[perl #78276] [BUG] Null PMC access when calling a multi sub with a parameter narrowed by a subtype that does a regex match in Rakudo

[Carl Mäsak via RT]

<masak> r: sub detect(Str $foo where { /O/ }) {}; detect "O"
<p6eval> rakudo 34e8d4: OUTPUT«No such method 'match' for invocant of 
type 'Any' [...]
<jnthn> Oh...is that a sink context oopsie?
<masak> r: subset Ostring of Str where { /O/ }; say "O" ~~ Ostring
<p6eval> rakudo 34e8d4: OUTPUT«No such method 'match' for invocant of 
type 'Any' [...]
<masak> seems so.
<jnthn> Not surprising given we don't really do sink context properly 
yet.
<jnthn> A curious place for it to fall out though
* masak updates the ticket
<masak> r: say "O" ~~ { /O/ }
<p6eval> rakudo 34e8d4: OUTPUT«␤»
<moritz> I guess the problem is that at the point where the regex is 
evaluated in boolean context, $_ isn't bound to 'O'