[Fix #11844] Fix a false positive for Style/RedundantLineContinuation

Fixes #11844.

This PR fixes a false positive for `Style/RedundantLineContinuation` when
using line concatenation for assigning a return value and without argument parentheses.

changelog/fix_a_false_positive_for_style_redundant_line_continuation.md

@@ -0,0 +1 @@
+* [#11844](https://github.com/rubocop/rubocop/issues/11844): Fix a false positive for `Style/RedundantLineContinuation` when using line concatenation for assigning a return value and without argument parentheses. ([@koic][])

lib/rubocop/cop/style/redundant_line_continuation.rb

@@ -70,6 +70,10 @@ class RedundantLineContinuation < Base
 
         MSG = 'Redundant line continuation.'
         ALLOWED_STRING_TOKENS = %i[tSTRING tSTRING_CONTENT].freeze
+        ARGUMENT_TYPES = %i[
+          kFALSE kNIL kSELF kTRUE tCONSTANT tCVAR tFLOAT tGVAR tIDENTIFIER tINTEGER tIVAR
+          tLBRACK tLCURLY tLPAREN_ARG tSTRING tSTRING_BEG tSYMBOL tXSTRING_BEG
+        ].freeze
 
         def on_new_investigation
           return unless processed_source.ast
@@ -124,7 +128,7 @@ def inside_string_literal?(range, token)
         #   do_something \
         #     argument
         def method_with_argument?(current_token, next_token)
-          current_token.type == :tIDENTIFIER && next_token.type == :tIDENTIFIER
+          current_token.type == :tIDENTIFIER && ARGUMENT_TYPES.include?(next_token.type)
         end
 
         def argument_newline?(node)

spec/rubocop/cop/style/redundant_line_continuation_spec.rb

@@ -191,13 +191,141 @@ def self.foo(bar,#{trailing_whitespace}
     RUBY
   end
 
-  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses' do
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of method call' do
     expect_no_offenses(<<~'RUBY')
       foo = do_something \
         argument
     RUBY
   end
 
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of local variable' do
+    expect_no_offenses(<<~'RUBY')
+      argument = 42
+
+      foo = do_something \
+        argument
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of instance variable' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        @argument
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of class variable' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        @@argument
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of global variable' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        $argument
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of constant' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        ARGUMENT
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of string literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        'argument'
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of interpolated string literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        "argument#{x}"
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of xstring literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        `argument`
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of symbol literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        :argument
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of regexp literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        (1..9)
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of integer literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        42
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of float literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        42.0
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of true literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        true
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of false literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        false
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of nil literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        nil
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of self' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        self
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of array literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        []
+    RUBY
+  end
+
+  it 'does not register an offense when using line concatenation for assigning a return value and without argument parentheses of hash literal' do
+    expect_no_offenses(<<~'RUBY')
+      foo = do_something \
+        {}
+    RUBY
+  end
+
   it 'does not register an offense when line continuations with arithmetic operator' do
     expect_no_offenses(<<~'RUBY')
       1 \