114 produce obligation lost to continuation

✓ Passing Passing: the compiler rejects this program as expected.

Code

// The `->` twin of 330_113: an obligation PRODUCED through a value-return
// subflow crosses the subflow boundary intact and is still enforced at the
// caller's flow exit, continuation and all.
//
// Worth its own pin because it is the shape that survives a subflow boundary —
// the obligation reaches the caller through `fetch`'s declared return type
// rather than from the minting call directly. An exit check wired only at the
// direct call site would satisfy 330_113 and leave this one unguarded, so the
// pair is what pins "`:` bind and `->` produce carry obligations identically".
import std/io
import app/lantern

tor fetch { } -> *app/lantern:Lantern<lit!>

fetch = app/lantern:light(): l -> l

fetch(): lamp |> std/io:print.ln("in the dark")

input.k

Supporting Files

// The lantern is a resource with a lifecycle the type system knows about.
// `light` mints <lit!>. `douse` is the only thing that consumes it. A delve
// that ends with the lantern still burning is not a losing game — it is a
// program that does not compile.

const std = @import("std");

const Lantern = struct { oil: i32 };

~pub tor light { } -> *Lantern<lit!>

~proc light|zig {
    const l = std.heap.page_allocator.create(Lantern) catch unreachable;
    l.* = Lantern{ .oil = 3 };
    std.debug.print("You strike the lantern. It catches.\n", .{});
    return l;
}

~pub tor douse { lamp: *Lantern<!lit> }

~proc douse|zig {
    std.debug.print("You pinch the wick. Dark.\n", .{});
    std.heap.page_allocator.destroy(lamp);
}

lantern.kz

Actual compiler output

error[KORU030]: Resource 'lamp' carries obligation <lit!> was not discharged. No tor accepts <!lit>.
  --> tests/regression/300_ADVANCED_FEATURES/330_PHANTOM_TYPES/330_114_produce_obligation_lost_to_continuation/input.k:17:0

❌ Compiler coordination error: Phantom semantic validation failed
   (set KORU_BACKEND_TRACE=1 for the backend return trace)

Must contain:

was not discharged

Flows

subflow ~fetch click a branch to expand · @labels scroll to their anchor

light

flow ~fetch click a branch to expand · @labels scroll to their anchor

fetch

Test Configuration

MUST_ERROR

Compiler Flags:

--auto-discharge=disable

← 113 named capture obligation undischarged 115 branch payload obligation survives continuation →