Online PHP editor | output for TUbfJ

@ 2017-01-24T14:01:00Z

<?php

declare(strict_types=1);

interface I {
  public function example();
}
class A implements I {
  public function example(): int { return 123; } // compatible with I::example
}
class B extends A {
  public function example(): string { return "string"; } // compatible with I::example
}

function accepts_i_expects_any(I $i) {
  var_dump($i->example());
}
accepts_i_expects_any(new B); // receives string, no problem

function accepts_a_expects_int(A $a) {
  var_dump($a->example());
}
accepts_a_expects_int(new B); // receives string, problem

Output for 8.5.0 - 8.5.3: Fatal error: Declaration of B::example(): string must be compatible with A::example(): int in /in/TUbfJ on line 12 Stack trace: #0 {main}
Process exited with code 255.
Output for 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18: Fatal error: Declaration of B::example(): string must be compatible with A::example(): int in /in/TUbfJ on line 12
Process exited with code 255.
Output for 7.2.0 - 7.2.33, 7.3.0 - 7.3.33: Fatal error: Declaration of B::example(): string must be compatible with A::example(): int in /in/TUbfJ on line 11
Process exited with code 255.
Output for 7.0.0 - 7.0.20, 7.1.1 - 7.1.25: string(6) "string" string(6) "string"
Output for 7.1.0: Process exited with code 137.

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