From 978578a677d5a9aa6dec439e301d7bc563a4de0e Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Tue, 23 Mar 2021 01:31:11 +0900
Subject: [PATCH] Fix an incorrect auto-correct for `Style/RedundantReturn`

Fixes https://github.com/testdouble/standard/issues/277.

This PR fixes the following false positive for `Style/RedundantReturn`
when using `return` with splat argument.

```console
% cat example.rb
class MyClass
  def something
    data = [1, 2, 3]
    return *data
  end
end
```

## Before

Auto-corrected to invalid code.

```console
% rubocop --only Style/RedundantReturn -a
(snip)

% cat example.rb
class MyClass
  def something
    data = [1, 2, 3]
    *data
  end
end

% ruby -c example.rb
example.rb:4: syntax error, unexpected '\n', expecting '='
```

## After

Auto-corrected to valid code.

```console
% rubocop --only Style/RedundantReturn -a
(snip)

% cat example.rb
class MyClass
  def something
    data = [1, 2, 3]
    data
  end
end

% ruby -c example.rb
Syntax OK
```
---
 ...false_positive_for_style_redundant_return.md |  1 +
 lib/rubocop/cop/style/redundant_return.rb       |  4 ++++
 spec/rubocop/cop/style/redundant_return_spec.rb | 17 +++++++++++++++++
 3 files changed, 22 insertions(+)
 create mode 100644 changelog/fix_false_positive_for_style_redundant_return.md

diff --git a/changelog/fix_false_positive_for_style_redundant_return.md b/changelog/fix_false_positive_for_style_redundant_return.md
new file mode 100644
index 00000000000..7ed400a1355
--- /dev/null
+++ b/changelog/fix_false_positive_for_style_redundant_return.md
@@ -0,0 +1 @@
+* [#9631](https://github.com/rubocop/rubocop/issues/9631): Fix an incorrect auto-correct for `Style/RedundantReturn` when using `return` with splat argument. ([@koic][])
diff --git a/lib/rubocop/cop/style/redundant_return.rb b/lib/rubocop/cop/style/redundant_return.rb
index 15e393c9945..979da17271b 100644
--- a/lib/rubocop/cop/style/redundant_return.rb
+++ b/lib/rubocop/cop/style/redundant_return.rb
@@ -71,6 +71,10 @@ def correct_with_arguments(return_node, corrector)
           elsif hash_without_braces?(return_node.first_argument)
             add_braces(corrector, return_node.first_argument)
           end
+          if return_node.splat_argument?
+            first_argument = return_node.first_argument
+            corrector.replace(first_argument, first_argument.source.gsub(/\A\*/, ''))
+          end
 
           keyword = range_with_surrounding_space(range: return_node.loc.keyword,
                                                  side: :right)
diff --git a/spec/rubocop/cop/style/redundant_return_spec.rb b/spec/rubocop/cop/style/redundant_return_spec.rb
index 7c480c62c8b..8d10aa00d93 100644
--- a/spec/rubocop/cop/style/redundant_return_spec.rb
+++ b/spec/rubocop/cop/style/redundant_return_spec.rb
@@ -54,6 +54,23 @@ def func
     RUBY
   end
 
+  it 'reports an offense for def ending with return with splat argument' do
+    expect_offense(<<~RUBY)
+      def func
+        some_preceding_statements
+        return *something
+        ^^^^^^ Redundant `return` detected.
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      def func
+        some_preceding_statements
+        something
+      end
+    RUBY
+  end
+
   it 'reports an offense for defs ending with return' do
     expect_offense(<<~RUBY)
       def self.func