[perl #123465] [BUG] /+/ is invalid as a literal regex, but causes an infinite loop when passed in as an indirect subrule call in Rakudo

[Carl Mäsak]

# New Ticket Created by  "Carl Mäsak" 
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<masak> heh, I think I found a bug in the regex engine :)
<masak> m: /+/; say "alive"
<camelia> rakudo-moar fb9127: OUTPUT«===SORRY!=== Error while
compiling /tmp/MtEpSUUPer␤Quantifier quantifies nothing [...]
<masak> m: my $rx = "+"; "" ~~ /<$rx>/; say "alive"
<camelia> rakudo-moar fb9127: OUTPUT«Memory allocation failed; could
not allocate 929136640 bytes␤»
* masak submits rakudobug
<masak> my assumption here is the /+/ is still a syntax error, even if
it happens through an injected regex.

S05 says "If the compilation of the string form fails, the error
message is converted
to a warning and the assertion fails."

So, it shouldn't die, just fail the match. It definitely shouldn't
loop forever and run out of memory.