Trait core::ops::FromResidual[−][src]

pub trait FromResidual<R = Self::Residual> {
    fn from_residual(residual: R) -> Self;
}
🔬 This is a nightly-only experimental API. (try_trait_v2 #84277)
Expand description

Used to specify which residuals can be converted into which crate::ops::Try types.

Every Try type needs to be recreatable from its own associated Residual type, but can also have additional FromResidual implementations to support interconversion with other Try types.

Required methods

fn from_residual(residual: R) -> Self[src]

🔬 This is a nightly-only experimental API. (try_trait_v2 #84277)

Constructs the type from a compatible Residual type.

This should be implemented consistently with the branch method such that applying the ? operator will get back an equivalent residual: FromResidual::from_residual(r).branch() --> ControlFlow::Break(r). (It may not be an identical residual when interconversion is involved.)

Examples

#![feature(try_trait_v2)]
#![feature(control_flow_enum)]
use std::ops::{ControlFlow, FromResidual};

assert_eq!(Result::<String, i64>::from_residual(Err(3_u8)), Err(3));
assert_eq!(Option::<String>::from_residual(None), None);
assert_eq!(
    ControlFlow::<_, String>::from_residual(ControlFlow::Break(5)),
    ControlFlow::Break(5),
);
Run

Implementors

impl<B, C> FromResidual<<ControlFlow<B, C> as Try>::Residual> for ControlFlow<B, C>[src]

fn from_residual(residual: ControlFlow<B, Infallible>) -> Self[src]

🔬 This is a nightly-only experimental API. (try_trait_v2 #84277)

impl<T> FromResidual<<Option<T> as Try>::Residual> for Option<T>[src]

fn from_residual(residual: Option<Infallible>) -> Self[src]

🔬 This is a nightly-only experimental API. (try_trait_v2 #84277)

impl<T, E, F: From<E>> FromResidual<Result<Infallible, E>> for Result<T, F>[src]

fn from_residual(residual: Result<Infallible, E>) -> Self[src]

🔬 This is a nightly-only experimental API. (try_trait_v2 #84277)

impl<T, E, F: From<E>> FromResidual<Result<Infallible, E>> for Poll<Option<Result<T, F>>>[src]

fn from_residual(x: Result<Infallible, E>) -> Self[src]

🔬 This is a nightly-only experimental API. (try_trait_v2 #84277)

impl<T, E, F: From<E>> FromResidual<Result<Infallible, E>> for Poll<Result<T, F>>[src]

fn from_residual(x: Result<Infallible, E>) -> Self[src]

🔬 This is a nightly-only experimental API. (try_trait_v2 #84277)