phpunit: Unable to chain a @dataProvider in method a with a @depends in method b

Q	A
PHPUnit version	7.0.2
PHP version	7.1.10
Installation Method	Composer

Here is a code snippet of what I mean in the title

/**
 * @return array
 */
public function demoDP(): array 
{
	return [[0], [1], [2], [3]];
}

/**
 * @dataProvider demoDP
 * @param int $nr
 * @return int
 */
public function testDemoA(int $nr): int
{
	self::assertTrue($nr >= 0);
	return $nr + 1;
}

/**
 * @depends testDemoA
 * @param int $nr
 */
public function testDemoB(int $nr)
{
	self::assertTrue($nr > 0);
}

I would expect testDemoA to run 4 times: with $nr equal to 0, 1, 2 and 3. I also expect testDemoB to run 4 times: with $nr equal to 1, 2, 3 and 4.

testDemoA works fine, but testDemoB gives the error `Argument 1 passed to <testclass>::testDemoB() must be of the type integer, null given

If I don’t use the dataprovider for testDemoA, but a hardcoded value for $nr instead, testDemoB works fine, so the problem lies with using @depends in one method that refers to a method that uses a dataprovider.