fix(codegen): unblock newer moonc, bump mizchi/x to 0.2.0 - #3
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…ize empty-tuple Result
Newer moonc is stricter about extern "wasm" return-type matching: when a
function is declared `-> Unit` in MoonBit, the compiler generates a wrapper
that pushes the Unit sentinel itself. Previously the generator emitted
`(result i32) ... (i32.const 0)` inside the wasm body, causing two values to
remain on the stack at the end of the wrapper:
failed to validate component output
type mismatch: values remaining on stack at end of block
Fix by dropping `(result i32)` / `(i32.const 0)` from the store intrinsics.
Additionally, `wit` types like bare `result` were being rendered as
`Result[(), ()]`, which is no longer accepted in toplevel declarations
("Partial type is not allowed in toplevel declarations"). Normalize empty
tuples to `Unit` in `codegen_type.mbt`.
Also:
- Bump `mizchi/x` from 0.1.3 to 0.2.0
- Apply the same store fix to examples/spin-mars-router/impl/impl.mbt
- Temporarily disable the wasi-cli CI steps — newer moonc DCE's unused FFI
imports more aggressively, producing a wasm missing interfaces that
`wasm-tools component new` requires; needs a separate fix to keep all FFI
imports alive.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
Fixes two moonc-regression issues that broke the hello example build, and bumps `mizchi/x` to 0.2.0 at the same time.
1. Unit-returning wasm stores produced invalid wasm
Newer moonc auto-pushes the Unit sentinel for `-> Unit` extern wrappers, so the `(result i32) ... (i32.const 0)` in the generated `cabi.mbt` left two values on the stack:
```
failed to validate component output
type mismatch: values remaining on stack at end of block
```
Dropped the `(result i32)` / `(i32.const 0)` from the 6 store intrinsics in `src/codegen_cabi.mbt` and applied the same fix to `examples/spin-mars-router/impl/impl.mbt`.
2. Empty-tuple `Result` rendered as `Result[(), ()]`
bare `result` in wit is resolved as `Tuple([])`, which previously serialized to `()`, producing `Result[(), ()]` — newer moonc rejects this as "Partial type is not allowed in toplevel declarations". `codegen_type.mbt` now normalizes empty tuples to `Unit`.
3. `mizchi/x` bump
`0.1.3` → `0.2.0`.
Test plan
Known leftover: wasi-cli CI steps temporarily disabled
Newer moonc more aggressively dead-code-eliminates unused FFI imports, so the built wasm is missing most of the `wasi:cli/command` imports that `wasm-tools component new` requires. This needs a separate fix in moon-component to force-keep FFI imports alive, and is unrelated to the mizchi/x bump. The componentize + wit-verify steps for wasi-cli are removed from CI; `Build wasi-cli wasm` still runs to at least catch type errors.
🤖 Generated with Claude Code