Note that it works if you add a label, as in:
### Expected: $self->{slot}
A patch seems to be replacing line 135
134: # Dump an unlabelled expression
135:
{Smart::Comments::_Dump(pref=>q{$1:},var=>Smart::Comments::_quiet_eval(q{[$1]}));$DBX}gmx;
with the following one :
135: {Smart::Comments::_Dump(pref=>q{$1:},var=>[$1]);$DBX}gmx;
which I copied from :
126: # Dump a labelled expression...
127: s{ ^ $hws* $intro [ \t]+ (.+ :) (.+) }
128: {Smart::Comments::_Dump(pref=>q{$1},var=>[$2]);$DBX}gmx;
It does pass all the tests. However, I am not sure that it has no weird
side effect: the author might have had a reason to call _quiet_eval when
the expression is not labelled.