improve caching

Author: lcnr

compiler/rustc_infer/src/infer/relate/type_relating.rs

@@ -85,7 +85,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for TypeRelating<'_, '_, 'tcx> {
         let a = infcx.shallow_resolve(a);
         let b = infcx.shallow_resolve(b);
 
-        if self.cache.contains(&(self.ambient_variance, a, b)) {
+        if infcx.next_trait_solver() && self.cache.contains(&(self.ambient_variance, a, b)) {
             return Ok(a);
         }
 
@@ -171,7 +171,9 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for TypeRelating<'_, '_, 'tcx> {
             }
         }
 
-        assert!(self.cache.insert((self.ambient_variance, a, b)));
+        if infcx.next_trait_solver() {
+            assert!(self.cache.insert((self.ambient_variance, a, b)));
+        }
 
         Ok(a)
     }

compiler/rustc_next_trait_solver/src/resolve.rs

@@ -1,4 +1,4 @@
-use rustc_data_structures::sso::SsoHashMap;
+use rustc_type_ir::data_structures::HashMap;
 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: SsoHashMap<I::Ty, I::Ty>,
+    cache: HashMap<I::Ty, I::Ty>,
 }
 
 impl<'a, D: SolverDelegate> EagerResolver<'a, D> {
@@ -31,11 +31,7 @@ impl<D: SolverDelegate<Interner = I>, I: Interner> TypeFolder<I> for EagerResolv
     }
 
     fn fold_ty(&mut self, t: I::Ty) -> I::Ty {
-        if let Some(&ty) = self.cache.get(&t) {
-            return ty;
-        }
-
-        let res = match t.kind() {
+        match t.kind() {
             ty::Infer(ty::TyVar(vid)) => {
                 let resolved = self.delegate.opportunistic_resolve_ty_var(vid);
                 if t != resolved && resolved.has_infer() {
@@ -48,15 +44,17 @@ impl<D: SolverDelegate<Interner = I>, I: Interner> TypeFolder<I> for EagerResolv
             ty::Infer(ty::FloatVar(vid)) => self.delegate.opportunistic_resolve_float_var(vid),
             _ => {
                 if t.has_infer() {
-                    t.super_fold_with(self)
+                    if let Some(&ty) = self.cache.get(&t) {
+                        return ty;
+                    }
+                    let res = t.super_fold_with(self);
+                    assert!(self.cache.insert(t, res).is_none());
+                    res
                 } else {
                     t
                 }
             }
-        };
-
-        assert!(self.cache.insert(t, res).is_none());
-        res
+        }
     }
 
     fn fold_region(&mut self, r: I::Region) -> I::Region {