What is the shortest way to define an immutable token of unique type?

[Per Nordlöw]

On Monday, 15 March 2021 at 09:45:44 UTC, Per Nordlöw wrote:
> and if possible have it be lowered to a builtin tuple
>
>     immutable (int, int) hex;

Forget about the tuple lowering. It doesn't have the fields 
accessible by name.