Don't ICE when computing PointerLike trait when region vars are in param-env

2 files changed, 16 insertions, 10 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index dcfa33ae842..644bfd33970 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -177,14 +177,18 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
             return Err(NoSolution);
         }
 
-        if goal.predicate.self_ty().has_non_region_infer() {
+        // The regions of a type don't affect the size of the type
+        let tcx = ecx.tcx();
+        // We should erase regions from both the param-env and type, since both
+        // may have infer regions. Specifically, after canonicalizing and instantiating,
+        // early bound regions turn into region vars in both the new and old solver.
+        let key = tcx.erase_regions(goal.param_env.and(goal.predicate.self_ty()));
+        // But if there are inference variables, we have to wait until it's resolved.
+        if key.has_non_region_infer() {
             return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS);
         }
 
-        let tcx = ecx.tcx();
-        let self_ty = tcx.erase_regions(goal.predicate.self_ty());
-
-        if let Ok(layout) = tcx.layout_of(goal.param_env.and(self_ty))
+        if let Ok(layout) = tcx.layout_of(key)
             && layout.layout.is_pointer_like(&tcx.data_layout)
         {
             // FIXME: We could make this faster by making a no-constraints response
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index aa230936903..8bc82b9f549 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -967,16 +967,18 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     ) {
         // The regions of a type don't affect the size of the type
         let tcx = self.tcx();
-        let self_ty =
-            tcx.erase_regions(tcx.erase_late_bound_regions(obligation.predicate.self_ty()));
-
+        let self_ty = tcx.erase_late_bound_regions(obligation.predicate.self_ty());
+        // We should erase regions from both the param-env and type, since both
+        // may have infer regions. Specifically, after canonicalizing and instantiating,
+        // early bound regions turn into region vars in both the new and old solver.
+        let key = tcx.erase_regions(obligation.param_env.and(self_ty));
         // But if there are inference variables, we have to wait until it's resolved.
-        if self_ty.has_non_region_infer() {
+        if key.has_non_region_infer() {
             candidates.ambiguous = true;
             return;
         }
 
-        if let Ok(layout) = tcx.layout_of(obligation.param_env.and(self_ty))
+        if let Ok(layout) = tcx.layout_of(key)
             && layout.layout.is_pointer_like(&tcx.data_layout)
         {
             candidates.vec.push(BuiltinCandidate { has_nested: false });