Auto merge of #13116 - Veykril:nohash, r=Veykril

Make use of NoHash hashing for FileId and CrateId

Both of these are mere integers so there is nothing to hash here.

Ideally we would use this for `la_arena::Idx` too, but that doesn't work due to the orphan rule, and `la_arena` is unfortunately a public library so we can't really do much here... Unless we remove the trait restriction but I'd like not to

Cargo.lock

@@ -704,6 +704,7 @@ dependencies = [
  "ide-db",
  "itertools",
  "parser",
+ "stdx",
  "syntax",
  "test-utils",
  "text-edit",
@@ -1921,6 +1922,7 @@ dependencies = [
  "indexmap",
  "paths",
  "rustc-hash",
+ "stdx",
 ]
 
 [[package]]

crates/base-db/src/input.rs

@@ -9,10 +9,11 @@
 use std::{fmt, ops, panic::RefUnwindSafe, str::FromStr, sync::Arc};
 
 use cfg::CfgOptions;
-use rustc_hash::{FxHashMap, FxHashSet};
+use rustc_hash::FxHashMap;
+use stdx::hash::{NoHashHashMap, NoHashHashSet};
 use syntax::SmolStr;
 use tt::Subtree;
-use vfs::{file_set::FileSet, FileId, VfsPath};
+use vfs::{file_set::FileSet, AnchoredPath, FileId, VfsPath};
 
 /// Files are grouped into source roots. A source root is a directory on the
 /// file systems which is watched for changes. Typically it corresponds to a
@@ -31,22 +32,30 @@ pub struct SourceRoot {
     /// Libraries are considered mostly immutable, this assumption is used to
     /// optimize salsa's query structure
     pub is_library: bool,
-    pub(crate) file_set: FileSet,
+    file_set: FileSet,
 }
 
 impl SourceRoot {
     pub fn new_local(file_set: FileSet) -> SourceRoot {
         SourceRoot { is_library: false, file_set }
     }
+
     pub fn new_library(file_set: FileSet) -> SourceRoot {
         SourceRoot { is_library: true, file_set }
     }
+
     pub fn path_for_file(&self, file: &FileId) -> Option<&VfsPath> {
         self.file_set.path_for_file(file)
     }
+
     pub fn file_for_path(&self, path: &VfsPath) -> Option<&FileId> {
         self.file_set.file_for_path(path)
     }
+
+    pub fn resolve_path(&self, path: AnchoredPath<'_>) -> Option<FileId> {
+        self.file_set.resolve_path(path)
+    }
+
     pub fn iter(&self) -> impl Iterator<Item = FileId> + '_ {
         self.file_set.iter()
     }
@@ -72,12 +81,19 @@ impl SourceRoot {
 /// <https://github.com/rust-lang/rust-analyzer/blob/master/docs/dev/architecture.md#serialization>
 #[derive(Debug, Clone, Default /* Serialize, Deserialize */)]
 pub struct CrateGraph {
-    arena: FxHashMap<CrateId, CrateData>,
+    arena: NoHashHashMap<CrateId, CrateData>,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub struct CrateId(pub u32);
 
+impl stdx::hash::NoHashHashable for CrateId {}
+impl std::hash::Hash for CrateId {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.0.hash(state);
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct CrateName(SmolStr);
 
@@ -342,7 +358,7 @@ impl CrateGraph {
         // Check if adding a dep from `from` to `to` creates a cycle. To figure
         // that out, look for a  path in the *opposite* direction, from `to` to
         // `from`.
-        if let Some(path) = self.find_path(&mut FxHashSet::default(), dep.crate_id, from) {
+        if let Some(path) = self.find_path(&mut NoHashHashSet::default(), dep.crate_id, from) {
             let path = path.into_iter().map(|it| (it, self[it].display_name.clone())).collect();
             let err = CyclicDependenciesError { path };
             assert!(err.from().0 == from && err.to().0 == dep.crate_id);
@@ -365,7 +381,7 @@ impl CrateGraph {
     /// including the crate itself.
     pub fn transitive_deps(&self, of: CrateId) -> impl Iterator<Item = CrateId> {
         let mut worklist = vec![of];
-        let mut deps = FxHashSet::default();
+        let mut deps = NoHashHashSet::default();
 
         while let Some(krate) = worklist.pop() {
             if !deps.insert(krate) {
@@ -382,10 +398,10 @@ impl CrateGraph {
     /// including the crate itself.
     pub fn transitive_rev_deps(&self, of: CrateId) -> impl Iterator<Item = CrateId> {
         let mut worklist = vec![of];
-        let mut rev_deps = FxHashSet::default();
+        let mut rev_deps = NoHashHashSet::default();
         rev_deps.insert(of);
 
-        let mut inverted_graph = FxHashMap::<_, Vec<_>>::default();
+        let mut inverted_graph = NoHashHashMap::<_, Vec<_>>::default();
         self.arena.iter().for_each(|(&krate, data)| {
             data.dependencies
                 .iter()
@@ -409,7 +425,7 @@ impl CrateGraph {
     /// come before the crate itself).
     pub fn crates_in_topological_order(&self) -> Vec<CrateId> {
         let mut res = Vec::new();
-        let mut visited = FxHashSet::default();
+        let mut visited = NoHashHashSet::default();
 
         for krate in self.arena.keys().copied() {
             go(self, &mut visited, &mut res, krate);
@@ -419,7 +435,7 @@ impl CrateGraph {
 
         fn go(
             graph: &CrateGraph,
-            visited: &mut FxHashSet<CrateId>,
+            visited: &mut NoHashHashSet<CrateId>,
             res: &mut Vec<CrateId>,
             source: CrateId,
         ) {
@@ -459,7 +475,7 @@ impl CrateGraph {
 
     fn find_path(
         &self,
-        visited: &mut FxHashSet<CrateId>,
+        visited: &mut NoHashHashSet<CrateId>,
         from: CrateId,
         to: CrateId,
     ) -> Option<Vec<CrateId>> {

crates/base-db/src/lib.rs

@@ -8,7 +8,7 @@ pub mod fixture;
 
 use std::{panic, sync::Arc};
 
-use rustc_hash::FxHashSet;
+use stdx::hash::NoHashHashSet;
 use syntax::{ast, Parse, SourceFile, TextRange, TextSize};
 
 pub use crate::{
@@ -58,7 +58,7 @@ pub trait FileLoader {
     /// Text of the file.
     fn file_text(&self, file_id: FileId) -> Arc<String>;
     fn resolve_path(&self, path: AnchoredPath<'_>) -> Option<FileId>;
-    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>>;
+    fn relevant_crates(&self, file_id: FileId) -> Arc<NoHashHashSet<CrateId>>;
 }
 
 /// Database which stores all significant input facts: source code and project
@@ -94,10 +94,10 @@ pub trait SourceDatabaseExt: SourceDatabase {
     #[salsa::input]
     fn source_root(&self, id: SourceRootId) -> Arc<SourceRoot>;
 
-    fn source_root_crates(&self, id: SourceRootId) -> Arc<FxHashSet<CrateId>>;
+    fn source_root_crates(&self, id: SourceRootId) -> Arc<NoHashHashSet<CrateId>>;
 }
 
-fn source_root_crates(db: &dyn SourceDatabaseExt, id: SourceRootId) -> Arc<FxHashSet<CrateId>> {
+fn source_root_crates(db: &dyn SourceDatabaseExt, id: SourceRootId) -> Arc<NoHashHashSet<CrateId>> {
     let graph = db.crate_graph();
     let res = graph
         .iter()
@@ -120,10 +120,10 @@ impl<T: SourceDatabaseExt> FileLoader for FileLoaderDelegate<&'_ T> {
         // FIXME: this *somehow* should be platform agnostic...
         let source_root = self.0.file_source_root(path.anchor);
         let source_root = self.0.source_root(source_root);
-        source_root.file_set.resolve_path(path)
+        source_root.resolve_path(path)
     }
 
-    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
+    fn relevant_crates(&self, file_id: FileId) -> Arc<NoHashHashSet<CrateId>> {
         let _p = profile::span("relevant_crates");
         let source_root = self.0.file_source_root(file_id);
         self.0.source_root_crates(source_root)

crates/hir-def/src/test_db.rs

@@ -10,7 +10,7 @@ use base_db::{
     SourceDatabase, Upcast,
 };
 use hir_expand::{db::AstDatabase, InFile};
-use rustc_hash::FxHashSet;
+use stdx::hash::NoHashHashSet;
 use syntax::{algo, ast, AstNode};
 
 use crate::{
@@ -76,7 +76,7 @@ impl FileLoader for TestDB {
     fn resolve_path(&self, path: AnchoredPath<'_>) -> Option<FileId> {
         FileLoaderDelegate(self).resolve_path(path)
     }
-    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
+    fn relevant_crates(&self, file_id: FileId) -> Arc<NoHashHashSet<CrateId>> {
         FileLoaderDelegate(self).relevant_crates(file_id)
     }
 }

crates/hir-ty/src/test_db.rs

@@ -10,7 +10,7 @@ use base_db::{
 };
 use hir_def::{db::DefDatabase, ModuleId};
 use hir_expand::db::AstDatabase;
-use rustc_hash::{FxHashMap, FxHashSet};
+use stdx::hash::{NoHashHashMap, NoHashHashSet};
 use syntax::TextRange;
 use test_utils::extract_annotations;
 
@@ -80,7 +80,7 @@ impl FileLoader for TestDB {
     fn resolve_path(&self, path: AnchoredPath<'_>) -> Option<FileId> {
         FileLoaderDelegate(self).resolve_path(path)
     }
-    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
+    fn relevant_crates(&self, file_id: FileId) -> Arc<NoHashHashSet<CrateId>> {
         FileLoaderDelegate(self).relevant_crates(file_id)
     }
 }
@@ -102,7 +102,7 @@ impl TestDB {
         self.module_for_file_opt(file_id).unwrap()
     }
 
-    pub(crate) fn extract_annotations(&self) -> FxHashMap<FileId, Vec<(TextRange, String)>> {
+    pub(crate) fn extract_annotations(&self) -> NoHashHashMap<FileId, Vec<(TextRange, String)>> {
         let mut files = Vec::new();
         let crate_graph = self.crate_graph();
         for krate in crate_graph.iter() {

crates/ide-db/src/lib.rs

@@ -52,6 +52,7 @@ use hir::{
     db::{AstDatabase, DefDatabase, HirDatabase},
     symbols::FileSymbolKind,
 };
+use stdx::hash::NoHashHashSet;
 
 use crate::{line_index::LineIndex, symbol_index::SymbolsDatabase};
 pub use rustc_hash::{FxHashMap, FxHashSet, FxHasher};
@@ -118,7 +119,7 @@ impl FileLoader for RootDatabase {
     fn resolve_path(&self, path: AnchoredPath<'_>) -> Option<FileId> {
         FileLoaderDelegate(self).resolve_path(path)
     }
-    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
+    fn relevant_crates(&self, file_id: FileId) -> Arc<NoHashHashSet<CrateId>> {
         FileLoaderDelegate(self).relevant_crates(file_id)
     }
 }

crates/ide-db/src/line_index.rs

@@ -2,7 +2,7 @@
 //! representation.
 use std::{iter, mem};
 
-use rustc_hash::FxHashMap;
+use stdx::hash::NoHashHashMap;
 use syntax::{TextRange, TextSize};
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -10,7 +10,7 @@ pub struct LineIndex {
     /// Offset the the beginning of each line, zero-based
     pub(crate) newlines: Vec<TextSize>,
     /// List of non-ASCII characters on each line
-    pub(crate) utf16_lines: FxHashMap<u32, Vec<Utf16Char>>,
+    pub(crate) utf16_lines: NoHashHashMap<u32, Vec<Utf16Char>>,
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
@@ -55,7 +55,7 @@ impl Utf16Char {
 
 impl LineIndex {
     pub fn new(text: &str) -> LineIndex {
-        let mut utf16_lines = FxHashMap::default();
+        let mut utf16_lines = NoHashHashMap::default();
         let mut utf16_chars = Vec::new();
 
         let mut newlines = vec![0.into()];

crates/ide-db/src/search.rs

@@ -9,7 +9,7 @@ use std::{mem, sync::Arc};
 use base_db::{FileId, FileRange, SourceDatabase, SourceDatabaseExt};
 use hir::{DefWithBody, HasAttrs, HasSource, InFile, ModuleSource, Semantics, Visibility};
 use once_cell::unsync::Lazy;
-use rustc_hash::FxHashMap;
+use stdx::hash::NoHashHashMap;
 use syntax::{ast, match_ast, AstNode, TextRange, TextSize};
 
 use crate::{
@@ -20,7 +20,7 @@ use crate::{
 
 #[derive(Debug, Default, Clone)]
 pub struct UsageSearchResult {
-    pub references: FxHashMap<FileId, Vec<FileReference>>,
+    pub references: NoHashHashMap<FileId, Vec<FileReference>>,
 }
 
 impl UsageSearchResult {
@@ -45,7 +45,7 @@ impl UsageSearchResult {
 
 impl IntoIterator for UsageSearchResult {
     type Item = (FileId, Vec<FileReference>);
-    type IntoIter = <FxHashMap<FileId, Vec<FileReference>> as IntoIterator>::IntoIter;
+    type IntoIter = <NoHashHashMap<FileId, Vec<FileReference>> as IntoIterator>::IntoIter;
 
     fn into_iter(self) -> Self::IntoIter {
         self.references.into_iter()
@@ -78,17 +78,17 @@ pub enum ReferenceCategory {
 /// e.g. for things like local variables.
 #[derive(Clone, Debug)]
 pub struct SearchScope {
-    entries: FxHashMap<FileId, Option<TextRange>>,
+    entries: NoHashHashMap<FileId, Option<TextRange>>,
 }
 
 impl SearchScope {
-    fn new(entries: FxHashMap<FileId, Option<TextRange>>) -> SearchScope {
+    fn new(entries: NoHashHashMap<FileId, Option<TextRange>>) -> SearchScope {
         SearchScope { entries }
     }
 
     /// Build a search scope spanning the entire crate graph of files.
     fn crate_graph(db: &RootDatabase) -> SearchScope {
-        let mut entries = FxHashMap::default();
+        let mut entries = NoHashHashMap::default();
 
         let graph = db.crate_graph();
         for krate in graph.iter() {
@@ -102,7 +102,7 @@ impl SearchScope {
 
     /// Build a search scope spanning all the reverse dependencies of the given crate.
     fn reverse_dependencies(db: &RootDatabase, of: hir::Crate) -> SearchScope {
-        let mut entries = FxHashMap::default();
+        let mut entries = NoHashHashMap::default();
         for rev_dep in of.transitive_reverse_dependencies(db) {
             let root_file = rev_dep.root_file(db);
             let source_root_id = db.file_source_root(root_file);
@@ -117,14 +117,12 @@ impl SearchScope {
         let root_file = of.root_file(db);
         let source_root_id = db.file_source_root(root_file);
         let source_root = db.source_root(source_root_id);
-        SearchScope {
-            entries: source_root.iter().map(|id| (id, None)).collect::<FxHashMap<_, _>>(),
-        }
+        SearchScope { entries: source_root.iter().map(|id| (id, None)).collect() }
     }
 
     /// Build a search scope spanning the given module and all its submodules.
     fn module_and_children(db: &RootDatabase, module: hir::Module) -> SearchScope {
-        let mut entries = FxHashMap::default();
+        let mut entries = NoHashHashMap::default();
 
         let (file_id, range) = {
             let InFile { file_id, value } = module.definition_source(db);
@@ -157,7 +155,7 @@ impl SearchScope {
 
     /// Build an empty search scope.
     pub fn empty() -> SearchScope {
-        SearchScope::new(FxHashMap::default())
+        SearchScope::new(NoHashHashMap::default())
     }
 
     /// Build a empty search scope spanning the given file.

crates/ide-db/src/source_change.rs

@@ -6,8 +6,7 @@
 use std::{collections::hash_map::Entry, iter, mem};
 
 use base_db::{AnchoredPathBuf, FileId};
-use rustc_hash::FxHashMap;
-use stdx::never;
+use stdx::{hash::NoHashHashMap, never};
 use syntax::{algo, AstNode, SyntaxNode, SyntaxNodePtr, TextRange, TextSize};
 use text_edit::{TextEdit, TextEditBuilder};
 
@@ -15,7 +14,7 @@ use crate::SnippetCap;
 
 #[derive(Default, Debug, Clone)]
 pub struct SourceChange {
-    pub source_file_edits: FxHashMap<FileId, TextEdit>,
+    pub source_file_edits: NoHashHashMap<FileId, TextEdit>,
     pub file_system_edits: Vec<FileSystemEdit>,
     pub is_snippet: bool,
 }
@@ -24,7 +23,7 @@ impl SourceChange {
     /// Creates a new SourceChange with the given label
     /// from the edits.
     pub fn from_edits(
-        source_file_edits: FxHashMap<FileId, TextEdit>,
+        source_file_edits: NoHashHashMap<FileId, TextEdit>,
         file_system_edits: Vec<FileSystemEdit>,
     ) -> Self {
         SourceChange { source_file_edits, file_system_edits, is_snippet: false }
@@ -78,8 +77,8 @@ impl Extend<FileSystemEdit> for SourceChange {
     }
 }
 
-impl From<FxHashMap<FileId, TextEdit>> for SourceChange {
-    fn from(source_file_edits: FxHashMap<FileId, TextEdit>) -> SourceChange {
+impl From<NoHashHashMap<FileId, TextEdit>> for SourceChange {
+    fn from(source_file_edits: NoHashHashMap<FileId, TextEdit>) -> SourceChange {
         SourceChange { source_file_edits, file_system_edits: Vec::new(), is_snippet: false }
     }
 }

crates/ide-ssr/Cargo.toml

@@ -20,6 +20,7 @@ parser = { path = "../parser", version = "0.0.0" }
 syntax = { path = "../syntax", version = "0.0.0" }
 ide-db = { path = "../ide-db", version = "0.0.0" }
 hir = { path = "../hir", version = "0.0.0" }
+stdx = { path = "../stdx", version = "0.0.0" }
 
 [dev-dependencies]
 test-utils = { path = "../test-utils" }

crates/ide-ssr/src/lib.rs

@@ -86,11 +86,9 @@ pub use crate::{errors::SsrError, from_comment::ssr_from_comment, matching::Matc
 
 use crate::{errors::bail, matching::MatchFailureReason};
 use hir::Semantics;
-use ide_db::{
-    base_db::{FileId, FilePosition, FileRange},
-    FxHashMap,
-};
+use ide_db::base_db::{FileId, FilePosition, FileRange};
 use resolving::ResolvedRule;
+use stdx::hash::NoHashHashMap;
 use syntax::{ast, AstNode, SyntaxNode, TextRange};
 use text_edit::TextEdit;
 
@@ -170,9 +168,9 @@ impl<'db> MatchFinder<'db> {
     }
 
     /// Finds matches for all added rules and returns edits for all found matches.
-    pub fn edits(&self) -> FxHashMap<FileId, TextEdit> {
+    pub fn edits(&self) -> NoHashHashMap<FileId, TextEdit> {
         use ide_db::base_db::SourceDatabaseExt;
-        let mut matches_by_file = FxHashMap::default();
+        let mut matches_by_file = NoHashHashMap::default();
         for m in self.matches().matches {
             matches_by_file
                 .entry(m.range.file_id)

crates/ide/src/prime_caches.rs

@@ -12,8 +12,9 @@ use ide_db::{
         salsa::{Database, ParallelDatabase, Snapshot},
         Cancelled, CrateGraph, CrateId, SourceDatabase, SourceDatabaseExt,
     },
-    FxHashSet, FxIndexMap,
+    FxIndexMap,
 };
+use stdx::hash::NoHashHashSet;
 
 use crate::RootDatabase;
 
@@ -141,7 +142,7 @@ pub(crate) fn parallel_prime_caches(
     }
 }
 
-fn compute_crates_to_prime(db: &RootDatabase, graph: &CrateGraph) -> FxHashSet<CrateId> {
+fn compute_crates_to_prime(db: &RootDatabase, graph: &CrateGraph) -> NoHashHashSet<CrateId> {
     // We're only interested in the workspace crates and the `ImportMap`s of their direct
     // dependencies, though in practice the latter also compute the `DefMap`s.
     // We don't prime transitive dependencies because they're generally not visible in

crates/ide/src/references.rs

@@ -14,8 +14,9 @@ use ide_db::{
     base_db::FileId,
     defs::{Definition, NameClass, NameRefClass},
     search::{ReferenceCategory, SearchScope, UsageSearchResult},
-    FxHashMap, RootDatabase,
+    RootDatabase,
 };
+use stdx::hash::NoHashHashMap;
 use syntax::{
     algo::find_node_at_offset,
     ast::{self, HasName},
@@ -29,7 +30,7 @@ use crate::{FilePosition, NavigationTarget, TryToNav};
 #[derive(Debug, Clone)]
 pub struct ReferenceSearchResult {
     pub declaration: Option<Declaration>,
-    pub references: FxHashMap<FileId, Vec<(TextRange, Option<ReferenceCategory>)>>,
+    pub references: NoHashHashMap<FileId, Vec<(TextRange, Option<ReferenceCategory>)>>,
 }
 
 #[derive(Debug, Clone)]

crates/ide/src/view_crate_graph.rs

@@ -3,8 +3,9 @@ use std::sync::Arc;
 use dot::{Id, LabelText};
 use ide_db::{
     base_db::{CrateGraph, CrateId, Dependency, SourceDatabase, SourceDatabaseExt},
-    FxHashSet, RootDatabase,
+    RootDatabase,
 };
+use stdx::hash::NoHashHashSet;
 
 // Feature: View Crate Graph
 //
@@ -41,7 +42,7 @@ pub(crate) fn view_crate_graph(db: &RootDatabase, full: bool) -> Result<String,
 
 struct DotCrateGraph {
     graph: Arc<CrateGraph>,
-    crates_to_render: FxHashSet<CrateId>,
+    crates_to_render: NoHashHashSet<CrateId>,
 }
 
 type Edge<'a> = (CrateId, &'a Dependency);

crates/project-model/src/workspace.rs

@@ -13,7 +13,7 @@ use cfg::{CfgDiff, CfgOptions};
 use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::{FxHashMap, FxHashSet};
 use semver::Version;
-use stdx::always;
+use stdx::{always, hash::NoHashHashMap};
 
 use crate::{
     build_scripts::BuildScriptOutput,
@@ -471,7 +471,7 @@ fn project_json_to_crate_graph(
         .map(|sysroot| sysroot_to_crate_graph(&mut crate_graph, sysroot, rustc_cfg.clone(), load));
 
     let mut cfg_cache: FxHashMap<&str, Vec<CfgFlag>> = FxHashMap::default();
-    let crates: FxHashMap<CrateId, CrateId> = project
+    let crates: NoHashHashMap<CrateId, CrateId> = project
         .crates()
         .filter_map(|(crate_id, krate)| {
             let file_path = &krate.root_module;

crates/rust-analyzer/src/diagnostics.rs

@@ -4,11 +4,12 @@ pub(crate) mod to_proto;
 use std::{mem, sync::Arc};
 
 use ide::FileId;
-use rustc_hash::{FxHashMap, FxHashSet};
+use ide_db::FxHashMap;
+use stdx::hash::{NoHashHashMap, NoHashHashSet};
 
 use crate::lsp_ext;
 
-pub(crate) type CheckFixes = Arc<FxHashMap<usize, FxHashMap<FileId, Vec<Fix>>>>;
+pub(crate) type CheckFixes = Arc<NoHashHashMap<usize, NoHashHashMap<FileId, Vec<Fix>>>>;
 
 #[derive(Debug, Default, Clone)]
 pub struct DiagnosticsMapConfig {
@@ -19,12 +20,12 @@ pub struct DiagnosticsMapConfig {
 
 #[derive(Debug, Default, Clone)]
 pub(crate) struct DiagnosticCollection {
-    // FIXME: should be FxHashMap<FileId, Vec<ra_id::Diagnostic>>
-    pub(crate) native: FxHashMap<FileId, Vec<lsp_types::Diagnostic>>,
+    // FIXME: should be NoHashHashMap<FileId, Vec<ra_id::Diagnostic>>
+    pub(crate) native: NoHashHashMap<FileId, Vec<lsp_types::Diagnostic>>,
     // FIXME: should be Vec<flycheck::Diagnostic>
-    pub(crate) check: FxHashMap<usize, FxHashMap<FileId, Vec<lsp_types::Diagnostic>>>,
+    pub(crate) check: NoHashHashMap<usize, NoHashHashMap<FileId, Vec<lsp_types::Diagnostic>>>,
     pub(crate) check_fixes: CheckFixes,
-    changes: FxHashSet<FileId>,
+    changes: NoHashHashSet<FileId>,
 }
 
 #[derive(Debug, Clone)]
@@ -105,7 +106,7 @@ impl DiagnosticCollection {
         native.chain(check)
     }
 
-    pub(crate) fn take_changes(&mut self) -> Option<FxHashSet<FileId>> {
+    pub(crate) fn take_changes(&mut self) -> Option<NoHashHashSet<FileId>> {
         if self.changes.is_empty() {
             return None;
         }

crates/rust-analyzer/src/global_state.rs

@@ -14,6 +14,7 @@ use parking_lot::{Mutex, RwLock};
 use proc_macro_api::ProcMacroServer;
 use project_model::{CargoWorkspace, ProjectWorkspace, Target, WorkspaceBuildScripts};
 use rustc_hash::FxHashMap;
+use stdx::hash::NoHashHashMap;
 use vfs::AnchoredPathBuf;
 
 use crate::{
@@ -67,7 +68,7 @@ pub(crate) struct GlobalState {
     pub(crate) flycheck_sender: Sender<flycheck::Message>,
     pub(crate) flycheck_receiver: Receiver<flycheck::Message>,
 
-    pub(crate) vfs: Arc<RwLock<(vfs::Vfs, FxHashMap<FileId, LineEndings>)>>,
+    pub(crate) vfs: Arc<RwLock<(vfs::Vfs, NoHashHashMap<FileId, LineEndings>)>>,
     pub(crate) vfs_config_version: u32,
     pub(crate) vfs_progress_config_version: u32,
     pub(crate) vfs_progress_n_total: usize,
@@ -113,7 +114,7 @@ pub(crate) struct GlobalStateSnapshot {
     pub(crate) check_fixes: CheckFixes,
     mem_docs: MemDocs,
     pub(crate) semantic_tokens_cache: Arc<Mutex<FxHashMap<Url, SemanticTokens>>>,
-    vfs: Arc<RwLock<(vfs::Vfs, FxHashMap<FileId, LineEndings>)>>,
+    vfs: Arc<RwLock<(vfs::Vfs, NoHashHashMap<FileId, LineEndings>)>>,
     pub(crate) workspaces: Arc<Vec<ProjectWorkspace>>,
 }
 
@@ -157,7 +158,7 @@ impl GlobalState {
             flycheck_sender,
             flycheck_receiver,
 
-            vfs: Arc::new(RwLock::new((vfs::Vfs::default(), FxHashMap::default()))),
+            vfs: Arc::new(RwLock::new((vfs::Vfs::default(), NoHashHashMap::default()))),
             vfs_config_version: 0,
             vfs_progress_config_version: 0,
             vfs_progress_n_total: 0,

crates/stdx/src/hash.rs

@@ -0,0 +1,80 @@
+//! A none hashing [`Hasher`] implementation.
+use std::{
+    hash::{BuildHasher, Hasher},
+    marker::PhantomData,
+};
+
+pub type NoHashHashMap<K, V> = std::collections::HashMap<K, V, NoHashHasherBuilder<K>>;
+pub type NoHashHashSet<K> = std::collections::HashSet<K, NoHashHasherBuilder<K>>;
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub struct NoHashHasherBuilder<T>(PhantomData<T>);
+
+impl<T> Default for NoHashHasherBuilder<T> {
+    fn default() -> Self {
+        Self(Default::default())
+    }
+}
+
+pub trait NoHashHashable {}
+impl NoHashHashable for usize {}
+impl NoHashHashable for u32 {}
+
+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 primitive integers")
+    }
+
+    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 as u64;
+    }
+
+    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;
+    }
+}

crates/stdx/src/lib.rs

@@ -7,6 +7,7 @@ use std::{cmp::Ordering, ops, time::Instant};
 use std::{io as sio, iter};
 
 mod macros;
+pub mod hash;
 pub mod process;
 pub mod panic_context;
 pub mod non_empty_vec;

crates/vfs/Cargo.toml

@@ -12,6 +12,7 @@ doctest = false
 [dependencies]
 rustc-hash = "1.1.0"
 fst = "0.4.7"
+indexmap = "1.9.1"
 
 paths = { path = "../paths", version = "0.0.0" }
-indexmap = "1.9.1"
+stdx = { path = "../stdx", version = "0.0.0" }

crates/vfs/src/file_set.rs

@@ -6,6 +6,7 @@ use std::fmt;
 
 use fst::{IntoStreamer, Streamer};
 use rustc_hash::FxHashMap;
+use stdx::hash::NoHashHashMap;
 
 use crate::{AnchoredPath, FileId, Vfs, VfsPath};
 
@@ -13,7 +14,7 @@ use crate::{AnchoredPath, FileId, Vfs, VfsPath};
 #[derive(Default, Clone, Eq, PartialEq)]
 pub struct FileSet {
     files: FxHashMap<VfsPath, FileId>,
-    paths: FxHashMap<FileId, VfsPath>,
+    paths: NoHashHashMap<FileId, VfsPath>,
 }
 
 impl FileSet {

crates/vfs/src/lib.rs

@@ -59,9 +59,16 @@ pub use paths::{AbsPath, AbsPathBuf};
 /// Handle to a file in [`Vfs`]
 ///
 /// Most functions in rust-analyzer use this when they need to refer to a file.
-#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq, Hash)]
+#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq)]
 pub struct FileId(pub u32);
 
+impl stdx::hash::NoHashHashable for FileId {}
+impl std::hash::Hash for FileId {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.0.hash(state);
+    }
+}
+
 /// Storage for all files read by rust-analyzer.
 ///
 /// For more information see the [crate-level](crate) documentation.