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