#[non_exhaustive]
pub enum ReturnValuesOnConditionCheckFailure {
AllOld,
None,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against ReturnValuesOnConditionCheckFailure
, 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 returnvaluesonconditioncheckfailure = unimplemented!();
match returnvaluesonconditioncheckfailure {
ReturnValuesOnConditionCheckFailure::AllOld => { /* ... */ },
ReturnValuesOnConditionCheckFailure::None => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when returnvaluesonconditioncheckfailure
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ReturnValuesOnConditionCheckFailure::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
ReturnValuesOnConditionCheckFailure::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 ReturnValuesOnConditionCheckFailure::NewFeature
is defined.
Specifically, when returnvaluesonconditioncheckfailure
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on ReturnValuesOnConditionCheckFailure::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
AllOld
None
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl Clone for ReturnValuesOnConditionCheckFailure
impl Clone for ReturnValuesOnConditionCheckFailure
source§fn clone(&self) -> ReturnValuesOnConditionCheckFailure
fn clone(&self) -> ReturnValuesOnConditionCheckFailure
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 ReturnValuesOnConditionCheckFailure
impl From<&str> for ReturnValuesOnConditionCheckFailure
source§impl Ord for ReturnValuesOnConditionCheckFailure
impl Ord for ReturnValuesOnConditionCheckFailure
source§fn cmp(&self, other: &ReturnValuesOnConditionCheckFailure) -> Ordering
fn cmp(&self, other: &ReturnValuesOnConditionCheckFailure) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<ReturnValuesOnConditionCheckFailure> for ReturnValuesOnConditionCheckFailure
impl PartialEq<ReturnValuesOnConditionCheckFailure> for ReturnValuesOnConditionCheckFailure
source§fn eq(&self, other: &ReturnValuesOnConditionCheckFailure) -> bool
fn eq(&self, other: &ReturnValuesOnConditionCheckFailure) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<ReturnValuesOnConditionCheckFailure> for ReturnValuesOnConditionCheckFailure
impl PartialOrd<ReturnValuesOnConditionCheckFailure> for ReturnValuesOnConditionCheckFailure
source§fn partial_cmp(
&self,
other: &ReturnValuesOnConditionCheckFailure
) -> Option<Ordering>
fn partial_cmp(
&self,
other: &ReturnValuesOnConditionCheckFailure
) -> 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 ReturnValuesOnConditionCheckFailure
impl StructuralEq for ReturnValuesOnConditionCheckFailure
impl StructuralPartialEq for ReturnValuesOnConditionCheckFailure
Auto Trait Implementations§
impl RefUnwindSafe for ReturnValuesOnConditionCheckFailure
impl Send for ReturnValuesOnConditionCheckFailure
impl Sync for ReturnValuesOnConditionCheckFailure
impl Unpin for ReturnValuesOnConditionCheckFailure
impl UnwindSafe for ReturnValuesOnConditionCheckFailure
Blanket Implementations§
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.