Added regression test

Author: staabm

tests/PHPStan/Rules/Properties/TypesAssignedToPropertiesRuleTest.php

@@ -779,4 +779,10 @@ public function testPropertyHooks(): void
 		]);
 	}
 
+	public function testBug11171(): void
+	{
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-11171.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Properties/data/bug-11171.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Bug11171;
+
+class TypeExpression
+{
+	public string $value;
+
+	/**
+	 * @var list<array{start_index: int, expression: self}>
+	 */
+	public array $innerTypeExpressions = [];
+
+	/**
+	 * @param \Closure(self): void $callback
+	 */
+	public function walkTypes(\Closure $callback): void
+	{
+		$startIndexOffset = 0;
+
+		foreach ($this->innerTypeExpressions as $k => ['start_index' => $startIndexOrig,
+				 'expression' => $inner,]) {
+			$this->innerTypeExpressions[$k]['start_index'] += $startIndexOffset;
+
+			$innerLengthOrig = \strlen($inner->value);
+
+			$inner->walkTypes($callback);
+
+			$this->value = substr_replace(
+				$this->value,
+				$inner->value,
+				$startIndexOrig + $startIndexOffset,
+				$innerLengthOrig
+			);
+
+			$startIndexOffset += \strlen($inner->value) - $innerLengthOrig;
+		}
+
+		$callback($this);
+	}
+}