[perl #129212] problem mixing in role with multi builds

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Hi,

I get the following error using version 2016.08.1-66-g1ff1aae built on 
MoarVM version 2016.08
implementing Perl 6.c.

Cannot resolve caller BUILD(CC+{RR}: ); none of these signatures match:
      (CC $: Str :$t!, *%_)
      (CC $: Int :$i!, *%_)
    in block <unit> at Build2.pl6 line 15



The code which generates the error (on the line with '$c does RR');


role RR { }

class CC {

    multi submethod BUILD ( Str :$t! ) { }
    multi submethod BUILD ( Int :$i! ) { }
}

my CC $c .= new(:t<text1>);
$c does RR;


Removing the last line and add a trait 'does' to the class works but is 
not what I want.

Greetings,
Marcel


P.s. I've sent this mail before to rakudobug but I did not see it appear 
in the list. Sorry for duplication if it did appear somewhere else.