nx_probe_mlneg_live.nx

nx_probe_mlneg_live.nx -- MUST-COMPILE-AND-COMPUTE WITNESS (contract changed by LN15, 2026-08-25): a multi-line binary op with leading MINUS now JOINS the expression above it (c == a - b == -1). `-` is a legal unary prefix, so before 2026-08-13 this parsed as a SEPARATE discarded `- b` statement -- the 2026-05-19 nx_force_cross silent-wrong-value shape (c kept only the first term; measured live exit 7, no diagnostic). 2026-08-13 refused it via the discarded-pure-expression check; LN15 made it correct instead. That check still stands and its irreducible witness is nx_probe_lone_operator.nx. EXPECT: BUILDS, runs exit 0 (c == -1, so the `c == 1` branch is NOT taken). If this ever REFUSES, LN15 has regressed; if it exits 7, the first-term-only split is back.