I have a trait MyTrait, and I want all trait objects &dyn MyTrait to be comparable to each other and to nothing else. I have that now based on How to test for equality between trait objects?. T...

trait FooTrait {} struct FooStruct; impl FooTrait for FooStruct {} fn main() { let maybe_struct: Option<dyn FooStruct> = None; // Does not compile let maybe_trait: Option<Box<dyn...

First of all, I'm not asking what's the difference between &mut and ref mut per se. I'm asking because I thought: let ref mut a = MyStruct is the same as let a = &mut MyStruct Consid...

When writing code with traits you can put the trait in a trait bound: use std::fmt::Debug; fn myfunction1<T: Debug>(v: Box<T>) { println!("{:?}", v); } fn myfunction2<T: Debug&gt...

I have the following code: extern crate futures; // 0.1.24 use futures::Future; use std::io; struct Context; pub trait MyTrait { fn receive(context: Context) -> Future<Item = (), Error =...

I am struggling with the basics of object safety. If I have this code struct S { x: i32, } trait Trait: Sized { fn f(&self) -> i32 where Self: Sized; } fn object_safety_dynamic(x: Trai...

I cannot get this to compile without using a closure. I'm trying to get the function apply to return the correct kind of closure in the first place. #![feature(conservative_impl_trait)] #![allow(d...

Can anyone tell what the problem is with the following code? The compiler is complaining about lifetimes, but the error message makes absolutely no sense. I've tried everything I could think of, bu...

I have the following code extern crate rand; use rand::Rng; pub struct Randomizer { rand: Box<Rng>, } impl Randomizer { fn new() -> Self { let mut r = Box::new(rand::thread_rng()); /...

I have originally asked this question here, but it was marked as duplicate, although it duplicates only a part of it in my opinion, so I have created a more specific one: Consider the following co...

I'd like to send a trait object between threads, but can't figure out if it's possible. It seems like it might not be, as they apparently do not fulfill the Send trait. The following code demonstr...