             return failingConstraints > 0
         }
 
-        internal static var Successful = Summary(errors: [])
-
         internal init(errors:[Error]) {
             self.errors = errors;
         }


            self.init(errors: errors)
        }

        public static func ==(lhs: Summary, rhs: Summary) -> Bool {
            return lhs.errors.map { $0.localizedDescription } == rhs.errors.map { $0.localizedDescription }
        }
    }
}

    /**
     The summary of a validation result.
     */
    public struct Summary {

        /**
         `[Error]` if the validation result is `.invalid`, `nil` otherwise.
