diff --git a/resources/functionMap.php b/resources/functionMap.php
index 8e291259e0a..402720ffee8 100644
--- a/resources/functionMap.php
+++ b/resources/functionMap.php
@@ -8635,7 +8635,7 @@
 'Redis::sDiff' => ['__benevolent<Redis|list<string>|false>', 'key'=>'string', '...other_keys='=>'string'],
 'Redis::sDiffStore' => ['__benevolent<Redis|int|false>', 'dst'=>'string', 'key'=>'string', '...other_keys='=>'string'],
 'Redis::select' => ['__benevolent<Redis|bool>', 'db'=>'int'],
-'Redis::set' => ['__benevolent<Redis|string|bool>', 'key'=>'string', 'value'=>'mixed', 'options='=>'array'],
+'Redis::set' => ['__benevolent<Redis|string|bool>', 'key'=>'string', 'value'=>'mixed', 'options='=>'array|int|null'],
 'Redis::setBit' => ['__benevolent<Redis|int|bool>', 'key'=>'string', 'idx'=>'int', 'value'=>'bool'],
 'Redis::setex' => ['__benevolent<Redis|bool>', 'key'=>'string', 'expire'=>'int', 'value'=>'mixed'],
 'Redis::setnx' => ['__benevolent<Redis|bool>', 'key'=>'string', 'value'=>'mixed'],
diff --git a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
index e03a97fc739..67834e4c54f 100644
--- a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
+++ b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
@@ -4586,4 +4586,12 @@ public function testClassConstantWildcardArguments(): void
 		]);
 	}
 
+	public function testBug15393(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->analyse([__DIR__ . '/data/bug-15393.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Methods/data/bug-15393.php b/tests/PHPStan/Rules/Methods/data/bug-15393.php
new file mode 100644
index 00000000000..a4b74fb0ba5
--- /dev/null
+++ b/tests/PHPStan/Rules/Methods/data/bug-15393.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Bug15393;
+
+function doFoo(\Redis $redis): void
+{
+	$redis->set('key', 'value');
+	$redis->set('key', 'value', 3600);
+	$redis->set('key', 'value', ['nx', 'ex' => 3600]);
+	$redis->set('key', 'value', null);
+}