C# has type safe anonymous types. //Anonymous type with integer property var foo = new {Number = 1}; //Compile time error if you try to assign a th

C# has type safe anonymous types. //Anonymous type with integer property var foo = new {Number = 1}; //Compile time error if you try to assign a the integer property to a string string s = foo.Number; An object is just a fancy map, after all... These are also immutable by default, which probably makes them even more relevant to this DOA discussion.