fix(ownership): clear the enclosing killed set when a while condition contains break or continue - #13523

Problem

The last-use analysis parks the enclosing loop's "guaranteed reassigned" facts (killed) on the side while it walks a nested while, so a break/continue written in that inner condition — which targets the enclosing loop — erased a scratch copy instead of the real facts. The compiler then kept a move decision the break had invalidated: the clone protecting

while i < n {
    let mut y = x;          // must clone: the break below can skip `x = [v, v, v]`
    y[0] = 9;
    ...
    while ({ if i == 1 { break; } j < 3 }) { j = j + 1; }   // targets the OUTER loop
    x = [v, v, v];          // skipped when the break fires
}

was never emitted, y[0] = 9 wrote through x's buffer in place, and a release nargo silently returned [9, 9] instead of [1, 9] (a debug build rejects the program via the rc_invariant validator instead).

This is the residual half of noir#13153: that fix propagated has_break across exactly this save/restore boundary but not killed, and the break_dependent_uses set it introduced is consulted only by the confirmed_moves partition, never by loop-exit truncation.

Fixes noir-lang/noir-claude#1702.

Fix

Mirror the existing has_break propagation for killed: after restoring the enclosing set, clear it when the condition contained a break/continue — the same effect the jump would have had if the enclosing facts had been in place when it was traversed.

Tests

The first commit is red (against the buggy compiler), the second is the fix:

• execution_success/regression_while_condition_break_killed and regression_while_condition_continue_killed (the continue witness fires on the final iteration, so no later reassignment masks the corruption). Both sit alongside the three regressions noir#13153 shipped, which keep passing — the fix does not over-clone the shapes they pin.
• Two ownership unit tests snapshotting the move/clone decision at the pass boundary; the fix flips their snapshots from let mut y$l5 = x$l2; to let mut y$l5 = x$l2.clone();.

Validation: full noirc_frontend (2228) and noirc_evaluator (1961) suites, all 128 loop/break-related execute tests, AST fuzzer smoke, clippy, fmt.

🤖 Generated with Claude Code