InvalidDocblockType

A type in a docblock is invalid, malformed, or cannot be resolved to a known class or built-in type.

Example

<?php
/**
 * @param InvalidType $value
 */
function process($value): void {
    // InvalidType does not exist
}

How to fix

Use valid types that exist or are properly imported:

<?php
use DateTime;

/**
 * @param DateTime|string $value
 */
function process($value): void {
    // Valid types
}