__Native("ActRec") attribute appears to wrongly stick to following methods

Observed on HHVM 3.15.3.

In a syslib class of a form:

class C {
<<__Native("ActRec")>>
public function __construct(mixed $x);

<<__Native>>
public function test(mixed $a, mixed $b);
}

method "C->test", when implemented with non-ActRec native prototype receives junk parameters, as if "ActRec" attribute just fell through from the constructor definition above.