[Fix rubocop#4781] Prevent Style/UnneededPercentQ from breaking on …

…strings that is concated with backslash

`Style/UnneededPercentQ` raises an error when it is auto-correcting the following code.

```ruby
puts %q(foo bar baz) \
  'boogers'
```

This change will fix this problem.

CHANGELOG.md

@@ -27,6 +27,7 @@
 * [#4885](https://github.com/bbatsov/rubocop/issues/4885): Fix false offense detected by `Style/MixinUsage` cop. ([@koic][])
 * [#3363](https://github.com/bbatsov/rubocop/pull/3363): Fix `Style/EmptyElse` autocorrection removes comments from branches. ([@dpostorivo][])
 * [#5025](https://github.com/bbatsov/rubocop/issues/5025): Fix error with Layout/MultilineMethodCallIndentation cop and lambda.(...). ([@dpostorivo][])
+* [#4781](https://github.com/bbatsov/rubocop/issues/4781): Prevent `Style/UnneededPercentQ` from breaking on strings that are concated with backslash. ([@pocke][])
 
 ### Changes
 

lib/rubocop/cop/style/unneeded_percent_q.rb

@@ -18,6 +18,7 @@ class UnneededPercentQ < Cop
         ESCAPED_NON_BACKSLASH = /\\[^\\]/
 
         def on_dstr(node)
+          return unless string_literal?(node)
           check(node)
         end
 

spec/rubocop/cop/style/unneeded_percent_q_spec.rb

@@ -65,6 +65,17 @@
 
         expect(new_source).to eq("'hi'")
       end
+
+      it 'auto-corrects for strings that is concated with backslash' do
+        new_source = autocorrect_source(<<-RUBY.strip_indent)
+          %q(foo bar baz) \
+            'boogers'
+        RUBY
+        expect(new_source).to eq(<<-RUBY.strip_indent)
+          'foo bar baz' \
+            'boogers'
+        RUBY
+      end
     end
   end
 
@@ -128,6 +139,17 @@
 
         expect(new_source).to eq(%("hi\#{4}"))
       end
+
+      it 'auto-corrects for strings that is concated with backslash' do
+        new_source = autocorrect_source(<<-RUBY.strip_indent)
+          %Q(foo bar baz) \
+            'boogers'
+        RUBY
+        expect(new_source).to eq(<<-RUBY.strip_indent)
+          "foo bar baz" \
+            'boogers'
+        RUBY
+      end
     end
   end