sx/current/CHECKPOINT-MEM.md

# Memory Module — Progress + Issues Log

Tracking checkpoint for the mem.sx Zig-aligned implementation
(plan: `~/.claude/plans/tidy-doodling-cray.md`).

## Last completed step

- **Phase 1.4 — `valueToLLVMConst` upgraded to handle every interp
  `Value` variant.** The serializer at `emit_llvm.zig:734` used to
  collapse anything past int/float/boolean into `LLVMConstNull(ty)` —
  a silent fallback that emitted `{0, 0}` for any `#run` returning a
  struct, string, function pointer, or pointer. Replaced with a real
  walk: int/float/boolean as before; null_val → LLVMConstNull;
  void_val/undef → LLVMGetUndef; func_ref → func_map lookup;
  string → emitConstStringGlobal; aggregate → recurse via
  `LLVMStructGetTypeAtIndex` / `LLVMGetElementType`. The unsupported
  cases (heap_ptr/byte_ptr/slot_ptr/closure/type_tag) now bail loudly
  with a named diagnostic that includes the global name (per CLAUDE.md
  REJECTED PATTERNS — no silent unimplemented arms). Heap_ptr is
  deferred to Phase 1.4a (needs IR TypeId threaded down for cyclic /
  recursive heap content).

  Also closes the type-inference half of the same bug: `NAME :: #run
  expr;` with no annotation used to default to `s64` (silent fallback
  in `resolveType(null)`). `lowerComptimeGlobal` now infers from the
  expression's return type when no annotation is provided. The
  silent fallback in `resolveType` itself is left in place for other
  callers — separate audit, separate session.

  Regression test at
  `examples/134-comptime-aggregate-global.sx`: a `POINT :: #run
  make_point();` struct binding now prints the real fields instead
  of zeros, on both interp and codegen paths. 156/156 example tests
  + chess clean.

## Current state

Phase 0.0c shipped (allocator API on one-line `init` returning `*T`;
TrackingAllocator added). 148/148 tests pass.

Phase 0.2 verified across all known patterns. Phase 0.3 documented.

Phase 0 of the MEM plan is **COMPLETE**.

Fixed this session by paired sessions: issue-0038 (transitive
`#import`), issue-0039 (chess + stdlib migration to explicit imports),
issue-0040 (generic struct method dot-dispatch). All landed and
re-verified. Full gate green: 151/151 example tests + chess on macOS
/ iOS sim / Android with screenshots.

Phase 0 spike outcomes:
- **0.2** xx cast patterns — verified across 5 additional shapes
  beyond the issue-0037 regression.
- **0.3** chess allocator audit — documented; no chess-side
  migration needed.
- **0.6** `align_of($T)` builtin — landed. Mirrors `size_of` in
  inst.zig BuiltinId, lower.zig (registry + return-type + reflection
  handler), interp.zig (fallback), sema.zig (allowed-builtins list),
  lsp/server.zig (both completion tables), library/modules/std.sx.
  Smoke coverage added in `examples/50-smoke.sx` (u8/s32/s64/Point).
- **0.7** `#import` transitivity — surfaced and fixed via issue-0038.
- **0.8** `#foreign("c")` rename syntax — confirmed
  `#foreign libc "name"`.
- **0.9** generic UFCS dispatch — surfaced and fixed via issue-0040.
  Dot-call now works for struct methods with `$T: Type` parameters,
  so the plan's `a.create(MyType)` shape is viable.

issue-0041 (pointer type as type-arg) and issue-0042 (alias names in
`resolveTypeArg`) **FIXED**. Regression tests at
`examples/issue-0041.sx` and `examples/issue-0042.sx`. Scratch
verification: `size_of(*u8)=8`, `size_of(Ptr where Ptr::*u8)=8`,
`size_of(?u8)=2`, `size_of(Maybe where Maybe::?u8)=2` — all clean on
interp + codegen.

Also landed during 0041/0042: the silent `.s64` fallback in
`resolveTypeArg` is gone — unresolved type names now emit a real
diagnostic. Surfaced and removed two bogus `size_of(Complex)` /
`size_of(Sx)` calls in `examples/10-generic-struct.sx` that were
relying on the silent default. Caller-side speculative paths in
`buildTypeBindings` + `inferGenericReturnType` now gate the call
with `type_bridge.isTypeShapedAstNode` before invoking
`resolveTypeArg`. CLAUDE.md REJECTED PATTERNS gained a section
forbidding silent `orelse default` returns in compiler code.

Parser regressions introduced by the 0041 work fixed in
`src/parser.zig:hasFnBodyAfterArrow`:
- `(s: string) -> [:0]u8 { ... }` — added `.colon` to the
  return-type token walk.
- `(x) -> Closure(...) -> R { ... }` — added `.arrow` so nested
  return-type arrows continue the walk.
- `name :: (self: T) -> Ret;` inside `struct #compiler` — recognise
  trailing `;` as a method-decl terminator. Was silently dropping
  every `BuildOptions.*` method from `fn_ast_map`.

Full gate green: 151/151 example tests + chess on macOS / iOS sim /
Android with screenshots.

**Implicit Context refactor SHIPPED.** Every default-conv sx function
now carries `__sx_ctx: *void` at LLVM slot 0. `context.X` lookups
resolve through the lowering's `current_ctx_ref` — a one-indirection
load, no per-access walk, thread-safe by construction (each call
stack carries its own Context chain). `push Context.{...}` allocates
a fresh slot and rebinds `current_ctx_ref` for the body's lexical
scope. The `context` LLVM global is gone; the only runtime Context
is the static `__sx_default_context` (a CAllocator backing libc
malloc/free), installed at FFI-inbound entries (`main`, `Java_*`,
`JNI_OnLoad`) and used by the interp for `#run` evaluation.

What landed:
- `Function.has_implicit_ctx` flag + `Module.has_implicit_ctx`
  per-compilation switch (gated by `Context :: struct {...}` being
  present in the dep graph).
- Param prepend + call-site forwarding across every sx-to-sx path:
  direct calls, indirect through fn-pointer vars, protocol dispatch,
  closure trampolines, lambda trampolines, bare-fn trampolines,
  generic monomorphizations, comptime functions.
- `ConstantValue.func_ref: FuncId` variant so the static initializer
  for `__sx_default_context` can reference the CAllocator thunks.
- emit_llvm two-pass global emission: aggregates that name funcs by
  FuncId resolve them after `func_map` is populated.
- Interp: `defaultContextValue()` builds the Context aggregate on
  demand; `interp.call` bootstraps slot_ptr(0) when an entry function
  with implicit ctx is invoked sans args; `materializeCtxArg` derefs
  the caller's slot_ptr at every sx-to-sx boundary so callees can
  treat ref 0 as the Context aggregate; `.load` of an aggregate is
  passthrough; `.global_addr` of `__sx_default_context` returns the
  aggregate directly.
- `matchContextAllocCall` is GONE (commit `d415bcc`). Comptime now
  runs the full Allocator-protocol dispatch chain — the same IR
  codegen emits — by reusing the parent module instead of spinning
  up a separate `ct_module`. The interp gained raw-pointer paths
  (`index_gep`, `index_get`, `store`, `marshalForeignArg`,
  `asString`) so `context.allocator.alloc` bottoms out at host
  `libc_malloc` and the returned pointer survives downstream sx ops.
- `inst.Store` carries `val_ty: TypeId` so the interp's raw-pointer
  store honours the destination width — no more "assume 8 bytes"
  silent clobber. Regression test at
  `examples/132-comptime-typed-store-widths.sx` exercises every
  primitive width (u8/u16/u32/u64, s8..s64, bool, f32, f64) via
  comptime checksums compared to runtime checksums.
- Call-convention mismatch at bare-fn → fn-pointer coercion is now
  a compile error (commit `f886d5f`). The chess-debug sweep that
  surfaced the bug also moved `#foreign` decls to default
  `callconv(.c)` and fixed every consumer-side sx callback exposed
  to a C API. Regression test:
  `examples/131-callconv-mismatch-diagnostic.sx`.
- Interp silent-arm sweep (commit `e9df33a`). Every `else =>` arm
  has a named bail reason via `bailDetail` / `typeErrorDetail`.
  `.deref` and `.unbox_any` used to silently pass through arbitrary
  Value kinds — now enumerated. `#run const` errors no longer
  swallow into `void_val`; emit_llvm surfaces them via std.debug.
- C-side callback into sx requires `callconv(.c)` on the sx fn (and
  on any fn-pointer TYPE the user casts a C fn-pointer through).
  Tests adjusted: `examples/61-objc-roundtrip.sx`,
  `examples/62-objc-class.sx`, `examples/95..97-objc-block*.sx`,
  `examples/ffi-06-callback.sx`.

154/154 example tests pass (two new regression tests added: 131 and
132). Chess green on macOS / iOS sim / Android.

ISSUE-MEM-002 (the `context.allocator.alloc(size)` pattern-match
bypass) is FULLY CLOSED. User-typed `context.allocator.X` flows
through the real protocol vtable at codegen *and* runs the same
chain at comptime in the interp. No remaining shortcut.

## Next step

Phase 1.3 (closure env allocation through context) shipped in commit
`8e21cc5`. Phase 1.4 (codegen serializer for all interp Value
variants) shipped this session. Phase 1.2 (free / malloc through
context) was considered and **skipped** — `context.allocator.alloc
/dealloc` already works directly; wrapper-only `malloc`/`free` would
be lossy renames.

The `List(T)` allocator-arg work shipped earlier this session is
**outside the original MEM plan** but lives in the same problem
space (long-lived container growth silently capturing the wrong
allocator).

Open follow-ups, in roughly the order they make sense:

- **Phase 1.4a** — Thread IR `TypeId` (not just LLVM `LLVMTypeRef`)
  through `valueToLLVMConst` so `heap_ptr` values from `#run` can be
  serialized. Requires walking the struct/slice/primitive children
  recursively; cycle detection via `(heap_id, type_id)` visited set.
  Practical trigger: a `#run` that builds a `Widget.{}` and
  protocol-erases via `xx`, producing a `heap_ptr` to the boxed
  payload. None exists in-tree yet — surface it via a focused
  regression alongside the implementation.
- **`resolveType(null) -> .s64` audit.** The silent fallback at
  `lower.zig:8387` is still in place for every caller other than
  `lowerComptimeGlobal`. CLAUDE.md REJECTED PATTERNS forbids this
  shape. Survey callers; either make the default an error
  diagnostic or thread an inferred type per call site.
- **`tools/verify-step.sh` gate.** Run iOS sim + Android to confirm
  this session's GlyphCache + Metal/Gles3 sweeps + Phase 1.4 didn't
  regress non-macOS platforms.

## Phase 0.3 audit findings — chess allocator usage (closed)

After Step 5 / matchContextAllocCall removal, every consumer call
to `context.allocator.X` flows through the real protocol vtable.
This section is left for history — the audit drove which sites
needed migration, but no chess code actually needed any allocator-
API change. The sites that used to bypass the protocol via the
`.heap_alloc` pattern-match now dispatch through the inline
Allocator value naturally.

- `~/projects/game/main.sx` — 7 sites of
  `context.allocator.alloc(size_of(T))` for platform/GPU/pipeline
  state. Now real protocol dispatch.
- `~/projects/game/chess/game.sx` — `ChessGameState.init` captures
  `context.allocator` into a `parent_allocator: Allocator` field
  and restores it via `push Context.{ allocator = ... }`. Worked
  before, still works.
- `~/projects/game/chess/pieces.sx` — declares its own `free`
  bound to libc and calls it on a libc-malloc'd buffer (from a
  foreign reader). Intentional C-interop bypass — no change needed.
- `~/projects/game/quick.sx` — quicksort demo. Same flow as main.sx.

## Log

- **2026-05-25 (latest)** — Phase 1.4 shipped. `valueToLLVMConst`
  (`emit_llvm.zig:734`) replaced the primitive-only switch with a
  full serializer covering null_val, void_val, undef, func_ref,
  string, and aggregate (struct + array via
  `LLVMStructGetTypeAtIndex` / `LLVMGetElementType`). Unsupported
  variants (heap_ptr, byte_ptr, slot_ptr, closure, type_tag) bail
  loudly via `std.debug.print` with the global name. The call site
  at line 676 now passes `global.name` so the diagnostic locates the
  offending `#run` site. `lowerComptimeGlobal` (`lower.zig:6384`)
  infers the return type from the expression when the user omits
  the type annotation — closes the silent-s64 default for `NAME ::
  #run expr;` bindings. The broader `resolveType(null) -> .s64`
  fallback is left in place for other callers — flagged for a
  follow-up audit. Regression at
  `examples/134-comptime-aggregate-global.sx`. 156/156 + chess green.
- **2026-05-25 (penultimate)** — `List(T)` mutation API gained an optional
  trailing `alloc: Allocator = context.allocator` argument
  (`library/modules/std.sx`). Default-arg substitution previously
  only fired for identifier callees; extended to the generic-method
  dispatch path via new `appendDefaultArgs` helper at
  `lower.zig:7974-7991`, wired in at `lower.zig:5332`. Long-lived
  owners that grew internal Lists during render — `GlyphCache`,
  `DockInteraction`, `StateStore`, `Gles3Gpu`, `MetalGPU` — now
  capture `parent_allocator: Allocator` at init and forward it to
  every internal `.append` / `.alloc` / `.dealloc`. Chess panel-text
  regression (text vanished after the first move because GlyphCache
  hash + entries grew into the per-frame arena and died on reset)
  fixed end-to-end on macOS. specs.md §11 gains a "Default Parameter
  Values" subsection documenting the existing capability. Operator-
  precedence fix kept in `pipeline.sx` (`(self.frame_index & 1) == 0`
  instead of `self.frame_index & 1 == 0`, which was parsing as
  `self.frame_index & (1 == 0)` = always 0). All diagnostic logging
  added during the bug hunt has been stripped. 155/155 example tests
  green.
- **2026-05-25 (late)** — Interp silent-arm sweep (`e9df33a`).
  Every `else =>` arm has a `bailDetail` reason; `.deref` /
  `.unbox_any` previously silently passed through arbitrary Value
  kinds, now enumerated. `#run const` errors surface a real
  diagnostic via emit_llvm instead of becoming `void_val`.
  CLAUDE.md REJECTED PATTERNS gained the "silent unimplemented
  arms" section (`4de565b`). 154/154 + chess green.
- **2026-05-25 (mid)** — Typed raw-pointer stores (`f2b3868`).
  `inst.Store` carries `val_ty: TypeId`, threaded by
  `builder.store` and consumed by `storeAtRawPtr` to write exactly
  the declared destination width. Regression at
  `examples/132-comptime-typed-store-widths.sx` exercises every
  primitive width via comptime/runtime checksum comparison.
  `index_get` raw-pointer arm added (was bailing). Comptime init
  errors no longer swallow into zero.
- **2026-05-25 (mid)** — Drop `matchContextAllocCall` (`d415bcc`).
  Comptime now runs the full Allocator-protocol dispatch chain by
  reusing the parent module instead of spinning up a fresh
  ct_module. Interp gained `.int` / `.byte_ptr` arms in
  `index_gep`, `store`, `marshalForeignArg`, `asString`. Closes
  ISSUE-MEM-002 fully. JNI stub binding extended to call
  current_ctx_ref → &__sx_default_context (used to be gated on
  isExportedEntryName).
- **2026-05-25 (mid)** — Reject call-conv mismatch at bare-fn →
  fn-pointer coercion (`f886d5f`). `#foreign` decls now default to
  `callconv(.c)`. Library audit (`619aff8`) — all C-side callbacks
  already followed the rule; documented the one remaining gap
  (`xx <sx_fn> : *void` cast to opaque, ambiguous from cast alone).
  Regression at `examples/131-callconv-mismatch-diagnostic.sx`.
- **2026-05-25 (early)** — Implicit-Context refactor SHIPPED
  end-to-end. All 9 plan steps
  (`lets-see-options-for-merry-dijkstra.md`) landed. `context` is
  no longer an LLVM global; every sx function carries `__sx_ctx`
  at slot 0; `context.X` reads load through `current_ctx_ref`;
  `push Context.{...}` is alloca + rebind; FFI-inbound entries
  install `&__sx_default_context`; interp bootstraps the default
  Context on top-level call. 152/152 + unit tests green.
  Commits: `29784c2` (Steps 1-2), `92c6b47` (Step 3),
  `4bf5908` (Steps 5-7), `b69a2ea` (Step 8).
- **2026-05-24** — Phase 1.1 shipped: `buildProtocolValue` heap-copy
  now routes through `context.allocator.alloc` via the new
  `allocViaContext` helper. Regression at
  `examples/130-xx-value-routes-through-context-allocator.sx`
  proves a `Tracer` installed via `push Context` sees the alloc
  (`Tracer.count = 1`) — interp + codegen parity. 152/152 +
  chess green.
- **2026-05-24** — issue-0041 and issue-0042 both fixed end-to-end.
  Also removed the silent `.s64` fallback in `resolveTypeArg`,
  guarded the two upstream callers (`buildTypeBindings`,
  `inferGenericReturnType`) with `type_bridge.isTypeShapedAstNode`,
  and fixed three parser regressions introduced by the 0041 work
  (`[:0]u8` return type, nested return-arrows, `struct #compiler`
  trailing-`;` method decls). Full verify-step.sh gate green.
  CLAUDE.md REJECTED PATTERNS gained the silent-fallback-defaults
  prohibition. Stream now READY for Phase 1.
- **2026-05-24** — Phase 0.6 shipped (`align_of($T)` builtin).
  Touchpoints: `inst.zig` BuiltinId, `lower.zig` registry +
  return-type table + reflection handler, `interp.zig` fallback,
  `sema.zig` builtin allowlist, `lsp/server.zig` both completion
  tables, `library/modules/std.sx`. Smoke coverage added in
  `examples/50-smoke.sx`. 151/151 + chess green on all platforms.
  Then `size_of(*u8)` parse error was investigated — filed as
  issue-0041 (pre-existing, affects both `size_of` and `align_of`).
  Stream paused on 0041. Also tightened CLAUDE.md IMPASSIBLE RULES
  to close the "pre-existing / non-blocking" loophole that almost
  let this session roll past the issue filing.
- **2026-05-24** — issue-0040 filed. Phase 0.9 verified that
  `obj.method(Type)` with a `$T: Type` parameter fails to dispatch
  via dot, while explicit static (`T.method(obj, Type)`) and pipe
  (`obj |> T.method(Type)`) both work. Root cause pinpoint:
  `src/ir/lower.zig:5066-5123` has branches for generic-template
  struct methods (5082) and non-generic qualified (5106), but no
  branch for a non-template struct with a generic method. Stream
  paused on 0040.
- **2026-05-24** — Phase 0.8 `#foreign("c")` syntax verified.
  Form is `name :: <sig> #foreign libc ["c_name"]` with the optional
  string literal supplying a rename. Confirmed via
  `libc_strlen :: (s: *u8) -> usize #foreign libc "strlen";`
  scratch test (interp + codegen parity).
- **2026-05-24** — issue-0039 fix verified, full
  `tools/verify-step.sh` gate green again: 150/150 example tests
  pass and chess builds + screenshots OK on macOS / iOS sim /
  Android.
- **2026-05-24** — issue-0038 fix verified; spike now errors as
  expected on transitive references. 149/149 example tests pass
  (+1 vs pre-fix). Chess build broken as predicted — three-bucket
  triage written up in `issues/0039-chess-needs-explicit-imports-
  post-0038.md`. Stream paused on 0039.
- **2026-05-24** — Phase 0.7 spike at `/tmp/sx-import-spike/`
  (`a.sx → b.sx → c.sx`) showed `a.sx` calls `c_only_fn()` and reads
  `c_only_const` directly. Filed as issue-0038. Stream is paused per
  the IMPASSIBLE RULE — no workaround, the libc hide-by-internal-
  module strategy in the plan depends on the language semantics
  matching the assumption.
- **2026-05-24** — Phase 0.2 sanity sweep landed. Five additional xx
  cast patterns exercised through `tools/scratch.sh`; all show
  interp/codegen parity. Combined with the issue-0037 regression at
  `examples/126-xx-recover-then-dispatch.sx`, the cast story is now
  considered tight for the cases the MEM plan relies on.
- **2026-05-24** — Phase 0.3 chess allocator audit recorded above.
  No chess-side migration needed; ISSUE-MEM-002 (`context.allocator`
  bypass) is the only thing the chess codebase is exposed to and
  Phase 1 already owns it.
- **2026-05-24** — Phase 0.0a (`tools/verify-step.sh`) shipped.
  Confirmed working: 145/145 example tests + chess builds + screenshots
  on all 3 platforms. Initial 3-second screencap delay was too short
  for Android — increased to 6 seconds; iOS sim + macOS to 5 seconds.
- **2026-05-24** — Phase 0.0b (`tools/scratch.sh`) shipped. Verified
  with a hello-world snippet: interp + codegen agree.
- **2026-05-24** — Phase 0.0c initial implementation of
  `TrackingAllocator` in `library/modules/allocators.sx`. Build + 145
  tests pass after snapshot regen. Chess green on all 3 platforms.
  Manual scratch.sh test confirms counters increment correctly when
  called directly on the tracker variable.
- **2026-05-24** — ISSUE-MEM-007 fixed in `src/ir/lower.zig`.
  Root cause: `emitProtocolDispatch` keyed the auto-unbox path on
  `mi.ret_type == void_ptr`, but `*void` is overloaded — both
  Self-disguised-as-*void AND a literal `-> *void` return appear as
  the same `TypeId`. With `target_type` leaking from the enclosing
  function's return type (e.g. `main -> s32`), every `*void` return
  was loaded as `s32`, yielding 0 → null. Fix: stash `ret_is_self`
  on `ProtocolMethodInfo` during `registerProtocolDecl` (set when
  the AST return-type node is the `Self` type-expr), and gate the
  unbox on that flag. Regression at
  `examples/99-protocol-void-pointer-return.sx`. Sister symptom
  (SIGTRAP inside struct-static method storing an Allocator field)
  also fixed by the same change.
- **2026-05-24** — issue-0037 fixed in `src/ir/lower.zig`. Root
  cause: `lowerXX` had a Concrete→Protocol erasure branch but no
  inverse Protocol→pointer recovery — the cast fell through to
  `coerceToType`, which couldn't match the (struct, pointer) shape
  and returned the operand unchanged. Result: a 24-byte protocol
  struct stored into an 8-byte ptr alloca, corrupting adjacent
  stack (the protocol value's own slot was the next victim, so the
  next dispatch loaded garbage and crashed). Fix: when src is a
  protocol value and dst is a pointer, emit `struct_get` of field 0
  (ctx), then bitcast `*void` → dst. Regression at
  `examples/126-xx-recover-then-dispatch.sx`.

## Known issues (discovered during execution)

### ISSUE-MEM-001: Type inference defaults `p := malloc(64)` to `s64`

**Severity:** medium (workaround exists; bites unexpectedly).

**Symptom:** Writing `p := malloc(64)` (no explicit type) infers
`p: s64` instead of `p: *void`. Subsequent `free(p)` then fails LLVM
verification with "Call parameter type does not match function
signature!" because `free` expects `ptr` but receives `i64`.

**Workaround:** Explicit type annotation `p : *void = malloc(64);`
or `xx malloc(64);` at the call site.

**Reproduction:**
```sx
main :: () -> s32 {
    p := malloc(64);   // p inferred as s64
    free(p);            // LLVM verify fails: ptr expected, i64 given
    0;
}
```

**Root cause:** Likely in the inference path for `:=` declarations
when the RHS is a `*void`-returning #builtin. The compiler defaults
the binding to s64 instead of matching the return type. To
investigate in a future session.

**Status:** Open. Not blocking mem.sx work but worth fixing as a
quality-of-life issue. File as `examples/issue-NNNN.sx` when
addressed.

### ISSUE-MEM-002: `context.allocator.alloc/dealloc` bypasses protocol dispatch

**Severity:** high (breaks the entire Phase 1 premise; documented
fix in Phase 1).

**Symptom:** Any code that goes through `context.allocator.alloc(size)`
or `context.allocator.dealloc(ptr)` is pattern-matched in
[src/ir/lower.zig:5137-5159](src/ir/lower.zig#L5137-L5159) and lowered
directly to `.heap_alloc`/`.heap_free` IR — which calls libc
malloc/free. The protocol-value vtable is bypassed entirely.

This means a `push Context { allocator = my_tracker }` block
followed by `context.allocator.alloc(size)` does NOT call the
tracker's `alloc` method. The tracker sees zero allocations even
though many occurred.

**Workaround:** Call the allocator directly via a variable rather
than via `context.allocator`:
```sx
push Context.{ allocator = tracker, data = null } {
    p := tracker.alloc(64);     // works — dispatches through tracker
    tracker.dealloc(p);
}
```

But this defeats the purpose of context-allocator overriding for
user code that doesn't know about the tracker.

**Fix:** Phase 1 of the mem.sx plan removes this pattern-match and
replaces it with proper context dispatch through the Allocator
protocol. After Phase 1, `context.allocator.alloc(size)` correctly
dispatches to whatever allocator is currently set in context.

**Status:** Documented in plan; fixed in Phase 1. Blocks
auto-tracker-wrap (Phase 5 `--leak-check`).

### ISSUE-MEM-003: 08-types test depends on undefined memory contents

**Severity:** low (flaky test exposes itself when allocator code
changes).

**Symptom:** `examples/08-types.sx` declares a struct field
`c : u8 = ---;` (uninitialized) and prints the struct. The expected
snapshot captures a specific value (formerly `c: 176`, now `c: 8`)
which depends on whatever's in undefined memory at that moment. Any
allocator change shifts the value.

**Workaround:** Regenerate snapshot via `bash tests/run_examples.sh
--update` when this test fails for unrelated reasons.

**Fix:** Test should be rewritten to NOT depend on undefined memory
content — perhaps verify the field is one of N specific values, or
just don't print uninitialized data. Out of scope for mem.sx.

**Status:** Open. Document and live with it for now.

### ISSUE-MEM-004: Adding code to allocators.sx shifts JNI/Obj-C IR snapshots

**Severity:** medium (eats time per step).

**Symptom:** Every additive change to allocators.sx (new struct,
new method) cascades into ~11 IR snapshot diffs across the
`tests/expected/ffi-{jni,objc}-*.ir` files. Each step needs
`--update` + `git diff` review. The diffs are usually benign
(additive declarations) but one (`ffi-objc-call-06-sret-return.ir`)
reorganises ~1500 lines because it uses reflection on the full type
registry.

**Workaround:** Per-step `--update` + diff review.

**Fix:** Phase 0.1 spike — extend `normalize_ir()` in
`tests/run_examples.sh` to strip allocator-related declarations and
constant-pool renumberings from snapshots. Should make additive
changes invisible at the snapshot level while preserving JNI/Obj-C
ceremony signal.

**Status:** Mitigated; structural fix in Phase 0.1.

### ISSUE-MEM-005: Two-line `create(@storage)` pattern for allocators

**Severity:** low (cosmetic but real DX friction).

**Symptom:** Current pattern requires a separate storage decl + a
create call:
```sx
g_gpa : GPA = ---;
libc := GPA.create(@g_gpa);
```

Two lines per allocator. Plan committed to one-line via heap-copy:
```sx
libc := GPA.create();   // heap-copies via xx value
```

**Fix in progress:** Phase 0.0c — switch `create` methods on at
least TrackingAllocator (and possibly GPA/Arena/BufAlloc) to use
`xx value` heap-copy. Add `instance(a) -> *T` accessor for types
where users need the underlying state (TrackingAllocator).

**Status:** In progress (active work).

### ISSUE-MEM-007: Protocol dispatch on `*void`-returning methods returns null (FIXED)

**Severity:** was CRITICAL; resolved.

**Root cause:** `emitProtocolDispatch` in `src/ir/lower.zig` gated
its auto-unbox path on `mi.ret_type == void_ptr`, but the same
`TypeId` covers both Self-disguised-as-*void and a literal
`-> *void`. With `target_type` leaking from the surrounding
function (e.g. `main -> s32`), every protocol call returning
`*void` got its result loaded as `sizeof(target_type)` bytes — for
`s32` that's the first 4 bytes of the malloc'd block, which were
zero, comparing equal to null.

**Fix:** Tag `ProtocolMethodInfo` with `ret_is_self: bool`, set in
`registerProtocolDecl` when the AST return-type is the `Self`
type-expr. `emitProtocolDispatch` only takes the auto-unbox path
when `ret_is_self` is true. Literal `*void` returns are now passed
through unchanged.

**Regression:** `examples/99-protocol-void-pointer-return.sx`. The
sister symptom (SIGTRAP from protocol dispatch inside a struct
static method that stores an Allocator field) was the same root
cause and is also fixed.

**Status:** Resolved 2026-05-24.

### ISSUE-MEM-006: Android screencap needs 6+ seconds; iOS sim + macOS 5+

**Severity:** low (fixed in tooling).

**Symptom:** Initial `verify-step.sh` used `sleep 3` before
screencap. Android needed longer for the side panel to render;
without it, the screenshot showed only the chess board and a black
strip where the side panel should be.

**Fix:** Updated `verify-step.sh` delays: macOS 5s, iOS sim 5s,
Android 6s. Documented inline in the script.

**Status:** Resolved.