#[non_exhaustive]pub enum InstanceRoleCredentialsProvider {
SharedCredentialFile,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against InstanceRoleCredentialsProvider, 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 instancerolecredentialsprovider = unimplemented!();
match instancerolecredentialsprovider {
InstanceRoleCredentialsProvider::SharedCredentialFile => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when instancerolecredentialsprovider represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant InstanceRoleCredentialsProvider::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
InstanceRoleCredentialsProvider::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 InstanceRoleCredentialsProvider::NewFeature is defined.
Specifically, when instancerolecredentialsprovider represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on InstanceRoleCredentialsProvider::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis 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
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 InstanceRoleCredentialsProvider
impl InstanceRoleCredentialsProvider
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 InstanceRoleCredentialsProvider
impl AsRef<str> for InstanceRoleCredentialsProvider
source§impl Clone for InstanceRoleCredentialsProvider
impl Clone for InstanceRoleCredentialsProvider
source§fn clone(&self) -> InstanceRoleCredentialsProvider
fn clone(&self) -> InstanceRoleCredentialsProvider
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 InstanceRoleCredentialsProvider
impl From<&str> for InstanceRoleCredentialsProvider
source§impl Ord for InstanceRoleCredentialsProvider
impl Ord for InstanceRoleCredentialsProvider
source§fn cmp(&self, other: &InstanceRoleCredentialsProvider) -> Ordering
fn cmp(&self, other: &InstanceRoleCredentialsProvider) -> 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 InstanceRoleCredentialsProvider
impl PartialEq for InstanceRoleCredentialsProvider
source§fn eq(&self, other: &InstanceRoleCredentialsProvider) -> bool
fn eq(&self, other: &InstanceRoleCredentialsProvider) -> bool
self and other values to be equal, and is used
by ==.source§impl PartialOrd for InstanceRoleCredentialsProvider
impl PartialOrd for InstanceRoleCredentialsProvider
source§fn partial_cmp(
&self,
other: &InstanceRoleCredentialsProvider
) -> Option<Ordering>
fn partial_cmp( &self, other: &InstanceRoleCredentialsProvider ) -> 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 InstanceRoleCredentialsProvider
impl StructuralEq for InstanceRoleCredentialsProvider
impl StructuralPartialEq for InstanceRoleCredentialsProvider
Auto Trait Implementations§
impl RefUnwindSafe for InstanceRoleCredentialsProvider
impl Send for InstanceRoleCredentialsProvider
impl Sync for InstanceRoleCredentialsProvider
impl Unpin for InstanceRoleCredentialsProvider
impl UnwindSafe for InstanceRoleCredentialsProvider
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.