Enum LintExpectationId

pub enum LintExpectationId {
    Unstable {
        attr_id: AttrId,
        lint_index: Option<u16>,
    },
    Stable {
        hir_id: HirId,
        attr_index: u16,
        lint_index: Option<u16>,
    },
}

Each lint expectation has a LintExpectationId assigned by the LintLevelsBuilder. Expected diagnostics get the lint level Expect which stores the LintExpectationId to match it with the actual expectation later on.

The LintExpectationId has to be stable between compilations, as diagnostic instances might be loaded from cache. Lint messages can be emitted during an EarlyLintPass operating on the AST and during a LateLintPass traversing the HIR tree. The AST doesn’t have enough information to create a stable id. The LintExpectationId will instead store the AttrId defining the expectation. These LintExpectationId will be updated to use the stable HirId once the AST has been lowered. The transformation is done by the LintLevelsBuilder

Each lint inside the expect attribute is tracked individually, the lint_index identifies the lint inside the attribute and ensures that the IDs are unique.

The index values have a type of u16 to reduce the size of the LintExpectationId. It’s reasonable to assume that no user will define 2^16 attributes on one node or have that amount of lints listed. u16 values should therefore suffice.

Variants

Unstable

Used for lints emitted during the EarlyLintPass. This id is not hash stable and should not be cached.

Fields

attr_id: AttrId

lint_index: Option<u16>

Stable

The HirId that the lint expectation is attached to. This id is stable and can be cached. The additional index ensures that nodes with several expectations can correctly match diagnostics to the individual expectation.

Fields

hir_id: HirId

attr_index: u16

lint_index: Option<u16>

Implementations

impl LintExpectationId

pub fn is_stable(&self) -> bool

pub fn get_lint_index(&self) -> Option<u16>

pub fn set_lint_index(&mut self, new_lint_index: Option<u16>)

Trait Implementations

impl Clone for LintExpectationId

fn clone(&self) -> LintExpectationId

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LintExpectationId

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

Formats the value using the given formatter.

impl<__D: SpanDecoder> Decodable<__D> for LintExpectationId

fn decode(__decoder: &mut __D) -> Self

impl<__E: SpanEncoder> Encodable<__E> for LintExpectationId

fn encode(&self, __encoder: &mut __E)

impl Hash for LintExpectationId

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

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<HCX: HashStableContext> HashStable<HCX> for LintExpectationId

fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher)

impl PartialEq for LintExpectationId

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

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<HCX: HashStableContext> ToStableHashKey<HCX> for LintExpectationId

type KeyType = (DefPathHash, ItemLocalId, u16, u16)

fn to_stable_hash_key(&self, hcx: &HCX) -> Self::KeyType

impl Copy for LintExpectationId

impl Eq for LintExpectationId

impl StructuralPartialEq for LintExpectationId

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: 16 bytes

Size for each variant:

• Unstable: 10 bytes
• Stable: 14 bytes