global old solver cache: use `TypingEnv`

1 files changed, 41 insertions, 20 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 98cddc6bb5c..3b64a47181a 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1310,13 +1310,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) -> Option<EvaluationResult> {
-        let tcx = self.tcx();
+        let infcx = self.infcx;
+        let tcx = infcx.tcx;
         if self.can_use_global_caches(param_env, trait_pred) {
-            if let Some(res) = tcx.evaluation_cache.get(&(param_env, trait_pred), tcx) {
-                return Some(res);
+            let key = (infcx.typing_env(param_env), trait_pred);
+            if let Some(res) = tcx.evaluation_cache.get(&key, tcx) {
+                Some(res)
+            } else {
+                debug_assert_eq!(infcx.evaluation_cache.get(&(param_env, trait_pred), tcx), None);
+                None
             }
+        } else {
+            self.infcx.evaluation_cache.get(&(param_env, trait_pred), tcx)
         }
-        self.infcx.evaluation_cache.get(&(param_env, trait_pred), tcx)
     }
 
     fn insert_evaluation_cache(
@@ -1332,18 +1338,21 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             return;
         }
 
-        if self.can_use_global_caches(param_env, trait_pred) && !trait_pred.has_infer() {
+        let infcx = self.infcx;
+        let tcx = infcx.tcx;
+        if self.can_use_global_caches(param_env, trait_pred) {
             debug!(?trait_pred, ?result, "insert_evaluation_cache global");
             // This may overwrite the cache with the same value
-            // FIXME: Due to #50507 this overwrites the different values
-            // This should be changed to use HashMapExt::insert_same
-            // when that is fixed
-            self.tcx().evaluation_cache.insert((param_env, trait_pred), dep_node, result);
+            tcx.evaluation_cache.insert(
+                (infcx.typing_env(param_env), trait_pred),
+                dep_node,
+                result,
+            );
             return;
+        } else {
+            debug!(?trait_pred, ?result, "insert_evaluation_cache local");
+            self.infcx.evaluation_cache.insert((param_env, trait_pred), dep_node, result);
         }
-
-        debug!(?trait_pred, ?result, "insert_evaluation_cache");
-        self.infcx.evaluation_cache.insert((param_env, trait_pred), dep_node, result);
     }
 
     fn check_recursion_depth<T>(
@@ -1485,7 +1494,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // If there are any inference variables in the `ParamEnv`, then we
         // always use a cache local to this particular scope. Otherwise, we
         // switch to a global cache.
-        if param_env.has_infer() {
+        if param_env.has_infer() || pred.has_infer() {
             return false;
         }
 
@@ -1522,15 +1531,20 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         cache_fresh_trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) -> Option<SelectionResult<'tcx, SelectionCandidate<'tcx>>> {
-        let tcx = self.tcx();
+        let infcx = self.infcx;
+        let tcx = infcx.tcx;
         let pred = cache_fresh_trait_pred.skip_binder();
 
         if self.can_use_global_caches(param_env, cache_fresh_trait_pred) {
-            if let Some(res) = tcx.selection_cache.get(&(param_env, pred), tcx) {
-                return Some(res);
+            if let Some(res) = tcx.selection_cache.get(&(infcx.typing_env(param_env), pred), tcx) {
+                Some(res)
+            } else {
+                debug_assert_eq!(infcx.selection_cache.get(&(param_env, pred), tcx), None);
+                None
             }
+        } else {
+            infcx.selection_cache.get(&(param_env, pred), tcx)
         }
-        self.infcx.selection_cache.get(&(param_env, pred), tcx)
     }
 
     /// Determines whether can we safely cache the result
@@ -1567,7 +1581,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         dep_node: DepNodeIndex,
         candidate: SelectionResult<'tcx, SelectionCandidate<'tcx>>,
     ) {
-        let tcx = self.tcx();
+        let infcx = self.infcx;
+        let tcx = infcx.tcx;
         let pred = cache_fresh_trait_pred.skip_binder();
 
         if !self.can_cache_candidate(&candidate) {
@@ -1578,10 +1593,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         if self.can_use_global_caches(param_env, cache_fresh_trait_pred) {
             if let Err(Overflow(OverflowError::Canonical)) = candidate {
                 // Don't cache overflow globally; we only produce this in certain modes.
-            } else if !pred.has_infer() && !candidate.has_infer() {
+            } else {
                 debug!(?pred, ?candidate, "insert_candidate_cache global");
+                debug_assert!(!candidate.has_infer());
+
                 // This may overwrite the cache with the same value.
-                tcx.selection_cache.insert((param_env, pred), dep_node, candidate);
+                tcx.selection_cache.insert(
+                    (infcx.typing_env(param_env), pred),
+                    dep_node,
+                    candidate,
+                );
                 return;
             }
         }