Not really, rust is unusable for interactive programming because of this reason. I understand that's not rust target domain but still there's downsides to be had with their approach.
Can’t speak to its quality, but there’s nothing stopping someone from writing a repl from a sufficient compiler API... and “good” is only limited by inference quality and runtime performance. IDEs are pretty snappy at showing you autocomplete as you type regardless of whether the language has a garbage collector. And performance - well, that’s what caching would be for, and an optimized compiler design that only needs to recompile changed code...
I would also point out the “auto” keyword in CPP likely saves folks a lot of typing ;-) I know it and similar inferences changed my mind on the whole static vs dynamic debate...
I'm not sure I understand, could you elaborate more?