[scoutt]

Any multi-instance, multithread-capable language must have an appropriate debugger.

> [src/main.rs:4] x = 5

How to differentiate the value of 'x' for a given thread/instance/whatever? Don't add the info by hand to the debug message.

edit: typo

[root_axis]

Using a debugger for testing multi-threaded code is particularly painful. Tests and logs are especially superior in this case because you can make complex assertions that capture emergent behavior of a multi-threaded application. Pausing threads to step through them can often make it harder to observe the behavior you might expect to see when multiple threads are working together in real time.