const std = @import("std");

const MyUnion = union(enum) {
    SingleInt: u8,
    String: [5]u8,
};

fn createInstance(tag: @TagType(MyUnion), data: var) MyUnion {
    var instance: MyUnion = undefined;

    // Is something like this possible?
    // instance[tag] = data

    return instance;
}

pub fn main() void {
    const single_int = createInstance(MyUnion.SingleInt, 42);

    std.debug.assert(std.meta.activeTag(single_int) == MyUnion.SingleInt);
}