1 files changed, 14 insertions, 0 deletions
diff --git a/compiler/rustc_data_structures/src/fx.rs b/compiler/rustc_data_structures/src/fx.rs
new file mode 100644
index 000000000..bbeb193db
--- /dev/null
+++ b/compiler/rustc_data_structures/src/fx.rs
@@ -0,0 +1,14 @@
+use std::hash::BuildHasherDefault;
+
+pub use rustc_hash::{FxHashMap, FxHashSet, FxHasher};
+
+pub type FxIndexMap<K, V> = indexmap::IndexMap<K, V, BuildHasherDefault<FxHasher>>;
+pub type FxIndexSet<V> = indexmap::IndexSet<V, BuildHasherDefault<FxHasher>>;
+
+#[macro_export]
+macro_rules! define_id_collections {
+    ($map_name:ident, $set_name:ident, $key:ty) => {
+        pub type $map_name<T> = $crate::fx::FxHashMap<$key, T>;
+        pub type $set_name = $crate::fx::FxHashSet<$key>;
+    };
+}