Error while using optional on Dry::Struct about dry-struct HOT 4 CLOSED

class TestStruct < Dry::Struct
  attribute :foo, T::Strict::String
  attribute? :bar, T::Strict::String
end

diff --git a/spec/integration/struct_spec.rb b/spec/integration/struct_spec.rb
index 889637e..d88d8ae 100644
--- a/spec/integration/struct_spec.rb
+++ b/spec/integration/struct_spec.rb
@@ -205,6 +205,22 @@ RSpec.describe Dry::Struct do
     end
   end

+  describe 'optional values' do
+    subject(:struct) do
+      Class.new(Dry::Struct) do
+        attribute :person, Dry::Struct.optional do
+          attribute :name, Dry::Types['strict.string']
+        end
+      end
+    end
+
+    it 'sets missing values using default-value types' do
+      attrs = {}
+
+      expect(struct.new({}).to_h).to eql(attrs)
+    end
+  end
+