From 1f87a09503c480ec6b155267664e85ca2bdb7904 Mon Sep 17 00:00:00 2001
From: Tim Ledbetter <tim.ledbetter@ladybird.org>
Date: Fri, 31 Jan 2025 09:27:05 +0000
Subject: [PATCH] AK: Allow `as_if` to perform dynamic cast when necessary

This means that if `is<OutputType>(x)` is true, that
`as_if<OutputType>(x)` should always succeed.
---
 AK/TypeCasts.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/AK/TypeCasts.h b/AK/TypeCasts.h
index 4a2c2de6218..0ee0cb5fb82 100644
--- a/AK/TypeCasts.h
+++ b/AK/TypeCasts.h
@@ -56,7 +56,11 @@ ALWAYS_INLINE CopyConst<InputType, OutputType>* as_if(InputType& input)
 {
     if (!is<OutputType>(input))
         return nullptr;
-    return static_cast<CopyConst<InputType, OutputType>*>(&input);
+    if constexpr (IsBaseOf<InputType, OutputType>) {
+        return static_cast<CopyConst<InputType, OutputType>*>(&input);
+    } else {
+        return dynamic_cast<CopyConst<InputType, OutputType>*>(&input);
+    }
 }
 
 template<typename OutputType, typename InputType>