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