3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php interface I { } interface C extends I { } interface BI { function x(): I; } class BC implements BI { function x(): C { } }
based on F5KKX
Output for 7.0.0 - 7.2.6
Fatal error: Declaration of BC::x(): C must be compatible with BI::x(): I in /in/GmCYq on line 13
Process exited with code 255.
Output for hhvm-3.15.4
Output for 5.6.0 - 5.6.30
Parse error: syntax error, unexpected ':', expecting ';' or '{' in /in/GmCYq on line 11
Process exited with code 255.