Fixed mixed type not considered nullable

Author: ondrejmirtes

composer.lock

@@ -587,6 +587,10 @@ public function dataFileAsserts(): iterable
 			yield from $this->gatherAssertTypes(__DIR__ . '/data/enums-import-alias.php');
 		}
 
+		if (PHP_VERSION_ID >= 80000) {
+			yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6293.php');
+		}
+
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/classPhpDocs-phpstanPropertyPrefix.php');
 	}
 

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Bug6239;
+
+use function PHPStan\Testing\assertNativeType;
+use function PHPStan\Testing\assertType;
+
+class UnionWithNullFails
+{
+	/**
+	 * @param int|null|bool $value
+	 */
+	public function withPhpDoc(mixed $value): void
+	{
+		assertType('bool|int|null', $value);
+		assertNativeType('mixed', $value);
+	}
+
+	public function doFoo(): void
+	{
+		$this->withPhpDoc(null);
+	}
+}

tests/PHPStan/Analyser/data/bug-6293.php

@@ -2273,4 +2273,12 @@ public function testEnums(): void
 		]);
 	}
 
+	public function testBug6239(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->analyse([__DIR__ . '/../../Analyser/data/bug-6293.php'], []);
+	}
+
 }