This proof-of-concept demonstrates how Rust macros can be abused to interact with the machine that the compliation happens on. When the do_not_compile_this_code is opened in VS Code with the rust-analyzer plugin, the editor expands the some_macro!() macro. This macro reads then content of ~/.ssh/id_rsa_do_not_try_this_at_home and deletes the file. This behavior also occurs when cargo build is run or when the application is run.
The key insight is that Rust macros are expanded before/during compilation, i.e. arbitrary code execution during compilation. This is a demostration that this is a huge vulnerability in the rust ecosystem that needs to be taken seriosly.