It's pretty hard to do well. If you look at Graal, a lot of the cutting edge research work they've done is about how to do cross-language inlining and subsequen

It's pretty hard to do well. If you look at Graal, a lot of the cutting edge research work they've done is about how to do cross-language inlining and subsequent optimisations better. It's more of a function of the JIT compiler design than language or bytecode specs though.