match.void

Code example

<?php declare(strict_types = 1);

class Foo
{
	public function doFoo(): void
	{
	}

	public function doBar(int $i): void
	{
		$a = match ($i) {
			1 => $this->doFoo(),
			2 => $this->doFoo(),
			default => $this->doFoo(),
		};
	}
}

Why is it reported?

The result of a match expression is being used (assigned to a variable, passed as an argument, etc.), but all arms of the match return void. A void return type means the method does not return a meaningful value, so the result of this match expression is always void and cannot be meaningfully used.

This typically indicates a logic error -- either the match arms should call methods that return values, or the match result should not be used.

How to fix it

If the match is only used for side effects, use it as a standalone statement without assigning the result:

 public function doBar(int $i): void
 {
-	$a = match ($i) {
+	match ($i) {
 		1 => $this->doFoo(),
 		2 => $this->doFoo(),
 		default => $this->doFoo(),
 	};
 }

Alternatively, if a value is needed, call methods that return meaningful values:

-	public function doFoo(): void
+	public function doFoo(): string
 	{
+		return 'result';
 	}