What literal expression has type `void`?

In Zig 0.9, I need a literal expression that has type void, for use as the context parameter to std.sort.sort, so that my lessThan function signature is semantically accurate. Is there some?

I tried these but to no avail:

const ek = @import("std").io.getStdOut().writer();
test "void" {
    const kandidati = .{ type, u0, .{}, void, null, undefined };
    inline for (kandidati) |k|
        try ek.print("{}, ", .{@TypeOf(k)});
    try ek.print("\n", .{});
}

giving

Test [0/1] test "void"... type, type, struct:31:37, type, @Type(.Null), @Type(.Undefined), 
All 1 tests passed.

I don't want to use a dummy variable like const v: void = undefined;; that's too verbose.

For reference, using void as the context parameter to std.sort.sort with a lessThan function that takes a parameter of type void, gives an error message like

error: expected type 'fn(type,anytype,anytype) anytype', found 'fn(void, Type1, Type1) bool'

The expressions void{}, @as(void, undefined), and {} have type void, for example. You can see {} used in the standard library test cases for std.sort.sort.

The "canonical" way of getting the void value is to use an empty block.