3v4l.org

run code in 300+ PHP versions simultaneously
<?php interface I { function test(): int; } class A implements I { function test(): int {} } class B extends A { function test(): string {} } ?>
Output for 7.4.0 - 7.4.23, 8.0.0 - 8.0.11, 8.1rc1
Fatal error: Declaration of B::test(): string must be compatible with A::test(): int in /in/V71FR on line 16
Process exited with code 255.
Output for 7.2.0 - 7.2.33, 7.3.16 - 7.3.30
Fatal error: Declaration of B::test(): string must be compatible with A::test(): int in /in/V71FR on line 14
Process exited with code 255.
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.20
Fatal error: Declaration of B::test(): string must be compatible with I::test(): int in /in/V71FR on line 14
Process exited with code 255.

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