Merge pull request #6613 from reitermarkus/match-nil

Fix `#match?` on `nil`.

Library/Homebrew/rubocops/cask/homepage_url_trailing_slash.rb

@@ -15,9 +15,15 @@ module RuboCop
 
         def on_homepage_stanza(stanza)
           url_node = stanza.stanza_node.first_argument
-          url = url_node.str_content
 
-          return unless url.match?(%r{^.+://[^/]+$})
+          url = if url_node.dstr_type?
+            # Remove quotes from interpolated string.
+            url_node.source[1..-2]
+          else
+            url_node.str_content
+          end
+
+          return unless url&.match?(%r{^.+://[^/]+$})
 
           add_offense(url_node, location: :expression,
                                 message:  format(MSG_NO_SLASH, url: url))