It's quite annoying at the beginning that the errors you get make you believe that 'closure' is a type in itself, because the errors themselves quote the word as if it was some kind of type, but then you can't specify something like let f: closure = ....
this post was submitted on 11 Sep 2025
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Well, the closure has a type. Just you cannot declare it. That's why you do "impl Fn" instead. Because you know that whatever type the close is, it implements the "Fn" trait.
Do you have a different recommendation for how to display unnameable types in error messages? I'm sure the compiler team would consider any suggestions.