cpanfile

requires 'App::cpanminus' => '1.6008';
requires 'JSON'           => '2.53';
requires 'Furl'           => '2.10';
_requires 'List::Util'     => 0;

on 'configure' => sub {
    requires 'Module::Build' => '0.40';
    requires 'Module::Build' => '0.09';
};

on 'build' => sub {
    requires 'Test::More' => '0.98';
};

parse_cpanfile.pl

#!/usr/bin/env perl

use strict;
use warnings;
use utf8;
use 5.012000;

use Module::CPANfile;

my $file   = $ARGV[0];
my $parser = Module::CPANfile->load($file);
my $res    = $parser->parse();

$ perl parse_cpanfile.pl ./cpanfile

I expect the above command will output

Parsing /foo/bar/cpanfile failed: syntax error at (eval 1) line 4, near "_requires 'List::Util'"

however it outputs

Parsing /foo/bar/cpanfile failed: syntax error at (eval 1) line 9, near "_requires 'List::Util'"

It inform us that error line number that is increased 5 lines.