#[non_exhaustive]pub enum ApplicationDiscoveryStatus {
Deleting,
RefreshFailed,
Registering,
RegistrationFailed,
Success,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against ApplicationDiscoveryStatus, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let applicationdiscoverystatus = unimplemented!();
match applicationdiscoverystatus {
ApplicationDiscoveryStatus::Deleting => { /* ... */ },
ApplicationDiscoveryStatus::RefreshFailed => { /* ... */ },
ApplicationDiscoveryStatus::Registering => { /* ... */ },
ApplicationDiscoveryStatus::RegistrationFailed => { /* ... */ },
ApplicationDiscoveryStatus::Success => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when applicationdiscoverystatus represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ApplicationDiscoveryStatus::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
ApplicationDiscoveryStatus::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str on it yields "NewFeature".
This match expression is forward-compatible when executed with a newer
version of SDK where the variant ApplicationDiscoveryStatus::NewFeature is defined.
Specifically, when applicationdiscoverystatus represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on ApplicationDiscoveryStatus::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
Deleting
RefreshFailed
Registering
RegistrationFailed
Success
Unknown(UnknownVariantValue)
Unknown contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for ApplicationDiscoveryStatus
impl AsRef<str> for ApplicationDiscoveryStatus
source§impl Clone for ApplicationDiscoveryStatus
impl Clone for ApplicationDiscoveryStatus
source§fn clone(&self) -> ApplicationDiscoveryStatus
fn clone(&self) -> ApplicationDiscoveryStatus
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for ApplicationDiscoveryStatus
impl Debug for ApplicationDiscoveryStatus
source§impl From<&str> for ApplicationDiscoveryStatus
impl From<&str> for ApplicationDiscoveryStatus
source§impl FromStr for ApplicationDiscoveryStatus
impl FromStr for ApplicationDiscoveryStatus
source§impl Hash for ApplicationDiscoveryStatus
impl Hash for ApplicationDiscoveryStatus
source§impl Ord for ApplicationDiscoveryStatus
impl Ord for ApplicationDiscoveryStatus
source§fn cmp(&self, other: &ApplicationDiscoveryStatus) -> Ordering
fn cmp(&self, other: &ApplicationDiscoveryStatus) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl PartialEq for ApplicationDiscoveryStatus
impl PartialEq for ApplicationDiscoveryStatus
source§fn eq(&self, other: &ApplicationDiscoveryStatus) -> bool
fn eq(&self, other: &ApplicationDiscoveryStatus) -> bool
self and other values to be equal, and is used
by ==.source§impl PartialOrd for ApplicationDiscoveryStatus
impl PartialOrd for ApplicationDiscoveryStatus
source§fn partial_cmp(&self, other: &ApplicationDiscoveryStatus) -> Option<Ordering>
fn partial_cmp(&self, other: &ApplicationDiscoveryStatus) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self and other) and is used by the <=
operator. Read moreimpl Eq for ApplicationDiscoveryStatus
impl StructuralEq for ApplicationDiscoveryStatus
impl StructuralPartialEq for ApplicationDiscoveryStatus
Auto Trait Implementations§
impl RefUnwindSafe for ApplicationDiscoveryStatus
impl Send for ApplicationDiscoveryStatus
impl Sync for ApplicationDiscoveryStatus
impl Unpin for ApplicationDiscoveryStatus
impl UnwindSafe for ApplicationDiscoveryStatus
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.