Enum rustc_ast::ast::ExprKind

pub enum ExprKind {
    Array(ThinVec<P<Expr>>),
    ConstBlock(AnonConst),
    Call(P<Expr>, ThinVec<P<Expr>>),
    MethodCall(Box<MethodCall>),
    Tup(ThinVec<P<Expr>>),
    Binary(BinOp, P<Expr>, P<Expr>),
    Unary(UnOp, P<Expr>),
    Lit(Lit),
    Cast(P<Expr>, P<Ty>),
    Type(P<Expr>, P<Ty>),
    Let(P<Pat>, P<Expr>, Span, Recovered),
    If(P<Expr>, P<Block>, Option<P<Expr>>),
    While(P<Expr>, P<Block>, Option<Label>),
    ForLoop {
        pat: P<Pat>,
        iter: P<Expr>,
        body: P<Block>,
        label: Option<Label>,
        kind: ForLoopKind,
    },
    Loop(P<Block>, Option<Label>, Span),
    Match(P<Expr>, ThinVec<Arm>, MatchKind),
    Closure(Box<Closure>),
    Block(P<Block>, Option<Label>),
    Gen(CaptureBy, P<Block>, GenBlockKind, Span),
    Await(P<Expr>, Span),
    TryBlock(P<Block>),
    Assign(P<Expr>, P<Expr>, Span),
    AssignOp(BinOp, P<Expr>, P<Expr>),
    Field(P<Expr>, Ident),
    Index(P<Expr>, P<Expr>, Span),
    Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits),
    Underscore,
    Path(Option<P<QSelf>>, Path),
    AddrOf(BorrowKind, Mutability, P<Expr>),
    Break(Option<Label>, Option<P<Expr>>),
    Continue(Option<Label>),
    Ret(Option<P<Expr>>),
    InlineAsm(P<InlineAsm>),
    OffsetOf(P<Ty>, P<[Ident]>),
    MacCall(P<MacCall>),
    Struct(P<StructExpr>),
    Repeat(P<Expr>, AnonConst),
    Paren(P<Expr>),
    Try(P<Expr>),
    Yield(Option<P<Expr>>),
    Yeet(Option<P<Expr>>),
    Become(P<Expr>),
    IncludedBytes(Lrc<[u8]>),
    FormatArgs(P<FormatArgs>),
    Err(ErrorGuaranteed),
    Dummy,
}

Variants

Array(ThinVec<P<Expr>>)

An array (e.g, [a, b, c, d]).

ConstBlock(AnonConst)

Allow anonymous constants from an inline const block.

Call(P<Expr>, ThinVec<P<Expr>>)

A function call.

The first field resolves to the function itself, and the second field is the list of arguments. This also represents calling the constructor of tuple-like ADTs such as tuple structs and enum variants.

MethodCall(Box<MethodCall>)

A method call (e.g., x.foo::<Bar, Baz>(a, b, c)).

Tup(ThinVec<P<Expr>>)

A tuple (e.g., (a, b, c, d)).

Binary(BinOp, P<Expr>, P<Expr>)

A binary operation (e.g., a + b, a * b).

Unary(UnOp, P<Expr>)

A unary operation (e.g., !x, *x).

Lit(Lit)

A literal (e.g., 1, "foo").

Cast(P<Expr>, P<Ty>)

A cast (e.g., foo as f64).

Type(P<Expr>, P<Ty>)

A type ascription (e.g., builtin # type_ascribe(42, usize)).

Usually not written directly in user code but indirectly via the macro type_ascribe!(...).

Let(P<Pat>, P<Expr>, Span, Recovered)

A let pat = expr expression that is only semantically allowed in the condition of if / while expressions. (e.g., if let 0 = x { .. }).

Span represents the whole let pat = expr statement.

If(P<Expr>, P<Block>, Option<P<Expr>>)

An if block, with an optional else block.

if expr { block } else { expr }

While(P<Expr>, P<Block>, Option<Label>)

A while loop, with an optional label.

'label: while expr { block }

ForLoop

A for loop, with an optional label.

'label: for await? pat in iter { block }

This is desugared to a combination of loop and match expressions.

Fields

pat: P<Pat>

iter: P<Expr>

body: P<Block>

label: Option<Label>

kind: ForLoopKind

Loop(P<Block>, Option<Label>, Span)

Conditionless loop (can be exited with break, continue, or return).

'label: loop { block }

Match(P<Expr>, ThinVec<Arm>, MatchKind)

A match block.

Closure(Box<Closure>)

A closure (e.g., move |a, b, c| a + b + c).

Block(P<Block>, Option<Label>)

A block ('label: { ... }).

Gen(CaptureBy, P<Block>, GenBlockKind, Span)

An async block (async move { ... }), or a gen block (gen move { ... }).

The span is the “decl”, which is the header before the body { } including the asyng/gen keywords and possibly move.

Await(P<Expr>, Span)

An await expression (my_future.await). Span is of await keyword.

TryBlock(P<Block>)

A try block (try { ... }).

Assign(P<Expr>, P<Expr>, Span)

An assignment (a = foo()). The Span argument is the span of the = token.

AssignOp(BinOp, P<Expr>, P<Expr>)

An assignment with an operator.

E.g., a += 1.

Field(P<Expr>, Ident)

Access of a named (e.g., obj.foo) or unnamed (e.g., obj.0) struct field.

Index(P<Expr>, P<Expr>, Span)

An indexing operation (e.g., foo[2]). The span represents the span of the [2], including brackets.

Range(Option<P<Expr>>, Option<P<Expr>>, RangeLimits)

A range (e.g., 1..2, 1.., ..2, 1..=2, ..=2; and .. in destructuring assignment).

Underscore

An underscore, used in destructuring assignment to ignore a value.

Path(Option<P<QSelf>>, Path)

Variable reference, possibly containing :: and/or type parameters (e.g., foo::bar::<baz>).

Optionally “qualified” (e.g., <Vec<T> as SomeTrait>::SomeType).

AddrOf(BorrowKind, Mutability, P<Expr>)

A referencing operation (&a, &mut a, &raw const a or &raw mut a).

Break(Option<Label>, Option<P<Expr>>)

A break, with an optional label to break, and an optional expression.

Continue(Option<Label>)

A continue, with an optional label.

Ret(Option<P<Expr>>)

A return, with an optional value to be returned.

InlineAsm(P<InlineAsm>)

Output of the asm!() macro.

OffsetOf(P<Ty>, P<[Ident]>)

An offset_of expression (e.g., builtin # offset_of(Struct, field)).

Usually not written directly in user code but indirectly via the macro core::mem::offset_of!(...).

MacCall(P<MacCall>)

A macro invocation; pre-expansion.

Struct(P<StructExpr>)

A struct literal expression.

E.g., Foo {x: 1, y: 2}, or Foo {x: 1, .. rest}.

Repeat(P<Expr>, AnonConst)

An array literal constructed from one repeated element.

E.g., [1; 5]. The expression is the element to be repeated; the constant is the number of times to repeat it.

Paren(P<Expr>)

No-op: used solely so we can pretty-print faithfully.

Try(P<Expr>)

A try expression (expr?).

Yield(Option<P<Expr>>)

A yield, with an optional value to be yielded.

Yeet(Option<P<Expr>>)

A do yeet (aka throw/fail/bail/raise/whatever), with an optional value to be returned.

Become(P<Expr>)

A tail call return, with the value to be returned.

While .0 must be a function call, we check this later, after parsing.

IncludedBytes(Lrc<[u8]>)

Bytes included via include_bytes! Added for optimization purposes to avoid the need to escape large binary blobs - should always behave like ExprKind::Lit with a ByteStr literal.

FormatArgs(P<FormatArgs>)

A format_args!() expression.

Err(ErrorGuaranteed)

Placeholder for an expression that wasn’t syntactically well formed in some way.

Dummy

Acts as a null expression. Lowering it will always emit a bug.

Trait Implementations

impl Clone for ExprKind

fn clone(&self) -> ExprKind

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ExprKind

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<__D: SpanDecoder> Decodable<__D> for ExprKind

fn decode(__decoder: &mut __D) -> Self

impl<__E: SpanEncoder> Encodable<__E> for ExprKind

fn encode(&self, __encoder: &mut __E)

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 40 bytes

Size for each variant:

• Array: 15 bytes
• ConstBlock: 23 bytes
• Call: 23 bytes
• MethodCall: 15 bytes
• Tup: 15 bytes
• Binary: 31 bytes
• Unary: 15 bytes
• Lit: 15 bytes
• Cast: 23 bytes
• Type: 23 bytes
• Let: 31 bytes
• If: 31 bytes
• While: 31 bytes
• ForLoop: 39 bytes
• Loop: 31 bytes
• Match: 23 bytes
• Closure: 15 bytes
• Block: 23 bytes
• Gen: 31 bytes
• Await: 23 bytes
• TryBlock: 15 bytes
• Assign: 31 bytes
• AssignOp: 31 bytes
• Field: 23 bytes
• Index: 31 bytes
• Range: 23 bytes
• Underscore: 0 bytes
• Path: 39 bytes
• AddrOf: 15 bytes
• Break: 23 bytes
• Continue: 15 bytes
• Ret: 15 bytes
• InlineAsm: 15 bytes
• OffsetOf: 31 bytes
• MacCall: 15 bytes
• Struct: 15 bytes
• Repeat: 31 bytes
• Paren: 15 bytes
• Try: 15 bytes
• Yield: 15 bytes
• Yeet: 15 bytes
• Become: 15 bytes
• IncludedBytes: 23 bytes
• FormatArgs: 15 bytes
• Err: 0 bytes
• Dummy: 0 bytes