[Fix #12797] Fix false positives for Style/RedundantLineContinuation

Fixes #12797.

This PR fixes false positives for `Style/RedundantLineContinuation`
when using line continuations with `&&` or `||` operator in assignment.

changelog/fix_false_positives_for_style_redundant_line_continuation.md

@@ -0,0 +1 @@
+* [#12797](https://github.com/rubocop/rubocop/issues/12797): Fix false positives for `Style/RedundantLineContinuation` when using line continuations with `&&` or `||` operator in assignment. ([@koic][])

lib/rubocop/cop/style/redundant_line_continuation.rb

@@ -124,10 +124,10 @@ def redundant_line_continuation?(range)
           return true unless (node = find_node_for_line(range.line))
           return false if argument_newline?(node)
 
-          continuation_node = node.parent || node
+          continuation_node = node.assignment? ? node.expression : (node.parent || node)
           return false if allowed_type?(node) || allowed_type?(continuation_node)
 
-          continuation_node.source.include?("\n") || continuation_node.source.include?("\\\n")
+          continuation_node.source.match?(/(\n|\\\n")/)
         end
 
         def inside_string_literal?(range, token)

spec/rubocop/cop/style/redundant_line_continuation_spec.rb

@@ -484,6 +484,20 @@ def self.foo(bar,#{trailing_whitespace}
     RUBY
   end
 
+  it 'does not register an offense when line continuations with `&&` in assignments' do
+    expect_no_offenses(<<~'RUBY')
+      foo = bar\
+        && baz
+    RUBY
+  end
+
+  it 'does not register an offense when line continuations with `||` in assignments' do
+    expect_no_offenses(<<~'RUBY')
+      foo = bar\
+        || baz
+    RUBY
+  end
+
   it 'does not register an offense when line continuations with `&&` in method definition' do
     expect_no_offenses(<<~'RUBY')
       def do_something