#[debug_visualizer] seems like it will be very useful.

One of the current issues with Rust (and a place where C++ is still better) is debugging. Granted, I end up needing to debug Rust code much less often than C++ code, but it would still be nice to actually call rust functions in IntelliJ (and it seems there's limited support in gdb and lldb), and view data-structures like maps opaquely instead of just their complex internals.

I feel that Rust could really profit from an interactive REPL like notebook like Julias Pluto. It makes visualisations during development and their integration with documentation so seamless.