`Type\converted()` leads to insufficient type inference on shape types

[Ocramius]

When using Psl\Type\converted(), PHPStan fails to infer the type of produced shapes:

/**
 * @return \Psl\Type\TypeInterface<array{foo: non-empty-string}>
 */
function test() {
    return \Psl\Type\converted(
        \Psl\Type\shape([
            'foo' => \Psl\Type\int(),
        ]),
        \Psl\Type\shape([
            'foo' => \Psl\Type\non_empty_string(),
        ]),
        static function (array $in): array {
            return [
                'foo' => (string) $in['foo']
            ];
        }
    );
}

This could well be a PHPStan limitation, given that Psl\Type\Converted has the output type bound to both the target type and the closure, and PHPStan does not parse any /** @return ... */ declarations on closures.

/cc @ondrejmirtes this is probably related to PHPStan not parsing docblocks on closures