diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index ff9909c720e547906ae7107eec60f6272533a164..24968e00cc8e5051a8e466d5296bac5bbcd5a4ea 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -34,7 +34,7 @@
 use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_ssa::{CodegenResults, CompiledModule};
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::{DiagnosticMessage, ErrorGuaranteed, FatalError, Handler, SubdiagnosticMessage};
 use rustc_fluent_macro::fluent_messages;
 use rustc_metadata::EncodedMetadata;
@@ -356,7 +356,7 @@ fn join_codegen(
         ongoing_codegen: Box<dyn Any>,
         sess: &Session,
         outputs: &OutputFilenames,
-    ) -> Result<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>), ErrorGuaranteed> {
+    ) -> Result<(CodegenResults, FxIndexMap<WorkProductId, WorkProduct>), ErrorGuaranteed> {
         let (codegen_results, work_products) = ongoing_codegen
             .downcast::<rustc_codegen_ssa::back::write::OngoingCodegen<LlvmCodegenBackend>>()
             .expect("Expected LlvmCodegenBackend's OngoingCodegen, found Box<Any>")
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index 10e9e5588f6cc6569096a69002c71f4d82d8c205..701d0d73ad38c60f2288b05f3a5ccec4710a2c04 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -9,7 +9,7 @@
 };
 use jobserver::{Acquired, Client};
 use rustc_ast::attr;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::profiling::TimingGuard;
@@ -498,8 +498,8 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
 fn copy_all_cgu_workproducts_to_incr_comp_cache_dir(
     sess: &Session,
     compiled_modules: &CompiledModules,
-) -> FxHashMap<WorkProductId, WorkProduct> {
-    let mut work_products = FxHashMap::default();
+) -> FxIndexMap<WorkProductId, WorkProduct> {
+    let mut work_products = FxIndexMap::default();
 
     if sess.opts.incremental.is_none() {
         return work_products;
@@ -1885,7 +1885,7 @@ pub struct OngoingCodegen<B: ExtraBackendMethods> {
 }
 
 impl<B: ExtraBackendMethods> OngoingCodegen<B> {
-    pub fn join(self, sess: &Session) -> (CodegenResults, FxHashMap<WorkProductId, WorkProduct>) {
+    pub fn join(self, sess: &Session) -> (CodegenResults, FxIndexMap<WorkProductId, WorkProduct>) {
         let _timer = sess.timer("finish_ongoing_codegen");
 
         self.shared_emitter_main.check(sess, true);
diff --git a/compiler/rustc_codegen_ssa/src/traits/backend.rs b/compiler/rustc_codegen_ssa/src/traits/backend.rs
index d83bfc74082f6c9764db6c435e93fd24263d16bf..b3c9ecf8b938b71e19c6b573cf368a59ac6dd811 100644
--- a/compiler/rustc_codegen_ssa/src/traits/backend.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/backend.rs
@@ -6,7 +6,7 @@
 use crate::{CodegenResults, ModuleCodegen};
 
 use rustc_ast::expand::allocator::AllocatorKind;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_errors::ErrorGuaranteed;
 use rustc_metadata::EncodedMetadata;
@@ -101,7 +101,7 @@ fn join_codegen(
         ongoing_codegen: Box<dyn Any>,
         sess: &Session,
         outputs: &OutputFilenames,
-    ) -> Result<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>), ErrorGuaranteed>;
+    ) -> Result<(CodegenResults, FxIndexMap<WorkProductId, WorkProduct>), ErrorGuaranteed>;
 
     /// This is called on the returned `Box<dyn Any>` from `join_codegen`
     ///
diff --git a/compiler/rustc_incremental/src/assert_dep_graph.rs b/compiler/rustc_incremental/src/assert_dep_graph.rs
index 22bd12f2e63616cb48508fc621d6e417ecffb0ee..52a84b204d00bf6f6a0e3a3727da35673d3809a1 100644
--- a/compiler/rustc_incremental/src/assert_dep_graph.rs
+++ b/compiler/rustc_incremental/src/assert_dep_graph.rs
@@ -35,7 +35,7 @@
 
 use crate::errors;
 use rustc_ast as ast;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::graph::implementation::{Direction, NodeIndex, INCOMING, OUTGOING};
 use rustc_graphviz as dot;
 use rustc_hir as hir;
@@ -258,7 +258,7 @@ fn dump_graph(query: &DepGraphQuery) {
 }
 
 #[allow(missing_docs)]
-pub struct GraphvizDepGraph(FxHashSet<DepKind>, Vec<(DepKind, DepKind)>);
+pub struct GraphvizDepGraph(FxIndexSet<DepKind>, Vec<(DepKind, DepKind)>);
 
 impl<'a> dot::GraphWalk<'a> for GraphvizDepGraph {
     type Node = DepKind;
@@ -303,7 +303,7 @@ fn node_label(&self, n: &DepKind) -> dot::LabelText<'_> {
 fn node_set<'q>(
     query: &'q DepGraphQuery,
     filter: &DepNodeFilter,
-) -> Option<FxHashSet<&'q DepNode>> {
+) -> Option<FxIndexSet<&'q DepNode>> {
     debug!("node_set(filter={:?})", filter);
 
     if filter.accepts_all() {
@@ -315,9 +315,9 @@ fn node_set<'q>(
 
 fn filter_nodes<'q>(
     query: &'q DepGraphQuery,
-    sources: &Option<FxHashSet<&'q DepNode>>,
-    targets: &Option<FxHashSet<&'q DepNode>>,
-) -> FxHashSet<DepKind> {
+    sources: &Option<FxIndexSet<&'q DepNode>>,
+    targets: &Option<FxIndexSet<&'q DepNode>>,
+) -> FxIndexSet<DepKind> {
     if let Some(sources) = sources {
         if let Some(targets) = targets {
             walk_between(query, sources, targets)
@@ -333,10 +333,10 @@ fn filter_nodes<'q>(
 
 fn walk_nodes<'q>(
     query: &'q DepGraphQuery,
-    starts: &FxHashSet<&'q DepNode>,
+    starts: &FxIndexSet<&'q DepNode>,
     direction: Direction,
-) -> FxHashSet<DepKind> {
-    let mut set = FxHashSet::default();
+) -> FxIndexSet<DepKind> {
+    let mut set = FxIndexSet::default();
     for &start in starts {
         debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
         if set.insert(start.kind) {
@@ -357,9 +357,9 @@ fn walk_nodes<'q>(
 
 fn walk_between<'q>(
     query: &'q DepGraphQuery,
-    sources: &FxHashSet<&'q DepNode>,
-    targets: &FxHashSet<&'q DepNode>,
-) -> FxHashSet<DepKind> {
+    sources: &FxIndexSet<&'q DepNode>,
+    targets: &FxIndexSet<&'q DepNode>,
+) -> FxIndexSet<DepKind> {
     // This is a bit tricky. We want to include a node only if it is:
     // (a) reachable from a source and (b) will reach a target. And we
     // have to be careful about cycles etc. Luckily efficiency is not
@@ -426,8 +426,8 @@ fn recurse(query: &DepGraphQuery, node_states: &mut [State], node: NodeIndex) ->
     }
 }
 
-fn filter_edges(query: &DepGraphQuery, nodes: &FxHashSet<DepKind>) -> Vec<(DepKind, DepKind)> {
-    let uniq: FxHashSet<_> = query
+fn filter_edges(query: &DepGraphQuery, nodes: &FxIndexSet<DepKind>) -> Vec<(DepKind, DepKind)> {
+    let uniq: FxIndexSet<_> = query
         .edges()
         .into_iter()
         .map(|(s, t)| (s.kind, t.kind))
diff --git a/compiler/rustc_incremental/src/assert_module_sources.rs b/compiler/rustc_incremental/src/assert_module_sources.rs
index c550e553bb032990d92d9e19947a0b4d41072163..82c787605d7d3b06ac19896679998059edffbfcd 100644
--- a/compiler/rustc_incremental/src/assert_module_sources.rs
+++ b/compiler/rustc_incremental/src/assert_module_sources.rs
@@ -24,7 +24,7 @@
 
 use crate::errors;
 use rustc_ast as ast;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
 use rustc_middle::ty::TyCtxt;
@@ -52,7 +52,7 @@ pub fn assert_module_sources(tcx: TyCtxt<'_>) {
 
 struct AssertModuleSource<'tcx> {
     tcx: TyCtxt<'tcx>,
-    available_cgus: FxHashSet<Symbol>,
+    available_cgus: FxIndexSet<Symbol>,
 }
 
 impl<'tcx> AssertModuleSource<'tcx> {
diff --git a/compiler/rustc_incremental/src/lib.rs b/compiler/rustc_incremental/src/lib.rs
index 11710c368cefea794de1fcdc081ba9fb94be8a1e..b9171fad55ba335aca180d9be2c62a1f5faa9753 100644
--- a/compiler/rustc_incremental/src/lib.rs
+++ b/compiler/rustc_incremental/src/lib.rs
@@ -4,7 +4,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(never_type)]
 #![recursion_limit = "256"]
-#![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index 43274091cb8733d5c63a434db93e5b8a14a25ef1..848b81b9d3496b2bbc20a1922735c95e625c92b2 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -21,7 +21,7 @@
 
 use crate::errors;
 use rustc_ast::{self as ast, Attribute, NestedMetaItem};
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit;
 use rustc_hir::Node as HirNode;
@@ -125,7 +125,7 @@
 //
 //     type_of for these.
 
-type Labels = FxHashSet<String>;
+type Labels = FxIndexSet<String>;
 
 /// Represents the requested configuration by rustc_clean/dirty
 struct Assertion {
diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
index e3c688b3e98cbe3a7cb17048e114b8acfcd4a878..463481f16f371068ce94786cb19bb63a0e751358 100644
--- a/compiler/rustc_incremental/src/persist/fs.rs
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -104,7 +104,7 @@
 //! implemented.
 
 use crate::errors;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::{base_n, flock};
 use rustc_errors::ErrorGuaranteed;
@@ -635,8 +635,8 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
 
     // First do a pass over the crate directory, collecting lock files and
     // session directories
-    let mut session_directories = FxHashSet::default();
-    let mut lock_files = FxHashSet::default();
+    let mut session_directories = FxIndexSet::default();
+    let mut lock_files = FxIndexSet::default();
 
     for dir_entry in crate_directory.read_dir()? {
         let Ok(dir_entry) = dir_entry else {
@@ -659,7 +659,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
     }
 
     // Now map from lock files to session directories
-    let lock_file_to_session_dir: FxHashMap<String, Option<String>> = lock_files
+    let lock_file_to_session_dir: FxIndexMap<String, Option<String>> = lock_files
         .into_iter()
         .map(|lock_file_name| {
             assert!(lock_file_name.ends_with(LOCK_FILE_EXT));
@@ -705,7 +705,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
     }
 
     // Filter out `None` directories
-    let lock_file_to_session_dir: FxHashMap<String, String> = lock_file_to_session_dir
+    let lock_file_to_session_dir: FxIndexMap<String, String> = lock_file_to_session_dir
         .into_iter()
         .filter_map(|(lock_file_name, directory_name)| directory_name.map(|n| (lock_file_name, n)))
         .collect();
@@ -846,7 +846,7 @@ fn delete_old(sess: &Session, path: &Path) {
 
 fn all_except_most_recent(
     deletion_candidates: Vec<(SystemTime, PathBuf, Option<flock::Lock>)>,
-) -> FxHashMap<PathBuf, Option<flock::Lock>> {
+) -> FxIndexMap<PathBuf, Option<flock::Lock>> {
     let most_recent = deletion_candidates.iter().map(|&(timestamp, ..)| timestamp).max();
 
     if let Some(most_recent) = most_recent {
@@ -856,7 +856,7 @@ fn all_except_most_recent(
             .map(|(_, path, lock)| (path, lock))
             .collect()
     } else {
-        FxHashMap::default()
+        FxIndexMap::default()
     }
 }
 
diff --git a/compiler/rustc_incremental/src/persist/load.rs b/compiler/rustc_incremental/src/persist/load.rs
index a4407a93ff3ba18f35450a86898e53d5b43802f8..0f7db109127979301eb7fc0cc6f688f965782825 100644
--- a/compiler/rustc_incremental/src/persist/load.rs
+++ b/compiler/rustc_incremental/src/persist/load.rs
@@ -1,7 +1,7 @@
 //! Code to save/load the dep-graph from files.
 
 use crate::errors;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::memmap::Mmap;
 use rustc_middle::dep_graph::{SerializedDepGraph, WorkProduct, WorkProductId};
 use rustc_middle::query::on_disk_cache::OnDiskCache;
@@ -16,7 +16,7 @@
 use super::fs::*;
 use super::work_product;
 
-type WorkProductMap = FxHashMap<WorkProductId, WorkProduct>;
+type WorkProductMap = FxIndexMap<WorkProductId, WorkProduct>;
 
 #[derive(Debug)]
 /// Represents the result of an attempt to load incremental compilation data.
@@ -147,7 +147,7 @@ pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
     let report_incremental_info = sess.opts.unstable_opts.incremental_info;
     let expected_hash = sess.opts.dep_tracking_hash(false);
 
-    let mut prev_work_products = FxHashMap::default();
+    let mut prev_work_products = FxIndexMap::default();
 
     // If we are only building with -Zquery-dep-graph but without an actual
     // incr. comp. session directory, we skip this. Otherwise we'd fail
diff --git a/compiler/rustc_incremental/src/persist/save.rs b/compiler/rustc_incremental/src/persist/save.rs
index 7376be6be8b8a85d70d91b1aa8d354391c20cb76..bcffba466413cf2ecbae6a74b7db7e5cf6782b19 100644
--- a/compiler/rustc_incremental/src/persist/save.rs
+++ b/compiler/rustc_incremental/src/persist/save.rs
@@ -1,5 +1,5 @@
 use crate::errors;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::join;
 use rustc_middle::dep_graph::{DepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
 use rustc_middle::ty::TyCtxt;
@@ -79,7 +79,7 @@ pub fn save_dep_graph(tcx: TyCtxt<'_>) {
 pub fn save_work_product_index(
     sess: &Session,
     dep_graph: &DepGraph,
-    new_work_products: FxHashMap<WorkProductId, WorkProduct>,
+    new_work_products: FxIndexMap<WorkProductId, WorkProduct>,
 ) {
     if sess.opts.incremental.is_none() {
         return;
@@ -119,7 +119,7 @@ pub fn save_work_product_index(
 }
 
 fn encode_work_product_index(
-    work_products: &FxHashMap<WorkProductId, WorkProduct>,
+    work_products: &FxIndexMap<WorkProductId, WorkProduct>,
     encoder: &mut FileEncoder,
 ) {
     let serialized_products: Vec<_> = work_products
@@ -146,7 +146,7 @@ fn encode_query_cache(tcx: TyCtxt<'_>, encoder: FileEncoder) -> FileEncodeResult
 pub fn build_dep_graph(
     sess: &Session,
     prev_graph: SerializedDepGraph,
-    prev_work_products: FxHashMap<WorkProductId, WorkProduct>,
+    prev_work_products: FxIndexMap<WorkProductId, WorkProduct>,
 ) -> Option<DepGraph> {
     if sess.opts.incremental.is_none() {
         // No incremental compilation.
diff --git a/compiler/rustc_incremental/src/persist/work_product.rs b/compiler/rustc_incremental/src/persist/work_product.rs
index dc98fbeb0d1669f9bbcd54dd3e392ca0fdc4ea92..a1dc78596a9ef8e4cdc385ed7ee16ec4f0186b72 100644
--- a/compiler/rustc_incremental/src/persist/work_product.rs
+++ b/compiler/rustc_incremental/src/persist/work_product.rs
@@ -4,7 +4,7 @@
 
 use crate::errors;
 use crate::persist::fs::*;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_fs_util::link_or_copy;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_session::Session;
@@ -20,7 +20,7 @@ pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
     debug!(?cgu_name, ?files);
     sess.opts.incremental.as_ref()?;
 
-    let mut saved_files = FxHashMap::default();
+    let mut saved_files = FxIndexMap::default();
     for (ext, path) in files {
         let file_name = format!("{cgu_name}.{ext}");
         let path_in_incr_dir = in_incr_comp_dir_sess(sess, &file_name);
diff --git a/compiler/rustc_query_system/src/dep_graph/graph.rs b/compiler/rustc_query_system/src/dep_graph/graph.rs
index c0d7386dd6adb88cc224b03177ab984a879406c7..54eaa1d4a7f99ba77526413888a191f273d674d0 100644
--- a/compiler/rustc_query_system/src/dep_graph/graph.rs
+++ b/compiler/rustc_query_system/src/dep_graph/graph.rs
@@ -1,6 +1,6 @@
 use parking_lot::Mutex;
 use rustc_data_structures::fingerprint::Fingerprint;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_data_structures::profiling::{EventId, QueryInvocationId, SelfProfilerRef};
 use rustc_data_structures::sharded::{self, Sharded};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -93,7 +93,7 @@ pub struct DepGraphData<K: DepKind> {
     /// things available to us. If we find that they are not dirty, we
     /// load the path to the file storing those work-products here into
     /// this map. We can later look for and extract that data.
-    previous_work_products: FxHashMap<WorkProductId, WorkProduct>,
+    previous_work_products: FxIndexMap<WorkProductId, WorkProduct>,
 
     dep_node_debug: Lock<FxHashMap<DepNode<K>, String>>,
 
@@ -116,7 +116,7 @@ impl<K: DepKind> DepGraph<K> {
     pub fn new(
         profiler: &SelfProfilerRef,
         prev_graph: SerializedDepGraph<K>,
-        prev_work_products: FxHashMap<WorkProductId, WorkProduct>,
+        prev_work_products: FxIndexMap<WorkProductId, WorkProduct>,
         encoder: FileEncoder,
         record_graph: bool,
         record_stats: bool,
@@ -688,7 +688,7 @@ pub fn previous_work_product(&self, v: &WorkProductId) -> Option<WorkProduct> {
 
     /// Access the map of work-products created during the cached run. Only
     /// used during saving of the dep-graph.
-    pub fn previous_work_products(&self) -> &FxHashMap<WorkProductId, WorkProduct> {
+    pub fn previous_work_products(&self) -> &FxIndexMap<WorkProductId, WorkProduct> {
         &self.data.as_ref().unwrap().previous_work_products
     }
 
@@ -1048,7 +1048,7 @@ pub struct WorkProduct {
     ///
     /// By convention, file extensions are currently used as identifiers, i.e. the key "o" maps to
     /// the object file's path, and "dwo" to the dwarf object file's path.
-    pub saved_files: FxHashMap<String, String>,
+    pub saved_files: FxIndexMap<String, String>,
 }
 
 // Index type for `DepNodeData`'s edges.