detect unused parameters

[staabm]

I think this extension has all the information available to decide that optional method parameters are never used from a caller point of view and therefore mark them as obsolete.

e.g.

Class X {
  public function doFoo($a, $b, $c = null, $d = 123) {
  }
}

$x = new X();
$x->doFoo(1, 2);
$x->doFoo(3, 4);

-> since no calls exist which provide a value for $c and/or $d, both parameters are "unused" and could be turned into local variables or even removed altogether.

is this something you would accept as a PR?

[TomasVotruba]

Thanks for proposal, this would be out of simple scope of this package. It could be great separate package, as you can look for unused variables, assigns, etc. Still I think this is already handled by PHPStan and Rector well :+1: