#![feature(const_trait_impl)] #[const_trait] pub trait Plus { fn plus(self, rhs: Self) -> Self; } impl const Plus for i32 { fn plus(self, rhs: Self) -> Self { self + rhs } } impl Plus for u32 { fn plus(self, rhs: Self) -> Self { self + rhs } } pub const fn add_i32(a: i32, b: i32) -> i32 { a.plus(b) // ok } pub const fn add_u32(a: u32, b: u32) -> u32 { a.plus(b) //~^ ERROR cannot call } fn main() {}