# V3 step 6 — QBE harden + unicode (planned)

Status: not started.

## Scope

- Close every construct gap between "test language" and "compiler
  language": procedure types + indirect calls (needs QBE `call`
  through register + frame design spike first), `LONGINT` quads,
  set ops full lowering, `WITH`-field `VAR` actuals.
- Unicode (locked): `UCHAR` 32-bit codepoint, UString =
  `LONGCARD` count + codepoints, `U'..'/U".."` literals,
  strict-RFC3629 `LexUString` (bad bytes → lex error 234),
  `UCHR/CHR8/UORD`, `Utf8` syslib shared by lexer + output libs.

## Acceptance (planned)

- `U'é'`→`w 233`, overlong/surrogate/`>10FFFF`/truncated → 234,
  `CHR8(U'€')` traps, UString index/assign/HIGH = array rules,
  round-trip byte-identity; suite green.

## Files (planned)

- `compiler/src/M2.atg` (`ustring` token, grown `LexString` buffer);
  `runtime/syslib/Utf8`; `QbeGen` UString `data` emission.
- This file filled in on landing.