017 scope label loop

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

Code

// PIN: an obligation created inside a label-fold body and dropped at the
// @loop back-edge is refused — scope tracking traces @loop jumps back to
// #loop, sees the opened file goes nowhere on that edge, and raises KORU030
// ("discharge it before jumping"). Complements 330_075, which pins the
// same rule for a carried obligation dropped via an empty @loop().
~import app/fs
const std = @import("std");
~tor iterate { count: i32 }
| more i32
| fin i32
~proc iterate|zig {
    if (count < 3) {
        return .{ .more = count + 1 };
    }
    return .{ .fin = count };
}
~tor spin {} -> i32
~spin = #loop iterate(count: 0)
    | more n |> app/fs:open(path: "test.txt"): f |> @loop(count: n)
    | fin r -> r
~spin()

input.kz

Supporting Files

// Library module: fs
// Single disposal event

const std = @import("std");

const File = struct { handle: i32 };

// Open a file - returns opened! state (requires cleanup)
~pub tor open { path: string } -> *File<opened!>

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

// Close - the ONLY consumer of <!opened>
~pub tor close { file: *File<!opened> }

~proc close|zig {
    std.debug.print("Closing file\n", .{});
}

fs.kz

Actual compiler output

error[KORU030]: Label jump '@loop' drops cleanup obligation for 'f' - pass it as an argument or discharge it before jumping
  --> tests/regression/300_ADVANCED_FEATURES/330_PHANTOM_TYPES/330_017_scope_label_loop/input.kz:19:5

Must contain:

error[KORU030]

Flows

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

#loop iterate (count: 0)

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

spin

Test Configuration

MUST_ERROR

← 016 scope nested 018 auto discharge escaped obligation →