From zefram@fysh.org

try { my Int $a; $a = "foo" }; say ?$!.backtrace; say ?$!.perl.EVAL.backtrace
True
False

.perl.EVAL is failing to round-trip the exception object, as demonstrated
by the differing truthiness of the value returned by .backtrace.

-zefram

From @zoffixznet

On Mon, 27 Feb 2017 14​:35​:17 -0800, zefram@​fysh.org wrote​:

try { my Int $a; $a = "foo" }; say ?$!.backtrace; say
?$!.perl.EVAL.backtrace
True
False

.perl.EVAL is failing to round-trip the exception object, as
demonstrated
by the differing truthiness of the value returned by .backtrace.

-zefram

Only public attributes of an object get dumped in .perl's output, and backtrace isn't one​:

  $ perl6 -e 'class Foo { has $!foo = 42; has $.bar = 72 }.new.perl.say'
  Foo.new(bar => 72)

The RT System itself - Status changed from 'new' to 'open'

From zefram@fysh.org

Zoffix Znet via RT wrote​:

Only public attributes of an object get dumped in .perl's output,
and backtrace isn't one​:

That's a fine default, but a problem in this case. The .backtrace method
is public, so .perl.EVAL ought to be round-tripping the data that it
exposes, however that's stored.

-zefram