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