It not only informs the architecture but also the language design. For IDEs you want quick response even if it is not perfect, for a compiler you want correctne

It not only informs the architecture but also the language design. For IDEs you want quick response even if it is not perfect, for a compiler you want correctness over everything else. The language having syntactic redundancy can help an IDE parser recover gracefully from a typo or missing tokens. Having semantic negative space can let an IDE recognize intent for code that looks correct from extrapolated understanding that is actually not semantically correct, and suggest solutions. rustc already tries to do all of these strategies, but blows the latency budget because it still prioritizes correctness over everything else.