The 0141 repro relied on a silent-wrong coercion: passing List.items (a
[*]T many-pointer, no length) to a []T parameter passed the bare 8-byte
pointer into a 16-byte {ptr,len} slot — garbage .len, at comptime a segfault
in the VM slice decoder (decodeMemberSlice), at runtime an LLVM verify failure.
Fix (root cause): classify [*]T -> []T as many_to_slice_reject in
conversions.zig and emit a build-gating diagnostic in coerce.zig telling the
user to slice with a length (ptr[0..len]). Guard runComptimeTypeFunc to skip
VM eval once diagnostics.hasErrors() — a type-fn body that failed coercion
holds malformed comptime data (a real host Addr) that would fault the VM's
Ref-level guards.
Land the corrected feature as examples/0640 (List-grown comptime enum via
vs.items[0..vs.len] -> green=7) and the rejection as
examples/1183-diagnostics-many-pointer-to-slice-rejected. Mark issue 0141
RESOLVED.
708/0 corpus + 476/476 unit.
cstring is ONE pointer to a null-terminated u8 buffer, C's char*: thin
(8 bytes, no length; cstring_len walks to the terminator), crossing
#foreign boundaries verbatim in both directions, with ?cstring as the
nullable case lowering to the same bare pointer (null = absent).
Conversion discipline mirrors Odin: a string LITERAL coerces implicitly
(its bytes are terminated constants); any other string is rejected with
a diagnostic naming to_cstring (it may be an unterminated view); and
cstring never coerces to string implicitly — from_cstring(c) is the
explicit zero-copy view, pricing the strlen.
Plumbing: TypeId/TypeInfo builtin slot 18 (first_user 19), name
classifiers, size/align/name tables, LLVM ptr lowering, the ?T pointer
niche, the xx pointer ladder, the literal-gated coercion plan
(isConstString + data_ptr), and the reserved-spelling set. std gains
cstring_len/from_cstring/to_cstring (fmt.sx, re-exported); the old
cstring(size) allocator helper is renamed alloc_string everywhere;
getenv migrates to (name: cstring) -> ?cstring as the canonical user
and env() drops its manual strlen/memcpy.
Pinned: examples/1222 (FFI both directions, literal coercion,
?cstring null paths, round trip) and examples/1173 (both coercion
diagnostics); FAIL pre-feature. The alloc_string rename + getenv
signature shift the .ir snapshots — regenerated. zig build test
426/426; run_examples 604/604.
Spec: reserved spelling + cstring section + C-interop rows.
Two silent-miscompile codegen fixes:
0083 — named-const array dimension. `TypeResolver.resolveCompound`'s array
arm resolved the dimension with `if int_literal ... else 0`, so a named const
(`N :: 16; [N]T`) hit the silent `else 0`: the array became 0-length / 0-byte
and element access ran out of bounds (garbage for scalars, bus error for
slice/pointer/struct elements). The arm now delegates the dimension to
`inner.resolveArrayLen` (symmetric with `inner.resolveInner` for the element).
The stateful `Lowering.resolveArrayLen` evaluates it as a compile-time integer
across the comptime-constant / generic-value / module-global const tables and
emits a diagnostic — no fabricated length — when it isn't one.
0084 — `.[...]` literal passed directly as a call arg. `lowerArrayLiteral`
always yields an aggregate array value; the array→slice conversion is the
caller's job. The local-bound var-decl path did it, but the call-arg coercion
path had no array→slice arm, so `classify([N]T, []T)` returned `.none` and the
raw array was passed where a slice was expected (callee read its {ptr,len}
header off the wrong bytes → 0 / garbage / segfault). `classify` now returns a
new `.array_to_slice` plan for same-element `[N]T → []T`, and `coerceToType`
emits the existing `array_to_slice` op — identical to the local-bound path.
Regressions (fail-before/pass-after demonstrated on the pre-fix compiler):
examples/0140-types-named-const-array-dim.sx (s64 + string + struct elems)
examples/0141-types-slice-literal-direct-call-arg.sx (string + []s64)
Gate: zig build, zig build test, bash tests/run_examples.sh (387 passed).
Issues 0083 and 0084 marked RESOLVED.
Coercion classification now lives in src/ir/conversions.zig behind a *Lowering
facade (CoercionResolver), mirroring CallResolver / GenericResolver /
ProtocolResolver. Two pure classifiers:
- classify(src, dst) -> CoercionPlan (15 kinds: no_op / unbox_any / box_any /
closure_to_fn_reject / tuple_elementwise / optional_unwrap / void_to_optional /
optional_wrap / erase_protocol / int_to_float / float_to_int / ptr_int_bitcast /
widen / narrow / none) — the built-in coercion ladder.
- classifyXX(src, dst) -> XXPlan (unbox_any / no_op / erase_protocol /
protocol_to_pointer / coerce) — the xx-operator head.
coerceToType and lowerXX now `switch (classify…)` then emit; branch order
mirrors the originals exactly and every arm reproduces the prior lowering — the
f32/f64 Any match dispatch, buildProtocolErasure (lowerXX) vs buildProtocolValue
(coerceToType), tuple/optional recursion, and the user-Into fallback + pointer
materialization + recursion-guard/diagnostics (which stay in lowerXX /
tryUserConversion). IR emission stays entirely in Lowering; the classifiers are
pure. lowerXX keeps the operand's lowered Ref type as src_ty. `.none` means no
built-in applies (pass through; the Into fallback runs) — no silent default.
New pub: isFloat / isIntEx / typeBitsEx / resolveConcreteTypeName (the classifier
reads them); coercionResolver() accessor. lower.zig net -54 lines.
conversions.test.zig drives CoercionResolver directly: the full classify ladder
(no-op, Any box/unbox, widen/narrow, int<->float, ptr<->int, optional
wrap/unwrap, void->optional, tuple, closure-reject, .none for two unrelated
structs), erase_protocol for a concrete source, and classifyXX (all 5 kinds incl.
protocol-to-pointer vs coerce and pointer-materialization -> coerce).
zig build, zig build test, tests/run_examples.sh (357/0) all green — no .ir churn.
