216 arrow discard into void sink

// The ACCEPTANCE boundary of the discard-into-void continuation: `| ok _ |>
// void-sink()` is legitimate — the `_` discards the payload explicitly, the
// void sink runs as a statement, and nothing expects a return (the arm is
// terminal). The linear bind-or-discard discipline is satisfied by the `_`.
// Pins: compiles, runs, prints "sink" — the discard does not leak a
// payload-return requirement into the void call.
~import std/io

const std = @import("std");

~pub tor stage { }
| ok string
| err string
~proc stage|zig { return .{ .ok = "hi" }; }

~pub tor void-sink { }
~proc void-sink|zig { std.debug.print("sink\n", .{}); }

~stage()
| ok _ |> void-sink()
| err e |> std/io:print.ln("err: {{ e:s }}")