指定特征边界时如何指定临时生命周期？

Question

I would like to declare a struct that wraps a generic type T like this:

use std::ops::Add;
struct MyStruct<T> where T: Add<&T, Output=T> {
    t: T
}

This fails with:

error[E0637]: `&` without an explicit lifetime name cannot be used here
 --> src/lib.rs:3:33
  |
3 | struct MyStruct<T> where T: Add<&T, Output=T> {
  |                                 ^ explicit lifetime name needed here

error[E0310]: the parameter type `T` may not live long enough

How can I tell the compiler that &T may be a temporary variable, and therefore any lifetime is ok?

I don't want to change my struct signature to MyStruct<'a, T> , as that makes the usage more verbose and complicated.

Answer 1

use std::ops::Add;
struct MyStruct<T> where T: for <'a> Add<&'a T, Output=T> {
    t: T
}

Playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=864f6c2ad80544adfa7da96cef8eb69c