Trait formality_core::DowncastFrom

pub trait DowncastFrom<T>: Sized {
    // Required method
    fn downcast_from(t: &T) -> Option<Self>;
}

Our version of “try-from”. A “downcast” casts from a more general type (e.g., any Parameter) to a more specific type (e.g., a type). This returns an Option because the value may not be an instance of the more specific type.

Required Methods

fn downcast_from(t: &T) -> Option<Self>

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl<A, B, A1, B1> DowncastFrom<(A1, B1)> for (A, B)

where A: DowncastFrom<A1>, B: DowncastFrom<B1>,

fn downcast_from(term: &(A1, B1)) -> Option<Self>

impl<A, B, C, A1, B1, C1> DowncastFrom<(A1, B1, C1)> for (A, B, C)

where A: DowncastFrom<A1>, B: DowncastFrom<B1>, C: DowncastFrom<C1>,

fn downcast_from(term: &(A1, B1, C1)) -> Option<Self>

impl<T, U> DowncastFrom<Option<U>> for Option<T>

where T: DowncastFrom<U>,

fn downcast_from(u: &Option<U>) -> Option<Self>

impl<T, U> DowncastFrom<Arc<U>> for Arc<T>

where T: DowncastFrom<U>,

fn downcast_from(u: &Arc<U>) -> Option<Self>

Implementors

impl<A, B> DowncastFrom<BTreeSet<A>> for Set<B>

where A: Ord, B: DowncastFrom<A> + Ord,

impl<T, U> DowncastFrom<T> for U

where T: DowncastTo<U>,