rust/compiler/rustc_data_structures/src/fx.rs

use std::hash::BuildHasherDefault;

pub use rustc_hash::{FxHashMap, FxHashSet, FxHasher};

pub type StdEntry<'a, K, V> = std::collections::hash_map::Entry<'a, K, V>;

pub type FxIndexMap<K, V> = indexmap::IndexMap<K, V, BuildHasherDefault<FxHasher>>;
pub type FxIndexSet<V> = indexmap::IndexSet<V, BuildHasherDefault<FxHasher>>;
pub type IndexEntry<'a, K, V> = indexmap::map::Entry<'a, K, V>;

#[macro_export]
macro_rules! define_id_collections {
    ($map_name:ident, $set_name:ident, $entry_name:ident, $key:ty) => {
        pub type $map_name<T> = $crate::fx::FxHashMap<$key, T>;
        pub type $set_name = $crate::fx::FxHashSet<$key>;
        pub type $entry_name<'a, T> = $crate::fx::StdEntry<'a, $key, T>;
    };
}

#[macro_export]
macro_rules! define_stable_id_collections {
    ($map_name:ident, $set_name:ident, $entry_name:ident, $key:ty) => {
        pub type $map_name<T> = $crate::fx::FxIndexMap<$key, T>;
        pub type $set_name = $crate::fx::FxIndexSet<$key>;
        pub type $entry_name<'a, T> = $crate::fx::IndexEntry<'a, $key, T>;
    };
}