[perl #122600] [BUG] Concatenating string and buf8 infiniloops

[via RT]

# New Ticket Created by  Tadeusz Sośnierz 
# Please include the string:  [perl #122600]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=122600 >


Tested on Rakudo 2014.08.

    tadzik | r: my $a = buf8.new([]); say "Foo: $a" # this is amusing
  +camelia | rakudo-jvm c793d8: OUTPUT«java.lang.StackOverflowError␤␤»
  +camelia | ..rakudo-parrot c793d8: OUTPUT«maximum recursion depth 
exceeded␤current
           | instr.: 'print_exception' pc 142392 
(src/gen/p-CORE.setting.pir:61408)
           | (gen/parrot/CORE.setting:11718)␤called from Sub 'Stringy' 
pc 233104
           | (src/gen/p-CORE.setting.pir:96775) 
(gen/parrot/CORE.setting:1038)␤ca…»
  +camelia | ..rakudo-moar c793d8: OUTPUT«(signal )»
     masak | o.O
     masak | tadzik: please submit that.
    tadzik | I think concat is the problem
    tadzik | r: my $a = buf8.new([]); say $a
  +camelia | rakudo-{parrot,jvm,moar} c793d8: OUTPUT«Buf:0x<>␤»
    tadzik | r: my $a = buf8.new([]); say "" ~ $a
    tadzik | . o O ( BOOM )
  +camelia | rakudo-jvm c793d8: OUTPUT«java.lang.RuntimeException:
           | java.lang.StackOverflowError␤␤»
  +camelia | ..rakudo-parrot c793d8: OUTPUT«maximum recursion depth 
exceeded␤current
           | instr.: 'print_exception' pc 142392 
(src/gen/p-CORE.setting.pir:61408)
           | (gen/parrot/CORE.setting:11718)␤called from Sub 'Stringy' 
pc 233104
           | (src/gen/p-CORE.setting.pir:96775) 
(gen/parrot/CORE.setting:1038)␤ca…»
  +camelia | ..rakudo-moar c793d8: OUTPUT«(signal )»
    tadzik | r: my $a = buf8.new([]); say ~$a
  +camelia | rakudo-{parrot,jvm,moar} c793d8: OUTPUT«Buf:0x<>␤»
     masak | some dispatch somewhere self-calls and goes into an 
infinite loop.
    tadzik | it would seem so, yes