# Type Definition cargo::core::resolver::types::FeaturesSet

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    pub type FeaturesSet = Rc<BTreeSet<InternedString>>;

Expand description

The preferred way to store the set of activated features for a package. This is sorted so that it impls Hash, and owns its contents, needed so it can be part of the key for caching in the `DepsCache`. It is also cloned often as part of `Context`, hence the `RC`. `im-rs::OrdSet` was slower of small sets like this, but this can change with improvements to std, im, or llvm. Using a consistent type for this allows us to use the highly optimized comparison operators like `is_subset` at the interfaces.

## 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: 8 bytes