Use nohash_hasher, rm comment

Cargo.lock

@@ -917,7 +917,7 @@ version = "0.0.0"
 name = "line-index"
 version = "0.1.0"
 dependencies = [
- "non-hash",
+ "nohash-hasher",
  "text-size",
 ]
 
@@ -1064,8 +1064,10 @@ dependencies = [
 ]
 
 [[package]]
-name = "non-hash"
-version = "0.1.0"
+name = "nohash-hasher"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2bf50223579dc7cdcfb3bfcacf7069ff68243f8c363f62ffa99cf000a6b9c451"
 
 [[package]]
 name = "notify"
@@ -1706,7 +1708,7 @@ dependencies = [
  "backtrace",
  "libc",
  "miow",
- "non-hash",
+ "nohash-hasher",
  "winapi",
 ]
 

Cargo.toml

@@ -74,10 +74,12 @@ toolchain = { path = "./crates/toolchain", version = "0.0.0" }
 tt = { path = "./crates/tt", version = "0.0.0" }
 vfs-notify = { path = "./crates/vfs-notify", version = "0.0.0" }
 vfs = { path = "./crates/vfs", version = "0.0.0" }
+line-index = { version = "0.1.0", path = "./lib/line-index" }
 
 # non-local crates
 smallvec = { version = "1.10.0", features = ["const_new", "union", "const_generics"] }
 smol_str = "0.2.0"
+nohash-hasher = "0.2.0"
 # the following crates are pinned to prevent us from pulling in syn 2 until all our dependencies have moved
 serde = { version = "=1.0.156", features = ["derive"] }
 serde_json = "1.0.94"

crates/ide-db/Cargo.toml

@@ -37,8 +37,7 @@ text-edit.workspace = true
 # something from some `hir-xxx` subpackage, reexport the API via `hir`.
 hir.workspace = true
 
-# used to be a module, turned into its own library
-line-index = { version = "0.1.0", path = "../../lib/line-index" }
+line-index.workspace = true
 
 [dev-dependencies]
 expect-test = "1.4.0"

crates/stdx/Cargo.toml

@@ -15,7 +15,7 @@ doctest = false
 libc = "0.2.135"
 backtrace = { version = "0.3.65", optional = true }
 always-assert = { version = "0.1.2", features = ["log"] }
-non-hash = { version = "0.1.0", path = "../../lib/non-hash" }
+nohash-hasher.workspace = true
 # Think twice before adding anything here
 
 [target.'cfg(windows)'.dependencies]

crates/stdx/src/hash.rs

@@ -0,0 +1,5 @@
+//! Re-exports from [`nohash_hasher`].
+
+pub use nohash_hasher::IntMap as NoHashHashMap;
+pub use nohash_hasher::IntSet as NoHashHashSet;
+pub use nohash_hasher::IsEnabled;

crates/stdx/src/lib.rs

@@ -11,9 +11,9 @@ pub mod process;
 pub mod panic_context;
 pub mod non_empty_vec;
 pub mod rand;
+pub mod hash;
 
 pub use always_assert::{always, never};
-pub use non_hash as hash;
 
 #[inline(always)]
 pub fn is_ci() -> bool {

crates/vfs/src/lib.rs

@@ -62,7 +62,8 @@ pub use paths::{AbsPath, AbsPathBuf};
 #[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq, Hash)]
 pub struct FileId(pub u32);
 
-impl stdx::hash::NoHashHashable for FileId {}
+/// safe because `FileId` is a newtype of `u32`
+impl stdx::hash::IsEnabled for FileId {}
 
 /// Storage for all files read by rust-analyzer.
 ///

lib/line-index/Cargo.toml

@@ -3,9 +3,9 @@ name = "line-index"
 version = "0.1.0"
 description = "Maps flat `TextSize` offsets into `(line, column)` representation."
 license = "MIT OR Apache-2.0"
-repository = "https://github.com/rust-lang/rust-analyzer/tree/master/lib/non-hash"
+repository = "https://github.com/rust-lang/rust-analyzer/tree/master/lib/line-index"
 edition = "2021"
 
 [dependencies]
 text-size = "1"
-non-hash = { version = "0.1.0", path = "../non-hash" }
+nohash-hasher.workspace = true

lib/line-index/src/lib.rs

@@ -7,7 +7,7 @@ mod tests;
 
 use std::{iter, mem};
 
-use non_hash::NoHashHashMap;
+use nohash_hasher::IntMap as NoHashHashMap;
 use text_size::{TextRange, TextSize};
 
 /// Maps flat [`TextSize`] offsets into `(line, column)` representation.

lib/non-hash/Cargo.toml

@@ -1,7 +0,0 @@
-[package]
-name = "non-hash"
-version = "0.1.0"
-description = "A non-hashing `Hasher` implementation."
-license = "MIT OR Apache-2.0"
-repository = "https://github.com/rust-lang/rust-analyzer/tree/master/lib/non-hash"
-edition = "2021"

lib/non-hash/src/lib.rs

@@ -1,104 +0,0 @@
-//! A non-hashing [`Hasher`] implementation.
-
-#![deny(clippy::pedantic, missing_debug_implementations, missing_docs, rust_2018_idioms)]
-
-use std::{
-    hash::{BuildHasher, Hasher},
-    marker::PhantomData,
-};
-
-/// A [`std::collections::HashMap`] with [`NoHashHasherBuilder`].
-pub type NoHashHashMap<K, V> = std::collections::HashMap<K, V, NoHashHasherBuilder<K>>;
-
-/// A [`std::collections::HashSet`] with [`NoHashHasherBuilder`].
-pub type NoHashHashSet<K> = std::collections::HashSet<K, NoHashHasherBuilder<K>>;
-
-/// A hasher builder for [`NoHashHasher`].
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub struct NoHashHasherBuilder<T>(PhantomData<T>);
-
-impl<T> Default for NoHashHasherBuilder<T> {
-    fn default() -> Self {
-        Self(PhantomData)
-    }
-}
-
-/// Types for which an acceptable hash function is to return itself.
-///
-/// This trait is implemented by sufficiently-small integer types. It should only be implemented for
-/// foreign types that are newtypes of these types. If it is implemented on more complex types,
-/// hashing will panic.
-pub trait NoHashHashable {}
-
-impl NoHashHashable for u8 {}
-impl NoHashHashable for u16 {}
-impl NoHashHashable for u32 {}
-impl NoHashHashable for u64 {}
-impl NoHashHashable for usize {}
-
-impl NoHashHashable for i8 {}
-impl NoHashHashable for i16 {}
-impl NoHashHashable for i32 {}
-impl NoHashHashable for i64 {}
-impl NoHashHashable for isize {}
-
-/// A hasher for [`NoHashHashable`] types.
-#[derive(Debug)]
-pub struct NoHashHasher(u64);
-
-impl<T: NoHashHashable> BuildHasher for NoHashHasherBuilder<T> {
-    type Hasher = NoHashHasher;
-    fn build_hasher(&self) -> Self::Hasher {
-        NoHashHasher(0)
-    }
-}
-
-impl Hasher for NoHashHasher {
-    fn finish(&self) -> u64 {
-        self.0
-    }
-
-    fn write(&mut self, _: &[u8]) {
-        unimplemented!("NoHashHasher should only be used for hashing sufficiently-small integer types and their newtypes")
-    }
-
-    fn write_u8(&mut self, i: u8) {
-        self.0 = i as u64;
-    }
-
-    fn write_u16(&mut self, i: u16) {
-        self.0 = i as u64;
-    }
-
-    fn write_u32(&mut self, i: u32) {
-        self.0 = i as u64;
-    }
-
-    fn write_u64(&mut self, i: u64) {
-        self.0 = i;
-    }
-
-    fn write_usize(&mut self, i: usize) {
-        self.0 = i as u64;
-    }
-
-    fn write_i8(&mut self, i: i8) {
-        self.0 = i as u64;
-    }
-
-    fn write_i16(&mut self, i: i16) {
-        self.0 = i as u64;
-    }
-
-    fn write_i32(&mut self, i: i32) {
-        self.0 = i as u64;
-    }
-
-    fn write_i64(&mut self, i: i64) {
-        self.0 = i as u64;
-    }
-
-    fn write_isize(&mut self, i: isize) {
-        self.0 = i as u64;
-    }
-}