Fix a false positive for Style/RedundantParentheses

changelog/fix_a_false_positive_for_style_redundant_parentheses.md

@@ -0,0 +1 @@
+* [#12505](https://github.com/rubocop/rubocop/pull/12505): Fix a false positive for `Style/RedundantParentheses` when using parenthesized `lambda` or `proc` with `do`...`end` block. ([@koic][])

lib/rubocop/cop/style/redundant_parentheses.rb

@@ -144,7 +144,9 @@ def find_offense_message(begin_node, node)
           return 'a literal' if disallowed_literal?(begin_node, node)
           return 'a variable' if node.variable?
           return 'a constant' if node.const_type?
-          return 'an expression' if node.lambda_or_proc?
+          if node.lambda_or_proc? && (node.braces? || node.send_node.lambda_literal?)
+            return 'an expression'
+          end
           return 'an interpolated expression' if interpolation?(begin_node)
 
           return if begin_node.chained?

spec/rubocop/cop/style/redundant_parentheses_spec.rb

@@ -405,6 +405,37 @@
     RUBY
   end
 
+  it 'registers an offense for parens around `->` with `do`...`end` block' do
+    expect_offense(<<~RUBY)
+      scope :my_scope, (-> do
+                       ^^^^^^ Don't use parentheses around an expression.
+        where(column: :value)
+      end)
+    RUBY
+
+    expect_correction(<<~RUBY)
+      scope :my_scope, -> do
+        where(column: :value)
+      end
+    RUBY
+  end
+
+  it 'does not register an offense for parens around `lambda` with `do`...`end` block' do
+    expect_no_offenses(<<~RUBY)
+      scope :my_scope, (lambda do
+        where(column: :value)
+      end)
+    RUBY
+  end
+
+  it 'does not register an offense for parens around `proc` with `do`...`end` block' do
+    expect_no_offenses(<<~RUBY)
+      scope :my_scope, (proc do
+        where(column: :value)
+      end)
+    RUBY
+  end
+
   it_behaves_like 'plausible', '(-2)**2'
   it_behaves_like 'plausible', '(-2.1)**2'