From 97623b4e727628c6036bddb12ca36555e7e36d85 Mon Sep 17 00:00:00 2001
From: Jeong YunWon <jeong@youknowone.org>
Date: Fri, 15 Oct 2021 05:02:13 +0900
Subject: [PATCH 1/2] Fix __hash__ not to perform unnecessary downcast

---
 vm/src/types/slot.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/vm/src/types/slot.rs b/vm/src/types/slot.rs
index 4ce18e15d4..fea9b2e091 100644
--- a/vm/src/types/slot.rs
+++ b/vm/src/types/slot.rs
@@ -486,8 +486,8 @@ pub trait Hashable: PyValue {
 
     #[inline]
     #[pymethod]
-    fn __hash__(zelf: PyRef<Self>, vm: &VirtualMachine) -> PyResult<PyHash> {
-        Self::hash(&zelf, vm)
+    fn __hash__(zelf: PyObjectRef, vm: &VirtualMachine) -> PyResult<PyHash> {
+        Self::slot_hash(&zelf, vm)
     }
 
     fn hash(zelf: &PyRef<Self>, vm: &VirtualMachine) -> PyResult<PyHash>;

From 42912a36a1ce33e4a6d47ed26d7b1cc5044d0790 Mon Sep 17 00:00:00 2001
From: Jeong YunWon <jeong@youknowone.org>
Date: Fri, 15 Oct 2021 16:31:31 +0900
Subject: [PATCH 2/2] No downcast for unhashable

---
 vm/src/types/slot.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/vm/src/types/slot.rs b/vm/src/types/slot.rs
index fea9b2e091..ea5a1449c3 100644
--- a/vm/src/types/slot.rs
+++ b/vm/src/types/slot.rs
@@ -499,8 +499,11 @@ impl<T> Hashable for T
 where
     T: Unhashable,
 {
-    fn hash(_zelf: &PyRef<Self>, vm: &VirtualMachine) -> PyResult<PyHash> {
-        Err(vm.new_type_error(format!("unhashable type: '{}'", _zelf.class().name())))
+    fn slot_hash(zelf: &PyObjectRef, vm: &VirtualMachine) -> PyResult<PyHash> {
+        Err(vm.new_type_error(format!("unhashable type: '{}'", zelf.class().name())))
+    }
+    fn hash(_zelf: &PyRef<Self>, _vm: &VirtualMachine) -> PyResult<PyHash> {
+        unreachable!("slot_hash is implemented for unhashable types");
     }
 }