Where is implicitness used?

As far as I know, Rust tries to be explicit with most things. However there are some places, where things are done implicitly, either due to ergonomics or for other reasons.

Is there a comprehensive list somewhere? If not, would you like to list some that you are aware of?

I think it is good for anyone that tries to learn the language.

EDIT: This is already a treasure! Thank you everyone!