Invalid rule, couldn't parse '//*[@name="date", node => $mech->current
+_form ]'
[download]

This looks as if you're mixing Perl code and an XPath expression in the same string.

 my @date_fields =$mech->selector( './/*[@name="date"]', node => $mech
+->current_form );
# stderr: Invalid rule, couldn't parse '//*[@name="date"]' at /usr/loc
+al/share/perl/5.26.1/HTML/Selector/XPath.pm line 283.
[download]

This is weird - I think this should still parse as an XPath expression. Does the following work and give the expected result?

 my @date_fields =$mech->xpath( './/*[@name="date"]', node => $mech->c
+urrent_form );
[download]

With version 0.48 of WWW::Mechanize::Chrome, ->set_fields now also supports selecing input elements by their name and index:

$mech->set_fields(
    date => [3, $date_value],
);
[download]