constructor.unusedParameter

Code example

<?php declare(strict_types = 1);

class Foo
{
	public function __construct(int $value, string $unused)
	{
		echo $value;
	}
}

Why is it reported?

The constructor has a parameter that is never used within the constructor body. In the example above, the parameter $unused is declared but never referenced.

This only applies to non-promoted parameters. Constructor-promoted parameters (those with visibility keywords like public, protected, or private) are excluded because they serve the purpose of initializing properties.

How to fix it

Remove the unused parameter if it is not needed:

 <?php declare(strict_types = 1);

 class Foo
 {
-	public function __construct(int $value, string $unused)
+	public function __construct(int $value)
 	{
 		echo $value;
 	}
 }

Or use the parameter in the constructor body. Alternatively, promote it to a property:

 <?php declare(strict_types = 1);

 class Foo
 {
-	public function __construct(int $value, string $unused)
+	public function __construct(int $value, private string $unused)
 	{
 		echo $value;
 	}
 }