InvalidStringClass

A string variable is used as a class name (e.g., via new $className or $className::method()) but mir cannot determine that it resolves to a known class. This usually occurs when a plain string type (not a class-string) is used in a dynamic class instantiation.

Example

<?php
function make(string $className): object {
    return new $className(); // $className is a plain string, not a known class
}

How to fix

Narrow the type to a class-string or class-string<T> annotation so mir knows the string represents a valid class name:

<?php
/**
 * @param class-string $className
 */
function make(string $className): object {
    return new $className();
}