From f62e5406f247e45df05a4f27b2fbd178f9851b9d Mon Sep 17 00:00:00 2001
From: David Peter <sharkdp@users.noreply.github.com>
Date: Thu, 20 Feb 2025 23:06:11 +0100
Subject: [PATCH] [red-knot] Short-circuit bool calls on bool (#16292)

## Summary

This avoids looking up `__bool__` on class `bool` for every
`Type::Instance(bool).bool()` call. 1% performance win on cold cache, 4%
win on incremental performance.
---
 crates/red_knot_python_semantic/src/types.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/crates/red_knot_python_semantic/src/types.rs b/crates/red_knot_python_semantic/src/types.rs
index 625a48689f..76b55cea27 100644
--- a/crates/red_knot_python_semantic/src/types.rs
+++ b/crates/red_knot_python_semantic/src/types.rs
@@ -1452,7 +1452,9 @@ impl<'db> Type<'db> {
             Type::AlwaysTruthy => Truthiness::AlwaysTrue,
             Type::AlwaysFalsy => Truthiness::AlwaysFalse,
             instance_ty @ Type::Instance(InstanceType { class }) => {
-                if class.is_known(db, KnownClass::NoneType) {
+                if class.is_known(db, KnownClass::Bool) {
+                    Truthiness::Ambiguous
+                } else if class.is_known(db, KnownClass::NoneType) {
                     Truthiness::AlwaysFalse
                 } else {
                     // We only check the `__bool__` method for truth testing, even though at