Error Identifier: function.resultUnused
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(string $url): void
{
sprintf('%s/path', $url);
}
Why is it reported? #
The function is called on its own line as a statement, but it has no side effects – it only computes and returns a value. Since the return value is not assigned to a variable, passed as an argument, or otherwise used, the call achieves nothing. This usually indicates that the developer forgot to use the return value or intended to call a different function.
Common examples include sprintf() (which returns a string but does not output anything, unlike printf()) and other pure functions whose results are discarded.
How to fix it #
Use the return value:
- sprintf('%s/path', $url);
+ $result = sprintf('%s/path', $url);
Or call the function that produces the intended side effect:
- sprintf('%s/path', $url);
+ printf('%s/path', $url);
How to ignore this error #
You can use the identifier function.resultUnused to ignore this error using a comment:
// @phpstan-ignore function.resultUnused
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.resultUnused