diff options
Diffstat (limited to 'vendor/syn/src/expr.rs')
| -rw-r--r-- | vendor/syn/src/expr.rs | 4174 |
1 files changed, 0 insertions, 4174 deletions
diff --git a/vendor/syn/src/expr.rs b/vendor/syn/src/expr.rs deleted file mode 100644 index 48d240af..00000000 --- a/vendor/syn/src/expr.rs +++ /dev/null @@ -1,4174 +0,0 @@ -use crate::attr::Attribute; -#[cfg(all(feature = "parsing", feature = "full"))] -use crate::error::Result; -#[cfg(feature = "parsing")] -use crate::ext::IdentExt as _; -#[cfg(feature = "full")] -use crate::generics::BoundLifetimes; -use crate::ident::Ident; -#[cfg(any(feature = "parsing", feature = "full"))] -use crate::lifetime::Lifetime; -use crate::lit::Lit; -use crate::mac::Macro; -use crate::op::{BinOp, UnOp}; -#[cfg(feature = "parsing")] -use crate::parse::ParseStream; -#[cfg(feature = "full")] -use crate::pat::Pat; -use crate::path::{AngleBracketedGenericArguments, Path, QSelf}; -use crate::punctuated::Punctuated; -#[cfg(feature = "full")] -use crate::stmt::Block; -use crate::token; -#[cfg(feature = "full")] -use crate::ty::ReturnType; -use crate::ty::Type; -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(all(feature = "parsing", feature = "full"))] -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(docsrs, 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), - - /// Address-of operation: `&raw const place` or `&raw mut place`. - RawAddr(ExprRawAddr), - - /// 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] - pub struct ExprLit { - pub attrs: Vec<Attribute>, - pub lit: Lit, - } -} - -ast_struct! { - /// Conditionless loop: `loop { ... }`. - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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! { - /// Address-of operation: `&raw const place` or `&raw mut place`. - #[cfg_attr(docsrs, doc(cfg(feature = "full")))] - pub struct ExprRawAddr #full { - pub attrs: Vec<Attribute>, - pub and_token: Token![&], - pub raw: Token![raw], - pub mutability: PointerMutability, - pub expr: Box<Expr>, - } -} - -ast_struct! { - /// A referencing operation: `&a` or `&mut a`. - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, doc(cfg(feature = "full")))] - pub struct ExprTuple { - pub attrs: Vec<Attribute>, - pub paren_token: token::Paren, - pub elems: Punctuated<Expr, Token![,]>, - } -} - -ast_struct! { - /// A unary operation: `!x`, `*x`. - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, doc(cfg(feature = "full")))] - pub struct ExprYield #full { - pub attrs: Vec<Attribute>, - pub yield_token: Token![yield], - pub expr: Option<Box<Expr>>, - } -} - -impl Expr { - /// An unspecified invalid expression. - /// - /// ``` - /// use quote::ToTokens; - /// use std::mem; - /// use syn::{parse_quote, Expr}; - /// - /// fn unparenthesize(e: &mut Expr) { - /// while let Expr::Paren(paren) = e { - /// *e = mem::replace(&mut *paren.expr, Expr::PLACEHOLDER); - /// } - /// } - /// - /// fn main() { - /// let mut e: Expr = parse_quote! { ((1 + 1)) }; - /// unparenthesize(&mut e); - /// assert_eq!("1 + 1", e.to_token_stream().to_string()); - /// } - /// ``` - pub const PLACEHOLDER: Self = Expr::Path(ExprPath { - attrs: Vec::new(), - qself: None, - path: Path { - leading_colon: None, - segments: Punctuated::new(), - }, - }); - - /// 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. - /// - /// [`Parse`]: crate::parse::Parse - /// - /// 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(all(feature = "full", feature = "parsing"))] - #[cfg_attr(docsrs, doc(cfg(all(feature = "full", feature = "parsing"))))] - pub fn parse_without_eager_brace(input: ParseStream) -> Result<Expr> { - parsing::ambiguous_expr(input, parsing::AllowStruct(false)) - } - - /// An alternative to the primary `Expr::parse` parser (from the [`Parse`] - /// trait) for syntactic positions in which expression boundaries are placed - /// more eagerly than done by the typical expression grammar. This includes - /// expressions at the head of a statement or in the right-hand side of a - /// `match` arm. - /// - /// [`Parse`]: crate::parse::Parse - /// - /// Compare the following cases: - /// - /// 1. - /// ``` - /// # let result = (); - /// # let guard = false; - /// # let cond = true; - /// # let f = true; - /// # let g = f; - /// # - /// let _ = match result { - /// () if guard => if cond { f } else { g } - /// () => false, - /// }; - /// ``` - /// - /// 2. - /// ``` - /// # let cond = true; - /// # let f = (); - /// # let g = f; - /// # - /// let _ = || { - /// if cond { f } else { g } - /// () - /// }; - /// ``` - /// - /// 3. - /// ``` - /// # let cond = true; - /// # let f = || (); - /// # let g = f; - /// # - /// let _ = [if cond { f } else { g } ()]; - /// ``` - /// - /// The same sequence of tokens `if cond { f } else { g } ()` appears in - /// expression position 3 times. The first two syntactic positions use eager - /// placement of expression boundaries, and parse as `Expr::If`, with the - /// adjacent `()` becoming `Pat::Tuple` or `Expr::Tuple`. In contrast, the - /// third case uses standard expression boundaries and parses as - /// `Expr::Call`. - /// - /// As with [`parse_without_eager_brace`], this ambiguity in the Rust - /// grammar is independent of precedence. - /// - /// [`parse_without_eager_brace`]: Self::parse_without_eager_brace - #[cfg(all(feature = "full", feature = "parsing"))] - #[cfg_attr(docsrs, doc(cfg(all(feature = "full", feature = "parsing"))))] - pub fn parse_with_earlier_boundary_rule(input: ParseStream) -> Result<Expr> { - parsing::parse_with_earlier_boundary_rule(input) - } - - /// Returns whether the next token in the parse stream is one that might - /// possibly form the beginning of an expr. - /// - /// This classification is a load-bearing part of the grammar of some Rust - /// expressions, notably `return` and `break`. For example `return < …` will - /// never parse `<` as a binary operator regardless of what comes after, - /// because `<` is a legal starting token for an expression and so it's - /// required to be continued as a return value, such as `return <Struct as - /// Trait>::CONST`. Meanwhile `return > …` treats the `>` as a binary - /// operator because it cannot be a starting token for any Rust expression. - #[cfg(feature = "parsing")] - #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] - pub fn peek(input: ParseStream) -> bool { - input.peek(Ident::peek_any) && !input.peek(Token![as]) // 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 - || input.peek(Token![<]) && !input.peek(Token![<=]) && !input.peek(Token![<<=]) // associated path - || input.peek(Token![::]) // absolute path - || input.peek(Lifetime) // labeled loop - || input.peek(Token![#]) // expression attributes - } - - #[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::RawAddr(ExprRawAddr { 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(docsrs, 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), - } - } -} - -#[cfg(any(feature = "parsing", feature = "printing"))] -impl Member { - pub(crate) fn is_named(&self) -> bool { - match self { - Member::Named(_) => true, - Member::Unnamed(_) => false, - } - } -} - -ast_struct! { - /// The index of an unnamed tuple struct field. - #[cfg_attr(docsrs, 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 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(feature = "full")] -ast_enum! { - /// Mutability of a raw pointer (`*const T`, `*mut T`), in which non-mutable - /// isn't the implicit default. - #[cfg_attr(docsrs, doc(cfg(feature = "full")))] - pub enum PointerMutability { - Const(Token![const]), - Mut(Token![mut]), - } -} - -#[cfg(feature = "parsing")] -pub(crate) mod parsing { - #[cfg(feature = "full")] - use crate::attr; - use crate::attr::Attribute; - #[cfg(feature = "full")] - use crate::classify; - use crate::error::{Error, Result}; - #[cfg(feature = "full")] - use crate::expr::{ - Arm, ExprArray, ExprAssign, ExprAsync, ExprAwait, ExprBlock, ExprBreak, ExprClosure, - ExprConst, ExprContinue, ExprForLoop, ExprIf, ExprInfer, ExprLet, ExprLoop, ExprMatch, - ExprRange, ExprRawAddr, ExprRepeat, ExprReturn, ExprTry, ExprTryBlock, ExprUnsafe, - ExprWhile, ExprYield, Label, PointerMutability, RangeLimits, - }; - use crate::expr::{ - Expr, ExprBinary, ExprCall, ExprCast, ExprField, ExprGroup, ExprIndex, ExprLit, ExprMacro, - ExprMethodCall, ExprParen, ExprPath, ExprReference, ExprStruct, ExprTuple, ExprUnary, - FieldValue, Index, Member, - }; - #[cfg(feature = "full")] - use crate::generics::BoundLifetimes; - use crate::ident::Ident; - #[cfg(feature = "full")] - use crate::lifetime::Lifetime; - use crate::lit::{Lit, LitFloat, LitInt}; - use crate::mac::{self, Macro}; - use crate::op::BinOp; - use crate::parse::discouraged::Speculative as _; - #[cfg(feature = "full")] - use crate::parse::ParseBuffer; - use crate::parse::{Parse, ParseStream}; - #[cfg(feature = "full")] - use crate::pat::{Pat, PatType}; - use crate::path::{self, AngleBracketedGenericArguments, Path, QSelf}; - use crate::precedence::Precedence; - use crate::punctuated::Punctuated; - #[cfg(feature = "full")] - use crate::stmt::Block; - use crate::token; - use crate::ty; - #[cfg(feature = "full")] - use crate::ty::{ReturnType, Type}; - use crate::verbatim; - #[cfg(feature = "full")] - use proc_macro2::{Span, TokenStream}; - use std::mem; - - // 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(super) struct AllowStruct(pub bool); - - #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for Expr { - fn parse(input: ParseStream) -> Result<Self> { - ambiguous_expr( - input, - #[cfg(feature = "full")] - AllowStruct(true), - ) - } - } - - #[cfg(feature = "full")] - pub(super) fn parse_with_earlier_boundary_rule(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::MIN); - } - - 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::MIN); - } - - attrs.extend(expr.replace_attrs(Vec::new())); - expr.replace_attrs(attrs); - Ok(expr) - } - - #[cfg(feature = "full")] - impl Copy for AllowStruct {} - - #[cfg(feature = "full")] - impl Clone for AllowStruct { - fn clone(&self) -> Self { - *self - } - } - - #[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 Expr::Range(_) = lhs { - // A range cannot be the left-hand side of another binary operator. - break; - } else if let Ok(op) = ahead.parse::<BinOp>() { - let precedence = Precedence::of_binop(&op); - if precedence < base { - break; - } - if precedence == Precedence::Assign { - if let Expr::Range(_) = lhs { - break; - } - } - if precedence == Precedence::Compare { - if let Expr::Binary(lhs) = &lhs { - if Precedence::of_binop(&lhs.op) == Precedence::Compare { - return Err(input.error("comparison operators cannot be chained")); - } - } - } - input.advance_to(&ahead); - let right = parse_binop_rhs(input, allow_struct, precedence)?; - lhs = Expr::Binary(ExprBinary { - attrs: Vec::new(), - left: Box::new(lhs), - op, - right, - }); - } else if Precedence::Assign >= base - && input.peek(Token![=]) - && !input.peek(Token![=>]) - && match lhs { - Expr::Range(_) => false, - _ => true, - } - { - let eq_token: Token![=] = input.parse()?; - let right = parse_binop_rhs(input, allow_struct, Precedence::Assign)?; - lhs = Expr::Assign(ExprAssign { - attrs: Vec::new(), - left: Box::new(lhs), - eq_token, - right, - }); - } else if Precedence::Range >= base && input.peek(Token![..]) { - let limits: RangeLimits = input.parse()?; - let end = parse_range_end(input, &limits, allow_struct)?; - lhs = Expr::Range(ExprRange { - attrs: Vec::new(), - start: Some(Box::new(lhs)), - limits, - end, - }); - } 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 Ok(op) = ahead.parse::<BinOp>() { - let precedence = Precedence::of_binop(&op); - if precedence < base { - break; - } - if precedence == Precedence::Compare { - if let Expr::Binary(lhs) = &lhs { - if Precedence::of_binop(&lhs.op) == Precedence::Compare { - return Err(input.error("comparison operators cannot be chained")); - } - } - } - input.advance_to(&ahead); - let right = parse_binop_rhs(input, precedence)?; - lhs = Expr::Binary(ExprBinary { - attrs: Vec::new(), - left: Box::new(lhs), - op, - right, - }); - } 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 parse_binop_rhs( - input: ParseStream, - #[cfg(feature = "full")] allow_struct: AllowStruct, - precedence: Precedence, - ) -> Result<Box<Expr>> { - let mut rhs = unary_expr( - input, - #[cfg(feature = "full")] - allow_struct, - )?; - loop { - let next = peek_precedence(input); - if next > precedence || next == precedence && precedence == Precedence::Assign { - let cursor = input.cursor(); - rhs = parse_expr( - input, - rhs, - #[cfg(feature = "full")] - allow_struct, - next, - )?; - if cursor == input.cursor() { - // Bespoke grammar restrictions separate from precedence can - // cause parsing to not advance, such as `..a` being - // disallowed in the left-hand side of binary operators, - // even ones that have lower precedence than `..`. - break; - } - } else { - break; - } - } - Ok(Box::new(rhs)) - } - - fn peek_precedence(input: ParseStream) -> Precedence { - if let Ok(op) = input.fork().parse() { - Precedence::of_binop(&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::MIN - } - } - - // Parse an arbitrary expression. - pub(super) 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::MIN, - ) - } - - #[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<Token![raw]> = if input.peek(Token![raw]) - && (input.peek2(Token![mut]) || input.peek2(Token![const])) - { - Some(input.parse()?) - } else { - None - }; - let mutability: Option<Token![mut]> = input.parse()?; - let const_token: Option<Token![const]> = if raw.is_some() && mutability.is_none() { - Some(input.parse()?) - } else { - None - }; - let expr = Box::new(unary_expr(input, allow_struct)?); - if let Some(raw) = raw { - Ok(Expr::RawAddr(ExprRawAddr { - attrs, - and_token, - raw, - mutability: match mutability { - Some(mut_token) => PointerMutability::Mut(mut_token), - None => PointerMutability::Const(const_token.unwrap()), - }, - expr, - })) - } 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 if !attrs.is_empty() { - if let Expr::Range(range) = e { - let spans: &[Span] = match &range.limits { - RangeLimits::HalfOpen(limits) => &limits.spans, - RangeLimits::Closed(limits) => &limits.spans, - }; - return Err(crate::error::new2( - spans[0], - *spans.last().unwrap(), - "attributes are not allowed on range expressions starting with `..`", - )); - } - 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![?]) - && match e { - Expr::Range(_) => false, - _ => true, - } - { - 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 token::parsing::peek_keyword(input.cursor(), "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]) { - input.parse().map(Expr::Return) - } else if input.peek(Token![become]) { - expr_become(input) - } else if input.peek(token::Bracket) { - array_or_repeat(input) - } else if input.peek(Token![let]) { - expr_let(input, allow_struct).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) { - paren_or_tuple(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]) - { - 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(); - - token::parsing::keyword(input, "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 expr_style = true; - let (qself, path) = path::parsing::qpath(input, expr_style)?; - 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(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for ExprMacro { - fn parse(input: ParseStream) -> Result<Self> { - Ok(ExprMacro { - attrs: Vec::new(), - mac: input.parse()?, - }) - } - } - - 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(docsrs, 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(docsrs, 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")] - 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(docsrs, 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(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for ExprParen { - fn parse(input: ParseStream) -> Result<Self> { - let content; - Ok(ExprParen { - attrs: Vec::new(), - paren_token: parenthesized!(content in input), - expr: content.parse()?, - }) - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for ExprLet { - fn parse(input: ParseStream) -> Result<Self> { - let allow_struct = AllowStruct(true); - expr_let(input, allow_struct) - } - } - - #[cfg(feature = "full")] - fn expr_let(input: ParseStream, allow_struct: AllowStruct) -> Result<ExprLet> { - 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 lhs = unary_expr(input, allow_struct)?; - parse_expr(input, lhs, allow_struct, Precedence::Compare)? - }), - }) - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for ExprIf { - fn parse(input: ParseStream) -> Result<Self> { - let attrs = input.call(Attribute::parse_outer)?; - - let mut clauses = Vec::new(); - let mut expr; - loop { - let if_token: Token![if] = input.parse()?; - let cond = input.call(Expr::parse_without_eager_brace)?; - let then_branch: Block = input.parse()?; - - expr = ExprIf { - attrs: Vec::new(), - if_token, - cond: Box::new(cond), - then_branch, - else_branch: None, - }; - - if !input.peek(Token![else]) { - break; - } - - let else_token: Token![else] = input.parse()?; - let lookahead = input.lookahead1(); - if lookahead.peek(Token![if]) { - expr.else_branch = Some((else_token, Box::new(Expr::PLACEHOLDER))); - clauses.push(expr); - } else if lookahead.peek(token::Brace) { - expr.else_branch = Some(( - else_token, - Box::new(Expr::Block(ExprBlock { - attrs: Vec::new(), - label: None, - block: input.parse()?, - })), - )); - break; - } else { - return Err(lookahead.error()); - } - } - - while let Some(mut prev) = clauses.pop() { - *prev.else_branch.as_mut().unwrap().1 = Expr::If(expr); - expr = prev; - } - expr.attrs = attrs; - Ok(expr) - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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 arms = Arm::parse_multiple(&content)?; - - 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for ExprRawAddr { - fn parse(input: ParseStream) -> Result<Self> { - let allow_struct = AllowStruct(true); - Ok(ExprRawAddr { - attrs: Vec::new(), - and_token: input.parse()?, - raw: input.parse()?, - mutability: input.parse()?, - expr: Box::new(unary_expr(input, allow_struct)?), - }) - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for ExprReturn { - fn parse(input: ParseStream) -> Result<Self> { - Ok(ExprReturn { - attrs: Vec::new(), - return_token: input.parse()?, - expr: { - if Expr::peek(input) { - Some(input.parse()?) - } else { - None - } - }, - }) - } - } - - #[cfg(feature = "full")] - fn expr_become(input: ParseStream) -> Result<Expr> { - let begin = input.fork(); - input.parse::<Token![become]>()?; - input.parse::<Expr>()?; - Ok(Expr::Verbatim(verbatim::between(&begin, input))) - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, 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 Expr::peek(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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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 _: Expr = input.parse()?; - 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 Expr::peek(input) && (allow_struct.0 || !input.peek(token::Brace)) { - Some(input.parse()?) - } else { - None - }; - - Ok(ExprBreak { - attrs: Vec::new(), - break_token, - label, - expr, - }) - } - - #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for ExprStruct { - fn parse(input: ParseStream) -> Result<Self> { - let expr_style = true; - let (qself, path) = path::parsing::qpath(input, expr_style)?; - 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(docsrs, 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(docsrs, 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 = parse_range_end(input, &limits, allow_struct)?; - Ok(ExprRange { - attrs: Vec::new(), - start: None, - limits, - end, - }) - } - - #[cfg(feature = "full")] - fn parse_range_end( - input: ParseStream, - limits: &RangeLimits, - allow_struct: AllowStruct, - ) -> Result<Option<Box<Expr>>> { - if matches!(limits, RangeLimits::HalfOpen(_)) - && (input.is_empty() - || input.peek(Token![,]) - || input.peek(Token![;]) - || input.peek(Token![.]) && !input.peek(Token![..]) - || input.peek(Token![?]) - || input.peek(Token![=>]) - || !allow_struct.0 && input.peek(token::Brace) - || input.peek(Token![=]) - || input.peek(Token![+]) - || input.peek(Token![/]) - || input.peek(Token![%]) - || input.peek(Token![^]) - || input.peek(Token![>]) - || input.peek(Token![<=]) - || input.peek(Token![!=]) - || input.peek(Token![-=]) - || input.peek(Token![*=]) - || input.peek(Token![&=]) - || input.peek(Token![|=]) - || input.peek(Token![<<=]) - || input.peek(Token![as])) - { - Ok(None) - } else { - let end = parse_binop_rhs(input, allow_struct, Precedence::Range)?; - Ok(Some(end)) - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, 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 expr_style = true; - let (qself, path) = path::parsing::qpath(input, expr_style)?; - - Ok(ExprPath { attrs, qself, path }) - } - } - - #[cfg_attr(docsrs, 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")] - impl Arm { - pub(crate) fn parse_multiple(input: ParseStream) -> Result<Vec<Self>> { - let mut arms = Vec::new(); - while !input.is_empty() { - arms.push(input.call(Arm::parse)?); - } - Ok(arms) - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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 = Expr::parse_with_earlier_boundary_rule(input)?; - requires_comma = classify::requires_comma_to_be_match_arm(&body); - Box::new(body) - }, - comma: { - if requires_comma && !input.is_empty() { - Some(input.parse()?) - } else { - input.parse()? - } - }, - }) - } - } - - #[cfg_attr(docsrs, 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::PLACEHOLDER); - *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) - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] - impl Parse for PointerMutability { - fn parse(input: ParseStream) -> Result<Self> { - let lookahead = input.lookahead1(); - if lookahead.peek(Token![const]) { - Ok(PointerMutability::Const(input.parse()?)) - } else if lookahead.peek(Token![mut]) { - Ok(PointerMutability::Mut(input.parse()?)) - } else { - Err(lookahead.error()) - } - } - } - - 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 crate::attr::Attribute; - #[cfg(feature = "full")] - use crate::attr::FilterAttrs; - #[cfg(feature = "full")] - use crate::classify; - #[cfg(feature = "full")] - use crate::expr::{ - Arm, ExprArray, ExprAssign, ExprAsync, ExprAwait, ExprBlock, ExprBreak, ExprClosure, - ExprConst, ExprContinue, ExprForLoop, ExprIf, ExprInfer, ExprLet, ExprLoop, ExprMatch, - ExprRange, ExprRawAddr, ExprRepeat, ExprReturn, ExprTry, ExprTryBlock, ExprUnsafe, - ExprWhile, ExprYield, Label, PointerMutability, RangeLimits, - }; - use crate::expr::{ - Expr, ExprBinary, ExprCall, ExprCast, ExprField, ExprGroup, ExprIndex, ExprLit, ExprMacro, - ExprMethodCall, ExprParen, ExprPath, ExprReference, ExprStruct, ExprTuple, ExprUnary, - FieldValue, Index, Member, - }; - use crate::fixup::FixupContext; - use crate::op::BinOp; - use crate::path; - use crate::path::printing::PathStyle; - use crate::precedence::Precedence; - use crate::token; - #[cfg(feature = "full")] - use crate::ty::ReturnType; - use proc_macro2::{Literal, Span, TokenStream}; - use quote::{ToTokens, TokenStreamExt}; - - #[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) {} - - pub(crate) fn print_subexpression( - expr: &Expr, - needs_group: bool, - tokens: &mut TokenStream, - mut fixup: FixupContext, - ) { - if needs_group { - // If we are surrounding the whole cond in parentheses, such as: - // - // if (return Struct {}) {} - // - // then there is no need for parenthesizing the individual struct - // expressions within. On the other hand if the whole cond is not - // parenthesized, then print_expr must parenthesize exterior struct - // literals. - // - // if x == (Struct {}) {} - // - fixup = FixupContext::NONE; - } - - let do_print_expr = |tokens: &mut TokenStream| print_expr(expr, tokens, fixup); - - if needs_group { - token::Paren::default().surround(tokens, do_print_expr); - } else { - do_print_expr(tokens); - } - } - - pub(crate) fn print_expr(expr: &Expr, tokens: &mut TokenStream, mut fixup: FixupContext) { - #[cfg(feature = "full")] - let needs_group = fixup.parenthesize(expr); - #[cfg(not(feature = "full"))] - let needs_group = false; - - if needs_group { - fixup = FixupContext::NONE; - } - - let do_print_expr = |tokens: &mut TokenStream| match expr { - #[cfg(feature = "full")] - Expr::Array(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Assign(e) => print_expr_assign(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::Async(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Await(e) => print_expr_await(e, tokens, fixup), - Expr::Binary(e) => print_expr_binary(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::Block(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Break(e) => print_expr_break(e, tokens, fixup), - Expr::Call(e) => print_expr_call(e, tokens, fixup), - Expr::Cast(e) => print_expr_cast(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::Closure(e) => print_expr_closure(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::Const(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Continue(e) => e.to_tokens(tokens), - Expr::Field(e) => print_expr_field(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::ForLoop(e) => e.to_tokens(tokens), - Expr::Group(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::If(e) => e.to_tokens(tokens), - Expr::Index(e) => print_expr_index(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::Infer(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Let(e) => print_expr_let(e, tokens, fixup), - Expr::Lit(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Loop(e) => e.to_tokens(tokens), - Expr::Macro(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Match(e) => e.to_tokens(tokens), - Expr::MethodCall(e) => print_expr_method_call(e, tokens, fixup), - Expr::Paren(e) => e.to_tokens(tokens), - Expr::Path(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Range(e) => print_expr_range(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::RawAddr(e) => print_expr_raw_addr(e, tokens, fixup), - Expr::Reference(e) => print_expr_reference(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::Repeat(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Return(e) => print_expr_return(e, tokens, fixup), - Expr::Struct(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Try(e) => print_expr_try(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::TryBlock(e) => e.to_tokens(tokens), - Expr::Tuple(e) => e.to_tokens(tokens), - Expr::Unary(e) => print_expr_unary(e, tokens, fixup), - #[cfg(feature = "full")] - Expr::Unsafe(e) => e.to_tokens(tokens), - Expr::Verbatim(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::While(e) => e.to_tokens(tokens), - #[cfg(feature = "full")] - Expr::Yield(e) => print_expr_yield(e, tokens, fixup), - - #[cfg(not(feature = "full"))] - _ => unreachable!(), - }; - - if needs_group { - token::Paren::default().surround(tokens, do_print_expr); - } else { - do_print_expr(tokens); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprAssign { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_assign(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_assign(e: &ExprAssign, tokens: &mut TokenStream, mut fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - - let needs_group = !e.attrs.is_empty(); - if needs_group { - fixup = FixupContext::NONE; - } - - let do_print_expr = |tokens: &mut TokenStream| { - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_operator( - &e.left, - false, - false, - Precedence::Assign, - ); - print_subexpression(&e.left, left_prec <= Precedence::Range, tokens, left_fixup); - e.eq_token.to_tokens(tokens); - print_expr( - &e.right, - tokens, - fixup.rightmost_subexpression_fixup(false, false, Precedence::Assign), - ); - }; - - if needs_group { - token::Paren::default().surround(tokens, do_print_expr); - } else { - do_print_expr(tokens); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprAwait { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_await(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_await(e: &ExprAwait, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_dot(&e.base); - print_subexpression( - &e.base, - left_prec < Precedence::Unambiguous, - tokens, - left_fixup, - ); - e.dot_token.to_tokens(tokens); - e.await_token.to_tokens(tokens); - } - - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprBinary { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_binary(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_binary(e: &ExprBinary, tokens: &mut TokenStream, mut fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - - let needs_group = !e.attrs.is_empty(); - if needs_group { - fixup = FixupContext::NONE; - } - - let do_print_expr = |tokens: &mut TokenStream| { - let binop_prec = Precedence::of_binop(&e.op); - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_operator( - &e.left, - #[cfg(feature = "full")] - match &e.op { - BinOp::Sub(_) - | BinOp::Mul(_) - | BinOp::And(_) - | BinOp::Or(_) - | BinOp::BitAnd(_) - | BinOp::BitOr(_) - | BinOp::Shl(_) - | BinOp::Lt(_) => true, - _ => false, - }, - match &e.op { - BinOp::Shl(_) | BinOp::Lt(_) => true, - _ => false, - }, - #[cfg(feature = "full")] - binop_prec, - ); - let left_needs_group = match binop_prec { - Precedence::Assign => left_prec <= Precedence::Range, - Precedence::Compare => left_prec <= binop_prec, - _ => left_prec < binop_prec, - }; - - let right_fixup = fixup.rightmost_subexpression_fixup( - #[cfg(feature = "full")] - false, - #[cfg(feature = "full")] - false, - #[cfg(feature = "full")] - binop_prec, - ); - let right_needs_group = binop_prec != Precedence::Assign - && right_fixup.rightmost_subexpression_precedence(&e.right) <= binop_prec; - - print_subexpression(&e.left, left_needs_group, tokens, left_fixup); - e.op.to_tokens(tokens); - print_subexpression(&e.right, right_needs_group, tokens, right_fixup); - }; - - if needs_group { - token::Paren::default().surround(tokens, do_print_expr); - } else { - do_print_expr(tokens); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprBreak { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_break(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_break(e: &ExprBreak, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.break_token.to_tokens(tokens); - e.label.to_tokens(tokens); - if let Some(value) = &e.expr { - print_subexpression( - value, - // Parenthesize `break 'inner: loop { break 'inner 1 } + 1` - // ^---------------------------------^ - e.label.is_none() && classify::expr_leading_label(value), - tokens, - fixup.rightmost_subexpression_fixup(true, true, Precedence::Jump), - ); - } - } - - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprCall { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_call(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_call(e: &ExprCall, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_operator( - &e.func, - #[cfg(feature = "full")] - true, - false, - #[cfg(feature = "full")] - Precedence::Unambiguous, - ); - let needs_group = if let Expr::Field(func) = &*e.func { - func.member.is_named() - } else { - left_prec < Precedence::Unambiguous - }; - print_subexpression(&e.func, needs_group, tokens, left_fixup); - - e.paren_token.surround(tokens, |tokens| { - e.args.to_tokens(tokens); - }); - } - - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprCast { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_cast(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_cast(e: &ExprCast, tokens: &mut TokenStream, mut fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - - let needs_group = !e.attrs.is_empty(); - if needs_group { - fixup = FixupContext::NONE; - } - - let do_print_expr = |tokens: &mut TokenStream| { - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_operator( - &e.expr, - #[cfg(feature = "full")] - false, - false, - #[cfg(feature = "full")] - Precedence::Cast, - ); - print_subexpression(&e.expr, left_prec < Precedence::Cast, tokens, left_fixup); - e.as_token.to_tokens(tokens); - e.ty.to_tokens(tokens); - }; - - if needs_group { - token::Paren::default().surround(tokens, do_print_expr); - } else { - do_print_expr(tokens); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprClosure { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_closure(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_closure(e: &ExprClosure, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.lifetimes.to_tokens(tokens); - e.constness.to_tokens(tokens); - e.movability.to_tokens(tokens); - e.asyncness.to_tokens(tokens); - e.capture.to_tokens(tokens); - e.or1_token.to_tokens(tokens); - e.inputs.to_tokens(tokens); - e.or2_token.to_tokens(tokens); - e.output.to_tokens(tokens); - if matches!(e.output, ReturnType::Default) - || matches!(&*e.body, Expr::Block(body) if body.attrs.is_empty() && body.label.is_none()) - { - print_expr( - &e.body, - tokens, - fixup.rightmost_subexpression_fixup(false, false, Precedence::Jump), - ); - } else { - token::Brace::default().surround(tokens, |tokens| { - print_expr(&e.body, tokens, FixupContext::new_stmt()); - }); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprField { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_field(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_field(e: &ExprField, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_dot(&e.base); - print_subexpression( - &e.base, - left_prec < Precedence::Unambiguous, - tokens, - left_fixup, - ); - e.dot_token.to_tokens(tokens); - e.member.to_tokens(tokens); - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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); - print_expr(&self.expr, tokens, FixupContext::new_condition()); - self.body.brace_token.surround(tokens, |tokens| { - inner_attrs_to_tokens(&self.attrs, tokens); - tokens.append_all(&self.body.stmts); - }); - } - } - - #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprIf { - fn to_tokens(&self, tokens: &mut TokenStream) { - outer_attrs_to_tokens(&self.attrs, tokens); - - let mut expr = self; - loop { - expr.if_token.to_tokens(tokens); - print_expr(&expr.cond, tokens, FixupContext::new_condition()); - expr.then_branch.to_tokens(tokens); - - let (else_token, else_) = match &expr.else_branch { - Some(else_branch) => else_branch, - None => break, - }; - - else_token.to_tokens(tokens); - match &**else_ { - Expr::If(next) => { - expr = next; - } - Expr::Block(last) => { - last.to_tokens(tokens); - break; - } - // If this is not one of the valid expressions to exist in - // an else clause, wrap it in a block. - other => { - token::Brace::default().surround(tokens, |tokens| { - print_expr(other, tokens, FixupContext::new_stmt()); - }); - break; - } - } - } - } - } - - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprIndex { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_index(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_index(e: &ExprIndex, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_operator( - &e.expr, - #[cfg(feature = "full")] - true, - false, - #[cfg(feature = "full")] - Precedence::Unambiguous, - ); - print_subexpression( - &e.expr, - left_prec < Precedence::Unambiguous, - tokens, - left_fixup, - ); - e.bracket_token.surround(tokens, |tokens| { - e.index.to_tokens(tokens); - }); - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprLet { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_let(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_let(e: &ExprLet, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.let_token.to_tokens(tokens); - e.pat.to_tokens(tokens); - e.eq_token.to_tokens(tokens); - let (right_prec, right_fixup) = fixup.rightmost_subexpression(&e.expr, Precedence::Let); - print_subexpression(&e.expr, right_prec < Precedence::Let, tokens, right_fixup); - } - - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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); - print_expr(&self.expr, tokens, FixupContext::new_condition()); - 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 - && classify::requires_comma_to_be_match_arm(&arm.body) - && arm.comma.is_none() - { - <Token![,]>::default().to_tokens(tokens); - } - } - }); - } - } - - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprMethodCall { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_method_call(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_method_call(e: &ExprMethodCall, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_dot(&e.receiver); - print_subexpression( - &e.receiver, - left_prec < Precedence::Unambiguous, - tokens, - left_fixup, - ); - e.dot_token.to_tokens(tokens); - e.method.to_tokens(tokens); - if let Some(turbofish) = &e.turbofish { - path::printing::print_angle_bracketed_generic_arguments( - tokens, - turbofish, - PathStyle::Expr, - ); - } - e.paren_token.surround(tokens, |tokens| { - e.args.to_tokens(tokens); - }); - } - - #[cfg_attr(docsrs, 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(docsrs, 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_qpath(tokens, &self.qself, &self.path, PathStyle::Expr); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprRange { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_range(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_range(e: &ExprRange, tokens: &mut TokenStream, mut fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - - let needs_group = !e.attrs.is_empty(); - if needs_group { - fixup = FixupContext::NONE; - } - - let do_print_expr = |tokens: &mut TokenStream| { - if let Some(start) = &e.start { - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_operator( - start, - true, - false, - Precedence::Range, - ); - print_subexpression(start, left_prec <= Precedence::Range, tokens, left_fixup); - } - e.limits.to_tokens(tokens); - if let Some(end) = &e.end { - let right_fixup = - fixup.rightmost_subexpression_fixup(false, true, Precedence::Range); - let right_prec = right_fixup.rightmost_subexpression_precedence(end); - print_subexpression(end, right_prec <= Precedence::Range, tokens, right_fixup); - } - }; - - if needs_group { - token::Paren::default().surround(tokens, do_print_expr); - } else { - do_print_expr(tokens); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprRawAddr { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_raw_addr(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_raw_addr(e: &ExprRawAddr, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.and_token.to_tokens(tokens); - e.raw.to_tokens(tokens); - e.mutability.to_tokens(tokens); - let (right_prec, right_fixup) = fixup.rightmost_subexpression(&e.expr, Precedence::Prefix); - print_subexpression( - &e.expr, - right_prec < Precedence::Prefix, - tokens, - right_fixup, - ); - } - - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprReference { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_reference(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_reference(e: &ExprReference, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.and_token.to_tokens(tokens); - e.mutability.to_tokens(tokens); - let (right_prec, right_fixup) = fixup.rightmost_subexpression( - &e.expr, - #[cfg(feature = "full")] - Precedence::Prefix, - ); - print_subexpression( - &e.expr, - right_prec < Precedence::Prefix, - tokens, - right_fixup, - ); - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprReturn { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_return(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_return(e: &ExprReturn, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.return_token.to_tokens(tokens); - if let Some(expr) = &e.expr { - print_expr( - expr, - tokens, - fixup.rightmost_subexpression_fixup(true, false, Precedence::Jump), - ); - } - } - - #[cfg_attr(docsrs, 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_qpath(tokens, &self.qself, &self.path, PathStyle::Expr); - 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprTry { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_try(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_try(e: &ExprTry, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - let (left_prec, left_fixup) = fixup.leftmost_subexpression_with_dot(&e.expr); - print_subexpression( - &e.expr, - left_prec < Precedence::Unambiguous, - tokens, - left_fixup, - ); - e.question_token.to_tokens(tokens); - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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_attr(docsrs, 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprUnary { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_unary(self, tokens, FixupContext::NONE); - } - } - - fn print_expr_unary(e: &ExprUnary, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.op.to_tokens(tokens); - let (right_prec, right_fixup) = fixup.rightmost_subexpression( - &e.expr, - #[cfg(feature = "full")] - Precedence::Prefix, - ); - print_subexpression( - &e.expr, - right_prec < Precedence::Prefix, - tokens, - right_fixup, - ); - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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(docsrs, 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); - print_expr(&self.cond, tokens, FixupContext::new_condition()); - 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(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for ExprYield { - fn to_tokens(&self, tokens: &mut TokenStream) { - print_expr_yield(self, tokens, FixupContext::NONE); - } - } - - #[cfg(feature = "full")] - fn print_expr_yield(e: &ExprYield, tokens: &mut TokenStream, fixup: FixupContext) { - outer_attrs_to_tokens(&e.attrs, tokens); - e.yield_token.to_tokens(tokens); - if let Some(expr) = &e.expr { - print_expr( - expr, - tokens, - fixup.rightmost_subexpression_fixup(true, false, Precedence::Jump), - ); - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, 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); - print_expr(&self.body, tokens, FixupContext::new_match_arm()); - self.comma.to_tokens(tokens); - } - } - - #[cfg_attr(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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(docsrs, 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), - } - } - } - - #[cfg(feature = "full")] - #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] - impl ToTokens for PointerMutability { - fn to_tokens(&self, tokens: &mut TokenStream) { - match self { - PointerMutability::Const(const_token) => const_token.to_tokens(tokens), - PointerMutability::Mut(mut_token) => mut_token.to_tokens(tokens), - } - } - } -} |