here yet another approach to automatically introspect your source by using debugger flags - see $PERLDB:

(Crossposted at Reddit while PM was down)

BEGIN { $^P |= 0x400;};
use v5.12; 
use warnings;
use Data::Dump;

say "some code";

*DB::dbline = $::{ "_<" . __FILE__ };
ddx @DB::dbline;
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OUTPUT:

perl /home/lanx/perl/pm/source_introspection.pl 
some code
# source_introspection.pl:9: (
#   undef,
#   undef,
#   "use v5.12; \n",
#   "use warnings;\n",
#   "use Data::Dump;\n",
#   "\n",
#   "say \"some code\";\n",
#   "\n",
#   "*DB::dbline = \$::{ \"_<\" . __FILE__ };\n",
#   "ddx \@DB::dbline;\n",
# )
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