Error Identifier: postDec.expr

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);

date('j. n. Y')--;

Why is it reported? #

The post-decrement operator (--) can only be applied to variables, properties, array offsets, or static properties. Applying it to a non-variable expression such as a function call result is not valid because PHP cannot assign the decremented value back to anything.

In the example above, date('j. n. Y') returns a temporary string value that has no storage location, so the -- operator cannot decrement it.

How to fix it #

Store the value in a variable first, then apply the decrement operator to that variable:

 <?php declare(strict_types = 1);
 
-date('j. n. Y')--;
+$date = date('j. n. Y');
+$date--;

How to ignore this error #

You can use the identifier postDec.expr to ignore this error using a comment:

// @phpstan-ignore postDec.expr
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: postDec.expr

Rules that report this error #

PHPStan\Rules\Operators\InvalidIncDecOperationRule [1]

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