precedence { + if let Ok(op) = input.fork().parse() { + Precedence::of(&op) + } else if input.peek(Token![=]) && !input.peek(Token![=>]) { + Precedence::Assign + } else if input.peek(Token![..]) { + Precedence::Range + } else if input.peek(Token![as]) { + Precedence::Cast + } else { + Precedence::Any + } + } + + // Parse an arbitrary expression. + fn ambiguous_expr( + input: ParseStream, + #[cfg(feature = "full")] allow_struct: AllowStruct, + ) -> Result<Expr> { + let lhs = unary_expr( + input, + #[cfg(feature = "full")] + allow_struct, + )?; + parse_expr( + input, + lhs, + #[cfg(feature = "full")] + allow_struct, + Precedence::Any, + ) + } + + #[cfg(feature = "full")] + fn expr_attrs(input: ParseStream) -> Result<Vec<Attribute>> { + let mut attrs = Vec::new(); + while !input.peek(token::Group) && input.peek(Token![#]) { + attrs.push(input.call(attr::parsing::single_parse_outer)?); + } + Ok(attrs) + } + + // <UnOp> <trailer> + // & <trailer> + // &mut <trailer> + // box <trailer> + #[cfg(feature = "full")] + fn unary_expr(input: ParseStream, allow_struct: AllowStruct) -> Result<Expr> { + let begin = input.fork(); + let attrs = input.call(expr_attrs)?; + if input.peek(token::Group) { + return trailer_expr(begin, attrs, input, allow_struct); + } + + if input.peek(Token![&]) { + let and_token: Token![&] = input.parse()?; + let raw: Option<kw::raw> = if input.peek(kw::raw) + && (input.peek2(Token![mut]) || input.peek2(Token![const])) + { + Some(input.parse()?) + } else { + None + }; + let mutability: Option<Token![mut]> = input.parse()?; + if raw.is_some() && mutability.is_none() { + input.parse::<Token![const]>()?; + } + let expr = Box::new(unary_expr(input, allow_struct)?); + if raw.is_some() { + Ok(Expr::Verbatim(verbatim::between(&begin, input))) + } else { + Ok(Expr::Reference(ExprReference { + attrs, + and_token, + mutability, + expr, + })) + } + } else if input.peek(Token![*]) || input.peek(Token![!]) || input.peek(Token![-]) { + expr_unary(input, attrs, allow_struct).map(Expr::Unary) + } else { + trailer_expr(begin, attrs, input, allow_struct) + } + } + + #[cfg(not(feature = "full"))] + fn unary_expr(input: ParseStream) -> Result<Expr> { + if input.peek(Token![&]) { + Ok(Expr::Reference(ExprReference { + attrs: Vec::new(), + and_token: input.parse()?, + mutability: input.parse()?, + expr: Box::new(unary_expr(input)?), + })) + } else if input.peek(Token![*]) || input.peek(Token![!]) || input.peek(Token![-]) { + Ok(Expr::Unary(ExprUnary { + attrs: Vec::new(), + op: input.parse()?, + expr: Box::new(unary_expr(input)?), + })) + } else { + trailer_expr(input) + } + } + + // <atom> (..<args>) ... + // <atom> . <ident> (..<args>) ... + // <atom> . <ident> ... + // <atom> . <lit> ... + // <atom> [ <expr> ] ... + // <atom> ? ... + #[cfg(feature = "full")] + fn trailer_expr( + begin: ParseBuffer, + mut attrs: Vec<Attribute>, + input: ParseStream, + allow_struct: AllowStruct, + ) -> Result<Expr> { + let atom = atom_expr(input, allow_struct)?; + let mut e = trailer_helper(input, atom)?; + + if let Expr::Verbatim(tokens) = &mut e { + *tokens = verbatim::between(&begin, input); + } else { + let inner_attrs = e.replace_attrs(Vec::new()); + attrs.extend(inner_attrs); + e.replace_attrs(attrs); + } + + Ok(e) + } + + #[cfg(feature = "full")] + fn trailer_helper(input: ParseStream, mut e: Expr) -> Result<Expr> { + loop { + if input.peek(token::Paren) { + let content; + e = Expr::Call(ExprCall { + attrs: Vec::new(), + func: Box::new(e), + paren_token: parenthesized!(content in input), + args: content.parse_terminated(Expr::parse, Token![,])?, + }); + } else if input.peek(Token![.]) + && !input.peek(Token![..]) + && match e { + Expr::Range(_) => false, + _ => true, + } + { + let mut dot_token: Token![.] = input.parse()?; + + let float_token: Option<LitFloat> = input.parse()?; + if let Some(float_token) = float_token { + if multi_index(&mut e, &mut dot_token, float_token)? { + continue; + } + } + + let await_token: Option<Token![await]> = input.parse()?; + if let Some(await_token) = await_token { + e = Expr::Await(ExprAwait { + attrs: Vec::new(), + base: Box::new(e), + dot_token, + await_token, + }); + continue; + } + + let member: Member = input.parse()?; + let turbofish = if member.is_named() && input.peek(Token![::]) { + Some(AngleBracketedGenericArguments::parse_turbofish(input)?) + } else { + None + }; + + if turbofish.is_some() || input.peek(token::Paren) { + if let Member::Named(method) = member { + let content; + e = Expr::MethodCall(ExprMethodCall { + attrs: Vec::new(), + receiver: Box::new(e), + dot_token, + method, + turbofish, + paren_token: parenthesized!(content in input), + args: content.parse_terminated(Expr::parse, Token![,])?, + }); + continue; + } + } + + e = Expr::Field(ExprField { + attrs: Vec::new(), + base: Box::new(e), + dot_token, + member, + }); + } else if input.peek(token::Bracket) { + let content; + e = Expr::Index(ExprIndex { + attrs: Vec::new(), + expr: Box::new(e), + bracket_token: bracketed!(content in input), + index: content.parse()?, + }); + } else if input.peek(Token![?]) { + e = Expr::Try(ExprTry { + attrs: Vec::new(), + expr: Box::new(e), + question_token: input.parse()?, + }); + } else { + break; + } + } + Ok(e) + } + + #[cfg(not(feature = "full"))] + fn trailer_expr(input: ParseStream) -> Result<Expr> { + let mut e = atom_expr(input)?; + + loop { + if input.peek(token::Paren) { + let content; + e = Expr::Call(ExprCall { + attrs: Vec::new(), + func: Box::new(e), + paren_token: parenthesized!(content in input), + args: content.parse_terminated(Expr::parse, Token![,])?, + }); + } else if input.peek(Token![.]) + && !input.peek(Token![..]) + && !input.peek2(Token![await]) + { + let mut dot_token: Token![.] = input.parse()?; + + let float_token: Option<LitFloat> = input.parse()?; + if let Some(float_token) = float_token { + if multi_index(&mut e, &mut dot_token, float_token)? { + continue; + } + } + + let member: Member = input.parse()?; + let turbofish = if member.is_named() && input.peek(Token![::]) { + let colon2_token: Token![::] = input.parse()?; + let turbofish = + AngleBracketedGenericArguments::do_parse(Some(colon2_token), input)?; + Some(turbofish) + } else { + None + }; + + if turbofish.is_some() || input.peek(token::Paren) { + if let Member::Named(method) = member { + let content; + e = Expr::MethodCall(ExprMethodCall { + attrs: Vec::new(), + receiver: Box::new(e), + dot_token, + method, + turbofish, + paren_token: parenthesized!(content in input), + args: content.parse_terminated(Expr::parse, Token![,])?, + }); + continue; + } + } + + e = Expr::Field(ExprField { + attrs: Vec::new(), + base: Box::new(e), + dot_token, + member, + }); + } else if input.peek(token::Bracket) { + let content; + e = Expr::Index(ExprIndex { + attrs: Vec::new(), + expr: Box::new(e), + bracket_token: bracketed!(content in input), + index: content.parse()?, + }); + } else { + break; + } + } + + Ok(e) + } + + // Parse all atomic expressions which don't have to worry about precedence + // interactions, as they are fully contained. + #[cfg(feature = "full")] + fn atom_expr(input: ParseStream, allow_struct: AllowStruct) -> Result<Expr> { + if input.peek(token::Group) { + expr_group(input, allow_struct) + } else if input.peek(Lit) { + input.parse().map(Expr::Lit) + } else if input.peek(Token![async]) + && (input.peek2(token::Brace) || input.peek2(Token![move]) && input.peek3(token::Brace)) + { + input.parse().map(Expr::Async) + } else if input.peek(Token![try]) && input.peek2(token::Brace) { + input.parse().map(Expr::TryBlock) + } else if input.peek(Token![|]) + || input.peek(Token![move]) + || input.peek(Token![for]) + && input.peek2(Token![<]) + && (input.peek3(Lifetime) || input.peek3(Token![>])) + || input.peek(Token![const]) && !input.peek2(token::Brace) + || input.peek(Token![static]) + || input.peek(Token![async]) && (input.peek2(Token![|]) || input.peek2(Token![move])) + { + expr_closure(input, allow_struct).map(Expr::Closure) + } else if input.peek(kw::builtin) && input.peek2(Token![#]) { + expr_builtin(input) + } else if input.peek(Ident) + || input.peek(Token![::]) + || input.peek(Token![<]) + || input.peek(Token![self]) + || input.peek(Token![Self]) + || input.peek(Token![super]) + || input.peek(Token![crate]) + || input.peek(Token![try]) && (input.peek2(Token![!]) || input.peek2(Token![::])) + { + path_or_macro_or_struct(input, allow_struct) + } else if input.peek(token::Paren) { + paren_or_tuple(input) + } else if input.peek(Token![break]) { + expr_break(input, allow_struct).map(Expr::Break) + } else if input.peek(Token![continue]) { + input.parse().map(Expr::Continue) + } else if input.peek(Token![return]) { + expr_return(input, allow_struct).map(Expr::Return) + } else if input.peek(token::Bracket) { + array_or_repeat(input) + } else if input.peek(Token![let]) { + input.parse().map(Expr::Let) + } else if input.peek(Token![if]) { + input.parse().map(Expr::If) + } else if input.peek(Token![while]) { + input.parse().map(Expr::While) + } else if input.peek(Token![for]) { + input.parse().map(Expr::ForLoop) + } else if input.peek(Token![loop]) { + input.parse().map(Expr::Loop) + } else if input.peek(Token![match]) { + input.parse().map(Expr::Match) + } else if input.peek(Token![yield]) { + input.parse().map(Expr::Yield) + } else if input.peek(Token![unsafe]) { + input.parse().map(Expr::Unsafe) + } else if input.peek(Token![const]) { + input.parse().map(Expr::Const) + } else if input.peek(token::Brace) { + input.parse().map(Expr::Block) + } else if input.peek(Token![..]) { + expr_range(input, allow_struct).map(Expr::Range) + } else if input.peek(Token![_]) { + input.parse().map(Expr::Infer) + } else if input.peek(Lifetime) { + atom_labeled(input) + } else { + Err(input.error("expected an expression")) + } + } + + #[cfg(feature = "full")] + fn atom_labeled(input: ParseStream) -> Result<Expr> { + let the_label: Label = input.parse()?; + let mut expr = if input.peek(Token![while]) { + Expr::While(input.parse()?) + } else if input.peek(Token![for]) { + Expr::ForLoop(input.parse()?) + } else if input.peek(Token![loop]) { + Expr::Loop(input.parse()?) + } else if input.peek(token::Brace) { + Expr::Block(input.parse()?) + } else { + return Err(input.error("expected loop or block expression")); + }; + match &mut expr { + Expr::While(ExprWhile { label, .. }) + | Expr::ForLoop(ExprForLoop { label, .. }) + | Expr::Loop(ExprLoop { label, .. }) + | Expr::Block(ExprBlock { label, .. }) => *label = Some(the_label), + _ => unreachable!(), + } + Ok(expr) + } + + #[cfg(not(feature = "full"))] + fn atom_expr(input: ParseStream) -> Result<Expr> { + if input.peek(token::Group) { + expr_group(input) + } else if input.peek(Lit) { + input.parse().map(Expr::Lit) + } else if input.peek(token::Paren) { + input.call(expr_paren).map(Expr::Paren) + } else if input.peek(Ident) + || input.peek(Token![::]) + || input.peek(Token![<]) + || input.peek(Token![self]) + || input.peek(Token![Self]) + || input.peek(Token![super]) + || input.peek(Token![crate]) + { + path_or_macro_or_struct(input) + } else if input.is_empty() { + Err(input.error("expected an expression")) + } else { + if input.peek(token::Brace) { + let scan = input.fork(); + let content; + braced!(content in scan); + if content.parse::<Expr>().is_ok() && content.is_empty() { + let expr_block = verbatim::between(input, &scan); + input.advance_to(&scan); + return Ok(Expr::Verbatim(expr_block)); + } + } + Err(input.error("unsupported expression; enable syn's features=[\"full\"]")) + } + } + + #[cfg(feature = "full")] + fn expr_builtin(input: ParseStream) -> Result<Expr> { + let begin = input.fork(); + + input.parse::<kw::builtin>()?; + input.parse::<Token![#]>()?; + input.parse::<Ident>()?; + + let args; + parenthesized!(args in input); + args.parse::<TokenStream>()?; + + Ok(Expr::Verbatim(verbatim::between(&begin, input))) + } + + fn path_or_macro_or_struct( + input: ParseStream, + #[cfg(feature = "full")] allow_struct: AllowStruct, + ) -> Result<Expr> { + let (qself, path) = path::parsing::qpath(input, true)?; + rest_of_path_or_macro_or_struct( + qself, + path, + input, + #[cfg(feature = "full")] + allow_struct, + ) + } + + fn rest_of_path_or_macro_or_struct( + qself: Option<QSelf>, + path: Path, + input: ParseStream, + #[cfg(feature = "full")] allow_struct: AllowStruct, + ) -> Result<Expr> { + if qself.is_none() + && input.peek(Token![!]) + && !input.peek(Token![!=]) + && path.is_mod_style() + { + let bang_token: Token![!] = input.parse()?; + let (delimiter, tokens) = mac::parse_delimiter(input)?; + return Ok(Expr::Macro(ExprMacro { + attrs: Vec::new(), + mac: Macro { + path, + bang_token, + delimiter, + tokens, + }, + })); + } + + #[cfg(not(feature = "full"))] + let allow_struct = (true,); + if allow_struct.0 && input.peek(token::Brace) { + return expr_struct_helper(input, qself, path).map(Expr::Struct); + } + + Ok(Expr::Path(ExprPath { + attrs: Vec::new(), + qself, + path, + })) + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprMacro { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprMacro { + attrs: Vec::new(), + mac: input.parse()?, + }) + } + } + + #[cfg(feature = "full")] + fn paren_or_tuple(input: ParseStream) -> Result<Expr> { + let content; + let paren_token = parenthesized!(content in input); + if content.is_empty() { + return Ok(Expr::Tuple(ExprTuple { + attrs: Vec::new(), + paren_token, + elems: Punctuated::new(), + })); + } + + let first: Expr = content.parse()?; + if content.is_empty() { + return Ok(Expr::Paren(ExprParen { + attrs: Vec::new(), + paren_token, + expr: Box::new(first), + })); + } + + let mut elems = Punctuated::new(); + elems.push_value(first); + while !content.is_empty() { + let punct = content.parse()?; + elems.push_punct(punct); + if content.is_empty() { + break; + } + let value = content.parse()?; + elems.push_value(value); + } + Ok(Expr::Tuple(ExprTuple { + attrs: Vec::new(), + paren_token, + elems, + })) + } + + #[cfg(feature = "full")] + fn array_or_repeat(input: ParseStream) -> Result<Expr> { + let content; + let bracket_token = bracketed!(content in input); + if content.is_empty() { + return Ok(Expr::Array(ExprArray { + attrs: Vec::new(), + bracket_token, + elems: Punctuated::new(), + })); + } + + let first: Expr = content.parse()?; + if content.is_empty() || content.peek(Token![,]) { + let mut elems = Punctuated::new(); + elems.push_value(first); + while !content.is_empty() { + let punct = content.parse()?; + elems.push_punct(punct); + if content.is_empty() { + break; + } + let value = content.parse()?; + elems.push_value(value); + } + Ok(Expr::Array(ExprArray { + attrs: Vec::new(), + bracket_token, + elems, + })) + } else if content.peek(Token![;]) { + let semi_token: Token![;] = content.parse()?; + let len: Expr = content.parse()?; + Ok(Expr::Repeat(ExprRepeat { + attrs: Vec::new(), + bracket_token, + expr: Box::new(first), + semi_token, + len: Box::new(len), + })) + } else { + Err(content.error("expected `,` or `;`")) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprArray { + fn parse(input: ParseStream) -> Result<Self> { + let content; + let bracket_token = bracketed!(content in input); + let mut elems = Punctuated::new(); + + while !content.is_empty() { + let first: Expr = content.parse()?; + elems.push_value(first); + if content.is_empty() { + break; + } + let punct = content.parse()?; + elems.push_punct(punct); + } + + Ok(ExprArray { + attrs: Vec::new(), + bracket_token, + elems, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprRepeat { + fn parse(input: ParseStream) -> Result<Self> { + let content; + Ok(ExprRepeat { + bracket_token: bracketed!(content in input), + attrs: Vec::new(), + expr: content.parse()?, + semi_token: content.parse()?, + len: content.parse()?, + }) + } + } + + #[cfg(feature = "full")] + pub(crate) fn expr_early(input: ParseStream) -> Result<Expr> { + let mut attrs = input.call(expr_attrs)?; + let mut expr = if input.peek(token::Group) { + let allow_struct = AllowStruct(true); + let atom = expr_group(input, allow_struct)?; + if continue_parsing_early(&atom) { + trailer_helper(input, atom)? + } else { + atom + } + } else if input.peek(Token![if]) { + Expr::If(input.parse()?) + } else if input.peek(Token![while]) { + Expr::While(input.parse()?) + } else if input.peek(Token![for]) + && !(input.peek2(Token![<]) && (input.peek3(Lifetime) || input.peek3(Token![>]))) + { + Expr::ForLoop(input.parse()?) + } else if input.peek(Token![loop]) { + Expr::Loop(input.parse()?) + } else if input.peek(Token![match]) { + Expr::Match(input.parse()?) + } else if input.peek(Token![try]) && input.peek2(token::Brace) { + Expr::TryBlock(input.parse()?) + } else if input.peek(Token![unsafe]) { + Expr::Unsafe(input.parse()?) + } else if input.peek(Token![const]) && input.peek2(token::Brace) { + Expr::Const(input.parse()?) + } else if input.peek(token::Brace) { + Expr::Block(input.parse()?) + } else if input.peek(Lifetime) { + atom_labeled(input)? + } else { + let allow_struct = AllowStruct(true); + unary_expr(input, allow_struct)? + }; + + if continue_parsing_early(&expr) { + attrs.extend(expr.replace_attrs(Vec::new())); + expr.replace_attrs(attrs); + + let allow_struct = AllowStruct(true); + return parse_expr(input, expr, allow_struct, Precedence::Any); + } + + if input.peek(Token![.]) && !input.peek(Token![..]) || input.peek(Token![?]) { + expr = trailer_helper(input, expr)?; + + attrs.extend(expr.replace_attrs(Vec::new())); + expr.replace_attrs(attrs); + + let allow_struct = AllowStruct(true); + return parse_expr(input, expr, allow_struct, Precedence::Any); + } + + attrs.extend(expr.replace_attrs(Vec::new())); + expr.replace_attrs(attrs); + Ok(expr) + } + + #[cfg(feature = "full")] + fn continue_parsing_early(mut expr: &Expr) -> bool { + while let Expr::Group(group) = expr { + expr = &group.expr; + } + match expr { + Expr::If(_) + | Expr::While(_) + | Expr::ForLoop(_) + | Expr::Loop(_) + | Expr::Match(_) + | Expr::TryBlock(_) + | Expr::Unsafe(_) + | Expr::Const(_) + | Expr::Block(_) => false, + _ => true, + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprLit { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprLit { + attrs: Vec::new(), + lit: input.parse()?, + }) + } + } + + fn expr_group( + input: ParseStream, + #[cfg(feature = "full")] allow_struct: AllowStruct, + ) -> Result<Expr> { + let group = crate::group::parse_group(input)?; + let mut inner: Expr = group.content.parse()?; + + match inner { + Expr::Path(mut expr) if expr.attrs.is_empty() => { + let grouped_len = expr.path.segments.len(); + Path::parse_rest(input, &mut expr.path, true)?; + match rest_of_path_or_macro_or_struct( + expr.qself, + expr.path, + input, + #[cfg(feature = "full")] + allow_struct, + )? { + Expr::Path(expr) if expr.path.segments.len() == grouped_len => { + inner = Expr::Path(expr); + } + extended => return Ok(extended), + } + } + _ => {} + } + + Ok(Expr::Group(ExprGroup { + attrs: Vec::new(), + group_token: group.token, + expr: Box::new(inner), + })) + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprParen { + fn parse(input: ParseStream) -> Result<Self> { + expr_paren(input) + } + } + + fn expr_paren(input: ParseStream) -> Result<ExprParen> { + let content; + Ok(ExprParen { + attrs: Vec::new(), + paren_token: parenthesized!(content in input), + expr: content.parse()?, + }) + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprLet { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprLet { + attrs: Vec::new(), + let_token: input.parse()?, + pat: Box::new(Pat::parse_multi_with_leading_vert(input)?), + eq_token: input.parse()?, + expr: Box::new({ + let allow_struct = AllowStruct(false); + let lhs = unary_expr(input, allow_struct)?; + parse_expr(input, lhs, allow_struct, Precedence::Compare)? + }), + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprIf { + fn parse(input: ParseStream) -> Result<Self> { + let attrs = input.call(Attribute::parse_outer)?; + Ok(ExprIf { + attrs, + if_token: input.parse()?, + cond: Box::new(input.call(Expr::parse_without_eager_brace)?), + then_branch: input.parse()?, + else_branch: { + if input.peek(Token![else]) { + Some(input.call(else_block)?) + } else { + None + } + }, + }) + } + } + + #[cfg(feature = "full")] + fn else_block(input: ParseStream) -> Result<(Token![else], Box<Expr>)> { + let else_token: Token![else] = input.parse()?; + + let lookahead = input.lookahead1(); + let else_branch = if lookahead.peek(Token![if]) { + input.parse().map(Expr::If)? + } else if lookahead.peek(token::Brace) { + Expr::Block(ExprBlock { + attrs: Vec::new(), + label: None, + block: input.parse()?, + }) + } else { + return Err(lookahead.error()); + }; + + Ok((else_token, Box::new(else_branch))) + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprInfer { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprInfer { + attrs: input.call(Attribute::parse_outer)?, + underscore_token: input.parse()?, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprForLoop { + fn parse(input: ParseStream) -> Result<Self> { + let mut attrs = input.call(Attribute::parse_outer)?; + let label: Option<Label> = input.parse()?; + let for_token: Token![for] = input.parse()?; + + let pat = Pat::parse_multi_with_leading_vert(input)?; + + let in_token: Token![in] = input.parse()?; + let expr: Expr = input.call(Expr::parse_without_eager_brace)?; + + let content; + let brace_token = braced!(content in input); + attr::parsing::parse_inner(&content, &mut attrs)?; + let stmts = content.call(Block::parse_within)?; + + Ok(ExprForLoop { + attrs, + label, + for_token, + pat: Box::new(pat), + in_token, + expr: Box::new(expr), + body: Block { brace_token, stmts }, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprLoop { + fn parse(input: ParseStream) -> Result<Self> { + let mut attrs = input.call(Attribute::parse_outer)?; + let label: Option<Label> = input.parse()?; + let loop_token: Token![loop] = input.parse()?; + + let content; + let brace_token = braced!(content in input); + attr::parsing::parse_inner(&content, &mut attrs)?; + let stmts = content.call(Block::parse_within)?; + + Ok(ExprLoop { + attrs, + label, + loop_token, + body: Block { brace_token, stmts }, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprMatch { + fn parse(input: ParseStream) -> Result<Self> { + let mut attrs = input.call(Attribute::parse_outer)?; + let match_token: Token![match] = input.parse()?; + let expr = Expr::parse_without_eager_brace(input)?; + + let content; + let brace_token = braced!(content in input); + attr::parsing::parse_inner(&content, &mut attrs)?; + + let mut arms = Vec::new(); + while !content.is_empty() { + arms.push(content.call(Arm::parse)?); + } + + Ok(ExprMatch { + attrs, + match_token, + expr: Box::new(expr), + brace_token, + arms, + }) + } + } + + macro_rules! impl_by_parsing_expr { + ( + $( + $expr_type:ty, $variant:ident, $msg:expr, + )* + ) => { + $( + #[cfg(all(feature = "full", feature = "printing"))] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for $expr_type { + fn parse(input: ParseStream) -> Result<Self> { + let mut expr: Expr = input.parse()?; + loop { + match expr { + Expr::$variant(inner) => return Ok(inner), + Expr::Group(next) => expr = *next.expr, + _ => return Err(Error::new_spanned(expr, $msg)), + } + } + } + } + )* + }; + } + + impl_by_parsing_expr! { + ExprAssign, Assign, "expected assignment expression", + ExprAwait, Await, "expected await expression", + ExprBinary, Binary, "expected binary operation", + ExprCall, Call, "expected function call expression", + ExprCast, Cast, "expected cast expression", + ExprField, Field, "expected struct field access", + ExprIndex, Index, "expected indexing expression", + ExprMethodCall, MethodCall, "expected method call expression", + ExprRange, Range, "expected range expression", + ExprTry, Try, "expected try expression", + ExprTuple, Tuple, "expected tuple expression", + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprUnary { + fn parse(input: ParseStream) -> Result<Self> { + let attrs = Vec::new(); + let allow_struct = AllowStruct(true); + expr_unary(input, attrs, allow_struct) + } + } + + #[cfg(feature = "full")] + fn expr_unary( + input: ParseStream, + attrs: Vec<Attribute>, + allow_struct: AllowStruct, + ) -> Result<ExprUnary> { + Ok(ExprUnary { + attrs, + op: input.parse()?, + expr: Box::new(unary_expr(input, allow_struct)?), + }) + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprClosure { + fn parse(input: ParseStream) -> Result<Self> { + let allow_struct = AllowStruct(true); + expr_closure(input, allow_struct) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprReference { + fn parse(input: ParseStream) -> Result<Self> { + let allow_struct = AllowStruct(true); + Ok(ExprReference { + attrs: Vec::new(), + and_token: input.parse()?, + mutability: input.parse()?, + expr: Box::new(unary_expr(input, allow_struct)?), + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprBreak { + fn parse(input: ParseStream) -> Result<Self> { + let allow_struct = AllowStruct(true); + expr_break(input, allow_struct) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprReturn { + fn parse(input: ParseStream) -> Result<Self> { + let allow_struct = AllowStruct(true); + expr_return(input, allow_struct) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprTryBlock { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprTryBlock { + attrs: Vec::new(), + try_token: input.parse()?, + block: input.parse()?, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprYield { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprYield { + attrs: Vec::new(), + yield_token: input.parse()?, + expr: { + if can_begin_expr(input) { + Some(input.parse()?) + } else { + None + } + }, + }) + } + } + + #[cfg(feature = "full")] + fn expr_closure(input: ParseStream, allow_struct: AllowStruct) -> Result<ExprClosure> { + let lifetimes: Option<BoundLifetimes> = input.parse()?; + let constness: Option<Token![const]> = input.parse()?; + let movability: Option<Token![static]> = input.parse()?; + let asyncness: Option<Token![async]> = input.parse()?; + let capture: Option<Token![move]> = input.parse()?; + let or1_token: Token![|] = input.parse()?; + + let mut inputs = Punctuated::new(); + loop { + if input.peek(Token![|]) { + break; + } + let value = closure_arg(input)?; + inputs.push_value(value); + if input.peek(Token![|]) { + break; + } + let punct: Token![,] = input.parse()?; + inputs.push_punct(punct); + } + + let or2_token: Token![|] = input.parse()?; + + let (output, body) = if input.peek(Token![->]) { + let arrow_token: Token![->] = input.parse()?; + let ty: Type = input.parse()?; + let body: Block = input.parse()?; + let output = ReturnType::Type(arrow_token, Box::new(ty)); + let block = Expr::Block(ExprBlock { + attrs: Vec::new(), + label: None, + block: body, + }); + (output, block) + } else { + let body = ambiguous_expr(input, allow_struct)?; + (ReturnType::Default, body) + }; + + Ok(ExprClosure { + attrs: Vec::new(), + lifetimes, + constness, + movability, + asyncness, + capture, + or1_token, + inputs, + or2_token, + output, + body: Box::new(body), + }) + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprAsync { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprAsync { + attrs: Vec::new(), + async_token: input.parse()?, + capture: input.parse()?, + block: input.parse()?, + }) + } + } + + #[cfg(feature = "full")] + fn closure_arg(input: ParseStream) -> Result<Pat> { + let attrs = input.call(Attribute::parse_outer)?; + let mut pat = Pat::parse_single(input)?; + + if input.peek(Token![:]) { + Ok(Pat::Type(PatType { + attrs, + pat: Box::new(pat), + colon_token: input.parse()?, + ty: input.parse()?, + })) + } else { + match &mut pat { + Pat::Const(pat) => pat.attrs = attrs, + Pat::Ident(pat) => pat.attrs = attrs, + Pat::Lit(pat) => pat.attrs = attrs, + Pat::Macro(pat) => pat.attrs = attrs, + Pat::Or(pat) => pat.attrs = attrs, + Pat::Paren(pat) => pat.attrs = attrs, + Pat::Path(pat) => pat.attrs = attrs, + Pat::Range(pat) => pat.attrs = attrs, + Pat::Reference(pat) => pat.attrs = attrs, + Pat::Rest(pat) => pat.attrs = attrs, + Pat::Slice(pat) => pat.attrs = attrs, + Pat::Struct(pat) => pat.attrs = attrs, + Pat::Tuple(pat) => pat.attrs = attrs, + Pat::TupleStruct(pat) => pat.attrs = attrs, + Pat::Type(_) => unreachable!(), + Pat::Verbatim(_) => {} + Pat::Wild(pat) => pat.attrs = attrs, + } + Ok(pat) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprWhile { + fn parse(input: ParseStream) -> Result<Self> { + let mut attrs = input.call(Attribute::parse_outer)?; + let label: Option<Label> = input.parse()?; + let while_token: Token![while] = input.parse()?; + let cond = Expr::parse_without_eager_brace(input)?; + + let content; + let brace_token = braced!(content in input); + attr::parsing::parse_inner(&content, &mut attrs)?; + let stmts = content.call(Block::parse_within)?; + + Ok(ExprWhile { + attrs, + label, + while_token, + cond: Box::new(cond), + body: Block { brace_token, stmts }, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprConst { + fn parse(input: ParseStream) -> Result<Self> { + let const_token: Token![const] = input.parse()?; + + let content; + let brace_token = braced!(content in input); + let inner_attrs = content.call(Attribute::parse_inner)?; + let stmts = content.call(Block::parse_within)?; + + Ok(ExprConst { + attrs: inner_attrs, + const_token, + block: Block { brace_token, stmts }, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for Label { + fn parse(input: ParseStream) -> Result<Self> { + Ok(Label { + name: input.parse()?, + colon_token: input.parse()?, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for Option<Label> { + fn parse(input: ParseStream) -> Result<Self> { + if input.peek(Lifetime) { + input.parse().map(Some) + } else { + Ok(None) + } + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprContinue { + fn parse(input: ParseStream) -> Result<Self> { + Ok(ExprContinue { + attrs: Vec::new(), + continue_token: input.parse()?, + label: input.parse()?, + }) + } + } + + #[cfg(feature = "full")] + fn expr_break(input: ParseStream, allow_struct: AllowStruct) -> Result<ExprBreak> { + let break_token: Token![break] = input.parse()?; + + let ahead = input.fork(); + let label: Option<Lifetime> = ahead.parse()?; + if label.is_some() && ahead.peek(Token![:]) { + // Not allowed: `break 'label: loop {...}` + // Parentheses are required. `break ('label: loop {...})` + let _ = ambiguous_expr(input, allow_struct)?; + let start_span = label.unwrap().apostrophe; + let end_span = input.cursor().prev_span(); + return Err(crate::error::new2( + start_span, + end_span, + "parentheses required", + )); + } + + input.advance_to(&ahead); + let expr = if can_begin_expr(input) && (allow_struct.0 || !input.peek(token::Brace)) { + let expr = ambiguous_expr(input, allow_struct)?; + Some(Box::new(expr)) + } else { + None + }; + + Ok(ExprBreak { + attrs: Vec::new(), + break_token, + label, + expr, + }) + } + + #[cfg(feature = "full")] + fn expr_return(input: ParseStream, allow_struct: AllowStruct) -> Result<ExprReturn> { + Ok(ExprReturn { + attrs: Vec::new(), + return_token: input.parse()?, + expr: { + if can_begin_expr(input) { + // NOTE: return is greedy and eats blocks after it even when in a + // position where structs are not allowed, such as in if statement + // conditions. For example: + // + // if return { println!("A") } {} // Prints "A" + let expr = ambiguous_expr(input, allow_struct)?; + Some(Box::new(expr)) + } else { + None + } + }, + }) + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for FieldValue { + fn parse(input: ParseStream) -> Result<Self> { + let attrs = input.call(Attribute::parse_outer)?; + let member: Member = input.parse()?; + let (colon_token, value) = if input.peek(Token![:]) || !member.is_named() { + let colon_token: Token![:] = input.parse()?; + let value: Expr = input.parse()?; + (Some(colon_token), value) + } else if let Member::Named(ident) = &member { + let value = Expr::Path(ExprPath { + attrs: Vec::new(), + qself: None, + path: Path::from(ident.clone()), + }); + (None, value) + } else { + unreachable!() + }; + + Ok(FieldValue { + attrs, + member, + colon_token, + expr: value, + }) + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprStruct { + fn parse(input: ParseStream) -> Result<Self> { + let (qself, path) = path::parsing::qpath(input, true)?; + expr_struct_helper(input, qself, path) + } + } + + fn expr_struct_helper( + input: ParseStream, + qself: Option<QSelf>, + path: Path, + ) -> Result<ExprStruct> { + let content; + let brace_token = braced!(content in input); + + let mut fields = Punctuated::new(); + while !content.is_empty() { + if content.peek(Token![..]) { + return Ok(ExprStruct { + attrs: Vec::new(), + qself, + path, + brace_token, + fields, + dot2_token: Some(content.parse()?), + rest: if content.is_empty() { + None + } else { + Some(Box::new(content.parse()?)) + }, + }); + } + + fields.push(content.parse()?); + if content.is_empty() { + break; + } + let punct: Token![,] = content.parse()?; + fields.push_punct(punct); + } + + Ok(ExprStruct { + attrs: Vec::new(), + qself, + path, + brace_token, + fields, + dot2_token: None, + rest: None, + }) + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprUnsafe { + fn parse(input: ParseStream) -> Result<Self> { + let unsafe_token: Token![unsafe] = input.parse()?; + + let content; + let brace_token = braced!(content in input); + let inner_attrs = content.call(Attribute::parse_inner)?; + let stmts = content.call(Block::parse_within)?; + + Ok(ExprUnsafe { + attrs: inner_attrs, + unsafe_token, + block: Block { brace_token, stmts }, + }) + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprBlock { + fn parse(input: ParseStream) -> Result<Self> { + let mut attrs = input.call(Attribute::parse_outer)?; + let label: Option<Label> = input.parse()?; + + let content; + let brace_token = braced!(content in input); + attr::parsing::parse_inner(&content, &mut attrs)?; + let stmts = content.call(Block::parse_within)?; + + Ok(ExprBlock { + attrs, + label, + block: Block { brace_token, stmts }, + }) + } + } + + #[cfg(feature = "full")] + fn expr_range(input: ParseStream, allow_struct: AllowStruct) -> Result<ExprRange> { + let limits: RangeLimits = input.parse()?; + let end = if matches!(limits, RangeLimits::HalfOpen(_)) + && (input.is_empty() + || input.peek(Token![,]) + || input.peek(Token![;]) + || input.peek(Token![.]) && !input.peek(Token![..]) + || !allow_struct.0 && input.peek(token::Brace)) + { + None + } else { + let to = ambiguous_expr(input, allow_struct)?; + Some(Box::new(to)) + }; + Ok(ExprRange { + attrs: Vec::new(), + start: None, + limits, + end, + }) + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for RangeLimits { + fn parse(input: ParseStream) -> Result<Self> { + let lookahead = input.lookahead1(); + let dot_dot = lookahead.peek(Token![..]); + let dot_dot_eq = dot_dot && lookahead.peek(Token![..=]); + let dot_dot_dot = dot_dot && input.peek(Token![...]); + if dot_dot_eq { + input.parse().map(RangeLimits::Closed) + } else if dot_dot && !dot_dot_dot { + input.parse().map(RangeLimits::HalfOpen) + } else { + Err(lookahead.error()) + } + } + } + + #[cfg(feature = "full")] + impl RangeLimits { + pub(crate) fn parse_obsolete(input: ParseStream) -> Result<Self> { + let lookahead = input.lookahead1(); + let dot_dot = lookahead.peek(Token![..]); + let dot_dot_eq = dot_dot && lookahead.peek(Token![..=]); + let dot_dot_dot = dot_dot && input.peek(Token![...]); + if dot_dot_eq { + input.parse().map(RangeLimits::Closed) + } else if dot_dot_dot { + let dot3: Token![...] = input.parse()?; + Ok(RangeLimits::Closed(Token)) + } else if dot_dot { + input.parse().map(RangeLimits::HalfOpen) + } else { + Err(lookahead.error()) + } + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for ExprPath { + fn parse(input: ParseStream) -> Result<Self> { + #[cfg(not(feature = "full"))] + let attrs = Vec::new(); + #[cfg(feature = "full")] + let attrs = input.call(Attribute::parse_outer)?; + + let (qself, path) = path::parsing::qpath(input, true)?; + + Ok(ExprPath { attrs, qself, path }) + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for Member { + fn parse(input: ParseStream) -> Result<Self> { + if input.peek(Ident) { + input.parse().map(Member::Named) + } else if input.peek(LitInt) { + input.parse().map(Member::Unnamed) + } else { + Err(input.error("expected identifier or integer")) + } + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for Arm { + fn parse(input: ParseStream) -> Result<Arm> { + let requires_comma; + Ok(Arm { + attrs: input.call(Attribute::parse_outer)?, + pat: Pat::parse_multi_with_leading_vert(input)?, + guard: { + if input.peek(Token![if]) { + let if_token: Token![if] = input.parse()?; + let guard: Expr = input.parse()?; + Some((if_token, Box::new(guard))) + } else { + None + } + }, + fat_arrow_token: input.parse()?, + body: { + let body = input.call(expr_early)?; + requires_comma = requires_terminator(&body); + Box::new(body) + }, + comma: { + if requires_comma && !input.is_empty() { + Some(input.parse()?) + } else { + input.parse()? + } + }, + }) + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for Index { + fn parse(input: ParseStream) -> Result<Self> { + let lit: LitInt = input.parse()?; + if lit.suffix().is_empty() { + Ok(Index { + index: lit + .base10_digits() + .parse() + .map_err(|err| Error::new(lit.span(), err))?, + span: lit.span(), + }) + } else { + Err(Error::new(lit.span(), "expected unsuffixed integer")) + } + } + } + + fn multi_index(e: &mut Expr, dot_token: &mut Token![.], float: LitFloat) -> Result<bool> { + let float_token = float.token(); + let float_span = float_token.span(); + let mut float_repr = float_token.to_string(); + let trailing_dot = float_repr.ends_with('.'); + if trailing_dot { + float_repr.truncate(float_repr.len() - 1); + } + + let mut offset = 0; + for part in float_repr.split('.') { + let mut index: Index = + crate::parse_str(part).map_err(|err| Error::new(float_span, err))?; + let part_end = offset + part.len(); + index.span = float_token.subspan(offset..part_end).unwrap_or(float_span); + + let base = mem::replace(e, Expr::DUMMY); + *e = Expr::Field(ExprField { + attrs: Vec::new(), + base: Box::new(base), + dot_token: Token, + member: Member::Unnamed(index), + }); + + let dot_span = float_token + .subspan(part_end..part_end + 1) + .unwrap_or(float_span); + *dot_token = Token; + offset = part_end + 1; + } + + Ok(!trailing_dot) + } + + impl Member { + pub(crate) fn is_named(&self) -> bool { + match self { + Member::Named(_) => true, + Member::Unnamed(_) => false, + } + } + } + + fn check_cast(input: ParseStream) -> Result<()> { + let kind = if input.peek(Token![.]) && !input.peek(Token![..]) { + if input.peek2(Token![await]) { + "`.await`" + } else if input.peek2(Ident) && (input.peek3(token::Paren) || input.peek3(Token![::])) { + "a method call" + } else { + "a field access" + } + } else if input.peek(Token![?]) { + "`?`" + } else if input.peek(token::Bracket) { + "indexing" + } else if input.peek(token::Paren) { + "a function call" + } else { + return Ok(()); + }; + let msg = format!("casts cannot be followed by {}", kind); + Err(input.error(msg)) + } +} + +#[cfg(feature = "printing")] +pub(crate) mod printing { + use super::*; + #[cfg(feature = "full")] + use crate::attr::FilterAttrs; + use proc_macro2::{Literal, TokenStream}; + use quote::{ToTokens, TokenStreamExt}; + + // If the given expression is a bare `ExprStruct`, wraps it in parenthesis + // before appending it to `TokenStream`. + #[cfg(feature = "full")] + fn wrap_bare_struct(tokens: &mut TokenStream, e: &Expr) { + if let Expr::Struct(_) = *e { + token::Paren::default().surround(tokens, |tokens| { + e.to_tokens(tokens); + }); + } else { + e.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + pub(crate) fn outer_attrs_to_tokens(attrs: &[Attribute], tokens: &mut TokenStream) { + tokens.append_all(attrs.outer()); + } + + #[cfg(feature = "full")] + fn inner_attrs_to_tokens(attrs: &[Attribute], tokens: &mut TokenStream) { + tokens.append_all(attrs.inner()); + } + + #[cfg(not(feature = "full"))] + pub(crate) fn outer_attrs_to_tokens(_attrs: &[Attribute], _tokens: &mut TokenStream) {} + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprArray { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.bracket_token.surround(tokens, |tokens| { + self.elems.to_tokens(tokens); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprAssign { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.left.to_tokens(tokens); + self.eq_token.to_tokens(tokens); + self.right.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprAsync { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.async_token.to_tokens(tokens); + self.capture.to_tokens(tokens); + self.block.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprAwait { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.base.to_tokens(tokens); + self.dot_token.to_tokens(tokens); + self.await_token.to_tokens(tokens); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprBinary { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.left.to_tokens(tokens); + self.op.to_tokens(tokens); + self.right.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprBlock { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.label.to_tokens(tokens); + self.block.brace_token.surround(tokens, |tokens| { + inner_attrs_to_tokens(&self.attrs, tokens); + tokens.append_all(&self.block.stmts); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprBreak { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.break_token.to_tokens(tokens); + self.label.to_tokens(tokens); + self.expr.to_tokens(tokens); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprCall { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.func.to_tokens(tokens); + self.paren_token.surround(tokens, |tokens| { + self.args.to_tokens(tokens); + }); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprCast { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.expr.to_tokens(tokens); + self.as_token.to_tokens(tokens); + self.ty.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprClosure { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.lifetimes.to_tokens(tokens); + self.constness.to_tokens(tokens); + self.movability.to_tokens(tokens); + self.asyncness.to_tokens(tokens); + self.capture.to_tokens(tokens); + self.or1_token.to_tokens(tokens); + self.inputs.to_tokens(tokens); + self.or2_token.to_tokens(tokens); + self.output.to_tokens(tokens); + self.body.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprConst { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.const_token.to_tokens(tokens); + self.block.brace_token.surround(tokens, |tokens| { + inner_attrs_to_tokens(&self.attrs, tokens); + tokens.append_all(&self.block.stmts); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprContinue { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.continue_token.to_tokens(tokens); + self.label.to_tokens(tokens); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprField { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.base.to_tokens(tokens); + self.dot_token.to_tokens(tokens); + self.member.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprForLoop { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.label.to_tokens(tokens); + self.for_token.to_tokens(tokens); + self.pat.to_tokens(tokens); + self.in_token.to_tokens(tokens); + wrap_bare_struct(tokens, &self.expr); + self.body.brace_token.surround(tokens, |tokens| { + inner_attrs_to_tokens(&self.attrs, tokens); + tokens.append_all(&self.body.stmts); + }); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprGroup { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.group_token.surround(tokens, |tokens| { + self.expr.to_tokens(tokens); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprIf { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.if_token.to_tokens(tokens); + wrap_bare_struct(tokens, &self.cond); + self.then_branch.to_tokens(tokens); + if let Some((else_token, else_)) = &self.else_branch { + else_token.to_tokens(tokens); + // If we are not one of the valid expressions to exist in an else + // clause, wrap ourselves in a block. + match **else_ { + Expr::If(_) | Expr::Block(_) => else_.to_tokens(tokens), + _ => token::Brace::default().surround(tokens, |tokens| else_.to_tokens(tokens)), + } + } + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprIndex { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.expr.to_tokens(tokens); + self.bracket_token.surround(tokens, |tokens| { + self.index.to_tokens(tokens); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprInfer { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.underscore_token.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprLet { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.let_token.to_tokens(tokens); + self.pat.to_tokens(tokens); + self.eq_token.to_tokens(tokens); + wrap_bare_struct(tokens, &self.expr); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprLit { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.lit.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprLoop { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.label.to_tokens(tokens); + self.loop_token.to_tokens(tokens); + self.body.brace_token.surround(tokens, |tokens| { + inner_attrs_to_tokens(&self.attrs, tokens); + tokens.append_all(&self.body.stmts); + }); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprMacro { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.mac.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprMatch { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.match_token.to_tokens(tokens); + wrap_bare_struct(tokens, &self.expr); + self.brace_token.surround(tokens, |tokens| { + inner_attrs_to_tokens(&self.attrs, tokens); + for (i, arm) in self.arms.iter().enumerate() { + arm.to_tokens(tokens); + // Ensure that we have a comma after a non-block arm, except + // for the last one. + let is_last = i == self.arms.len() - 1; + if !is_last && requires_terminator(&arm.body) && arm.comma.is_none() { + <Token![,]>::default().to_tokens(tokens); + } + } + }); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprMethodCall { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.receiver.to_tokens(tokens); + self.dot_token.to_tokens(tokens); + self.method.to_tokens(tokens); + self.turbofish.to_tokens(tokens); + self.paren_token.surround(tokens, |tokens| { + self.args.to_tokens(tokens); + }); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprParen { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.paren_token.surround(tokens, |tokens| { + self.expr.to_tokens(tokens); + }); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprPath { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + path::printing::print_path(tokens, &self.qself, &self.path); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprRange { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.start.to_tokens(tokens); + self.limits.to_tokens(tokens); + self.end.to_tokens(tokens); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprReference { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.and_token.to_tokens(tokens); + self.mutability.to_tokens(tokens); + self.expr.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprRepeat { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.bracket_token.surround(tokens, |tokens| { + self.expr.to_tokens(tokens); + self.semi_token.to_tokens(tokens); + self.len.to_tokens(tokens); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprReturn { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.return_token.to_tokens(tokens); + self.expr.to_tokens(tokens); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprStruct { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + path::printing::print_path(tokens, &self.qself, &self.path); + self.brace_token.surround(tokens, |tokens| { + self.fields.to_tokens(tokens); + if let Some(dot2_token) = &self.dot2_token { + dot2_token.to_tokens(tokens); + } else if self.rest.is_some() { + Token).to_tokens(tokens); + } + self.rest.to_tokens(tokens); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprTry { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.expr.to_tokens(tokens); + self.question_token.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprTryBlock { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.try_token.to_tokens(tokens); + self.block.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprTuple { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.paren_token.surround(tokens, |tokens| { + self.elems.to_tokens(tokens); + // If we only have one argument, we need a trailing comma to + // distinguish ExprTuple from ExprParen. + if self.elems.len() == 1 && !self.elems.trailing_punct() { + <Token![,]>::default().to_tokens(tokens); + } + }); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprUnary { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.op.to_tokens(tokens); + self.expr.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprUnsafe { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.unsafe_token.to_tokens(tokens); + self.block.brace_token.surround(tokens, |tokens| { + inner_attrs_to_tokens(&self.attrs, tokens); + tokens.append_all(&self.block.stmts); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprWhile { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.label.to_tokens(tokens); + self.while_token.to_tokens(tokens); + wrap_bare_struct(tokens, &self.cond); + self.body.brace_token.surround(tokens, |tokens| { + inner_attrs_to_tokens(&self.attrs, tokens); + tokens.append_all(&self.body.stmts); + }); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for ExprYield { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.yield_token.to_tokens(tokens); + self.expr.to_tokens(tokens); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for Arm { + fn to_tokens(&self, tokens: &mut TokenStream) { + tokens.append_all(&self.attrs); + self.pat.to_tokens(tokens); + if let Some((if_token, guard)) = &self.guard { + if_token.to_tokens(tokens); + guard.to_tokens(tokens); + } + self.fat_arrow_token.to_tokens(tokens); + self.body.to_tokens(tokens); + self.comma.to_tokens(tokens); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for FieldValue { + fn to_tokens(&self, tokens: &mut TokenStream) { + outer_attrs_to_tokens(&self.attrs, tokens); + self.member.to_tokens(tokens); + if let Some(colon_token) = &self.colon_token { + colon_token.to_tokens(tokens); + self.expr.to_tokens(tokens); + } + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for Index { + fn to_tokens(&self, tokens: &mut TokenStream) { + let mut lit = Literal::i64_unsuffixed(i64::from(self.index)); + lit.set_span(self.span); + tokens.append(lit); + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for Label { + fn to_tokens(&self, tokens: &mut TokenStream) { + self.name.to_tokens(tokens); + self.colon_token.to_tokens(tokens); + } + } + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for Member { + fn to_tokens(&self, tokens: &mut TokenStream) { + match self { + Member::Named(ident) => ident.to_tokens(tokens), + Member::Unnamed(index) => index.to_tokens(tokens), + } + } + } + + #[cfg(feature = "full")] + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for RangeLimits { + fn to_tokens(&self, tokens: &mut TokenStream) { + match self { + RangeLimits::HalfOpen(t) => t.to_tokens(tokens), + RangeLimits::Closed(t) => t.to_tokens(tokens), + } + } + } +} |