#[non_exhaustive]pub enum AsyncNotificationTopicTypes {
ErrorNotificationTopic,
SuccessNotificationTopic,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against AsyncNotificationTopicTypes
, 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 asyncnotificationtopictypes = unimplemented!();
match asyncnotificationtopictypes {
AsyncNotificationTopicTypes::ErrorNotificationTopic => { /* ... */ },
AsyncNotificationTopicTypes::SuccessNotificationTopic => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when asyncnotificationtopictypes
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant AsyncNotificationTopicTypes::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
AsyncNotificationTopicTypes::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 AsyncNotificationTopicTypes::NewFeature
is defined.
Specifically, when asyncnotificationtopictypes
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on AsyncNotificationTopicTypes::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is 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
ErrorNotificationTopic
SuccessNotificationTopic
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for AsyncNotificationTopicTypes
impl AsRef<str> for AsyncNotificationTopicTypes
source§impl Clone for AsyncNotificationTopicTypes
impl Clone for AsyncNotificationTopicTypes
source§fn clone(&self) -> AsyncNotificationTopicTypes
fn clone(&self) -> AsyncNotificationTopicTypes
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for AsyncNotificationTopicTypes
impl Debug for AsyncNotificationTopicTypes
source§impl From<&str> for AsyncNotificationTopicTypes
impl From<&str> for AsyncNotificationTopicTypes
source§impl Hash for AsyncNotificationTopicTypes
impl Hash for AsyncNotificationTopicTypes
source§impl Ord for AsyncNotificationTopicTypes
impl Ord for AsyncNotificationTopicTypes
source§fn cmp(&self, other: &AsyncNotificationTopicTypes) -> Ordering
fn cmp(&self, other: &AsyncNotificationTopicTypes) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl PartialEq<AsyncNotificationTopicTypes> for AsyncNotificationTopicTypes
impl PartialEq<AsyncNotificationTopicTypes> for AsyncNotificationTopicTypes
source§fn eq(&self, other: &AsyncNotificationTopicTypes) -> bool
fn eq(&self, other: &AsyncNotificationTopicTypes) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<AsyncNotificationTopicTypes> for AsyncNotificationTopicTypes
impl PartialOrd<AsyncNotificationTopicTypes> for AsyncNotificationTopicTypes
source§fn partial_cmp(&self, other: &AsyncNotificationTopicTypes) -> Option<Ordering>
fn partial_cmp(&self, other: &AsyncNotificationTopicTypes) -> 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 AsyncNotificationTopicTypes
impl StructuralEq for AsyncNotificationTopicTypes
impl StructuralPartialEq for AsyncNotificationTopicTypes
Auto Trait Implementations§
impl RefUnwindSafe for AsyncNotificationTopicTypes
impl Send for AsyncNotificationTopicTypes
impl Sync for AsyncNotificationTopicTypes
impl Unpin for AsyncNotificationTopicTypes
impl UnwindSafe for AsyncNotificationTopicTypes
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
source§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,
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.