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Error Identifier: parameter.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 $param): void // ERROR: Parameter $param has typehint with void.
{
}

Why is it reported? #

The void type cannot be used as a parameter type in PHP. The void type is only valid as a return type, where it indicates that the function does not return a value. Using void as a parameter type is a language-level error that will cause a fatal error at runtime.

How to fix it #

Use the appropriate type for the parameter. If the parameter is intended to accept no meaningful value, consider whether the parameter is needed at all:

 <?php declare(strict_types = 1);
 
-function doFoo(void $param): void
+function doFoo(): void
 {
 }

If the parameter should accept any type including null, use mixed:

 <?php declare(strict_types = 1);
 
-function doFoo(void $param): void
+function doFoo(mixed $param): void
 {
 }

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\Functions\ExistingClassesInArrowFunctionTypehintsRule [1] [2]
  • PHPStan\Rules\Functions\ExistingClassesInClosureTypehintsRule [1] [2]
  • PHPStan\Rules\Functions\ExistingClassesInTypehintsRule [1] [2]
  • PHPStan\Rules\Methods\ExistingClassesInTypehintsRule [1] [2]
  • PHPStan\Rules\Properties\ExistingClassesInPropertyHookTypehintsRule [1] [2]

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