#![allow(incomplete_features)] #![feature(const_trait_impl, try_trait_v2)] use std::ops::FromResidual; impl const FromResidual for T { //~^ ERROR const `impl` for trait `FromResidual` which is not marked with `#[const_trait]` //~| type parameter `T` must be used as the type parameter for some local type fn from_residual(t: T) -> _ { //~^ the placeholder `_` is not allowed t } } fn main() {}