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run code in 300+ PHP versions simultaneously
<?php class A {public ?string $r = '';} class B extends A {public int|string $r;} //(new B)->r;
Output for 8.0.1 - 8.0.22, 8.1.0 - 8.1.9
Fatal error: Type of B::$r must be ?string (as in class A) in /in/APrsI on line 4
Process exited with code 255.
Output for 7.4.0 - 7.4.30
Parse error: syntax error, unexpected '|', expecting variable (T_VARIABLE) in /in/APrsI on line 4
Process exited with code 255.

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