Redmine

Observed Behavior
Create new issue with description "<a href="*tel:*3453454353">234234</a>" (href to tel with or without slashes)

ActionView::Template::Error (undefined method `+' for nil:NilClass):
2:
3: <%= render_email_issue_attributes(issue, users.first, true) >
4:
5: <= textilizable(issue, :description, :only_path => false) >
6:
7: < if issue.attachments.any? >
8: <fieldset class="attachments"><legend><= l(:label_attachment_plural) %></legend>
app/helpers/application_helper.rb:873:in `block in parse_redmine_links'
app/helpers/application_helper.rb:742:in `gsub!'
app/helpers/application_helper.rb:742:in `parse_redmine_links'
app/helpers/application_helper.rb:584:in `block (2 levels) in textilizable'
app/helpers/application_helper.rb:583:in `each'
app/helpers/application_helper.rb:583:in `block in textilizable'
app/helpers/application_helper.rb:604:in `parse_non_pre_blocks'
app/helpers/application_helper.rb:582:in `textilizable'

Redmine 3.1.

I try to replace function parse_redmine_links in file application_helper.rb from last in GIT (it's changes after issue #19304), but it's not help.