Regression test

Closes phpstan/phpstan#6773

tests/PHPStan/Rules/Properties/ReadOnlyPropertyAssignRuleTest.php

@@ -140,4 +140,13 @@ public function testReadOnlyClasses(): void
 		]);
 	}
 
+	public function testBug6773(): void
+	{
+		if (PHP_VERSION_ID < 80100) {
+			$this->markTestSkipped('Test requires PHP 8.1.');
+		}
+
+		$this->analyse([__DIR__ . '/data/bug-6773.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Properties/data/bug-6773.php

@@ -0,0 +1,18 @@
+<?php // lint >= 8.1
+
+namespace Bug6773;
+
+final class Repository
+{
+	/**
+	 * @param array<string, string> $data
+	 */
+	public function __construct(private readonly array $data)
+	{
+	}
+
+	public function remove(string $key): void
+	{
+		unset($this->data[$key]);
+	}
+}