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use core::convert::Infallible;
pub trait UnwrapOptimized {
type Output;
fn unwrap_optimized(self) -> Self::Output;
}
impl<T> UnwrapOptimized for Option<T> {
type Output = T;
#[inline(always)]
fn unwrap_optimized(self) -> Self::Output {
#[cfg(target_family = "wasm")]
match self {
Some(t) => t,
None => core::arch::wasm32::unreachable(),
}
#[cfg(not(target_family = "wasm"))]
self.unwrap()
}
}
impl<T, E: core::fmt::Debug> UnwrapOptimized for Result<T, E> {
type Output = T;
#[inline(always)]
fn unwrap_optimized(self) -> Self::Output {
#[cfg(target_family = "wasm")]
match self {
Ok(t) => t,
Err(_) => core::arch::wasm32::unreachable(),
}
#[cfg(not(target_family = "wasm"))]
self.unwrap()
}
}
pub trait UnwrapInfallible {
type Output;
fn unwrap_infallible(self) -> Self::Output;
}
impl<T> UnwrapInfallible for Result<T, Infallible> {
type Output = T;
fn unwrap_infallible(self) -> Self::Output {
match self {
Ok(ok) => ok,
// In the following `Err(never)` branch we convert a type from
// `Infallible` to `!`. Both of these are empty types and are
// essentially synonyms in rust, they differ only due to historical
// reasons that will eventually be eliminated. `Infallible` is a
// version we can put in a structure, and `!` is one that gets some
// special control-flow treatments.
//
// Specifically: the type `!` of the resulting expression will be
// considered an acceptable inhabitant of any type -- including
// `Self::Output` -- since it's an impossible path to execute, this
// is considered a harmless convenience in the type system, a bit
// like defining zero-divided-by-anything as zero.
//
// We could also write an infinite `loop {}` here or
// `unreachable!()` or similar expressions of type `!`, but
// destructuring the `never` variable into an empty set of cases is
// the most honest since it's statically checked to _be_ infallible,
// not just an assertion of our hopes.)
// This allow and the Err can be removed once 1.82 becomes stable
#[allow(unreachable_patterns)]
Err(never) => match never {},
}
}
}