How to constrain the element type of an iterator?

Question

I’m converting some older Rust code to work on 1.0.0. I need to convert a function that takes an iterator over characters, which used to be written like this:

Answer 1

fn f>(char_iter: I)

Associated types were recently added to the language, and many library types were updated to take advantage of them. For example, Iterator defines one associated type, named Item. You can add a constraint on the associated type by writing the name of the associated type, an equals sign, and the type you need.