`s.race((a: ta, b: tb, …))` takes a named tuple of already-spawned
`*Task(..)` handles, suspends the calling fiber until the FIRST task is
ready, and returns a comptime-synthesized tagged-union (`RaceResult`)
mirroring the tuple's labels — variant NAME = the tuple label, payload =
that task's result type. After picking the winner it CANCELS and JOINS
every loser, so no loser fiber outlives the call (structured concurrency).
- `RaceResult($T) -> Type` projects each `*Task(R)` element to `R` via
`field_type(pointee(field_type(T, i)), 0)` and mints the union with
`make_enum` (the 0649 composition shape).
- `race` Phase 1 registers the caller as waiter on all pending tasks and
parks; on wake it DEREGISTERS from every task (a later loser completion
must never wake it again) and re-scans, lowest-index-first. Phase 2
builds the winner variant with `make_variant`. Phase 3 cancels + joins
each loser one at a time — only the joined loser carries a waiter, so no
other completion can wake the caller mid-join.
- Join correctness rides a new `Task.finished` flag, set at the very end of
the `go` worker body (after the work ran OR was skipped on an early
cancel) and checked before parking, so a worker that finishes between the
cancel and the park can't be lost. Cancellation is cooperative (M:1, no
preemption): a loser parked mid-`sleep` runs to its natural end, its value
discarded — `race` returns only once every loser has `finished`.
The tuple must be NAMED; a positional `._0`/`._1` form is future work.
Locked by examples/concurrency/1821 — three tasks (i64/bool/f64) sleeping
10/20/30ms, shortest wins, losers cancelled + joined; byte-identical on
aarch64-macOS and aarch64-linux (deterministic virtual time).
Completes comptime-cursor tuple indexing (started by the read path in
fee86adf) and unblocks the `race` runtime synthesis. Five enablers:
1. Named-tuple-literal type inference preserves element NAMES. A
`.(a = x, b = y)` passed DIRECTLY as a `$T` argument inferred to a
tuple with `.names = null`, so `field_name(T, i)` reflected "" and a
`make_enum` over those labels collided on the empty name. The typer
now mirrors `lowerTupleLiteral`'s name capture.
2. `inferExprType` resolves a comptime-constant tuple index to the i-th
field's CONCRETE type (the inference sibling of the fee86adf read
path), so `tup[i].field` / methods / comparisons on it resolve.
3. Tuple-element L-VALUES by comptime index — `tup[i] = v`,
`tup[i].f = v`, `@tup[i]` — lower to a typed `structGep` of field i
across all four paths (`lowerAssignment`, the multi-assign store,
`lowerExprAsPtr`, and address-of-index). Previously each emitted an
`index_gep` with a `ptrTo(.unresolved)` element type (a tuple has no
uniform element) that panicked at LLVM emit. An out-of-range comptime
index now diagnoses loudly on every path instead of falling through to
that panic.
4. A user generic `($X..) -> Type` call is recognized as type-shaped
(`isTypeReturningCallNode`), so it can bind a `$E: Type` parameter —
e.g. `make_variant(RaceResult(T), i, …)`. The static
`isTypeShapedAstNode` only knew the type-returning builtins
(field_type/pointee/type_of).
Locked by examples/comptime/0652 (read, fee86adf) and 0653 (store +
address-of + element-pointer field store).
`tup[i]` where `i` folds to a compile-time integer (an `inline for`
cursor or a literal) now reads the i-th tuple field with its CONCRETE
type instead of failing with "cannot index a value of type '(…)'".
A tuple's elements are heterogeneous, so there is no runtime
element-indexing op — a comptime index lowers exactly like the `.N`
field-access path (a `structGet` of the i-th field). A genuinely
runtime index into a tuple value still falls through to the existing
"cannot index a value of type" error (no single element type). A
comptime index out of range gets a dedicated loud diagnostic.
This is the read side `race` needs: pull the i-th `*Task(T_i)` handle
out of a named-tuple param keeping its real type so field/method access
on it resolves.
Locked by examples/comptime/0652-comptime-tuple-cursor-index.sx.
The metatype system can MINT tagged-union types (`make_enum`) and READ them
(`field_count`/`field_name`/`field_type`/`field_value`); `make_variant` is the
missing WRITE side — build a value of a minted tagged-union `E` whose active
variant is `idx`, carrying `payload`. Needed when the variant is selected at
RUNTIME but the union was synthesized at comptime so its labels can't be spelled
as a literal `.label(payload)` — e.g. the `race` result: an `inline for 0..N (i)`
arm constructs the i-th variant of a synthesized result with the winner's value.
Pure sx in modules/std/meta.sx (NOT a compiler builtin): a minted tagged-union is
laid out `{ i64 tag @0, payload @ size_of(i64) }` (the compiler fixes `tag_type`
to i64 for minted enums), so make_variant zeroes the value then writes the tag and
payload at those offsets — the same offsets the compiler's own enum_init/payload
ops use. The header comment documents the minted-only / i64-tag layout coupling.
Adversarially reviewed (SHIP): the offset-8 payload assumption is exactly the
compiler's enum layout with no alignment hazard (the payload is an alignment-1
`[N x i8]` array immediately after the i64 header); complex payloads (multi-field
struct, string fat pointer, 40-byte struct) round-trip. Locked by
examples/comptime/0650-comptime-make-variant.sx (heterogeneous + complex payloads,
runtime-index selection via the comptime `case` form). Suite green (822/0).
A `return` inside an `inline if` / comptime `case` branch — itself inside an
`inline for`, under a runtime `if` — made the compiler wrongly reject the
function as "body produces no value" and DROP its trailing statements (e.g. a
trailing `return -1`).
Root cause: the inline-if branch lowering sets the global `block_terminated` flag
when its taken arm returns (control_flow.zig / stmt.zig `lowerInlineBranch`),
unlike a bare `return` STATEMENT which deliberately never sets it (precisely to
avoid leaking past an `if cond { return }` merge — see the comment at
stmt.zig:37-42). The enclosing runtime-`if`'s merge never reset the flag, so it
leaked past the merge and `lowerBlock` skipped the following statements as dead.
Fix: after the runtime-`if` switches to its merge block, set
`block_terminated = then_diverged and has_else and else_diverged` — the `if`
leaves the block terminated ONLY when both arms diverged with an `else` covering
the cond-false edge (otherwise the merge is reachable and the flag must be
false). Adds `else_diverged` tracking alongside the existing `then_diverged`.
Adversarially reviewed (SHIP): the reachability predicate is correct across all
arm/else/divergence cases; the both-arms-diverge case still sets true (preserving
prior behavior); value-ternary and inline-for-unroll paths are unaffected.
Regression: examples/comptime/0651-comptime-inline-if-return.sx (nested inline-if
and comptime `case`, both with per-arm returns, asserting the trailing return is
emitted). Suite green (822/0).
A comptime-type-call's `Type` result (`field_type(T, i)`, `pointee(P)`) could only
be used in a type-arg slot — not as a `Type`-typed struct-field value, a generic
`$P: Type` argument, or a nested type-call arg — when the index was an `inline for`
loop variable. It routed through value / generic-fn lowering ("cannot infer generic
type parameter" / "unknown #builtin field_type") instead of the type-call fold. This
is what blocked the variable-arity `race` result synthesis: a `($T) -> Type` builder
looping `field_type(pointee(field_type(T, i)), 0)` to mint a tagged-union.
Three coordinated changes route these through the SAME type-call fold (which folds
the index, including a loop var), so type-arg and value positions never disagree:
- `isTypeShapedAstNode` (type_bridge.zig): a `.call` to a type-returning builtin
(`field_type`/`pointee`/`type_of`, via new `isTypeReturningBuiltinName`) is
type-shaped, so generic-arg inference (buildTypeBindings Strategy 1) resolves it
via `resolveTypeArg` rather than failing value inference.
- `tryLowerReflectionCall` (call.zig): value-position `field_type`/`pointee` fold
to `constType(resolveTypeCallWithBindings(c))` — the value twin of the existing
`type_of` fold (every failure path already diagnoses before `.unresolved`).
- `field_name` (call.zig): folds to a const STRING via `memberName` when the type
resolves and the index is a compile-time constant (matching the runtime
`field_name_get` array exactly — same `memberName`, same "" for nameless
members); a dynamic index still emits the `field_name_get` instruction.
Adversarially reviewed (SHIP): no over-broadening (only type-demanding slots consult
isTypeShapedAstNode; only `$T: Type` slots are affected), no silent defaults (every
fold failure is preceded by a diagnostic; "" is the runtime-matching value for a
nameless member). Locked by examples/comptime/0649-comptime-typecall-composition.sx
(reflect a named tuple of `*Box(..)` handles → mint a tagged-union with the tuple's
labels, projecting `*Box(A)` -> `A`). Suite green (821/0). Unblocks PLAN-RACE step 2.
The int-returning type-query builtins now fold to a compile-time constant in
const-required positions (`inline for` bound, array dimension), like a plain
`K :: 3` const — previously they evaluated only as runtime values, so
`[field_count(S)]T` and `inline for 0..field_count(S)` were rejected as "not a
compile-time integer". This is what lets a `($T) -> Type` builder loop
`inline for 0..field_count(T)` to assemble a member list from a type's fields
(the `race` result synthesis).
The shared comptime-int folder `evalConstIntExpr` (program_index.zig) gained a
`.call => ctx.evalConstCallInt(node)` arm. The body-lowering ctx (`Lowering`)
implements it — resolve the type arg via `resolveTypeArg`, return
`memberCount orelse 0` / `typeSizeBytes` / `typeAlignBytes`, matching the runtime
value path in lower/call.zig exactly. `SourceConstCtx` delegates to its wrapped
Lowering; the stateless ctxs (`ModuleConstCtx`, `StatelessInner`, test `DimCtx`)
stub null (they cannot resolve a type-expr arg). A non-type-query call / wrong
arg count / unresolved type arg folds to null (not a comptime integer).
Adversarially reviewed (SHIP): the fold matches the value path across every type
kind, ctx coverage is complete, recursion is AST-depth bounded, no speculative
spurious diagnostics, `orelse 0` is field_count's definitional value for
non-aggregates (not a silent default). Locked by
examples/comptime/0648-comptime-typequery-const-fold.sx. Suite green (820/0).
Project a pointer type to its target: `pointee(*X)` -> `X`. The one reflection
primitive missing for the `race` result synthesis (`*Task(A)` -> `A` via
`field_type(pointee(*Task(A)), 0)`) — reflection could read aggregate fields but
was blind to a pointer's target type.
Mirrors the `field_type` builtin: declared `#builtin` in std/core.sx, resolved as
a lower-time type-call fold in resolveTypeCallWithBindings (src/ir/lower/generic.zig)
so it composes in any type-arg slot. `.pointer` -> pointee, `.many_pointer` ->
element; a non-pointer arg is a loud diagnostic + `.unresolved` sentinel (no silent
fallback). Adversarially reviewed (SHIP). Locked by
examples/comptime/0647-comptime-pointee-reflection.sx. Suite green (819/0).
PLAN-RACE step 1 of 6.
Plan the `race` async deliverable (roadmap A1): a structured first-wins over
the M:1 `Task` layer, returning a comptime-synthesized tagged-union mirroring
the input named tuple's labels. Identifies the one net-new compiler primitive
needed — `pointee($P: Type) -> Type` (project `*Task(A)` → `A`); everything else
(tuple reflection, union synthesis, the suspending runtime) is already in place.
Issue 0196: a named-tuple type ALIAS (`NT :: Tuple(a: i64, b: bool)`) loses its
structure — field access and reflection both fail on the alias, while the inline
and `$T`-type-parameter forms work. Not on the race critical path (race reflects
a tuple type parameter), filed for tracking.
`field_count` / `field_name` were broken on every non-struct/enum aggregate:
`field_count(Tuple(i64, bool))` silently returned 0 (a missing `.tuple` arm in
the count switches), and `field_name(tuple/array/vector, i)` SEGFAULTED — the
LLVM backend built a zero-length `[0 x string]` name array for those kinds while
sizing the runtime GEP at the (often non-zero) member count, so the indexed load
ran past the array.
Root cause was three+ parallel switches that each had to know how to count an
aggregate's members, and disagreed: `field_count` lowering and `memberCount` had
struct/union/tagged_union/enum/array/vector but no `.tuple`; the backend's
`field_name_get` build + GEP sizing had neither `.tuple` nor `.array`/`.vector`.
Fix:
- add the `.tuple` arm to `field_count` lowering (src/ir/lower/call.zig) and
`TypeTable.memberCount` (src/ir/types.zig; this also backs the COMPILER-API
`type_field_count` VM reader).
- unify the LLVM backend onto the single source of truth: both
`getOrBuildFieldNameArray` (reflection.zig) and `emitFieldNameGet`'s GEP sizing
(ops.zig) now derive from `memberCount` / `memberName`, so the name-array
length and the GEP array type can never diverge again — for any kind. A member
with no name (positional-tuple / array / vector element) reflects as "" (one
slot per member, always in-bounds); named-tuple elements recover their labels.
The array/vector clone was surfaced by adversarial review of the tuple-only fix.
Regression: examples/comptime/0646-comptime-field-reflect-tuple-array.sx exercises
field_count/field_name/field_type over struct, enum, positional + named tuple,
array, and vector. Full suite green (818/0). Unblocks the `race` synthesis, which
must reflect a named tuple's labels + element types.
Port library/modules/std/sched.sx to run on aarch64-linux alongside
aarch64-macOS, validated byte-identical on both via Apple `container`.
Per-OS bits are comptime-branched:
- MAP_AP (mmap MAP_ANON flag): linux 0x22 / macOS 0x1002.
- fd-readiness backend: epoll on linux, kqueue on darwin (epoll import
scoped to the linux branch). block_on_fd, the run-loop Mode-2 drain,
and cancel_io_waiter_for each branch; the epoll paths EPOLL_CTL_DEL on
fire and on early-wake (EPOLLONESHOT only disables a registration;
kqueue EV_ONESHOT auto-removes it).
- first-entry trampoline: a per-OS hand-written global-asm symbol becomes
a naked sx fn fib_tramp (mov x0,x19; br x20) + register-indirect
dispatch (spawn presets regs[1] == x20 == &fib_dispatch), dropping the
per-OS .global symbol entirely.
Fixes issue 0193 Bug A: the trampoline redesign bus-errored on the
go/wait/sleep capstone (1817) because fib_dispatch was not pinned to the
C ABI. Without an explicit ABI, fib_dispatch uses sx's internal calling
convention (x0 = implicit context, first arg self shifted to x1) while
the trampoline hands self over in x0 (C-ABI); on first entry the body
runs (x1 happens to alias self) but the closure then loads
regs[1] == &fib_dispatch as its first capture and re-invokes fib_dispatch
forever -> stack overflow -> bus error. Annotating fib_dispatch
`abi(.c)` pins it to the C-ABI (self in x0), matching the trampoline.
`abi(.c)` rather than `export` because the fn is reached only by address
through the trampoline, never by an external name -- so it needs the
convention, not a public symbol (it stays a local symbol). Root cause
found via lldb on an AOT build; confirmed against the compiler source.
Bug B (a top-level asm block wrapped in inline-if is dropped during the
comptime-conditional flatten) is carved out to issue 0194 (OPEN) -- no
live trigger remains, since the naked-fn trampoline sidesteps it.
1811/1814/1816/1817 run byte-identical on the aarch64-macOS host and in
an aarch64-linux container; full suite green (817/0). Documents the fiber
runtime in readme.md.
Drop experimental/Jai/Zig framing and the Acknowledgments section, trim
the verbose edge-case paragraphs (numeric limits, float narrowing,
reserved names, module visibility) to punchy summaries, and remove the
from-source build section. Describe sx as a programming language.
Port of std/sched.sx (the M:1 fiber runtime) to aarch64-linux. The epoll
bindings + std.event.Loop epoll backend are already committed and runtime-
validated (cc137002); this records the SCHEDULER port, which is WIP:
- WORKS, validated in an Apple `container` Linux VM: 1811 (round-robin) and 1816
(block_on_fd over the epoll fd path) run identically to macOS kqueue.
- Bug A: a register-indirect trampoline (naked fn + `br x20`, to avoid a per-OS
hand-written global-asm symbol) bus-errors on the 1817 go/wait/sleep capstone
on both platforms, though 1811/1816 work — unresolved.
- Bug B: wrapping the original global `asm` trampoline in an `inline if`/`case`
drops it (nm: fib_tramp U) in sched.sx's context, though every minimal repro
emits fine — a flatten/lowering interaction in src/imports.zig.
The WIP sched.sx port is preserved both in `git stash` and as
issues/0193-linux-fiber-port.patch. Two resolution paths (either suffices)
documented in the issue. sched.sx itself is left at HEAD (macOS green).
The std.event.Loop epoll backend is now runtime-validated, not just
lower-verified: a static aarch64-linux build of the 1632-equivalent Loop test
(plus the eventfd wake path) runs 6/6 green inside an Apple `container` Linux VM
(kernel 6.18 aarch64) — add_read, idle-timeout, readable+fd+udata, the MOD-mask
add_write path, the eventfd wake channel, and EPOLLRDHUP/HUP eof all behave
identically to kqueue (lone difference: nbytes is 0 on epoll). Update the
event.sx VALIDATION note (with the re-run recipe) and the fibers checkpoint;
the epoll deliverable is complete.
A `:=`-bound closure with no explicit `-> T` and a BLOCK body inferred its
return type via inferExprType(lam.body), which yields the last statement's
type. A block whose value comes only from early `return`s ends in a return
statement (void/noreturn), so the closure was built with a void return while
the body returned i64 — the call site then fed `i64 undef` and LLVM
verification failed. (A block whose tail referenced a block-local hit the
sibling failure: inferExprType returned .unresolved → an LLVM panic.)
Infer the return type exactly as a named fn does (resolveReturnType in
lower.zig): an arrow body `(params) => expr` uses the expression type; a block
body `(params) { stmts }` takes the first explicit `return <val>` type via
findReturnValueType, else void (the block tail is a discarded statement unless
an explicit `-> R` makes it the value). Regression test:
examples/closures/0313-closure-inferred-return-early.sx.
compiler.sx needs only `List` (string is a builtin), so import the std/list.sx
part-file instead of std.sx. Its standalone transitive footprint drops from
~16k to ~50 lines of IR. Enabled by core.sx now self-declaring its libc, so
list.sx → core.sx resolves without the std assembly.
Regenerates 40 .ir snapshots: compiler.sx sits in the std import graph
(std → cli → build → compiler), so narrowing its import shifts the
registration order in every std program, renumbering LLVM symbol suffixes
(@foo.N → @foo.N+1) and adding a redundant `declare void @out` (LLVM dedups
it). Verified the diffs are purely that — no .exit/.stdout/.stderr changed, no
instruction/type/constant changed — and the full suite is green (817/0).
core.sx owns the libc escape hatches (libc_write / libc_malloc / libc_free /
memcpy / memset, all `extern libc "..."`) but never declared the `libc`
#library constant — it free-rode on `#library` being program-global, satisfied
by other std modules (socket/fs/cli) in a full std build. So core.sx — and
list.sx, which imports it for Allocator/List — could not be imported without
assembling the whole std prelude (`extern library 'libc' is not declared`).
Declare `libc :: #library "c"` in core.sx itself. `#library` constants are
program-global and dedup, so this is harmless alongside the other declarers,
and it makes core.sx / list.sx self-contained — importable standalone. No
snapshot drift (a #library decl adds no type/global), full suite green 817/0.
Move OS / ARCH / POINTER_SIZE + the OperatingSystem / Architecture enums out of
build.sx into a new std/target.sx that imports NOTHING, so low-level code can
name the target enum types without dragging the build/std barrel (build.sx
transitively pulls std + compiler + bundle, ~16k lines of IR).
build.sx flat-imports target.sx so the decls stay registered in the standard
import graph (build.sx is reachable from std.sx — dropping it would shift every
std program's type table). This is not a re-export: flat import only splices
into build.sx's own scope. Consumers are unaffected — the compiler resolves
OS / ARCH / POINTER_SIZE by name (comptime constants), so `inline if OS`/value
reads need no import; a module that names the enum type imports target.sx.
No behavior change (full suite green, 817/0); the enum types stay in the same
import graph, so no .ir snapshot drift.
Add library/modules/std/net/epoll.sx — raw epoll bindings, the linux twin of
std/net/kqueue.sx — and branch std.event.Loop on `inline if OS` so the
OS-neutral readiness Loop runs on linux (epoll) as well as darwin (kqueue);
callers never see the backend.
epoll_event has no packed-struct primitive in sx, so it is modelled as an
arch-branched struct of u32 fields — { events, data_lo, data_hi } → 12 bytes on
x86_64 (matching __attribute__((packed))), { events, pad, data_lo, data_hi } →
16 bytes on aarch64 — every field 4-aligned, so the layout is byte-exact for the
kernel ABI with no packed attribute and no unaligned access. The fd is stashed
in data_lo (epoll echoes one data word, not the fd separately).
epoll.sx is self-contained (libc only, no build.sx): the `inline if ARCH`
selecting the struct is resolved by the compiler's flatten pre-pass, so the
module's IR stays small. The epoll backend is imported INSIDE event.sx's
`inline if OS == .linux` branch (not top level): event.sx rides the std.sx
barrel, so a top-level import would register epoll's types into every std
program's type table on darwin and drift every .ir snapshot.
The epoll Loop keeps a small per-fd registration table (combined EPOLLIN/OUT
mask via EPOLL_CTL_ADD/MOD/DEL), maps the fd back to the caller's udata, arms
EPOLLRDHUP so a peer half-close surfaces as Event.eof (matching kqueue EV_EOF),
and uses an eventfd as the cross-thread wake channel (kqueue's EVFILT_USER).
Validation: the kqueue path runs end-to-end on the macOS host (1632 unchanged);
the epoll bindings + ABI layout are corpus-locked ir-only by
examples/event/1633 (x86_64-linux, both arches probe-verified). The epoll Loop
is verified to lower clean for both linux arches and self-reviewed, but is not
corpus-snapshotted (a Loop example drags the std barrel → ~18k-line brittle IR);
runtime behavior validates on a linux runner.
A namespaced import's const (`m :: #import "lib.sx"; … m.CAP`) only ever
resolved as a runtime value — the const folders in program_index.zig had no
namespace-member arm, so a qualified const was rejected as an array dimension /
Vector lane / generic value-param and could not seed another const, while the
flat-import form worked everywhere.
Add a `lookupQualifiedConst` (+ float / float-typed twins) ctx hook: resolve
the alias via `namespaceAliasVerdictFrom` to its target module, then fold the
member from that module's per-source const cache (`foldQualifiedConstInt` in
lower/comptime.zig), pinned to the target source so nested const RHSs fold
there. Wire it into evalConstIntExpr / evalConstFloatExpr / isFloatValuedExpr —
both the expression-position field_access arm (`[m.CAP]T`) and the
type-argument dotted-name arm (`Vector(m.LANES, …)`, generic value-params).
Implemented on the source-aware ctxs (Lowering / SourceConstCtx); the
namespace-blind ModuleConstCtx / StatelessInner return null, so a qualified-const
dim reached only via the stateless type-alias path stays a clean unresolved-dim
diagnostic, never a fabricated length. Resolves correctly for array dims,
arithmetic, integral-float dims, Vector lanes, generic value-params, inline-for
bounds, and struct fields.
Regression: examples/modules/0842-modules-qualified-import-const-comptime.sx.
A failable function that returned by IMPLICIT success (no explicit
`return`) left its error-tag slot uninitialized, so a caller's `catch` /
`or` (or `main`) read a garbage tag and reported a phantom unhandled
error — and for value-carrying failables the success value was dropped.
The "no error" sentinel was only written on the explicit-`return;` path.
Unified all function-body-return lowering so the failable-success slot
is always written:
- void `-> !` fall-through: `ensureTerminator` (control_flow.zig) now
emits `ret constInt(0)` for a pure-failable end-of-body.
- value-failable trailing-expression success: `lowerValueBody`
(stmt.zig) routes through `lowerFailableSuccessReturn`.
- generic + pack-fn instances: `monomorphizeFunction` (generic.zig) and
`monomorphizePackFn` (pack.zig) now DELEGATE their body-return to
`lowerValueBody` instead of hand-rolling a `coerce`+`ret` that drifted
(covers generic/pack value-failables).
Also fixes the missing-value diagnostic guard added here: it now counts
`.err`-level diagnostics (new `DiagnosticList.errorCount`) rather than the
total list length, so a warning/note emitted while lowering the body
(e.g. an ObjC selector arity warning) can no longer suppress a genuine
"body produces no value" error — which previously shipped an
uninitialized return at exit 0.
Regressions: examples/errors/1061 (void fall-through), 1062 (value-failable
trailing expr), 1063 (generic value-failable trailing expr).
Two type-resolution paths silently resolved a non-type AST node in type
position to a zero-field `{}` struct that reached codegen with no
diagnostic:
- a dotted `type_expr` / field-access (`g.a`, `g` a runtime value) whose
prefix is not a namespace alias
- an `error_type_expr` (`!Name`) whose `Name` is not a declared error set
Now both reject loudly:
- `resolveTypeWithBindings` (lower.zig): "expected a type, found a value
'<name>' in type position" + `.unresolved`
- `checkTypeNodeForUnknown` (semantic_diagnostics.zig): validates a named
`!E` against the declared error-set names — "unknown error set
'<name>'" / "expected an error set after '!', found type '<name>'".
A bare `!` (void channel) and a declared `!E` in return position stay
valid; namespace-qualified types (`pkg.Type`) are unaffected.
Regression: examples/diagnostics/1195-diagnostics-non-type-in-type-position.
Rewrite specs.md tuple/failable/pack/UFCS/grammar sections to the new
syntax, update readme.md, and refresh stale tuple references in example
header comments. Also fixes two pre-existing doc inaccuracies surfaced in
review: drop the value-discarding `;` in the tuple-return examples, and
correct the §13 function-type grammar production (optional param list +
optional trailing `!` channel). Optional semantics unchanged.
current/CHECKPOINT-LANG.md logs the cutover.
Replace the bare-paren tuple grammar with explicit, position-unambiguous
forms, mirroring how structs work:
type `(A, B)` -> `Tuple(A, B)` (named keeps `:`)
value `(a, b)` -> `.(a, b)` (named uses `=`)
typed (new) -> `Tuple(A, B).(a, b)` (like `Point.{...}`)
failable `-> (T, !)` -> `-> T !`
`-> (T1, T2, !)`-> `-> Tuple(T1, T2) !` (channel outside Tuple)
Bare `(...)` is now grouping only, everywhere; a comma in bare parens is a
hard error with a migration hint. Grouping, function types `(A, B) -> R`,
param lists, lambdas, and match bindings are unaffected.
`Tuple(...)` is strictly a TYPE in every position (including `size_of` /
`type_info` args); a tuple VALUE comes only from `.(...)` (anonymous) or
`Tuple(...).(...)` (explicitly typed). A bare `Tuple(1, 2)` is a tuple
type with non-type elements -> rejected.
The ~110 tuple-bearing corpus files were migrated with a one-shot
AST-aware migrator (the `sx migrate` tool from the prior commit, removed
here). New examples: 0130 (new syntax), 0131 (typed construction), 1060
(named-tuple failable return). 1116 golden updated for the new hint text.
Temporary scaffolding for the tuple-syntax cutover. Parses old-grammar
.sx and rewrites tuple syntax to the new spelling:
- tuple TYPES `(A, B)` -> `Tuple(A, B)` (named keeps `:`)
- tuple VALUES `(a, b)` -> `.(a, b)` (named flips `:` -> `=`)
- 1-tuples / empty / spread -> `.(x)` / `.()` / `.(..xs)`, `Tuple(..Ts)`
- failable returns: the `!` channel stays OUTSIDE Tuple
`-> (T, !)` -> `-> T !`
`-> (T1, T2, !)` -> `-> Tuple(T1, T2) !`
AST-walk based: rewrites only `tuple_literal` / `tuple_type_expr` nodes
(function types, param lists, match bindings, arrays, struct literals,
Closure sigs, groupings are left untouched). Nested tuples rewrite
recursively as a single non-overlapping edit per outermost tuple.
Value-vs-type ambiguity (call-arg tuples whose elements could be types,
e.g. `size_of((Box, i32))`, empty `()`) is never guessed: such sites go
to a worklist. A non-empty worklist exits nonzero and suppresses the
"looks-done" stdout output unless `--force` is passed.
`sx migrate <f>` prints migrated source; `--dry-run` prints only the
worklist. Built against the old grammar; removed after the cutover.
File four issue write-ups discovered alongside the 0179 work:
- 0185: binary-op operand auto-unwrap silently miscompiles a NULL ?T
- 0186: closure VALUE call does not coerce arg to ?T parameter
- 0187: lambda with inferred return type + block body with early returns
mis-infers its return type
- 0188: closure-VALUE calls skip argument validation (arity + tuple spread)
Optional (?T) operands were implicitly unwrapped without proof of
presence, silently miscompiling a NULL ?T to garbage. Unwraps in
binary ops and other expression positions are now gated on flow
narrowing: a ?T value is only auto-unwrapped where control flow has
established it is non-null (the narrowed_refs set). Outside a narrowed
region, an implicit unwrap is rejected rather than producing garbage.
Touches the lowering pipeline (lower.zig + lower/{call,closure,coerce,
comptime,control_flow,expr,ffi,generic,pack,stmt}.zig). Adds optionals
examples 0919-0923 and closures example 0312 covering flow narrowing,
binop narrowing, no-implicit-unwrap rejection, and no closure leak of
narrowed state. Updates specs.md and readme.md.
The body-local #run fold in emitCall was effectively dead (gated on
args.len==0, but the __ct comptime wrapper always carries the implicit
*Context arg), so every body-local #run fell through to a RUNTIME call:
bridgeable shapes lucked into the right value; an unbridgeable shape
(e.g. [2][]i64) ran over --- storage -> garbage, exit 0, no diagnostic.
Fold any is_comptime callee (gated !enclosing.is_comptime so nested
metatype calls in a comptime wrapper's dead body aren't folded). On a
tryEval bail, distinguish a BRIDGE bail (result can't regToValue-
materialize -> error: comptime init of 'X' failed: <reason> +
comptime_failed, build fails, symmetric with the global #run path) from
an EXECUTION bail (VM can't run the body, e.g. NaN/extern -> runtime
fallthrough, preserving types/0150), via comptime_vm.last_bail_was_bridge
(reset at tryEval entry, set only at regToValue). The const name is
threaded onto the wrapper (comptime_display_name) so the diagnostic reads
the source name, not __ct_N.
Regressions: diagnostics/1204 (negative), comptime/0645 (positive).
Verified by 3 adversarial reviews, suite 801/0.
lowerIndexExpr fell through to an index_get with an .unresolved element
type for any non-indexable object (*T, *[]T, struct, scalar), reaching
codegen -> 'unresolved type reached LLVM emission' panic. Add a guard
after all indexable arms: if getElementType(obj_ty) is .unresolved and
obj_ty is itself resolved (genuinely non-indexable, not a prior-error
placeholder), emit a located 'cannot index a value of type <T>'
diagnostic + placeholder (hasErrors aborts before codegen). A single
pointer hints by pointee: ptr-to-scalar -> many-pointer/dereference;
ptr-to-array/slice -> dereference first. No false-positives (generics,
aliases, late-resolved, every indexable shape verified).
Regression: examples/diagnostics/1203-diagnostics-index-non-indexable.sx.
Verified by 3 adversarial reviews, suite 799/0. Filed adjacent pre-existing
panic 0184 (untyped positional .{ } literal with no target type).
The generic-?? wrong-fallback was not in lowerNullCoalesce: coercing
?A -> ?B (differing payload, e.g. the ?i32->?i64 call-arg coercion when
instantiating unwrap_or(99, ?i32)) routed through .optional_wrap, which
unconditionally unwrapped the source and re-wrapped as ALWAYS-PRESENT, so
a null became present-zero everywhere (args, returns, field init,
var-decl, ??). Add a CoercionPlan.optional_to_optional (conversions.zig)
+ a presence-preserving arm in coerceMode (coerce.zig): has_value ->
present: unwrap+coerce-child+wrap-present; absent: constNull(dst); merge
via a dst_ty block param. lowerVarDecl gains a !src_is_optional guard so
an annotated x : ?B = <?A> routes through the same arm (also makes
aggregate-payload var-decl ?[3]i64->?[]i64 / ?Concrete->?Protocol work).
Alias-optional struct-literal default already works (grouping + 0166);
a 1-tuple default ?(i32,) ?? 5 now emits a clean diagnostic instead of an
LLVM PHI abort (no implicit scalar->1-tuple coercion per spec).
Regressions: optionals/0916 (generic ??), 0917 (alias struct default),
0918 (var-decl optional->optional), diagnostics/1202 (1-tuple default) +
a conversions.test.zig unit test. Verified by 3 adversarial reviews,
suite 798/0.
opt?.xs[i] typed and lowered the index over the optional CONTAINER
(?[N]T); getElementType returned .unresolved, so index_get reached LLVM
with an unresolved element type and panicked. Mirroring the 0101
!-unwrap fix: add lowerOptionalChainIndex (optional_has_value -> some:
unwrap + index (index_gep+load for ?*[N]T, else index_get) +
optional_wrap; none: const_null; merge -> ?ElemType, element-optional
flattened). The typer + dispatch guard compute the element via
ptrToArrayElem(child) orelse getElementType(child), so value-arrays,
slices, many-pointers, AND pointer-to-array (?*[N]T) children resolve.
Null receivers short-circuit (no null deref).
Regression: examples/optionals/0915-optional-chain-array-field-index.sx.
Verified by 3 adversarial reviews, suite 794/0. Filed broader pre-existing
gap 0183 (indexing a non-indexable type panics instead of diagnosing).
(C) regToValue (comptime_vm.zig) gained no array arm, so a #run returning
an aggregate containing an array bailed 'reg->value: aggregate shape not
bridged yet'. Add an .array arm: read N elements at stride
typeSizeBytes(elem) from the array address, bridge each recursively via
regToValue -> an .aggregate Value (serializeAggregateValue already emits
arrays). Composes with struct fields, nested arrays, array-of-structs,
and the ?Arr optional payload; unbridgeable elements bail loudly.
(E) A global failing #run proceeded into LLVM emission and panicked
'unresolved type reached LLVM emission' when the unresolved const was
used. Add 'if (self.comptime_failed) return;' in emit() after Pass 0 so
it aborts cleanly (exit 1, the comptime diagnostic) across run/ir/build.
Regression: examples/comptime/0644-comptime-run-array-aggregate.sx.
Verified by 3 adversarial reviews, suite 793/0. Filed separate bugs found
during review: 0181 (optional-chain ?. to array field + index panics),
0182 (body-local #run unbridged silently miscompiles).
In type position, parentheses now mirror value position: (T) (a single
unnamed element, no trailing comma) is a GROUPING that resolves to the
inner type; (T,) is a 1-tuple; (A, B) a 2-tuple; named (x: T) and spread
(..Ts) stay tuples; (...) -> R stays a function type. This lets a
closure/optional/function type be parenthesized for readability without
silently becoming a 1-tuple:
[1](Closure(i64,i64) -> i64) // array of closures (issue 0177) -> 7
?(?i64) // genuine nested optional (issue 0165 intent)
Parser: src/parser.zig returns the inner node for a single unnamed
non-spread no-trailing-comma parenthesized type. formatTypeName (both
generic.zig diagnostics + types.zig reflection) now render a 1-tuple as
(T,) so the spelling is unambiguous and diagnostics are self-consistent.
The 0165 coerce/stmt note reworded accordingly.
specs.md §Type Syntax updated; basic/0036 wrap return -> (i64,); obsolete
diagnostic 1195 removed (?(?i64) now compiles); regression
examples/types/0201-types-parenthesized-type-grouping.sx added; 0414 .ir
golden regenerated for the (T,) rendering. Resolves 0177; updates
0165/0170. Verified by 3 adversarial reviews; suite 792/0.
The issue-0176 conformance gate was name-only, so an impl P for T with a
mismatched return/param type (or arity) built a wrong-ABI thunk that
silently miscompiled (exit 0, wrong value). firstUnimplementedMethod now
validates arity (after self), each param type, and the return type
against the protocol declaration, substituting protocol Self->concrete
via resolveProtoTypeSubSelf (recurses through pointer/many-pointer/
optional/slice/array so []Self<->[]T match; conservative .unresolved for
Self-in-generic-arg). Comparison is by structural formatTypeName
(alias/module/spelling independent); typesClearlyDiffer skips when either
side has an unresolved leaf at any depth, biasing against false-positives.
Regressions: diagnostics/1201 (negative), protocols/0420 (positive,
[]Self param). Verified by 3+3 adversarial reviews (a mid-fix []Self
false-positive was found and closed); suite 792/0.
The type-erased value type is spelled Any (capital), per specs.md and
type_resolver.zig. Lowercase 'any' is an undefined name that resolves to
an empty-struct stub, which is why ?any appeared to silently discard the
value. ?Any round-trips correctly (present/absent/unwrap all work), so
there is no Any-TypeId canonicalization bug. Reword the 0165 cross-ref
accordingly.
lowerNullCoalesce fed resolveOptionalInner's .unresolved (returned for a
non-optional lhs) into the merge-block params / optionalUnwrap / RHS
target type, reaching codegen and panicking 'unresolved type reached
LLVM emission'. Guard: when inferExprType(nc.lhs) is a resolved
non-optional type, emit a located diagnostic and bail; an .unresolved
lhs (prior error) is excluded to avoid double-report. ?? is optional-only
per specs.md (error unions use or/catch), so rejecting a failable lhs is
correct; comptime panic closed too.
Regression: examples/diagnostics/1200-diagnostics-null-coalesce-non-optional.sx.
Verified by 3 adversarial reviews, suite 790/0. Filed adjacent bug 0180
(?? lowering defects for generic/alias/tuple optional lhs).
The Optional->Concrete unwrap classify rule treated ?i64 -> bool as
unwrap+narrow (both builtin), silently yielding false for every optional
(present or null). specs.md defines no implicit optional->bool
conversion. Reject it: conversions.zig adds an optional_to_bool_reject
plan (dst == bool, child != bool); coerce.zig emits a located diagnostic
suggesting '!= null'. Covers arg/field-init/return via the shared
coerceMode. The if-opt presence test (issue 0164) is a separate path,
untouched.
Regression: examples/diagnostics/1199-diagnostics-optional-to-bool.sx +
conversions.test.zig unit test. Verified by 3 adversarial reviews, suite
789/0. Filed adjacent issue 0179 (whole implicit ?T->concrete unwrap
family silently miscompiles a null optional; design-touching).
Erasing a type to a protocol when it conforms only via a free function
(not an explicit impl P for T) built a vtable of unreachable thunks ->
SIGABRT on first dispatch, with no diagnostic. Per specs.md erasure is
impl-driven, not structural, so the erasure was never valid.
Add a conformance gate (firstUnimplementedMethod in buildProtocolValue,
src/ir/lower/protocol.zig): emit a located diagnostic when a protocol
method has no reachable impl, or when an impl method introduces its own
type params (signature mismatch — it bails lazyLowerFunction and would
reach the unreachable thunk). A std.debug.panic tripwire guards the
diagnostics==null path so a non-conforming erasure can never silently
ship as undef. Gate<->thunk equivalence verified bidirectional.
Regressions: protocols/0419 (positive struct-field dispatch),
diagnostics/1197 (no-impl) + 1198 (generic-method signature mismatch).
Updated memory/0808 (it erased a non-conforming type that never
dispatched). Verified by 3+1 adversarial reviews, suite 788/0. Filed
adjacent bug 0178 (protocol impl method type-mismatch silent miscompile).
Calling through an unwrapped optional closure (g!()) crashed with LLVM
'Called function must be a pointer!': the indirect-call catch-all else
arm emitted call_indirect on the whole {fn,env} closure struct with a
hardcoded .i64 return. The else arm now inspects inferExprType(callee):
a .closure callee dispatches through call_closure (threads env + ctx via
the [ctx, env, user_args] ABI, returns closure.ret); a plain fn pointer
uses call_indirect with the callee's real function.ret instead of i64.
The filed repro's ?(() -> void) spelling is a tuple-optional (now
diagnosed by the 0165 fix); the real ?Closure(...) layout was already
correct. Verified load-bearing (HEAD crashes) by 3 adversarial reviews,
suite 785/0. Regression: examples/closures/0311-closures-optional-closure.sx.
Filed adjacent bug 0177 (array-element closure direct call crashes).
0173: resolveArrayLiteralType gained no arm for [N]T/[]T heads, so a
([2]?i64).[...] head lost its ?i64 element type and a bare null reached
LLVM as const_null(.unresolved). Route structural heads through
resolveTypeWithBindings; validate an undefined element name in the head
via UnknownTypeChecker (semantic_diagnostics.zig) instead of a silent
empty-struct stub (no-silent-fallback).
0174: positional .{...} against a TUPLE target now coerces each element
to TupleInfo.fields[i] (was neither struct nor array, so uncoerced).
0175: a positional struct literal with a bare-variable element was
misclassified as a named shorthand (parser puns .{x} -> x=x), zeroing
the fields. has_names now consults the struct definition to reclassify a
punned non-field name as positional; positional coercion uses the
lowered value's real getRefType.
Regressions: optionals/0914, types/0199, types/0200, diagnostics/1196.
Verified by 4 adversarial reviews; suite 784/0. Filed adjacent bug 0176
(protocol-typed struct field method call aborts).
[N]?T arrays were corrupted: a positional literal .{ null, 7 } stored
bare T/null elements into {T,i1} optional slots because array elements
were never coerced (getStructFields is empty for an array, so the
i<struct_fields.len field-coercion gate never fired). A present element
then read back as absent and direct indexing segfaulted.
lowerStructLiteral's positional branch now computes array_elem_ty for
array/vector targets and coerces each element to it; lowerArrayLiteral
generalizes its slice-only coercion to coerce every element via
coerceToType (layout-aware: scalar->{T,i1}, pointer-sentinel->one-word,
array->slice, concrete->protocol). Verified by 3 adversarial reviews,
suite 780/0.
Regression: examples/optionals/0913-optionals-array-of-optionals.sx.
Filed adjacent pre-existing bugs: 0173 (typed .[null,..] element), 0174
(tuple positional-element coercion), 0175 (positional struct literal
variable element zeroed).
The RHS of a null-coalesce was lowered with no target type, so a bare
struct literal default (x ?? .{ ... }) produced a struct_init with
.ty == .unresolved that panicked in emitStructInit. lowerNullCoalesce
now saves self.target_type, sets it to the optional's resolved child
before lowering nc.rhs, and restores it (leak-free). Verified across
struct/slice/enum/tuple/protocol/nested-optional/generic child types by
3 adversarial reviews.
Regression: examples/optionals/0912-null-coalesce-struct-literal.sx.
Filed adjacent pre-existing bug 0172 (?? on a non-optional lhs panics).
In type position (T) is a 1-tuple (specs.md:843), so ?(?i64) is
optional(tuple(?i64)); assigning a bare ?i64 had coerceToType classify
.none and pass the value through, then optionalWrap built a corrupt
insertvalue that aborted the LLVM verifier. After coercing toward an
optional's child, verify the coerced type equals the child type
(stmt.zig decl-init + coerce.zig .optional_wrap); on mismatch emit a
located diagnostic (tuple-specific note only when the child is a tuple).
formatTypeName now renders tuples as (x: i64, y: i64).
Regressions: optionals/0911 (nested optional via alias, round-trip),
diagnostics/1195 (the mismatch diagnostic). Updated diagnostics/1101 +
protocols/0414 goldens for the improved tuple type-name rendering.
Verified by 3 adversarial reviews. Filed adjacent bug 0171 (?any child
not canonicalized).
