How to add extension method for closures

help
#1

Hey all,

I would like to add extension methods for closures. What I would like to achieve is the following:

    #[test]
    fn test_method() {
        (|| panic!("error")).do_something();
    }

So what I want is to add the do_something method for closures. As far as I know, traits can be used to extend existing types. In other contexts I have successfully extended existing types such as String, but this time I could not make it work.

Here is what I tried:

trait Behaviour {
    fn do_something();
}

impl<T> Behaviour for T where T: FnOnce() {
    fn do_something(){
        println!("some test")

    }
}

But I got the following compilation error when I try to run above specified test:

no method named `do_something` found for closure `[closure@src\doer.rs:23:9: 23:29]` in the current scope

this is an associated function, not a method

Could you please help me and point it out where my problem lies and how to add extension method for closures?

Thanks in advance!

#2

It works.

Just make sure do_something is a method (takes self, &self or &mut self) and not an associated function.

2 Likes
#3

damn, I was close, thanks a lot!