021 for auto done ok

✓ Passing This code compiles and runs correctly.

Code

// TEST: Auto-discharge at | done |> _ is allowed
// STATUS: IMPLEMENTED
//
// When an obligation is created OUTSIDE a for-loop, it can be
// auto-discharged at | done |> _ (runs once after loop completes).
// The compiler inserts the close call automatically.
//
// Here: Open file before loop, auto-discharge at done via _.
//
// Expected: Compiles successfully, auto-inserts close at done

~import "$std/control"
~import "$app/fs"

~app.fs:open(path: "outer.txt")
| opened _ |>
    std.control:for(0..3)
    | each _ |> _  // Loop body, obligation flows through
    | done |> _    // Auto-discharge inserts close here (runs once)

pub fn main() void {}

input.kz

Imported Files

// Library module: fs
// Defines filesystem operations with cleanup obligations

const std = @import("std");

// File type with phantom states
const File = struct {
    handle: i32,
};

// Open a file - returns opened! state (requires cleanup)
~pub event open { path: []const u8 }
| opened { file: *File[opened!] }

~proc open {
    std.debug.print("Opening file: {s}\n", .{path});
    const allocator = std.heap.page_allocator;
    const f = allocator.create(File) catch unreachable;
    f.* = File{ .handle = 42 };
    return .{ .opened = .{ .file = f } };
}

// Close a file - CONSUMES opened! state (disposes the resource)
~pub event close { file: *File[!opened] }
| closed {}

~proc close {
    std.debug.print("Closing file\n", .{});
    return .{ .closed = .{} };
}

fs.kz

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