Comment by sklogic

In my experience such languages are very dangerous and it is better to have a chain of more restrictive languages instead. Most passes only make sense in a fixed sequence anyway. LLVM is infanously broken in this regard, btw., there are too many implicit pass dependencies.

E.g., there is no point in keeping a one-handed 'if' in a language after a pass which lowers it into a two-handed 'if'. There is no point in keeping a 'lambda' node in your AST after lambda lifting is done.