src/Reflection/Adapter/ReflectionClass.php
public function isSubclassOf($class)
    {
        $realParentClassNames = $this->betterReflectionClass->getParentClassNames();

        $parentClassNames = array_combine(array_map(static function (string $parentClassName) : string {
            return strtolower($parentClassName);
        }, $realParentClassNames), $realParentClassNames);

        $realParentClassName = $parentClassNames[strtolower($class)] ?? $class;

        return $this->betterReflectionClass->isSubclassOf($realParentClassName) || $this->implementsInterface($class);
    }
public function isSubclassOf($class)
    {
        $realParentClassNames = $this->betterReflectionClass->getParentClassNames();

        $parentClassNames = array_combine(array_map(static function (string $parentClassName) : string {
            return strtolower($parentClassName);
        }, $realParentClassNames), $realParentClassNames);

        $realParentClassName = $parentClassNames[strtolower($class)] ?? $class;

        return $this->betterReflectionClass->isSubclassOf($realParentClassName) || $this->implementsInterface($class);
    }
{@inheritDoc}