// Failable error-slot discard rejection (ERR step E1.8 — discard slice). The
// error slot of a value-carrying failable cannot be dropped on a bare
// destructure: it must be bound (`v, err := …`) and handled, or the failure
// routed through `try` / `catch` / `or value` (all of which strip the error
// channel, so they don't reach this check). Two rejected shapes here:
//   (1) omitting the error slot entirely (fewer names than slots), and
//   (2) binding it to `_`.
// This file is expected to FAIL compilation (exit 1).
//
// Run: ./zig-out/bin/sx run examples/236-failable-discard-reject.sx

#import "modules/std.sx";

E :: error { Bad, Empty }

pair :: (n: s32) -> (s32, s32, !E) {
    if n < 0 { raise error.Bad; }
    return (n, n + 1);
}

parse :: (n: s32) -> (s32, !E) {
    if n < 0 { raise error.Bad; }
    return n * 2;
}

main :: () -> s32 {
    a, b := pair(5);     // ERROR: error slot omitted (3 slots, 2 names)
    v, _ := parse(5);    // ERROR: error slot discarded with `_`
    return a + b + v;
}