Description:
------------
Password component is not matched if only the authority part is given... it does matches however if a scheme is provided with it.

Due the difference between example 2 and 3 i'm not sure if a relative URI reference is supported or not.

Test script:
---------------
<?php
var_dump(parse_url('http://user:pass@host'));
var_dump(parse_url('//user:pass@host'));
var_dump(parse_url('//user@host'));

Expected result:
----------------
array(4) {
  ["scheme"]=>
  string(4) "http"
  ["host"]=>
  string(4) "host"
  ["user"]=>
  string(4) "user"
  ["pass"]=>
  string(4) "pass"
}
array(3) {
  ["host"]=>
  string(4) "host"
  ["user"]=>
  string(4) "user"
  ["pass"]=>
  string(4) "pass"
}
array(2) {
  ["host"]=>
  string(4) "host"
  ["user"]=>
  string(4) "user"
}


Actual result:
--------------
array(4) {
  ["scheme"]=>
  string(4) "http"
  ["host"]=>
  string(4) "host"
  ["user"]=>
  string(4) "user"
  ["pass"]=>
  string(4) "pass"
}
array(1) {
  ["path"]=>
  string(16) "//user:pass@host"
}
array(2) {
  ["host"]=>
  string(4) "host"
  ["user"]=>
  string(4) "user"
}