Add auto-correct for Style/StructInheritance

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### New features
+
+* [#8111](https://github.com/rubocop-hq/rubocop/pull/8111): Add auto-correct for `Style/StructInheritance`. ([@tejasbubane][])
+
 ## 0.85.1 (2020-06-07)
 
 ### Bug fixes

config/default.yml

@@ -3875,6 +3875,7 @@ Style/StructInheritance:
   StyleGuide: '#no-extend-struct-new'
   Enabled: true
   VersionAdded: '0.29'
+  VersionChanged: '0.86'
 
 Style/SymbolArray:
   Description: 'Use %i or %I for arrays of symbols.'

docs/modules/ROOT/pages/cops_style.adoc

@@ -8693,9 +8693,9 @@ This cop identifies places where `lstrip.rstrip` can be replaced by
 
 | Enabled
 | Yes
-| No
+| Yes
 | 0.29
-| -
+| 0.86
 |===
 
 This cop checks for inheritance from Struct.new.

lib/rubocop/cop/style/struct_inheritance.rb

@@ -20,6 +20,8 @@ module Style
       #     end
       #   end
       class StructInheritance < Cop
+        include RangeHelp
+
         MSG = "Don't extend an instance initialized by `Struct.new`. " \
               'Use a block to customize the struct.'
 
@@ -29,10 +31,29 @@ def on_class(node)
           add_offense(node, location: node.parent_class.source_range)
         end
 
+        def autocorrect(node)
+          lambda do |corrector|
+            corrector.remove(range_with_surrounding_space(range: node.loc.keyword))
+            corrector.replace(node.loc.operator, '=')
+
+            correct_parent(node.parent_class, corrector)
+          end
+        end
+
         def_node_matcher :struct_constructor?, <<~PATTERN
           {(send (const nil? :Struct) :new ...)
            (block (send (const nil? :Struct) :new ...) ...)}
         PATTERN
+
+        private
+
+        def correct_parent(parent, corrector)
+          if parent.block_type?
+            corrector.remove(range_with_surrounding_space(range: parent.loc.end, newlines: false))
+          else
+            corrector.insert_after(parent.loc.expression, ' do')
+          end
+        end
       end
     end
   end

spec/rubocop/cop/style/struct_inheritance_spec.rb

@@ -7,6 +7,13 @@
     expect_offense(<<~RUBY)
       class Person < Struct.new(:first_name, :last_name)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Struct.new`. Use a block to customize the struct.
+        def foo; end
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      Person = Struct.new(:first_name, :last_name) do
+        def foo; end
       end
     RUBY
   end
@@ -17,6 +24,11 @@ class Person < Struct.new(:first_name, :last_name) do end
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't extend an instance initialized by `Struct.new`. Use a block to customize the struct.
       end
     RUBY
+
+    expect_correction(<<~RUBY)
+      Person = Struct.new(:first_name, :last_name) do
+      end
+    RUBY
   end
 
   it 'accepts plain class' do