SplFixedArray uses T|null in return types because value can be null if an offset is unset or if the size does not match the number of elements. (https://github.com/phpstan/phpstan-src/blob/c5d7128a8183efd61e73558626faf549e52db65a/stubs/ArrayObject.stub#L91-L93)

But our Tokens class takes care of it and always ensures correct size and indexes, so that these methods never return null instead of Token.

So I suggest to override these return types.

At the moment it resolves only some ignored errors. But in higher PHPStan level it would resolve 342 new errors.