UnusedFunctionCall

Emitted when --find-dead-code is turned on and Psalm finds a function call whose return value is not used anywhere

<?php

$a = strlen("hello");
strlen("goodbye"); // unused
echo $a;

It is also emitted, regardless of --find-dead-code, when the return value of a function annotated with PHP 8.5's #[\NoDiscard] attribute is discarded. Casting the call to (void) intentionally discards the value without triggering the issue.