Fix directives in empty class bodies

lib/yard/parser/ruby/ruby_parser.rb

@@ -658,6 +658,23 @@ def insert_comments
             end
           end unless @comments.empty?
 
+          # Attach comments that fall within an otherwise empty
+          # class or module body. Without this step, a comment used
+          # solely for directives (like @!method) would be treated as
+          # a top-level comment and its directives would not be scoped
+          # to the namespace.
+          unless @comments.empty?
+            root.traverse do |node|
+              next unless [:class, :module, :sclass].include?(node.type)
+              body = node.children.last
+              next unless body && body.type == :list && body.empty?
+              @comments.keys.each do |line|
+                next unless node.line_range.include?(line)
+                add_comment(line, nil, body, true)
+              end
+            end
+          end
+
           # insert all remaining comments
           @comments.each do |line, _comment|
             add_comment(line, nil, root, true)

spec/tags/directives_spec.rb

@@ -263,6 +263,16 @@ class Foo
       expect(Registry.at('#foo').parameters).to eq [['a', nil], ['b', nil], ['c', 'nil']]
     end
 
+    it "processes @!method inside an empty class" do
+      YARD.parse_string <<-eof
+        class Foo
+          # @!method bar
+          #   Docstring
+        end
+      eof
+      expect(Registry.at('Foo#bar').docstring).to eq 'Docstring'
+    end
+
     it "is able to define method with module scope (module function)" do
       YARD.parse_string <<-eof
         # @!method foo