Enum otter_api_tests::shapelib::Infallible 1.34.0[−][src]
pub enum Infallible {}
The error type for errors that can never happen.
Since this enum has no variant, a value of this type can never actually exist.
This can be useful for generic APIs that use Result
and parameterize the error type,
to indicate that the result is always Ok
.
For example, the TryFrom
trait (conversion that returns a Result
)
has a blanket implementation for all types where a reverse Into
implementation exists.
impl<T, U> TryFrom<U> for T where U: Into<T> { type Error = Infallible; fn try_from(value: U) -> Result<Self, Infallible> { Ok(U::into(value)) // Never returns `Err` } }
Future compatibility
This enum has the same role as the !
“never” type,
which is unstable in this version of Rust.
When !
is stabilized, we plan to make Infallible
a type alias to it:
pub type Infallible = !;
… and eventually deprecate Infallible
.
However there is one case where !
syntax can be used
before !
is stabilized as a full-fledged type: in the position of a function’s return type.
Specifically, it is possible implementations for two different function pointer types:
trait MyTrait {} impl MyTrait for fn() -> ! {} impl MyTrait for fn() -> std::convert::Infallible {}
With Infallible
being an enum, this code is valid.
However when Infallible
becomes an alias for the never type,
the two impl
s will start to overlap
and therefore will be disallowed by the language’s trait coherence rules.
Trait Implementations
impl Clone for Infallible
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pub fn clone(&self) -> Infallible
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pub fn clone_from(&mut self, source: &Self)
1.0.0[src]
impl<T> Context<T, Infallible> for Option<T>
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use anyhow::{Context, Result}; fn maybe_get() -> Option<T> { ... } fn demo() -> Result<()> { let t = maybe_get().context("there is no T")?; ... }
pub fn context<C>(self, context: C) -> Result<T, Error> where
C: Display + Send + Sync + 'static,
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C: Display + Send + Sync + 'static,
pub fn with_context<C, F>(self, context: F) -> Result<T, Error> where
C: Display + Send + Sync + 'static,
F: FnOnce() -> C,
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C: Display + Send + Sync + 'static,
F: FnOnce() -> C,
impl Copy for Infallible
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impl Debug for Infallible
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impl Display for Infallible
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impl EmptyType for Infallible
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impl<T> Enum<T> for Infallible
type Array = [T; 0]
Representation of an enum map for type V
.
pub fn from_usize(usize) -> Infallible
pub fn into_usize(self) -> usize
impl Eq for Infallible
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impl Error for Infallible
1.8.0[src]
pub fn description(&self) -> &str
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pub fn source(&self) -> Option<&(dyn Error + 'static)>
1.30.0[src]
pub fn backtrace(&self) -> Option<&Backtrace>
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pub fn cause(&self) -> Option<&dyn Error>
1.0.0[src]
impl From<!> for Infallible
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pub fn from(x: !) -> Infallible
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impl From<Infallible> for TryFromSliceError
1.36.0[src]
pub fn from(x: Infallible) -> TryFromSliceError
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impl From<Infallible> for TryFromIntError
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pub fn from(x: Infallible) -> TryFromIntError
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impl Hash for Infallible
1.44.0[src]
pub fn hash<H>(&self, &mut H) where
H: Hasher,
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H: Hasher,
pub fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
impl Ord for Infallible
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pub fn cmp(&self, _other: &Infallible) -> Ordering
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#[must_use]pub fn max(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn min(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self
1.50.0[src]
impl PartialEq<Infallible> for Infallible
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pub fn eq(&self, &Infallible) -> bool
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#[must_use]pub fn ne(&self, other: &Rhs) -> bool
1.0.0[src]
impl PartialOrd<Infallible> for Infallible
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pub fn partial_cmp(&self, _other: &Infallible) -> Option<Ordering>
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#[must_use]pub fn lt(&self, other: &Rhs) -> bool
1.0.0[src]
#[must_use]pub fn le(&self, other: &Rhs) -> bool
1.0.0[src]
#[must_use]pub fn gt(&self, other: &Rhs) -> bool
1.0.0[src]
#[must_use]pub fn ge(&self, other: &Rhs) -> bool
1.0.0[src]
Auto Trait Implementations
impl RefUnwindSafe for Infallible
impl Send for Infallible
impl Sync for Infallible
impl Unpin for Infallible
impl UnwindSafe for Infallible
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> AsFail for T where
T: Fail,
T: Fail,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
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Notable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
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Notable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
impl<T> Downcast for T where
T: Any,
T: Any,
pub fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>ⓘNotable traits for Box<R, Global>
impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<F, A> Future for Box<F, A> where
A: Allocator + 'static,
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
A: Allocator,
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;
Notable traits for Box<R, Global>
impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<F, A> Future for Box<F, A> where
A: Allocator + 'static,
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
A: Allocator,
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;
pub fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
pub fn as_any(&self) -> &(dyn Any + 'static)
pub fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
impl<T> DowncastSync for T where
T: Any + Send + Sync,
T: Any + Send + Sync,
impl<A> DynCastExt for A
pub fn dyn_cast<T>(
self
) -> Result<<A as DynCastExtHelper<T>>::Target, <A as DynCastExtHelper<T>>::Source> where
T: ?Sized,
A: DynCastExtHelper<T>,
self
) -> Result<<A as DynCastExtHelper<T>>::Target, <A as DynCastExtHelper<T>>::Source> where
T: ?Sized,
A: DynCastExtHelper<T>,
pub fn dyn_upcast<T>(self) -> <A as DynCastExtAdvHelper<T, T>>::Target where
T: ?Sized,
A: DynCastExtAdvHelper<T, T, Source = <A as DynCastExtAdvHelper<T, T>>::Target>,
T: ?Sized,
A: DynCastExtAdvHelper<T, T, Source = <A as DynCastExtAdvHelper<T, T>>::Target>,
pub fn dyn_cast_adv<F, T>(
self
) -> Result<<A as DynCastExtAdvHelper<F, T>>::Target, <A as DynCastExtAdvHelper<F, T>>::Source> where
T: ?Sized,
A: DynCastExtAdvHelper<F, T>,
F: ?Sized,
self
) -> Result<<A as DynCastExtAdvHelper<F, T>>::Target, <A as DynCastExtAdvHelper<F, T>>::Source> where
T: ?Sized,
A: DynCastExtAdvHelper<F, T>,
F: ?Sized,
pub fn dyn_cast_with_config<C>(
self
) -> Result<<A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Target, <A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Source> where
C: DynCastConfig,
A: DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>,
self
) -> Result<<A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Target, <A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Source> where
C: DynCastConfig,
A: DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>,
impl<E> Fail for E where
E: 'static + Error + Send + Sync,
E: 'static + Error + Send + Sync,
pub fn name(&self) -> Option<&str>
pub fn cause(&self) -> Option<&(dyn Fail + 'static)>
pub fn backtrace(&self) -> Option<&Backtrace>
pub fn context<D>(self, context: D) -> Context<D> where
D: Display + Send + Sync + 'static,
D: Display + Send + Sync + 'static,
pub fn compat(self) -> Compat<Self>
impl<T> From<!> for T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> OrdExt<T> for T where
T: Ord + Clone,
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T: Ord + Clone,
pub fn update_max(&mut self, new: &T)
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impl<T> RuleType for T where
T: Copy + Debug + Eq + Hash + Ord,
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T: Copy + Debug + Eq + Hash + Ord,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn clone_into(&self, target: &mut T)
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impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<V, T> VZip<V> for T where
V: MultiLane<T>,
V: MultiLane<T>,