Error Identifier: property.nameNotString

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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);

class Foo
{
	public string $bar = "hello";
}

function doFoo(Foo $foo): void
{
	$name = ["bar"];
	echo $foo->$name;
}

Why is it reported? #

When accessing an object property dynamically using the $obj->$name syntax, the $name expression must evaluate to a string. If the value used as the property name is not a string (for example, an array or object), the property access is invalid and will produce unexpected behavior or errors at runtime.

In the example above, the variable $name is an array (["bar"]), which is not a valid property name.

How to fix it #

Ensure the dynamic property name is a string:

 function doFoo(Foo $foo): void
 {
-	$name = ["bar"];
+	$name = "bar";
 	echo $foo->$name;
 }

Or use a direct property access if the property name is known:

 function doFoo(Foo $foo): void
 {
-	$name = ["bar"];
-	echo $foo->$name;
+	echo $foo->bar;
 }

How to ignore this error #

You can use the identifier property.nameNotString to ignore this error using a comment:

// @phpstan-ignore property.nameNotString
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: property.nameNotString

Rules that report this error #

• PHPStan\Rules\Properties\AccessPropertiesInAssignRule [1]
• PHPStan\Rules\Properties\AccessPropertiesRule [1]