// Atomic compare-exchange dual-ordering validation: the FAILURE ordering may not
// be stronger than the SUCCESS ordering (LLVM rule). Here failure=.seq_cst (rank
// 3) is stronger than success=.relaxed (rank 0) → loud diagnostic, not invalid IR.
// Calls the intrinsic directly so the diagnostic span is stable (user file, not
// the lib forward site). Stream A (atomics) A.2.
#import "modules/std.sx";
#import "modules/std/atomic.sx";

main :: () {
    n : i64 = 0;
    _ := atomic_cmpxchg(i64, @n, 0, 1, .relaxed, .seq_cst);
}