015 reject binding on void branch

// The void half of the linear bind-or-discard rule (KORU101):
// a branch that carries NO payload must be handled bindingless — there is
// nothing to bind, so there is nothing to discard either. `| done _ |>` is
// a lie about the data flowing through the program.
//
// Mirror of KORU030 ("branch has payload but no binding"). Together they are
// the full linear discipline: payload => bind or discard; void => bindingless.
const std = @import("std");

~event check {}
| ok i32
| done

~proc check|zig {
    return .done;
}

~check()
| ok _ |> _
| done _ |> _