[perl #126728] Match using the wrong class

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# New Ticket Created by  mt1957 
# Please include the string:  [perl #126728]
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# <URL: https://rt.perl.org/Ticket/Display.html?id=126728 >


Following code generates 'P6opaque: must compose before allocating'.

package P {
   class Regex {
     has Int $.n;
     submethod BUILD ( Str :$n ) {
       die 'Not that one!!!' if $n ~~ m/^ '666' $/;
       $!n = $n.Int;
     }
   }
}

my P::Regex $r .= new(:n<777>);
say $r.n;


This error is generated because the matching test is somehow using the 
class still to be build and
not referring to its proper Match/Regex class. Something in the 
definition of infix:<~~> perhaps.

Marcel