57 piecewise stderr diagnostics in the checker spelled out
os.write(2, m.ptr, NNu64) with hand-counted byte literals. Replace the
38 hand-counted literal sites and 19 var sites with a tool-local
cerr(m: str) helper that takes .len off the str, eliminating the
off-by-one hazard. All 38 prior hand-counts were already correct, so
stderr is byte-identical. cerr lives in check.ww (not err.ww, which
ports err.c for the dead C-driven path); regen w6c + wwdump
combined.ww.
Hojun-Cho
ff333ce62d