[guettonenrique]

Summary

Fixes a fatal Android compilation error when building Nitro Hybrid Views with Kotlin 2.4+.

Problem

Under Kotlin 2.4.0 (KTLC-365: "Prohibit always-false is checks for definitely incompatible types"), statically impossible is checks between final classes and unrelated interfaces were upgraded from compiler warnings to fatal compilation errors.

When a Kotlin HybridView implementation class does not implement RecyclableView, Nitrogen's generated ViewManager contains:

@Suppress("USELESS_IS_CHECK")
if (hybridView is RecyclableView) { ... }

Because hybridView is a final class that doesn't implement RecyclableView, this fails compilation on Kotlin 2.4+ with:

Check for instance is always 'false'.

Because this is now a fatal compilation error in Kotlin 2.4, @Suppress("USELESS_IS_CHECK") can no longer suppress it.

Solution

• Upcast hybridView through Any first (val recyclableView = (hybridView as Any) as? RecyclableView). This satisfies Kotlin 2.4's static type checker while remaining fully compatible with earlier Kotlin versions and preserving exact runtime semantics.
• Called bun specs to regenerate and update the committed test fixture bindings in tests/react-native/.

Test plan

1. Monorepo Build & Typecheck

• Ran: bun run build and bun typecheck
  • Result: Both completed with exit code 0 across all workspaces.

2. Nitrogen Output Verification

• Ran: bun specs
  • Result: Successfully regenerated all Nitrogen bindings and updated tests/react-native/ test fixtures with no unexpected diffs.

3. Real-World Android Build

• Ran: Android build on an Expo SDK 58 project with Kotlin 2.4.0.
  • Result: View managers compiled and assembled cleanly (BUILD SUCCESSFUL), eliminating the fatal Check for instance is always 'false' error.

Checklist

• Ran bun run build and bun typecheck
• Ran bun specs and committed all generated fixture updates

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1 Skipped Deployment

Project	Deployment	Actions	Updated
nitro-docs	Skipped		Oct 25, 2026 11:49am UTC