3v4l.org

run code in 300+ PHP versions simultaneously
<?php abstract class A { abstract public function foo(A $a): A; } class B extends A { public function foo(B $b): B { } }
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.6
Fatal error: Declaration of B::foo(B $b): B must be compatible with A::foo(A $a): A in /in/jSmAN on line 11
Process exited with code 255.
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