From @masak

<masak> rakudo​: subset Greeting of Str where { /​:i ^oh \s+ \w+ '!'?$/
}; subset LolGreeting of Str where { .words[1].lc eq 'hai' }; multi
detect(Str) { "not a greeting" }; multi detect(Greeting) { "regular
greeting" }; multi detect(LolGreeting) { "lol-greeting" }; say detect
"OH HAI"
<p6eval> rakudo e9e7fc​: OUTPUT«Null PMC access in isa_pmc() [....]
* masak submits rakudobug
<ash_> rakudo​: say 'foo' ~~ /​:i foo/;
<p6eval> rakudo e9e7fc​: OUTPUT«foo␤»
<masak> ash_​: it's to do with multies, and subtypes.
<ash_> got ya
<masak> rakudo​: subset G of Str where { /O/ }; sub detect(G) {}; detect "O"
<p6eval> rakudo e9e7fc​: OUTPUT«Method 'match' not found for invocant
of class ' [...]
<masak> rakudo​: subset G of Str where { /O/ }; multi detect(G) {}; detect "O"
<p6eval> rakudo e9e7fc​: OUTPUT«Null PMC access in isa_pmc()␤ in
'&infix​:<=>' at line 1␤ in 'Regex​::Bool' at line 5970​:CORE.setting␤
in 'detect' [...]
<masak> rakudo​: subset G of Str where { .chars > 0 }; multi detect(G)
{}; detect "O"; say "alive"
<p6eval> rakudo e9e7fc​: OUTPUT«alive␤»

From @masak

<tylercurtis> rakudo​: multi detect(Str $foo where { /O/ }) {}; detect "O"
<p6eval> rakudo 377615​: OUTPUT«Null PMC access in isa_pmc() [...]
<tylercurtis> rakudo​: multi detect(Str $foo where /O/) {say 'hi'}; detect "O"
<p6eval> rakudo 377615​: OUTPUT«hi␤»
* masak adds this to the ticket
<masak> tylercurtis++
<masak> rakudo​: subset G of Str where /O/; multi detect(G) {}; detect "O"; say "alive"
<p6eval> rakudo 377615​: OUTPUT«alive␤»
<tylercurtis> rakudo​: multi detect(Str $foo where { m/O/ } ) {say 'hi'}; detect "O"
<p6eval> rakudo 377615​: OUTPUT«hi␤»
<masak> another clue. nice!

@masak - Status changed from 'new' to 'open'

From @masak

<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'

From @diakopter

The original code works now

12​:09 <diakopter> m​: subset Greeting of Str where { /​:i ^oh \s+ \w+ '!'?$/ };
  subset LolGreeting of Str where { .words[1].lc eq 'hai' };
  multi detect(Str) { "not a greeting" }; multi
  detect(Greeting) { "regular greeting" }; multi
  detect(LolGreeting) { "lol-greeting" }; say detect "OH HAI"
12​:09 <camelia> rakudo-moar 61d231​: OUTPUT«lol-greeting␤»