Support for old style constructors was added in 0c6d07e

However, if you add this to the bottom of the test in https://github.com/vimeo/psalm/blob/master/tests/Php40Test.php :

class C extends SoapClient {
    public function __construct() {
         parent::__construct();
    }
}

it fails with InaccessibleMethod - somefile.php:19 - Cannot access method SoapClient::__construct.

Poked around in the code a bit and it looks like since Psalm doesn't check SoapClient it doesn't know to register the constructor as __construct.