I have been keeping a local copy of the Kotlin Interactive Shell and updating the Kotlin version. It has worked well up to Kotlin 1.9.10, but after upgrading the source to use 1.9.20, I get the following error:

$ ki
ki-shell 0.5.2-KK2/1.9.20
type :h for help
[0] import java.math.BigDecimal
[1] import java.math.BigInteger
ERROR Backend Internal error: Exception during psi2ir
File being compiled: Line_2.kts
The root cause java.lang.IllegalStateException was thrown at: org.jetbrains.kotlin.ir.util.SymbolTableSlice$Scoped.noScope(SymbolTableSlice.kt:173) (Line_2.kts): org.jetbrains.kotlin.backend.common.BackendException: Backend Internal error: Exception during psi2ir
File being compiled: Line_2.kts
The root cause java.lang.IllegalStateException was thrown at: org.jetbrains.kotlin.ir.util.SymbolTableSlice$Scoped.noScope(SymbolTableSlice.kt:173)
[2]

Any idea what's changed in 1.9.20 to cause this?

No ideas at first glance. Could you please create an issue in the Kotlin YT and post it here? I haven't tried to migrate ki to the newest kotlin yet.

Thanks, Ilya, I've created https://youtrack.jetbrains.com/issue/KT-63158/Kotlin-version-1.9.20-breaks-Kotlin-Interactive-Shell

Thanks! I'll have a look.