Need to move < /dev/null to the back

[jidanni]

< /dev/null HOME=/dev/null reportbug --template ca-certifica<TAB>

needs to have the < /dev/null moved to the back to make it work.
5.2.15(1)-release
echo "${BASH_COMPLETION_VERSINFO[*]}"
2 11

[akinomyoga]

Bash seems to call the completion function for an empty command (complete -F ... '') in this case. We need to skip the redirections and temporary environments to find the actual command name and delegate the completion generation using _comp_command_offset.