$_ no longer works in macros, rules and headers since 2.0
2feb4a40 introduced a regression
$_
is no longer correctly interpreted in macros
Try this one as an example :
join ',', map { "test_".$_ } split ',',"a,b,c"
Expected result:
test_a,test_b,test_c
Actual result:
test_,test_,test_
because LLNG looks for a _
key in session