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.
Two remaining siblings in F0.4's comptime-int path.
1. Type-returning function with a value param used as a TYPE annotation
(`b : Make(N, s64)` where `Make :: ($K: u32, $T: Type) -> Type`):
- `isValueParamPosition` (semantic_diagnostics) now also skips a value
param of a `fn_ast_map` type-returning function, so `N` is not walked
as the type name "N" ("unknown type 'N'").
- `resolveParameterizedWithBindings` routes a type-returning-function
name to `instantiateTypeFunction` (the `.call` path already did).
- `instantiateTypeFunction` resolves a general return-type expression
(`return [K]T`) with bindings active — not just struct/union returns.
`Make(N, s64)`, `Make(M + 1, s64)`, `Make(3, s64)` all resolve to one
`[3]s64`.
2. Oversized dim/lane fold panicked the compiler (0087): an array dim /
Vector lane folded to a valid i64 (5e9) then narrowed to u32 with an
unchecked `@intCast`. New single gate `program_index.foldDimU32` folds
via `evalConstIntExpr` then range-checks `[min, maxInt(u32)]`; the three
narrowing sites (resolveArrayLen stateful + stateless, resolveVectorLane)
all route through it and emit a clean diagnostic + halt instead of
panicking. Value-param args stay i64 until used as a dim/lane, where the
same gate checks them.
Regressions: examples/0208 (value-param type function), examples/1130
(oversized array dim clean halt), examples/1503 (oversized Vector lane
clean halt). Marks issue 0087 RESOLVED.
Gate: zig build, zig build test, bash tests/run_examples.sh — 398 passed,
0 failed, 0 timed out.
