lyng/docs/ai_notes_wasm_generation_bug.md

AI notes: avoid Kotlin/Wasm invalid IR with suspend lambdas

Do

• Prefer explicit object : Statement() with override suspend fun execute(...) when building compiler statements.
• Keep Statement objects non-lambda, especially in compiler hot paths like parsing/var declarations.
• If you need conditional behavior, return early in execute instead of wrapping parseExpression() with statement(...) { ... }.
• When wasmJs tests hang in the browser, first check wasmJsNodeTest for a compile error; hangs often mean module instantiation failed.

Don't

• Do not create suspend lambdas inside Statement factories (statement { ... }) for wasm targets.
• Do not "fix" hangs by increasing browser timeouts; it masks invalid wasm generation.

Debugging tips

• Look for $invokeCOROUTINE$ in wasm function names when mapping failures.
• If node test logs a wasm compile error, the browser hang is likely the same root cause.