dry-validation 0.13

AddressSchema = Dry::Validation.Schema do
  required(:street).filled
  required(:city).filled
  required(:zipcode).filled
end

UserSchema = Dry::Validation.Schema do
  required(:email).filled
  required(:name).filled
  required(:address).schema(AddressSchema)
end

UserSchema.(
  email: 'jane@doe',
  name: 'Jane',
  address: { street: nil, city: 'NYC', zipcode: '123' }
).messages

# {:address=>{:street=>["must be filled"]}}