fromutf8(in: []u8) (str | utf8.invalid) and the bytesub form per
ref/hare/strings/utf8.ha:22 and sub.ha:59. bytesub keeps its byte
asserts (ww extension over Hare; predates #7).
fromutf8 walks the utf8 decoder via utf8.next rather than the
shorter `utf8.validate(in)?` form. Two compiler bugs in the way:
cross-shape `(void | invalid) → (str | invalid)` propagation is
#19, and (void | !void) match-bind locals diverge between stages /
str→union lift SIGSEGVs in cstage — both filed as #48. The
decoder-walk form bypasses both and matches what
ref/hare/strings/utf8.ha actually does in source.
getopt.ww:314 caller updated to match the new (str | invalid)
return; bi+1 cannot hit a continuation byte in well-formed argv
(bi is a just-matched ASCII flag), so abort spells the precondition.
bytesub_cases rewritten as exhaustive match; new rows cover
start-on-continuation and end-on-continuation invalid arms plus an
end==s.len bypass. fromutf8_cases is new — Hare vector + edge
bytes + multibyte parity rows.
Hojun-Cho
6d006da26c