Support Ruby 3 inline attribute visibility

See https://redmine.ruby-lang.org/issues/17314

lib/yard/handlers/ruby/visibility_handler.rb

@@ -13,10 +13,25 @@ class YARD::Handlers::Ruby::VisibilityHandler < YARD::Handlers::Ruby::Base
     case statement.type
     when :var_ref, :vcall
       self.visibility = ident.first.to_sym
-    when :fcall, :command
+    when :command
+      if RUBY_VERSION >= '3.' && is_attribute_method?(statement.parameters.first)
+        visibility_was = visibility
+        self.visibility = ident.first.to_sym
+        parse_block(statement.parameters.first, visibility: visibility)
+        self.visibility = visibility_was
+        return
+      end
+      process_decorator do |method|
+        method.visibility = ident.first if method.respond_to? :visibility=
+      end
+    when :fcall
       process_decorator do |method|
         method.visibility = ident.first if method.respond_to? :visibility=
       end
     end
   end
+
+  def is_attribute_method?(node)
+    node.type == :command && node.jump(:ident).first.to_s =~ /^attr_(accessor|writer|reader)$/
+  end
 end

spec/handlers/examples/visibility_handler_002.rb.txt

@@ -0,0 +1,7 @@
+class Testing
+  private attr_accessor :inline_private_attr
+  protected attr_writer :inline_protected_writer
+
+  # This one should be public
+  attr_reader :inline_public_reader
+end

spec/handlers/visibility_handler_spec.rb

@@ -41,4 +41,15 @@
   it "can decorate a method definition" do
     expect(Registry.at('Testing#decpriv').visibility).to eq :private
   end unless LEGACY_PARSER
+
+  describe 'ruby 3 specific features' do
+    before(:all) { parse_file :visibility_handler_002, __FILE__ }
+
+    it "handles attr_accessor when inlined" do
+      expect(Registry.at('Testing#inline_private_attr').visibility).to eq :private
+      expect(Registry.at('Testing#inline_private_attr=').visibility).to eq :private
+      expect(Registry.at('Testing#inline_protected_writer=').visibility).to eq :protected
+      expect(Registry.at('Testing#inline_public_reader').visibility).to eq :public
+    end
+  end if RUBY_VERSION >= "3."
 end