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