I think this way of declaring contents of an array is reflecting the way PHPStan any other static analysis tools and IDEs offer it, but if that's the feature to be implemented, then it should also allow for the full variant of array<keytype, valuetype> - and it should obviously allow for a bit of spicy mixture of types if this sounds reasonable, i.e. array<int, string|null> or array<string, array<int, Type>> (at least the last option may not be relevant, but union types). See https://phpstan.org/writing-php-code/phpdocs-basics#combining-phpdoc-types-with-native-typehints