I think you originally intended explicit type notation. I recently discovered actual type doesn't matter that much, and the point is having an interface/protocol which enable compiler validation and tooling support. I learned this truth from Objective-C and Go. That's why I told actual typing system itself not important. Objective-C protocol is nothing about type, but defines nice interface for tooling support. Go interface defines set of promises, so actual object structure doesn't matter.

Furthermore, recent languages offer automatic type inference - Haskell, Go, C++11. They force to retain type information, but also permit to elide them where accurately inference-able/deduce-able.

This is completely different with not forcing type notion such as Python, Ruby, Lua, JS. In these languages, it is fundamentally impossible to track complete type information. But in explicitly type notated languages, it's possible to track complete type informations even they're elided.

I think those type-(notation)-less languages are making some efforts to offer type informations by adding annotations. But I don't think that's really meaningful, because that's not enforced, and community doesn't care much.