From a9dd08cbf0cde2bb9c6ad6c4a9ed99abca1fc6d5 Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Wed, 25 Sep 2024 14:58:42 +0200
Subject: [PATCH] SsoHashMap

---
 .../src/infer/relate/type_relating.rs         |  4 ++--
 compiler/rustc_infer/src/infer/resolve.rs     | 23 ++++++++-----------
 compiler/rustc_middle/src/ty/fold.rs          |  5 ++--
 .../rustc_next_trait_solver/src/resolve.rs    |  4 ++--
 4 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/compiler/rustc_infer/src/infer/relate/type_relating.rs b/compiler/rustc_infer/src/infer/relate/type_relating.rs
index 6167beccd8a5..d4ad9c383db3 100644
--- a/compiler/rustc_infer/src/infer/relate/type_relating.rs
+++ b/compiler/rustc_infer/src/infer/relate/type_relating.rs
@@ -1,4 +1,4 @@
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::sso::SsoHashSet;
 use rustc_middle::traits::solve::Goal;
 use rustc_middle::ty::relate::{
     Relate, RelateResult, TypeRelation, relate_args_invariantly, relate_args_with_variances,
@@ -17,7 +17,7 @@ pub struct TypeRelating<'combine, 'a, 'tcx> {
     fields: &'combine mut CombineFields<'a, 'tcx>,
     structurally_relate_aliases: StructurallyRelateAliases,
     ambient_variance: ty::Variance,
-    cache: FxHashSet<(ty::Variance, Ty<'tcx>, Ty<'tcx>)>,
+    cache: SsoHashSet<(ty::Variance, Ty<'tcx>, Ty<'tcx>)>,
 }
 
 impl<'combine, 'infcx, 'tcx> TypeRelating<'combine, 'infcx, 'tcx> {
diff --git a/compiler/rustc_infer/src/infer/resolve.rs b/compiler/rustc_infer/src/infer/resolve.rs
index 1a162c4dbcf9..b80406d197fa 100644
--- a/compiler/rustc_infer/src/infer/resolve.rs
+++ b/compiler/rustc_infer/src/infer/resolve.rs
@@ -1,4 +1,4 @@
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::sso::SsoHashMap;
 use rustc_middle::bug;
 use rustc_middle::ty::fold::{FallibleTypeFolder, TypeFolder, TypeSuperFoldable};
 use rustc_middle::ty::visit::TypeVisitableExt;
@@ -16,7 +16,7 @@ use super::{FixupError, FixupResult, InferCtxt};
 /// points for correctness.
 pub struct OpportunisticVarResolver<'a, 'tcx> {
     infcx: &'a InferCtxt<'tcx>,
-    cache: FxHashMap<Ty<'tcx>, Ty<'tcx>>,
+    cache: SsoHashMap<Ty<'tcx>, Ty<'tcx>>,
 }
 
 impl<'a, 'tcx> OpportunisticVarResolver<'a, 'tcx> {
@@ -33,19 +33,16 @@ impl<'a, 'tcx> TypeFolder<TyCtxt<'tcx>> for OpportunisticVarResolver<'a, 'tcx> {
 
     #[inline]
     fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
-        if let Some(&ty) = self.cache.get(&t) {
-            return ty;
-        }
-
-        let res = if !t.has_non_region_infer() {
+        if !t.has_non_region_infer() {
             t // micro-optimize -- if there is nothing in this type that this fold affects...
+        } else if let Some(&ty) = self.cache.get(&t) {
+            return ty;
         } else {
-            let t = self.infcx.shallow_resolve(t);
-            t.super_fold_with(self)
-        };
-
-        assert!(self.cache.insert(t, res).is_none());
-        res
+            let shallow = self.infcx.shallow_resolve(t);
+            let res = shallow.super_fold_with(self);
+            assert!(self.cache.insert(t, res).is_none());
+            res
+        }
     }
 
     fn fold_const(&mut self, ct: Const<'tcx>) -> Const<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index c98e5c26cd71..6884366e8fb6 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -1,4 +1,5 @@
-use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
+use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::sso::SsoHashMap;
 use rustc_hir::def_id::DefId;
 pub use rustc_type_ir::fold::{
     FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable, shift_region, shift_vars,
@@ -165,7 +166,7 @@ struct BoundVarReplacer<'tcx, D> {
 
     delegate: D,
 
-    cache: FxHashMap<(ty::DebruijnIndex, Ty<'tcx>), Ty<'tcx>>,
+    cache: SsoHashMap<(ty::DebruijnIndex, Ty<'tcx>), Ty<'tcx>>,
 }
 
 impl<'tcx, D: BoundVarReplacerDelegate<'tcx>> BoundVarReplacer<'tcx, D> {
diff --git a/compiler/rustc_next_trait_solver/src/resolve.rs b/compiler/rustc_next_trait_solver/src/resolve.rs
index 3b97028dbabf..f0fd79f6e481 100644
--- a/compiler/rustc_next_trait_solver/src/resolve.rs
+++ b/compiler/rustc_next_trait_solver/src/resolve.rs
@@ -1,4 +1,4 @@
-use rustc_type_ir::data_structures::HashMap;
+use rustc_data_structures::sso::SsoHashMap;
 use rustc_type_ir::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_type_ir::inherent::*;
 use rustc_type_ir::visit::TypeVisitableExt;
@@ -16,7 +16,7 @@ where
     I: Interner,
 {
     delegate: &'a D,
-    cache: HashMap<I::Ty, I::Ty>,
+    cache: SsoHashMap<I::Ty, I::Ty>,
 }
 
 impl<'a, D: SolverDelegate> EagerResolver<'a, D> {