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

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

Fields

attr_id: AttrId
lint_index: Option<u16>

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

Stable

Fields

hir_id: HirId
attr_index: u16
lint_index: Option<u16>

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.

Implementations

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

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

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

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