Surface rename of the signed integer family: s1..s64 become i1..i64
(u1..u64, usize, isize unchanged). 'string' keeps the s-prefix arm in
name classification; width parsing moves to the i-prefix arm next to
isize.
Internal TypeId tags follow the surface (.s8/.s16/.s32/.s64 ->
.i8/.i16/.i32/.i64), as do mono-key mangle fragments (ptr_i64,
tu_i64_bool) and all display/diagnostic formatting (i{d}).
Migrated in the same sweep: stdlib + examples + issue repros + FFI C
companions (shared symbol names like ffi_id_i64), expected
stdout/stderr/ir snapshots, specs.md, readme.md, CLAUDE.md/AGENTS.md,
implementation_plan.md, docs/, issue writeups. Vendored stb_image and
historical flow state left untouched.
zig build test: 426/426; examples suite: 595/595.
Completes the issue-0094 fix. attempt-1 made single-assign and address-of
diagnose a missing struct field; the stress-review found two remaining defects
in that change:
1. lowerMultiAssign's `.field_access` target kept the pre-fix shape — a
struct-only loop that defaulted `field_idx 0` / `field_ty .unresolved` on a
miss, then built the GEP and stored unconditionally. A missing field
(`p.q, y = 2, 3`) silently wrote field 0 (printed `x=2 y=3`, no diagnostic),
and a valid promoted-union / tuple member at a non-zero offset corrupted
field 0 instead of its own slot.
2. attempt-1's new union branch in lowerExprAsPtr resolved only DIRECT union
field names, so `@v.x` on a promoted anonymous-struct member reported
"field 'x' not found on type 'Vec2'" even though `v.x = 41` worked.
Both lvalue-pointer sites and the multi-assign store now route through one
shared resolver, `fieldLvaluePtr`, that handles struct fields, union direct
fields, promoted anonymous-struct union members, and tuple elements, and
returns null (no field-0 / `.unresolved` default) on a genuine miss. Each
caller emits the read path's `emitFieldError` on null. This collapses the
three previously-divergent field-lvalue walks into one, fixing the
multi-assign missing-field corruption, the promoted-member over-rejection,
and (as a side effect of correct resolution) non-zero-offset promoted-union
and tuple multi-assign stores. The types.zig tripwire is untouched.
Regression tests:
- examples/1145 extended: multi-assign missing field (`p.r, y`) errors, exit 1.
- examples/0166 (new): promoted union member written and address-of'd,
including a non-zero-offset member (`@v.y`), compiles and runs.
- src/ir/lower.test.zig: multi-assign missing-field field-not-found unit test.
