gentype.nim

type
    Type[T] = object of RootObj
        typeName: string
        value: T

    String* = ref object of Type[string]

proc newString*(value: string): String =
    result = String(typeName: "String",
                    value: value)


let val: string = "test"

# Works:
let str: String = newString(val)

# Doesn't compile:
const str_const: String = newString(val_const)

# => (line 9) Error: cannot create null element for: [T]