From 138cfab9f7af26a7871fc0c3cff0888b1a9a7c3a Mon Sep 17 00:00:00 2001
From: Michael Woerister <michaelwoerister@posteo>
Date: Thu, 21 Dec 2023 11:10:30 +0100
Subject: [PATCH] Make iteration order of crate_inherent_impls query result
 stable.

---
 compiler/rustc_metadata/src/rmeta/encoder.rs | 12 +++---------
 compiler/rustc_middle/src/ty/mod.rs          |  3 ++-
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index d761439f4ef..1d12b853b53 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -2,10 +2,8 @@ use crate::errors::{FailCreateFileEncoder, FailWriteFile};
 use crate::rmeta::*;
 
 use rustc_ast::Attribute;
-use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::memmap::{Mmap, MmapMut};
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::{join, par_for_each_in, Lrc};
 use rustc_data_structures::temp_dir::MaybeTempDir;
 use rustc_hir as hir;
@@ -2034,14 +2032,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     fn encode_incoherent_impls(&mut self) -> LazyArray<IncoherentImpls> {
         empty_proc_macro!(self);
         let tcx = self.tcx;
-        let mut all_impls: Vec<_> = tcx.crate_inherent_impls(()).incoherent_impls.iter().collect();
-        tcx.with_stable_hashing_context(|mut ctx| {
-            all_impls.sort_by_cached_key(|&(&simp, _)| {
-                let mut hasher = StableHasher::new();
-                simp.hash_stable(&mut ctx, &mut hasher);
-                hasher.finish::<Fingerprint>()
-            })
+        let all_impls = tcx.with_stable_hashing_context(|hcx| {
+            tcx.crate_inherent_impls(()).incoherent_impls.to_sorted(&hcx, true)
         });
+
         let all_impls: Vec<_> = all_impls
             .into_iter()
             .map(|(&simp, impls)| {
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 757d3337afc..1ba9d56df7c 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -38,6 +38,7 @@ use rustc_data_structures::intern::Interned;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::steal::Steal;
 use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
+use rustc_data_structures::unord::UnordMap;
 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, DocLinkResMap, LifetimeRes, Res};
@@ -2658,7 +2659,7 @@ pub fn provide(providers: &mut Providers) {
 #[derive(Clone, Debug, Default, HashStable)]
 pub struct CrateInherentImpls {
     pub inherent_impls: LocalDefIdMap<Vec<DefId>>,
-    pub incoherent_impls: FxHashMap<SimplifiedType, Vec<LocalDefId>>,
+    pub incoherent_impls: UnordMap<SimplifiedType, Vec<LocalDefId>>,
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, HashStable)]