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