fix(checker): reject private types in public APIs

[akonwi]

Summary

• validate each module's public interface after checking completes
• reject private nominal types exposed through fields, signatures, aliases, unions, traits, methods, inferred globals, wrappers, or generic arguments
• stop at public nominal boundaries so each owning module validates its own declarations
• add deterministic structured diagnostics and cross-module regression coverage
• document that public APIs cannot expose private types

Problem

The checker previously accepted public APIs containing private types. Generated Go then failed when another module needed to name the corresponding unexported Go type, so ard check and ard build disagreed.

Migration

Make leaked types public or keep them entirely within private declarations. Dram and Maestro have already been updated to comply with this rule.

Validation

• cd compiler && go test ./... -count=1
• cd website && npm run build
• gopls check on touched Go files; only pre-existing redundant-break hints
• git diff --check
• compiler examples check successfully
• Decode: 9 tests passed
• SQL: 6 tests passed
• Migrate: 38 tests passed
• Tinear: 36 tests passed
• Dram: 32 tests passed; check and example build passed
• Maestro: dependencies verified, 46 tests passed, check and build passed

Fixes #337

[vercel]

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Project	Deployment	Actions	Updated (UTC)
ard-lang-dev	Ready	Preview, Comment	Jul 25, 2026 4:31am