The new formatter is a wonderful addition. But the change I am most interested in is the improved mix xref.
I am working on a big Phoenix application, and compile times have reached a point when they are starting to get painful. Big recompilations are slow and frequent.
About a month ago I was able to use mix xref to introspect the module dependencies and improve compilation times slightly. This week I started to play with Elixir 1.6 RC and the new options have helped me to find much more issues that I could not see before.
Introspecting the module dependencies on a big application is never an easy task, but with the new mix xref options it is somewhat easier to filter and select what you want to see.
