docs(metatype): issue 0140 resolved; make_enum unblocked

current/CHECKPOINT-METATYPE.md

@@ -74,15 +74,17 @@ in the always-loaded prelude interns them into every module's type table and
 shifts every `.ir` snapshot. On-demand import keeps the prelude clean.
 
 ## Next step
-**BLOCKED on issue 0140** for the make_enum path (see Known issues). The other
-two are unblocked:
+Pick any (independent):
 - **`make_enum(variants: []EnumVariant)`** sx helper over a COMPUTED (non-literal)
-  variant list — exercises the interpreter decoding a value-arg slice in `define`
-  (vs. the literal `.[ … ]` the current examples use). **BLOCKED:** a computed
-  (pointer-backed) `[]EnumVariant` slice from a local var / `List` does not decode
-  in `defineEnum`/`decodeVariantElements`, and the resulting interp bail is
-  SWALLOWED (panic / misleading cascade, no root reason) — issue 0140. Fix 0140
-  first so the decode failure surfaces cleanly, THEN implement the slice decode.
+  variant list — exercises the interpreter decoding a value-arg slice in `define`.
+  **UNBLOCKED** (issue 0140 fixed — decode failures now surface a clean diagnostic
+  at the construction site instead of a panic/cascade). Remaining work: a computed
+  (pointer-backed) `[]EnumVariant` slice from a local var / `List` still does not
+  DECODE in `defineEnum`/`decodeVariantElements` — that decoder needs to follow a
+  `slot_ptr`/`heap_ptr` data field (today it only reads an inline `.aggregate`).
+  Probes: `.sx-tmp/probe_me2.sx` (sliced local array → bail "TypeError"),
+  `.sx-tmp/probe_makeenum.sx` (List → bail "struct_get: base has no fields"); the
+  inline-literal-param form already works (`.sx-tmp/probe_me3.sx`).
 - **Widen `type_info` / `TypeInfo` past `` `enum ``** — struct/tuple variants:
   add `` .`struct ``/`` .`tuple `` to the `TypeInfo` enum in `meta.sx`, teach
   `reflectTypeInfo` to build them, and teach `defineEnum` (→ a `defineType`) to
@@ -92,19 +94,24 @@ two are unblocked:
   self-reference already rejected — issue 0139.)
 
 ## Known issues
-- **issue 0140 (OPEN) — a failing comptime type construction panics instead of
-  diagnosing.** `evalComptimeType` (`comptime.zig:~457`) swallows the interp's
-  `last_bail_detail` via `catch return null`; callers poison to `.unresolved`
-  with no diagnostic, and `.unresolved` reaches LLVM emission → panic ("unresolved
-  type reached LLVM emission"), or rides behind a misleading downstream cascade.
-  Pre-existing (plain `define` path; surfaced while starting make_enum). Repro:
-  `issues/0140-*.sx`. Blocks the make_enum computed-slice step. **Session paused
-  pending the fix** per the CLAUDE.md IMPASSABLE rule.
+- issue 0140 — comptime type-construction bail panicked instead of diagnosing —
+  RESOLVED. `evalComptimeType` now clears `last_bail_detail` before the interp
+  call and, on the `catch`, emits a build-gating `.err` at the construction span
+  ("comptime type construction failed: {detail}") before returning the
+  `.unresolved` poison — so the reason is shown and no unresolved type reaches
+  emission unannounced. `examples/1179` locks it.
 - issue 0139 — by-value self-reference segfault — RESOLVED (`checkInfiniteSize`
   Pass 1g emits a loud "infinitely sized" diagnostic + breaks the cycle;
   `examples/1178` locks it).
 
 ## Log
+- **issue 0140 fixed.** A comptime type-construction bail (`declare`/`define`/
+  reflection) used to panic at LLVM emission ("unresolved type reached LLVM
+  emission") or hide behind a cascade — `evalComptimeType` swallowed the interp's
+  `last_bail_detail`. Now it clears the detail before the call and renders a
+  build-gating `.err` at the construction span on the `catch`. `examples/1179`
+  locks the empty-variants case. Suite green (677). Unblocks make_enum (its
+  computed-slice decode failures now surface cleanly).
 - **`type_info($T)` reflection done (enum round-trip).** New `BuiltinId.type_info`;
   `lower/call.zig` resolves `$T`, rejects non-enum loudly, emits the builtin;
   `interp.zig:reflectTypeInfo` constructs the exact nested-aggregate Value