new.nonObject

Code example

<?php declare(strict_types = 1);

function doFoo(int $int): void
{
	new $int;
}

Why is it reported?

The dynamic instantiation syntax new $expr requires $expr to be either a string holding a class name or an object whose class should be instantiated. When $expr is any other type — such as int, float, bool, array, or a union that includes those types — PHP throws a fatal Error at runtime:

Uncaught Error: Class name must be a valid object or a string

A nullable string (string|null) is also reported, because passing null triggers the same fatal error.

How to fix it

Make sure the expression used after new resolves to a class name or an object. Narrow the type so the non-object cases are excluded:

-function doFoo(int $int): void
+function doFoo(string $class): void
 {
-	new $int;
+	new $class;
 }

When the value can legitimately hold several types, narrow the type before instantiating:

 /** @param int|string $intOrString */
 function doFoo($intOrString): void
 {
+	if (!is_string($intOrString)) {
+		return;
+	}
 	new $intOrString;
 }

For a parameter that is meant to receive a class name, use the class-string type so PHPStan and other developers know only class names are accepted:

-/** @param string $class */
+/** @param class-string $class */
 function doFoo(string $class): void
 {
 	new $class;
 }