plus.rightNonNumeric

Code example

<?php declare(strict_types = 1);

function add(int $a, bool $flag): int
{
	return $a + $flag;
}

Why is it reported?

The + operator in PHP performs arithmetic addition on numeric types or array union on arrays. Using a non-numeric, non-array type on the right side of + is a type error that leads to unexpected behaviour or a runtime fatal error.

This rule is part of phpstan-strict-rules.

How to fix it

Ensure the right operand is a numeric type:

-function add(int $a, bool $flag): int
+function add(int $a, int $b): int
 {
-	return $a + $flag;
+	return $a + $b;
 }

Or cast the value explicitly:

 function add(int $a, bool $flag): int
 {
-	return $a + $flag;
+	return $a + (int) $flag;
 }