Fix constraint solver non-determinism and test isolation#28
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Add missing grammar rule for (params) -> () in function type expressions.
The parser handled () -> () but not (self: T) -> () or (a: number) -> (),
causing parse errors in record field type annotations with void-returning
methods.
One new rule in parser.go.y:
'(' funcparamlist ')' TArrow '(' ')' → FunctionTypeExpr with empty Returns
Impact on real-world fixture scorecard (117 → 72 tracked errors):
- factory-constructor: 6 → 0 (fixed)
- iterator-pipeline: 11 → 0 (fixed)
- module-with-generics: 5 → 0 (fixed)
- service-locator: 14 → 0 (fixed)
- generic-registry: 12 → 4
- metatable-oop: 5 → 4
Two independent bugs causing test non-determinism: 1. types/flow/domain/type_domain.go: applyIsNil was unconditionally setting narrowed type to nil without checking if the base type could actually be nil. When a contradictory isNil constraint applied to a non-optional type, it corrupted the domain state instead of marking it unsatisfiable. Now filters by kind.Nil and marks Unsat when narrowing produces Never. 2. state_test.go: TestUninitializedVarAccess requires an exact 128-slot registry to trigger the resize at the right point. Previous drain of statePool was insufficient — per-P caches in sync.Pool could return states after the drain. Added runtime.GC() between drain passes to flush per-P caches. Verified: 0 failures in 50 consecutive runs of go test -count=1 .
Add M.TypeName = TypeName exports for all cross-file type declarations. While the checker resolves types through manifests (not runtime values), exporting types is idiomatic and enables runtime validation via :is().
When an identifier resolves to unknown through normal flow analysis but
matches a declared type name in scope, produce a Meta type wrapping
the declared type. This enables type values to flow through module
exports as first-class values.
Example: type Config = {host: string}; return {Config = Config}
Previously the Config field was unknown. Now it's typeof(Config),
enabling cross-module patterns like mylib.Config:is(data).
This matches the pattern used in wippy production code where type
declarations are exported as table fields for runtime validation.
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Summary
Root cause
applyIsNilin the constraint solver's type domain unconditionally set the narrowed type tonilwithout checking if the base type could actually be nil. When a contradictoryisNilconstraint was applied to a non-optional type (e.g., after truthiness narrowing), it corrupted the domain state instead of marking it unsatisfiable. This caused non-deterministic narrowing results depending on constraint evaluation order.Changes
types/flow/domain/type_domain.go:applyIsNilnow filters base type bykind.Niland marks domain unsatisfiable when narrowing producesNevertypes/constraint/solver.go: Propagate unsat from domain applicationstate_test.go: Drain pool + GC flush for registry-capacity-sensitive testtestdata/fixtures/realworld/: Export cross-file types asM.Type = TypeTest plan
go test -count=1 .go test -count=1 ./...— all packages passTestFixtureOrder_GenericRegistryThenMultiReturnregression testtype_domain_test.goandsolver_test.go