// A `!void` error singleton (tag-only) across
// return / let-init / assign / call-arg positions, plus a wide (str) success
// payload exercising CX/R8 zeroing on the tag-only return. Migrated from
// test/wcc/949_void_error_singleton_run.c (value rows; C driver asserted cs==ww .s).

package void_error_singleton_test;

type too_long = !void;

fn f_ret_singleton() (i64 | too_long) = {
	return too_long;
};

fn f_ret_success() (i64 | too_long) = {
	return 42i64;
};

fn use_callarg(r: (i64 | too_long)) i32 = {
	match (r) {
	case let v: i64 => return 1;
	case too_long => return 0;
	};
	return 2;
};

fn f_wide(ok: bool) (str | too_long) = {
	if (ok) { return "hello"; };
	return too_long;
};

@test fn return_singleton() void = {
	match (f_ret_singleton()) {
	case let v: i64 => { assert(false); };
	case too_long => { };
	};
};

@test fn return_success() void = {
	match (f_ret_success()) {
	case let v: i64 => { assert(v == 42); };
	case too_long => { assert(false); };
	};
};

@test fn letinit_singleton() void = {
	let e: (i64 | too_long) = too_long;
	match (e) {
	case let v: i64 => { assert(false); };
	case too_long => { };
	};
};

@test fn assign_singleton() void = {
	let e: (i64 | too_long) = 5i64;
	e = too_long;
	match (e) {
	case let v: i64 => { assert(false); };
	case too_long => { };
	};
};

@test fn callarg_singleton() void = {
	assert(use_callarg(too_long) == 0);
};

@test fn return_singleton_wide() void = {
	match (f_wide(false)) {
	case let s: str => { assert(false); };
	case too_long => { };
	};
	match (f_wide(true)) {
	case let s: str => { assert(s.len == 5); };
	case too_long => { assert(false); };
	};
};