you can get an instance of a class through dependency injection in Yii2 in this way
$test = \Yii::$container->get("\common\service\test");
$test->aa(); clicking aa () will not jump to the corresponding function, and typing $test- > will not list the methods under the test class
there is no code hint in the following way of writing, and clicking aa () will not jump
$testClass = "\common\service\test";
$test = new $testClass;
$test->aa();