Threads an `Io` capability onto `Context` exactly like `Allocator`: a
`protocol #inline` whose process-wide default is a stateless `CBlockingIo`
(the mirror of `CAllocator`), installed in `__sx_default_context`.
Library (library/modules/std):
- core.sx: `Io` protocol (spawn_raw / suspend_raw / ready / poll / now_ms /
arm_timer) + `SpawnOpts` / `PinTarget` / `ParkToken`; `Context` gains an
`io: Io` field LAST (allocator stays index 0, data stays index 1).
- io.sx (new): `CBlockingIo` + `impl Io` (blocking M:1 semantics — now_ms is
a real monotonic clock, the rest are no-ops/0; suspend never called);
`Future($R)` { value; state: FutureState; err: IoErr; park; task; canceled:
Atomic(bool) } with `Value :: R`; the async ergonomic layer
`async` / `async_void` / `await` (value-carrying `(R, !IoErr)`) / `cancel`.
Built with the verified `= ---` + field-assign + `Closure(..$args) -> $R` +
`..$args` idiom (NON-void $R only — Future(void) is deferred per issue 0150).
- std.sx: re-export the Io surface + the io.sx tail.
Compiler (src/ir):
- protocol.zig `emitDefaultContextGlobal` + comptime_vm.zig
`materializeDefaultContext`: both materializers of `__sx_default_context`
now build the inline CBlockingIo->Io vtable (7 words) at the new field.
- stmt.zig `lowerPush`: `push Context.{...}` now INHERITS omitted fields from
the ambient context (seed the slot from current_ctx_ref, overwrite only the
literal's named fields) — correct capability-bag semantics, so the partial
`push Context.{ allocator = X }` sites don't zero a null `io` vtable.
- protocols.zig + lower.zig + error_analysis.zig: record protocol-impl method
names so the "declared `!` but never errors" lint skips a conforming impl
whose `!` is dictated by the protocol contract (e.g. Io.suspend_raw).
37 `.ir` snapshots regenerated: layout-only (the Context type now carries the
Io field, shifting type-table numbering); no stdout/stderr/exit changes.
The blocking Io + now_ms + Future/async work when `async` is called with the
receiver passed explicitly; the user-facing UFCS form `context.io.async(...)`
is blocked on a separate UFCS generic-inference bug (filed next).
Suite: 726 ran, 0 failed.
Mechanical src/ rename of the linkage-family identifiers whose extern_* target is
collision-free: callForeign→callExtern, marshalForeignArg→marshalExternArg,
dedupeForeignSymbol→dedupeExternSymbol, foreign_name_map→extern_name_map,
is_foreign_c_api→is_extern_c_api. Snapshot-neutral (internal only); suite green
(646 corpus / 444 unit, 0 failed).
Deferred (need per-site analysis — target name already exists): is_foreign↔is_extern
(38 existing), foreign_lib/foreign_name↔extern_lib/extern_name (15/16 existing),
foreign_expr (still built by c_import.zig auto-synthesis). Runtime-class family
(ForeignClassDecl etc. → Runtime*, Decision 5) is Phase 9.2.
emitProtocolDispatch now requires the user-arg count to equal the
protocol method's parameter list — exact, since protocol signatures
have no defaults, packs, or variadics — and emits the same
"expects N arguments, but M were given" diagnostic plain calls get.
Previously extra args were silently dropped (and missing args left the
thunk reading garbage). The dispatch gains the call-site span for the
diagnostic. examples/1634 pins the rejection; full sweep confirms no
existing code relied on the leniency.
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.
Review follow-up to the ARCH-B split (comment/import hygiene only, no
code changes):
- Section banners that travelled to the wrong file with the B1-B8 cuts
are reworded to describe the section that actually follows (e.g.
stmt.zig's trailing "Expression lowering", expr.zig's "Control flow"
before lowerChainedComparison) or deleted where nothing follows
(4 trailing-at-EOF banners). ffi.zig's facade note no longer claims
the IMP builders "stay here" (they live in lower/objc_class.zig);
protocol.zig's namespace-lookup banner now points at
pack.zig:resolvePackProjection for the orchestrator.
- lower.zig's two lower/expr.zig alias blocks (B8.1 + B8.2 appends)
merged into one.
- 448 unused header decls pruned from the 15 lower/*.zig files (each
had inherited lower.zig's full import block; pruned to fixpoint so
cascading type-extraction consts went too).
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 13-method protocol cluster (protocol decl
registration, param-protocol instantiation, thunk creation, vtable
globals, protocol-value construction, dispatch emission, impl lookup)
into src/ir/lower/protocol.zig. 13 fn aliases on Lowering keep all call
sites unchanged.
Two pub nested types travelled with the run (ProjectionPosition,
PackProjection) and are re-exposed via Lowering type aliases; they are
pack-domain types and may relocate to lower/pack.zig in B7.2.
Method pub-flips: allocViaContext, callForeign, genericInstanceMethod,
monomorphizeFunction.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
