Language-Surgery Audit Checklist

Run this after any commit that changes compiler passes, SSA flags, lowering transforms, or runtime conventions. Not exhaustive — a ready-made "suspect this first" list for weird behavior.

The meta-pattern: TinyGo set SSA flags intending to replace a subsystem with its own emission. Every such flag is a fork in the road where the surgery might have taken only one path. Moxie added more forks.

The ten-minute sweep

1. Init chain emission

• [ ] ssa.BareInits set? Then every backend must emit its own

cross-package init chain. Verify each backend's generated entry point iterates packages in dep order and calls pkg.init() for each.

• [ ] Regression test: a package-level var x = f() where f is in another

package. Confirm x is set before main runs.

• [ ] Check: builder/build.go runtime.initAll construction (~line 524).

2. Anonymous functions / closures

• [ ] SSA flags BuildSerially or NaiveForm set? If yes, SSA skips

automatic closure lifting — backends must handle FreeVars manually.

• [ ] Test: a closure capturing two distinct types; call through a

func() value after the constructor returns.

• [ ] Check: compiler/func.go:parseMakeClosure.

3. Interface method tables

• [ ] Empty interface (any, interface{}) method invoke path — does it

reach getMethodsString with zero methods? That yields empty signature strings and NPE in transform/interface-lowering.go.

• [ ] Type assertions on empty interface handled separately from

non-empty case?

• [ ] Test: var x any = concreteVal; _ = x.(Method) should not crash

the compiler.

• [ ] Check: compiler/interface.go, transform/interface-lowering.go.

4. Reflect elimination

• [ ] Any stdlib package depend on reflect? If so, it must be stubbed

in src/ or removed.

• [ ] errors.As gone? errors.Is uses only type assertions?
• [ ] No silent "compiles but panics at runtime" path — missing reflect

must error at link time.

• [ ] Check: src/errors/wrap.mx, mxtext/rewrite.go exemption list.

5. Intra-package var order

• [ ] types.Info.InitOrder is still authoritative (it is — checker-level,

not backend-level). BareInits does not touch this.

• [ ] Test: var b = a + 1; var a = 5 — both backends must init a first.
• [ ] Check: vendor/.../ssa/builder.go:3238-3273 (outside BareInits guard).

6. Spawn static analysis

• [ ] Runs on pre-lowered SSA — confirm by checking it happens inside

CompilePackage before OptimizePackage.

• [ ] Move semantics: does it track cross-block uses of spawned args?

Currently does not (restrict.go:checkSpawnMoveRestriction only walks same-block forward). If the surgery extends to flow analysis, verify dominator-tree traversal.

• [ ] Codec enforcement: if the moxie package isn't imported, spawn

silently skips Codec checks. Should be a hard error.

• [ ] Test: x := foo(); spawn(worker, x); if cond { use(x) } — the

if-branch use is currently not flagged.

• [ ] Check: compiler/spawn.go, compiler/restrict.go.

7. Goroutine / scheduler

• [ ] go f() in user code rejected at SSA? Exemption list in

restrict.go:isUserPackage still accurate (runtime*, internal/*, os, syscall, unsafe)?

• [ ] coro.mx still needed only for iter package?
• [ ] Scheduler config ("tasks"/"asyncify"/"none") — is anything

other than "none" reachable? If not, strip the branches.

• [ ] Check: compiler/compiler.go:1524-1530, compiler/goroutine.go.

8. Defer chains

• [ ] Loop-detected defers use heap allocation? Tarjan SCC still runs?
• [ ] Closure-in-defer: captured vars reach deferred call correctly?
• [ ] Panic path: landing-pad in LLVM.
• [ ] Check: compiler/defer.go.

9. SSA pass ordering

• [ ] Any pass assuming "entire program's SSA is built"? Verify it runs

after Build() - not inside CompilePackage.

10. Generated-output smoke

• [ ] Regenerate one small test program for native target.

Diff the entry point / init-chain structure against a known-good baseline.

• [ ] Run tests/ end-to-end.

When to run

• After any change to compiler/, transform/, builder/.
• After bumping vendor/golang.org/x/tools/.
• Before release tags.
• When a user reports behavior that only reproduces on one target.

When a check fires

Don't patch symptoms. Trace back to whether the underlying assumption (SSA flag, pass order, backend responsibility) is what it should be. The bug is usually a seam between TinyGo's assumptions and Moxie's surgery, not a single wrong line.