[Fix rubocop#12402] Fix false negatives for `Style/RedundantLineConti…

…nuation`

Fixes rubocop#12402.

This PR fixes false negatives for `Style/RedundantLineContinuation`
when redundant line continuations for a block are used,
especially without parentheses around first argument.

changelog/fix_false_negatives_for_style_redundant_line_continuation.md

@@ -0,0 +1 @@
+* [#12402](https://github.com/rubocop/rubocop/issues/12402): Fix false negatives for `Style/RedundantLineContinuation` when redundant line continuations for a block are used, especially without parentheses around first argument. ([@koic][])

lib/rubocop/cop/style/redundant_line_continuation.rb

@@ -107,6 +107,8 @@ def string_concatenation?(source_line)
 
         def inside_string_literal_or_method_with_argument?(range)
           processed_source.tokens.each_cons(2).any? do |token, next_token|
+            next if token.line == next_token.line
+
             inside_string_literal?(range, token) || method_with_argument?(token, next_token)
           end
         end

spec/rubocop/cop/style/redundant_line_continuation_spec.rb

@@ -59,6 +59,25 @@ def self.foo(bar,#{trailing_whitespace}
     RUBY
   end
 
+  it 'registers an offense when redundant line continuations for a block are used, ' \
+     'especially without parentheses around first argument' do
+    expect_offense(<<~'RUBY')
+      let :foo do \
+                  ^ Redundant line continuation.
+        foo(bar, \
+                 ^ Redundant line continuation.
+            baz)
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      let :foo do#{' '}
+        foo(bar,#{' '}
+            baz)
+      end
+    RUBY
+  end
+
   it 'registers an offense when redundant line continuations for method chain' do
     expect_offense(<<~'RUBY')
       foo. \