Error Identifier: nullableType.void
Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.
Code example #
<?php declare(strict_types = 1);
function doFoo(): ?void
{
}
Why is it reported? #
The type void cannot be used in a nullable type declaration (?void). The void return type means the function does not return any value. Making it nullable is contradictory and not allowed in PHP.
How to fix it #
Use void without the nullable modifier if the function does not return a value:
<?php declare(strict_types = 1);
-function doFoo(): ?void
+function doFoo(): void
{
}
If the function may return null, use a proper return type like ?int, string|null, or mixed.
Non-ignorable error #
This error cannot be ignored using @phpstan-ignore or the ignoreErrors configuration. Non-ignorable errors indicate code that would cause a crash or a fatal error at runtime, or a fundamental problem in the analysed code that must be addressed.
Rules that report this error #
- PHPStan\Rules\Types\InvalidTypesInUnionRule [1]