# Enum rustc_lint_defs::Level

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    pub enum Level {
        Allow,
        Expect(LintExpectationId),
        Warn,
        ForceWarn(Option<LintExpectationId>),
        Deny,
        Forbid,
    }

Expand description

Setting for how to handle a lint.

See: https://doc.rust-lang.org/rustc/lints/levels.html

## Variants§

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### Allow

The `allow` level will not issue any message.

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### Expect(LintExpectationId)

The `expect` level will suppress the lint message but in turn produce a message if the lint wasn’t issued in the expected scope. `Expect` should not be used as an initial level for a lint.

Note that this still means that the lint is enabled in this position and should be emitted, this will in turn fulfill the expectation and suppress the lint.

See RFC 2383.

The `LintExpectationId` is used to later link a lint emission to the actual expectation. It can be ignored in most cases.

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### Warn

The `warn` level will produce a warning if the lint was violated, however the compiler will continue with its execution.

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### ForceWarn(Option<LintExpectationId>)

This lint level is a special case of `Warn`, that can’t be overridden. This is used to ensure that a lint can’t be suppressed. This lint level can currently only be set via the console and is therefore session specific.

The `LintExpectationId` is intended to fulfill expectations marked via the `#[expect]` attribute, that will still be suppressed due to the level.

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### Deny

The `deny` level will produce an error and stop further execution after the lint pass is complete.

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### Forbid

`Forbid` is equivalent to the `deny` level but can’t be overwritten like the previous levels.

## Implementations§

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### impl Level

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#### pub fn as_str(self) -> &'static str

Converts a level to a lower-case string.

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#### pub fn from_str(x: &str) -> Option<Self>

Converts a lower-case string to a level. This will never construct the expect level as that would require a `LintExpectationId`.

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#### pub fn from_attr(attr: &Attribute) -> Option<Self>

Converts an `Attribute` to a level.

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#### pub fn from_symbol(s: Symbol, id: Option<AttrId>) -> Option<Self>

Converts a `Symbol` to a level.

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#### pub fn to_cmd_flag(self) -> &'static str

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#### pub fn is_error(self) -> bool

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#### pub fn get_expectation_id(&self) -> Option<LintExpectationId>

## Trait Implementations§

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### impl Clone for Level

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#### fn clone(&self) -> Level

Returns a copy of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for Level

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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### impl Hash for Level

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#### fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given `Hasher`. Read more
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#### fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given `Hasher`. Read more
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### impl<__CTX> HashStable<__CTX> for Level
where __CTX: HashStableContext,

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#### fn hash_stable(&self, __hcx: &mut __CTX, __hasher: &mut StableHasher)

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### impl Ord for Level

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#### fn cmp(&self, other: &Level) -> Ordering

This method returns an `Ordering` between `self` and `other`. Read more
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#### fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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#### fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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#### fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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### impl PartialEq for Level

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#### fn eq(&self, other: &Level) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
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#### fn ne(&self, other: &Rhs) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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### impl PartialOrd for Level

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#### fn partial_cmp(&self, other: &Level) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
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#### fn lt(&self, other: &Rhs) -> bool

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more
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#### fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
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#### fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
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#### fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
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### impl Copy for Level

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### impl Eq for Level

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### impl StructuralPartialEq for Level

## Auto Trait Implementations§

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### impl DynSend for Level

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### impl DynSync for Level

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### impl Freeze for Level

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### impl RefUnwindSafe for Level

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### impl Send for Level

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### impl Sync for Level

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### impl Unpin for Level

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### impl UnwindSafe for Level

## Blanket Implementations§

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### impl<T> Aligned for T

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#### const ALIGN: Alignment = _

Alignment of `Self`.
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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> AnyEq for T
where T: Any + PartialEq,

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#### fn equals(&self, other: &(dyn Any + 'static)) -> bool

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#### fn as_any(&self) -> &(dyn Any + 'static)

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### impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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#### fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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#### fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T> ) -> &'a mut [T]

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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<Q, K> Comparable<K> for Q
where Q: Ord + ?Sized, K: Borrow<Q> + ?Sized,

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#### fn compare(&self, key: &K) -> Ordering

Compare self to `key` and return their ordering.
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### impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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#### fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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### impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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#### fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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### impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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#### fn equivalent(&self, key: &K) -> bool

Compare self to `key` and return `true` if they are equal.
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### impl<T> Filterable for T

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#### fn filterable( self, filter_name: &'static str ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T> Instrument for T

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#### fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided `Span`, returning an `Instrumented` wrapper. Read more
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#### fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more
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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> Pointable for T

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#### const ALIGN: usize = _

The alignment of pointer.
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#### type Init = T

The type for initializers.
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#### unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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#### unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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#### unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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#### unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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### impl<T> Same for T

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#### type Output = T

Should always be `Self`
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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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### impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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#### fn vzip(self) -> V

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### impl<T> WithSubscriber for T

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#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more
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#### fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more
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### impl<'a, T> Captures<'a> for T
where T: ?Sized,

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### impl<T> ErasedDestructor for T
where T: 'static,

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### impl<T> MaybeSendSync for T
where T: Send + Sync,

## Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain `repr(...)` attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes

Size for each variant:

- `Allow`: 0 bytes
- `Expect`: 20 bytes
- `Warn`: 0 bytes
- `ForceWarn`: 20 bytes
- `Deny`: 0 bytes
- `Forbid`: 0 bytes