missing use statements should trigger an error

[schmunk42]

What steps will reproduce the problem?

Use a config with missing namespaces

<?php
return [
    ServerRequestFactoryInterface::class => Psr17Factory::class,
];

What is the expected result?

An error.

What do you get instead?

Value parsed as...

'ServerRequestFactoryInterface' => 'Nyholm\\Psr7\\Factory\\Psr17Factory',

Additional info

Q	A
Version	dev-master 7fa31d1
Composer Version	1.9.1 2019-11-01 17:20:17
PHP version	PHP 7.4.0
Operating system	Debian

[rob006]

ServerRequestFactoryInterface::class evaluates to 'ServerRequestFactoryInterface' string (this is how PHP parser works). How config plugin could detect whether provided string is correct or not?

[schmunk42]

How config plugin could detect whether provided string is correct or not?

Thinking loud, untested: class_exists($name)

[hiqsol]

<?php
return [
    ServerRequestFactoryInterface::class => Psr17Factory::class,
];

IMHO this cannot be parsed as:

    'ServerRequestFactoryInterface' => 'Nyholm\\Psr7\\Factory\\Psr17Factory',

Namespace Nyholm\Psr7\Factory is just nowhere to come from.

As to the main question about triggering an error, it is a known issue described in the README:

This plugin treats configs as simple PHP arrays. No specific structure or semantics are expected and handled. It is simple and straightforward, but I'm in doubt... What about errors and typos? I think about adding config validation rules provided together with plugins. Will it solve all the problems?

So, validators can be added. But specific validators should not be a part of the plugin.
I mean expecting class name in certain places in the configuration array is specific for Yii and those places are different for Yii 2 and 3 versions. And validation can go further than checking class names only.
The plugin could provide something like schema validation and packages could provide their schemas.