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Error Identifier: function.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 doSomething(): void
{
    echo 'done';
}

$result = doSomething();

Why is it reported? #

The return value of a function that returns void is being used. A void return type means the function does not return a meaningful value. Using the result of such a function call is a mistake because the value will always be null, and the code likely contains a logic error where the wrong function is being called or the return value is being mistakenly assigned.

How to fix it #

If the function should return a value, change its return type:

 <?php declare(strict_types = 1);
 
-function doSomething(): void
+function doSomething(): string
 {
-    echo 'done';
+    return 'done';
 }

 $result = doSomething();

If the function correctly returns void, do not use its return value:

 <?php declare(strict_types = 1);
 
 function doSomething(): void
 {
     echo 'done';
 }

-$result = doSomething();
+doSomething();

How to ignore this error #

You can use the identifier function.void to ignore this error using a comment:

// @phpstan-ignore function.void
codeThatProducesTheError();

You can also use only the identifier key to ignore all errors of the same type in your configuration file in the ignoreErrors parameter:

parameters:
	ignoreErrors:
		-
			identifier: function.void

Rules that report this error #

• PHPStan\Rules\Classes\ClassAttributesRule [1]
• PHPStan\Rules\Classes\ClassConstantAttributesRule [1]
• PHPStan\Rules\Classes\InstantiationRule [1]
• PHPStan\Rules\Constants\ConstantAttributesRule [1]
• PHPStan\Rules\EnumCases\EnumCaseAttributesRule [1]
• PHPStan\Rules\Functions\ArrowFunctionAttributesRule [1]
• PHPStan\Rules\Functions\CallCallablesRule [1]
• PHPStan\Rules\Functions\CallToFunctionParametersRule [1]
• PHPStan\Rules\Functions\CallUserFuncRule [1]
• PHPStan\Rules\Functions\ClosureAttributesRule [1]
• PHPStan\Rules\Functions\FunctionAttributesRule [1]
• PHPStan\Rules\Functions\ParamAttributesRule [1]
• PHPStan\Rules\Methods\CallMethodsRule [1]
• PHPStan\Rules\Methods\CallStaticMethodsRule [1]
• PHPStan\Rules\Methods\MethodAttributesRule [1]
• PHPStan\Rules\Properties\PropertyAttributesRule [1]
• PHPStan\Rules\Properties\PropertyHookAttributesRule [1]
• PHPStan\Rules\Traits\TraitAttributesRule [1]

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