whiteout provides macros that erase the type of any value into an impl Trait for a given trait. This gives you a value that can only be use with the methods of that trait, and whose type is unnameable.
#[macro_use] extern crate whiteout;
fn main() {
let a = erase!(10, std:ops::Add<i64, Output=i64>);
assert_eq!(a + 10, 20);
}Since we sometimes want to use these values together, whiteout provides both a one-time macro and a macro that produces a function which returns a consistent unnameable type, allowing multiple erased values to be used in conjunction. See the documentation for more info.