"An open class or interface, with open type arguments.
 For example, `List<T>` is an open interface type, with a type argument which is the
 [[OpenTypeVariable]] `T`."
shared sealed interface OpenClassOrInterfaceType
    of OpenClassType | OpenInterfaceType
    satisfies OpenType {
    "The class or interface declaration for this open type."
    shared formal ClassOrInterfaceDeclaration declaration;
    "The extended type of this open type."
    shared formal OpenClassType? extendedType;
    "The satisfied types of this open type."
    shared formal OpenInterfaceType[] satisfiedTypes;

    "The set of open type arguments."
    shared formal Map<TypeParameter, OpenType> typeArguments;

    // FIXME: pretty sure we're missing an optional container type here