#[non_exhaustive]pub enum ReturnItemCollectionMetrics {
None,
Size,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against ReturnItemCollectionMetrics
, 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 returnitemcollectionmetrics = unimplemented!();
match returnitemcollectionmetrics {
ReturnItemCollectionMetrics::None => { /* ... */ },
ReturnItemCollectionMetrics::Size => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when returnitemcollectionmetrics
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ReturnItemCollectionMetrics::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
ReturnItemCollectionMetrics::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 ReturnItemCollectionMetrics::NewFeature
is defined.
Specifically, when returnitemcollectionmetrics
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on ReturnItemCollectionMetrics::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
None
Size
Unknown(UnknownVariantValue)
Unknown
. See the docs on this enum for the correct way to handle unknown variants.Unknown
contains new variants that have been added since this code was generated.
Implementations§
source§impl ReturnItemCollectionMetrics
impl ReturnItemCollectionMetrics
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for ReturnItemCollectionMetrics
impl AsRef<str> for ReturnItemCollectionMetrics
source§impl Clone for ReturnItemCollectionMetrics
impl Clone for ReturnItemCollectionMetrics
source§fn clone(&self) -> ReturnItemCollectionMetrics
fn clone(&self) -> ReturnItemCollectionMetrics
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for ReturnItemCollectionMetrics
impl Debug for ReturnItemCollectionMetrics
source§impl From<&str> for ReturnItemCollectionMetrics
impl From<&str> for ReturnItemCollectionMetrics
source§impl Hash for ReturnItemCollectionMetrics
impl Hash for ReturnItemCollectionMetrics
source§impl Ord for ReturnItemCollectionMetrics
impl Ord for ReturnItemCollectionMetrics
source§fn cmp(&self, other: &ReturnItemCollectionMetrics) -> Ordering
fn cmp(&self, other: &ReturnItemCollectionMetrics) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl PartialEq for ReturnItemCollectionMetrics
impl PartialEq for ReturnItemCollectionMetrics
source§fn eq(&self, other: &ReturnItemCollectionMetrics) -> bool
fn eq(&self, other: &ReturnItemCollectionMetrics) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for ReturnItemCollectionMetrics
impl PartialOrd for ReturnItemCollectionMetrics
source§fn partial_cmp(&self, other: &ReturnItemCollectionMetrics) -> Option<Ordering>
fn partial_cmp(&self, other: &ReturnItemCollectionMetrics) -> 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 ReturnItemCollectionMetrics
impl StructuralEq for ReturnItemCollectionMetrics
impl StructuralPartialEq for ReturnItemCollectionMetrics
Auto Trait Implementations§
impl RefUnwindSafe for ReturnItemCollectionMetrics
impl Send for ReturnItemCollectionMetrics
impl Sync for ReturnItemCollectionMetrics
impl Unpin for ReturnItemCollectionMetrics
impl UnwindSafe for ReturnItemCollectionMetrics
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
§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,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§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,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.