lib/rubocop/cop/style/method_def_parentheses.rb in rubocop-1.24.0 vs lib/rubocop/cop/style/method_def_parentheses.rb in rubocop-1.24.1

@@ -4,13 +4,18 @@
   module Cop
     module Style
       # This cop checks for parentheses around the arguments in method
       # definitions. Both instance and class/singleton methods are checked.
       #
-      # This cop does not consider endless methods, since parentheses are
-      # always required for them.
+      # Regardless of style, parentheses are necessary for:
       #
+      # 1. Endless methods
+      # 2. Argument lists containing a `forward-arg` (`...`)
+      # 3. Argument lists containing an anonymous block forwarding (`&`)
+      #
+      # Removing the parens would be a syntax error here.
+      #
       # @example EnforcedStyle: require_parentheses (default)
       #   # The `require_parentheses` style requires method definitions
       #   # to always use parentheses
       #
       #   # bad
@@ -119,25 +124,17 @@
         def correct_arguments(arg_node, corrector)
           corrector.replace(arg_node.loc.begin, ' ')
           corrector.remove(arg_node.loc.end)
         end
 
-        def correct_definition(def_node, corrector)
-          arguments_range = def_node.arguments.source_range
-          args_with_space = range_with_surrounding_space(range: arguments_range, side: :left)
-          leading_space = range_between(args_with_space.begin_pos, arguments_range.begin_pos)
-          corrector.replace(leading_space, '(')
-          corrector.insert_after(arguments_range, ')')
-        end
-
         def forced_parentheses?(node)
           # Regardless of style, parentheses are necessary for:
           # 1. Endless methods
           # 2. Argument lists containing a `forward-arg` (`...`)
+          # 3. Argument lists containing an anonymous block forwarding (`&`)
           # Removing the parens would be a syntax error here.
-
-          node.endless? || node.arguments.any?(&:forward_arg_type?)
+          node.endless? || node.arguments.any?(&:forward_arg_type?) || anonymous_block_arg?(node)
         end
 
         def require_parentheses?(args)
           style == :require_parentheses ||
             (style == :require_no_parentheses_except_multiline && args.multiline?)
@@ -149,20 +146,27 @@
 
         def missing_parentheses(node)
           location = node.arguments.source_range
 
           add_offense(location, message: MSG_MISSING) do |corrector|
-            correct_definition(node, corrector)
+            add_parentheses(node.arguments, corrector)
+
             unexpected_style_detected 'require_no_parentheses'
           end
         end
 
         def unwanted_parentheses(args)
           add_offense(args, message: MSG_PRESENT) do |corrector|
             # offense is registered on args node when parentheses are unwanted
             correct_arguments(args, corrector)
             unexpected_style_detected 'require_parentheses'
           end
+        end
+
+        def anonymous_block_arg?(node)
+          return false unless (last_argument = node.arguments.last)
+
+          last_argument.blockarg_type? && last_argument.name.nil?
         end
       end
     end
   end
 end