# Spec §"Multi-piece concat is left-to-right pairwise (NORMATIVE)" — overlapping-keys variant.
# Pairwise fold: join(obj1, obj2) → object-merge per S10.3 → {0:z, 1:y} (later "0" wins).
# Then join(merged, [a]) → numericObjectToArray triggers (list partner) → array-array concat.
# Expected: arr = ["z", "y", "a"].
#
# This fixture distinguishes a true left-to-right pairwise fold from a single-pass loop that
# converts each Object element independently. The disjoint-keys fixture (na03d) cannot detect
# the divergence — both algorithms produce the same answer when keys do not overlap.
#
# Multi-reviewer code review (2026-05-16) caught all 3 impls (ts/rs/go) initially shipping
# the single-pass loop variant; this fixture is the regression guard added in followup.
obj1 = {"0":"x","1":"y"}
obj2 = {"0":"z"}
arr = ${obj1} ${obj2} [a]