Style/StringLiterals: link_to '#foo' not detected as violating double_quotes

[paulkoegel]

link_to '#foo' is not detected as violating Style/StringLiterals set to double_quotes.

Sample code with comments:

link_to '#foo' # should raise a Rubocop error but doesn't :(
link_to 'jim', key: 'value' # correctly detected ^_^
link_to "bob", key: "other value" # passes, move along :)

Expected behavior

link_to '#foo' should be detected as not using double quotes

Actual behavior

it is not detected although it uses single quotes. When chaning the string to 'foo' it does get detected.
Output from sample repository:

rubocop
Inspecting 2 files
.C

Offenses:

test.rb:2:9: C: Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping.
link_to 'jim', key: 'value' # correctly detected ^_^
        ^^^^^
test.rb:2:21: C: Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping.
link_to 'jim', key: 'value' # correctly detected ^_^
                    ^^^^^^^

2 files inspected, 2 offenses detected

Steps to reproduce the problem

Please see sample repository: https://github.com/paulkogel/rubocop-bug
bundle install and run rubocop

RuboCop version

0.39.0

$ rubocop -V
0.39.0 (using Parser 2.3.0.7, running on ruby 2.3.0 x86_64-darwin15)

[deivid-rodriguez]

Dupe of #3017, I think.

[jonas054]

Not exactly. We'll keep both issues open, because # is a 7-bit ASCII character, so it's a different bug than the failure to report strings with, for example, ñ in them.