Struct Arm 

pub struct Arm {
    pub pattern: Pattern,
    pub guard: Option<Core>,
    pub body: Core,
    pub span: Span,
}

One arm of a match. Patterns are shallow — a constructor and its named field binders — which is what §3.1’s exhaustiveness check needs and no more.

Fields

pattern: Pattern

guard: Option<Core>

case Circle(r) if r > 0: — a condition on the arm, in the scope of what the pattern bound.

A guard that fails falls through to the next arm, which is what makes it a guard rather than an if in the body.

body: Core

span: Span

Implementations

impl Arm

pub fn exprs(&self) -> impl Iterator<Item = &Core>

Every expression this arm holds, in the order they run.

One method rather than &a.body at each of fourteen call sites, for Pattern::binders’s reason and with its history: a guard added as a field those sites did not know about would be a Core that liveness never marks, that frames never counts a slot for, and that the plan’s free-variable analysis never sees — none of which is a compile error, and all of which are wrong on a program that uses one.

pub fn exprs_mut(&mut self) -> impl Iterator<Item = &mut Core>

Trait Implementations

impl Clone for Arm

fn clone(&self) -> Arm

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Arm

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

Formats the value using the given formatter.