pub enum DefIdForest<'a> {
    Empty,
    Single(DefId),
    Multiple(&'a [DefId]),
}
Expand description

Represents a forest of DefIds closed under the ancestor relation. That is, if a DefId representing a module is contained in the forest then all DefIds defined in that module or submodules are also implicitly contained in the forest.

This is used to represent a set of modules in which a type is visibly uninhabited.

We store the minimal set of DefIds required to represent the whole set. If A and B are DefIds in the DefIdForest, and A is a parent of B, then only A will be stored. When this is used with type_uninhabited_from, there will very rarely be more than one DefId stored.

Variants

Empty

Single(DefId)

Multiple(&'a [DefId])

This variant is very rare. Invariant: >1 elements

Implementations

Creates an empty forest.

Creates a forest consisting of a single tree representing the entire crate.

Creates a forest containing a DefId and all its descendants.

Tests whether the forest is empty.

Iterate over the set of roots.

Tests whether the forest contains a given DefId.

Calculate the intersection of a collection of forests.

Calculate the union of a collection of forests.

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

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

This method turns the parameters of a DepNodeConstructor into an opaque Fingerprint to be used in DepNode. Not all DepNodeParams support being turned into a Fingerprint (they don’t need to if the corresponding DepNode is anonymous). Read more

This method tries to recover the query key from the given DepNode, something which is needed when forcing DepNodes during red-green evaluation. The query system will only call this method if fingerprint_style() is not FingerprintStyle::Opaque. It is always valid to return None here, in which case incremental compilation will treat the query as having changed instead of forcing it. 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: 24 bytes

Size for each variant:

  • Empty: 0 bytes
  • Single: 8 bytes
  • Multiple: 20 bytes