Parser hard-rejects the legacy `name: ..T` form with a one-line
migration message pointing at the new `..name: []T` shape. The
leading-`..` form is the one the lowering paths
(`resolveParamType` / `packVariadicCallArgs`) treat as canonical
post-issue-0049; leaving both forms accepted invited the same
class of cross-module emit crashes any time a `..T`-form decl in
stdlib crossed an import boundary.
`specs.md` updated alongside: the Variadic Functions section now
documents `..name: []T` as the surface form, with notes on
homogeneous vs `[]Any` boxing and the `..` spread at call sites.
Inline references to `args: ..Any` in §7 and §8 refreshed.
`xx <struct-typed local>` used to heap-copy the value through context.allocator.
The protocol value's `ctx` pointed at the heap copy; the original local was
left behind, untouched. Mutations through the protocol never reached the
original, and direct reads of the original never saw protocol mutations.
Two-fork bug, silent, easy to write by mistake.
New rule (Option 3 in the discussion):
- `xx <lvalue>` — identifier, field access, index expression, deref —
borrows the operand's storage. No heap copy, no `free` needed.
- `xx <rvalue>` — struct literal, function-call result, arithmetic, etc. —
heap-copies through context.allocator. Unchanged from today.
- `xx @ptr` and `xx <pointer-typed value>` — borrows the pointee. Unchanged.
Single switch in `buildProtocolErasure` ([lower.zig:10334](src/ir/lower.zig#L10334))
gated by a new `isLvalueExpr` helper ([lower.zig:10322](src/ir/lower.zig#L10322)).
Struct-typed operand: if the AST shape is identifier/field/index/deref,
emit `lowerExprAsPtr(operand_node)` and skip the heap-copy; otherwise
keep the alloca-store-heap_copy path.
specs.md §3 ownership table extended to three rows (rvalue, lvalue,
pointer) with examples and rationale per row.
Regressions:
- `examples/130-xx-value-routes-through-context-allocator.sx` — the
Phase 1.1 witness for heap-copy-via-context-allocator. Previous shape
(`xx <local-value>`) is now a borrow under Option 3 and no longer
exercises the heap-copy path. Rewritten to use a struct literal
(`xx ByValue.{...}`) which still heap-copies through context.allocator
— Tracer.count = 1 as before.
- `examples/135-xx-lvalue-borrows.sx` — new test. Dereferences a
TrackingAllocator into a stack value, does `xx tracker` inside a
push Context, and asserts alloc_count/dealloc_count on the LOCAL go
up. Under old semantics this would have stayed at 0 (heap copy got
the increments, local stayed stale).
157/157 example tests pass; chess clean on macOS / iOS sim / Android
(`tools/verify-step.sh` ran green immediately before this work).
The chess panel-text regression (text vanished after the first move on
macOS) had a single root cause: GlyphCache's entries List, hash table,
and shaped_buf grew through `context.allocator` — which during render
is the per-frame arena. On the next arena reset the backing died, and
subsequent glyph lookups read garbage / wrote into freshly-allocated
view-tree memory.
Fix is shaped as the user proposed: `List(T)`'s mutations take an
optional trailing `alloc: Allocator = context.allocator` argument. No
allocator stored on the container, no init ceremony, every existing
`list.append(item)` callsite keeps working unchanged. Long-lived
owners now write `list.append(item, self.parent_allocator)` and the
arena-leak bug becomes impossible to write accidentally.
Default-arg substitution previously only fired for identifier callees
(`expandCallDefaults` at lower.zig:7978). Extended to the generic
struct-method dispatch path (`list.append(...)` lands here) via a new
`appendDefaultArgs` helper that lowers fd.params[i].default_expr in
the caller's scope and appends to the lowered args slice.
Long-lived owners updated to capture `parent_allocator: Allocator` at
init and use it for every internal growth:
- GlyphCache (the chess bug) — entries, shaped_buf, hash_keys,
hash_vals, atlas bitmap.
- DockInteraction — drops the existing `push Context` workaround in
`ensure_capacity` for the explicit-arg form.
- StateStore — entries list + per-entry data buffer.
- Gles3Gpu, MetalGPU — shaders, buffers, textures (atlas-grow during
render would otherwise leak resources into the frame arena).
Also kept: an operator-precedence fix in pipeline.sx
(`(self.frame_index & 1) == 0` instead of
`self.frame_index & 1 == 0`, which parses as
`self.frame_index & (1 == 0)` = always 0). That was a stealth
single-arena-only bug that masked the GlyphCache one for a long time.
Docs:
- specs.md §11 documents `param: T = expr` default parameter values.
The parser already supported it — formalised in the spec now.
- current/CHECKPOINT-MEM.md logs the change.
- CLAUDE.md REJECTED PATTERNS gains a "Long-lived containers growing
through context.allocator" section with the `parent_allocator`
capture template and the list of existing examples to mirror.
155/155 example tests pass — zero-diff against snapshots since every
existing callsite still resolves to `context.allocator`.
