There's quite a few nifty little things in this one.

I'm not sure I like the child_spec change, personally I like the supervision mode to be explicit when calling children.

I do like the developer tools, the breakpoint support, the UTF8 for atoms (which I'm realizing we may want in our DSL since we're converting user input strings to atoms), and the @impl that allows to explicitly declare which functions are there for an interface.

Overall, it's amazing to be part of the elixir community, rarely have I seen such emulation, positivity, speed of growth, and effectiveness achieved so fast for a language. Congrats @josevalim for bring the power of BEAM through a wonderful syntax!