Auto merge of #150353 - llogiq:rustc-hash-refactor, r=eholk

refactor rustc-hash integration

I found that rustc-hash is used in multiple compiler crates. Also some types use `FxBuildHasher` whereas others use `BuildHasherDefault<FxHasher>` (both do the same thing).

In order to simplify future hashing experiments, I changed every location to use `rustc_data_structures::fx::*` types instead, and also removed the `BuildHasherDefault` variant. This will simplify future experiments with hashing (for example trying out a hasher that doesn't implement `Default` for whatever reason).

Author: bors

compiler/rustc_data_structures/src/fx.rs

@@ -1,11 +1,9 @@
-use std::hash::BuildHasherDefault;
-
 pub use rustc_hash::{FxBuildHasher, 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 FxIndexMap<K, V> = indexmap::IndexMap<K, V, FxBuildHasher>;
+pub type FxIndexSet<V> = indexmap::IndexSet<V, FxBuildHasher>;
 pub type IndexEntry<'a, K, V> = indexmap::map::Entry<'a, K, V>;
 pub type IndexOccupiedEntry<'a, K, V> = indexmap::map::OccupiedEntry<'a, K, V>;
 

compiler/rustc_data_structures/src/unord.rs

@@ -8,10 +8,10 @@ use std::hash::Hash;
 use std::iter::{Product, Sum};
 use std::ops::Index;
 
-use rustc_hash::{FxBuildHasher, FxHashMap, FxHashSet};
 use rustc_macros::{Decodable_NoContext, Encodable_NoContext};
 
 use crate::fingerprint::Fingerprint;
+use crate::fx::{FxBuildHasher, FxHashMap, FxHashSet};
 use crate::stable_hasher::{HashStable, StableCompare, StableHasher, ToStableHashKey};
 
 /// `UnordItems` is the order-less version of `Iterator`. It only contains methods

compiler/rustc_type_ir/src/data_structures/mod.rs

@@ -1,11 +1,9 @@
-use std::hash::BuildHasherDefault;
-
 pub use ena::unify::{NoError, UnifyKey, UnifyValue};
-use rustc_hash::FxHasher;
+use rustc_hash::FxBuildHasher;
 pub use rustc_hash::{FxHashMap as HashMap, FxHashSet as HashSet};
 
-pub type IndexMap<K, V> = indexmap::IndexMap<K, V, BuildHasherDefault<FxHasher>>;
-pub type IndexSet<V> = indexmap::IndexSet<V, BuildHasherDefault<FxHasher>>;
+pub type IndexMap<K, V> = indexmap::IndexMap<K, V, FxBuildHasher>;
+pub type IndexSet<V> = indexmap::IndexSet<V, FxBuildHasher>;
 
 mod delayed_map;