3v4l.org

run code in 500+ PHP versions simultaneously
<?php interface Foo { function f(): mixed; } class Bar implements Foo { function f(): array { return []; } }
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.31, 8.3.0 - 8.3.31, 8.4.1 - 8.4.22, 8.5.0 - 8.5.7
Output for 7.4.0 - 7.4.33
Fatal error: Declaration of Bar::f(): array must be compatible with Foo::f(): mixed in /in/CYkJl on line 10
Process exited with code 255.
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101.24 ms | 1257 KiB | 4 Q