[Fix rubocop#13319] Handle literal forward slashes inside a regexp …

…in `Lint/LiteralInInterpolation`.

changelog/fix_handle_literal_forward_slashes_inside_a_regexp_in.md

@@ -0,0 +1 @@
+* [#13319](https://github.com/rubocop/rubocop/issues/13319): Handle literal forward slashes inside a `regexp` in `Lint/LiteralInInterpolation`. ([@dvandersluis][])

lib/rubocop/cop/lint/literal_in_interpolation.rb

@@ -30,6 +30,11 @@ def on_interpolation(begin_node)
           # interpolation should not be removed if the expanded value
           # contains a space character.
           expanded_value = autocorrected_value(final_node)
+
+          if begin_node.parent.regexp_type?
+            expanded_value = handle_special_regexp_chars(expanded_value)
+          end
+
           return if in_array_percent_literal?(begin_node) && /\s|\A\z/.match?(expanded_value)
 
           add_offense(final_node) do |corrector|
@@ -77,6 +82,12 @@ def autocorrected_value(node)
         end
         # rubocop:enable Metrics/MethodLength, Metrics/CyclomaticComplexity
 
+        def handle_special_regexp_chars(value)
+          return value unless value['/']
+
+          value.gsub!('/', '\/')
+        end
+
         def autocorrected_value_for_string(node)
           if node.source.start_with?("'", '%q')
             node.children.last.inspect[1..-2]

spec/rubocop/cop/lint/literal_in_interpolation_spec.rb

@@ -423,4 +423,43 @@
       RUBY
     end
   end
+
+  context 'handling regexp special characters' do
+    context 'when inside a `regexp` node' do
+      it 'properly escapes the autocorrection' do
+        expect_offense(<<~'RUBY')
+          /test#{'/'}test/
+                 ^^^ Literal interpolation detected.
+        RUBY
+
+        expect_correction(<<~'RUBY')
+          /test\/test/
+        RUBY
+      end
+
+      it 'handles longer strings' do
+        expect_offense(<<~'RUBY')
+          /test#{'/a/b/c/'}test/
+                 ^^^^^^^^^ Literal interpolation detected.
+        RUBY
+
+        expect_correction(<<~'RUBY')
+          /test\/a\/b\/c\/test/
+        RUBY
+      end
+    end
+
+    context 'when inside a non-`regexp` node' do
+      it 'does not escape the autocorrection' do
+        expect_offense(<<~'RUBY')
+          "test#{'/'}test"
+                 ^^^ Literal interpolation detected.
+        RUBY
+
+        expect_correction(<<~RUBY)
+          "test/test"
+        RUBY
+      end
+    end
+  end
 end