return.tooWideBool

Code example

<?php declare(strict_types = 1);

/** @return bool */
function alwaysTrue(): bool
{
	if (rand(0, 1)) {
		return true;
	}

	return true;
}

Why is it reported?

The function or method declares bool as its return type, but PHPStan has determined that only one of the two boolean values (true or false) is ever actually returned. The return type is wider than necessary because one of the boolean values is never returned.

In the example above, every code path returns true, so the return type should be narrowed from bool to true.

How to fix it

Narrow the return type to the specific boolean literal type that is actually returned (PHP 8.2+):

-function alwaysTrue(): bool
+function alwaysTrue(): true
 {
 	if (rand(0, 1)) {
 		return true;
 	}

 	return true;
 }

On older PHP versions, the true standalone type is not available natively. Use a PHPDoc @return tag instead:

-/** @return bool */
+/** @return true */
 function alwaysTrue(): bool

Learn more: PHPDoc Types

If the function is a non-private method that overrides a parent method, the return type may need to stay as bool for compatibility. In that case, configure PHPStan to check protected and public methods using the checkTooWideReturnTypesInProtectedAndPublicMethods option.