diff --git a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
index 385fab83b5..45e6e9fdfd 100644
--- a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
@@ -2192,6 +2192,13 @@ public function testBug13065(): void
 		$this->analyse([__DIR__ . '/data/bug-13065.php'], $errors);
 	}
 
+	public function testBug3506(): void
+	{
+		$this->checkExplicitMixed = true;
+		$this->checkImplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-3506.php'], []);
+	}
+
 	#[RequiresPhp('>= 8.0')]
 	public function testBug12317(): void
 	{
diff --git a/tests/PHPStan/Rules/Functions/data/bug-3506.php b/tests/PHPStan/Rules/Functions/data/bug-3506.php
new file mode 100644
index 0000000000..ef2eb53a25
--- /dev/null
+++ b/tests/PHPStan/Rules/Functions/data/bug-3506.php
@@ -0,0 +1,18 @@
+<?php declare(strict_types = 1);
+
+namespace Bug3506;
+
+class A {
+	/**
+	 * @phpstan-param \Closure(int, mixed...) : void $c
+	 */
+	function dummy(\Closure $c) : void{
+
+	}
+
+	function dummy2() : void{
+		$this->dummy(function(int $a, ...$args) : void{
+			var_dump(...$args);
+		});
+	}
+}