Unused parameters in methods in abstract classes

[jrfnl]

Abstract classes can contain abstract methods which are required to be overloaded, but they can also contain empty methods which are optional to overload.

abstract class Foo
{
    // Required to be overloaded.
    abstract public function bar($param);

    // Optional to be overloaded.
    public function baz($param) {
    }
}

This standard will throw a Unused function parameter $param.(VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable) warning for the second method bax().

While technically correct, IMHO it would be sane to make an exception for these kind of "optional overload" (empty) methods in abstract classes.

[sirbrillig]

I agree. Maybe something like "if the variable is an argument of a function that is a method of an abstract class and the method body is empty, then do not mark unused".

[jrfnl]

Just thinking - maybe it should be: ""if the variable is an argument of a function that is a method of an abstract class and the method body is empty or only contains return;, then do not mark unused"."

[lkraav]

Indeed, I think I'm running into an abstract class method defined as abstract public function decompress( $compressed_item, $compressed_data_layer );, where we don't use $compressed_data_layer, but need to include it to match overload signature.