If you have compiler-crashing problems, like this:...

# webassembly

[AndrewStone]

If you have compiler-crashing problems, like this:

java.lang.NullPointerException: null cannot be cast to non-null type org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol

This slack convo solved them for me: https://slack-chats.kotlinlang.org/t/27045384/hi-there-i-have-a-very-annoying-internal-compiler-error-here#0a1d5745-d31d-4c97-9a1d-92cabe33fe88
Basically, put mavenLocal() at the end of your repo source list, and delete ~/.m2 -- your machine has cached old libs. I'm repeating it here because the visibility of this solve is low, and this problem hit me moving up to 2.2.20.