1--TEST-- 2Compound assignment operator on static property holding ref 3--FILE-- 4<?php declare(strict_types=1); 5 6class Test { 7 public static int $intProp = 123; 8 public static $prop; 9} 10 11Test::$prop =& Test::$intProp; 12try { 13 Test::$prop .= "foobar"; 14} catch (TypeError $e) { 15 echo $e->getMessage(), "\n"; 16} 17var_dump(Test::$prop, Test::$intProp); 18?> 19--EXPECT-- 20Cannot assign string to reference held by property Test::$intProp of type int 21int(123) 22int(123) 23