093 flat phantom bind chain

// Pins: a flat top-level chain of phantom bare-return binds should thread the
// obligation across EVERY link. `make(): h` yields <owned!>; each transform
// consumes <!owned> and re-issues <owned!> via its own bare return, so the
// obligation must ride the `: a` / `: b` bindings the same way it rides a
// subflow back-edge (330_074/082/085, which only ever thread through a loop).
// Single flat bind (make(): h |> fin(h)) already works; the second bind onward
// is where the obligation is currently dropped (KORU030 on every link).
const std = @import("std");
const Handle = struct { n: i32 };

~event make {} -> *Handle<owned!>
~proc make|zig {
    const h = std.heap.page_allocator.create(Handle) catch unreachable;
    h.* = .{ .n = 0 };
    return h;
}
~event t1 { h: *Handle<!owned> } -> *Handle<owned!>
~proc t1|zig { h.n += 1; return h; }
~event t2 { h: *Handle<!owned> } -> *Handle<owned!>
~proc t2|zig { h.n += 1; return h; }
~event fin { h: *Handle<!owned> }
~proc fin|zig { std.debug.print("n={}\n", .{h.n}); std.heap.page_allocator.destroy(h); }

~make(): h |> t1(h): a |> t2(h: a): b |> fin(h: b)